Light-emitting device and distance measuring device

Abstract

To suppress the optical amount radiated to a target object having entered an overlapping region from becoming excessive more than when a part of light sources radiating light beams on the same region is turned off.SOLUTION: A light-emitting device includes: a light-emitting unit for radiating light beams from a plurality of light sources to different radiation regions in parallel; and a control unit for turning off a part of the light sources for radiating light beams on an overlapping region where the radiation regions for the light sources overlap with one another in a case where entrance of a target object into the overlapping region is detected.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a light-emitting device and a distance measuring device.

Background Art

[0002] Patent Document 1 describes a distance measuring device that pre-emits light from a light source, controls the emission amount of main emission based on the received light amount for each light receiving region, and measures the distance to a distance measurement target. Patent Document 2 describes a three-dimensional measurement device that includes a human sensor for detecting a person and controls the output of laser light according to whether information indicating that there is no person within the detection range is received.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0004] There is a distance measuring device that measures the distance to an object (referred to as "distance measurement") by the so-called time-of-flight (TOF) method that measures the time from the emission of light to the reception of the light reflected by the object. In such a distance measuring device, by irradiating different regions with a plurality of light sources, a wider region can be measured compared to the case of a single light source. However, when irradiating light rays from a plurality of light sources in parallel to different irradiation regions, overlapping of the irradiation regions may occur depending on the distance from the light sources. Since the light amount increases in the overlapping region where the irradiation regions overlap, when an object enters the overlapping region, the light amount irradiated to the object becomes excessive. The object of the present invention is to suppress an excessive amount of light irradiated onto an object that has entered an overlapping region, as compared with a case where a part of a plurality of light sources that irradiate light rays with overlapping irradiation regions is not turned off.

Means for Solving the Problems

[0005] The invention according to claim 1 is a light-emitting device including a light-emitting unit that irradiates light rays from a plurality of light sources in parallel onto different irradiation regions, and a control unit that turns off a part of the plurality of light sources that irradiate light rays onto an overlapping region when an entry of an object into the overlapping region where the irradiation regions by the respective light sources overlap is detected. The invention according to claim 2 is the light-emitting device according to claim 1, wherein the light-emitting unit is arranged such that the overlapping region extends in a direction intersecting the entry direction of the object. The invention according to claim 3 is the light-emitting device according to claim 2, wherein the control unit determines the part of the plurality of light sources to be turned off according to the entry direction of the object. The invention according to claim 4 is the light-emitting device according to claim 1, wherein each of the plurality of light sources has a plurality of light-emitting sections, and the control unit determines a portion to be turned off from among the plurality of light-emitting sections. The invention according to claim 5 is a distance measuring device including the light-emitting device according to claim 1, a light-receiving unit that receives light rays emitted from the light-emitting unit and reflected by an object, and a distance measuring unit that measures a distance to the object based on a result of light reception by the light-receiving unit. The invention according to claim 6 is the distance measuring device according to claim 5, wherein the control unit turns off a part of the light sources based on a result of light reception by the light-receiving unit. The invention according to claim 7 is the distance measuring device according to claim 6, wherein the control unit detects an entry of an object into the overlapping region based on a result of light reception by the light-receiving unit, and turns off the light when a light reception amount by the light-receiving unit exceeds a predetermined value. The invention according to claim 8 is the distance measuring device according to claim 6, wherein the control unit turns off the light when a distance to the object is closer than a predetermined distance. The invention according to claim 9 is such that each of the plurality of light sources has a plurality of light-emitting sections, and when the control unit detects the entry of a second object into the overlapping region that satisfies a predetermined requirement while a first object exists in the irradiation region, a part of the plurality of light-emitting sections is turned off so as to eliminate the overlap of the overlapping region into which the second object has entered while maintaining the irradiation of the first object. The light-emitting device according to claim 1. The invention according to claim 10 is such that when the control unit detects the entry of an object into the overlapping region, the plurality of light sources that irradiate the overlapping region are sequentially turned on while eliminating the overlap of the overlapping region. The light-emitting device according to claim 1. The invention according to claim 11 is such that after the distance measuring unit sequentially turns on the plurality of light sources that irradiate light rays into the overlapping region, the distance to the object is measured based on the result of the light reception by the light receiving unit during the period when the light sources are sequentially turned on. The distance measuring device according to claim 5.

Advantages of the Invention

[0006] According to the inventions of claims 1 and 5, it is possible to suppress the amount of light irradiated to an object that has entered the overlapping region from becoming excessive as compared with the case where a part of the plurality of light sources that irradiate light rays causing an overlap in the irradiation region is not turned off. According to the invention of claim 2, it is possible to eliminate the overlap of the overlapping region before an object enters the overlapping region. According to the invention of claim 3, it is possible to eliminate the overlap of the overlapping region while maintaining the state of irradiating the object. According to the invention of claim 4, it is possible to more finely eliminate the overlap of the overlapping region as compared with the case where the plurality of light-emitting sections are not provided. According to the invention of claim 6, it is possible to suppress the amount of light irradiated to an object that has entered the overlapping region from becoming excessive based on the light reception result. According to the invention of claim 7, it is possible to eliminate the state where the amount of light received by the light receiving unit is excessive. According to the invention of claim 8, it is possible to eliminate a state in which the amount of light irradiated to the object becomes excessive when the object enters an overlapping area closer than a predetermined distance. According to the invention of claim 9, when there are a plurality of objects and one object enters an overlapping area that satisfies a predetermined requirement, it is possible to eliminate the overlap of the overlapping area entered by one object while maintaining the irradiation to the other objects. According to the invention of claim 10, it is possible to irradiate the entire irradiation area without omission while eliminating the overlap of the overlapping area entered by the object. According to the invention of claim 11, it is possible to measure the distance to the object existing in the entire irradiation area without omission while eliminating the overlap of the overlapping area entered by the object.

Brief Description of the Drawings

[0007]

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Embodiments for Carrying Out the Invention

[0008] Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. <First Embodiment> (Distance Measuring Device 1) FIG. 1 is a block diagram showing an example of the schematic configuration of a distance measuring device 1 to which the first embodiment is applied. The distance measuring device 1 measures the distance to an object based on the result of receiving the light emitted from the light emitting unit 4 described later and reflected by the object with the light receiving unit 5 described later. The distance measuring device 1 measures, for example, the distance from the distance measuring device 1 to the object based on the ToF (Time of Flight) method. Incidentally, the distance measuring device 1 measures the distance to the object based on the time from the timing when the light is emitted from the light emitting unit 4 to the timing when the emitted light is reflected by the object and received by the light receiving unit 5. The ToF method includes an indirect ToF (iToF: indirect ToF) method of measuring time from the difference between the phase of the emitted light and the phase of the received light, and a direct ToF (dToF: direct ToF) method of directly measuring the time from the emission to the reception of the light. Here, without distinguishing between the indirect ToF method and the direct ToF method, it will be described as the ToF method.

[0009] As shown in FIG. 1, the distance measuring device 1 includes an optical device 3 and a control unit 8. The optical device 3 includes a light emitting unit 4 that emits light toward a predetermined irradiation range, a light receiving unit 5 that receives the light emitted from the light emitting unit 4 and reflected by an object existing in the irradiation range, a light emitting drive unit 6 that drives the light emitting unit 4, and a light receiving drive unit 7 that drives the light receiving unit 5.

[0010] The control unit 8 controls the operations of the light emitting unit 4 and the light receiving unit 5 of the optical device 3. Further, the control unit 8 acquires the result of light reception in the light receiving unit 5, and measures the distance from the distance measuring device 1 to the object by the ToF method based on this result of light reception. The control unit 8 is an example of a distance measuring unit.

[0011] (Light emitting unit 4) The light emitting unit 4 includes a plurality of light sources each having a light emitting surface in which a plurality of vertical cavity surface emitting lasers VCSEL (Vertical Cavity Surface Emitting Laser, hereinafter referred to as "VCSEL") are arranged. The VCSEL is an example of a light emitting element. The light emitting unit 4 irradiates light rays from a plurality of light sources in parallel to different irradiation regions. The light rays emitted from each light source are diffused by a diffusion unit (not shown) onto a plane perpendicular to the emission direction and then irradiated. As the diffusion unit, a diffusion plate provided on the optical path of light and diffusing light by scattering or the like, a diffractive optical element (DOE: Diffractive Optical Element) that changes the angle of incident light and emits it, or / and an optical member such as a lens can be used. The light rays from the plurality of light sources of the light emitting unit 4 may be irradiated in parallel or may be irradiated so as to intersect. Depending on the distance from the light sources, the irradiation regions of the light rays from the plurality of light sources may overlap. The overlap of the irradiation regions will be described with reference to FIG. 2.

[0012] FIG. 2 is a diagram for explaining the relationship between the light emitting unit 4 according to the first embodiment and the irradiation regions irradiated with light from the light emitting unit 4. FIG. 2 shows an example in which the light emitting unit 4 includes two light sources, light source A1 and light source A2, and the light rays from light source A1 and light source A2 are irradiated so as to intersect. In FIG. 2, the left direction with respect to the direction in which the light emitting unit 4 irradiates light rays is defined as the x direction, the upward direction on the paper surface is defined as the y direction, and the direction in which the light emitting unit 4 irradiates light rays is defined as the z direction. In FIG. 2, light source A1 is arranged in the upward direction on the paper surface (+y direction) with respect to light source A2.

[0013] Each of the light sources A1 and A2 is independently driven to emit light by a light emission driving unit 6 (see FIG. 1). Driving of the light sources A1 and A2 means that power is supplied to the VCSELs included in the light sources A1 and A2 to emit light. Also, "independently driven" means that the light sources A1 and A2 are each driven to emit light. The light emission driving unit 6 drives each of the light sources A1 and A2 according to a control signal from a control unit 8 (see FIG. 1). Therefore, in the example of FIG. 2, the light sources A1 and A2 do not necessarily emit light at the same time, and for example, a state where light source A1 is emitting light but light source A2 is not emitting light can be taken.

[0014] The irradiation regions irradiated with the light rays from the light sources A1 and A2 may have an overlapping region where the irradiation regions overlap, depending on the distance from the light sources. The irradiation surfaces 210 and 220 are surfaces that are irradiated with light from the light emitting unit 4 and are orthogonal to the direction in which light is emitted from the light emitting unit 4 at a certain distance in the direction in which light is emitted within the irradiation region. In FIG. 2, the irradiation surface 220 is located in the direction away from the light emitting unit 4 (+z direction) with respect to the irradiation surface 210.

[0015] The irradiation surface 210 is formed by an irradiation surface B1 irradiated with light rays from the light source A1 and an irradiation surface B2 irradiated with light rays from the light source A2. When the light rays from the light sources A1 and A2 are irradiated so as to intersect, while the light sources A1 and A2 are positioned in this order in the -y direction, the irradiation surfaces B1 and B2 are positioned in this order in the +y direction. A partial region in the y direction of the irradiation surface B1 and the irradiation surface B2 overlaps, and an overlapping region D1 is formed. The irradiation surface 220 is formed by an irradiation surface C1 irradiated with light rays from the light source A1 and an irradiation surface C2 irradiated with light rays from the light source A2. When the light rays from the light sources A1 and A2 are irradiated so as to intersect, while the light sources A1 and A2 are positioned in this order in the -y direction, the irradiation surfaces C1 and C2 are positioned in this order in the +y direction. A partial region in the y direction of the irradiation surface C1 and the irradiation surface C2 overlaps, and an overlapping region D2 is formed.

[0016] When the light rays from the light sources A1 and A2 are irradiated so as to intersect, the width in the y direction of the overlapping region where the irradiation regions overlap becomes narrower as the distance from the light emitting unit 4 increases. At a position further away from the light emitting unit 4 than the irradiation surface 220, the width of the overlapping region becomes even narrower, and at a certain distance, the overlapping region is no longer formed.

[0017] FIG. 3 is a diagram for explaining the relationship between the light-emitting unit 4 according to the first embodiment and the irradiation surfaces 210 and 220 irradiated with the light emitted from the light-emitting unit 4. In FIG. 3, the left direction of the paper surface is the x direction, the upper direction of the paper surface is the y direction, and the back side direction of the paper surface is the z direction. In FIG. 3, the light-emitting unit 4 and the irradiation surfaces 210 and 220 are shown shifted in the vertical direction (±y direction) of the paper surface, but the light-emitting unit 4 and the irradiation surfaces 210 and 220 are positioned to face each other. In FIG. 3, the light-emitting unit 4 is located in the front side direction (-z direction) of the paper surface, the irradiation surface 210 is located in the back side direction (+z direction) of the paper surface, and the irradiation surface 220 is located further in the back side direction (+z direction). The irradiation surface 220 is located in a direction (+z direction) away from the light-emitting unit 4 with respect to the irradiation surface 210, and the overlapping region D2 formed on the irradiation surface 220 has a narrower width in the y direction than the overlapping region D1 formed on the irradiation surface 210.

[0018] (Light-receiving unit 5) The light-receiving unit 5 has a light-receiving surface that extends in the x direction and the y direction and on which a plurality of light-receiving elements are arranged. Then, the light-receiving unit 5 receives, by each light-receiving element, the light emitted from the light-emitting unit 4 and reflected by an object present in the irradiation region. The light-receiving surface is divided into a plurality of light-receiving sections corresponding to the plurality of light sources of the light-emitting unit 4. When the light-emitting unit 4 has two light sources A1 and A2 as shown in FIG. 2, the light-receiving surface is divided into two light-receiving sections in the y direction. Each light-receiving section has a plurality of light-receiving elements arranged regularly. Each light-receiving element receives the light emitted from the light-emitting unit 4 and reflected by an object present in the irradiation region, and outputs an electrical signal according to the received light. Examples of the light-receiving element include a photodiode and a phototransistor.

[0019] Each light-receiving section is independently driven by a light-receiving driving unit 7 (see FIG. 1) to perform a light-receiving operation. Driving the light-receiving section means changing the light-receiving elements included in the light-receiving section from a state where they cannot receive light to a state where they can receive light and output an electrical signal. Also, "independently driven" means being driven for each light-receiving section to a state where it can receive light and output an electrical signal. The light-receiving driving unit 7 drives each light-receiving section in response to a control signal from a control unit 8 (see FIG. 1). Then, when the light-receiving elements included in each light-receiving section receive light, they output an electrical signal corresponding to the received light to the control unit 8.

[0020] (Control unit 8) Returning to FIG. 1, the control unit 8 is composed of a CPU (Central Processing Unit) 81, a ROM (Read Only Memory) 82, and a RAM (Random Access Memory) 83. The CPU 81 is an example of a processor, and realizes various functions described later by loading and executing various programs stored in the ROM 82 etc. into the RAM 83. The RAM 83 is a memory used as a working memory etc. of the CPU 81. The ROM 82 is a memory that stores various programs etc. executed by the CPU 81.

[0021] Here, the program executed by the CPU 81 can be provided in a state stored in a computer-readable recording medium such as a magnetic recording medium (magnetic tape, magnetic disk, etc.), an optical recording medium (optical disk, etc.), a magneto-optical recording medium, or a semiconductor memory. Also, the program executed by the CPU 81 may be provided using a communication means such as the Internet.

[0022] In addition, in the first embodiment, the processor refers to a processor in a broad sense, including a general-purpose processor (e.g., CPU: Central Processing Unit, etc.) and a dedicated processor (e.g., GPU: Graphics Processing Unit, ASIC: Application Specific Integrated Circuit, FPGA: Field Programmable Gate Array, programmable logic device, etc.). Also, the operation of the processor in the first embodiment may be achieved not only by one processor but also by a plurality of physically separated processors cooperating with each other. Also, the order of each operation of the processor is not limited to only the order described in the first embodiment and may be changed.

[0023] The control unit 8 controls the operation of the light-emitting unit 4 through the light-emitting drive unit 6 and controls the operation of the light-receiving unit 5 through the light-receiving drive unit 7. The control unit 8 acquires the electrical signal output from the light-receiving element of the light-receiving unit 5. Then, the control unit 8 creates a distance image representing the distance between the distance measuring device 1 and the object based on the electrical signal acquired from the light-receiving element using the above-described ToF method. Additionally, the control unit 8 calculates the distance between the distance measuring device 1 and the object by performing predetermined arithmetic processing on the electrical signal acquired from the light-receiving element of the light-receiving unit 5 and creates a distance image.

[0024] (Operation control of the light-emitting unit 4) An example of the control of the operation of the light-emitting unit 4 by the control unit 8 will be described using the example shown in FIG. 2. As shown in FIG. 2, the irradiation regions irradiated with the light rays from the light sources A1 and A2 have an overlapping region where the irradiation regions overlap according to the distance from the light sources. For example, an overlapping region D1 is formed on the irradiation surface 210, and the overlapping region D1 is a region where the amount of irradiated light increases. If an object exists in the overlapping region D1, the amount of light irradiated to the object may become excessive, and problems may occur.

[0025] For example, in a light receiving element that receives light reflected by an object existing in the overlapping region D1, signal saturation may occur, which may cause an obstacle to measurement. In addition, there may also be a problem caused by the concentration of the light amount. When an object exists in the overlapping region where such a problem may occur, the control unit 8 turns off some of the plurality of light sources of the light emitting unit 4 to eliminate the overlap of the overlapping region. In the example shown in FIG. 2, the control unit 8 eliminates the overlap of the overlapping region by turning off the light source A1, for example.

[0026] Further, the control unit 8 may be configured not to perform control to turn off some of the light sources even when an object exists in the overlapping region and no problem occurs. The case where no problem occurs is, for example, when the distance between the overlapping region where the object has entered and the light source is far, and the amount of light irradiated on the object does not become excessive. When the control unit 8 detects the entry of an object into the overlapping region, it determines whether the overlapping region satisfies a predetermined requirement. The predetermined requirement is a criterion for whether a problem occurs when an object enters the overlapping region. When the overlapping region satisfies the predetermined requirement, the control unit 8 turns off some of the plurality of light sources of the light emitting unit 4 to eliminate the overlap of the overlapping region. Here, "detecting entry" includes "detecting that entry has occurred" and "detecting that entry will occur in the future".

[0027] The control unit 8 detects the entry of an object into the overlapping region based on the result of light reception by the light receiving unit 5, and determines whether the overlapping region where the object has entered satisfies a predetermined requirement. The predetermined requirement is determined, for example, with respect to the amount of light received by the light receiving unit 5 and the distance between the entered object and the light emitting unit 4. When determining whether the predetermined requirement is satisfied based on the amount of light received by the light receiving unit 5, it is determined whether the amount of light received exceeds a threshold value at which signal saturation occurs in the light receiving unit 5. When the amount of light received exceeds the threshold value, the control unit 8 turns off some of the plurality of light sources. Note that the threshold value is a predetermined value that can be freely set, and it is possible to set a threshold value at which a problem may occur, not limited to the case where signal saturation occurs.

[0028] When determining whether to meet the requirements predetermined based on the distance between the entered object and the light emitting unit 4, the control unit 8 measures the distance to the object based on the result of light reception by the light receiving unit 5, and determines whether it is closer than the predetermined distance. When the distance between the object and the light emitting unit 4 is closer than the predetermined distance, the control unit 8 turns off a part of the plurality of light sources. For example, in FIG. 2, assume that the overlapping region D1 of the irradiation surface 210 is a region that meets the predetermined requirements, and the overlapping region D2 of the irradiation surface 220 is a region that does not meet the predetermined requirements. In this case, when an object enters the overlapping region D1, the control unit 8 turns off either the light source A1 or A2 to eliminate the overlap of the overlapping region. On the other hand, even when an object enters the overlapping region D2, the control unit 8 does not perform the turn-off control.

[0029] When performing the turn-off control after detecting that an object has entered the overlapping region where a problem may occur, the object will be temporarily irradiated with light that may cause a problem. For example, when the object is conveyed by a belt conveyor and the entry direction of the object is constant, by arranging the light emitting unit 4 so that the overlapping region extends in a direction intersecting the entry direction of the object, it is possible to detect the entry before the object enters the overlapping region. FIG. 4 is a diagram for explaining the relationship between the light emitting unit 4 when a plurality of light sources are arranged so that the overlapping region extends in a direction intersecting the entry direction of the object, and the irradiation surfaces 210 and 220 irradiated with the light emitted from the light emitting unit 4. In FIG. 4, similar to FIG. 2, the left direction with respect to the direction in which the light emitting unit 4 irradiates the light beam is defined as the x direction, the upward direction on the paper surface is defined as the y direction, and the direction in which the light emitting unit 4 irradiates the light beam is defined as the z direction.

[0030] In Fig. 4, the light-emitting unit 4 has the light sources A1 and A2 shown in Fig. 2 arranged by rotating them 90 degrees counterclockwise with the +z direction facing. The irradiation surfaces 210 and 220 and the overlapping regions D1 and D2 are also arranged by rotating them 90 degrees counterclockwise with the +z direction facing. That is, in Fig. 4, the light sources A1 and A2 are positioned in this order in the -x direction, and the irradiation surfaces B1 and B2 and C1 and C2 are positioned in this order in the +x direction. Then, the irradiation surfaces B1 and B2 overlap in the x direction to form the overlapping region D1, and the irradiation surfaces C1 and C2 overlap in the x direction to form the overlapping region D2. When the object P1 is advancing in the +x direction and enters the irradiation surface 210, the object P1 enters the irradiation surface B1 before entering the overlapping region D1. The light-receiving unit 5 receives the light reflected by the object P1 that has exited from the light-emitting unit 4 and entered the irradiation surface B1 and outputs an electrical signal. Thereby, the control unit 8 detects the entry of the object P1 into the irradiation surface B1. Then, the control unit 8 detects that the object P1 is about to enter the overlapping region D1 and turns off a part of the plurality of light sources to eliminate the overlap of the overlapping region.

[0031] Here, the control unit 8 determines a part of the plurality of light sources to be turned off according to the advancing direction of the object P1. In Fig. 4, the object P1 is advancing in the +x direction and enters the overlapping region D1 from the irradiation surface B1 side. In this case, the control unit 8 first turns off the light source A2 to eliminate the overlap of the overlapping region D1. At this time, the irradiation surface 210 is in a state where only the irradiation surface B1 irradiated by the light source A1 is irradiated by the light-emitting unit 4. Then, when the object P1 further advances in the +x direction and exits from the irradiation surface B1, the control unit 8 turns on the light source A2 and turns off the light source A1. At this time, the irradiation surface 210 is in a state where only the irradiation surface B2 irradiated by the light source A2 is irradiated by the light-emitting unit 4, and the overlap of the overlapping region D1 is eliminated.

[0032] In this way, the control unit 8 determines a part of the plurality of light sources to be turned off according to the advancing direction of the object, thereby suppressing the entry of the object into the overlapping region while maintaining the irradiation state of the object. In the example shown in FIG. 4, the overlapping region D1 extends in a direction orthogonal to the entering direction of the object P1, but it is not limited to this. As long as it is the positional relationship of entering the irradiation surface B1 before the object P1 enters the overlapping region D1, the angles at which the light sources A1 and A2 are arranged can be changed.

[0033] Further, the control unit 8 may be configured to sequentially turn on a plurality of light sources A1 and A2 that irradiate the overlapping region D1 while eliminating the overlap of the overlapping region D1. With this configuration, while eliminating the overlap of the overlapping region D1 by turning off either one of the light sources A1 and A2, the entire irradiation region can be irradiated without omission. Furthermore, the control unit 8 may be configured to measure the distance to the object P1 based on the result received by the light receiving unit 5 during the period when the light sources A1 and A2 are sequentially turned on after sequentially turning on the plurality of light sources A1 and A2 that irradiate the overlapping region D1 with light rays. With this configuration, while eliminating the overlap of the overlapping region D1, the distance to the object existing in the entire irradiation region can be measured without omission.

[0034] Also, in FIG. 4, the case where the light emitting unit 4 includes two light sources A1 and A2 has been described, but the light emitting unit 4 may include three or more light sources. FIG. 5 is a diagram for explaining the relationship between the light emitting unit when three or more light sources are arranged such that the overlapping region extends in a direction intersecting the entering direction of the object, and the irradiation surface irradiated with the light emitted from the light emitting unit. In FIG. 5, similar to FIG. 4, the left direction with respect to the direction in which the light emitting unit 4 irradiates light rays is defined as the x direction, the upward direction on the paper surface is defined as the y direction, and the direction in which the light emitting unit 4 irradiates light rays is defined as the z direction.

[0035] In FIG. 5, the light emitting unit 4 includes four light sources A3, A4, A5, and A6, which are arranged along the x direction. The light rays from the light sources A3, A4, A5, and A6 shown in FIG. 5 irradiate the irradiation surfaces B3, B4, B5, and B6, respectively, and overlapping regions D3, D4, and D5 where the irradiation surfaces overlap are formed. The light sources A3, A4, A5, and A6 are located in this order in the -x direction, while the irradiation surfaces B3, B4, B5, and B6 are located in this order in the +x direction.

[0036] When the object P2 is moving in the +x direction, the object P2 first enters the irradiation surface B3. The control unit 8 detects the entry of the object P2 into the irradiation surface B3, and further detects that the object P2 is about to enter the overlapping region D3. Then, the control unit 8 first turns off the light source A4 to eliminate the overlap in the overlapping region D3. When the object P2 moves in the +x direction and exits from the irradiation surface B3, the control unit 8 turns on the light source A4 and turns off the light source A3. Next, the control unit 8 detects that the object P2 is about to enter the overlapping region D4. Then, the control unit 8 turns off the light source A5 to eliminate the overlap in the overlapping region D4. When the object P2 further moves in the +x direction and exits from the irradiation surface B4, the control unit 8 turns on the light source A5 and turns off the light source A4. Thus, even when the number of light sources increases, in the case where the overlapping region is arranged to extend in a direction intersecting the entry direction of the object, similar to the case shown in FIG. 4, before the object enters the overlapping region, it can be detected that the object "is about to enter", and the entry of the object into the overlapping region can be suppressed.

[0037] <Second Embodiment> (Distance Measuring Device 2) The distance measuring device 2 to which the second embodiment is applied includes an optical device 3 and a control unit 8, similar to the distance measuring device 1 to which the first embodiment is applied, but is different from the distance measuring device 1 in the configuration of the light emitting unit. For the same configuration as that in the first embodiment, the same reference numerals are used for description. The distance measuring device 2 includes a light receiving unit 5, a light emitting driving unit 6, a light receiving driving unit 7, and a control unit 8, similar to the distance measuring device 1, and includes a light emitting unit 9 having a different configuration from that of the distance measuring device 1.

[0038] (Light Emitting Unit 9) FIG. 6 is a diagram showing a configuration example of the light emitting unit 9 included in the distance measuring device 2 to which the second embodiment is applied. FIG. 6 shows a state as viewed from the side where the light emitting unit 9 emits light. Therefore, the right direction on the paper surface in FIG. 6 is the x direction, the upper direction on the paper surface is the y direction, and the front direction of the paper surface is the z direction. The light emitting unit 9 includes a plurality of light sources each having a light emitting surface 90 on which a plurality of VCSELs 93 are arranged. In the example shown in FIG. 6, the light emitting unit 9 includes two light sources A3 and A4. Then, the light emitting unit 9 emits light by the emission of the VCSELs 93. The light emitting surface 90 is divided into a plurality of light emitting sections 91 each including at least one VCSEL 93. In FIG. 6, as an example, the light emitting surface 90 is divided into a total of four light emitting sections 91, two in the x direction and two in the y direction.

[0039] Each light emitting section 91 is independently driven to emit light by the light emission driving unit 6. The light emission driving unit 6 drives each light emitting section 91 in response to a control signal from the control unit 8. Therefore, not all of the light emitting sections 91 necessarily emit light at the same time, and some of them may be in a state of being turned off. The control unit 8 determines the portion to be turned off among the plurality of light emitting sections 91. When all of the light emitting sections 91 emit light or are turned off at the same time, the distance measuring device 2 exhibits the same behavior as the distance measuring device 1 to which the first embodiment is applied. As shown in FIG. 6, in the light emitting unit 9, two light sources A3 and A4 are arranged side by side in the y direction, and each light source has a substrate 92 and a light emitting surface 90 on which a plurality of VCSELs 93 are arranged. More specifically, the substrate 92 and the light emitting surface 90 are provided so as to overlap in the direction of light emission (+z direction, the front direction of the paper surface).

[0040] FIG. 7 is a diagram for explaining the relationship between the light emitting unit 9 according to the second embodiment and the irradiation region irradiated with light from the light emitting unit 9. In FIG. 7, similar to FIG. 2, the left direction with respect to the direction in which the light emitting unit 9 irradiates light rays is defined as the x direction, the upward direction of the paper surface is defined as the y direction, and the direction in which the light emitting unit 9 irradiates light rays is defined as the z direction. In FIG. 7, the light emitting unit 9 includes two light sources A3 and A4 positioned in this order in the -y direction, and each light source is divided into a total of four light emitting sections 91 as shown in FIG. 6. As shown in FIG. 8 to be described later, each light emitting section 91 is distinguished as light emitting sections A11 to A18 in order from the upper left side (+x direction and +y direction ends) facing the light irradiation direction (+z direction). The light source A3 is divided into light emitting sections A11 to A14, and the light source A4 is divided into light emitting sections A15 to A18. FIG. 7 shows an example of the case where the light rays from the light sources A3 and A4 are irradiated so as to intersect.

[0041] The irradiation region irradiated with the light rays from the light sources A3 and A4 may have an overlapping region where the irradiation regions overlap depending on the distance from the light sources. The irradiation surfaces 230 and 240 are surfaces irradiated with the light from the light emitting unit 9 that are orthogonal to the direction in which the light is emitted within the irradiation region at a certain distance in the direction in which the light is emitted from the light emitting unit 9. In FIG. 7, the irradiation surface 240 is located at a distance where no overlap of the irradiation region occurs and uniform irradiation is performed on the irradiation surface, and the irradiation surface 230 is located in the direction (-z direction) closer to the light emitting unit 9 with respect to the irradiation surface 240.

[0042] As shown in FIG. 8 to be described later, the irradiation surface 230 is formed by irradiation surfaces B11 to B14 irradiated with the light rays from the light emitting sections A11 to A14 of the light source A3 and irradiation surfaces B15 to B18 irradiated with the light rays from the light emitting sections A15 to A18 of the light source A4. When the light rays from the light sources A3 and A4 are irradiated so as to intersect, on the irradiation surface 230, in order from the upper left side (+x direction and +y direction ends) facing the light irradiation direction (+z direction), the irradiation surfaces B15 to B18 and B11 to B14 are located. A partial region in the y direction of the irradiation surface B11 and the irradiation surface B17 and a partial region in the y direction of the irradiation surface B12 and the irradiation surface B18 overlap with each other, and overlapping regions D11 and D12 are respectively formed. The irradiation surface 240 is formed by irradiation surfaces C11 to C14 irradiated with light rays from the light-emitting sections A11 to A14 of the light source A3 and irradiation surfaces C15 to C18 irradiated with light rays from the light-emitting sections A15 to A18 of the light source A4. Each irradiation surface faces the light irradiation direction (+z direction), and in order from the upper left side (+x direction and +y direction ends), the irradiation surfaces C15 to C18 and C11 to C14 are located.

[0043] FIG. 8 is a diagram for explaining the relationship between the light-emitting unit 9 according to the second embodiment and the irradiation surfaces 230 and 240 irradiated with the light emitted from the light-emitting unit 9. In FIG. 8, the left direction of the paper surface is the x direction, the upper direction of the paper surface is the y direction, and the back side direction of the paper surface is the z direction. In FIG. 8, although the light-emitting unit 9 and the irradiation surfaces 230 and 240 are shown shifted in the vertical direction (±y direction) of the paper surface, the light-emitting unit 9 and the irradiation surfaces 230 and 240 are positioned to face each other. In FIG. 8, the light-emitting unit 4 is located in the front side direction (-z direction) of the paper surface, the irradiation surface 230 is located in the back side direction (+z direction) of the paper surface, and the irradiation surface 240 is located further in the back side direction (+z direction).

[0044] FIG. 9 is a diagram for explaining the relationship between the light-receiving surface 50 of the light-receiving unit 5 according to the second embodiment and the above-described irradiation surfaces 230 and 240. In FIG. 9, similar to FIG. 8, the left direction of the paper surface is the x direction, the upper direction of the paper surface is the y direction, and the back side direction of the paper surface is the z direction. In FIG. 9, although the light-receiving surface 50 and the irradiation surfaces 230 and 240 are shown shifted in the vertical direction (±y direction) of the paper surface, the light-receiving surface 50 and the irradiation surfaces 230 and 240 are arranged to face each other. In FIG. 9, the light-receiving unit 5 (light-receiving surface 50) is located in the front side direction (-z direction) of the paper surface, and the irradiation surfaces 230 and 240 are located in the back side direction (+z direction) of the paper surface.

[0045] The light-receiving surface 50 is divided into a plurality of light-receiving sections 51 corresponding to the light-emitting section 91 (see FIG. 7) of the light-emitting surface 90 and the irradiation surfaces 230 and 240. In the example of FIG. 9, it is divided into eight light-receiving sections 51 arranged in two in the x direction and four in the y direction. Each light-receiving section 51 is distinguished as light-receiving sections E11 to E18 in order from the upper left side (+x direction and +y direction ends) in FIG. 9. Each light-receiving section 51 receives light that is emitted from the light-emitting section 9 and reflected by an object existing on the corresponding irradiation surfaces 230 and 240. Each light-receiving section 51 is independently driven by a light-receiving drive section 7 (see FIG. 1) to perform a light-receiving operation.

[0046] (Operation control of the light-emitting section 9) An example of the control of the operation of the light-emitting section 9 by the control section 8 will be described using the example shown in FIG. 7. Similar to the first embodiment, when an object exists in an overlapping region where a problem may occur, the control section 8 turns off some of the plurality of light sources of the light-emitting section 9 to eliminate the overlap in the overlapping region. The plurality of light sources A3 and A4 included in the light-emitting section 9 are each divided into a plurality of light-emitting sections 91, and the control section 8 can eliminate the overlap in the overlapping region by turning off some of the light-emitting sections 91.

[0047] For example, assume that the overlapping region D12 shown in FIG. 7 is an overlapping region that satisfies a predetermined requirement in which a problem may occur when an object enters. In this case, when the object P3 enters the overlapping region D12, the control section 8 turns off some of the light-emitting sections 91 so as to eliminate the overlap in the overlapping region D12. The overlapping region D12 is formed by the overlap between the irradiation surface B12 and the irradiation surface B13, and the control section 8 eliminates the overlap in the overlapping region D12 by turning off either one of the corresponding light-emitting section A12 and the light-emitting section A18. Further, the control section 8 sequentially turns on the light-emitting section A12 and the light-emitting section A18 while eliminating the overlap in the overlapping region D12. Thereby, while eliminating the overlap in the overlapping region D12, the entire irradiation region can be irradiated without omission.

[0048] (Processing procedure by the control section 8) Subsequently, the processing performed by the control section 8 will be described. FIG. 10 is a flowchart showing the processing procedure by the control section 8. The control section 8 first causes light to be emitted from all the light-emitting sections 91 in the light-emitting section 9 (step 101).

[0049] Next, the control unit 8 determines whether an object exists in an overlapping area that satisfies a predetermined requirement (step 102). The overlapping area that satisfies the predetermined requirement is an overlapping area in which a problem may occur when the object enters. In step 102, the control unit 8 determines whether an object exists based on the result of light reception by the light receiving unit 5. If no object exists in the overlapping area that satisfies the predetermined requirement (NO in step 102), the control unit 8 returns to step 101 and continues the process.

[0050] On the other hand, if an object exists in the overlapping area that satisfies the predetermined requirement (YES in step 102), the control unit 8 identifies a light emitting section 91 that irradiates the overlapping area where the object exists (step 103). The control unit 8 identifies, based on the result of light reception by each light receiving section 51, the light emitting section that irradiates the overlapping area of the corresponding light emitting section 91. For example, when the control unit 8 detects entry into the overlapping area D12 in FIG. 7, the control unit 8 identifies the light emitting sections A12 and A18 as the light emitting sections that irradiate the overlapping area where the object exists.

[0051] Next, the control unit 8 turns off a part of the light emitting section 91 that irradiates the overlapping area where the object exists and sequentially turns it on (step 104). When the control unit 8 detects entry into the overlapping area D12 in FIG. 7, the control unit 8 turns off one of the light emitting sections A12 and A18 to eliminate the overlap in the overlapping area D12. Then, the control unit 8 sequentially turns on the light emitting sections A12 and A18 to irradiate the entire irradiation area without omission. Thus, a series of processes related to the operation control of the light emitting unit 9 by the control unit 8 is completed.

[0052] As described above, since each light source is divided into a plurality of light emitting sections 91, in the distance measuring device 2, finer turning-off control is possible compared to the distance measuring device 1. For example, in the example shown in FIG. 7, when there is a first object on the irradiation surface 240 where no overlap of the irradiation regions occurs and uniform irradiation is performed on the irradiation surface, and a second object enters the overlap regions D11 and D12 that satisfy the predetermined requirements, the control unit 8 turns off a part of the light-emitting sections 91 to eliminate the overlap of the overlap regions where the second object has entered while maintaining the irradiation of the first object.

[0053] For example, in FIG. 7, assume that there is a first object on the irradiation surface C13. Here, when the second object enters the overlap region D11 that satisfies the predetermined requirements, if each light source is not divided into a plurality of light-emitting sections 91, the control unit 8 will sequentially turn off and turn on the light sources A3 and A4 to suppress excessive irradiation of the second object, and it will not be possible to maintain the irradiation of the first object. Since each light source is divided into a plurality of light-emitting sections 91, the control unit 8 can turn off and turn on the light-emitting sections A11 and A17 sequentially to eliminate the overlap of the overlap region D11 while maintaining the irradiation of the first object.

[0054] (Modification example) In FIG. 7, the case where the light-emitting unit 9 has two light sources A3 and A4 has been described, but the light-emitting unit 9 may be configured to have three or more light sources. FIG. 11 is a diagram for explaining the relationship between the light-emitting unit 9 when the light-emitting unit 9 according to the second embodiment has four light sources A5, A6, A7, and A8 and the irradiation regions irradiated with light from the light-emitting unit 9.

[0055] In FIG. 11, similar to FIG. 7, the left direction with respect to the direction in which the light-emitting unit 9 irradiates light is defined as the x direction, the upward direction on the paper surface is defined as the y direction, and the direction in which the light-emitting unit 9 irradiates light is defined as the z direction. In FIG. 11, the light-emitting unit 9 includes four light sources A5, A6, A7, and A8 that are sequentially located from the upper left side (+x direction and +y direction ends) facing the light irradiation direction (+z direction). Each light source is divided into a total of four light-emitting sections 91 as shown in FIG. 6.

[0056] FIG. 11 shows an example in the case where light rays from light sources A5, A6, A7, and A8 are irradiated so as to intersect. The irradiation regions irradiated with the light rays from light sources A5, A6, A7, and A8 may have an overlapping region where the irradiation regions overlap depending on the distance from the light sources. The irradiation surfaces 250 and 260 are surfaces irradiated with light from the light emitting unit 9 that are orthogonal to the direction in which light is emitted from the light emitting unit 9 at a certain distance in the direction in which light is emitted within the irradiation region. In FIG. 11, the irradiation surface 260 is located at a distance where no overlap occurs in the irradiation region and uniform irradiation is performed on the irradiation surface, and the irradiation surface 250 is located in the direction (-z direction) closer to the light emitting unit 9 with respect to the irradiation surface 260.

[0057] The relationship between the light emitting unit 9 shown in FIG. 11 and the irradiation region irradiated with light from the light emitting unit 9 will be described with reference to FIGS. 12 to 14. FIG. 12 is a diagram for explaining the relationship between the light emitting unit 9 having four light sources A5, A6, A7, and A8 according to the second embodiment and the irradiation surface 260 irradiated with light from the light emitting unit 9. In FIG. 12, the left direction of the paper surface is the x direction, the upward direction of the paper surface is the y direction, and the back side direction of the paper surface is the z direction. FIG. 13 is a diagram for explaining the relationship between the light emitting unit 9 having four light sources A5, A6, A7, and A8 according to the second embodiment and the irradiation surfaces irradiated with light from the respective light sources A5, A6, A7, and A8. In FIG. 13, the left direction of the paper surface is the x direction, the upward direction of the paper surface is the y direction, and the back side direction of the paper surface is the z direction. In FIG. 13, the portions irradiated with light from each light source with respect to the irradiation surface 250 are shifted in the vertical direction (±y direction) of the paper surface in a separate figure, but each figure represents the same irradiation surface 250. FIG. 14 is a diagram for explaining the overlapping region of the irradiation regions in the case where the light emitting unit 9 according to the second embodiment has four light sources A5, A6, A7, and A8. FIG. 14 shows the overlapping region when the irradiation surfaces 250 shown in FIG. 13 are superimposed. In FIG. 14, the left direction of the paper surface is the x direction, the upward direction of the paper surface is the y direction, and the back side direction of the paper surface is the z direction.

[0058] As shown in Fig. 12, the light sources A5, A6, A7, and A8 of the light emitting unit 9 are each divided into four light emitting sections 91 (see Fig. 6), and are distinguished as light emitting sections A31 to A46 in order from the upper left side (+x direction and +y direction ends) facing the light irradiation direction (+z direction). The light source A5 is divided into light emitting sections A31 to A34, the light source A6 is divided into light emitting sections A35 to A38, the light source A7 is divided into light emitting sections A39 to A42, and the light source A8 is divided into light emitting sections A43 to A46. In Fig. 12, the light emitting unit 9 and the irradiation surface 260 are shown shifted in the vertical direction (±y direction) of the paper surface, but the light emitting unit 9 and the irradiation surface 260 are positioned to face each other. In Fig. 12, the light emitting unit 9 is located in the front side direction (-z direction) of the paper surface, and the irradiation surface 260 is located in the back side direction (+z direction) of the paper surface.

[0059] The irradiation surface 260 is formed by irradiation surfaces C31 to C34 irradiated with light rays from the light emitting sections A31 to A34 of the light source A5, irradiation surfaces C35 to C38 irradiated with light rays from the light emitting sections A35 to A38 of the light source A6, irradiation surfaces C39 to C42 irradiated with light rays from the light emitting sections A39 to A42 of the light source A7, and irradiation surfaces C43 to C46 irradiated with light rays from the light emitting sections A43 to A46 of the light source A8. The irradiation surface 260 has the irradiation surfaces C43 to C46, C39 to C42, C35 to C38, and C31 to C34 positioned in order from the upper left side (+x direction and +y direction ends) facing the light irradiation direction (+z direction).

[0060] As shown in Fig. 13, the irradiation surface 250 is formed by irradiation surfaces B31 to B34 irradiated with light rays from the light emitting sections A31 to A34 of the light source A5, irradiation surfaces B35 to B38 irradiated with light rays from the light emitting sections A35 to A38 of the light source A6, irradiation surfaces B39 to B42 irradiated with light rays from the light emitting sections A39 to A42 of the light source A7, and irradiation surfaces B43 to B46 irradiated with light rays from the light emitting sections A43 to A46 of the light source A8. When the light rays from each light source are irradiated so as to intersect, on the irradiation surface 250, the irradiation surfaces B43 to B46, B39 to B42, B35 to B38, and B31 to B34 are positioned in order from the upper left side (+x direction and +y direction ends) facing the light irradiation direction (+z direction).

[0061] As shown in FIG. 13, each irradiation surface has some regions overlapping as shown in FIG. 14, forming overlapping regions D31 to D39. More specifically, a part of the region in the y direction of the irradiation surface B35 and the irradiation surface B45, the irradiation surface B36 and the irradiation surface B46, the irradiation surface B31 and the irradiation surface B41, and the irradiation surface B32 and the irradiation surface B42 overlap, respectively, and the overlapping regions D31, D32, D38, and D39 are formed respectively. Also, a part of the region in the x direction of the irradiation surface B39 and the irradiation surface B44, the irradiation surface B46 and the irradiation surface B41, the irradiation surface B36 and the irradiation surface B31, and the irradiation surface B38 and the irradiation surface B33 overlap, respectively, and the overlapping regions D33, D34, D36, and D37 are formed respectively. Further, a part of the region in the x direction and the y direction of the irradiation surfaces B31, B36, B41, and B46 overlap, and the overlapping region D35 is formed.

[0062] The light receiving surface 50 of the light receiving unit 5 is divided into a plurality of light receiving sections 51 corresponding to the light emitting section 91 (see FIG. 12) of the light emitting surface 90 and the irradiation surfaces 250 and 260. Each light receiving section 51 receives the light emitted from the light emitting unit 9 and reflected by the object present on the corresponding irradiation surfaces 250 and 260. Each light receiving section 51 is independently driven by the light receiving driving unit 7 (see FIG. 1) to perform a light receiving operation.

[0063] (Operation control of the light emitting unit 9) Here, returning to FIG. 11, the operation control of the light emitting unit 9 when an object Q exists on the irradiation surface 260 and an object P4 enters the overlapping region of the irradiation surface 250 will be described. The object Q is an example of the first object, and the object P4 is an example of the second object. When the control unit 8 detects the entry of the object P4 into the overlapping region of the irradiation surface 250 based on the light receiving result by the light receiving unit 5, the control unit 8 determines whether the overlapping region where the object P4 has entered satisfies a predetermined requirement. When the overlapping region where the object P4 has entered satisfies the predetermined requirement, the control unit 8 turns off a part of the light emitting sections 91 that irradiate the overlapping region to eliminate the overlap of the overlapping region.

[0064] When the object P4 enters any of the overlapping regions D31, D32, D33, D34, D36, D37, D38, D39, the control unit 8 eliminates the overlap of the overlapping regions by turning off a part of the light-emitting sections 91 that irradiate each overlapping region. At this time, if the object Q exists on the irradiation surface 260, the overlap of the overlapping regions is eliminated while maintaining the irradiation of the object Q. For example, when the object Q exists on the irradiation surface C32 and the object P4 enters the overlapping region D39, the control unit 8 turns off the light-emitting section A42 among the light-emitting sections 91 that irradiate the overlapping region D39, and the light-emitting section A32 maintains the lighting state to eliminate the overlap of the overlapping region D39. In addition, a configuration may be adopted in which a plurality of light-emitting sections 91 that irradiate the overlapping region entered by the object P4 are sequentially turned on to irradiate the irradiation region without omission.

[0065] When the object P4 enters the overlapping region D35, the control unit 8 turns off three of the light-emitting sections A31, A36, A41, A46 that irradiate the overlapping region D35 to eliminate the overlapping region of the overlapping region D35. When the object Q exists on any of the irradiation surfaces C31, C36, C41, C46, the control unit 8 turns off the light-emitting section 91 corresponding to the irradiation surface where the object Q does not exist, and the light-emitting section 91 corresponding to the irradiation surface where the object Q exists maintains the lighting state to eliminate the overlap of the overlapping region D39. In addition, the control unit 8 may be configured to sequentially turn on the light-emitting sections A31, A36, A41, A46 to irradiate the irradiation region without omission. Further, for example, when the object P4 is long in the y direction and the object P4 also exists on the irradiation surfaces B33, B38, a configuration may be adopted in which all of the light-emitting sections A31, A36, A41, A46 are turned off, and the irradiation state of the object P4 is maintained by irradiation from the light-emitting section A33 or the light-emitting section A38.

[0066] Also, even when the light emitting unit 4 is arranged such that the overlapping region extends in a direction intersecting the entering direction of the object as shown in FIG. 4, the light emitting surface 90 may be configured to be divided into a plurality of light emitting sections 91. With this configuration, finer extinguishing control can be performed compared to the case where the distance measuring device 1 is used, and the period during which the object cannot be detected can be made shorter. FIG. 15 is a diagram for explaining the relationship between the light emitting unit 9 in which a plurality of light sources of the light emitting unit 9 whose light emitting surface 90 is divided into a plurality of light emitting sections 91 are arranged such that the overlapping region extends in a direction intersecting the entering direction of the object, and the irradiation surface 270 irradiated with the light emitted from the light emitting unit 9. In FIG. 15, similar to FIG. 11, the left direction with respect to the direction in which the light emitting unit 9 irradiates light rays is defined as the x direction, the upward direction on the paper surface is defined as the y direction, and the direction in which the light emitting unit 9 irradiates light rays is defined as the z direction.

[0067] The light emitting unit 9 shown in FIG. 15 has two light sources A9 and A10, and the light sources A9 and A10 are positioned in this order in the -x direction. The light sources A9 and A10 are each divided into two light emitting sections 91 in the x direction. The light source A9 has light emitting sections A21 and A22, and the light source A10 has light emitting sections A23 and A24. The light emitting sections A21, A22, A23, and A24 are positioned in this order in the -x direction. Also, in FIG. 15, an example in which the light rays from the light sources A9 and A10 are irradiated so as to intersect is shown.

[0068] The irradiation surface 270 is a surface irradiated with the light from the light emitting unit 9 that is orthogonal to the direction in which the light is emitted at a certain distance in the direction in which the light is emitted from the light emitting unit 9 within the irradiation region. The irradiation surface 270 is formed by an irradiation surface B21 irradiated with the light rays from the light emitting section A21, an irradiation surface B22 irradiated with the light rays from the light emitting section A22, an irradiation surface B23 irradiated with the light rays from the light emitting section A23, and an irradiation surface B24 irradiated with the light rays from the light emitting section A24. When irradiated so that the light rays from light sources A9 and A10 intersect, the light-emitting sections A21, A22, A23, A24 are positioned in this order in the -x direction, while the irradiation surfaces B21, B22, B23, B24 are positioned in this order in the +x direction. A partial region in the x direction of irradiation surface B22 and irradiation surface B23 overlaps, forming an overlapping region D21.

[0069] When the object P4 is moving in the +x direction and enters the irradiation surface 270, the object P4 enters the irradiation surfaces B21 and B22 before entering the overlapping region D21. When the object P4 enters the irradiation surfaces B21 and B22, the light receiving section 5 receives the light emitted from the light emitting section 9 and reflected by the object P4 and outputs an electrical signal. Thereby, the control section 8 detects the entry of the object P4 into the irradiation surfaces B21 and B22. Then, the control section 8 detects that the object P4 is about to enter the overlapping region D21, turns off a part of the plurality of light-emitting sections 91, and eliminates the overlap of the overlapping region.

[0070] Here, the control section 8 determines a part to be turned off among the plurality of light-emitting sections 91 according to the entry direction of the object P4. In FIG. 15, the object P4 is moving in the +x direction and enters the overlapping region D21 from the side of the irradiation surface B22. In this case, the control section 8 first turns off the light-emitting section A23 to eliminate the overlap of the overlapping region D21. At this time, the irradiation surface 270 is in a state where the irradiation surfaces B21, B22, and B24 are irradiated by the light emitting section 9.

[0071] Then, when the object P4 further moves in the +x direction and exits from the irradiation surface B22, the control section 8 turns on the light-emitting section A23 and turns off the light-emitting section A22. At this time, the irradiation surface 270 is in a state where the irradiation surfaces B21, B23, and B24 are irradiated by the light emitting section 9, and the overlap of the overlapping region D21 is eliminated. In this way, the control section 8 determines a part to be turned off among the plurality of light-emitting sections 91 according to the entry direction of the object, thereby suppressing the entry of the object into the overlapping region while maintaining the irradiation state of the object.

[0072] Note that, although an example in which each light-receiving section is independently driven to perform a light-receiving operation has been shown, the present invention is not limited thereto. Light reception may be performed in all the light-receiving sections. If the light emission timings for each light-emitting section are made different and the light-receiving operation is not performed only in the light-receiving sections corresponding to the light-emitting sections, there is a possibility of being affected by multipath noise or the like. Even in such a case, by making the light emission timings for each light-emitting section different, it is possible to suppress the power used at one time when irradiating a wider area as compared with the case where the timings are not made different.

[0073] (Appendix) (((1))) A light-emitting unit that irradiates light beams from a plurality of light sources in parallel to different irradiation regions, and a control unit that turns off a part of the plurality of light sources that irradiate light to the overlapping region when it is detected that an object has entered the overlapping region where the irradiation regions by the respective light sources overlap. A light-emitting device comprising the same. (((2))) The light-emitting unit is arranged such that the overlapping region extends in a direction intersecting the entry direction of the object. The light-emitting device according to ((1)). (((3))) The control unit determines the part to be turned off among the plurality of light sources according to the entry direction of the object. The light-emitting device according to ((2)). (((4))) Each of the plurality of light sources has a plurality of light-emitting sections, and the control unit determines the part to be turned off from among the plurality of light-emitting sections. The light-emitting device according to ((1)). (((5))) The light-emitting device according to ((1)), a light-receiving unit that receives the light beam emitted from the light-emitting unit and reflected by the object, and a distance measuring unit that measures the distance to the object based on the result of light reception in the light-receiving unit. A distance measuring device comprising the same. (((6))) The control unit turns off a part of the light source based on the result of light reception by the light receiving unit. The distance measuring device according to ((5)). (((7))) The control unit detects the entry of an object into the overlapping area based on the result of light reception by the light receiving unit, and turns off the light when the amount of light received by the light receiving unit exceeds a predetermined value. The distance measuring device according to ((6)). (((8))) The control unit turns off the light when the distance to the object is closer than a predetermined distance. The distance measuring device according to ((6)). (((9))) Each of the plurality of light sources has a plurality of light emitting sections. When a first object exists in the irradiation area and the control unit detects the entry of a second object into the overlapping area that satisfies a predetermined requirement, the control unit turns off a part of the plurality of light emitting sections so as to eliminate the overlap of the overlapping area where the second object has entered while maintaining the irradiation to the first object. The light emitting device according to ((1)). (((10))) When the control unit detects the entry of an object into the overlapping area, the control unit sequentially turns on a plurality of light sources that irradiate the overlapping area while eliminating the overlap of the overlapping area. The light emitting device according to ((1)). (((11))) After sequentially turning on a plurality of light sources that irradiate light rays into the overlapping area, the distance measuring unit measures the distance to the object based on the result of light reception by the light receiving unit during the period when the light sources are sequentially turned on. The distance measuring device according to ((5)).

[0074] According to the inventions of ((1)) and ((5)), it is possible to suppress the amount of light irradiated to an object that has entered the overlapping area from becoming excessive as compared with the case where a part of a plurality of light sources that irradiate light rays causing an overlap in the irradiation area is not turned off. According to the invention of ((2)), the overlap of the overlapping region can be eliminated before the object enters the overlapping region. According to the invention of ((3)), the overlap of the overlapping region can be eliminated while maintaining the state of irradiating the object. According to the invention of ((4)), compared with the case of not having a plurality of light-emitting sections, the overlap of the overlapping region can be eliminated more finely. According to the invention of ((6)), it is possible to suppress the amount of light irradiated to the object that has entered the overlapping region from becoming excessive based on the light reception result. According to the invention of ((7)), it is possible to eliminate the state where the amount of light received by the light-receiving unit is excessive. According to the invention of ((8)), when the object enters an overlapping region closer than a predetermined distance, it is possible to eliminate the state where the amount of light irradiated to the object becomes excessive. According to the invention of ((9)), when there are a plurality of objects and one object enters an overlapping region that satisfies a predetermined requirement, it is possible to eliminate the overlap of the overlapping region where one object has entered while maintaining the irradiation to the other objects. According to the invention of ((10)), it is possible to irradiate the entire irradiation region without omission while eliminating the overlap of the overlapping region where the object has entered. According to the invention of ((11)), it is possible to measure the distance to the object existing in the entire irradiation region without omission while eliminating the overlap of the overlapping region where the object has entered.

Explanation of Reference Numerals

[0075] 1, 2... distance measuring device, 3... optical device, 4, 9... light-emitting section, 5... light-receiving section, 6... light-emitting drive section, 7... light-receiving drive section, 8... control section, 50... light-receiving surface, 51... light-receiving section, 81... CPU, 82... ROM, 83... RAM, 90... light-emitting surface, 91... light-emitting section, 92... substrate, 93... VCSEL

Claims

1. A light emitting unit that irradiates light rays from a plurality of light sources in parallel to different irradiation regions, and a control unit that turns off a part of the plurality of light sources that irradiate the overlapping region when it detects the entry of an object into the overlapping region where the irradiation regions by the respective light sources overlap. A light emitting device comprising the above.

2. The light emitting unit is arranged such that the overlapping region extends in a direction intersecting the entry direction of the object. The light emitting device according to Claim 1.

3. The control unit determines the part of the plurality of light sources to be turned off according to the entry direction of the object. The light emitting device according to Claim 2.

4. Each of the plurality of light sources has a plurality of light emitting sections, and the control unit determines the part to be turned off from among the plurality of light emitting sections. The light emitting device according to Claim 1.

5. The light emitting device according to Claim 1, a light receiving unit that receives the light rays emitted from the light emitting unit and reflected by the object, and a distance measuring unit that measures the distance to the object based on the result of light reception in the light receiving unit. A distance measuring device comprising the above.

6. The control unit turns off a part of the light sources based on the result of light reception by the light receiving unit. The distance measuring device according to Claim 5.

7. The control unit detects the entry of the object into the overlapping region based on the result of light reception by the light receiving unit, and turns off the light when the amount of light received by the light receiving unit exceeds a predetermined value. The distance measuring device according to Claim 6.

8. The control unit turns off the light when the distance to the object is closer than a predetermined distance. The distance measuring device according to Claim 6.

9. Each of the plurality of light sources has a plurality of light emitting sections, and when the control unit detects the presence of a first object in the irradiation region and the entry of a second object into the overlapping region that satisfies a predetermined requirement, the control unit turns off a part of the plurality of light emitting sections so as to eliminate the overlap of the overlapping region where the second object has entered while maintaining the irradiation to the first object. The light emitting device according to Claim 1.

10. When the control unit detects the entry of an object into the overlapping region, the control unit sequentially turns on the plurality of light sources that irradiate the overlapping region while eliminating the overlap of the overlapping region. The light emitting device according to Claim 1.

11. The distance measuring unit measures the distance to the object based on the result of light reception by the light receiving unit during the period when the light sources are sequentially turned on after sequentially turning on the plurality of light sources that irradiate the overlapping region. The distance measuring device according to claim 5.

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