JP2013130422A - Laser radar - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a laser radar capable of properly detecting a distance to an object even when the distance is changed according to an environment.SOLUTION: A lase radar 300 comprises: a laser source 401 for emitting a laser beam; a beam-shaping lens 402 for shaping the laser beam; a mirror actuator 1 for scanning a target region with a laser beam having passed through the beam-shaping lens; a light-receiving lens 502 for collecting light reflected by the target region; and a light detector 503 for receiving the reflected light collected by the light-collecting element. A laser unit 400 includes a mechanism for adjusting a distance between the laser source 401 and the beam-shaping lens 402.

Description

  The present invention relates to a laser radar that detects the state of a target area based on reflected light when the target area is irradiated with laser light.

  In recent years, laser radar has been used for security purposes such as intrusion detection into buildings. In general, radar radar scans a laser beam within a target area, and detects the presence or absence of an object at each scan position from the presence or absence of reflected light at each scan position. Further, the distance to the object at each scan position is detected based on the required time from the laser light irradiation timing at each scan position to the reflected light reception timing (Patent Document 1).

  The reflected light from the target area is received by a photodetector in the laser radar. A signal having a magnitude corresponding to the amount of received light is output from the photodetector. When this signal exceeds a predetermined threshold, it is determined that an object exists at the scan position. Further, the timing at which this signal exceeds the threshold is set as the timing of receiving reflected light, and the distance to the object at the scan position is measured as described above.

JP 2009-14698 A

  In the above configuration, the laser beam is emitted to the target area so as to be focused at a predetermined distance in a predetermined environment. However, the object in the target area may be positioned farther than the focal length in accordance with changes in the environment such as the size of the room. In this case, when laser light is irradiated to an object at a distance longer than the focal length, the beam shape of the laser light becomes unclear due to aberration. As a result, the intensity of the reflected light received by the photodetector decreases, and the signal having a magnitude corresponding to the amount of received light does not exceed the threshold value, and there is a possibility that the distance cannot be acquired properly.

  The present invention has been made in view of such problems, and an object of the present invention is to provide a laser radar that can appropriately acquire a distance even if the distance to an object changes according to the environment.

  A laser radar according to a main aspect of the present invention scans a laser light source that emits laser light, a beam shaping lens that shapes a beam shape of the laser light, and the laser light that has passed through the beam shaping lens in a target region. A scanning unit; a condensing element that condenses the reflected light reflected in the target region; a photodetector that receives the reflected light collected by the condensing element; the laser light source; and the beam shaping lens. And a focus adjustment unit that adjusts the distance between the first and the second.

  ADVANTAGE OF THE INVENTION According to this invention, even if the distance to an object changes according to an environment, the laser radar which can acquire a distance appropriately can be provided.

The effects and significance of the present invention will become more apparent from the following description of embodiments.
However, the embodiment described below is merely an example when the present invention is implemented, and the present invention is not limited to what is described in the following embodiment.

It is a figure which shows the disassembled perspective view of the mirror actuator which concerns on embodiment. It is a figure which shows the assembly process of the mirror actuator which concerns on embodiment. It is a figure which shows the assembly process of the mirror actuator which concerns on embodiment. It is a figure which shows the assembly process of the mirror actuator which concerns on embodiment. It is a figure which shows the assembly process of the mirror actuator which concerns on embodiment. It is a figure which shows the assembly process of the mirror actuator which concerns on embodiment. It is a figure which shows the mirror actuator which concerns on embodiment. It is a figure which shows the structure of the laser radar which concerns on embodiment. It is a figure which shows the structure of the laser unit which concerns on embodiment. It is a figure which shows the disassembled perspective view of the light-receiving unit which concerns on embodiment. It is a figure which shows the assembly process of the light reception unit which concerns on embodiment. It is a figure which shows the assembly process of the laser radar which concerns on embodiment. It is a figure which shows the structure of the laser radar which concerns on embodiment. It is a figure explaining the structure and effect | action of the servo optical system which concerns on embodiment. It is a figure which shows the circuit structure of the laser radar which concerns on embodiment. It is a figure explaining the scanning control of the laser beam which concerns on embodiment. It is a figure which shows the focal distance of the laser beam and object distance which concern on embodiment. It is a figure which shows the beam shape according to the distance of the object of the laser beam which concerns on embodiment. It is a figure which shows the example of the focus adjustment of the laser unit which concerns on embodiment.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

  FIG. 1 is an exploded perspective view of a mirror actuator 1 according to the present embodiment. As illustrated, the mirror actuator 1 includes an inner unit 10 and an outer unit 20.

  FIG. 2 is an exploded perspective view of the inner unit 10 of the mirror actuator 1. As illustrated, the inner unit 10 includes an inner unit frame 11, a pan shaft 12, pan magnet units 13, 14, tilt magnet units 15, 16, pan coil units 17, 18, and suspension wires 19a to 19d. It has.

  The inner unit frame 11 is a frame member that instructs the pan shaft 12 to be rotatable. The inner unit frame 11 has a rectangular outline in a front view. The inner unit frame 11 is formed with a shaft hole 11a arranged on the left and right and a shaft hole 11b arranged on the top and bottom. The shaft hole 11a is disposed at the center position of the left and right side surfaces, and the shaft hole 11b is disposed at the center of the upper and lower side surfaces. A bearing 11c is fitted into the shaft hole 11a, and a bearing 11d is fitted into the shaft hole 11b.

  The pan shaft 12 is formed with a hole 12a for passing a lead wire for electrically connecting the pan coils 171 and 181 (see FIG. 3) and the LED 122, and a step portion 12b for fitting the mirror 123 therein. In addition, the inside of the pan shaft 12 is hollow in order to pass a lead wire that electrically connects the pan coils 171 and 181 and the LED 122. As will be described later, the pan shaft 12 is used as a rotating shaft that rotates the mirror 123 in the Pan direction.

  An LED 122 is mounted on the back side of the pan shaft 12. The LED 122 is a diffusion type (wide directional type) and can diffuse light over a wide range. As will be described later, the diffused light from the LED 122 is used to detect the scanning position in the target region of the scanning laser light. The LED 122 is attached to the LED substrate 121. The LED substrate 121 is attached to the pan shaft 12 from the rear direction.

  The pan magnet units 13 and 14 are mounted on the upper and lower surfaces of the inner unit frame 11, respectively, and the tilt magnet units 15 and 16 are mounted on the left and right side surfaces of the inner unit frame 11, respectively. Further, the pan coil units 17 and 18 are respectively mounted on the upper and lower ends of the pan shaft 12. Electromagnetic drive generated between the pan magnets 131 and 141 and the pan coils 171 and 181 when a current flows into the pan coils 171 and 181 (not shown in FIG. 2, see FIG. 3) arranged in the pan coil units 17 and 18. The pan shaft 12 is driven in the rotational direction by the force. Furthermore, suspension wire fixing substrates 191 and 192 for fixing the ends of the suspension wires 19a to 19d are mounted on the lower surface of the inner unit frame 11.

  FIG. 3 is a diagram showing a configuration of the pan coil unit 17. 3A is an exploded perspective view when the pan coil unit 17 is viewed from the lower side, FIG. 3B is a perspective view when the pan coil holder 172 is viewed from the upper side, and FIG. It is a perspective view when the pan coil unit 17 is seen from the upper side. Since the configuration of the pan coil unit 18 is substantially the same as that of the pan coil unit 17, the numbers of the respective parts of the pan coil unit 17 and the numbers of the respective parts of the pan coil unit 18 corresponding thereto are given in FIG. ing. Here, for convenience, the pan coil unit 17 will be described.

  With reference to FIG. 3A, the pan coil unit 17 includes a pan coil 171, a pan coil holder 172, a yoke 173, and a suspension wire fixing substrate 174.

  The pan coil holder 172 is made of a resin material. The pan coil holder 172 is provided with four pan coil mounting portions 172a. The pan coil mounting part 172a has a structure in which a wall is formed around a substantially fan-shaped opening that penetrates vertically. Each of the four pan coil mounting portions 172a is fixed so that the pan coil 171 is wound along the wall. The four pan coils 171 have the same substantially fan shape. When the four pan coils 171 are respectively mounted on the corresponding pan coil mounting portions 172a, the outline of the entire pan coil 171 becomes a substantially circular shape in plan view. In this state, the four pan coils 171 are evenly arranged in the circumferential direction so that the fan-shaped sides are adjacent to each other. The four pan coils 171 are connected in series, and the winding direction is adjusted so that an electromagnetic driving force in the same rotational direction is generated in each pan coil 171 by flowing current in a state where the mirror actuator 1 is assembled. Has been.

  In addition, a shaft hole 172 b for passing the end of the pan shaft 12 is provided in the center of the pan coil holder 172. Further, a shaft hole 173 a for allowing the end 12 d of the pan shaft 12 to pass is provided in the center of the yoke 173. The yoke 173 enhances the action of the magnetic field of the opposing pan magnet 131.

  Further, the corner of the pan coil holder 172 is raised in a trapezoidal shape, and two wire holes 172c for passing the suspension wires 19a and 19b and two wire holes 172d for passing the suspension wires 19c and 19d are passed through this portion. Is formed. The wire holes 172c and 172d penetrate vertically. The suspension wire fixing substrate 174 has a rectangular thin plate shape.

  The suspension wire fixing substrate 174 is made of glass epoxy resin. The suspension wire fixing substrate 174 has two terminal holes 174b for passing the suspension wires 19a and 19b and two terminal holes 174c for passing the suspension wires 19c and 19d at positions corresponding to the wire holes 172c and 172d. Is formed. The terminal holes 174b and 174c penetrate vertically. Further, as shown in FIG. 3C, recesses for placing solder are formed around the terminal holes 174b and 174c on the upper surface of the suspension wire fixing substrate 174.

  Moreover, as shown in FIG.3 (b), the cylindrical convex parts 172e and 172f are formed in the upper surface of the pan coil holder 172. As shown in FIG. Two holes 173b are formed in the yoke 173 at positions corresponding to the convex portions 172e. The yoke 173 is positioned in the pan coil holder 172 by passing the hole 173b through the convex portion 172e. In this state, the yoke 173 is bonded and fixed to the upper surface of the pan coil holder 172.

  In the suspension wire fixing substrate 174, two holes 174a are formed at positions corresponding to the convex portions 172f. The suspension wire fixing substrate 174 is positioned with respect to the pan coil holder 172 by passing the hole 174a through the convex portion 172f. In this state, the suspension wire fixing substrate 174 is bonded and fixed to the upper surface of the pan coil holder 172. Thereby, the pan coil unit 17 shown in FIG. 3C is completed.

  In this state, the position of the shaft hole 172 b of the pan coil holder 172 is matched with the position of the shaft hole 173 a of the yoke 173. Further, the position of the wire hole 172c of the pan coil holder 172 is aligned with the position of the terminal hole 174b of the suspension wire fixing substrate 174, and the position of the wire hole 172d of the pan coil holder 172 is the position of the terminal hole 174c of the suspension wire fixing substrate 174. To fit the position.

  The pan coil unit 18 is configured in substantially the same manner as the pan coil unit 17. However, since the suspension wires 19a to 19d are not passed through the suspension wire fixing substrate 184 of the pan coil unit 18, no wire holes are provided in the pan coil holder 182, and the suspension wire fixing substrate 184 has terminals. There is no hole.

  Referring to FIG. 2, when assembling inner unit 10, first, pan shaft 12 is passed through shaft hole 11 b and accommodated in inner unit frame 11. Then, the mirror 123 is fitted into the step 12 b of the pan shaft 12, and the bearings 11 d are attached to the shafts at both ends of the pan shaft 12. In this state, the two bearings 11 d are fitted into the shaft holes 11 b formed in the inner unit frame 11. In addition, two bearings 11 c for the tilt shafts 25 and 26 (see FIG. 1) are fitted into shaft holes 11 a formed in the inner unit frame 11. Thereby, the assembly shown in FIG. 4A is completed. 4A to 4D, the mirror 123 is omitted for convenience. In the state of FIG. 4A, the suspension wire fixing substrates 191 and 192 are mounted on the lower surface of the inner unit frame 11 as described above (not shown).

Thereafter, as shown in FIG. 4B, the pan magnet unit 13 is mounted on the upper surface of the inner unit frame 11. The pan magnet unit 13 is configured by bonding a ring-shaped pan magnet 131 (see FIG. 2) to a pan magnet holder 132. The pan magnet 131 is equally divided into four magnetic pole regions in the circumferential direction. The magnetic poles of adjacent magnetic pole regions are different from each other. When the pan magnet unit 13 is mounted, the screws 13 a and 13 b are screwed onto the upper surface of the inner unit frame 11 with the pan magnet holder 132 fitted in the groove on the upper surface of the inner unit frame 11. Similarly, a pan magnet unit 14 having the same configuration as that of the pan magnet unit 13 is fixed to the lower surface of the inner unit frame 11 by screws 14a and 14b (see FIG. 2).

  Then, as shown in FIG. 4C, tilt magnet units 15 and 16 are attached to the left and right side surfaces of the inner unit frame 11. The tilt magnet units 15 and 16 are configured by bonding ring-shaped tilt magnets 151 and 161 (see FIG. 2) to tilt magnet holders 152 and 162, respectively. Each of the tilt magnets 151 and 161 is equally divided into four magnetic pole regions in the circumferential direction. The magnetic poles of adjacent magnetic pole regions are different from each other. When the tilt magnet unit 16 is mounted, the screws 16 a and 16 b are screwed onto the right side surface of the inner unit frame 11 with the tilt magnet holder 162 fitted in a groove formed on the right side surface of the inner unit frame 11. . Similarly, the tilt magnet unit 15 is fixed to the inner unit frame 11 with screws 15a and 15b (see FIG. 2).

  Next, the pan coil units 17 and 18 are respectively attached to both ends of the pan shaft 12 so as to be fitted to both ends of the pan shaft 12. Thereby, the assembly of FIG. 4D is completed. In this state, the pan coil units 17 and 18 can rotate integrally with the pan shaft 12. Note that the pan coils 171 and 181 of the pan coil units 17 and 18 are arranged such that an electromagnetic driving force in the rotational direction is generated on the pan shaft 12 when current flows.

  In this state, as shown in FIG. 5B, the suspension wires 19a and 19b are connected to the suspension wire fixing substrate 191 via the terminal holes 174b of the suspension wire fixing substrate 174 and the wire holes 172c of the pan coil holder 172. It passes through the terminal hole 191a. Similarly, it is passed through the terminal hole 192a of the suspension wire fixing substrate 192 through the terminal hole 174c of the suspension wire fixing substrate 174 and the wire hole 172d of the pan coil holder 172. The suspension wires 19a to 19d are soldered to the suspension wire fixing substrates 174, 191 and 192 together with the pan coils 171 and 181 and the lead wires for supplying current to the LEDs 122, respectively. In addition to the terminal holes 191a and 192a, terminal holes 191b and 192b are formed in the suspension wire fixing substrates 191 and 192. The terminal hole 191a and the terminal hole 191b are electrically connected by a conductive pattern, and the terminal hole 192a and the terminal hole 192b are electrically connected by a conductive pattern.

  Thus, as shown in FIG. 5, the assembly of the inner unit 10 is completed. FIG. 5A is a perspective view of the assembled inner unit 10 viewed from the front side, and FIG. 5B is a perspective view of the assembled inner unit 10 viewed from the rear side. In this state, the mirror 123 can rotate around the pan shaft 12 in the Pan direction. The pan coil units 17 and 18 rotate in the Pan direction as the mirror 123 rotates in the Pan direction. On the other hand, since the suspension wire fixing substrates 191 and 192 are fixed to the lower surface of the inner unit 10, they do not rotate in the Pan direction as the mirror 123 rotates in the Pan direction.

  Returning to FIG. 1, the outer unit 20 includes an actuator frame 21, tilt coil units 22, 23, a servo unit 24, tilt shafts 25, 26, and suspension wires 27a to 27d.

Referring to FIG. 6, the actuator frame 21 is composed of a frame member whose front is open. In the center of the left and right side surfaces of the actuator frame 21, shaft holes 21a and 21d for allowing the tilt shafts 25 and 26 to pass are formed. Screw holes 21b, 21c, 21e, and 21f for fixing the tilt coil units 22 and 23 are formed on the left and right side surfaces of the actuator frame 21. In addition, an opening 21g for passing the pinhole box 244 of the servo unit 24 and screw holes 21h and 21i for fixing the servo unit 24 are formed on the rear side surface of the actuator frame 21. Further, screw holes 21j and 21k for fixing the mirror actuator 1 to a holding frame 310 to be described later are formed on the rear side surface of the actuator frame 21.

  FIG. 6B is a diagram illustrating a configuration of the tilt coil unit 22. Since the configuration of the tilt coil unit 23 is the same as that of the tilt coil unit 22, the numbers of the respective parts of the tilt coil unit 22 and the numbers of the respective parts of the tilt coil unit 23 corresponding thereto are given in FIG. Yes. Here, for convenience, the tilt coil unit 23 will be described.

  With reference to FIG. 6B, the tilt coil unit 22 includes a tilt coil 221 and a tilt coil holder 222.

  The tilt coil holder 222 is made of a resin material. The tilt coil holder 222 is provided with four tilt coil mounting portions 222a. The tilt coil mounting portion 222a has a configuration in which a wall is formed around a substantially fan-shaped opening penetrating vertically. A tilt coil 221 is fixed to each of the four tilt coil mounting portions 222a so as to be wound along the wall. The four tilt coils 221 have substantially the same fan shape. When the four tilt coils 221 are respectively mounted on the corresponding tilt coil mounting portions 222a, the entire outline of the tilt coil 221 becomes a substantially circular shape in plan view. In this state, the four tilt coils 221 are evenly arranged in the circumferential direction so that the fan-shaped sides are adjacent to each other. The four tilt coils 221 are connected in series, and an electric current flows in the assembled state of the mirror actuator 1, so that an electromagnetic driving force in the same rotational direction is generated between each tilt coil 221 and the tilt magnet unit 15. The winding direction is adjusted so as to generate.

  In the center of the tilt coil holder 222, a circular shaft hole 222b through which the tilt shaft 25 is passed is provided. Further, screw holes 222 c and 222 d for fixing to the actuator frame 21 are formed at both ends of the tilt coil holder 222.

  The tilt coil unit 23 is configured in the same manner as the tilt coil unit 22. Here, detailed description of each part is omitted.

  Referring to FIG. 6C, the servo unit 24 includes a PSD substrate 241, a PSD 242, a band pass filter 243, and a pinhole box 244.

  Two screw holes 241 a and 241 b for fixing the PSD substrate 241 to the actuator frame 21 are formed in the PSD substrate 241. Two terminal holes 241c (not shown in FIG. 6C, see FIG. 7B) for passing the suspension wires 27a and 27b are formed on the back surface of the PSD substrate 241. Further, two terminal holes 241d (not shown in FIG. 6C, see FIG. 7B) for passing the suspension wires 27c and 27d are formed on the back surface of the PSD substrate 241. A PSD 242 is mounted on the PSD substrate 241. The PSD 242 outputs a signal corresponding to the light receiving position of the servo light.

The bandpass filter 243 transmits only light in the wavelength band emitted from the LED 122 and removes stray light in other wavelength bands. The band pass filter 243 is attached to the surface of the PSD 242 and is bonded and fixed.

  As shown in FIG. 6D, the pinhole box 244 has a hollow inside, and a pinhole 244a is formed at the center. The pinhole 244a transmits a part of the diffused light emitted from the LED 122. The pinhole box 244 is made of a light shielding material and prevents stray light other than light transmitted through the pinhole 244a from entering the PSD 242. The pinhole box 244 is attached to the PSD substrate 241 and bonded and fixed.

  Returning to FIG. 6A, when the outer unit 20 is assembled, the screws 22a and 22b are screwed into the screw holes 21b and 21c through the screw holes 222c and 222d. Thereby, the tilt coil unit 22 is fixed to the actuator frame 21. Similarly, the screws 23a and 23b are screwed into the screw holes 21e and 21f through the screw holes 232c and 232d. Thereby, the tilt coil unit 23 is fixed to the actuator frame 21.

  Next, the screws 24a and 24b are screwed into the screw holes 21h and 21i through the screw holes 241a and 241b. Thereby, the servo unit 24 is fixed to the actuator frame 21. Thus, the structure shown in FIG. 1 is assembled.

  Referring to FIG. 1, suspension wires 27a to 27d are made of phosphor bronze, beryllium copper or the like, have excellent conductivity, and have spring properties. The suspension wires 27a to 27d have a rectangular cross section. The suspension wires 27 a to 27 d have the same shape and characteristics as each other, and are used for supplying current to the pan coils 171 and 181 and the LED 122. The suspension wires 27a to 27d have a shape curved backward in a normal state.

  When the inner unit 10 and the outer unit 20 are assembled, the inner unit 10 is first accommodated in the outer unit 20. From the left, the step portion 25a of the tilt shaft 25 is passed through the shaft hole 21a (see FIG. 6A) of the actuator frame 21, and the step portion 25b is passed through the bearing 11c of the inner unit frame 11 (see FIG. 2). ). Thereafter, the magnet holder 251 for the magnetic spring is passed through the step portion 25c of the tilt shaft 25, and is fixed by adhesion.

  Similarly, from the right, the step portion 26a of the tilt shaft 26 is passed through the shaft hole 21d of the actuator frame 21, and the step portion 26b is passed through the bearing 11c (see FIG. 2) of the inner unit frame 11. Then, the magnet holder 261 for magnetic spring is passed through the step portion 26c of the tilt shaft 26 and is fixedly bonded.

  In this state, the tilt shafts 25 and 26 are rotated, and the positions of the magnetic spring magnets 252 and 262 in the rotational direction are adjusted. Specifically, with the inner unit 10 standing upright in the vertical direction, each magnetic pole region of the magnetic spring magnets 252 and 262 is in a position directly opposite to the corresponding magnetic pole region of the tilt magnets 151 and 161. The positions of the magnets 252 and 262 are adjusted. After such adjustment is completed, the tilt shafts 25 and 26 are bonded and fixed to the actuator frame 21.

  Thereby, even if the inner unit frame 11 rotates in the tilt direction, the tilt shafts 25 and 26 and the magnets for magnetic springs 252 and 262 are fixed so as not to rotate. On the other hand, the tilt magnets 151 and 161 rotate integrally with the inner unit frame 11.

  When the inner unit frame 11 is not rotating, the position of the boundary between the magnetic spring magnets 252 and 262 and the position of the boundary between the tilt magnets 151 and 161 are the same. Further, the polarities of the respective regions of the magnetic spring magnets 252 and 262 are different from the polarities of the respective regions of the opposing tilt magnets 151 and 161. Accordingly, the tilt magnets 151 and 161 are attracted in the right direction and the left direction, respectively, whereby a right direction force and a left direction force act on the inner unit frame 11. These two forces are balanced with each other. Therefore, the inner unit frame 11 is supported by the actuator frame 21 without being urged in the left or right direction.

  Thus, when the inner unit 10 is rotatably attached to the outer unit 20, as shown in FIG. 7B, one end of the suspension wires 27a and 27b is passed through the terminal hole 191b of the suspension wire fixing substrate 191. Soldered. Further, the other ends of the suspension wires 27a and 27b are passed through the two terminal holes 241c of the PSD substrate 241 and soldered.

  Similarly, one end of each of the suspension wires 27c and 27d is passed through the terminal hole 192b of the suspension wire fixing substrate 192 and soldered. The other ends of the suspension wires 27c and 27d are passed through the two terminal holes 241d of the PSD board 241 and soldered. When the mirror surface of the mirror 123 is perpendicular to the horizontal direction as shown in FIG. 7A, the suspension wires 27a to 27d are connected to the terminal holes 191b and 192b without being substantially deformed from the normal state. It has a shape curved backward so as to connect 241c and 241d. Thereby, the suspension wires 27a to 27d can have a length necessary when the inner unit frame 11 rotates in the tilt direction without applying unnecessary force to the inner unit frame 11 as much as possible. Further, current is supplied to the pan coils 171 and 181 and the LED 122 attached to the inner unit frame 11 by the suspension wires 27a to 27d.

  In addition, although not shown, a conductive wire is directly connected to the tilt coils 221 and 231 from the PSD substrate 241 and supplied with current. Since the tilt coils 221 and 231 are attached to the actuator frame 21 that does not rotate, even if the conductive wire is directly connected, the rotation of the mirror 123 is not affected.

  Thus, the assembly of the mirror actuator 1 is completed. FIG. 7A is a perspective view of the mirror actuator 1 viewed from the front, and FIG. 7B is a perspective view of the mirror actuator 1 viewed from the rear. In this state, the inner unit frame 11 can be rotated around the tilt shafts 25 and 26 in the tilt direction. The pan coil units 17 and 18 and the suspension wire fixing substrates 191 and 192 rotate in the tilt direction as the inner unit frame 11 rotates in the tilt direction.

  In the assembled state shown in FIG. 7, when a current is passed through the pan coils 171, 181, the pan shaft 12 is rotated together with the pan coil units 17, 18 by the electromagnetic driving force generated in the pan coils 171, 181 and the pan magnets 131, 141, As a result, the mirror 123 rotates in the Pan direction about the pan shaft 12.

When the mirror 123 rotates in the Pan direction, the pan coil units 17 and 18 rotate integrally, and the suspension wire fixing substrates 191 and 192 do not rotate. Therefore, the suspension wires 19a and 19b and the suspension wires 19c and 19d are respectively positioned at the twisted positions around the pan shaft 12 while being pulled in the longitudinal direction. At this time, since the suspension wires 19a to 19d do not expand and contract in the longitudinal direction, the suspension wire fixing substrates 191 and 192 having flexibility are pulled upward. In this way, due to the spring properties of the suspension wires 19a to 19d and the suspension wire fixing substrates 191 and 192, a torque is generated in the direction opposite to the Pan direction of the mirror 123 around the pan shaft 12. This torque has a predetermined value that can be calculated based on the spring constants of the suspension wires 19a to 19d and the suspension wire fixing substrates 191 and 192 and the rotational position of the mirror 123 around the pan shaft 12. Thus, when the mirror 123 is rotated in the Pan direction, a reverse torque is always generated. Therefore, when the current application to the pan coils 171 and 181 is stopped, the mirror 123 returns to the position before the rotation. It is.

  In the assembled state shown in FIG. 7, when an electric current is passed through the tilt coils 221 and 231, the inner unit frame 11 is tilted together with the pan coil units 17 and 18 by the electromagnetic driving force generated in the tilt coils 221 and 231 and the tilt magnets 151 and 161. The mirror 123 rotates in the tilt direction about the shafts 25 and 26, thereby rotating the mirror 123 in the tilt direction.

  When the inner unit frame 11 rotates in the tilt direction, the tilt magnet 151 rotates with the inner unit frame 11, but the magnetic spring magnet 252 does not rotate because it is fixed to the tilt shaft 25. For this reason, the area division position of the tilt magnet 151 and the area division position of the magnetic spring magnet 252 are shifted in the circumferential direction. Accordingly, a part of the N pole region of the tilt magnet 151 faces a part of the N pole region of the magnetic spring magnet 252, and a part of the S pole region of the tilt magnet 151 is set to the magnetic spring magnet 252. It faces a part of the S pole region. For this reason, a magnetic force that pulls the tilt magnet 151 back to the position before the rotation is generated in each region of the tilt magnet 151. Thereby, torque (drag) toward the tilt neutral position is applied to the inner unit frame 11. This torque (drag) is a predetermined value that can be calculated by the strength of the magnetic force generated between the tilt magnet 151 and the magnetic spring magnet 252 and the rotational position of the inner unit frame 11.

  Thus, when the mirror 123 is rotated integrally with the inner unit frame 11 from the tilt neutral position, a reverse torque is always generated. Therefore, when the application of current to the tilt coils 221 and 231 is stopped, the mirror 123 is stopped. Is returned to the tilt neutral position.

  FIG. 8 is a schematic view of the inside of the laser radar 300 with the mirror actuator 1 mounted as seen through from the side.

  Referring to FIG. 8, laser radar 300 includes mirror actuator 1, housing 301, projection / light receiving window 302, laser unit 400, and light receiving unit 500.

  The housing 301 has a cubic shape and includes a base 301a and a cover 301b. The housing 301 accommodates the mirror actuator 1, the laser unit 400, and the light receiving unit 500 therein. A projection / light receiving window 302 is attached to the front surface of the housing 301.

  The projection / light receiving window 302 is made of a curved transparent plate having a curved surface. The projection / light receiving window 302 is made of a highly transparent material, and an antireflection film (AR coating) is attached to the incident surface and the output surface.

9A and 9B are cross-sectional views schematically showing a cross section when the laser unit 400 is cut along a plane (YZ plane) passing through the central axis of the laser unit 400 and perpendicular to the base 301a of the housing 301. It is. 9A shows the laser unit 400 in a state where each member is disassembled, and FIG. 9B shows the laser unit 400 in a state where each member is assembled. FIG. 9C is a perspective view of the laser unit 400 in a state where the respective members are assembled as viewed from the front.

  The laser unit 400 includes a laser light source 401, a beam shaping lens 402, a laser holder 411, a fastening screw 412, a light transmission plate 413, and a lens holder 414.

  The laser light source 401 emits laser light having a wavelength of about 900 nm. The laser light source 401 is a CAN package type laser light source including a CAN 401b on a base 401a. The laser light source 401 is a high-power broad area semiconductor laser having a stripe width that is long in the vertical direction.

  The beam shaping lens 402 is an aspheric lens, and converges the emitted laser light so that the emitted laser light has a predetermined shape in the target area. For example, the beam shape is set so that the beam shape in the target area (in the present embodiment, set at a position about 15 m forward from the projection / light receiving window 302) is a substantially elliptical shape with a length of about 2 m and a width of about 0.2 m. A shaping lens 402 is designed.

  The laser holder 411 is made of metal such as aluminum. The laser holder 411 has a substantially cylindrical shape with different outer diameters at the front and rear. A large-diameter portion 411a is formed in the front, and a small-diameter portion 411b having a smaller diameter than the large-diameter portion 411a is formed in the rear. The outer periphery of the large-diameter portion 411a is knurled to prevent slipping when screwed onto the retaining screw 412 (see FIG. 9C). A screw hole 411c into which a holding screw 411d is screwed is formed in the upper portion of the large diameter portion 411a. The holding screw 411d has a flat tip, and the vertical height of the holding screw 411d is slightly larger than the thickness of the large diameter portion 411a. When the holding screw 411d is completely screwed into the screw hole 411c, the holding screw 411d penetrates the large diameter portion 411a and slightly protrudes into the opening 411f. A thread groove 411e is provided in a part of the rear side of the outer surface of the small diameter portion 411b.

  The laser holder 411 is formed with a circular opening 411f for accommodating the lens holder 414 and a circular opening 411g for accommodating the laser light source 401 therein. The diameter of the opening 411f is slightly larger than the outer diameter of the small diameter portion 414b of the lens holder 414, and the diameter of the opening 411g is slightly larger than the diameter of the base 401a of the laser light source 401. A screw groove 411h is provided in a part of the rear side of the inner surface of the opening 411f.

  Furthermore, between the opening 411f and the opening 411g, a ring-shaped step portion 411i having a smaller diameter than the openings 411f and 411g is formed, and a circular hole is formed inside the step portion 411i. The diameter of the hole inside the stepped portion 411 i is slightly larger than the diameter of the CAN 401 b of the laser light source 401. The laser light source 401 is fitted into the opening 411g from the rear until the front surface of the base 401a of the laser light source 401 contacts the step 411i of the laser holder 411. Thereby, the laser light source 401 is positioned with respect to the laser holder 411, and the laser light source 401 is bonded and fixed to the laser holder 411.

  The retaining screw 412 is formed of a metal such as aluminum, like the laser holder 411. The retaining screw 412 has a substantially cylindrical shape in which an opening 412a for accommodating the laser holder 411 is formed. The diameter of the opening 412a is slightly larger than the small diameter portion 411b of the laser holder 411. A screw groove 412b that meshes with the screw groove 411e of the laser holder 411 is provided in the opening 412a. The outer periphery of the retaining screw 412 is knurled to prevent slipping when screwed to the laser holder 411 (see FIG. 9C).

  The light transmission plate 413 is made of glass that can transmit light. An antireflection film is attached to the incident surface and the exit surface of the light transmission plate 413 in order to increase the transmittance of reflected light from the target region. The light transmission plate 413 has a substantially semicircular shape having a cut portion 413a whose upper portion is linearly cut when viewed from the front (see FIG. 9C). The light transmission plate 413 is slightly thick in the front-rear direction in order to stably hold the laser holder 411.

  Since the light transmission plate 413 guides the reflected light from the target area to a light receiving lens 502 (see FIG. 10) described later, even after the reflected light is refracted by the light transmission plate 413, the entire light receiving lens 502 has a lens surface. The diameter is such that the reflected light is incident. In the center of the light transmission plate 413, a circular opening 413b through which the laser holder 411 passes is formed. The diameter of the opening 413b is smaller than the large diameter portion 411a of the laser holder 411 and slightly larger than the small diameter portion 411b of the laser holder 411.

  The lens holder 414 is formed of a metal such as aluminum, like the laser holder 411. The lens holder 414 has a substantially cylindrical shape with different outer diameters at the front and rear. A large-diameter portion 414a is formed in the front, and a small-diameter portion 414b having a smaller diameter than the large-diameter portion 414a is formed in the rear. A screw groove 414c that meshes with the screw groove 411h of the laser holder 411 is provided in a part of the rear of the small diameter portion 414b. The lens holder 414 accommodates the beam shaping lens 402 therein, and has a circular opening 414 d for guiding the laser light emitted from the laser light source 401 to the beam shaping lens 402. The diameter in front of the opening 414d is slightly larger than the diameter of the beam shaping lens 402. A step 414e is formed in the opening 414d, and the diameter of the opening 414d at the step 414e is smaller than the diameter in front of the opening 414d. The beam shaping lens 402 is fitted into the opening 414d from the front until the peripheral portion of the rear surface of the beam shaping lens 402 abuts on the step 414e of the lens holder 414. In this state, the beam shaping lens 402 is bonded and fixed to the lens holder 414.

  When the laser unit 400 is assembled, first, the small diameter portion 411b of the laser holder 411 is passed through the opening 413b of the light transmission plate 413 from the front. Thereafter, the retaining screw 412 is screwed into the screw groove 411 e of the laser holder 411 from the rear so as to sandwich the light transmission plate 413. As a result, the light transmission plate 413 is sandwiched between the step between the large diameter portion 411 a and the small diameter portion 411 b of the laser holder 411 and the front surface of the retaining screw 412.

  In this state, the small diameter portion 414b of the lens holder 414 is passed through the opening 411f of the laser holder 411, and the lens holder 414 is screwed into the screw groove 411h of the laser holder 411. In this state, by rotating the lens holder 414, the position of the beam shaping lens 402 can be adjusted in the front-rear direction. Then, laser light is emitted from the laser light source 401, and the lens holder 414 is adjusted in the front-rear direction so that the laser light is focused at a predetermined distance (for example, 15 m). Specifically, first, a screen is set up at a target distance (approximately 15 m), and this screen is irradiated with laser light. In this state, the signal intensity from the photodetector 503 is monitored while the beam shaping lens 402 is moved in the front-rear direction. Then, the beam shaping lens 402 is positioned at a position where the monitored signal intensity is maximized. As a result, the focus of the beam shaping lens 402 is adjusted. After the focus adjustment of the beam shaping lens 402 is performed, a holding screw 411d is screwed into the screw hole 411c of the laser holder 411, and the lens holder 414 is pressed against the laser holder 411 by the flat tip portion of the holding screw 411d. Thereby, the lens holder 414 is fixed to the laser holder 411.

After the lens holder 414 is fixed to the laser holder 411, the beam shaping lens 4
The rotational position of 02 is adjusted. That is, the position of the beam shaping lens 402 in the rotation direction is adjusted so that the beam shape has a predetermined shape (vertically long) in the target region. For this reason, after the focus adjustment is performed as described above, the retaining screw 412 is once loosened, and the lens holder 414 can be rotated. In this state, the laser holder 411 is rotated to a position where the beam shape becomes a predetermined shape (longitudinal shape) in the target region, and then the retaining screw 412 is tightened. Thereby, the position adjustment of the beam shaping lens 402 in the rotation direction is completed.

  Thus, the laser unit 400 shown in FIGS. 9B and 9C is assembled.

  FIG. 10 is a perspective view of the laser unit 400 and the light receiving unit 500 in which each member is disassembled as viewed from the front. FIG. 11A is a perspective view of the lens barrel 511 viewed from the rear, and FIG. 11B is a perspective view of the laser holder holding portion 512 viewed from the rear. FIG. 11C is a perspective view of a state in which the laser unit 400 is assembled to the light receiving unit 500 in a state where the respective members are assembled, as viewed from the front.

  Referring to FIG. 10, the light receiving unit 500 includes a band pass filter 501, a light receiving lens 502, a photodetector 503, a lens barrel 511, and a laser holder holding unit 512.

  The band pass filter 501 is composed of a dielectric multilayer film and transmits only light in the wavelength band of the emitted laser light. Note that the band-pass filter 501 has a simple film configuration because the reflected light is incident in a substantially parallel light state.

  The light receiving lens 502 is a Fresnel lens and collects light reflected from the target area. The Fresnel lens is a lens in which a convex lens is divided into concentric regions to reduce the thickness.

  The photodetector 503 is composed of an APD (avalanche photodiode) or a PIN photodiode, and is mounted on the circuit board 503a. The photodetector 503 outputs an electrical signal having a magnitude corresponding to the amount of received light to the circuit board 503a. The light receiving surface of the photodetector 503 is not divided into a plurality of regions, but is a single light receiving surface. Further, the light receiving surface of the photodetector 503 has a narrow vertical and horizontal width (for example, around 1 mm) in order to suppress the influence of stray light. Four screw holes 503b for fixing the circuit board 503a to the lens barrel 511 are formed in the circuit board 503a.

  The lens barrel 511 is formed of a resin material that does not transmit light. The lens barrel 511 is formed with an inclined portion 511a so that the reflected light from the target region and the emitted laser light are not shielded. In addition, the lens barrel 511 has an opening 511b formed in front to guide reflected light to the photodetector 503. The opening 511 b is slightly larger than the diameters of the bandpass filter 501 and the light receiving lens 502. As shown in FIG. 11A, the lens barrel 511 has an opening 511c having a diameter smaller than that of the opening 511b at the rear. The opening 511 c is slightly smaller than the diameters of the bandpass filter 501 and the light receiving lens 502. Returning to FIG. 10, a step 511d is provided between the opening 511b and the opening 511c. Further, three screw holes 511e for fixing the laser holder holding portion 512 are formed on the front surface of the lens barrel 511. Further, two screw holes 511f for fixing to a holding frame 310 described later are formed on the left side surface of the lens barrel 511. Similarly, as shown in FIG. 11A, on the right side surface of the lens barrel 511, two screw holes 511g for fixing to a holding frame 310 described later are formed. Further, four screw holes 511h for fixing the circuit board 503a are formed on the back surface of the lens barrel 511.

The laser holder holding portion 512 is formed of a resin material or the like that does not transmit light, like the lens barrel 511. The laser holder holding portion 512 has a substantially semi-shaped opening 512a at the center in front view. The diameter of the opening 512 a is slightly larger than the diameter of the light transmission plate 413 of the laser unit 400. A step portion 512b is formed behind the opening 512a. Further, notches 512c are formed at the left and right upper ends of the opening 512a. Further, grooves 512d extending from the front direction to the rear direction are formed in the lower left corner, the upper right corner, and the lower right corner of the laser holder holding portion 512, and screw holes 512e are respectively formed behind the grooves 512d. (See FIG. 11B).

  When the light receiving unit 500 is assembled, first, the band-pass filter 501 and the light receiving lens 502 are attached to the opening 511b from the front so as to contact the step 511d. Thereafter, the circuit board 503a of the photodetector 503 is applied to the rear surface of the lens barrel 511 from the rear, and the four screw holes 503b of the circuit board 503a and the four screw holes 511h of the lens barrel 511 (see FIG. 11A). ). In this state, the four screws 503c are screwed into the four screw holes 511h of the lens barrel 511 through the four screw holes 503b. As a result, the photodetector 503 is attached to the lens barrel 511.

  Next, the back surface of the laser holder holding portion 512 is pressed against the front surface of the lens barrel 511 from the front, and the three screw holes 512e of the laser holder holding portion 512 are aligned with the three screw holes 511e of the lens barrel 511. In this state, the screw 512f is screwed into the screw hole 511e of the lens barrel 511e through the screw hole 512e. Thereby, the laser holder holding part 512 is fixed to the lens barrel 511.

  Thereby, the assembly of the light receiving unit 500 is completed. Thereafter, the laser unit 400 is passed from the front through the opening 512a of the laser holder holding part 512, and the light transmission plate 413 is pressed so as to contact the step part 512b. In this state, an adhesive is introduced from the notch 512c, and the light transmission plate 413 is bonded and fixed to the laser holder holding portion 512.

  In this way, the structure shown in FIG. 11C is assembled.

  FIG. 12 is an exploded perspective view of the laser radar 300 with the cover 301b of the housing 301 removed. The mirror actuator 1 is not shown, and the laser unit 400 and the light receiving unit 500 are shown in an assembled state.

  Referring to FIG. 12, holding frame 310 is a frame member mounted on base 301 a, and flat plate portions 311 and 312 for holding lens barrel 511 and an actuator holding portion for holding mirror actuator 1. 313 is provided.

  The flat plate portion 311 has a flat plate shape extending in the Y-axis direction, and moves forward (Z-axis positive direction) from the Y-axis positive direction in the in-plane direction of the YZ plane in a direction approaching the Z-axis positive direction (for example, An inclined portion 311a that is inclined at 30 degrees is formed. The flat plate portion 311 is formed with two screw holes 311b for fixing the lens barrel 511 and four screw holes 311c for fixing the circuit board 401c to which the laser light source 401 is electrically connected. Yes. Similarly, the flat plate portion 312 is a flat plate formed with an inclined portion 312a that is inclined at a predetermined angle (for example, 30 degrees) in a direction approaching the positive Z-axis direction from the positive Y-axis direction to the in-plane direction of the YZ plane. . The flat plate portion 312 is formed with two screw holes 312b for fixing the lens barrel 511 and four screw holes 312c for fixing a circuit board 600 described later.

The actuator holding portion 313 has a flat plate shape extending in the Y-axis direction, and in the in-plane direction of the YZ plane from the Y-axis positive direction to the rear (Z-axis negative direction) in a direction approaching the Z-axis negative direction (for example, , 15 degrees), inclined portions 313a and 313e are formed. The actuator holding portion 313 is formed with a flange portion 313b extending in the positive direction of the X axis in parallel with the inclined portion 313a. A screw hole 313c for fixing the mirror actuator 1 is formed in the flange portion 313b. Similarly, the actuator holding portion 313 is formed with a flange portion 313f extending in the negative X-axis direction in parallel with the inclined portion 313e. The flange portion 313f has a screw hole 313g for fixing the mirror actuator 1. Is formed.

  The circuit board 401c is a circuit board for electrically connecting the laser light source 401 (see FIG. 9A). The circuit board 401c is formed with four screw holes 401d for fixing to the flat plate portion 311.

  The circuit board 600 includes a CPU, a memory, and the like, and includes a circuit board 401c for the laser light source 401, a circuit board 503a for the photodetector 503 (see FIG. 10), and a PSD board 241 of the mirror actuator 1 (see FIG. 7). And electrically connected.

  When the laser radar 300 is assembled, first, the lens barrel 511 is accommodated between the flat plate portion 311 and the flat plate portion 312, and the two screw holes 511 f of the lens barrel 511 are aligned with the two screw holes 311 b of the flat plate portion 311. Two screw holes 511g (see FIG. 11A) of 511 are aligned with the two screw holes 312b of the flat plate portion 312. In this state, the two screws 311d are screwed into the two screw holes 511f through the two screw holes 311b. Similarly, two screws 312d are screwed into two screw holes 511g (see FIG. 11A) via two screw holes 312b. Accordingly, the light receiving unit 500 and the laser unit 400 are attached to the holding frame 310 so as to be inclined at a predetermined angle (for example, 60 degrees) so as to approach the negative Z-axis direction in the in-plane direction of the YZ plane from the positive Y-axis direction. It is done. In this state, the inclined portion 511a of the lens barrel 511 is parallel to the Z axis.

  Next, returning to FIG. 12, the four screw holes 401 d of the circuit board 401 c are aligned with the four screw holes 311 c of the flat plate portion 311. In this state, the four screws 401e are screwed into the four screw holes 311c through the four screw holes 401d. As a result, the circuit board 401 c is attached to the holding frame 310. Similarly, the four screw holes 600a of the circuit board 600 are aligned with the four screw holes 312c of the flat plate portion 312. In this state, the four screws 600b are passed through the four screw holes 600a to four screw holes. Screwed onto 312c. Thereby, the circuit board 600 is attached to the holding frame 310.

  Thereafter, the screw hole 21j (see FIG. 7B) of the mirror actuator 1 is aligned with the screw hole 313c, and the screw hole 21k (see FIG. 7B) of the mirror actuator 1 is aligned with the screw hole 313g. In this state, the screw 313d is screwed into the screw hole 21j (see FIG. 7B) of the mirror actuator 1 through the screw hole 313c, and the screw 313h is screwed into the mirror actuator 1 through the screw hole 313g. Screwed into the screw hole 21k (see FIG. 7B).

  Thus, the mirror actuator 1 is fixed to the holding frame 310, and the structure shown in FIG. 13 is assembled. FIG. 13 is a perspective view showing the laser radar 300 with the cover 301b of the casing 301 removed. Finally, the cover 301b (see FIG. 8) is attached to the base 301a, and the assembly of the laser radar 300 is completed.

In this state, the mirror actuator 1 tilts at a predetermined angle (for example, 15 degrees) so that the mirror surface of the mirror 123 approaches the positive Z-axis direction from the positive Y-axis direction to the in-plane direction of the YZ plane. Be placed. Further, as described above, the light receiving unit 500 and the laser unit 400 are arranged so as to be inclined at a predetermined angle (for example, 30 degrees) so as to approach the Z-axis positive direction in the in-plane direction of the YZ plane from the Y-axis positive direction. Has been. Therefore, in the mirror actuator 1, when the mirror 123 is in the neutral position, the incident angle of the laser light emitted from the mirror surface of the mirror 123 and the laser light source 401 becomes a predetermined angle (for example, 45 degrees). The “neutral position” refers to a position where the mirror 123 is not rotated by the mirror actuator 1 and is perpendicular to the front-rear direction of FIG. At the neutral position, the laser light from the beam shaping lens 402 is incident on the approximate center of the mirror 123.

  By arranging the laser light source 401 and the mirror actuator 1 in this way, the laser light emitted from the laser light source 401 when the mirror 123 is in the neutral position is reflected by the mirror 123 and proceeds in the positive direction of the Z axis. Become. At this time, an inclined portion 511a is provided at the upper portion (Y-axis positive direction) of the lens barrel 511, and the upper portion (Y-axis positive direction) of the light transmission plate 413 is cut by the cut portion 413a. The emitted laser light is not shielded by these members. Similarly, the reflected light from the target area is not blocked, and the reflected light is appropriately guided to the mirror 123 of the mirror actuator 1.

  Returning to FIG. 8, as described above, the mirror actuator 1 rotates the mirror 123 around two axes around the mirror 123 on which the outgoing laser light transmitted through the beam shaping lens 402 and the reflected light from the target region are incident. And a mechanism for moving. As the mirror 123 rotates, the emitted laser beam is scanned in the target area. The laser light is scanned along a plurality of scanning lines parallel to the XZ plane in the target area. In order to scan the laser beam along each scanning line, the mirror 123 is driven not only in the Pan direction but also in the Tilt direction. Further, in order to change the scanning line, the mirror 123 is driven in the tilt direction.

  The reflected light from the target area travels back along the optical path of the emitted laser beam toward the target area and enters the mirror 123. The reflected light incident on the mirror 123 is reflected by the mirror 123 and is not shielded in the region above the cut portion 413a (see FIG. 11C), passes through the opening 511b, and passes through the bandpass filter 501. Then, the light is incident on the lens surface of the light receiving lens 502. In addition, below the cut portion 413a (see FIG. 11C), the reflected light from the target region passes through the light transmission plate 413 and passes through the band-pass filter 501 on the lens surface of the light receiving lens 502. Incident at the bottom. Thus, the reflected light incident on the upper and lower portions of the light receiving lens 502 is converged on the photodetector 503 by the light receiving lens 502.

  The behavior of the reflected light is the same regardless of the rotation position of the mirror 123. That is, regardless of the rotation position of the mirror 123, the reflected light from the target region travels in the optical path of the emitted laser light and travels parallel to the optical axis of the beam shaping lens 402, and reaches the light receiving lens 502. Incident.

  The circuit board 600 measures the presence / absence of an object in the target region and the distance to the object based on the signal from the photodetector 503. Specifically, the distance to this object is measured from the time difference between the timing at which the laser beam is emitted and the timing at which the signal is output from the photodetector 503. The circuit configuration of the laser radar 300 will be described later with reference to FIG.

  FIG. 14A and FIG. 14B are diagrams illustrating a servo optical system for detecting the position of the mirror 123. FIG. 14A shows only a partial sectional view of the mirror actuator 1 and the laser light source 401.

  Referring to FIG. 14A, as described above, the mirror actuator 1 is provided with the LED 122, the pinhole box 244, the PSD substrate 241, and the PSD 242.

The LED 122, PSD 242 and pin hole 244a are arranged so that the LED 122 faces the pin hole 244a of the pin hole box 244 and the center of the PSD 242 when the mirror 123 of the mirror actuator 1 is in the neutral position. That is, the pinhole box 244 and the PSD 242 are arranged so that the servo light emitted from the LED 122 and passing through the pinhole 244a is perpendicularly incident on the center of the PSD 242 when the mirror 123 is in the neutral position. Further, the pinhole box 244 is disposed at a position closer to the PSD 242 than an intermediate position between the LED 122 and the PSD 242.

  Here, a part of the servo light emitted so as to diffuse from the LED 122 passes through the pinhole 244 a and is received by the PSD 242. The servo light incident on the area other than the pinhole 244a is shielded by the pinhole box 244. The PSD 242 outputs a current signal corresponding to the light receiving position of the servo light.

  For example, as shown in FIG. 14B, when the mirror 123 rotates from the neutral position indicated by the broken line in the direction of the arrow, the optical path of the light passing through the pinhole 244a out of the diffused light (servo light) of the LED 122 is from LP1 to LP2. And displace. As a result, the irradiation position of the servo light on the PSD 242 changes, and the position detection signal output from the PSD 242 changes. In this case, the light emission position of the servo light from the LED 122 and the incident position of the servo light on the light receiving surface of the PSD 242 have a one-to-one correspondence. Therefore, the position of the mirror 123 can be detected based on the incident position of the servo light detected by the PSD 242, and as a result, the scanning position of the scanning laser light in the target area can be detected.

  FIG. 15 is a diagram illustrating a circuit configuration of the laser radar 300. For the sake of convenience, the main configuration of the laser radar 300 is also shown in FIG. As illustrated, the laser radar 300 includes a PSD signal processing circuit 601, a servo LED driving circuit 602, an actuator driving circuit 603, a scan LD driving circuit 604, a PD signal processing circuit 605, and a DSP 606.

  The PSD signal processing circuit 601 outputs a position detection signal obtained based on the output signal from the PSD 242 to the DSP 606. The servo LED drive circuit 602 supplies a drive signal to the LED 122 based on the signal from the DSP 606. The actuator drive circuit 603 drives the mirror actuator 1 based on the signal from the DSP 606. Specifically, a drive signal for scanning the laser beam along a predetermined trajectory in the target area is supplied to the mirror actuator 1.

  The scan LD drive circuit 604 supplies a drive signal to the laser light source 401 based on the signal from the DSP 606. Specifically, a pulsed drive signal (current signal) is supplied to the laser light source 401 at the timing of irradiating the target region with laser light.

  The PD signal processing circuit 605 amplifies and digitizes a voltage signal corresponding to the amount of light received by the photodetector 503 and supplies the amplified signal to the DSP 606.

  The DSP 606 detects the scanning position of the laser beam in the target area based on the position detection signal input from the PSD signal processing circuit 601, and executes drive control of the mirror actuator 1, drive control of the laser light source 401, and the like. . Further, the DSP 606 determines whether an object is present at the laser light irradiation position in the target area based on the voltage signal input from the PD signal processing circuit 605, and at the same time, the laser light output from the laser light source 401. The distance to the object is measured based on the time difference between the irradiation timing and the reception timing of the reflected light from the target area received by the photodetector 503.

  FIG. 16 is a diagram showing laser beam scanning control in the target area.

  In the present embodiment, three horizontal scanning lines L1 to L3 are set as the target area. The DSP 606 controls the mirror actuator 1 so that the laser light scans these scanning lines L1 to L3 from left to right. The laser beam scans the scanning lines L1 to L3 at a constant speed. Further, the laser beam scans each scanning line L1 to L3 from a position ahead of the start position Ps of each scanning line L1 to L3 to a position behind the end position Pe. Such control is performed by the DSP 606 controlling the mirror actuator 1 so that the servo light follows the target trajectory set on the PSD 242. That is, when the laser beam scans the target area along the three scanning lines L1 to L3 shown in FIG. 16, the servo light also scans on the PSD 242 along the three trajectories. The DSP 606 holds the trajectory as a target trajectory by a table or the like, and controls the mirror actuator 1 so that the servo light follows the target trajectory.

  Scanning of the laser beam in the target region starts from the uppermost scanning line L1, then moves to the scanning line L2, and finally to the scanning line L3. When scanning from the scanning line L1 to the scanning line L3 is completed, the scanning returns to the scanning line L1 and the next scanning for the target area is performed.

  The DSP 606 causes the laser light source 401 to emit light in pulses at the timing when the scanning position reaches the start position Ps of each scanning line L1 to L3. After that, the laser light source 401 is caused to emit light in a pulsed manner at regular time intervals Δt until the scanning position reaches the end position Pe. Note that black circles in FIG. 16 schematically indicate the irradiation timing of the laser light.

  In the present embodiment, the laser light is emitted at a constant time interval Δt while being scanned at a constant speed, so that the displacement Δp of the irradiation position of the laser light in the target region is also constant. In addition, the angle of the mirror 123 controlled by the mirror actuator 1 at regular time intervals Δt is also constant.

  FIG. 17 is a diagram illustrating the relationship between the distance to the object and the focal length. FIG. 17 shows a laser radar 300, laser beams P1 to Pn that scan a predetermined scanning line at predetermined light emission timings T1 to Tn, and persons H1 to H3 standing at different distances as detection objects. . Further, the focal length of the beam shaping lens 402 is indicated by a broken line.

  Referring to FIG. 17, as described above, in the present embodiment, focus adjustment of beam shaping lens 402 is performed so that the focal length is approximately 15 m. The person H1 stands at a position closer to the direction of the laser radar 300 than the focal length of 15 m. The person H2 stands at a position (for example, approximately 10 m) that is considerably closer to the direction of the laser radar 300 than the focal length of 15 m. The person H3 stands at a position (for example, approximately 20 m) that is far from the laser radar 300 than the focal length of 15 m.

  When the laser beam is scanned along a predetermined scanning line in this state, the person H2 is irradiated with the laser beams P2 to P4, the person H1 is irradiated with the laser beams P6 and P7, and the person H3 is irradiated with the laser beam P10. Is irradiated.

  FIGS. 18A, 18C, and 18D are diagrams schematically showing the beam shape and size of laser light at the positions of the persons H1, H2, and H3. FIG. 18B schematically shows a beam shape at the same position in FIG. 18A when an elliptical beam extending in the horizontal direction is irradiated as a comparative example. .

FIG. 18A shows the beam shapes of the laser beams P5 to P8 irradiated at a predetermined continuous light emission timing at the position of the person H1. Since the person H1 is located at substantially the same distance as the focal length of 15 m, the beams of the laser beams P5 to P8 are properly converged into an elliptical shape extending in the vertical direction. The beams of the laser beams P5 to P8 adjacent to each other are irradiated on the target area so as not to overlap each other and to form a very small gap S1. In this case, since the laser beams P5 and P8 are not reflected by the object, it is detected that no object exists in this region. The laser beams P6 and P7 are reflected by the person H1, and distance information on the position of the person H1 is obtained in this region from the difference between the laser beam emission timing and the reflected light reception timing.

  As described above, the laser radar 300 can appropriately obtain distance information with respect to an object having a focal length of about 15 m. Here, in the horizontal direction, the resolution per unit area of the obtained distance information (the number of distance information) depends on the laser light irradiation interval Δp1 corresponding to the constant time interval Δt.

  When the beam diameter is larger than necessary than the laser light irradiation interval Δp1, the obtained distance information has low accuracy with respect to the obtained resolution. For example, as shown in the comparative example of FIG. 18B, when the laser beams P5 ′ to P8 ′ are irradiated so as to have an elliptical shape extending in the horizontal direction, the reflected light from the person H1 at all emission timings. Is received, and distance information of the position of the person H1 is obtained at all positions. As described above, in the comparative example, the accuracy of the obtained distance information is low although the resolution is equivalent to that in FIG.

  Therefore, for example, when the laser radar 300 is used as a security application in which a person is a main detection target, the scanning direction of the laser radar is set to the horizontal direction, and the beam shape is shaped so that the beam diameter in the horizontal direction is reduced. It is desirable to be done.

  However, if the beam diameter is smaller than necessary than the laser beam irradiation interval Δp1, the gap between the adjacent laser beams becomes large, making it difficult to detect a small object. Therefore, in order to obtain accurate distance information with respect to the resolution per unit area and detect a small object without omission, the gap between adjacent beams is very small or adjacent to each other. It is desirable to set the matching beams so that they overlap slightly. In the present embodiment, in order to obtain more accurate distance information with respect to the resolution per unit area, the gap S1 between the beam shapes of adjacent laser beams is set to be very small at the focal length. Is done.

  FIG. 18C shows the beam shapes of the laser beams P1 to P5 irradiated at a predetermined continuous light emission timing at the position of the person H2. The person H2 is located at a position (for example, 10 m) that is considerably closer to the laser radar 300 than the focal length of 15 m.

  Since the laser beams P1 to P5 at these positions are out of focus, the beam shape is slightly unclear due to aberration. However, in the case of FIG. 18C, the reflected light amount incident on the laser radar 300 is large because it is closer to the laser radar 300 than in the case of FIG. The effect of aberrations on is negligible.

  Further, the beam diameters of the laser beams P1 to P5 at this position are considerably smaller than the beam diameter at a position close to the focal length shown in FIG. Further, the laser light irradiation interval Δp2 corresponding to the constant time interval Δt is also narrower than the irradiation interval Δp1 at a position close to the focal length shown in FIG.

In this case, the laser beams P1 and P5 are not reflected by the object, and it is detected that no object exists in this region. Further, the laser beams P2 to P4 are reflected by the person H2, and distance information of the position of the person H2 is obtained in this region from the difference between the emission timing of the laser beam and the light reception timing of the reflected light.

  In this way, in the case of FIG. 18C, the person H2 is irradiated with the laser beams P2 to P4 at three emission timings, and this distance information is obtained. That is, the resolution of the distance information for the same unit area in FIG. 18A in the horizontal direction is higher than that in the case of FIG. In the case of FIG. 18C, since the width of the irradiation range of the laser beams P1 to Pn is narrowed, the resolution of the distance information obtained by the entire laser beams P1 to Pn is not different from the case of FIG. . As described above, the range in which the distance information can be acquired is narrower than that in FIG.

  As described above, the laser radar 300 can appropriately acquire distance information for an object that is closer than the focal distance, although the range in which the distance information can be acquired is narrow.

  FIG. 18D shows the beam shapes of the laser beams P9 to P11 irradiated at a predetermined continuous light emission timing at the position of the person H3. As described above, the person H3 is located at a position (for example, 20 m) far from the laser radar 300 than the focal length of 15 m.

  The laser beams P9 to P11 at this position are out of focus and the beam shape is considerably unclear due to aberration. Further, in the case of FIG. 18D, since the distance is far from the laser radar 300, the amount of reflected light incident on the laser radar 300 is considerably reduced.

  Further, the beam diameter of the laser beams P9 to P11 at this position is considerably larger than the beam diameter at a position close to the focal length shown in FIG. Further, the laser light irradiation interval Δp3 corresponding to the constant time interval Δt is also considerably wider than the irradiation interval Δp1 at a position close to the focal length shown in FIG.

  In this case, the laser beams P9 and P11 are not reflected by the object, and it is detected that no object exists in this region. The laser beam P10 is reflected by the person H3, but the amount of reflected light incident on the laser radar 300 is small, the intensity of the signal output from the photodetector 503 does not exceed the threshold value, and the distance information is appropriately set. There is a possibility that it cannot be acquired.

  In this way, in the case of FIG. 18D, the person H3 is irradiated with the laser beam P10 at one emission timing. That is, the resolution for the same unit area in the horizontal direction as in FIG. 18A is lower than that in the case of FIG.

  As described above, there is a possibility that the laser radar 300 cannot properly acquire distance information for an object that is far away from the focal length, and further, the resolution of the distance information per unit area in the horizontal direction is deteriorated. Will be.

  Therefore, for example, when the laser radar 300 used in a narrow room is used in a large room and the environment in which the laser radar 300 is used changes and the distance of the object to be detected becomes a long distance, the distance information acquisition accuracy is improved. It will have an adverse effect.

  In this case, distance information can be appropriately acquired by performing focus adjustment using the focus adjustment mechanism of the laser unit 400 of the laser radar 300.

  FIG. 19 is a diagram for explaining the focus adjustment of the laser unit 400.

  Referring to FIG. 19A, at the time of focus adjustment, first, the holding screw 411d is loosened. Thereby, the lens holder 414 can be rotated along the screw groove 411h. By rotating the lens holder 414, the beam shaping lens 402 moves in the front-rear direction, and the distance L1 from the laser light source 401 can be adjusted. In this state, focus adjustment is performed so that the laser beam is focused in a target region at a desired distance. For example, when adjusting the beam shaping lens 402 that has been adjusted to focus at a position of approximately 15 m so as to focus at a position of approximately 20 m, first, the screen is placed at a target distance (approximately 20 m). The screen is irradiated with laser light. In this state, the signal intensity from the photodetector 503 is monitored while the beam shaping lens 402 is moved in the front-rear direction. Then, the beam shaping lens 402 is positioned at a position where the monitored signal intensity is maximized. Thereby, the position of the beam shaping lens 402 is adjusted so as to approach the laser light source 401, and the distance between the laser light source 401 and the beam shaping lens 402 is adjusted to L2.

  Thus, when the position of the beam shaping lens 402 in the front-rear direction is adjusted, the holding screw 411d is screwed into the screw hole 411c again. Accordingly, the tip of the holding screw 411d is pressed against the upper surface of the small diameter portion 414b of the lens holder 414, and the lower surface of the small diameter portion 414b is pressed against the large diameter portion 411a of the laser holder 411. Thereby, the lens holder 414 is fixed to the laser holder 411.

  As described above, the focus adjustment of the beam shaping lens 402 can be performed by an easy operation such as loosening the holding screw 411d and rotating the lens holder 414.

  Thereafter, the position of the beam shaping lens 402 in the rotation direction is adjusted so that the beam shape becomes a predetermined shape (vertically long) in the target region. That is, once the fastening screw 412 is loosened, the lens holder 414 can be rotated. In this state, the laser holder 411 is rotated to a position where the beam shape becomes a predetermined shape (longitudinal shape) in the target region, and then the retaining screw 412 is tightened. Thereby, the position adjustment of the beam shaping lens 402 in the rotation direction is completed, and the laser beam is irradiated to the target region with no aberration and in a vertically long shape.

  As described above, according to this embodiment, focus adjustment can be easily performed, and laser light can be emitted so as to focus on an appropriate distance according to the use environment. Therefore, even if the distance to the object changes greatly according to the usage environment, the distance information of the object can be acquired appropriately.

  Further, according to the present embodiment, the lens holder 414 can be moved in the front-rear direction in a screw shape along the screw groove 411h of the laser holder 411, so that the beam shaping lens 402 can be stably and easily moved. Focus adjustment can be performed.

  Further, according to the present embodiment, since the holding screw 411d is provided, the fixing operation of the lens holder 414 can be easily performed.

  Although the embodiments of the present invention have been described above, the present invention is not limited to the above embodiments, and various modifications can be made to the embodiments of the present invention other than the above.

For example, in the above embodiment, the screw groove 411h of the laser holder 411 and the screw groove 414c of the lens holder 414 are formed, and the lens holder 414 is moved in the front-rear direction (focus direction) along the screw groove. A configuration in which the small-diameter portion 414b of the lens holder 414 is simply fitted into the opening 411f of the laser holder 411 without forming a screw groove may be employed. In this configuration, the screw grooves 411h and 414c that mesh with each other are omitted. Therefore, even if the lens holder 414 is not rotated as in the above embodiment, the small diameter portion 414b is guided to the opening 411f, and the lens holder 414 is moved back and forth. It can be moved linearly in the direction. In this case, in order to restrict the rotation of the lens holder 414, for example, a protrusion extending in the front-rear direction is formed on the outer surface of the small diameter portion 414b, and before and after engaging with the protrusion on the inner surface of the opening 411f. An extending groove may be formed. In this case, since the beam shaping lens 402 does not rotate during focus adjustment, the rotational position of the beam shaping lens 402 is adjusted after focus adjustment by mounting the beam shaping lens 402 in advance so that the beam shape is vertically long in the target area. There is no need to do.

  In the above embodiment, the lens holder 414 is pressed against the laser holder 411 and fixed by the holding screw 411d. However, the lens holder 414 is pressed against the laser holder 411 using the biasing force of the spring member. The lens holder 414 may be pressed against the laser holder 411 and fixed using a magnetic force of a magnet.

  Further, in the above embodiment, the laser unit 400 is attached integrally with the light receiving unit 500, but may not be attached integrally, and may be disposed alone in the housing 301 of the laser radar 300.

  In the above embodiment, the configuration example of the laser radar of the type in which the optical path of the emitted light and the optical path of the reflected light coincide with each other is shown. However, the laser unit 400 and the light receiving unit 500 are separately arranged, and the optical path is not located. The present invention may be used for a type of laser radar.

  In the above-described embodiment, a configuration in which one beam shaping lens 402 is provided is shown. However, in the case where focusing is performed at a longer distance than in this embodiment, a plurality of beam shaping lenses 402 are provided. It may be configured as follows.

  In the above-described embodiment, the mirror actuator 1 is used as a configuration for scanning the laser beam in the target area. For example, other than a lens actuator or a polygon mirror that drives the lens in a direction perpendicular to the optical axis. You may scan a laser beam using the structure of.

  Furthermore, in the said embodiment, although the upper part of the light transmissive plate 413 was cut, the shape of the light transmissive plate 413 is not restricted to this. For example, a circular light transmission plate may be used without cutting the upper portion. Further, the member for supporting the laser unit 400 is not limited to the light transmitting plate 413, and a member having no light transmitting property may be used. However, when using such a member, it is necessary to devise the shape of the member so as not to block light from the target region as much as possible.

  In addition, the embodiment of the present invention can be variously modified as appropriate within the scope of the technical idea shown in the claims.

1 ... Mirror actuator (scanning part)
300 ... Laser radar 400 ... Laser unit (focus adjustment unit)
401 ... Laser light source 402 ... Beam shaping lens 411 ... Laser holder (focus adjustment unit)
411d ... Holding screw (fixture, screw)
411f ... Opening (guide part)
411h ... Screw groove (guide portion, first screw portion)
414 ... Lens holder (focus adjustment unit)
414c ... Screw groove (guide portion, second screw portion)
502. Light receiving lens (light collecting element)
503 ... Photodetector

Claims (6)

A laser light source for emitting laser light;
A beam shaping lens for shaping the beam shape of the laser light;
A scanning unit that scans the laser light transmitted through the beam shaping lens in a target area;
A condensing element for condensing the reflected light reflected in the target area;
A photodetector for receiving the reflected light collected by the light collecting element;
A focus adjustment unit for adjusting a distance between the laser light source and the beam shaping lens;
A laser radar characterized by that. The laser radar according to claim 1, wherein
The focus adjustment unit
A lens holder for accommodating the beam shaping lens;
A laser holder that houses the laser light source and the lens holder;
A guide unit for guiding the lens holder in the direction in which the laser light source and the beam shaping lens are arranged;
A laser radar characterized by that. The laser radar according to claim 2, wherein
The guide portion includes a first screw portion formed on the laser holder and a second screw portion formed on the lens holder that meshes with the first screw portion.
A laser radar characterized by that. The laser radar according to claim 2 or 3,
A fixture for pressing and fixing the lens holder against the laser holder;
A laser radar characterized by that. The laser radar according to claim 4, wherein
The fixture includes a screw that penetrates the laser holder and presses and fixes the lens holder to the laser holder.
A laser radar characterized by that. The laser radar according to any one of claims 1 to 5,
The laser light source, the beam shaping lens, the condensing element, and the photodetector are arranged in a line in the traveling direction of the reflected light.
A laser radar characterized by that.

Images