WO2024048325A1 - Light source device, ranging device, and ranging method - Google Patents

Light source device, ranging device, and ranging method Download PDF

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Publication number
WO2024048325A1
WO2024048325A1 PCT/JP2023/029829 JP2023029829W WO2024048325A1 WO 2024048325 A1 WO2024048325 A1 WO 2024048325A1 JP 2023029829 W JP2023029829 W JP 2023029829W WO 2024048325 A1 WO2024048325 A1 WO 2024048325A1
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WO
WIPO (PCT)
Prior art keywords
wavelength
light
reflective layer
light source
source device
Prior art date
Application number
PCT/JP2023/029829
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French (fr)
Japanese (ja)
Inventor
健二 田中
元 米澤
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ソニーグループ株式会社
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Publication of WO2024048325A1 publication Critical patent/WO2024048325A1/en

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Classifications

    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01C—MEASURING DISTANCES, LEVELS OR BEARINGS; SURVEYING; NAVIGATION; GYROSCOPIC INSTRUMENTS; PHOTOGRAMMETRY OR VIDEOGRAMMETRY
    • G01C3/00—Measuring distances in line of sight; Optical rangefinders
    • G01C3/02—Details
    • G01C3/06—Use of electric means to obtain final indication
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
    • G01S7/00—Details of systems according to groups G01S13/00, G01S15/00, G01S17/00
    • G01S7/48—Details of systems according to groups G01S13/00, G01S15/00, G01S17/00 of systems according to group G01S17/00
    • G01S7/483—Details of pulse systems
    • G01S7/484—Transmitters
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01S—DEVICES USING THE PROCESS OF LIGHT AMPLIFICATION BY STIMULATED EMISSION OF RADIATION [LASER] TO AMPLIFY OR GENERATE LIGHT; DEVICES USING STIMULATED EMISSION OF ELECTROMAGNETIC RADIATION IN WAVE RANGES OTHER THAN OPTICAL
    • H01S3/00—Lasers, i.e. devices using stimulated emission of electromagnetic radiation in the infrared, visible or ultraviolet wave range
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01S—DEVICES USING THE PROCESS OF LIGHT AMPLIFICATION BY STIMULATED EMISSION OF RADIATION [LASER] TO AMPLIFY OR GENERATE LIGHT; DEVICES USING STIMULATED EMISSION OF ELECTROMAGNETIC RADIATION IN WAVE RANGES OTHER THAN OPTICAL
    • H01S3/00—Lasers, i.e. devices using stimulated emission of electromagnetic radiation in the infrared, visible or ultraviolet wave range
    • H01S3/09—Processes or apparatus for excitation, e.g. pumping
    • H01S3/091—Processes or apparatus for excitation, e.g. pumping using optical pumping
    • H01S3/094—Processes or apparatus for excitation, e.g. pumping using optical pumping by coherent light
    • H01S3/0941—Processes or apparatus for excitation, e.g. pumping using optical pumping by coherent light of a laser diode
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01S—DEVICES USING THE PROCESS OF LIGHT AMPLIFICATION BY STIMULATED EMISSION OF RADIATION [LASER] TO AMPLIFY OR GENERATE LIGHT; DEVICES USING STIMULATED EMISSION OF ELECTROMAGNETIC RADIATION IN WAVE RANGES OTHER THAN OPTICAL
    • H01S3/00—Lasers, i.e. devices using stimulated emission of electromagnetic radiation in the infrared, visible or ultraviolet wave range
    • H01S3/10—Controlling the intensity, frequency, phase, polarisation or direction of the emitted radiation, e.g. switching, gating, modulating or demodulating
    • H01S3/11—Mode locking; Q-switching; Other giant-pulse techniques, e.g. cavity dumping
    • H01S3/1123—Q-switching
    • H01S3/113—Q-switching using intracavity saturable absorbers
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01S—DEVICES USING THE PROCESS OF LIGHT AMPLIFICATION BY STIMULATED EMISSION OF RADIATION [LASER] TO AMPLIFY OR GENERATE LIGHT; DEVICES USING STIMULATED EMISSION OF ELECTROMAGNETIC RADIATION IN WAVE RANGES OTHER THAN OPTICAL
    • H01S5/00—Semiconductor lasers
    • H01S5/04—Processes or apparatus for excitation, e.g. pumping, e.g. by electron beams
    • H01S5/042—Electrical excitation ; Circuits therefor
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01S—DEVICES USING THE PROCESS OF LIGHT AMPLIFICATION BY STIMULATED EMISSION OF RADIATION [LASER] TO AMPLIFY OR GENERATE LIGHT; DEVICES USING STIMULATED EMISSION OF ELECTROMAGNETIC RADIATION IN WAVE RANGES OTHER THAN OPTICAL
    • H01S5/00—Semiconductor lasers
    • H01S5/10—Construction or shape of the optical resonator, e.g. extended or external cavity, coupled cavities, bent-guide, varying width, thickness or composition of the active region
    • H01S5/14—External cavity lasers

Definitions

  • the present disclosure relates to a light source device, a distance measuring device, and a distance measuring method.
  • Laser technology is widely used in various fields such as microfabrication, medical care, and distance measurement.
  • short-pulse laser technology is expected to be applied to high-precision processing technology and highly efficient wavelength conversion technology.
  • a light source device using a Q switch is used in a wide range of application fields because it can obtain a high peak power exceeding kW (kilowatt) with a relatively simple configuration.
  • a light source device has been proposed in which the resonators for excitation light and oscillation light are overlapped to reduce the size and improve the peak power (see, for example, Patent Documents 1 and 2).
  • light source devices have been used as light sources for laser distance measuring devices LiDAR (Light Detection and Range). Since the high peak power of a light source device can increase the measuring distance, there is a demand for a light source device that can be miniaturized and has a high peak power.
  • LiDAR Light Detection and Range
  • the high peak power of the light source device can increase the distance measurement distance, making it possible to measure distances in further distant areas.
  • a high peak power may pose a problem in terms of laser safety.
  • the peak power can be easily changed by changing the driving method determined by the current value and injection time.
  • the peak power is determined by the Q value determined by the structure of the resonator and the characteristics of the laser medium and saturable absorption material used. Once decided, it was difficult to make it variable.
  • the present disclosure provides a light source device that can be downsized and has variable peak power using a passive Q switch of a solid-state laser.
  • a laminated semiconductor layer having an active layer that emits light of a first wavelength that changes depending on driving conditions; and a first reflective layer for the first wavelength; a second reflective layer for a second wavelength disposed on a first surface facing the light emitting surface of the laminated semiconductor layer; a third reflective layer for the first wavelength, disposed on a second surface disposed on the rear side of the optical axis from the first surface; a laser medium disposed between the second reflective layer and the third reflective layer; a fourth reflective layer for the second wavelength, which is disposed on the second surface or on the rear side of the optical axis from the second surface; a first resonator that causes light of the first wavelength to resonate between the first reflective layer and the third reflective layer; Equipped with The optical axis of the laminated semiconductor layer and the optical axis of the laser medium are arranged on one axis, A light source device is provided.
  • the driving conditions may include at least one of a driving current injected into the active layer or a temperature of the active layer.
  • the active layer emits one of at least two types of light having the first wavelength, each of which has a different wavelength, depending on the drive current,
  • the third reflective layer may have different reflectances for the at least two types of first wavelengths.
  • the active layer emits the longer light of the first wavelength as the drive current is larger,
  • the third reflective layer may have a higher reflectance as the first wavelength is longer.
  • the active layer emits the longer light of the first wavelength as the drive current is larger,
  • the third reflective layer may have a lower reflectance as the first wavelength is longer.
  • the first wavelength includes a third wavelength emitted when a first drive current is passed through the active layer, and a fourth wavelength emitted when a second drive current is passed through the active layer,
  • the third reflective layer may have different reflectances for the third wavelength and the fourth wavelength.
  • the third reflective layer has a higher reflectance for the fourth wavelength than a reflectance for the third wavelength,
  • the laser medium may not excite the second wavelength with respect to the third wavelength, and may excite the second wavelength with respect to the fourth wavelength.
  • the third reflective layer has a lower reflectance for the fourth wavelength than a reflectance for the third wavelength,
  • the laser medium may not excite the second wavelength with respect to the fourth wavelength, and may excite the second wavelength with respect to the third wavelength.
  • the third wavelength may be shorter than the fourth wavelength.
  • the laminated semiconductor layer has a plurality of first regions that each emit light of a different first wavelength
  • the third reflective layer may be provided corresponding to the plurality of first regions, and may have a plurality of second regions each having a different reflectance with respect to the first wavelength.
  • the laminated semiconductor layer has a plurality of first regions that emit light of the third wavelength or the fourth wavelength
  • the third reflective layer may be provided corresponding to the plurality of first regions, and may have a plurality of second regions having mutually different reflectances for the third wavelength and the fourth wavelength.
  • the laminated semiconductor layer may intermittently emit light of the first wavelength.
  • It may further include a second resonator that causes the light of the second wavelength to resonate between the second reflective layer and the fourth reflective layer.
  • the optical axis of the laminated semiconductor layer, the optical axis of the laser medium, and the optical axis of the saturable absorber may be arranged on one axis.
  • the light at the second wavelength may have a larger peak power than the light at the first wavelength.
  • the fourth reflective layer may emit Q-switched pulse wave light of the second wavelength.
  • a light source device that can emit light by switching wavelengths, A light receiving section, a distance measuring unit that measures the distance to the target object based on the light emission signal and the light reception signal of the light reception unit when the light emission signal of the light source device is reflected by the target object and received by the light reception unit; , comprising:
  • the light source device includes: a laminated semiconductor layer having an active layer that emits light of a first wavelength that changes depending on driving conditions; and a first reflective layer for the first wavelength; a second reflective layer for a second wavelength disposed on a first surface facing the light emitting surface of the laminated semiconductor layer; a third reflective layer for the first wavelength, disposed on a second surface disposed on the rear side of the optical axis from the first surface; a laser medium disposed between the second reflective layer and the third reflective layer; a fourth reflective layer for the second wavelength, which is disposed on the second surface or on the rear side of the optical axis from the second surface; a first resonator that causes light of
  • It may also include a drive unit that controls the drive conditions according to the distance to the target object.
  • the driving unit may switch and control the peak power of the light emission signal emitted from the light source device according to the distance to the target object.
  • the distance to the target object is measured based on the light emitting signal and the light receiving signal of the light receiving section.
  • the light source device includes: a laminated semiconductor layer having an active layer that emits light of a first wavelength that changes depending on driving conditions; and a first reflective layer for the first wavelength; a second reflective layer for a second wavelength disposed on a first surface facing the light emitting surface of the laminated semiconductor layer; a third reflective layer for the first wavelength, disposed on a second surface disposed on the rear side of the optical axis from the first surface; a laser medium disposed between the second reflective layer and the third reflective layer; a fourth reflective layer for the second wavelength, disposed on the second surface or disposed on the rear side of the optical axis from the second surface; a first resonator that causes light of the first wavelength to resonate between the first reflective layer and the third reflective layer; a second resonator that resonates light of the second wavelength between the second reflective layer and the fourth reflective layer,
  • the optical axis of the laminated semiconductor layer and the optical axis of the laser medium are arranged on one axis, A ranging method is provided.
  • FIG. 3 is a diagram showing how the first wavelength emitted by the active layer changes depending on the drive current.
  • FIG. 3 is a diagram showing how the first wavelength emitted by the active layer changes depending on the temperature.
  • FIG. 6 is a diagram showing how the reflectance of the third reflective layer changes depending on the first wavelength. This is a graph in which the section ⁇ a to ⁇ d is extracted from the graph in FIG. 4A. This is a graph in which the section ⁇ c to ⁇ f is extracted from the graph in FIG. 4A.
  • FIG. 7 is a diagram illustrating checkered pattern light emission of the light source device in the second embodiment.
  • FIG. 7 is a diagram showing light emission in a line and space pattern of a light source device in a second embodiment. It is a figure showing the pulse current given to the active layer in a 3rd embodiment. It is a figure showing the output of the 1st oscillation light L1 in a 3rd embodiment.
  • FIG. 3 is a diagram showing the output of second oscillation light L2.
  • FIG. 12 is a diagram illustrating a configuration example of a distance measuring device as an example of implementation of a light source device according to a fourth embodiment.
  • FIG. 6 is a diagram illustrating a laser beam emitting operation of a light source device when a subject is located at a short distance from a distance measuring device.
  • FIG. 6 is a diagram illustrating a laser beam emitting operation of a light source device when a subject is far away from a distance measuring device.
  • FIG. 1 is a block diagram showing an example of a schematic configuration of a vehicle control system.
  • FIG. 2 is an explanatory diagram showing an example of installation positions of an outside-vehicle information detection section and an imaging section.
  • FIG. 1 is a schematic diagram showing the configuration of a light source device 1 according to the first embodiment.
  • the light source device 1 is used, for example, as a medical laser or a light source for a distance measuring device, which will be described later.
  • the light source device 1 includes an excitation light source (laminated semiconductor layer) 2 and a laser medium 3. Further, the light source device 1 may include a saturable absorber 4.
  • the excitation light source 2 emits first oscillation light L1 for exciting the laser medium 3.
  • the excitation light source 2 is composed of semiconductor layers having a laminated structure in which a substrate 21, a fifth reflective layer R5, a cladding layer 22, an active layer 23, a cladding layer 24, and a first reflective layer R1 are laminated in this order.
  • the excitation light source 2 in FIG. 1 has a bottom emission type configuration in which the first continuous wave (CW) oscillation light L1 is emitted from the substrate 21, but the CW excitation light is emitted from the first reflective layer R1 side.
  • a top-emission type configuration is also possible.
  • the substrate 21 is, for example, an n-GaAs substrate. Since the n-GaAs substrate absorbs the first oscillation light L1, which is the excitation wavelength of the excitation light source 2, at a constant rate, it is desirable to make it as thin as possible in order to suppress absorption. On the other hand, it is desirable to have a thickness sufficient to maintain mechanical strength when joining, for example, to other members.
  • the active layer 23 performs surface emission of the first oscillation light L1.
  • the cladding layers 22 and 24 are, for example, AlGaAs cladding layers.
  • the first reflective layer R1 reflects the first oscillation light L1.
  • the fifth reflective layer R5 has a constant transmittance with respect to the first oscillation light L1.
  • a semiconductor distributed reflector (DBR) capable of electrical conduction is used.
  • DBR semiconductor distributed reflector
  • FIG. 2 is a cross-sectional view showing the support structure of the excitation light source 2 in the first embodiment.
  • the laser medium 3 shown in FIG. 1 is arranged on the substrate 21 in FIG. 2, and the saturable absorber 4 may be further arranged thereon.
  • the excitation light source 2 has an n-type contact layer 25 in addition to the stacked structure shown in FIG.
  • the contact layer 25 is laminated between the substrate 21 and the fifth reflective layer R5.
  • the contact layer 25 is electrically connected to the fifth reflective layer R5, the cladding layer 22, the active layer 23, the cladding layer 24, and the conductive layer 58 that covers the sidewalls of the first reflective layer R1.
  • the conductive layer 58 is an n-type metal layer, and insulating layers 59a and 59b are arranged around the conductive layer 58.
  • the support body 5 has a configuration in which a submount member 52 is arranged on a mount member 51. On the submount member 52, wiring layers 53a and 53b are arranged separately from each other. The wiring layer 53a is electrically connected to the conductive layer 57 stacked on the first reflective layer R1 via solder layers 56a and 56b. Conductive layer 57 is a p-type metal layer.
  • Pins 54a and 54b are attached to the mount member 51.
  • the pins 54a and 54b are arranged to penetrate the mount member 51 and are connected to a drive power source (not shown).
  • the pins 54a and 54b are connected to the wiring layers 53a and 53b by wires 55a and 55b, respectively.
  • the voltage applied to the pin 54a is applied to the first reflective layer R1 via the wire 55a, the wiring layer 53a, the solder layer 56a, and the conductive layer 57. Further, the voltage applied to the pin 54b is applied to the contact layer 25 via the wire 55b, the wiring layer 53b, the solder layer 56b, and the conductive layer 58.
  • a driving current is injected into the active layer 23 according to the potential difference between the voltage applied to the first reflective layer R1 and the voltage applied to the contact layer 25.
  • the wavelength of the first oscillation light L1 is referred to as a first wavelength ⁇ 1.
  • the first wavelength ⁇ 1 varies depending on the semiconductor material within the excitation light source 2.
  • the first wavelength ⁇ 1 also changes depending on driving conditions.
  • the driving conditions depend on, for example, the temperature of the active layer 23 or the above-mentioned driving current.
  • FIG. 3A is a diagram showing how the first wavelength ⁇ 1 emitted from the active layer 23 changes depending on the drive current.
  • the horizontal axis indicates the amount of drive current, and the vertical axis indicates the wavelength of the first oscillation light L1.
  • the active layer 23 emits the first oscillation light L1 having a longer wavelength as the driving current increases.
  • the third wavelength ⁇ 3 emitted when the first drive current I1 is applied and the fourth wavelength ⁇ 4 emitted when the second drive current I2 is applied are collectively referred to as the first wavelength ⁇ 1.
  • the first drive current I1 is assumed to be smaller than the second drive current I2.
  • the third wavelength ⁇ 3 is shorter than the fourth wavelength ⁇ 4.
  • FIG. 3B is a diagram showing how the first wavelength ⁇ 1 emitted from the active layer 23 changes depending on the temperature.
  • the horizontal axis represents the temperature of the active layer 23, and the vertical axis represents the wavelength.
  • the third wavelength ⁇ 3' emitted at the first temperature T1 and the fourth wavelength ⁇ 4' emitted at the second temperature T2 are collectively referred to as a first wavelength ⁇ 1.
  • the active layer 23 can switch and emit at least two types of first oscillation light L1, each having a different wavelength, by controlling the drive current or temperature.
  • the fifth reflective layer R5 is arranged on the substrate 21, for example.
  • the fifth reflective layer R5 has a multilayer reflective film made of Alz1Ga1-z1As/Alz2Ga1-z2As (0 ⁇ z1 ⁇ z2 ⁇ 1) doped with an n-type dopant (for example, silicon).
  • the fifth reflective layer R5 is also called n-DBR.
  • the active layer 23 has, for example, a multiple quantum well layer in which an Alx1Iny1Ga1-x1-y1As layer and an Alx3Iny3Ga1-x3-y3As layer are laminated.
  • the first reflective layer R1 has a multi-reflective film made of, for example, Alz3Ga1-z3As/Alz4Ga1-z4As (0 ⁇ z3 ⁇ z4 ⁇ 1) doped with a p-type dopant (for example, carbon).
  • the first reflective layer R1 is also called p-DBR.
  • Each semiconductor layer (fifth reflective layer R5, cladding layer 22, active layer 23, cladding layer 24, and first reflective layer R1) in the excitation light source 2 as an excitation light resonator is formed by MOCVD (Metal Organic Chemical Vapor Deposition: It can be formed using a crystal growth method such as metalorganic vapor phase epitaxy (MBE) or molecular beam epitaxy (MBE). After the crystal growth, processes such as mesa etching for element isolation, formation of an insulating film, and vapor deposition of an electrode film are performed to enable driving by injection of a driving current.
  • MOCVD Metal Organic Chemical Vapor Deposition: It can be formed using a crystal growth method such as metalorganic vapor phase epitaxy (MBE) or molecular beam epitaxy (MBE).
  • MBE metalorganic vapor phase epitaxy
  • MBE molecular beam epitaxy
  • the excitation light source 2 may be any member that emits excitation light that can excite the laser medium 3, and does not necessarily need to be a semiconductor laser element. Further, the material used for the excitation light source 2 may be a crystalline material or an amorphous material such as ceramic. Furthermore, the excitation light source 2 only needs to be able to make the first oscillation light L1 enter the laser medium 3, and does not need to include an optical system such as a lens.
  • a laser medium 3 is arranged on the opposite side of the substrate 21 of the excitation light source 2 from the fifth reflective layer R5, that is, on the rear side of the optical axis.
  • the laser medium 3 has a second reflective layer R2 and a third reflective layer R3.
  • the second reflective layer R2 is arranged on the first surface S1 facing the light exit surface of the excitation light source 2.
  • the third reflective layer R3 is arranged on the second surface S2 on the rear side of the optical axis than the first surface S1.
  • the laser medium 3 is arranged between the second reflective layer R2 and the third reflective layer R3.
  • the laser medium 3 emits the second oscillation light L2 when excited by the first oscillation light L1.
  • the laser medium 3 is arranged to face the saturable absorber 4.
  • the optical axis of the excitation light source 2 and the optical axis of the laser medium 3 are arranged on one axis.
  • the wavelength of the second oscillation light L2 is referred to as a second wavelength ⁇ 2 in this specification.
  • the laser medium 3 includes, for example, YAG (yttrium aluminum garnet) crystal Yb:YAG doped with Yb (yttribium).
  • the laser medium 3 is not limited to Yb:YAG, and examples of the laser medium 3 include Nd:YAG, Nd:YVO4, Nd:YLF, Nd:glass, Yb:YAG, Yb:YLF, Yb:FAP, Yb:SFAP. , Yb:YVO, Yb:glass, Yb:KYW, Yb:BCBF, Yb:YCOB, Yb:GdCOB, and Yb:YAB.
  • the laser medium 3 may be a four-level solid-state laser medium or a three-level solid-state laser medium. However, since the appropriate excitation wavelength differs depending on each crystal, it is necessary to select the material of the laser medium 3 according to the first wavelength ⁇ 1.
  • a reflective layer (for example, a dielectric multilayer film) that reflects excitation light may be provided on the surface of the laser medium 3 on the laser output side (third reflective layer R3).
  • the second reflective layer R2 disposed on the excitation light source 2 side is, for example, the first oscillation light L1 of the first wavelength ⁇ 1 emitted from the excitation light source 2. and reflects the second oscillation light L2 of the second wavelength ⁇ 2 emitted from the laser medium 3 with a predetermined reflectance.
  • the third reflective layer R3 provided on the opposite side of the excitation light source 2 transmits, for example, the second oscillation light L2 of the second wavelength ⁇ 2 emitted from the laser medium 3. Further, the third reflective layer R3 has different reflectances for at least two types of first oscillation light L1 having different wavelengths depending on the above-described drive current.
  • FIG. 4A is a diagram showing how the reflectance R of the third reflective layer R3 changes depending on the wavelength of the first oscillation light L1.
  • the horizontal axis indicates the wavelength of the first oscillation light L1
  • the vertical axis indicates the reflectance R of the third reflective layer R3.
  • the reflectance R is approximately 100% at maximum.
  • the wavelengths are assumed to increase in the order of wavelength ⁇ a ⁇ b ⁇ c ⁇ d ⁇ e ⁇ f.
  • the reflectance R is constant between wavelengths ⁇ a and ⁇ b.
  • the reflectance R increases at wavelengths ⁇ b to ⁇ c.
  • the reflectance R is constant between wavelengths ⁇ c to ⁇ d, and the reflectance R at this time is the maximum.
  • the reflectance R decreases at wavelengths ⁇ d to ⁇ e.
  • the reflectance R is constant from the wavelength ⁇ e to the wavelength f, and the reflectance R at this time is the lowest.
  • FIG. 4B is an enlarged view of the wavelength ⁇ a to ⁇ d section of the graph of FIG. 4A.
  • the third wavelength ⁇ 3 described above may be between the wavelengths ⁇ a and ⁇ b.
  • the fourth wavelength ⁇ 4 may be between the wavelengths ⁇ c to ⁇ d.
  • the third reflective layer R3 has a reflectance Ra for the third wavelength ⁇ 3.
  • it has a reflectance Rb higher than the reflectance Ra.
  • the reflectance Rb may be approximately 100%.
  • the third reflective layer R3 totally reflects the first oscillation light L1 at the fourth wavelength ⁇ 4.
  • the first oscillation light L1 has the third wavelength ⁇ 3, a certain amount of light is transmitted.
  • FIG. 4C is an enlarged view of the wavelength ⁇ c to ⁇ f section of the graph of FIG. 4A.
  • the third wavelength ⁇ 3 described above may be between wavelengths ⁇ c and ⁇ d.
  • the fourth wavelength ⁇ 4 may be between wavelengths ⁇ e and ⁇ f.
  • the third reflective layer R3 has a reflectance Rb for the third wavelength ⁇ 3.
  • the fourth wavelength ⁇ 4 it has a reflectance Rc lower than the reflectance Rb.
  • the third reflective layer R3 totally reflects the first oscillation light L1 having the third wavelength ⁇ 3.
  • the first oscillation light L1 having the fourth wavelength ⁇ 4 is transmitted to some extent.
  • a dielectric multilayer film in which layers made of a high refractive index material and layers made of a low refractive index material are alternately laminated is used.
  • the thickness of the dielectric multilayer film is, for example, one quarter of the wavelength of the first oscillation light L1, and the total number of layers is from several to several hundred layers.
  • High refractive index materials for the dielectric multilayer film include Al2O3, HfO2, TiO2, ZrO2, Ta2O5, Nb2O5, ZnO2, and materials with a refractive index of 1.6 to 2.5, and low refractive index materials include SiO2.
  • a material having a refractive index of 1.2 to 1.6 is used, such as , Al2O3, and MgF2.
  • a method for forming the dielectric multilayer film is, for example, a chemical vapor deposition (CVD) method, a reactive sputtering method, a RAS method (Radical Assisted Sputtering), a vacuum deposition method, or an ion-assisted deposition method. Further, such reflective films may be formed on both main surfaces of the optical filter.
  • the layer structure, material, and film-forming method of the second reflective layer R2 and the third reflective layer R3 are not limited to the above examples.
  • the excitation light source 2 and the laser medium 3 constitute a first resonator 11.
  • Three reflective layers (first reflective layer R1, fifth reflective layer R5, and third reflective layer R3) are provided inside the first resonator 11. Therefore, the first resonator 11 has a coupled cavity structure.
  • the light source device 1 in FIG. 1 may include a saturable absorber 4 arranged to face the third reflective layer R3 of the laser medium 3.
  • the saturable absorber 4 has a fourth reflective layer R4.
  • the optical axis of the saturable absorber 4 is aligned on one axis with the optical axis of the excitation light source 2 and the optical axis of the laser medium 3.
  • the saturable absorber 4 is made of, for example, Cr:YAG, and is a member that absorbs light of a predetermined wavelength and has the property that the light absorption rate decreases due to saturation of light absorption.
  • the saturable absorber 4 absorbs, for example, the second oscillation light L2 and transmits the first oscillation light L1.
  • the saturable absorber 4 functions as a passive Q switch for the second oscillation light L2. That is, the light source device 1 becomes a passive Q-switched pulse laser device when outputting light of the second wavelength ⁇ 2.
  • the second oscillation light L2 emitted from the laser medium 3 enters the saturable absorber 4, the second oscillation light L2 is absorbed, and as the degree of absorption increases, the saturable absorber 4 transmits the second oscillation light L2. rate is increasing. Thereafter, when the electron density of the excited level increases and the excited level is filled, the saturable absorber 4 becomes transparent, the Q value of the optical resonator increases, and laser oscillation occurs.
  • the fourth reflective layer R4 is a partial reflective layer that functions as an output coupler.
  • the fourth reflective layer R4 is arranged on the rear side of the optical axis than the second surface S2. Specifically, it is arranged along the light exit surface of the saturable absorber 4. Note that, as described above, there may be a light source device 1 that does not have the saturable absorber 4. When the light source device 1 does not have the saturable absorber 4, the fourth reflective layer R4 may be arranged on the second surface S2. In this case, the second oscillation light L2, which is a continuous wave, is emitted from the fourth reflective layer R4, but its peak power is smaller than that of the Q-switched light emitted from the saturable absorber 4.
  • the excitation light source 2, laser medium 3, and saturable absorber 4 in the light source device 1 may be joined together. Furthermore, a spacer, a polarization control element, a heat exhaust member, or the like may be arranged between the excitation light source 2 and the laser medium 3 or between the laser medium 3 and the saturable absorber 4.
  • a passive Q-switched pulse laser device is used, for example, as a light emitting device for a distance measuring device.
  • a passive Q-switched pulse laser device irradiates a target object with pulsed light, and a distance measuring device receives the light reflected from the object, thereby measuring the distance to the object.
  • the pulsed light emitted from the passive Q-switched pulse laser device is suitable for irradiating an object at a long distance.
  • the pulsed light emitted from the passive Q-switched pulse laser device is suitable for irradiating an object at a long distance.
  • a light source device 1 according to the present embodiment described below is characterized in that the peak power of the emitted laser light can be switched.
  • 5A and 5B are diagrams explaining the operation of the light source device 1 according to this embodiment.
  • a drive current into the active layer 23 through an unillustrated electrode of the excitation light source 2
  • surface emission of the first oscillation light L1 is performed from the active layer 23.
  • the first oscillation light L1 having the third wavelength ⁇ 3 between the wavelengths ⁇ a and ⁇ b shown in FIG. 4B can be emitted from the active layer 23.
  • the first oscillation light L1 is transmitted through the third reflective layer R3. Therefore, since the laser medium 3 cannot sufficiently absorb the first oscillation light L1, it cannot excite the second oscillation light L2.
  • FIG. 5A shows how the first oscillation light L1 passes through the third reflective layer R3 with a broken line.
  • the first resonator 11 causes the first oscillation light L1 to resonate between the first reflective layer R1 of the excitation light source 2 and the third reflective layer R3 of the laser medium 3, and the third reflective layer R3
  • the first oscillation light L1 is emitted from the first oscillation light L1.
  • the first oscillation light L1 that has passed through the third reflective layer R3 passes through the saturable absorber 4, and further passes through the fourth reflective layer R4, and is emitted from the light source device 1.
  • the laser medium 3 and the saturable absorber 4 do not perform a Q-switch operation.
  • the light source device 1 functions as a laser device that emits first oscillation light L1 consisting of a continuous wave.
  • the peak power can be made variable by, for example, PWM (Pulse Width Modulation) driving, which will be described later.
  • the first oscillation light L1 having the fourth wavelength ⁇ 4 between the wavelengths ⁇ c to ⁇ d in FIG. 4B can be emitted from the active layer 23.
  • the third reflective layer R3 reflects the first oscillation light L1 with a reflectance Rb.
  • the first resonator 11 confines the power of the first oscillation light L1 between the first reflective layer R1 and the third reflective layer R3. Thereby, since the laser medium 3 can sufficiently absorb the first oscillation light L1, the laser medium 3 is excited and the second oscillation light L2 of the second wavelength is generated. That is, the first oscillation light L1 functions as excitation light.
  • the first oscillation light L1 having the third wavelength ⁇ 3 between the wavelengths ⁇ c to ⁇ d in FIG. 4C is emitted from the active layer 23.
  • the first oscillation light L1 is reflected by the third reflective layer R3 with a reflectance Rb and is confined within the first resonator 11, so that the laser medium 3 excites the second oscillation light L2.
  • FIG. 5B shows how the first oscillation light L1 is reflected by the third reflective layer R3 with a broken line.
  • the laser medium 3 and the saturable absorber 4 constitute the second resonator 12. That is, the light source device 1 in FIG. 5B has a structure in which the first resonator 11 and the second resonator 12 are integrated. Further, the first resonator 11 and the second resonator 12 have a structure in which a member (in the example of FIG. 5B, the laser medium 3) is shared between the second reflective layer R2 and the third reflective layer R3.
  • the second oscillation light L2 is absorbed by the saturable absorber 4 in the second resonator 12, and the output surface of the saturable absorber 4 No light is emitted from the fourth reflective layer R4 on the side.
  • the second resonator 12 causes the second oscillation light L2 to resonate between the second reflective layer R2 of the laser medium 3 and the fourth reflective layer R4 of the saturable absorber 4, and from the reflective layer R4 side.
  • the second oscillation light L2 is emitted as a Q-switched pulse wave.
  • the second oscillation light L2 in FIG. 5B Since the second oscillation light L2 in FIG. 5B performs a passive Q-switch operation, it has a larger peak power than the first oscillation light L1 in FIG. 5A.
  • the active layer 23 can emit the first oscillation light L1 having the third wavelength ⁇ 3 and the fourth wavelength ⁇ 4, which are arbitrary wavelengths.
  • the third wavelength ⁇ 3 is within the wavelengths ⁇ a to ⁇ b in FIG.
  • the reflectance for the fourth wavelength ⁇ 4 becomes high.
  • the laser medium 3 does not excite the second oscillation light L2 with respect to the first oscillation light L1 with the third wavelength ⁇ 3, and excites the second oscillation light L2 with respect to the first oscillation light L1 with the fourth wavelength ⁇ 4.
  • the reflectance for the fourth wavelength ⁇ 4 becomes low.
  • the laser medium 3 does not excite the second oscillation light L2 with respect to the first oscillation light L1 with the fourth wavelength ⁇ 4, and excites the second oscillation light L2 with respect to the first oscillation light L1 with the third wavelength ⁇ 3. Excite L2.
  • the third wavelength ⁇ 3 is between the wavelengths ⁇ a and ⁇ b in FIG. A case in which the light source device 1 emits the first oscillation light L1 when the first drive current I1 is injected into the drive current I1, and the light source device 1 emits the second oscillation light L2 when the second drive current I2 is injected will be described.
  • the active layer 23 can emit at least two types of first oscillation light L1 having different wavelengths depending on the drive current.
  • the third reflective layer R3 has different reflectances for different wavelengths of the first oscillation light L1. Thereby, depending on the drive current injected into the active layer 23, it is possible to switch whether the first oscillation light L1 is transmitted through the third reflective layer R3 or reflected by the third reflective layer R3.
  • the laser medium 3 When the first oscillation light L1 has the third wavelength ⁇ 3, the laser medium 3 does not excite the second oscillation light L2, so the light source device 1 emits the first oscillation light L1 with a relatively low peak power.
  • the first oscillation light L1 has the fourth wavelength ⁇ 4, the laser medium 3 excites the second oscillation light L2, so the light source device 1 emits the second oscillation light L2 in the form of a Q-switched pulse wave.
  • the first oscillation light L1 or the second oscillation light L2 with different peak powers can be switched. Can be emitted.
  • the light source device 1 of the present disclosure for example, in order to control peak power, it can be realized with a simpler configuration than a configuration in which components such as an optical element are added externally, or a configuration in which a mechanical drive is added. be. Therefore, manufacturing costs can be reduced and miniaturization possible.
  • the light source device 1 according to the second embodiment is characterized by having an array-like structure.
  • FIG. 6 is a sectional view showing the configuration of the light source device 1 in the second embodiment.
  • the excitation light source 2 has a plurality of first regions A1 that emit the first oscillation light L1.
  • the third reflective layer R3 has a second area A2 corresponding to the first area A1.
  • the first region A1 is divided into a plurality of sub-regions, and the driving conditions for the active layer 23 differ depending on the sub-regions.
  • two adjacent sub-regions within the first region A1 emit the first oscillation light L1 having mutually different first wavelengths ⁇ 1.
  • the second area A2 is also divided into a plurality of sub-areas. Two adjacent sub-regions in the second region A2 have reflectances that correspond to the wavelength of the first oscillation light L1 emitted by the corresponding sub-regions in the first region A1.
  • the first region A1 includes a sub-region A11 that emits the first oscillation light L1 with the third wavelength ⁇ 3, and a sub-region A12 that emits the first oscillation light L1 with the fourth wavelength ⁇ 4.
  • the second area A2 includes a sub area A21 into which the first oscillation light L1 from the sub area A11 is incident, and a sub area A22 into which the first oscillation light L1 from the sub area A12 is incident.
  • the sub-region A21 within the second region A2 has a reflectance Ra for the third wavelength ⁇ 3. Furthermore, the sub-area A22 within the second area A2 has a reflectance Rb for the fourth wavelength ⁇ 4.
  • a first oscillation light L1 with a low peak power and a second oscillation light L2 with a high peak power are respectively emitted from the fourth reflective layer R4.
  • FIG. 7A is a diagram showing checkered pattern light emission of the light source device 1 in the second embodiment.
  • the first oscillation light L1 and second oscillation light L2 can be emitted in a checkerboard pattern, as shown in FIG. 7A.
  • FIG. 7B is a diagram showing light emission in a line and space pattern of the light source device 1 in the second embodiment.
  • the first oscillation light L1 and the second oscillation light L2 can be emitted in a line-and-space pattern, as shown in FIG. 7B.
  • a plurality of first reflected lights L1 having different peak powers can be emitted simultaneously from the light source device 1. Therefore, for example, short-distance distance measurement and long-distance distance measurement can be performed at the same timing.
  • the light source device 1 of the first embodiment emits the continuous wave first oscillation light L1 or the Q-switched pulse wave second oscillation light L2 by switching the drive current injected into the active layer 23. toggle between The first oscillation light L1 can be pulsed light similarly to the second oscillation light L2.
  • the first oscillation light L1 is made into pulsed light by making the drive current injected into the active layer 23 into a pulsed current.
  • the light source device 1 of the third embodiment can be used as a pulsed light source that can switch between the first wavelength ⁇ 1 and the second wavelength ⁇ 2.
  • the first drive current I1 injected into the active layer 23 is a pulse current.
  • FIG. 8A is a diagram showing a pulse current waveform injected into the active layer 23. The horizontal axis shows time, and the vertical axis shows the magnitude of drive current.
  • a first drive current I1 which is a pulse current, is injected into the active layer 23 at predetermined time intervals ⁇ t'. By performing PWM control on the pulse width and pulse interval of the pulse current, the peak power of the first oscillation light L1 having the third wavelength ⁇ 3 can be arbitrarily adjusted.
  • FIG. 8B is a waveform diagram of the first oscillation light L1 emitted from the light source device 1 in the third embodiment.
  • the horizontal axis shows time, and the vertical axis shows peak power.
  • the excitation light source 2 in the third embodiment outputs the first oscillation light L1 having the peak power P1 and the first wavelength ⁇ 1 at each time interval ⁇ t' described above. That is, thereby, the light source device 1 of the third embodiment outputs the first oscillation light L1 having the first wavelength ⁇ 1 as a pulse wave similar to the second oscillation light L2.
  • FIG. 8C is a waveform diagram of the second oscillation light L2 emitted from the light source device.
  • the horizontal axis shows time, and the vertical axis shows peak power.
  • the light source device 1 outputs the second oscillation light L2 having the peak power P2 at every time interval ⁇ t.
  • the pulse interval (time interval ⁇ t') of the first oscillation light L1 is determined by the pulse interval of the drive current injected into the active layer 23.
  • the pulse interval (time interval ⁇ t) of the second oscillation light L2 depends on the materials and thicknesses of the laser medium 3 and the saturable absorber 4, the reflectance of the first to fourth reflective layers R1 to R4, and the active layer 23. It is determined by the drive current injected into the
  • the second drive current I2 may also be applied as a pulse current similarly to FIG. 8A. Thereby, the pulse interval of the second oscillation light L2 can be controlled not only by the above conditions but also by the pulse interval of the second drive current I2.
  • the light source device 1 of the third embodiment can turn the first oscillation light L1 of the third wavelength ⁇ 3 into pulsed light with an arbitrary pulse interval. Therefore, the light source device 1 can switch and emit pulsed light having different wavelengths, and the pulsed light emitted from the light source device 1 can be used, for example, as a light emission signal for distance measurement.
  • the light source device 1 of the present disclosure can be applied to, for example, a distance measuring device.
  • FIG. 9 shows a configuration example of a distance measuring device 60 as an example of implementation of the light source device 1 according to the fourth embodiment.
  • the distance measuring device 60 includes a light emitting section 61, a driving section 62, a power supply circuit 63, a light emitting side optical system 64, a light receiving side optical system 65, a light receiving section 66, a signal processing section 67, a control section 68, and a temperature detecting section 69. ing.
  • the light emitting section 61 has a light source device 1 as a light source, and the light emitting section 61 may have a plurality of light source devices 1, or may be constituted by light source devices 1 arranged in a predetermined manner, such as a matrix. Good too.
  • the driving section 62 is configured to include a power supply circuit 63 for driving the light emitting section 61.
  • the power supply circuit 63 generates a power supply current for the drive unit 62 based on an input current from, for example, a battery (not shown) provided in the distance measuring device 60.
  • the drive section 62 supplies a drive current to the active layer 23 of the light source device 1 disposed within the light emitting section 61 based on the power supply current.
  • the driving section 62 takes in a light emission signal indicating light emission from the light source device 1 from the light emitting section 61.
  • the light emission signal is supplied to a distance measuring section (distance measuring section) 68a of the control section 68.
  • the light emission signal may be supplied directly to the distance measuring section 68a, or may be supplied to the distance measuring section 68a via the light receiving section 66.
  • the drive unit 62 may change the drive current supplied to the active layer 23 depending on the distance to the distance measurement target (subject S in FIG. 9).
  • the light emitted from the light emitting unit 61 is irradiated onto the subject (object) S as a distance measurement target via the light emitting side optical system 64. Then, the reflected light from the subject S of the light irradiated in this way enters the light receiving surface of the light receiving section 66 via the light receiving side optical system 65.
  • the light receiving section 66 is, for example, a light receiving element such as a CCD (Charge Coupled Device) sensor or a CMOS (Complementary Metal Oxide Semiconductor) sensor, and receives reflected light from the subject S that enters through the light receiving side optical system 65 as described above. It receives light, converts it into an electrical signal, and outputs it.
  • a light receiving element such as a CCD (Charge Coupled Device) sensor or a CMOS (Complementary Metal Oxide Semiconductor) sensor
  • the light receiving unit 66 performs, for example, CDS (Correlated Double Sampling) processing, AGC (Automatic Gain Control) processing, etc. on the electrical signal obtained by photoelectrically converting the received light, and further performs A/D (Analog/Digital) conversion. Perform processing. Then, the signal as digital data (light reception signal) is output to the subsequent signal processing section 67.
  • CDS Correlated Double Sampling
  • AGC Automatic Gain Control
  • the light receiving section 66 of this example outputs a frame synchronization signal Fs to the driving section 62. This allows the driving section 62 to cause the light source device 1 in the light emitting section 61 to emit light at a timing corresponding to the frame period of the light receiving section 66.
  • the signal processing unit 67 is configured as a signal processing processor using, for example, a DSP (Digital Signal Processor).
  • the signal processing section 67 performs various signal processing on the light reception signal input from the light receiving section 66.
  • the control unit 68 includes, for example, a microcomputer having a CPU (Central Processing Unit), ROM (Read Only Memory), RAM (Random Access Memory), etc., or an information processing device such as a DSP, and controls the light emission by the light emission unit 61. It controls the driving section 62 for controlling the operation and controls the light receiving operation of the light receiving section 66.
  • a microcomputer having a CPU (Central Processing Unit), ROM (Read Only Memory), RAM (Random Access Memory), etc.
  • ROM Read Only Memory
  • RAM Random Access Memory
  • the control section 68 has a function as a distance measuring section 68a.
  • the distance measuring section 68a measures the distance to the subject S based on the light reception signal signal-processed by the signal processing section 67 and the light emission signal of the light source device 1 supplied from the driving section 62.
  • the distance measuring unit 68a of this example measures the distance of each part of the subject S to enable identification of the three-dimensional shape of the subject S.
  • the control unit 68 may notify the driving unit 62 of the distance to the subject S every time the distance measuring unit 68a measures the distance to the subject S.
  • the temperature detection section 69 detects the temperature of the light emitting section 61.
  • a configuration may be adopted in which temperature detection is performed using, for example, a diode.
  • information on the temperature detected by the temperature detection section 69 is supplied to the driving section 62, thereby enabling the driving section 62 to drive the light emitting section 61 based on the temperature information.
  • the distance measuring method in the distance measuring device 60 for example, a distance measuring method using an STL (Structured Light) method or a ToF (Time of Flight) method can be adopted.
  • STL Structured Light
  • ToF Time of Flight
  • the light receiving section 66 is, for example, an IR (Infrared) light receiving section using a global shutter method.
  • the distance measuring section 68a controls the driving section 62 so that the light emitting section 61 emits pattern light, and detects pattern distortion in the image signal obtained via the signal processing section 67. , calculate the distance based on how the pattern is distorted.
  • the ToF method measures the distance to the target object by detecting the flight time (time difference) of the light emitted from the light emitting unit 61 until it is reflected by the target object and reaches the light receiving unit 66. It is a method.
  • dToF direct ToF
  • SPAD Single Photon Avalanche Diode
  • the distance measuring section 68a calculates the time difference between light emission and light reception for the light emitted from the light emitting section 61 and received by the light receiving section 66 based on the signal inputted via the signal processing section 67, and calculates the time difference between light emission and light reception.
  • the distance to each part of the subject S is calculated based on the distance and the speed of light.
  • a light receiving portion capable of receiving IR light is used as the light receiving portion 66, for example.
  • the laser light emitted to the subject S may be switched depending on the distance to the subject S.
  • 10A and 10B are diagrams showing an example in which the light source device 1 in the distance measuring device 60 emits a laser beam to the subject S.
  • the control unit 68 notifies the driving unit 62 of the distance to the subject S every time the distance measuring unit 68a measures the distance to the subject S.
  • the peak power of the laser beam is low.
  • FIG. 10A is a diagram showing the laser beam emitting operation of the light source device 1 when the subject S is at a short distance from the distance measuring device 60.
  • the drive unit 62 injects the first drive current I1 into the active layer 23.
  • the active layer 23 emits the first oscillation light L1 having the third wavelength ⁇ 3. Since the first oscillation light L1 having the third wavelength ⁇ 3 is transmitted through the third reflective layer R3, the laser medium 3 does not excite the second oscillation light L2.
  • the light source device 1 emits the first oscillation light L1 with low peak power to the subject S.
  • the first oscillation light L1 irradiated onto the subject S is reflected by the subject S and received by the light receiving section 66, and short distance measurement is performed by the distance measuring section 68a.
  • the first reflected light L1 has a low peak power and does not reach far, so it is used for short distance measurement.
  • FIG. 10B is a diagram showing the laser beam emitting operation of the light source device 1 when the subject S is far away from the distance measuring device 60.
  • the drive unit 62 injects the second drive current I2 into the active layer 23.
  • the active layer 23 emits the first oscillation light L1 having the fourth wavelength ⁇ 4.
  • the excitation light L2 with the fourth wavelength ⁇ 4 is repeatedly reflected between the first reflective layer R1 and the third reflective layer R3, and a sufficient amount of the first reflected light L1 is absorbed by the laser medium 3. excites the second oscillation light L2.
  • the second oscillation light L2 is repeatedly reflected between the second reflection layer R2 and the fourth reflection layer R4, and when a sufficient amount of the second oscillation light L2 is absorbed by the saturable absorber 4, the light source device 1 emits the second oscillation light L2 with high peak power to the subject S.
  • the second oscillation light L2 is used for long distance measurement.
  • the drive unit 62 may switch the drive current injected into the active layer 23 based on the distance measurement result by the distance measurement device 60. Thereby, depending on the distance of the subject S, the light source device 1 can emit oscillated light with an optimal peak power.
  • the distance measuring device 60 of the fourth embodiment switches the emitted laser light according to the distance to the subject S using the light source device 1 of any of the first to third embodiments. be able to.
  • a laser beam with a higher peak power is emitted to a subject S at a far distance, and a laser beam with a lower peak power is emitted to a subject S at a close distance, taking laser safety into consideration. etc., laser light can be used depending on the situation.
  • the technology according to the present disclosure (this technology) can be applied to various products.
  • the technology according to the present disclosure may be realized as a device mounted on any type of moving body such as a car, electric vehicle, hybrid electric vehicle, motorcycle, bicycle, personal mobility, airplane, drone, ship, robot, etc. It's okay.
  • FIG. 11 is a block diagram illustrating a schematic configuration example of a vehicle control system, which is an example of a mobile body control system to which the technology according to the present disclosure can be applied.
  • the vehicle control system 12000 includes a plurality of electronic control units connected via a communication network 12001.
  • the vehicle control system 12000 includes a drive system control unit 12010, a body system control unit 12020, an outside vehicle information detection unit 12030, an inside vehicle information detection unit 12040, and an integrated control unit 12050.
  • a microcomputer 12051, an audio/image output section 12052, and an in-vehicle network I/F (interface) 12053 are illustrated.
  • the drive system control unit 12010 controls the operation of devices related to the drive system of the vehicle according to various programs.
  • the drive system control unit 12010 includes a drive force generation device such as an internal combustion engine or a drive motor that generates drive force for the vehicle, a drive force transmission mechanism that transmits the drive force to wheels, and a drive force transmission mechanism that controls the steering angle of the vehicle. It functions as a control device for a steering mechanism to adjust and a braking device to generate braking force for the vehicle.
  • the body system control unit 12020 controls the operations of various devices installed in the vehicle body according to various programs.
  • the body system control unit 12020 functions as a keyless entry system, a smart key system, a power window device, or a control device for various lamps such as a headlamp, a back lamp, a brake lamp, a turn signal, or a fog lamp.
  • radio waves transmitted from a portable device that replaces a key or signals from various switches may be input to the body control unit 12020.
  • the body system control unit 12020 receives input of these radio waves or signals, and controls the door lock device, power window device, lamp, etc. of the vehicle.
  • the external information detection unit 12030 detects information external to the vehicle in which the vehicle control system 12000 is mounted.
  • an imaging section 12031 is connected to the outside-vehicle information detection unit 12030.
  • the vehicle exterior information detection unit 12030 causes the imaging unit 12031 to capture an image of the exterior of the vehicle, and receives the captured image.
  • the external information detection unit 12030 may perform object detection processing such as a person, car, obstacle, sign, or text on the road surface or distance detection processing based on the received image.
  • the imaging unit 12031 is an optical sensor that receives light and outputs an electrical signal according to the amount of received light.
  • the imaging unit 12031 can output the electrical signal as an image or as distance measurement information.
  • the light received by the imaging unit 12031 may be visible light or non-visible light such as infrared rays.
  • the in-vehicle information detection unit 12040 detects in-vehicle information.
  • a driver condition detection section 12041 that detects the condition of the driver is connected to the in-vehicle information detection unit 12040.
  • the driver condition detection unit 12041 includes, for example, a camera that images the driver, and the in-vehicle information detection unit 12040 detects the degree of fatigue or concentration of the driver based on the detection information input from the driver condition detection unit 12041. It may be calculated, or it may be determined whether the driver is falling asleep.
  • the microcomputer 12051 calculates control target values for the driving force generation device, steering mechanism, or braking device based on the information inside and outside the vehicle acquired by the vehicle exterior information detection unit 12030 or the vehicle interior information detection unit 12040, Control commands can be output to 12010.
  • the microcomputer 12051 realizes ADAS (Advanced Driver Assistance System) functions, including vehicle collision avoidance or impact mitigation, following distance based on vehicle distance, vehicle speed maintenance, vehicle collision warning, vehicle lane departure warning, etc. It is possible to perform cooperative control for the purpose of ADAS (Advanced Driver Assistance System) functions, including vehicle collision avoidance or impact mitigation, following distance based on vehicle distance, vehicle speed maintenance, vehicle collision warning, vehicle lane departure warning, etc. It is possible to perform cooperative control for the purpose of
  • ADAS Advanced Driver Assistance System
  • the microcomputer 12051 controls the driving force generating device, steering mechanism, braking device, etc. based on information about the surroundings of the vehicle acquired by the vehicle exterior information detection unit 12030 or the vehicle interior information detection unit 12040. It is possible to perform cooperative control for the purpose of autonomous driving, etc., which does not rely on operation.
  • the microcomputer 12051 can output a control command to the body system control unit 12020 based on the information outside the vehicle acquired by the outside information detection unit 12030.
  • the microcomputer 12051 controls the headlamps according to the position of the preceding vehicle or oncoming vehicle detected by the vehicle exterior information detection unit 12030, and performs cooperative control for the purpose of preventing glare, such as switching from high beam to low beam. It can be carried out.
  • the audio and image output unit 12052 transmits an output signal of at least one of audio and images to an output device that can visually or audibly notify information to the occupants of the vehicle or to the outside of the vehicle.
  • an audio speaker 12061, a display section 12062, and an instrument panel 12063 are illustrated as output devices.
  • the display unit 12062 may include, for example, at least one of an on-board display and a head-up display.
  • FIG. 12 is a diagram showing an example of the installation position of the imaging section 12031.
  • the vehicle 12100 has imaging units 12101, 12102, 12103, 12104, and 12105 as the imaging unit 12031.
  • the imaging units 12101, 12102, 12103, 12104, and 12105 are provided, for example, at positions such as the front nose, side mirrors, rear bumper, back door, and the top of the windshield inside the vehicle 12100.
  • An imaging unit 12101 provided in the front nose and an imaging unit 12105 provided above the windshield inside the vehicle mainly acquire images in front of the vehicle 12100.
  • Imaging units 12102 and 12103 provided in the side mirrors mainly capture images of the sides of the vehicle 12100.
  • An imaging unit 12104 provided in the rear bumper or back door mainly captures images of the rear of the vehicle 12100.
  • the images of the front acquired by the imaging units 12101 and 12105 are mainly used for detecting preceding vehicles, pedestrians, obstacles, traffic lights, traffic signs, lanes, and the like.
  • FIG. 12 shows an example of the imaging range of the imaging units 12101 to 12104.
  • An imaging range 12111 indicates the imaging range of the imaging unit 12101 provided on the front nose
  • imaging ranges 12112 and 12113 indicate imaging ranges of the imaging units 12102 and 12103 provided on the side mirrors, respectively
  • an imaging range 12114 shows the imaging range of the imaging unit 12101 provided on the front nose.
  • the imaging range of the imaging unit 12104 provided in the rear bumper or back door is shown. For example, by overlapping the image data captured by the imaging units 12101 to 12104, an overhead image of the vehicle 12100 viewed from above can be obtained.
  • At least one of the imaging units 12101 to 12104 may have a function of acquiring distance information.
  • at least one of the imaging units 12101 to 12104 may be a stereo camera including a plurality of image sensors, or may be an image sensor having pixels for phase difference detection.
  • the microcomputer 12051 determines the distance to each three-dimensional object within the imaging ranges 12111 to 12114 and the temporal change in this distance (relative speed with respect to the vehicle 12100) based on the distance information obtained from the imaging units 12101 to 12104. In particular, by determining the three-dimensional object that is closest to the vehicle 12100 on its path and that is traveling at a predetermined speed (for example, 0 km/h or more) in approximately the same direction as the vehicle 12100, it is possible to extract the three-dimensional object as the preceding vehicle. can.
  • a predetermined speed for example, 0 km/h or more
  • the microcomputer 12051 can set an inter-vehicle distance to be secured in advance in front of the preceding vehicle, and perform automatic brake control (including follow-up stop control), automatic acceleration control (including follow-up start control), and the like. In this way, it is possible to perform cooperative control for the purpose of autonomous driving, etc., in which the vehicle travels autonomously without depending on the driver's operation.
  • the microcomputer 12051 transfers three-dimensional object data to other three-dimensional objects such as two-wheeled vehicles, regular vehicles, large vehicles, pedestrians, and utility poles based on the distance information obtained from the imaging units 12101 to 12104. It can be classified and extracted and used for automatic obstacle avoidance. For example, the microcomputer 12051 identifies obstacles around the vehicle 12100 into obstacles that are visible to the driver of the vehicle 12100 and obstacles that are difficult to see. Then, the microcomputer 12051 determines a collision risk indicating the degree of risk of collision with each obstacle, and when the collision risk exceeds a set value and there is a possibility of a collision, the microcomputer 12051 transmits information via the audio speaker 12061 and the display unit 12062. By outputting a warning to the driver via the vehicle control unit 12010 and performing forced deceleration and avoidance steering via the drive system control unit 12010, driving support for collision avoidance can be provided.
  • the microcomputer 12051 determines a collision risk indicating the degree of risk of collision with each obstacle, and when the collision risk exceed
  • At least one of the imaging units 12101 to 12104 may be an infrared camera that detects infrared rays.
  • the microcomputer 12051 can recognize a pedestrian by determining whether the pedestrian is present in the images captured by the imaging units 12101 to 12104.
  • pedestrian recognition involves, for example, a procedure for extracting feature points in images captured by the imaging units 12101 to 12104 as infrared cameras, and a pattern matching process is performed on a series of feature points indicating the outline of an object to determine whether it is a pedestrian or not.
  • the audio image output unit 12052 creates a rectangular outline for emphasis on the recognized pedestrian.
  • the display unit 12062 is controlled to display the .
  • the audio image output unit 12052 may control the display unit 12062 to display an icon or the like indicating a pedestrian at a desired position.
  • the technology according to the present disclosure can be applied to, for example, the imaging unit 12031 among the configurations described above.
  • the light source device 1 according to the present disclosure may be provided together with the imaging section 12031.
  • the present technology can have the following configuration. (1) a laminated semiconductor layer having an active layer that emits light of a first wavelength that changes depending on driving conditions; and a first reflective layer for the first wavelength; a second reflective layer for a second wavelength disposed on a first surface facing the light emitting surface of the laminated semiconductor layer; a third reflective layer for the first wavelength, disposed on a second surface disposed on the rear side of the optical axis from the first surface; a laser medium disposed between the second reflective layer and the third reflective layer; and a laser medium disposed on the second surface or on the rear side of the optical axis from the second surface.
  • the driving condition includes at least one of a driving current injected into the active layer or a temperature of the active layer.
  • the light source device according to (1) the active layer emits light of at least two types of the first wavelength, each having a different wavelength, depending on the drive current;
  • the third reflective layer has different reflectances for the at least two types of first wavelengths, The light source device according to (2).
  • the active layer emits the longer light of the first wavelength as the drive current is larger;
  • the third reflective layer has a higher reflectance as the first wavelength is longer.
  • the active layer emits the longer light of the first wavelength as the drive current is larger;
  • the third reflective layer has a lower reflectance as the first wavelength is longer.
  • the first wavelength includes a third wavelength emitted when the first drive current is passed through the active layer, and a fourth wavelength emitted when the second drive current is passed through the active layer.
  • the third reflective layer has different reflectances for the third wavelength and the fourth wavelength, The light source device according to (2) or (3).
  • the third reflective layer has a higher reflectance for the fourth wavelength than for the third wavelength; The laser medium does not excite the second wavelength with respect to the third wavelength, and excites the second wavelength with respect to the fourth wavelength.
  • the third reflective layer has a lower reflectance for the fourth wavelength than for the third wavelength; The laser medium does not excite the second wavelength with respect to the fourth wavelength, and excites the second wavelength with respect to the third wavelength.
  • the laminated semiconductor layer has a plurality of first regions that each emit light of a different first wavelength
  • the third reflective layer is provided corresponding to the plurality of first regions, and has a plurality of second regions each having a different reflectance with respect to the first wavelength.
  • the light source device according to any one of (1) to (9).
  • the laminated semiconductor layer has a plurality of first regions that emit light of the third wavelength or the fourth wavelength
  • the third reflective layer is provided corresponding to the plurality of first regions, and has a plurality of second regions having mutually different reflectances with respect to the third wavelength and the fourth wavelength.
  • (12) the laminated semiconductor layer intermittently emits light of the first wavelength;
  • the light source device according to any one of (1) to (9).
  • the light source device according to any one of (1) to (12).
  • (14) further comprising a saturable absorber having the fourth reflective layer, The optical axis of the laminated semiconductor layer, the optical axis of the laser medium, and the optical axis of the saturable absorber are arranged on one axis, The light source device according to any one of (1) to (13).
  • the light at the second wavelength has a larger peak power than the light at the first wavelength.
  • the light source device according to (14).
  • the fourth reflective layer emits Q-switched pulsed wave light of the second wavelength; The light source device according to (14) or (15).
  • a light source device capable of emitting light by switching the wavelength;
  • a light receiving section a distance measuring unit that measures the distance to the target object based on the light emission signal and the light reception signal of the light reception unit when the light emission signal of the light source device is reflected by the target object and received by the light reception unit;
  • the light source device includes: a laminated semiconductor layer having an active layer that emits light of a first wavelength that changes depending on driving conditions; and a first reflective layer for the first wavelength; a second reflective layer for a second wavelength disposed on a first surface facing the light emitting surface of the laminated semiconductor layer; a third reflective layer for the first wavelength, disposed on a second surface disposed on the rear side of the optical axis from the first surface; a laser medium disposed between the second reflective layer and the third reflective layer; and a laser medium disposed on the second surface or on the rear side of the optical axis from the second surface.
  • a fourth reflective layer for wavelength comprising a drive unit that controls the drive conditions according to the distance to the target object; The distance measuring device according to (17). (19) The drive unit switches and controls the peak power of the light emission signal emitted from the light source device according to the distance of the target object.
  • the light source device includes: a laminated semiconductor layer having an active layer that emits light of a first wavelength that changes depending on driving conditions; and a first reflective layer for the first wavelength; a second reflective layer for a second wavelength disposed on a first surface facing the light emitting surface of the laminated semiconductor layer; a third reflective layer for the first wavelength, disposed on a second surface disposed on the rear side of the optical axis from the first surface; a laser medium disposed between the second reflective layer and the third reflective layer; and a laser medium disposed on the second surface or on the rear side of the optical axis from the second surface.
  • a fourth reflective layer for wavelength; a first resonator that causes light of the first wavelength to resonate between the first reflective layer and the third reflective layer; a second resonator that resonates light of the second wavelength between the second reflective layer and the fourth reflective layer;
  • the optical axis of the laminated semiconductor layer and the optical axis of the laser medium are arranged on one axis, Distance measurement method.
  • 1 light source device 2 excitation light source, 3 laser medium, 4 saturable absorber, 5 support, 11 first resonator, 12 second resonator, 21 substrate, 22, 24 cladding layer, 23 active layer, 25 contact layer , 51 Mount member, 52 Submount member, 53a, 53b Wiring layer, 54a, 54b Pin, 55a, 55b Wire, 56a, 56b Solder layer, 57, 58 Conductive layer, 59a, 59b Insulating layer, 60 Distance measuring device, 61 Light emitting unit, 62 Drive unit, 63 Power supply circuit, 64 Light emitting side optical system, 65 Light receiving side optical system, 66 Light receiving unit, 67 Signal processing unit, 68 Control unit, 68a Distance measuring unit, 69 Temperature detection unit

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Abstract

[Problem] To enable a smaller form factor and variable peak power. [Solution] This light source device comprises: a laminated semiconductor layer having an active layer that emits light of a first wavelength, which is a wavelength that changes according to drive conditions, and a first reflective layer for the first wavelength; a second reflective layer for a second wavelength disposed on a first surface facing a light emission surface of the laminated semiconductor layer; a third reflective layer for the first wavelength disposed on a second surface disposed further to the rear side of the optical axis relative to the first surface; a laser medium disposed between the second reflective layer and the third reflective layer; a fourth reflective layer for the second wavelength disposed on the second surface or disposed further to the rear side of the optical axis relative to the second surface; and a first resonator that causes the light of the first wavelength to resonate between the first reflective layer and the third reflective layer. The optical axis of the laminated semiconductor layer and the optical axis of the laser medium are coaxial.

Description

光源装置、測距装置、及び測距方法Light source device, ranging device, and ranging method
　本開示は、光源装置、測距装置、及び測距方法に関する。 The present disclosure relates to a light source device, a distance measuring device, and a distance measuring method.
　レーザ技術は、微細加工、医療及び測距など種々の分野で幅広く利用されている。特に、短パルスレーザの技術は、高精度の加工技術及び高効率の波長変換技術に向けた応用が期待されている。その中でも、Ｑスイッチを用いた光源装置は、比較的簡便な構成でｋＷ（キロワット）を超える高いピークパワーが得られるため、幅広い応用分野で用いられている。例えば、励起光と発振光の共振器をオーバーラップさせることで、小型化及びピークパワーの向上を図った光源装置が提案されている（例えば、特許文献１、２参照）。 Laser technology is widely used in various fields such as microfabrication, medical care, and distance measurement. In particular, short-pulse laser technology is expected to be applied to high-precision processing technology and highly efficient wavelength conversion technology. Among them, a light source device using a Q switch is used in a wide range of application fields because it can obtain a high peak power exceeding kW (kilowatt) with a relatively simple configuration. For example, a light source device has been proposed in which the resonators for excitation light and oscillation light are overlapped to reduce the size and improve the peak power (see, for example, Patent Documents 1 and 2).
　特に近年では、光源装置はレーザ測距装置ＬｉＤＡＲ（Light Detection and Range）の光源として用いられている。光源装置の高いピークパワーは測距距離を大きくすることができるため、小型化可能で高いピークパワーを有する光源装置が求められている。 Particularly in recent years, light source devices have been used as light sources for laser distance measuring devices LiDAR (Light Detection and Range). Since the high peak power of a light source device can increase the measuring distance, there is a demand for a light source device that can be miniaturized and has a high peak power.
国際公開第２１／１０６７５７公報International Publication No. 21/106757 特開２０１５－１３８９３８号公報Japanese Patent Application Publication No. 2015-138938
　光源装置を測距装置の光源として用いる場合、光源装置の高いピークパワーは、測距距離を大きくすることができるため、さらなる遠方領域を測距することが可能になる。しかしながら、近距離領域を測距する場合、高いピークパワーのままでは、レーザ安全上問題となる場合があった。例えば、半導体レーザのような電流注入型のレーザは、電流値と注入時間で決まる駆動方法を変えることによって、ピークパワーを容易に変えることができる。しかし、固体レーザの受動Ｑスイッチを用いた光源装置をもちいる場合、共振器の構造や使用するレーザ媒質や可飽和吸収材料の特性によるＱ値によって、ピークパワーが決まるため、一旦共振器構造を決定すると、可変にすることが難しかった。 When the light source device is used as a light source for a distance measuring device, the high peak power of the light source device can increase the distance measurement distance, making it possible to measure distances in further distant areas. However, when measuring short distances, a high peak power may pose a problem in terms of laser safety. For example, in a current injection type laser such as a semiconductor laser, the peak power can be easily changed by changing the driving method determined by the current value and injection time. However, when using a light source device using a passive Q-switch of a solid-state laser, the peak power is determined by the Q value determined by the structure of the resonator and the characteristics of the laser medium and saturable absorption material used. Once decided, it was difficult to make it variable.
　本開示は、上記の課題を解決するために、固体レーザの受動Ｑスイッチを用いて、小型化が可能かつ、ピークパワーが可変である光源装置を提供するものである。 In order to solve the above problems, the present disclosure provides a light source device that can be downsized and has variable peak power using a passive Q switch of a solid-state laser.
　上記の課題を解決するために、本開示によれば、
　駆動条件に応じて変化する波長である第１波長の光を出射する活性層と、前記第１波長に対する第１反射層と、を有する積層半導体層と、
　前記積層半導体層の光出射面に対向する第１面に配置される第２波長に対する第２反射層と、
　前記第１面よりも光軸の後方側に配置される第２面に配置され、前記第１波長に対する第３反射層と、
　前記第２反射層及び前記第３反射層の間に配置されるレーザ媒質と、
　前記第２面に配置されるか、又は前記第２面より光軸の後方側に配置される、前記第２波長に対する第４反射層と、
　前記第１反射層及び前記第３反射層の間で前記第１波長の光を共振させる第１共振器と、
を備え、
　前記積層半導体層の光軸及び前記レーザ媒質の光軸は、一軸上に配置される、
光源装置が提供される。 In order to solve the above problems, according to the present disclosure,
a laminated semiconductor layer having an active layer that emits light of a first wavelength that changes depending on driving conditions; and a first reflective layer for the first wavelength;
a second reflective layer for a second wavelength disposed on a first surface facing the light emitting surface of the laminated semiconductor layer;
a third reflective layer for the first wavelength, disposed on a second surface disposed on the rear side of the optical axis from the first surface;
a laser medium disposed between the second reflective layer and the third reflective layer;
a fourth reflective layer for the second wavelength, which is disposed on the second surface or on the rear side of the optical axis from the second surface;
a first resonator that causes light of the first wavelength to resonate between the first reflective layer and the third reflective layer;
Equipped with
The optical axis of the laminated semiconductor layer and the optical axis of the laser medium are arranged on one axis,
A light source device is provided.
　前記駆動条件は、前記活性層に注入される駆動電流又は前記活性層の温度の少なくとも一方を含んでもよい。 The driving conditions may include at least one of a driving current injected into the active layer or a temperature of the active layer.
　前記活性層は、前記駆動電流に応じて、それぞれ波長が異なる少なくとも２種類の前記第１波長のいずれかの光を出射し、
　前記第３反射層は、前記少なくとも２種類の第１波長に対してそれぞれ異なる反射率を有してもよい。 The active layer emits one of at least two types of light having the first wavelength, each of which has a different wavelength, depending on the drive current,
The third reflective layer may have different reflectances for the at least two types of first wavelengths.
　前記活性層は、前記駆動電流が大きいほど、より長い前記第１波長の光を出射し、
　前記第３反射層は、前記第１波長が長いほど、反射率をより高くしてもよい。 The active layer emits the longer light of the first wavelength as the drive current is larger,
The third reflective layer may have a higher reflectance as the first wavelength is longer.
　前記活性層は、前記駆動電流が大きいほど、より長い前記第１波長の光を出射し、
　前記第３反射層は、前記第１波長が長いほど、反射率をより低くしてもよい。 The active layer emits the longer light of the first wavelength as the drive current is larger,
The third reflective layer may have a lower reflectance as the first wavelength is longer.
　前記第１波長は、前記活性層に第１駆動電流を流すときに出射される第３波長と、前記活性層に第２駆動電流を流すときに出射される第４波長とを含み、
　前記第３反射層は、前記第３波長及び前記第４波長に対して、互いに異なる反射率を有してもよい。 The first wavelength includes a third wavelength emitted when a first drive current is passed through the active layer, and a fourth wavelength emitted when a second drive current is passed through the active layer,
The third reflective layer may have different reflectances for the third wavelength and the fourth wavelength.
　前記第３反射層は、前記第３波長に対する反射率よりも、前記第４波長に対する反射率が高く、
　前記レーザ媒質は、前記第３波長に対しては前記第２波長を励起させず、前記第４波長に対しては前記第２波長を励起させてもよい。 The third reflective layer has a higher reflectance for the fourth wavelength than a reflectance for the third wavelength,
The laser medium may not excite the second wavelength with respect to the third wavelength, and may excite the second wavelength with respect to the fourth wavelength.
　前記第３反射層は、前記第３波長に対する反射率よりも、前記第４波長に対する反射率が低く、
　前記レーザ媒質は、前記第４波長に対しては前記第２波長を励起させず、前記第３波長に対しては前記第２波長を励起させてもよい。 The third reflective layer has a lower reflectance for the fourth wavelength than a reflectance for the third wavelength,
The laser medium may not excite the second wavelength with respect to the fourth wavelength, and may excite the second wavelength with respect to the third wavelength.
　前記第１駆動電流は、前記第２駆動電流よりも小さく、
　前記第３波長は、前記第４波長よりも短くてもよい。 the first drive current is smaller than the second drive current,
The third wavelength may be shorter than the fourth wavelength.
　前記積層半導体層は、それぞれ異なる前記第１波長の光を出射する複数の第１領域を有し、
　前記第３反射層は、前記複数の第１領域に対応して設けられ、前記第１波長に対してそれぞれ異なる反射率を有する複数の第２領域を有してもよい。 The laminated semiconductor layer has a plurality of first regions that each emit light of a different first wavelength,
The third reflective layer may be provided corresponding to the plurality of first regions, and may have a plurality of second regions each having a different reflectance with respect to the first wavelength.
　前記積層半導体層は、前記第３波長又は前記第４波長の光を出射する複数の第１領域を有し、
　前記第３反射層は、前記複数の第１領域に対応して設けられ、前記第３波長及び前記第４波長に対して互いに異なる反射率を持つ複数の第２領域を有してもよい。 The laminated semiconductor layer has a plurality of first regions that emit light of the third wavelength or the fourth wavelength,
The third reflective layer may be provided corresponding to the plurality of first regions, and may have a plurality of second regions having mutually different reflectances for the third wavelength and the fourth wavelength.
　前記積層半導体層は、前記第１波長の光を間欠的に出射してもよい。 The laminated semiconductor layer may intermittently emit light of the first wavelength.
　前記第２反射層及び前記第４反射層の間で前記第２波長の光を共振させる第２共振器をさらに備えてもよい。 It may further include a second resonator that causes the light of the second wavelength to resonate between the second reflective layer and the fourth reflective layer.
　前記第４反射層を有する可飽和吸収体をさらに備え、
　前記積層半導体層の光軸、前記レーザ媒質の光軸、前記可飽和吸収体の光軸は、一軸上に配置されてもよい。 further comprising a saturable absorber having the fourth reflective layer,
The optical axis of the laminated semiconductor layer, the optical axis of the laser medium, and the optical axis of the saturable absorber may be arranged on one axis.
　前記第２波長の光は、前記第１波長の光より大きいピークパワーを有してもよい。 The light at the second wavelength may have a larger peak power than the light at the first wavelength.
　前記第４反射層は、前記第２波長の、Ｑスイッチパルス波光を出射してもよい。 The fourth reflective layer may emit Q-switched pulse wave light of the second wavelength.
　また、本開示によれば、
　波長を切り替えて発光可能な光源装置と、
　受光部と、
　前記光源装置の発光信号が対象物で反射されて前記受光部で受光されたときに、前記発光信号と前記受光部の受光信号とに基づいて前記対象物までの距離を計測する距離計測部と、を備え、
　前記光源装置は、
　駆動条件に応じて変化する波長である第１波長の光を出射する活性層と、前記第１波長に対する第１反射層と、を有する積層半導体層と、
　前記積層半導体層の光出射面に対向する第１面に配置される第２波長に対する第２反射層と、
　前記第１面よりも光軸の後方側に配置される第２面に配置され、前記第１波長に対する第３反射層と、
　前記第２反射層及び前記第３反射層の間に配置されるレーザ媒質と、
　前記第２面に配置されるか、又は前記第２面より光軸の後方側に配置される、前記第２波長に対する第４反射層と、
　前記第１反射層及び前記第３反射層の間で前記第１波長の光を共振させる第１共振器と、
　前記第２反射層及び前記第４反射層の間で前記第２波長の光を共振させる第２共振器と、
を備え、
　前記積層半導体層の光軸及び前記レーザ媒質の光軸は、一軸上に配置される、
測距装置が提供される。 Further, according to the present disclosure,
A light source device that can emit light by switching wavelengths,
A light receiving section,
a distance measuring unit that measures the distance to the target object based on the light emission signal and the light reception signal of the light reception unit when the light emission signal of the light source device is reflected by the target object and received by the light reception unit; , comprising:
The light source device includes:
a laminated semiconductor layer having an active layer that emits light of a first wavelength that changes depending on driving conditions; and a first reflective layer for the first wavelength;
a second reflective layer for a second wavelength disposed on a first surface facing the light emitting surface of the laminated semiconductor layer;
a third reflective layer for the first wavelength, disposed on a second surface disposed on the rear side of the optical axis from the first surface;
a laser medium disposed between the second reflective layer and the third reflective layer;
a fourth reflective layer for the second wavelength, which is disposed on the second surface or on the rear side of the optical axis from the second surface;
a first resonator that causes light of the first wavelength to resonate between the first reflective layer and the third reflective layer;
a second resonator that causes light of the second wavelength to resonate between the second reflective layer and the fourth reflective layer;
Equipped with
The optical axis of the laminated semiconductor layer and the optical axis of the laser medium are arranged on one axis,
A ranging device is provided.
　前記対象物までの距離に応じて前記駆動条件を制御する駆動部を備えてもよい。 It may also include a drive unit that controls the drive conditions according to the distance to the target object.
　前記駆動部は、前記対象物の距離に応じて、前記光源装置から出射される前記発光信号のピークパワーを切替制御してもよい。 The driving unit may switch and control the peak power of the light emission signal emitted from the light source device according to the distance to the target object.
　また、本開示によれば、
　波長を切り替えて発光可能な光源装置の発光信号が対象物で反射されて受光部で受光されたときに、前記発光信号と前記受光部の受光信号とに基づいて対象物までの距離を計測し、
　前記光源装置は、
　駆動条件に応じて変化する波長である第１波長の光を出射する活性層と、前記第１波長に対する第１反射層と、を有する積層半導体層と、
　前記積層半導体層の光出射面に対向する第１面に配置される第２波長に対する第２反射層と、
　前記第１面よりも光軸の後方側に配置される第２面に配置され、前記第１波長に対する第３反射層と、
　前記第２反射層及び前記第３反射層の間に配置されるレーザ媒質と、
　前記第２面に配置されるか、又は前記第２面より光軸の後方側に配置される、前記第２波長に対する第４反射層と、
　前記第１反射層及び前記第３反射層の間で前記第１波長の光を共振させる第１共振器と、
　前記第２反射層及び前記第４反射層の間で前記第２波長の光を共振させる第２共振器と、を積層して形成され、
　前記積層半導体層の光軸及び前記レーザ媒質の光軸は、一軸上に配置される、
測距方法が提供される。 Further, according to the present disclosure,
When a light emitting signal from a light source device capable of emitting light by switching the wavelength is reflected by a target object and received by a light receiving section, the distance to the target object is measured based on the light emitting signal and the light receiving signal of the light receiving section. ,
The light source device includes:
a laminated semiconductor layer having an active layer that emits light of a first wavelength that changes depending on driving conditions; and a first reflective layer for the first wavelength;
a second reflective layer for a second wavelength disposed on a first surface facing the light emitting surface of the laminated semiconductor layer;
a third reflective layer for the first wavelength, disposed on a second surface disposed on the rear side of the optical axis from the first surface;
a laser medium disposed between the second reflective layer and the third reflective layer;
a fourth reflective layer for the second wavelength, disposed on the second surface or disposed on the rear side of the optical axis from the second surface;
a first resonator that causes light of the first wavelength to resonate between the first reflective layer and the third reflective layer;
a second resonator that resonates light of the second wavelength between the second reflective layer and the fourth reflective layer,
The optical axis of the laminated semiconductor layer and the optical axis of the laser medium are arranged on one axis,
A ranging method is provided.
第１の実施形態における光源装置の構成を示す概略図である。It is a schematic diagram showing the composition of the light source device in a 1st embodiment. 第１の実施形態における励起光源及び支持体の構成を示す概略図である。It is a schematic diagram showing the composition of an excitation light source and a support body in a 1st embodiment. 駆動電流により活性層が放出する第１波長が変化する様子を示す図である。FIG. 3 is a diagram showing how the first wavelength emitted by the active layer changes depending on the drive current. 温度により活性層が放出する第１波長が変化する様子を示す図である。FIG. 3 is a diagram showing how the first wavelength emitted by the active layer changes depending on the temperature. 第１波長により、第３反射層の反射率が変化する様子を示す図である。FIG. 6 is a diagram showing how the reflectance of the third reflective layer changes depending on the first wavelength. 図４Ａのグラフのうち、区間λa～λdを抜き出したグラフである。This is a graph in which the section λa to λd is extracted from the graph in FIG. 4A. 図４Ａのグラフのうち、区間λc～λfを抜き出したグラフである。This is a graph in which the section λc to λf is extracted from the graph in FIG. 4A. 励起光が第３反射層を透過する場合の、光源装置のレーザ動作を示す図である。It is a figure which shows the laser operation of a light source device when excitation light permeate|transmits a 3rd reflective layer. 励起光が第３反射層に反射される場合の、光源装置のレーザ動作を示す図である。It is a figure which shows the laser operation of a light source device when excitation light is reflected by a 3rd reflective layer. 第２の実施形態における光源装置の構成を示す概略図である。It is a schematic diagram showing the composition of the light source device in a 2nd embodiment. 第２の実施形態における光源装置の市松模様状の発光を示す図である。FIG. 7 is a diagram illustrating checkered pattern light emission of the light source device in the second embodiment. 第２の実施形態における光源装置のライン＆スペースパターンの発光を示す図である。FIG. 7 is a diagram showing light emission in a line and space pattern of a light source device in a second embodiment. 第３の実施形態における活性層に与えるパルス電流を示す図である。It is a figure showing the pulse current given to the active layer in a 3rd embodiment. 第３の実施形態における第１発振光Ｌ１の出力を示す図である。It is a figure showing the output of the 1st oscillation light L1 in a 3rd embodiment. 第２発振光Ｌ２の出力を示す図である。FIG. 3 is a diagram showing the output of second oscillation light L2. 第４の実施形態に係る光源装置の一実装例としての測距装置の構成例を示す図である。FIG. 12 is a diagram illustrating a configuration example of a distance measuring device as an example of implementation of a light source device according to a fourth embodiment. 被写体が測距装置から近距離にある場合の、光源装置のレーザ光の出射動作を示す図である。FIG. 6 is a diagram illustrating a laser beam emitting operation of a light source device when a subject is located at a short distance from a distance measuring device. 被写体が測距装置から遠距離にある場合の、光源装置のレーザ光の出射動作を示す図である。FIG. 6 is a diagram illustrating a laser beam emitting operation of a light source device when a subject is far away from a distance measuring device. 車両制御システムの概略的な構成の一例を示すブロック図である。FIG. 1 is a block diagram showing an example of a schematic configuration of a vehicle control system. 車外情報検出部及び撮像部の設置位置の一例を示す説明図である。FIG. 2 is an explanatory diagram showing an example of installation positions of an outside-vehicle information detection section and an imaging section.
　以下、図面を参照して、光源装置、測距装置、及び測距方法の実施形態について説明する。以下では、光源装置、測距装置、及び測距方法の主要な構成部分を中心に説明するが、光源装置、測距装置、及び測距方法には、図示又は説明されていない構成部分や機能が存在しうる。以下の説明は、図示又は説明されていない構成部分や機能を除外するものではない。 Hereinafter, embodiments of a light source device, a distance measuring device, and a distance measuring method will be described with reference to the drawings. The main components of the light source device, distance measuring device, and distance measuring method will be mainly explained below. can exist. The following description does not exclude components or features not shown or described.
（第１の実施形態）
　図１は、第１の実施形態による光源装置１の構成を示す概略図である。光源装置１は、例えば、医療用レーザ、又は後述の測距装置用光源として用いられる。光源装置１は、励起光源（積層半導体層）２と、レーザ媒質３を備える。また、光源装置１は可飽和吸収体４を備えていてもよい。 (First embodiment)
FIG. 1 is a schematic diagram showing the configuration of a light source device 1 according to the first embodiment. The light source device 1 is used, for example, as a medical laser or a light source for a distance measuring device, which will be described later. The light source device 1 includes an excitation light source (laminated semiconductor layer) 2 and a laser medium 3. Further, the light source device 1 may include a saturable absorber 4.
　励起光源２は、レーザ媒質３を励起させるための第１発振光Ｌ１を出射する。励起光源２は、基板２１、第５反射層Ｒ５、クラッド層２２、活性層２３、クラッド層２４、及び第１反射層Ｒ１を順に積層した、積層構造の半導体層で構成されている。 The excitation light source 2 emits first oscillation light L1 for exciting the laser medium 3. The excitation light source 2 is composed of semiconductor layers having a laminated structure in which a substrate 21, a fifth reflective layer R5, a cladding layer 22, an active layer 23, a cladding layer 24, and a first reflective layer R1 are laminated in this order.
　図１の励起光源２は、基板２１から連続波（ＣＷ：Continuous Wave）の第１発振光Ｌ１を放出するボトムエミッション型の構成を示しているが、第１反射層Ｒ１側からＣＷ励起光を放出するトップエミッション型の構成も取りうる。 The excitation light source 2 in FIG. 1 has a bottom emission type configuration in which the first continuous wave (CW) oscillation light L1 is emitted from the substrate 21, but the CW excitation light is emitted from the first reflective layer R1 side. A top-emission type configuration is also possible.
　基板２１は、例えばｎ－ＧａＡｓ基板である。ｎ－ＧａＡｓ基板は、励起光源２の励起波長である第１発振光Ｌ１を一定の割合で吸収するため、吸収を抑えるために極力薄くするのが望ましい。その一方で、例えば他の部材と接合する際の機械的強度を維持できる程度の厚みを持たせるのが望ましい。 The substrate 21 is, for example, an n-GaAs substrate. Since the n-GaAs substrate absorbs the first oscillation light L1, which is the excitation wavelength of the excitation light source 2, at a constant rate, it is desirable to make it as thin as possible in order to suppress absorption. On the other hand, it is desirable to have a thickness sufficient to maintain mechanical strength when joining, for example, to other members.
　活性層２３は、第１発振光Ｌ１の面発光を行う。クラッド層２２、２４は、例えばＡｌＧａＡｓクラッド層である。第１反射層Ｒ１は、第１発振光Ｌ１を反射させる。第５反射層Ｒ５は、第１発振光Ｌ１に対して一定の透過率を有する。第１反射層Ｒ１と第５反射層Ｒ５には、例えば、電気伝導が可能な半導体分布反射層（ＤＢＲ：Distributed Bragg Reflector）が用いられる。図１では不図示の電極から、第１反射層Ｒ１と第５反射層Ｒ５を介して外部から電流（駆動電流）が注入され、活性層２３内の量子井戸で再結合と発光が生じて、第１発振光Ｌ１の発光が行われる。 The active layer 23 performs surface emission of the first oscillation light L1. The cladding layers 22 and 24 are, for example, AlGaAs cladding layers. The first reflective layer R1 reflects the first oscillation light L1. The fifth reflective layer R5 has a constant transmittance with respect to the first oscillation light L1. For the first reflective layer R1 and the fifth reflective layer R5, for example, a semiconductor distributed reflector (DBR) capable of electrical conduction is used. In FIG. 1, a current (drive current) is injected from the outside from an electrode (not shown) through the first reflective layer R1 and the fifth reflective layer R5, and recombination and light emission occur in the quantum well in the active layer 23. The first oscillation light L1 is emitted.
　図２は、第１の実施形態における励起光源２の支持構造を示す断面図である。図２では省略しているが、図２の基板２１の上に、図１に示したレーザ媒質３が配置され、さらにその上に可飽和吸収体４が配置されることもある。 FIG. 2 is a cross-sectional view showing the support structure of the excitation light source 2 in the first embodiment. Although not shown in FIG. 2, the laser medium 3 shown in FIG. 1 is arranged on the substrate 21 in FIG. 2, and the saturable absorber 4 may be further arranged thereon.
　励起光源２は、図１に示した積層構造に加えて、ｎ型コンタクト層２５を有する。コンタクト層２５は、基板２１と第５反射層Ｒ５の間に積層されている。コンタクト層２５は、第５反射層Ｒ５、クラッド層２２、活性層２３、クラッド層２４、及び第１反射層Ｒ１の側壁を覆う導電層５８と導通している。導電層５８はｎ型金属層であり、この導電層５８の周囲には絶縁層５９ａ、５９ｂが配置されている。 The excitation light source 2 has an n-type contact layer 25 in addition to the stacked structure shown in FIG. The contact layer 25 is laminated between the substrate 21 and the fifth reflective layer R5. The contact layer 25 is electrically connected to the fifth reflective layer R5, the cladding layer 22, the active layer 23, the cladding layer 24, and the conductive layer 58 that covers the sidewalls of the first reflective layer R1. The conductive layer 58 is an n-type metal layer, and insulating layers 59a and 59b are arranged around the conductive layer 58.
　支持体５は、マウント部材５１の上にサブマウント部材５２を配置した構成を有する。サブマウント部材５２の上には、配線層５３ａ、５３ｂが互いに分離して配置されている。配線層５３ａは、第１反射層Ｒ１に積層された導電層５７と、半田層５６ａ、５６ｂを介して導通している。導電層５７はｐ型金属層である。 The support body 5 has a configuration in which a submount member 52 is arranged on a mount member 51. On the submount member 52, wiring layers 53a and 53b are arranged separately from each other. The wiring layer 53a is electrically connected to the conductive layer 57 stacked on the first reflective layer R1 via solder layers 56a and 56b. Conductive layer 57 is a p-type metal layer.
　マウント部材５１には、ピン５４ａ、５４ｂが取り付けられている。ピン５４ａ、５４ｂは、マウント部材５１を貫通するように配置され、不図示の駆動電源に接続されている。ピン５４ａ、５４ｂは、ワイヤ５５ａ、５５ｂによって、配線層５３ａ、５３ｂとそれぞれ接続されている。ピン５４ａの印加電圧は、ワイヤ５５ａ、配線層５３ａ、半田層５６ａ、及び導電層５７を介して、第１反射層Ｒ１に印加される。また、ピン５４ｂの印加電圧は、ワイヤ５５ｂ、配線層５３ｂ、半田層５６ｂ、及び導電層５８を介して、コンタクト層２５に印加される。 Pins 54a and 54b are attached to the mount member 51. The pins 54a and 54b are arranged to penetrate the mount member 51 and are connected to a drive power source (not shown). The pins 54a and 54b are connected to the wiring layers 53a and 53b by wires 55a and 55b, respectively. The voltage applied to the pin 54a is applied to the first reflective layer R1 via the wire 55a, the wiring layer 53a, the solder layer 56a, and the conductive layer 57. Further, the voltage applied to the pin 54b is applied to the contact layer 25 via the wire 55b, the wiring layer 53b, the solder layer 56b, and the conductive layer 58.
　これにより、活性層２３には、第１反射層Ｒ１に印加された電圧と、コンタクト層２５に印加された電圧との電位差に応じた駆動電流が注入される。 As a result, a driving current is injected into the active layer 23 according to the potential difference between the voltage applied to the first reflective layer R1 and the voltage applied to the contact layer 25.
　本明細書においては、第１発振光Ｌ１の波長を第１波長λ１と呼ぶ。第１波長λ１は、励起光源２内の半導体材料によって変化する。また第１波長λ１は、駆動条件に応じても変化する。駆動条件は、例えば活性層２３の温度、又は上述の駆動電流に依存する。 In this specification, the wavelength of the first oscillation light L1 is referred to as a first wavelength λ1. The first wavelength λ1 varies depending on the semiconductor material within the excitation light source 2. The first wavelength λ1 also changes depending on driving conditions. The driving conditions depend on, for example, the temperature of the active layer 23 or the above-mentioned driving current.
　図３Ａは、駆動電流により、活性層２３が出射する第１波長λ１が変化する様子を示す図である。横軸が駆動電流の電流量を示し、縦軸は第１発振光Ｌ１の波長を示す。図３Ａに示すように、活性層２３は駆動電流が大きいほど、より長い波長の第１発振光Ｌ１を出射する。 FIG. 3A is a diagram showing how the first wavelength λ1 emitted from the active layer 23 changes depending on the drive current. The horizontal axis indicates the amount of drive current, and the vertical axis indicates the wavelength of the first oscillation light L1. As shown in FIG. 3A, the active layer 23 emits the first oscillation light L1 having a longer wavelength as the driving current increases.
　本明細書では、第１駆動電流Ｉ１を流すときに出射される第３波長λ３と、第２駆動電流Ｉ２を流すときに出射される第４波長λ４とを含めて第１波長λ１と呼ぶ。なお、第１駆動電流Ｉ１は、第２駆動電流Ｉ２よりも小さいものとする。この場合、第３波長λ３は、第４波長λ４よりも短くなる。 In this specification, the third wavelength λ3 emitted when the first drive current I1 is applied and the fourth wavelength λ4 emitted when the second drive current I2 is applied are collectively referred to as the first wavelength λ1. Note that the first drive current I1 is assumed to be smaller than the second drive current I2. In this case, the third wavelength λ3 is shorter than the fourth wavelength λ4.
　図３Ｂは、温度により、活性層２３が出射する第１波長λ１が変化する様子を示す図である。横軸は活性層２３の温度を示し、縦軸は波長の大きさを示す。図３Ｂに示すように、活性層２３は温度が高いほど、より長い波長の第１発振光Ｌ１を出射する。本明細書では、第１温度Ｔ１のときに出射される第３波長λ３’と、第２温度Ｔ２のときに出射される第４波長λ４’とを含めて第１波長λ１と呼ぶ。 FIG. 3B is a diagram showing how the first wavelength λ1 emitted from the active layer 23 changes depending on the temperature. The horizontal axis represents the temperature of the active layer 23, and the vertical axis represents the wavelength. As shown in FIG. 3B, the higher the temperature of the active layer 23, the longer the wavelength of the first oscillation light L1 is emitted. In this specification, the third wavelength λ3' emitted at the first temperature T1 and the fourth wavelength λ4' emitted at the second temperature T2 are collectively referred to as a first wavelength λ1.
　図３Ａ及び図３Ｂに示すように、活性層２３は、駆動電流又は温度を制御することにより、それぞれ波長が異なる少なくとも２種類の第１発振光Ｌ１を切り替えて出射することができる。 As shown in FIGS. 3A and 3B, the active layer 23 can switch and emit at least two types of first oscillation light L1, each having a different wavelength, by controlling the drive current or temperature.
　第５反射層Ｒ５は、例えば基板２１上に配置される。例えば、第５反射層Ｒ５は、ｎ型ドーパント（例えばシリコン）を添加したＡｌｚ１Ｇａ１－ｚ１Ａｓ／Ａｌｚ２Ｇａ１－ｚ２Ａｓ（０≦ｚ１≦ｚ２≦１）からなる多層反射膜を有する。第５反射層Ｒ５は、ｎ－ＤＢＲとも呼ばれる。 The fifth reflective layer R5 is arranged on the substrate 21, for example. For example, the fifth reflective layer R5 has a multilayer reflective film made of Alz1Ga1-z1As/Alz2Ga1-z2As (0≦z1≦z2≦1) doped with an n-type dopant (for example, silicon). The fifth reflective layer R5 is also called n-DBR.
　活性層２３は、例えば、Ａｌｘ１Ｉｎｙ１Ｇａ１－ｘ１－ｙ１Ａｓ層とＡｌｘ３Ｉｎｙ３Ｇａ１－ｘ３－ｙ３Ａｓ層を積層した多重量子井戸層を有する。 The active layer 23 has, for example, a multiple quantum well layer in which an Alx1Iny1Ga1-x1-y1As layer and an Alx3Iny3Ga1-x3-y3As layer are laminated.
　第１反射層Ｒ１は、例えば、ｐ型ドーパント（例えば炭素）を添加したＡｌｚ３Ｇａ１－ｚ３Ａｓ／Ａｌｚ４Ｇａ１－ｚ４Ａｓ（０≦ｚ３≦ｚ４≦１）からなる多重反射膜を有する。第１反射層Ｒ１は、ｐ－ＤＢＲとも呼ばれる。 The first reflective layer R1 has a multi-reflective film made of, for example, Alz3Ga1-z3As/Alz4Ga1-z4As (0≦z3≦z4≦1) doped with a p-type dopant (for example, carbon). The first reflective layer R1 is also called p-DBR.
　励起光共振器としての励起光源２内の各半導体層（第５反射層Ｒ５、クラッド層２２、活性層２３、クラッド層２４、及び第１反射層Ｒ１）は、ＭＯＣＶＤ（Metal Organic Chemical Vapor Deposition：有機金属気相成長）法、ＭＢＥ（Molecular Beam Epitaxity：分子線エピタキシ法）等の結晶成長法を用いて形成することができる。そして、結晶成長後に、素子分離のためのメサエッチング、絶縁膜の形成、及び電極膜の蒸着等のプロセスを経て、駆動電流注入による駆動が可能になる。 Each semiconductor layer (fifth reflective layer R5, cladding layer 22, active layer 23, cladding layer 24, and first reflective layer R1) in the excitation light source 2 as an excitation light resonator is formed by MOCVD (Metal Organic Chemical Vapor Deposition: It can be formed using a crystal growth method such as metalorganic vapor phase epitaxy (MBE) or molecular beam epitaxy (MBE). After the crystal growth, processes such as mesa etching for element isolation, formation of an insulating film, and vapor deposition of an electrode film are performed to enable driving by injection of a driving current.
　励起光源２は、レーザ媒質３を励起可能な励起光を出射する部材であればよく、必ずしも半導体レーザ素子である必要はない。また、励起光源２に用いられる材料は、結晶質材料でもよいしセラミックなどの非晶質材料でもよい。さらに、励起光源２は、第１発振光Ｌ１をレーザ媒質３に入射させることができればよく、レンズ等の光学系を備えていなくてもよい。 The excitation light source 2 may be any member that emits excitation light that can excite the laser medium 3, and does not necessarily need to be a semiconductor laser element. Further, the material used for the excitation light source 2 may be a crystalline material or an amorphous material such as ceramic. Furthermore, the excitation light source 2 only needs to be able to make the first oscillation light L1 enter the laser medium 3, and does not need to include an optical system such as a lens.
　励起光源２の基板２１の第５反射層Ｒ５とは反対側、即ち光軸の後方側には、レーザ媒質３が配置されている。レーザ媒質３は、第２反射層Ｒ２及び第３反射層Ｒ３を有する。 A laser medium 3 is arranged on the opposite side of the substrate 21 of the excitation light source 2 from the fifth reflective layer R5, that is, on the rear side of the optical axis. The laser medium 3 has a second reflective layer R2 and a third reflective layer R3.
　第２反射層Ｒ２は、励起光源２の光出射面に対向する第１面Ｓ１に配置されている。第３反射層Ｒ３は、第１面Ｓ１よりも光軸の後方側の第２面Ｓ２に配置されている。レーザ媒質３は、第２反射層Ｒ２及び第３反射層Ｒ３の間に配置されている。 The second reflective layer R2 is arranged on the first surface S1 facing the light exit surface of the excitation light source 2. The third reflective layer R3 is arranged on the second surface S2 on the rear side of the optical axis than the first surface S1. The laser medium 3 is arranged between the second reflective layer R2 and the third reflective layer R3.
　レーザ媒質３は、第１発振光Ｌ１により励起されたときに第２発振光Ｌ２を出射する。レーザ媒質３は、例えば、可飽和吸収体４と対向するように配置される。また、励起光源２の光軸と、レーザ媒質３の光軸は、一軸上に配列されている。なお、第２発振光Ｌ２の波長を、本明細書では第２波長λ２と呼ぶ。 The laser medium 3 emits the second oscillation light L2 when excited by the first oscillation light L1. For example, the laser medium 3 is arranged to face the saturable absorber 4. Further, the optical axis of the excitation light source 2 and the optical axis of the laser medium 3 are arranged on one axis. Note that the wavelength of the second oscillation light L2 is referred to as a second wavelength λ2 in this specification.
　レーザ媒質３は、例えば、Ｙｂ（イットリビウム）をドープしたＹＡＧ（イットリウム・アルミニウム・ガーネット）結晶Ｙｂ：ＹＡＧを含む。 The laser medium 3 includes, for example, YAG (yttrium aluminum garnet) crystal Yb:YAG doped with Yb (yttribium).
　レーザ媒質３は、Ｙｂ：ＹＡＧに限らず、例えば、レーザ媒質３として、Ｎｄ：ＹＡＧ、Ｎｄ：ＹＶＯ４、Ｎｄ：ＹＬＦ、Ｎｄ：ｇｌａｓｓ、Ｙｂ：ＹＡＧ、Ｙｂ：ＹＬＦ、Ｙｂ：ＦＡＰ、Ｙｂ：ＳＦＡＰ、Ｙｂ：ＹＶＯ、Ｙｂ：ｇｌａｓｓ、Ｙｂ：ＫＹＷ、Ｙｂ：ＢＣＢＦ、Ｙｂ：ＹＣＯＢ、Ｙｂ：ＧｄＣＯＢ、Ｙｂ：ＹＡＢの少なくともいずれかの材料を使うことができる。 The laser medium 3 is not limited to Yb:YAG, and examples of the laser medium 3 include Nd:YAG, Nd:YVO4, Nd:YLF, Nd:glass, Yb:YAG, Yb:YLF, Yb:FAP, Yb:SFAP. , Yb:YVO, Yb:glass, Yb:KYW, Yb:BCBF, Yb:YCOB, Yb:GdCOB, and Yb:YAB.
　また、レーザ媒質３は、４準位系の固体レーザ媒質であってもよいし、３準位系の固体レーザ媒質であってもよい。ただし、それぞれの結晶によって、適切な励起波長は異なるので、第１波長λ１に応じて、レーザ媒質３の材料を選択する必要がある。 Furthermore, the laser medium 3 may be a four-level solid-state laser medium or a three-level solid-state laser medium. However, since the appropriate excitation wavelength differs depending on each crystal, it is necessary to select the material of the laser medium 3 according to the first wavelength λ1.
　レーザ媒質３においてレーザ出力側（第３反射層Ｒ３）の面には励起光を反射する反射層（例えば、誘電体多層膜）が設けられてもよい。 A reflective layer (for example, a dielectric multilayer film) that reflects excitation light may be provided on the surface of the laser medium 3 on the laser output side (third reflective layer R3).
　一対の第２反射層Ｒ２及び第３反射層Ｒ３のうち、励起光源２側に配置される第２反射層Ｒ２は、例えば、励起光源２から出射された第１波長λ１の第１発振光Ｌ１を透過させ、かつ、レーザ媒質３から出射された第２波長λ２の第２発振光Ｌ２を所定の反射率で反射する。 Of the pair of second reflective layer R2 and third reflective layer R3, the second reflective layer R2 disposed on the excitation light source 2 side is, for example, the first oscillation light L1 of the first wavelength λ1 emitted from the excitation light source 2. and reflects the second oscillation light L2 of the second wavelength λ2 emitted from the laser medium 3 with a predetermined reflectance.
　一方、励起光源２の反対側に備えられる第３反射層Ｒ３は、例えば、レーザ媒質３から出射された第２波長λ２の第２発振光Ｌ２を透過する。また第３反射層Ｒ３は、上述の駆動電流によって、それぞれ波長が異なる少なくとも２種類の第１発振光Ｌ１に対し、それぞれ異なる反射率を有する。 On the other hand, the third reflective layer R3 provided on the opposite side of the excitation light source 2 transmits, for example, the second oscillation light L2 of the second wavelength λ2 emitted from the laser medium 3. Further, the third reflective layer R3 has different reflectances for at least two types of first oscillation light L1 having different wavelengths depending on the above-described drive current.
　図４Ａは、第１発振光Ｌ１の波長により、第３反射層Ｒ３の反射率Ｒが変化する様子を示す図である。横軸が第１発振光Ｌ１の波長を示し、縦軸は第３反射層Ｒ３の反射率Ｒを示す。図４Ａでは、反射率Ｒを、最大で略１００％としている。 FIG. 4A is a diagram showing how the reflectance R of the third reflective layer R3 changes depending on the wavelength of the first oscillation light L1. The horizontal axis indicates the wavelength of the first oscillation light L1, and the vertical axis indicates the reflectance R of the third reflective layer R3. In FIG. 4A, the reflectance R is approximately 100% at maximum.
　図４Ａでは、波長λa＜λb＜λc＜λd＜λe＜λfの順に波長が長くなるものとしている。波長λa～λbでは反射率Ｒは一定である。波長λb～λcでは反射率Ｒは増大する。波長λc～λdでは反射率Ｒは一定であり、このときの反射率Ｒが最大である。波長λd～λeでは反射率Ｒは減少する。波長λe～波長fでは反射率Ｒは一定であり、このときの反射率Ｒが最低である。 In FIG. 4A, the wavelengths are assumed to increase in the order of wavelength λa<λb<λc<λd<λe<λf. The reflectance R is constant between wavelengths λa and λb. The reflectance R increases at wavelengths λb to λc. The reflectance R is constant between wavelengths λc to λd, and the reflectance R at this time is the maximum. The reflectance R decreases at wavelengths λd to λe. The reflectance R is constant from the wavelength λe to the wavelength f, and the reflectance R at this time is the lowest.
　図４Ｂは、図４Ａのグラフのうち、波長λa～λdの区間を拡大した図である。図４Ｂに示すように、上述の第３波長λ３は、波長λa～λbの間にあってもよい。また、第４波長λ４は、波長λc～λdの間にあってもよい。この場合、第３反射層Ｒ３は、第３波長λ３に対して反射率Ｒaを有する。また、第４波長λ４に対しては、反射率Ｒaよりも高い反射率Ｒbを有する。 FIG. 4B is an enlarged view of the wavelength λa to λd section of the graph of FIG. 4A. As shown in FIG. 4B, the third wavelength λ3 described above may be between the wavelengths λa and λb. Further, the fourth wavelength λ4 may be between the wavelengths λc to λd. In this case, the third reflective layer R3 has a reflectance Ra for the third wavelength λ3. Further, for the fourth wavelength λ4, it has a reflectance Rb higher than the reflectance Ra.
　反射率Ｒbは、略１００％であってもよい。この場合、第３反射層Ｒ３は、第１発振光Ｌ１が第４波長λ４であるときに全反射させる。一方、第１発振光Ｌ１が第３波長λ３のときには、ある程度の光を透過させる。 The reflectance Rb may be approximately 100%. In this case, the third reflective layer R3 totally reflects the first oscillation light L1 at the fourth wavelength λ4. On the other hand, when the first oscillation light L1 has the third wavelength λ3, a certain amount of light is transmitted.
　図４Ｃは、図４Ａのグラフのうち、波長λc～λfの区間を拡大した図である。図４Ｃに示すように、上述の第３波長λ３は、波長λc～λdの間にあってもよい。また、第４波長λ４は、波長λe～λfの間にあってもよい。この場合、第３反射層Ｒ３は、第３波長λ３に対して反射率Ｒbを有する。また、第４波長λ４に対しては、反射率Ｒbよりも低い反射率Ｒcを有する。 FIG. 4C is an enlarged view of the wavelength λc to λf section of the graph of FIG. 4A. As shown in FIG. 4C, the third wavelength λ3 described above may be between wavelengths λc and λd. Furthermore, the fourth wavelength λ4 may be between wavelengths λe and λf. In this case, the third reflective layer R3 has a reflectance Rb for the third wavelength λ3. Furthermore, for the fourth wavelength λ4, it has a reflectance Rc lower than the reflectance Rb.
　図４Ｂと同様、反射率Ｒbが略１００％であるとき、第３反射層Ｒ３は、第３波長λ３の第１発振光Ｌ１を全反射させる。一方、第４波長λ４の第１発振光Ｌ１をある程度透過させる。 Similarly to FIG. 4B, when the reflectance Rb is approximately 100%, the third reflective layer R3 totally reflects the first oscillation light L1 having the third wavelength λ3. On the other hand, the first oscillation light L1 having the fourth wavelength λ4 is transmitted to some extent.
　図１の第２反射層Ｒ２及び第３反射層Ｒ３には、例えば、高屈折率材料からなる層と低屈折率材料からなる層とが交互に積層された誘電体多層膜が用いられる。誘電体多層膜の厚さは、例えば第１発振光Ｌ１の波長の４分の１であり、総数は数層から数百層である。誘電体多層膜の高屈折率材料としてはＡｌ２Ｏ３、ＨｆＯ２、ＴｉＯ２、ＺｒＯ２、Ｔａ２Ｏ５、Ｎｂ２Ｏ５、ＺｎＯ２、１．６～２．５の屈折率を有する材料が用いられ、低屈折率材料としては、ＳｉＯ２、Ａｌ２Ｏ３、及びＭｇＦ２等の１．２～１．６の屈折率を有する材料が用いられる。誘電体多層膜を形成する方法は、例えば、化学気相成長（ＣＶＤ）法、反応性スパッタ法、ＲＡＳ法（Radical Assisted Sputtering）、又は真空蒸着法、イオンアシスト蒸着法である。また、このような反射膜が光学フィルタの両方の主面をなすように形成されてもよい。第２反射層Ｒ２及び第３反射層Ｒ３の層構造や材料、成膜方法は、上記の例に限定されない。 For the second reflective layer R2 and the third reflective layer R3 in FIG. 1, for example, a dielectric multilayer film in which layers made of a high refractive index material and layers made of a low refractive index material are alternately laminated is used. The thickness of the dielectric multilayer film is, for example, one quarter of the wavelength of the first oscillation light L1, and the total number of layers is from several to several hundred layers. High refractive index materials for the dielectric multilayer film include Al2O3, HfO2, TiO2, ZrO2, Ta2O5, Nb2O5, ZnO2, and materials with a refractive index of 1.6 to 2.5, and low refractive index materials include SiO2. A material having a refractive index of 1.2 to 1.6 is used, such as , Al2O3, and MgF2. A method for forming the dielectric multilayer film is, for example, a chemical vapor deposition (CVD) method, a reactive sputtering method, a RAS method (Radical Assisted Sputtering), a vacuum deposition method, or an ion-assisted deposition method. Further, such reflective films may be formed on both main surfaces of the optical filter. The layer structure, material, and film-forming method of the second reflective layer R2 and the third reflective layer R3 are not limited to the above examples.
　励起光源２、及びレーザ媒質３は、第１共振器１１を構成する。第１共振器１１の内部には、３つの反射層（第１反射層Ｒ１、第５反射層Ｒ５、及び第３反射層Ｒ３）が設けられる。このため、第１共振器１１は、結合共振器（Coupled Cavity）構造である。 The excitation light source 2 and the laser medium 3 constitute a first resonator 11. Three reflective layers (first reflective layer R1, fifth reflective layer R5, and third reflective layer R3) are provided inside the first resonator 11. Therefore, the first resonator 11 has a coupled cavity structure.
　図１の光源装置１は、レーザ媒質３の第３反射層Ｒ３に対向するように配置される可飽和吸収体４を備えていてもよい。可飽和吸収体４は、第４反射層Ｒ４を有する。可飽和吸収体４の光軸は、励起光源２の光軸及びレーザ媒質３の光軸と、一軸上に配列されている。 The light source device 1 in FIG. 1 may include a saturable absorber 4 arranged to face the third reflective layer R3 of the laser medium 3. The saturable absorber 4 has a fourth reflective layer R4. The optical axis of the saturable absorber 4 is aligned on one axis with the optical axis of the excitation light source 2 and the optical axis of the laser medium 3.
　可飽和吸収体４は、例えば、Ｃｒ：ＹＡＧによって構成され、所定の波長の光を吸収し、光吸収の飽和により光吸収率が小さくなる性質を有する部材である。可飽和吸収体４は、例えば第２発振光Ｌ２を吸収し、第１発振光Ｌ１を透過する。 The saturable absorber 4 is made of, for example, Cr:YAG, and is a member that absorbs light of a predetermined wavelength and has the property that the light absorption rate decreases due to saturation of light absorption. The saturable absorber 4 absorbs, for example, the second oscillation light L2 and transmits the first oscillation light L1.
　これにより、可飽和吸収体４は、第２発振光Ｌ２に対する受動Ｑスイッチとして機能する。即ち、光源装置１は、第２波長λ２の光を出力する場合においては、受動Ｑスイッチパルスレーザ装置となる。 Thereby, the saturable absorber 4 functions as a passive Q switch for the second oscillation light L2. That is, the light source device 1 becomes a passive Q-switched pulse laser device when outputting light of the second wavelength λ2.
　例えば、可飽和吸収体４に、レーザ媒質３から出射された第２発振光Ｌ２が入射すると、その第２発振光Ｌ２を吸収し、その吸収度合が高まるに伴い、可飽和吸収体４の透過率が増加していく。その後、励起準位の電子密度が増大して励起準位が満たされた場合に、可飽和吸収体４が透明化して、光共振器のＱ値が高まり、レーザ発振が生じる。 For example, when the second oscillation light L2 emitted from the laser medium 3 enters the saturable absorber 4, the second oscillation light L2 is absorbed, and as the degree of absorption increases, the saturable absorber 4 transmits the second oscillation light L2. rate is increasing. Thereafter, when the electron density of the excited level increases and the excited level is filled, the saturable absorber 4 becomes transparent, the Q value of the optical resonator increases, and laser oscillation occurs.
　第４反射層Ｒ４はアウトプットカプラの機能を持つ部分反射層である。第４反射層Ｒ４は、第２面Ｓ２よりも光軸の後方側に配置されている。具体的には、可飽和吸収体４の光出射面に沿って配置される。なお、上述したように、可飽和吸収体４を持たない光源装置１もありうる。光源装置１が可飽和吸収体４を持たない場合、第４反射層Ｒ４を第２面Ｓ２に配置してもよい。この場合、第４反射層Ｒ４からは、連続波である第２発振光Ｌ２が出射されるが、そのピークパワーは、可飽和吸収体４から出射されるＱスイッチ光よりも小さくなる。 The fourth reflective layer R4 is a partial reflective layer that functions as an output coupler. The fourth reflective layer R4 is arranged on the rear side of the optical axis than the second surface S2. Specifically, it is arranged along the light exit surface of the saturable absorber 4. Note that, as described above, there may be a light source device 1 that does not have the saturable absorber 4. When the light source device 1 does not have the saturable absorber 4, the fourth reflective layer R4 may be arranged on the second surface S2. In this case, the second oscillation light L2, which is a continuous wave, is emitted from the fourth reflective layer R4, but its peak power is smaller than that of the Q-switched light emitted from the saturable absorber 4.
　光源装置１内の、励起光源２、レーザ媒質３、及び可飽和吸収体４は、それぞれ一体に接合されていてもよい。また、励起光源２とレーザ媒質３の間、又はレーザ媒質３と可飽和吸収体４の間に、スペーサ、偏光制御素子又は排熱部材等が配置されていてもよい。 The excitation light source 2, laser medium 3, and saturable absorber 4 in the light source device 1 may be joined together. Furthermore, a spacer, a polarization control element, a heat exhaust member, or the like may be arranged between the excitation light source 2 and the laser medium 3 or between the laser medium 3 and the saturable absorber 4.
　受動Ｑスイッチパルスレーザ装置は、例えば測距装置用の発光装置として用いられる。測距においては、例えば受動Ｑスイッチパルスレーザ装置が対象の物体にパルス状の光を照射し、物体から反射された光を、測距装置で受光することによって、物体との距離を測定する。 A passive Q-switched pulse laser device is used, for example, as a light emitting device for a distance measuring device. In distance measurement, for example, a passive Q-switched pulse laser device irradiates a target object with pulsed light, and a distance measuring device receives the light reflected from the object, thereby measuring the distance to the object.
　測距装置において、受動Ｑスイッチパルスレーザ装置から出射されたパルス状の光は、遠距離にある物体に照射する際には好適である。一方、近距離にある物体に照射する場合、レーザ安全上問題となる場合がある。測距対象の物体が近距離にある場合、遠距離の場合よりもより低いピークパワーの光を照射することがレーザ安全上望ましい。 In a distance measuring device, the pulsed light emitted from the passive Q-switched pulse laser device is suitable for irradiating an object at a long distance. On the other hand, when irradiating an object at a short distance, there may be a problem in terms of laser safety. When the object to be measured is at a short distance, it is desirable for laser safety to irradiate light with a lower peak power than when the object is at a long distance.
　このように、測距装置では、測距を行う物体までの距離によって、レーザ光のピークパワーを切り替えるのが望ましいが、既存の受動Ｑスイッチパルスレーザ装置は、ピークパワーの切替が容易ではない。以下に説明する本実施形態による光源装置１は、出射するレーザ光のピークパワーを切り替えることができることを特徴とする。 As described above, in a distance measuring device, it is desirable to switch the peak power of the laser beam depending on the distance to the object to be measured, but with existing passive Q-switched pulse laser devices, switching the peak power is not easy. A light source device 1 according to the present embodiment described below is characterized in that the peak power of the emitted laser light can be switched.
　図５Ａ及び図５Ｂは、本実施形態による光源装置１の動作を説明する図である。励起光源２の不図示の電極を介して駆動電流を活性層２３に注入することで、活性層２３から第１発振光Ｌ１の面発光が行われる。 5A and 5B are diagrams explaining the operation of the light source device 1 according to this embodiment. By injecting a drive current into the active layer 23 through an unillustrated electrode of the excitation light source 2, surface emission of the first oscillation light L1 is performed from the active layer 23.
　活性層２３に注入する駆動電流又は温度を制御することにより、図４Ｂに示す波長λa～λbの間の第３波長λ３の第１発振光Ｌ１を活性層２３から出射させることができる。この場合、第１発振光Ｌ１は第３反射層Ｒ３を透過する。よって、レーザ媒質３は、第１発振光Ｌ１を十分に吸収することができないことから、第２発振光Ｌ２を励起させることができない。 By controlling the drive current or temperature injected into the active layer 23, the first oscillation light L1 having the third wavelength λ3 between the wavelengths λa and λb shown in FIG. 4B can be emitted from the active layer 23. In this case, the first oscillation light L1 is transmitted through the third reflective layer R3. Therefore, since the laser medium 3 cannot sufficiently absorb the first oscillation light L1, it cannot excite the second oscillation light L2.
　上記の説明は、図４Ｃの波長λe～λfの間の第４波長λ４の第１発振光Ｌ１を活性層２３から出射させる場合についてもあてはまる。この場合も同様に、第１発振光Ｌ１は第３反射層Ｒ３を透過することから、レーザ媒質３は第２発振光Ｌ２を励起させない。 The above explanation also applies to the case where the first oscillation light L1 having the fourth wavelength λ4 between wavelengths λe to λf in FIG. 4C is emitted from the active layer 23. In this case as well, since the first oscillation light L1 passes through the third reflective layer R3, the laser medium 3 does not excite the second oscillation light L2.
　図５Ａは、第１発振光Ｌ１が第３反射層Ｒ３を透過する様子を破線で示している。この場合、第１共振器１１は、励起光源２の第１反射層Ｒ１と、レーザ媒質３の第３反射層Ｒ３との間で、第１発振光Ｌ１を共振させるとともに、第３反射層Ｒ３から第１発振光Ｌ１を出射する。第３反射層Ｒ３を透過した第１発振光Ｌ１は、可飽和吸収体４を透過し、さらに第４反射層Ｒ４を透過して、光源装置１から出射される。この場合、レーザ媒質３と可飽和吸収体４は、Ｑスイッチ動作を行わない。 FIG. 5A shows how the first oscillation light L1 passes through the third reflective layer R3 with a broken line. In this case, the first resonator 11 causes the first oscillation light L1 to resonate between the first reflective layer R1 of the excitation light source 2 and the third reflective layer R3 of the laser medium 3, and the third reflective layer R3 The first oscillation light L1 is emitted from the first oscillation light L1. The first oscillation light L1 that has passed through the third reflective layer R3 passes through the saturable absorber 4, and further passes through the fourth reflective layer R4, and is emitted from the light source device 1. In this case, the laser medium 3 and the saturable absorber 4 do not perform a Q-switch operation.
　図５Ａでは、光源装置１は連続波からなる第１発振光Ｌ１を出射するレーザ装置として機能する。この場合、例えば後述のＰＷＭ（Pulse Width Modulation）駆動により、ピークパワーを可変にすることができる。 In FIG. 5A, the light source device 1 functions as a laser device that emits first oscillation light L1 consisting of a continuous wave. In this case, the peak power can be made variable by, for example, PWM (Pulse Width Modulation) driving, which will be described later.
　一方、活性層２３に与える駆動電流又は温度を制御することにより、図４Ｂの波長λc～λdの間の第４波長λ４の第１発振光Ｌ１を活性層２３から出射させることができる。この場合、第３反射層Ｒ３は反射率Ｒbで第１発振光Ｌ１を反射する。 On the other hand, by controlling the drive current or temperature applied to the active layer 23, the first oscillation light L1 having the fourth wavelength λ4 between the wavelengths λc to λd in FIG. 4B can be emitted from the active layer 23. In this case, the third reflective layer R3 reflects the first oscillation light L1 with a reflectance Rb.
よって、第１共振器１１は、第１反射層Ｒ１と第３反射層Ｒ３の間で、第１発振光Ｌ１のパワーを内部に閉じ込める。これにより、レーザ媒質３は第１発振光Ｌ１を十分に吸収できることから、レーザ媒質３が励起され、第２波長の第２発振光Ｌ２が生成される。即ち、第１発振光Ｌ１は励起光として機能する。 Therefore, the first resonator 11 confines the power of the first oscillation light L1 between the first reflective layer R1 and the third reflective layer R3. Thereby, since the laser medium 3 can sufficiently absorb the first oscillation light L1, the laser medium 3 is excited and the second oscillation light L2 of the second wavelength is generated. That is, the first oscillation light L1 functions as excitation light.
　図４Ｃの波長λc～λdの間の第３波長λ３の第１発振光Ｌ１を活性層２３から出射させる場合についても同様である。この場合、第１発振光Ｌ１は第３反射層Ｒ３によって反射率Ｒbで反射され、第１共振器１１内に閉じ込められることにより、レーザ媒質３が第２発振光Ｌ２を励起する。 The same applies to the case where the first oscillation light L1 having the third wavelength λ3 between the wavelengths λc to λd in FIG. 4C is emitted from the active layer 23. In this case, the first oscillation light L1 is reflected by the third reflective layer R3 with a reflectance Rb and is confined within the first resonator 11, so that the laser medium 3 excites the second oscillation light L2.
　図５Ｂは、第１発振光Ｌ１が第３反射層Ｒ３で反射される様子を破線で示している。図５Ｂの場合、レーザ媒質３と可飽和吸収体４は、第２共振器１２を構成する。即ち、図５Ｂの光源装置１は、第１共振器１１と第２共振器１２を一体化した構造を備えている。また、第１共振器１１と第２共振器１２は、第２反射層Ｒ２と第３反射層Ｒ３間の部材（図５Ｂの例では、レーザ媒質３）を共有する構造である。 FIG. 5B shows how the first oscillation light L1 is reflected by the third reflective layer R3 with a broken line. In the case of FIG. 5B, the laser medium 3 and the saturable absorber 4 constitute the second resonator 12. That is, the light source device 1 in FIG. 5B has a structure in which the first resonator 11 and the second resonator 12 are integrated. Further, the first resonator 11 and the second resonator 12 have a structure in which a member (in the example of FIG. 5B, the laser medium 3) is shared between the second reflective layer R2 and the third reflective layer R3.
　第２共振器１２内の可飽和吸収体４により、レーザ媒質３から発光する最初の段階では、第２発振光Ｌ２は可飽和吸収体４に吸収されてしまい、可飽和吸収体４の出射面側の第４反射層Ｒ４からの光出射は起こらない。 At the initial stage of emitting light from the laser medium 3, the second oscillation light L2 is absorbed by the saturable absorber 4 in the second resonator 12, and the output surface of the saturable absorber 4 No light is emitted from the fourth reflective layer R4 on the side.
　その後、レーザ媒質３に第１発振光Ｌ１が吸収されて十分な励起状態となると、第２発振光Ｌ２の出力が上がり、ある閾値を超えると、可飽和吸収体４での光吸収率が急激に低下する。 After that, when the first oscillation light L1 is absorbed by the laser medium 3 and becomes in a sufficiently excited state, the output of the second oscillation light L2 increases, and when a certain threshold is exceeded, the light absorption rate in the saturable absorber 4 suddenly increases. decreases to
　これにより、第２共振器１２は、レーザ媒質３の第２反射層Ｒ２と、可飽和吸収体４の第４反射層Ｒ４との間で第２発振光Ｌ２を共振させ、反射層Ｒ４側から第２発振光Ｌ２がＱスイッチパルス波として出射される。 Thereby, the second resonator 12 causes the second oscillation light L2 to resonate between the second reflective layer R2 of the laser medium 3 and the fourth reflective layer R4 of the saturable absorber 4, and from the reflective layer R4 side. The second oscillation light L2 is emitted as a Q-switched pulse wave.
　図５Ｂの第２発振光Ｌ２は、受動Ｑスイッチ動作を行うことから、図５Ａの第１発振光Ｌ１よりも大きいピークパワーを有する。 Since the second oscillation light L2 in FIG. 5B performs a passive Q-switch operation, it has a larger peak power than the first oscillation light L1 in FIG. 5A.
　上述の通り、駆動電流又は温度の制御により、活性層２３は任意の波長の第３波長λ３と第４波長λ４の第１発振光Ｌ１を出射できる。例えば、第３波長λ３が図４Ｂの波長λa～λb内にあり、第４波長λ４が波長λc～λdの間にある場合は、第３反射層Ｒ３は、第３波長λ３に対する反射率よりも、第４波長λ４に対する反射率が高くなる。これにより、レーザ媒質３は、第３波長λ３の第１発振光Ｌ１に対しては第２発振光Ｌ２を励起させず、第４波長λ４の第１発振光Ｌ１に対しては第２発振光Ｌ２を励起させる。 As described above, by controlling the drive current or temperature, the active layer 23 can emit the first oscillation light L1 having the third wavelength λ3 and the fourth wavelength λ4, which are arbitrary wavelengths. For example, if the third wavelength λ3 is within the wavelengths λa to λb in FIG. , the reflectance for the fourth wavelength λ4 becomes high. As a result, the laser medium 3 does not excite the second oscillation light L2 with respect to the first oscillation light L1 with the third wavelength λ3, and excites the second oscillation light L2 with respect to the first oscillation light L1 with the fourth wavelength λ4. Excite L2.
　一方、第３波長λ３が図４Ｃの波長λc～λd内にあり、第４波長λ４が波長λe～λfの間にある場合は、第３反射層Ｒ３は、第３波長λ３に対する反射率よりも、第４波長λ４に対する反射率が低くなる。これにより、レーザ媒質３は、第４波長λ４の第１発振光Ｌ１に対しては第２発振光Ｌ２を励起させず、第３波長λ３の第１発振光Ｌ１に対しては第２発振光Ｌ２を励起させる。 On the other hand, if the third wavelength λ3 is within the wavelengths λc to λd in FIG. , the reflectance for the fourth wavelength λ4 becomes low. As a result, the laser medium 3 does not excite the second oscillation light L2 with respect to the first oscillation light L1 with the fourth wavelength λ4, and excites the second oscillation light L2 with respect to the first oscillation light L1 with the third wavelength λ3. Excite L2.
　なお、以降の説明においては、特に明示のない限り、第３波長λ３が図４Ｂの波長λa～λbの間にあり第４波長λ４が波長λc～λdの間にある場合（即ち、活性層２３に第１駆動電流Ｉ１を注入すると光源装置１は第１発振光Ｌ１を出射し、第２駆動電流Ｉ２を注入すると光源装置１が第２発振光Ｌ２を出射する場合）について説明する。 In the following description, unless otherwise specified, the third wavelength λ3 is between the wavelengths λa and λb in FIG. A case in which the light source device 1 emits the first oscillation light L1 when the first drive current I1 is injected into the drive current I1, and the light source device 1 emits the second oscillation light L2 when the second drive current I2 is injected will be described.
　このように、第１の実施形態においては、活性層２３は駆動電流に応じて、波長がそれぞれ異なる少なくとも２種類の第１発振光Ｌ１を出射することができる。また、第３反射層Ｒ３は、第１発振光Ｌ１のそれぞれ異なる波長に対して、それぞれ異なる反射率を有する。これにより、活性層２３に注入される駆動電流によって、第１発振光Ｌ１が第３反射層Ｒ３を透過するか、又は第３反射層Ｒ３で反射されるかを切り替えることができる。 In this way, in the first embodiment, the active layer 23 can emit at least two types of first oscillation light L1 having different wavelengths depending on the drive current. Further, the third reflective layer R3 has different reflectances for different wavelengths of the first oscillation light L1. Thereby, depending on the drive current injected into the active layer 23, it is possible to switch whether the first oscillation light L1 is transmitted through the third reflective layer R3 or reflected by the third reflective layer R3.
　第１発振光Ｌ１が第３波長λ３の場合は、レーザ媒質３は第２発振光Ｌ２を励起しないことから、光源装置１は比較的ピークパワーの低い第１発振光Ｌ１を出射する。第１発振光Ｌ１が第４波長λ４の場合は、レーザ媒質３は第２発振光Ｌ２を励起することから、光源装置１はＱスイッチパルス波の第２発振光Ｌ２を出射する。これにより、例えば測距を行う場合において、物体までの距離に応じて、活性層２３に注入する駆動電流を切り替えることで、ピークパワーの異なる第１発振光Ｌ１又は第２発振光Ｌ２を切り替えて出射できる。 When the first oscillation light L1 has the third wavelength λ3, the laser medium 3 does not excite the second oscillation light L2, so the light source device 1 emits the first oscillation light L1 with a relatively low peak power. When the first oscillation light L1 has the fourth wavelength λ4, the laser medium 3 excites the second oscillation light L2, so the light source device 1 emits the second oscillation light L2 in the form of a Q-switched pulse wave. As a result, when performing distance measurement, for example, by switching the drive current injected into the active layer 23 according to the distance to the object, the first oscillation light L1 or the second oscillation light L2 with different peak powers can be switched. Can be emitted.
　本開示の光源装置１によれば、例えば、ピークパワーをコントロールするために、外部に光学素子などの部品を追加する構成、あるいはメカ駆動を追加する構成よりも、簡便な構成で実現が可能である。このため、製造コストの削減でき、小型化が可能である。 According to the light source device 1 of the present disclosure, for example, in order to control peak power, it can be realized with a simpler configuration than a configuration in which components such as an optical element are added externally, or a configuration in which a mechanical drive is added. be. Therefore, manufacturing costs can be reduced and miniaturization possible.
　（第２の実施形態）
　第２の実施形態による光源装置１は、アレイ状の構造を有することを特徴とする。図６は、第２の実施形態における光源装置１の構成を示す断面図である。励起光源２は、第１発振光Ｌ１を出射する複数の第１領域Ａ１を有している。また、第３反射層Ｒ３は、第１領域Ａ１に対応する第２領域Ａ２を有している。 (Second embodiment)
The light source device 1 according to the second embodiment is characterized by having an array-like structure. FIG. 6 is a sectional view showing the configuration of the light source device 1 in the second embodiment. The excitation light source 2 has a plurality of first regions A1 that emit the first oscillation light L1. Further, the third reflective layer R3 has a second area A2 corresponding to the first area A1.
　第１領域Ａ１は、複数のサブ領域に分かれており、サブ領域によって活性層２３の駆動条件が異なる。この場合、第１領域Ａ１内の隣接する２つのサブ領域は、互いに異なる第１波長λ１を有する第１発振光Ｌ１を出射する。また、第２領域Ａ２も、複数のサブ領域に分かれている。第２領域Ａ２内の隣接する２つのサブ領域は、第１領域Ａ１内の対応するサブ領域が出射した第１発振光Ｌ１の波長に応じた反射率を有する。 The first region A1 is divided into a plurality of sub-regions, and the driving conditions for the active layer 23 differ depending on the sub-regions. In this case, two adjacent sub-regions within the first region A1 emit the first oscillation light L1 having mutually different first wavelengths λ1. Further, the second area A2 is also divided into a plurality of sub-areas. Two adjacent sub-regions in the second region A2 have reflectances that correspond to the wavelength of the first oscillation light L1 emitted by the corresponding sub-regions in the first region A1.
例えば、図６の例においては、第１領域Ａ１は、第３波長λ３の第１発振光Ｌ１を出射するサブ領域Ａ１１と、第４波長λ４の第１発振光Ｌ１を出射するサブ領域Ａ１２とを有する。第２領域Ａ２は、サブ領域Ａ１１からの第１発振光Ｌ１が入射されるサブ領域Ａ２１と、サブ領域Ａ１２からの第１発振光Ｌ１が入射されるサブ領域Ａ２２とを有する。 For example, in the example of FIG. 6, the first region A1 includes a sub-region A11 that emits the first oscillation light L1 with the third wavelength λ3, and a sub-region A12 that emits the first oscillation light L1 with the fourth wavelength λ4. has. The second area A2 includes a sub area A21 into which the first oscillation light L1 from the sub area A11 is incident, and a sub area A22 into which the first oscillation light L1 from the sub area A12 is incident.
　第２領域Ａ２内のサブ領域Ａ２１は、第３波長λ３に対する反射率Ｒaを有する。また、第２領域Ａ２内のサブ領域Ａ２２は第４波長λ４に対する反射率Ｒbを有する。 The sub-region A21 within the second region A2 has a reflectance Ra for the third wavelength λ3. Furthermore, the sub-area A22 within the second area A2 has a reflectance Rb for the fourth wavelength λ4.
　第４反射層Ｒ４からは、ピークパワーの低い第１発振光Ｌ１と、ピークパワーの高い第２発振光Ｌ２とが、それぞれ出射される。 A first oscillation light L1 with a low peak power and a second oscillation light L2 with a high peak power are respectively emitted from the fourth reflective layer R4.
　第１領域Ａ１内のサブ領域Ａ１１、Ａ１２のサイズ、配置数、及び配置方向は任意である。図７Ａは、第２の実施形態における光源装置１の市松模様状の発光を示す図である。サブ領域Ａ１１、Ａ１２を市松模様状に配置することで、図７Ａに示すように、第１発振光Ｌ１、 第２発振光Ｌ２を市松模様状に発光できる。図７Ｂは、第２の実施形態における光源装置１のライン＆スペースパターンでの発光を示す図である。サブ領域Ａ１１、Ａ１２を、１行又は１列ごとに、交互に配置することで、図７Ｂに示すように、第１発振光Ｌ１、 第２発振光Ｌ２をライン＆スペースパターンで発光できる。 The size, number, and direction of arrangement of the sub-areas A11 and A12 within the first area A1 are arbitrary. FIG. 7A is a diagram showing checkered pattern light emission of the light source device 1 in the second embodiment. By arranging the sub-regions A11 and A12 in a checkerboard pattern, the first oscillation light L1 and second oscillation light L2 can be emitted in a checkerboard pattern, as shown in FIG. 7A. FIG. 7B is a diagram showing light emission in a line and space pattern of the light source device 1 in the second embodiment. By alternately arranging the sub-regions A11 and A12 in every row or column, the first oscillation light L1 and the second oscillation light L2 can be emitted in a line-and-space pattern, as shown in FIG. 7B.
　このように、第２の実施形態においては、光源装置１から、ピークパワーの異なる複数の第１反射光Ｌ１を同時に出射することができる。よって、例えば、近距離の測距と遠距離の測距を同タイミングで行うことができる。 In this manner, in the second embodiment, a plurality of first reflected lights L1 having different peak powers can be emitted simultaneously from the light source device 1. Therefore, for example, short-distance distance measurement and long-distance distance measurement can be performed at the same timing.
　（第３の実施形態）
　第１の実施形態の光源装置１は、活性層２３に注入する駆動電流を切り替えることで、連続波の第１発振光Ｌ１を出射するか、又はＱスイッチパルス波の第２発振光Ｌ２を出射するかを切り替える。第１発振光Ｌ１は、第２発振光Ｌ２と同様に、パルス光にすることができる。第３の実施形態においては、活性層２３に注入する駆動電流をパルス電流にすることで、第１発振光Ｌ１をパルス光とする。これにより、第３の実施形態の光源装置１は、第１波長λ１と第２波長λ２を切り替え可能なパルス光源として用いることができる。 (Third embodiment)
The light source device 1 of the first embodiment emits the continuous wave first oscillation light L1 or the Q-switched pulse wave second oscillation light L2 by switching the drive current injected into the active layer 23. toggle between The first oscillation light L1 can be pulsed light similarly to the second oscillation light L2. In the third embodiment, the first oscillation light L1 is made into pulsed light by making the drive current injected into the active layer 23 into a pulsed current. Thereby, the light source device 1 of the third embodiment can be used as a pulsed light source that can switch between the first wavelength λ1 and the second wavelength λ2.
　より詳細には、第３の実施形態においては、活性層２３に注入する第１駆動電流Ｉ１をパルス電流とする。図８Ａは、活性層２３に注入するパルス電流波形を示す図である。横軸は時間を示し、縦軸は駆動電流の大きさを示す。活性層２３には、所定の時間間隔Δｔ’ごとに、パルス電流である第１駆動電流Ｉ１が注入される。パルス電流のパルス幅とパルス間隔をＰＷＭ制御することで、第３波長λ３の第１発振光Ｌ１のピークパワーを任意に調整できる。 More specifically, in the third embodiment, the first drive current I1 injected into the active layer 23 is a pulse current. FIG. 8A is a diagram showing a pulse current waveform injected into the active layer 23. The horizontal axis shows time, and the vertical axis shows the magnitude of drive current. A first drive current I1, which is a pulse current, is injected into the active layer 23 at predetermined time intervals Δt'. By performing PWM control on the pulse width and pulse interval of the pulse current, the peak power of the first oscillation light L1 having the third wavelength λ3 can be arbitrarily adjusted.
　図８Ａのパルス電流により、第３の実施形態における励起光源２は第１波長λ１の第１発振光Ｌ１を間欠的に出射する。図８Ｂは、第３の実施形態における光源装置１から出射される第１発振光Ｌ１の波形図である。横軸は時間を示し、縦軸はピークパワーを示す。第３の実施形態における励起光源２は、上述の時間間隔Δｔ’ごとに、ピークパワーＰ１を有する第１波長λ１の第１発振光Ｌ１を出力する。即ち、これにより、第３の実施形態の光源装置１は、第２発振光Ｌ２と同様のパルス波として、第１波長λ１の第１発振光Ｌ１を出力する。 Due to the pulse current shown in FIG. 8A, the excitation light source 2 in the third embodiment intermittently emits the first oscillation light L1 having the first wavelength λ1. FIG. 8B is a waveform diagram of the first oscillation light L1 emitted from the light source device 1 in the third embodiment. The horizontal axis shows time, and the vertical axis shows peak power. The excitation light source 2 in the third embodiment outputs the first oscillation light L1 having the peak power P1 and the first wavelength λ1 at each time interval Δt' described above. That is, thereby, the light source device 1 of the third embodiment outputs the first oscillation light L1 having the first wavelength λ1 as a pulse wave similar to the second oscillation light L2.
　図８Ｃは、光源装置から出射される第２発振光Ｌ２の波形図である。横軸は時間を示し、縦軸はピークパワーを示す。光源装置１は、時間間隔Δｔごとに、ピークパワーＰ２を有する第２発振光Ｌ２を出力する。 FIG. 8C is a waveform diagram of the second oscillation light L2 emitted from the light source device. The horizontal axis shows time, and the vertical axis shows peak power. The light source device 1 outputs the second oscillation light L2 having the peak power P2 at every time interval Δt.
　第１発振光Ｌ１のパルス間隔（時間間隔Δｔ’）は、活性層２３に注入される駆動電流のパルス間隔により決定される。一方、第２発振光Ｌ２のパルス間隔（時間間隔Δｔ）は、レーザ媒質３及び可飽和吸収体４の材料及び厚さ、第１～第４反射層Ｒ１～Ｒ４の反射率、及び活性層２３に注入される駆動電流などにより決定される。 The pulse interval (time interval Δt') of the first oscillation light L1 is determined by the pulse interval of the drive current injected into the active layer 23. On the other hand, the pulse interval (time interval Δt) of the second oscillation light L2 depends on the materials and thicknesses of the laser medium 3 and the saturable absorber 4, the reflectance of the first to fourth reflective layers R1 to R4, and the active layer 23. It is determined by the drive current injected into the
　第２駆動電流Ｉ２についても、図８Ａと同様にパルス電流として与えてもよい。これにより、第２発振光Ｌ２のパルス間隔は、上記の条件に加え、第２駆動電流Ｉ２のパルス間隔によっても制御できる。 The second drive current I2 may also be applied as a pulse current similarly to FIG. 8A. Thereby, the pulse interval of the second oscillation light L2 can be controlled not only by the above conditions but also by the pulse interval of the second drive current I2.
　このように、第３の実施形態の光源装置１は、第３波長λ３の第１発振光Ｌ１を任意のパルス間隔のパルス光にすることができる。よって、光源装置１からは、波長の異なるパルス光を切り替えて出射することができ、光源装置１から出射されたパルス光を例えば測距用の発光信号として用いることができる。 In this way, the light source device 1 of the third embodiment can turn the first oscillation light L1 of the third wavelength λ3 into pulsed light with an arbitrary pulse interval. Therefore, the light source device 1 can switch and emit pulsed light having different wavelengths, and the pulsed light emitted from the light source device 1 can be used, for example, as a light emission signal for distance measurement.
　（第４の実施形態）
　本開示の光源装置１は、例えば測距装置に適用できる。図９は、第４の実施形態に係る光源装置１の一実装例としての測距装置６０の構成例を示している。測距装置６０は、発光部６１、駆動部６２、電源回路６３、発光側光学系６４、受光側光学系６５、受光部６６、信号処理部６７、制御部６８、及び温度検出部６９を備えている。 (Fourth embodiment)
The light source device 1 of the present disclosure can be applied to, for example, a distance measuring device. FIG. 9 shows a configuration example of a distance measuring device 60 as an example of implementation of the light source device 1 according to the fourth embodiment. The distance measuring device 60 includes a light emitting section 61, a driving section 62, a power supply circuit 63, a light emitting side optical system 64, a light receiving side optical system 65, a light receiving section 66, a signal processing section 67, a control section 68, and a temperature detecting section 69. ing.
　発光部６１は、光源として光源装置１を有し、発光部６１は、光源装置１を複数有してもよいし、例えばマトリクス状等の所定態様により配列された光源装置１により構成されていてもよい。 The light emitting section 61 has a light source device 1 as a light source, and the light emitting section 61 may have a plurality of light source devices 1, or may be constituted by light source devices 1 arranged in a predetermined manner, such as a matrix. Good too.
　駆動部６２は、発光部６１を駆動するための電源回路６３を有して構成される。電源回路６３は、例えば測距装置６０に設けられた不図示のバッテリ等からの入力電流に基づき、駆動部６２の電源電流を生成する。駆動部６２は、該電源電流に基づいて発光部６１内に配置された光源装置１の活性層２３に、駆動電流を供給する。 The driving section 62 is configured to include a power supply circuit 63 for driving the light emitting section 61. The power supply circuit 63 generates a power supply current for the drive unit 62 based on an input current from, for example, a battery (not shown) provided in the distance measuring device 60. The drive section 62 supplies a drive current to the active layer 23 of the light source device 1 disposed within the light emitting section 61 based on the power supply current.
　また、駆動部６２は、光源装置１の発光を示す発光信号を、発光部６１から取り込む。発光信号は、制御部６８の測距部（距離計測部）６８ａに供給される。発光信号は、測距部６８ａに直接供給されてもよいし、受光部６６を介して測距部６８ａに供給されてもよい。 Further, the driving section 62 takes in a light emission signal indicating light emission from the light source device 1 from the light emitting section 61. The light emission signal is supplied to a distance measuring section (distance measuring section) 68a of the control section 68. The light emission signal may be supplied directly to the distance measuring section 68a, or may be supplied to the distance measuring section 68a via the light receiving section 66.
　駆動部６２は、測距対象（図９では、被写体Ｓ）との距離に応じて、活性層２３に供給する駆動電流を変化させてもよい。 The drive unit 62 may change the drive current supplied to the active layer 23 depending on the distance to the distance measurement target (subject S in FIG. 9).
　発光部６１より発せられた光は、発光側光学系６４を介して測距対象としての被写体（対象物）Ｓに照射される。そして、このように照射された光の被写体Ｓからの反射光は、受光側光学系６５を介して受光部６６の受光面に入射する。 The light emitted from the light emitting unit 61 is irradiated onto the subject (object) S as a distance measurement target via the light emitting side optical system 64. Then, the reflected light from the subject S of the light irradiated in this way enters the light receiving surface of the light receiving section 66 via the light receiving side optical system 65.
　受光部６６は、例えばＣＣＤ（Charge Coupled Device）センサやＣＭＯＳ（Complementary Metal Oxide Semiconductor）センサ等の受光素子とされ、上記のように受光側光学系６５を介して入射する被写体Ｓからの反射光を受光し、電気信号に変換して出力する。 The light receiving section 66 is, for example, a light receiving element such as a CCD (Charge Coupled Device) sensor or a CMOS (Complementary Metal Oxide Semiconductor) sensor, and receives reflected light from the subject S that enters through the light receiving side optical system 65 as described above. It receives light, converts it into an electrical signal, and outputs it.
　受光部６６は、受光した光を光電変換して得た電気信号について、例えばＣＤＳ(Correlated Double Sampling)処理、ＡＧＣ(Automatic Gain Control)処理などを実行し、さらにＡ／Ｄ(Analog/Digital)変換処理を行う。そしてデジタルデータとしての信号（受光信号）を、後段の信号処理部６７に出力する。 The light receiving unit 66 performs, for example, CDS (Correlated Double Sampling) processing, AGC (Automatic Gain Control) processing, etc. on the electrical signal obtained by photoelectrically converting the received light, and further performs A/D (Analog/Digital) conversion. Perform processing. Then, the signal as digital data (light reception signal) is output to the subsequent signal processing section 67.
　また、本例の受光部６６は、フレーム同期信号Ｆｓを駆動部６２に出力する。これにより駆動部６２は、発光部６１における光源装置１を受光部６６のフレーム周期に応じたタイミングで発光させることが可能とされる。 Furthermore, the light receiving section 66 of this example outputs a frame synchronization signal Fs to the driving section 62. This allows the driving section 62 to cause the light source device 1 in the light emitting section 61 to emit light at a timing corresponding to the frame period of the light receiving section 66.
　信号処理部６７は、例えばＤＳＰ（Digital Signal Processor）等により信号処理プロセッサとして構成される。信号処理部６７は、受光部６６から入力される受光信号に対して、各種の信号処理を施す。 The signal processing unit 67 is configured as a signal processing processor using, for example, a DSP (Digital Signal Processor). The signal processing section 67 performs various signal processing on the light reception signal input from the light receiving section 66.
　制御部６８は、例えばＣＰＵ（Central Processing Unit）、ＲＯＭ（Read Only Memory）、ＲＡＭ（Random Access Memory）等を有するマイクロコンピュータ、或いはＤＳＰ等の情報処理装置を備えて構成され、発光部６１による発光動作を制御するための駆動部６２の制御や、受光部６６による受光動作に係る制御を行う。 The control unit 68 includes, for example, a microcomputer having a CPU (Central Processing Unit), ROM (Read Only Memory), RAM (Random Access Memory), etc., or an information processing device such as a DSP, and controls the light emission by the light emission unit 61. It controls the driving section 62 for controlling the operation and controls the light receiving operation of the light receiving section 66.
　制御部６８は、測距部６８ａとしての機能を有する。測距部６８ａは、信号処理部６７により信号処理された受光信号と、駆動部６２から供給された光源装置１の発光信号に基づき、被写体Ｓまでの距離を測定する。本例の測距部６８ａは、被写体Ｓの三次元形状の特定を可能とするために、被写体Ｓの各部について距離の測定を行う。 The control section 68 has a function as a distance measuring section 68a. The distance measuring section 68a measures the distance to the subject S based on the light reception signal signal-processed by the signal processing section 67 and the light emission signal of the light source device 1 supplied from the driving section 62. The distance measuring unit 68a of this example measures the distance of each part of the subject S to enable identification of the three-dimensional shape of the subject S.
　制御部６８は、測距部６８ａが被写体Ｓとの距離を測定するたびに、駆動部６２に被写体Ｓとの距離を通知してもよい。 The control unit 68 may notify the driving unit 62 of the distance to the subject S every time the distance measuring unit 68a measures the distance to the subject S.
　温度検出部６９は、発光部６１の温度を検出する。温度検出部６９としては、例えばダイオードを用いて温度検出を行う構成を採ることができる。 The temperature detection section 69 detects the temperature of the light emitting section 61. As the temperature detection section 69, a configuration may be adopted in which temperature detection is performed using, for example, a diode.
　本例では、温度検出部６９により検出された温度の情報は駆動部６２に供給され、これにより駆動部６２は該温度の情報に基づいて発光部６１の駆動を行うことが可能とされる。 In this example, information on the temperature detected by the temperature detection section 69 is supplied to the driving section 62, thereby enabling the driving section 62 to drive the light emitting section 61 based on the temperature information.
　測距装置６０における測距手法としては、例えばＳＴＬ（Structured Light：構造化光）方式やＴｏＦ（Time of Flight：光飛行時間）方式による測距手法を採用することができる。 As the distance measuring method in the distance measuring device 60, for example, a distance measuring method using an STL (Structured Light) method or a ToF (Time of Flight) method can be adopted.
　ＳＴＬ方式を採用する場合、受光部６６としては、例えばグローバルシャッタ方式によるＩＲ（Infrared：赤外線）受光部が用いられる。そして、ＳＴＬ方式の場合、測距部６８ａは、発光部６１がパターン光を発光するように駆動部６２を制御すると共に、信号処理部６７を介して得られる画像信号についてパターンの歪みを検出し、パターンの歪み方に基づいて距離を計算する。 When adopting the STL method, the light receiving section 66 is, for example, an IR (Infrared) light receiving section using a global shutter method. In the case of the STL method, the distance measuring section 68a controls the driving section 62 so that the light emitting section 61 emits pattern light, and detects pattern distortion in the image signal obtained via the signal processing section 67. , calculate the distance based on how the pattern is distorted.
　一方、ＴｏＦ方式は、発光部６１より発された光が対象物で反射されて受光部６６に到達するまでの光の飛行時間（時間差）を検出することで、対象物までの距離を測定する方式である。 On the other hand, the ToF method measures the distance to the target object by detecting the flight time (time difference) of the light emitted from the light emitting unit 61 until it is reflected by the target object and reaches the light receiving unit 66. It is a method.
　ＴｏＦ方式として、いわゆるダイレクトＴｏＦ(dToF)方式を採用する場合、受光部６６としてはＳＰＡＤ（Single Photon Avalanche Diode）を用い、また発光部６１はパルス駆動する。この場合、測距部６８ａは、信号処理部６７を介して入力される信号に基づき、発光部６１より発せられ受光部６６により受光される光について発光から受光までの時間差を計算し、該時間差と光の速度とに基づいて被写体Ｓの各部の距離を計算する。 When a so-called direct ToF (dToF) method is adopted as the ToF method, a SPAD (Single Photon Avalanche Diode) is used as the light receiving section 66, and the light emitting section 61 is pulse-driven. In this case, the distance measuring section 68a calculates the time difference between light emission and light reception for the light emitted from the light emitting section 61 and received by the light receiving section 66 based on the signal inputted via the signal processing section 67, and calculates the time difference between light emission and light reception. The distance to each part of the subject S is calculated based on the distance and the speed of light.
　なお、ＴｏＦ方式として、いわゆるインダイレクトＴｏＦ(iToF)方式（位相差法）を採用する場合、受光部６６としては例えばＩＲを受光することのできる受光部が用いられる。 Note that when a so-called indirect ToF (iToF) method (phase difference method) is adopted as the ToF method, a light receiving portion capable of receiving IR light is used as the light receiving portion 66, for example.
　測距装置６０による測距においては、被写体Ｓとの距離に応じて、被写体Ｓに出射するレーザ光を切り替えてもよい。図１０Ａ及び図１０Ｂは、測距装置６０内の光源装置１が、被写体Ｓにレーザ光を出射する例を示す図である。 In distance measurement by the distance measuring device 60, the laser light emitted to the subject S may be switched depending on the distance to the subject S. 10A and 10B are diagrams showing an example in which the light source device 1 in the distance measuring device 60 emits a laser beam to the subject S.
　制御部６８は、測距部６８ａが被写体Ｓとの距離を測定するたびに、駆動部６２に被写体Ｓとの距離を通知する。被写体Ｓが測距装置６０から近距離にある場合、レーザ光のピークパワーは低い方が望ましい。 The control unit 68 notifies the driving unit 62 of the distance to the subject S every time the distance measuring unit 68a measures the distance to the subject S. When the subject S is at a short distance from the distance measuring device 60, it is desirable that the peak power of the laser beam is low.
　図１０Ａは、被写体Ｓが測距装置６０から近距離にある場合の、光源装置１のレーザ光の出射動作を示す図である。図１０Ａにおいて、駆動部６２は第１駆動電流Ｉ１を活性層２３に注入する。これにより、活性層２３は第３波長λ３の第１発振光Ｌ１を出射する。第３波長λ３の第１発振光Ｌ１は第３反射層Ｒ３を透過することから、レーザ媒質３は第２発振光Ｌ２を励起させない。結果として、光源装置１はピークパワーの低い第１発振光Ｌ１を、被写体Ｓに出射する。被写体Ｓに照射された第１発振光Ｌ１は被写体Ｓで反射されて受光部６６で受光され、測距部６８ａで近距離の距離計測が行われる。この場合の第１反射光Ｌ１は、ピークパワーが低くて遠方までは届かないため、近距離の測距に用いられる。 FIG. 10A is a diagram showing the laser beam emitting operation of the light source device 1 when the subject S is at a short distance from the distance measuring device 60. In FIG. 10A, the drive unit 62 injects the first drive current I1 into the active layer 23. As a result, the active layer 23 emits the first oscillation light L1 having the third wavelength λ3. Since the first oscillation light L1 having the third wavelength λ3 is transmitted through the third reflective layer R3, the laser medium 3 does not excite the second oscillation light L2. As a result, the light source device 1 emits the first oscillation light L1 with low peak power to the subject S. The first oscillation light L1 irradiated onto the subject S is reflected by the subject S and received by the light receiving section 66, and short distance measurement is performed by the distance measuring section 68a. In this case, the first reflected light L1 has a low peak power and does not reach far, so it is used for short distance measurement.
　一方、被写体Ｓが測距装置６０から遠距離にある場合、レーザ光のピークパワーは高い方が望ましい。図１０Ｂは、被写体Ｓが測距装置６０から遠距離にある場合の、光源装置１のレーザ光の出射動作を示す図である。図１０Ｂにおいて、駆動部６２は第２駆動電流Ｉ２を活性層２３に注入する。これにより、活性層２３は第４波長λ４の第１発振光Ｌ１を出射する。第４波長λ４の励起光Ｌ２は第１反射層Ｒ１と第３反射層Ｒ３の間で繰り返し反射され、レーザ媒質３に十分な量の第１反射光Ｌ１が吸収されることから、レーザ媒質３は第２発振光Ｌ２を励起する。第２発振光Ｌ２は、第２反射層Ｒ２と第４反射層Ｒ４の間で反射を繰り返し、可飽和吸収体４に十分な量の第２発振光Ｌ２が吸収された段階で、光源装置１はピークパワーの高い第２発振光Ｌ２を、被写体Ｓに出射する。第２発振光Ｌ２は遠距離の距離計測に用いられる。 On the other hand, when the subject S is far away from the distance measuring device 60, it is desirable that the peak power of the laser beam is high. FIG. 10B is a diagram showing the laser beam emitting operation of the light source device 1 when the subject S is far away from the distance measuring device 60. In FIG. 10B, the drive unit 62 injects the second drive current I2 into the active layer 23. Thereby, the active layer 23 emits the first oscillation light L1 having the fourth wavelength λ4. The excitation light L2 with the fourth wavelength λ4 is repeatedly reflected between the first reflective layer R1 and the third reflective layer R3, and a sufficient amount of the first reflected light L1 is absorbed by the laser medium 3. excites the second oscillation light L2. The second oscillation light L2 is repeatedly reflected between the second reflection layer R2 and the fourth reflection layer R4, and when a sufficient amount of the second oscillation light L2 is absorbed by the saturable absorber 4, the light source device 1 emits the second oscillation light L2 with high peak power to the subject S. The second oscillation light L2 is used for long distance measurement.
　駆動部６２は、測距装置６０での測距結果に基づいて、活性層２３に注入する駆動電流を切り替えてもよい。これにより、被写体Ｓの距離によって、最適なピークパワーの発振光を光源装置１から出射できる。 The drive unit 62 may switch the drive current injected into the active layer 23 based on the distance measurement result by the distance measurement device 60. Thereby, depending on the distance of the subject S, the light source device 1 can emit oscillated light with an optimal peak power.
　このように、第４の実施形態の測距装置６０は、第１～第３の実施形態のいずれかの光源装置１を用いて、被写体Ｓとの距離に応じて、出射するレーザ光を切り替えることができる。遠距離にある被写体Ｓに対してはよりピークパワーの高いレーザ光を出射し、また、近距離にある被写体Ｓに対してはレーザ安全を考慮して、よりピークパワーの低いレーザ光を出射する等、状況に応じてレーザ光を使い分けることができる。 In this way, the distance measuring device 60 of the fourth embodiment switches the emitted laser light according to the distance to the subject S using the light source device 1 of any of the first to third embodiments. be able to. A laser beam with a higher peak power is emitted to a subject S at a far distance, and a laser beam with a lower peak power is emitted to a subject S at a close distance, taking laser safety into consideration. etc., laser light can be used depending on the situation.
（移動体への応用例）
　本開示に係る技術（本技術）は、様々な製品へ応用することができる。例えば、本開示に係る技術は、自動車、電気自動車、ハイブリッド電気自動車、自動二輪車、自転車、パーソナルモビリティ、飛行機、ドローン、船舶、ロボット等のいずれかの種類の移動体に搭載される装置として実現されてもよい。 (Example of application to mobile objects)
The technology according to the present disclosure (this technology) can be applied to various products. For example, the technology according to the present disclosure may be realized as a device mounted on any type of moving body such as a car, electric vehicle, hybrid electric vehicle, motorcycle, bicycle, personal mobility, airplane, drone, ship, robot, etc. It's okay.
　図１１は、本開示に係る技術が適用され得る移動体制御システムの一例である車両制御システムの概略的な構成例を示すブロック図である。 FIG. 11 is a block diagram illustrating a schematic configuration example of a vehicle control system, which is an example of a mobile body control system to which the technology according to the present disclosure can be applied.
　車両制御システム１２０００は、通信ネットワーク１２００１を介して接続された複数の電子制御ユニットを備える。図１１に示した例では、車両制御システム１２０００は、駆動系制御ユニット１２０１０、ボディ系制御ユニット１２０２０、車外情報検出ユニット１２０３０、車内情報検出ユニット１２０４０、及び統合制御ユニット１２０５０を備える。また、統合制御ユニット１２０５０の機能構成として、マイクロコンピュータ１２０５１、音声画像出力部１２０５２、及び車載ネットワークＩ／Ｆ（ｉｎｔｅｒｆａｃｅ）１２０５３が図示されている。 The vehicle control system 12000 includes a plurality of electronic control units connected via a communication network 12001. In the example shown in FIG. 11, the vehicle control system 12000 includes a drive system control unit 12010, a body system control unit 12020, an outside vehicle information detection unit 12030, an inside vehicle information detection unit 12040, and an integrated control unit 12050. Further, as the functional configuration of the integrated control unit 12050, a microcomputer 12051, an audio/image output section 12052, and an in-vehicle network I/F (interface) 12053 are illustrated.
　駆動系制御ユニット１２０１０は、各種プログラムにしたがって車両の駆動系に関連する装置の動作を制御する。例えば、駆動系制御ユニット１２０１０は、内燃機関又は駆動用モータ等の車両の駆動力を発生させるための駆動力発生装置、駆動力を車輪に伝達するための駆動力伝達機構、車両の舵角を調節するステアリング機構、及び、車両の制動力を発生させる制動装置等の制御装置として機能する。 The drive system control unit 12010 controls the operation of devices related to the drive system of the vehicle according to various programs. For example, the drive system control unit 12010 includes a drive force generation device such as an internal combustion engine or a drive motor that generates drive force for the vehicle, a drive force transmission mechanism that transmits the drive force to wheels, and a drive force transmission mechanism that controls the steering angle of the vehicle. It functions as a control device for a steering mechanism to adjust and a braking device to generate braking force for the vehicle.
　ボディ系制御ユニット１２０２０は、各種プログラムにしたがって車体に装備された各種装置の動作を制御する。例えば、ボディ系制御ユニット１２０２０は、キーレスエントリシステム、スマートキーシステム、パワーウィンドウ装置、あるいは、ヘッドランプ、バックランプ、ブレーキランプ、ウィンカー又はフォグランプ等の各種ランプの制御装置として機能する。この場合、ボディ系制御ユニット１２０２０には、鍵を代替する携帯機から発信される電波又は各種スイッチの信号が入力され得る。ボディ系制御ユニット１２０２０は、これらの電波又は信号の入力を受け付け、車両のドアロック装置、パワーウィンドウ装置、ランプ等を制御する。 The body system control unit 12020 controls the operations of various devices installed in the vehicle body according to various programs. For example, the body system control unit 12020 functions as a keyless entry system, a smart key system, a power window device, or a control device for various lamps such as a headlamp, a back lamp, a brake lamp, a turn signal, or a fog lamp. In this case, radio waves transmitted from a portable device that replaces a key or signals from various switches may be input to the body control unit 12020. The body system control unit 12020 receives input of these radio waves or signals, and controls the door lock device, power window device, lamp, etc. of the vehicle.
　車外情報検出ユニット１２０３０は、車両制御システム１２０００を搭載した車両の外部の情報を検出する。例えば、車外情報検出ユニット１２０３０には、撮像部１２０３１が接続される。車外情報検出ユニット１２０３０は、撮像部１２０３１に車外の画像を撮像させるとともに、撮像された画像を受信する。車外情報検出ユニット１２０３０は、受信した画像に基づいて、人、車、障害物、標識又は路面上の文字等の物体検出処理又は距離検出処理を行ってもよい。 The external information detection unit 12030 detects information external to the vehicle in which the vehicle control system 12000 is mounted. For example, an imaging section 12031 is connected to the outside-vehicle information detection unit 12030. The vehicle exterior information detection unit 12030 causes the imaging unit 12031 to capture an image of the exterior of the vehicle, and receives the captured image. The external information detection unit 12030 may perform object detection processing such as a person, car, obstacle, sign, or text on the road surface or distance detection processing based on the received image.
　撮像部１２０３１は、光を受光し、その光の受光量に応じた電気信号を出力する光センサである。撮像部１２０３１は、電気信号を画像として出力することもできるし、測距の情報として出力することもできる。また、撮像部１２０３１が受光する光は、可視光であっても良いし、赤外線等の非可視光であっても良い。 The imaging unit 12031 is an optical sensor that receives light and outputs an electrical signal according to the amount of received light. The imaging unit 12031 can output the electrical signal as an image or as distance measurement information. Further, the light received by the imaging unit 12031 may be visible light or non-visible light such as infrared rays.
　車内情報検出ユニット１２０４０は、車内の情報を検出する。車内情報検出ユニット１２０４０には、例えば、運転者の状態を検出する運転者状態検出部１２０４１が接続される。運転者状態検出部１２０４１は、例えば運転者を撮像するカメラを含み、車内情報検出ユニット１２０４０は、運転者状態検出部１２０４１から入力される検出情報に基づいて、運転者の疲労度合い又は集中度合いを算出してもよいし、運転者が居眠りをしていないかを判別してもよい。 The in-vehicle information detection unit 12040 detects in-vehicle information. For example, a driver condition detection section 12041 that detects the condition of the driver is connected to the in-vehicle information detection unit 12040. The driver condition detection unit 12041 includes, for example, a camera that images the driver, and the in-vehicle information detection unit 12040 detects the degree of fatigue or concentration of the driver based on the detection information input from the driver condition detection unit 12041. It may be calculated, or it may be determined whether the driver is falling asleep.
　マイクロコンピュータ１２０５１は、車外情報検出ユニット１２０３０又は車内情報検出ユニット１２０４０で取得される車内外の情報に基づいて、駆動力発生装置、ステアリング機構又は制動装置の制御目標値を演算し、駆動系制御ユニット１２０１０に対して制御指令を出力することができる。例えば、マイクロコンピュータ１２０５１は、車両の衝突回避あるいは衝撃緩和、車間距離に基づく追従走行、車速維持走行、車両の衝突警告、又は車両のレーン逸脱警告等を含むＡＤＡＳ（Ａｄｖａｎｃｅｄ　Ｄｒｉｖｅｒ　Ａｓｓｉｓｔａｎｃｅ　Ｓｙｓｔｅｍ）の機能実現を目的とした協調制御を行うことができる。 The microcomputer 12051 calculates control target values for the driving force generation device, steering mechanism, or braking device based on the information inside and outside the vehicle acquired by the vehicle exterior information detection unit 12030 or the vehicle interior information detection unit 12040, Control commands can be output to 12010. For example, the microcomputer 12051 realizes ADAS (Advanced Driver Assistance System) functions, including vehicle collision avoidance or impact mitigation, following distance based on vehicle distance, vehicle speed maintenance, vehicle collision warning, vehicle lane departure warning, etc. It is possible to perform cooperative control for the purpose of
　また、マイクロコンピュータ１２０５１は、車外情報検出ユニット１２０３０又は車内情報検出ユニット１２０４０で取得される車両の周囲の情報に基づいて駆動力発生装置、ステアリング機構又は制動装置等を制御することにより、運転者の操作に拠らずに自律的に走行する自動運転等を目的とした協調制御を行うことができる。 In addition, the microcomputer 12051 controls the driving force generating device, steering mechanism, braking device, etc. based on information about the surroundings of the vehicle acquired by the vehicle exterior information detection unit 12030 or the vehicle interior information detection unit 12040. It is possible to perform cooperative control for the purpose of autonomous driving, etc., which does not rely on operation.
　また、マイクロコンピュータ１２０５１は、車外情報検出ユニット１２０３０で取得される車外の情報に基づいて、ボディ系制御ユニット１２０２０に対して制御指令を出力することができる。例えば、マイクロコンピュータ１２０５１は、車外情報検出ユニット１２０３０で検知した先行車又は対向車の位置に応じてヘッドランプを制御し、ハイビームをロービームに切り替える等の防眩を図ることを目的とした協調制御を行うことができる。 Furthermore, the microcomputer 12051 can output a control command to the body system control unit 12020 based on the information outside the vehicle acquired by the outside information detection unit 12030. For example, the microcomputer 12051 controls the headlamps according to the position of the preceding vehicle or oncoming vehicle detected by the vehicle exterior information detection unit 12030, and performs cooperative control for the purpose of preventing glare, such as switching from high beam to low beam. It can be carried out.
　音声画像出力部１２０５２は、車両の搭乗者又は車外に対して、視覚的又は聴覚的に情報を通知することが可能な出力装置へ音声及び画像のうちの少なくとも一方の出力信号を送信する。図１１の例では、出力装置として、オーディオスピーカ１２０６１、表示部１２０６２及びインストルメントパネル１２０６３が例示されている。表示部１２０６２は、例えば、オンボードディスプレイ及びヘッドアップディスプレイの少なくとも一つを含んでいてもよい。 The audio and image output unit 12052 transmits an output signal of at least one of audio and images to an output device that can visually or audibly notify information to the occupants of the vehicle or to the outside of the vehicle. In the example of FIG. 11, an audio speaker 12061, a display section 12062, and an instrument panel 12063 are illustrated as output devices. The display unit 12062 may include, for example, at least one of an on-board display and a head-up display.
　図１２は、撮像部１２０３１の設置位置の例を示す図である。 FIG. 12 is a diagram showing an example of the installation position of the imaging section 12031.
　図１２では、車両１２１００は、撮像部１２０３１として、撮像部１２１０１，１２１０２，１２１０３，１２１０４，１２１０５を有する。 In FIG. 12, the vehicle 12100 has imaging units 12101, 12102, 12103, 12104, and 12105 as the imaging unit 12031.
　撮像部１２１０１，１２１０２，１２１０３，１２１０４，１２１０５は、例えば、車両１２１００のフロントノーズ、サイドミラー、リアバンパ、バックドア及び車室内のフロントガラスの上部等の位置に設けられる。フロントノーズに備えられる撮像部１２１０１及び車室内のフロントガラスの上部に備えられる撮像部１２１０５は、主として車両１２１００の前方の画像を取得する。サイドミラーに備えられる撮像部１２１０２，１２１０３は、主として車両１２１００の側方の画像を取得する。リアバンパ又はバックドアに備えられる撮像部１２１０４は、主として車両１２１００の後方の画像を取得する。撮像部１２１０１及び１２１０５で取得される前方の画像は、主として先行車両又は、歩行者、障害物、信号機、交通標識又は車線等の検出に用いられる。 The imaging units 12101, 12102, 12103, 12104, and 12105 are provided, for example, at positions such as the front nose, side mirrors, rear bumper, back door, and the top of the windshield inside the vehicle 12100. An imaging unit 12101 provided in the front nose and an imaging unit 12105 provided above the windshield inside the vehicle mainly acquire images in front of the vehicle 12100. Imaging units 12102 and 12103 provided in the side mirrors mainly capture images of the sides of the vehicle 12100. An imaging unit 12104 provided in the rear bumper or back door mainly captures images of the rear of the vehicle 12100. The images of the front acquired by the imaging units 12101 and 12105 are mainly used for detecting preceding vehicles, pedestrians, obstacles, traffic lights, traffic signs, lanes, and the like.
　なお、図１２には、撮像部１２１０１ないし１２１０４の撮影範囲の一例が示されている。撮像範囲１２１１１は、フロントノーズに設けられた撮像部１２１０１の撮像範囲を示し、撮像範囲１２１１２，１２１１３は、それぞれサイドミラーに設けられた撮像部１２１０２，１２１０３の撮像範囲を示し、撮像範囲１２１１４は、リアバンパ又はバックドアに設けられた撮像部１２１０４の撮像範囲を示す。例えば、撮像部１２１０１ないし１２１０４で撮像された画像データが重ね合わせられることにより、車両１２１００を上方から見た俯瞰画像が得られる。 Note that FIG. 12 shows an example of the imaging range of the imaging units 12101 to 12104. An imaging range 12111 indicates the imaging range of the imaging unit 12101 provided on the front nose, imaging ranges 12112 and 12113 indicate imaging ranges of the imaging units 12102 and 12103 provided on the side mirrors, respectively, and an imaging range 12114 shows the imaging range of the imaging unit 12101 provided on the front nose. The imaging range of the imaging unit 12104 provided in the rear bumper or back door is shown. For example, by overlapping the image data captured by the imaging units 12101 to 12104, an overhead image of the vehicle 12100 viewed from above can be obtained.
　撮像部１２１０１ないし１２１０４の少なくとも１つは、距離情報を取得する機能を有していてもよい。例えば、撮像部１２１０１ないし１２１０４の少なくとも１つは、複数の撮像素子からなるステレオカメラであってもよいし、位相差検出用の画素を有する撮像素子であってもよい。 At least one of the imaging units 12101 to 12104 may have a function of acquiring distance information. For example, at least one of the imaging units 12101 to 12104 may be a stereo camera including a plurality of image sensors, or may be an image sensor having pixels for phase difference detection.
　例えば、マイクロコンピュータ１２０５１は、撮像部１２１０１ないし１２１０４から得られた距離情報を基に、撮像範囲１２１１１ないし１２１１４内における各立体物までの距離と、この距離の時間的変化（車両１２１００に対する相対速度）を求めることにより、特に車両１２１００の進行路上にある最も近い立体物で、車両１２１００と略同じ方向に所定の速度（例えば、０ｋｍ／ｈ以上）で走行する立体物を先行車として抽出することができる。さらに、マイクロコンピュータ１２０５１は、先行車の手前に予め確保すべき車間距離を設定し、自動ブレーキ制御（追従停止制御も含む）や自動加速制御（追従発進制御も含む）等を行うことができる。このように運転者の操作に拠らずに自律的に走行する自動運転等を目的とした協調制御を行うことができる。 For example, the microcomputer 12051 determines the distance to each three-dimensional object within the imaging ranges 12111 to 12114 and the temporal change in this distance (relative speed with respect to the vehicle 12100) based on the distance information obtained from the imaging units 12101 to 12104. In particular, by determining the three-dimensional object that is closest to the vehicle 12100 on its path and that is traveling at a predetermined speed (for example, 0 km/h or more) in approximately the same direction as the vehicle 12100, it is possible to extract the three-dimensional object as the preceding vehicle. can. Furthermore, the microcomputer 12051 can set an inter-vehicle distance to be secured in advance in front of the preceding vehicle, and perform automatic brake control (including follow-up stop control), automatic acceleration control (including follow-up start control), and the like. In this way, it is possible to perform cooperative control for the purpose of autonomous driving, etc., in which the vehicle travels autonomously without depending on the driver's operation.
　例えば、マイクロコンピュータ１２０５１は、撮像部１２１０１ないし１２１０４から得られた距離情報を元に、立体物に関する立体物データを、２輪車、普通車両、大型車両、歩行者、電柱等その他の立体物に分類して抽出し、障害物の自動回避に用いることができる。例えば、マイクロコンピュータ１２０５１は、車両１２１００の周辺の障害物を、車両１２１００のドライバが視認可能な障害物と視認困難な障害物とに識別する。そして、マイクロコンピュータ１２０５１は、各障害物との衝突の危険度を示す衝突リスクを判断し、衝突リスクが設定値以上で衝突可能性がある状況であるときには、オーディオスピーカ１２０６１や表示部１２０６２を介してドライバに警報を出力することや、駆動系制御ユニット１２０１０を介して強制減速や回避操舵を行うことで、衝突回避のための運転支援を行うことができる。 For example, the microcomputer 12051 transfers three-dimensional object data to other three-dimensional objects such as two-wheeled vehicles, regular vehicles, large vehicles, pedestrians, and utility poles based on the distance information obtained from the imaging units 12101 to 12104. It can be classified and extracted and used for automatic obstacle avoidance. For example, the microcomputer 12051 identifies obstacles around the vehicle 12100 into obstacles that are visible to the driver of the vehicle 12100 and obstacles that are difficult to see. Then, the microcomputer 12051 determines a collision risk indicating the degree of risk of collision with each obstacle, and when the collision risk exceeds a set value and there is a possibility of a collision, the microcomputer 12051 transmits information via the audio speaker 12061 and the display unit 12062. By outputting a warning to the driver via the vehicle control unit 12010 and performing forced deceleration and avoidance steering via the drive system control unit 12010, driving support for collision avoidance can be provided.
　撮像部１２１０１ないし１２１０４の少なくとも１つは、赤外線を検出する赤外線カメラであってもよい。例えば、マイクロコンピュータ１２０５１は、撮像部１２１０１ないし１２１０４の撮像画像中に歩行者が存在するか否かを判定することで歩行者を認識することができる。かかる歩行者の認識は、例えば赤外線カメラとしての撮像部１２１０１ないし１２１０４の撮像画像における特徴点を抽出する手順と、物体の輪郭を示す一連の特徴点にパターンマッチング処理を行って歩行者か否かを判別する手順によって行われる。マイクロコンピュータ１２０５１が、撮像部１２１０１ないし１２１０４の撮像画像中に歩行者が存在すると判定し、歩行者を認識すると、音声画像出力部１２０５２は、当該認識された歩行者に強調のための方形輪郭線を重畳表示するように、表示部１２０６２を制御する。また、音声画像出力部１２０５２は、歩行者を示すアイコン等を所望の位置に表示するように表示部１２０６２を制御してもよい。 At least one of the imaging units 12101 to 12104 may be an infrared camera that detects infrared rays. For example, the microcomputer 12051 can recognize a pedestrian by determining whether the pedestrian is present in the images captured by the imaging units 12101 to 12104. Such pedestrian recognition involves, for example, a procedure for extracting feature points in images captured by the imaging units 12101 to 12104 as infrared cameras, and a pattern matching process is performed on a series of feature points indicating the outline of an object to determine whether it is a pedestrian or not. This is done through a procedure that determines the When the microcomputer 12051 determines that a pedestrian is present in the images captured by the imaging units 12101 to 12104 and recognizes the pedestrian, the audio image output unit 12052 creates a rectangular outline for emphasis on the recognized pedestrian. The display unit 12062 is controlled to display the . Furthermore, the audio image output unit 12052 may control the display unit 12062 to display an icon or the like indicating a pedestrian at a desired position.
　以上、本開示に係る技術が適用され得る車両制御システムの一例について説明した。本開示に係る技術は、以上説明した構成のうち、例えば、撮像部１２０３１に適用され得る。具体的には、撮像部１２０３１とともに、本開示による光源装置１を設ければよい。撮像部１２０３１に、本開示に係る技術を適用することにより、レーザ光のピークパワーを可変にすることができ、車両制御システムの機能性および安全性を高めることができる。 An example of a vehicle control system to which the technology according to the present disclosure can be applied has been described above. The technology according to the present disclosure can be applied to, for example, the imaging unit 12031 among the configurations described above. Specifically, the light source device 1 according to the present disclosure may be provided together with the imaging section 12031. By applying the technology according to the present disclosure to the imaging unit 12031, the peak power of the laser light can be made variable, and the functionality and safety of the vehicle control system can be improved.
　なお、本技術は以下のような構成を取ることができる。
　（１）駆動条件に応じて変化する波長である第１波長の光を出射する活性層と、前記第１波長に対する第１反射層と、を有する積層半導体層と、
　前記積層半導体層の光出射面に対向する第１面に配置される第２波長に対する第２反射層と、
　前記第１面よりも光軸の後方側に配置される第２面に配置され、前記第１波長に対する第３反射層と、
　前記第２反射層及び前記第３反射層の間に配置されるレーザ媒質と、　前記第２面に配置されるか、又は前記第２面より光軸の後方側に配置される、前記第２波長に対する第４反射層と、
　前記第１反射層及び前記第３反射層の間で前記第１波長の光を共振させる第１共振器と、
を備え、
　前記積層半導体層の光軸及び前記レーザ媒質の光軸は、一軸上に配置される、
光源装置。
　（２）前記駆動条件は、前記活性層に注入される駆動電流又は前記活性層の温度の少なくとも一方を含む、
（１）に記載の光源装置。
　（３）前記活性層は、前記駆動電流に応じて、それぞれ波長が異なる少なくとも２種類の前記第１波長のいずれかの光を出射し、
　前記第３反射層は、前記少なくとも２種類の第１波長に対してそれぞれ異なる反射率を有する、
（２）に記載の光源装置。
　（４）前記活性層は、前記駆動電流が大きいほど、より長い前記第１波長の光を出射し、
　前記第３反射層は、前記第１波長が長いほど、反射率をより高くする、
（２）又は（３）に記載の光源装置。
　（５）前記活性層は、前記駆動電流が大きいほど、より長い前記第１波長の光を出射し、
　前記第３反射層は、前記第１波長が長いほど、反射率をより低くする、
（２）又は（３）に記載の光源装置。
　（６）前記第１波長は、前記活性層に第１駆動電流を流すときに出射される第３波長と、前記活性層に第２駆動電流を流すときに出射される第４波長とを含み、
　前記第３反射層は、前記第３波長及び前記第４波長に対して、互いに異なる反射率を有する、
（２）又は（３）に記載の光源装置。
　（７）前記第３反射層は、前記第３波長に対する反射率よりも、前記第４波長に対する反射率が高く、
　前記レーザ媒質は、前記第３波長に対しては前記第２波長を励起させず、前記第４波長に対しては前記第２波長を励起させる、
（６）に記載の光源装置。
　（８）前記第３反射層は、前記第３波長に対する反射率よりも、前記第４波長に対する反射率が低く、
　前記レーザ媒質は、前記第４波長に対しては前記第２波長を励起させず、前記第３波長に対しては前記第２波長を励起させる、
（６）に記載の光源装置。
　（９）前記第１駆動電流は、前記第２駆動電流よりも小さく、
　前記第３波長は、前記第４波長よりも短い、
（６）乃至（８）のいずれか一項に記載の光源装置。
　（１０）前記積層半導体層は、それぞれ異なる前記第１波長の光を出射する複数の第１領域を有し、
　前記第３反射層は、前記複数の第１領域に対応して設けられ、前記第１波長に対してそれぞれ異なる反射率を有する複数の第２領域を有する、
（１）乃至（９）のいずれか一項に記載の光源装置。
　（１１）前記積層半導体層は、前記第３波長又は前記第４波長の光を出射する複数の第１領域を有し、
　前記第３反射層は、前記複数の第１領域に対応して設けられ、前記第３波長及び前記第４波長に対して互いに異なる反射率を持つ複数の第２領域を有する、
（６）乃至（９）のいずれか一項に記載の光源装置。
　（１２）前記積層半導体層は、前記第１波長の光を間欠的に出射する、
（１）乃至（９）のいずれか一項に記載の光源装置。
　（１３）前記第２反射層及び前記第４反射層の間で前記第２波長の光を共振させる第２共振器をさらに備える、
（１）乃至（１２）のいずれか一項に記載の光源装置。
　（１４）前記第４反射層を有する可飽和吸収体をさらに備え、
　前記積層半導体層の光軸、前記レーザ媒質の光軸、前記可飽和吸収体の光軸は、一軸上に配置される、
（１）乃至（１３）のいずれか一項に記載の光源装置。
　（１５）前記第２波長の光は、前記第１波長の光より大きいピークパワーを有する、
（１４）に記載の光源装置。
　（１６）前記第４反射層は、前記第２波長の、Ｑスイッチパルス波光を出射する、
（１４）又は（１５）に記載の光源装置。
　（１７）波長を切り替えて発光可能な光源装置と、
　受光部と、
　前記光源装置の発光信号が対象物で反射されて前記受光部で受光されたときに、前記発光信号と前記受光部の受光信号とに基づいて前記対象物までの距離を計測する距離計測部と、を備え、
　前記光源装置は、
　駆動条件に応じて変化する波長である第１波長の光を出射する活性層と、前記第１波長に対する第１反射層と、を有する積層半導体層と、
　前記積層半導体層の光出射面に対向する第１面に配置される第２波長に対する第２反射層と、
　前記第１面よりも光軸の後方側に配置される第２面に配置され、前記第１波長に対する第３反射層と、
　前記第２反射層及び前記第３反射層の間に配置されるレーザ媒質と、　前記第２面に配置されるか、又は前記第２面より光軸の後方側に配置される、前記第２波長に対する第４反射層と、
　前記第１反射層及び前記第３反射層の間で前記第１波長の光を共振させる第１共振器と、
　前記第２反射層及び前記第４反射層の間で前記第２波長の光を共振させる第２共振器と、
を備え、
　前記積層半導体層の光軸及び前記レーザ媒質の光軸は、一軸上に配置される、測距装置。
　（１８）前記対象物までの距離に応じて前記駆動条件を制御する駆動部を備える、
（１７）に記載の測距装置。
　（１９）前記駆動部は、前記対象物の距離に応じて、前記光源装置から出射される前記発光信号のピークパワーを切替制御する、
（１８）に記載の測距装置。
　（２０）波長を切り替えて発光可能な光源装置の発光信号が対象物で反射されて受光部で受光されたときに、前記発光信号と前記受光部の受光信号とに基づいて対象物までの距離を計測し、
　前記光源装置は、
　駆動条件に応じて変化する波長である第１波長の光を出射する活性層と、前記第１波長に対する第１反射層と、を有する積層半導体層と、
　前記積層半導体層の光出射面に対向する第１面に配置される第２波長に対する第２反射層と、
　前記第１面よりも光軸の後方側に配置される第２面に配置され、前記第１波長に対する第３反射層と、
　前記第２反射層及び前記第３反射層の間に配置されるレーザ媒質と、　前記第２面に配置されるか、又は前記第２面より光軸の後方側に配置される、前記第２波長に対する第４反射層と、
　前記第１反射層及び前記第３反射層の間で前記第１波長の光を共振させる第１共振器と、
　前記第２反射層及び前記第４反射層の間で前記第２波長の光を共振させる第２共振器と、を積層して形成され、
　前記積層半導体層の光軸及び前記レーザ媒質の光軸は、一軸上に配置される、
測距方法。 Note that the present technology can have the following configuration.
(1) a laminated semiconductor layer having an active layer that emits light of a first wavelength that changes depending on driving conditions; and a first reflective layer for the first wavelength;
a second reflective layer for a second wavelength disposed on a first surface facing the light emitting surface of the laminated semiconductor layer;
a third reflective layer for the first wavelength, disposed on a second surface disposed on the rear side of the optical axis from the first surface;
a laser medium disposed between the second reflective layer and the third reflective layer; and a laser medium disposed on the second surface or on the rear side of the optical axis from the second surface. a fourth reflective layer for wavelength;
a first resonator that causes light of the first wavelength to resonate between the first reflective layer and the third reflective layer;
Equipped with
The optical axis of the laminated semiconductor layer and the optical axis of the laser medium are arranged on one axis,
Light source device.
(2) The driving condition includes at least one of a driving current injected into the active layer or a temperature of the active layer.
The light source device according to (1).
(3) the active layer emits light of at least two types of the first wavelength, each having a different wavelength, depending on the drive current;
The third reflective layer has different reflectances for the at least two types of first wavelengths,
The light source device according to (2).
(4) the active layer emits the longer light of the first wavelength as the drive current is larger;
The third reflective layer has a higher reflectance as the first wavelength is longer.
The light source device according to (2) or (3).
(5) The active layer emits the longer light of the first wavelength as the drive current is larger;
The third reflective layer has a lower reflectance as the first wavelength is longer.
The light source device according to (2) or (3).
(6) The first wavelength includes a third wavelength emitted when the first drive current is passed through the active layer, and a fourth wavelength emitted when the second drive current is passed through the active layer. ,
The third reflective layer has different reflectances for the third wavelength and the fourth wavelength,
The light source device according to (2) or (3).
(7) the third reflective layer has a higher reflectance for the fourth wavelength than for the third wavelength;
The laser medium does not excite the second wavelength with respect to the third wavelength, and excites the second wavelength with respect to the fourth wavelength.
The light source device according to (6).
(8) the third reflective layer has a lower reflectance for the fourth wavelength than for the third wavelength;
The laser medium does not excite the second wavelength with respect to the fourth wavelength, and excites the second wavelength with respect to the third wavelength.
The light source device according to (6).
(9) the first drive current is smaller than the second drive current;
the third wavelength is shorter than the fourth wavelength,
The light source device according to any one of (6) to (8).
(10) The laminated semiconductor layer has a plurality of first regions that each emit light of a different first wavelength,
The third reflective layer is provided corresponding to the plurality of first regions, and has a plurality of second regions each having a different reflectance with respect to the first wavelength.
The light source device according to any one of (1) to (9).
(11) The laminated semiconductor layer has a plurality of first regions that emit light of the third wavelength or the fourth wavelength,
The third reflective layer is provided corresponding to the plurality of first regions, and has a plurality of second regions having mutually different reflectances with respect to the third wavelength and the fourth wavelength.
The light source device according to any one of (6) to (9).
(12) the laminated semiconductor layer intermittently emits light of the first wavelength;
The light source device according to any one of (1) to (9).
(13) further comprising a second resonator that causes the light of the second wavelength to resonate between the second reflective layer and the fourth reflective layer;
The light source device according to any one of (1) to (12).
(14) further comprising a saturable absorber having the fourth reflective layer,
The optical axis of the laminated semiconductor layer, the optical axis of the laser medium, and the optical axis of the saturable absorber are arranged on one axis,
The light source device according to any one of (1) to (13).
(15) The light at the second wavelength has a larger peak power than the light at the first wavelength.
The light source device according to (14).
(16) the fourth reflective layer emits Q-switched pulsed wave light of the second wavelength;
The light source device according to (14) or (15).
(17) A light source device capable of emitting light by switching the wavelength;
A light receiving section,
a distance measuring unit that measures the distance to the target object based on the light emission signal and the light reception signal of the light reception unit when the light emission signal of the light source device is reflected by the target object and received by the light reception unit; , comprising:
The light source device includes:
a laminated semiconductor layer having an active layer that emits light of a first wavelength that changes depending on driving conditions; and a first reflective layer for the first wavelength;
a second reflective layer for a second wavelength disposed on a first surface facing the light emitting surface of the laminated semiconductor layer;
a third reflective layer for the first wavelength, disposed on a second surface disposed on the rear side of the optical axis from the first surface;
a laser medium disposed between the second reflective layer and the third reflective layer; and a laser medium disposed on the second surface or on the rear side of the optical axis from the second surface. a fourth reflective layer for wavelength;
a first resonator that causes light of the first wavelength to resonate between the first reflective layer and the third reflective layer;
a second resonator that causes light of the second wavelength to resonate between the second reflective layer and the fourth reflective layer;
Equipped with
In the distance measuring device, an optical axis of the laminated semiconductor layer and an optical axis of the laser medium are arranged on one axis.
(18) comprising a drive unit that controls the drive conditions according to the distance to the target object;
The distance measuring device according to (17).
(19) The drive unit switches and controls the peak power of the light emission signal emitted from the light source device according to the distance of the target object.
The distance measuring device according to (18).
(20) When a light emission signal from a light source device capable of emitting light by switching the wavelength is reflected by an object and received by a light receiving section, the distance to the object is determined based on the light emission signal and the light reception signal of the light receiving section. Measure the
The light source device includes:
a laminated semiconductor layer having an active layer that emits light of a first wavelength that changes depending on driving conditions; and a first reflective layer for the first wavelength;
a second reflective layer for a second wavelength disposed on a first surface facing the light emitting surface of the laminated semiconductor layer;
a third reflective layer for the first wavelength, disposed on a second surface disposed on the rear side of the optical axis from the first surface;
a laser medium disposed between the second reflective layer and the third reflective layer; and a laser medium disposed on the second surface or on the rear side of the optical axis from the second surface. a fourth reflective layer for wavelength;
a first resonator that causes light of the first wavelength to resonate between the first reflective layer and the third reflective layer;
a second resonator that resonates light of the second wavelength between the second reflective layer and the fourth reflective layer;
The optical axis of the laminated semiconductor layer and the optical axis of the laser medium are arranged on one axis,
Distance measurement method.
　本開示の態様は、上述した個々の実施形態に限定されるものではなく、当業者が想到しうる種々の変形も含むものであり、本開示の効果も上述した内容に限定されない。すなわち、特許請求の範囲に規定された内容およびその均等物から導き出される本開示の概念的な思想と趣旨を逸脱しない範囲で種々の追加、変更および部分的削除が可能である。 Aspects of the present disclosure are not limited to the individual embodiments described above, and include various modifications that can be thought of by those skilled in the art, and the effects of the present disclosure are not limited to the contents described above. That is, various additions, changes, and partial deletions are possible without departing from the conceptual idea and spirit of the present disclosure derived from the content defined in the claims and equivalents thereof.
　１　光源装置、２　励起光源、３　レーザ媒質、４　可飽和吸収体、５　支持体、１１　第１共振器、１２　第２共振器、２１　基板、２２、２４　クラッド層、２３　活性層、２５　コンタクト層、５１　マウント部材、５２　サブマウント部材、５３ａ、５３ｂ　配線層、５４ａ、５４ｂ　ピン、５５ａ、５５ｂ　ワイヤ、５６ａ、５６ｂ　半田層、５７、５８　導電層、５９ａ、５９ｂ　絶縁層、６０　測距装置、６１　発光部、６２　駆動部、６３　電源回路、６４　発光側光学系、６５　受光側光学系、６６　受光部、６７　信号処理部、６８　制御部、６８ａ　測距部、６９　温度検出部 1 light source device, 2 excitation light source, 3 laser medium, 4 saturable absorber, 5 support, 11 first resonator, 12 second resonator, 21 substrate, 22, 24 cladding layer, 23 active layer, 25 contact layer , 51 Mount member, 52 Submount member, 53a, 53b Wiring layer, 54a, 54b Pin, 55a, 55b Wire, 56a, 56b Solder layer, 57, 58 Conductive layer, 59a, 59b Insulating layer, 60 Distance measuring device, 61 Light emitting unit, 62 Drive unit, 63 Power supply circuit, 64 Light emitting side optical system, 65 Light receiving side optical system, 66 Light receiving unit, 67 Signal processing unit, 68 Control unit, 68a Distance measuring unit, 69 Temperature detection unit

Claims (20)

  1. 　駆動条件に応じて変化する波長である第１波長の光を出射する活性層と、前記第１波長に対する第１反射層と、を有する積層半導体層と、
    　前記積層半導体層の光出射面に対向する第１面に配置される第２波長に対する第２反射層と、
    　前記第１面よりも光軸の後方側に配置される第２面に配置され、前記第１波長に対する第３反射層と、
    　前記第２反射層及び前記第３反射層の間に配置されるレーザ媒質と、
    　前記第２面に配置されるか、又は前記第２面より光軸の後方側に配置される、前記第２波長に対する第４反射層と、
    　前記第１反射層及び前記第３反射層の間で前記第１波長の光を共振させる第１共振器と、
    を備え、
    　前記積層半導体層の光軸及び前記レーザ媒質の光軸は、一軸上に配置される、
    光源装置。     a laminated semiconductor layer having an active layer that emits light of a first wavelength that changes depending on driving conditions; and a first reflective layer for the first wavelength;
    a second reflective layer for a second wavelength disposed on a first surface facing the light emitting surface of the laminated semiconductor layer;
    a third reflective layer for the first wavelength, disposed on a second surface disposed on the rear side of the optical axis from the first surface;
    a laser medium disposed between the second reflective layer and the third reflective layer;
    a fourth reflective layer for the second wavelength, disposed on the second surface or disposed on the rear side of the optical axis from the second surface;
    a first resonator that causes light of the first wavelength to resonate between the first reflective layer and the third reflective layer;
    Equipped with
    The optical axis of the laminated semiconductor layer and the optical axis of the laser medium are arranged on one axis,
    Light source device.
  2. 　前記駆動条件は、前記活性層に注入される駆動電流又は前記活性層の温度の少なくとも一方を含む、
    請求項１に記載の光源装置。     The driving condition includes at least one of a driving current injected into the active layer and a temperature of the active layer.
    The light source device according to claim 1.
  3. 　前記活性層は、前記駆動電流に応じて、それぞれ波長が異なる少なくとも２種類の前記第１波長のいずれかの光を出射し、
    　前記第３反射層は、前記少なくとも２種類の第１波長に対してそれぞれ異なる反射率を有する、
    請求項２に記載の光源装置。     The active layer emits one of at least two types of light having the first wavelength, each of which has a different wavelength, depending on the drive current,
    The third reflective layer has different reflectances for the at least two types of first wavelengths,
    The light source device according to claim 2.
  4. 　前記活性層は、前記駆動電流が大きいほど、より長い前記第１波長の光を出射し、
    　前記第３反射層は、前記第１波長が長いほど、反射率をより高くする、
    請求項２に記載の光源装置。     The active layer emits the longer light of the first wavelength as the drive current is larger,
    The third reflective layer has a higher reflectance as the first wavelength is longer.
    The light source device according to claim 2.
  5. 　前記活性層は、前記駆動電流が大きいほど、より長い前記第１波長の光を出射し、
    　前記第３反射層は、前記第１波長が長いほど、反射率をより低くする、
    請求項２に記載の光源装置。     The active layer emits the longer light of the first wavelength as the drive current is larger,
    The third reflective layer has a lower reflectance as the first wavelength is longer.
    The light source device according to claim 2.
  6. 　前記第１波長は、前記活性層に第１駆動電流を流すときに出射される第３波長と、前記活性層に第２駆動電流を流すときに出射される第４波長とを含み、
    　前記第３反射層は、前記第３波長及び前記第４波長に対して、互いに異なる反射率を有する、
    請求項２に記載の光源装置。     The first wavelength includes a third wavelength emitted when a first drive current is passed through the active layer, and a fourth wavelength emitted when a second drive current is passed through the active layer,
    The third reflective layer has different reflectances for the third wavelength and the fourth wavelength,
    The light source device according to claim 2.
  7. 　前記第３反射層は、前記第３波長に対する反射率よりも、前記第４波長に対する反射率が高く、
    　前記レーザ媒質は、前記第３波長に対しては前記第２波長を励起させず、前記第４波長に対しては前記第２波長を励起させる、
    請求項６に記載の光源装置。     The third reflective layer has a higher reflectance for the fourth wavelength than a reflectance for the third wavelength,
    The laser medium does not excite the second wavelength with respect to the third wavelength, and excites the second wavelength with respect to the fourth wavelength.
    The light source device according to claim 6.
  8. 　前記第３反射層は、前記第３波長に対する反射率よりも、前記第４波長に対する反射率が低く、
    　前記レーザ媒質は、前記第４波長に対しては前記第２波長を励起させず、前記第３波長に対しては前記第２波長を励起させる、
    請求項６に記載の光源装置。     The third reflective layer has a lower reflectance for the fourth wavelength than a reflectance for the third wavelength,
    The laser medium does not excite the second wavelength with respect to the fourth wavelength, and excites the second wavelength with respect to the third wavelength.
    The light source device according to claim 6.
  9. 　前記第１駆動電流は、前記第２駆動電流よりも小さく、
    　前記第３波長は、前記第４波長よりも短い、
    請求項６に記載の光源装置。     the first drive current is smaller than the second drive current,
    the third wavelength is shorter than the fourth wavelength,
    The light source device according to claim 6.
  10. 　前記積層半導体層は、それぞれ異なる前記第１波長の光を出射する複数の第１領域を有し、
    　前記第３反射層は、前記複数の第１領域に対応して設けられ、前記第１波長に対してそれぞれ異なる反射率を有する複数の第２領域を有する、
    請求項１に記載の光源装置。     The laminated semiconductor layer has a plurality of first regions that each emit light of a different first wavelength,
    The third reflective layer is provided corresponding to the plurality of first regions, and has a plurality of second regions each having a different reflectance with respect to the first wavelength.
    The light source device according to claim 1.
  11. 　前記積層半導体層は、前記第３波長又は前記第４波長の光を出射する複数の第１領域を有し、
    　前記第３反射層は、前記複数の第１領域に対応して設けられ、前記第３波長及び前記第４波長に対して互いに異なる反射率を持つ複数の第２領域を有する、
    請求項６に記載の光源装置。     The laminated semiconductor layer has a plurality of first regions that emit light of the third wavelength or the fourth wavelength,
    The third reflective layer is provided corresponding to the plurality of first regions, and has a plurality of second regions having mutually different reflectances with respect to the third wavelength and the fourth wavelength.
    The light source device according to claim 6.
  12. 　前記積層半導体層は、前記第１波長の光を間欠的に出射する、
    請求項１に記載の光源装置。     the laminated semiconductor layer intermittently emits light of the first wavelength;
    The light source device according to claim 1.
  13. 　前記第２反射層及び前記第４反射層の間で前記第２波長の光を共振させる第２共振器をさらに備える、
    請求項１に記載の光源装置。     further comprising a second resonator that causes light of the second wavelength to resonate between the second reflective layer and the fourth reflective layer;
    The light source device according to claim 1.
  14. 　前記第４反射層を有する可飽和吸収体をさらに備え、
    　前記積層半導体層の光軸、前記レーザ媒質の光軸、前記可飽和吸収体の光軸は、一軸上に配置される、
    請求項１３に記載の光源装置。     further comprising a saturable absorber having the fourth reflective layer,
    The optical axis of the laminated semiconductor layer, the optical axis of the laser medium, and the optical axis of the saturable absorber are arranged on one axis,
    The light source device according to claim 13.
  15. 　前記第２波長の光は、前記第１波長の光より大きいピークパワーを有する、
    請求項１４に記載の光源装置。     The light at the second wavelength has a larger peak power than the light at the first wavelength.
    The light source device according to claim 14.
  16. 　前記第４反射層は、前記第２波長の、Ｑスイッチパルス波光を出射する、
    請求項１４に記載の光源装置。     the fourth reflective layer emits Q-switched pulsed wave light of the second wavelength;
    The light source device according to claim 14.
  17. 　波長を切り替えて発光可能な光源装置と、
    　受光部と、
    　前記光源装置の発光信号が対象物で反射されて前記受光部で受光されたときに、前記発光信号と前記受光部の受光信号とに基づいて前記対象物までの距離を計測する距離計測部と、を備え、
    　前記光源装置は、
    　駆動条件に応じて変化する波長である第１波長の光を出射する活性層と、前記第１波長に対する第１反射層と、を有する積層半導体層と、
    　前記積層半導体層の光出射面に対向する第１面に配置される第２波長に対する第２反射層と、
    　前記第１面よりも光軸の後方側に配置される第２面に配置され、前記第１波長に対する第３反射層と、
    　前記第２反射層及び前記第３反射層の間に配置されるレーザ媒質と、
    　前記第２面に配置されるか、又は前記第２面より光軸の後方側に配置される、前記第２波長に対する第４反射層と、
    　前記第１反射層及び前記第３反射層の間で前記第１波長の光を共振させる第１共振器と、
    　前記第２反射層及び前記第４反射層の間で前記第２波長の光を共振させる第２共振器と、
    を備え、
    　前記積層半導体層の光軸及び前記レーザ媒質の光軸は、一軸上に配置される、
    測距装置。     A light source device that can emit light by switching the wavelength,
    A light receiving part,
    a distance measuring unit that measures the distance to the target object based on the light emission signal and the light reception signal of the light reception unit when the light emission signal of the light source device is reflected by the target object and received by the light reception unit; , comprising;
    The light source device includes:
    a laminated semiconductor layer having an active layer that emits light of a first wavelength that changes depending on driving conditions; and a first reflective layer for the first wavelength;
    a second reflective layer for a second wavelength disposed on a first surface facing the light emitting surface of the laminated semiconductor layer;
    a third reflective layer for the first wavelength, disposed on a second surface disposed on the rear side of the optical axis from the first surface;
    a laser medium disposed between the second reflective layer and the third reflective layer;
    a fourth reflective layer for the second wavelength, disposed on the second surface or disposed on the rear side of the optical axis from the second surface;
    a first resonator that causes light of the first wavelength to resonate between the first reflective layer and the third reflective layer;
    a second resonator that causes light of the second wavelength to resonate between the second reflective layer and the fourth reflective layer;
    Equipped with
    The optical axis of the laminated semiconductor layer and the optical axis of the laser medium are arranged on one axis,
    Ranging device.
  18. 　前記対象物までの距離に応じて前記駆動条件を制御する駆動部を備える、
    請求項１７に記載の測距装置。     comprising a drive unit that controls the drive conditions according to the distance to the target object;
    The distance measuring device according to claim 17.
  19. 　前記駆動部は、前記対象物の距離に応じて、前記光源装置から出射される前記発光信号のピークパワーを切替制御する、
    請求項１８に記載の測距装置。     The drive unit switches and controls the peak power of the light emission signal emitted from the light source device according to the distance of the target object.
    The distance measuring device according to claim 18.
  20. 　波長を切り替えて発光可能な光源装置の発光信号が対象物で反射されて受光部で受光されたときに、前記発光信号と前記受光部の受光信号とに基づいて対象物までの距離を計測し、
    　前記光源装置は、
    　駆動条件に応じて変化する波長である第１波長の光を出射する活性層と、前記第１波長に対する第１反射層と、を有する積層半導体層と、
    　前記積層半導体層の光出射面に対向する第１面に配置される第２波長に対する第２反射層と、
    　前記第１面よりも光軸の後方側に配置される第２面に配置され、前記第１波長に対する第３反射層と、
    　前記第２反射層及び前記第３反射層の間に配置されるレーザ媒質と、
    　前記第２面に配置されるか、又は前記第２面より光軸の後方側に配置される、前記第２波長に対する第４反射層と、
    　前記第１反射層及び前記第３反射層の間で前記第１波長の光を共振させる第１共振器と、
    　前記第２反射層及び前記第４反射層の間で前記第２波長の光を共振させる第２共振器と、を積層して形成され、
    　前記積層半導体層の光軸及び前記レーザ媒質の光軸は、一軸上に配置される、
    測距方法。     When a light emitting signal from a light source device capable of emitting light by switching the wavelength is reflected by a target object and received by a light receiving section, the distance to the target object is measured based on the light emitting signal and the light receiving signal of the light receiving section. ,
    The light source device includes:
    a laminated semiconductor layer having an active layer that emits light of a first wavelength that changes depending on driving conditions; and a first reflective layer for the first wavelength;
    a second reflective layer for a second wavelength disposed on a first surface facing the light emitting surface of the laminated semiconductor layer;
    a third reflective layer for the first wavelength, disposed on a second surface disposed on the rear side of the optical axis from the first surface;
    a laser medium disposed between the second reflective layer and the third reflective layer;
    a fourth reflective layer for the second wavelength, disposed on the second surface or disposed on the rear side of the optical axis from the second surface;
    a first resonator that causes light of the first wavelength to resonate between the first reflective layer and the third reflective layer;
    a second resonator that resonates light of the second wavelength between the second reflective layer and the fourth reflective layer,
    The optical axis of the laminated semiconductor layer and the optical axis of the laser medium are arranged on one axis,
    Distance measurement method.
PCT/JP2023/029829 2022-08-31 2023-08-18 Light source device, ranging device, and ranging method WO2024048325A1 (en)

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Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2010085316A (en) * 2008-10-01 2010-04-15 Topcon Corp Laser apparatus and distance measuring device
CN102244356A (en) * 2011-05-25 2011-11-16 中国工程物理研究院应用电子学研究所 Double-wavelength quick-switching Q-switched laser device
WO2021106757A1 (en) * 2019-11-28 2021-06-03 ソニー株式会社 Laser element, method for manufacturing laser element, laser device, and laser amplification element

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2010085316A (en) * 2008-10-01 2010-04-15 Topcon Corp Laser apparatus and distance measuring device
CN102244356A (en) * 2011-05-25 2011-11-16 中国工程物理研究院应用电子学研究所 Double-wavelength quick-switching Q-switched laser device
WO2021106757A1 (en) * 2019-11-28 2021-06-03 ソニー株式会社 Laser element, method for manufacturing laser element, laser device, and laser amplification element

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