JP2016080899A - Optical scanner - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an optical scanner capable of making distortion in the scan range of light small even if the scan range is widened and achieving compactness and thinness of the scanner.SOLUTION: An optical scanner 10 includes: a movable frame rotating about a first axis a1; a movable section that is supported by the movable frame under a rotatable state about a second axis a2 to rotate; a mirror 14 disposed in the movable section; and an optical output section 11 for generating output light. The optical scanner is configured such that the mirror 14 includes a reflection surface slanted with respect to the second axis a2, an optical axis a0 along which output light enters into the reflection surface is oriented to a direction having a large direction component of the second axis a2, and the direction of radiation of the output light having reflected by the reflection surface changes into two directions by the rotation of the movable frame and that of the movable section.SELECTED DRAWING: Figure 1

Description

  The present invention relates to an optical scanning apparatus that moves an irradiation destination of light in two directions.

  For example, in a laser radar or a scanning projector, an optical scanning device that moves a light irradiation destination in two directions is used. In a general optical scanning device, a configuration is used in which laser light is reflected by a mirror and irradiated to the outside, and the irradiation destination of the light is moved by changing the angle of the mirror (see, for example, Patent Document 1). Hereinafter, the movement of the light irradiation destination is called scanning, and the movement range of the light irradiation destination is called a scanning range.

  In the optical scanning device, when the rotation angle of the mirror is increased to widen the light scanning range, there is a problem that the light scanning range is distorted. That is, when the mirror is rotated in the horizontal direction within an angle range of −90 ° to + 90 ° and the light is scanned in the horizontal direction, the mirror is in the vicinity of 0 ° and the mirror is in the vicinity of −90 ° or + 90 °. There is a case where the light irradiation destination is shifted in the vertical direction when it is in the vicinity, and scanning with the same height cannot be performed.

  To deal with such a problem, Patent Document 2 discloses a technique for reducing distortion in the scanning range of light by appropriately setting the angle of the reflecting surface and the angle of the rotation axis.

JP 2012-154806 A JP 2011-197575 A

  In recent years, there has been a demand for a compact, particularly thin, optical scanning device. For example, in-vehicle laser radar is required to be disposed in a small space in the front part or rear part of the vehicle, so that the apparatus needs to be thinned in the front-rear direction.

  However, in the above-described conventional configuration in which the light scanning range is widened and the distortion of the light scanning range is reduced, there is a problem that the thickness in the front-rear direction of the apparatus increases in order to ensure the arrangement of the light output unit. Further, in the above-described conventional configuration in which the light scanning range is widened and the distortion of the light scanning range is reduced, there is a problem that the mechanism for rotating the mirror is complicated and large, and the entire apparatus is large.

  SUMMARY OF THE INVENTION An object of the present invention is to provide an optical scanning device that can reduce the distortion of the light scanning range even if the light scanning range is widened, and that can reduce the size and thickness of the device.

  An optical scanning device according to an aspect of the present invention is supported so as to be rotatable about a first axis, the movable frame that rotates about the first axis, and the movable in a state of being rotatable about a second axis. A movable part supported by a frame and rotating at a larger rotation angle than the movable frame, a mirror disposed on the movable part, and a light output part for generating output light, the mirror comprising the first The optical axis of the output light that has a reflecting surface inclined with respect to two axes, and is incident on the reflecting surface is a directional component of the first axis, and both the first axis and the second axis. The direction in which the direction component of the second axis is larger than the vertical direction component, and the irradiation direction of the output light reflected by the reflecting surface is divided into two directions by rotation of the movable frame and rotation of the movable portion. Adopt a configuration that changes.

  According to the present invention, even when the light scanning range is widened in the rotation direction about the second axis, distortion of the light scanning range can be reduced, and the apparatus can be made compact and thin.

1 is a configuration diagram illustrating an optical scanning device according to a first embodiment of the present invention. Perspective view showing mirror and actuator Side view showing the inside of the actuator The figure which shows the locus | trajectory of the emitted beam of the optical scanning device of Embodiment 1. Configuration diagram showing an optical scanning device according to a second embodiment of the present invention. The figure which shows the locus | trajectory of the emitted beam of the optical scanning device of Embodiment 2. Configuration diagram showing optical scanning device of comparative example The figure which shows the locus | trajectory of the emitted beam of the optical scanning apparatus of a comparative example

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

(Embodiment 1)
FIG. 1 is a configuration diagram illustrating an optical scanning device according to a first embodiment of the present invention.

  The optical scanning device 10 according to the first embodiment is a laser radar device that outputs laser light to the outside, performs scanning, detects reflected light that has returned, and detects surrounding objects (for example, obstacles). . The optical scanning device 10 includes a light output unit 11, a collimator lens 12, a beam splitter 13, a mirror 14, an optical filter 15, a condenser lens 16, an optical sensor 17, a monitoring optical sensor 18, and an actuator. 20.

  Note that the components necessary for the optical scanning device 10 are a light output unit 11, a collimating lens 12, a mirror 14, and an actuator 20. If the optical scanning device 10 only needs to scan light, the other configuration may be omitted, or another configuration may be provided as a separate device.

  The light output unit 11 is a laser diode, for example, and generates laser light as output light.

  The collimating lens 12 makes the output light of the light output unit 11 parallel light.

  The beam splitter 13 separates output light and return light. The return light refers to the light returned from the output light reflected by the object whose distance or the like is to be measured. The beam splitter 13 transmits the output light of the light output unit 11 and sends it to the mirror 14, while reflecting the return light returning from the outside via the mirror 14 and sending it to the optical sensor 17. Specifically, the beam splitter 13 may have a configuration in which a transmission portion (for example, a transmission window) is provided in a portion where the light beam of the light output portion 11 passes and the other range is a mirror.

  The mirror 14 reflects the output light of the light output unit 11 and irradiates it outside the apparatus. The mirror 14 is rotated in two rotation directions around two axes by the actuator 20 to change the direction in which the output light is irradiated in two directions. The inclination angle of the mirror 14 and the direction of the optical axis of the light output unit 11 will be described later.

  The optical filter 15 transmits the output light (for example, infrared light) of the light output unit 11 and absorbs light of other wavelengths (for example, visible light wavelength).

  The condensing lens 16 condenses the return light separated by the beam splitter 13.

  The optical sensor 17 is, for example, a photodiode, and detects the intensity of the light collected by the condenser lens 16.

  The monitoring optical sensor 18 monitors the intensity of the output light from the light output unit 11 in order to adjust the output intensity of the light output unit 11. The monitoring optical sensor 18 is, for example, a photodiode, and is provided at a position where light leaked from the light output unit 11 strikes.

  FIG. 2 is a perspective view showing a mirror and an actuator. FIG. 3 is a side view showing the inside of the actuator.

  The actuator 20 is a device that drives the mirror 14 in two rotational directions using electromagnetic force. The actuator 20 includes a movable portion 23, a movable frame 21, a pair of linear springs 22, 22, 24, 24, a pair of magnets 27a, 27a, a single magnet 27b, and electromagnets 28, 29. And.

  The movable frame 21 is supported by the machine frame of the actuator 20 by a linear spring 22, and rotates about the first axis a1 when the linear spring 22 is twisted. The angle range in which the movable frame 21 rotates is relatively small, specifically narrower than −30 ° to + 30 °, more specifically narrower than −20 ° to + 20 °, and −15 ° to The angle range is set wider than + 15 °.

  The movable portion 23 is connected to the movable frame 21 by a linear spring 24, and rotates about the second axis a2 along the linear spring 24 when the linear spring 24 is twisted. The angle range in which the movable portion 23 rotates is set to be larger than the rotation angle range of the movable frame 21, specifically, an angle range wider than −70 ° to + 70 ° and narrower than −90 ° to + 90 °. ing.

  The movable part 23 is provided with a mirror 14. The movable part 23 and the mirror 14 may be formed integrally, or a separate structure may be bonded or mechanically connected.

  The magnet 27 a is a permanent magnet for generating a driving force, and is fixed to the movable frame 21. The magnet 27a protrudes and is fixed behind the rotation axis (first axis a1) of the movable frame 21 (left side in FIG. 3).

  The magnet 27 b is a permanent magnet for generating a driving force, and is fixed to the movable portion 23. The magnet 27b is fixed at a position away from the rotation axis (second axis a2) of the movable portion 23.

  The electromagnet 28 has a yoke and an electromagnetic coil, and applies an electromagnetic force to the magnet 27a. The electromagnet 28 rotates the movable frame 21 within a predetermined angle range around the rotation axis (first axis a1). The electromagnet 28 can rotate the movable frame 21 so that the clockwise rotation and the counterclockwise rotation are alternately repeated at a substantially constant cycle.

  The electromagnet 29 has a yoke and an electromagnetic coil, and applies an electromagnetic force to the magnet 27b. The electromagnet 29 rotates the movable portion 23 within a predetermined angle range around the rotation axis (second axis a2). The electromagnet 29 can rotate the movable portion 23 so as to alternately repeat the right-handed rotation and the left-handed rotation at a substantially constant cycle.

<Inclination angle of mirrors, etc.>
Next, the relationship among the inclination angle of the reflecting surface of the mirror 14, the driving direction of the actuator 20, and the optical axis direction of the output light will be described. Hereinafter, when the movable frame 21 is at the center position of the rotation range of the movable frame 21, that is, when the movable frame 21 is rotated within a range of −20 ° to + 20 °, the actuator 20 is Called the reference state.

  The reflecting surface of the mirror 14 is set to be inclined by 45 ° with respect to the second axis a2 when the actuator 20 is in the reference state. Furthermore, the reflecting surface of the mirror 14 is set to be parallel to the first axis a1.

  The inclination of the reflecting surface of the mirror 14 with respect to the second axis a2 and the direction with respect to the first axis a1 may include ± 15 ° as an error. Even if this level of error is included, the operational effects of the present embodiment are similarly obtained.

  In the reference state, the actuator 20 has the first axis a1 arranged substantially horizontally and the second axis a2 arranged substantially vertically. “Substantially horizontal” includes a range of ± 15 ° from a completely horizontal orientation. Further, “substantially vertical” includes a range of ± 15 ° from a completely vertical direction.

  The optical axis a0 of the output light incident on the reflecting surface of the mirror 14 is set to be parallel to the second axis a2.

  The angle of the optical axis a0 may include ± 5 ° as an error. Even if this level of error is included, the operational effects of the present embodiment are similarly obtained.

  With the above configuration, in the optical scanning device 10, the actuator 20 can be thinned in the front-rear direction (left-right direction in FIG. 1). Further, according to the optical scanning device 10, the light output unit 11 is arranged in the direction of the second axis a <b> 2 (e.g., upward in FIG. 1) from the actuator 20, so that the light output unit 11 is positioned in front of the actuator 20 ( There is no need to greatly separate (to the right in FIG. 1). Therefore, the optical scanning device 10 according to the first embodiment can have a compact configuration that is thin in the front-rear direction (left-right direction in FIG. 1).

<Scanning range>
FIG. 4 is a diagram illustrating the locus of the outgoing beam of the optical scanning device according to the first embodiment.

  The optical scanning device 10 tilts the mirror 14 about −17 ° to + 17 ° about the first axis a1 and rotates the mirror 14 about −2 ° to 80 ° about the second axis a2. A scanning range of the output light as shown by the solid line in FIG. 4 is obtained. A broken line in FIG. 4 indicates a rotation range of the movable frame 21 and the movable portion 23. As shown in FIG. 4, when the horizontal rotation angle is large, the scanning range of the optical scanning device 10 is slightly reduced in the vertical direction in the scanning range, but becomes a scanning range with less distortion as a whole. .

<Comparative example>
FIG. 7 is a configuration diagram illustrating an optical scanning device of a comparative example. FIG. 8 is a diagram illustrating the locus of the outgoing beam of the optical scanning device of the comparative example.

  The optical scanning device 110 of the comparative example is an example in which the mirror 114 is disposed without tilting the reflection surface with respect to the second axis a2 of the actuator 120.

  In the optical scanning device 110 of the comparative example, the light output unit 111, the collimating lens 112, the beam splitter 113, the mirror 114, the optical filter 115, the condensing lens 116, the optical sensor 117, and the monitoring optical sensor 118. The actuator 120 is the same as the corresponding configuration in the first embodiment, and only the arrangement and orientation are different. In the optical scanning device 110 of the comparative example, in order to reduce the depth of the device, a mirror 119 is added to increase the return of the output light of the light output unit 111 by one stage.

  In the optical scanning device 110 of the comparative example, the mirror 114 is tilted from −17 ° to + 17 ° around the first axis a1 and the mirror 114 is moved from −80 ° to 80 around the second axis a2 by driving the actuator 120. When rotated to 0 °, a scanning range of output light as shown by the solid line in FIG. 8 is obtained. This scanning range is a scanning range in which the scanning position of light is greatly distorted when the rotation angle about the second axis a2 is large. A broken line in FIG. 8 indicates a rotation range of the movable frame 21 and the movable portion 23. In the scanning range of the comparative example, when the horizontal rotation angle is large, the actual light scanning range (solid line in FIG. 8) is lower than the mirror rotation range (dashed line in FIG. 8).

  Further, in the optical scanning device 110 of the comparative example, in order to irradiate the output light in the horizontal direction, the rotation axis (second axis a2) of the actuator 120 is inclined and the light output unit 111 is also in front of the actuator 120 ( They must be placed apart (to the right in FIG. 7). Therefore, the optical scanning device 110 is increased in size, and in particular, it cannot be thinned in the front-rear direction (left-right direction in FIG. 7).

  As described above, according to the optical scanning device 10 of the first embodiment, as can be seen from the comparison with the comparative example, even if the scanning range of the output light is increased in the horizontal rotation direction, the distortion of the scanning range of the light is Can be reduced. Furthermore, as described above, the optical scanning device 10 can be made compact and the optical scanning device 10 can be made thin.

(Embodiment 2)
FIG. 5 is a block diagram showing an optical scanning device according to the second embodiment of the present invention.

  The optical scanning device 10A of the second embodiment is an example in which the actuator 20 is arranged in a different direction from that of the first embodiment, and the other configurations are the same as those of the first embodiment. In the first embodiment, the same components are denoted by the same reference numerals, and the description thereof is omitted.

  In the actuator 20, the orientation of the second axis a2 in the standard state is inclined + 10 ° with respect to the optical axis a0 of the output light incident on the reflecting surface of the mirror 14. In the tilt direction, the direction in which the reflecting surface of the mirror 14 approaches perpendicular to the optical axis a0 of the output light is defined as a positive direction.

  The inclination angle of the second axis a2 with respect to the optical axis a0 may include ± 5 ° as an error. Even if this level of error is included, the operational effects of the present embodiment are similarly obtained.

  FIG. 6 is a diagram illustrating a locus of an outgoing beam of the optical scanning device according to the second embodiment.

  In the optical scanning device 10A according to the second embodiment, the mirror 14 is tilted from −17 ° to + 17 ° around the first axis a1, and the mirror 14 is rotated from −80 ° to 80 ° around the second axis a2. In this case, a scanning range of the output light as shown by the solid line in FIG. 6 is obtained. A broken line in FIG. 6 indicates a rotation range of the movable frame 21 and the movable portion 23. In the scanning range of the second embodiment, when the rotation angle in the horizontal direction is large, the scanning range is distorted in the vertical direction. However, in the second embodiment, even when the horizontal rotation angle is large, the actual light scanning range (solid line in FIG. 6) does not deviate from the rotation range of the mirror 14 (broken line in FIG. 6).

  As described above, according to the optical scanning device 10A of the second embodiment, the actuator 20 can be thinned in the front-rear direction (the left-right direction in FIG. 5), as in the first embodiment. Further, according to the optical scanning device 10 </ b> A, the light output unit 11 is arranged away from the actuator 20 in the direction of the second axis a <b> 2, so that it is not necessary to largely separate the light output unit 11 in front of the actuator 20. Therefore, the optical scanning device 10A can have a compact configuration that is thin in the front-rear direction, as in the first embodiment.

  Further, according to the optical scanning device 10A of the second embodiment, even if the scanning range of the output light is enlarged in the rotation direction around the second axis a2, the distortion of the scanning range of the light is within an allowable range. be able to.

  The embodiments of the present invention have been described above.

  In the above embodiment, the configuration in which the output light of the light output unit 11 is directly incident on the reflection surface of the mirror 14 has been described as an example. However, the configuration may be such that the output light of the light output unit 11 is incident on the mirror 14 after the direction is changed by another optical element such as a mirror. With such a configuration, the arrangement of the light output unit 11 can be shifted from front to back and left and right, and the light emission direction from the light output unit 11 can be changed in various directions.

  Moreover, in the said embodiment, although the reflective surface of the mirror 14 is inclined so that the emitted light which injects from upper direction may be reflected in a horizontal direction, it is inclined so that the emitted light which injects from the lower part may be reflected in a horizontal direction You may let them.

  In the above embodiment, the configuration in which the movable frame and the movable portion of the actuator are supported by the linear spring has been described as an example. However, a configuration in which the movable frame and the movable portion are supported by the rotating shaft may be employed. The actuator may be a moving coil type actuator in which an electromagnetic coil is provided on either or both of the movable frame and the movable portion. Moreover, you may make it rotate a movable frame and a movable part using driving force, such as a motor, instead of electromagnetic force.

  The present invention can be used for an optical scanning device such as a laser radar, a scanning projector device, or a laser printer.

DESCRIPTION OF SYMBOLS 10, 10A Optical scanning device 11 Optical output part 12 Collimating lens 13 Beam splitter 14 Mirror 15 Optical filter 16 Condensing lens 17 Optical sensor 18 Optical sensor for monitoring 20 Actuator 21 Movable frame 22, 24 Linear spring 23 Movable part 27a, 27b Magnet 28, 29 Electromagnet a0 Optical axis a1 First axis a2 Second axis

Claims (5)

A movable frame that is supported rotatably about a first axis and rotates about the first axis;
A movable part that is supported by the movable frame in a state of being rotatable around a second axis and that rotates at a larger rotation angle than the movable frame;
A mirror disposed on the movable part;
A light output unit for generating output light;
With
The mirror has a reflecting surface inclined with respect to the second axis;
The optical axis of the output light incident on the reflecting surface has a direction component of the first axis that is higher than a direction component of the first axis and a direction component perpendicular to both the first axis and the second axis. Facing the big direction of the ingredients,
The irradiation direction of the output light reflected from the reflecting surface changes in two directions by rotation of the movable frame and rotation of the movable part.
Optical scanning device. The reflective surface has an inclination of 45 ° ± 15 ° with respect to the second axis;
The optical scanning device according to claim 1. With respect to the optical axis of the output light incident on the reflection surface, the direction in which the reflection surface approaches perpendicular is defined as a positive direction, and the direction away from vertical is defined as a negative direction.
The direction of the second axis is included in a range of + 15 ° to −5 ° with respect to the optical axis.
The optical scanning device according to claim 1 or 2. The direction of the first axis is included in a range of ± 15 ° in the horizontal direction,
The direction of the second axis is included in a range of ± 15 ° in the vertical direction.
The optical scanning device according to claim 1. The movable frame is supported by a first linear spring, and is configured to rotate around the first axis by twisting the first linear spring.
The movable portion is connected to the movable frame by a second linear spring, and is configured to rotate around the second axis by twisting the second linear spring.
The optical scanning device includes:
A first drive unit that applies a moment to the movable frame by electromagnetic force to rotate the movable frame;
A second drive unit that applies a moment to the movable unit by electromagnetic force to rotate the movable unit;
Comprising
The optical scanning device according to claim 1.