Optical ranging device

Abstract

An optical ranging device 100 comprises: a light projection unit 12; a first deflection mechanism 16 provided with a deflection mirror 28a capable of oscillating about a first axis P1; light reception units 80A, 80B having a plurality of light reception elements 44a arranged along a direction around the first axis P1; a second deflection mechanism 20 for rotationally driving the first deflection mechanism 16 and the light reception units 80A, 80B about a second axis P2; a reference reflection member 22 irradiated with measurement light resulting from emission from the light projection unit 12 and deflection and reflection by the deflection mirror 28a; and a control unit that calculates the distance to an object on the basis of the measurement light and reflected light. The light reception unit 80A is provided corresponding to a first visual field V1, and the light reception unit 80B is provided corresponding to a second visual field V2. The light reception units 80A, 80B are disposed symmetrically relative to a second reference plane R2 which includes the second axis P2.

Description

optical distance measuring device

[0001] The present invention relates to an optical distance measuring device.

[0002] Distance measuring devices that measure the distance to an object using a time-of-flight (TOF) method are known. Distance measuring devices that use the TOF method can measure the distance to an object by detecting the time from when a measurement light is irradiated onto the object to when the reflected light of the measurement light is received.

[0003] For example, the laser distance measurement device disclosed in Patent Document 1 includes a MEMS mirror that deflects output light from a light source, a photodetector that detects reflected light from the output light reflected by an object, a photodetector circuit board that amplifies a signal based on the reflected light detected by the photodetector, a control circuit board that measures the distance to the object based on the signal output from the photodetector circuit board, and a rotation mechanism that rotates an optical system including the light source, the MEMS mirror, and the photodetector.

[0004] The photodetector has a plurality of detecting elements, the receiver circuit board has a plurality of transimpedance amplifiers, a switching circuit, and an amplifier circuit, and the control circuit board has a control circuit, a TDC circuit, and a signal processing circuit.

[0005] The multiple transimpedance amplifiers on the receiving circuit board are connected to the multiple detecting elements of the photodetector, respectively, and convert the currents generated by the detecting elements into voltages and output the resulting electrical signals to the switching circuit. The switching circuit outputs an electrical signal based on the current generated by a detecting element selected by a control circuit on the control circuit board to the amplifier circuit via the transimpedance amplifiers. The amplifier circuit amplifies the electrical signal output from the switching circuit and outputs it to the TDC circuit on the control circuit board. The TDC circuit on the control circuit board outputs a signal indicating the time difference between the pulse signal input from the control circuit and the electrical signal input from the amplifier circuit to the signal processing circuit. The signal processing circuit calculates the distance to the object from the time corresponding to the signal input from the TDC circuit and the speed of light.

[0006] In the laser distance measurement device of Patent Document 1, with the above-described configuration, three-dimensional distance measurement can be performed by rotating the optical system using a rotation mechanism and scanning the output light two-dimensionally using a MEMS mirror.

[0007] Japanese Patent Application Laid-Open No. 2018-128432

[0008] In the laser distance measuring device described above, in order to increase the measurement range (field of view angle) at a given focal length, it is necessary to increase the size of each detection element, which, however, significantly increases the manufacturing cost of the detection elements and therefore the manufacturing cost of the distance measuring device.

[0009] Therefore, one example of the object of the present invention is to provide a technology that can increase the measurement range while suppressing an increase in manufacturing costs in an optical distance measuring device that has multiple light receiving elements arranged in a predetermined direction.

[0010] (1) In order to achieve the above object, an optical distance measuring device according to one aspect of the present invention includes a light projecting unit that projects measurement light, a first deflection mechanism including an optical deflection unit that deflects and reflects the measurement light projected from the light projecting unit and that is equipped with a movable unit that can swing around a first axis and a drive unit that drives the movable unit to swing, a plurality of light receiving units each having a plurality of light receiving elements that are arranged in a predetermined direction along the direction around the first axis, and receiving light reflected from an object from the measurement light with any of the light receiving elements, a second deflection mechanism that drives to rotate at least the first deflection mechanism and the light receiving unit around a second axis that is different from the first axis, and a distance measuring device that controls the first deflection mechanism, the second deflection mechanism, the light projecting unit, and the light receiving unit to determine a distance based on the measurement light and the reflected light. and a control unit that calculates the distance to the object based on the deflection of the measurement light by the optical deflection unit, wherein the measurement light is deflected and reflected by the optical deflection unit, so that the measurement light is scanned along the direction around the first axis to one side and the other side of a first reference plane that intersects with the second axis, and the plurality of light receiving units include a first light receiving unit provided corresponding to a first field of view that includes an area on the one side of the first reference plane within the scanning range of the measurement light along the direction around the first axis, and a second light receiving unit provided corresponding to a second field of view that includes an area on the other side of the first reference plane within the scanning range, and is different from the first field of view, and the first light receiving unit and the second light receiving unit are arranged symmetrically with respect to a second reference plane that includes the direction around the first axis and includes the second axis.

[0011] In the optical distance measuring device described above, the plurality of light receiving elements provided in the first light receiving unit detects reflected light from the first field of view, and the plurality of light receiving elements provided in the second light receiving unit detects reflected light from the second field of view. In this case, it is not necessary to increase the dimensions of the light receiving elements compared to when the reflected light from the first field of view and the second field of view is detected by a single light receiving unit. In other words, it is possible to increase the measurement range while suppressing an increase in the manufacturing cost of the optical distance measuring device.

[0012] Furthermore, in the optical distance measuring device described above, the first light receiving unit and the second light receiving unit are arranged symmetrically with respect to the second reference plane. In other words, the first light receiving unit and the second light receiving unit are arranged symmetrically with respect to the first deflection mechanism and the second axis. In this case, it is possible to prevent the weight balance of the first deflection mechanism, the first light receiving unit, and the second light receiving unit from becoming poor in the direction around the second axis. This allows the second deflection mechanism to stably rotate the first deflection mechanism, the first light receiving unit, and the second light receiving unit around the second axis.

[0013] (2) In the optical distance measuring device, one of the two regions obtained by dividing the scanning range by the first reference plane may be the first field of view, and the other of the two regions obtained by dividing the scanning range by the first reference plane may be the second field of view. In this case, the first light receiving unit and the second light receiving unit can detect all reflected light from the scanning range of the measurement light.

[0014] (3) In the optical distance measuring device described above, the first light receiving unit and the second light receiving unit may each be optically designed to have a common optical configuration, include a light receiving lens that collects the reflected light, and the plurality of light receiving elements that are arranged in the predetermined direction and receive the reflected light collected by the light receiving lens at either one of the light receiving elements, and are attached to the second deflection mechanism at an angle relative to each other so as to face the corresponding first field of view or second field of view. In this case, since two light receiving units having a common configuration can be used, the design of the optical distance measuring device can be simplified and component costs can be reduced compared to when two light receiving units having different configurations are used.

[0015] (4) In the optical distance measuring device, the first light receiving unit and the second light receiving unit may each have a housing that mounts the light receiving lens and the plurality of light receiving elements to the second deflection mechanism, and the two housings may define a space between them as a guide through which the measurement light passes as scanned by the first deflection mechanism in the direction around the first axis. In this case, the measurement light can be projected accurately in a desired direction, improving measurement accuracy.

[0016] (5) In the optical distance measuring device described above, the first deflection mechanism may be configured to include a fixed portion supported by the second deflection mechanism so as to be rotatable around the second axis, and a beam portion that supports the movable portion on the fixed portion, and the beam portion may be driven torsionally in rotation or flexibly in oscillation by the drive unit and function as the first axis.

[0017] A first deflection mechanism in which a movable part is supported by a fixed part via a beam part that is torsionally rotated by a drive part can be constructed using, for example, MEMS (Micro Electro Mechanical Systems) technology to be extremely small and lightweight, and can be driven to oscillate at high speed. For example, the movable part supported by the beam part can be repeatedly oscillated by utilizing the force generated by applying a voltage to a piezoelectric element or a magnetostrictive element. Another technique can be used in which a planar coil is formed on the movable part, and the Lorentz force is applied to the coil by an alternating current flowing through the coil and a magnetic field generated by a permanent magnet provided on the fixed part, thereby oscillating the movable part. Another technique can be used in which a movable part supported by a cantilever beam is oscillated by bending back and forth. Using such techniques, a small, lightweight, and high-speed optical distance measuring device can be realized.

[0018] (6) The optical ranging device may further include a non-contact power supply unit having a power receiving unit arranged to rotate around the second axis in accordance with the rotation of the second deflection mechanism, and a power transmitting unit arranged opposite the power receiving unit on a common axis, and the non-contact power supply unit may supply power from the power transmitting unit to the power receiving unit.

[0019] For example, when current flows through a first coil serving as a power transmitter arranged opposite a second coil serving as a power receiver, an electromotive force is generated in the second coil by electromagnetic induction, and power can be supplied from the second coil to a drive unit of a first deflection mechanism that rotates around the second axis together with the second coil. In this case, power can be supplied from the first coil to the second coil contactlessly, eliminating the need for a slider structure with limited mechanical life. As a result, the life of the optical distance measuring device can be improved. The contactless power supply unit is not limited to the electromagnetic induction type described above, and may also be based on other methods, such as electric field coupling.

[0020] (7) The above-mentioned optical distance measuring device may further include a reference reflecting member onto which the measurement light emitted from the light-projecting unit and deflected and reflected by the optical deflection unit is irradiated, and a swing control unit that controls the drive unit of the first deflection mechanism, and a control signal from the swing control unit may be transmitted to the drive unit.

[0021] When the resonant frequency of the movable part and the member that supports it for oscillation fluctuates due to factors such as temperature fluctuations, the oscillation amplitude of the movable part fluctuates accordingly. Therefore, in order to maintain the predetermined oscillation amplitude, it is necessary to measure the fluctuations in the oscillation amplitude and control the drive unit that drives the movable part to oscillate. If a sensor that measures the oscillation amplitude of the movable part of the first deflection mechanism is provided for this purpose, a configuration for externally outputting the signal output of the sensor is required, which complicates the device configuration. In this regard, the optical distance measuring device described above can detect and control the oscillation amplitude of the movable part (optical deflection unit) based on the reflected light from the reference reflecting member out of the measurement light emitted from the light projector. In this case, there is no need to provide a sensor that measures the oscillation amplitude of the movable part, which simplifies the configuration of the deflection device.

[0022] (8) In the optical distance measuring device described above, the reference reflecting member may have an area with uniform reflectivity around the second axis, and the swing control unit may have an amplitude detection unit that detects the swing amplitude caused by the first deflection mechanism based on the light reflected by the light receiving unit from the area with uniform reflectivity of the reference reflecting member, and an amplitude control unit that controls the drive unit so that the swing amplitude detected by the amplitude detection unit becomes a predetermined swing amplitude. In this case, the swing amplitude of the movable part can be detected based on the light reflected from the area with uniform reflectivity, thereby preventing the occurrence of errors due to changes in the reflectivity of the reference reflecting member and enabling more accurate control of the movable part.

[0023] (9) In the optical distance measuring device, the drive unit may include a piezoelectric element for driving the movable unit, and the amplitude control unit may control the voltage applied to the piezoelectric element. In this case, as described above, a small, lightweight, and high-speed optical distance measuring device can be realized.

[0024] (10) In the optical distance measuring device, the driving unit may include a driving coil formed on the movable unit, and the amplitude control unit may control a current applied to the coil. In this case, as described above, a small, lightweight, and high-speed optical distance measuring device can be realized.

[0025] (11) The optical distance measuring device may further include a synchronization control unit that adjusts the rotation period of the second deflection mechanism and / or the measurement period of the measurement light emitted from the light projector in synchronization with the oscillation period of the movable unit. If the oscillation period of the movable unit changes to control the amplitude to a predetermined value, the measurement direction may change, making it impossible to obtain measurement values ​​corresponding to the required measurement direction. Furthermore, the number of required measurement values ​​within the oscillation period may increase or decrease. Even in such cases, if the synchronization control unit adjusts the measurement period of the measurement light and / or the rotation period of the second deflection mechanism based on a synchronization signal synchronized with the oscillation period of the movable unit, measurement values ​​corresponding to the required measurement direction may be obtained even if the oscillation period of the movable unit changes.

[0026] (12) The optical distance measuring device may further include a light adjusting unit that adjusts the intensity or light emission interval of the measurement light emitted from the light receiving unit based on the light reflected from the reference reflecting member received by the light receiving unit. Fluctuations in the intensity of the measurement light emitted from the light projecting unit may result in a decrease in measurement accuracy, and the intensity of the measurement light may deviate from the reference. Even in such cases, the light adjusting unit adjusts the intensity of the measurement light based on the light reflected from the reference reflecting member for amplitude adjustment, eliminating the need for a separate dedicated reference reflecting member.

[0027] According to the optical distance measuring device of the present invention, it is possible to increase the measurement range while suppressing an increase in manufacturing costs.

[0028] FIG. 1 is a schematic diagram showing an optical distance measuring device according to an embodiment of the present invention. FIG. 2 is a schematic diagram showing an optical distance measuring device according to an embodiment of the present invention. FIG. 3 is a schematic diagram showing the relationship between the measurement light and the deflection mirror. FIG. 4 is a schematic diagram showing the positional relationship between a first deflection mechanism, a light-receiving unit, and a second deflection mechanism. FIG. 5A is a schematic diagram showing the positional relationship between one light-receiving unit and the second deflection mechanism. FIG. 5B is a schematic diagram showing the positional relationship between the other light-receiving unit and the second deflection mechanism. FIG. 6 is a schematic diagram showing the relationship between a light-receiving lens and a detector. FIG. 7 is a schematic diagram showing the internal structure of the second deflection mechanism. FIG. 8 is a cross-sectional view of the casing and the reference reflecting member corresponding to the A-A portion of FIG. 2. FIG. 9 is an exploded view of the reference reflecting member. FIG. 10 is a diagram showing the configuration of a portion of the signal processing unit. FIG. 11 is a diagram for explaining a method for detecting the amplitude of the movable unit (deflection mirror) using an amplitude detection unit. FIG. 12 is a diagram for explaining a method for detecting the amplitude of the movable unit (deflection mirror) using an amplitude detection unit. Fig. 13 is a diagram for explaining another example of the signal processing unit, and Fig. 14 is a diagram for explaining another example of the first deflection mechanism.

[0029] An optical distance measuring device according to an embodiment of the present invention will now be described with reference to the drawings.

[0030] (Device Configuration) Figures 1 and 2 are schematic diagrams showing an optical distance measuring device according to one embodiment of the present invention. Note that Figure 2 shows the optical distance measuring device 100 in a state in which a first deflection mechanism 16, which will be described later, faces in the opposite direction to the optical distance measuring device 100 shown in Figure 1. The optical distance measuring device 100 according to this embodiment is a device that measures the distance to an object using a TOF method. Specifically, the optical distance measuring device 100 projects measurement light into a space to be measured, receives light reflected by an object (hereinafter referred to as the object) in the space to be measured, and calculates the distance to the object based on the timing at which the reflected light is received.

[0031] 1 and 2, the optical distance measuring device 100 according to this embodiment includes a casing 10, a light projecting unit 12, and a deflection device 14. The light projecting unit 12 and the deflection device 14 are housed within the casing 10. In this embodiment, the casing 10 includes a cylindrical side wall 10a, a bottom plate 10b provided at one end of the side wall 10a, and a top plate 10c provided at the other end of the side wall 10a. An optical window 10d is formed in the side wall 10a to allow measurement light and reflected light to pass through.

[0032] Although not shown, the light projecting unit 12 includes a light emitting element such as a laser diode, a light source driving unit that pulse-drives the light emitting element, and a light projecting lens that shapes the measurement light (laser light) emitted from the light emitting element into a parallel beam. In this embodiment, the light emitting element of the light projecting unit 12 emits the measurement light in synchronization with a control signal output from a signal processing unit 24 (described later). The measurement light is pulsed light having a pulse width of, for example, several hundred picoseconds to several tens of nanoseconds.

[0033] The deflection device 14 includes a first deflection mechanism 16, a light-receiving unit 18, a second deflection mechanism 20, a reference reflecting member 22, and a signal processing unit 24. The light-projecting unit 12, the first deflection mechanism 16, and the light-receiving unit 18 are rotated around a second axis P2 by the second deflection mechanism 20. In this embodiment, the light-projecting unit 12 projects measurement light along the second axis P2. In this embodiment, the first deflection mechanism 16 is supported by the second deflection mechanism 20 so that a deflection mirror 28a (described later) is positioned on the second axis P2. Note that the first deflection mechanism 16 only needs to be supported by the second deflection mechanism 20; the deflection mirror 28a does not necessarily have to be positioned on the second axis P2. As will be described in detail later, the light-receiving unit 18 is supported by the second deflection mechanism 20 at a position offset from the second axis P2. In this embodiment, the signal processing unit 24 is mainly housed in the rotating second deflection mechanism 20. The support base 47 is hollow and houses a part of the signal processing unit 24 therein.

[0034] The first deflection mechanism can be configured using a known MEMS mirror, so the following will simply describe the configuration of the first deflection mechanism 16.

[0035] The first deflection mechanism 16 includes a movable part 28 having a deflection mirror 28a, and a pair of beams 31 (see FIG. 8) made of a metal material that supports the movable part 28 so that the movable part 28 can swing about a first axis P1 (see FIGS. 3 and 8) relative to a fixed part 29 (see FIG. 8, which will be described later). The fixed part 29 is supported by the second deflection mechanism 20. In this embodiment, the first deflection mechanism 16 repeatedly swings the movable part 28 about the first axis P1 using a piezoelectric element (or a magnetostrictive element) that serves as a drive unit 33 (see FIG. 8) provided on the fixed part 29.

[0036] In this embodiment, the deflection mirror 28a included in the movable portion 28 has a configuration in which, for example, gold, aluminum, or the like is vapor-deposited on a glass substrate or a silicon substrate. In this embodiment, the deflection mirror 28a corresponds to the light deflection portion.

[0037] 3 is a schematic diagram showing the relationship between the measurement light and the deflection mirror 28a. In FIG. 3, the original position of the deflection mirror 28a is indicated by a solid line, and the position of the deflection mirror 28a after it has rotated from the original position around the first axis P1 is indicated by a dashed line. Furthermore, the measurement light projected from the light projector 12 onto the deflection mirror 28a and the measurement light reflected by the deflection mirror 28a in the original position are indicated by solid arrows, and the measurement light reflected by the deflection mirror 28a after it has rotated from the original position around the first axis P1 is indicated by a dashed arrow.

[0038] As shown in FIG. 3 , in this embodiment, the deflection mirror 28a (movable unit 28) is driven to swing around the first axis P1 while the light projector 12 irradiates the deflection mirror 28a with measurement light. This deflects the measurement light to scan a predetermined range around the first axis P1. Hereinafter, the range scanned by the measurement light deflected and reflected by the deflection mirror 28a is referred to as the scanning range S. In this embodiment, the measurement light scans one side and the other side of a first reference plane R1 that intersects with the second axis P2 around the first axis P1. In this embodiment, the first reference plane R1 is a plane perpendicular to the second axis P2. Hereinafter, within the scanning range S, the region on one side of the first reference plane R1 is referred to as the first field of view V1, and the region on the other side of the first reference plane R1 is referred to as the second field of view V2. In this embodiment, for example, by oscillating the deflection mirror 28a at a mechanical angle of ±7.5° around the first axis P1, the measurement light deflected by the deflection mirror 28a can be scanned within a range of ±15° around the first axis P1.

[0039] 4 is a schematic diagram showing the positional relationship between the first deflection mechanism 16, the light-receiving unit 18, and the second deflection mechanism 20. Note that in FIG. 4, the deflection mirror 28a of the first deflection mechanism 16 and a rotor 50 (described later) of the second deflection mechanism 20 are shown in simplified form.

[0040] 1, 2, and 4, the light-receiving unit 18 has multiple (two in this embodiment) light-receiving sections 80A and 80B. Figures 5A and 5B are schematic diagrams showing the positional relationship between the light-receiving sections 80A and 80B and the second deflection mechanism 20. Specifically, Figure 5A shows the positional relationship between the light-receiving section 80A and the second deflection mechanism 20, and Figure 5B shows the positional relationship between the light-receiving section 80B and the second deflection mechanism 20.

[0041] As shown in Figures 5A and 5B, in this embodiment, the light receiving units 80A and 80B have a common optical design. In this embodiment, the light receiving units 80A and 80B have the same configuration, each including a housing 40 with an optical window 40a formed therein, a light receiving lens 42, and a detector 44. The light receiving lens 42 and the detector 44 are housed within the housing 40. Light reflected by the object passes through the optical window 40a and enters the light receiving lens 42, where it is focused toward the detector 44 by the light receiving lens 42. Note that in Figures 5A and 5B, an optical axis OA that passes through the center of the light receiving lens 42 and is perpendicular to the lens surface of the light receiving lens 42 is shown by a dashed line.

[0042] In this embodiment, the light receiving unit 80A is provided corresponding to the first field of view V1 (see FIG. 3 ), and the light receiving unit 80B is provided corresponding to the second field of view V2 (see FIG. 3 ). Specifically, the light receiving units 80A and 80B are attached to the rotor 50 of the second deflection mechanism 20 at an angle relative to each other so as to face the first field of view V1 or the second field of view V2. In this embodiment, the light receiving units 80A and 80B are fixed to the rotor 50 via support bases 45a and 45b so that the optical axes OA of the light receiving units 80A and 80B are inclined in opposite directions relative to the top surface of the rotor 50 when viewed from the direction along the first axis P1 (see FIG. 4 ). In this embodiment, the top surface of the rotor 50 is provided parallel to the first reference plane R1 (see FIG. 3 ). Therefore, when viewed from the direction along the first axis P1 (see FIG. 4), the optical axis OA of the light receiving unit 80A and the optical axis OA of the light receiving unit 80B are inclined in opposite directions with respect to the first reference plane R1. In this embodiment, the light receiving unit 80A corresponds to the first light receiving unit, and the light receiving unit 80B corresponds to the second light receiving unit.

[0043] FIG. 6 is a diagram showing the relationship between the light-receiving lens 42 and the detector 44. As shown in FIG. 6, in this embodiment, the detector 44 has multiple light-receiving elements 44a and a circuit board 44b. In the example shown in FIG. 6, the detector 44 has 16 light-receiving elements 44a. The multiple light-receiving elements 44a are arranged in a direction along the direction around the first axis P1 (see FIG. 4). In this embodiment, the multiple light-receiving elements 44a are arranged in a one-dimensional direction along the direction around the first axis P1. For example, if the first axis P1 is parallel to the horizontal direction and the deflection mirror 28a scans the measurement light emitted from the light-projecting unit 12 in the vertical direction, the multiple light-receiving elements 44a are arranged in a vertical line and in a linear or arc shape when viewed from the direction along the first axis P1.

[0044] As described above, the measurement light (parallel light) emitted from the light-emitting unit 12 is projected onto the measurement target space at an angle (scanning angle) corresponding to the swing angle of the deflection mirror 28a. In this case, the reflected light reflected by the target object is incident on the light-receiving lens 42 at an angle corresponding to the scanning angle of the measurement light. In this embodiment, the light-receiving lens 42 and the detector 44 are arranged so that one of the multiple light-receiving elements 44a receives the reflected light depending on the incident angle of the reflected light entering the light-receiving lens 42 from the first field of view V1 (see FIG. 3) or the second field of view V2 (see FIG. 3). In this embodiment, the reflected light (pulsed light) of the measurement light scanned in a predetermined direction by the deflection mirror 28a is incident on the multiple light-receiving elements 44a in sequence. As a result, the reflected light (pulsed light) is detected in sequence by the multiple light-receiving elements 44a. The reflected light being incident on the plurality of light receiving elements 44 a in sequence includes not only the case where the reflected light is incident on each light receiving element 44 a in sequence once, but also the case where the reflected light is incident on each light receiving element 44 a in sequence multiple times. For example, the reflected light may be incident on each light receiving element 44 a in sequence twice.

[0045] The multiple light-receiving elements 44a may be, for example, an APD array composed of multiple photodiodes. Although not shown, the circuit board 44b includes an amplifier circuit, a switching circuit, and the like. In this embodiment, a distance measurement calculation unit constructed in the signal processing unit 24 determines the time difference between the emission of the measurement light and the reception of the reflected light, and calculates the distance from the optical distance measuring device 100 to the object based on this time difference. Specifically, in this embodiment, based on a control signal from a selection unit 72 (described later), one of the multiple light-receiving elements 44a on the circuit board 44b of the detector 44 is selected according to the swing angle of the movable unit 28 (deflection mirror 28a). The distance measurement calculation unit of the signal processing unit 24 calculates the distance to the object based on the measurement light received by the selected light-receiving element 44a. Since a known method can be used to calculate the distance from the optical distance measuring device 100 to the object, detailed description thereof will be omitted.

[0046] Fig. 7 is a schematic diagram showing the internal structure of the second deflection mechanism 20. As shown in Fig. 7, the second deflection mechanism 20 includes a stator 46 and a rotor 50 rotatably supported by the stator 46 via a hollow shaft 48. In this embodiment, a coil (not shown) is provided in the stator 46, and a magnet (not shown) is provided in the rotor 50, and the stator 46, shaft 48, and rotor 50 are configured as an outer rotor type motor 51.

[0047] 1 , the stator 46 of the motor 51 is fixed to the casing 10 via a support base 47. Furthermore, the light-projecting unit 12, the first deflection mechanism 16, and the light-receiving units 80A and 80B (housing 40) are fixed to the rotor 50 of the motor 51. In this embodiment, the light-projecting unit 12 is fixed to the rotor 50 via a support member 13, and the first deflection mechanism 16 is fixed to the rotor 50 via a plurality of support members 17.

[0048] In this embodiment, the motor 51 is controlled by the signal processing unit 24. The motor 51 is provided with an encoder (not shown) for detecting the rotation angle of the rotor 50. A detection signal from the encoder is sent to the signal processing unit 24. The signal processing unit 24 is composed of an electronic circuit including a microcomputer and the like, and includes at least a control block for the light-projecting unit 12, a control block for the first deflection mechanism 16, a control block for the light-receiving unit 18, a control block for the second deflection mechanism 20, and a calculation block for performing distance measurement calculations. In this embodiment, the signal processing unit 24 corresponds to a control unit that controls the first deflection mechanism, the second deflection mechanism, the light-projecting unit, and the light-receiving unit, and calculates the distance to an object based on the measurement light and reflected light.

[0049] In this embodiment, by driving the motor 51, the light-projecting unit 12, the first deflection mechanism 16, and the light-receiving units 80A and 80B can be rotated about the second axis P2 relative to the casing 10. In this embodiment, the deflection mirror 28a, which is driven to swing about the first axis P1, is driven to rotate about the second axis P2 by the second deflection mechanism 20, so that the measurement light deflected and reflected by the deflection mirror 28a is scanned two-dimensionally.

[0050] 7, hollow disk-shaped support members 52, 54 that support coils 56, 58 are provided between the stator 46 and the rotor 50 in the motor 51. The support member 52 is fixed to the stator 46, and the support member 54 is fixed to the rotor 50. The coils 56, 58 are provided on the support members 52, 54 so as to face each other on a common axis. In this embodiment, the coils 56, 58 are provided so as to face each other on the second axis P2.

[0051] When the motor 51 is driven, the coil 58 rotates around the second axis P2 together with the support member 54 in conjunction with the rotation of the rotor 50. On the other hand, the coil 56 does not rotate because it is fixed to the stator 46 via the support member 52. In this embodiment, the coils 56 and 58 form an electromagnetic induction type contactless power supply unit 60. In this embodiment, the coil 56 corresponds to the power transmitting unit, and the coil 58 corresponds to the power receiving unit.

[0052] The coil 56 is electrically connected to the signal processing unit 24 (see FIG. 1 ) by wiring (not shown). The coil 58 is electrically connected to the signal processing unit 24 inside the second deflection mechanism 20 and to a drive unit 33 (see FIG. 8 ) that drives the movable unit 28 of the first deflection mechanism 16 to swing. In the non-contact power supply unit 60 of this embodiment, an AC current of a predetermined frequency is applied to the coil 56. When an AC current is applied to the coil 56, an AC current of the predetermined frequency also flows through the coil 58, which rotates relative to the coil 56, due to electromagnetic induction. This supplies power to the second deflection mechanism 20, which rotates around the second axis P2.

[0053] Although not shown, power may be supplied from the coil 58 of the non-contact power supply unit 60 to the light projector 12 and the light receiving unit 18 by, for example, wiring (a contact-type transmission path). Signals may be transmitted and received between the non-contact power supply units 60 by, for example, a transmission path that combines optical fiber or an optical link with wiring using a slider or the like. In this embodiment, for example, the space inside the stator 46 and the shaft 48 can be used to provide the transmission path.

[0054] FIG. 8 is a cross-sectional view of the casing 10 and the reference reflecting member 22 corresponding to the A-A portion of FIG. 2 . Note that FIG. 8 also shows a simplified version of the first deflection mechanism 16. As shown in FIG. 8 , the reference reflecting member 22 is fixed to the inside of the casing 10. In this embodiment, the reference reflecting member 22 is disposed along the inner circumferential surface of the casing 10 when viewed in the direction along the second axis P2. The reference reflecting member 22 is disposed in an area of ​​the casing 10 where the optical window 10d is not formed. In this embodiment, a 270° range around the second axis P2 is set as the measurement area, and the optical window 10d is formed in this range. The remaining 90° range is set as the non-measurement area, and the reference reflecting member 22 is disposed in a portion of this area. The reference reflecting member 22 is disposed so as to reflect the measurement light deflected and reflected by the deflection mirror 28a. In this embodiment, the measurement light is reflected with equal reflectivity from the entire surface of the reference reflecting member 22.

[0055] In this embodiment, the first deflection mechanism 16 is disposed between the light receiving units 80A and 80B ( FIG. 4 ) in the direction along the first axis P1. In this embodiment, the light receiving units 80A and 80B are disposed symmetrically with respect to a second reference plane R2 (see FIG. 8 ), which includes the direction around the first axis P1 and the second axis P2. In this embodiment, the second reference plane R2 is a plane perpendicular to the first axis P1. With this configuration, as shown in FIG. 4 , the deflection mirror 28a deflects and reflects the measurement light between the light receiving units 80A and 80B, scanning the measurement light along the direction around the first axis P1. In this embodiment, the two housings 40 of the light receiving units 80A and 80B define a space 82 between them as a guide through which the measurement light passes as it scans along the direction around the first axis P1.

[0056] FIG. 9 is a diagram showing the reference reflecting member 22 in an expanded state. Note that in FIG. 9 , the trajectory of the measurement light irradiated onto the reference reflecting member 22 when the movable portion 28 (deflection mirror 28 a) is oscillating at the target oscillation amplitude is indicated by a dashed line. Also, in FIG. 9 , multiple light-receiving elements 44 a of the light-receiving units 80A and 80B are shown to illustrate the relationship between the irradiation position of the measurement light on the reference reflecting member 22 and the light-receiving elements 44 a that detect the reflected light reflected at that irradiation position. In this embodiment, each detector 44 of the light-receiving units 80A and 80B has 16 light-receiving elements 44 a. In this embodiment, the 16 light-receiving elements 44 a of the light-receiving unit 80A are set as light-receiving elements 44 a for channels 1 to 16, and the 16 light-receiving elements 44 a of the light-receiving unit 80B are set as light-receiving elements 44 a for channels 17 to 32.

[0057] 9, the length of the reference reflecting member 22 in the direction along the second axis P2 is slightly longer than twice the target amplitude A of the trajectory of the measurement light corresponding to the target oscillation amplitude of the deflection mirror 28a. The reference reflecting member 22 is positioned in the casing 10 so that the measurement light deflected and reflected by the deflection mirror 28a when the deflection mirror 28a is stopped is irradiated onto the center position of the reference reflecting member 22 in the direction along the second axis P2.

[0058] Fig. 10 is a diagram showing the configuration of a portion of the signal processing unit 24. As shown in Fig. 10, the signal processing unit 24 includes a swing control unit 70, a selection unit 72, and a synchronization control unit 74, which are configured by electronic circuits including a microcomputer, etc. The swing control unit 70 includes an amplitude detection unit 70a and an amplitude control unit 70b.

[0059] In this embodiment, when the detectors 44 of the light-receiving units 80A and 80B detect reflected light from the reference reflecting member 22, a detection signal is input from the detectors 44 to the swing control unit 70. As described below, the amplitude detection unit 70a of the swing control unit 70 detects the amplitude of the movable unit 28 (deflection mirror 28a) based on the detection signal input from the detector 44. The amplitude detected by the amplitude detection unit 70a is input to the amplitude control unit 70b. The amplitude control unit 70b adjusts the frequency of the AC signal (voltage or current; in this embodiment, voltage) applied to the drive unit 33 that drives the movable unit 28 of the first deflection mechanism 16 to swing, while maintaining the AC signal at a predetermined value, so that the amplitude detected by the amplitude detection unit 70a becomes the target swing amplitude of the movable unit 28. The control signal (AC signal) output from the amplitude control unit 70b is applied to the drive unit that drives the movable unit 28 of the first deflection mechanism 16 to swing.

[0060] A method for detecting the amplitude of the movable part 28 (deflection mirror 28a) by the amplitude detection unit 70a will be described below. In this embodiment, during the period in which the measurement light deflected and reflected by the deflection mirror 28a is irradiated onto the reference reflecting member 22, the selection unit 72 fixes the light receiving element 44a that receives the reflected light from the reference reflecting member 22 to one of the multiple light receiving elements 44a. The amplitude detection unit 70a includes a comparator that binarizes the reflected light from the reference reflecting member 22 received by the light receiving element 44a selected by the selection unit 72 using a predetermined threshold value. The time at which the detection signal of the comparator changes is calculated based on the step of the discrete measurement number.

[0061] FIG. 11 is a diagram illustrating an example of a method for detecting the amplitude of the movable part 28 (deflection mirror 28a) using the amplitude detector 70a. The upper part of FIG. 11 illustrates an expanded view of the reference reflecting member 22. The upper part of FIG. 11 illustrates, with a dashed line, the trajectory (amplitude A) of the measurement light irradiated onto the reference reflecting member 22 when the movable part 28 (deflection mirror 28a) is oscillating at a target oscillation amplitude, and the upper part of FIG. 11 illustrates, with a dashed line, the trajectory (amplitude B) of the measurement light irradiated onto the reference reflecting member 22 when the movable part 28 (deflection mirror 28a) is oscillating at an amplitude smaller than the target oscillation amplitude. The lower part of FIG. 11 illustrates the intensity of the received light signal detected by the comparator of the amplitude detector 70a based on the reflected light received by the 24-channel light-receiving element 44a.

[0062] Ideally, it is preferable that the movable part 28 be continuously oscillated so that the amplitude of the trajectory of the measurement light irradiated onto the reference reflecting member 22 becomes the target amplitude A. However, if the resonant frequency of the movable part 28 and the pair of beam parts 31 supporting the movable part 28 changes due to fluctuations in the environmental temperature or the like, the amplitude of the measurement light deviates from the target amplitude A. When the resonant frequency approaches the frequency of the control signal, the amplitude of the movable part 28 becomes larger, and when the resonant frequency deviates from the frequency of the control signal, the amplitude of the movable part 28 becomes smaller.

[0063] 11 , when the movable part 28 is vibrating at the target oscillation amplitude (when the amplitude of the measurement light trajectory is the target amplitude A), the received light intensity in a fixed channel (24ch in FIG. 11 ) is detected as two peak values ​​while the movable part 28 oscillates for one cycle. Here, if the center positions of the respective peak values ​​are defined as, for example, the center positions obtained from the respective peaks and are designated as times T11 and T12, then the difference value T13 (T12−T11) can be set as a control target value correlated with the amplitude of the movable part 28. Furthermore, the center position (T14) between times T11 and T12 can be detected as a control target value for the phase position of the movable part 28 (the point in time when the amplitude is maximum).

[0064] Similarly, when the movable part 28 vibrates at an amplitude smaller than the target oscillation amplitude (when the amplitude of the measurement light trajectory is amplitude B), the times showing two peak values ​​in one oscillation cycle are detected as T21 and T22, respectively, and the difference value T23 (T22 - T21) is detected as a control value correlated with the amplitude of the movable part 28. In addition, the center position (T24) between times T21 and T22 can be detected as a control value for the phase position (the point in time when the amplitude is maximum) of the movable part 28. In this way, the amplitude detection unit 70a can detect the oscillation amplitude and phase of the movable part 28 (deflection mirror 28a) using a signal based on the measurement light detected by the light-receiving element 44a selected by the selection unit 72.

[0065] When the difference value (e.g., T23 in FIG. 11 ) and the center position (e.g., T24 in FIG. 11 ) of the section detected by the amplitude detection unit 70 a deviate from the target values ​​(T13 or T14), the amplitude control unit 70 b variably controls the frequency while maintaining the signal (control signal) applied to the drive unit 33 of the first deflection mechanism 16 at a predetermined value so that the difference value and the center position become the target values. As a result, the amplitude of the movable unit 28 (deflection mirror 28 a) is maintained at the predetermined target amplitude.

[0066] The amplitude control unit 70b includes a calculation circuit that calculates the deviation between the difference value detected by the amplitude detection unit 70a and a target value for the difference value, and the deviation between the center position and the target value for the center position, a feedback calculation unit such as a PID calculation that calculates a control value for the frequency of the applied signal based on the deviation, and a circuit that generates a control signal that adjusts the frequency of the applied signal in accordance with the control value calculated by the feedback calculation unit.

[0067] In this embodiment, for example, the amplitude detection unit 70a detects the above-mentioned difference value and center position based on the rotation speed and rotation position of the motor 51, which are based on the output of an encoder provided on the motor 51, and the amplitude control unit 70b determines the oscillation frequency and amplitude of the movable part 28 from the above-mentioned difference value and center position.

[0068] The light-receiving element 44a selected by the selector 72 during the period when the measurement light deflected and reflected by the deflection mirror 28a is irradiated onto the reference reflecting member 22 may be changed for each rotation or a predetermined number of rotations of the motor 51. Furthermore, when the difference between the oscillation amplitude of the deflection mirror 28a and the target oscillation amplitude is equal to or less than a threshold, the light-receiving element 44a that receives the measurement light when the oscillation amplitude of the deflection mirror 28a is maximized may be fixed as the light-receiving element 44a selected during the period when the measurement light deflected and reflected by the deflection mirror 28a is irradiated onto the reference reflecting member 22. In this embodiment, for example, a 1-channel or 32-channel light-receiving element 44a may be selected during the period when the measurement light deflected and reflected by the deflection mirror 28a is irradiated onto the reference reflecting member 22, as shown in FIG. 12 , for example, one peak is detected during one oscillation cycle, and the time T3 of the peak interval (the time corresponding to T13 in FIG. 11 ) is a control value correlated with the oscillation amplitude of the movable part 28. Furthermore, the time T4 (=T14) at the center position of the peak is detected as the phase position of the movable part 28 (the time point at which the amplitude becomes maximum).

[0069] In this embodiment, the selector 72 selects one of the light-receiving elements 44a as a light-receiving element that receives the light reflected by the object, based on a control signal from the swing controller 70 (amplitude controller 70b), during a period when the measurement light deflected and reflected by the deflection mirror 28a is not irradiated onto the reference reflecting member 22 (a period when the measurement light is projected into the measurement target space). More specifically, the selector 72 selects one of the light-receiving elements 44a in response to the movement of the movable part 28 of the first deflection mechanism 16 around the first axis P1.

[0070] In addition, in this embodiment, the synchronization control unit 74 adjusts the rotation speed and rotation phase (rotation period) of the second deflection mechanism 20 (motor 51), as well as the timing of turning on the measurement light (measurement period), so that the measurement light is emitted in a predetermined measurement direction in synchronization with the oscillation phase (oscillation period) of the movable part 28 detected by the oscillation control unit 70.

[0071] 13, the signal processing unit 24 may include a light adjusting unit 76 that adjusts the intensity or light emission interval of the measurement light emitted from the light projecting unit 12 based on the reflected light from the reference reflecting member 22 received by the light receiving units 80A and 80B. Fluctuations in the intensity of the measurement light emitted from the light projecting unit 12 may result in a decrease in measurement accuracy and may cause the intensity of the laser light used as the light source to deviate from the standard. Even in such cases, the light adjusting unit 76 can adjust the intensity or light emission interval of the measurement light based on the reflected light from the reference reflecting member 22 used for amplitude adjustment, eliminating the need for a separate reference reflecting member dedicated to adjusting the light intensity.

[0072] For example, the oscillation angle of the movable part 28 can be determined from the amplitude and phase of the movable part 28 calculated based on the signal of an encoder that detects the reflected light from the reference reflecting member 22 and the rotation phase of the motor 51, and the timing of emitting the laser light can be controlled based on the oscillation angle. If the rotation speed and emission time interval of the motor 51 are kept constant, the density of the laser light increases near the maximum amplitude of the movable part 28. This can make it difficult to meet the criteria required near the maximum amplitude of the movable part 28. Even in such cases, the required criteria can be met by controlling the emission time interval of the laser diode to be longer near the maximum amplitude.

[0073] (Operation and Effect) In the optical distance measuring device 100 according to this embodiment, the plurality of light receiving elements 44a provided in the light receiving unit 80A detects reflected light from the first field of view V1, and the plurality of light receiving elements 44a provided in the light receiving unit 80B detects reflected light from the second field of view V2. In this case, it is not necessary to increase the dimensions of the light receiving elements 44a compared to when the light reflected from the first field of view V1 and the second field of view V2 is detected by a single light receiving unit. In other words, the measurement range can be increased while suppressing an increase in the manufacturing cost of the optical distance measuring device 100.

[0074] Furthermore, in the optical distance measuring device 100 according to this embodiment, the light receiving units 80A and 80B are disposed symmetrically with respect to the second reference plane R2. In other words, the light receiving units 80A and 80B are disposed symmetrically with respect to the first deflection mechanism 16 and the second axis P2. In this case, it is possible to prevent the weight balance of the first deflection mechanism 16 and the light receiving units 80A and 80B from becoming poor in the direction around the second axis P2. This allows the second deflection mechanism 20 to stably rotate the first deflection mechanism 16 and the light receiving units 80A and 80B around the second axis P2.

[0075] In this embodiment, the light receiving units 80A and 80B are optically designed to be the same, and are attached to the second deflection mechanism at an angle relative to each other so as to face the corresponding first field of view V1 or second field of view V2. In this case, two light receiving units having a common configuration can be used, which simplifies the design of the optical distance measuring device 100 and reduces component costs compared to when two light receiving units having different configurations are used.

[0076] In this embodiment, the two housings 40 of the light-receiving units 80A and 80B define a space 82 as a guide through which the measurement light deflected and reflected by the deflection mirror 28a passes. This allows the measurement light to be projected in a desired direction with high accuracy, improving measurement accuracy.

[0077] Furthermore, in this embodiment, the swing control unit 70 can control the drive unit 33 that drives the movable unit 28 of the first deflection mechanism 16, based on the reflected light from the reference reflecting member 22 that is received by some of the multiple light-receiving elements 44a of the light-receiving units 80A and 80B. In this case, there is no need to provide a separate sensor for measuring the swing amplitude of the movable unit 28 (deflection mirror 28a), so the manufacturing costs of the optical distance measuring device 100 can be reduced.

[0078] In particular, in this embodiment, the drive unit 33 that drives the movable part 28 of the first deflection mechanism 16 can be controlled based on the reflected light from the reference reflecting member 22 that is received by the light-receiving element 44a selected by the selector 72. In this case, by appropriately selecting the light-receiving element 44a by the selector 72, the drive unit 33 that drives the movable part 28 can be controlled with high precision.

[0079] In this embodiment, the light-receiving elements 44a of the light-receiving units 80A and 80B that receive the reflected light from the reference reflecting member 22 are fixed to one of the plurality of light-receiving elements 44a during the period when the measurement light is irradiated onto the reference reflecting member 22. In this case, since there is no need to perform switching control of the light-receiving elements 44a during the period when the measurement light is irradiated onto the reference reflecting member 22, the load on the selection unit 72 is reduced.

[0080] In this embodiment, during a period when the measurement light is not irradiated onto the reference reflecting member 22, the selector 72 selects one of the plurality of light-receiving elements 44a that receive the light reflected by the object, based on a control signal from the swing controller 70, in accordance with the movement of the movable part 28 around the first axis P1. In this case, the distance to the object can be accurately measured based on the signal from the appropriate light-receiving element 44a that corresponds to the movement of the movable part 28.

[0081] (Modification) In the above-described embodiment, the entire reference reflecting member 22 is configured to reflect the measurement light with the same reflectance. However, the reflectance of a portion of the reference reflecting member 22 may be lower than the reflectance of other portions. However, it is preferable that the reference reflecting member 22 has an area with the same reflectance along the second axis P2. The light-receiving element 44a that receives the reflected light reflected by the reference reflecting member 22 during the period when the measurement light is irradiated onto the reference reflecting member 22 is preferably selected to receive the reflected light reflected by the area with the same reflectance. For example, referring to FIG. 9 , when the selector 72 selects one of the light-receiving elements 44a for channels 1 to 5 or channels 28 to 32 during the period when the measurement light is irradiated onto the reference reflecting member 22, the reflectance of the area of ​​the reference reflecting member 22 corresponding to the light-receiving elements 44a for channels 6 to 27 may be lower than the reflectance of the area corresponding to the light-receiving elements 44a for channels 1 to 5 and channels 28 to 32. The term "equal reflectance" does not only mean that the reflectance is completely equal, but also that the reflectance is equal to an extent that does not affect the detection accuracy of the measurement light by the light receiving element 44a.

[0082] In the above-described embodiment, the selector 72 selects one light-receiving element 44a of the light-receiving unit 80B during the period when the measurement light is irradiated onto the reference reflecting member 22. However, the selector 72 may also select one light-receiving element 44a of the light-receiving unit 80A. In this case, during the period when the measurement light is irradiated onto the reference reflecting member 22, the one light-receiving element 44a selected by the selector 72 may be the light-receiving element 44a that receives reflected light based on the measurement light deflected and reflected by the deflection mirror 28a when the movable part 28 swings a predetermined angle from the original position to one side around the first axis P1, and the other light-receiving element 44a selected by the selector 72 may be the light-receiving element 44a that receives reflected light based on the measurement light deflected and reflected by the deflection mirror 28a when the movable part 28 swings a predetermined angle from the original position to the other side around the first axis P1. 9, for example, the 5-channel light-receiving element 44a of the light-receiving unit 80A and the 28-channel light-receiving element 44a of the light-receiving unit 80B may be selected. In this case, the movable unit 28 can be driven to swing with higher precision than when the movable unit 28 is controlled based on the detection result of one light-receiving element 44a.

[0083] In the above-described embodiment, the light receiving units 80A and 80B, which are optically designed in common, are arranged at an angle relative to each other so as to correspond to the first field of view V1 and the second field of view V2. However, the configuration of the light receiving units is not limited to the above example. For example, the positions of the detectors 44 relative to the light receiving lens 42 (optical axis OA) may be different between the light receiving units 80A and 80B. In this case, even if the optical axes OA of the light receiving units 80A and 80B are not inclined relative to each other when viewed from the direction along the first axis P1, it is possible to detect reflected light from the first field of view V1 with the detector 44 of the light receiving unit 80A and detect reflected light from the second field of view V2 with the detector 44 of the light receiving unit 80B.

[0084] In the above embodiment, the multiple light-receiving elements 44a of the light-receiving unit 80A detect reflected light from the first field of view V1, and the multiple light-receiving elements 44a of the light-receiving unit 80B detect reflected light from the second field of view V2. However, the reflected light detected by the light-receiving units 80A and 80B is not limited to the above example. For example, the multiple light-receiving elements 44a of the light-receiving unit 80A may detect reflected light from a portion of the second field of view V2 in addition to reflected light from the first field of view V1. Furthermore, the multiple light-receiving elements 44a of the light-receiving unit 80B may detect reflected light from a portion of the first field of view V1 in addition to reflected light from the second field of view V2. In other words, a portion of the field of view corresponding to the light-receiving unit 80A may overlap a portion of the field of view corresponding to the light-receiving unit 80B.

[0085] In the above embodiment, the case where the reflected light from the scanning range S of the measurement light by the deflection mirror 28a is detected by two light receiving units 80A and 80B has been described, but the reflected light from the scanning range S may be detected by three or more light receiving units. In this case, it is sufficient that each light receiving unit is provided to correspond to a different part of the scanning range S, and that the multiple light receiving units are arranged so that all of the reflected light from the scanning range S can be detected by the multiple light receiving units.

[0086] In the above embodiment, the movable part 28 is supported by a pair of beams that are driven to rotate in a torsional manner by the drive unit. However, the movable part 28 may also be supported by a beam that is driven to oscillate in a flexural manner by the drive unit. Alternatively, an elastic beam may be formed on only one of the movable parts, and the movable part may be driven to oscillate around the beam. As shown in FIG. 14 , the first deflection mechanism 16 may be configured such that a Lorentz force generated by a magnetic circuit 35 provided in the fixed part 29 as the drive unit 39 and a coil 37 provided in the movable part 28 repeatedly oscillates the movable part 28 around the first axis P1. In this case, the amplitude control unit 70b controls the current applied to the coil 37. The magnetic circuit 35 may be, for example, a pair of permanent magnets 35a and a yoke (not shown).

[0087] In the above embodiment, the reference reflecting member 22 is fixed inside the casing 10 , but the casing 10 itself may be used as the reference reflecting member 22 .

[0088] In the above-described embodiment, the light-projecting unit 12 is supported by the second deflection mechanism 20 so as to rotate integrally with the first deflection mechanism 16 and the light-receiving unit 18. However, the light-projecting unit 12 does not have to be rotated about the second axis P2 by the second deflection mechanism 20. For example, the light-projecting unit 12 may be supported by the casing 10 so as to be able to project measurement light onto the deflection mirror 28a along the second axis P2.

[0089] REFERENCE SIGNS LIST 10 Casing 12 Light-emitting section 14 Deflection device 16 First deflection mechanism 18 Light-receiving unit 20 Second deflection mechanism 22 Reference reflecting member 24 Signal processing section 28 Movable section 28a Deflection mirror 40 Housing 42 Light-receiving lens 44 Detector 44a Light-receiving element 44b Circuit board 70 Swing control section 70a Amplitude detection section 70b Amplitude control section 72 Selection section 74 Synchronization control section 80A, 80B Light-receiving section 100 Optical distance measuring device R1 First reference plane R2 Second reference plane V1 First field of view V2 Second field of view

Claims

1. A light-projecting unit that emits measurement light; a first deflection mechanism including a light-deflecting unit that deflects and reflects the measurement light emitted from the light-projecting unit, and having a movable unit that can swing around a first axis and a drive unit that drives the movable unit to swing; a plurality of light-receiving units each having a plurality of light-receiving elements arranged in a predetermined direction along the direction around the first axis, and receiving light reflected from an object from the measurement light with any of the light-receiving elements; a second deflection mechanism that drives and rotates at least the first deflection mechanism and the light-receiving unit around a second axis different from the first axis; and a control unit that controls the first deflection mechanism, the second deflection mechanism, the light-projecting unit, and the light-receiving unit to calculate the distance to the object based on the measurement light and the reflected light, wherein the measurement light is deflected and reflected by the light-deflecting unit, so that it scans one side and the other of a first reference plane that intersects with the second axis along the direction around the first axis, An optical distance measuring device, wherein the plurality of light receiving units include a first light receiving unit provided corresponding to a first field of view that includes an area on one side of the first reference plane within the scanning range of the measurement light along the direction around the first axis, and a second light receiving unit provided corresponding to a second field of view that includes an area on the other side of the first reference plane within the scanning range and is different from the first field of view, and the first light receiving unit and the second light receiving unit are arranged symmetrically with respect to a second reference plane that includes the direction around the first axis and includes the second axis.

2. An optical distance measuring device as described in claim 1, wherein one area obtained by dividing the scanning range into two by the first reference plane is the first field of view, and the other area obtained by dividing the scanning range into two by the first reference plane is the second field of view.

3. An optical distance measuring device as described in claim 1 or 2, wherein the first light receiving unit and the second light receiving unit are each optically designed to be commonly used and comprise a light receiving lens that focuses the reflected light, and the plurality of light receiving elements arranged in the specified direction that receive the reflected light focused by the light receiving lens, and are attached to the second deflection mechanism at an angle relative to each other so as to face the corresponding first field of view or second field of view.

4. An optical distance measuring device as described in claim 3, wherein the first light receiving unit and the second light receiving unit each have a housing that mounts the light receiving lens and the multiple light receiving elements to the second deflection mechanism, and the two housings define a space between them as a guide through which the measurement light passes as it is scanned in a direction around the first axis by the first deflection mechanism.

5. An optical distance measuring device as described in claim 1, wherein the first deflection mechanism comprises a fixed part supported by the second deflection mechanism so as to be rotatable around the second axis, and a beam part that supports the movable part on the fixed part, and the beam part is driven to rotate in torsion or oscillate in bending by the drive part, and functions as the first axis.

6. An optical distance measuring device as described in claim 1, further comprising a non-contact power supply unit having a power receiving unit arranged to rotate around the second axis as the second deflection mechanism rotates, and a power transmitting unit arranged opposite the power receiving unit on a common axis, wherein the non-contact power supply unit supplies power from the power transmitting unit to the power receiving unit.

7. An optical distance measuring device as described in claim 1, further comprising: a reference reflecting member onto which measurement light emitted from the light projecting unit and deflected and reflected by the optical deflecting unit is irradiated; and a swing control unit that controls the drive unit of the first deflection mechanism, wherein a control signal from the swing control unit is transmitted to the drive unit.

8. An optical distance measuring device as described in claim 7, wherein the reference reflecting member has an area with equal reflectivity along the second axis, and the swing control unit has an amplitude detection unit that detects the swing amplitude caused by the first deflection mechanism based on the reflected light received by the light receiving unit from the area with equal reflectivity of the reference reflecting member, and an amplitude control unit that controls the drive unit so that the swing amplitude detected by the amplitude detection unit becomes a predetermined swing amplitude.

9. An optical distance measuring device according to claim 8, wherein the driving section includes a driving piezoelectric element formed on the movable section, and the amplitude control section controls the voltage applied to the piezoelectric element.

10. An optical distance measuring device according to claim 8, wherein the driving section includes a driving coil formed in the movable section, and the amplitude control section controls the current applied to the coil.

11. An optical distance measuring device as described in claim 1, which is provided with a synchronization control unit that adjusts the rotation period of the second deflection mechanism and / or the measurement period using the measurement light emitted from the light projecting unit in synchronization with the oscillation period of the movable unit.

12. An optical distance measuring device as described in claim 7, further comprising a light adjusting unit that adjusts the intensity or light emission interval of the measurement light emitted from the light projecting unit based on the reflected light from the reference reflecting member received by the light receiving unit.

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