Optical device and moving device

Abstract

Provided are an optical device, etc., capable of maintaining or improving the detection accuracy of an object even when there is misalignment between a light-emitting element group and a light-receiving element group. A second specified number N2 of secondary light-emitting element groups, which is the number of light receiving elements S constituting a light receiving sensor 21, is defined. The "secondary light-emitting element group" is the result of expanding a primary light-emitting element group to further include at least some of the light emitting elements adjacent to the primary light-emitting element group. The "primary light-emitting element group" is composed of a plurality of light emitting elements L, which are a part of a first specified number N1 of light emitting elements L constituting a light source 11. One secondary light-emitting element group is switched from a light emission stopped state to a light-emitting state, and in response thereto, one light receiving element S corresponding to the one secondary light-emitting element group is switched from a non-sensing state to a sensing state.

Description

Optical and moving devices

[0001] The present invention relates to optical devices such as LiDAR (Light Detection and Ranging) systems.

[0002] An optical device has been proposed that is part of a LiDAR system mounted on a vehicle and detects targets (objects) in front of the vehicle, such as pedestrians, preceding vehicles, and oncoming vehicles, and that aims to simplify the configuration and suppress the generation of unnecessary light. Each light-receiving element that makes up the light-receiving unit corresponds to a light-emitting element group made up of multiple light-emitting elements that make up the light source, and light emitted from the multiple light-emitting elements that make up the light-emitting element group and reflected by the object is detected by the corresponding light-receiving element (see, for example, Patent Document 1).

[0003] Japanese Patent Application Laid-Open No. 2023-116125

[0004] However, since there is no overlap between the light emitting elements constituting adjacent light emitting element groups, if there is misalignment between the light emitting element group (light source) and the light receiving element group (light receiving sensor), the reflected light emitted from the light emitting element that does not correspond to the light receiving element will be detected by that light receiving element. This will result in a decrease in the detection accuracy of the target object, and therefore requires high alignment accuracy which will increase costs.

[0005] SUMMARY OF THE INVENTION It is therefore an object of the present invention to provide an optical device or the like that can maintain or improve the detection accuracy of an object even when there is misalignment between the light-emitting element group and the light-receiving element group.

[0006] The optical device of the present invention is an optical device comprising: a light-emitting unit having a first specified number of light-emitting elements that emit light toward an object; a light-receiving unit having a second specified number of light-receiving elements that receive the light reflected by the object; and a control device that switches between the light-emitting state and the light-emitting stop state of each of the first specified number of light-emitting elements, and switches between the sensing state and the non-sensing state of each of the second specified number of light-receiving elements, wherein each of the second specified number of light-emitting element groups, which are composed of a plurality of light-emitting elements that are part of the first specified number of light-emitting elements, corresponds to each of the second specified number of light-receiving elements, and some of the light-emitting elements of the first specified number are included in each of the different light-emitting element groups, and the control device is configured to switch between the sensing state of one light-receiving element of the second specified number of light-emitting elements that corresponds to that one light-emitting element group when switching one light-emitting element group of the second specified number of light-emitting element groups to the light-emitting state.

[0007] According to the optical device having this configuration, the detection accuracy of the object can be maintained or improved even if the light-emitting element group and the light-receiving element group are misaligned.

[0008] 1 is a diagram illustrating the configuration of an optical device according to one embodiment of the present invention; 2 is a diagram illustrating the configuration of a light-emitting element group; 3 is a diagram illustrating the configuration of a light-receiving element group; 4 is a diagram illustrating the correspondence between a light-emitting element group and a light-receiving element group; 5 is a diagram illustrating a first state switching mode of a light-emitting element group and a light-receiving element group; 6 is a diagram illustrating a second state switching mode of a light-emitting element group and a light-receiving element group; 7 is a diagram illustrating the configuration of a vehicle (mobile device) according to one embodiment of the present invention.

[0009] 1 as a first embodiment of the present invention is used as a detection device / image capture device that detects and captures an object OBJ by receiving light reflected from the object OBJ, as well as a distance measuring device that acquires distance information 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 reflected light from the object OBJ and the phase of the reflected light.

[0010] (Light Emitting Unit) The light emitting unit 10 includes a light source 11 and a light emitting optical system 12. The light source 11 is, for example, a vertical cavity surface emitting laser (VCSEL), and is configured with a first specified number N1 (N1 is plural) of light emitting elements L arranged two-dimensionally. For example, as shown in FIG. 2A, the light source 11 is configured with a first specified number N1 (N1 = n1 × m1) of light emitting elements L (L ij (i=1 to n1, j=1 to m1). Each light-emitting element L emits light in a direction perpendicular to each of the u1 direction and the v1 direction.

[0011] 2A illustrates a two-dimensional array of light-emitting elements L where n1 = 9 and m1 = 7, but n1 and m1 may each be changed to various numbers. One of n1 and m1 may be "1." The light-emitting elements L are, for example, configured with a semiconductor laser. The semiconductor laser emits, for example, infrared light (e.g., illumination light having a wavelength of 905 nm, which is included in the near-infrared range) that has little effect on the human eye.

[0012] The light-emitting optical system 12 is an optical system for irradiating the light emitted from the light source 11 toward the object OBJ. The light source 11 is disposed at the focal plane of the light-emitting optical system 12. The light-emitting optical system 12 irradiates the object OBJ with light emitted or projected from the light-emitting element L of the light source 11 as collimated light. Each of the light-emitting optical systems 12 is composed of a lens group made up of multiple lenses (e.g., 5 to 7 lenses). The light-emitting optical system 12 may include an aperture (a light-blocking member with an opening) that limits the illumination light to adjust the beam diameter (beam width). The shape of the aperture opening may be designed to be elliptical, rectangular, or other shape to match the shape of the illumination light.

[0013] (Light Receiving Unit) The light receiving unit 20 includes a light receiving sensor 21 and a light receiving optical system 22. The light receiving sensor 21 is configured with a second designated number N2 (N2 is a plural number smaller than N1) of light receiving elements S arranged two-dimensionally. For example, as shown in FIG. 2B, the light receiving sensor 21 is configured with a second designated number N2 (N2 = n2 × m2) of light receiving elements S (S ij (i = 1 to n2, j = 1 to m2).

[0014] 2B illustrates a two-dimensional array of light receiving elements S where n2 = 4 and m2 = 3, but n2 and m2 may each be changed to various numbers. One of n2 and m2 may be "1." The light receiving elements S are elements that receive reflected light from an object OBJ, perform photoelectric conversion, and output a signal. The light receiving elements S are configured with a PD (Photo Diode), APD (Avalanche Photo Diode), SPAD (Single Photo Avalanche Diode), etc.

[0015] The light-receiving optical system 22 is an optical system for causing the light-receiving sensor 21 to receive light reflected from the object OBJ. The light-receiving sensor 21 is disposed on the focal plane of the light-receiving optical system 22. The light-receiving optical system 22 focuses the light reflected from the object OBJ onto the light-receiving element S of the light-receiving sensor 21. Similar to the light-emitting optical system 12, the light-receiving optical system 22 is configured with a lens group made up of multiple lenses (e.g., 5 to 7 lenses). The light-receiving optical system 22 may have an optical filter member (band-pass filter) that passes only desired light and blocks (absorbs) other unnecessary light.

[0016] (Correspondence between light-emitting elements and light-receiving elements) Each of the second designated number N2 of light-receiving elements corresponds to the same number of second designated number N2 of primary light-emitting element groups. A "primary light-emitting element group" is composed of a plurality of light-emitting elements L that are part of the first designated number N1 of light-emitting elements L. For example, as shown in FIG. 3A, when there is no misalignment between the light source 11 and the light-receiving sensor 21, each light-receiving element Sij On the other hand, four light-emitting elements L arranged in a 2×2 type (n×m type) matrix (2i-1)(2j-1) , L (2i-1)2j , L 2i(2j-1) and L 2i2j The numbers n and m may be the same or different.

[0017] On the other hand, for example, as shown in FIGS. 3B and 3C, when there is misalignment between the light source 11 and the light receiving sensor 21, each light receiving element S ij The correspondence between the light receiving elements S and the "primary light emitting element group" has changed. ij corresponds to a light-emitting element L other than the plurality of light-emitting elements L constituting the "primary light-emitting element group." Therefore, as a result of the primary light-emitting element group being expanded to further include at least some of the light-emitting elements L adjacent thereto, each of the second designated number N2 of "secondary light-emitting element groups" is defined. For example, as shown in Figures 3B and 3C, ij On the other hand, nine light-emitting elements L are arranged in a 3×3 ((n+1)×(m+1)) matrix. (2i-1)(2j-1) , L (2i-1)2j , L (2i-1)(2j+1) , L 2i(2j-1) , L 2i2j , L 2i(2j+1) , L (2i+1)(2j-1) , L (2i+1)2j and L (2i+1)(2j+1) The "secondary light-emitting element group" shown in FIG. 11 (see left diagonal lines (left-leaning diagonal lines)) corresponding to the secondary light-emitting element group (see right diagonal lines (right-leaning diagonal lines)) and the light-receiving element S shown in FIG. 12 The secondary light-emitting element group (see right-hand diagonal lines) corresponding to the light-emitting element group (see left-hand diagonal lines) is composed of three light-emitting elements L 13 , L 23 and L 33The "secondary light-emitting element group" may be composed of a plurality of light-emitting elements arranged in a matrix of (n+k1)×(m+1) type (k1=2, 3, ...), a plurality of light-emitting elements arranged in a matrix of (n+1)×(m+k2) type (k2=2, 3, ...), or a plurality of light-emitting elements arranged in a matrix of (n+k1)××(m+k2) type (k2=2, 3, ...).

[0018] (Control Device) The control device 100 is configured to control the operation of the onboard equipment of the vehicle V 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.

[0019] The control device 100 is configured to switch between an emission state and an emission stop state of each light-emitting element L. The control device 100 switches between a sensing state (a state in which a signal is output in response to received light) and a non-sensing state (a state in which a signal is not output even when light is received) of each light-receiving element S. The control device 100 is configured to drive the light-emitting unit 10 or each light-emitting element L at a specified drive voltage and / or a specified drive frequency, and to control the output of the light-emitting unit 10 (the amount of illumination light). The control device 100 may control the operation of the light-emitting unit 10 to pulse the illumination light or to generate signal light by modulating the intensity of the illumination light.

[0020] 1, 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.

[0021] 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 10 (light-emitting time) to when the light-receiving unit 20 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 20 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 10 and the phase of the signal output from the light-receiving unit 20 and multiply the phase difference by the speed of light to acquire the distance information of the object OBJ.

[0022] The contact determination unit 120 is configured to determine the likelihood of contact between the object OBJ and the vehicle V, based on distance information of the object OBJ, such as traffic participants such as other vehicles and pedestrians, 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 V and the object OBJ, the control device 100 may be configured to decelerate, stop, or change direction (steer) the vehicle V, or to output an alert to alert passengers of the vehicle V.

[0023] (Mobile Device) The optical device 1 having the above configuration is mounted on, for example, a vehicle V (four-wheeled automobile) which is a mobile device according to one embodiment of the present invention shown in Fig. 4. The mobile device may be a two-wheeled automobile or a robot with a mobile function (or an autonomous mobile function), in addition to the vehicle V. The vehicle V may be a vehicle driven by a person or an automatically driven vehicle.

[0024] The light-emitting unit 10 is housed inside the housing of the headlight HL of the vehicle V together with a headlight light source (a light source that irradiates the front with white visible light). The light-emitting unit 10 may be attached to a location on the vehicle body below the headlight HL. The light-receiving unit 20 is attached to the vehicle V or its body at a location below the headlight HL. The control device 100 is disposed in an appropriate location inside the vehicle V (such as the space below the floor of the cabin space).

[0025] (Object Detection Process) During object detection process, the control device 100 sequentially switches a plurality of (e.g., nine) light-emitting elements L constituting each of the secondary light-emitting element groups from a non-emission state to an emission state in a designated order and at a designated cycle. When one light-emitting element L that was in the non-emission state is switched to the emission state, another light-emitting element L that was in the emission state up until then is switched to the non-emission state.

[0026] The control device 100 switches the light receiving elements S corresponding to the secondary light emitting element group including the light emitting elements L in the light emitting state from the non-sensing state (inactive state) to the sensing state (active state). For example, the nine light emitting elements L shown in FIG. 11 , L 12 , L 13 , L 21 , L 22 , L 23 , L 31 , L 32 and L 33 In response to the switching of any of the light receiving elements S 11 Three of the nine light-emitting elements L shown in FIG. 3A are switched from a non-sensing state (inactive state) to a sensing state (active state). 31 , L 32 and L 33 In response to the switching of any of the light receiving elements S 11 In addition to the light receiving element S 12 On the other hand, six of the nine light-emitting elements L shown in FIG. 11 , L 12 , L 13 , L 21 , L 22 and L 23 In response to the switching of any of the light receiving elements S 12 is kept or switched to an inactive state.

[0027] When the light receiving element S in the sensing state receives the pulsed reflected light, a signal corresponding to the reflected light is transmitted to the control device 100. Based on the signal, the control device 100 can generate a distance image composed of pixels corresponding to each light emitting element L, with pixel values ​​representing the distance to the object OBJ.

[0028] (Another embodiment of the present invention) The control device 100 may execute a “first detection process” in which one of the second designated number N of primary light-emitting element groups is switched from a non-emission state to an emission state, and in response, one of the second designated number N of light-receiving elements S corresponding to that one primary light-emitting element group is switched from a non-sensing state to a sensing state. A “first detection result” is acquired, which is the light detection result by the light-receiving unit 20 at this time (e.g., the time from emitting illumination light to the object OBJ to receiving reflected light from the object OBJ, the phase of the reflected light from the object OBJ, and distance information based thereon). Furthermore, as in the above embodiment, the control device 100 executes a “second detection process” in which one of the second designated number N of secondary light-emitting element groups is switched from a non-emission state to an emission state, and in response, one of the second designated number N of light-receiving elements S corresponding to that one secondary light-emitting element group is switched from a non-sensing state to a sensing state. At this time, a "second detection result" is obtained, which is the result of light detection by the light receiving unit 20. Then, the control device 100 may compare the first detection result with the second detection result.

[0029] If the difference between the first detection result and the second detection result (e.g., the sum of the deviations of the pixel values ​​of each pixel in the distance image) is equal to or greater than a reference level (e.g., a reference value or a threshold value), the control device 100 may thereafter prioritize the second detection process over the first detection process. If the difference between the first detection result and the second detection result is less than the reference level, the control device 100 may thereafter prioritize the first detection process over the second detection process.

[0030] 1. Optical system 10. Light emitting unit 11. Group of light emitting elements 12. Light emitting optical system 20. Light receiving unit 21. Light receiving sensor 22. Light receiving optical system 100. Control device 110. Distance information acquisition unit 120. Contact determination unit L. Light emitting element S. Light receiving element V. Vehicle (moving device) HL. Headlight OBJ. Object.

Claims

1. An optical device comprising: a light-emitting unit having a first specified number of light-emitting elements that emit light toward an object; a light-receiving unit having a second specified number of light-receiving elements that receive the light reflected by the object; and a control device that switches the light-emitting elements between an emission state and a non-emission state, and switches the light-receiving elements between a sensing state and a non-sensing state, wherein each of the second specified number of secondary light-emitting element groups is defined as a result of each of the second specified number of primary light-emitting element groups that are composed of a plurality of light-emitting elements that are part of the first specified number of light-emitting elements and that correspond to each of the second specified number of light-receiving elements being expanded to further include at least some of the adjacent light-emitting elements; and the control device is configured to switch one secondary light-emitting element group of the second specified number of secondary light-emitting element groups from an emission-non-sensing state to an emission state, and in response to this, switch one light-receiving element of the second specified number of light-receiving elements that corresponds to that one secondary light-emitting element group from a non-sensing state to a sensing state.

2. An optical device as defined in claim 1, wherein the control device compares a first detection result, which is the result of detection of light by the light receiving unit when a first detection process is executed in which one of the second specified number of primary light emitting element groups is switched from a light emitting stop state to a light emitting state, and one of the second specified number of light receiving elements corresponding to that one primary light emitting element group is switched from a non-sensing state to a sensing state, with a second detection result, which is the result of detection of light by the light receiving unit when a second detection process is executed in which one of the second specified number of secondary light emitting element groups is switched from a light emitting stop state to a light emitting state, and one of the second specified number of light receiving elements corresponding to that one secondary light emitting element group is switched from a non-sensing state to a sensing state, 3. An optical device according to claim 2, wherein the control device executes the second detection process with priority over the first detection process when the difference between the first detection result and the second detection result is equal to or greater than a reference level.

4. An optical device according to claim 3, wherein the control device executes the first detection process with priority over the second detection process when the difference between the first detection result and the second detection result is less than the reference level.

5. An optical device according to claim 1, wherein the primary light-emitting element group is composed of n×m light-emitting elements arranged in an n×m matrix, and the secondary light-emitting element group is composed of (n+1)×(m+1) light-emitting elements arranged in an (n+1)×(m+1) matrix, including the n×m light-emitting elements that make up the primary light-emitting element group.

6. An optical device according to claim 5, wherein n and m are equal.

7. The optical device according to claim 6, wherein n and m are 2.

8. An optical device according to claim 1, wherein the control device is provided with a distance information acquisition section that acquires distance information about the object based on the output of the light receiving section.

9. An optical device according to claim 8, wherein the control device is provided with a contact determination unit that determines the possibility of contact between the moving device and the object based on the distance information of the object obtained by the distance information acquisition unit.

10. A moving device equipped with the optical device according to claim 8 or 9.

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