JP6460445B2 - Laser range finder - Google Patents

Description

  The present invention relates to a laser range finder for measuring a distance to an object.

  As a sensor for detecting an obstacle when the robot moves autonomously, or a sensor for detecting a person, for example, there is a laser range finder (LRF).

  The laser range finder measures the time from when the laser light is emitted until the reflected light reflected by the laser light hits the object, and calculates the distance to the object from the measurement result. The laser range finder measures the distance to an object in the entire range for measuring distance (hereinafter referred to as “scanning range”) by changing the direction in which the laser beam is emitted in the horizontal direction and the vertical direction. Do.

  As such a laser range finder, a motor has a structure in which an emission optical system for emitting laser light emitted from a light source from the laser range finder and a light receiving optical system for receiving reflected light from an object are integrated. Has been proposed (see, for example, Patent Document 1). The laser range finder acquires distance information from the phase difference between the reflected light from the object and the emitted light. In addition, the laser range finder further rotates a slit plate in which a plurality of slits are formed at predetermined intervals with the motor, and uses the number of pulses detected by a photo interrupter arranged on the rotation path of the slit plate. Get rotation angle information. Thereby, the laser range finder can calculate two-dimensional distance information.

JP 2009-63339 A

  However, in the case of a configuration using such a motor, the size of the motor depends on the weight of the optical system that is rotationally driven by the motor. Therefore, there is a problem that it is difficult to reduce the size of the laser range finder.

  In addition, a configuration using a scanner mirror (also referred to as a micromirror) that adjusts the emission direction of laser light has been proposed instead of a configuration using a motor.

  However, in the case of a scanner mirror that is small and driven at high speed, the effective diameter is as small as about 1 to 3 mm, and the amount of light that can be received by the light receiving element becomes weak because the amount of incident light is limited in the scanner mirror. Therefore, in this case, it is difficult to obtain sufficient measurement light intensity from a distant object as compared with a configuration using a motor. On the other hand, in order to obtain sufficient intensity of measurement light from a distant object, it is required that the effective diameter of the scanner mirror be, for example, on the order of several tens of mm. Therefore, it is difficult to reduce the size of the laser range finder.

  The present invention has been made to solve the above-described problems, and an object of the present invention is to provide a laser range finder that is small and can measure the distance of a far object.

  In order to achieve the above object, a laser range finder according to an aspect of the present invention is a laser range finder that measures a distance to an object, and includes a light source that emits laser light, and a swing shaft that extends in a predetermined direction. Is arranged on the optical path of the first reflected light, which is the reflected light from the object of the laser light from the oscillating mirror, and the oscillating mirror that scans the laser light from the light source. A first optical member that condenses the first reflected light on the oscillating mirror, and a second reflected light from the oscillating mirror of the first reflected light collected by the first optical member. A second optical member that is disposed on the optical path of the reflected light and collects the second reflected light; and a light receiving element that receives the second reflected light collected by the second optical member, 1 optical member and the second optical member The laser light output from the light source is disposed on the optical path and different positions until it is emitted to the outside of the laser range finder.

  Accordingly, the first optical member and the second optical member for condensing the reflected light from the object on the light receiving element are prevented from generating a part of the transmitted light or the reflected light that is not irradiated to the object. Therefore, it is possible to measure the distance of a distant object. Further, the laser beam can be scanned by the oscillating mirror to realize a reduction in size. That is, the laser range finder according to this aspect is small and can measure the distance of a far object.

  For example, the laser light emitted from the light source may be emitted outside the laser range finder without passing through a transmissive optical member.

  As a result, it is possible to more reliably reduce the return light that is part of the transmitted light or reflected light that is not irradiated onto the object.

  The first optical member and the second optical member may be disposed on opposite sides of the optical path of the laser light from the oscillating mirror in the predetermined direction.

  In addition, the first optical member and the second optical member are disposed at different positions in the predetermined direction, and laser light from the oscillating mirror is between the first optical member and the second optical member. And may be emitted to the outside of the laser range finder through the gap formed in

  Thereby, the laser range finder can be further downsized. In other words, the direction in which each of the light source, the first optical member, and the second optical member is viewed from the oscillating mirror can be substantially the same when viewed from the predetermined direction. The laser range finder can be further downsized as compared with the case where it is arranged.

  The laser beam from the light source may pass through the gap and reach the oscillating mirror.

  The second optical member may have a through hole through which the laser light from the light source passes and reaches the oscillating mirror.

  Thereby, the light of the 1st condensing member side can be condensed rather than the optical path of a laser beam in a predetermined direction. That is, the amount of reflected light guided to the light receiving element can be increased by collecting a wide range of light. Therefore, the distance measurement of the object located farther can be performed.

  In addition, the direction in which the first optical member is viewed from the oscillating mirror and the direction in which the second optical member is viewed from the oscillating mirror are different from each other when viewed from the predetermined direction. A plurality of sets of the first optical member and the second optical member are provided, and the first set and the second set of the plurality of sets are defined by the reflection surface of the oscillating mirror in the predetermined direction. You may arrange | position symmetrically about the normal line.

  As described above, by arranging a plurality of sets of the same optical system as a target, the reflected light from the target can be received more greatly. Therefore, the distance measurement of the object located farther can be performed.

  For example, the second optical member may be a second condensing lens that condenses light by transmitting the second reflected light.

  Further, for example, the second optical member may be a reflection mirror that collects light by reflecting the second reflected light.

  The second optical member emits parallel light in the predetermined direction by refracting the second reflected light by a positive action, and the laser range finder is further emitted from the second optical member. A third optical member for condensing the parallel light on the light receiving element may be provided.

  As a result, a bandpass filter (BPF :) that transmits light of a narrow band including the wavelength of laser light emitted from the light source and suppresses other light between the second optical member and the third optical member. Band Pass Filter) can be provided. Therefore, in this aspect, high ranging accuracy can be ensured by suppressing the influence of disturbance light. Here, in the BPF composed of the dielectric multilayer film, the transmittance has an incident angle dependency. Therefore, since the second optical member emits parallel light, the transmittance can be made equal even when a BPF composed of a dielectric multilayer film is used, thereby suppressing the influence of disturbance light. Thus, high ranging accuracy can be secured.

  Further, for example, the first optical member may be a toroidal lens having a condensing function only in the predetermined direction among the predetermined direction and an orthogonal direction orthogonal to the predetermined direction.

  According to the present invention, it is possible to measure the distance of a small and distant object.

1 is a perspective view showing an example of a schematic configuration of a laser range finder according to Embodiment 1. FIG. 3 is an optical path diagram showing a light receiving optical path of reflected light from an object of the laser range finder according to Embodiment 1. FIG. 6 is an optical path diagram in the YZ plane of the laser range finder according to Embodiment 1. FIG. 3 is a top view illustrating a configuration of a first condenser lens in Embodiment 1. FIG. FIG. 4B is an optical path diagram of the first condenser lens in the A-A ′ section and the B-B ′ section in FIG. 4A. FIG. 6 is an optical path diagram on the YZ plane of the second condenser lens in the first embodiment. FIG. 6 is an optical path diagram on the YZ plane of the third condenser lens in the first embodiment. 7 is a perspective view showing an example of a schematic configuration of a laser range finder according to Modification 1 of Embodiment 1. FIG. FIG. 10 is a top view showing an arrangement of a scanner mirror, a first condenser lens, and a second condenser lens in Modification 1 of Embodiment 1. FIG. 10 is a perspective view showing an example of a schematic configuration of a laser range finder according to Modification 2 of Embodiment 1. It is a figure which shows arrangement | positioning of a scanner mirror, a 1st condensing lens, and a 2nd condensing lens, and an optical path in the modification 2 of Embodiment 1. FIG. 6 is a perspective view illustrating an example of a schematic configuration of a laser range finder according to Embodiment 2. FIG. FIG. 6 is a perspective view showing a configuration of a condensing mirror in a second embodiment. 6 is an optical path diagram in the YZ plane of the laser range finder according to Embodiment 2. FIG. It is a figure explaining the effect which the laser range finder concerning Embodiment 2 shows.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. It should be noted that each of the embodiments described below shows a comprehensive or specific example. Numerical values, shapes, materials, constituent elements, arrangement positions and connection forms of constituent elements, and the like shown in the following embodiments are merely examples, and are not intended to limit the present invention. In addition, among the constituent elements in the following embodiments, constituent elements that are not described in the independent claims are described as arbitrary constituent elements. Each drawing does not necessarily show exactly each dimension or each dimension ratio.

(Embodiment 1)
Hereinafter, the laser range finder according to the first embodiment will be described with reference to FIGS.

[1. Overall configuration of laser range finder]
First, the configuration of the laser range finder 1 according to the present embodiment will be described with reference to FIG.

  FIG. 1 is a perspective view showing an example of a schematic configuration of a laser range finder 1 according to the first embodiment. FIG. 1 also shows an object 2 whose distance from the laser range finder 1 is measured by the laser range finder 1. FIG. 1 shows the inside of the housing 11 through the housing 11 of the laser range finder 1. In FIG. 1, the Z-axis direction is shown as an axis parallel to the scanning axis (reference direction) of the laser range finder 1, and the Y-axis is shown as a vertical direction (direction in which gravity acts in the installed state). . In the following description, the Y-axis direction is assumed to be the vertical direction. However, depending on the use mode, the Y-axis direction may not be the vertical direction, so the Y-axis direction is not limited to the vertical direction. The same applies to the following drawings.

  In the following, for example, the X axis direction plus side indicates the arrow direction side of the X axis, and the X axis direction minus side indicates the opposite side to the X axis direction plus side. The same applies to the Y-axis direction and the Z-axis direction.

  As shown in FIG. 1, the laser range finder 1 according to the present embodiment includes the following constituent members arranged inside a housing 11. Specifically, the laser range finder 1 includes a light source 10, a scanner mirror 20, a first condenser lens 30, a second condenser lens 40, a fixed mirror 50, a third condenser lens 60, and light reception. And an element 70. Although not shown, the laser range finder 1 further uses a phase difference between the laser light emitted from the light source 10 and the light received by the light receiving element 70 to obtain a distance to the object 2. Is provided.

  The light source 10 is, for example, a laser diode (LD: (Laser Diode)) that emits laser light 101. Specifically, the light source 10 is arranged so that the optical axis of the emitted laser beam 101 is inclined with respect to a plane perpendicular to the swing axis J of the scanner mirror 20, and the laser beam 101 is directed toward the scanner mirror 20. And exit. The light source 10 further includes a collimating lens that converts divergent light emitted from the LD into collimated light (parallel light), and emits laser light 101 that is parallel light.

  As shown in FIG. 1, the scanner mirror 20 swings around the swing axis J extending in a predetermined direction (vertical direction in the present embodiment) to scan the laser light 101 from the light source 10. It is an example of a mirror. That is, the scanner mirror 20 reflects the laser light 101 from the light source 10 as the scanning laser light 102 of the laser range finder 1. Thereby, the laser beam 102 is scanned in the scan area. The scanner mirror 20 is, for example, a MEMS mirror configured by forming a mirror, which is a minute mechanical component, on a silicon substrate on which an electronic circuit is formed.

  The first condenser lens 30 is arranged on the optical path of the first reflected light (the reflected light 103 in the present embodiment) that is the reflected light from the object 2 of the laser light 102 from the scanner mirror 20, and the first 2 is an example of a first optical member that focuses reflected light (reflected light 103) on a scanner mirror 20; The first condenser lens 30 is disposed at a position different from the optical path until the laser beam 101 emitted from the light source 10 is emitted to the outside of the laser range finder 1 (until it is emitted to the outside of the housing 11). Yes. Details of the first condenser lens 30 will be described later.

  The second condenser lens 40 is a second reflected light (this embodiment) that is a reflected light from the scanner mirror 20 of the first reflected light (the reflected light 104 in this embodiment) collected by the first condenser lens 30. Is an example of a second optical member that is disposed on the optical path of the reflected light 105) and collects the second reflected light (reflected light 105). Similar to the first condenser lens 30, the second condenser lens 40 is disposed at a position different from the optical path until the laser light 101 emitted from the light source 10 is emitted to the outside of the laser range finder 1. Yes. Details of the second condenser lens 40 will be described later.

  Here, “condensation” indicates that the light is refracted or reflected by an optical member having a positive power. That is, the optical member having a condensing function is an optical member having a positive power. Specifically, the first condensing lens 30 emits the reflected light 104 condensed on the scanner mirror 20 by condensing the reflected light 103 from the object 2 which is parallel light or divergent light. On the other hand, the second condensing lens 40 condenses the reflected light 105 which is diverging light from the scanner mirror 20 to emit parallel light 106.

  The fixed mirror 50 is a substantially flat mirror that is arranged on the optical path of the parallel light 106 and emits the parallel light 107 by reflecting the parallel light 106.

  The third condenser lens 60 is an example of a third optical member that condenses the parallel light 106 emitted from the second condenser lens 40 onto the light receiving element 70. Specifically, the third condensing lens is disposed on the optical path of the parallel light 107, and condenses the parallel light 106 emitted from the fixed mirror 50 onto the light receiving element 70, whereby the parallel light 106 is received by the light receiving element. Condensed to 70. Details of the third condenser lens 60 will be described later.

  The light receiving element 70 receives the reflected light 105 collected by the second condenser lens 40, for example, a photodiode (PD) or an avalanche photodiode (APD: Avalanche) having higher sensitivity than the photodiode. (Photo Diode). Specifically, the light receiving element 70 receives the parallel light 106 that is the reflected light 105 collected by the second condenser lens 40 via the fixed mirror 50 and the third condenser lens 60.

  The signal processing unit (not shown) uses the phase difference between the modulation signal included in the laser light emitted from the light source 10 and the modulation signal included in the light received by the light receiving element 70 to use the laser range finder 1. To the object 2 is calculated. That is, the signal processing unit uses the phase difference to calculate the time from when the laser light is emitted from the light source 10 until it is received by the light receiving element 70. This time is the time required for the laser light to reciprocate from the light source 10 to the measurement object. Therefore, the signal processing unit can obtain the distance by multiplying 1/2 of the time by the speed of light.

  The configuration of the laser range finder 1 according to the present embodiment has been described above.

  Here, the laser beams 101 and 102 are linearly polarized light having a relatively large light intensity. On the other hand, the reflected light 103 from the object 2 becomes diffused light having a very small light intensity when the laser light 102 is diffusely reflected by the object 2.

  Therefore, in the present embodiment, the reflected light 103 that is diffused light is condensed on the scanner mirror 20 as reflected light 104 by the first condenser lens 30. Further, the light reflected by the scanner mirror 20, that is, the reflected light 105 emanating from the scanner mirror 20 is condensed by the second condenser lens 40 and guided to the light receiving element 70. Thereby, in this Embodiment, sufficient light quantity which the light receiving element 70 can detect can be ensured.

  Furthermore, in the present embodiment, the first condensing lens 30 and the second condensing lens 40 pass through the optical path (hereinafter referred to as the output beam) until the laser beam 101 output from the light source 10 is emitted to the outside of the laser range finder 1. By arranging at a position different from the case where it is described as an optical path of light emission, a sufficient amount of light that can be detected by the light receiving element 70 can be ensured. That is, distance measurement can be performed even when the light intensity of the reflected light 103 from the target object 2 is very small because the target object 2 is located far away.

  Specifically, when the first condenser lens 30 and the second condenser lens 40 are arranged on the optical path of the emitted light, a part of the laser light 101 emitted from the light source 10 is part of the first condenser lens 30. And may be reflected by the second condenser lens 40. That is, the light of the laser beam 102 emitted from the laser range finder when the first condenser lens 30 and the second condenser lens 40 generate the return light of the transmitted light or the reflected light that is not irradiated to the object 2. The intensity may be smaller than the light intensity of the laser beam 101 emitted from the light source 10. In such a case, since the reflected light 103 from the object 2 is also reduced, there is a possibility that distance measurement of the distant object 2 cannot be performed.

  In contrast, in the present embodiment, by arranging the first condenser lens 30 and the second condenser lens 40 at positions different from the optical path of the emitted light, it is possible to suppress the generation of return light. The distance measurement of the distant object 2 can be performed.

[2. Optical system]
Next, the optical path of the laser range finder 1 according to this embodiment described above and the configuration of the components of the optical system will be described in detail with reference to FIGS. In the following, among the components of the optical system of the laser range finder 1, the configurations of the first condenser lens 30, the second condenser lens 40, and the third condenser lens 60 will be described in detail. Description of the system parts is omitted.

[2-1. Light receiving optical path]
First, the light receiving optical path of the reflected light 103 from the object 2 of the laser range finder 1 according to the present embodiment will be described with reference to FIG. FIG. 2 is an optical path diagram showing a light receiving optical path of the reflected light 103 from the object 2 of the laser range finder 1 according to the present embodiment. In the figure, for convenience of explanation, the optical path of the reflected light (reflected light 103, 104) until it enters the scanner mirror 20 and the reflected light (reflected light 105, parallel light) after being reflected by the scanner mirror 20 are shown. 106 and the optical path of the parallel light 107) are shown inverted around the scanner mirror 20.

  As shown in the figure, the reflected light 103 from the object 2 becomes reflected light 104 condensed on the scanner mirror 20 by the first condenser lens 30. Therefore, the reflected light 104 reflected by the scanner mirror 20 becomes reflected light 105 that is light that diverges from the scanner mirror 20. The reflected light 105 is condensed by the second condenser lens 40 to become parallel light 106 and is emitted from the second condenser lens 40. Thereafter, the parallel light 106 is reflected by the fixed mirror 50, becomes parallel light 107, is guided to the third condenser lens 60, and is then condensed on the light receiving element 70 by the third condenser lens 60.

  In order to configure such a light receiving optical path, each lens (the first condenser lens 30, the second condenser lens 40, and the third condenser lens 60) is required to have the following functions.

  That is, the first condenser lens 30 is required to have positive power in a direction parallel to the swing axis J of the scanner mirror 20 (in the vertical direction in the present embodiment) in the scanning angle range of the scanner mirror 20. It is done. The second condenser lens 40 is required to have a positive power in a direction parallel to the swing axis J. The third condenser lens 60 is required to have positive power.

  The surface shape of each lens that realizes such a function is preferably configured as follows in a cross section parallel to the vertical direction. Specifically, in the first condenser lens 30, the incident side surface of the reflected light 103 is a convex surface and the exit surface of the reflected light 104 is a flat surface. In the second condenser lens 40, the incident surface of the reflected light 105 is formed. Are parallel and the exit surface of the parallel light 106 is a convex surface. In the third condenser lens 60, the entrance surface of the parallel light 107 is preferably a convex surface, and the exit surface is preferably a flat surface or a convex surface. In the following, the surface shape of each lens will be described in this way. This surface shape is an example for satisfactorily correcting aberrations with a relatively small number of lenses (for example, three lenses). The surface shape of each lens is not limited to this as long as the power arrangement having such a function can be realized.

[2-2. Arrangement]
Next, the arrangement of the first condenser lens 30 and the second condenser lens 40 having the functions as described above will be described with reference to FIG. FIG. 3 is an optical path diagram in the YZ plane of the laser range finder 1 according to the present embodiment.

  As shown in the figure, the first condenser lens 30 and the second condenser lens 40 are arranged at positions different from the optical path until the laser light 101 emitted from the light source 10 is emitted to the outside of the laser range finder 1. Has been. That is, the laser beam 101 emitted from the light source 10 is emitted outside the laser range finder 1 without passing through the transmissive optical member.

  Specifically, as shown in FIGS. 1 and 3, the first condenser lens 30 and the second condenser lens 40 are arranged at different positions in the vertical direction. Here, the laser beam 101 from the light source 10 and the laser beam 102 from the scanner mirror 20 pass through a gap formed between the first condenser lens 30 and the second condenser lens 40, and then are laser range finder. 1 is emitted to the outside.

  Here, as shown in FIG. 3, in the optical paths a1 and a2 of the reflected light 103, the height of the optical path a1 (position on the plus side in the Y-axis direction) is higher than the height of the optical path a2 before entering the scanner mirror 20. However, after being reflected by the scanner mirror 20, the height of the optical path a1 becomes lower than the height of the optical path a2.

[2-3. Constitution]
Next, the structure of each lens (the 1st condensing lens 30, the 2nd condensing lens 40, and the 3rd condensing lens 60) in this Embodiment is demonstrated.

[2-3-1. First condenser lens]
First, the configuration of the first condenser lens 30 will be described with reference to FIGS. 4A and 4B. FIG. 4A is a top view showing the configuration of the first condenser lens 30 in the present embodiment. Specifically, FIG. 3 is a top view showing a configuration of the first condenser lens 30 viewed from the Y axis direction plus side. 4B is an optical path diagram of the first condenser lens 30 in the AA ′ section and the BB ′ section in FIG. 4A. 4A and 4B also show the scanner mirror 20 for convenience of explanation.

  As shown in FIG. 4A, the first condenser lens 30 does not have a condensing function in the horizontal direction (direction parallel to the XZ plane). Specifically, the first condenser lens 30 has substantially the same thickness in the horizontal direction.

  As shown in FIG. 4B, the first condenser lens 30 has a condensing function in the vertical direction and condenses the incident reflected light 103 near the center of the scanner mirror 20. Here, the cross-sectional shape when cut along the A-A ′ cross section in FIG. 4A and the cross-sectional shape when cut along the B-B ′ cross section in FIG. 4A are substantially the same. The cross-sectional shape of the first condenser lens 30 other than the A-A ′ cross section and the B-B ′ cross section of FIG. 4A is also substantially the same as FIG. 4B.

  The first condenser lens 30 is disposed above the optical path of the laser beam 102 (Y-axis direction plus side), and the first condenser lens 30 and the second condenser are disposed on the optical axis of the first condenser lens 30. A gap formed by the optical lens 40 is located.

  As such a 1st condensing lens 30, the toroidal lens which has a condensing effect | action only to a perpendicular | vertical direction can be used, for example among a perpendicular direction and a horizontal direction (direction parallel to XZ plane). Specifically, this toroidal lens has a toroidal surface which is a curved surface generated when a circle is rotated about a straight line that does not pass through the center thereof, the curvature of the cross-sectional shape when cut by the XZ plane, and the YZ plane. The curvatures of the cross-sectional shapes when cut at are different from each other.

[2-3-2. Second condenser lens]
Next, the configuration of the second condenser lens 40 will be described with reference to FIG. FIG. 5 is an optical path diagram in the YZ plane of the second condenser lens 40 in the present embodiment. For convenience of explanation, the scanner mirror 20 is also shown in FIG.

  As shown in the figure, the second condensing lens 40 has a condensing action in the vertical direction, and has reflected light 105 incident on the second condensing lens 40 having an divergence angle from the scanner mirror 20. By condensing, parallel light 106 is emitted.

  The second condenser lens 40 is disposed below the optical path of the laser beam 101 (minus side in the Y-axis direction), and the first condenser lens 30 and the second condenser are disposed on the optical axis of the second condenser lens 40. A gap formed by the optical lens 40 is located.

  As such a 2nd condensing lens 40, the cylindrical lens which has a condensing effect | action in a perpendicular | vertical direction can be used, for example. Specifically, this cylindrical lens has a shape in which a cylinder having a rotation axis parallel to the X-axis direction is divided by a plane parallel to the X-axis direction.

  The parallel light 106 emitted from the second condenser lens 40 is reflected by the fixed mirror 50, thereby becoming parallel light 107 having an optical axis different from that of the reflected light 105 and entering the third condenser lens 60. Incident.

[2-3-3. Third condenser lens]
Next, the configuration of the third condenser lens 60 will be described with reference to FIG. FIG. 6 is an optical path diagram in the YZ plane of the third condenser lens 60 in the present embodiment. In the figure, the light receiving element 70 is also shown for convenience of explanation.

  The third condenser lens 60 has a condensing function in both the X-axis direction and the Z-axis direction, and condenses the parallel light 107 incident from the fixed mirror 50 near the center of the light-receiving surface of the light-receiving element 70. 6 shows the cross-sectional shape of the third condenser lens 60 when cut along the YZ plane, the cross-sectional shape of the third condenser lens 60 when cut along the XY plane is also shown in FIG. It is almost the same.

  As such a 3rd condensing lens 60, a general convex lens symmetrical with an optical axis can be used, for example.

[3. Effect]
As described above, in the present embodiment, the scanner mirror 20 that scans the laser light 101 from the light source 10 is provided, and the first condenser lens 30 and the second condenser lens 40 are located at positions different from the optical path of the emitted light. Is arranged.

  Thereby, a part of transmitted light or reflected light that is not irradiated on the object 2 by the first condenser lens 30 and the second condenser lens 40 for condensing the reflected light 103 from the object 2 on the light receiving element 70. Since the generation of the return light can be suppressed, the distance measurement of the far object 2 can be performed. Further, by scanning the laser beam 102 with the scanner mirror 20, it is possible to reduce the size. That is, the laser range finder 1 according to the present embodiment can measure the distance of the object 2 that is small and far away.

  In the present embodiment, the laser beam 101 emitted from the light source 10 is emitted outside the laser range finder 1 without passing through the transmissive optical member.

  Thereby, generation | occurrence | production of the return light of the laser beam 101 radiate | emitted from the light source 10 can be suppressed more reliably.

  In the present embodiment, the first condenser lens 30 and the second condenser lens 40 are arranged on the opposite sides with respect to the optical path of the laser beam 101 from the scanner mirror 20 in the vertical direction. Specifically, the first condenser lens 30 and the second condenser lens 40 are arranged at different positions in a predetermined direction, and the laser light 101 from the scanner mirror 20 is transmitted to the first condenser lens 30 and the second condenser lens. The light passes through a gap formed between the optical lens 40 and is emitted to the outside of the laser range finder 1.

  Thereby, the laser range finder 1 according to the present embodiment can be further downsized. That is, the direction of viewing the light source 10, the first condenser lens 30, and the second condenser lens 40 from the scanner mirror 20 can be made substantially the same when viewed from the vertical direction (Y axis direction plus side). The laser range finder 1 can be further downsized as compared with the case where these are arranged in different directions as viewed from the direction.

  Further, in the present embodiment, the second condenser lens 40 emits parallel light by refracting the reflected light 105 by a positive action, and the laser range finder 1 further emits from the second condenser lens 40. A third condenser lens 60 that condenses the collimated light to the light receiving element 70 is provided.

  Accordingly, light having a narrow band wavelength including the wavelength of the laser light 101 emitted from the light source 10 is transmitted between the second condenser lens 40 and the third condenser lens 60, and other light is suppressed. A BPF can be provided. Therefore, the laser range finder 1 according to the present embodiment can secure high ranging accuracy by suppressing the influence of disturbance light. Here, in the BPF composed of the dielectric multilayer film, the transmittance has an incident angle dependency. Therefore, since the second condenser lens 40 emits parallel light, the transmittance can be made equal even when a BPF formed of a dielectric multilayer film is used. It is possible to secure high distance measurement accuracy by suppressing.

(Modification 1 of Embodiment 1)
Hereinafter, the laser range finder according to the first modification of the first embodiment will be described with reference to FIGS.

  FIG. 7 is a perspective view showing an example of a schematic configuration of a laser range finder 1A according to the first modification of the first embodiment. FIG. 7 shows the inside of the housing 11 through the housing 11 of the laser range finder 1A. In the figure, the fixed mirror 50, the third condenser lens 60, and the light receiving element 70 are not shown. FIG. 8 is a top view showing the arrangement of the scanner mirror 20, the first condenser lens 30, and the second condenser lens 40 in the first modification of the first embodiment. Specifically, the drawing shows the arrangement of the scanner mirror 20, the first condenser lens 30, and the second condenser lens 40 when viewed from the vertical direction (the Y axis direction plus side).

  The laser range finder 1A according to the present modification is substantially the same as the laser range finder 1 according to the first embodiment, but differs in the following points.

  Specifically, in the first embodiment, the direction in which the first condenser lens 30 is viewed from the scanner mirror 20 and the direction in which the second condenser lens 40 is viewed from the scanner mirror 20 are the vertical direction (Y-axis). It was substantially the same as seen from the direction plus side). That is, in the first embodiment, the optical axis of the first condenser lens 30 and the optical axis of the second condenser lens 40 are substantially the same as viewed from the vertical direction (Y-axis direction plus side). It was.

  On the other hand, in this modification, as shown in FIGS. 7 and 8, the direction when the first condenser lens 30 is viewed from the scanner mirror 20 and the direction when the second condenser lens 40 is viewed from the scanner mirror 20. Are different from each other when viewed from the vertical direction (Y-axis direction plus side). That is, in the present modification, the optical axis of the first condenser lens 30 and the optical axis of the second condenser lens 40 are different from each other when viewed from the vertical direction.

  In the laser range finder 1A according to this modification configured as described above, the first condenser lens 30 and the second condenser lens 40 are also emitted from the light source 10 as in the first embodiment. Since 101 is arranged at a position different from the optical path until the laser beam is emitted to the outside of the laser range finder 1A, the same effect as in the first embodiment can be obtained.

  In addition, the direction in which the first condenser lens 30 is viewed from the scanner mirror 20 and the direction in which the second condenser lens 40 is viewed from the scanner mirror 20 are different from each other when viewed from the vertical direction (Y axis direction plus side). Thereby, the freedom degree of arrangement | positioning of the 1st condensing lens 30 and the 2nd condensing lens 40 improves.

(Modification 2 of Embodiment 1)
Hereinafter, a laser range finder according to Modification 2 of Embodiment 1 will be described with reference to FIGS. 9 and 10.

  FIG. 9 is a perspective view illustrating an example of a schematic configuration of a laser range finder 1B according to the second modification of the first embodiment. This figure shows the inside of the housing 11 through the housing 11 of the laser range finder 1B. Further, in the same figure, the light source 10, the fixed mirror 50, the third condenser lens 60, and the light receiving element 70 are not shown. FIG. 10 is a diagram illustrating the arrangement of the scanner mirror 20, the first condenser lenses 30A and 30B, the second condenser lenses 40A and 40B, and the optical paths a1 to a4 in the second modification of the first embodiment. In the figure, for convenience of explanation, the optical path of the light incident on the scanner mirror 20 and the optical path of the light reflected and emitted from the scanner mirror 20 are inverted with respect to the scanner mirror 20. In addition, the first condensing lenses 30A and 30B show a cross-sectional shape when cut in the vertical direction including the optical path of the laser light 101, and the second condensing lenses 40A and 40B include the optical path of the laser light 102. The cross-sectional shape when cut in the vertical direction is shown.

  As shown in FIGS. 9 and 10, the laser range finder 1 </ b> B according to the present modification includes two sets of the first condenser lens 30 and the second condenser lens 40 in the first modification of the first embodiment. It is. The first condenser lenses 30A and 30B in the present embodiment correspond to the first condenser lens 30 in the first modification of the first embodiment, and the second condenser lenses 40A and 40B are the same as those in the first embodiment. This corresponds to the second condenser lens 40 in the first modification of the first embodiment.

  In other words, in the present modification, a plurality of sets of the first condenser lens 30 and the second condenser lens 40 having different directions viewed from the scanner mirror 20 as viewed from the vertical direction (Y-axis direction plus side). (Two sets in this modification) are provided. Specifically, the laser range finder 1B according to this modification includes a first set of a first condenser lens 30A and a second condenser lens 40A, a first condenser lens 30B, and a second condenser lens. And a second set of 40B.

  Here, the first set and the second set are arranged symmetrically about the normal line of the reflecting surface of the scanner mirror 20 in the vertical direction. In other words, the laser range finder 1B according to this modification has a configuration in which the same optical system is arranged vertically. Specifically, the reflected lights 103A and 103B from the object 2 are condensed on the scanner mirror 20 by the first condenser lenses 30A and 30B of each group (first group and second group). The light emitted from the scanner mirror 20 with a divergence angle by being reflected by the scanner mirror 20 is condensed by the second condenser lenses 40A and 40B of each group (first group and second group). As a result, parallel light 106A, 106B is emitted from the second condenser lenses 40A, 40B, and the light receiving element is passed through a fixed mirror (not shown) and a third condenser mirror (not shown). (Not shown).

  Thus, in this modification, the reflected light from the target object 2 can be received more greatly by arranging a plurality of sets of the same optical system on the upper and lower targets. Therefore, the distance measurement of the object 2 located farther can be performed.

  Here, as shown in FIG. 3, the heights (positions on the Y axis direction plus side) of the optical paths a1 and a2 of the reflected light 103A and the optical paths a3 and a4 of the reflected light 103B are high before entering the scanner mirror 20. The optical path a1, the optical path a2, the optical path a3, and the optical path a4 are sequentially arranged.

  In the laser range finder 1B according to this modified example configured as described above, the first condenser lenses 30A and 30B and the second condenser lenses 40A and 40B are emitted from the light source 10 as in the first embodiment. Since the laser beam 101 thus arranged is arranged at a position different from the optical path until the laser beam 101 is emitted to the outside of the laser range finder 1B, the same effects as those of the first embodiment can be obtained.

  In the present modification, the configuration in which two sets of the same optical system are arranged has been described as an example. However, the configuration is not limited thereto, and a configuration in which three or more sets of the same optical system are arranged may be used.

(Embodiment 2)
Hereinafter, the laser range finder according to the second embodiment will be described with reference to FIGS.

  FIG. 11 is a perspective view showing an example of a schematic configuration of the laser range finder 201 according to the second embodiment. In addition, the target object 2 by the laser range finder 201 is also shown in FIG. FIG. 11 shows the inside of the housing 11 through the housing 11 of the laser range finder 201. FIG. 12 is a perspective view showing a configuration of a condenser mirror 240 (described later) in the second embodiment.

  As shown in FIG. 11, the laser range finder 201 according to the present embodiment is substantially the same as the laser range finder 1 according to the first embodiment, but includes a condensing mirror 240 instead of the second condensing lens 40. The point is different. Hereinafter, the laser range finder 201 according to the present embodiment will be described focusing on differences from the laser range finder 1 according to the first embodiment.

  The condensing mirror 240 is a second reflected light (this embodiment) that is a reflected light from the scanner mirror 20 of the first reflected light (the reflected light 104 in this embodiment) collected by the first condenser lens 30. Then, it is an example of the 2nd optical member which is arrange | positioned on the optical path of the reflected light 105), and condenses the said 2nd reflected light (reflected light 105). As shown in FIGS. 11 and 12, the condensing mirror 240 has a through hole 241 through which the laser light 101 from the light source 10 passes and reaches the scanner mirror 20. As the condensing mirror 240, for example, a configuration in which a through hole 241 is formed in a cylindrical concave mirror having a condensing function in the vertical direction can be used.

  Next, the arrangement of the first condenser lens 30 and the condenser mirror 240 will be described with reference to FIGS. 11 and 13. FIG. 13 is an optical path diagram in the YZ plane of the laser range finder 201 according to the present embodiment.

  As shown in FIGS. 11 and 13, the first condenser lens 30 and the condenser mirror 240 are located at positions different from the optical path until the laser light 101 emitted from the light source 10 is emitted to the outside of the laser range finder 201. Has been placed. That is, the laser beam 101 emitted from the light source 10 is emitted to the outside of the laser range finder 201 without passing through the transmissive optical member.

  Specifically, as shown in FIGS. 11 and 13, the first condenser lens 30 and the condenser mirror 240 are arranged at different positions in the vertical direction. Here, unlike the first embodiment, the laser beam 101 from the light source 10 passes through the through-hole 241 formed in the condensing mirror 240 and reaches the scanner mirror 20. On the other hand, the laser beam 102 from the scanner mirror 20 passes through the gap formed between the first condenser lens 30 and the condenser mirror 240 in the same manner as in the first embodiment, and is outside the laser range finder 201. Is emitted.

  Further, the condensing mirror 240 has a condensing action in the vertical direction, and has a divergence angle from the scanner mirror 20 and condenses the reflected light 105 incident on the second condensing lens 40, thereby being parallel. Light 206 is emitted.

  As described above, according to the laser range finder 201 according to the present embodiment, the first condenser lens 30 and the condenser mirror 240 cause the laser light 101 emitted from the light source 10 to be outside the laser range finder 201. By being arranged at a position different from the optical path until the light is emitted, the same effect as in the first embodiment can be obtained.

  Further, according to the laser range finder 201 according to the present embodiment, the condensing mirror 240 has the through hole 241 through which the laser light 101 from the light source 10 passes and reaches the scanner mirror 20. The effect produced by this will be described with reference to FIG. FIG. 14 is a diagram for explaining an effect produced by the laser range finder 201 according to the second embodiment. Specifically, this figure is an optical path diagram in the YZ plane of the condensing mirror 240 in the present embodiment.

  As shown in the figure, the condensing mirror 240 adds to the reflected light passing through the optical paths a1 and a2 below the optical path of the laser light 101 (minus side in the Y-axis direction) out of the reflected light 105 from the scanner mirror 20. Further, the reflected light passing through the optical path a3 above (Y axis direction plus side) above the optical path of the laser beam 101 can be collected. That is, the amount of parallel light 206 guided to the light receiving element 70 can be increased. Therefore, according to the laser range finder 201 according to the present embodiment, it is possible to measure the distance of the object 2 located farther away.

  Note that the end of the condensing mirror 240 on the first condensing lens 30 side may be a horizontal plane close to the scanning region of the laser light 102. That is, the end surface of the condensing mirror 240 on the first condensing lens 30 side may be formed by a horizontal plane (a plane parallel to the YZ plane).

(Other embodiments)
Although the laser range finder according to the embodiments of the present invention has been described above, the present invention is not limited to these embodiments and modifications.

  For example, in the above description, the laser beam 101 emitted from the light source 10 directly reaches the scanner mirror 20, but the laser beam 101 reaches the scanner mirror 20 via an optical member such as a mirror and a prism. Also good. That is, the laser beam 101 may reach the scanner mirror 20 indirectly.

  However, by causing the laser beam 101 to reach the scanner mirror 20 directly, stray light due to surface reflection of the optical component that causes noise in the distance measurement signal can be suppressed.

  In the above description, the first condensing lens is described as an example of the first optical member that condenses the reflected light 103 on the scanner mirror 20, but the first optical member is not limited thereto. For example, as the first optical member, a mirror having the above-described toroidal surface as a reflection surface may be used, or a plurality of mirrors may be combined.

 In the above description, the third condensing lens 60 is described as an example of the third optical member that condenses the parallel light 107, but the third optical member is not limited thereto. For example, as the third optical member, a mirror that focuses the light receiving element 70 by reflecting parallel light may be used.

  In the above description, the reflected light 105 is refracted with positive power by the second optical member to be converted into the parallel light 106 and then condensed on the light receiving element 70 by the third condenser lens 60. Instead of providing 60, the light may be condensed on the light receiving element 70 by the second optical member.

  Furthermore, the above embodiment and the above modification examples may be combined.

  The present invention is applicable to a laser range finder that measures the distance of an object, a shape measuring device that measures the shape of the object by measuring the distance of the object, and the like.

1, 1A, 1B, 201 Laser range finder 2 Object 10 Light source 11 Housing 20 Scanner mirror (oscillating mirror)
30, 30A, 30B First condenser lens (first optical member)
40, 40A, 40B Second condenser lens (second optical member)
50 Fixed mirror 60 Third condenser lens (third optical member)
70 light receiving element 240 condensing mirror (first optical member)
241 Through hole J Oscillating shaft 101, 102 Laser light 103-105 Reflected light 106, 106A, 106B, 107, 206 Parallel light

Claims (7)

A laser range finder that measures the distance to an object,
A light source that emits laser light;
A swing mirror that scans the laser light from the light source by swinging about a swing shaft extending in a predetermined direction;
A first optical member that is disposed on an optical path of first reflected light that is reflected light from the object of the laser light from the oscillating mirror and condenses the first reflected light on the oscillating mirror;
The second optical member that is disposed on the optical path of the second reflected light that is the reflected light from the oscillating mirror of the first reflected light collected by the first optical member and collects the second reflected light. When,
A light receiving element that receives the second reflected light collected by the second optical member,
The first optical member and the second optical member are disposed at a position different from an optical path until the laser light output from the light source is emitted to the outside of the laser range finder,
The first optical member and the second optical member are arranged on opposite sides of the optical path of the laser light from the oscillating mirror in the predetermined direction,
The first optical member and the second optical member are arranged at different positions in the predetermined direction,
Laser light from the oscillating mirror passes through a gap formed between the first optical member and the second optical member and is emitted to the outside of the laser range finder.
The second optical member has a through-hole through which laser light from the light source passes and reaches the oscillating mirror. Laser range finder. The laser range finder according to claim 1, wherein the laser light emitted from the light source is emitted to the outside of the laser range finder without passing through a transmissive optical member. A laser range finder that measures the distance to an object,
A light source that emits laser light;
A swing mirror that scans the laser light from the light source by swinging about a swing shaft extending in a predetermined direction;
A first optical member that is disposed on an optical path of first reflected light that is reflected light from the object of the laser light from the oscillating mirror and condenses the first reflected light on the oscillating mirror;
The second optical member that is disposed on the optical path of the second reflected light that is the reflected light from the oscillating mirror of the first reflected light collected by the first optical member and collects the second reflected light. When,
A light receiving element that receives the second reflected light collected by the second optical member,
The first optical member and the second optical member are disposed at a position different from an optical path until the laser light output from the light source is emitted to the outside of the laser range finder,
The first optical member and the second optical member are arranged on opposite sides of the optical path of the laser light from the oscillating mirror in the predetermined direction,
The direction in which the first optical member is viewed from the oscillating mirror and the direction in which the second optical member is viewed from the oscillating mirror are different from each other when viewed from the predetermined direction.
The laser range finder includes a plurality of sets each including the first optical member and the second optical member,
Of the plurality of sets, the first set and the second set are arranged symmetrically about the normal line of the reflecting surface of the oscillating mirror in the predetermined direction. The second optical member, the laser range finder according to any one of claims 1 to 3 as a second condensing lens for focusing transmitted through the second reflection light. The second optical member, the laser range finder according to any one of claims 1 to 3, which is a reflecting mirror for condensing light by reflecting the second reflected light. The second optical member emits parallel light in the predetermined direction by refracting the second reflected light by a positive action;
The laser range finder according to any one of claims 1 to 5 , wherein the laser range finder further includes a third optical member that condenses the parallel light emitted from the second optical member on the light receiving element. Wherein the first optical member, the predetermined direction, and, among the direction orthogonal to the predetermined direction, according to any one of claim 1 to 6, which is a toroidal lens having a condensing effect only in the predetermined direction Laser range finder.

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