WO2011070656A1 - Distance measuring method and laser distance measuring apparatus - Google Patents

Distance measuring method and laser distance measuring apparatus Download PDF

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Publication number
WO2011070656A1
WO2011070656A1 PCT/JP2009/070585 JP2009070585W WO2011070656A1 WO 2011070656 A1 WO2011070656 A1 WO 2011070656A1 JP 2009070585 W JP2009070585 W JP 2009070585W WO 2011070656 A1 WO2011070656 A1 WO 2011070656A1
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WO
WIPO (PCT)
Prior art keywords
light
measurement
point
laser
position information
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PCT/JP2009/070585
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French (fr)
Japanese (ja)
Inventor
直行 古山
Original Assignee
Koyama Naoyuki
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Application filed by Koyama Naoyuki filed Critical Koyama Naoyuki
Priority to JP2011545015A priority Critical patent/JPWO2011070656A1/en
Priority to PCT/JP2009/070585 priority patent/WO2011070656A1/en
Publication of WO2011070656A1 publication Critical patent/WO2011070656A1/en

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    • 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
    • G01S17/00—Systems using the reflection or reradiation of electromagnetic waves other than radio waves, e.g. lidar systems
    • G01S17/02—Systems using the reflection of electromagnetic waves other than radio waves
    • G01S17/06—Systems determining position data of a target
    • G01S17/08—Systems determining position data of a target for measuring distance only
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01B—MEASURING LENGTH, THICKNESS OR SIMILAR LINEAR DIMENSIONS; MEASURING ANGLES; MEASURING AREAS; MEASURING IRREGULARITIES OF SURFACES OR CONTOURS
    • G01B11/00—Measuring arrangements characterised by the use of optical techniques
    • G01B11/02—Measuring arrangements characterised by the use of optical techniques for measuring length, width or thickness
    • G01B11/026—Measuring arrangements characterised by the use of optical techniques for measuring length, width or thickness by measuring distance between sensor and object
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01B—MEASURING LENGTH, THICKNESS OR SIMILAR LINEAR DIMENSIONS; MEASURING ANGLES; MEASURING AREAS; MEASURING IRREGULARITIES OF SURFACES OR CONTOURS
    • G01B9/00—Measuring instruments characterised by the use of optical techniques
    • G01B9/02—Interferometers
    • G01B9/02001—Interferometers characterised by controlling or generating intrinsic radiation properties
    • G01B9/02007—Two or more frequencies or sources used for interferometric measurement

Definitions

  • the present invention relates to a distance measuring method and a laser distance measuring apparatus for measuring a distance to a measurement object or a distance in a thickness direction between measurement points of the measurement object using interference of a laser beam.
  • the laser light is divided into reference light and measurement light, and the optical path difference between the reference light and measurement light reflected by the object to be measured is obtained. Measure the distance to the object to be measured.
  • the distance measurement accuracy is far from the wavelength level of the laser light, that is, the order of nm (nanometer).
  • Patent Document 1 the inventor of the present application uses a plurality of laser beams having different wavelengths, and further changes the optical path difference so as to utilize the coherence characteristic of the laser beams.
  • Inventions related to a laser distance measuring method and a laser distance measuring apparatus were made.
  • the distance to the object to be measured can be measured with high accuracy.
  • light / dark data intensity of interference light
  • Data light / dark data (intensity of interference light)
  • the present invention has been made in view of the above circumstances, and an object of the present invention is to provide a distance measuring method and a laser distance measuring apparatus capable of measuring a distance with a high accuracy in a relatively short time.
  • the present invention (1) Two or three laser beams that have different center frequencies and divide the reference beam and the measurement beam into the reference beam and the measurement beam, and all the reference beams can be moved in the direction of changing the optical path length. Based on the intensity data of the combined light in which all the measurement light is reflected at the measurement point S of the object 6 and the reference light reflected at the reflection point and the measurement light reflected at the measurement point are combined.
  • a distance measuring method for measuring a distance to a measurement point S of a device under test 6, comprising: The combined light has a maximum peak intensity at the position of the reflection point where the optical path length of the reference light and the optical path length of the measurement light are equal, and the specific condition is an intensity when the maximum peak intensity is 100%.
  • all of the reference light is reflected at the reflection point that can move in the direction of changing the optical path length, and all of the first measurement light is reflected at the first measurement point S1 of the object 6 to be measured.
  • the measurement light is reflected at the second measurement point S2 of the object 6 to be measured, each reference light reflected at the reflection point, each first measurement light reflected at the first measurement point, and each second measurement reflected at the second measurement point.
  • a distance measuring method for measuring a distance L in the thickness direction between the first measurement point S1 and the second measurement point S2 of the object to be measured 6 based on the intensity data of the combined light combined with the light In the combined light, the first position O (S1) of the reflection point where the optical path length of the reference light and the optical path length of the first measurement light are equal, or the optical path length of the reference light and the optical path length of the second measurement light are equal.
  • the maximum peak intensity is taken at the second position O (S2) of the reflection point, and the specific condition is that the first position O (S1) and the second position O (in the intensity data when the maximum peak intensity is 100%.
  • the peak intensity at positions other than S2) does not exceed a certain percentage of the maximum peak intensity
  • the first position O (S1) of the first position O (S1) of the reflection point where the intensity data of the combined light obtained by irradiating all the laser beams while moving the position of the reflection point has a peak intensity substantially equal to the maximum peak intensity.
  • a distance measuring method comprising: a measurement step of calculating a distance L in the thickness direction between the first measurement point S1 and the second measurement point S2 based on the first position information and the second position information.
  • the first measurement light is reflected at the first measurement point S1 of the object to be measured 6 and the second measurement light is reflected at the second measurement point S2 located on the back surface of the first measurement point S1
  • the measuring step calculates the thickness t of the object 6 based on the first position information, the second position information, and the origin position information.
  • the reflection unit 14 that reflects the reference light and can move in the direction in which the optical path length of the reference light changes
  • the position information acquisition unit 24 that acquires the position information of the reflection point of the reflection unit 14, and the reflection unit 14
  • the light receiving unit 18 that receives all reflected reference light and all measurement light reflected at the measurement point of the object 6 to be measured and outputs intensity data of the combined light, and obtains the position information based on the intensity data.
  • a calculation unit 20 that acquires position information from the unit 24 and performs a predetermined calculation.
  • the other peak intensities of the intensity data are maximum. Not exceed a certain percentage of peak intensity.
  • the reflection unit 14 that reflects the reference light and is movable in the direction in which the optical path length of the reference light changes, the position information acquisition unit 24 that acquires the position information of the reflection point of the reflection unit 14, and the measurement light
  • the measurement light dividing unit 28 that divides the first measurement light and the second measurement light, the first emission port 16a that emits the first measurement light, the second emission port 16b that emits the second measurement light, and the reflection unit 14 Receiving all of the reference light reflected by the first measurement light, all of the first measurement light reflected by the first measurement point S1 of the object 6 to be measured, and all of the second measurement light reflected by the second measurement point S2 of the object 6 to be measured.
  • the specific condition is that the optical path length of the reference light and the optical path length of the first measurement light in the intensity data are equal to the first position O (S1) of the reflection point or the optical path length of the reference light and the optical path of the second measurement light. Peaks at positions other than the first position O (S1) and the second position O (S2) in the intensity data when the maximum peak intensity at the second position O (S2) of the reflection point having the same length is 100%.
  • Laser ranging devices 50b and 51b are characterized in that the recording step and the measuring step described in (2) are performed to measure the distance L in the thickness direction between the first measurement point S1 and the second measurement point S2.
  • the reflection unit 14 that reflects the reference light and is movable in the direction in which the optical path length of the reference light changes, the position information acquisition unit 24 that acquires the position information of the reflection point of the reflection unit 14, and the measurement light
  • a measurement light dividing unit 28 that divides the first measurement light and the second measurement light, a first emission port 16a that emits the first measurement light, provided at a position facing the arrangement position of the DUT 6 and the first measurement light.
  • the specific condition is that the optical path length of the reference light and the optical path length of the first measurement light in the intensity data are equal to the first position O (S1) of the reflection point or the optical path length of the reference light and the optical path of the second measurement light.
  • the intensity does not exceed a certain percentage of the maximum peak intensity
  • the distance to the object to be measured or the distance in the thickness direction between two measurement points of the object to be measured can be measured with high accuracy in a relatively short time. it can.
  • FIG. 1 shows a laser range finder 50a according to a first embodiment of the present invention.
  • the broken lines in FIGS. 1 and 3 to 7 indicate the optical path of the laser beam.
  • a laser distance measuring device 50a according to the present invention shown in FIG. 1 emits two laser beams (first laser beam and second laser beam) having different center frequencies and satisfying specific conditions described later. It has laser irradiation means 10a and second laser irradiation means 10b.
  • the types of the first laser irradiation unit 10a, the second laser irradiation unit 10b, and the third laser irradiation unit 10c to be described later are not particularly limited as long as specific conditions described later are satisfied, and helium neon laser, argon laser, krypton ion laser.
  • a gas laser such as a helium cadmium laser, a solid laser such as a ruby laser or a YAG laser, a metal laser, a semiconductor laser, or the like can be used.
  • a laser irradiation means of multi-longitudinal mode oscillation having a relatively broad frequency distribution.
  • the laser beam of multi-longitudinal mode oscillation means that the frequency distribution of the oscillating laser beam is broad, and this includes the one whose frequency distribution is broadened as a result of performance, stability, variation, etc. To do. Therefore, the laser distance measuring device 50a and the laser distance measuring devices 50b, 50c, 51a, 51b, 51c described later do not necessarily require expensive laser irradiation means having high frequency stability and a stable emission spectrum. An inexpensive laser irradiation means with relatively inferior emission spectrum stability can be used. Therefore, it is particularly preferable to use an inexpensive semiconductor laser as the laser irradiation means to be used.
  • the semiconductor laser By using the semiconductor laser, it is possible to reduce the component costs of the laser distance measuring devices 50a to 51c, and to provide the laser distance measuring devices 50a to 51c at a lower cost. If at least one of the laser irradiation means to be used has an oscillation wavelength in the visible light region of 400 nm to 750 nm, the irradiation position of the laser light can be seen and the workability can be improved. it can.
  • the first laser light emitted from the first laser irradiation means 10a is reflected by the mirror 4a provided on the optical path of the first laser light and travels toward the dividing section 12.
  • the second laser light emitted from the second laser irradiation means 10b is reflected by the half mirror 4b provided on the optical path of the second laser light, passes through the same optical path as the first laser light, and travels to the dividing unit 12.
  • a half mirror, a beam splitter, or the like is used as the dividing unit 12, and the first laser beam and the second laser beam that have reached the dividing unit 12 are divided into two at the dividing point of the dividing unit 12. One is directed to the reflecting portion 14 as reference light, and the other is directed to the measured object 6 side as measurement light.
  • the reference light of the first laser beam and the second laser beam divided by the dividing unit 12 is reflected at the reflection point of the reflecting unit 14, passes through the dividing unit 12, and reaches the light receiving unit 18.
  • the moving unit 22 is installed in the reflecting unit 14, and the reflecting unit 14 moves in a direction in which the distance from the reflecting point to the dividing point, that is, the optical path length of the reference light is changed by the operation of the moving unit 22.
  • the position information acquisition unit 24 operates a moving unit 22 in response to a signal from a device control unit (not shown), and outputs position information of a reflection point that is changed by the operation of the moving unit 22 to the calculation unit 20.
  • the moving means 22 it is preferable to use a sliding ultrasonic motor or the like that moves about 5 to 10 nm in one step.
  • the position information of the reflection point is indirectly substituted with the position information of the reflection part 14. Is also possible.
  • the measurement light of the first laser beam and the second laser beam divided by the dividing unit 12 is emitted from the emission port 16. Then, as shown in FIG. 1B, the measurement light of the first laser light and the second laser light emitted from the emission port 16 is reflected at the measurement point S of the object 6 to be received via the dividing unit 12. Part 18 is reached.
  • the light receiving unit 18 receives the measurement light of the first laser light and the second laser light reflected at the measurement point S and the reference light of the first laser light and the second laser light reflected at the reflection point, and receives these lights.
  • the combined intensity data of the combined light is converted into an electrical signal and output to the arithmetic unit 20.
  • the position information acquisition unit 24 operates the moving unit 22 to move the position of the reflection point in the direction in which the optical path length of the reference light changes.
  • the optical path length of the reference light changes
  • the optical path difference between the reference light and the measurement light changes, and the intensity data of the combined light output from the light receiving unit 18 changes accordingly.
  • the calculation unit 20 acquires the position information of the reflection point at that time from the position information acquisition unit 24 and performs the calculation described later.
  • the reference light and the measurement light are intensified and interfered with any laser light having any oscillation wavelength.
  • the light has a bright peak.
  • the interference light does not exist in that there is no optical path difference between the reference beam and the measurement beam. Always keep the bright peaks.
  • FIG. 2A schematically showing the relationship between the position of the reflection point and the intensity of the interference light
  • the measurement light of the first laser light interferes with the reference light of the first laser light.
  • the generated interference light ((A) in FIG. 2A) interferes with the measurement light of the second laser light and the reference light of the second laser light ((B in FIG. 2A). )) Both take a bright peak at a reflection point position O where the optical path length of the reference light and the optical path length of the measurement light are equal, and the combined light ((C) in FIG.
  • the intensity takes the maximum peak intensity. Further, there is no point other than the position O where the peak positions of the interference light (A) by the first laser light and the interference light (B) by the second laser light completely coincide. Therefore, in these synthesized lights, there is no position having a peak intensity equal to or greater than the maximum peak intensity other than the position O.
  • the peak of the interference light (A) due to the first laser light and the peak of the interference light (B) due to the second laser light are close (for example, A position O ′) in FIG. 2 exists.
  • the peak intensity of the combined light may approach the maximum peak intensity.
  • the calculation unit 20 may erroneously recognize the position O ′ as the position O.
  • the first laser irradiation unit 10a and the second laser irradiation unit 10b are combined when the maximum peak intensity at the position O of the reflection point where the optical path length of the reference light and the optical path length of the measurement light are equal is 100%.
  • a combination must be selected such that the peak intensities other than position O in the light intensity data do not exceed a certain percentage of the maximum peak intensity.
  • This specific percentage value is a value sufficient for the calculation unit 20 to distinguish between the maximum peak intensity and the other peak intensities.
  • the range is about 80% to 98%.
  • the value is preferably 97%, and in the case of using three laser beams described later, the value is in the range of about 60% to 97%, preferably 90%.
  • the peak can be easily determined by the calculation unit 20, but the degree of freedom in selecting the laser irradiation means is reduced. Further, if it approaches 100%, the selection range of the laser irradiation means is widened, but it is difficult to determine the peak by the calculation unit 20. Note that the position O ′ in FIG. 2 is an example, and the position O ′ does not necessarily come next to the position O.
  • the frequency distribution and stability of the laser light emitted by the laser irradiation means vary depending on the oscillation characteristics, operation output, device configuration, individual variations, and the like. This tendency is particularly noticeable for inexpensive semiconductor lasers. Whether or not the above specific condition is satisfied depends not only on the center frequency of the laser beam but also on the frequency distribution. Therefore, the selection of the first laser irradiation means 10a and the second laser irradiation means 10b is performed by actually mounting the selected first laser irradiation means 10a and second laser irradiation means 10b on the laser distance measuring device 50a. It is preferable to carry out after confirming.
  • the first laser irradiation means 10a and the second laser irradiation means 10b to be selected are mounted on the laser distance measuring device 50a.
  • the exit port 16 is closed with a shutter 5 having a smooth surface.
  • the moving means 22 is operated to simultaneously irradiate the first laser beam and the second laser beam while moving the reflecting portion 14 within a predetermined range.
  • the light receiving unit 18 receives each reference light reflected by the reflection point and each measurement light reflected by the reflection point S ′ of the shutter 5, and outputs intensity data of these combined lights.
  • the distance from the division point to the reflection point is a distance Lr (s ′)
  • the distance from the division point to the reflection point S ′ of the shutter 5 is a distance Lm (s ′)
  • the position of the reflection point equal to Lm (s ′) is the position O (s ′) and the coherence length of the first laser beam or the second laser beam is Lc
  • the movement range of the reflection unit 14 is the position O.
  • a range of O (s ′) ⁇ (Lc / 2) centered on (s ′) is preferable.
  • the position O (s') cannot be specified with high accuracy, but no particular problem occurs when the laser irradiation means is selected.
  • the intensity data obtained as described above takes the maximum peak intensity at the position O (s') where the distance Lr (s') and the distance Lm (s') match.
  • the intensity data takes an intensity peak corresponding to the peak of the interference light by the first laser light and the peak of the interference light by the second laser light. Then, the peak intensity of these intensity data is confirmed, and the value of the maximum peak intensity (position O (s ′)) is obtained. Note that there is a possibility that the value of the maximum peak intensity will fluctuate due to output fluctuations of the first laser irradiation means 10a and the second laser irradiation means 10b. In such a case, an average value of peak intensities at this position (position O (s ′)) may be set as the maximum peak intensity.
  • the maximum peak intensity is 100%, if all other peak intensities are less than 95% of the maximum peak intensity even if the output fluctuation of the laser irradiation means is taken into account, the first laser irradiation means 10a. And the second laser irradiation means 10b are determined to be adoptable. Then, the calculation unit 20 records a value of 95% of the maximum peak intensity at this time as a determination criterion in a memory or the like (not shown). On the other hand, when there are other peak intensities that exceed 95% of the maximum peak intensity including the output fluctuation of the laser irradiation means, a new combination of the first laser irradiation means 10a and the second laser irradiation means 10b is selected. To do.
  • the peak of the interference light becomes broader as the distance from the position O increases, and the peak intensity decreases accordingly. Therefore, if the distance from the position O is more than a certain distance, even if the peak positions of the interference light by the first laser light and the interference light by the second laser light are very close, the peak intensity is less than 95% of the maximum peak intensity.
  • the above moving range can be further reduced to about (Lc / 4) around the position O (s ′).
  • the selection of the laser irradiation means described above is basically the same in the laser distance measuring devices 50b and 50c described later. However, in the laser distance measuring devices 50b and 50c, the above laser irradiation means is selected by shielding one of the first measurement light and the second measurement light.
  • a third laser irradiation means 10c having a different center frequency from the first laser light and the second laser light may be provided.
  • the third laser irradiation means 10c interference light due to the third laser light is generated, and the interference light due to the third laser light is located at the position O similarly to the interference light due to the first laser light and the interference light due to the second laser light. Take the peak of the bright part.
  • the probability that the interference light beams by the third laser light, the interference light by the first laser light, and the interference light by the second laser light are all close except at the position O is significantly lower than when two laser lights are used. . Therefore, by providing the third laser irradiation means 10c, the degree of freedom in selecting the laser irradiation means can be expanded. Further, by providing the third laser irradiation means 10c, the difference between the maximum peak intensity value and the other peak intensity values is increased compared with the case where two laser beams are used. Identification can be performed more easily.
  • the selection of the third laser irradiation means 10c is such that the peaks of the two bright parts of the interference light ((D) in FIG. 2B) by the third laser light are It is preferable to select so as to sandwich the position of the peak intensity exceeding 95% of the maximum peak intensity at the time of two lasers (for example, the position O ′ in FIG. 2A).
  • the selection of the three laser irradiation means is to set the center frequency of the first laser light as ⁇ a, the center frequency of the second laser light as ⁇ b, and the center frequency of the third laser light as ⁇ c, As a guideline, 3 ⁇ ⁇ a ⁇ c may be satisfied when ⁇ a ⁇ b ⁇ c.
  • the basic operation of the laser distance measuring device 51a having three laser irradiation means is exactly the same.
  • the reference point position information acquisition method here is basically the same as the first distance measurement method and the operation of the laser distance measuring device 50a.
  • the exit port 16 is closed with the shutter 5.
  • the reflection point of the reflection unit 14 is positioned at the starting position.
  • the starting point position is preferably a reflection point position equal to the distance from the dividing point to the exit port 16.
  • the first laser irradiation unit 10a and the second laser irradiation unit 10b are operated to irradiate the first laser beam and the second laser beam simultaneously.
  • the light receiving unit 18 receives the reference light of each laser beam reflected at the reflection point and the measurement light of each laser beam reflected at the reflection point S ′ of the shutter 5, and intensity data of these combined lights Is output to the arithmetic unit 20.
  • the position information acquisition unit 24 operates the moving unit 22 to move the reflection point together with the reflection unit 14 in the direction in which the optical path length of the reference light increases.
  • the optical path length of the measurement light 2 ⁇ Lm (s ′) and the optical path of the reference light The length 2 ⁇ Lr (s ′) is equal. Therefore, the intensity of the synthesized light takes the maximum peak intensity at this position O (s ′).
  • the calculation unit 20 monitors at any time whether or not the intensity of the combined light from the light receiving unit 18 exceeds a criterion (95% of the maximum peak intensity) in consideration of output fluctuation of the laser irradiation means.
  • a criterion 95% of the maximum peak intensity
  • the calculation unit 20 has the position of the reflection point that takes the maximum intensity within a range that satisfies the determination criterion. That is, the position information of the reflection point having the maximum peak intensity is acquired from the position information acquisition unit 24 and recorded as the position information of the reference point. Note that the position of this reference point corresponds to the position O (s ′) in FIG.
  • the distance to the measurement point S of the DUT 6 is measured.
  • the measurement object 6 is installed while removing the shutter 5, and the measurement light of the first laser light and the second laser light is reflected at the measurement point S of the measurement object 6.
  • the light receiving unit 18 receives the reference light of each laser beam reflected at the reflection point and the measurement light of each laser beam reflected at the measurement point S of the object 6 to be measured, and the intensity of the combined light.
  • Data is output to the arithmetic unit 20.
  • the position information acquisition unit 24 operates the moving unit 22 to further move the reflection point in the direction in which the optical path length of the reference light increases.
  • the reflection point moves and the distance Lr (s) becomes the distance.
  • the optical path length 2 ⁇ Lm (s) of the measurement light is equal to the optical path length 2 ⁇ Lr (s) of the reference light. Therefore, the intensity of the synthesized light takes the maximum peak intensity at this position O (s).
  • the arithmetic unit 20 monitors whether or not the intensity of the combined light from the light receiving unit 18 exceeds the criterion, and satisfies the criterion when the position of the reflection point approaches the position O (s) and exceeds the criterion.
  • the position of the reflection point having the maximum intensity within the range that is, the position information of the reflection point having the maximum peak intensity is acquired from the position information acquisition unit 24 and recorded. This recorded position information corresponds to the position information of the position O (s). The above corresponds to the recording step.
  • the calculation unit 20 uses the position information of the reference point (position information of the position O (s ′)) and the position information of the position O (s) obtained in the recording step to determine the emission port 16 that is the reference point.
  • a distance L from the emission point (corresponding to the reflection point S ′ of the shutter 5) to the measurement point S of the DUT 6 is calculated.
  • the calculation method of the distance L is, for example, when the position information value of the reference point is POs ′, the position information of the position O (s) is POs, and the position information value increases as the reflecting unit 14 moves away from the dividing unit 12.
  • the moving means 22 is a mechanical device such as a motor, it may be difficult to completely position the reflection point at each position, particularly at the peak position, depending on the accuracy of the moving means 22.
  • the intensity data in a range exceeding the determination criterion may be plotted, and the position of the reflection point having the maximum intensity may be calculated by calculation. The same applies to a second distance measuring method and a third distance measuring method described later.
  • the reference point is not the inner surface of the shutter 5, but is set as the first measurement point S1 of the object 6 to be measured, and after the position information of the first measurement point S1 is acquired, FIG.
  • the laser distance measuring device 50a or the object to be measured 6 is translated to reflect the measurement light at the second measurement point S2 of the object to be measured 6, the obtained distance L is the first measurement point. This is the distance in the thickness direction between S1 and the second measurement point S2.
  • the positional relationship between the first measurement point S1 and the second measurement point S2 is grasped in advance, and the side closer to the laser distance measuring device 50a (the first measurement point S1 in the example of FIG. 4) is used as a reference point.
  • the far side (second measurement point S2 in the example of FIG. 4) be the measurement point.
  • the direction of movement of the moving means 22 is the direction in which the optical path length of the reference light decreases
  • the side far from the laser distance measuring device 50a (second measurement point S2 in the example of FIG. 4) is used as a reference point. It is preferable to use the near side (the first measurement point S1 in the example of FIG. 4) as the measurement point.
  • a laser distance measuring device 50b according to the present invention shown in FIG. 5 includes a measurement light dividing unit 28 for dividing the measurement light into a first measurement light and a second measurement light in addition to the laser distance measurement device 50a of the first embodiment. have. Then, the first measurement light of the first laser light and the second laser light divided by the measurement light dividing unit 28 is emitted from the first emission port 16a to the measured object 6 side. Further, the second measurement light of the first laser light and the second laser light divided by the measurement light dividing unit 28 is reflected by the mirror 8 and emitted from the second emission port 16b to the object to be measured 6 side.
  • the optical path difference (2 ⁇ Ld) in the apparatus between the first measurement light and the second measurement light is longer than the longer coherence length of the first laser light and the second laser light. Therefore, the distance Ld is a distance longer than 1 ⁇ 2 of the longer coherence length of the first laser beam and the second laser beam.
  • the laser irradiation means is selected in a state where one of the first measurement light and the second measurement light is shielded. Further, the maximum peak intensity in the second distance measuring method and the third distance measuring method is set so that one measurement light does not interfere. That is, the maximum peak intensity in the second distance measurement method and the third distance measurement method is the interference light (at the position O in FIG. 2) of the first laser beam by the first measurement light (second measurement light). The intensity peak, the intensity peak of interference light (at position O in FIG. 2) due to the first measurement light (second measurement light) of the second laser light, and the optical path difference exceeds the coherence length and is constant intensity as will be described later. And the intensity of the second measurement light (first measurement light) of the first laser light and the second laser light. Then, a criterion value is set according to the maximum peak intensity and the output fluctuation range of the laser irradiation means.
  • the second distance measuring method according to the present invention will be described together with the operation of the laser distance measuring device 50b.
  • the basic operation of the laser distance measuring device 51b shown in FIG. 7A having three laser irradiation means is exactly the same.
  • the laser distance measuring device 50b it is necessary to obtain a distance Ld that is a value of 1 ⁇ 2 of the optical path difference between the first measurement light and the second measurement light in the device in advance.
  • a method for obtaining the distance Ld suitable for the laser distance measuring device 50b will be described later.
  • the distance Ld need not be obtained every measurement, and may be recorded at the time of shipment of the laser distance measuring device 50b and recorded in a memory or the like.
  • the first measuring light is measured at the first measuring point S1 of the device under test 6 and the second measured at the second measuring point S2. Install so that the measurement light is irradiated vertically.
  • the reflection point of the reflection unit 14 is positioned at the starting position.
  • the starting position here is preferably a position of a reflection point equal to the distance from the dividing point to the first exit port 16a.
  • the first laser irradiation unit 10a and the second laser irradiation unit 10b are operated to irradiate the first laser beam and the second laser beam simultaneously.
  • the reference light of the first laser light and the second laser light is reflected at the reflection point and reaches the light receiving unit 18.
  • the first measurement light of the first laser light and the second laser light divided by the measurement light dividing unit 28 is emitted from the first emission port 16a, and then reflected by the first measurement point S1 of the object 6 to be measured.
  • the light reaches the light receiving unit 18 via the measurement light dividing unit 28 and the dividing point.
  • the second measurement light of the first laser light and the second laser light is emitted from the second emission port 16b and then reflected by the second measurement point S2 of the object 6 to be measured, and the mirror 8, the measurement light dividing unit 28, It reaches the light receiving unit 18 via the dividing point.
  • the light-receiving unit 18 includes a reference beam for the first laser beam and the second laser beam, a first measurement beam for the first laser beam and the second laser beam, and a second measurement beam for the first laser beam and the second laser beam. , And outputs the intensity data of the combined light in which all the lights are combined to the arithmetic unit 20. Then, while maintaining this state, the position information acquisition unit 24 operates the moving unit 22 to move the reflection point in the direction in which the optical path length of the reference light increases together with the reflection unit 14.
  • the optical path length of the first measurement light and the optical path length of the reference light And become equal. Further, since the distance Ld is longer than the coherence length of the first laser light and the second laser light, the optical path difference between the second measurement light and the reference light exceeds the coherence length near the position O (s1), and the second measurement is performed. The light does not interfere with the reference light and the first measurement light. Therefore, the second measurement light is received by the light receiving unit 18 as light having a constant intensity, and the second measurement light does not adversely affect the acquisition of the first position information. Since the maximum peak intensity in the second distance measuring method is such that one of the measurement lights does not interfere, the intensity of the synthesized light at this position O (s1) is substantially equal to the maximum peak intensity. .
  • the calculation unit 20 monitors whether or not the intensity of the combined light from the light receiving unit 18 exceeds the determination criterion, and when it exceeds the determination criterion, the first reflection point having the maximum intensity within the range satisfying the determination criterion.
  • the reflection point further moves and the distance from the division point to the reflection point reaches a position O (s2) equal to the distance from the division point ⁇ the measurement light dividing unit 28 ⁇ the mirror 8 ⁇ the second measurement point S2,
  • the optical path length of the second measurement light is equal to the optical path length of the reference light.
  • the intensity of the synthesized light is similarly substantially equal to the maximum peak intensity.
  • the calculation unit 20 monitors whether or not the intensity of the combined light from the light receiving unit 18 exceeds the determination criterion, and when it exceeds the determination criterion, the second reflection point having the maximum intensity within the range satisfying the determination criterion.
  • the above corresponds to the recording step of the second distance measuring method. Since the distance Ld is longer than the coherence length of the first laser light and the second laser light as described above, the optical path difference between the first measurement light and the reference light exceeds the coherence length in the vicinity of the position O (s2).
  • the first measurement light does not interfere with the reference light and the second measurement light. Therefore, the first measurement light does not adversely affect the acquisition of the second position information.
  • the calculation unit 20 determines between the first measurement point S1 and the second measurement point S2 of the DUT 6 from the first position information, the second position information, and the value of the distance Ld acquired in advance.
  • a distance L in the thickness direction is calculated.
  • the calculation method of the distance L is, for example, when the value of the first position information is Ps1, the second position information is Ps2, and the value of the position information increases as the reflecting unit 14 moves away from the dividing unit 12.
  • L Ps2-Ps1-Ld It becomes. The above corresponds to the measurement step of the second distance measuring method.
  • the distance Ld acquisition method described below is basically the same as the operation of the second distance measuring method and the laser distance measuring device 50b according to the present invention. Further, the method for obtaining the distance Ld shown below is suitable for the laser distance measuring device 50b according to the present invention, but this method is not necessarily used.
  • the flat plate 5 having a smooth surface is irradiated with the first measurement light perpendicularly to the first measurement point S1 ′ and the second measurement light perpendicularly to the second measurement point S2 ′.
  • the reflection point of the reflection unit 14 is positioned at a position where the optical path length of the reference light is slightly shorter than the starting position.
  • the above recording step is performed, and the first position O (s1 ′) of the reflection point at which the distance from the division point to the first measurement point S1 ′ of the flat plate 5 is equal to the distance from the division point to the reflection point.
  • the second position information is recorded.
  • the computing unit 20 calculates the distance Ld from the obtained first position information and second position information.
  • the calculation method of the distance Ld is, for example, when the value of the first position information is Ps1 ′, the second position information is Ps2 ′, and the value of the position information increases as the reflecting unit 14 moves away from the dividing unit 12.
  • Ld Ps2′ ⁇ Ps1 ′ It becomes.
  • FIG. 6 shows a laser distance measuring device 50c according to a third embodiment of the present invention.
  • the laser range finder 50c according to the third embodiment has a thickness direction between a first measurement point S1 located on one surface side of the object 6 to be measured and a second measurement point S2 located on the back surface of the first measurement point S1. By measuring the distance, the thickness t of the DUT 6 is measured. Therefore, the configuration is basically the same as that of the laser distance measuring device 50b of the second embodiment except that the optical paths of the first measurement light and the second measurement light are different.
  • the first measurement light divided by the measurement light dividing unit 28 is reflected by the mirror 8a, the mirror 8b, and the mirror 8c and is directed from the first emission port 16a to the second emission port 16b. And exit.
  • the second measurement light split by the measurement light splitting unit 28 is reflected by the mirror 8d and the mirror 8e, and exits from the second exit 16b toward the first exit 16a.
  • the 1st output port 16a and the 2nd output port 16b are provided in the position which opposes, and the to-be-measured object 6 is arrange
  • the first emitted from the first emission port 16a in the case of an unmeasured object state in which nothing exists between the first emission port 16a and the second emission port 16b, the first emitted from the first emission port 16a.
  • the measurement light again enters the laser distance measuring device 50c from the second exit 16b, is reflected by the mirror 8e and the mirror 8d, and returns to the measurement light splitting unit 28.
  • the second measurement light emitted from the second emission port 16b is incident on the laser distance measuring device 50c again from the first emission port 16a, reflected by the mirror 8c, the mirror 8b, and the mirror 8a, and returned to the measurement light dividing unit 28. To do.
  • the first measurement light and the second measurement light travel on the same optical path in opposite directions and return to the measurement light splitting unit 28. Accordingly, the optical path lengths of the first measurement light and the second measurement light at this time are equal. It should be noted that the optical path length of the first measurement light from the measurement light dividing unit 28 to the first emission port 16a and the optical path length of the second measurement light from the measurement light division unit 28 to the second emission port 16b need to be completely equal.
  • the optical path of the first measurement light and the second measurement light in the unmeasured object state from the measurement light splitting unit 28 to the measurement light splitting unit 28 (ie, the measurement light splitting in the first measurement light)
  • the intermediate point P0 between the first exit port 16a and the second exit port 16b is an intermediate point P0 of the section 28 ⁇ mirror 8a ⁇ mirror 8b ⁇ mirror 8c ⁇ mirror 8e ⁇ mirror 8d ⁇ light path to the measurement light splitting section 28) It is preferable to be in the vicinity.
  • the position of the reflection point (origin position O) where the optical path lengths of the first measurement light and the second measurement light are equal to the optical path length of the reference light is obtained to obtain the origin.
  • An origin acquisition step of recording as position information is performed.
  • the origin position information is preferably acquired as follows.
  • the reflecting point of the reflecting portion 14 is positioned at the starting position in the state of no measurement object.
  • the starting position here is preferably a position of a reflection point that is slightly longer than the optical path of the measuring light from the dividing point to the intermediate point P0.
  • the first laser irradiation unit 10a and the second laser irradiation unit 10b are operated to simultaneously irradiate the first laser beam and the second laser beam.
  • the reference light reaches the light receiving unit 18 along the optical path of the dividing point ⁇ the reflection point ⁇ the dividing point ⁇ the light receiving unit 18.
  • the first measurement light is divided at the division point ⁇ measurement light division unit 28 ⁇ mirror 8a ⁇ mirror 8b ⁇ mirror 8c ⁇ first emission port 16a ⁇ second emission port 16b ⁇ mirror 8e ⁇ mirror 8d ⁇ measurement beam division unit 28 ⁇ division.
  • the light path from the point to the light receiving unit 18 is reached and reaches the light receiving unit 18.
  • the second measurement light is divided at the division point ⁇ measurement light division unit 28 ⁇ mirror 8d ⁇ mirror 8e ⁇ second emission port 16b ⁇ first emission port 16a ⁇ mirror 8c ⁇ mirror 8b ⁇ mirror 8a ⁇ measurement light division unit 28 ⁇ division.
  • the light path from the point to the light receiving unit 18 is reached and reaches the light receiving unit 18.
  • the position information acquisition unit 24 operates the moving unit 22 to move the reflection point in the direction in which the optical path length of the reference light decreases together with the reflection unit 14.
  • the reference light of the first laser light and the first light are transmitted at the origin position O.
  • the interference light caused by the first measurement light and the second measurement light of the laser light and the interference light caused by the reference light of the second laser light and the first measurement light and the second measurement light of the second laser light are all in the bright part. Take a peak.
  • the maximum peak intensity in the third distance measuring method is that in which one of the measurement lights does not interfere, the intensity of the combined light at the origin position O is about twice the maximum peak intensity. Take. Therefore, the criterion for obtaining the origin position information is increased accordingly.
  • the computing unit 20 monitors whether or not the intensity of the combined light from the light receiving unit 18 exceeds a determination criterion at the time of acquiring the origin position information.
  • the origin position O on the optical path of the reference light corresponds to the intermediate point P0 on the optical path of the measurement light in FIG.
  • the origin position information acquisition method described above has the highest accuracy and is suitable for the laser distance measuring device 50c according to the present invention, but it is not always necessary to use this method.
  • the acquisition of the origin position information is preferably performed for each measurement. However, this is not the case when a highly accurate measurement value is not required.
  • the DUT 6 is disposed between the first exit port 16a and the second exit port 16b.
  • the measured object 6 overlaps the intermediate point P0, and the difference between the distance L1 from the intermediate point P0 to the first measurement point S1 and the distance L2 from the intermediate point P0 to the second measurement point S2 is the first laser beam. It is preferable that the distance is longer than the half of the longer coherence length of the second laser beam.
  • either the optical path length of the first measurement light or the optical path length of the second measurement light at the time of measurement is the optical path length of the reference light at the origin position. Longer and the other shorter.
  • the machine such as a motor that is the moving means 22 is operated in a certain direction, there is no great difference between the position information and the actual position. An error occurs.
  • the DUT 6 is arranged so as to overlap the intermediate point P0, the optical path length of the first measurement light and the optical path length of the second measurement light at the time of measurement are both shorter than the optical path length of the reference light at the origin position,
  • the reflection unit 14 only needs to move from the origin position in the direction of decreasing the optical path length of the reference light, and the moving unit 22 does not need to operate in reverse. Therefore, highly accurate thickness measurement can be performed.
  • the second measurement light interferes when measuring the first measurement point S1 by the first measurement light described later.
  • the first measurement light does not interfere when measuring the second measurement point S2 by the second measurement light. Accordingly, the distance measurement of the thickness t of the DUT 6 by the laser distance measuring device 50c can be efficiently performed. If the thickness t of the device under test 6 is smaller than 1 ⁇ 2 of the coherence length and the above condition cannot be satisfied, the device under test 6 is shifted from the intermediate point P0, and the first measurement light and the second measurement light Is equal to or greater than the coherence length.
  • the moving means 22 requires reverse operation and an error due to backlash occurs.
  • the repeat position accuracy including backlash is about 20 nm, and the required measurement is performed. Depending on the accuracy, it can be used sufficiently.
  • the laser distance measuring device 50c sets the optical path of the measurement light as shown in FIG. 8, and the optical path difference between the first measurement light and the second measurement light inside the device is either the first laser light or the second laser light.
  • the distance may be longer than the longer coherence length. According to this configuration, since the optical path difference between the first measurement light and the second measurement light inside the apparatus is already set longer than the coherence length, the measurement object 6 can be measured regardless of the installation position of the measurement object 6. Distance measurement of the thickness t can be performed. However, in this case, the reverse operation of the moving means 22 is required.
  • the first laser irradiation unit 10a and the second laser irradiation unit 10b are operated to irradiate the first laser beam and the second laser beam simultaneously.
  • the reference light of the first laser light and the second laser light is reflected at the reflection point and reaches the light receiving unit 18.
  • the first measurement light of the first laser light and the second laser light divided by the measurement light dividing unit 28 is emitted from the first emission port 16a, and then reflected by the first measurement point S1 of the object 6 to be measured.
  • the light reaches the light receiving unit 18 via the mirror 8c, the mirror 8b, the mirror 8a, the measuring light dividing unit 28, and the dividing point.
  • the second measurement light of the first laser light and the second laser light is emitted from the second emission port 16b and then reflected at the second measurement point S2 of the object 6 to be measured, and the mirror 8e, the mirror 8d, and the measurement light division.
  • the light reaches the light receiving part 18 via the part 28 and the dividing point.
  • the light-receiving unit 18 includes a reference beam for the first laser beam and the second laser beam, a first measurement beam for the first laser beam and the second laser beam, and a second measurement beam for the first laser beam and the second laser beam. And outputs the intensity of the combined light, which is a combination of all the lights, to the arithmetic unit 20.
  • the position information acquisition unit 24 operates the moving unit 22 to move the reflection point in the direction in which the optical path length of the reference light decreases together with the reflection unit 14.
  • the reflection point moves and reaches the position O (s1) where the distance from the division point to the reflection point is equal to the optical path length of one way of the first measurement light from the division point to the first measurement point S1, the first measurement light is reached. Is equal to the optical path length of the reference light.
  • the interference light from the first laser light of the first measurement light and the interference light from the second laser light of the first measurement light have a bright peak, and at this position O (s1).
  • the intensity of the synthesized light is substantially equal to the maximum peak intensity.
  • the calculation unit 20 monitors whether or not the intensity of the combined light from the light receiving unit 18 exceeds the determination criterion, and when it exceeds the determination criterion, the first reflection point having the maximum intensity within the range satisfying the determination criterion.
  • the distance from the origin position O to the position O (s1) corresponds to the distance L1.
  • the optical path difference between the first measurement light and the second measurement light is longer than the coherence length of the first laser light and the second laser light. Therefore, the second measurement light does not interfere in the vicinity of the position O (s1), and the second measurement light does not adversely affect the acquisition of the first position information.
  • the reflection point when the reflection point further moves and reaches a position O (s2) where the distance from the division point to the reflection point is equal to the optical path length of one way of the second measurement light from the division point to the second measurement point S2,
  • the optical path length of the second measurement light is equal to the optical path length of the reference light.
  • the interference light by the first laser light of the second measurement light and the interference light by the second laser light of the second measurement light have a bright peak, and the combined light at this position O (s2).
  • the intensity of is substantially equal to the maximum peak intensity.
  • the calculation unit 20 monitors whether or not the intensity of the combined light from the light receiving unit 18 exceeds the determination criterion, and when it exceeds the determination criterion, the second reflection point having the maximum intensity within the range satisfying the determination criterion.
  • the optical path difference between the first measurement light and the second measurement light is longer than the coherence length of the first laser light and the second laser light. Therefore, in the vicinity of the position O (s2), the first measurement light does not interfere and the first measurement light does not adversely affect the acquisition of the second position information.
  • the above corresponds to the recording step of the third distance measuring method.
  • the calculation unit 20 calculates the distance in the thickness direction between the first measurement point S1 and the second measurement point S2 of the object 6 to be measured, based on the first position information, the second position information, and the origin position information.
  • the thickness t of the DUT 6 is calculated.
  • the calculation method of the thickness t is, for example, when the origin position information is Po, the first position information value is Ps1, and the second position information is Ps2, and the position information value increases as the reflecting portion 14 moves away from the dividing portion 12.
  • the above corresponds to the measurement step of the third distance measuring method.
  • the distance measuring method and laser distance measuring device monitor the intensity of the combined light as needed, and acquire the position information of the reflection point whose peak intensity is substantially equal to the maximum peak intensity, Based on the position information, the distance to the object to be measured or the distance in the thickness direction between two measurement points of the object to be measured is measured. Therefore, it is not necessary to acquire a wide range of intensity data, and highly accurate distance measurement can be performed in a relatively short time while utilizing the coherence of the laser beam.
  • the optical paths of the reference light, measurement light, first measurement light, and second measurement light are partially optical.
  • the configuration of each part, each optical path, and the like can be changed and implemented without departing from the scope of the present invention.

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Abstract

Provided are a distance measuring method and a laser distance measuring apparatus by which a distance can be measured in a relatively short time with high accuracy. In the distance measuring method and the laser distance measuring apparatus, the intensity of synthesized light is monitored as needed, the positional information of a reflection point where the peak intensity of the synthesized light is substantially the same as the maximum peak intensity is obtained, and based on the positional information, the distance to a subject to be measured or the distance between two measuring points of the subject to be measured in the thickness direction is measured. Therefore, highly accurate distance measurement can be performed using coherent characteristics of laser beams in a relatively short time without requiring to obtain intensity data in a wide range.

Description

測距方法及びレーザ測距装置Ranging method and laser ranging device
　本発明は、レーザ光の干渉を用いて被測定物までの距離もしくは被測定物の測定点間の厚み方向の距離を測距する測距方法及びレーザ測距装置に関するものである。 The present invention relates to a distance measuring method and a laser distance measuring apparatus for measuring a distance to a measurement object or a distance in a thickness direction between measurement points of the measurement object using interference of a laser beam.
　従来のレーザ光を用いたレーザ測距方法は、例えばレーザ光を参照光と測定光とに分割し、その参照光と被測定物で反射された測定光との時間差から両者の光路差を求めることで被測定物までの距離を測定する。このような参照光と測定光との時間差から測距を行う従来のレーザ測距方法では、その測距精度はレーザ光の波長レベル、即ちｎｍ（ナノメートル）オーダーには遠く及ばない。 In a conventional laser distance measuring method using laser light, for example, the laser light is divided into reference light and measurement light, and the optical path difference between the reference light and measurement light reflected by the object to be measured is obtained. Measure the distance to the object to be measured. In the conventional laser distance measuring method that performs distance measurement based on the time difference between the reference light and the measurement light, the distance measurement accuracy is far from the wavelength level of the laser light, that is, the order of nm (nanometer).
　そこで本願発明者は下記［特許文献１］に示すように、波長の異なる複数のレーザ光を用い、さらにその光路差を変化させることでレーザ光の特徴である可干渉性を利用した高精度のレーザ測距方法及びレーザ測距装置に関する発明を行った。 Therefore, as shown in [Patent Document 1] below, the inventor of the present application uses a plurality of laser beams having different wavelengths, and further changes the optical path difference so as to utilize the coherence characteristic of the laser beams. Inventions related to a laser distance measuring method and a laser distance measuring apparatus were made.
国際公報第２００８／０９９７８８号パンフレットInternational Publication No. 2008/099788 Pamphlet
　［特許文献１］に開示された発明により被測定物までの距離を高精度に測距することが可能となったが、［特許文献１］に開示された発明では干渉光の明暗データ（強度データ）をある程度の範囲取得してその明暗データを基に測距を行うため、明暗データの取得に比較的時間を要するという問題点があった。 According to the invention disclosed in [Patent Document 1], the distance to the object to be measured can be measured with high accuracy. However, in the invention disclosed in [Patent Document 1], light / dark data (intensity of interference light) (Data) is acquired to some extent and distance measurement is performed based on the brightness data, so that it takes a relatively long time to acquire the brightness data.
　本発明は上記事情に鑑みてなされたものであり、比較的短時間で且つ高精度の測距が可能な測距方法及びレーザ測距装置を提供することを目的とする。 The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a distance measuring method and a laser distance measuring apparatus capable of measuring a distance with a high accuracy in a relatively short time.
　本発明は、
（１）異なる中心周波数を有し且つ特定の条件を満たす２つ乃至３つのレーザ光を参照光と測定光に分割し、全ての参照光をその光路長を変化させる方向に移動可能な反射点で反射させるとともに全ての測定光を被測定物６の測定点Ｓで反射させ、反射点で反射した各参照光と測定点で反射した各測定光とが合わさった合成光の強度データに基づいて被測定物６の測定点Ｓまでの距離を測定する測距方法であって、
当該合成光が、参照光の光路長と測定光の光路長とが等しくなる反射点の位置で最大ピーク強度をとるとともに、前記特定の条件が、前記最大ピーク強度を１００％としたときに強度データにおけるその他のピーク強度が最大ピーク強度の特定のパーセンテージを超えないことであり、
反射点の位置を移動させながら全てのレーザ光を照射してそのとき得られる合成光の強度データが最大ピーク強度と略同等のピーク強度をとる反射点の位置情報を記録する記録ステップと、
当該位置情報と予め取得されている基準点の位置情報とに基づいて基準点から測定点Ｓまでの距離を算出する測定ステップと、
を有することを特徴とする測距方法を提供することにより、上記課題を解決する。
（２）異なる中心周波数を有し且つ特定の条件を満たす２つ乃至３つのレーザ光を参照光と測定光に分割し、全ての測定光をさらに第１測定光と第２測定光とに分割し、全ての参照光をその光路長を変化させる方向に移動可能な反射点で反射させるとともに全ての第１測定光を被測定物６の第１測定点Ｓ１で反射させ、さらに全ての第２測定光を被測定物６の第２測定点Ｓ２で反射させ、反射点で反射した各参照光と第１測定点で反射した各第１測定光と第２測定点で反射した各第２測定光とが合わさった合成光の強度データに基づいて被測定物６の第１測定点Ｓ１と第２測定点Ｓ２との間の厚み方向の距離Ｌを測定する測距方法であって、
当該合成光が、参照光の光路長と第１測定光の光路長とが等しくなる反射点の第１位置Ｏ（Ｓ１）もしくは参照光の光路長と第２測定光の光路長とが等しくなる反射点の第２位置Ｏ（Ｓ２）で最大ピーク強度をとり、前記特定の条件が、前記最大ピーク強度を１００％としたときに強度データにおける第１位置Ｏ（Ｓ１）及び第２位置Ｏ（Ｓ２）以外の位置のピーク強度が最大ピーク強度の特定のパーセンテージを超えないことであり、
反射点の位置を移動させながら全てのレーザ光を照射してそのとき得られる合成光の強度データが最大ピーク強度と略同等のピーク強度をとる反射点の第１位置Ｏ（Ｓ１）の第１位置情報と第２位置Ｏ（Ｓ２）の第２位置情報とを記録する記録ステップと、
第１位置情報と第２位置情報とに基づいて第１測定点Ｓ１と第２測定点Ｓ２との間の厚み方向の距離Ｌを算出する測定ステップと、を有することを特徴とする測距方法を提供することにより、上記課題を解決する。
（３）無測定物状態で第１測定光の光路長及び第２測定光の光路長と参照光の光路長とが等しくなる反射点の位置Ｏを原点位置情報として記録する原点取得ステップをさらに有し、
第１測定光を被測定物６の第１測定点Ｓ１で反射させるとともに第２測定光を第１測定点Ｓ１の裏面に位置する第２測定点Ｓ２で反射させ、
測定ステップが第１位置情報と第２位置情報と原点位置情報とに基づいて被測定物６の厚みｔを算出することを特徴とする上記（２）記載の測距方法を提供することにより、上記課題を解決する。
（４）異なる中心周波数を有し且つ特定の条件を満たす２つ乃至３つのレーザ照射手段と、当該レーザ照射手段から出射した全てのレーザ光を参照光と測定光とに分割する分割部１２と、前記参照光を反射するとともに参照光の光路長が変化する方向に移動可能な反射部１４と、当該反射部１４の反射点の位置情報を取得する位置情報取得部２４と、反射部１４で反射した全ての参照光と被測定物６の測定点で反射した全ての測定光とを受光してその合成光の強度データを出力する受光部１８と、当該強度データに基づいて前記位置情報取得部２４から位置情報を取得しさらに所定の演算を行う演算部２０と、を備え、
前記特定の条件が、前記強度データにおける参照光の光路長と測定光の光路長とが等しくなる反射点の位置での最大ピーク強度を１００％としたときに強度データのその他のピーク強度が最大ピーク強度の特定のパーセンテージを超えないことであり、
上記（１）記載の記録ステップと測定ステップとを行い、予め設定されている基準点から測定点Ｓまでの距離を測距することを特徴とするレーザ測距装置５０ａ、５１ａを提供することにより、上記課題を解決する。
（５）異なる中心周波数を有し且つ特定の条件を満たす２つ乃至３つのレーザ照射手段と、当該レーザ照射手段から出射した全てのレーザ光を参照光と測定光とに分割する分割部１２と、前記参照光を反射するとともに参照光の光路長が変化する方向に移動可能な反射部１４と、当該反射部１４の反射点の位置情報を取得する位置情報取得部２４と、前記測定光を第１測定光と第２測定光とに分割する測定光分割部２８と、第１測定光を出射する第１出射口１６ａと第２測定光を出射する第２出射口１６ｂと、反射部１４で反射した全ての参照光と被測定物６の第１測定点Ｓ１で反射した全ての第１測定光と被測定物６の第２測定点Ｓ２で反射した全ての第２測定光とを受光してその合成光の強度データを出力する受光部１８と、当該強度データに基づいて前記位置情報取得部２４から第１位置情報と第２位置情報を取得しさらに所定の演算を行う演算部２０と、を備え、
前記特定の条件が、前記強度データにおける参照光の光路長と第１測定光の光路長とが等しくなる反射点の第１位置Ｏ（Ｓ１）もしくは参照光の光路長と第２測定光の光路長とが等しくなる反射点の第２位置Ｏ（Ｓ２）での最大ピーク強度を１００％としたときに強度データにおける第１位置Ｏ（Ｓ１）及び第２位置Ｏ（Ｓ２）以外の位置のピーク強度が最大ピーク強度の特定のパーセンテージを超えないことであり、
上記（２）記載の記録ステップと測定ステップとを行い第１測定点Ｓ１と第２測定点Ｓ２との間の厚み方向の距離Ｌを測距することを特徴とするレーザ測距装置５０ｂ、５１ｂを提供することにより、上記課題を解決する。
（６）異なる中心周波数を有し且つ特定の条件を満たす２つ乃至３つのレーザ照射手段と、当該レーザ照射手段から出射した全てのレーザ光を参照光と測定光とに分割する分割部１２と、前記参照光を反射するとともに参照光の光路長が変化する方向に移動可能な反射部１４と、当該反射部１４の反射点の位置情報を取得する位置情報取得部２４と、前記測定光を第１測定光と第２測定光とに分割する測定光分割部２８と、被測定物６の配置位置を挟んで対向する位置に設けられ第１測定光を出射する第１出射口１６ａと第２測定光を出射する第２出射口１６ｂと、反射部１４で反射した全ての参照光と被測定物６の第１測定点Ｓ１で反射した全ての第１測定光と第１測定点Ｓ１の裏面に位置する第２測定点Ｓ２で反射した全ての第２測定光とを受光してその合成光の強度データを出力する受光部１８と、当該強度データに基づいて前記位置情報取得部２４から第１位置情報と第２位置情報を取得しさらに所定の演算を行う演算部２０と、を備え、
前記特定の条件が、前記強度データにおける参照光の光路長と第１測定光の光路長とが等しくなる反射点の第１位置Ｏ（Ｓ１）もしくは参照光の光路長と第２測定光の光路長とが等しくなる反射点の第２位置Ｏ（Ｓ２）での最大ピーク強度を１００％としたときに強度データにおける第１位置Ｏ（Ｓ１）及び第２位置Ｏ（Ｓ２）以外の位置のピーク強度が最大ピーク強度の特定のパーセンテージを超えないことであり、
上記（３）記載の原点取得ステップと記録ステップと測定ステップとを行い被測定物６の厚みｔを測距することを特徴とするレーザ測距装置５０ｃ、５１ｃを提供することにより、上記課題を解決する。 The present invention
(1) Two or three laser beams that have different center frequencies and divide the reference beam and the measurement beam into the reference beam and the measurement beam, and all the reference beams can be moved in the direction of changing the optical path length. Based on the intensity data of the combined light in which all the measurement light is reflected at the measurement point S of the object 6 and the reference light reflected at the reflection point and the measurement light reflected at the measurement point are combined. A distance measuring method for measuring a distance to a measurement point S of a device under test 6, comprising:
The combined light has a maximum peak intensity at the position of the reflection point where the optical path length of the reference light and the optical path length of the measurement light are equal, and the specific condition is an intensity when the maximum peak intensity is 100%. The other peak intensities in the data do not exceed a certain percentage of the maximum peak intensity,
A recording step for recording the position information of the reflection point where the intensity data of the combined light obtained by irradiating all the laser beams while moving the position of the reflection point has a peak intensity substantially equal to the maximum peak intensity,
A measurement step for calculating a distance from the reference point to the measurement point S based on the position information and the position information of the reference point acquired in advance;
The above-described problem is solved by providing a distance measuring method characterized by comprising:
(2) Two to three laser beams having different center frequencies and satisfying a specific condition are divided into reference light and measurement light, and all measurement light is further divided into first measurement light and second measurement light. Then, all of the reference light is reflected at the reflection point that can move in the direction of changing the optical path length, and all of the first measurement light is reflected at the first measurement point S1 of the object 6 to be measured. The measurement light is reflected at the second measurement point S2 of the object 6 to be measured, each reference light reflected at the reflection point, each first measurement light reflected at the first measurement point, and each second measurement reflected at the second measurement point. A distance measuring method for measuring a distance L in the thickness direction between the first measurement point S1 and the second measurement point S2 of the object to be measured 6 based on the intensity data of the combined light combined with the light,
In the combined light, the first position O (S1) of the reflection point where the optical path length of the reference light and the optical path length of the first measurement light are equal, or the optical path length of the reference light and the optical path length of the second measurement light are equal. The maximum peak intensity is taken at the second position O (S2) of the reflection point, and the specific condition is that the first position O (S1) and the second position O (in the intensity data when the maximum peak intensity is 100%. The peak intensity at positions other than S2) does not exceed a certain percentage of the maximum peak intensity,
The first position O (S1) of the first position O (S1) of the reflection point where the intensity data of the combined light obtained by irradiating all the laser beams while moving the position of the reflection point has a peak intensity substantially equal to the maximum peak intensity. A recording step for recording the position information and the second position information of the second position O (S2);
A distance measuring method comprising: a measurement step of calculating a distance L in the thickness direction between the first measurement point S1 and the second measurement point S2 based on the first position information and the second position information. By providing the above, the above-described problems are solved.
(3) An origin acquisition step of recording, as origin position information, a reflection point position O where the optical path length of the first measurement light and the optical path length of the second measurement light and the optical path length of the reference light are equal in an unmeasured object state Have
The first measurement light is reflected at the first measurement point S1 of the object to be measured 6 and the second measurement light is reflected at the second measurement point S2 located on the back surface of the first measurement point S1,
By providing the distance measuring method according to (2) above, wherein the measuring step calculates the thickness t of the object 6 based on the first position information, the second position information, and the origin position information. Solve the above problems.
(4) Two to three laser irradiation means having different center frequencies and satisfying a specific condition, and a dividing unit 12 for dividing all the laser beams emitted from the laser irradiation means into reference light and measurement light The reflection unit 14 that reflects the reference light and can move in the direction in which the optical path length of the reference light changes, the position information acquisition unit 24 that acquires the position information of the reflection point of the reflection unit 14, and the reflection unit 14 The light receiving unit 18 that receives all reflected reference light and all measurement light reflected at the measurement point of the object 6 to be measured and outputs intensity data of the combined light, and obtains the position information based on the intensity data. And a calculation unit 20 that acquires position information from the unit 24 and performs a predetermined calculation.
When the specific condition is that the maximum peak intensity at the position of the reflection point where the optical path length of the reference light and the optical path length of the measurement light are equal in the intensity data is 100%, the other peak intensities of the intensity data are maximum. Not exceed a certain percentage of peak intensity,
By providing the laser distance measuring devices 50a and 51a, which perform the recording step and the measuring step described in (1) above, and measure the distance from a preset reference point to the measurement point S. Solve the above problems.
(5) Two to three laser irradiation units having different center frequencies and satisfying a specific condition, and a dividing unit 12 that divides all laser beams emitted from the laser irradiation units into reference light and measurement light The reflection unit 14 that reflects the reference light and is movable in the direction in which the optical path length of the reference light changes, the position information acquisition unit 24 that acquires the position information of the reflection point of the reflection unit 14, and the measurement light The measurement light dividing unit 28 that divides the first measurement light and the second measurement light, the first emission port 16a that emits the first measurement light, the second emission port 16b that emits the second measurement light, and the reflection unit 14 Receiving all of the reference light reflected by the first measurement light, all of the first measurement light reflected by the first measurement point S1 of the object 6 to be measured, and all of the second measurement light reflected by the second measurement point S2 of the object 6 to be measured. The light receiving unit 18 for outputting the intensity data of the combined light, and the intensity data It includes an arithmetic unit 20 for obtaining further predetermined operation of the first position information and second position information from the position information acquiring unit 24 based on the data, and
The specific condition is that the optical path length of the reference light and the optical path length of the first measurement light in the intensity data are equal to the first position O (S1) of the reflection point or the optical path length of the reference light and the optical path of the second measurement light. Peaks at positions other than the first position O (S1) and the second position O (S2) in the intensity data when the maximum peak intensity at the second position O (S2) of the reflection point having the same length is 100%. The intensity does not exceed a certain percentage of the maximum peak intensity,
Laser ranging devices 50b and 51b are characterized in that the recording step and the measuring step described in (2) are performed to measure the distance L in the thickness direction between the first measurement point S1 and the second measurement point S2. By providing the above, the above-described problems are solved.
(6) Two to three laser irradiation units having different center frequencies and satisfying a specific condition, and a dividing unit 12 that divides all laser beams emitted from the laser irradiation units into reference light and measurement light The reflection unit 14 that reflects the reference light and is movable in the direction in which the optical path length of the reference light changes, the position information acquisition unit 24 that acquires the position information of the reflection point of the reflection unit 14, and the measurement light A measurement light dividing unit 28 that divides the first measurement light and the second measurement light, a first emission port 16a that emits the first measurement light, provided at a position facing the arrangement position of the DUT 6 and the first measurement light. 2 of the second emission port 16b that emits the measurement light, all the reference light reflected by the reflection unit 14, and all the first measurement light and the first measurement point S1 reflected by the first measurement point S1 of the object 6 to be measured. All second measurement lights reflected at the second measurement point S2 located on the back surface Receiving light 18 and outputting intensity data of the combined light, and calculating the first position information and the second position information from the position information acquiring unit 24 based on the intensity data, and further performing a predetermined calculation Part 20, and
The specific condition is that the optical path length of the reference light and the optical path length of the first measurement light in the intensity data are equal to the first position O (S1) of the reflection point or the optical path length of the reference light and the optical path of the second measurement light. Peaks at positions other than the first position O (S1) and the second position O (S2) in the intensity data when the maximum peak intensity at the second position O (S2) of the reflection point having the same length is 100%. The intensity does not exceed a certain percentage of the maximum peak intensity,
By providing the laser distance measuring devices 50c and 51c that perform the origin acquisition step, the recording step, and the measurement step described in the above (3) and measure the thickness t of the object 6 to be measured, Resolve.
　本発明に係る測距方法及びレーザ測距装置によれば、比較的短時間で被測定物までの距離もしくは被測定物の２つの測定点間の厚み方向の距離を高精度に測定することができる。 According to the distance measuring method and the laser distance measuring device according to the present invention, the distance to the object to be measured or the distance in the thickness direction between two measurement points of the object to be measured can be measured with high accuracy in a relatively short time. it can.
本発明に係る第１の形態のレーザ測距装置の概略構成を示す図である。It is a figure which shows schematic structure of the laser ranging apparatus of the 1st form which concerns on this invention. レーザ照射手段の選定を説明する図である。It is a figure explaining selection of a laser irradiation means. 本発明に係る第１の形態のレーザ測距装置の変形例の概略構成を示す図である。It is a figure which shows schematic structure of the modification of the laser range finder of the 1st form which concerns on this invention. 本発明に係る第１の形態のレーザ測距装置の使用例を示す図である。It is a figure which shows the usage example of the laser distance measuring device of the 1st form which concerns on this invention. 本発明に係る第２の形態のレーザ測距装置の概略構成を示す図である。It is a figure which shows schematic structure of the laser ranging apparatus of the 2nd form which concerns on this invention. 本発明に係る第３の形態のレーザ測距装置の概略構成を示す図である。It is a figure which shows schematic structure of the laser ranging apparatus of the 3rd form which concerns on this invention. 本発明に係るレーザ測距装置の変形例の概略構成を示す図である。It is a figure which shows schematic structure of the modification of the laser ranging apparatus which concerns on this invention. 本発明に係る第３の形態のレーザ測距装置の変形例の概略構成を示す図である。It is a figure which shows schematic structure of the modification of the laser ranging apparatus of the 3rd form which concerns on this invention.
　本発明に係る測距方法及びレーザ測距装置の実施の形態について図面に基づいて説明する。 Embodiments of a distance measuring method and a laser distance measuring device according to the present invention will be described with reference to the drawings.
　図１に本発明に係る第１の形態のレーザ測距装置５０ａを示す。尚、図１、図３～図７中の破線はレーザ光の光路を示す。図１に示す本発明に係るレーザ測距装置５０ａは、異なる中心周波数を有し且つ後述する特定の条件を満たす２つのレーザ光（第１レーザ光、第２レーザ光）をそれぞれ出射する第１レーザ照射手段１０ａと第２レーザ照射手段１０ｂとを有している。 FIG. 1 shows a laser range finder 50a according to a first embodiment of the present invention. The broken lines in FIGS. 1 and 3 to 7 indicate the optical path of the laser beam. A laser distance measuring device 50a according to the present invention shown in FIG. 1 emits two laser beams (first laser beam and second laser beam) having different center frequencies and satisfying specific conditions described later. It has laser irradiation means 10a and second laser irradiation means 10b.
　第１レーザ照射手段１０ａ、第２レーザ照射手段１０ｂ、及び後述する第３レーザ照射手段１０ｃの種類に関しては後述する特定の条件を満たす限り特に限定はなく、ヘリウムネオンレーザやアルゴンレーザ、クリプトンイオンレーザ、ヘリウムカドミウムレーザ等のガスレーザ、ルビーレーザやＹＡＧレーザ等の固体レーザ、金属レーザ、半導体レーザ等を用いることができる。この中でも周波数分布が比較的ブロードな多縦モード発振のレーザ照射手段を用いることが好ましい。尚、多縦モード発振のレーザ光とは発振するレーザ光の周波数分布がブロードなものを指し、ここでは性能や安定性、バラつき等により結果として周波数分布が広がっているものもこれに含めるものとする。従って、レーザ測距装置５０ａ、及び後述のレーザ測距装置５０ｂ、５０ｃ、５１ａ、５１ｂ、５１ｃでは、高い周波数安定性や安定した発光スペクトルを有する高価なレーザ照射手段を必ずしも必要とせず、周波数や発光スペクトルの安定性が比較的劣った安価なレーザ照射手段を使用することができる。よって、使用するレーザ照射手段としては、安価な半導体レーザを用いることが特に好ましい。半導体レーザを使用することにより、レーザ測距装置５０ａ～５１ｃの部品コストを削減することが可能となりレーザ測距装置５０ａ～５１ｃをより安価に提供することができる。尚、使用するレーザ照射手段のうち少なくとも１つのレーザ照射手段を４００ｎｍ～７５０ｎｍの可視光領域の発振波長を有するものとすれば、レーザ光の照射位置が目視可能となり作業性の向上を図ることができる。 The types of the first laser irradiation unit 10a, the second laser irradiation unit 10b, and the third laser irradiation unit 10c to be described later are not particularly limited as long as specific conditions described later are satisfied, and helium neon laser, argon laser, krypton ion laser. A gas laser such as a helium cadmium laser, a solid laser such as a ruby laser or a YAG laser, a metal laser, a semiconductor laser, or the like can be used. Among these, it is preferable to use a laser irradiation means of multi-longitudinal mode oscillation having a relatively broad frequency distribution. The laser beam of multi-longitudinal mode oscillation means that the frequency distribution of the oscillating laser beam is broad, and this includes the one whose frequency distribution is broadened as a result of performance, stability, variation, etc. To do. Therefore, the laser distance measuring device 50a and the laser distance measuring devices 50b, 50c, 51a, 51b, 51c described later do not necessarily require expensive laser irradiation means having high frequency stability and a stable emission spectrum. An inexpensive laser irradiation means with relatively inferior emission spectrum stability can be used. Therefore, it is particularly preferable to use an inexpensive semiconductor laser as the laser irradiation means to be used. By using the semiconductor laser, it is possible to reduce the component costs of the laser distance measuring devices 50a to 51c, and to provide the laser distance measuring devices 50a to 51c at a lower cost. If at least one of the laser irradiation means to be used has an oscillation wavelength in the visible light region of 400 nm to 750 nm, the irradiation position of the laser light can be seen and the workability can be improved. it can.
　第１レーザ照射手段１０ａから出射した第１レーザ光は、第１レーザ光の光路上に設けられたミラー４ａで反射され分割部１２に向う。また、第２レーザ照射手段１０ｂから出射した第２レーザ光は、第２レーザ光の光路上に設けられたハーフミラー４ｂで反射され第１レーザ光と同一光路上を通り分割部１２に向う。 The first laser light emitted from the first laser irradiation means 10a is reflected by the mirror 4a provided on the optical path of the first laser light and travels toward the dividing section 12. The second laser light emitted from the second laser irradiation means 10b is reflected by the half mirror 4b provided on the optical path of the second laser light, passes through the same optical path as the first laser light, and travels to the dividing unit 12.
　分割部１２としてはハーフミラーやビームスプリッタ等が用いられ、分割部１２に到達した第１レーザ光及び第２レーザ光は分割部１２の分割点で２分割される。そして、一方は参照光として反射部１４に向かい、もう一方は測定光として被測定物６の側に向う。 A half mirror, a beam splitter, or the like is used as the dividing unit 12, and the first laser beam and the second laser beam that have reached the dividing unit 12 are divided into two at the dividing point of the dividing unit 12. One is directed to the reflecting portion 14 as reference light, and the other is directed to the measured object 6 side as measurement light.
　分割部１２で分割された第１レーザ光及び第２レーザ光の参照光は反射部１４の反射点にて反射され、分割部１２を通過して受光部１８に到達する。尚、反射部１４には移動手段２２が設置されており、移動手段２２の動作により反射部１４は反射点から分割点までの距離、即ち参照光の光路長が変化する方向に移動する。 The reference light of the first laser beam and the second laser beam divided by the dividing unit 12 is reflected at the reflection point of the reflecting unit 14, passes through the dividing unit 12, and reaches the light receiving unit 18. In addition, the moving unit 22 is installed in the reflecting unit 14, and the reflecting unit 14 moves in a direction in which the distance from the reflecting point to the dividing point, that is, the optical path length of the reference light is changed by the operation of the moving unit 22.
　位置情報取得部２４は、図示しない装置制御部からの信号を受けて移動手段２２を動作させるとともに、移動手段２２の動作によって変化する反射点の位置情報を演算部２０に出力する。尚、移動手段２２としては１ステップで５～１０ｎｍ程度移動する摺動型超音波モータ等を用いることが好ましい。また、反射部１４と反射点とは固定であり、本願では反射点の絶対位置よりも相対位置が重要であるから、反射点の位置情報は反射部１４の位置情報で間接的に代用することも可能である。 The position information acquisition unit 24 operates a moving unit 22 in response to a signal from a device control unit (not shown), and outputs position information of a reflection point that is changed by the operation of the moving unit 22 to the calculation unit 20. As the moving means 22, it is preferable to use a sliding ultrasonic motor or the like that moves about 5 to 10 nm in one step. In addition, since the reflection part 14 and the reflection point are fixed, and the relative position is more important than the absolute position of the reflection point in the present application, the position information of the reflection point is indirectly substituted with the position information of the reflection part 14. Is also possible.
　分割部１２で分割された第１レーザ光及び第２レーザ光の測定光は出射口１６から出射する。そして、図１（ｂ）に示すように、出射口１６から出射した第１レーザ光及び第２レーザ光の測定光は被測定物６の測定点Ｓで反射され分割部１２を経由して受光部１８に到達する。 The measurement light of the first laser beam and the second laser beam divided by the dividing unit 12 is emitted from the emission port 16. Then, as shown in FIG. 1B, the measurement light of the first laser light and the second laser light emitted from the emission port 16 is reflected at the measurement point S of the object 6 to be received via the dividing unit 12. Part 18 is reached.
　受光部１８は、測定点Ｓで反射した第１レーザ光及び第２レーザ光の測定光と反射点で反射した第１レーザ光及び第２レーザ光の参照光とを受光して、これらの光が全て合わさった合成光の強度データを電気信号に変換し演算部２０に出力する。 The light receiving unit 18 receives the measurement light of the first laser light and the second laser light reflected at the measurement point S and the reference light of the first laser light and the second laser light reflected at the reflection point, and receives these lights. The combined intensity data of the combined light is converted into an electrical signal and output to the arithmetic unit 20.
　このとき、位置情報取得部２４が移動手段２２を動作させ反射点の位置を参照光の光路長が変化する方向に移動させる。参照光の光路長が変化すると参照光と測定光の光路差が変化し、これに伴って受光部１８が出力する合成光の強度データも変化する。 At this time, the position information acquisition unit 24 operates the moving unit 22 to move the position of the reflection point in the direction in which the optical path length of the reference light changes. When the optical path length of the reference light changes, the optical path difference between the reference light and the measurement light changes, and the intensity data of the combined light output from the light receiving unit 18 changes accordingly.
　演算部２０は合成光の強度データが所定の条件を満たす場合、そのときの反射点の位置情報を位置情報取得部２４から取得した上で後述の演算を行う。 When the intensity data of the combined light satisfies a predetermined condition, the calculation unit 20 acquires the position information of the reflection point at that time from the position information acquisition unit 24 and performs the calculation described later.
　ここで、第１レーザ光及び第２レーザ光が満たすべき特定の条件に関して説明する。先ず、参照光の光路長と測定光の光路長とが等しく光路差が存在しない場合には、どのような発振波長を有するレーザ光であってもその参照光と測定光とは強め合いその干渉光は明部のピークをとる。つまり、出力電圧、温度、レーザ照射手段自体のブレなどにより、レーザ照射手段が出射するレーザ光の周波数が変化したとしても、参照光と測定光とに光路差が存在しない点ではその干渉光は明部のピークを常に維持する。反対に参照光と測定光とに光路差が存在する場合には、異なる発振波長を有するレーザ光の干渉光が同時に明部をとるような光路差の値は現実には存在しない。従って、反射点の位置と干渉光の強度との関係を模式的に示した図２（ａ）にあるように、第１レーザ光の測定光と第１レーザ光の参照光とが干渉して生じる干渉光（図２（ａ）中の（Ａ））と、第２レーザ光の測定光と第２レーザ光の参照光とが干渉して生じる干渉光（図２（ａ）中の（Ｂ））とは参照光の光路長と測定光の光路長とが等しい反射点の位置Ｏにおいて双方とも明部のピークを取り、これらの合成光（図２（ａ）中の（Ｃ））の強度は最大のピーク強度をとる。そして、第１レーザ光による干渉光（Ａ）と第２レーザ光による干渉光（Ｂ）とのピーク位置が完全に一致する点は位置Ｏ以外には存在しない。従って、これらの合成光には位置Ｏ以外に最大ピーク強度以上のピーク強度をとる位置は存在しない。 Here, a specific condition to be satisfied by the first laser beam and the second laser beam will be described. First, when the optical path length of the reference light and the optical path length of the measurement light are equal and there is no optical path difference, the reference light and the measurement light are intensified and interfered with any laser light having any oscillation wavelength. The light has a bright peak. In other words, even if the frequency of the laser beam emitted from the laser irradiation unit changes due to the output voltage, temperature, vibration of the laser irradiation unit itself, etc., the interference light does not exist in that there is no optical path difference between the reference beam and the measurement beam. Always keep the bright peaks. On the other hand, when there is an optical path difference between the reference light and the measurement light, there is actually no optical path difference value at which the interference light of the laser light having different oscillation wavelengths simultaneously takes a bright portion. Therefore, as shown in FIG. 2A schematically showing the relationship between the position of the reflection point and the intensity of the interference light, the measurement light of the first laser light interferes with the reference light of the first laser light. The generated interference light ((A) in FIG. 2A) interferes with the measurement light of the second laser light and the reference light of the second laser light ((B in FIG. 2A). )) Both take a bright peak at a reflection point position O where the optical path length of the reference light and the optical path length of the measurement light are equal, and the combined light ((C) in FIG. 2A). The intensity takes the maximum peak intensity. Further, there is no point other than the position O where the peak positions of the interference light (A) by the first laser light and the interference light (B) by the second laser light completely coincide. Therefore, in these synthesized lights, there is no position having a peak intensity equal to or greater than the maximum peak intensity other than the position O.
　しかしながら、干渉光のピークの周期はレーザ光の周波数に依存するため、第１レーザ光による干渉光（Ａ）のピークと第２レーザ光による干渉光（Ｂ）のピークとが近接する場合（例えば図２中の位置Ｏ’）が存在する。干渉光（Ａ）のピークと第２レーザ光による干渉光（Ｂ）のピークとが近接している位置では、その合成光のピーク強度が最大ピーク強度に近づく可能性があり、このような場合、演算部２０が位置Ｏ’を位置Ｏと誤認識する虞がある。従って、第１レーザ照射手段１０ａと第２レーザ照射手段１０ｂとは、参照光の光路長と測定光の光路長とが等しい反射点の位置Ｏにおける最大ピーク強度を１００％としたときに、合成光の強度データにおける位置Ｏ以外のピーク強度が最大ピーク強度の特定のパーセンテージを超えないような組み合わせを選択しなければならない。この特定のパーセンテージの値は、演算部２０が最大ピーク強度とその他のピーク強度とを判別するのに十分な値とし、例えばレーザ光を２つ使用する場合には約８０％～９８％の範囲の値で好適には９７％であり、後述のレーザ光を３つ使用する場合には約６０％～９７％の範囲の値で好適には９０％である。尚、このパーセンテージの値は、小さくなれば演算部２０によるピークの判別が容易となるが、レーザ照射手段の選択の自由度が減少する。また、１００％に近づけばレーザ照射手段の選択の幅は広がるが、演算部２０によるピークの判別が困難となる。尚、図２の位置Ｏ’は例であり、必ずしも位置Ｏの隣に位置Ｏ’が来るとは限らない。 However, since the period of the peak of the interference light depends on the frequency of the laser light, the peak of the interference light (A) due to the first laser light and the peak of the interference light (B) due to the second laser light are close (for example, A position O ′) in FIG. 2 exists. At the position where the peak of the interference light (A) and the peak of the interference light (B) by the second laser light are close, the peak intensity of the combined light may approach the maximum peak intensity. The calculation unit 20 may erroneously recognize the position O ′ as the position O. Therefore, the first laser irradiation unit 10a and the second laser irradiation unit 10b are combined when the maximum peak intensity at the position O of the reflection point where the optical path length of the reference light and the optical path length of the measurement light are equal is 100%. A combination must be selected such that the peak intensities other than position O in the light intensity data do not exceed a certain percentage of the maximum peak intensity. This specific percentage value is a value sufficient for the calculation unit 20 to distinguish between the maximum peak intensity and the other peak intensities. For example, when two laser beams are used, the range is about 80% to 98%. The value is preferably 97%, and in the case of using three laser beams described later, the value is in the range of about 60% to 97%, preferably 90%. If the percentage value is reduced, the peak can be easily determined by the calculation unit 20, but the degree of freedom in selecting the laser irradiation means is reduced. Further, if it approaches 100%, the selection range of the laser irradiation means is widened, but it is difficult to determine the peak by the calculation unit 20. Note that the position O ′ in FIG. 2 is an example, and the position O ′ does not necessarily come next to the position O.
　また、レーザ照射手段が発するレーザ光は、発振特性、動作出力、装置構成、個々のバラつき等により周波数分布やその安定性が変化する。特に、安価な半導体レーザはその傾向が顕著である。また、上記の特定の条件を満たすか否かはレーザ光の中心周波数のみならず周波数分布にも左右される。従って、第１レーザ照射手段１０ａ、第２レーザ照射手段１０ｂの選定は、選択した第１レーザ照射手段１０ａ、第２レーザ照射手段１０ｂをレーザ測距装置５０ａに実際に搭載して実際の使用条件で確認した上で行うことが好ましい。 Also, the frequency distribution and stability of the laser light emitted by the laser irradiation means vary depending on the oscillation characteristics, operation output, device configuration, individual variations, and the like. This tendency is particularly noticeable for inexpensive semiconductor lasers. Whether or not the above specific condition is satisfied depends not only on the center frequency of the laser beam but also on the frequency distribution. Therefore, the selection of the first laser irradiation means 10a and the second laser irradiation means 10b is performed by actually mounting the selected first laser irradiation means 10a and second laser irradiation means 10b on the laser distance measuring device 50a. It is preferable to carry out after confirming.
　ここで、第１レーザ照射手段１０ａ、第２レーザ照射手段１０ｂの選定方法の例を説明する。尚、以後はこの特定のパーセンテージの値を９５％として説明を行うものとする。 Here, an example of a selection method of the first laser irradiation unit 10a and the second laser irradiation unit 10b will be described. In the following description, the specific percentage value is assumed to be 95%.
　先ず、選定する第１レーザ照射手段１０ａ、第２レーザ照射手段１０ｂをレーザ測距装置５０ａに搭載する。次に、図１（ａ）に示すように、出射口１６を表面が平滑なシャッタ５で塞ぐ。 First, the first laser irradiation means 10a and the second laser irradiation means 10b to be selected are mounted on the laser distance measuring device 50a. Next, as shown in FIG. 1A, the exit port 16 is closed with a shutter 5 having a smooth surface.
　そして、移動手段２２を動作させて反射部１４を所定の範囲内で移動させながら第１レーザ光及び第２レーザ光を同時に照射する。これにより、受光部１８は反射点で反射した各参照光とシャッタ５の反射点Ｓ’で反射した各測定光を受光して、これらの合成光の強度データを出力する。 Then, the moving means 22 is operated to simultaneously irradiate the first laser beam and the second laser beam while moving the reflecting portion 14 within a predetermined range. As a result, the light receiving unit 18 receives each reference light reflected by the reflection point and each measurement light reflected by the reflection point S ′ of the shutter 5, and outputs intensity data of these combined lights.
　ここで、分割点から反射点までの距離を距離Ｌｒ（ｓ’）とし、分割点からシャッタ５の反射点Ｓ’までの距離を距離Ｌｍ（ｓ’）とし、距離Ｌｒ（ｓ’）と距離Ｌｍ（ｓ’）とが等しい反射点の位置を位置Ｏ（ｓ’）とし、第１レーザ光もしくは第２レーザ光のコヒーレンス長をＬｃとした場合、上記の反射部１４の移動範囲は位置Ｏ（ｓ’）を中心とした　Ｏ（ｓ’）±（Ｌｃ／２）　の範囲とすることが好ましい。尚、現段階では位置Ｏ（ｓ’）は高精度に特定できていないが、レーザ照射手段の選定時においては特に問題は生じない。 Here, the distance from the division point to the reflection point is a distance Lr (s ′), the distance from the division point to the reflection point S ′ of the shutter 5 is a distance Lm (s ′), and the distance Lr (s ′) and the distance When the position of the reflection point equal to Lm (s ′) is the position O (s ′) and the coherence length of the first laser beam or the second laser beam is Lc, the movement range of the reflection unit 14 is the position O. A range of O (s ′) ± (Lc / 2) centered on (s ′) is preferable. At this stage, the position O (s') cannot be specified with high accuracy, but no particular problem occurs when the laser irradiation means is selected.
　上記のようにして得られた強度データは、距離Ｌｒ（ｓ’）と距離Ｌｍ（ｓ’）とが合致する位置Ｏ（ｓ’）において最大ピーク強度をとる。また、強度データは最大ピーク強度以外にも第１レーザ光による干渉光のピークと第２レーザ光による干渉光のピークとに応じた強度のピークをとる。そして、これらの強度データのピーク強度を確認し、このうちの最大ピーク強度（位置Ｏ（ｓ’））の値を取得する。尚、最大ピーク強度の値は第１レーザ照射手段１０ａ、第２レーザ照射手段１０ｂの出力変動などにより上下する可能性がある。このような場合、この位置（位置Ｏ（ｓ’））でのピーク強度の平均値を最大ピーク強度としても良い。 The intensity data obtained as described above takes the maximum peak intensity at the position O (s') where the distance Lr (s') and the distance Lm (s') match. In addition to the maximum peak intensity, the intensity data takes an intensity peak corresponding to the peak of the interference light by the first laser light and the peak of the interference light by the second laser light. Then, the peak intensity of these intensity data is confirmed, and the value of the maximum peak intensity (position O (s ′)) is obtained. Note that there is a possibility that the value of the maximum peak intensity will fluctuate due to output fluctuations of the first laser irradiation means 10a and the second laser irradiation means 10b. In such a case, an average value of peak intensities at this position (position O (s ′)) may be set as the maximum peak intensity.
　そして、この最大ピーク強度を１００％としたときに、その他の全てのピーク強度がレーザ照射手段の出力変動を加味したとしても最大ピーク強度の９５％に満たない場合、この第１レーザ照射手段１０ａと第２レーザ照射手段１０ｂとの組み合わせを採用可能と判断する。そして、演算部２０はこのときの最大ピーク強度の９５％の値を判定基準として図示しないメモリ等に記録する。逆に、その他のピーク強度にレーザ照射手段の出力変動を含めて最大ピーク強度の９５％を超えるものが存在する場合、新たに第１レーザ照射手段１０ａ、第２レーザ照射手段１０ｂの組み合わせを選定する。 When the maximum peak intensity is 100%, if all other peak intensities are less than 95% of the maximum peak intensity even if the output fluctuation of the laser irradiation means is taken into account, the first laser irradiation means 10a. And the second laser irradiation means 10b are determined to be adoptable. Then, the calculation unit 20 records a value of 95% of the maximum peak intensity at this time as a determination criterion in a memory or the like (not shown). On the other hand, when there are other peak intensities that exceed 95% of the maximum peak intensity including the output fluctuation of the laser irradiation means, a new combination of the first laser irradiation means 10a and the second laser irradiation means 10b is selected. To do.
　尚、参照光と測定光との光路差がコヒーレンス長を超えたレーザ光は干渉することはない。従って、上記の移動範囲を超えた領域では干渉光は形成されず合成光に明確なピークは出現しなくなる。よって、上記の移動範囲を超えた領域の強度データを確認する必要は無い。また、図２に示すように、干渉光のピークは位置Ｏから離れるに従ってブロードとなり、その分だけピーク強度が減少する。よって、ある程度以上の距離だけ位置Ｏから離れれば第１レーザ光による干渉光と第２レーザ光による干渉光のピーク位置が極めて近接してもそのピーク強度は最大ピーク強度の９５％に満たなくなる。よって、使用するレーザ照射手段によっては上記の移動範囲をさらに位置Ｏ（ｓ’）を中心とした前後（Ｌｃ／４）程度にまで狭めることができる。以上のレーザ照射手段の選定は、後述のレーザ測距装置５０ｂ、５０ｃでも基本的に同様である。ただし、レーザ測距装置５０ｂ、５０ｃでは上記のレーザ照射手段の選定を、第１測定光、第２測定光のうち一方を遮蔽して行うようにする。 Note that laser light whose optical path difference between the reference light and the measurement light exceeds the coherence length does not interfere. Therefore, no interference light is formed in the region exceeding the above moving range, and no clear peak appears in the synthesized light. Therefore, there is no need to confirm the intensity data of the area beyond the moving range. Further, as shown in FIG. 2, the peak of the interference light becomes broader as the distance from the position O increases, and the peak intensity decreases accordingly. Therefore, if the distance from the position O is more than a certain distance, even if the peak positions of the interference light by the first laser light and the interference light by the second laser light are very close, the peak intensity is less than 95% of the maximum peak intensity. Therefore, depending on the laser irradiation means to be used, the above moving range can be further reduced to about (Lc / 4) around the position O (s ′). The selection of the laser irradiation means described above is basically the same in the laser distance measuring devices 50b and 50c described later. However, in the laser distance measuring devices 50b and 50c, the above laser irradiation means is selected by shielding one of the first measurement light and the second measurement light.
　また、最適な第１レーザ照射手段１０ａ、第２レーザ照射手段１０ｂの選定が困難な場合、図３（ａ）のレーザ測距装置５１ａ及び図７のレーザ測距装置５１ｂ、５１ｃに示すように、第１レーザ光及び第２レーザ光とは中心周波数の異なる第３レーザ照射手段１０ｃを設けても良い。第３レーザ照射手段１０ｃを設けることにより、第３レーザ光による干渉光が生じ、この第３レーザ光による干渉光は第１レーザ光による干渉光、第２レーザ光による干渉光と同様、位置Ｏで明部のピークをとる。しかしながら、位置Ｏ以外で第３レーザ光による干渉光、第１レーザ光による干渉光、第２レーザ光による干渉光のピークが全て近接する確率は２つのレーザ光を用いたときと比べて著しく低い。よって、第３レーザ照射手段１０ｃを設けることにより、レーザ照射手段の選定の自由度を拡げることができる。また、第３レーザ照射手段１０ｃを設けることにより、最大ピーク強度の値とその他のピーク強度の値との差が２つのレーザ光を用いたときと比べて拡大するため演算部２０によるピーク強度の識別をより容易に行うことができる。 If it is difficult to select the optimal first laser irradiation means 10a and second laser irradiation means 10b, as shown in the laser distance measuring device 51a in FIG. 3A and the laser distance measuring devices 51b and 51c in FIG. A third laser irradiation means 10c having a different center frequency from the first laser light and the second laser light may be provided. By providing the third laser irradiation means 10c, interference light due to the third laser light is generated, and the interference light due to the third laser light is located at the position O similarly to the interference light due to the first laser light and the interference light due to the second laser light. Take the peak of the bright part. However, the probability that the interference light beams by the third laser light, the interference light by the first laser light, and the interference light by the second laser light are all close except at the position O is significantly lower than when two laser lights are used. . Therefore, by providing the third laser irradiation means 10c, the degree of freedom in selecting the laser irradiation means can be expanded. Further, by providing the third laser irradiation means 10c, the difference between the maximum peak intensity value and the other peak intensity values is increased compared with the case where two laser beams are used. Identification can be performed more easily.
　尚、第３レーザ照射手段１０ｃの選定は、図２（ｂ）に示すように、第３レーザ光による干渉光（図２（ｂ）中の（Ｄ））の２つの明部のピークが、２レーザ時の最大ピーク強度の９５％を超えるピーク強度の位置（例えば図２（ａ）における位置Ｏ’）を挟むように選定することが好ましい。 As shown in FIG. 2B, the selection of the third laser irradiation means 10c is such that the peaks of the two bright parts of the interference light ((D) in FIG. 2B) by the third laser light are It is preferable to select so as to sandwich the position of the peak intensity exceeding 95% of the maximum peak intensity at the time of two lasers (for example, the position O ′ in FIG. 2A).
　また、３つのレーザ照射手段の選定は、第１レーザ光の中心周波数をλａ、第２レーザ光の中心周波数をλｂ、第３レーザ光の中心周波数をλｃとし、
λａ＜λｂ＜λｃ　としたときに
３×λａ＜λｃ　を満たすことを目安とすれば良い。 The selection of the three laser irradiation means is to set the center frequency of the first laser light as λa, the center frequency of the second laser light as λb, and the center frequency of the third laser light as λc,
As a guideline, 3 × λa <λc may be satisfied when λa <λb <λc.
　次に、本発明に係る第１の測距方法をレーザ測距装置５０ａの動作とともに説明する。尚、レーザ照射手段を３つ有するレーザ測距装置５１ａも基本動作は全く同じである。 Next, the first distance measuring method according to the present invention will be described together with the operation of the laser distance measuring device 50a. The basic operation of the laser distance measuring device 51a having three laser irradiation means is exactly the same.
　本発明に係る第１の測距方法では、予め基準点の位置情報を取得する必要がある。よって、ここでは先ずシャッタ５の反射点Ｓ’を基準点としてこの基準点の位置情報を取得する方法を説明する。尚、ここでの基準点の位置情報の取得方法は、基本的に第１の測距方法及びレーザ測距装置５０ａの動作と同等である。 In the first distance measuring method according to the present invention, it is necessary to obtain reference point position information in advance. Therefore, here, a method of acquiring position information of the reference point using the reflection point S ′ of the shutter 5 as a reference point will be described first. The reference point position information acquisition method here is basically the same as the first distance measurement method and the operation of the laser distance measuring device 50a.
　先ず、図１（ａ）に示すように、出射口１６をシャッタ５で塞ぐ。次に、反射部１４の反射点を起点位置に位置させる。ここでの起点位置は分割点から出射口１６までの距離と等しい反射点の位置とすることが好ましい。次に、第１レーザ照射手段１０ａ、第２レーザ照射手段１０ｂを動作させ第１レーザ光及び第２レーザ光を同時に照射する。これにより、受光部１８は反射点で反射された各レーザ光の参照光とシャッタ５の反射点Ｓ’で反射された各レーザ光の測定光とを受光して、これらの合成光の強度データを演算部２０に出力する。また、位置情報取得部２４は移動手段２２を動作させ、反射点を反射部１４ごと参照光の光路長が増加する方向に移動させる。 First, as shown in FIG. 1A, the exit port 16 is closed with the shutter 5. Next, the reflection point of the reflection unit 14 is positioned at the starting position. Here, the starting point position is preferably a reflection point position equal to the distance from the dividing point to the exit port 16. Next, the first laser irradiation unit 10a and the second laser irradiation unit 10b are operated to irradiate the first laser beam and the second laser beam simultaneously. Thereby, the light receiving unit 18 receives the reference light of each laser beam reflected at the reflection point and the measurement light of each laser beam reflected at the reflection point S ′ of the shutter 5, and intensity data of these combined lights Is output to the arithmetic unit 20. Further, the position information acquisition unit 24 operates the moving unit 22 to move the reflection point together with the reflection unit 14 in the direction in which the optical path length of the reference light increases.
　ここで、反射点が移動して距離Ｌｒ（ｓ’）が距離Ｌｍ（ｓ’）と等しい位置Ｏ（ｓ’）となると、測定光の光路長２×Ｌｍ（ｓ’）と参照光の光路長２×Ｌｒ（ｓ’）とが等しくなる。従って、この位置Ｏ（ｓ’）において合成光の強度は最大ピーク強度をとる。 Here, when the reflection point moves and the distance Lr (s ′) reaches the position O (s ′) equal to the distance Lm (s ′), the optical path length of the measurement light 2 × Lm (s ′) and the optical path of the reference light The length 2 × Lr (s ′) is equal. Therefore, the intensity of the synthesized light takes the maximum peak intensity at this position O (s ′).
　演算部２０は受光部１８からの合成光の強度がレーザ照射手段の出力変動を加味した上での判定基準（ここでは、最大ピーク強度の９５％）を超えるか否かを随時モニタする。そして、反射点の位置が位置Ｏ（ｓ’）に接近して合成光の強度が判定基準を超えた場合、演算部２０は判定基準を満たす範囲内で最大の強度をとる反射点の位置、即ち最大ピーク強度をとる反射点の位置情報を位置情報取得部２４から取得して基準点の位置情報として記録する。尚、この基準点の位置は、図１（ａ）においては位置Ｏ（ｓ’）に相当する。 The calculation unit 20 monitors at any time whether or not the intensity of the combined light from the light receiving unit 18 exceeds a criterion (95% of the maximum peak intensity) in consideration of output fluctuation of the laser irradiation means. When the position of the reflection point approaches the position O (s ′) and the intensity of the combined light exceeds the determination criterion, the calculation unit 20 has the position of the reflection point that takes the maximum intensity within a range that satisfies the determination criterion. That is, the position information of the reflection point having the maximum peak intensity is acquired from the position information acquisition unit 24 and recorded as the position information of the reference point. Note that the position of this reference point corresponds to the position O (s ′) in FIG.
　次に、被測定物６の測定点Ｓまでの距離を測定する。先ず、シャッタ５を除くとともに被測定物６を設置して第１レーザ光及び第２レーザ光の測定光を被測定物６の測定点Ｓで反射させる。これにより、受光部１８は反射点で反射された各レーザ光の参照光と被測定物６の測定点Ｓで反射された各レーザ光の測定光とを受光して、これらの合成光の強度データを演算部２０に出力する。また、位置情報取得部２４は移動手段２２を動作させ、反射点を参照光の光路長が増加する方向にさらに移動させる。 Next, the distance to the measurement point S of the DUT 6 is measured. First, the measurement object 6 is installed while removing the shutter 5, and the measurement light of the first laser light and the second laser light is reflected at the measurement point S of the measurement object 6. Thereby, the light receiving unit 18 receives the reference light of each laser beam reflected at the reflection point and the measurement light of each laser beam reflected at the measurement point S of the object 6 to be measured, and the intensity of the combined light. Data is output to the arithmetic unit 20. In addition, the position information acquisition unit 24 operates the moving unit 22 to further move the reflection point in the direction in which the optical path length of the reference light increases.
　ここで、分割点から測定点Ｓまでの距離を距離Ｌｍ（ｓ）とし、分割点から反射点までの距離を距離Ｌｒ（ｓ）とすると、反射点が移動して距離Ｌｒ（ｓ）が距離Ｌｍ（ｓ）と等しい位置Ｏ（ｓ）に到達した時に、測定光の光路長２×Ｌｍ（ｓ）と参照光の光路長２×Ｌｒ（ｓ）とが等しくなる。従って、この位置Ｏ（ｓ）において合成光の強度は最大ピーク強度をとる。 Here, when the distance from the division point to the measurement point S is the distance Lm (s) and the distance from the division point to the reflection point is the distance Lr (s), the reflection point moves and the distance Lr (s) becomes the distance. When the position O (s) equal to Lm (s) is reached, the optical path length 2 × Lm (s) of the measurement light is equal to the optical path length 2 × Lr (s) of the reference light. Therefore, the intensity of the synthesized light takes the maximum peak intensity at this position O (s).
　演算部２０は受光部１８からの合成光の強度が判定基準を超えるか否かを随時モニタし、反射点の位置が位置Ｏ（ｓ）に接近して判定基準を超えると、判定基準を満たす範囲内で最大の強度をとる反射点の位置、即ち最大ピーク強度をとる反射点の位置情報を位置情報取得部２４から取得して記録する。この記録された位置情報は位置Ｏ（ｓ）の位置情報に相当する。以上が記録ステップに相当する。 The arithmetic unit 20 monitors whether or not the intensity of the combined light from the light receiving unit 18 exceeds the criterion, and satisfies the criterion when the position of the reflection point approaches the position O (s) and exceeds the criterion. The position of the reflection point having the maximum intensity within the range, that is, the position information of the reflection point having the maximum peak intensity is acquired from the position information acquisition unit 24 and recorded. This recorded position information corresponds to the position information of the position O (s). The above corresponds to the recording step.
　次に、演算部２０は、基準点の位置情報（位置Ｏ（ｓ’）の位置情報）と記録ステップで得られた位置Ｏ（ｓ）の位置情報とから、基準点である出射口１６の出射点（シャッタ５の反射点Ｓ’に相当）から被測定物６の測定点Ｓまでの距離Ｌを算出する。距離Ｌの算出方法は、例えば、基準点の位置情報の値をＰＯｓ’、位置Ｏ（ｓ）の位置情報をＰＯｓとし、反射部１４が分割部１２から遠ざかるにつれ位置情報の値が増加する場合、
Ｌ＝Ｌｍ（ｓ）－Ｌｍ（ｓ’）＝Ｌｒ（ｓ）－Ｌｒ（ｓ’）＝ＰＯｓ－ＰＯｓ’
となる。以上が測定ステップに相当する。 Next, the calculation unit 20 uses the position information of the reference point (position information of the position O (s ′)) and the position information of the position O (s) obtained in the recording step to determine the emission port 16 that is the reference point. A distance L from the emission point (corresponding to the reflection point S ′ of the shutter 5) to the measurement point S of the DUT 6 is calculated. The calculation method of the distance L is, for example, when the position information value of the reference point is POs ′, the position information of the position O (s) is POs, and the position information value increases as the reflecting unit 14 moves away from the dividing unit 12. ,
L = Lm (s) −Lm (s ′) = Lr (s) −Lr (s ′) = POs−POs ′
It becomes. The above corresponds to the measurement step.
　尚、移動手段２２はモータ等の機械的なものであるから、移動手段２２の精度によっては反射点を各位置、特にピーク位置に完全に位置させることが困難な場合がある。このような場合、判定基準を超えた範囲の強度データをプロットし最大の強度となる反射点の位置を演算により算出するようにしても良い。このことは、後述の第２の測距方法、第３の測距方法でも同様である。 Since the moving means 22 is a mechanical device such as a motor, it may be difficult to completely position the reflection point at each position, particularly at the peak position, depending on the accuracy of the moving means 22. In such a case, the intensity data in a range exceeding the determination criterion may be plotted, and the position of the reflection point having the maximum intensity may be calculated by calculation. The same applies to a second distance measuring method and a third distance measuring method described later.
　また、基準点をシャッタ５の内面とせずに、図４（ａ）に示すように、被測定物６の第１測定点Ｓ１とし、第１測定点Ｓ１の位置情報取得後に図４（ｂ）に示すように、レーザ測距装置５０ａもしくは被測定物６を平行移動させて測定光を被測定物６の第２測定点Ｓ２で反射させるようにすれば、得られる距離Ｌは第１測定点Ｓ１と第２測定点Ｓ２の厚み方向の距離となる。尚、この場合、第１測定点Ｓ１と第２測定点Ｓ２の位置関係を予め把握しておき、レーザ測距装置５０ａに近い側（図４の例では第１測定点Ｓ１）を基準点とし、遠い側（図４の例では第２測定点Ｓ２）を測定点とすることが好ましい。また、移動手段２２の動作方向を参照光の光路長が減少する方向とする場合には、逆にレーザ測距装置５０ａから遠い側（図４の例では第２測定点Ｓ２）を基準点とし、近い側（図４の例では第１測定点Ｓ１）を測定点とすることが好ましい。 Further, as shown in FIG. 4A, the reference point is not the inner surface of the shutter 5, but is set as the first measurement point S1 of the object 6 to be measured, and after the position information of the first measurement point S1 is acquired, FIG. As shown in FIG. 4, if the laser distance measuring device 50a or the object to be measured 6 is translated to reflect the measurement light at the second measurement point S2 of the object to be measured 6, the obtained distance L is the first measurement point. This is the distance in the thickness direction between S1 and the second measurement point S2. In this case, the positional relationship between the first measurement point S1 and the second measurement point S2 is grasped in advance, and the side closer to the laser distance measuring device 50a (the first measurement point S1 in the example of FIG. 4) is used as a reference point. It is preferable that the far side (second measurement point S2 in the example of FIG. 4) be the measurement point. When the direction of movement of the moving means 22 is the direction in which the optical path length of the reference light decreases, the side far from the laser distance measuring device 50a (second measurement point S2 in the example of FIG. 4) is used as a reference point. It is preferable to use the near side (the first measurement point S1 in the example of FIG. 4) as the measurement point.
　次に、本発明に係る第２の形態のレーザ測距装置５０ｂを説明する。図５に示す本発明に係るレーザ測距装置５０ｂは、第１の形態のレーザ測距装置５０ａに加えて、測定光を第１測定光と第２測定光とに分割する測定光分割部２８を有している。そして、測定光分割部２８にて分割された第１レーザ光及び第２レーザ光の第１測定光は第１出射口１６ａから被測定物６の側に出射する。また、測定光分割部２８で分割された第１レーザ光及び第２レーザ光の第２測定光はミラー８で反射され第２出射口１６ｂから被測定物６の側に出射する。尚、第１測定光と第２測定光との装置内部における光路差（２×Ｌｄ）は、第１レーザ光及び第２レーザ光のいずれか長い方のコヒーレンス長よりも長い距離とする。よって、距離Ｌｄは第１レーザ光及び第２レーザ光のいずれか長い方のコヒーレンス長の１／２よりも長い距離となる。 Next, a laser range finder 50b according to a second embodiment of the present invention will be described. A laser distance measuring device 50b according to the present invention shown in FIG. 5 includes a measurement light dividing unit 28 for dividing the measurement light into a first measurement light and a second measurement light in addition to the laser distance measurement device 50a of the first embodiment. have. Then, the first measurement light of the first laser light and the second laser light divided by the measurement light dividing unit 28 is emitted from the first emission port 16a to the measured object 6 side. Further, the second measurement light of the first laser light and the second laser light divided by the measurement light dividing unit 28 is reflected by the mirror 8 and emitted from the second emission port 16b to the object to be measured 6 side. Note that the optical path difference (2 × Ld) in the apparatus between the first measurement light and the second measurement light is longer than the longer coherence length of the first laser light and the second laser light. Therefore, the distance Ld is a distance longer than ½ of the longer coherence length of the first laser beam and the second laser beam.
　また、本発明に係る第２の測距方法及び後述の第３の測距方法では、レーザ照射手段の選定を、第１測定光、第２測定光のうち一方を遮蔽した状態で行う。また、この第２の測距方法及び第３の測距方法での最大ピーク強度は一方の測定光が干渉しない状態のものとする。即ち、第２の測距方法及び第３の測距方法での最大ピーク強度は、第１レーザ光の第１測定光（第２測定光）による干渉光の（図２中の位置Ｏにおける）強度ピークと、第２レーザ光の第１測定光（第２測定光）による干渉光の（図２中の位置Ｏにおける）強度ピークと、後述するように光路差がコヒーレンス長を超えて一定強度となる第１レーザ光及び第２レーザ光の第２測定光（第１測定光）の強度とが合わさったものとなる。そして、この最大ピーク強度とレーザ照射手段の出力変動範囲とに応じて判定基準の値が設定される。 In the second distance measuring method according to the present invention and the third distance measuring method described later, the laser irradiation means is selected in a state where one of the first measurement light and the second measurement light is shielded. Further, the maximum peak intensity in the second distance measuring method and the third distance measuring method is set so that one measurement light does not interfere. That is, the maximum peak intensity in the second distance measurement method and the third distance measurement method is the interference light (at the position O in FIG. 2) of the first laser beam by the first measurement light (second measurement light). The intensity peak, the intensity peak of interference light (at position O in FIG. 2) due to the first measurement light (second measurement light) of the second laser light, and the optical path difference exceeds the coherence length and is constant intensity as will be described later. And the intensity of the second measurement light (first measurement light) of the first laser light and the second laser light. Then, a criterion value is set according to the maximum peak intensity and the output fluctuation range of the laser irradiation means.
　次に、本発明に係る第２の測距方法をレーザ測距装置５０ｂの動作とともに説明する。尚、レーザ照射手段を３つ有する図７（ａ）に示すレーザ測距装置５１ｂも基本動作は全く同じである。 Next, the second distance measuring method according to the present invention will be described together with the operation of the laser distance measuring device 50b. The basic operation of the laser distance measuring device 51b shown in FIG. 7A having three laser irradiation means is exactly the same.
　本発明に係るレーザ測距装置５０ｂでは、予め第１測定光と第２測定光との装置内部における光路差の１／２の値である距離Ｌｄを取得する必要がある。レーザ測距装置５０ｂに好適な距離Ｌｄの取得方法は後述する。尚、距離Ｌｄの取得は測定毎に行う必要は無く、レーザ測距装置５０ｂの出荷時等に行ってメモリ等に記録しておいても良い。 In the laser distance measuring device 50b according to the present invention, it is necessary to obtain a distance Ld that is a value of ½ of the optical path difference between the first measurement light and the second measurement light in the device in advance. A method for obtaining the distance Ld suitable for the laser distance measuring device 50b will be described later. The distance Ld need not be obtained every measurement, and may be recorded at the time of shipment of the laser distance measuring device 50b and recorded in a memory or the like.
　本発明に係る第２の測距方法では、先ず、図５（ａ）に示すように、被測定物６をその第１測定点Ｓ１に第１測定光が、第２測定点Ｓ２に第２測定光が垂直に照射するように設置する。次に、反射部１４の反射点を起点位置に位置させる。ここでの起点位置は分割点から第１出射口１６ａまでの距離と等しい反射点の位置とすることが好ましい。 In the second distance measuring method according to the present invention, first, as shown in FIG. 5 (a), the first measuring light is measured at the first measuring point S1 of the device under test 6 and the second measured at the second measuring point S2. Install so that the measurement light is irradiated vertically. Next, the reflection point of the reflection unit 14 is positioned at the starting position. The starting position here is preferably a position of a reflection point equal to the distance from the dividing point to the first exit port 16a.
　次に、第１レーザ照射手段１０ａ、第２レーザ照射手段１０ｂを動作させ第１レーザ光及び第２レーザ光を同時に照射する。これにより、第１レーザ光及び第２レーザ光の参照光は反射点で反射され受光部１８に到達する。また、測定光分割部２８で分割された第１レーザ光及び第２レーザ光の第１測定光は第１出射口１６ａから出射した後、被測定物６の第１測定点Ｓ１で反射され、測定光分割部２８、分割点を経由して受光部１８に到達する。また、第１レーザ光及び第２レーザ光の第２測定光は第２出射口１６ｂから出射した後、被測定物６の第２測定点Ｓ２で反射され、ミラー８、測定光分割部２８、分割点を経由して受光部１８に到達する。受光部１８は、第１レーザ光及び第２レーザ光の参照光と、第１レーザ光及び第２レーザ光の第１測定光と、第１レーザ光及び第２レーザ光の第２測定光とを受光し、それらの光が全て合成された合成光の強度データを演算部２０に出力する。そして、この状態を維持しながら位置情報取得部２４が移動手段２２を動作させ反射点を反射部１４ごと参照光の光路長が増加する方向に移動させる。 Next, the first laser irradiation unit 10a and the second laser irradiation unit 10b are operated to irradiate the first laser beam and the second laser beam simultaneously. Thereby, the reference light of the first laser light and the second laser light is reflected at the reflection point and reaches the light receiving unit 18. Further, the first measurement light of the first laser light and the second laser light divided by the measurement light dividing unit 28 is emitted from the first emission port 16a, and then reflected by the first measurement point S1 of the object 6 to be measured. The light reaches the light receiving unit 18 via the measurement light dividing unit 28 and the dividing point. Further, the second measurement light of the first laser light and the second laser light is emitted from the second emission port 16b and then reflected by the second measurement point S2 of the object 6 to be measured, and the mirror 8, the measurement light dividing unit 28, It reaches the light receiving unit 18 via the dividing point. The light-receiving unit 18 includes a reference beam for the first laser beam and the second laser beam, a first measurement beam for the first laser beam and the second laser beam, and a second measurement beam for the first laser beam and the second laser beam. , And outputs the intensity data of the combined light in which all the lights are combined to the arithmetic unit 20. Then, while maintaining this state, the position information acquisition unit 24 operates the moving unit 22 to move the reflection point in the direction in which the optical path length of the reference light increases together with the reflection unit 14.
　反射点が移動して分割点から反射点までの距離が分割点から第１測定点Ｓ１までの距離と等しい位置Ｏ（ｓ１）に到達すると、第１測定光の光路長と参照光の光路長とが等しくなる。また、距離Ｌｄは第１レーザ光及び第２レーザ光のコヒーレンス長よりも長いから、この位置Ｏ（ｓ１）近傍では第２測定光と参照光との光路差はコヒーレンス長を超え、第２測定光が参照光及び第１測定光と干渉することはない。従って、第２測定光は一定強度の光として受光部１８に受光され、第２測定光が第１位置情報の取得に悪影響を及ぼすことはない。そして、第２の測距方法での最大ピーク強度は一方の測定光が干渉しない状態のものとしているから、よって、この位置Ｏ（ｓ１）において合成光の強度は最大ピーク強度と略同等となる。 When the reflection point moves and the distance from the division point to the reflection point reaches a position O (s1) equal to the distance from the division point to the first measurement point S1, the optical path length of the first measurement light and the optical path length of the reference light And become equal. Further, since the distance Ld is longer than the coherence length of the first laser light and the second laser light, the optical path difference between the second measurement light and the reference light exceeds the coherence length near the position O (s1), and the second measurement is performed. The light does not interfere with the reference light and the first measurement light. Therefore, the second measurement light is received by the light receiving unit 18 as light having a constant intensity, and the second measurement light does not adversely affect the acquisition of the first position information. Since the maximum peak intensity in the second distance measuring method is such that one of the measurement lights does not interfere, the intensity of the synthesized light at this position O (s1) is substantially equal to the maximum peak intensity. .
　演算部２０は受光部１８からの合成光の強度が判定基準を超えるか否かを随時モニタし、判定基準を超えた場合、判定基準を満たす範囲内で最大の強度をとる反射点の第１位置（＝位置Ｏ（ｓ１））の位置情報を位置情報取得部２４から取得して第１位置情報として記録する。 The calculation unit 20 monitors whether or not the intensity of the combined light from the light receiving unit 18 exceeds the determination criterion, and when it exceeds the determination criterion, the first reflection point having the maximum intensity within the range satisfying the determination criterion. The position information of the position (= position O (s1)) is acquired from the position information acquisition unit 24 and recorded as the first position information.
　次に、反射点がさらに移動して分割点から反射点までの距離が分割点→測定光分割部２８→ミラー８→第２測定点Ｓ２までの距離と等しい位置Ｏ（ｓ２）に到達すると、第２測定光の光路長と参照光の光路長とが等しくなる。そして、この位置Ｏ（ｓ２）において合成光の強度は同様に最大ピーク強度と略同等となる。 Next, when the reflection point further moves and the distance from the division point to the reflection point reaches a position O (s2) equal to the distance from the division point → the measurement light dividing unit 28 → the mirror 8 → the second measurement point S2, The optical path length of the second measurement light is equal to the optical path length of the reference light. Then, at this position O (s2), the intensity of the synthesized light is similarly substantially equal to the maximum peak intensity.
　演算部２０は受光部１８からの合成光の強度が判定基準を超えるか否かを随時モニタし、判定基準を超えた場合、判定基準を満たす範囲内で最大の強度をとる反射点の第２位置（＝位置Ｏ（ｓ２））の位置情報を位置情報取得部２４から取得して第２位置情報として記録する。以上が第２の測距方法の記録ステップに相当する。尚、前述のように距離Ｌｄは第１レーザ光及び第２レーザ光のコヒーレンス長よりも長いから、この位置Ｏ（ｓ２）近傍では第１測定光と参照光との光路差はコヒーレンス長を超え、第１測定光が参照光及び第２測定光と干渉することはない。従って、第１測定光が第２位置情報の取得に悪影響を及ぼすことはない。 The calculation unit 20 monitors whether or not the intensity of the combined light from the light receiving unit 18 exceeds the determination criterion, and when it exceeds the determination criterion, the second reflection point having the maximum intensity within the range satisfying the determination criterion. The position information of the position (= position O (s2)) is acquired from the position information acquisition unit 24 and recorded as second position information. The above corresponds to the recording step of the second distance measuring method. Since the distance Ld is longer than the coherence length of the first laser light and the second laser light as described above, the optical path difference between the first measurement light and the reference light exceeds the coherence length in the vicinity of the position O (s2). The first measurement light does not interfere with the reference light and the second measurement light. Therefore, the first measurement light does not adversely affect the acquisition of the second position information.
　次に、演算部２０は、第１位置情報と第２位置情報と予め取得されている距離Ｌｄの値とから、被測定物６の第１測定点Ｓ１と第２測定点Ｓ２との間の厚み方向の距離Ｌを算出する。距離Ｌの算出方法は、例えば、第１位置情報の値をＰｓ１、第２位置情報をＰｓ２とし、反射部１４が分割部１２から遠ざかるにつれ位置情報の値が増加する場合、
Ｌ＝Ｐｓ２－Ｐｓ１－Ｌｄ
となる。以上が第２の測距方法の測定ステップに相当する。 Next, the calculation unit 20 determines between the first measurement point S1 and the second measurement point S2 of the DUT 6 from the first position information, the second position information, and the value of the distance Ld acquired in advance. A distance L in the thickness direction is calculated. The calculation method of the distance L is, for example, when the value of the first position information is Ps1, the second position information is Ps2, and the value of the position information increases as the reflecting unit 14 moves away from the dividing unit 12.
L = Ps2-Ps1-Ld
It becomes. The above corresponds to the measurement step of the second distance measuring method.
　次に、第１測定光と第２測定光との装置内部における距離Ｌｄを取得する方法を説明する。尚、以下に示す距離Ｌｄの取得方法は、基本的に本発明に係る第２の測距方法及びレーザ測距装置５０ｂの動作と同等である。また、以下に示す距離Ｌｄの取得方法は本発明に係るレーザ測距装置５０ｂに好適なものであるが、必ずしもこの方法を用いる必要は無い。 Next, a method for obtaining the distance Ld inside the apparatus between the first measurement light and the second measurement light will be described. The distance Ld acquisition method described below is basically the same as the operation of the second distance measuring method and the laser distance measuring device 50b according to the present invention. Further, the method for obtaining the distance Ld shown below is suitable for the laser distance measuring device 50b according to the present invention, but this method is not necessarily used.
　先ず、図５（ｂ）に示すように、表面が平滑な平板５を、その第１測定点Ｓ１’に第１測定光が、第２測定点Ｓ２’に第２測定光が垂直に照射するように設置する。このとき、第１出射口１６ａから第１測定点Ｓ１’までの距離と、第２出射口１６ｂから第２測定点Ｓ２’までの距離とを等しくする。次に、反射部１４の反射点を起点位置よりも参照光の光路長が若干短くなる位置に位置させる。 First, as shown in FIG. 5B, the flat plate 5 having a smooth surface is irradiated with the first measurement light perpendicularly to the first measurement point S1 ′ and the second measurement light perpendicularly to the second measurement point S2 ′. Install as follows. At this time, the distance from the first exit 16a to the first measurement point S1 'is made equal to the distance from the second exit 16b to the second measurement point S2'. Next, the reflection point of the reflection unit 14 is positioned at a position where the optical path length of the reference light is slightly shorter than the starting position.
　そして、上記の記録ステップを行い、分割点から平板５の第１測定点Ｓ１’までの距離と分割点から反射点までの距離とが等しくなる反射点の第１位置Ｏ（ｓ１’）の第１位置情報と、分割点→測定光分割部２８→ミラー８→第２測定点Ｓ２’までの距離と分割点から反射点までの距離とが等しくなる反射点の第２位置Ｏ（ｓ２’）の第２位置情報と、を記録する。 Then, the above recording step is performed, and the first position O (s1 ′) of the reflection point at which the distance from the division point to the first measurement point S1 ′ of the flat plate 5 is equal to the distance from the division point to the reflection point. The second position O (s2 ′) of the reflection point where the one-position information and the distance from the dividing point → the measuring light dividing unit 28 → the mirror 8 → the second measuring point S2 ′ are equal to the distance from the dividing point to the reflecting point. The second position information is recorded.
　次に、演算部２０は、得られた第１位置情報と第２位置情報とから、距離Ｌｄを算出する。距離Ｌｄの算出方法は、例えば、第１位置情報の値をＰｓ１’、第２位置情報をＰｓ２’とし、反射部１４が分割部１２から遠ざかるにつれ位置情報の値が増加する場合、
Ｌｄ＝Ｐｓ２’－Ｐｓ１’
となる。 Next, the computing unit 20 calculates the distance Ld from the obtained first position information and second position information. The calculation method of the distance Ld is, for example, when the value of the first position information is Ps1 ′, the second position information is Ps2 ′, and the value of the position information increases as the reflecting unit 14 moves away from the dividing unit 12.
Ld = Ps2′−Ps1 ′
It becomes.
　次に、図６に本発明に係る第３の形態のレーザ測距装置５０ｃを示す。第３の形態のレーザ測距装置５０ｃは被測定物６の一面側に位置する第１測定点Ｓ１と、第１測定点Ｓ１の裏面に位置する第２測定点Ｓ２との間の厚み方向の距離を測距することで、被測定物６の厚みｔを測距するものである。従って、その構成は第１測定光と第２測定光との光学経路が異なる以外、第２の形態のレーザ測距装置５０ｂと基本的に同等である。 Next, FIG. 6 shows a laser distance measuring device 50c according to a third embodiment of the present invention. The laser range finder 50c according to the third embodiment has a thickness direction between a first measurement point S1 located on one surface side of the object 6 to be measured and a second measurement point S2 located on the back surface of the first measurement point S1. By measuring the distance, the thickness t of the DUT 6 is measured. Therefore, the configuration is basically the same as that of the laser distance measuring device 50b of the second embodiment except that the optical paths of the first measurement light and the second measurement light are different.
　そして、レーザ測距装置５０ｃにおいては、測定光分割部２８にて分割された第１測定光は、ミラー８ａ、ミラー８ｂ、ミラー８ｃで反射され第１出射口１６ａから第２出射口１６ｂに向けて出射する。また、測定光分割部２８で分割された第２測定光はミラー８ｄ、ミラー８ｅで反射され第２出射口１６ｂから第１出射口１６ａに向けて出射する。尚、第１出射口１６ａと第２出射口１６ｂとは対向する位置に設けられ、被測定物６はこの第１出射口１６ａと第２出射口１６ｂとの間に配置される。そして、図６（ａ）に示すように、第１出射口１６ａと第２出射口１６ｂとの間に何も存在しない無測定物状態の場合には、第１出射口１６ａから出射した第１測定光は、第２出射口１６ｂから再度レーザ測距装置５０ｃ内に入射してミラー８ｅ、ミラー８ｄで反射され測定光分割部２８に帰還する。また、第２出射口１６ｂから出射した第２測定光は第１出射口１６ａから再度レーザ測距装置５０ｃ内に入射してミラー８ｃ、ミラー８ｂ、ミラー８ａで反射され測定光分割部２８に帰還する。よって、無測定物状態においては第１測定光と第２測定光とは同じ光路を互いに逆方向に進んで測定光分割部２８に帰還することとなる。従って、このときの第１測定光と第２測定光との光路長は等しくなる。尚、測定光分割部２８から第１出射口１６ａまでの第１測定光の光路長と測定光分割部２８から第２出射口１６ｂまでの第２測定光の光路長とは完全に等しくする必要は無いが、略同等として無測定物状態における第１測定光及び第２測定光の測定光分割部２８から測定光分割部２８に帰還するまでの光路（即ち、第１測定光における測定光分割部２８→ミラー８ａ→ミラー８ｂ→ミラー８ｃ→ミラー８ｅ→ミラー８ｄ→測定光分割部２８までの光路）の中間地点Ｐ０を、第１出射口１６ａと第２出射口１６ｂとの間の中間位置近傍とすることが好ましい。 In the laser distance measuring device 50c, the first measurement light divided by the measurement light dividing unit 28 is reflected by the mirror 8a, the mirror 8b, and the mirror 8c and is directed from the first emission port 16a to the second emission port 16b. And exit. The second measurement light split by the measurement light splitting unit 28 is reflected by the mirror 8d and the mirror 8e, and exits from the second exit 16b toward the first exit 16a. In addition, the 1st output port 16a and the 2nd output port 16b are provided in the position which opposes, and the to-be-measured object 6 is arrange | positioned between this 1st output port 16a and the 2nd output port 16b. Then, as shown in FIG. 6A, in the case of an unmeasured object state in which nothing exists between the first emission port 16a and the second emission port 16b, the first emitted from the first emission port 16a. The measurement light again enters the laser distance measuring device 50c from the second exit 16b, is reflected by the mirror 8e and the mirror 8d, and returns to the measurement light splitting unit 28. The second measurement light emitted from the second emission port 16b is incident on the laser distance measuring device 50c again from the first emission port 16a, reflected by the mirror 8c, the mirror 8b, and the mirror 8a, and returned to the measurement light dividing unit 28. To do. Therefore, in the non-measurement state, the first measurement light and the second measurement light travel on the same optical path in opposite directions and return to the measurement light splitting unit 28. Accordingly, the optical path lengths of the first measurement light and the second measurement light at this time are equal. It should be noted that the optical path length of the first measurement light from the measurement light dividing unit 28 to the first emission port 16a and the optical path length of the second measurement light from the measurement light division unit 28 to the second emission port 16b need to be completely equal. Although there is no equivalent, the optical path of the first measurement light and the second measurement light in the unmeasured object state from the measurement light splitting unit 28 to the measurement light splitting unit 28 (ie, the measurement light splitting in the first measurement light) The intermediate point P0 between the first exit port 16a and the second exit port 16b is an intermediate point P0 of the section 28 → mirror 8a → mirror 8b → mirror 8c → mirror 8e → mirror 8d → light path to the measurement light splitting section 28) It is preferable to be in the vicinity.
　次に、本発明に係る第３の測距方法をレーザ測距装置５０ｃの動作とともに説明する。尚、レーザ照射手段を３つ有する図７（ｂ）に示すレーザ測距装置５１ｃも基本動作は全く同じである。 Next, a third distance measuring method according to the present invention will be described together with the operation of the laser distance measuring device 50c. The basic operation of the laser distance measuring device 51c shown in FIG. 7B having three laser irradiation means is exactly the same.
　本発明に係る第３の測距方法では、先ず、第１測定光及び第２測定光の光路長と参照光の光路長とが等しくなる反射点の位置（原点位置Ｏ）を取得して原点位置情報として記録する原点取得ステップを行う。尚、原点位置情報の取得は以下のようにして行うことが好ましい。 In the third distance measuring method according to the present invention, first, the position of the reflection point (origin position O) where the optical path lengths of the first measurement light and the second measurement light are equal to the optical path length of the reference light is obtained to obtain the origin. An origin acquisition step of recording as position information is performed. The origin position information is preferably acquired as follows.
　先ず、無測定物状態で反射部１４の反射点を起点位置に位置させる。ここでの起点位置は分割点から中間地点Ｐ０までの測定光の光学経路よりも若干長くなるような反射点の位置とすることが好ましい。 First, the reflecting point of the reflecting portion 14 is positioned at the starting position in the state of no measurement object. The starting position here is preferably a position of a reflection point that is slightly longer than the optical path of the measuring light from the dividing point to the intermediate point P0.
　次に、この状態で第１レーザ照射手段１０ａ、第２レーザ照射手段１０ｂを動作させ第１レーザ光及び第２レーザ光を同時に照射する。これにより、参照光は分割点→反射点→分割点→受光部１８の光路をとって受光部１８に到達する。また、第１測定光は分割点→測定光分割部２８→ミラー８ａ→ミラー８ｂ→ミラー８ｃ→第１出射口１６ａ→第２出射口１６ｂ→ミラー８ｅ→ミラー８ｄ→測定光分割部２８→分割点→受光部１８の光路をとって受光部１８に到達する。また、第２測定光は分割点→測定光分割部２８→ミラー８ｄ→ミラー８ｅ→第２出射口１６ｂ→第１出射口１６ａ→ミラー８ｃ→ミラー８ｂ→ミラー８ａ→測定光分割部２８→分割点→受光部１８の光路をとって受光部１８に到達する。 Next, in this state, the first laser irradiation unit 10a and the second laser irradiation unit 10b are operated to simultaneously irradiate the first laser beam and the second laser beam. As a result, the reference light reaches the light receiving unit 18 along the optical path of the dividing point → the reflection point → the dividing point → the light receiving unit 18. Further, the first measurement light is divided at the division point → measurement light division unit 28 → mirror 8a → mirror 8b → mirror 8c → first emission port 16a → second emission port 16b → mirror 8e → mirror 8d → measurement beam division unit 28 → division. The light path from the point to the light receiving unit 18 is reached and reaches the light receiving unit 18. Further, the second measurement light is divided at the division point → measurement light division unit 28 → mirror 8d → mirror 8e → second emission port 16b → first emission port 16a → mirror 8c → mirror 8b → mirror 8a → measurement light division unit 28 → division. The light path from the point to the light receiving unit 18 is reached and reaches the light receiving unit 18.
　そして、この状態を維持しながら位置情報取得部２４が移動手段２２を動作させ反射点を反射部１４ごと参照光の光路長が減少する方向に移動させる。 Then, while maintaining this state, the position information acquisition unit 24 operates the moving unit 22 to move the reflection point in the direction in which the optical path length of the reference light decreases together with the reflection unit 14.
　反射点が移動して参照光の光路長と第１測定光及び第２測定光の光路長とが等しくなる原点位置Ｏに到達すると、この原点位置Ｏでは第１レーザ光の参照光と第１レーザ光の第１測定光及び第２測定光とによる干渉光と、第２レーザ光の参照光と第２レーザ光の第１測定光及び第２測定光とによる干渉光とが全て明部のピークを取る。ここで、第３の測距方法での最大ピーク強度は一方の測定光が干渉しない状態のものとしているから、この原点位置Ｏにおける合成光の強度は最大ピーク強度の約２倍のピーク強度をとる。従って、原点位置情報の取得時の判定基準もこれに応じて大きくなる。 When the reflection point moves and reaches the origin position O where the optical path length of the reference light and the optical path lengths of the first measurement light and the second measurement light become equal, the reference light of the first laser light and the first light are transmitted at the origin position O. The interference light caused by the first measurement light and the second measurement light of the laser light and the interference light caused by the reference light of the second laser light and the first measurement light and the second measurement light of the second laser light are all in the bright part. Take a peak. Here, since the maximum peak intensity in the third distance measuring method is that in which one of the measurement lights does not interfere, the intensity of the combined light at the origin position O is about twice the maximum peak intensity. Take. Therefore, the criterion for obtaining the origin position information is increased accordingly.
　演算部２０は受光部１８からの合成光の強度が原点位置情報の取得時の判定基準を超えるか否かを随時モニタし、原点位置情報の取得時の判定基準を超えた場合、判定基準を満たす範囲内で最大の強度をとる反射点の位置（＝原点位置Ｏ）の位置情報を位置情報取得部２４から取得して原点位置情報として記録する。以上が、原点取得ステップに相当する。尚、参照光の光路上の原点位置Ｏは、図６中の測定光の光路上では中間地点Ｐ０と対応する。 The computing unit 20 monitors whether or not the intensity of the combined light from the light receiving unit 18 exceeds a determination criterion at the time of acquiring the origin position information. Position information of the position of the reflection point (= origin position O) having the maximum intensity within the range to be satisfied is acquired from the position information acquisition unit 24 and recorded as origin position information. The above corresponds to the origin acquisition step. The origin position O on the optical path of the reference light corresponds to the intermediate point P0 on the optical path of the measurement light in FIG.
　上記の原点位置情報の取得方法は最も高精度であり本発明に係るレーザ測距装置５０ｃに好適なものであるが、必ずしもこの方法を用いる必要は無い。尚、原点位置情報の取得は測定毎に行うことが好ましいが、さほど高精度の測定値を必要としない場合にはこの限りではない。 The origin position information acquisition method described above has the highest accuracy and is suitable for the laser distance measuring device 50c according to the present invention, but it is not always necessary to use this method. The acquisition of the origin position information is preferably performed for each measurement. However, this is not the case when a highly accurate measurement value is not required.
　次に、図６（ｂ）に示すように被測定物６を第１出射口１６ａと第２出射口１６ｂとの間に配置する。このとき、被測定物６を中間地点Ｐ０と重なり、且つ中間地点Ｐ０から第１測定点Ｓ１までの距離Ｌ１と中間地点Ｐ０から第２測定点Ｓ２までの距離Ｌ２との差が第１レーザ光及び第２レーザ光のいずれか長い方のコヒーレンス長の１／２の値よりも長い距離となるように配置することが好ましい。 Next, as shown in FIG. 6B, the DUT 6 is disposed between the first exit port 16a and the second exit port 16b. At this time, the measured object 6 overlaps the intermediate point P0, and the difference between the distance L1 from the intermediate point P0 to the first measurement point S1 and the distance L2 from the intermediate point P0 to the second measurement point S2 is the first laser beam. It is preferable that the distance is longer than the half of the longer coherence length of the second laser beam.
　ここで、被測定物６を中間地点Ｐ０と重ならないように配置すると、測定時の第１測定光の光路長もしくは第２測定光の光路長のいずれか一方が原点位置における参照光の光路長より長くなり他方が短くなる。このような場合、本願の測距方法においては移動手段２２を測定中に逆動作させて参照光の光路長を増加させる方向と減少させる方向とに移動させる必要が生じる。移動手段２２であるモータ等の機械は、一定方向に動作させる場合においては位置情報と実際の位置とに大きな差は生じないが、逆動作させるとバックラッシュが発生し位置情報と実際の位置とに誤差が生じる。被測定物６を中間地点Ｐ０と重なるように配置すれば、測定時の第１測定光の光路長と第２測定光の光路長とはいずれも原点位置における参照光の光路長より短くなり、反射部１４は原点位置から参照光の光路長を減少させる方向のみに移動すればよく、移動手段２２が逆動作する必要は無い。よって、高精度の厚み測定を行うことができる。 Here, if the DUT 6 is arranged so as not to overlap the intermediate point P0, either the optical path length of the first measurement light or the optical path length of the second measurement light at the time of measurement is the optical path length of the reference light at the origin position. Longer and the other shorter. In such a case, in the distance measuring method of the present application, it is necessary to reversely move the moving means 22 during measurement to move the reference light in the direction of increasing or decreasing the optical path length of the reference light. When the machine such as a motor that is the moving means 22 is operated in a certain direction, there is no great difference between the position information and the actual position. An error occurs. If the DUT 6 is arranged so as to overlap the intermediate point P0, the optical path length of the first measurement light and the optical path length of the second measurement light at the time of measurement are both shorter than the optical path length of the reference light at the origin position, The reflection unit 14 only needs to move from the origin position in the direction of decreasing the optical path length of the reference light, and the moving unit 22 does not need to operate in reverse. Therefore, highly accurate thickness measurement can be performed.
　また、距離Ｌ１と距離Ｌ２との差をコヒーレンス長の１／２よりも長い距離になるように配置すれば、後述の第１測定光による第１測定点Ｓ１の測定時には第２測定光は干渉せず、第２測定光による第２測定点Ｓ２の測定時には第１測定光は干渉することがない。従って、レーザ測距装置５０ｃによる被測定物６の厚みｔの測距を効率良く行うことができる。尚、被測定物６の厚みｔがコヒーレンス長の１／２よりも薄く上記の条件を満たすことができない場合、被測定物６を中間地点Ｐ０からずらして第１測定光と第２測定光との光路差をコヒーレンス長の値以上とする。この場合、移動手段２２は逆動作が必要でバックラッシュに伴う誤差が生じるが、移動手段２２に高精度のアクチュエータを用いればバックラッシュを含む繰り返し位置精度は約２０ｎｍ程度であり、要求される測定精度によっては十分に使用可能である。 Further, if the difference between the distance L1 and the distance L2 is set to be a distance longer than ½ of the coherence length, the second measurement light interferes when measuring the first measurement point S1 by the first measurement light described later. In addition, the first measurement light does not interfere when measuring the second measurement point S2 by the second measurement light. Accordingly, the distance measurement of the thickness t of the DUT 6 by the laser distance measuring device 50c can be efficiently performed. If the thickness t of the device under test 6 is smaller than ½ of the coherence length and the above condition cannot be satisfied, the device under test 6 is shifted from the intermediate point P0, and the first measurement light and the second measurement light Is equal to or greater than the coherence length. In this case, the moving means 22 requires reverse operation and an error due to backlash occurs. However, if a highly accurate actuator is used for the moving means 22, the repeat position accuracy including backlash is about 20 nm, and the required measurement is performed. Depending on the accuracy, it can be used sufficiently.
　尚、レーザ測距装置５０ｃは測定光の光学経路を図８に示すようにして、第１測定光と第２測定光の装置内部における光路差を第１レーザ光及び第２レーザ光のいずれか長い方のコヒーレンス長よりも長い距離としても良い。この構成によれば、装置内部における第１測定光と第２測定光との光路差が既にコヒーレンス長よりも長く設定されているから、被測定物６の設置位置によらず被測定物６の厚みｔの測距を行うことができる。ただしこの場合、移動手段２２の逆動作が必要となる。 The laser distance measuring device 50c sets the optical path of the measurement light as shown in FIG. 8, and the optical path difference between the first measurement light and the second measurement light inside the device is either the first laser light or the second laser light. The distance may be longer than the longer coherence length. According to this configuration, since the optical path difference between the first measurement light and the second measurement light inside the apparatus is already set longer than the coherence length, the measurement object 6 can be measured regardless of the installation position of the measurement object 6. Distance measurement of the thickness t can be performed. However, in this case, the reverse operation of the moving means 22 is required.
　次に、第１レーザ照射手段１０ａ、第２レーザ照射手段１０ｂを動作させ第１レーザ光及び第２レーザ光を同時に照射する。これにより、第１レーザ光及び第２レーザ光の参照光は反射点で反射され受光部１８に到達する。また、測定光分割部２８で分割された第１レーザ光及び第２レーザ光の第１測定光は第１出射口１６ａから出射した後、被測定物６の第１測定点Ｓ１で反射され、ミラー８ｃ、ミラー８ｂ、ミラー８ａ、測定光分割部２８、分割点を経由して受光部１８に到達する。また、第１レーザ光及び第２レーザ光の第２測定光は第２出射口１６ｂから出射した後、被測定物６の第２測定点Ｓ２で反射され、ミラー８ｅ、ミラー８ｄ、測定光分割部２８、分割点を経由して受光部１８に到達する。受光部１８は、第１レーザ光及び第２レーザ光の参照光と、第１レーザ光及び第２レーザ光の第１測定光と、第１レーザ光及び第２レーザ光の第２測定光とを受光し、それらの光が全て合成された合成光の強度を演算部２０に出力する。 Next, the first laser irradiation unit 10a and the second laser irradiation unit 10b are operated to irradiate the first laser beam and the second laser beam simultaneously. Thereby, the reference light of the first laser light and the second laser light is reflected at the reflection point and reaches the light receiving unit 18. Further, the first measurement light of the first laser light and the second laser light divided by the measurement light dividing unit 28 is emitted from the first emission port 16a, and then reflected by the first measurement point S1 of the object 6 to be measured. The light reaches the light receiving unit 18 via the mirror 8c, the mirror 8b, the mirror 8a, the measuring light dividing unit 28, and the dividing point. Further, the second measurement light of the first laser light and the second laser light is emitted from the second emission port 16b and then reflected at the second measurement point S2 of the object 6 to be measured, and the mirror 8e, the mirror 8d, and the measurement light division. The light reaches the light receiving part 18 via the part 28 and the dividing point. The light-receiving unit 18 includes a reference beam for the first laser beam and the second laser beam, a first measurement beam for the first laser beam and the second laser beam, and a second measurement beam for the first laser beam and the second laser beam. And outputs the intensity of the combined light, which is a combination of all the lights, to the arithmetic unit 20.
　そして、この状態を維持しながら位置情報取得部２４が移動手段２２を動作させ反射点を反射部１４ごと参照光の光路長が減少する方向に移動させる。 Then, while maintaining this state, the position information acquisition unit 24 operates the moving unit 22 to move the reflection point in the direction in which the optical path length of the reference light decreases together with the reflection unit 14.
　反射点が移動して分割点から反射点までの距離が分割点から第１測定点Ｓ１までの第１測定光の片道分の光路長と等しい位置Ｏ（ｓ１）に到達すると、第１測定光の光路長と参照光の光路長とが等しくなる。そして、この位置Ｏ（ｓ１）では第１測定光の第１レーザ光による干渉光と第１測定光の第２レーザ光による干渉光とが明部のピークを取り、この位置Ｏ（ｓ１）において合成光の強度は最大ピーク強度と略同等となる。 When the reflection point moves and reaches the position O (s1) where the distance from the division point to the reflection point is equal to the optical path length of one way of the first measurement light from the division point to the first measurement point S1, the first measurement light is reached. Is equal to the optical path length of the reference light. At this position O (s1), the interference light from the first laser light of the first measurement light and the interference light from the second laser light of the first measurement light have a bright peak, and at this position O (s1). The intensity of the synthesized light is substantially equal to the maximum peak intensity.
　演算部２０は受光部１８からの合成光の強度が判定基準を超えるか否かを随時モニタし、判定基準を超えた場合、判定基準を満たす範囲内で最大の強度をとる反射点の第１位置（＝位置Ｏ（ｓ１））の位置情報を位置情報取得部２４から取得して第１位置情報として記録する。尚、原点位置Ｏから位置Ｏ（ｓ１）までの距離は距離Ｌ１に相当する。このとき、被測定物６を中間地点Ｐ０から所定量ずらして配置することにより、第１測定光と第２測定光との光路差は第１レーザ光及び第２レーザ光のコヒーレンス長よりも長くなり、よって、この位置Ｏ（ｓ１）近傍では第２測定光は干渉せず第２測定光が第１位置情報の取得に悪影響を及ぼすことはない。 The calculation unit 20 monitors whether or not the intensity of the combined light from the light receiving unit 18 exceeds the determination criterion, and when it exceeds the determination criterion, the first reflection point having the maximum intensity within the range satisfying the determination criterion. The position information of the position (= position O (s1)) is acquired from the position information acquisition unit 24 and recorded as the first position information. The distance from the origin position O to the position O (s1) corresponds to the distance L1. At this time, by arranging the DUT 6 to be shifted from the intermediate point P0 by a predetermined amount, the optical path difference between the first measurement light and the second measurement light is longer than the coherence length of the first laser light and the second laser light. Therefore, the second measurement light does not interfere in the vicinity of the position O (s1), and the second measurement light does not adversely affect the acquisition of the first position information.
　次に、反射点がさらに移動して分割点から反射点までの距離が分割点から第２測定点Ｓ２までの第２測定光の片道分の光路長と等しい位置Ｏ（ｓ２）に到達すると、第２測定光の光路長と参照光の光路長とが等しくなる。この位置Ｏ（ｓ２）では第２測定光の第１レーザ光による干渉光と第２測定光の第２レーザ光による干渉光とが明部のピークを取り、この位置Ｏ（ｓ２）において合成光の強度は最大ピーク強度と略同等となる。 Next, when the reflection point further moves and reaches a position O (s2) where the distance from the division point to the reflection point is equal to the optical path length of one way of the second measurement light from the division point to the second measurement point S2, The optical path length of the second measurement light is equal to the optical path length of the reference light. At this position O (s2), the interference light by the first laser light of the second measurement light and the interference light by the second laser light of the second measurement light have a bright peak, and the combined light at this position O (s2). The intensity of is substantially equal to the maximum peak intensity.
　演算部２０は受光部１８からの合成光の強度が判定基準を超えるか否かを随時モニタし、判定基準を超えた場合、判定基準を満たす範囲内で最大の強度をとる反射点の第２位置（＝位置Ｏ（ｓ２））の位置情報を位置情報取得部２４から取得して第２位置情報として記録する。尚、原点位置Ｏから位置Ｏ（ｓ２）までの距離は距離Ｌ２に相当する。このとき、被測定物６を中間地点Ｐ０から所定量ずらして配置することにより、第１測定光と第２測定光との光路差は第１レーザ光及び第２レーザ光のコヒーレンス長よりも長くなり、よって、この位置Ｏ（ｓ２）近傍では第１測定光は干渉せず第１測定光が第２位置情報の取得に悪影響を及ぼすこともない。以上が第３の測距方法の記録ステップに相当する。 The calculation unit 20 monitors whether or not the intensity of the combined light from the light receiving unit 18 exceeds the determination criterion, and when it exceeds the determination criterion, the second reflection point having the maximum intensity within the range satisfying the determination criterion. The position information of the position (= position O (s2)) is acquired from the position information acquisition unit 24 and recorded as second position information. Note that the distance from the origin position O to the position O (s2) corresponds to the distance L2. At this time, by arranging the DUT 6 to be shifted from the intermediate point P0 by a predetermined amount, the optical path difference between the first measurement light and the second measurement light is longer than the coherence length of the first laser light and the second laser light. Therefore, in the vicinity of the position O (s2), the first measurement light does not interfere and the first measurement light does not adversely affect the acquisition of the second position information. The above corresponds to the recording step of the third distance measuring method.
　次に、演算部２０は、第１位置情報と第２位置情報と原点位置情報とから、被測定物６の第１測定点Ｓ１と第２測定点Ｓ２との間の厚み方向の距離、即ち被測定物６の厚みｔを算出する。厚みｔの算出方法は、例えば、原点位置情報をＰｏ、第１位置情報の値をＰｓ１、第２位置情報をＰｓ２とし、反射部１４が分割部１２から遠ざかるにつれ位置情報の値が増加する場合、
ｔ＝（Ｐｏ－Ｐｓ１）＋（Ｐｏ－Ｐｓ２）＝２Ｐｏ－Ｐｓ１－Ｐｓ２
となる。以上が第３の測距方法の測定ステップに相当する。 Next, the calculation unit 20 calculates the distance in the thickness direction between the first measurement point S1 and the second measurement point S2 of the object 6 to be measured, based on the first position information, the second position information, and the origin position information. The thickness t of the DUT 6 is calculated. The calculation method of the thickness t is, for example, when the origin position information is Po, the first position information value is Ps1, and the second position information is Ps2, and the position information value increases as the reflecting portion 14 moves away from the dividing portion 12. ,
t = (Po−Ps1) + (Po−Ps2) = 2Po−Ps1−Ps2
It becomes. The above corresponds to the measurement step of the third distance measuring method.
　以上のように、本発明に係る測距方法及びレーザ測距装置は、合成光の強度を随時モニタして、そのピーク強度が最大ピーク強度と略同等となる反射点の位置情報を取得し、その位置情報に基づいて被測定物までの距離もしくは被測定物の２つの測定点間の厚み方向の距離を測距する。従って、広範囲の強度データを取得する必要が無く、レーザ光の可干渉性を利用しながら比較的短時間で高精度な測距を行うことができる。 As described above, the distance measuring method and laser distance measuring device according to the present invention monitor the intensity of the combined light as needed, and acquire the position information of the reflection point whose peak intensity is substantially equal to the maximum peak intensity, Based on the position information, the distance to the object to be measured or the distance in the thickness direction between two measurement points of the object to be measured is measured. Therefore, it is not necessary to acquire a wide range of intensity data, and highly accurate distance measurement can be performed in a relatively short time while utilizing the coherence of the laser beam.
　尚、上記で示したレーザ測距装置５０ａ～５０ｃ、５１ａ～５１ｃは本発明に好適な例であるから、参照光、測定光、第１測定光、第２測定光の光路は部分的に光ファイバで置き換えても良い他、各部の構成及び各光路等は、本発明の要旨を逸脱しない範囲で変更して実施することが可能である。 Since the laser distance measuring devices 50a to 50c and 51a to 51c described above are examples suitable for the present invention, the optical paths of the reference light, measurement light, first measurement light, and second measurement light are partially optical. In addition to replacement with a fiber, the configuration of each part, each optical path, and the like can be changed and implemented without departing from the scope of the present invention.
　　　　　　６　　　被測定物
　　　　　　１２　　分割部
　　　　　　１４　　反射部
　　　　　　１６ａ　第１出射口
　　　　　　１６ｂ　第２出射口
　　　　　　１８　　受光部
　　　　　　２０　　演算部
　　　　　　２４　　位置情報取得部
　　　　　　２８　　測定光分割部
　　　　　　５０ａ～５０ｃ、５１ａ～５１ｃ　　レーザ測距装置
　　　　　　Ｓ　　　測定点
　　　　　　Ｓ１　　第１測定点
　　　　　　Ｓ２　　第２測定点
　　　　　　Ｌ　　　距離
　　　　　　ｔ　　　（被測定物の）厚み 6 Object to be measured 12 Dividing part 14 Reflecting part 16a First emitting port 16b Second emitting port 18 Light receiving unit 20 Calculation unit 24 Position information acquiring unit 28 Measuring light dividing unit 50a to 50c, 51a to 51c Laser ranging device S Measuring point S1 First measurement point S2 Second measurement point L Distance t (Measurement object) Thickness

Claims (6)

  1. 異なる中心周波数を有し且つ特定の条件を満たす２つ乃至３つのレーザ光を参照光と測定光に分割し、
    全ての参照光をその光路長を変化させる方向に移動可能な反射点で反射させるとともに全ての測定光を被測定物の測定点で反射させ、
    反射点で反射した各参照光と測定点で反射した各測定光とが合わさった合成光の強度データに基づいて被測定物の測定点までの距離を測定する測距方法であって、
    当該合成光が、参照光の光路長と測定光の光路長とが等しくなる反射点の位置で最大ピーク強度をとるとともに、
    前記特定の条件が、前記最大ピーク強度を１００％としたときに強度データにおけるその他のピーク強度が最大ピーク強度の特定のパーセンテージを超えないことであり、
    反射点の位置を移動させながら全てのレーザ光を照射してそのとき得られる合成光の強度データが最大ピーク強度と略同等のピーク強度をとる反射点の位置情報を記録する記録ステップと、
    当該位置情報と予め取得されている基準点の位置情報とに基づいて基準点から測定点までの距離を算出する測定ステップと、
    を有することを特徴とする測距方法。     Splitting two or three laser beams having different center frequencies and satisfying a specific condition into a reference beam and a measuring beam,
    Reflect all the reference light at the reflection point that can move in the direction of changing the optical path length and reflect all the measurement light at the measurement point of the object to be measured.
    A distance measurement method for measuring a distance to a measurement point of an object to be measured based on intensity data of a combined light in which each reference light reflected at a reflection point and each measurement light reflected at a measurement point are combined.
    The combined light takes the maximum peak intensity at the position of the reflection point where the optical path length of the reference light and the optical path length of the measurement light are equal,
    The specific condition is that when the maximum peak intensity is 100%, the other peak intensity in the intensity data does not exceed a specific percentage of the maximum peak intensity,
    A recording step for recording the position information of the reflection point where the intensity data of the combined light obtained by irradiating all the laser beams while moving the position of the reflection point has a peak intensity substantially equal to the maximum peak intensity,
    A measurement step for calculating a distance from the reference point to the measurement point based on the position information and the position information of the reference point acquired in advance;
    A ranging method characterized by comprising:
  2. 異なる中心周波数を有し且つ特定の条件を満たす２つ乃至３つのレーザ光を参照光と測定光に分割し、
    全ての測定光をさらに第１測定光と第２測定光とに分割し、
    全ての参照光をその光路長を変化させる方向に移動可能な反射点で反射させるとともに全ての第１測定光を被測定物の第１測定点で反射させ、さらに全ての第２測定光を被測定物の第２測定点で反射させ、
    反射点で反射した各参照光と第１測定点で反射した各第１測定光と第２測定点で反射した各第２測定光とが合わさった合成光の強度データに基づいて被測定物の第１測定点と第２測定点との間の厚み方向の距離を測定する測距方法であって、
    当該合成光が、参照光の光路長と第１測定光の光路長とが等しくなる反射点の第１位置もしくは参照光の光路長と第２測定光の光路長とが等しくなる反射点の第２位置で最大ピーク強度をとり、
    前記特定の条件が、前記最大ピーク強度を１００％としたときに強度データにおける第１位置及び第２位置以外の位置のピーク強度が最大ピーク強度の特定のパーセンテージを超えないことであり、
    反射点の位置を移動させながら全てのレーザ光を照射してそのとき得られる合成光の強度データが最大ピーク強度と略同等のピーク強度をとる反射点の第１位置の第１位置情報と第２位置の第２位置情報とを記録する記録ステップと、
    第１位置情報と第２位置情報とに基づいて第１測定点と第２測定点との間の厚み方向の距離を算出する測定ステップと、
    を有することを特徴とする測距方法。     Splitting two or three laser beams having different center frequencies and satisfying a specific condition into a reference beam and a measuring beam,
    All measurement light is further divided into first measurement light and second measurement light,
    All the reference light is reflected by a reflection point that can move in the direction of changing the optical path length, all the first measurement light is reflected by the first measurement point of the object to be measured, and all the second measurement light is received. Reflected at the second measurement point of the object to be measured,
    Based on the intensity data of the combined light in which each reference light reflected by the reflection point, each first measurement light reflected by the first measurement point, and each second measurement light reflected by the second measurement point are combined, A distance measuring method for measuring a distance in a thickness direction between a first measurement point and a second measurement point,
    The combined light is a first position of a reflection point where the optical path length of the reference light and the optical path length of the first measurement light are equal, or a first reflection point where the optical path length of the reference light and the optical path length of the second measurement light are equal. Take the maximum peak intensity at 2 positions,
    The specific condition is that when the maximum peak intensity is 100%, the peak intensity at positions other than the first position and the second position in the intensity data does not exceed a specific percentage of the maximum peak intensity,
    The first position information and the first position information of the first position of the reflection point where the intensity data of the combined light obtained by irradiating all the laser beams while moving the position of the reflection point has a peak intensity substantially equal to the maximum peak intensity. A recording step of recording second position information of two positions;
    A measurement step for calculating a distance in the thickness direction between the first measurement point and the second measurement point based on the first position information and the second position information;
    A ranging method characterized by comprising:
  3. 無測定物状態で第１測定光の光路長及び第２測定光の光路長と参照光の光路長とが等しくなる反射点の位置を原点位置情報として記録する原点取得ステップをさらに有し、
    第１測定光を被測定物の第１測定点で反射させるとともに第２測定光を第１測定点の裏面に位置する第２測定点で反射させ、
    測定ステップが第１位置情報と第２位置情報と原点位置情報とに基づいて被測定物の厚みを算出することを特徴とする請求項２記載の測距方法。     An origin acquisition step of recording, as origin position information, the position of the reflection point at which the optical path length of the first measurement light and the optical path length of the second measurement light and the optical path length of the reference light are equal in an unmeasured object state;
    Reflecting the first measurement light at the first measurement point of the object to be measured and reflecting the second measurement light at the second measurement point located on the back surface of the first measurement point;
    3. The distance measuring method according to claim 2, wherein the measuring step calculates the thickness of the object to be measured based on the first position information, the second position information, and the origin position information.
  4. 異なる中心周波数を有し且つ特定の条件を満たす２つ乃至３つのレーザ照射手段と、
    当該レーザ照射手段から出射した全てのレーザ光を参照光と測定光とに分割する分割部と、
    前記参照光を反射するとともに参照光の光路長が変化する方向に移動可能な反射部と、
    当該反射部の反射点の位置情報を取得する位置情報取得部と、
    反射部で反射した全ての参照光と被測定物の測定点で反射した全ての測定光とを受光してその合成光の強度データを出力する受光部と、
    当該強度データに基づいて前記位置情報取得部から位置情報を取得しさらに所定の演算を行う演算部と、を備え、
    前記特定の条件が、前記強度データにおける参照光の光路長と測定光の光路長とが等しくなる反射点の位置での最大ピーク強度を１００％としたときに強度データのその他のピーク強度が最大ピーク強度の特定のパーセンテージを超えないことであり、
    請求項１記載の記録ステップと測定ステップとを行い、予め設定されている基準点から測定点までの距離を測距することを特徴とするレーザ測距装置。     Two to three laser irradiation means having different center frequencies and satisfying specific conditions;
    A dividing unit that divides all laser light emitted from the laser irradiation unit into reference light and measurement light;
    A reflecting portion that reflects the reference light and is movable in a direction in which the optical path length of the reference light changes;
    A position information acquisition unit that acquires position information of a reflection point of the reflection unit;
    A light receiving unit that receives all the reference light reflected by the reflection unit and all the measurement light reflected by the measurement point of the object to be measured and outputs intensity data of the combined light;
    A calculation unit that acquires position information from the position information acquisition unit based on the intensity data and performs a predetermined calculation; and
    When the specific condition is that the maximum peak intensity at the position of the reflection point where the optical path length of the reference light and the optical path length of the measurement light are equal in the intensity data is 100%, the other peak intensities of the intensity data are maximum. Not exceed a certain percentage of peak intensity,
    2. A laser distance measuring apparatus, wherein the recording step and the measuring step according to claim 1 are performed to measure a distance from a preset reference point to the measurement point.
  5. 異なる中心周波数を有し且つ特定の条件を満たす２つ乃至３つのレーザ照射手段と、
    当該レーザ照射手段から出射した全てのレーザ光を参照光と測定光とに分割する分割部と、
    前記参照光を反射するとともに参照光の光路長が変化する方向に移動可能な反射部と、
    当該反射部の反射点の位置情報を取得する位置情報取得部と、
    前記測定光を第１測定光と第２測定光とに分割する測定光分割部と、
    第１測定光を出射する第１出射口と第２測定光を出射する第２出射口と、
    反射部で反射した全ての参照光と被測定物の第１測定点で反射した全ての第１測定光と被測定物の第２測定点で反射した全ての第２測定光とを受光してその合成光の強度データを出力する受光部と、
    当該強度データに基づいて前記位置情報取得部から第１位置情報と第２位置情報を取得しさらに所定の演算を行う演算部と、を備え、
    前記特定の条件が、前記強度データにおける参照光の光路長と第１測定光の光路長とが等しくなる反射点の第１位置もしくは参照光の光路長と第２測定光の光路長とが等しくなる反射点の第２位置での最大ピーク強度を１００％としたときに強度データにおける第１位置及び第２位置以外の位置のピーク強度が最大ピーク強度の特定のパーセンテージを超えないことであり、
    請求項２記載の記録ステップと測定ステップとを行い第１測定点と第２測定点との間の厚み方向の距離を測距することを特徴とするレーザ測距装置。     Two to three laser irradiation means having different center frequencies and satisfying specific conditions;
    A dividing unit that divides all laser light emitted from the laser irradiation unit into reference light and measurement light;
    A reflecting portion that reflects the reference light and is movable in a direction in which the optical path length of the reference light changes;
    A position information acquisition unit that acquires position information of a reflection point of the reflection unit;
    A measurement light splitting unit that splits the measurement light into a first measurement light and a second measurement light;
    A first emission port for emitting the first measurement light and a second emission port for emitting the second measurement light;
    Receiving all the reference light reflected by the reflector, all the first measurement light reflected by the first measurement point of the object to be measured, and all the second measurement light reflected by the second measurement point of the object to be measured; A light receiving unit that outputs intensity data of the combined light; and
    A calculation unit that acquires the first position information and the second position information from the position information acquisition unit based on the intensity data, and further performs a predetermined calculation;
    The specific condition is that the optical path length of the reference light and the optical path length of the first measurement light in the intensity data are equal to each other at the first position of the reflection point or the optical path length of the reference light and the optical path length of the second measurement light. When the maximum peak intensity at the second position of the reflection point is 100%, the peak intensity at positions other than the first position and the second position in the intensity data does not exceed a specific percentage of the maximum peak intensity,
    3. A laser distance measuring device, wherein the recording step and the measuring step according to claim 2 are performed to measure the distance in the thickness direction between the first measurement point and the second measurement point.
  6. 異なる中心周波数を有し且つ特定の条件を満たす２つ乃至３つのレーザ照射手段と、
    当該レーザ照射手段から出射した全てのレーザ光を参照光と測定光とに分割する分割部と、
    前記参照光を反射するとともに参照光の光路長が変化する方向に移動可能な反射部と、
    当該反射部の反射点の位置情報を取得する位置情報取得部と、
    前記測定光を第１測定光と第２測定光とに分割する測定光分割部と、
    被測定物の配置位置を挟んで対向する位置に設けられ第１測定光を出射する第１出射口と第２測定光を出射する第２出射口と、
    反射部で反射した全ての参照光と被測定物の第１測定点で反射した全ての第１測定光と第１測定点の裏面に位置する第２測定点で反射した全ての第２測定光とを受光してその合成光の強度データを出力する受光部と、
    当該強度データに基づいて前記位置情報取得部から第１位置情報と第２位置情報を取得しさらに所定の演算を行う演算部と、を備え、
    前記特定の条件が、前記強度データにおける参照光の光路長と第１測定光の光路長とが等しくなる反射点の第１位置もしくは参照光の光路長と第２測定光の光路長とが等しくなる反射点の第２位置での最大ピーク強度を１００％としたときに強度データにおける第１位置及び第２位置以外の位置のピーク強度が最大ピーク強度の特定のパーセンテージを超えないことであり、
    請求項３記載の原点取得ステップと記録ステップと測定ステップとを行い被測定物の厚みを測距することを特徴とするレーザ測距装置。     Two to three laser irradiation means having different center frequencies and satisfying specific conditions;
    A dividing unit that divides all laser light emitted from the laser irradiation unit into reference light and measurement light;
    A reflecting portion that reflects the reference light and is movable in a direction in which the optical path length of the reference light changes;
    A position information acquisition unit that acquires position information of a reflection point of the reflection unit;
    A measurement light splitting unit that splits the measurement light into a first measurement light and a second measurement light;
    A first emission port that emits first measurement light and a second emission port that emits second measurement light, which are provided at positions facing each other with the arrangement position of the object to be measured;
    All of the reference light reflected by the reflection unit, all of the first measurement light reflected by the first measurement point of the object to be measured, and all of the second measurement light reflected by the second measurement point located on the back surface of the first measurement point And a light receiving unit that outputs the intensity data of the combined light,
    A calculation unit that acquires the first position information and the second position information from the position information acquisition unit based on the intensity data, and further performs a predetermined calculation;
    The specific condition is that the optical path length of the reference light and the optical path length of the first measurement light in the intensity data are equal to each other at the first position of the reflection point or the optical path length of the reference light and the optical path length of the second measurement light. When the maximum peak intensity at the second position of the reflection point is 100%, the peak intensity at positions other than the first position and the second position in the intensity data does not exceed a specific percentage of the maximum peak intensity,
    4. A laser distance measuring device comprising: measuring the thickness of an object to be measured by performing the origin acquisition step, the recording step, and the measurement step according to claim 3.
PCT/JP2009/070585 2009-12-09 2009-12-09 Distance measuring method and laser distance measuring apparatus WO2011070656A1 (en)

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Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN102494615A (en) * 2011-11-15 2012-06-13 清华大学 Step distance measuring device based on femtosecond optical-frequency comb and measuring method thereof
CN102679886A (en) * 2012-05-25 2012-09-19 孙富亮 Method and device for measuring brake down-slide distance of crane
CN113885042A (en) * 2021-08-17 2022-01-04 哈尔滨工业大学 1.55 mu m single photon coherent laser radar detection method and device

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS61105805U (en) * 1984-12-17 1986-07-05
JP2005274550A (en) * 2003-09-03 2005-10-06 Ricoh Co Ltd Laser length measuring machine, and original optical disk exposure device
WO2008099788A1 (en) * 2007-02-13 2008-08-21 Naoyuki Koyama Distance measuring method and laser distance measuring device
JP2009115486A (en) * 2007-11-02 2009-05-28 National Institute Of Advanced Industrial & Technology Length measuring method by coincidence method of low coherence interference

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS61105805U (en) * 1984-12-17 1986-07-05
JP2005274550A (en) * 2003-09-03 2005-10-06 Ricoh Co Ltd Laser length measuring machine, and original optical disk exposure device
WO2008099788A1 (en) * 2007-02-13 2008-08-21 Naoyuki Koyama Distance measuring method and laser distance measuring device
JP2009115486A (en) * 2007-11-02 2009-05-28 National Institute Of Advanced Industrial & Technology Length measuring method by coincidence method of low coherence interference

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN102494615A (en) * 2011-11-15 2012-06-13 清华大学 Step distance measuring device based on femtosecond optical-frequency comb and measuring method thereof
CN102679886A (en) * 2012-05-25 2012-09-19 孙富亮 Method and device for measuring brake down-slide distance of crane
CN113885042A (en) * 2021-08-17 2022-01-04 哈尔滨工业大学 1.55 mu m single photon coherent laser radar detection method and device

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