Optical detection device and optical axis deviation determination method in optical detection device

Abstract

The present invention provides an optical detection device (10). The optical detection device (10) comprises: a light-emitting unit (30) having a plurality of light-emitting elements (32); a light-receiving unit (20) having a light-receiving element array (22), the light-receiving element array (22) being formed by a plurality of light-receiving pixels that receive reflected light corresponding to the irradiated light of the light-emitting unit (30); a storage unit that stores a reference light-receiving area in the light-receiving element array (22) corresponding to a generation position of a light intensity spot included in the irradiated light of the light-emitting unit (30); and a determination unit (100) that determines an optical axis offset using a positional offset between the reference light-receiving area and a detection light-receiving area of the light intensity spot included in the reflected light of the irradiated light in the light-receiving element array (22).

Description

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application claims priority based on Japanese Patent Application No. 2020-29960 filed on February 26, 2020, and Japanese Patent Application No. 2021-19781 filed on February 10, 2021, the disclosures of which are incorporated herein by reference in their entirety. Technical Field

[0003] The present disclosure relates to a technology for determining optical axis deviation in an optical detection device. Background Art

[0004] There is known a technique for detecting optical axis deviation in a distance measuring device that detects an object or distance in front of it by scanning laser light (for example, Japanese Patent Application Laid-Open No. 2007-248056).

[0005] However, conventional techniques require a preceding vehicle as an external reference object to detect optical axis deviation. Furthermore, if optical axis deviation is detected due to a decrease in the intensity of the output signal from the distance measuring device, it takes time to detect the deviation.

[0006] Therefore, an optical detection device is required to quickly determine the optical axis deviation in the optical detection device by itself. Summary of the Invention

[0007] The present disclosure can be implemented in the following forms.

[0008] A first embodiment provides an optical detection device. The optical detection device of the first embodiment comprises: a light-emitting unit having a plurality of light-emitting elements; a light-receiving unit having a light-receiving element array formed of a plurality of light-receiving pixels that receive reflected light corresponding to light irradiated by the light-emitting unit; a storage unit that stores a reference light-receiving area in the light-receiving element array corresponding to a location where a light intensity spot included in light irradiated by the light-emitting unit is generated; and a determination unit that determines optical axis offset using an offset between the reference light-receiving area and a detection light-receiving area in the light-receiving element array of the light intensity spot included in light irradiated by the light-emitting unit.

[0009] According to the optical detection device of the first aspect, the optical detection device can quickly determine the optical axis deviation in the optical detection device by itself.

[0010] A second aspect provides a method for determining optical axis misalignment in an optical detection device. The second aspect of the method involves obtaining a detection light-receiving area of a light intensity spot included in reflected light of the irradiated light in a light-receiving element array by a light-receiving unit. The light-receiving unit includes the light-receiving element array, which is formed of a plurality of light-receiving pixels that receive reflected light corresponding to irradiated light from a light-emitting unit having a plurality of light-emitting elements. A reference light-receiving area in the light-receiving element array, which is prepared in advance and corresponds to a location where the light intensity spot included in the irradiated light is generated, is obtained. The optical axis misalignment is determined using the misalignment between the reference light-receiving area and the detection light-receiving area.

[0011] The second embodiment of the optical axis offset determination method in an optical detection device allows the optical detection device to quickly determine optical axis offset in the optical detection device. Furthermore, the present disclosure can also be implemented as an optical axis offset determination program for an optical detection device or a computer-readable recording medium storing the program. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] The above-mentioned object and other objects, features and advantages of the present disclosure will become more apparent from the following detailed description with reference to the accompanying drawings.

[0013] Figure 1 It is an explanatory diagram showing an example of a vehicle equipped with the optical detection device according to the first embodiment.

[0014] Figure 2 This is an explanatory diagram showing a schematic configuration of an optical detection device used in the first embodiment.

[0015] Figure 3 This is an explanatory diagram schematically showing a light receiving element array used in the first embodiment.

[0016] Figure 4 This is an explanatory diagram showing the relationship between a light-emitting element, a light-receiving pixel, and light-emitting intensity in a conventional example.

[0017] Figure 5 This is an explanatory diagram showing the relationship between a light-emitting element, a light-receiving pixel, and light-emitting intensity in a conventional example.

[0018] Figure 6 This is an explanatory diagram showing the relationship between the light-emitting element, the light-receiving pixel, and the light-emitting intensity in the optical detection device according to the first embodiment.

[0019] Figure 7 This is a block diagram showing the functional configuration of the optical detection device according to the first embodiment.

[0020] Figure 8This is a flowchart showing the flow of optical axis deviation determination processing executed by the optical detection device according to the first embodiment.

[0021] Figure 9 This is an explanatory diagram showing the relationship between the light-emitting element, light-receiving pixels, and light-emitting intensity in the optical detection device according to the second embodiment.

[0022] Figure 10 This is an explanatory diagram showing an example of rotational optical axis deviation in the optical detection device according to the second embodiment.

[0023] Figure 11 This is a flowchart showing the flow of an optical axis deviation determination process executed by the optical detection device according to the second embodiment.

[0024] Figure 12 This is an explanatory diagram showing an example of changes in light-receiving pixels in the optical detection device according to the second embodiment. DETAILED DESCRIPTION

[0025] Hereinafter, the optical detection device and the optical axis deviation determination method in the optical detection device according to the present disclosure will be described based on several embodiments.

[0026] First embodiment:

[0027] like Figure 1 As shown, the optical detection device 10 in the vehicle of the first embodiment is mounted on, for example, a vehicle 50 for use. The optical detection device 10 includes a light detection and ranging (Lidar) 200 and a control device 100 that controls the operation of the Lidar 200. Furthermore, the optical detection device 10 is also referred to as a distance measuring device. In addition to being able to detect the distance to an object using the Lidar 200, it can also detect the position and characteristics of the object. Furthermore, the optical detection device 10 can also be used as a detection unit for a mobile object other than the vehicle 50, such as an unmanned aerial vehicle, a robot, or a fixed surveillance device.

[0028] like Figure 2As shown, the optical detection device 10 includes: an optical radar 200 as a light measuring unit that emits detection light by emitting light and receives incident detection reflected light, and a control device 100 that controls the light emitting and light receiving actions of the optical radar 200. The optical radar 200 and the control device 100 can be physically housed in an integrated housing, or can be housed in different housings. The optical radar 200 includes a light receiving unit 20, a light emitting unit 30, a motor 40, a rotation angle sensor 41, and a scanning mirror 42. When the scanning direction is the horizontal direction HD, the optical radar 200 has a predetermined scanning angle range SR in the horizontal direction HD. The light emitting unit 30 irradiates the detection light and the light receiving unit 20 receives the detection reflected light in units of a unit scanning angle SC obtained by dividing the scanning angle range SR into a plurality of angles, thereby acquiring detection reflection points throughout the entire scanning angle range SR to achieve ranging. The unit scanning angle SC specifies the resolution of the optical radar 200 in the horizontal direction HD or the resolution of the ranging result obtained by the optical radar 200. As the unit scanning angle becomes smaller, that is, as the number of detected reflection points increases, the resolution and the resolution increase. When the scanning angle range SR is scanned forward in one direction, or when the scanning angle range SR is scanned back and forth in two directions, the acquisition of detection points in the optical radar 200 in units of the unit scanning angle SC, that is, the light emitting processing and the light receiving processing are performed. The scanning angle range SR can be divided into a plurality of rows in the vertical direction VD according to the structure of the light receiving element in the light receiving unit 20 and the light receiving processing steps. Figure 2 In the example, the image is divided into four lines, L1 to L4. The optical inspection device 10 can use the vertical direction VD as the scanning direction. In this case, the vertical direction VD has a predetermined scanning angle range SR. The terms "horizontal" and "vertical" refer to the position of the optical inspection device 10 in its configured state, with the vertical direction referring to the vertical direction. This also applies to the vertical direction VD and horizontal direction HD described below.

[0029] The light receiving unit 20 includes a light receiving control unit 21, a light receiving element array 22, and a light receiving lens (not shown). It performs light receiving processing for outputting a detection signal representing a detection point based on the detection reflected light corresponding to the detection light irradiated from the light emitting unit 30. In addition, it performs light receiving processing for outputting background light image data based on the ambient light that is incident but does not correspond to the reflection from the light emitting unit 30. The ambient light includes ambient light of the surrounding environment brought by sunlight and illumination light that is not the detection light from the light emitting unit 30, and reflected light and scattered light from surrounding objects irradiated with sunlight and illumination light. Figure 3As shown, the photoreceiving element array 22 is a flat-plate photosensor with multiple photoreceiving elements 220 arranged in the vertical and horizontal directions, i.e., in the directions corresponding to the horizontal direction HD and the vertical direction VD of the scanning angle range SR. Each photoreceiving element is formed, for example, by a SPAD (Single Photon Avalanche Diode) or other photodiode. The term "photoreceiving pixel 230" is sometimes used as the minimum unit of light reception processing, i.e., the light receiving unit corresponding to the detection point. A photoreceiving unit refers to a photoreceiving pixel 231 composed of a single photoreceiving element, or to any of photoreceiving pixels 232 or 233 composed of multiple photoreceiving elements. In this embodiment, a photoreceiving element array 22 is used that includes a single photoreceiving element 230 in the vertical direction VD, for example, a photoreceiving pixel 231 arranged in a 1×1 vertical × horizontal pattern or a photoreceiving pixel 232 arranged in a 1×2 vertical × horizontal pattern. In the light-receiving element array 22, as the number of light-receiving elements constituting light-receiving pixels, or light-receiving units, decreases, the number of light-receiving units, or detection points, increases. In this embodiment, the light-receiving element array 22 includes, from the uppermost position in the vertical direction VD, light-receiving pixel rows RL1, RL2, RL3, and RL4, corresponding to four rows L1, L2, L3, and L4 of the scanning angle range SR, each consisting of a plurality of light-receiving pixels 230. Specifically, in this embodiment, among the plurality of light-receiving elements 220 included in the light-receiving element array 22, the plurality of light-receiving pixel groups 230 corresponding to the light-receiving pixel rows RL1, RL2, RL3, and RL4 are used for light reception processing.

[0030] Based on the emission of detection light by the light emitting unit 30, the light receiving control unit 21 performs light receiving processing to output an incident light intensity signal corresponding to the amount or intensity of incident light, using the light receiving pixels 230 corresponding to the light receiving pixel rows RL1 to RL4, per unit scanning angle SC, i.e., per column corresponding to the unit scanning angle SC. Specifically, the light receiving control unit 21 uses all light receiving pixels 230 to extract the current generated by the light receiving elements constituting the light receiving pixels 230 in response to the amount of incident light, or the voltage converted from the current, for each unit scanning angle SC, and outputs this signal to the control device 100 as the incident light intensity signal. Alternatively, when the light emitting unit 30 emits light corresponding to each row within the scanning angle range SR, the light receiving pixel 230 corresponding to the emission row is selected and output as the incident light intensity signal to the control device 100. The incident light intensity signal can be output to the control device 100 for each unit scanning angle SC, or the incident light intensity signal corresponding to the scanning angle range SR can be output to the control device 100 when scanning across the scanning angle range SR is completed. Alternatively, it can be said that the incident light intensity signal corresponding to the total number of photons received by the light-receiving elements constituting each light-receiving pixel 230 is output to the control device 100. Generally speaking, in a SPAD, since the amount of incident light received by a single light-receiving element 220 is small, the incident intensity signals from the eight light-receiving elements 220 are added together for each light-receiving pixel row RL1 to RL4, as in the case of light-receiving pixel 230, by an adder (not shown) to improve the signal-to-noise ratio. The distance measurement function unit that performs distance measurement based on detection points such as TOF (Time of Flight) can be provided as an integral circuit of the light-receiving control unit 21, or, as described later, can be provided as a program executed in the control device 100.

[0031] The light emitting unit 30 includes a light emitting control unit 31, a light emitting element 32, and a collimating lens, and irradiates the detection light once or discretely multiple times in units of a unit scanning angle SC. The light emitting element 32 is, for example, one or more infrared laser diodes, which emit infrared laser light as the detection light. The light emitting unit 30 may have a single light emitting element or a plurality of light emitting elements in the vertical direction. In the case of having a plurality of light emitting elements, the light emitting element that emits light can be switched according to the scanning timing by the light emitting control unit 31. The light emitting control unit 31 drives the light emitting element by a driving signal of a pulse driving waveform according to a light emitting control signal for instructing the light emitting element to emit light input from the control device 100 at each unit scanning angle, thereby emitting infrared laser light. The infrared laser irradiated from the light emitting unit 30 is reflected by the scanning mirror 42 and emitted toward the outside of the optical radar 200, that is, the range of the object to be detected.

[0032] use Figures 4 to 6, the relationship between the irradiated light emitted by the light emitting portion, the reflected light corresponding to the irradiated light, and the light receiving position of the reflected light in the light receiving element array is described. Figure 4 and Figure 5 Showing existing examples, Figure 6 In addition, the light emitting portion is the same as that in the conventional example and the example of the present embodiment, so the reference numerals in the present embodiment are used for explanation. The light emitting portion 30 includes a plurality of light emitting elements 32 in the vertical direction VD, for example, Figures 4 to 6 As shown, four light emitting elements 32 are arranged. Figure 6 Extract Figure 3 The light receiving pixels 230 for light receiving processing in the light receiving element array 22 shown are described. The irradiation light emitted from each light emitting element 32 is synthesized by the collimating lens PL and irradiated toward the outside of the optical detection device 10. The luminous intensity of the synthesized irradiation light is as follows. When the irradiation areas of two adjacent light emitting elements 32 overlap, the luminous intensity in the overlapping area LP is higher than the luminous intensity in other irradiation areas that do not overlap. On the other hand, when the irradiation areas of two adjacent light emitting elements 32 do not overlap, that is, when a non-irradiation area Sp is formed, the luminous intensity in the non-irradiation area Sp is lower than the luminous intensity in the irradiation area. The difference in these intensities, that is, the existence of the overlapping area LP and the non-irradiation area Sp, forms a light intensity spot. The light receiving element array 60 in the conventional example has, for example, four light receiving pixels 61 according to the arrangement direction of the light emitting elements 32, and each light receiving pixel 61 is arranged so as not to overlap with the overlapping area LP or the non-irradiation area Sp, that is, to set a gap 62 in a manner to avoid the overlapping area LP or the non-irradiation area Sp. Conventionally, this configuration has been able to suppress variations in the light receiving signal caused by uneven light intensity and to suppress a decrease in distance measurement accuracy caused by the variations in the light receiving signal.

[0033] In contrast, in the example of the present embodiment, the light-receiving element array 22 includes a plurality of light-receiving pixels 230, and the plurality of light-receiving pixels 230 are arranged without gaps according to the arrangement direction of the light-emitting elements 32, that is, they receive reflected light corresponding to the overlapping area LP or the non-irradiated area Sp. More specifically, the light-receiving element array 22 in the present embodiment has the following structure: a plurality of light-receiving pixels 230 are arranged in each light-receiving position corresponding to each overlapping area LP included in the irradiated area of the light-emitting element 32, that is, the light-receiving areas LA1, LA2, and LA3. The light-receiving positions corresponding to the overlapping area LP, that is, the light-receiving areas LA1 to LA3, include a plurality of light-receiving pixels 230. For example, each light-receiving area LA1 to LA3 can be formed by a plurality of light-receiving pixels 230 provided on one side of the adjacent light-receiving pixel columns, or each light-receiving area LA1 to LA3 can be formed by one or more light-receiving pixels 230 provided on both sides of the adjacent light-receiving pixel rows RL1 / RL2, RL2 / RL3, and RL3 / RL4. In Figure 6 In the example, each light-receiving pixel 230 includes one light-receiving element 220 in the direction perpendicular to the arrangement direction of the light-emitting elements 32. As a result, the dimension of each light-receiving pixel 230 in the vertical direction VD is equal to the height of one light-receiving pixel 220. Alternatively, by configuring multiple light-receiving pixels 230 in the light-receiving areas LA1, LA2, and LA3, a light-receiving pixel 230 can be provided with two or more light-receiving elements 220 in the direction perpendicular to the arrangement direction of the light-emitting elements 32. In other words, the light-receiving pixels 230 only need to be sized to allow the overlapping area LP, which causes the intensity unevenness of the reflected light, to be received by the multiple light-receiving pixels 230. The dimension of the light-receiving pixel 230, i.e., the length in the vertical direction VD, is, for example, several tens of μm. In contrast, the same length of conventional light-receiving elements is, for example, several hundred μm, an order of magnitude greater. Similarly, a corresponding relationship can be established between the multiple light-receiving pixels 230 in the non-irradiated area Sp.

[0034] The motor 40 is equipped with a motor driver (not shown). A rotation angle sensor 41 is provided within the motor 40 to detect the rotation angle of the motor 40. The motor driver receives a rotation angle signal from the rotation angle sensor 41 and a rotation angle instruction signal from the control device 100, changing the voltage applied to the motor 40 to control the rotation angle of the motor 40. The motor 40 may be, for example, an ultrasonic motor, a brushless motor, or a brush motor, and includes a known mechanism for reciprocating within a scanning angle range SR. A scanning mirror 42 is mounted on the front end of the output shaft of the motor 40. The scanning mirror 42 is a reflector, or mirror, that scans the detection light emitted from the light-emitting element 32 in the horizontal direction HD. By being reciprocally driven by the motor 40, scanning of the scanning angle range SR in the horizontal direction HD is achieved. A single reciprocating scan of the scanning mirror 42 is called a frame and is the detection unit of the optical radar 200. Furthermore, the emission of detection light by the light-emitting unit 30 is performed in response to the forward or reciprocating displacement of the scanning mirror 42. That is, object detection by the optical radar 200 can be performed only in one direction or two directions within the scanning angle range SR. The scanning mirror 42 realizes scanning of detection light and reception of reflected light within a scanning angle range such as 120 degrees or 180 degrees. Scanning in the vertical direction VD can also be performed instead of the horizontal direction HD. In addition, in addition to the horizontal direction HD, scanning in the vertical direction VD, that is, changing the scanning position in the vertical direction VD can also be achieved. In order to achieve scanning in the horizontal direction HD and the vertical direction VD, the scanning mirror 42 can be a multifaceted mirror, such as a multifaceted mirror, or can also be a single-sided mirror with a mechanism for swinging in the vertical direction VD, or other single-sided mirrors that swing in the vertical direction VD. In addition, the scanning mirror 42 can also be driven by the motor 40 to perform rotational scanning. In this case, the light emitting / receiving processing performed by the light emitting unit 30 and the light receiving unit 20 can be performed corresponding to the scanning angle range SR. Furthermore, for example, in the case of realizing a scanning angle range SR of about 60 degrees, the scanning mirror 42 may not be provided, but an array of light-receiving elements having a lateral width corresponding to the scanning angle range SR may be provided, and object detection, i.e., ranging processing, may be performed by sequentially selecting rows and columns.

[0035] The detection light emitted from the light emitting unit 30 is reflected by the scanning mirror 42 and scanned within the horizontal scanning angle range SR in units of the unit scanning angle SC. The detection light reflected by the target object is reflected by the scanning mirror 42 to the light receiving unit 20 and enters the light receiving unit 20 at each unit scanning angle SC. The light receiving unit 20 performs light receiving processing in units of columns according to the light emission timing of the light emitting unit 30. The unit scanning angle SC for which the light receiving processing is performed increases sequentially, and as a result, scanning for light receiving processing can be performed to cover the desired scanning angle range SR. The light emitting unit 30 and the light receiving unit 20 can be rotated together with the scanning mirror 42 by the motor 40, or can be separated from the scanning mirror 42 and rotated without the motor 40. In addition, the following structure can also be provided: instead of the scanning mirror 42, a plurality of light receiving pixels or a light receiving element array 22 arranged in an array corresponding to the scanning angle range SR are provided, and the laser is directly irradiated to the outside world in sequence, and the light receiving pixels are switched in sequence to directly receive the reflected light.

[0036] like Figure 7 As shown, the control device 100 includes a central processing unit (CPU) 101 as a computing unit, a memory 102 as a storage unit, an input / output interface 103 as an input / output unit, and a clock generator (not shown). The CPU 101, memory 102, input / output interface 103, and clock generator are connected for bidirectional communication via an internal bus 104. The memory 102 includes a nonvolatile, read-only storage unit for storing an optical axis deviation determination program Pr1 for executing the optical axis deviation determination process, such as a ROM, and a readable and writable memory by the CPU 101, such as a RAM. The nonvolatile, read-only area of the memory 102 includes a reference light receiving area storage area 102a, which stores a reference light receiving area RP serving as a reference for determining optical axis deviation, and an optical axis deviation prediction period storage area 102b, which stores a predicted period for optical axis deviation. Furthermore, the nonvolatile, read-only area can be rewritten when updating the program or the reference value. The CPU 101, i.e., the control device 100, functions as a determination unit by developing and executing the optical axis deviation determination program Pr1 stored in the readable and writable memory 102. The CPU 101 may be a single CPU, multiple CPUs each executing a program, or a multitasking or multithreading CPU capable of executing multiple programs simultaneously.

[0037] The input / output interface 103 is connected to the light receiving control unit 21 constituting the light receiving unit 20, the light emission control unit 31 constituting the light emitting unit 30, the motor 40, and the rotation angle sensor 41 via control signal lines. A light emission control signal is sent to the light emission control unit 31, and a light reception control signal instructing light reception processing for object detection is sent to the light receiving control unit 21. An incident light intensity signal indicating the intensity of detected reflected light is received from the light reception control unit 21. A rotation angle instruction signal is sent to the motor 40, and a rotation angle signal is received from the rotation angle sensor 41.

[0038] The optical axis shift determination process executed by the optical detection device 10 according to the first embodiment will be described. Figure 8 The processing routine shown can be executed every time a predetermined period, such as 10 days, 30 days, or 2 months, has passed during the operation of the optical detection device 10. In addition, when the optical detection device 10 is mounted on a vehicle 50 for use, it can also be executed every time the vehicle control system is started, or every time the start switch is turned on, or every time the cumulative driving time of the vehicle 50 has passed a predetermined time, or every time the cumulative driving distance of the vehicle 50 has exceeded a predetermined distance. In addition, it can also be executed at a fixed time after the vehicle 50 has been inspected or repaired. The CPU 101 executes the optical axis deviation determination program Pr1 to execute. Figure 8 The processing flow shown.

[0039] The CPU 101 obtains the detection reflected light from the light receiving unit 20 via the input / output interface 103 (step S100). The detection reflected light is the incident light that is incident on the light receiving unit 20 after being reflected from the object by the irradiation light irradiated by the light emitting unit 30 as the detection light. The reflected light received by the light receiving unit 20, more specifically, by the light receiving element array 22, includes Figure 6The light emitted by the light-emitting unit 30 shown includes a light intensity spot corresponding to the overlapping area LP or the non-irradiated area Sp. The incident light intensity output from the light-receiving pixel 230 receiving the reflected light corresponding to the overlapping area LP is higher than the incident light intensity output from the light-receiving pixel 230 receiving the reflected light corresponding to the normal area other than the overlapping area LP and the non-irradiated area Sp. On the other hand, the incident light intensity output from the light-receiving pixel 230 receiving the reflected light corresponding to the non-irradiated area Sp is lower than the incident light intensity output from the light-receiving pixel 230 receiving the reflected light corresponding to the normal area. Therefore, the incident light intensity can be used to determine whether the light-receiving pixel 230 receives the light intensity spot. For example, a light-receiving pixel 230 whose difference from the incident light intensity output from the light-receiving pixel 230 receiving the reflected light corresponding to the normal area is greater than a predetermined determination difference can be determined as a light-receiving pixel 230 receiving the light intensity spot. By pre-assigning position numbers to the light-receiving pixels 230, the position of the light-receiving pixel 230 receiving the light intensity spot can be easily determined. Alternatively, the judgment difference may be sequentially updated, i.e., learned, using statistical values, such as the average and median, of incident light intensity of reflected light corresponding to a normal area, and statistical values, such as the average and median, of incident light intensity corresponding to a light intensity spot, obtained during use of the optical detection device 10. In this case, a judgment difference that reflects the influence of the environment in which the optical detection device 10 is actually used can be used, thereby improving the judgment accuracy of the light-receiving pixels 230 that receive the light intensity spot.

[0040] The CPU 101 obtains a pre-prepared reference light-receiving area from the reference light-receiving area storage area 102a of the memory 102 (step S102). The reference light-receiving area is a light-receiving position in the light-receiving element array 22 corresponding to the location where the light intensity spot contained in the irradiated light from the light-emitting unit 30 is generated. When the optical detection device 10 is set in the correct position, for example, when it is mounted on the vehicle 50, it is the position of the light-receiving pixel 230 that receives the reflected light corresponding to the overlapping area LP or the non-irradiated area Sp. The position of the light-receiving pixel 230 that receives the reflected light corresponding to the overlapping area LP or the non-irradiated area Sp is obtained in advance at the timing of setting the optical detection device 10 and stored as a position number in the reference light-receiving area storage area 102a. In addition, in the first embodiment, the reference light-receiving area is also referred to as the reference light-receiving position.

[0041] The CPU 101 determines whether the position of the received light intensity spot obtained from the light receiving unit 20, that is, the detected light receiving area of the overlapping area LP or the non-irradiated area Sp, that is, the actual light receiving position is consistent with the reference light receiving position obtained from the memory 102 (step S104). Specifically, the CPU 101 determines whether the position number of the light receiving pixel 230 corresponding to the actual light receiving position is consistent with the position number of the reference light receiving position. If the CPU 101 determines that the actual light receiving position is consistent with the reference light receiving position (step S104: yes), it is determined that no optical axis offset has occurred and the present processing routine is terminated. This is because when the actual light receiving position is consistent with the reference light receiving position, no optical axis offset has occurred in the optical detection device 10. In addition, since the light intensity spot can be detected by a plurality of light receiving pixels 230, for example, a small position number or an intermediate position number in the actual light receiving position can be compared with the position number of the corresponding reference light receiving position, or all position numbers of the actual light receiving position can be compared with the position numbers of all reference light receiving positions.

[0042] If the CPU 101 determines that the actual light receiving position and the reference light receiving position do not match (step S104: No), it obtains the position offset Dp (step S106). The position offset Dp is, for example, the difference between the position number RN of the actual light receiving position and the position number SN of the reference light receiving position. Alternatively, the physical distance from one end of the light receiving element array 22 to the center or reference point of each light receiving pixel 230 may be pre-associated, and the difference between the distance between the actual light receiving position and the distance between the reference light receiving position may be calculated. The CPU 101 determines whether the position offset Dp is less than the allowable offset Dra (step S108). If the position offset Dp is less than the allowable offset Dra (step S108: Yes), it predicts the time when the optical axis offset will occur (step S112), and ends this processing routine. The allowable offset Dra is a value smaller than the non-allowable offset Drc used to determine whether the optical axis offset has occurred. For example, it is set based on statistical data to indicate that the optical axis offset may occur within six months. The prediction of the time when optical axis shift will occur is achieved by using the position information of the actual light-receiving position during the execution of this processing routine to calculate the position shift amount per unit time of the actual light-receiving position or per unit number of executions of this processing routine. The position shift amount that will occur over time is then calculated as the predicted position shift amount, and the time when the predicted position shift amount exceeds the allowable shift amount Dra is calculated. The calculated predicted time when optical axis shift will occur is stored in the predicted optical axis shift period storage area 102b of the memory 102. In addition to storage in the predicted optical axis shift period storage area 102b, notification processing can also be performed to the user of the optical inspection device 10 at a time corresponding to the predicted optical axis shift period, for example, one month or two weeks later. If the optical inspection device 10 is installed in the vehicle 50, a notification urging inspection can be provided via the information display device of the vehicle 50. Furthermore, the predicted time when optical axis shift will occur stored in the predicted optical axis shift period storage area 102b is used as diagnostic information for the optical inspection device 10 and can also be used by maintenance personnel for confirmation and maintenance during regular inspections. Furthermore, the use status of the vehicle 50 , specifically, the monthly travel distance or the weekly travel distance, may be used to notify the user of the travel distance at which the optical axis shift may occur.

[0043] If it is determined that the positional offset Dp is not less than the permissible offset Dra, that is, the positional offset Dp is greater than the permissible offset Dra (step S108: No), CPU 101 determines whether the positional offset Dp is less than the non-permissible offset Drc (step S110). If it is determined that the positional offset Dp is less than the non-permissible offset Drc (step S110: Yes), CPU 101 proceeds to step S112. In this case, since unacceptable optical axis offset has not yet occurred, preventive processing is performed. If it is determined that the positional offset Dp is not less than the non-permissible offset Drc, that is, the positional offset Dp is greater than the non-permissible offset Drc (step S110: No), CPU 101 notifies the user that an optical axis offset has occurred (step S114) and terminates this processing routine. If the positional offset Dp is greater than the non-permissible offset Drc, unacceptable optical axis offset has occurred in the optical detection device 10. The unacceptable offset Drc corresponds to the positional offset of the actual light-receiving position corresponding to an unacceptable optical axis offset. For example, the unacceptable optical axis offset corresponds to an optical axis offset that may reduce the distance measurement accuracy of the optical detection device 10 below a predetermined accuracy. For example, the predetermined accuracy is a pre-assumed error rate, such as ±5%. Notification of the optical axis offset is performed to the user of the optical detection device 10. If the optical detection device 10 is installed in a vehicle 50, notification can be provided via an information display device or voice prompting prompt inspection. Furthermore, the unacceptable offset Drc is a first determination value, and the acceptable offset Dra is a second determination value, which is smaller than the first determination value.

[0044] According to the optical detection device 10 of the first embodiment described above, since the optical axis offset is determined by using the actual light receiving position of the light intensity spot detected by the light receiving unit 20 having the light receiving element array 22 formed by a plurality of light receiving pixels 230 and the reference light receiving position in the light receiving element array 22 corresponding to the generation position of the light intensity spot contained in the irradiated light of the light emitting unit 30, the optical detection device 10 can determine the optical axis offset early as a single unit. In addition, the accuracy of determining the optical axis offset can be improved. Specifically, by using a plurality of light receiving pixels 230, the detection accuracy of the actual light receiving position of the light intensity spot in units of light receiving pixels 230 is improved, and the accuracy of determining the offset amount relative to the reference light receiving position is improved. As a result, in the past, the optical axis offset could be detected before an undetectable and unacceptable optical axis offset occurred, and the ranging accuracy of the optical detection device 10 could be maintained or the reduction in accuracy could be suppressed. In contrast, as Figure 4 and Figure 5As shown, conventional optical detection devices have light-receiving pixels 61 arranged so as not to detect the light intensity spot, or because the light-receiving pixels 61 are too large, they are unable to determine the light-receiving position of the light intensity spot. Consequently, optical axis misalignment is determined only after observing the signal intensity of the detection signal output from the light-receiving unit for a long period of time and observing a decrease in signal intensity. This determination of optical axis misalignment takes time, and the greater the reduction in ranging accuracy at the time optical axis misalignment is determined, the greater the optical axis misalignment.

[0045] Furthermore, the plurality of light-receiving pixels 230 are arranged without gaps in the arrangement direction of the light-emitting elements 32, so that the light intensity spot included in the reflected light is received by the plurality of light-receiving pixels 230, or the size of each of the plurality of light-receiving pixels 230 is set so that the light intensity spot included in the reflected light is received by the plurality of light-receiving pixels 230. Therefore, the position of the light intensity spot can be determined with higher accuracy, and the accuracy of determining the optical axis offset can be improved.

[0046] In the above embodiment, the reference light receiving position is set when the optical detection device 10 is mounted on the vehicle 50. However, the reference light receiving position, i.e., the light receiving position of the light intensity spot in the light receiving element array 22 when no optical axis shift occurs, may be updated, i.e., learned, using initial detection results after the vehicle 50 begins traveling, for example, statistically processed values such as the average or median of the incident light intensity corresponding to the reflected light and the incident light intensity spot obtained during a 100 km to 500 km journey. In this case, a reference light receiving position can be set that reflects the actual driving state of the vehicle 50 and the installation environment of the optical detection device 10. For example, by setting a reference light receiving position that reflects the vibrations of the vehicle 50 during travel, it is possible to determine optical axis shift while eliminating or reducing interference caused by the movement of the vehicle 50.

[0047] Second embodiment:

[0048] The optical detection device in the vehicle of the second embodiment is described. The optical detection device in the vehicle of the second embodiment detects the optical axis offset in the horizontal direction, the optical axis offset in the rotational direction, and the relative optical axis offset between the lens and the light receiving element array 22, in addition to the optical axis offset in the vertical direction, and is different from the optical detection device 10 of the first embodiment. On the other hand, since the structure of the optical detection device of the second embodiment is the same as that of the optical detection device 10 of the first embodiment, the same figure marks are marked and the description is omitted. In addition, the optical axis offset determination program Pr1 is executed by CPU101 to achieve Figure 11The processing flow shown in FIG. Furthermore, in the second embodiment, the term "light-receiving area" includes not only the position of the light-receiving area but also its size / area. Therefore, the reference light-receiving area storage area 102 a of the memory 102 stores, in addition to the reference light-receiving position, the reference light-receiving area of the light-receiving area corresponding to the light intensity spot as reference light-receiving area information.

[0049] For explaining the optical axis deviation in the vertical direction VD Figure 6 In the embodiment, the structure of each light-receiving pixel 230 in the vertical direction VD is clearly described, and the detailed structure of each light-receiving pixel 230 in the horizontal direction is omitted. In contrast, in the second embodiment, the optical axis offset in the horizontal direction HD, the optical axis offset in the rotational direction, and the relative optical axis offset between the lens and the light-receiving element array 22 are also determined. Therefore, a plurality of light-receiving pixels 230 are arranged without gaps in a direction perpendicular to the arrangement direction of the light-emitting elements 32. Figure 9 The structure of each light-receiving pixel 230 in the horizontal direction is also clearly recorded, that is, Figure 6 Each light-receiving pixel 230 shown in FIG. 1 is configured to have a plurality of light-receiving pixels 230 in the horizontal direction. Figure 9 In the example of FIG. 1 , a light receiving element array 22 is used. The light receiving element array 22 includes light receiving pixels 230 each having one light receiving element in the vertical direction VD and the horizontal direction HD, that is, light receiving pixels 231 arranged in a 1×1 pattern. As described in the first embodiment, the light receiving pixels 230 used in the light receiving process are part of the plurality of light receiving pixels 230 in the light receiving element array 22 having a plurality of light receiving elements 220. Figure 9 In the embodiment, the light receiving process is performed by the light receiving pixels 230 constituting the four light receiving blocks RB1, RB2, RB3, and RB4. Figure 9 The light-receiving element array 22 is schematically shown. For example, the light-receiving element array 22 may include 596 vertically and 42 horizontally arranged light-receiving elements, or other row and column combinations. Furthermore, the light-receiving element array 22 may be configured to detect optical axis deviation in the vertical, horizontal, and rotational directions, that is, to include multiple light-receiving pixels 230 in the vertical direction VD and the horizontal direction HD. The light-receiving pixels 230 may include any number of light-receiving elements in a vertical and horizontal arrangement, such as 2×2, 1×2, or 2×1.

[0050] In this embodiment, for the sake of convenience, the light receiving areas LA11, LA21, and LA31 having a roughly circular shape are used as the light receiving areas of the light intensity spot for explanation. In addition, a roughly rectangular shape also includes an ellipse. In addition, the light receiving areas LA11, LA21, and LA31 may also have a roughly rectangular shape including a trapezoid, a parallelogram, and a polygon, or other shapes. In the case of a roughly circular shape, the center position of the circle can be considered to be the center of the light receiving area. In the case of a roughly rectangular shape, the center position can be considered to be the center of the light receiving area, that is, the position of the corresponding light receiving pixel 230. Figure 9 In the example, when the vertical direction VD is defined as the Y direction and the horizontal direction HD is defined as the X direction, the position of each light-receiving pixel 230 in the light-receiving element array 22 can be expressed by XY coordinates. Furthermore, the method for determining the light-receiving pixel 230 receiving the light intensity spot or the light-receiving position of the light-receiving pixel 230, that is, the light-receiving area, has been described in the first embodiment.

[0051] exist Figure 10 In the figure, the left-side light-receiving element array 22 indicated by symbol A schematically shows the light-receiving state when no optical axis offset occurs in any of the vertical / horizontal / rotational axis / optical axis directions, and the right-side light-receiving element array 22 indicated by symbol B schematically shows the light-receiving state when optical axis offset occurs in the rotational axis or blur occurs. Blur is an optical axis offset in the optical axis direction of the optical detection device 10, and is a type of optical axis offset caused by a shift in the relative distance between the optical system related to the focus, mainly a lens such as the collimating lens PL, and the light-receiving element array 22 in a direction parallel to the optical axis. Figure 10 Blur appears in the light-receiving areas LA11 and LA21. Blur appears in the light-receiving element array 22 as a change in the size, or area, of the light-receiving area. When the light-receiving area, which serves as a reference for no blur, increases, the relative distance between the collimating lens PL and the light-receiving element array 22 decreases. In the structure of the optical detection device 10, when the light-receiving area, which serves as a reference, decreases, the relative distance between the collimating lens PL and the light-receiving element array 22 increases. The increase or decrease in the relative distance between the collimating lens PL and the light-receiving element array 22 relative to the reference distance occurs based on at least one of a positional deviation of the collimating lens PL in a direction parallel to the optical axis and a positional deviation of the light-receiving element array 22.

[0052] exist Figure 10 In B, the light receiving area LA11 and the light receiving area LA21 are shifted in the horizontal direction (X direction) relative to the reference position (reference straight line BVL) shown in A, and their areas are increased. Figure 10The positions of the light receiving areas LA11 and LA21 shown in B can be obtained as coordinate positions with the upper left side of the light receiving element array 22 as the origin position (x, y) = (0, 0). That is, the center of gravity position obtained using the coordinate positions of the corresponding plurality of light receiving pixels 230, or the coordinate value corresponding to the center position, can be obtained as the coordinate position representing the position of each light receiving area LA11, LA21, LA31. The type of positional offset of each light receiving area LA11, LA21, LA31 and the amount of positional offset (the degree of positional offset) can be calculated by Figure 10 The detection straight line RVL of the center of each light receiving area LA11, LA21, LA31 shown in B is calculated by Figure 10 The straight line that is the center of each light receiving area LA11, LA21, and LA31, which serves as the reference, is taken as the reference straight line BVL, and the geometric positional relationship between the two straight lines is obtained. In addition, a linear equation representing the reference straight line BVL is predetermined, and the linear equation representing the detection straight line RVL can also be determined using the coordinate positions of the light receiving areas LA11 and LA31, or can be calculated using the three points of the light receiving areas LA11, LA21, and LA31 using a known linear approximation method such as the least squares method. Figure 10 In the example of B, the light receiving area LA21 is offset in the horizontal direction, and the detection line RVL is rotated by a rotation angle θ relative to the reference line BVL. The axial offset of the detection line RVL relative to the reference line BVL in the horizontal direction HD and the vertical direction VD can be calculated using the coordinate values of the midpoint of the reference line BVL and the midpoint of the detection line RVL. The rotation angle θ formed by the detection line RVL and the reference line BVL can be calculated using various well-known methods, such as a method using the inner product of two vectors.

[0053] Furthermore, the area of the light receiving area LA11 is larger than that of the light receiving area LA21. Figure 10Above the Y coordinate value, that is, in the direction where the Y coordinate value becomes 0, an optical axis offset occurs in the optical axis direction where the relative distance between the collimating lens PL and the light receiving element array 22 approaches. Regarding blurring, for example, the degree of blurring can be determined based on the relationship between the size of the predetermined area of the light receiving region and the relative distance between the collimating lens PL and the light receiving element array 22, or based on the relationship between the predetermined area of the light receiving region and the inclination of the detection line RVL relative to the surface of the light receiving element array 22. The size, that is, the area, of each light receiving area LA11, LA21, and LA31 can be obtained by multiplying the area of one predetermined light receiving pixel 230 by the number of light receiving pixels 230 constituting each light receiving area LA11, LA21, and LA31, or by approximately calculating the area of a circle with the maximum distance obtained from the coordinate positions of the light receiving pixels 230 constituting each light receiving area LA11, LA21, and LA31 as its diameter, or by approximately calculating the area of a rectangle with two orthogonal maximum distances as its sides. In the present embodiment, an accurate value of the area is not required, and comparison with a reference area determined by the same calculation method may be performed.

[0054] The optical axis shift determination process executed by the optical detection device 10 according to the second embodiment will be described. Figure 11 The processing routine shown can be executed each time a predetermined period, such as 10 days, 30 days, or 2 months, passes during the operation of the optical detection device 10. In addition, when the optical detection device 10 is mounted on a vehicle 50 for use, it can also be executed each time the vehicle's control system is started, or each time the start switch is turned on, or each time the cumulative driving time of the vehicle 50 passes a predetermined time, or each time the cumulative driving distance of the vehicle 50 exceeds a predetermined distance. In addition, it can also be executed at a predetermined time after the vehicle 50 is inspected or repaired. The CPU 101 executes the optical axis deviation determination program Pr1 to execute Figure 11 The same processing steps as those described in the first embodiment are denoted by the same step numbers and are only briefly described.

[0055] The CPU 101 obtains the detection reflected light from the light receiving unit 20 via the input / output interface 103 (step S100). The reflected light received by the light receiving unit 20, more specifically, the light receiving element array 22, includes Figure 9 The overlapping area LP or the overlapping area LP included in the irradiation light of the light emitting unit 30 shown in FIG. Figure 5The light receiving areas LA11, LA21, and LA31 corresponding to the non-irradiated areas Sp are shown. Whether the light receiving pixel 230 receives the light receiving areas LA11, LA21, and LA31 can be determined using the incident light intensity as described in the first embodiment. The CPU 101 obtains the reference light receiving position and reference light receiving area as pre-prepared reference light receiving area information from the reference light receiving area storage area 102a of the memory 102 (step S101). The reference light receiving position is the light receiving position in the light receiving element array 22 corresponding to the generation position of the light receiving areas LA11, LA21, and LA31 included in the irradiated light of the light emitting unit 30. When the optical detection device 10 is set in a correct posture, for example, when it is mounted on the vehicle 50, it is the position of the light receiving pixel 230 that receives the reflected light corresponding to the light intensity spot. More specifically, it is the coordinate position corresponding to the center or center of gravity of the light receiving areas LA11, LA21, and LA31. The reference light-receiving area is the area of light-receiving areas LA11, LA21, and LA31 in the light-receiving element array 22 corresponding to the location where the light intensity spot contained in the irradiated light from the light-emitting unit 30 is generated. When the optical system related to the focus of the optical detection device 10, primarily the lens and the light-receiving element array 22, are correctly positioned, the size of the light-receiving area is determined by the number of light-receiving pixels 230 corresponding to the light-receiving areas LA11, LA21, and LA31. The reference light-receiving position and reference light-receiving area are pre-acquired when the optical detection device 10 is installed and stored as coordinate positions (x, y) and area values in the reference light-receiving position storage area 102a.

[0056] CPU 101 obtains the offset Dps between the detection light-receiving area received from the light-receiving unit 20 and the reference light-receiving area received from the memory 102 (step S103). The offset Dps is an indicator of the optical axis offset. In this embodiment, it includes at least both positional offset and size / area offset. The positional offset can be obtained, for example, as the difference between the coordinate position corresponding to the center or center of gravity of the detection light-receiving area and the coordinate position of the reference light-receiving position. As described above, the positional offset in the horizontal direction HD and the vertical direction VD is obtained as the difference between the coordinate values of the midpoint of the detection line RVL and the reference line BVL in the X and Y directions, respectively. The rotational offset about the optical axis is obtained based on the inner or outer angle between the detection line RVL and the reference line BVL. Furthermore, in this embodiment, the optical axis offset includes the relative positional offset between the collimator lens PL and the light-receiving element array 22 in the optical axis direction, as described above. This relative positional offset occurs due to changes in the relative distance between the collimator lens PL and the light-receiving element array 22, and appears as a shift, or change, in the size of the detection light-receiving area. Therefore, the difference between the area of the reference light receiving area and the area of the detection light receiving area is calculated as an index representing the offset. In addition, each offset in this embodiment is not limited to a difference, but may also be a ratio of an actual light receiving value to a reference value.

[0057] CPU101 determines whether the offset Dps is within the same allowable range (step S105). Specifically, CPU101 determines whether the absolute value of the offset Dps is less than the predetermined same reference offset Drb, that is, whether |Dps|<Drb. The same reference offset Drb is equivalent to the position offset that can be determined to be the same or approximately the same in the first embodiment. If it is determined that the absolute value of the offset Dps is less than the same reference offset Drb (step S105: yes), CPU101 determines that no optical axis offset has occurred and ends this processing routine. This is because when the absolute value of the offset Dps between the detection light-receiving area and the reference light-receiving area is less than the same reference offset Drb, it can be considered that no optical axis offset has occurred or no optical axis offset has occurred in the optical detection device 10.

[0058] If the absolute value of the offset Dps is determined to be not less than the same reference offset Drb, that is, |Dps| ≥ Drb (step S105: No), CPU 101 then determines whether the absolute value of the offset Dps is less than the first reference offset Dr1, that is, whether |Dps| < Dr1 (step S107). If the offset Dps is determined to be less than the first reference offset Dr1 (step S107: Yes), CPU 101 predicts the time when optical axis offset will occur (step S112), terminating this processing routine. The first reference offset Dr1 is a value greater than the same reference offset Drb and less than the second reference offset Dr2 used to determine the occurrence of optical axis offset. For example, it is set based on statistical data to indicate that optical axis offset may occur within six months.

[0059] If the absolute value of the offset Dps is determined to be not less than the first reference offset Dr1, that is, |Dps| ≥ Dr1 (step S107: No), CPU 101 determines whether the absolute value of the offset Dps is less than the second reference offset Dr2, that is, whether |Dps| < Dr2 (step S109). If the offset Dps is determined to be less than the second reference offset Dr2 (step S109: Yes), CPU 101 proceeds to step S112. In this case, since unacceptable optical axis deviation has not occurred, preventive processing is performed. If the absolute value of the offset Dps is determined to be not less than the second reference offset Dr2, that is, |Dps| ≥ Dr2 (step S109: No), CPU 101 notifies the user of the occurrence of optical axis deviation (step S114) and terminates this processing routine. If the positional offset Dp is greater than or equal to the unacceptable offset Drc, unacceptable optical axis deviation has occurred in the optical detection device 10. The second reference offset Dr2 corresponds to the positional offset of the detection light-receiving area corresponding to an unacceptable optical axis offset. For example, this offset corresponds to an optical axis offset that could reduce the distance measurement accuracy of the optical detection device 10 below a predetermined accuracy. The predetermined accuracy is, for example, a pre-assumed error rate, such as ±5%. Notification of the optical axis offset is performed to the user of the optical detection device 10. If the optical detection device 10 is installed in a vehicle 50, notification can be provided via an information display device or voice prompting prompt inspection. Furthermore, the second reference offset Dr1 is the first determination value, and the first reference offset Dr2 is the second determination value.

[0060] According to the optical detection device 10 of the second embodiment described above, in addition to the various advantages obtained by the optical detection device 10 of the first embodiment, the optical axis offset in the horizontal and vertical directions, the optical axis offset in the rotational direction centered on the optical axis, and the optical axis offset in the direction of the orthogonal axis perpendicular to the optical axis can be determined, thereby further improving the accuracy of determining the optical axis offset. Since the accuracy of determining the optical axis offset is further improved, the yield of the optical detection device 10 can be increased, the accuracy of analyzing the optical axis offset that changes over time can be improved, and the prediction of the maintenance period required for the optical detection device 10 can be improved. In addition, the orthogonal axis perpendicular to the optical axis is a virtual orthogonal axis perpendicular to the optical axis in the optical system related to the focus, mainly in the lens or the light receiving element array 22. The optical axis offset in the direction of the orthogonal axis brings about blurring that accompanies the change in the relative distance between the lens and the light receiving element array 22. The various optical axis offset methods described in the second embodiment can be detected in any combination, or in all combinations.

[0061] In the above description, it is limited to the notification of the optical axis offset and the prediction of the occurrence of the optical axis offset, but the optical detection device 10 may also have a structure that can change the light-receiving pixels 230 used for light processing according to the manner of the detected optical axis offset. That is, the optical axis offset can be detected in more detail, so the light-receiving pixels used for light processing can be appropriately changed. The changeable structure includes: a method of changing the setting of the light-receiving pixels 230 for light processing in the optical detection device 10; a method of the optical detection device 10 itself changing the setting of the light-receiving pixels 230 according to the manner of the optical axis offset, that is, the horizontal, vertical, and optical axis offset around the optical axis. Use Figure 12 The changes in the light receiving area are explained in detail. Figure 12In the figure, the light receiving area ORP used as a reference, that is, before the optical axis offset occurs, is indicated by a dotted line. In the above-mentioned embodiments, the light receiving area ORP is composed of four light receiving blocks RB1, RB2, RB3, and RB4. When there is no optical axis offset around the optical axis, and an optical axis offset occurs in the horizontal direction HD and the vertical direction VD, and a light intensity spot appears in the area CH1 indicated by the dotted line, the light receiving pixels 230 corresponding to the area CH1 are used for light reception processing. In this case, the light receiving blocks RB1, RB2, RB3, and RB4 are selected to have the same vertical and horizontal configuration as when constituting the light receiving area ORP. When an optical axis offset occurs in the rotation direction with the optical axis as the rotation center, and a light intensity spot appears in the area CH2 indicated by the dotted line, the light receiving pixels 230 corresponding to the area CH2 are used for light reception processing. In this case, since region CH2 is tilted relative to the vertical direction VD and the horizontal direction HD, the light-receiving blocks RB1, RB2, RB3, and RB4 are selected to form a stepped pattern so as to coincide with or approximate region CH2, thereby defining a light-receiving area corresponding to region CH2. In this manner, when the light-receiving area ORP is formed by multiple light-receiving blocks, even if optical axis offset occurs horizontally, vertically, or around the optical axis, the light-receiving area can be modified in accordance with the optical axis offset, thereby suppressing or preventing a decrease in detection accuracy in the optical detection device 10. As a result, the detection accuracy of the optical detection device 10 can be maintained for a longer period than before. Furthermore, since optical axis offset, which accompanies changes in the relative distance, or relative position, between the lens and the light-receiving element array 22 detected due to blurring, requires hardware correction, this correction is typically performed by maintenance personnel. However, if at least one of the lens and the light-receiving element array 22 includes an actuator, the relative distance between the lens and the light-receiving element array 22 can also be corrected by activating the actuator.

[0062] Other implementations:

[0063] (1) In each of the above-mentioned embodiments, both the calculation of the predicted time period at which the optical axis offset occurs and the determination and notification of the optical axis offset are performed, but only one of them may be performed. In the case where only the calculation of the predicted time period at which the optical axis offset occurs is performed, by performing a notification corresponding to the calculated predicted time period, it is possible to take countermeasures before the optical axis offset occurs. Even in the case where only the determination and notification of the optical axis offset are performed, it is possible to perform the determination of the optical axis offset early using the optical detection device 10 alone. In the case where both the calculation of the predicted time period at which the optical axis offset occurs and the determination and notification of the optical axis offset are performed, it is possible to determine the occurrence of the optical axis offset early and notify the user even if countermeasures corresponding to the calculated predicted time period are not taken.

[0064] (2) In each of the above embodiments, the optical detection device 10 that performs the optical axis offset determination process is implemented by the CPU 101 executing the optical axis offset determination program Pr1, but it can also be implemented in hardware by a pre-programmed integrated circuit or discrete circuit. That is, the control unit and the method thereof in each of the above embodiments can also be implemented by a dedicated computer, which is provided by a processor and a memory that are programmed to execute one or more functions embodied by a computer program. Alternatively, the control unit and the method thereof described in the present disclosure can also be implemented by a dedicated computer provided by a processor that is configured by one or more dedicated hardware logic circuits. Alternatively, the control unit and the method thereof described in the present disclosure can also be implemented by one or more dedicated computers, which are composed of a combination of a processor and a memory that are programmed to execute one or more functions, and a processor composed of one or more hardware logic circuits. In addition, the computer program can also be stored as an instruction executed by a computer in a non-transient tangible recording medium that can be read by a computer.

[0065] The present disclosure has been described above based on the embodiments and variations, but the embodiments of the invention described above are for facilitating understanding of the contents of the present disclosure and do not limit the present disclosure. The present disclosure can be changed and improved without departing from its main purpose and claims, and its equivalents are included in the present disclosure. For example, in order to solve part or all of the above-mentioned problems, or to achieve part or all of the above-mentioned effects, the technical features in the embodiments and variations corresponding to the technical features in the various modes recorded in the invention content column can be appropriately replaced or combined. In addition, as long as the technical feature is not described as a necessary structure in this specification, it can be appropriately deleted.

Claims

1. An optical detection device comprising: a light-emitting portion having a plurality of light-emitting elements; a light receiving unit including a light receiving element array formed of a plurality of light receiving pixels that receive reflected light corresponding to the light irradiated by the light emitting unit; a storage unit for storing a reference light-receiving area in the light-receiving element array corresponding to a generation position of a light intensity spot included in the irradiation light of the light-emitting unit; as well as a determination unit for determining an optical axis offset based on a shift in the light intensity spot of the reference light receiving area and the light intensity spot of the detection light receiving area of the reflected light of the irradiated light in the light receiving element array, wherein the shift in the light intensity spot determines whether the positions of the light intensity spots coincide with each other; The light intensity spot is formed by the difference in light emission intensity between an overlapping area of the light emitted by the plurality of light emitting elements and an area not emitted by the light emitted by the plurality of light emitting elements.

2. The optical detection device according to claim 1, wherein: The plurality of light-receiving pixels are arranged without gaps in an arrangement direction of the plurality of light-emitting elements so that light intensity spots included in the reflected light are received by the plurality of light-receiving pixels.

3. The optical detection device according to claim 1 or 2, wherein: The plurality of light-receiving pixels are arranged without gaps in a direction perpendicular to the arrangement direction of the plurality of light-emitting elements, so that light intensity spots included in the reflected light are received by the plurality of light-receiving pixels.

4. The optical detection device according to claim 1, wherein: The size of each of the plurality of light-receiving pixels is set so that the plurality of light-receiving pixels receive a light intensity spot included in the reflected light.

5. The optical detection device according to claim 1 or 2, wherein: The determination unit determines the detection light receiving area using a difference between the light intensity of the light intensity spot and the light intensity of the reflected light. The optical detection device according to claim 5 , wherein: The determination unit learns the difference using the light intensity of the light intensity spot and the light intensity of the reflected light.

7. The optical detection device according to claim 2, wherein: When the amount of deviation between the reference light receiving area and the detection light receiving area is larger than a predetermined first determination value, the determination unit determines that the optical axis is deviated and executes a notification process of the optical axis deviation.

8. The optical detection device according to claim 7, wherein: The determination unit calculates a predicted time when the optical axis shift occurs when the amount of shift between the reference light receiving area and the detection light receiving area is smaller than the first determination value and larger than a predetermined second determination value.

9. The optical detection device according to claim 1, wherein: The determination unit calculates a predicted time when the optical axis shift occurs when the amount of shift between the reference light receiving area and the detection light receiving area is smaller than a first determination value serving as a determination value for optical axis shift and larger than a predetermined second determination value.

10. A method for determining optical axis deviation in an optical detection device. A detection light receiving area is obtained by a light receiving unit, which is provided with the light receiving element array, for detecting a light intensity spot included in the reflected light of the irradiated light. The light receiving unit includes the light receiving element array, and the light receiving element array is formed of a plurality of light receiving pixels that receive reflected light corresponding to the irradiated light of the light emitting unit having a plurality of light emitting elements. Acquiring a reference light receiving area in the light receiving element array prepared in advance and corresponding to a generation position of a light intensity spot included in the irradiation light, The optical axis deviation is determined by using the deviation of the light intensity spot to determine whether the reference light receiving area and the detection light receiving area are aligned with each other. The light intensity spot is formed by the difference in light emission intensity between an overlapping area of the light emitted by the plurality of light emitting elements and an area not emitted by the light emitted by the plurality of light emitting elements.

Images