CN214427670U - Lens system, imaging module and depth camera - Google Patents
Lens system, imaging module and depth camera Download PDFInfo
- Publication number
- CN214427670U CN214427670U CN202120788328.XU CN202120788328U CN214427670U CN 214427670 U CN214427670 U CN 214427670U CN 202120788328 U CN202120788328 U CN 202120788328U CN 214427670 U CN214427670 U CN 214427670U
- Authority
- CN
- China
- Prior art keywords
- lens
- imaging module
- lens system
- focal length
- image
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Active
Links
Images
Landscapes
- Lenses (AREA)
Abstract
The utility model discloses a lens system, formation of image module and degree of depth camera, include: the first lens, the second lens and the third lens are sequentially arranged along the incident direction of the light beam; wherein object side surfaces of the first and third lenses are convex at a paraxial region and image side surfaces of the first and third lenses are concave at a paraxial region; the object-side surface of the second lens element is concave at the paraxial region and the image-side surface is convex at the paraxial region; the first lens and the second lens have positive optical power, and the third lens has negative optical power. The utility model discloses can realize the distortion compensation of big light ring, solve the inhomogeneous problem of imaging module speckle density, can obtain good imaging quality when guaranteeing compact structure.
Description
Technical Field
The utility model relates to an optics and electron technical field, concretely relates to lens system, imaging module and degree of depth camera.
Background
In recent years, with consumer-grade 3D imaging electronics, such as: with the development of structured light cameras and TOF depth cameras, optical lenses are increasingly widely used.
In the TOF depth camera, light emitted by a light source of the projection module projects a speckle pattern to a target field of view after passing through the lens system and the Diffractive Optical Element (DOE), and the speckle pattern is reflected back to be received by the imaging module, which receives the speckle pattern to generate a depth image containing depth information of a target object. For a speckle light source, because an image speckle field angle (FOV) coverage area is obtained by replicating and expanding a central speckle block by a DOE, when the FOV of the speckle area is increased, a severe distortion phenomenon can be generated, which causes the speckles at the center of a receiving end of an imaging module to be dense and the speckles at corners to be sparse, which finally affects the uniformity of a depth image, and causes the uniformity of the depth image to be poor.
The above background disclosure is only for the purpose of assisting understanding of the inventive concepts and technical solutions of the present invention, and does not necessarily belong to the prior art of the present patent application, and should not be used for evaluating the novelty and inventive step of the present application in the case that there is no clear evidence that the above contents are disclosed at the filing date of the present patent application.
SUMMERY OF THE UTILITY MODEL
The utility model discloses a main aim at overcomes prior art not enough, provides a lens system, formation of image module and degree of depth camera to solve at least one kind problem among the above-mentioned background art problem.
The utility model discloses a reach above-mentioned purpose and propose following technical scheme:
a lens system, comprising: the first lens, the second lens and the third lens are sequentially arranged along the incident direction of the light beam; wherein object side surfaces of the first and third lenses are convex at a paraxial region and image side surfaces of the first and third lenses are concave at a paraxial region; the object-side surface of the second lens element is concave at the paraxial region and the image-side surface is convex at the paraxial region; the first lens and the second lens have positive optical power, and the third lens has negative optical power.
In some embodiments, the first lens, the second lens, and the third lens satisfy the following condition:
0<f1/f2<5；
-1<f2/f3<0；
-1<f12/f3<0；
0<f1/f23<3；
1.52<Nd<1.95；
0<f/TL<1；
wherein f is the effective focal length of the lens system; f. of1Is the effective focal length of the first lens; f. of2Is the effective focal length of the second lens; f. of3Is the effective focal length of the third lens; f. of12Is a combined focal length of the first lens and the second lens; f. of23Is the combined focal length of the second lens and the third lens; n is a radical ofdIs the refractive index of the lens material for D light; TL is the distance from the object-side surface to the image-side surface of the first lens element on the optical axis.
In some embodiments, an aperture stop is further included, the aperture stop being disposed between any two adjacent lenses; or, on the object side of the first lens.
In some embodiments, an aperture value of a lens group constituted by the first lens, the second lens and the third lens satisfies: fno < 1.6.
In some embodiments, the first lens, the second lens, and the third lens are plastic lenses.
In some embodiments, the third lens is a glass lens.
The embodiment of the utility model provides another technical scheme does:
an imaging module, comprising: an image sensor, a filter unit, and a receiving optical element; wherein the receiving optical element is configured to receive at least a portion of the speckle pattern reflected back from the target object and direct the at least a portion of the speckle pattern onto the image sensor; the receiving optical element comprises the lens system of any of the embodiments.
In some embodiments, the filtering unit is an infrared filter for filtering out background light or stray light.
The embodiment of the utility model provides a technical scheme does yet:
a depth camera comprises the imaging module, the projection module, a processor and a substrate; the projection module and the imaging module are arranged on the substrate at a preset baseline distance.
In some embodiments, the projection module includes a light source comprised of one or more lasers for projecting an encoded speckle pattern into a target space; the imaging module collects photons in the speckle pattern reflected by the target object and outputs photon signals; the processor synchronizes the trigger signals of the projection module and the imaging module to calculate the flight time required by the photons from emission to reflection to reception, and the depth information of the target object is obtained.
The utility model discloses technical scheme's beneficial effect is:
compared with the prior art, the utility model discloses lens system, formation of image module and degree of depth camera can realize the distortion compensation of big light ring, have solved the inhomogeneous problem of formation of image module speckle density, can obtain good imaging quality when guaranteeing compact structure.
Drawings
In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings needed to be used in the description of the embodiments or the prior art will be briefly described below, it is obvious that the drawings in the following description are only some embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to these drawings without inventive exercise.
FIG. 1 is a functional block diagram of a depth camera according to an embodiment of the present invention;
FIG. 2 is a schematic structural diagram of a lens system according to another embodiment of the present invention;
fig. 3 is a schematic view of an optical path structure of a lens system according to another embodiment of the present invention.
Detailed Description
In order to make the technical solution of the present invention better understood, the technical solution of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments in the present invention, all other embodiments obtained by a person skilled in the art without creative efforts shall belong to the protection scope of the present invention.
It should be noted that the terms "first," "second," and the like in the description and claims of the present invention and in the drawings described above are used for distinguishing between similar elements and not necessarily for describing a particular sequential or chronological order. It is to be understood that the data so used is interchangeable under appropriate circumstances such that the embodiments of the invention described herein are capable of operation in sequences other than those illustrated or otherwise described herein. Furthermore, unless expressly stated or limited otherwise, the terms "mounted," "connected," "secured," and the like are to be construed broadly and can include, for example, fixedly connected, detachably connected, or integrally formed; can be mechanically or electrically connected; either directly or indirectly through intervening media, either internally or in any other relationship. The specific meaning of the above terms in the present invention can be understood according to specific situations by those skilled in the art.
It will be further understood that the terms "length," "width," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner" and "outer" refer to an orientation or positional relationship as shown in the drawings, which are used for convenience in describing and simplifying the invention, and do not indicate or imply that the referenced device or element must have a particular orientation, be constructed and operated in a particular orientation, and thus, are not to be considered limiting of the invention.
The utility model provides a lens system, formation of image module and degree of depth camera is for understanding, describes degree of depth camera, formation of image module earlier below, explains the lens system again further at last.
Referring to fig. 1, fig. 1 is a schematic view of a depth camera according to an embodiment of the present invention, and a depth camera 100 includes a projection module 10, an imaging module 20, a processor 30, and a bracket (not shown); the projection module 10 and the imaging module 20 are arranged on the substrate at a preset baseline distance; wherein, the projection module 10 includes a light source 101 composed of one or more lasers for projecting the encoded speckle pattern into the target space, and reflecting the encoded speckle pattern back to the imaging module 20 through the target object 40 in the target space; the imaging module 20 includes an image sensor 201 for collecting photons in the reflected speckle pattern and outputting a photon signal; the processor 30 is connected to the projection module 10 and the imaging module 20, and is configured to synchronize the trigger signals of the projection module 10 and the imaging module 20 to calculate a flight time required for receiving the photons from the emitting direction to the reflecting direction, so as to obtain depth information of the target object.
Specifically, the projection module 10 includes a light source 101, an emission optical element 102, a driver 103, and the like. The light source 101 may be a Light Emitting Diode (LED), a Laser Diode (LD), an Edge Emitting Laser (EEL), a Vertical Cavity Surface Emitting Laser (VCSEL), or the like, or may be a one-dimensional or two-dimensional light source array composed of a plurality of light sources. The light beam projected by the light source 111 may be visible light, infrared light, ultraviolet light, or the like. The light source 101 projects a light beam outward under the control of the driver 103. In one embodiment, the light source 101 is an infrared laser light source, such as a 940nm band, the speckle points may be arranged in a quadrilateral or hexagonal pattern, and correspondingly, the imaging module is an infrared camera with a corresponding band.
The emission optical element 102 receives the light beam emitted from the light source 101 and projects the light beam to a target region after shaping. In one embodiment, the transmit optical element 102 receives a pulsed light beam from the light source 101 and modulates the pulsed light beam by encoding, such as diffraction, refraction, reflection, etc., and then projects an encoded speckle pattern, such as a focused light beam, a flood light beam, a structured light beam, etc., into space. In one embodiment, the emitting optical element 102 is a lens or a lens group.
The imaging module 20 includes an image sensor 201, a filter unit 202, and a receiving optical element 203; wherein receiving optics 203 is configured to receive at least a portion of the speckle pattern reflected back from the target object and direct the at least a portion of the speckle pattern onto image sensor 201; the filtering unit 202 is used for filtering out background light or stray light. In one embodiment, the image sensor 201 is a TOF sensor, the filter unit 202 is a filter (e.g., an infrared filter), and the receiving optics 203 includes a lens system.
Referring to fig. 2 and 3, a lens system according to an embodiment of the present invention includes a first lens L1, a second lens L2, and a third lens L3 sequentially arranged along the incident direction of the light beam 205. For convenience of description, the incident surface of the light beam 205 of the lens system is defined as the object surface, the emergent surface of the light beam 205 is the image surface (i.e. the surface close to the filtering unit 202), the object surface of the lens close to the lens system is the object side surface, and the surface close to the image surface is the image side surface. Wherein the object-side surfaces of the first lens element L1 and the third lens element L3 are convex at the paraxial region, and the image-side surfaces of the first lens element L1 and the third lens element L3 are concave at the paraxial region; the object-side surface of the second lens element L2 is concave at the paraxial region, and the image-side surface of the second lens element L2 is convex at the paraxial region; the first lens L1 and the second lens L2 have positive optical power, and the third lens L3 has negative optical power.
As an embodiment of the present invention, the lens system satisfies the following conditions:
0<f1/f2<5；
-1<f2/f3<0；
-1<f12/f3<0；
0<f1/f23<3；
1.52<Nd<1.95；
0<f/TL<1；
wherein f represents the effective focal length of the lens system; f. of1Denotes an effective focal length of the first lens L1; f. of2Denotes a second lens L2The effective focal length of; f. of3Represents the effective focal length of the third lens L3; f. of12Denotes a combined focal length (unit: mm) of the first lens L1 and the second lens L2; f. of23Denotes a combined focal length (unit: mm) of the second lens L2 and the third lens L3; n is a radical ofdRepresenting the refractive index of the lens material for D light. The D light can be written as a D-line, also called a D line, and has the wavelength of 587 nm; TL denotes a distance from the object-side surface to the image-side surface of the first lens L1 on the optical axis.
In some embodiments, the lens system further comprises an aperture stop 204; the aperture stop 204 may be disposed according to the requirement, for example, between any two adjacent lenses, or disposed on the object side of the first lens L1.
In some embodiments, the aperture value of the lens group consisting of the first lens L1, the second lens L2, and the third lens L3 of the lens system is Fno, and Fno <1.6 is satisfied, so that the imaging surface has sufficient and appropriate illuminance.
In one embodiment, all lenses of the lens system are plastic lenses, and the focal length of the lens group is reduced by optimizing system parameters and being affected by temperature over-cooling or over-heating. The plastic lens may be made of PMMA (polymethyl methacrylate, i.e., organic glass, commonly known as acryl), PC (Polycarbonate), and APEL5014 (cyclic olefin copolymer). In some embodiments, to the great imaging module of temperature variation, lens system's lens can adopt the glass material that receives the temperature to influence for a short time, and the glass material can improve thermal stability, and it is high temperature resistant, corrosion-resistant, characteristics such as resistant fish tail, consequently, adopt and receive the glass material that the temperature influence is little can protect whole lens system not by the fish tail in assembly, transportation, the use, difficult quilt of being decomposed by the wind under adverse circumstances such as high temperature, low temperature, high light, sand blown by the wind, destroy to lens system's life has been prolonged. In some embodiments, the third lens L3 may be configured as a glass lens so that the lens system can have stable focal position and focal length at different temperatures, thereby taking into account the performance and cost of the lens system, and the first lens L1 and the second lens L2 are not limited, and glass or plastic may be used.
For convenience of description, the object side of the first lens L1 is denoted as S3; the image-side surface of the first lens L1 is denoted as S4; the object-side surface of the second lens L2 is denoted as S5; the image-side surface of the second lens L2 is denoted by S6; the object-side surface of the third lens L3 is denoted as S7; the image-side surface of the third lens L3 is denoted by S8.
Table 1 below is a parametric design of an exemplary lens system, and it should be understood that the parametric design is for illustration only and does not limit the scope of the present invention.
TABLE 1 surface coefficients of lens systems
The aspherical surface curve equation of each lens is as follows:
wherein z is a position value in the optical axis direction at a position of height h with the surface vertex as a reference; c represents a curvature of the lens surface near the optical axis, and is an inverse of a curvature radius (R) (c 1/R); r is the curvature radius of the lens surface close to the optical axis; h is the perpendicular distance of the lens surface from the optical axis, k is the conic constant; and A is4、A6、A8、A10、A12、A14、A16… … are high order aspheric coefficients.
Table 2 below is an exemplary lens system aspheric coefficient design:
TABLE 2 aspherical coefficients
| Surface of | S3 | S4 | S5 | S6 | S7 | S8 |
| A4 | 0.3645 | -0.1458 | 0.6931 | -0.2576 | 0.0592 | -0.5301 |
| A6 | 13.6861 | 1.7982 | -15.2354 | 0.2675 | -1.5059 | 0.6205 |
| A8 | -209.9711 | -52.5978 | 71.9738 | -3.3906 | 4.5826 | -0.5493 |
| A10 | 930.7215 | 232.2076 | -145.9453 | 6.6285 | -5.4623 | 0.5236 |
| A12 | 263.5479 | -139.0152 | -210.5468 | 5.5024 | 1.8057 | -0.5027 |
| A14 | -1.2769E4 | -1468.4411 | 1448.3912 | -27.3476 | 0.9646 | 0.0564 |
| A16 | 2.5557E4 | 2836.2335 | -1633.8696 | 23.8596 | -0.5051 | 0.1289 |
In the parametric design example described above, the lens system is capable of operating at F/1.6 and is capable of achieving an angle of field of 81 deg. with an optical distortion of-24.1%. It is thus clear that under this exemplary parametric design, the embodiment of the utility model provides a lens system has better distortion compensation to big light ring imaging lens, can effectively solve the inhomogeneous problem of speckle density.
The above description is only exemplary of the present invention and should not be taken as limiting the scope of the present invention, as any modification, equivalent replacement or improvement made within the spirit and principle of the present invention should be included in the present invention.
In this specification, the schematic representations of the terms used above are not necessarily intended to refer to the same embodiment or example. Furthermore, the particular features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples. Furthermore, various embodiments or examples and features of different embodiments or examples described in this specification can be combined and combined by one skilled in the art without contradiction. Although embodiments of the present invention and their advantages have been described in detail, it should be understood that various changes, substitutions and alterations can be made herein without departing from the scope of the invention as defined by the appended claims.
Claims (10)
1. A lens system, characterized by: the lens comprises a first lens, a second lens and a third lens which are sequentially arranged along the incident direction of a light beam; wherein object side surfaces of the first and third lenses are convex at a paraxial region and image side surfaces of the first and third lenses are concave at a paraxial region; the object-side surface of the second lens element is concave at the paraxial region and the image-side surface is convex at the paraxial region; the first lens and the second lens have positive optical power, and the third lens has negative optical power.
2. The lens system of claim 1, wherein: the first lens, the second lens, and the third lens satisfy the following condition:
0<f1/f2<5；
-1<f2/f3<0；
-1<f12/f3<0；
0<f1/f23<3；
1.52<Nd<1.95；
0<f/TL<1；
wherein f is the effective focal length of the lens system; f. of1Is the effective focal length of the first lens; f. of2Is the effective focal length of the second lens; f. of3Is the effective focal length of the third lens; f. of12Is a combined focal length of the first lens and the second lens; f. of23Is the combined focal length of the second lens and the third lens; n is a radical ofdIs the refractive index of the lens material for D light; TL is the optical axisThe distance from the object side surface to the image side surface of the upper first lens.
3. The lens system of claim 1, wherein: the lens is characterized by further comprising an aperture diaphragm, wherein the aperture diaphragm is arranged between any two adjacent lenses; or, on the object side of the first lens.
4. The lens system of claim 1, wherein: the aperture value of a lens group formed by the first lens, the second lens and the third lens satisfies the following conditions: fno < 1.6.
5. The lens system of claim 1, wherein: the first lens, the second lens and the third lens are plastic lenses.
6. The lens system of claim 1, wherein: the third lens is a glass lens.
7. The utility model provides an imaging module which characterized in that: comprises an image sensor, a filter unit and a receiving optical element; wherein the receiving optical element is configured to receive at least a portion of the speckle pattern reflected back from the target object and direct the at least a portion of the speckle pattern onto the image sensor; the receiving optical element comprising a lens system according to any one of claims 1 to 6.
8. The imaging module of claim 7, wherein: the filtering unit is an infrared filter used for filtering background light or stray light.
9. A depth camera, characterized by: comprising the imaging module, the projection module, the processor and the substrate of claim 7; the projection module and the imaging module are arranged on the substrate at a preset baseline distance.
10. The depth camera of claim 9, wherein: the projection module comprises a light source consisting of one or more lasers for projecting an encoded speckle pattern into a target space; the imaging module collects photons in the speckle pattern reflected by the target object and outputs photon signals; the processor synchronizes the trigger signals of the projection module and the imaging module to calculate the flight time required by the photons from emission to reflection to reception, and the depth information of the target object is obtained.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202120788328.XU CN214427670U (en) | 2021-04-18 | 2021-04-18 | Lens system, imaging module and depth camera |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202120788328.XU CN214427670U (en) | 2021-04-18 | 2021-04-18 | Lens system, imaging module and depth camera |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN214427670U true CN214427670U (en) | 2021-10-19 |
Family
ID=78075329
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202120788328.XU Active CN214427670U (en) | 2021-04-18 | 2021-04-18 | Lens system, imaging module and depth camera |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN214427670U (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN114859529A (en) * | 2022-07-05 | 2022-08-05 | 江西联益光学有限公司 | Collimating lens |
-
2021
- 2021-04-18 CN CN202120788328.XU patent/CN214427670U/en active Active
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN114859529A (en) * | 2022-07-05 | 2022-08-05 | 江西联益光学有限公司 | Collimating lens |
| CN114859529B (en) * | 2022-07-05 | 2022-11-01 | 江西联益光学有限公司 | Collimating lens |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| US11314062B2 (en) | Collimating lens, projecting module and mobile phone | |
| CN109031591B (en) | Projection lens | |
| CN208907957U (en) | Projective module group, imaging modules and electronic device | |
| TW201942568A (en) | Diffractive optical assembly, laser projection module, depth camera and electronic device | |
| CN213987007U (en) | Light projector with telecentric lens | |
| CN214427670U (en) | Lens system, imaging module and depth camera | |
| TW201939095A (en) | Augmented reality device | |
| US20220365178A1 (en) | Optical detector | |
| CN111766754B (en) | Optical system and projection device | |
| JP2023518123A (en) | Objective lens, use of objective lens, measurement system including objective lens, and use of double-sided aspherical plastic lens in objective lens | |
| JP2017514179A (en) | Lens assembly for optical imaging | |
| CN214427610U (en) | Lens system, projection module and depth camera | |
| CN108303756B (en) | Laser projection module, depth camera and electronic device | |
| CN113296249B (en) | Infrared collimating lens and infrared lens module | |
| CN214623043U (en) | Lens system, imaging module and depth camera | |
| CN214122555U (en) | Lens system, projection module and depth camera | |
| US20120188613A1 (en) | Image Forming Optical Element, Image Forming Optical Array, And Image Reading Device | |
| CN215218570U (en) | Lens system, imaging module and TOF depth camera | |
| US9557526B2 (en) | Freeform imaging lens and freeform imaging system using the same | |
| CN208110175U (en) | Lens system, structured light projection mould group and depth camera | |
| CN215264246U (en) | Collimating lens system, projection module and depth camera | |
| CN215121040U (en) | High-performance lens system, imaging module and depth camera | |
| CN212341569U (en) | Lens system, structured light projection module and depth camera | |
| CN114839645A (en) | Time of flight TOF module and electronic equipment of making a video recording | |
| US20220397747A1 (en) | Objective, use of an objective and measurement system |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| GR01 | Patent grant | ||
| GR01 | Patent grant |