Light emitting device and distance measuring device

Abstract

A light-emitting device and a distance measuring apparatus, the light-emitting device being provided with: 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, when it is detected that an object enters an overlapping region where the irradiation regions of the light sources overlap, turns off some of the plurality of light sources that irradiate light to the overlapping region.

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 causes a light source to preliminarily emit light, controls the light emission amount of main light emission according to the light reception amount of each light reception area, and measures the distance to a distance measurement object.

[0003] Patent Document 2 describes a three-dimensional measurement device that includes a human sensor for detecting a person and controls the output of a laser beam according to whether information indicating that no person exists within a detection range is received.

[0004] Patent Document 1: Japanese Unexamined Patent Application Publication No. 2020-160044

[0005] Patent Document 2: Japanese Patent Application Publication No. 2018-120989 Summary of the Invention

[0006] There is a distance measuring device that measures the distance to an object (referred to as "distance measurement") by a so-called time-of-flight (TOF: Time Of Flight) method that measures the time from when light is emitted until the light reflected by the object is received. In such a distance measuring device, by irradiating different areas with a plurality of light sources, it is possible to perform distance measurement on a wider area compared to the case of a single light source.

[0007] However, when irradiating different irradiation areas with light beams from a plurality of light sources side by side, sometimes an overlap of the irradiation areas occurs depending on the distance from the light sources. In the overlapping area where the irradiation areas overlap, the amount of light increases, so when an object enters the overlapping area, the amount of light irradiated on the object becomes excessive.

[0008] An object of the present invention is to suppress the amount of light irradiated on an object that has entered an overlapping area from becoming excessive compared to the case where a part of a plurality of light sources that irradiate light causing the overlap of the irradiation areas is not extinguished.

[0009] The invention according to Scheme 1 is a light-emitting device including: a light-emitting unit that irradiates different irradiation areas with light beams from a plurality of light sources side by side; and a control unit that extinguishes a part of the plurality of light sources that irradiate light on the overlapping area when it is detected that an object enters an overlapping area where the irradiation areas based on the respective light sources overlap.

[0010] The invention according to Scheme 2 is the light-emitting device according to Scheme 1, wherein the light-emitting unit is configured such that the overlapping area extends in a direction intersecting the entering direction of the object.

[0011] The invention according to Embodiment 3 is the light-emitting device according to Embodiment 2, wherein the control unit determines the part of the plurality of light sources to be extinguished based on the entering direction of the object.

[0012] The invention according to Embodiment 4 is the light-emitting device according to Embodiment 1, wherein each of the plurality of light sources has a plurality of light-emitting sections, and the control unit determines the part to be extinguished from the plurality of light-emitting sections.

[0013] The invention according to Embodiment 5 is a distance measuring device, comprising: the light-emitting device according to Embodiment 1; a light receiving unit that receives light emitted from the light-emitting unit and reflected by an object; and a distance measuring unit that measures the distance to the object based on the light reception result of the light receiving unit.

[0014] The invention according to Embodiment 6 is the distance measuring device according to Embodiment 5, wherein the control unit extinguishes a part of the light sources based on the light reception result of the light receiving unit.

[0015] The invention according to Embodiment 7 is the distance measuring device according to Embodiment 6, wherein the control unit detects the entry of the object into the overlapping area based on the light reception result of the light receiving unit, and turns off the light when the light reception amount of the light receiving unit exceeds a preset value.

[0016] The invention according to Embodiment 8 is the distance measuring device according to Embodiment 6, wherein when the distance to the object is closer than a preset distance, the control unit turns off the light.

[0017] The invention according to Embodiment 9 is the light-emitting device according to Embodiment 1, wherein each of the plurality of light sources has a plurality of light-emitting sections, and when a first object exists in the irradiation area and it is detected that a second object enters the overlapping area that satisfies a preset necessary condition, the control unit extinguishes a part of the plurality of light-emitting sections to eliminate the overlap of the overlapping area where the second object enters while maintaining the irradiation state to the first object.

[0018] The invention according to Embodiment 10 is the light-emitting device according to Embodiment 1, wherein when it is detected that an object enters the overlapping area, the control unit eliminates the overlap of the overlapping area and sequentially turns on the plurality of light sources that irradiate the overlapping area.

[0019] The invention according to Embodiment 11 is the distance measuring device according to Embodiment 5, wherein after sequentially turning on the plurality of light sources that irradiate the overlapping area, during the period of sequentially turning on the light sources, the distance measuring unit measures the distance to the object based on the result of the light received by the light receiving unit.

[0020] Advantages of the Invention

[0021] According to the first and fifth aspects of the present invention, compared with the case where a part of a plurality of light sources that do not extinguish the overlapping light rays generating an irradiation region is used, it is possible to suppress an excessive amount of light irradiated to an object that has entered the overlapping region.

[0022] According to the second aspect of the present invention, it is possible to eliminate the overlap in the overlapping region before the object enters the overlapping region.

[0023] According to the third aspect of the present invention, it is possible to maintain the state of irradiating the object and eliminate the overlap in the overlapping region.

[0024] According to the fourth aspect of the present invention, compared with the case where there are no multiple light-emitting partitions, it is possible to eliminate the overlap in the overlapping region in a more detailed manner.

[0025] According to the sixth aspect of the present invention, it is possible to suppress an excessive amount of light irradiated to an object that has entered the overlapping region based on the light reception result.

[0026] According to the seventh aspect of the present invention, it is possible to eliminate the state where the amount of light received in the light receiving unit is excessive.

[0027] According to the eighth aspect of the present invention, it is possible to eliminate the state where the amount of light irradiated to an object becomes excessive when the object enters an overlapping region closer than a preset distance.

[0028] According to the ninth aspect of the present invention, when there are multiple objects and one object enters an overlapping region that satisfies a preset necessary condition, it is possible to maintain the irradiation to the other object and eliminate the overlap in the overlapping region entered by the one object.

[0029] According to the tenth aspect of the present invention, it is possible to eliminate the overlap in the overlapping region entered by the object and irradiate the entire irradiation region without omission.

[0030] According to the eleventh aspect of the present invention, it is possible to eliminate the overlap in the overlapping region entered by the object and measure the distance to the object existing in the entire irradiation region without omission. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] The embodiments of the present invention will be described in detail with reference to the following drawings.

[0032] Figure 1 is a block diagram showing an example of the schematic configuration of a distance measuring device to which the first embodiment is applied;

[0033] Figure 2 is a diagram for explaining the relationship between the light-emitting unit according to the first embodiment and the irradiation region where light is irradiated from the light-emitting unit;

[0034] Figure 3It is a diagram for explaining the relationship between the light-emitting part according to the first embodiment and the irradiation surface irradiated with the light emitted from the light-emitting part;

[0035] Figure 4 It is a diagram for explaining the relationship between the light-emitting part when a plurality of light sources are arranged such that the overlapping region extends in a direction intersecting the entering direction with respect to the object and the irradiation surface irradiated with the light emitted from the light-emitting part;

[0036] Figure 5 It is a diagram for explaining the relationship between the light-emitting part when three or more light sources are arranged such that the overlapping region extends in a direction intersecting the entering direction with respect to the object and the irradiation surface irradiated with the light emitted from the light-emitting part;

[0037] Figure 6 It is a diagram showing a structural example of the light-emitting part included in the distance measuring device to which the second embodiment is applied;

[0038] Figure 7 It is a diagram for explaining the relationship between the light-emitting part according to the second embodiment and the irradiation region irradiated with the light from the light-emitting part;

[0039] Figure 8 It is a diagram for explaining the relationship between the light-emitting part according to the second embodiment and the irradiation surface irradiated with the light emitted from the light-emitting part;

[0040] Figure 9 It is a diagram for explaining the relationship between the light-receiving surface of the light-receiving part according to the second embodiment and the above-mentioned irradiation surface;

[0041] Figure 10 It is a flowchart showing the steps of the processing performed by the control unit;

[0042] Figure 11 It is a diagram for explaining the relationship between the light-emitting part when the light-emitting part according to the second embodiment has four light sources and the irradiation region irradiated with the light from the light-emitting part;

[0043] Figure 12 It is a diagram for explaining the relationship between the light-emitting part when the light-emitting part according to the second embodiment has four light sources and the irradiation surface irradiated with the light emitted from the light-emitting part;

[0044] Figure 13 It is a diagram for explaining the relationship between the light-emitting part when the light-emitting part according to the second embodiment has four light sources and the irradiation surfaces irradiated with the light from each light source;

[0045] Figure 14 It is a diagram for explaining the overlapping region of the irradiation regions when the light-emitting part according to the second embodiment has four light sources;

[0046] Figure 15 This is a diagram for explaining the relationship between a light emitting part in which a light emitting surface is divided into a plurality of light emitting areas and a plurality of light sources, and an irradiation surface irradiated with light emitted from the light emitting part when an overlapping area extends in a direction crossing the entering direction with respect to an object.

[0047] Symbol Explanation

[0048] 1, 2 - Distance measuring devices, 3 - Optical device, 4, 9 - Light emitting parts, 5 - Light receiving part, 6 - Light emitting drive part, 7 - Light receiving drive part, 8 - Control part, 50 - Light receiving surface, 51 - Light receiving area, 81 - CPU, 82 - ROM, 83 - RAM, 90 - Light emitting surface, 91 - Light emitting area, 92 - Substrate, 93 - VCSEL. Detailed Embodiment

[0049] Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

[0050] <First Embodiment>

[0051] (Distance Measuring Device 1)

[0052] Figure 1 This is a block diagram showing an example of the schematic structure of the distance measuring device 1 to which the first embodiment is applied.

[0053] The distance measuring device 1 measures the distance to an object based on the result of the light receiving part 5 described later receiving the light emitted from the light emitting part 4 described later and reflected by the object. The distance measuring device 1 measures the distance to the object from the distance measuring device 1 to the object, for example, according to the ToF (Time of Flight) method. Incidentally, the distance measuring device 1 measures the distance to the object based on the time from the moment when the light is emitted from the light emitting part 4 to the moment when the emitted light is reflected by the object and received by the light receiving part 5. In the ToF method, there are: an indirect ToF (iToF: indirect ToF) method that measures the time based on the difference in phase between the emitted light and the received light; and a direct ToF (dToF: direct ToF) method that directly measures the time from the emission of light to the reception of light. Here, the indirect ToF method and the direct ToF method are not distinguished and are described as the ToF method.

[0054] As Figure 1 shown, the distance measuring device 1 includes an optical device 3 and a control part 8.

[0055] The optical device 3 includes: a light emitting part 4 that emits light toward a preset irradiation range; a light receiving part 5 that receives the light emitted from the light emitting part 4 and reflected by an object existing within the irradiation range; a light emitting drive part 6 that drives the light emitting part 4; and a light receiving drive part 7 that drives the light receiving part 5.

[0056] The control unit 8 controls the operations of the light emitting unit 4 and the light receiving unit 5 of the optical device 3.

[0057] Further, the control unit 8 obtains the light reception result 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 the light reception result.

[0058] The control unit 8 is an example of the distance measuring unit.

[0059] (Light emitting unit 4)

[0060] The light emitting unit 4 includes a plurality of light sources each having a light emitting surface on 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.

[0061] The light emitting unit 4 irradiates light rays from the 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) to a plane perpendicular to the emission direction and irradiated. As the diffusion unit, a diffusion plate that is provided on the optical path of light and diffuses 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 component such as a lens can be used.

[0062] The light rays from the plurality of light sources of the light emitting unit 4 can be irradiated in parallel or in a crossed manner. The light rays from the plurality of light sources sometimes cause an overlap of their irradiation regions depending on the distance from the light sources. An Figure 2 explanation of the overlap of the irradiation regions will be given.

[0063] Figure 2 This is a diagram for explaining the relationship between the light emitting unit 4 according to the first embodiment and the irradiation region where light is irradiated from the light emitting unit 4. Figure 2 This shows an example in which the light emitting unit 4 includes two light sources A1 and A2, and the light rays from the light sources A1 and A2 are irradiated in a crossed manner. In Figure 2 , the left direction with respect to the direction in which the light emitting unit 4 irradiates light 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 4 irradiates light is defined as the z direction. In Figure 2 , the light source A1 is arranged in the upward direction (+y direction) of the paper surface with respect to the light source A2.

[0064] Each of the light sources A1 and A2 is driven by a light emission driving unit 6 (refer to Figure 1) They are driven independently to emit light. Driving the light sources A1 and A2 means supplying power to the VCSELs included in the light sources A1 and A2 to cause them to emit light. And "driven independently" means driving the light sources A1 and A2 separately to emit light. The light emission driving unit 6 drives each of the light sources A1 and A2 according to a control signal from the control unit 8 (reference Figure 1 )).

[0065] Therefore, Figure 2 the light sources A1 and A2 in the example do not necessarily emit light simultaneously. For example, a state where the light source A1 emits light but the light source A2 does not emit light can be adopted.

[0066] The irradiation regions irradiated by the light from the light sources A1 and A2 sometimes have an overlapping region where the irradiation regions overlap according to the distance from the light sources.

[0067] The irradiation surfaces 210 and 220 are surfaces irradiated by the light from the light emitting unit 4 that are orthogonal to the direction of the emitted light at a certain distance in the direction of the emitted light within the irradiation region. In Figure 2 it, 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.

[0068] The irradiation surface 210 is formed by the irradiation surface B1 irradiated by the light from the light source A1 and the irradiation surface B2 irradiated by the light from the light source A2. When the light from the light sources A1 and A2 irradiates in a crossed manner, the light sources A1 and A2 are sequentially located in the -y direction. In contrast, the irradiation surfaces B1 and B2 are sequentially located in the +y direction. A part of the regions of the irradiation surfaces B1 and B2 in the y direction overlap to form an overlapping region D1.

[0069] The irradiation surface 220 is formed by the irradiation surface C1 irradiated by the light from the light source A1 and the irradiation surface C2 irradiated by the light from the light source A2. When the light from the light sources A1 and A2 irradiates in a crossed manner, the light sources A1 and A2 are sequentially located in the -y direction. In contrast, the irradiation surfaces C1 and C2 are sequentially located in the +y direction. A part of the regions of the irradiation surfaces C1 and C2 in the y direction overlap to form an overlapping region D2.

[0070] When the light from the light sources A1 and A2 irradiates in a crossed manner, the farther the distance from the light emitting unit 4, the narrower the width in the y direction of the overlapping region where the irradiation regions overlap. At a position further away from the light emitting unit 4 compared to the irradiation surface 220, the width of the overlapping region becomes even narrower, and no overlapping region is formed at a certain distance.

[0071] Figure 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 by the light emitted from the light emitting unit 4. In Figure 3In this case, the left direction of the paper surface is the x direction, the upper direction of the paper surface is the y direction, and the inner direction of the paper surface is the z direction. Additionally, in Figure 3 it is shown that the light emitting part 4 and the irradiation surfaces 210 and 220 are displaced in the vertical direction (±y direction) of the paper surface, but the light emitting part 4 and the irradiation surfaces 210 and 220 are arranged to face each other. In Figure 3 the light emitting part 4 is located in the front side direction (-z direction) of the paper surface, the irradiation surface 210 is located in the inner side direction (+z direction) of the paper surface, and the irradiation surface 220 is located in an even more inner side direction (+z direction).

[0072] The irradiation surface 220 is located in the direction away from the light emitting part 4 (+z direction) with respect to the irradiation surface 210, and the width in the y direction of the overlapping region D2 formed on the irradiation surface 220 is narrower than that of the overlapping region D1 formed on the irradiation surface 210.

[0073] (Light receiving part 5)

[0074] The light receiving part 5 has a light receiving surface that diffuses in the x and y directions and on which a plurality of light receiving elements are arranged. Moreover, the light receiving part 5 receives, through each light receiving element, the light emitted from the light emitting part 4 and reflected by an object present in the irradiation region.

[0075] The light receiving surface is divided into a plurality of light receiving partitions corresponding to the plurality of light sources of the light emitting part 4. As Figure 2 shown, when the light emitting part 4 has two light sources A1 and A2, the light receiving surface is divided into two light receiving partitions in the y direction. Each light receiving partition has a plurality of light receiving elements arranged regularly. Each light receiving element receives the light emitted from the light emitting part 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 or a phototransistor.

[0076] Each light receiving partition is independently driven by a light receiving driving part 7 (refer to Figure 1 ) to perform a light receiving operation. The driving of the light receiving partition means changing the state of the light receiving elements included in the light receiving partition from a state where they cannot receive light to a state where they can receive light and output an electrical signal. And "independently driven" means being set to a state where each light receiving partition is driven to be able to receive light and output an electrical signal. The light receiving driving part 7 drives each light receiving partition according to a control signal from a control part 8 (refer to Figure 1 ).

[0077] Moreover, when the light receiving elements included in each light receiving partition receive light, they output an electrical signal corresponding to the received light to the control part 8.

[0078] (Control part 8)

[0079] Return toFigure 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.

[0080] The CPU 81 is an example of a processor, and realizes various functions described later by loading various programs stored in the ROM 82 and the like into the RAM 83 and executing them. The RAM 83 is a memory used as a working memory of the CPU 81 and the like. The ROM 82 is a memory that stores various programs executed by the CPU 81 and the like.

[0081] 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 disc, etc.), a magneto-optical recording medium, or a semiconductor memory. Also, the program executed by the CPU 81 can be provided using a communication unit such as the Internet.

[0082] Also, in the first embodiment, the processor refers to a processor in a broad sense and includes a general-purpose processor (e.g., CPU: Central Processing Unit, etc.), a dedicated processor (e.g., GPU: Graphics Processing Unit, ASIC: Application Specific Integrated Circuit, FPGA: Field Programmable Gate Array, programmable logic device, etc.).

[0083] Also, the operations of the processor in the first embodiment can be executed not only by one processor but also by multiple processors located at physically separate positions cooperating with each other. Also, the order of each operation of the processor is not limited to the order described in the first embodiment and can be changed.

[0084] 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.

[0085] 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 uses the ToF method described above and 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. Incidentally, the control unit 8 calculates the distance between the distance measuring device 1 and the object by performing a preset arithmetic process on the electrical signal acquired from the light receiving element of the light receiving unit 5, and creates a distance image.

[0086] (Operation control of the light emitting unit 4)

[0087] Use Figure 2 The example shown below illustrates an example of the control of the operation of the light emitting unit 4 by the control unit 8.

[0088] As Figure 2 shown, the irradiation areas irradiated by the light rays from the light sources A1 and A2 have an overlapping area according to the distance from the light sources. For example, an overlapping area D1 is formed on the irradiation surface 210, and the overlapping area D1 is an area where the amount of irradiated light becomes larger. When there is an object in the overlapping area D1, there may be a problem that the amount of light irradiated on the object becomes excessive.

[0089] For example, signal saturation may occur in the light receiving element that receives the light reflected by the object existing in the overlapping area D1, which may hinder the measurement. Also, there may be adverse conditions caused by the concentration of light.

[0090] When there is an object in the overlapping area where such a problem may occur, the control unit 8 turns off a part of the plurality of light sources of the light emitting unit 4 to eliminate the overlap of the overlapping area. In Figure 2 the example shown, the control unit 8 eliminates the overlap of the overlapping area by turning off the light source A1, for example.

[0091] Moreover, the control unit 8 may be configured not to perform the control of turning off a part of the light sources when there is no problem even when there is an object in the overlapping area. The case where there is no problem means, for example, that the distance between the overlapping area where the object enters and the light source is widened, and the amount of light irradiated on the object does not become excessive.

[0092] When it is detected that the object enters the overlapping area, the control unit 8 determines whether the overlapping area satisfies a preset necessary condition. The preset necessary condition is a criterion for whether there is a problem when the object enters the overlapping area. When the overlapping area satisfies the preset necessary condition, the control unit 8 turns off a part of the plurality of light sources of the light emitting unit 4 to eliminate the overlap of the overlapping area.

[0093] Here, "detecting entry" includes "detecting the case of having entered" and "detecting the case of about to enter".

[0094] The control unit 8 detects the entry of the object into the overlapping area based on the light reception result of the light reception unit 5, and determines whether the overlapping area where the object enters satisfies a preset necessary condition.

[0095] For example, the preset necessary condition is determined based on the light reception amount in the light reception unit 5 or the distance between the entering object and the light emitting unit 4. When determining whether the preset necessary condition is satisfied based on the light reception amount in the light reception unit 5, it is determined whether the light reception amount exceeds a threshold value that causes signal saturation in the light reception unit 5. When the light reception amount exceeds the threshold value, the control unit 8 turns off a part of the plurality of light sources. In addition, the threshold value is a preset value that can be freely set, and is not limited to the case of signal saturation, and a threshold value that may cause problems can be set.

[0096] When determining whether the preset necessary condition is satisfied based on the distance between the entering object and the light emitting unit 4, the control unit 8 measures the distance to the object based on the light reception result of the light reception unit 5, and determines whether it is closer than the preset distance. When the distance between the object and the light emitting unit 4 is closer than the preset distance, the control unit 8 turns off a part of the plurality of light sources.

[0097] For example, in Figure 2 , it is assumed that the overlapping area D1 of the irradiation surface 210 is an area that satisfies the preset necessary condition, and the overlapping area D2 of the irradiation surface 220 is an area that does not satisfy the preset necessary condition. In this case, when the object enters the overlapping area D1, the control unit 8 turns off either the light source A1 or A2 to eliminate the overlap of the overlapping area. On the other hand, even if the object enters the overlapping area D2, the control unit 8 does not perform the extinguishing control.

[0098] When the extinguishing control is performed after detecting that the object has entered an overlapping area where problems may occur, the object is temporarily irradiated in a manner that may cause problems. For example, in the case where the object is conveyed by a belt conveyor and the entry direction of the object is constant, the light emitting unit 4 is arranged such that the overlapping area extends in a direction intersecting the entry direction of the object, whereby it is possible to detect the entry before the object enters the overlapping area.

[0099] Figure 4 FIG. is a diagram for explaining the relationship between the light emitting unit 4 when the plurality of light sources are arranged such that the overlapping area 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.

[0100] In Figure 4 with Figure 2Similarly, the left direction with respect to the direction in which the light-emitting unit 4 irradiates light is set as the x direction, the upward direction on the paper surface is set as the y direction, and the direction in which the light-emitting unit 4 irradiates light is set as the z direction.

[0101] Figure 4 The light-emitting unit 4 in Figure 2 is a configuration in which the light sources A1 and A2 shown are rotated counterclockwise by 90 degrees toward the +z direction. The irradiation surfaces 210, 220 and the overlapping regions D1, D2 also become configurations rotated counterclockwise by 90 degrees toward the +z direction. That is, in Figure 4 , the light sources A1 and A2 are sequentially located in the -x direction, and the irradiation surfaces B1, B2 and C1, C2 are sequentially located in the +x direction. Moreover, 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.

[0102] When the object P1 advances 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 emitted from the light-emitting unit 4 and reflected by the object P1 that has entered the irradiation surface B1 and outputs an electrical signal, whereby 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 in the overlapping region.

[0103] Here, the control unit 8 determines a part of the plurality of light sources to be turned off according to the entry direction of the object P1. In Figure 4 , the object P1 advances in the +x direction and enters the overlapping region D1 from the side of the irradiation surface B1. In this case, the control unit 8 first turns off the light source A2 to eliminate the overlap in the overlapping region D1. At this time, the irradiation surface 210 becomes a state in which the irradiation surface B1 irradiated only by the light source A1 is irradiated by the light-emitting unit 4.

[0104] Then, the object P1 further advances in the +x direction. When the object P1 leaves 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 becomes a state in which the irradiation surface B2 irradiated only by the light source A2 is irradiated by the light-emitting unit 4, thereby eliminating the overlap in the overlapping region D1.

[0105] In this way, the control unit 8 determines a part of the plurality of light sources to be turned off according to the entry direction of the object, maintains the irradiation state toward the object, and suppresses the entry of the object into the overlapping region.

[0106] In addition, in Figure 4In the example shown, the overlapping region D1 extends in a direction orthogonal to the entering direction of the object P1, but is not limited thereto. 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 of the light sources A1 and A2 can be changed.

[0107] Moreover, the control unit 8 can be configured to eliminate the overlap of the overlapping region D1 and to sequentially turn on the multiple light sources A1 and A2 that irradiate the overlapping region D1. According to this configuration, the overlap of the overlapping region D1 can be eliminated by turning off either of the light sources A1 and A2, and the entire irradiation region can be irradiated without omission.

[0108] Furthermore, the control unit 8 can be configured to measure the distance to the object P1 based on the result of the light received by the light receiving unit 5 during the sequential lighting of the multiple light sources A1 and A2 that irradiate light on the overlapping region D1 after the sequential lighting. According to this configuration, the overlap of the overlapping region D1 can be eliminated, and the distance to the object existing in the entire irradiation region can be measured without omission.

[0109] And, in Figure 4 the case where the light emitting unit 4 has two light sources A1 and A2 has been described, but the light emitting unit 4 can have three or more light sources.

[0110] Figure 5 FIG. is a diagram for explaining the relationship between the light emitting unit and the irradiation surface irradiated with the light emitted from the light emitting unit when three or more light sources are arranged such that the overlapping region extends in a direction crossing the entering direction of the object.

[0111] In Figure 5 similar to Figure 4 the left direction with respect to the direction in which the light emitting unit 4 irradiates light 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 4 irradiates light is defined as the z direction.

[0112] In Figure 5 the light emitting unit 4 has four light sources A3, A4, A5, and A6 and is arranged along the x direction. The light from Figure 5 the light sources A3, A4, A5, and A6 shown irradiates 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 sequentially located in the -x direction, and in contrast, the irradiation surfaces B3, B4, B5, and B6 are sequentially located in the +x direction.

[0113] When the object P2 moves 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 then detects that the object P2 is about to enter the overlapping area D3. Then, the control unit 8 first turns off the light source A4 to eliminate the overlap of the overlapping area D3. When the object P2 moves in the +x direction and leaves the irradiation surface B3, the control unit 8 turns on the light source A4 and turns off the light source A3.

[0114] Next, the control unit 8 detects that the object P2 is about to enter the overlapping area D4. Then, the control unit 8 turns off the light source A5 to eliminate the overlap of the overlapping area D4. When the object P2 further moves in the +x direction and leaves the irradiation surface B4, the control unit 8 turns on the light source A5 and turns off the light source A4.

[0115] Thus, even when the number of light sources increases, when the overlapping region is arranged to extend in a direction intersecting with the direction in which the object enters, Figure 4 Similarly to the case shown, the “imminent entry” of the object can be detected before the object enters the overlapping area, thereby suppressing the entry of the object into the overlapping area.

[0116] <Second embodiment>

[0117] (Distance measuring device 2)

[0118] The distance measuring device 2 according to the second embodiment includes an optical device 3 and a control unit 8 similarly to the distance measuring device 1 according to the first embodiment, but differs from the distance measuring device 1 in the structure of the light emitting unit. The same components as those of the first embodiment are denoted by the same reference numerals for description.

[0119] Similar to the distance measuring device 1 , the distance measuring device 2 includes a light receiving unit 5 , a light emission driving unit 6 , a light receiving driving unit 7 , and a control unit 8 , and also includes a light emitting unit 9 having a different structure from that of the distance measuring device 1 .

[0120] (Light emitting unit 9)

[0121] Figure 6 FIG. 2 is a diagram showing a configuration example of a light emitting unit 9 included in a distance measuring device 2 to which the second embodiment is applied. Figure 6 FIG. 8 shows a state observed from the side where light is emitted from the light emitting portion 9. Figure 6 The right direction of the paper is the x direction, the upper direction of the paper is the y direction, and the surface direction of the paper is the z direction.

[0122] The light emitting unit 9 includes a plurality of light sources having a light emitting surface 90 on which a plurality of VCSELs 93 are arranged. Figure 6 In the example shown, the light emitting unit 9 includes two light sources A3 and A4 . The light emitting unit 9 emits light by light emission of the VCSEL 93 .

[0123] The light emitting surface 90 is divided into a plurality of light emitting partitions 91 including at least one VCSEL 93. Among Figure 6 them, as an example, the light emitting surface 90 is divided into a total of four light emitting partitions 91, two in the x direction and two in the y direction.

[0124] Each light emitting partition 91 is independently driven by the light emission driving unit 6 to emit light. The light emission driving unit 6 drives each light emitting partition 91 according to a control signal from the control unit 8. Therefore, not all of the light emitting partitions 91 necessarily emit light simultaneously, and a state in which only a part of them is extinguished can be adopted. The control unit 8 determines the part to be extinguished from among the plurality of light emitting partitions 91. In addition, when all of the light emitting partitions 91 emit light or are extinguished simultaneously, the distance measuring device 2 exhibits the same behavior as the distance measuring device 1 to which the first embodiment is applied.

[0125] As Figure 6 shown, in the light emitting unit 9, two light sources A3 and A4 are arranged 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 arranged to overlap in the direction of the emitted light (+z direction, the front side direction of the paper surface).

[0126] Figure 7 FIG. 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. Among Figure 7 them, in the same manner as Figure 2 , the left direction with respect to the direction of the light irradiated from the light emitting unit 9 is set as the x direction, the upper direction of the paper surface is set as the y direction, and the direction of the light irradiated from the light emitting unit 9 is set as the z direction.

[0127] Among Figure 7 them, the light emitting unit 9 includes two light sources A3 and A4 that are sequentially located in the -y direction. As Figure 6 shown, each light source is divided into a total of four light emitting partitions 91. As will be described later, as Figure 8 shown, each light emitting partition 91 is sequentially divided into light emitting partitions A11 to A18 from the upper left side (+x direction and +y direction ends) toward the light irradiation direction (+z direction). The light source A3 is divided into light emitting partitions A11 to A14, and the light source A4 is divided into light emitting partitions A15 to A18. Figure 7 FIG. shows an example in which the light rays from the light sources A3 and A4 are irradiated in a crossed manner.

[0128] The irradiation regions irradiated with the light rays from the light sources A3 and A4 sometimes have an overlapping region in which the irradiation regions overlap depending on the distance from the light sources.

[0129] The irradiation surfaces 230 and 240 are surfaces irradiated by light from the light-emitting unit 9 that are orthogonal to the direction of the emitted light at a certain distance in the direction of the light emitted from the light-emitting unit 9 within the irradiation region. In Figure 7 the irradiation surface 240 is located at a distance where the irradiation regions do not overlap and the irradiation surface is uniformly irradiated, and the irradiation surface 230 is located in the direction closer to the light-emitting unit 9 (-z direction) with respect to the irradiation surface 240.

[0130] As described later in Figure 8 the irradiation surface 230 is formed by irradiation surfaces B11 to B14 irradiated by light rays from the light-emitting partitions A11 to A14 of the light source A3 and irradiation surfaces B15 to B18 irradiated by light rays from the light-emitting partitions A15 to A18 of the light source A4. When the light rays from the light sources A3 and A4 irradiate in a crossing manner, on the irradiation surface 230, the irradiation surfaces B15 to B18 and B11 to B14 are arranged in sequence in the direction of the light irradiation (+z direction) from the upper left side (the ends in the +x direction and +y direction). A partial region in the y direction of the irradiation surface B11 and B17 and a partial region in the y direction of the irradiation surface B12 and B18 overlap with each other, respectively forming an overlapping region D11 and an overlapping region D12.

[0131] The irradiation surface 240 is formed by irradiation surfaces C11 to C14 irradiated by light rays from the light-emitting partitions A11 to A14 of the light source A3 and irradiation surfaces C15 to C18 irradiated by light rays from the light-emitting partitions A15 to A18 of the light source A4. Each irradiation surface is arranged in sequence in the direction of the light irradiation (+z direction) from the upper left side (the ends in the +x direction and +y direction) as the irradiation surfaces C15 to C18 and C11 to C14.

[0132] Figure 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 by the light emitted from the light-emitting unit 9. In Figure 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 inner direction of the paper surface is the z direction. In addition, in Figure 8 the light-emitting unit 9 and the irradiation surfaces 230 and 240 are shown offset in the vertical direction (±y direction) of the paper surface, but the light-emitting unit 9 and the irradiation surfaces 230 and 240 are arranged opposite to each other. In Figure 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 inner direction (+z direction) of the paper surface, and the irradiation surface 240 is located in the further inner direction (+z direction).

[0133] Figure 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-mentioned irradiation surfaces 230 and 240. In Figure 9 it is the same as Figure 8Similarly, the left direction of the paper surface is set as the x direction, the upper direction of the paper surface is set as the y direction, and the inner direction of the paper surface is set as the z direction. Additionally, in Figure 9 , the light receiving surface 50 and the irradiation surfaces 230 and 240 are shown offset in the vertical direction (±y direction) of the paper surface, but the light receiving surface 50 and the irradiation surfaces 230 and 240 are arranged to face each other. In Figure 9 , the light receiving unit 5 (light receiving surface 50) is located on the front side direction (-z direction) of the paper surface, and the irradiation surfaces 230 and 240 are located on the inner side direction (+z direction) of the paper surface.

[0134] The light receiving surface 50 and the light emitting partitions 91 of the light emitting surface 90 (refer to Figure 7 ) and the irradiation surfaces 230 and 240 are correspondingly divided into a plurality of light receiving partitions 51. In Figure 9 's example, it is divided into eight light receiving partitions 51 arranged in two in the x direction and four in the y direction. Each light receiving partition 51 is sequentially divided into light receiving partitions E11 to E18 from the upper left side (+x direction and +y direction end) in Figure 9 .

[0135] Each light receiving partition 51 receives the light emitted from the light emitting unit 9 and reflected by the object existing on the corresponding irradiation surfaces 230 and 240. Each light receiving partition 51 is independently driven by the light receiving driving unit 7 (refer to Figure 1 ) to perform the light receiving operation.

[0136] (Operation control of the light emitting unit 9)

[0137] Using the example shown in Figure 7 , the control example of the operation of the light emitting unit 9 by the control unit 8 will be described.

[0138] Similar to the first embodiment, when there is an object in the overlapping area where problems may occur, the control unit 8 turns off a part of the plurality of light sources of the light emitting unit 9 to eliminate the overlap in the overlapping area. The plurality of light sources A3 and A4 of the light emitting unit 9 are respectively divided into a plurality of light emitting partitions 91, and the control unit 8 can eliminate the overlap in the overlapping area by turning off any part of the light emitting partitions 91.

[0139] For example, it is assumed that the overlapping area D12 shown in Figure 7 is an overlapping area that satisfies the preset necessary conditions where problems may occur when an object enters. In this case, if the object P3 enters the overlapping area D12, the control unit 8 turns off a part of the light emitting partitions 91 to eliminate the overlap in the overlapping area D12. The overlapping area D12 is formed by the overlap of the irradiation surface B12 and the irradiation surface B18, and the control unit 8 eliminates the overlap in the overlapping area D12 by turning off either the corresponding light emitting partition A12 or the light emitting partition A18.

[0140] Further, the control unit 8 eliminates the overlap in the overlapping area D12 and sequentially lights up the light-emitting partitions A12 and A18. Thereby, the overlap in the overlapping area D12 can be eliminated, and the entire irradiation area can be irradiated without omission.

[0141] (Processing steps performed by the control unit 8)

[0142] Next, the processing performed by the control unit 8 will be described. Figure 10 It is a flowchart showing the steps of the processing performed by the control unit 8.

[0143] The control unit 8 first emits light from all the light-emitting partitions 91 in the light-emitting unit 9 (step S101).

[0144] Next, the control unit 8 determines whether there is an object in the overlapping area that satisfies the preset necessary conditions (step S102). The overlapping area that satisfies the preset necessary conditions is the overlapping area where problems may occur when an object enters. In step S102, the control unit 8 determines whether there is an object based on the light reception result of the light reception unit 5.

[0145] When there is no object in the overlapping area that satisfies the preset necessary conditions (No in step S102), the control unit 8 returns to step S101 and continues the processing.

[0146] On the other hand, when there is an object in the overlapping area that satisfies the preset necessary conditions (Yes in step S102), the control unit 8 determines the light-emitting partition 91 that irradiates the overlapping area where the object exists (step S103). The control unit 8 determines the corresponding light-emitting partition 91 as the light-emitting partition that irradiates the overlapping area based on the result of light reception by each light reception partition 51.

[0147] For example, in Figure 7 , when the control unit 8 detects the entry into the overlapping area D12, the control unit 8 determines the light-emitting partitions A12 and A18 as the light-emitting partitions that irradiate the overlapping area where the object exists.

[0148] Next, the control unit 8 turns off a part of the light-emitting partitions 91 that irradiate the overlapping area where the object exists and sequentially lights them up (step S104). In Figure 7 , when the control unit 8 detects the entry into the overlapping area D12, the control unit 8 turns off either of the light-emitting partitions A12 and A18 to eliminate the overlap in the overlapping area D12. Then, the control unit 8 sequentially lights up the light-emitting partitions A12 and A18 to irradiate the entire irradiation area without omission.

[0149] Thus, a series of processes related to the operation control of the light-emitting unit 9 by the control unit 8 are terminated.

[0150] As described above, by dividing each light source into a plurality of light-emitting partitions 91, in the distance measuring device 2, more detailed extinguishing control can be performed compared to the distance measuring device 1.

[0151] For example, in Figure 7 In the example shown, when there is a first object on the irradiation surface 240 where the irradiation surface is uniformly irradiated without overlapping of the irradiation regions, and a second object P3 enters the overlapping regions D11 and D12 that satisfy the preset necessary conditions, the control unit 8 extinguishes a part of the light-emitting partitions 91 to eliminate the overlap of the overlapping regions where the second object enters while maintaining the irradiation of the first object.

[0152] For example, in Figure 7 it is assumed that there is a first object on the irradiation surface C13. Here, when a second object enters the overlapping region D11 that satisfies the preset necessary conditions, if each light source is not divided into a plurality of light-emitting partitions 91, the control unit 8 sequentially extinguishes and lights the light sources A3 and A4 in order to suppress excessive irradiation of the second object, and thus the irradiation of the first object cannot be maintained. By dividing each light source into a plurality of light-emitting partitions 91, the control unit 8 can maintain the irradiation of the first object and eliminate the overlap of the overlapping region D11 by sequentially extinguishing and lighting the light-emitting partitions A11 and A17.

[0153] (Modification example)

[0154] In Figure 7 it is described that the light-emitting unit 9 has two light sources A3 and A4, but the light-emitting unit 9 can be configured to have three or more light sources.

[0155] Figure 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 region where light is irradiated from the light-emitting unit 9.

[0156] In Figure 11 similar to 7, the left direction with respect to the direction of the light irradiated from the light-emitting unit 9 is set as the x direction, the upper direction of the paper surface is set as the y direction, and the direction of the light irradiated from the light-emitting unit 9 is set as the z direction. In Figure 11 the light-emitting unit 9 includes four light sources A5, A6, A7, and A8 that are sequentially arranged from the upper left side (+x direction and +y direction ends) toward the light irradiation direction (+z direction). As Figure 6 shown, each light source is divided into a total of four light-emitting partitions 91.

[0157] Figure 11 An example is shown in which light rays from light sources A5, A6, A7, and A8 are irradiated in a crossed manner. The irradiation regions irradiated by the light rays from light sources A5, A6, A7, and A8 sometimes have overlapping regions where their irradiation regions overlap according to the distance from the light sources.

[0158] The irradiation surfaces 250 and 260 are surfaces irradiated by light from the light emitting unit 9 that are orthogonal to the direction of the emitted light at a certain distance in the direction of the light emitted from the light emitting unit 9 within the irradiation region. In Figure 11 the irradiation surface 260 is located at a distance where no overlapping of the irradiation regions occurs and the irradiation surface is uniformly irradiated, and the irradiation surface 250 is located in the direction (-z direction) closer to the light emitting unit 9 relative to the irradiation surface 260.

[0159] Using Figures 12 to 14 to Figure 11 illustrate the relationship between the light emitting unit 9 shown and the irradiation region irradiated by the light from the light emitting unit 9.

[0160] Figure 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 by the light from the light emitting unit 9. In Figure 12 the left direction of the paper surface is the x direction, the upper direction of the paper surface is the y direction, and the inner direction of the paper surface is the z direction.

[0161] Figure 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 by the light from each of the light sources A5, A6, A7, and A8. In Figure 13 the left direction of the paper surface is the x direction, the upper direction of the paper surface is the y direction, and the inner direction of the paper surface is the z direction. In Figure 13 for the portion of the irradiation surface 250 irradiated by the light from each light source, in another diagram, it is shown shifted in the vertical direction (±y direction) of the paper surface, but each diagram shows the same irradiation surface 250.

[0162] Figure 14 is a diagram for explaining the overlapping region of the irradiation regions when the light emitting unit 9 according to the second embodiment has four light sources A5, A6, A7, and A8. Figure 14 represents the overlapping region when the respective irradiation surfaces 250 shown Figure 13 are overlapped. In Figure 14 the left direction of the paper surface is the x direction, the upper direction of the paper surface is the y direction, and the inner direction of the paper surface is the z direction.

[0163] As Figure 12As shown, the light sources A5, A6, A7, and A8 of the light-emitting unit 9 are each divided into four light-emitting sections 91 (refer to Figure 6 ), and are sequentially divided into light-emitting sections A31 to A46 from the upper left side (+x direction and +y direction ends) toward 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 addition, in Figure 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 arranged to face each other. In Figure 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.

[0164] The irradiation surface 260 is formed by irradiation surfaces C31 to C34 irradiated by light from the light-emitting sections A31 to A34 of the light source A5, irradiation surfaces C35 to C38 irradiated by light from the light-emitting sections A35 to A38 of the light source A6, irradiation surfaces C39 to C42 irradiated by light from the light-emitting sections A39 to A42 of the light source A7, and irradiation surfaces C43 to C46 irradiated by light from the light-emitting sections A43 to A46 of the light source A8. The irradiation surfaces C43 to C46, C39 to C42, C35 to C38, and C31 to C34 are sequentially arranged on the irradiation surface 260 from the upper left side (+x direction and +y direction ends) toward the light irradiation direction (+z direction).

[0165] As Figure 13 shown, the irradiation surface 250 is formed by irradiation surfaces B31 to B34 irradiated by light from the light-emitting sections A31 to A34 of the light source A5, irradiation surfaces B35 to B38 irradiated by light from the light-emitting sections A35 to A38 of the light source A6, irradiation surfaces B39 to B42 irradiated by light from the light-emitting sections A39 to A42 of the light source A7, and irradiation surfaces B43 to B46 irradiated by light from the light-emitting sections A43 to A46 of the light source A8.

[0166] When the light from each light source irradiates in a crossed manner, the irradiation surfaces B43 to B46, B39 to B42, B35 to B38, and B31 to B34 are sequentially arranged on the irradiation surface 250 from the upper left side (+x direction and +y direction ends) toward the light irradiation direction (+z direction).

[0167] As Figure 14 shown, Figure 13A part of the irradiation surfaces shown overlaps to form overlapping regions D31 to D39. More specifically, a part of the irradiation surface B35 overlaps with the irradiation surface B45, a part of the irradiation surface B36 overlaps with the irradiation surface B46, a part of the irradiation surface B31 overlaps with the irradiation surface B41, and a part of the irradiation surface B32 overlaps with the irradiation surface B42 in the y direction, respectively forming overlapping regions D31, D32, D38, and D39. Also, a part of the irradiation surface B39 overlaps with the irradiation surface B44, a part of the irradiation surface B46 overlaps with the irradiation surface B41, a part of the irradiation surface B36 overlaps with the irradiation surface B31, and a part of the irradiation surface B38 overlaps with the irradiation surface B33 in the x direction, respectively forming overlapping regions D33, D34, D36, and D37. Moreover, a part of the irradiation surfaces B31, B36, B41, and B46 in the x direction and y direction overlaps to form overlapping region D35.

[0168] The light receiving surface 50 of the light receiving unit 5 is divided into a plurality of light receiving partitions 51 corresponding to the light emitting partitions 91 (refer to Figure 12 ) of the light emitting surface 90 and the irradiation surfaces 250 and 260. Each light receiving partition 51 receives light emitted from the light emitting unit 9 and reflected by an object present on the corresponding irradiation surfaces 250 and 260. Each light receiving partition 51 is independently driven by a light receiving drive unit 7 (refer to Figure 1 ) to perform a light receiving operation.

[0169] (Operation control of the light emitting unit 9)

[0170] Here, returning to Figure 11 , the operation control of the light emitting unit 9 when an object Q is present on the irradiation surface 260 and the object P4 enters the overlapping region of the irradiation surface 250 will be described. The object Q is an example of a first object, and the object P4 is an example of a second object.

[0171] When it is detected based on the light receiving result of the light receiving unit 5 that the object P4 enters the overlapping region of the irradiation surface 250, the control unit 8 determines whether the overlapping region entered by the object P4 satisfies a preset necessary condition. When the overlapping region entered by the object P4 satisfies the preset necessary condition, the control unit 8 eliminates the overlap of the overlapping region by extinguishing a part of the light emitting partitions 91 that irradiate the overlapping region.

[0172] When the object P4 enters any one of the overlapping regions D31, D32, D33, D34, D36, D37, D38, D39, the control unit 8 eliminates the overlap of the overlapping regions by extinguishing a part of the light-emitting partitions 91 that irradiate each overlapping region. At this time, when the object Q exists on the irradiation surface 260, the overlap of the overlapping regions is eliminated while maintaining the irradiation state to 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 extinguishes the light-emitting partition A42 in the light-emitting partitions 91 that irradiate the overlapping region D39, and the light-emitting partition A32 maintains the lit state to eliminate the overlap of the overlapping region D39.

[0173] In addition, it can be set to sequentially light up a plurality of light-emitting partitions 91 of the overlapping region into which the object P4 enters, and irradiate the irradiation region without omission.

[0174] When the object P4 enters the overlapping region D35, the control unit 8 extinguishes three of the light-emitting partitions A31, A36, A41, A46 that irradiate the overlapping region D35 to eliminate the overlap of the overlapping region D35. When the object Q exists on any one of the irradiation surfaces C31, C36, C41, C46, the control unit 8 extinguishes the light-emitting partitions 91 corresponding to the irradiation surfaces where the object Q does not exist, and the light-emitting partitions 91 corresponding to the irradiation surfaces where the object Q exists maintain the lit state to eliminate the overlap of the overlapping region D39.

[0175] In addition, the control unit 8 can be set to sequentially light up the light-emitting partitions A31, A36, A41, A46, and irradiate the irradiation region without omission.

[0176] And, for example, it can also be set to a structure in which when the object P4 is long in the y direction and the object P4 also exists on the irradiation surfaces B33, B38, all the light-emitting partitions A31, A36, A41, A46 are extinguished, and the irradiation state to the object P4 is maintained by the irradiation from the light-emitting partition A33 or the light-emitting partition A38.

[0177] And, as Figure 4 shown, it can be set to a structure in which even when the light-emitting unit 4 is arranged such that the overlapping region extends in a direction crossing the entering direction of the object, the light-emitting surface 90 is divided into a plurality of light-emitting partitions 91. According to this structure, compared with the case of using the distance measuring device 1, more detailed extinguishing control can be performed, so that the period during which the object cannot be detected can be further shortened.

[0178] Figure 15This 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 that divides the light-emitting surface 90 into a plurality of light-emitting partitions 91 are arranged so that the overlapping regions extend in a direction intersecting the entering direction with respect to the object, and the irradiation surface 270 irradiated with the light emitted from the light-emitting unit 9. In Figure 15 it is the same as Figure 11 that the left direction with respect to the direction in which the light-emitting unit 9 irradiates light is set as the x direction, the upward direction of the paper surface is set as the y direction, and the direction in which the light-emitting unit 9 irradiates light is set as the z direction.

[0179] Figure 15 The light-emitting unit 9 shown in Figure 15 has two light sources A9 and A10, and the light sources A9 and A10 are sequentially located in the -x direction. The light sources A9 and A10 are each divided into two light-emitting partitions 91 in the x direction. The light source A9 has light-emitting partitions A21 and A22, and the light source A10 has light-emitting partitions A23 and A24. The light-emitting partitions A21, A22, A23, and A24 are sequentially located in the -x direction. And, in Figure 15 an example is shown in which the light rays from the light sources A9 and A10 are irradiated in a crossing manner.

[0180] The irradiation surface 270 is a surface irradiated with the light from the light-emitting unit 9 that is orthogonal to the direction of the emitted light at a certain distance in the direction of the emitted light within the irradiation region. The irradiation surface 270 is formed by an irradiation surface B21 irradiated with the light from the light-emitting partition A21, an irradiation surface B22 irradiated with the light from the light-emitting partition A22, an irradiation surface B23 irradiated with the light from the light-emitting partition A23, and an irradiation surface B24 irradiated with the light from the light-emitting partition A24.

[0181] When the light rays from the light sources A9 and A10 are irradiated in a crossing manner, the light-emitting partitions A21, A22, A23, and A24 are sequentially located in the -x direction. In contrast, the irradiation surfaces B21, B22, B23, and B24 are sequentially located in the +x direction. A part of the region of the irradiation surface B22 overlaps with the irradiation surface B23 in the x direction to form an overlapping region D21.

[0182] When the object P4 advances 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. If the object P4 enters the irradiation surfaces B21 and B22, the light-receiving unit 5 receives the light emitted from the light-emitting unit 9 and reflected by the object P4 and outputs an electric signal, whereby the control unit 8 detects the entry of the object P4 into the irradiation surfaces B21 and B22. Then, the control unit 8 detects that the object P4 is about to enter the overlapping region D21, and turns off a part of the plurality of light-emitting partitions 91 to eliminate the overlap of the overlapping region.

[0183] Here, the control unit 8 determines a part of the plurality of light-emitting sections 91 that is extinguished based on the entry direction of the object P4. In Figure 15 the object P4 advances in the +x direction and enters the overlapping region D21 from the irradiation surface B22 side. In this case, the control unit 8 first extinguishes the light-emitting section A23 to eliminate the overlap in 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 unit 9.

[0184] Then, as the object P4 further advances in the +x direction and leaves the irradiation surface B22, the control unit 8 lights up the light-emitting section A23 and extinguishes 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 unit 9, and the overlap in the overlapping region D21 is eliminated.

[0185] In this way, by determining a part of the plurality of light-emitting sections 91 that is extinguished based on the entry direction of the object, the control unit 8 maintains the irradiation state toward the object and suppresses the entry of the object into the overlapping region.

[0186] In addition, an example in which each light-receiving section is independently driven to perform a light-receiving operation is shown, but it is not limited thereto. It may also be configured to receive light in all the light-receiving sections. When the light-emitting times of each light-emitting section are different and the light-receiving operation is not set to be only for the light-receiving sections corresponding to the light-emitting sections, it may be affected by multipath noise or the like. However, even in this case, by making the light-emitting times of each light-emitting section different, compared with the case where the times are not different, the power used at one time when irradiating a wide area can be suppressed.

[0187] (Supplementary Note)

[0188] (1) A light-emitting device, comprising:

[0189] a light-emitting unit that irradiates light from a plurality of light sources in parallel to different irradiation regions; and

[0190] a control unit that, when detecting the entry of an object into an overlapping region where the irradiation regions based on the respective light sources overlap, extinguishes a part of the plurality of light sources that irradiate light to the overlapping region.

[0191] (2) The light-emitting device according to (1), wherein

[0192] the light-emitting unit is configured such that the overlapping region extends in a direction intersecting the entry direction of the object.

[0193] (3) The light-emitting device according to (2), wherein

[0194] The control unit determines the extinguished part of the plurality of light sources according to the entry direction of the object.

[0195] (4) The light emitting device according to (1), wherein

[0196] The plurality of light sources each have a plurality of light emitting partitions,

[0197] The control unit determines the extinguished part from among the plurality of light emitting partitions.

[0198] (5) A distance measuring device, comprising:

[0199] (1) The light emitting device as described above;

[0200] A light receiving unit that receives light emitted from the light emitting unit and reflected by an object; and

[0201] A distance measuring unit that measures the distance to the object based on the light reception result in the light receiving unit.

[0202] (6) The distance measuring device according to (5), wherein

[0203] The control unit extinguishes a part of the light sources based on the light reception result of the light receiving unit.

[0204] (7) The distance measuring device according to (6), wherein

[0205] The control unit detects the entry of the object into the overlapping region based on the light reception result of the light receiving unit, and turns off the lights when the light reception amount based on the light receiving unit exceeds a preset value.

[0206] (8) The distance measuring device according to (6), wherein

[0207] When the distance to the object is closer than a preset distance, the control unit turns off the lights.

[0208] (9) The light emitting device according to (1), wherein

[0209] The plurality of light sources each have a plurality of light emitting partitions,

[0210] When a first object exists in the irradiation area and it is detected that a second object enters the overlapping region that satisfies a preset necessary condition, the control unit extinguishes a part of the plurality of light emitting partitions so as to eliminate the overlap of the overlapping region where the second object enters while maintaining the irradiation state to the first object.

[0211] (10) The light emitting device according to (1), wherein

[0212] When an object is detected to enter the overlapping area, the control unit eliminates the overlap of the overlapping area and sequentially turns on a plurality of the light sources that irradiate the overlapping area.

[0213] (11) The distance measuring device according to (5), wherein

[0214] After sequentially turning on a plurality of the light sources that irradiate light on the overlapping area, during the period of sequentially turning on the light sources, the distance measuring unit measures the distance to the object based on the result of the light received by the light receiving unit.

[0215] According to the inventions of (1) and (5), compared with the case where a part of a plurality of light sources that do not turn off the light that generates the overlap of the irradiation area is not turned off, it is possible to suppress the amount of light irradiated on an object that has entered the overlapping area from becoming excessive.

[0216] According to the invention of (2), it is possible to eliminate the overlap of the overlapping area before the object enters the overlapping area.

[0217] According to the invention of (3), it is possible to maintain the state of irradiating the object and eliminate the overlap of the overlapping area.

[0218] According to the invention of (4), compared with the case where there are no multiple light emitting partitions, it is possible to eliminate the overlap of the overlapping area more carefully.

[0219] According to the invention of (6), it is possible to suppress the amount of light irradiated on an object that has entered the overlapping area from becoming excessive based on the light reception result.

[0220] According to the invention of (7), it is possible to eliminate the state where the amount of light received in the light receiving unit is excessive.

[0221] According to the invention of (8), it is possible to eliminate the state where the amount of light irradiated on an object becomes excessive when the object enters an overlapping area closer than a preset distance.

[0222] According to the invention of (9), when there are multiple objects and one object enters an overlapping area that satisfies a preset necessary condition, it is possible to maintain the irradiation to the other object and eliminate the overlap of the overlapping area entered by one object.

[0223] According to the invention of (10), it is possible to eliminate the overlap of the overlapping area entered by the object and irradiate the entire irradiation area without omission.

[0224] According to the invention of (11), it is possible to eliminate the overlap of the overlapping area entered by the object and measure the distance to the objects existing in the entire irradiation area without omission.

[0225] The above-described embodiments of the present invention are provided for purposes of illustration and description. In addition, the embodiments of the present invention do not comprehensively and exhaustively cover the present invention and do not limit the present invention to the disclosed manner. Obviously, various modifications and variations are apparent to those skilled in the art to which the present invention pertains. This embodiment is selected and described in order to most easily illustrate the principles of the present invention and its applications. Thus, other technicians in the art can understand the present invention through various modified examples that are optimized for specific uses assumed to be various embodiments. The scope of the present invention is defined by the above claims and their equivalents.

Claims

1. A light emitting device comprising: a light emitting unit for irradiating different irradiation areas with light from a plurality of light sources in parallel; and The control unit turns off part of the plurality of light sources irradiating light to the overlapping area when detecting an entry of an object into an overlapping area where the irradiation areas of the light sources overlap.

2. The light emitting device according to claim 1, wherein: The light emitting section is arranged so that the overlapping region extends in a direction intersecting with the entering direction of the object.

3. 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 entering direction of the object.

4. The light emitting device according to claim 1, wherein: The plurality of light sources respectively have a plurality of light-emitting partitions, The control unit determines a portion to be turned off from among the plurality of light-emitting subareas.

5. A distance measuring device comprising: The light-emitting device according to claim 1; a light receiving unit that receives light emitted from the light emitting unit and reflected by an object; and The distance measuring unit measures the distance to the object based on the result of light reception by the light receiving unit.

6. The distance measuring device according to claim 5, wherein: The control unit turns off a part of the light sources according to a light reception result by the light receiving unit.

7. The distance measuring device according to claim 6, wherein: The control unit detects entry of an object into the overlapping area based on a result of light reception by the light receiving unit, and turns off the light when an amount of light received by the light receiving unit exceeds a preset value.

8. The distance measuring device according to claim 6, wherein: When the distance to the object is shorter than a preset distance, the control unit turns off the light.

9. The light emitting device according to claim 1, wherein: The plurality of light sources respectively have a plurality of light-emitting partitions, When there is a first object in the irradiation area and when the entry of a second object into the overlapping area that satisfies a predetermined necessary condition is detected, the control unit extinguishes a portion of the plurality of light-emitting partitions to eliminate the overlap of the overlapping area into which the second object enters while maintaining irradiation of the first object.

10. The light emitting device according to claim 1, wherein: When the entry of the object into the overlapping area is detected, the control unit eliminates the overlap of the overlapping area and sequentially turns on the plurality of light sources illuminating the overlapping area.

11. The distance measuring device according to claim 5, wherein: After the plurality of light sources for irradiating the overlapping region are sequentially turned on, the distance measuring unit measures the distance to the object based on the result of the light receiving unit receiving the light while the light sources are sequentially turned on.

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