Optical device, optical system, and moving apparatus

Abstract

To provide an optical device and the like capable of achieving space saving or compactness while simplifying a structure.SOLUTION: An optical device 1 includes a deflection unit 16 and an optical element 14. The deflection unit 16 deflects illumination light emitted from a light emitting unit 11 to scan an object OBJ and also deflects reflected light from the object OBJ. The optical element 14 guides the illumination light from the light emitting unit 11 to the deflection unit 16 by allowing the illumination light to pass through a light guide structure from a first surface S1 to a second surface S2. The optical element 14 also guides the reflected light from the deflection unit 16 to a light receiving unit 12 by allowing the reflected light to enter from the second surface S2 and transmit through the first surface S1.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present invention relates to an optical device such as a LiDAR (Light Detection and Ranging) system. [Background technology]

[0002] An optical device has been proposed that constitutes a LiDAR system mounted on a vehicle and detects targets (objects) such as pedestrians, preceding vehicles, and oncoming vehicles ahead of the vehicle, and aims to simplify the configuration and suppress the generation of unnecessary light (see, for example, Patent Document 1). The optical device includes a deflection unit and an optical element. The deflection unit deflects illumination light from the light-emitting unit to scan an object, and also deflects reflected light from the object. The optical element guides illumination light from the light-emitting unit to the deflection unit, and guides reflected light from the deflection unit to the light-receiving unit.

[0003] The optical element has a first surface and a second surface. Illumination light from the light-emitting unit is incident on the first surface. The second surface includes a transmissive region through which the illumination light from the first surface passes and a reflective region through which reflected light from the deflection unit is reflected. The illumination light from the first surface enters the transmissive region without passing through any other surface. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Publication No. 2020-122689 Summary of the Invention [Problem to be solved by the invention]

[0005] However, in this prior art, the light-emitting unit and the light-receiving unit are arranged in different directions relative to the optical element and / or deflector, so a larger space must be secured for the optical device. Furthermore, the reflectivity of the reflective area of ​​the second surface (which functions as a polarizing beam splitter) is low, at around 50%, and the number of lens components tends to increase.

[0006] SUMMARY OF THE INVENTION It is therefore an object of the present invention to provide an optical device or the like that can be simplified in configuration while saving space or being made compact. [Means for solving the problem]

[0007] The optical device of the present invention comprises: a deflection unit that deflects illumination light from a light emitting unit to scan an object and deflects reflected light from the object; and an optical element that guides the illumination light from the light-emitting unit to the deflection unit by passing it through a light-guiding structure from the first surface to the second surface, and guides the reflected light from the deflection unit to the light-receiving unit by making it incident on the second surface and transmitting it through the first surface.

[0008] According to an optical device having this configuration, the optical device can be made more compact and space-saving than when the light-emitting section and the light-receiving section are arranged to face each other with the optical element in between. [Brief explanation of the drawings]

[0009] [Figure 1] 1 is an explanatory diagram of the configuration of a vehicle (movement device) according to a first embodiment of the present invention. [Figure 2] FIG. 1 is a diagram illustrating the configuration of an optical device according to a first embodiment of the present invention. [Figure 3] FIG. 1 is a diagram illustrating the configuration of an optical element according to a first embodiment of the present invention. [Figure 4] FIG. 4 is an explanatory diagram of the configuration of an optical element according to a second embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0010] (First embodiment) 1, an optical system including an optical device 1 and a control device 100 is mounted on a vehicle 2, which is a moving device according to one embodiment of the present invention. The optical device 1 is accommodated inside a housing of a headlight 22 of the vehicle 2, together with a headlight light source (a light source that irradiates the front with white visible light). The optical device 1 may be attached to a location on the vehicle body below the headlight 22.

[0011] The moving device may be a vehicle 2 (four-wheeled vehicle), a two-wheeled vehicle, or a robot with a moving function (or an autonomous moving function). The vehicle 2 may be a vehicle driven by a person or an automatically driven vehicle.

[0012] 2 is a schematic diagram of an optical device 1 according to a first embodiment of the present invention, taken along a cross section including its optical axis (a cross section parallel to the xy plane). The optical device 1 includes a substrate 10, a light-emitting unit 11, a light-receiving unit 12, an optical element 14, and a deflection unit 16. In FIG. 2, the optical path (illumination optical path) of illumination light from the light-emitting unit 11 traveling toward an object OBJ is indicated by a dashed-dotted arrow, and the optical path (receiving optical path) of reflected light from the object OBJ traveling toward the light-receiving unit 12 is indicated by a dashed-two-dotted arrow. In this embodiment, the light-emitting unit 11 and the light-receiving unit 12 are mounted on the same substrate 10.

[0013] The optical device 1 is used as a detection device and an imaging device that detects and images an object OBJ by receiving light reflected from the object OBJ, as well as a distance measuring device that obtains information about the distance to the object OBJ. The optical device 1 employs a technology called LiDAR (Light Detection and Ranging), which calculates the distance to the object OBJ based on the time it takes to receive the light reflected from the object OBJ or the phase of the reflected light.

[0014] The light-emitting unit 11 has, for example, a semiconductor laser as a light source, which has high energy concentration and high directivity. The semiconductor laser emits, for example, infrared light (e.g., illumination light with a wavelength of 905 nm, which is included in the near-infrared range) that has little effect on the human eye. The smaller the light emission surface of the light source used in the light-emitting unit, the better the directivity. One example is a PCSEL (Photonic-Crystal Surface-Emitting Laser). A PCSEL has high directivity of less than 1° immediately after emission. This makes it possible to configure a LiDAR unit with a minimal configuration without using a collimating lens.

[0015] 2, optical element 14 is a single optical element made of a single material that branches an illumination light path (see dashed dotted line) and a light receiving light path (see dashed two dotted line) and guides illumination light from light emitter 11 to deflector 16 and guides reflected light from deflector 16 to light receiver 12. It is desirable that the material of optical element 14 has a sufficiently high transmittance for the wavelength of illumination light.

[0016] 3, the optical element 14 has a first surface S1 and a second surface S2, which are substantially aspherical, that refract and collect the reflected light from the deflection unit 16 toward the light receiving unit 12. The first surface S1 and the second surface S2 are part of a convex lens shape having a focal point near the light receiving unit 12.

[0017] As shown in Fig. 3, the first surface S1 has an incident region S11 of illumination light and a transmission region S12 of reflected light. The optical element 14 has a first convex portion 141 that locally protrudes from the first surface S1. As a result, a "first local surface" that is a plane locally perpendicular to the traveling direction (+y direction) of illumination light from the light-emitting unit 11 is formed on the first surface S1 as the incident region S11 of illumination light. As shown in Fig. 3, the incident region S11 of illumination light and the transmission region S12 of reflected light are arranged adjacent to or continuous with each other. As shown in Fig. 3, the end P of the incident region S11 of illumination light is 1+ and P 1-One end P of 1- and the end P of the transmission region S12 of the reflected light. 2+ and P 2- One end P of 2+ The positions of the first surface S1 of the optical element 14 may be provided with an anti-reflection film to reduce reflectance and improve transmittance.

[0018] As shown in FIG. 3, the second surface S2 has an illumination light transmission region S21 and a reflected light incidence region S22. The optical element 14 has a second convex portion 142 that locally protrudes from the second surface S2. The first convex portion 141 and the second convex portion 142 are arranged at the same or substantially the same position in a direction perpendicular to the propagation direction of the illumination light (±x direction). As a result, a "second local surface," which is a plane locally perpendicular to the propagation direction of the illumination light from the light-emitting unit 11 (+y direction), is formed on the second surface S2 as the illumination light transmission region S12. As shown in FIG. 3, the illumination light transmission region S21 is arranged approximately in the center of the reflected light incidence region S22. An anti-reflection film may be provided on the second surface S2 of the optical element 14 to reduce reflectance and improve transmittance.

[0019] As described above, the first convex portion 141 and the second convex portion 142 are formed on the optical element 14, thereby forming a "light-guiding structure" that allows the illumination light from the light-emitting portion 11 to pass from the incident region S11 of the first surface S1 to the transmitting region S21 of the second surface S2 with almost no change in directionality before it is incident on the first surface S1 and after it passes through the second surface S2.

[0020] The deflection unit 16 deflects illumination light from the optical element 14 to scan the object OBJ, and also deflects reflected light from the object OBJ and guides it to the optical element 14. The deflection unit 16 is composed of a single drive mirror 162. The drive mirror 162 is preferably capable of swinging around at least two axes (a two-axis drive mirror) to enable two-dimensional scanning of the object OBJ. For example, a galvanometer mirror or a MEMS (Micro Electro Mechanical System) mirror may be used as the drive mirror 162. The drive mirror 162 is, for example, a MEMS mirror that is capable of swinging along both the x-axis and z-axis (with a swing angle of up to ±15° and a swing frequency of up to 1 kHz).

[0021] The light receiving unit 12 is an element (sensor) for receiving light from the optical element 14, performing photoelectric conversion, and outputting a signal. The optical element 20 is a PD (Photo Diode), APD (Avalanche Photo Diode), SPAD (Single Photodiode), or the like. le The light receiving unit 12 may include an optical filter member (a bandpass filter) that transmits only desired light and blocks (absorbs) other unwanted light. The light reflected from the object OBJ illuminated by the illumination light is deflected by the deflection unit 16, enters the incident area S22 of the second surface S2 of the optical element 14, and then passes through the transmission area S12 of the first surface S1 before entering the light receiving unit 12. The light receiving unit 12 may include an optical filter member (a bandpass filter) that transmits only desired light and blocks (absorbs) other unwanted light.

[0022] The control device 100 is configured to control the operation of the onboard devices of the vehicle 2 as well as the operation of the optical device 1. The control device 100 includes an arithmetic processing device (e.g., a CPU, a processor core, etc.) and a storage device (memory, etc.). The control device 100 is configured so that the arithmetic processing device (hardware) reads a program (software) and data from the storage device and performs arithmetic processing on the data in accordance with the program, thereby executing a designated task. The control device 100 is configured to drive each of the light-emitting unit 11 and the drive mirror 162 at a designated drive voltage and / or a designated drive frequency, and to control the output of the light-emitting unit 11 (the amount of illumination light). The control device 100 can also pulse the illumination light by controlling the operation of the light-emitting unit 11, or generate signal light by intensity-modulating the illumination light.

[0023] 2, the control device 100 includes a distance information acquisition unit 110 and a contact determination unit 120. Each of the distance information acquisition unit 110 and the contact determination unit 120 is configured to execute a designated task by having an arithmetic processing device (hardware) read a program (software) and data from a storage device and perform arithmetic processing on the data in accordance with the program.

[0024] The distance information acquisition unit 110 is configured to acquire distance information of the object OBJ based on the time from when illumination light is emitted from the light-emitting unit 11 (light-emitting time) to when the light-receiving unit 12 receives the light reflected from the object OBJ (light-receiving time). The distance information acquisition unit 110 may acquire a signal from the light-receiving unit 12 at a specified frequency. In addition to or instead of the time until the light reflected from the object OBJ is received, the distance information acquisition unit 110 may acquire distance information based on the phase of the light reflected from the object OBJ. Specifically, the distance information acquisition unit 110 may acquire the difference (phase difference) between the phase of the signal from the light-emitting unit 11 and the phase of the signal output from the light-receiving unit 12, and multiply the phase difference by the speed of light to acquire the distance information of the object OBJ.

[0025] The contact determination unit 120 is configured to determine the likelihood of contact between the object OBJ and the vehicle 2 based on distance information of the object OBJ, such as other vehicles, pedestrians, and other traffic participants as well as roadside structures, acquired by the distance information acquisition unit 110. When the contact determination unit 120 determines that there is a high likelihood of contact between the vehicle 2 and the object OBJ, the control device 100 may be configured to decelerate, stop, or change direction (steer) the vehicle 2, or to output an alert to alert passengers of the vehicle 2.

[0026] According to the optical device 1 having this configuration, the light emitting unit 11 and the light receiving unit 12 can be arranged close to each other to such an extent that the deviation of the azimuth angles of the respective positions of the light emitting unit 11 and the light receiving unit 12 relative to the optical element 14 falls within the range of (1++°-90°) to (1△△°-90°). This allows the light emitting unit 11 and the light receiving unit 12 to be mounted on the same substrate 10, as shown in FIG.

[0027] Specifically, as shown in FIG. 3, the point (incident area S11) on the first surface S1 of the optical element 14 through which the illumination light from the light-emitting unit 11 passes is used as a reference, and the distal end P of the transmission area S12 of the reflected light from the object OBJ on the first surface S1 of the optical element 14 is 2- (the distance w in the direction perpendicular to the direction of travel of the illumination light (±x direction)) and the distal end P of the transmission region S12 2- Based on the distance from the light emitting unit to the light receiving unit 12 (distance d2 in a direction parallel to the direction of travel of the illumination light), the light emitting unit and the light receiving unit can be arranged close enough together that the spacing between them is w+d2|tanθ| (θ=1++° to 1△△°).

[0028] Therefore, compared to a case where the light emitting section 11 and the light receiving section 12 are arranged to face each other with the optical element 14 interposed therebetween, the optical device 1 can be made more space-saving and compact.

[0029] (Second embodiment) The optical device 1 according to the second embodiment of the present invention differs from the first embodiment only in the configuration of the optical element 14, particularly the configuration of the light guide structure, and therefore the following description will focus mainly on this difference. Components common to the first and second embodiments will be designated by the same reference numerals and detailed descriptions will be omitted.

[0030] As shown in Fig. 4, the first surface S1 has an illumination light incident region S11 and a reflected light transmission region S12. The second surface S2 has an illumination light transmission region S21 and a reflected light incident region S22. The illumination light incident region S11 and transmission region S21 are arranged at the same position or approximately the same position in a direction perpendicular to the direction of propagation of the illumination light (±x direction). The optical element 14 has a through-hole 140 extending between the illumination light incident region S11 on the first surface S1 and the illumination light transmission region S21 on the second surface S2. In the second embodiment, the through-hole 140 forms a "light guide structure."

[0031] (Another embodiment of the present invention) In the first embodiment, the first convex portion 141 that locally protrudes (in the -y direction) on the first surface S1 is formed on the optical element 14, thereby forming a "first local surface" that is a plane locally perpendicular to the traveling direction (+y direction) of the illumination light from the light-emitting unit 11 as the illumination light incident region S11 on the first surface S1 (see FIG. 3). In other embodiments, the "first local surface" may be formed by forming a first concave portion that is locally recessed in the +y direction on the first surface S1 on the optical element 14. The depth of the first concave portion is appropriately selected, and may be, for example, approximately ½, ⅓, or ¼ the depth of the through-hole 140 that constitutes the light-guiding structure in the second embodiment.

[0032] In the first embodiment, the second convex portion 142 locally protruding (in the +y direction) on the second surface S2 is formed on the optical element 14, thereby forming a "second local surface" that is a plane locally perpendicular to the traveling direction (+y direction) of the illumination light from the light-emitting unit 11 as the illumination light transmission region S21 on the second surface S2 (see FIG. 3). In other embodiments, the "second local surface" may be formed by forming a second concave portion locally recessed in the -y direction on the second surface S2 on the optical element 14. The depth of the second concave portion is appropriately selected and may be, for example, approximately ½, ⅓, or ¼ the depth of the through-hole 140 constituting the light-guiding structure in the second embodiment. [Explanation of symbols]

[0033] 1‥Optical device 10. Circuit board 11. Light-emitting part 12‥Light receiving part 14. Optical elements 140...Through hole 141...First convex part 142...Second convex part 16‥Deflection part 162...Driving mirror 2. Vehicles (mobile devices) 22. Headlight OBJ‥object S1‥First page S11: Illumination light incident area (first local surface) S12: Reflected light transmission area S2‥Second side S21: Illumination light transmission area (second local surface) S22: Area of ​​incidence of reflected light.

Claims

1. a deflection unit that deflects illumination light from a light emitting unit to scan an object and deflects reflected light from the object; an optical element that guides the illumination light from the light-emitting unit to the deflection unit by passing the illumination light from the light-emitting unit through a light-guiding structure from a first surface to a second surface, and guides the reflected light from the deflection unit to a light-receiving unit by making the reflected light incident on the second surface and transmitting it through the first surface. optical equipment.

2. 2. The optical device according to claim 1, The light guide structure extends between a portion of a transmission region of the reflected light on the first surface and a portion of an incidence region of the reflected light on the second surface. optical equipment.

3. 3. The optical device according to claim 2, The light guide structure extends between an end of a transmission region of the reflected light on the first surface and a part of an incidence region of the reflected light on the second surface. optical equipment.

4. 2. The optical device according to claim 1, The light guide structure extends between a portion of the first surface that is outside a transmission region of the reflected light and a portion of an incidence region of the reflected light on the second surface. optical equipment.

5. 2. The optical device according to claim 1, The light guide structure is configured by a first localized surface formed on the first surface locally perpendicular to the incident direction of the illumination light from the light emitting unit, and a second localized surface formed on the second surface locally perpendicular to the transmission direction of the illumination light. optical equipment.

6. 2. The optical device according to claim 1, The light guide structure is formed by a through passage extending from the first surface to the second surface. optical equipment.

7. 2. The optical device according to claim 1, The light emitting unit and the light receiving unit are mounted on a single substrate. optical equipment.

8. The optical device according to claim 1; a distance information acquisition unit that acquires distance information of the object based on the output of the light receiving unit. Optical system.

9. 9. The optical system of claim 8, a contact determination unit that determines the possibility of contact between the mobile device and the object based on the distance information of the object obtained by the distance information acquisition unit; Optical system.

10. The optical system according to claim 8 or 9 is mounted, Mobile device.

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