JP5663251B2 - Beam light emitter / receiver - Google Patents

Description

  The present invention relates to a beam light projecting / receiving device, and more particularly to a beam light projecting / receiving device used in an optical distance measuring device or the like that measures a distance to an object using a light beam.

  Conventionally, in order to measure the distance to an object in the monitored region, a light beam such as a laser beam is emitted so as to scan the space in a multidimensional manner, and the light beam is emitted and then reflected from the object. There is known an optical distance measuring device configured to measure a time until light is received and measure a distance to an object. In such an optical distance measuring device, a light source unit that emits a light beam such as a laser beam, a scan mirror that reflects and scans the light beam emitted from the light source unit so as to scan the target region in a multidimensional manner, A beam light projecting / receiving device including a light receiving element that receives reflected light from the object.

  As such a beam light projecting / receiving device, what is called a coaxial type as described in Patent Document 1 is known. In this coaxial system type, the projection light path from when the laser beam emitted from the light source unit passes through the scan mirror to the target area and the reflected light reflected by the object in the space is scanned from the object. This is a type in which return optical paths from the mirror to the light receiving element overlap each other halfway.

  In Patent Document 1, return light reflected in the same direction as the incident direction of laser light applied to an object in a target region is reflected by a scan mirror, and is sent and received on the optical path of the return light reflected by the scan mirror. The separating member separates the optical path of the return light reflected by the scan mirror from the optical path of the light projecting beam from the light projecting / receiving separation member to the scan mirror so as to guide the return light to the light receiving element.

JP 2010-91763 A

  However, in the beam light projecting / receiving device described in Patent Document 1, the direction of the return light path separated from the light path of the light projecting beam is different from the direction in which the light source section is arranged. Had to be placed. In addition, since the optical path of the projection beam is separated from the optical path of the return light by using reflection and refraction by a plurality of mirrors and prisms, the number of parts increases, and the reflection of each mirror or prism is reflected. Since it is necessary to arrange and adjust the surface, there is room for improvement in terms of downsizing the light beam projector / receiver and facilitating assembly and adjustment work.

  The present invention has been made paying attention to the above-described problems, and an object thereof is to provide a beam light projecting / receiving device capable of further downsizing the apparatus and facilitating assembly and adjustment work.

Therefore, the beam light projecting / receiving device according to the first aspect of the present invention includes a scan mirror that reflects and scans the light projection beam of the light source, and a light receiving element that receives the return light reflected by the object and reflected by the scan mirror. Provided with a reflection surface for reflecting one of the projected beam and the return light and a region for transmitting the other on the outer surface, and a reflection surface for reflecting the other transmitted light. A light projecting / receiving separation member formed by a prism separates the light path of the light projecting beam from the light source and the light path of the return light .

In such a configuration, a region serving as a reflection surface that reflects the light beam and a region that transmits the light beam are provided on the outer surface, and a single prism provided with a reflection surface that reflects the transmitted light beam is directed to the scan mirror. the optical path of the projected beam, comprising an optical path of the return light reflected by the scan mirror is reflected by the object body to be separated from each other.

According to a second aspect of the present invention , there is provided a beam light projecting / receiving device according to the present invention , comprising: a scan mirror that reflects and scans the light projection beam of the light source; and a light receiving element that receives the return light reflected by the object and reflected by the scan mirror. And an outer surface of the prism which is provided with a region serving as an outer reflecting surface that reflects one of the projection beam and the return light, and a region that transmits the other, and the other of the transmitted light. A light projecting / receiving separation member formed by providing an inner reflection surface for reflecting light separates the light path of the light projecting beam from the light source and the light path of the return light .

In such a configuration, light is projected on either the outer reflecting surface provided on the outer surface of the prism or the inner reflecting surface that reflects the light beam transmitted through the light transmitting region provided on the outer surface of the prism. reflects the beam to the scan mirror direction, on the other reflecting surface, by reflecting the return light from the scan mirror to the light receiving element direction, and the optical path of the projected beam of light toward the scan mirror at scan mirror is reflected by the object body The optical path of the reflected return light is separated from each other.

According to the beam light projecting / receiving device of the present invention described in claim 1, the outer surface is provided with a region serving as a reflection surface that reflects one of the light projecting beam and the return light and a region transmitting the other. The projecting / receiving separation member formed by a single prism provided with a reflecting surface for reflecting the other transmitted light separates the light path of the light projecting beam and the light path of the return light, so that the return light is reflected. If the reflecting surface to be formed is formed so that the reflection direction is the same direction as the light source, the light source and the light receiving element can be arranged side by side, and the beam light projecting and receiving device can be downsized. Further, since the optical path of the projection beam and the optical path of the return light are separated by one prism, the number of parts can be reduced as compared with the conventional apparatus, and the apparatus can be downsized and the assembly adjustment work can be facilitated.

According to the beam light projecting / receiving device of the present invention described in claim 2, the light beam projecting / receiving device is constituted by at least one prism, and the outer surface of the prism becomes an outer reflecting surface for reflecting either the light projecting beam or the return light. A light projecting / receiving separation member formed by providing a region and a region that transmits the other and an inner reflection surface that reflects the other transmitted light separates the light path of the light projecting beam and the light path of the return light. Since the outer reflection surface or inner reflection surface that reflects the return light is formed so that the reflection direction is the same direction as the light source, the light source and the light receiving element can be arranged side by side, and the beam light projection The light receiving device can be downsized. Also, by separating the optical path of the projection beam and the optical path of the return light by using the outer reflection surface and the inner reflection surface of the prism, the number of parts can be reduced as compared with the conventional device, and the assembly adjustment work can be facilitated. .

It is a block diagram which shows schematic structure of the optical ranging apparatus to which the beam light projector / receiver of this invention is applied. It is a schematic block diagram which shows 1st Embodiment of the beam light projector / receiver of this invention. It is a perspective view of the light projection / reception separation member (prism) in 1st Embodiment. It is a figure for demonstrating the example of the optical axis adjustment by a corner cube. It is a schematic block diagram which shows 2nd Embodiment of the beam light projector / receiver of this invention. It is a schematic block diagram which shows 3rd Embodiment of the beam light projector / receiver of this invention. It is a perspective view of the light projection / reception separation member (prism) in 3rd Embodiment. It is a perspective view of the modification of the light projection / reception separation member (prism) in 3rd Embodiment. It is a schematic block diagram which shows 4th Embodiment of the beam light projector / receiver of this invention. It is a perspective view of the light projection / reception separation member (prism) in 4th Embodiment. It is a schematic block diagram which shows 5th Embodiment of the beam light projector / receiver of this invention. It is a perspective view of the light projection / reception separation member (prism) in 5th Embodiment.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
First, before explaining the details of the beam projection / reception apparatus of the present invention, an optical distance measuring apparatus will be described as an application example of the beam projection / reception apparatus of the present invention.
FIG. 1 is a block diagram showing a schematic configuration of the optical distance measuring device.
In FIG. 1, an optical distance measuring device 1 measures (measures) a distance to an object existing in the target region by performing a Lissajous scan or a raster scan with a projection beam (laser pulse) in the target region. A distance image based on the measurement result is generated and output (displayed).

  The optical distance measuring device 1 is configured to be operable in, for example, a plurality of operation modes. As shown in FIG. 1, the information input unit 3, an electromagnetically driven scan mirror 5, and a drive for driving the scan mirror 5. The light source unit 9 that emits the projection light beam, the light projecting / receiving separation member 11 that separates the optical path of the emitted light projection beam and the reflected light (return light), and the light projection beam. A light receiving unit 13 that receives reflected light (return light), a distance measuring unit 15 that measures a distance to an object that reflects the projected beam, and an image generator that generates a distance image based on the measurement result of the distance measuring unit 15 And a display unit 19 that outputs (displays) the generated distance image. The beam light projector / receiver of the present invention to be described later is applied to a beam light projector / receiver configured to include the light source unit 9, the scan mirror 5, the light projecting / receiving separation member 11 and the light receiving unit 13.

  For example, the user inputs information related to the operation of the optical distance measuring device 1, for example, a mode selection command for selecting an operation mode of the optical distance measuring device 1 to the information input unit 3. Selectable operation modes include, for example, the basic “normal measurement mode”, “detailed measurement mode” that increases the number of measurement positions compared to the normal measurement mode, and performs detailed distance measurement on the target area, and part of the target area There are a “partial detail mode” for performing detailed distance measurement and a “high-speed measurement mode” for which the distance measurement completion time for the target area is shorter than that in the normal measurement mode.

  The scan mirror 5 is formed so that a movable part having a mirror can swing in two directions orthogonal to each other, and a projection beam (pulsed light) incident on the mirror surface is two-dimensionally scanned in a spatial region. Specifically, Lissajous scanning or raster scanning is possible. As such a scan mirror 5, for example, a two-dimensional scanning semiconductor galvanometer mirror (hereinafter simply referred to as “two-dimensional galvanometer mirror”) described in Japanese Patent No. 2722314 proposed by the present applicant can be used. . This two-dimensional galvanometer mirror has two movable parts (according to each current (alternating current) flowing through two drive coils (inner drive coil and outer drive coil) and a static magnetic field generated by one or two pairs of permanent magnets). Lorentz force acts on the outer movable portion and the inner movable portion, and as a result, the inner movable portion swings in a two-dimensional direction. As the inner movable portion swings, the light projection beam incident on the mirror surface is subjected to Lissajous scanning or raster scanning within the target region. Note that two one-dimensional galvanometer mirrors are used as scan mirrors for realizing Lissajous scanning or raster scanning, and the two one-dimensional galvanometer mirrors are arranged so that the movable parts having the respective mirrors swing in directions orthogonal to each other. By doing so, Lissajous scanning or raster scanning may be performed.

  The drive unit 7 supplies a drive signal (alternating current) to the scan mirror 5 to drive the inner movable unit (and the outer movable unit) to swing. The drive unit 7 includes a drive circuit 71 that supplies a drive signal to the inner drive coil and a drive signal to the outer drive coil, a phase difference changing unit 72 that changes a phase difference between the two drive signals, and two drive signals. An amplitude changing unit 73 that adjusts the amplitude (amplitude) of the inner movable unit to change the swing amplitude of the inner movable unit.

  The driving circuit 71 inputs the phase difference from the phase difference changing unit 72 and the magnitude of each driving signal from the amplitude changing unit 73, and inputs the driving signal of the inputted magnitude to the scan mirror 5 by the phase difference inputted. Supply. Here, the frequency of each drive signal is set to a frequency that is the same as or close to the resonance frequency of the two-dimensional galvanometer mirror.

  The phase difference changing unit 72 sets the phase difference between the two drive signals in accordance with the mode selection command input via the information input unit 3, and outputs the set phase difference to the drive circuit 71.

  The amplitude changing unit 73 adjusts the magnitude (amplitude) of each drive signal to change the swing amplitude of the inner movable part of the scan mirror 5. Specifically, the amplitude changing unit 73 sets the magnitude of each drive signal according to the mode selection command input via the information input unit 3, and outputs the set magnitude to the drive circuit 71. If the oscillation amplitude of the inner movable portion is reduced, the Lissajous scanning or raster scanning range by the scan mirror 5 is reduced, and if the oscillation amplitude of the inner movable portion is increased, the Lissajous scanning or raster scanning range by the scan mirror 5 is increased. Become.

  The light source unit 9 emits a light projection beam toward a mirror formed on the inner movable portion of the scan mirror 5, and includes a light source 91, a light source control unit 92 that controls driving of the light source 91, and light projection optics. A system 93.

  The light source 91 is, for example, a semiconductor laser, and emits laser light as a projection beam by emitting light according to a drive signal from the light source control unit 92.

  The light source control unit 92 controls the light emission timing of the light source 91, that is, the emission timing of the light projection beam in accordance with the mode selection command input via the information input unit 3. The light source control unit 92 includes a light emission timing table in which, for example, a measurement position in the target region and time (timing) are associated with each operation mode, and at a timing (measurement position) set in advance according to the operation mode. The light source 91 is caused to emit light.

  The light projecting optical system 93 makes the light projecting beam emitted from the light source 91 a preferable state, and converts the light projecting beam emitted from the light source 91 into parallel light.

  The light projecting / receiving separation member 11 reflects the light projecting beam emitted from the light source 91 in the direction of the scan mirror 5 and reflects the return light reflected by the object in the target region and reflected by the scan mirror 5 in the direction of the light receiving unit 13. The optical path of the projection beam toward the scan mirror 5 and the optical path of the return light reflected by the scan mirror 5 are separated from each other.

  The light projecting beam emitted from the light source unit 9 is reflected by the light projecting / receiving separation member 11 in the direction of the scan mirror 5, reflected by the mirror of the scan mirror 5, and projected into the target region, and Lissajous scanning or raster scanning. Is done.

  The light receiving unit 13 receives and detects reflected light (returned light) emitted from the light source unit 9 and reflected by an object existing in the target region, and includes a light receiving optical system 131, a light receiving element 132, including.

  The light receiving optical system 131 focuses the reflected light (returned light) reflected by the object existing in the target region and separated from the light projection beam by the light projecting / receiving separation member 11 on the light receiving element 132.

  The light receiving element 132 receives reflected light (returned light) reflected by an object existing in the target region via the light receiving optical system 131, and for example, a photo sensor can be used.

  The distance measuring unit 15 inputs the emission timing of the light projection beam from the light source unit 9 and the light reception timing of the reflected light (return light) from the light receiving unit 13, and projects light based on the time difference between them (light flight time). Measure the distance to the object that reflected the beam. The distance measurement by the distance measurement unit 15 is performed at each measurement position in the target area, that is, every time the projection beam is emitted from the light source unit 9, and the measurement result is output to the image generation unit 17.

  The image generation unit 17 determines a pixel value at each measurement position based on the distance measured by the distance measurement unit 15 and generates a distance image for the target region. The generated distance image is, for example, an image having a different color for each measured distance, that is, a three-dimensional image in which the depth distance of an object existing in the target region is reflected. The distance image generated by the image generation unit 17 is output to the display unit 19. The display unit 19 includes a display and displays the distance image output from the image generation unit 17. The distance image can recognize an object existing in the target area, as well as a change in the position of the object, the distance to the object, the posture of the object, and the like.

Next, the light beam projecting / receiving device according to the present invention applied to the above-described optical distance measuring device will be described.
2 and 3 show a first embodiment of a beam light projecting / receiving device according to the present invention.
FIG. 2 is a schematic configuration diagram of the beam light projecting / receiving device according to the present embodiment. The beam light projecting / receiving device 200 according to the present embodiment includes, for example, a light source 210 that emits laser light as a light projecting beam with a semiconductor laser, and a light source separating the benzalkonium Li formate lens 220 converts the light projection beam into parallel light from 210, the optical path of the reflected light from the object light path and the target area of projected beam emitted from the light source 210 (returning light) The light projecting / receiving separation member 230, the scan mirror 240, the condensing lens 250 for condensing the return light separated from the light projection beam by the light projecting / receiving separation member 230, and the return condensed on the light receiving surface by the condensing lens 250. And a light receiving element 260 that receives light. Reference numeral 270 denotes a cover glass that is attached to a housing or the like in front of the scan mirror to prevent or protect the scan mirror 240 when applied to an optical distance measuring device or the like. Here, the light source 210, the collimating lens 220, the light projecting / receiving separation member 230, the scan mirror 240, the condensing lens 250, and the light receiving element 260 are the light source 91 of the light source unit 9 and the light projecting optics in the optical distance measuring device 1 of FIG. This corresponds to the system 93, the light projecting / receiving separation member 11, the scan mirror 5, the light receiving optical system 131 of the light receiving unit 13, and the light receiving element 132, respectively.

  The light projecting / receiving separation member 230 has a reflecting surface that reflects the light projecting beam emitted from the light source 210 and converted into parallel light by the collimator lens 220 toward the scan mirror 240, and is projected by an object in the target region. An optical path of a light projecting beam toward the scan mirror 240 (shown by a solid line in FIG. 2) has a reflection surface that reflects the reflected light (returned light) reflected in the beam incident direction and reflected by the scan mirror 240 toward the light receiving element 260. And the optical path of the return light reflected by the object in the target area and reflected by the scan mirror 240 (indicated by a dotted line in FIG. 2) are separated from each other.

  Specifically, as shown in FIG. 3, the light projecting / receiving separation member 230 is formed of, for example, one pentagonal prism having five surfaces A to E. In the prism 230, for example, a reflection area 231 that reflects the projection beam in the direction of the scan mirror 240 and a transmission area 232 that transmits the return light (reflection light) are formed on the A surface, which is one of the outer surfaces. . The reflection region 231 is a mirror-reflecting surface so that the projected beam is reflected approximately 100%, and is coated so that scattered light or the like is not generated, and becomes an outer reflecting surface. The transmissive region 232 is provided with a non-reflective coating so that almost 100% of the return light is transmitted. The prism 230 is formed so that the return light transmitted through the transmission region 232 is reflected in the direction of the light receiving element 260 on the D surface inside the prism 230. At this time, the return light reflected from the D surface, transmitted through the B surface, and directed to the light receiving element 260 is parallel to the light projection beam from the light source 210 to the scan mirror 240 via the collimator lens 220. The angle of the D surface with respect to the B surface is determined.

  In the present embodiment, the reflection region 231 (outer reflection surface) is a reflection surface that reflects the projection beam emitted from the light source 210 and converted into parallel light by the collimator lens 220 toward the scan mirror 240, and the D surface. Is a reflecting surface that reflects the return light reflected by the object in the target region in the incident direction of the projection beam and reflected by the scan mirror 240 toward the light receiving element 260.

  In such a beam projection / reception device, the projection beam emitted from the light source 210 is converted into parallel light by the collimator lens 220 as shown by a solid line in FIG. 2, and is reflected by the reflection region 231 (outer reflection surface) of the prism 230. Reflected in the direction of the scan mirror 240. Further, the light is reflected by the scan mirror 240, passes through the cover glass 270, is projected onto the target area outside the apparatus, and is scanned within the target area by the swinging operation of the scan mirror 240. The return light reflected in the direction of the light projecting beam by the object existing in the target region passes through the cover glass 270 so as to be coaxial with the optical path of the light projecting beam, that is, substantially overlap, as shown by a dotted line in FIG. The light is reflected by the scan mirror 240, travels toward the A surface of the prism 230, and passes through the transmission region 232 on the A surface of the prism 230. The return light is transmitted through the transmission area 232 on the A surface of the prism 230, so that the optical path of the projection beam and the return light are separated. The return light separated from the projection beam travels through the prism 230, is reflected by the D surface (inner reflection surface) toward the light receiving element 260, passes through the B surface of the prism 230, and passes through the condenser lens 250. The light is condensed and received by the light receiving element 260.

  According to the beam light projecting / receiving device of the present embodiment, the outer reflection surface (reflection region 231) for reflecting the projection beam in the direction of the scan mirror 240 is formed on the A surface which is the outer surface of the prism 230, and the same A surface. A transmission region 232 for transmitting the return light is formed, and the D surface facing the A surface is used as an inner reflection surface so that the transmitted return light is reflected in the direction of the light receiving element 260, so that the optical path of the light projection beam Since the optical path of the return light is separated by one prism 230, the number of parts of the beam light projecting / receiving device can be reduced, and the number of adjustment parts for adjusting the optical axis of the projecting / receiving light can be reduced. And easy adjustment work. Further, on the D surface of the prism 230, the reflection direction is the same direction as the light source 210, and the light projecting beam from the light source 210 toward the prism 230 and the return light from the prism 230 toward the light receiving element 260 are parallel. If formed in this manner, the light source 210 and the light receiving element 260 can be arranged side by side, so that the size of the entire apparatus can be further reduced.

  If the arrangement and shape of the optical members such as the light source 210, the prism 230, the scan mirror 240, and the light receiving element 260 are determined, the assembly adjustment process can be greatly reduced using a retroreflective device such as a corner cube. For example, first, the light source 210 and the light receiving element 260 are arranged side by side without the prism 230 and the scan mirror 240. Then, as shown in FIG. 4, the corner cube 300 is placed in the projection direction of the projection beam, the projection beam is projected toward the corner cube 300, and the reflected light from the corner cube 300 can be received by the light receiving element 260. Thus, the arrangement of the light receiving elements 260 is adjusted. Thereby, a light projection beam and reflected light (return light) can be made substantially parallel. After that, if the prism 230 and the scan mirror 240 are set at predetermined positions, the optical axis adjustment is substantially completed, so that the assembly work process can be greatly reduced.

  In the above embodiment, the light projection beam is reflected by the reflection region 231 (outer reflection surface) and the return light is reflected by the D surface (inner reflection surface) of the prism 230, but the second embodiment shown in FIG. Conversely, the projection beam is reflected by the D surface (inner reflection surface) of the prism 230 in the direction of the scan mirror 240, and the return light is reflected by the reflection region 231 (outer reflection surface) in the direction of the light receiving element 260. A configuration may be adopted. In the case of the second embodiment having such a configuration, the same effect as that of the first embodiment can be obtained. In FIG. 5, the same elements as those in the first embodiment are denoted by the same reference numerals.

  However, since the inner reflection surface of the prism 230 is substantially totally reflected, return light having a signal level lower than that of the projection beam is reflected by the inner reflection surface of the prism 230 and received by the light receiving element 260. One embodiment is preferred.

6 and 7 show a third embodiment of the light beam projector / receiver according to the present invention. In addition, the same code | symbol is attached | subjected to the same element as 1st Embodiment.
FIG. 6 is a schematic configuration diagram of the light beam projecting / receiving device according to the present embodiment. The light beam projecting / receiving device 200 according to the present embodiment has a rectangular shape as shown in FIG. A reflection region 231 having a shape is formed, and a transmission region 232 is formed in a portion excluding the reflection region 231 on the A surface. The shape of the reflection region 231 may be a circular shape as shown in FIG.

  According to the third embodiment, in addition to the same effects as in the first embodiment, the area of the transmission region 232 increases, so that the inner reflection surface (D surface) inside the prism 230 is reflected toward the light receiving element 260. The amount of return light can be increased.

9 and 10 show a fourth embodiment of the beam light projecting and receiving apparatus according to the present invention. In addition, the same code | symbol is attached | subjected to the same element as 1st Embodiment.
FIG. 9 is a schematic configuration diagram of the light beam projecting / receiving device 200 according to the present embodiment. The light beam projecting / receiving device 200 according to the present embodiment has a reflection region 231 and a transmission region 232 on two surfaces of the outer surface of the prism 230. They are formed separately. That is, as shown in FIG. 10, a new surface F is formed on the prism 230 to have a hexagonal shape, the reflective region 231 (outer reflective surface) is formed on the A surface, and the transmissive region 232 is formed on the adjacent F surface. Then, the return light transmitted through the transmission region 232 on the F surface is reflected toward the light receiving element 260 by the D surface which is the inner reflection surface of the prism 230.

  According to the fourth embodiment, since the reflection region 231 of the projection beam and the transmission region 232 of the return light are on different surfaces, the projection beam whose signal level is significantly higher than that of the return light is transmitted through the transmission region 232. Therefore, it is difficult for the return light to leak to the optical path side, so that the isolation characteristics of light projection / light reception can be improved.

  In the case of each configuration of the third embodiment in FIG. 6 and the fourth embodiment in FIG. 9, the light projection beam is reflected on the inner reflection surface (D surface) of the prism 230 as in the second embodiment in FIG. 5. A configuration may be adopted in which the reflected light is reflected in the direction of the scan mirror 240 and the return light is reflected in the direction of the light receiving element 260 by the reflection region 231 (outside reflection surface). 6 and FIG. 9 are preferable.

11 and 12 show a fifth embodiment of the light beam projecting / receiving device according to the present invention. In addition, the same code | symbol is attached | subjected to the same element as 1st Embodiment.
FIG. 11 is a schematic configuration diagram showing a fifth embodiment of the beam projection / reception apparatus according to the present embodiment. The beam projection / reception apparatus 200 according to the present embodiment includes a prism 230 shown in FIG. Further, another prism 330 having a transmission region 332 that transmits the return light from the scan mirror 240 and an inner reflection surface (D1 surface) that reflects the return light transmitted in the direction of the light receiving element 260 is combined. It is a thing. That is, as shown in FIG. 12, the prism 330 has a pentagonal shape having five surfaces B1 to E1 and G1, and when the prism 330 is coupled to the prism 230 as shown in FIG. The surfaces E1 to E1 are formed so as to be flush with the surfaces B to E of the prism 230, and the G1 surface is formed to have a step difference from the F surface of the prism 230. Then, a non-reflective coating is applied to form a transmission region 332 through which the return light is transmitted, and the return light transmitted through the transmission region 332 is reflected in the prism 330 toward the light receiving element 260 with the D1 surface as an inner reflection surface. To form.

According to the fifth embodiment, similar to the fourth embodiment, since the reflection region 231 of the projection beam and the transmission regions 232 and 332 of the return light are on different surfaces, the signal level is much higher than that of the return light. A high light projection beam hardly leaks to the optical path side of the return light transmitted through the transmission region 232, and the isolation characteristics of light projection / light reception can be improved. In addition, since the area of the transmissive region increases, the amount of return light reflected toward the light receiving element 260 increases, and the amount of light received by the light receiving element 260 can be increased.

In each of the above-described embodiments, an appropriate convex shape or concave shape is provided on each of the A surface, the B surface, the D surface of the prism 230 and the D1 surface of the prism 330 located in the middle of the optical path of the projection beam and the optical path of the return light. With this curvature, it is possible to omit the collimating lens 220 on the light source 210 side and the condensing lens 250 on the light receiving element 260 side, thereby further reducing the number of components and adjusting the optical axis. The optical axis adjustment work can be further facilitated by reducing the number of parts.

  The beam light projecting / receiving device of the present invention is not only an optical distance measuring device, but also any device that detects the presence, position, size, etc. of an object by irradiating a light beam and receiving return light from the object. Needless to say, the present invention can be applied as a coaxial light beam projecting / receiving device.

DESCRIPTION OF SYMBOLS 1 Optical ranging device 200 Beam light projector / receiver 210 Light source 230, 330 Prism (projection / reception separation member)
231 Reflection area (outer reflection surface)
232, 332 Transmission region D, D1 Inner reflection surface 240 Scan mirror 260 Light receiving element

Claims (11)

A scan mirror that reflects and scans the light projecting beam of the light source and a light receiving element that receives the return light reflected by the object and reflected by the scan mirror, and becomes a reflection surface that reflects either the light projection beam or the return light A light projecting / receiving separation member formed of one prism provided with a reflecting surface for reflecting the other light transmitted through the outer surface and a region that transmits the other light, and returns to the light path of the light projecting beam of the light source Beam light projector / receiver that separates the optical path of light. A scan mirror that reflects and scans the light projection beam of the light source and a light receiving element that receives the return light reflected by the object and reflected by the scan mirror, and is composed of at least one prism, and the light projection beam is formed on the outer surface of the prism. A light projecting / receiving separation member formed by providing an outer reflection surface that reflects one of the return light and a region that transmits the other, and an inner reflection surface that reflects the other transmitted light, A beam light projecting / receiving device that separates an optical path of a light projecting beam from a light source and an optical path of return light.   The prism has a light beam reflection region and a light beam transmission region on the outer surface, and a reflection surface for reflecting the light beam transmitted through the transmission region inside the prism, and the reflection on the outer surface. The region is defined as an outer reflecting surface, the reflecting surface that reflects the transmitted light beam inside the prism is defined as an inner reflecting surface, and the projected beam is scanned by either the outer reflecting surface or the inner reflecting surface. The beam light projecting / receiving device according to claim 1, wherein the light reflecting / receiving device is configured to reflect in the direction and reflect the return light from the scan mirror toward the light receiving element by the other reflecting surface. The outer reflection surface and the inner reflection surface of the prism are formed so that a light projecting light path of a light projecting beam from the light source to the prism and a return light path of the return light from the prism to the light receiving element are substantially parallel to each other. The beam light projector / receiver according to claim 3 .   The beam light projecting / receiving device according to claim 3 or 4, wherein the reflection region and the transmission region are formed on the same surface of the outer surface of the prism.   6. The beam light projecting / receiving device according to claim 5, wherein the reflection region is formed in a substantially central portion of the same surface, and the transmission region is formed in a portion excluding the reflection region.   The beam light projecting / receiving device according to claim 6, wherein the reflection region has a circular shape.   The beam light projector / receiver according to claim 3 or 4, wherein the reflection region and the transmission region are formed by dividing the reflection region and the transmission region into two surfaces of an outer surface of the prism.   The light projecting / receiving separation member is configured by combining a prism having the outer reflection surface and the inner reflection surface with another prism provided with a reflection surface that reflects the return light from the scan mirror toward the light receiving element. The beam light projector / receiver according to claim 2.   The light projecting / receiving separation member has a reflection region serving as an outer reflection surface that reflects the projection beam in the direction of the scan mirror on the outer surface and a transmission region that transmits the return light from the scan mirror, and transmitted through the transmission region. A prism having an inner reflection surface that reflects the return light in the direction of the light receiving element inside the prism, a transmission region that has a step with the transmission region and transmits the return light from the scan mirror, and the return light that has passed through the transmission region. The beam light projecting / receiving device according to claim 9, wherein another prism having an inner reflection surface that reflects toward the light receiving element inside the prism is coupled.   The optical distance measuring device according to any one of claims 1 to 10, wherein the optical distance measuring device is configured to measure a distance to an object in the target region based on an emission timing of a light projection beam from the light source and a light reception timing of return light from the light receiving element. The beam light projector / receiver described in one.