WO2023153451A1

WO2023153451A1 - Measurement device

Info

Publication number: WO2023153451A1
Application number: PCT/JP2023/004229
Authority: WO
Inventors: 和也本橋; 幸雄林; 義朗伊藤; 秀倫曽根; 祐太春瀬
Original assignee: 株式会社小糸製作所
Priority date: 2022-02-09
Filing date: 2023-02-08
Publication date: 2023-08-17

Abstract

A measurement device (1) comprises: a light source (12); a light-projecting optical system (14) that irradiates a measurement area (50) with light from the light source (12); and a light-receiving unit (20) that receives light reflected from the measurement area (50). The light-projecting optical system (14): has a connected lens (15) formed by connecting a first lens element (151) having an optical axis shifted in a first direction and a second lens element (152) having an optical axis shifted in the opposite direction to the first lens element (151); irradiates a first measurement area (51) with the light from the light source (12) through the second lens element (152); and irradiates a second measurement area (52), which includes an overlapping area (53) overlapping the first measurement area (51), with the light from the light source (12) through the second lens element (12).

Description

measuring device

The present disclosure relates to measuring devices.

Patent Document 1 describes a distance measuring device that measures the distance to a reflecting object based on the time of flight of light from the time when pulsed light is emitted until the time when reflected light is received.

Japanese Patent Application Laid-Open No. 2021-152536

In the device described in Patent Document 1, the light is scanned by rotating the mirror, and the reflected light returned to the mirror is received by the light receiving unit. However, a movable part that rotates a mirror is likely to cause a failure. On the other hand, when irradiating or receiving light without using a movable part, there is a problem that the measurable range (measurement area) becomes narrow.

The purpose of the present disclosure is to expand the measurement area that can be irradiated with light without using a movable part. A further object of the present disclosure is to expand the measurement area capable of receiving light without using a movable part.

A measurement apparatus according to one aspect of the present disclosure includes a light source, a light projecting optical system that irradiates a measurement area with light from the light source, and a light receiving unit that receives reflected light from the measurement area. The optical system for light includes a coupling lens in which a first lens element whose optical axis is shifted in a first direction and a second lens element whose optical axis is shifted in a direction opposite to the first lens element are connected. irradiating the light from the light source onto the first measurement area through the first lens element, and causing the light from the light source to overlap the first measurement area through the second lens element A second measurement area including the overlap area is illuminated.

A measuring device according to another aspect of the present disclosure includes an irradiation unit that irradiates a measurement area with light, a light receiving sensor, and a light receiving optical system that causes the light receiving sensor to receive reflected light from the measurement area, The light-receiving optical system is a coupling lens in which a first lens element whose optical axis is shifted in a first direction and a second lens element whose optical axis is shifted in a direction opposite to that of the first lens element are connected. and causing the light receiving element of the light receiving sensor to receive the reflected light from the first measurement area via the first lens element, and a second measurement including an overlapping area overlapping the first measurement area The reflected light from the area is received by the light receiving element via the second lens element.

In addition, the problems disclosed by the present application and their solutions are clarified in the section of the mode for carrying out the invention and the drawings.

According to the present disclosure, the measurement area that can be irradiated with light can be expanded without using a movable part. Furthermore, according to the present disclosure, it is possible to expand the measurement area capable of receiving light without using a movable part.

FIG. 1 is an explanatory diagram of the overall configuration of the measuring device 1. As shown in FIG. FIG. 2 is an explanatory diagram of the configuration of the irradiation unit 10 of the first embodiment. FIG. 3A is an explanatory diagram of the light source 12. FIG. FIG. 3B is an explanatory diagram of the measurement area 50. As shown in FIG. FIG. 3C is an explanatory diagram of an example in which the measuring device 1 is mounted on a vehicle. FIG. 4 is a perspective view of the coupling lens 15. FIG. FIG. 5A is an explanatory diagram of the measurement area 50. FIG. FIG. 5B is an explanatory diagram of the measurement area 50. FIG. FIG. 6A is an explanatory diagram of the optical conditions of the irradiation section. FIG. 6B is an explanatory diagram of the optical conditions of the irradiation section. FIG. 7 is an explanatory diagram of the light receiving sensor 22. As shown in FIG. FIG. 8 is a timing chart for explaining an example of the measuring method. FIG. 9A is an explanatory diagram of another example of the light receiving sensor 22. FIG. FIG. 9B is an explanatory diagram of the signal processing unit 362. As shown in FIG. FIG. 9C is an explanatory diagram of a histogram. FIG. 10A is an explanatory diagram showing the relationship between the light emitting area of the light source 12 and the measurement area 50. FIG. FIG. 10B is an explanatory diagram showing the relationship between the light emitting area of the light source 12 and the measurement area 50. As shown in FIG. 11A and 11B are explanatory diagrams of the state during measurement of the region H, which is the overlapping area 53. FIG. FIG. 12 is an explanatory diagram of another measuring method. FIG. 13 is an explanatory diagram of the light receiving section 20 of the first embodiment. FIG. 14 is an explanatory diagram of the light receiving sensor 22. As shown in FIG. 15 is a perspective view of the coupling lens 25. FIG. FIG. 16A is an explanatory diagram of the measurement area 50. FIG. FIG. 16B is an explanatory diagram of the measurement area 50. FIG. FIG. 17A is an explanatory diagram showing the relationship between the pixels 221 (light receiving areas) of the light receiving sensor 22 and the measurement area 50. FIG. FIG. 17B is an explanatory diagram showing the relationship between the pixels 221 (light receiving areas) of the light receiving sensor 22 and the measurement area 50. FIG. FIG. 18A is an explanatory diagram of the optical conditions of the light receiving section. FIG. 18B is an explanatory diagram of the optical conditions of the light receiving section. FIG. 19A is an explanatory diagram of an example of a measurement method. FIG. 19B is an explanatory diagram of an example of the measurement method. FIG. 19C is an explanatory diagram of an example of the measurement method. FIG. 20 is an explanatory diagram of the signal processing section 362 when measuring the overlapping area 53. As shown in FIG. FIG. 21 is an explanatory diagram of another signal processing section 362 when measuring the overlapping area 53. As shown in FIG.

Embodiments for carrying out the present disclosure will be described below with reference to the drawings. In the following description, the same or similar configurations may be denoted by common reference numerals, and redundant description may be omitted.

===First embodiment===
<Overall composition>
FIG. 1 is an explanatory diagram of the overall configuration of the measuring device 1. As shown in FIG.

The measuring device 1 is a device that measures the distance to the object 90 . The measuring device 1 is a device that functions as a so-called LiDAR (Light Detection and Ranging, Laser Imaging Detection and Ranging). The measurement apparatus 1 emits measurement light, detects the reflected light reflected by the surface of the object 90, and measures the time from the emission of the measurement light to the reception of the reflected light. The distance of is measured by the TOF method (Time of flight). The measuring device 1 has an irradiation section 10 , a light receiving section 20 and a control section 30 .

The irradiation unit 10 irradiates the measurement light toward the object 90 . The irradiation unit 10 irradiates a measurement area 50 (described later) with measurement light at a predetermined angle of view. The irradiation section 10 has a light source 12 and a projection optical system 14 . The light source 12 emits light. The light source 12 is composed of, for example, a surface emitting laser (VCSEL). The light projection optical system 14 is an optical system that irradiates the measurement area 50 with light emitted from the light source 12 . A detailed configuration of the irradiation unit 10 will be described later.

The light receiving unit 20 receives reflected light from the object 90 . The light receiving section 20 receives reflected light from the measurement area 50 . The light receiving section 20 has a light receiving sensor 22 and a light receiving optical system 24 . A detailed configuration of the light receiving unit 20 will be described later.

The control unit 30 controls the measurement device 1 . The control unit 30 controls irradiation of light from the irradiation unit 10 . Also, the control unit 30 measures the distance to the object 90 by the TOF method (time of flight) based on the output result of the light receiving unit 20 . The control unit 30 has an arithmetic device and a storage device (not shown). The arithmetic device is, for example, an arithmetic processing device such as a CPU or GPU. A part of the arithmetic device may be composed of an analog arithmetic circuit. A storage device is configured by a main storage device and an auxiliary storage device, and stores programs and data. Various processes for measuring the distance to the object 90 are executed by the arithmetic device executing the program stored in the storage device. The figure shows functional blocks for various processes.

The control unit 30 has a setting unit 32, a timing control unit 34, and a distance measurement unit 36. The setting unit 32 performs various settings. The timing control section 34 controls the processing timing of each section. For example, the timing control unit 34 controls the timing of emitting light from the light source 12 and the like. The distance measuring unit 36 measures the distance to the object 90 . The distance measurement section 36 has a signal processing section 362 , a time detection section 364 and a distance calculation section 366 . The signal processing section 362 processes the output signal of the light receiving sensor 22 . The time detection unit 364 detects the time of flight of light (time from irradiation of light to arrival of reflected light). The distance calculator 366 calculates the distance to the object 90 . Note that the processing of the control unit 30 will be described later.

<Regarding the irradiation unit 10 of the first embodiment>
FIG. 2 is an explanatory diagram of the configuration of the irradiation unit 10 of the first embodiment. As already explained, the irradiation unit 10 has the light source 12 and the light projecting optical system 14 .

In the following description, the direction along the optical axis of the projection optical system 14 is the Z direction. Note that the object 90 to be measured by the measuring device 1 is separated from the measuring device 1 in the Z direction. Also, the direction perpendicular to the Z direction and the direction in which the first lens element 151 and the second lens element 152 constituting the connecting lens 15 (described later) are arranged is defined as the Y direction. A direction perpendicular to the Z direction and the Y direction is defined as the X direction.

FIG. 3A is an explanatory diagram of the light source 12. FIG.
The light source 12 has a light emitting surface parallel to the XY plane (surface parallel to the X direction and the Y direction). The light emitting surface is configured in a rectangular shape. The light emitted from the light source 12 is applied to the measurement area 50 via the light projecting optical system 14 .

The projection optical system 14 has a coupling lens 15 . FIG. 4 is a perspective view of the coupling lens 15. FIG.
The connecting lens 15 is an optical component in which the first lens element 151 and the second lens element 152 are connected. The first lens element 151 and the second lens element 152 are convex lens-shaped parts (optical elements), and are arranged side by side in the Y direction. The focal length of the first lens element 151 and the focal length of the second lens element 152 are the same. Also, the first lens element 151 and the second lens element 152 each have an optical axis along the Z direction. The optical axis of the first lens element 151 is shifted in the +Y direction with respect to the optical axis of the projection optical system 14 (projection lens 16 described later). On the other hand, the optical axis of the second lens element 152 is shifted in the -Y direction with respect to the optical axis of the projection optical system . That is, the optical axis of the second lens element 152 is shifted in the direction opposite to that of the first lens element 151 .

The projection optical system 14 also has a projection lens 16 . Projection lens 16 is a lens arranged between light source 12 and coupling lens 15 . By having the projection lens 16 in the projection optical system 14 , the light from the light source 12 can be projected onto a wide measurement area 50 . Further, since the light projecting optical system 14 has the projection lens 16 , the light from the light source 12 can be formed into a rectangular light distribution pattern and projected onto the measurement area 50 . The distance between projection lens 16 and light source 12 is closer than the focal length of projection lens 16 . Although the light rays directed from the projection lens 16 to the coupling lens 15 diverge, the spreading of the light emitted from the coupling lens 15 toward the measurement area 50 is suppressed by the convex lens-shaped first optical element and the second optical element ( Light close to collimated light is emitted from the light projecting optical system 14 to the measurement area 50).

FIG. 3B is an explanatory diagram of the measurement area 50. FIG. 5A and 5B are explanatory diagrams of the measurement area 50. FIG. FIG. 5A is an explanatory diagram of how the light from the light source 12 irradiates the first measurement area 51 through the first lens element 151. FIG. FIG. 5B is an explanatory diagram of how light from the light source 12 is irradiated onto the second measurement area 52 via the second lens element 152 .

The measurement area 50 is composed of a first measurement area 51 and a second measurement area 52 . The first measurement area 51 is an area irradiated with the light of the light source 12 via the first lens element 151 (in other words, the first lens element 151 irradiates the first measurement area 51 with the light of the light source 12). optical element). The second measurement area 52 is an area irradiated with the light of the light source 12 via the second lens element 152 (in other words, the second lens element 152 irradiates the second measurement area 52 with the light of the light source 12). optical element). Since the first lens element 151 and the second lens element 152 are arranged side by side in the Y direction, the first measurement area 51 and the second measurement area 52 are arranged to be shifted in the Y direction. As a result, the measurement area 50 can be set long in the Y direction (in other words, a wide range in the Y direction can be irradiated with light).

In the first embodiment, the first measurement area 51 and the second measurement area 52 overlap. In the following description, a region where the first measurement area 51 and the second measurement area 52 overlap is called an "overlapping area 53". By providing the overlapping area 53 , it is possible to prevent the formation of a region where light cannot be irradiated between the first measurement area 51 and the second measurement area 52 .

As shown in FIG. 3B, when the measurement area 50 is viewed from the Z direction, the measurement area 50 has predetermined angles of view in the X and Y directions. In the first embodiment, the ratio of the Y-direction length to the X-direction length (so-called aspect ratio) of the measurement area 50 is the ratio of the Y-direction length to the X-direction length of the light source 12 (so-called aspect ratio). That is, in the first embodiment, the measurement area 50 can be set longer in the Y direction than the shape of the light source 12 (in other words, light can be emitted over a wider range in the Y direction).

As shown in FIG. 5A, of the light emitting surface of the light source 12, a region that emits light to irradiate the overlapping area 53 via the first lens element 151 is called a "first region 121". Further, as shown in FIG. 5B, a region of the light emitting surface of the light source 12 that emits the light to irradiate the overlapping area 53 via the second lens element 152 is called a "second region 122".

In the overlapping area 53, light passing through the first lens element 151 and light passing through the second lens element 152 can be irradiated. When the first region 121 and the second region 122 of the light source 12 are caused to emit light at the same time, in the overlapping area 53, the light emitted through the first lens element 151 and the light emitted through the second lens element 152 can be superimposed. Therefore, in the overlapping area 53 , the irradiation intensity of light can be increased compared to the measurement area 50 excluding the overlapping area 53 .

As shown in FIG. 3B, the overlapping area 53 (hatched area) where the irradiation intensity is relatively high is located in the center of the measurement area 50 in the Y direction. By causing the light emitting surface of the light source 12 to emit light collectively (that is, by simultaneously causing the first region 121 and the second region 122 of the light source 12 to emit light), as shown in FIG. 53) can be increased in intensity.

FIG. 3C is an explanatory diagram of an example in which the measuring device 1 is mounted on a vehicle. As shown in the figure, when the measuring device 1 is mounted on a vehicle, it is desirable to measure the distance with a wide field of view in relatively close proximity. On the other hand, in the first embodiment, as shown in FIG. 3B, the aspect ratio of the measurement area 50 can be increased, which is advantageous for distance measurement in a wide field of view.
On the other hand, as shown in FIG. 3C, when the measuring device 1 is mounted on a vehicle, the area required to measure the distance to a long distance is allowed to be a relatively narrow range. It is desirable to be able to irradiate intense light. On the other hand, in the first embodiment, as shown in FIG. 3B, the intensity of the light in the overlapping area 53 of the measurement area 50 can be increased, which is advantageous for measuring a long distance.

<Regarding the optical conditions of the irradiation unit 10>
6A and 6B are explanatory diagrams of the optical conditions of the irradiation unit 10. FIG. FIG. 6A is an explanatory diagram of the relationship between the light source 12 and the projection lens 16. FIG. FIG. 6B is an explanatory diagram of the relationship between the virtual image 12 ′ of the light source 12 and the coupling lens 15 .

As shown in FIG. 6A, let the focal length of the projection lens 16 be fA1. Also, let LA1 be the distance from the principal point of the projection lens 16 to the light source 12 . Also, the half length of the light source 12 in the Y direction is yA (the length from the optical axis of the light projecting optical system 14 to the end of the light source 12 is yA).

In the first embodiment, the distance LA1 from the principal point of the projection lens 16 to the light source 12 is smaller than the focal length fA1 of the projection lens 16 (LA1<fA1). Since the light source 12 is arranged closer than the focal point of the projection lens 16, the virtual image 12' of the light source 12 (the image of the light source 12 by the projection lens 16) is on the opposite side of the light source 12 when viewed from the projection lens 16 (Fig. left side of the light source 12).

Assuming that the distance from the principal point of the projection lens 16 to the virtual image 12' is LA', the relationship between LA1, LA' and fA1 is given by the following equation (A1).
(1/LA1)-(1/LA')=1/fA1 (A1)

Therefore, the distance LA' from the principal point of the projection lens 16 to the virtual image 12' is given by the following equation (A2).
LA'=(LA1×fA1)/(fA1−LA1) (A2)

When the length from the optical axis of the light projecting optical system 14 to the edge of the virtual image 12' of the light source 12 is yA', yA' is given by the following equation (A3).
yA′=yA×(LA′/LA1)
=yA×fA1/(fA1−LA1) (A3)

Next, let the focal length of the first lens element 151 and the second lens element 152 be fA2. As shown in FIG. 6B, let LA2 be the distance from the principal point of the coupling lens 15 (the principal point of the first lens element 151 or the second lens element 152) to the virtual image 12'. Here, assuming that the connecting lens 15 irradiates the light of the virtual image 12' to the distant irradiation area as shown in FIG. 6B, the relationship between the focal length fA2 and the distance LA2 is expressed by the following equation (A4).
LA2=fA2 (A4)

The distance between the principal point of the projection lens 16 and the principal point of the coupling lens 15 is dA. Here, since the distance LA2 corresponds to a value obtained by adding the distance dA to the distance LA', the relationship between the focal lengths fA1 and fA2 and each distance is expressed by the following equation (A5).
(LA1×fA1)/(fA1−LA1)+dA=fA2 (A5)

Also, as shown in FIG. 6B, the distance between the optical axis of the projection optical system 14 (projection lens 16) and the optical axis of the first lens element 151 (or the second lens element 152) is tA. tA”. Here, in order to form the overlapping area 53, the first measurement area 51 and the second measurement area 52 need to overlap. Therefore, the shift amount tA needs to be smaller than the length yA' from the optical axis of the projection optical system 14 to the edge of the virtual image 12' of the light source 12 (tA<yA'). In other words, in order to form the overlapping area 53, the shift amount tA of each of the first lens element 151 and the second lens element 152 of the coupling lens 15 must satisfy the following equation (A6).
tA<yA×fA1/(fA1−LA1) (A6)

<Measurement example 1>
FIG. 7 is an explanatory diagram of the light receiving sensor 22. As shown in FIG.

The light receiving sensor 22 has a plurality of pixels 221 arranged two-dimensionally. For example, in the case of the VGA light receiving sensor 22, 480×640 pixels 221 are two-dimensionally arranged. Each pixel 221 has a light receiving element, and the light receiving element outputs a signal according to the amount of light received. The control unit 30 acquires an output signal for each pixel 221 .

FIG. 8 is a timing chart for explaining an example of the measurement method.

The control unit 30 (timing control unit 34) causes the light source 12 of the irradiation unit 10 to emit pulsed light at a predetermined cycle. The upper part of FIG. 8 shows the timing (emission timing) at which the light source 12 emits pulsed light. Here, it is assumed that light is emitted from the entire light emitting surface of the light source 12 . The light emitted from the light source 12 is applied to the measurement area 50 via the light projecting optical system 14 . The light reflected by the surface of the object 90 within the measurement area 50 is received by the light receiving sensor 22 via the light receiving optical system 24 . Each pixel 221 of the light receiving sensor 22 receives the pulsed reflected light. The center of FIG. 8 shows the timing (arrival timing) at which the pulsed reflected light arrives. Each pixel 221 outputs a signal corresponding to the amount of light received. The output signal of each pixel 221 is shown in the lower part of FIG.

The distance measurement unit 36 (signal processing unit 362) of the control unit 30 detects the arrival timing of the reflected light based on the output signal of each pixel 221. For example, the signal processing unit 362 detects the arrival timing of reflected light based on the peak timing of the output signal of each pixel 221 . Note that the signal processing unit 362 may obtain the arrival timing of the reflected light based on the peak of the signal obtained by cutting the DC component of the output signal of the pixel 221 in order to remove the influence of ambient light (for example, sunlight). .

Next, the distance measurement unit 36 (time detection unit 364) detects the time Tf from when the light is emitted to when the reflected light arrives, based on the light emission timing and the light arrival timing. The time Tf corresponds to the time it takes the light to make a round trip between the measurement device 1 and the object 90 . Then, the distance measurement unit 36 (distance calculation unit 366) calculates the distance L to the object 90 based on the time Tf. When the time from irradiation of light to arrival of reflected light is Tf, and the speed of light is C, the distance L is L=C×Tf/2. The control unit 30 generates a distance image by calculating the distance to the object 90 for each pixel 221 based on the time Tf detected for each pixel 221 .

<Measurement example 2>
FIG. 9A is an explanatory diagram of another example of the light receiving sensor 22. FIG.
The light receiving sensor 22 has a plurality of pixels 221 arranged two-dimensionally. Each pixel 221 has a plurality of light receiving elements 222 . Here, each pixel 221 has nine SPADs (Single Photon Avalanche Diodes) arranged three in the X direction and three in the Y direction as the light receiving elements 222 . A light-receiving element 222 composed of a SPAD outputs a pulse signal when it detects a photon.

9B is an explanatory diagram of the signal processing unit 362. FIG. The signal processor 362 has an adder 362A, a comparator 362B, and a histogram generator 362C. Here, the processing signal unit generates a histogram used in Time Correlated Single Photon Counting (TCSPC) based on the output signal of each pixel 221 of the light receiving sensor 22 .

The adder 362A adds the output signals of the plurality of light receiving elements 222 (SPAD) forming the pixel 221. The adder 362A may adjust (shape) the pulse widths output from the light receiving elements 222 and then add the output signals of the plurality of light receiving elements 222 . The comparator 362B compares the output signal of the adder 362A with a threshold, and outputs a signal when the output signal of the adder 362A is greater than or equal to the threshold. The timing at which the comparator 362B outputs a signal is considered to be the timing at which the light receiving element 222 (SPAD) of the light receiving sensor 22 detects light.

By the way, the photons of disturbance light are temporally randomly incident on each light receiving element 222 . On the other hand, the photons of the reflected light are incident on each of the light receiving elements 222 after a predetermined delay time (flight time according to the distance to the object 90) after light irradiation. Therefore, when photons of disturbance light are incident on the light receiving element 222 at random in terms of time, the probability that the output signal of the adder 362A is equal to or higher than the threshold is low. On the other hand, when the photons of the reflected light are incident on the light receiving element 222, the multiple light receiving elements 222 forming the pixel 221 detect the photons at the same time, so the output signal of the adder 362A is highly likely to be equal to or greater than the threshold. Therefore, the output signals of the plurality of light receiving elements 222 are added by the adding section 362A, and the output signal of the adding section 362A is compared with the threshold value by the comparing section 362B, whereby the light receiving element 222 (SPAD) detects the reflected light. Measure the time that can be considered.

FIG. 9C is an explanatory diagram of a histogram. The horizontal axis in the figure is time, and the vertical axis is frequency (number of times). Based on the output of the comparison unit 362B, the histogram generation unit 362C repeatedly measures the time that the light receiving element 222 (SPAD) of the light receiving sensor 22 detects light, and increments the frequency (number of times) associated with that time. to generate a histogram. When the frequency (number of times) is incremented, the histogram generator 362C may increase the number corresponding to the output signal (added value) of the adder 362A instead of increasing the number by one.

Note that the setting unit 32 (see FIG. 1) presets the number of integrations for generating the histogram. The timing control unit 34 causes the light source 12 of the irradiation unit 10 to emit pulsed light a plurality of times according to the set number of times of integration. A signal is output once or a plurality of times from the adder 362A for one emission of pulsed light from the light source 12 . The histogram generation unit 362C generates a histogram by incrementing the frequency (number of times) according to the output signal of the comparison unit 362B until the set number of times of accumulation is reached.

After generating the histogram, the distance measurement unit 36 (time detection unit 364) detects the time Tf from when the light is emitted until the reflected light arrives, based on the histogram. As shown in FIG. 9C, the distance measurement unit 36 (time detection unit 364) detects the time corresponding to the frequency peak of the histogram, and sets that time as time Tf. Then, the distance measuring section 36 (distance calculating section 366) calculates the distance to the object 90 based on the time Tf.

Normally, when measuring the distance of a distant object 90, the light illuminating the object 90 is weakened. Need to increase the number of times. However, if the number of integrations is increased, it will take time to complete the histogram, so it will take time to measure the distance (in other words, the frame rate (FPS) of the distance image will deteriorate). On the other hand, in the first embodiment, the intensity of the light in the overlapping area 53 of the measurement area 50 can be increased. There is an advantage that it can be completed in

<Modified Example of Light Emission Control of Light Source 12>
In the first embodiment described above, the light source 12 collectively emits light from the light emitting surface. However, the light source 12 may be controlled so as to emit light from a part of the light emitting surface.

10A and 10B are explanatory diagrams showing the relationship between the light emitting area of the light source 12 and the measurement area 50. FIG. FIG. 10A is an explanatory diagram showing the relationship between the light emitting region of the light source 12 and the measurement area 50 when the first measurement area 51 is irradiated with light through the first lens element 151. FIG. FIG. 10B is an explanatory diagram showing the relationship between the light emitting region of the light source 12 and the measurement area 50 when the second measurement area 52 is irradiated with light through the second lens element 152. As shown in FIG. On the right side of each measurement area 50 in FIGS. 10A and 10B, the corresponding light emitting area of the light source 12 is shown.

The light source 12 is divided into a plurality of light-emitting regions in the Y direction, here divided into 12 light-emitting regions (light-emitting regions #1 to #12). The number of light emitting regions of the light source 12 divided in the Y direction is not limited to twelve. Also, the measurement area 50 is divided into a plurality of regions (regions A to P) in the Y direction, and is divided into 16 regions here. Note that the number of regions of the measurement area 50 divided in the Y direction is not limited to 16.

As shown in FIG. 10A, the first measurement area 51 corresponds to regions A to L. The light emitting areas #1 to #12 of the light source 12 correspond to the areas L to A of the first measurement area 51, respectively. For example, the light emitted from the light emitting region #5 of the light source 12 passes through the first lens element 151 and irradiates the region H of the measurement area 50 .

As shown in FIG. 10B, the second measurement area 52 corresponds to regions E to P. The light emitting areas #1 to #12 of the light source 12 correspond to the areas P to E of the second measurement area 52, respectively. For example, the light emitted from the light emitting region #5 of the light source 12 passes through the second lens element 152 and irradiates the region L of the measurement area 50 . In this way, the light emitted from a certain light emitting region (for example, light emitting region #5) of the light source 12 passes through the first lens element 151 and the second lens element 152 of the coupling lens 15 and passes through the two regions of the measurement area 50. (eg area H and area L).

As shown in FIGS. 10A and 10B, the overlapping area 53 corresponds to the areas E to L. As shown in FIG. 10A, the light emitted from the light emitting regions #8 to #1 of the light source 12 passes through the first lens element 151 and irradiates the regions E to L, which are the overlapping area 53. As shown in FIG. Therefore, the light emitting regions #1 to #8 of the light source 12 correspond to the first region 121 described above. Further, as shown in FIG. 10B, light emitted from the light emitting regions #12 to #5 of the light source 12 passes through the second lens element 152 and irradiates the regions E to L, which are the overlapping area 53. As shown in FIG. Therefore, the light emitting regions #5 to #12 of the light source 12 correspond to the second region 122 described above.

FIG. 11 is an explanatory diagram of how the region H, which is the overlapping area 53, is measured. The area of the corresponding light source 12 is shown on the right side of each area of the measurement area 50 in the figure. In addition, a region of the corresponding measurement area 50 is shown on the left side of each pixel 221 of the light receiving sensor 22 in the drawing. Each pixel 221 of the light-receiving sensor 22 receives the reflected light from the corresponding region of the measurement area 50 (the image of the measurement area 50 is formed on the light-receiving surface of the light-receiving sensor 22 by the light-receiving optical system 24).

The area H of the overlapping area 53 is associated with the light emitting area #5 and the light emitting area #9 of the light source 12 . As shown in the figure, when measuring region H, the control unit 30 causes the light emitting region #5 and the light emitting region #9 of the light source 12 to emit light simultaneously. Thus, when measuring a specific region of the overlapping area 53, the control unit 30 simultaneously emits light from the two light emitting regions corresponding to that region.

The light emitted from the light emitting region #5 of the light source 12 irradiates the region H (first measurement area 51) and the region L (second measurement area 52). Moreover, the light emitted from the region #9 of the light source 12 is irradiated to the region D (first measurement area 51) and the region H (second measurement area 52). That is, since the light emitted from the regions #5 and #9 of the light source 12 overlaps the region H (overlapping area 53) that becomes the overlapping area 53, the intensity of the irradiated light increases.

The pixel #9 of the light receiving sensor 22 receives the reflected light from the area H of the measurement area 50 . Since the light emitted from the light emitting regions #5 and #9 of the light source 12 is superimposed on the region H, the intensity of the reflected light received by the pixel #9 of the light receiving sensor 22 can be increased.

It should be noted that in the description so far, the connecting lens 15 is used for the purpose of increasing the intensity of the light in the overlapping area 53 . However, the application of coupling lens 15 need not be to increase the intensity of light in overlapping area 53 .

For example, when measuring the region H, the control unit 30 emits light from the light emitting region #5 of the light source 12 and calculates the distance based on the light receiving result of the pixel #9 of the light receiving sensor 22. , and calculating the distance based on the light reception result of the pixel #9 of the light receiving sensor 22 may be performed separately. Then, the control unit 30 may calculate the distance by averaging the respective distance calculation results. Thus, coupling lens 15 may not be used for the purpose of increasing light intensity.

FIG. 12 is an explanatory diagram of another measuring method.

Light emitted from a specific light-emitting region of the light source 12 is irradiated onto the corresponding region of the first measurement area 51 and the corresponding region of the second measurement area 52 . In other words, the light emitted from the specific light emitting region of the light source 12 irradiates two regions of the measurement area 50 . For example, as shown in the figure, the light emitted from the light emitting region #5 of the light source 12 irradiates the region H (first measurement area 51) and the region L (second measurement area 52).

As shown in the figure, the pixel #9 of the light receiving sensor 22 corresponds to the area H of the measurement area 50 and receives reflected light from the area H. Further, the pixel #5 of the light receiving sensor 22 corresponds to the area L of the measurement area 50 and receives the reflected light from the area L. As shown in FIG.

In this measurement method, by emitting light from a certain light emitting area of the light source 12, it is possible to simultaneously measure the distance to the object 90 in two areas of the measurement area 50. Thus, coupling lens 15 need not be used to increase the intensity of light in overlap area 53 .

<Regarding the light receiving unit 20 of the first embodiment>
FIG. 13 is an explanatory diagram of the light receiving section 20 of the first embodiment. As already explained, the light receiving section 20 has the light receiving sensor 22 and the light receiving optical system 24 .

In the following description, the direction along the optical axis of the light receiving optical system 24 is the Z direction. Note that the object 90 to be measured by the measuring device 1 is separated from the measuring device 1 in the Z direction. Also, the direction perpendicular to the Z direction and the direction in which the first lens element 251 and the second lens element 252 constituting the connecting lens 25 (described later) are arranged is defined as the Y direction. A direction perpendicular to the Z direction and the Y direction is defined as the X direction.

FIG. 14 is an explanatory diagram of the light receiving sensor 22. As shown in FIG.
The light receiving sensor 22 has a light receiving surface parallel to the XY plane (a surface parallel to the X direction and the Y direction). The light receiving surface is configured in a rectangular shape. Reflected light arriving from the measurement area is irradiated onto the light receiving surface of the light receiving sensor 22 via the light receiving optical system 24 (an image of the measurement area 50 is formed on the light receiving surface of the light receiving sensor 22 by the light receiving optical system 24). ).

As shown in FIG. 7, the light receiving sensor 22 has a plurality of pixels 221 arranged two-dimensionally.

The light receiving optical system has a coupling lens 25 . 15 is a perspective view of the coupling lens 25. FIG.
The connecting lens 25 is an optical component that connects the first lens element 251 and the second lens element 252 . The first lens element 251 and the second lens element 252 are convex lens-shaped parts (optical elements), and are arranged side by side in the Y direction. The focal length of the first lens element 251 and the focal length of the second lens element 252 are the same. Also, the first lens element 251 and the second lens element 252 each have an optical axis along the Z direction. The optical axis of the first lens element 251 is shifted in the +Y direction with respect to the optical axis of the light-receiving optical system 24 (collecting lens 26 described later). On the other hand, the optical axis of the second lens element 252 is shifted in the -Y direction with respect to the optical axis of the light receiving optical system . That is, the optical axis of the second lens element 252 is shifted in the direction opposite to that of the first lens element 251 .

The light receiving optical system 24 also has a condenser lens 26 . The condenser lens 26 is a lens arranged between the light receiving sensor 22 and the coupling lens 25 . Since the light receiving optical system 24 has the condenser lens 26 , the light receiving sensor 22 can receive the reflected light from the wide measurement area 50 . Further, since the light receiving optical system 24 has the condenser lens 26 , an image of the rectangular measurement area 50 can be formed on the rectangular light receiving surface of the light receiving sensor 22 . The distance between the condenser lens 26 and the light receiving sensor 22 is shorter than the focal length of the condenser lens 26 .

16A and 16B are explanatory diagrams of the measurement area 50. FIG. FIG. 16A is an explanatory diagram of how the light receiving sensor 22 receives reflected light from the first measurement area 51 via the first lens element 251 . FIG. 16B is an explanatory diagram of how the light receiving sensor 22 receives reflected light from the second measurement area 52 via the second lens element 252 .

As shown in FIG. 3B, the measurement area 50 is composed of a first measurement area 51 and a second measurement area 52 . The first measurement area 51 is an area where the light sensor 22 receives reflected light via the first lens element 251 (in other words, the first lens element 251 receives the reflected light from the first measurement area 51 as a light sensor). 22). The second measurement area 52 is an area where the light sensor 22 receives reflected light via the second lens element 252 (in other words, the second lens element 252 receives the light reflected from the second measurement area 52 by the light sensor. 22). Since the first lens element 251 and the second lens element 252 are arranged side by side in the Y direction, the first measurement area 51 and the second measurement area 52 are arranged to be shifted in the Y direction. This makes it possible to set the measurement area 50 long in the Y direction (in other words, it is possible to receive reflected light over a wide range in the Y direction).

In the first embodiment, by providing the overlapping area 53, it is possible to prevent the formation of an area that cannot receive the reflected light between the first measurement area 51 and the second measurement area 52.

17A and 17B are explanatory diagrams showing the relationship between the pixels 221 (light receiving areas) of the light receiving sensor 22 and the measurement area 50. FIG. FIG. 17A is an explanatory diagram showing the relationship between the pixels 221 of the light receiving sensor 22 and the measurement area 50 when receiving reflected light from the first measurement area 51 via the first lens element 251. FIG. FIG. 17B is an explanatory diagram showing the relationship between the pixels 221 of the light receiving sensor 22 and the measurement area 50 when receiving the reflected light from the second measurement area 52 via the second lens element 252 . A region of the corresponding measurement area 50 is shown on the left side of each pixel 221 of the light receiving sensor 22 in the drawing. Each pixel 221 of the light receiving sensor 22 receives reflected light from the corresponding region of the measurement area 50 .

The light-receiving sensor 22 has a plurality of pixels 221 (light-receiving regions) arranged in the Y direction, and here, 12 pixels (pixels #1 to #12) are arranged in the Y direction. The number of pixels 221 arranged in the Y direction is not limited to 12 (for example, in the case of the VGA light receiving sensor 22, 640 pixels are arranged in the Y direction). Also, the measurement area 50 is divided into a plurality of regions (regions A to P) in the Y direction, and is divided into 16 regions here. Note that the number of regions of the measurement area 50 divided in the Y direction is not limited to 16.

As shown in FIG. 17A, the first measurement area 51 corresponds to regions A to L. Pixels #1 to #12 of the light receiving sensor 22 correspond to the regions L to A of the first measurement area 51, respectively. For example, the pixel #5 of the light receiving sensor 22 receives reflected light from the region H of the measurement area 50 via the first lens element 251 .

As shown in FIG. 17B, the second measurement area 52 corresponds to regions E to P. Pixels #1 to #12 of the light receiving sensor 22 correspond to the regions P to E of the second measurement area 52, respectively. For example, pixel #5 of the light receiving sensor 22 receives reflected light from the area L of the measurement area 50 via the second lens element 252 . In this way, a certain pixel (for example, pixel #5) of the light receiving sensor 22 is connected to two regions (for example, region H and Reflected light from the area L) can be received. In the following description, when a certain pixel (for example, pixel #5) of the light receiving sensor 22 can receive reflected light from two positions (for example, area H and area L) of the measurement area 50, the two positions ( For example, the position where the reflected light is received via the first lens element 251 (for example, the region H and the region L) is called a "first position", and the reflected light is received via the second lens element 252. A region (for example, region L) to be set may be referred to as a “second position”.

By the way, when a certain pixel of the light receiving sensor 22 can receive reflected light from two regions (first position and second position) of the measurement area 50, when the light receiving element of the pixel receives the reflected light, It is necessary to be able to determine from which of the first position and the second position the reflected light is received. Therefore, in the first embodiment, the control unit 30 is configured to be able to control the position on the measurement area 50 irradiated with light by controlling the irradiation unit 10 . Then, the controller 30 controls the irradiator 10 so as not to irradiate the first position and the second position with light at the same time. As a result, when the light receiving element of the pixel #5 of the light receiving sensor 22 receives the reflected light when the region H of the measurement area 50 is irradiated with light, the control unit 30 detects that the received light is from the region L. It is possible to calculate the distance of the object 90 in the area H based on the signal of the light receiving element of the pixel #5, assuming that the reflected light is not the reflected light but the reflected light from the area H. FIG.

As shown in FIGS. 17A and 17B, the overlapping area 53 corresponds to areas E to L. As shown in FIG. 17A, the pixels #8 to #1 of the light receiving sensor 22 receive reflected light from the areas E to L, which are the overlapping area 53, via the first lens element 251. As shown in FIG. Further, as shown in FIG. 17B, pixels #12 to #5 of the light receiving sensor 22 receive reflected light from areas E to L, which are the overlapping area 53, via the second lens element 252. As shown in FIG. Reflected light from a certain area (for example, area H) of the overlapping area 53 passes through the first lens element 251 and the second lens element 252 of the coupling lens 25 and passes through two pixels (for example, pixel #5 and pixel #5) of the light receiving sensor 22. Pixel #9) can receive light.

As shown in FIG. 3B, when the measurement area 50 is viewed from the Z direction, the measurement area 50 has predetermined angles of view in the X and Y directions. In the first embodiment, the ratio of the length in the Y direction to the length in the X direction (so-called aspect ratio) of the measurement area 50 is the ratio of the length in the Y direction to the length in the X direction of the light receiving sensor 22 ( so-called aspect ratio). That is, in the first embodiment, the measurement area 50 can be set longer in the Y direction than the shape of the light receiving sensor 22 (in other words, reflected light over a wide range in the Y direction can be received).

As shown in FIG. 16A, the area of the light receiving surface of the light receiving sensor 22 that receives the reflected light from the overlapping area 53 via the first lens element 251 is called a "first area 22A". Further, as shown in FIG. 16B, a region of the light receiving surface of the light receiving sensor 22 that receives reflected light from the overlapping area 53 via the second lens element 252 is called a "second region 22B". Reflected light from a certain point on the overlapping area 53 can be received by the pixels 221 on the first region 22A and the pixels 221 on the second region 22B of the light receiving sensor 22, respectively.

As shown in FIG. 3B, the overlapping area 53 (hatched area) is located in the center of the measurement area 50 in the Y direction. That is, as shown in FIG. 3B, reflected light from the central portion (overlapping area 53) of the measurement area 50 passes through the first lens element 251 and is received by the pixels 221 on the first region 22A of the light receiving sensor 22. and can be received by the pixels 221 on the second region 22B of the light receiving sensor 22 via the second lens element 252 .

As shown in FIG. 3C, when the measuring device 1 is mounted on a vehicle, it is desirable to measure the distance with a wide field of view in relatively close proximity. On the other hand, in the first embodiment, as shown in FIG. 3B, the aspect ratio of the measurement area 50 can be increased, which is advantageous for distance measurement in a wide field of view.
On the other hand, as shown in FIG. 3C, when the measuring device 1 is mounted on a vehicle, the area required to measure the distance to a long distance is allowed to be a relatively narrow range. It is assumed that the intensity of the light will become weaker. On the other hand, in the first embodiment, as shown in FIG. 3B, the reflected light from the overlapping area 53 of the measurement area 50 is applied to two pixels of the light receiving sensor 22 (pixels of each of the first region 22A and the second region 22B). 221), it is advantageous for measuring a long distance.

<Regarding the optical conditions of the light receiving unit 20>
18A and 18B are explanatory diagrams of the optical conditions of the light receiving section 20. FIG. FIG. 18A is an explanatory diagram of the relationship between the light receiving sensor 22 and the condenser lens 26. FIG. 18B is an explanatory diagram of the relationship between the virtual image 22′ of the light receiving sensor 22 and the coupling lens 25. FIG.

As shown in FIG. 18A, let the focal length of the condenser lens 26 be fB1. Also, let LB1 be the distance from the principal point of the condenser lens 26 to the light receiving sensor 22 . The half length of the light receiving sensor 22 in the Y direction is yB (the length from the optical axis of the light receiving optical system 24 to the end of the light receiving sensor 22 is yB).

In the first embodiment, the distance LB1 from the principal point of the condenser lens 26 to the light receiving sensor 22 is smaller than the focal length fB1 of the condenser lens 26 (LB1<fB1). Since the light-receiving sensor 22 is arranged closer than the focal point of the condenser lens 26 , the virtual image 22 ′ of the light-receiving sensor 22 (the image of the light-receiving sensor 22 by the condenser lens 26 ) is the image of the light-receiving sensor 22 when viewed from the condenser lens 26 . (left side of light receiving sensor 22 in the drawing).

Assuming that the distance from the principal point of the condensing lens 26 to the virtual image 22' is LB', the relationship between LB1, LB' and fB1 is given by the following equation (B1).
(1/LB1)-(1/LB')=1/fB1 (B1)

Therefore, the distance LB' from the principal point of the condenser lens 26 to the virtual image 22' is given by the following equation (B2).
LB'=(LB1×fB1)/(fB1-LB1) (B2)

Further, when the length from the optical axis of the light receiving optical system 24 to the edge of the virtual image 22' of the light receiving sensor 22 is yB', yB' is given by the following equation (B3).
yB'=yB*(LB'/LB1)
=yB×fB1/(fB1-LB1) (B3)

Next, let the focal length of the first lens element 251 and the second lens element 252 be fB2. As shown in FIG. 18B, let LB2 be the distance from the principal point of the coupling lens 25 (the principal point of the first lens element 251 or the second lens element 252) to the virtual image 22'. Here, as shown in FIG. 18B, considering that the coupling lens 25 forms an image of the reflected light from the distant irradiation area at the position of the virtual image 22', the relationship between the focal length fB2 and the distance LB2 is expressed by the following equation (B4 ).
LB2=fB2 (B4)

The distance between the principal point of the condensing lens 26 and the principal point of the coupling lens 25 is assumed to be dB. Here, since the distance LB2 corresponds to a value obtained by adding the distance dB to the distance LB', the relationship between the focal lengths fB1 and fB2 and each distance is expressed by the following equation (B5).
(LB1×fB1)/(fB1-LB1)+dB=fB2 (B5)

Further, as shown in FIG. 18B, the distance between the optical axis of the light-receiving optical system 24 (condensing lens 26) and the optical axis of the first lens element 251 (or the second lens element 252) is tB. tB”. Here, in order to form the overlapping area 53, the first measurement area 51 and the second measurement area 52 need to overlap. Therefore, the shift amount tB must be smaller than the length yB' from the optical axis of the light receiving optical system 24 to the edge of the virtual image 22' of the light receiving sensor 22 (tB<yB'). In other words, in order to form the overlapping area 53, the shift amount tB of each of the first lens element 251 and the second lens element 252 of the coupling lens 25 must satisfy the following equation (B6).
tB<yB×fB1/(fB1-LB1) (B6)

<Measurement example 3>
19A to 19C are explanatory diagrams of an example of the measurement method. On the right side of each area of the measurement area 50 in the drawing, the corresponding light emitting area of the light source 12 is shown. In addition, a region of the corresponding measurement area 50 is shown on the left side of each pixel 221 of the light receiving sensor 22 in the drawing.

The light source 12 is divided into a plurality of light-emitting regions in the Y direction, here 16 light-emitting regions (light-emitting regions #1 to #16). The number of light emitting regions of the light source 12 divided in the Y direction is not limited to 16. Each light emitting region (light emitting regions #1 to #16) of the light source 12 corresponds to each region of the measurement area 50 (region P to region A).

The control unit 30 controls the position on the measurement area 50 irradiated with light by causing a specific light emitting region out of the plurality of light emitting regions of the light source 12 to emit light. Here, the control unit 30 controls the light source 12 so as to emit light sequentially from the lowermost light emitting region #16 in the figure. As a result, areas A to P of the measurement area 50 are irradiated with light so as to scan. A case where a certain pixel of the light receiving sensor 22 can receive reflected light from two positions (first position and second position) of the measurement area 50 by scanning the light irradiated to the measurement area 50 in the Y direction. In addition, the two positions (the first position and the second position) can be prevented from being irradiated with light at the same time. Note that the control unit 30 does not have to cause the light emitting regions arranged in the Y direction to emit light in order. For example, the control unit 30 may control the position on the measurement area 50 to which light is emitted by causing the light emitting regions to emit light in random order. If light is not simultaneously applied to two positions (first position and second position) where a certain pixel of the light receiving sensor 22 can receive light, light may be applied to a plurality of areas of the measurement area 50 at the same time. . Further, by rotating the mirror, the areas A to P of the measurement area 50 may be scanned with light.

The timing chart of measurement example 3 is the same as the timing chart of measurement example 1 in FIG. However, in measurement example 1, light is emitted from the entire light emitting surface of light source 12, while in measurement example 3, a specific light emitting region out of a plurality of light emitting regions of light source 12 is caused to emit light. In Measurement Example 3, the timing (emission timing) at which the light emitting region of the light source 12 emits pulsed light is shown in the upper part of FIG. The center of FIG. 8 shows the timing (arrival timing) at which the pulsed reflected light arrives. Output signals of the pixels 221 (light receiving elements) are shown in the lower part of FIG.

The control unit 30 (timing control unit 34) causes the light source 12 to emit pulsed light at a predetermined cycle. After the pulsed light is emitted, the distance measurement section 36 (signal processing section 362) of the control section 30 detects the arrival timing of the reflected light based on the output signal of the pixel 221 (light receiving element). For example, the signal processing unit 362 detects the arrival timing of reflected light based on the peak timing of the output signal of each pixel 221 . The distance measurement unit 36 (time detection unit 364) of the control unit 30 detects the time Tf from when the light is emitted to when the reflected light arrives, based on the light emission timing and the light arrival timing. The time Tf corresponds to the time it takes the light to make a round trip between the measurement device 1 and the object 90 . Then, the distance measurement unit 36 (distance calculation unit 366) calculates the distance L to the object 90 based on the time Tf. When the time from irradiation of light to arrival of reflected light is Tf, and the speed of light is C, the distance L is L=C×Tf/2.

As shown in FIG. 19A, the light emitted from the light emitting region #16 of the light source 12 is irradiated to the region A of the measurement area 50 (first measurement area 51) via the light projecting optical system 14. As shown in FIG. The pixel #12 of the light receiving sensor 22 receives the reflected light from the area A via the light receiving optical system 24 (first lens element 251). The control unit 30 calculates the distance to the object 90 in the area A based on the output signal of the pixel #12 of the light receiving sensor 22. FIG.

After the light emission of the light emitting region #16 (in other words, after the measurement of the region A), the control unit 30 causes the light emitting regions #15 to #13 to emit light in order, and the light to the regions B to D of the first measurement area 51. The light is emitted in order, and the distances to the object 90 in the regions B to D are calculated in order based on the output signals of the pixels #11 to #9 of the light receiving sensor 22 .

As shown in FIG. 19B , the light emitted from the light emitting region #12 of the light source 12 is irradiated onto the region E of the measurement area 50 via the light projecting optical system 14 . Since the area E belongs to the overlapping area 53, the reflected light from the area E passes through the first lens element 251 and the second lens element 252 of the coupling lens 25 and is received by the pixels #8 and #12 of the light receiving sensor 22. It is possible.

The control unit 30 calculates the distance based on the output signal of the pixel #8 of the light receiving sensor 22, calculates the distance based on the output signal of the pixel #12 of the light receiving sensor 22, and calculates the average of the two calculated distances. The distance to the object 90 in the area E is calculated by obtaining the distance. This makes it possible to improve the accuracy of distance calculation and improve robustness. Further, the control unit 30 calculates the distance based on the output signal of the pixel #8 of the light receiving sensor 22, calculates the distance based on the output signal of the pixel #12 of the light receiving sensor 22, and calculates the distance between the two calculated distances. An abnormality may be detected when the difference is greater than a predetermined value. Note that the control unit 30 may calculate the distance to the object 90 in the area E based on the output signal of one of the pixels #8 and #12 of the light receiving sensor 22 .

After the light emission of the light emitting region #12 (in other words, after the measurement of the region E), the control unit 30 causes the light emitting regions #11 to #5 to emit light in order, and the regions F to L of the overlapping area 53 to emit light in order, Based on the output signals of the two pixels that received the reflected light, the distances to the object 90 in the regions F to L are calculated in order.

As shown in FIG. 19C, the light emitted from the light emitting region #4 of the light source 12 is irradiated onto the region M of the measurement area 50 (second measurement area 52) via the light projecting optical system 14. As shown in FIG. The pixel #4 of the light receiving sensor 22 receives the reflected light from the area M via the light receiving optical system 24 (second lens element 252). The control unit 30 calculates the distance to the object 90 within the area M based on the output signal of the pixel #4 of the light receiving sensor 22 . After the light emission of the light emitting region #4 (in other words, after the measurement of the region M), the control unit 30 sequentially causes the light emitting regions #3 to #1 to emit light, and sequentially irradiates the regions N to P of the second measurement area 52 with light. Then, based on the output signals of the pixels #3 to #1 of the light receiving sensor 22, the distances to the object 90 in the regions N to P are calculated in order.

According to the above measurement method, each of the 16 divided measurement areas 50 ( It is possible to calculate the distance to the object 90 within the regions A to P). Thus, the light receiving sensor 22 can receive reflected light over a wide range in the Y direction. For example, using a VGA (640×480 pixels) light receiving sensor 22 with 640 pixels arranged in the Y direction, it is possible to acquire an image (distance image) of the measurement area 50 with a resolution of 840 pixels in the Y direction. .

<Measurement example 4>
Another example of the light receiving sensor 22, shown in FIG. 9A, may be used. Even when each pixel 221 of the light receiving sensor 22 has a plurality of light receiving elements 222 as shown in FIG. 9A, the control unit 30 controls the light emission shown in FIG. The light source 12 is controlled so as to emit light sequentially from the area #16. As a result, areas A to P of the measurement area 50 are irradiated with light so as to scan.

First, as shown in FIG. 19A, the light emitted from the light emitting region #16 of the light source 12 is irradiated onto the region A of the measurement area 50 (first measurement area 51) via the light projecting optical system 14. , and the pixel #12 of the light receiving sensor 22 receives the reflected light from the area A via the light receiving optical system 24 (the first lens element 251), the method shown in FIGS. A distance to the object 90 is calculated.

Next, as shown in FIG. 19B, the light emitted from the light emitting region #12 of the light source 12 is irradiated onto the region E of the overlapping area 53 via the light projecting optical system 14, and is reflected from the region E. A case where light is received by the pixel #8 and the pixel #12 of the light receiving sensor 22 via the first lens element 251 and the second lens element 252 of the light receiving optical system 24 will be described.

FIG. 20 is an explanatory diagram of the signal processing unit 362 when measuring the overlapping area 53. FIG. The signal processor 362 has an adder 362A, a comparator 362B, a histogram generator 362C, and a histogram synthesizer 362D. Since the adding section 362A, the comparing section 362B, and the histogram generating section 362C have already been described, the description thereof will be omitted.

The histogram synthesizing unit 362D synthesizes the two histograms (single histograms) generated by the two histogram generating units 362C into one histogram (composite histogram). The histogram synthesizing unit 362D generates a synthesized histogram by synthesizing respective histograms (single histograms) based on two pixels associated with the overlap area 53 region. Here, the histogram combining unit 362D generates a combined histogram by combining two single histograms based on pixel #8 and pixel #12 of the light receiving sensor 22 corresponding to region E. FIG. Since a composite histogram is generated by combining two independent histograms, even if the number of times of accumulation of the independent histograms is half of the predetermined number, the histogram of the predetermined number of times of accumulation can be generated. Therefore, in the measurement of the overlapping area 53, a histogram of the set number of integrations can be generated at high speed, so distance measurement can be performed at high speed. Also, as shown in FIG. 3C, it is assumed that the intensity of the reflected light from the overlapping area 53 is weakened. ) and measure the distance to the object 90 based on the combined histogram, it is possible to suppress the deterioration of the distance measurement accuracy even if the intensity of the reflected light is weak.

FIG. 21 is an explanatory diagram of another signal processing section 362 when measuring the overlapping area 53. As shown in FIG.
The signal processor 362 has an adder 362A, a comparator 362B, and a histogram generator 362C. The adder 362A adds the output signals of the plurality of light receiving elements 222 (SPAD) forming the two pixels 221 (here, pixel #8 and pixel #12) associated with the overlapping area 53. FIG. That is, the adder 362A regards the two pixels 221 (here, the pixel #8 and the pixel #12) associated with the region of the overlap area 53 as substantially one pixel, and the plurality of light-receiving elements forming the pixel. The output signals of element 222 (SPAD) are summed. Compared with the adder 362A shown in FIG. 11B, the adder 362A shown in FIG. 21 adds twice as many output signals of the light receiving elements 222 (SPAD). The comparator 362B compares the output signal of the adder 362A with a threshold, and outputs a signal when the output signal of the adder 362A is greater than or equal to the threshold.

Note that the setting unit 32 (see FIG. 1) compares the threshold of the comparing unit 362B (see FIG. 9B) when measuring the measurement area 50 other than the overlapping area 53, and the comparing unit when measuring the overlapping area 53 362B (see FIG. 21) is set to a large value. This increases the probability that the light receiving element 222 (SPAD) of the light receiving sensor 22 has detected the reflected light when the output signal of the adder 362A is greater than or equal to the threshold. Since the number of output signals of the light-receiving element 222 (SPAD) added by the adder 362A is large, even if the threshold is set to a large value, the frequency of outputting the signal from the comparator 362B to the histogram generator 362C is reduced. No (predetermined number of times of histogram generation is not delayed). Therefore, it is allowed to set the threshold value of the comparison section 362B shown in FIG. 21 to a large value.

Based on the output of the comparison unit 362B, the histogram generation unit 362C repeatedly measures the time that the light receiving element 222 (SPAD) of the light receiving sensor 22 detects light, and increments the frequency (number of times) associated with that time. to generate a histogram. Note that compared to the signal processing unit 362 shown in FIG. 20, the signal processing unit 362 shown in FIG. can be reduced. In addition, as shown in FIG. 3C, it is assumed that the intensity of the reflected light from the overlapping area 53 is weakened. Since the light is received, even if the intensity of the reflected light is weak, the deterioration of distance measurement accuracy can be suppressed.

=== Summary 1 ===
The measuring apparatus 1 described above includes a light source 12 , a light projecting optical system 14 that irradiates a measurement area 50 with light from the light source 12 , and a light receiving section 20 that receives reflected light from the measurement area 50 . The light projecting optical system 14 has a connecting lens 15 in which the first lens element 151 and the second lens element 152 are connected. The optical axis of the first lens element 151 is shifted in the +Y direction (corresponding to the first direction), and the optical axis of the second lens element 152 is shifted in the -Y direction (the direction in which the optical axis of the first lens element 151 is shifted). and vice versa). Light from the light source 12 irradiates the first measurement area 51 through the first lens element 151 and irradiates the second measurement area 52 including the overlapping area 53 through the second lens element 152 . According to such a measuring device 1, a wide range in the Y direction (corresponding to the first direction) can be irradiated with light. In addition, since the overlapping area 53 is provided, it is possible to prevent the formation of an area that cannot be irradiated with light between the first measurement area 51 and the second measurement area 52 .

In the measuring apparatus 1 described above, the ratio of the length of the measurement area 50 in the Y direction (corresponding to the first direction) to the length of the X direction (corresponding to the second direction) is the same as that of the light source 12 in the X direction (corresponding to the second is greater than the ratio of the length in the Y direction (corresponding to the first direction) to the length in the Y direction (corresponding to the first direction) (see FIGS. 3A and 3B). Thereby, the angle of view of the measurement area 50 in the Y direction can be widened.

In addition, in the measuring apparatus 1 described above, the first area 121 and the second area 122 of the light source 12 are caused to emit light at the same time, so that the light projecting optical system 14 transmits the light of the first area 121 of the light source 12 to the first lens. The overlapping area 53 is illuminated through the element 151 , and the light from the second region 122 of the light source 12 is illuminated through the second lens element 152 onto the overlapping area 53 . This makes it possible to increase the intensity of the light that irradiates the overlapping area 53 (the hatched area in FIG. 3B) of the measurement area 50 .

The projection optical system 14 has a projection lens 16 between the light source 12 and the coupling lens 15 . Having the projection lens 16 in the projection optical system 14 makes it possible to project the light from the light source 12 over a wide range. However, the projection optical system 14 may not have the projection lens 16 (in this case, the virtual image 12' in FIG. 6B is replaced with the light source 12, so the light source 12 and the measuring device 1 are enlarged. ).

In the projection optical system 14, the focal length of the projection lens 16 is fA1, the distance from the principal point of the projection lens 16 to the light source 12 is LA1, and the width of the light source 12 in the Y direction (corresponding to the first direction) is , and tA is the distance (shift amount) between the optical axis of the projection optical system 14 and the optical axis of the first lens element 151 in the Y direction, tA<yA×fA1/( fA1-LA1) is desirable. Thereby, an overlapping area 53 can be provided in the measurement area 50 .

The control unit 30 of the measuring device 1 described above calculates the distance to the object 90 from which the reflected light is reflected, based on the arrival time from when the light source 12 emits light until when the reflected light is received. However, the measuring device 1 is not limited to measuring the distance to the object 90 . For example, without calculating the distance, the measuring device 1 may measure the arrival time from when the light source 12 emits light until when the reflected light is received. may be used to measure

The control unit 30 of the measuring device 1 described above generates a histogram by repeatedly measuring the time that the light receiving element 222 of the light receiving unit 20 detects light, and detects the light arrival time Tf based on the peak of the histogram. When detecting the arrival time Tf of light using the histogram in this way, it is particularly effective to increase the intensity of light in the overlapping area 53 of the measurement area 50 using the coupling lens 15 of the first embodiment.

=== Summary 2 ===
The measurement apparatus 1 described above includes an irradiation section 10 that irradiates a measurement area 50 with light, a light receiving sensor 22 , and a light receiving optical system 24 that causes the light receiving sensor 22 to receive the reflected light from the measurement area 50 . The light-receiving optical system 24 has a connecting lens 25 connecting the first lens element 251 and the second lens element 252 . The optical axis of the first lens element 251 is shifted in the +Y direction (corresponding to the first direction), and the optical axis of the second lens element 252 is shifted in the -Y direction (the direction in which the optical axis of the first lens element 251 is shifted). and vice versa). Reflected light from the first measurement area 51 of the measurement area 50 is received by the light receiving element of the light receiving sensor 22 via the first lens element 251 . Reflected light from the second measurement area 52 including the overlapping area 53 is received by the light receiving element of the light receiving sensor 22 via the second lens element 252 . According to such a measuring device 1, it is possible to receive reflected light from a wide range in the Y direction (corresponding to the first direction). Moreover, since the overlapping area 53 is provided, it is possible to prevent the formation of an area that cannot receive the reflected light between the first measurement area 51 and the second measurement area 52 .

The control unit 30 described above controls the position on the measurement area 50 where the light is irradiated. As a result, it is possible to irradiate a predetermined position on the measurement area 50 with light or not to irradiate a predetermined position on the measurement area 50 with light.

A certain pixel of the light receiving sensor 22 (for example, pixel #5 shown in FIGS. 17A and 17B) receives reflections from two positions (first position and second position; for example, region H and region L) of the measurement area 50. It can receive light. In such a case, the control unit 30 controls the first position (for example, region H) of the first measurement area 51 and the second position (for example, region L) of the second measurement area 52 where the pixel (for example, pixel #5) can receive light. ), the irradiation unit 10 is controlled so as not to irradiate both regions with light at the same time. This makes it possible to determine from which of the two positions on the measurement area 50 the reflected light is received when the light-receiving element of that pixel receives the reflected light.

As shown in FIG. 19B, the reflected light from the region E (predetermined position) of the overlapping area 53 can be received by the light receiving element (first light receiving element) of the pixel #8 of the light receiving sensor 22 via the first lens element 251. In addition, the light can be received by the light receiving element (second light receiving element) of the pixel #12 of the light receiving sensor 22 via the second lens element 252 . Robustness can be improved by enabling two light receiving elements to receive reflected light from the same position in this way.

Further, when light is applied to the region E (predetermined position) of the overlapping area 53, the control unit 30 controls the output signal (first light receiving result) of the light receiving element of the pixel #8 of the light receiving sensor 22 and the light receiving of the pixel #12. An output signal (second light receiving result) of the element is acquired. Robustness can be improved by acquiring the output signals (light receiving results) of the two light receiving elements that receive the reflected light from the same position in this way.

Further, the control unit 30 calculates the distance to the object 90 in the area E based on the output signal (first light receiving result) of the light receiving element of the pixel #8 of the light receiving sensor 22, and calculates the distance to the object 90 in the area E. The distance to the object 90 in the same area E is calculated based on the output signal (second light reception result) of the. Robustness can be improved by calculating the distance based on the output signals (light receiving results) of the two light receiving elements that received the reflected light from the same position.

Further, the control unit 30 calculates the distance calculated based on the output signal (first light receiving result) of the pixel #8 of the light receiving sensor 22 and the distance calculated based on the output signal (second light receiving result) of the pixel #12. Anomalies may be detected based on the distance. With this, it is possible to determine any malfunction of the measuring device 1 .

As shown in FIG. 20, the control unit 30 generates a single histogram (first histogram) by repeatedly measuring the time when the light receiving element (first light receiving element) of pixel #8 of the light receiving sensor 22 detects light. A single histogram (second histogram) is generated by repeatedly measuring the time during which the light receiving element (second light receiving element) of pixel #12 detects light, and a combined histogram (third histogram) is obtained by synthesizing the two single histograms. may be generated. In this case, the control unit 30 can detect the light arrival time Tf (see FIG. 9C) based on the peak of the composite histogram (third histogram), and the distance to the object can be detected based on the detected arrival time Tf. Calculate As a result, even if the number of integrations of the independent histograms (the first histogram and the second histogram) is half of the predetermined number, it is possible to generate a composite histogram (the third histogram) with the predetermined number of integrations. can be performed at high speed.

As shown in FIG. 21, the control unit 30 controls the time when the light receiving element (first light receiving element) of the pixel #8 of the light receiving sensor 22 detects light and the time when the pixel #12 (second light receiving element) detects light. A histogram may be generated by repeatedly measuring time. As a result, it is possible to reduce the capacity of the memory for storing the data for generating the histogram, and reduce the amount of calculation for generating the histogram. Also in this case, the control unit 30 can detect the light arrival time Tf (see FIG. 9C) based on the peak of the histogram, and calculate the distance to the object based on the detected arrival time Tf. will do.

The light-receiving optical system 24 described above has a condenser lens 26 between the light-receiving sensor 22 and the coupling lens 25 . Since the light-receiving optical system 24 has the condenser lens 26, it becomes possible for the light-receiving sensor 22 to receive reflected light from a wide range. However, the light-receiving optical system 24 may not have the condenser lens 26 (in this case, the light-receiving sensor 22 having a light-receiving surface of the size of the virtual image 22' in FIG. 18B is substituted. 22 and the measuring device 1 are enlarged).

In the light-receiving optical system 24, the focal length of the condenser lens 26 is fB1, the distance from the principal point of the condenser lens 26 to the light-receiving sensor 22 is LB1, and the light-receiving sensor in the Y direction (corresponding to the first direction) 22, and tB is the distance (shift amount) between the optical axis of the light receiving optical system 24 and the optical axis of the first lens element 251 in the Y direction. /(fB1-LB1) is desirable. Thereby, an overlapping area 53 can be provided in the measurement area 50 .

Although the embodiments of the present disclosure have been described in detail above, the present disclosure is not limited to the above embodiments, and includes various modifications. In addition, the above-described embodiment describes the configuration in detail in order to explain the present disclosure in an easy-to-understand manner, and is not necessarily limited to those having all the described configurations. Moreover, it is possible to add, delete, or replace a part of the configuration of the above embodiment with another configuration.

This application claims priority based on Japanese Application No. 2022-018941 filed on February 9, 2022 and Japanese Application No. 2022-018942 filed on February 9, 2022, and described in the Japanese application All description contents are used.

Claims

a light source;
a light projecting optical system for irradiating a measurement area with light from the light source;
a light receiving unit that receives reflected light from the measurement area,
The light projecting optical system includes:
a connecting lens connecting a first lens element whose optical axis is shifted in a first direction and a second lens element whose optical axis is shifted in a direction opposite to the first lens element;
irradiating a first measurement area with light from the light source through the first lens element;
A measurement apparatus for irradiating light from the light source through the second lens element onto a second measurement area including an overlapping area that overlaps the first measurement area.
The measuring device according to claim 1,
The ratio of the length of the measurement area in the first direction to the length of the second direction perpendicular to the optical axis and the first direction is the length of the light source in the first direction to the length of the light source in the second direction. A measuring device that is greater than a fraction of the length of the
The measuring device according to claim 1 or 2,
By simultaneously causing the first region and the second region of the light source to emit light, the light projecting optical system
irradiating the overlapping area with the light of the first region through the first lens element;
A measuring device that irradiates the overlapping area with the light of the second region through the second lens element.
The measuring device according to any one of claims 1 to 3,
The measuring device, wherein the projection optical system has a projection lens between the light source and the coupling lens.
The measuring device according to claim 4,
the focal length of the projection lens is fA1;
LA1 is the distance from the principal point of the projection lens to the light source,
yA the half length of the width of the light source in the first direction,
When the distance between the optical axis of the light projecting optical system and the optical axis of the first lens element in the first direction is tA,
A measuring device wherein tA<yA×fA1/(fA1−LA1).
The measuring device according to any one of claims 1 to 5,
A measuring apparatus comprising a controller that calculates a distance to an object that reflects the reflected light based on an arrival time from when the light source emits light to when the reflected light is received.
The measuring device according to claim 6,
The control unit
generating a histogram by repeatedly measuring the time that the light receiving element of the light receiving unit detects light;
A measuring device that detects the arrival time based on the peak of the histogram.
an irradiation unit that irradiates a measurement area with light;
a light receiving sensor;
a light-receiving optical system for causing the light-receiving sensor to receive the reflected light from the measurement area,
The light-receiving optical system is
a connecting lens connecting a first lens element whose optical axis is shifted in a first direction and a second lens element whose optical axis is shifted in a direction opposite to the first lens element;
causing the light receiving element of the light receiving sensor to receive the reflected light from the first measurement area via the first lens element;
A measurement apparatus, wherein the light receiving element receives the reflected light from a second measurement area including an overlapping area that overlaps the first measurement area via the second lens element.
The measuring device according to claim 8,
A measuring apparatus comprising a control unit that controls a position on the measurement area where the irradiation unit irradiates the light.
The measuring device according to claim 9,
When the light-receiving element of the light-receiving sensor can receive reflected light from a first position in the first measurement area and reflected light from a second position in the second measurement area, the controller controls the A measuring device that controls the irradiation unit so that the first position and the second position are not irradiated with the light at the same time.
The measuring device according to claim 8,
The light receiving sensor has a first light receiving element and a second light receiving element,
The first light receiving element is capable of receiving reflected light from a predetermined position on the measurement area via the first lens element,
The measuring device, wherein the second light receiving element can receive reflected light from the predetermined position on the measurement area via the second lens element.
The measuring device according to claim 9 or 10,
The light receiving sensor has a first light receiving element and a second light receiving element,
The first light receiving element is capable of receiving reflected light from a predetermined position on the measurement area via the first lens element,
The measuring device, wherein the second light receiving element can receive reflected light from the predetermined position on the measurement area via the second lens element.
The measuring device according to claim 11,
A measuring apparatus comprising a control unit that acquires a first light receiving result of the first light receiving element and a second light receiving result of the second light receiving element.
13. The measuring device according to claim 12,
The measuring device, wherein the control unit acquires a first light receiving result of the first light receiving element and a second light receiving result of the second light receiving element.
15. The measuring device according to claim 13 or 14,
The control unit
Based on the first light receiving result, calculating the distance to the object at the predetermined position,
A measuring device that calculates a distance to an object at the predetermined position based on the result of the second light reception.
16. The measuring device according to claim 15,
The measuring device, wherein the control unit detects an abnormality based on the distance calculated based on the first light reception result and the distance calculated based on the second light reception result.
15. The measuring device according to claim 13 or 14,
The control unit
generating a first histogram by repeatedly measuring the time that the first light receiving element detects light;
generating a second histogram by repeatedly measuring the time that the second light receiving element detects light;
generating a third histogram that is a combination of the first histogram and the second histogram;
A measuring device that calculates the distance to the object at the predetermined position by detecting the arrival time from emitting light to receiving the reflected light based on the peak of the third histogram.
15. The measuring device according to claim 13 or 14,
The control unit
generating a histogram by repeatedly measuring the time when the first light receiving element detects light and the time when the second light receiving element detects light;
A measuring device that calculates the distance to the object at the predetermined position by detecting the arrival time from emitting light to receiving the reflected light based on the peak of the histogram.
The measuring device according to any one of claims 8 to 18,
The measuring device, wherein the light receiving optical system has a condenser lens between the light receiving sensor and the coupling lens.
20. A measuring device according to claim 19,
the focal length of the condenser lens is fB1;
LB1 is the distance from the principal point of the condenser lens to the light receiving sensor;
yB is half the width of the light receiving sensor in the first direction;
When the distance between the optical axis of the light-receiving optical system and the optical axis of the first lens element in the first direction is tB,
A measuring device wherein tB<yB×fB1/(fB1−LB1).