JP5911987B1 - Laser distance measuring device - Google Patents

Abstract

Generation of stray light is reduced in a laser range finder using a reflecting member having a transparent layer formed on the surface. A distance measuring device (1) includes a light shielding portion (17) on a surface of a deflection member (3). The light shielding portion (17) includes an incident light reflecting portion that reflects the laser light (LL) emitted from the light emitting element (2) toward the outside, and a measurement light (RL) reflected by an external object as the light receiving element (8). ) Is provided at a boundary portion with the measurement light reflecting portion to be reflected toward. [Selection] Figure 1

Description

  The present invention relates to a laser distance measuring apparatus that measures a distance by scanning a laser beam.

  As an apparatus (laser distance measuring apparatus) for measuring a distance by scanning a laser beam, apparatuses described in Patent Documents 1 to 4 are known. The laser distance measuring devices described in Patent Documents 1 to 4 reflect light emitted from a light source by a deflecting member (reflecting member) and detect reflected light from an object (measurement object).

  For example, the laser distance measuring devices described in Patent Documents 3 and 4 have a configuration in which the direction of laser light emitted from a light emitter (light source) is deflected by being reflected by a central portion of a deflecting member (reflecting member). Further, by rotating the deflecting member, the monitoring area is periodically scanned with the laser beam. If there is an object in the monitoring area, the laser light is diffusely reflected on the surface of the object, and the diffusely reflected light is reflected on the periphery of the deflecting member and reflected toward the photodetector, It is detected in a photodetector. The angle position of the object is estimated from the angle setting of the deflecting member, and the distance from the laser distance measuring device to the object is estimated based on the passage time of the laser beam and the speed of the light.

  On the other hand, in such a laser distance measuring device, various deflecting members are used. For example, in the laser distance measuring devices described in Patent Documents 1 and 2, a deflection member having a deflection surface (reflection surface) on which a metal film such as gold or aluminum is formed is used.

JP 2009-229255 A (released on October 8, 2009) JP 2011-214926 A (released October 27, 2011) JP2012-1312917A (released on July 12, 2012) JP 2012-68243 A (published April 5, 2012)

  In the laser distance measuring devices described in Patent Documents 1 and 2, a deflection mirror in which a metal film such as gold or aluminum is formed on a deflection surface is used as a deflection member (reflection member). In such a mirror, light is reflected on the surface of the metal film. However, a mirror using reflection on the surface of the metal film is easily scratched on the surface of the metal film due to the characteristic that a very thin metal film is formed on the surface. For this reason, a transparent layer for protecting the metal film may be formed as a protective film on the surface of the metal film.

  Further, as a system other than the deflection mirror using the above metal film, a system using a dielectric multilayer mirror as a deflection member (reflection member) can be considered. The dielectric multilayer mirror includes a reflective film in which a high-refractive index dielectric layer and a low-refractive index dielectric layer are alternately stacked, and includes a high-refractive index dielectric layer and a low-refractive index dielectric layer. Reflects light at the interface. Such a dielectric multilayer mirror is generally more resistant to scratches on the surface and has a higher reflection efficiency than a mirror utilizing reflection on a metal film.

  However, even when any of the above-described mirrors is used, when a deflecting member having a transparent layer formed on the surface is used, light enters the transparent layer and stray light is generated from the deflecting member. Will occur.

  Specifically, for example, the laser distance measuring devices described in Patent Documents 3 and 4 deflect the direction of the laser light emitted from the light source at the center of the deflecting member and emit it to the outside. The configuration is such that the reflected light from the object to be measured is deflected around the deflecting member to guide the light to the photodetector side. In this case, if a transparent layer is formed on the surface of the deflecting member, a part of the laser light emitted from the light source and incident on the central portion of the deflecting member may ooze out around the deflecting member. , Stray light occurs.

  The term “light oozing” as used herein means that all of the light that has entered the transparent layer from the surface of the transparent layer formed on the surface of the deflecting member is reflected on the deflecting surface (reflecting surface) by a single reflection. Rather than being emitted from the surface to the outside, this is a phenomenon in which part of the light repeatedly reflects a plurality of times between the deflecting surface and the surface of the transparent layer, and the light enters the inside of the transparent layer. When light enters the inside of the transparent layer, the invading light is repeatedly reflected several times between the deflecting surface (reflecting surface) and the surface of the transparent layer, and finally deviated from the originally intended part. Light is emitted to the outside of the deflecting member. The light thus emitted becomes light that is not originally intended, that is, “stray light”. When such stray light is detected by the photodetector, it is erroneously recognized as reflected light from the object, and accurate measurement cannot be performed.

  The present invention has been made in view of the above-described problems, and an object thereof is to reduce the generation of stray light in a laser distance measuring apparatus using a reflecting member having a transparent layer formed on the surface thereof.

  In order to solve the above problems, a laser distance measuring device according to an aspect of the present invention includes a light emitting unit that emits laser light, a light receiving unit that receives measurement light reflected by an external object, and the laser light; A reflective surface having a transparent layer formed on the surface, an incident light reflecting part for reflecting laser light emitted from the light emitting part toward the outside, and a measuring light reflected by the external object toward the light receiving part A reflecting member having a measurement light reflecting part to be reflected, and a light shielding part provided on at least a part of a boundary part between the incident light reflecting part and the measuring light reflecting part on the surface of the reflecting member. Features.

  According to one aspect of the present invention, in a laser distance measuring device using a reflecting member having a transparent layer formed on the surface, the effect of reducing the occurrence of stray light can be achieved.

It is front sectional drawing which shows the structure of the ranging device which concerns on Embodiment 1 of this invention. It is a perspective view which shows the structure of the ranging apparatus which concerns on Embodiment 1 of this invention. It is a top view of the deflection | deviation member of the distance measuring device which concerns on Embodiment 1 of this invention. It is a figure which shows the formation method of the light-shielding part in the distance measuring device which concerns on Embodiment 1 of this invention. It is a figure which shows the stray light produced by a deflection | deviation member, Comprising: (a) is front sectional drawing for demonstrating the progress of the stray light in the distance measuring device of a comparative example, (b) is the distance measuring device based on Embodiment 1. FIG. It is front sectional drawing for demonstrating the progress of a stray light. FIG. 6 is a diagram illustrating a light reception signal detected by the distance measuring device of FIG. 5, wherein (a) is a waveform diagram illustrating a light reception signal in the conventional distance measuring device, and (b) is a distance measuring device according to the first embodiment. It is a wave form diagram which shows the light-receiving signal in. It is a figure which shows the formation part of the light-shielding part in the distance measuring device which concerns on Embodiment 2 of this invention. It is a figure which shows the formation site | part of the light-shielding part in the distance measuring device which concerns on Embodiment 3 of this invention. It is front sectional drawing which shows the structure of the ranging device which concerns on Embodiment 4 of this invention. It is a figure which shows the stray light produced by being reflected by the light transmission part, Comprising: (a) is front sectional drawing for demonstrating the progress of the stray light in the ranging apparatus which concerns on Embodiment 1, (b) is embodiment. 6 is a front sectional view for explaining the progress of stray light in the distance measuring device according to FIG.

  Hereinafter, embodiments of the present invention will be described in detail.

Embodiment 1
(Configuration of ranging device 1 (laser ranging device))
A configuration of the distance measuring apparatus 1 according to the first embodiment will be described with reference to FIGS.

  FIG. 1 is a front sectional view showing a configuration of a distance measuring device 1 (laser distance measuring device) according to the first embodiment. FIG. 2 is a perspective view showing the configuration of the distance measuring device 1.

  As shown in FIGS. 1 and 2, the distance measuring device 1 includes a light emitting element 2 (light emitting unit) that emits a laser beam LL. The light emitting element 2 is attached to the side surface of the fixing member 15 made of sheet metal. The laser light LL emitted from the light emitting element 2 is converted into parallel light by the lens 11. The laser beam LL converted into parallel light by the lens 11 is reflected by the mirror 12.

  The distance measuring device 1 includes a substantially square plate-shaped deflecting member 3 (reflecting member) that further reflects the laser beam LL reflected by the mirror 12. The deflecting member 3 is disposed along a direction inclined about 45 degrees with respect to the traveling direction of the laser light LL reflected by the mirror 12, and is attached to the attachment member 13.

  The deflection member 3 is formed from an optical element such as a glass mirror. The deflection member 3 includes a reflecting surface 3a and a transparent layer 3b formed on the surface of the reflecting surface 3a. The reflecting surface 3a is formed from, for example, a mirror-finished metal film such as glass, gold, or aluminum. The transparent layer 3b protects the reflective surface 3a, and is formed of a dielectric multilayer film in this embodiment. That is, the deflecting member 3 of the present embodiment is a dielectric multilayer mirror in which the surface of the reflecting surface 3a is coated with a transparent layer 3b made of a dielectric difference layer film. Since the dielectric multilayer film has a high reflectance, the light incident on the deflecting member 3 can be reflected with high efficiency by using the dielectric multilayer film as the transparent layer 3b.

  The attachment member 13 is fixed to a motor 14 that rotates around the rotation axis RX. The motor 14 is fixed to the upper part of the fixing member 15. The deflection member 3 can be rotated by the motor 14 along the rotation axis RX along the incident direction of the laser beam LL.

  A laser beam passage member 9 (optical path member) is provided at the center of the deflection member 3. The laser beam passage member 9 is composed of an inverted L-shaped pipe. The laser light passage member 9 is formed with optical paths 9a and 9b having a circular cross section. The optical paths 9a and 9b are holes (tubular holes) through which the laser light LL passes. The optical path 9 a causes the laser beam LL emitted from the light emitting element 2 to enter the deflection member 3. The optical path 9b emits the laser beam LL incident on the deflecting member 3 through the optical path 9a to the outside. The optical path 9a allows the laser light LL to pass in the vertical direction so as to block the spreading component of the laser light LL reflected by the mirror 12. The optical path 9b passes the laser beam LL in the horizontal direction so as to block the spread component of the laser beam LL reflected by the deflecting member 3.

  As described above, when the laser beam LL reflected by the mirror 12 enters the laser beam passage member 9, the laser beam LL passes through the optical path 9 a and is guided to the deflection member 3. The laser beam LL reflected by the deflecting member 3 passes through the optical path 9b and is emitted to the outside.

  The laser light passing member 9 has an opening formed by obliquely cutting a bent portion of the inverted L-shaped pipe (joint portion between the optical path 9a and the optical path 9b). Is in contact with the center of the surface of the deflection member 3. Between the surface of the deflection member 3 and the outer surface of the optical path 9a, a light shielding portion 17 that shields stray light generated by the deflection member 3 is formed. As will be described later, in this embodiment, the light shielding portion 17 is coated with an adhesive. Therefore, the deflection member 3 and the laser beam passage member 9 (optical path 9a) are bonded in the region where the light shielding portion 17 is formed. Details of the light shielding unit 17 will be described later.

  The distance measuring device 1 is provided with a cover 5 provided so as to cover the light emitting element 2, the deflecting member 3, the laser light passing member 9, the mounting member 13, the motor 14, and the fixing member 15. In FIG. 2, the cover 5 is omitted. The cover 5 is formed with a light transmitting portion 6 for transmitting the laser light LL that has passed through the laser light transmitting member 9.

  The laser beam LL that has passed through the optical path 9b of the laser beam passage member 9 is transmitted through the light transmitting portion 6 of the cover 5 and projected to the external space. If there is an object in the external space, the laser beam LL is reflected by the surface of the object, and the measurement beam RL that is the reflected beam is transmitted again through the light transmitting portion 6 of the cover 5 from the opposite direction to the laser beam LL.

  As described above, the laser light LL emitted from the light emitting element 2 and the measurement light RL reflected by the object in the external space travel on the same path, and both pass through the light transmitting portion 6 of the cover 5. The transmitted measurement light RL is reflected by the deflecting member 3, and the reflected light is collected by the lens 16 fixed to the bottom of the fixing member 15 and reaches the light receiving element (light receiving unit) 8.

  The distance measuring device 1 has an arithmetic processing device 10. Arithmetic processing device 10 is based on the time difference between the laser pulse of laser beam LL projected from light emitting element 2 and the laser pulse of measurement light RL reflected by the object and received by light receiving element 8. Find the distance.

(Deflection member 3 and laser beam passage member 9)
Next, the deflection member 3 and the laser beam passage member 9 will be described in detail with reference to FIG. FIG. 3 is a plan view of the deflecting member 3 of the distance measuring device 1.

  The deflecting member 3 receives incident laser light LL emitted from the light emitting element 2 and reflected by the mirror 12, and incident light reflecting region (incident light reflecting portion) 3c for emitting the incident light (laser light LL) to the outside. And a measurement light reflection region (measurement light reflection part) 3d for reflecting the measurement light RL reflected by an external object toward the light receiving element 8 (see FIGS. 1 and 2).

  Specifically, in this embodiment, as shown in FIG. 3, a circular incident light reflection region 3c is formed at the center of the surface of the deflecting member 3, and the measurement light is formed at the periphery of the incident light reflection region 3c. A reflection region 3d is formed. And the opening part formed in the bending part (joint part of the optical path 9a and the optical path 9b) of the laser beam passage member 9 is contacting along the outer edge part of the incident light reflection area | region 3c.

  Thereby, the laser beam LL emitted from the light emitting element 2 and reflected by the mirror 12 enters the optical path 9a from the opening (laser beam passing hole) of the optical path 9a of the laser beam passing member 9, passes through the optical path 9a, and is deflected. The light enters the incident light reflection region 3 c of the member 3. The laser beam LL incident on the incident light reflection region 3c is deflected by about 90 ° by the incident light reflection region 3c, passes through the optical path 9b, and is emitted toward the outside. Thus, the laser beam passage member 9 is configured so that the laser beam LL reflected by the mirror 12 is incident on the incident light reflection region 3c of the deflection member 3 and is not incident on the measurement light reflection region 3d.

  On the other hand, if there is an object in the external space, the laser light LL emitted to the outside is reflected on the surface of the object, and the measurement light RL is incident on the deflecting member 3 again from the direction opposite to the laser light LL. The measurement light RL is incident on the measurement light reflection region 3d of the deflection member 3 without passing through the laser light passage member 9 (optical paths 9a and 9b). The measurement light RL incident on the measurement light reflection region 3d is reflected by about 90 ° by the measurement light reflection region 3d and is emitted toward the light receiving element 8.

  As described above, the laser light passage member 9 spatially separates the laser light incident on the incident light reflection region 3c and the measurement light RL incident on the measurement light reflection region 3d. The laser beam passage member 9 is in contact with the surface of the deflection member 3. Furthermore, the optical path 9a of the laser beam passage member 9 is a hole through which the laser beam LL passes, and the incident area of the laser beam LL emitted from the light emitting element 2 to the deflection member 3 is incident by the optical path 9a. It is limited to the light reflection region 3c.

  The shapes and areas of the incident light reflection region 3c and the measurement light reflection region 3d in the deflecting member 3 are not limited to the configuration shown in FIG. 3, and can be arbitrarily set.

(Formation method of the light-shielding part 17)
Next, a method for forming the light shielding portion 17 will be described with reference to FIG. FIG. 4 is a diagram illustrating a method for forming the light shielding portion 17 in the distance measuring device 1.

  In the present embodiment, as shown in FIG. 4, the light shielding portion 17 is formed by painting the surface of the bonding portion 17 a between the deflection member 3 and the laser beam passage member 9 with a paint. That is, in order to form the light shielding portion 17, first, the adhesive portion 17 a is formed between the surface of the deflecting member 3 and the outer surface of the optical path 9 a of the laser light passing member 9. A pocket (not shown) is formed on the outer surface of the optical path 9a. The adhesive portion 17a can be formed by filling the pocket with a transparent adhesive. Next, a light-shielding paint is filled in this pocket in the same manner. Thereby, the light-shielding part 17 by which the surface of the adhesion part 17a was painted with the light-shielding paint is formed. Thus, the light shielding part 17 can be formed by a simple process of applying the light shielding paint to the surface of the adhesive part 17a.

  In FIG. 4, the surface of the adhesive portion 17a is coated with a light-shielding paint, and the adhesive portion 17a and the light-shielding portion 17 are formed in the same region. However, the light shielding portion 17 may be formed by applying a light shielding coating directly on the surface of the deflection member 3. That is, the adhesive portion 17a and the light shielding portion 17 may be formed in different areas. Also in this case, the light shielding portion 17 can be formed by a simple process of applying a light shielding paint to the surface of the deflecting member 3.

  In FIG. 4, the light shielding portion 17 is formed by painting an adhesive portion 17 a made of a transparent adhesive with a light shielding paint. However, the light shielding part 17 can also be formed from a light shielding adhesive. Thereby, the light shielding part 17 has both the function of shielding stray light from the deflecting member 3 and the function of bonding the deflecting member 3 and the laser light passing member 9 together. Further, the adhesion between the deflecting member 3 and the laser beam passing member 9 and the formation of the light shielding portion 17 can be performed simultaneously. Therefore, the configuration and manufacturing process of the distance measuring device 1 can be simplified.

(Operation of the distance measuring device 1)
FIG. 5 is a diagram illustrating stray light generated by the deflecting member 3. FIG. 5A is a front cross-sectional view for explaining the progress of stray light STL1 in the distance measuring device 91 of the comparative example. FIG. 6B is a front cross-sectional view for explaining the progression of stray light STL1 in the distance measuring apparatus 1 according to the first embodiment.

  As shown in FIG. 5 (a), in the distance measuring device 91 of the comparative example, the adhesive portion 17a is transparent, whereas in the distance measuring device 1, as shown in FIG. 5 (b), it is transparent. A light shielding portion 17 is formed in which the surface of the bonding portion 17a is coated with a light shielding paint.

  As shown in FIG. 5A, when the deflecting member 3 having the transparent layer 3 b formed on the surface is used, light enters the transparent layer 3 b and stray light STL <b> 1 is generated from the deflecting member 3. Specifically, when the transparent layer 3b is formed on the surface of the deflection member 3, a part of the laser beam LL emitted from the light emitting element 2 and incident on the central portion (incident light reflection region 3c) of the deflection member 3 is formed. As the light oozes out in the peripheral portion (measurement light reflection region 3d) of the deflection member 3, stray light SLT is generated.

  The term “light oozing” used here means that all of the laser light LL incident on the transparent layer 3b from the surface of the transparent layer 3b formed on the surface of the deflecting member 3 is reflected once on the reflecting surface 3a (normally Rather than being emitted from the surface of the transparent layer 3b by reflection), a part of the laser light LL is repeatedly reflected a plurality of times between the surface of the reflective surface 3a and the surface of the transparent layer 3b. This is a phenomenon in which the laser beam LL enters inside. When the laser beam LL enters the inside of the transparent layer 3b, the laser beam LL that has entered repeatedly reflects a plurality of times between the reflecting surface 3a and the surface of the transparent layer 3b, and finally, from the originally intended portion. The laser beam LL is emitted to the outside of the deflecting member 3 from the deviated position (from the measurement light reflection region 3d via the adhesive portion 17a). The light thus emitted becomes “stray light STL1”. When such stray light STL1 passes through the lens 16 and is detected by the light receiving element 8, it is erroneously recognized as measurement light RL from the measurement object. Therefore, the distance measuring device 91 of the comparative example shown in FIG. 5A cannot perform accurate measurement.

  In particular, the laser light LL emitted from the light emitting element 2 is overwhelmingly stronger than the measurement light RL reflected by the measurement object. For this reason, if even a very small amount of stray light STL1 is detected by the light receiving element 8, it greatly affects the decrease in measurement accuracy. Further, even if the incident region of the laser beam LL on the deflecting member is limited to the incident light reflection region 3c by the optical path 9a of the laser beam passage member 9, the stray light STL1 leaks from the transparent adhesive portion 17a. Generation of STL1 cannot be prevented.

  Therefore, as shown in FIG. 5B, in the distance measuring device 1, a light shielding unit that shields stray light STL <b> 1 generated when a part of the laser light LL incident on the deflecting member 3 enters the inside of the transparent layer 3 b. 17 is formed. The light shielding portion 17 is provided at the boundary between the incident light reflection region 3c and the measurement light reflection region 3d. In FIG. 5B, the inside of the region where the laser light passage member 9 is in contact with the surface of the deflection member 3 corresponds to the incident light reflection region 3c, and the outside of the region corresponds to the measurement light reflection region 3d. . In the present embodiment, the light shielding portion 17 (adhesive portion 17 a) is formed on the lower side (side closer to the light receiving element 8) than the region where the laser light passage member 9 is in contact with the surface of the deflection member 3.

  FIG. 6 is a diagram showing light reception signals detected by the distance measuring devices 1 and 91 of FIG. 5, and FIG. 6A is a waveform diagram showing light reception signals in the distance measuring device 91 of the comparative example, and FIG. FIG. 4 is a waveform diagram showing a light reception signal in the distance measuring apparatus 1 according to the first embodiment.

  As shown in FIG. 6A, when the light shielding portion 17 is not formed (the transparent adhesive portion 17a), stray light STL1 is generated. Therefore, the stray light reception signal S2 by the stray light STL1 and the correct light reception signal S1 Is measured. For this reason, when the reflectance of the object in the external space is low or the distance from the object is short, it is difficult to distinguish the stray light reception signal S2 and the light reception signal S1, and the ranging accuracy is deteriorated.

  On the other hand, as shown in FIG. 6B, when the light shielding portion 17 is formed, the stray light STL1 is shielded, so that the stray light due to the stray light STL1 seen in the waveform diagram of FIG. It can be seen that the generation of the light reception signal S2 is suppressed.

  As described above, in the distance measuring apparatus 1, the light shielding portion 17 is formed at the boundary between the incident light reflection region 3c and the measurement light reflection region 3d where stray light STL1 due to the deflection member 3 is likely to be generated. As a result, even if stray light STL1 is generated from the deflecting member 3 due to a part of the laser light LL incident on the incident light reflection region 3c entering the transparent layer 3b, the stray light STL1 is shielded by the light shielding portion 17. Is done. Therefore, the generation of stray light STL1 from the deflecting member 3 can be reduced. Therefore, in the distance measuring device 1 using the deflection member 3 having the transparent layer 3b formed on the surface, the stray light STL1 generated by the deflection member 3 can be reduced, and the distance measuring device 1 with high measurement accuracy can be provided. .

  Further, in the distance measuring device 1, the cylindrical (tubular) laser light passage member 9 in which the optical path 9 a for allowing the laser light LL emitted from the light emitting element 2 to enter the incident light reflection region 3 c of the deflection member 3 is formed. I have. Thereby, since the incident position of the laser light LL emitted from the light emitting element 2 is defined by the optical path 9a, the laser light LL emitted from the light emitting element 2 is incident on the incident light reflection region 3c of the deflecting member 3, It does not enter the measurement light reflection region 3d. For this reason, the laser beam LL incident on the incident light reflection region 3c and the measurement light RL incident on the measurement light reflection region 3d are separated. Therefore, it can be reduced that the laser light LL emitted from the light emitting element 2 enters the measurement light reflecting region 3d of the deflecting member 3 and is received by the light receiving element 8 as stray light different from the stray light STL1.

  In the distance measuring apparatus 1, the optical path 9a of the laser beam passage member 9 is formed from a hole through which the laser beam LL passes. Thereby, the laser beam LL emitted from the light emitting element 2 can be reliably incident on the incident light reflecting region 3c through the hole (optical path 9a).

  Moreover, in the distance measuring device 1, the incident region of the laser light LL emitted from the light emitting element 2 is limited to the incident light reflecting region 3 c by the optical path 9 a formed in the laser light passage member 9. Therefore, it is possible to separate light (laser light LL) incident on the incident light reflection region 3c and light (measurement light RL) incident on the measurement light reflection region 3d.

  On the other hand, in the distance measuring device 1, the opening formed in the bent portion of the laser beam passage member 9 is in direct contact with the surface of the deflection member 3. More specifically, the optical path 9 a formed in the laser beam passage member 9 is in direct contact with the outer edge portion of the incident light reflection region 3 c on the surface of the deflection member 3. And the light-shielding part 17 is formed in the area | region by the side of the light receiving element 8 which is a part of outer peripheral part of this contact part.

  In this configuration, since the optical path 9a formed in the laser light passage member 9 has a contact portion that directly contacts the outer edge portion of the incident light reflection region 3c, the laser light passage member 9 and the deflection member 3 are interposed between them. No gap is formed. Thereby, the laser beam LL emitted from the light emitting element 2 is reliably incident on the incident light reflection region 3 c of the deflecting member 3. For this reason, the laser light LL incident on the incident light reflection region 3c and the measurement light RL incident on the measurement light reflection region 3d are completely separated. Further, the light shielding portion 17 is formed in a region on the light receiving element 8 side which is a part of the outer peripheral portion of the contact portion. Therefore, the generation of stray light STL1 due to light oozing out into the measurement light reflection region 3d can be reduced more reliably.

  However, when the light shielding part 17 is formed on the surface of the deflection member 3 in this way, generation of stray light STL1 can be suppressed. On the other hand, if the area of the light shielding portion 17 is too large, the measurement light reflection region 3d that reflects the measurement light RL from the object and guides it to the light receiving element 8 is shielded, so that the effective area of the measurement light reflection region 3d is small. It will decrease. As a result, the light shielding unit 17 also shields the measurement light RL reflected by the measurement light reflection region 3d of the deflecting member 3, so that the light detection efficiency in the light receiving element 8 is lowered. Thus, there is a trade-off relationship between the formation of the light shielding portion 17 and the decrease in light detection efficiency.

  Therefore, in the present embodiment, the light shielding portion 17 is provided in a region close to the light receiving element 8 (below the laser light passing member 9) in the inclined deflecting member 3. Since this region is a region where the ratio of stray light STL1 emitted toward the light receiving element 8 is high, the emission of stray light STL1 can be efficiently suppressed.

  Specifically, in the distance measuring device 1, the surface of the deflecting member 3 is inclined with respect to the direction in which the laser light LL emitted from the light emitting element 2 and reflected by the mirror 12 enters the incident light reflecting region 3c. It has become. That is, the deflecting member 3 is disposed to be inclined with respect to the light receiving element 8. The light shielding portion 17 is formed along a region approaching the light receiving element 8 from a boundary portion between the incident light reflection region 3c and the measurement light reflection region 3d on the surface of the deflection member 3.

  As described above, when the deflection member 3 is arranged to be inclined with respect to the light receiving element 8, the light receiving element 8 is approached from the boundary between the incident light reflection region 3 c and the measurement light reflection region 3 d on the surface of the deflection member 3. As a result, the ratio at which the stray light STL1 generated by the deflecting member 3 is detected by the light receiving element 8 increases.

  In the present embodiment, the light shielding portion 17 is formed along the region where the ratio of the stray light STL1 generated by the deflecting member 3 is detected by the light receiving element 8 is high. Thereby, it is possible to reliably reduce the detection of the stray light STL1 by the light receiving element 8 while reducing the area where the light shielding portion 17 is formed. Furthermore, the region where the light shielding portion 17 is not formed can be widely used as the measurement light reflection region 3d. As a result, the light detection efficiency of the measurement light RL by the light receiving element 8 can be reduced by narrowing the measurement light reflection region 3d. Therefore, it is possible to minimize the decrease in the light detection efficiency of the measurement light RL while preventing the stray light STL1 from being generated by the light shielding unit 17.

[Embodiment 2]
The following will describe another embodiment of the present invention with reference to FIG. For convenience of explanation, members having the same functions as those described in the embodiment are given the same reference numerals, and descriptions thereof are omitted. FIG. 7 is a diagram illustrating a portion where the light shielding unit 17 is formed in the distance measuring apparatus according to the second embodiment.

  In the distance measuring apparatus 1 according to the first embodiment, as shown in FIG. 5B, the contact area between the deflection member 3 and the laser beam passage member 9 in the deflection member 3 inclined with respect to the light receiving element 8. The light shielding portion 17 was formed in a region below the outer peripheral portion (region close to the light receiving element 8) of the (outer edge portion of the incident light reflecting region 3c).

  On the other hand, in this embodiment, as shown in FIG. 7, the light shielding portions 17 are formed on both sides (both sides) near the center of the contact area between the deflection member 3 and the laser beam passage member 9. Similarly to the first embodiment, such a light-shielding portion 17 can be simply obtained by filling the pocket formed on the outer surface of the laser light transmitting member 9 with a transparent adhesive and then coating the surface of the transparent adhesive with a light-shielding paint. The light shielding part 17 can be formed by a simple process. The light shielding part 17 may be formed of a light shielding adhesive.

  According to the present embodiment, the light shielding portion 17 is formed at the boundary between the incident light reflection region 3c and the measurement light reflection region 3d where stray light STL1 due to the deflection member 3 is likely to be generated. Therefore, the generation of stray light STL1 from the deflecting member 3 can be more reliably reduced.

[Embodiment 3]
The following will describe another embodiment of the present invention with reference to FIG. For convenience of explanation, members having the same functions as those described in the embodiment are given the same reference numerals, and descriptions thereof are omitted.

  The light shielding portion 17 of the first and second embodiments is formed in a part of the outer peripheral portion of the contact region (the outer edge portion of the incident light reflecting region 3c) between the deflecting member 3 and the laser light passing member 9.

  On the other hand, in the present embodiment, as shown in FIG. 8, the light shielding portion 17 is formed in the entire outer peripheral portion of the contact region between the deflection member 3 and the laser beam passage member 9. Similarly to the first embodiment, such a light-shielding portion 17 can be simply obtained by filling the pocket formed on the outer surface of the laser light transmitting member 9 with a transparent adhesive and then coating the surface of the transparent adhesive with a light-shielding paint. The light shielding part 17 can be formed by a simple process. The light shielding part 17 may be formed of a light shielding adhesive.

  According to the present embodiment, the light shielding portion 17 is formed at the boundary between the incident light reflection region 3c and the measurement light reflection region 3d where stray light STL1 due to the deflection member 3 is likely to be generated. In addition, the light shielding portion 17 is formed in the entire outer peripheral portion of the incident light reflecting region 3c. Therefore, the generation of stray light STL1 from the deflecting member 3 can be more reliably reduced.

[Embodiment 4]
Another embodiment of the present invention will be described below with reference to FIGS. 9 and 10. For convenience of explanation, members having the same functions as those described in the embodiment are given the same reference numerals, and descriptions thereof are omitted.

  FIG. 9 is a front sectional view showing the configuration of the distance measuring apparatus 1a according to the fourth embodiment. FIG. 10 is a diagram illustrating the stray light STL2 generated by being reflected by the light transmission unit 6. FIG. 10A is a front cross-sectional view for explaining the progression of the stray light STL2 in the distance measuring apparatus 1 according to the first embodiment. FIG. 6B is a front sectional view for explaining the progression of stray light STL2 in the distance measuring device 1a according to the fourth embodiment. The distance measuring device 1a of the fourth embodiment is different from the distance measuring device 1 of the first embodiment in that the light shielding member 18 is provided.

  Specifically, as shown in FIG. 9, the light shielding member 18 is adjacent to the lower side of the optical path 9b that emits the laser light LL incident on the deflecting member 3 through the optical path 9a of the laser light passing member 9 to the outside. Is formed. That is, the laser beam passage member 9 and the light shielding member 18 are integrally configured. The light shielding member 18 shields stray light STL2 generated as a part of the laser light LL is reflected by the light transmitting portion 6 as described later. The light shielding member 18 has a cylindrical (box-shaped) concave portion that opens to face the light transmitting portion 6. The cylindrical recess is formed in parallel with the optical path 9 b of the laser beam passage member 9. The light shielding member 18 is arranged so that the stray light STL2 reaches the recess.

  The operation of the light shielding member 18 provided in the distance measuring device 1a of the present embodiment will be described with reference to FIG. As shown in FIG. 10A, the distance measuring apparatus 1 according to the first embodiment is not provided with the light shielding member 18. On the other hand, as shown in FIG. 10B, a light shielding member 18 is provided in the distance measuring device 1a.

  As shown in FIG. 10A, in the distance measuring apparatus 1 according to the first embodiment, when the light transmitting portion 6 of the cover 5 exists on the path of the laser light LL emitted to the external space, the laser light LL A part of the light is reflected on the surface of the light transmitting portion 6, and the reflected light becomes stray light STL <b> 2 and reaches the light receiving element 8 through the lens 16.

  On the other hand, in the distance measuring device 1a of the fourth embodiment shown in FIG. 10B, the light shielding member 18 having a box-shaped concave portion is formed on the deflection member 3. For this reason, the stray light STL2 is reflected by the surface of the light transmitting portion 6 and reaches the recess. Accordingly, the stray light STL2 can be shielded by the light shielding member 18 by reflecting and attenuating the reflected light that causes the stray light STL2 by the inner wall of the recess.

  Also, stray light STL2 is generated in a compact shape with a reduced capacity and size by providing a light shielding member 18 having a box-shaped recess in the deflection member 3 near the light transmission portion 6 of the cover 5 serving as a reflection source. Can be prevented. Furthermore, by forming the concave portion in a box shape, it is possible to suppress the generation of further reflected light that is the source of the stray light STL2.

  Further, in the distance measuring device 1 a, the light shielding portion 17 is formed on the extension line of the concave portion of the light shielding member 18. As a result, the stray light STL1 generated by entering the inside of the transparent layer 3b and the stray light STL2 generated by reflecting a part of the laser light LL by the light transmitting portion 6 are shielded by the light shielding portion 17 and the light shielding member 18, respectively. can do. Therefore, it is possible to provide a distance measuring device 1a that can perform accurate measurement with few false detections due to stray light STL1 and STL2.

  In the present embodiment, the laser light passage member 9 and the light shielding member 18 are integrally formed. However, the present invention is not limited to this form, and the laser light passage member 9 and the light shielding member 18 are separate. It may be configured.

  The present invention is not limited to the above-described embodiments, and various modifications are possible within the scope shown in the claims, and embodiments obtained by appropriately combining technical means disclosed in different embodiments. Is also included in the technical scope of the present invention. Furthermore, a new technical feature can be formed by combining the technical means disclosed in each embodiment.

[Summary]
The laser distance measuring device (ranging device 1, 1a) according to aspect 1 of the present invention includes a light emitting unit (light emitting element 2) that emits laser light LL, and measurement light RL that is reflected by an external object. A light receiving part (light receiving element 8) for receiving light, a reflecting surface 3a having a transparent layer 3b formed on the surface, and an incident light reflection for reflecting laser light LL emitted from the light emitting part (light emitting element 2) to the outside. Reflection member (measurement light reflection region 3d) that reflects the measurement light RL reflected by the external object toward the light receiving unit (light receiving element 8) (Deflection member 3) and at least one of boundary portions between the incident light reflection part (incident light reflection area 3c) and the measurement light reflection part (measurement light reflection area 3d) on the surface of the reflection member (deflection member 3) The light-shielding part 17 provided in the part Eteiru.

  According to the above configuration, the laser light emitted from the light emitting part toward the reflecting member is deflected by the incident light reflecting part of the incident light reflecting part of the reflecting member and emitted to the outside. The laser beam emitted to the outside is reflected by an external object. This reflected light is reflected by the measuring light reflecting portion of the deflecting member, and is detected by the light receiving portion as measuring light.

  In such a configuration, when part of the laser light emitted from the light emitting unit and incident on the incident light reflecting unit enters the inside of the transparent layer, the invading light is reflected between the deflection surface (reflection surface) and the surface of the transparent layer. After a plurality of times of reflection, the light is finally emitted to the outside of the deflecting member from a position (measurement light reflecting portion) deviated from the originally intended portion. The light thus emitted becomes light that is not originally intended, that is, “stray light”.

  According to said structure, the light-shielding part is provided in at least one part of the boundary part of an incident light reflection part and a measurement light reflection part in the surface of a reflection member. That is, the light shielding portion is formed at the boundary between the incident light reflecting portion and the measuring light reflecting portion where stray light is likely to be generated by the reflecting member. Thereby, even if a part of the laser light incident on the incident light reflecting part enters the inside of the transparent layer and stray light is generated from the reflecting member, the stray light is shielded by the light shielding part. Therefore, it is possible to reduce the generation of stray light due to the oozing of the light to the measurement light reflecting portion.

  Therefore, in the laser distance measuring device using the reflecting member having the transparent layer formed on the surface, it is possible to reduce the stray light generated by the reflecting member and provide a laser distance measuring device with high measurement accuracy.

  In the laser distance measuring device (ranging device 1, 1a) according to aspect 2 of the present invention, in the above aspect 1, the transparent layer 3b may be made of a dielectric multilayer film.

  According to said structure, the transparent layer is formed from the dielectric multilayer film with a high reflectance. Therefore, the reflectance of the reflecting member can be increased and a more accurate laser distance measuring device can be provided.

  The laser distance measuring device (ranging device 1, 1a) according to aspect 3 of the present invention is the above-described aspect 1 or 2, wherein the laser light LL emitted from the light emitting unit (light emitting element 2) is converted into the incident light reflecting unit. It may be configured to include an optical path member (laser light passage member 9) in which an optical path 9a to be incident on (incident light reflection region 3c) is formed.

  According to said structure, the optical path member in which the optical path which makes the laser beam radiate | emitted from the light emission part inject into the incident light reflection part of a reflection member was formed is provided. Thereby, since the incident position of the laser beam emitted from the light emitting unit is defined by the optical path, the laser beam enters the incident light reflecting unit of the reflecting member and does not enter the measuring light reflecting unit. For this reason, the laser beam incident on the incident light reflecting portion and the measurement light incident on the measuring light reflecting portion are separated. Therefore, it is possible to reduce the laser light emitted from the light emitting unit from entering the measurement light reflecting unit of the reflecting member and being received as stray light by the light receiving unit.

  In the laser distance measuring device (ranging device 1, 1a) according to aspect 4 of the present invention, in the above aspect 3, the optical path member (laser light passage member 9) is emitted from the light emitting unit (light emitting element 2). The optical path 9a for allowing the laser light LL to be incident on the incident light reflecting portion (incident light reflecting region 3c) may be formed with a hole through which the laser light LL passes.

  According to said structure, the optical path of the optical path member is formed from the hole part which lets a laser beam pass. Thereby, the laser light emitted from the light emitting part can pass through this hole part and be surely incident on the incident light reflecting part.

  The laser distance measuring device (ranging device 1, 1 a) according to aspect 5 of the present invention is the reflection member (laser beam LL emitted from the light emitting part (light emitting element 2) through the hole in the aspect 4. The incident area to the deflecting member 3) may be limited to the incident light reflecting portion (incident light reflecting area 3c).

  According to said structure, the incident area | region of the laser beam radiate | emitted from the light emission part is restrict | limited to an incident light reflection part by the hole formed in the optical path member. Therefore, the light incident on the incident light reflecting portion and the light incident on the measuring light reflecting portion can be separated.

  The laser distance measuring device (ranging device 1, 1a) according to aspect 6 of the present invention is the above aspect 3-5, wherein the optical path 9a formed in the optical path member (laser light passage member 9) is the reflection member ( The surface of the deflecting member 3) has a contact portion that comes into contact with the outer edge portion of the incident light reflecting portion (incident light reflecting region 3c), and the light shielding portion 17 is formed on at least a part of the outer peripheral portion of the contact portion. May be.

  According to said structure, since the optical path formed in the optical path member has the contact part which contacts the outer edge part of an incident light reflection part directly, a clearance gap is not formed between an optical path member and a reflection member. As a result, the laser light emitted from the light emitting portion is reliably incident on the incident light reflecting portion of the reflecting member. For this reason, the laser light incident on the incident light reflecting portion and the measuring light incident on the measuring light reflecting portion are completely separated. Furthermore, the light shielding part is formed on at least a part of the outer peripheral part of the contact part. Therefore, the generation of stray light due to the oozing of light to the measurement light reflecting portion can be more reliably reduced.

  The laser distance measuring device (ranging device 1, 1 a) according to aspect 7 of the present invention is the above aspect 6, wherein the light shielding portion 17 is an incident light reflecting portion (incident light) on the surface of the reflecting member (deflecting member 3). It may be made of a light-shielding adhesive that adheres the optical path member (deflection member 3) to the outer edge of the reflection region 3c).

  According to said structure, since the light-shielding part is formed from the light-shielding adhesive, the light-shielding part has a function of shielding stray light from the reflecting member and a function of adhering the reflecting member and the optical path member. Moreover, adhesion | attachment of a reflection member and an optical path member, and formation of a light-shielding part can be implemented simultaneously. Therefore, the configuration and manufacturing process of the laser distance measuring device can be simplified.

  The laser distance measuring device (ranging device 1, 1 a) according to aspect 8 of the present invention is the above-described aspect 1 to 6, wherein the light shielding part 17 is made of a light shielding paint on the surface of the reflecting member (deflection member 3). It may be applied to the part.

  According to said structure, a light shielding part can be formed by the simple process of apply | coating a light-shielding coating material on the surface of a reflection member.

  A laser range finder (ranging unit 1, 1 a) according to aspect 9 of the present invention is the aspect 1 to 8, wherein the surface of the reflecting member (deflection member 3) is emitted from the light emitting part (light emitting element 2). The laser beam LL thus formed is a flat surface inclined with respect to the direction in which the incident laser beam LL enters the incident light reflecting portion (incident light reflecting region 3c). It may be formed along a region approaching the light receiving portion (light receiving element 8) from a boundary portion between the incident light reflecting portion (incident light reflecting region 3c) and the measuring light reflecting portion (measuring light reflecting region 3d).

  According to said structure, a reflection member is inclined and arrange | positioned with respect to the direction in which the laser beam radiate | emitted from the light emission part injects into an incident light reflection part. That is, the reflecting member is disposed to be inclined with respect to the light receiving unit. In this case, as the distance from the boundary between the incident light reflecting part and the measurement light reflecting part on the surface of the reflecting member approaches the light receiving element, the rate at which stray light generated by the reflecting member is detected by the light receiving part increases.

  According to said structure, a light-shielding part is formed along the area | region where the ratio by which the stray light produced by such a reflection member is detected by a light-receiving part becomes high. Accordingly, it is possible to reliably reduce detection of stray light by the light receiving unit while reducing a region where the light shielding unit is formed. Further, the region where the light shielding portion is not formed can be widely used as the measurement light reflecting portion. Thereby, the light detection efficiency of the measurement light by the light receiving unit can be reduced by narrowing the region of the measurement light reflection unit. Therefore, it is possible to minimize the decrease in the light detection efficiency of the measurement light while preventing the generation of stray light by the light shielding portion.

  The laser distance measuring device (ranging device 1a) according to aspect 10 of the present invention is the light transmission for transmitting the laser light LL emitted to the outside by the reflecting member (deflection member 3) in the above aspects 1 to 9. Part 6 and a light shielding member 18 that shields stray light STL2 generated when a part of the laser beam LL is reflected by the light transmissive part 6, and the light shielding member 18 faces the light transmissive part 6. You may have the cylindrical recessed part which opens.

  According to the above configuration, the stray light generated when a part of the laser light is reflected by the light transmitting portion is incident on the cylindrical recess that opens to face the light transmitting portion. Can be shielded.

  The present invention can be used in a laser radar apparatus that measures a distance by scanning a laser beam.

1 Rangefinder (Laser rangefinder)
2 Light emitting element (light emitting part)
3 Deflection member (reflective member)
3a Reflecting surface 3b Transparent layer 3c Incident light reflecting region (incident light reflecting portion)
3d Measurement light reflection area (measurement light reflection part)
6 Light transmission part 8 Light receiving element (light receiving part)
9 Laser beam passage member (optical path member)
9a Optical path (hole through which laser light passes)
17 light shielding part 18 light shielding member STL stray light STL2 stray light LL laser light RL measurement light

Claims (7)

A light emitting unit for emitting laser light;
A light receiving unit for receiving measurement light reflected by an external object from the laser beam;
A reflective surface having a transparent layer formed on the surface, an incident light reflecting part for reflecting laser light emitted from the light emitting part toward the outside, and a measuring light reflected by the external object toward the light receiving part A reflecting member having a measurement light reflecting portion to be reflected;
A light-shielding portion provided on at least a part of the boundary between the incident light reflecting portion and the measurement light reflecting portion on the surface of the reflecting member ;
An optical path member formed with an optical path for allowing the laser light emitted from the light emitting section to enter the incident light reflecting section;
The optical path formed in the optical path member has a contact portion that contacts the outer edge portion of the incident light reflecting portion on the surface of the reflective member,
The light shielding part is formed on at least a part of an outer peripheral part of the contact part, and shields stray light generated when a part of the laser light incident on the reflecting member enters the transparent layer. Laser distance measuring device.   The laser distance measuring device according to claim 1, wherein the transparent layer is made of a dielectric multilayer film. The optical path member, wherein the laser light emitted from the light emitting unit as an optical path to be incident on the incident light reflecting portion, to claim 1 or 2, characterized in that holes for passing the laser beam is formed Laser ranging device. The laser range finder according to claim 3 , wherein an incident area of the laser beam emitted from the light emitting unit through the hole to the reflecting member is limited to the incident light reflecting unit. 5. The laser according to claim 1, wherein the light shielding portion is made of a light shielding adhesive that adheres the optical path member to an outer edge portion of the incident light reflecting portion on the surface of the reflecting member. Distance measuring device. The light blocking portion, a laser distance measuring apparatus according to any one of claims 1 to 4, characterized in that light-shielding coating is formed by coating a part of the surface of the reflecting member. The surface of the reflecting member is a flat surface inclined with respect to the direction in which the laser light emitted from the light emitting unit is incident on the incident light reflecting unit,
The light shielding part, according to claim 1-6, characterized in that it is formed along a region closer to the light receiving portion from a boundary portion of the said incident light reflection portion on the surface of the reflecting member and the measuring beam reflected portion The laser range finder according to any one of the above.

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