JP2012226020A - Distance measuring instrument - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a distance measuring instrument capable of simultaneously measuring a plurality of visual fields.SOLUTION: The distance measuring instrument includes: a laser light source which emits measuring light; a photo detector which detects reflected light from a measurement object; an optical scanner including a first reflecting mirror, a first holding frame disposed around the first reflecting mirror, a first supporting beam pivotally supporting the first reflecting mirror so that the first reflecting mirror is rotatable around a vertical axis relative to the first holding frame, a second reflecting mirror disposed on a lower surface of the first holding frame, a third reflecting mirror disposed on an upper surface of the first holding frame, a second holding frame disposed around the first holding frame, and a second supporting beam pivotally supporting the first holding frame so that the first holding frame is rotatable around a horizontal axis relative to the second holding frame; a light guiding optical system which guides the measuring light emitted from the laser light source to the optical scanner and guides the reflected light received by the optical scanner to the photo detector; and a control unit which controls driving of the laser light source and the optical scanner and calculates a distance to the measurement object on the basis of a detection signal of the photo detector.

Description

  The present invention relates to a distance measuring device.

  Conventionally, a distance measuring device that measures a distance to a measurement object by projecting a light pulse to the measurement object and measuring a response time required from receiving the light pulse to receiving a reflected light pulse. Is used. On the other hand, an optical scanning device capable of performing two-dimensional scanning, such as a MEMS (Micro Electro Mechanical Systems) mirror in which components such as a movable mirror and an elastic beam are integrally formed using micromachining technology, and this optical scanning device Various image projection apparatuses and the like have been proposed (Patent Document 1, Patent Document 2, Non-Patent Document 1).

  Recently, a two-dimensional scanning type distance measuring device using a MEMS mirror as an optical scanning device has been proposed for a light projecting / receiving optical system for projecting / receiving light pulses (Non-patent Documents 2 and 3). For example, Non-Patent Document 2 discloses a three-dimensional distance image sensor equipped with a two-dimensional scanning mirror “ECO SCAN (registered trademark)” manufactured by Nippon Signal.

  Patent Document 3 discloses an automatic monitoring device that includes a condensing optical system using a MEMS mirror and detects the position of an object in a predetermined space. In this condensing optical system, after the laser light projected from the light source part passes through the hole part of the perforated reflection mirror, it is scanned by the scanning mirror, and the return light reflected by the object is reflected by the scanning mirror. In the perforated reflecting mirror, the light is reflected by the reflecting surface around the hole and received by the light receiving element.

JP 2010-266506 A JP 2010-266508 A JP 2004-170965 A

Wyatt O. Davis, Randy Sprague, Josh Miller, "MEMS-Based Pico Projector Display", p31-32, IEEE (2008) http://www.signal.co.jp/vbc/mems/

  However, in a conventional MEMS mirror that performs two-dimensional scanning, a single movable mirror arranged at the center is rotated (oscillated) about a vertical axis and a horizontal axis to make a single light beam into a two-dimensional shape. Scanning. When the above MEMS mirror is used as an optical scanning device of a light projecting / receiving optical system, one movable mirror is used for light projecting / receiving. The mirror area irradiated with the laser light for light projection reflects the received return light to the light source side and cannot be used as a mirror area for light reception. Therefore, when a single movable mirror is used for light projection and reception, only a single visual field is measured.

  The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a distance measuring device capable of simultaneously measuring a plurality of visual fields.

  In order to achieve the above object, the invention according to claim 1 is a laser light source that emits measurement light that is projected onto a measurement object, and a photodetector that detects reflected light reflected by the measurement object. And a first reflecting mirror, a first holding frame disposed around the first reflecting mirror, and an axis that allows the first reflecting mirror to rotate about a vertical axis with respect to the first holding frame. The first supporting beam to be supported, the second reflecting mirror disposed on one of the upper surface and the lower surface of the first holding frame, and the other of the upper surface and the lower surface of the first holding frame A third reflecting mirror, a second holding frame disposed around the first holding frame, and the first holding frame are pivotally supported around the horizontal axis with respect to the second holding frame. And a measuring beam emitted from the laser light source. The measurement light is guided to the optical scanning device so as to be applied to the first reflecting mirror and the second reflecting mirror, and is received by the first reflecting mirror and the third reflecting mirror. A light guide optical system for guiding reflected light to the photodetector, and driving and controlling each of the laser light source and the optical scanning device, and a distance to the measurement object based on a detection signal of the photodetector And a control unit for calculating the distance.

  According to a second aspect of the present invention, the photodetector includes a first light receiving element that receives the first reflected light that is received by the first reflecting mirror and guided to the photodetector. 3. The distance according to claim 1, further comprising: a second light receiving element that receives the second reflected light received by the three reflecting mirrors and guided to the photodetector, and outputs a detection signal for each light receiving element. It is a measuring device.

  The invention according to claim 3 is characterized in that the control unit performs at least one of rotation of the first reflecting mirror around the vertical axis and rotation of the first support frame around the horizontal axis. The distance measuring device according to claim 1, wherein the optical scanning device is driven and controlled.

  According to the distance measuring device of the present invention, it is possible to measure a plurality of visual fields at the same time, and there is an effect that a detailed object can be measured as compared with a conventional distance measuring device having a single visual field.

It is the schematic which shows an example of a structure of the distance measuring device which concerns on embodiment of this invention. It is a perspective view which shows the structure of the light projection / reception optical system of the distance measuring apparatus shown in FIG. FIG. 3 is a perspective view illustrating an example of a configuration of an optical scanning device of the light projecting / receiving optical system illustrated in FIG. 2. It is a top view which shows an example of the rotational vibration mechanism of the optical scanning device shown in FIG. (A)-(D) are the schematic diagrams which show the relationship between the reflective mirror for light reception, and the reflective mirror for light projection. It is a schematic diagram which shows a mode that two visual fields are simultaneously measured with the optical scanning device shown in FIG. (A) is a schematic diagram which shows a mode that two types of reflected light is received with the distance measuring device shown in FIG. 1, (B) shows the position where a light receiving element is arrange | positioned corresponding to two types of reflected light. It is sectional drawing along the optical axis shown. (A) is a perspective view showing a state of vertical axis resonance / horizontal axis non-resonance, and (B) is a schematic diagram showing how two fields of view are measured simultaneously in a state of vertical axis resonance / horizontal axis non-resonance. . (A) is a perspective view showing a state of vertical axis non-resonance / horizontal axis resonance, and (B) is a schematic diagram showing how two fields of view are measured simultaneously in a state of vertical axis non-resonance / horizontal axis resonance. . (A) is a perspective view showing a state of vertical axis resonance / horizontal axis resonance, and (B) is a schematic diagram showing how two fields of view are measured simultaneously in a state of vertical axis resonance / horizontal axis resonance.

  Hereinafter, an example of an embodiment of the present invention will be described in detail with reference to the drawings.

(Schematic configuration of the distance measuring device)
First, an example of the configuration of the distance measuring device will be described. Here, an example will be described in which the distance measuring device is configured as a laser radar device that can measure the distance to an object in a wide range using the straightness of laser light. FIG. 1 is a schematic diagram showing an example of the configuration of a distance measuring device according to an embodiment of the present invention.

  As shown in FIG. 1, the distance measuring device 10 includes a light projecting unit 20 that projects measurement light onto a measurement object (hereinafter referred to as “object”), and reflected light reflected by the measurement object. A light receiving unit 30 that receives light and a control unit 40 that performs various calculations and controls each unit of the apparatus are provided. The distance measuring device 10 includes a light projecting / receiving optical system 50 that functions as a light projecting optical system of the light projecting unit 20 and a light receiving optical system of the light receiving unit 30.

  The light projecting / receiving optical system 50 includes an optical scanning device 60 configured to be capable of two-dimensional scanning of measurement light. The control unit 40 is connected to a display input unit 42 that displays measurement results and the like and receives instruction inputs from the user. A specific configuration example of the optical scanning device 60 will be described later in detail.

  The light projecting unit 20 includes a laser light source 24 that emits measurement light, a laser driving unit 26 that drives the laser light source 24, and a scanning driving unit 28 that drives the optical scanning device 60. The laser drive unit 26 and the scan drive unit 28 are electrically connected to the control unit 40. The laser drive unit 26 drives and drives the laser light source 24 based on a control signal from the control unit 40. Further, the scanning drive unit 28 drives the optical scanning device 60 based on the control signal from the control unit 40 so that the measurement light is two-dimensionally scanned.

  As the laser light source 24, a semiconductor laser (LD) or the like can be used. For example, a semiconductor laser having an oscillation wavelength of 1.55 μm can be used. Note that the laser light source 24 normally includes a light detection unit for output monitoring. A detection signal from the built-in light detection unit is input to the control unit 40 via the laser driving unit 26 as a “measurement light output signal”.

  The light receiving unit 30 includes a photodetector 32 that detects reflected light received by the light projecting / receiving optical system 50. The photodetector 32 is electrically connected to the control unit 40. As will be described later, the photodetector 32 includes a plurality of light receiving elements 34A and 34B, and an optical signal received by each of the plurality of light receiving elements 34A and 34B is photoelectrically converted into an electric signal. The electrical signal photoelectrically converted by the photodetector 32 is input to the control unit 40 as a “reflected light detection signal”.

  As the light receiving elements 34A and 34B, photodiodes (PD) can be used. For example, when a semiconductor laser having an oscillation wavelength of 1.55 μm or the like is used as the laser light source 24, a photodiode having sensitivity to infrared rays including a wavelength of 1.55 μm can be used as the light receiving elements 34A and 34B. When it is not necessary to distinguish between the plurality of light receiving elements 34A and 34B, they are collectively referred to as the light receiving element 34.

  The control unit 40 includes an A / D converter, a storage unit such as a ROM and a RAM, and a central processing unit such as a CPU. The ROM stores programs for executing various processing routines such as calculation of the distance to the measurement object, various data, and the like. The RAM is used as a work area for performing various calculations performed by the CPU. As described above, the measurement signal output signal and the reflected light detection signal are input to the control unit 40. These analog signals input to the control unit 40 are converted into digital signals by an A / D converter (not shown) and held in a storage unit (not shown).

  The control unit 40 calculates a response time required from receiving the measurement light to receiving the reflected light based on the obtained measurement light projection timing and reflected light reception timing. Then, based on the calculated response time, the distance to the measurement object is calculated. The distance to the measurement object obtained by the calculation may be displayed on the display input unit 42 as a measurement result.

(Emitter / receiver optical system)
Next, the configuration of the light projecting / receiving optical system will be described. FIG. 2 is a perspective view showing an example of a specific configuration of the light projecting / receiving optical system 50 of the distance measuring apparatus shown in FIG. As shown in FIG. 2, the light projecting / receiving optical system 50 is configured to be capable of projecting a lens 52, a plate-shaped perforated reflector 54 having a hole 54 </ b> A, a light receiving lens 56, and two-dimensional scanning. The optical scanning device 60 is provided. The hole portion 54A is a through hole that penetrates the perforated reflector 54 in the thickness direction. As will be described later, the optical scanning device 60 includes a plurality of reflecting mirrors, and each of the plurality of reflecting mirrors rotates around at least one of the vertical axis and the horizontal axis, thereby causing two directions, a vertical direction and a horizontal direction. Scanning is possible.

  The lens 52 for light projection, the perforated reflecting mirror 54, and the optical scanning device 60 are arranged in this order from the laser light source 24 side. In FIG. 2, the optical scanning device 60 is viewed from the back side, and the reflection surface 60A of the optical scanning device 60 faces the perforated reflecting mirror 54 side. The perforated reflecting mirror 54 is disposed so that the reflecting surface 54 </ b> B faces the reflecting surface 60 </ b> A side of the optical scanning device 60. The light receiving lens 56 is disposed between the perforated reflecting mirror 54 and the photodetector 32. The photodetector 32 is disposed at the image forming position of the light receiving lens 56.

  In the light projecting / receiving optical system 50, as shown by the solid line, the measurement light emitted from the laser light source 24 is collimated by the light projecting lens 52 and passes through the hole 54A of the perforated reflecting mirror 54. Then, the light is irradiated onto the reflection surface 60 </ b> A of the optical scanning device 60. On the other hand, as shown by the dotted line, the reflected light that has been reflected and returned by the object is reflected by the reflecting surface 54B of the perforated reflecting mirror 54 in a direction away from the optical path of the measuring light. The reflected light reflected by the reflecting surface 54 </ b> B is collected by the light receiving lens 56 and detected by the photodetector 32.

(Optical scanning device)
Next, a detailed configuration of the optical scanning device 60 will be described. FIG. 3 is a perspective view showing an example of the configuration of the optical scanning device 60. In FIG. 3, the optical scanning device 60 is viewed from the front side, that is, from the reflective surface 60A side. As shown in FIG. 3, the optical scanning device 60 includes a flat plate-like first reflecting mirror 62, a first holding frame 64 disposed around the first reflecting mirror 62, and a first holding frame 64. A second holding frame 66 is provided around the periphery. The first reflecting mirror 62 is a flat reflecting mirror having a substantially rectangular shape in plan view.

  The first reflecting mirror 62 is pivotally supported by a pair of first support beams 68A and 68B so as to be rotatable around a vertical axis with respect to the first holding frame 64. The vertical axis substantially coincides with the horizontal center line of the first reflecting mirror 62. The first holding frame 64 is pivotally supported by a pair of second support beams 70A and 70B so as to be rotatable around a horizontal axis with respect to the second holding frame 66. The horizontal axis substantially coincides with the vertical center line of the first reflecting mirror 62.

  A second reflecting mirror 72 is disposed on the lower surface of the first holding frame 64. A third reflecting mirror 74 is arranged on the upper surface of the first holding frame 64. The second reflecting mirror 72 is a flat reflecting mirror having a substantially rectangular shape in plan view. The horizontal length of the second reflecting mirror 72 is longer than the horizontal length of the first reflecting mirror 62. The second reflecting mirror 72 is disposed so as to substantially cover the lower surface of the first holding frame 64.

  Similarly, the third reflecting mirror 74 is a plate-like reflecting mirror having a substantially rectangular shape in plan view, and the horizontal length of the third reflecting mirror 74 is the horizontal length of the first reflecting mirror 62. The upper holding surface 64 is disposed so as to substantially cover the upper surface of the first holding frame 64. The second reflecting mirror 72 and the third reflecting mirror 74 are formed on the surface of the first holding frame 64 by vapor-depositing a metal material having a high reflectance such as gold (Au), for example. Can do.

  Next, the mirror rotation operation (rotational vibration) of the optical scanning device 60 will be described. Hereinafter, an example in which the optical scanning device 60 is configured as an electromagnetically driven MEMS mirror will be described. FIG. 4 is a plan view showing an example of the rotational vibration mechanism of the optical scanning device 60. As shown in FIG. 4, the first reflecting mirror 62 is provided with a drive coil 76 integrally with the first reflecting mirror 62. The drive coil 76 is electrically connected to the power source 78 by, for example, a wiring 77 that passes through the first support beam 68B and the second support beam 70A. The first holding frame 64 is provided with a drive coil 80 integrally with the first holding frame 64. The drive coil 80 is electrically connected to the power source 82 by, for example, a wiring 83 that passes through the second support beam 70B.

  In addition, permanent magnets 84 </ b> A and 84 </ b> B that form a magnetic field with respect to the drive coil 76 of the first reflecting mirror 62 are provided on the upper side and the lower side of the second holding frame 66 facing each other in the vertical direction. Permanent magnets 86 </ b> A and 86 </ b> B that form a magnetic field with respect to the drive coil 80 of the first holding frame 64 are provided on the left side and the right side of the second holding frame 66 that are opposed to each other in the horizontal direction.

  For example, a magnetic field is formed in the drive coil 76 of the first reflecting mirror 62 in a direction across the drive coil 76 by the permanent magnets 84A and 84B. When a current is passed through the drive coil 76 by the power supply 78, a magnetic force that rotates the first reflecting mirror 62 around the vertical axis is generated. When the first reflecting mirror 62 rotates, the pair of first support beams 68A and 68B are twisted to generate a spring reaction force.

  The first reflecting mirror 62 rotates to a position where the magnetic force and the spring reaction force are balanced. The rotation angle (scanning angle) of the first reflecting mirror 62 changes according to the value of the current passed through the drive coil 76. Further, when the direction of the current flowing through the drive coil 76 is reversed, the direction of the magnetic force is reversed, and the first reflecting mirror 62 rotates in the opposite direction. Accordingly, the first reflecting mirror 62 is rotationally oscillated at a predetermined frequency around the vertical axis.

  Similarly, a magnetic field is formed in the drive coil 80 of the first holding frame 64 by permanent magnets 86A and 86B. When a current is passed through the drive coil 80 by the power source 82, a magnetic force that rotates the first holding frame 64 around the horizontal axis is generated. The pair of second support beams 70A and 70B are twisted to generate a spring reaction force. Thereby, the first holding frame 64 is rotationally vibrated at a predetermined frequency around the horizontal axis. That is, the first reflecting mirror 62, the second reflecting mirror 72, and the third reflecting mirror 74 are rotationally oscillated around the horizontal axis together with the first holding frame 64.

(Measurement with multiple fields of view)
Next, the principle that enables measurement in multiple fields of view will be described. FIGS. 5A to 5D are schematic views showing the relationship between the light receiving reflecting mirror and the light projecting reflecting mirror. FIG. 6 is a schematic diagram showing how two visual fields are simultaneously measured using the optical scanning device 60 shown in FIG.

  As described above, in the light projecting / receiving optical system 50, the measurement light emitted from the laser light source 24 is collimated by the light projecting lens 52, passes through the hole 54A of the perforated reflecting mirror 54, and The light is applied to the reflection surface 60A of the optical scanning device 60 (see FIG. 2). At this time, as shown in FIGS. 5A and 5C, the measurement light irradiation area 90 includes the lower half portion 62 </ b> A of the first reflecting mirror 62 and the second reflecting mirror 72. Irradiate measurement light. Each of the first reflecting mirror 62 portion 62A and the second reflecting mirror 72 is simultaneously irradiated with measurement light, and the measurement light is projected in different directions.

  As shown by the solid line in FIG. 6, assuming the projection surface 94 in the measurement light projection direction, the measurement light reflected by the portion 62 </ b> A of the first reflecting mirror 62 is projected onto the region 96 of the projection surface 94. Is done. On the other hand, the measurement light reflected by the second reflecting mirror 72 is projected onto the region 98 of the projection surface 94. The area of the second reflecting mirror 72 is larger than the area of the portion 62 </ b> A of the first reflecting mirror 62. For this reason, the measurement light reflected by the second reflecting mirror 72 is projected onto a region 98 wider than the region 96.

  Further, as described above, in the light projecting / receiving optical system 50, the reflected light that has been reflected and returned by the object is reflected by the reflecting surface 54B of the perforated reflecting mirror 54 (see FIG. 2). At this time, as shown in FIGS. 5B and 5D, the reflected light is received by a light receiving region 92 that is symmetrical to the measurement light irradiation region 90 with respect to the horizontal axis. The reflected light receiving area 92 includes an upper half portion 62 </ b> B of the first reflecting mirror 62 and a third reflecting mirror 74.

  As shown in FIGS. 5A and 5B, the reflected light corresponding to the measurement light projected by the portion 62A of the first reflecting mirror 62 is received by the portion 62B of the first reflecting mirror 62. . On the other hand, as shown in FIGS. 5C and 5D, the reflected light corresponding to the measurement light projected by the second reflecting mirror 72 is received by the third reflecting mirror 74. That is, the portion 62A and the portion 62B of the first reflecting mirror 62 constitute a pair of light projecting / receiving reflectors. At the same time, the second reflecting mirror 72 and the third reflecting mirror 74 constitute a pair of light projecting and receiving reflecting mirrors. Accordingly, measurement light emitted from one laser light source 24 and projected in different directions can be received by separate reflecting mirrors, and measurement in two fields of view is possible.

  The first reflected light reflected by the portion 62B of the first reflecting mirror 62 and the second reflected light reflected by the third reflecting mirror 74 need to be detected separately from each other. FIG. 7A is a schematic diagram showing a state in which two types of reflected light are received by the light projecting / receiving optical system 50, and FIG. 7B shows a light receiving element 34 arranged corresponding to the two types of reflected light. It is sectional drawing along the optical axis which shows the position which is.

  As indicated by the solid line, the first reflected light is reflected by the region 54C of the reflecting surface 54B of the perforated reflecting mirror 54. The reflected light reflected from the region 54C is collected by the light receiving lens 56 and received by the light receiving element 34A of the photodetector 32. Further, as indicated by the dotted line, the second reflected light is reflected by the region 54D of the reflecting surface 54B of the perforated reflecting mirror 54. The reflected light reflected by the region 54D is collected by the light receiving lens 56 and received by the light receiving element 34B of the photodetector 32.

  The lens 56 is arranged so that the reflected light reflected at the intermediate point between the region 54C and the region 54D is collected by the light receiving lens 56 and forms a focal point F on the surface of the photodetector 32. The light receiving element 34 </ b> A and the light receiving element 34 </ b> B are arranged so as to be shifted from the position of the focus F of the light receiving lens 56. The first reflected light and the second reflected light are incident on the light receiving lens 56 from a position shifted from the optical axis L. The first reflected light (solid line) focuses on the light receiving area of the light receiving element 34A, and the second reflected light (dotted line) focuses on the light receiving area of the light receiving element 34B. As described above, since the first reflected light and the second reflected light are received by the different light receiving elements 34, they can be detected separately from each other.

(Rotational vibration operation and measurement field of view)
Next, the relationship between the rotational vibration of the optical scanning device 60 and the scanning direction will be described. FIG. 8A is a perspective view showing a state of vertical axis resonance / horizontal axis non-resonance, and FIG. 8B shows a state in which two fields of view are simultaneously measured in a state of vertical axis resonance / horizontal axis non-resonance. It is a schematic diagram. As shown in FIG. 8A, in the vertical axis resonance / horizontal axis non-resonance state, the first reflecting mirror 62 rotates and vibrates around the vertical axis, and the first holding frame 64 moves around the horizontal axis. Does not vibrate.

  In the case of vertical axis resonance / horizontal axis non-resonance, as shown in FIG. 8B, the measurement light (solid line) reflected by the portion 62A of the first reflecting mirror 62 enters the region 96 of the projection plane 94. Lighted. As the first reflecting mirror 62 oscillates around the vertical axis, the measurement light is scanned in the horizontal direction as shown by the arrows. On the other hand, the measurement light (dotted line) reflected by the second reflecting mirror 72 is projected onto the region 98 of the projection surface 94.

  FIG. 9A is a perspective view showing a state of vertical axis non-resonance / horizontal axis resonance, and FIG. 9B is a state in which two fields of view are simultaneously measured in a state of vertical axis non-resonance / horizontal axis resonance. It is a schematic diagram which shows. As shown in FIG. 9A, in the vertical axis non-resonance / horizontal axis resonance state, the first reflecting mirror 62, the second reflecting mirror 72, and the third reflecting mirror 74 are in the first holding frame 64. At the same time, the first reflecting mirror 62 does not oscillate around the vertical axis.

  In the case of vertical axis non-resonance / horizontal axis resonance, as shown in FIG. 9B, the measurement light (solid line) reflected by the portion 62A of the first reflecting mirror 62 enters the region 96 of the projection plane 94. Lighted. As the first reflecting mirror 62 oscillates around the vertical axis, the measurement light is scanned in the vertical direction as shown by the arrows. On the other hand, the measurement light (dotted line) reflected by the second reflecting mirror 72 is projected onto the region 98 of the projection surface 94. As the second reflecting mirror 72 rotates and vibrates around the vertical axis, the measurement light is scanned in the vertical direction as shown by the arrows.

  FIG. 10A is a perspective view showing a state of vertical axis resonance / horizontal axis resonance, and FIG. 10B shows a state in which two fields of view are measured simultaneously in the state of vertical axis resonance / horizontal axis resonance. It is a schematic diagram. As shown in FIG. 10A, in the state of vertical axis resonance / horizontal axis resonance, the first reflecting mirror 62 oscillates around the vertical axis, and the first reflecting mirror 62 and the second reflecting mirror. 72 and the third reflecting mirror 74 oscillate around the horizontal axis together with the first holding frame 64.

  In the case of vertical axis resonance and horizontal axis resonance, as shown in FIG. 10B, the measurement light (solid line) reflected by the portion 62A of the first reflecting mirror 62 is projected onto the region 96 of the projection surface 94. Lighted. As the first reflecting mirror 62 rotates and oscillates about the vertical axis and also rotates about the horizontal axis, the measurement light is scanned in the vertical direction and the horizontal direction as shown by arrows. The scanning locus meanders to draw a sine curve. On the other hand, the measurement light (dotted line) reflected by the second reflecting mirror 72 is projected onto the region 98 of the projection surface 94. As the second reflecting mirror 72 rotates and vibrates around the vertical axis, the measurement light is scanned in the vertical direction as shown by the arrows.

  Further, as shown in FIG. 6, measurement in two fields of view is possible even in the case of vertical axis non-resonance and horizontal axis non-resonance. The user may input an instruction via the display input unit 42 as to which state the measurement is to be performed.

  As described above, according to the present embodiment, the optical scanning device having a plurality of light projecting / receiving reflectors is used in the light projecting / receiving optical system, and each of the plurality of light projecting / receiving mirrors is simultaneously irradiated with the measurement light. By doing so, the measurement light emitted from one laser light source and projected in different directions can be received by separate reflecting mirrors, and measurement in two fields of view is possible. By measuring two fields of view at the same time, the amount of information obtained is increased as compared with the measurement using a single field of view, and a detailed measurement of an object becomes possible.

  Further, a combination in which each of the vertical axis and the horizontal axis is resonant or non-resonant is possible, and various measurements are possible as compared with the measurement in a single visual field.

<Other variations>
(Emitter / receiver optical system)
In the above embodiment, the example in which the measurement light and the reflected light are separated using the perforated reflecting mirror has been described. However, the separation optical system is not limited to the configuration shown in FIG. Other separation optical systems that separate measurement light and reflected light may be used. For example, a beam splitter such as a semi-transparent mirror may be used.

(MEMS mirror)
In the above-described embodiment, an example in which the optical scanning device is configured as an electromagnetically driven MEMS mirror has been described. However, it is only necessary to obtain a rotational operation similar to the above, and other driving type MEMS mirrors may be used. For example, it is good also as a MEMS mirror of an electrostatic drive system, a magnetic drive system, and a piezoelectric drive system.

DESCRIPTION OF SYMBOLS 10 Distance measuring device 20 Light projection part 24 Laser light source 26 Laser drive part 28 Scan drive part 30 Light receiving part 32 Photo detector 34 Light receiving element 40 Control part 42 Display input part 50 Light projecting / receiving optical system 52 Lens 54 Perforated reflector 54A Hole 54B Reflective surface 54C Region 54D Region 56 Lens 60 Optical scanning device 60A Reflective surface 62 First reflector 62A Part 62B Part 64 First holding frame 66 Second holding frame 68A First support beam 68B First Support beam 70A Second support beam 70B Second support beam 72 Second reflecting mirror 74 Third reflecting mirror 76 Driving coil 77 Wiring 78 Power supply 80 Driving coil 82 Power supply 83 Wiring 84A, 84B Permanent magnets 86A, 86B Permanent Magnet 90 Irradiation area 92 Light reception area 94 Projection plane 96 Area 98 Area F Focus L Optical axis

Claims (3)

A laser light source for emitting measurement light to be projected onto the measurement object;
A photodetector for detecting reflected light reflected by the measurement object;
A first reflecting mirror, a first holding frame disposed around the first reflecting mirror, and the first reflecting mirror are pivotally supported around a vertical axis with respect to the first holding frame. A first support beam, a second reflecting mirror disposed on one of the upper and lower surfaces of the first holding frame, and a third disposed on the other of the upper and lower surfaces of the first holding frame. And a second holding frame disposed around the first holding frame, and a first holding frame rotatably supported about the horizontal axis with respect to the second holding frame. An optical scanning device including two support beams and configured to be capable of two-dimensional scanning;
The measurement light emitted from the laser light source is guided to the optical scanning device so that the first reflection mirror and the second reflection mirror are irradiated, and the first reflection mirror and A light guide optical system for guiding the reflected light received by the third reflecting mirror to the photodetector;
A control unit that drives and controls each of the laser light source and the optical scanning device, and calculates a distance to the measurement object based on a detection signal of the photodetector.
Distance measuring device with   The light detector receives the first reflected light received by the first reflecting mirror and guided to the photodetector, and the light received by the third reflecting mirror and the light. The distance measuring device according to claim 1, further comprising: a second light receiving element that receives the second reflected light guided to the detector, and outputs a detection signal for each light receiving element.   The control section drives and controls the optical scanning device so that at least one of rotation of the first reflecting mirror around the vertical axis and rotation of the first support frame around the horizontal axis is performed. The distance measuring device according to claim 1 or 2.