Light irradiation device, optical distance measurement device, and vehicle

Abstract

To enable light beam control to reduce an irradiation region within a distance measurement target region in a light irradiation device that does not use a lens unit. Provided is a light irradiation device (2) which is provided in an optical distance measurement device (1) and which irradiates a distance measurement target region (5) with a light beam, said light irradiation device (2) being provided with: a light source (20); and a light distribution element (30) that bends a light beam from the light source (20) toward the distance measurement target region (5) in a plurality of bending directions.

Description

Technical Field

[0001] The present invention relates to a light irradiation device, an optical distance measuring device and a vehicle. Background Art

[0002] An optical distance measuring device is a device that irradiates a light beam to a distance measuring target object and detects the light beam reflected by the distance measuring target object to measure the distance and direction to the distance measuring target object. In recent years, optical distance measuring devices using optical remote sensing technology such as LiDAR (Light Detection and Ranging) have been used.

[0003] For example, Patent Document 1 discloses a collision avoidance system that uses a guide light sensor mounted on a smartphone to measure the distance and direction to an object in front of it. Patent Document 2 discloses an omnidirectional distance measuring device that includes a plurality of radially arranged TOF sensors that measure distances based on the time of flight (TOF) of a light beam.

[0004] Prior art literature

[0005] Patent Literature

[0006] Patent Document 1: Japanese Patent Application Publication No. 2021-047143

[0007] Patent Document 2: Japanese Patent Application Publication No. 2021-099278 Summary of the invention

[0008] Problems to be solved by the invention

[0009] An optical distance measuring device equipped with a distance measuring sensor such as LiDAR generally comprises: a light irradiation device (transmitter) for irradiating a laser beam emitted from a light source to a distance measuring target object, and a light detection device (receiver) for detecting reflected light reflected from the distance measuring target object. In the optical distance measuring device, it is necessary to expand both the irradiation area of ​​the light beam of the light irradiation device (distance measuring target area) and the irradiation distance of the light beam (measurable distance).

[0010] However, when the power of the light source of the light irradiation device is fixed, the irradiation area and irradiation distance of the light beam are in a trade-off relationship. Therefore, it is not possible to extend the irradiation distance while expanding the irradiation area, and conversely, it is not possible to extend the irradiation distance while expanding the irradiation area. Therefore, as a solution to the problem of expanding both the irradiation area and the irradiation distance, a method is considered to scan (beam steering) the entire ranging target area by significantly reducing the irradiation area of ​​the light beam irradiated from the light irradiation device and sequentially switching the partially irradiated irradiation area within the ranging target area.

[0011] In this regard, many existing light irradiation devices for LiDAR use a lens unit for diffusing the irradiation light beam to achieve a wide range of irradiation areas and a short distance of irradiation. The lens unit is an optical device that combines a plurality of optical lenses and is capable of changing the irradiation direction of the light beam and the range of the irradiation area. The light irradiation device using the lens unit has high light beam control performance, but there is a problem of increased size and cost compared to the light irradiation device that does not use the lens unit. On the other hand, the light irradiation device that does not use the lens unit has the problem that light beam control cannot be performed in principle. That is, since the light beam from the light source irradiates substantially the entire area of ​​the ranging target area, the irradiation area cannot be reduced within the ranging target area, and light beam control cannot be achieved.

[0012] Therefore, the present invention has been made in view of the above-mentioned problems, and an object of the present invention is to realize light beam control so as to reduce the irradiation area within the distance measurement target area in a light irradiation device that does not use a lens unit.

[0013] Technical solutions to solve problems

[0014] In order to solve the above-mentioned problems, one embodiment of the present invention provides a light irradiation device, which is provided in an optical distance measuring device and irradiates a distance measuring target area with a light beam, and comprises:

[0015] Light source; and

[0016] A light distribution element is provided to bend a light beam from the light source toward the distance measurement target area in a plurality of bending directions.

[0017] It also includes a diffusion plate disposed between the light source and the distance measurement target area,

[0018] The diffusion plate is arranged to face the light distribution element.

[0019] The light source has a plurality of light emitting elements arranged one-dimensionally or two-dimensionally,

[0020] The light distribution element bends the plurality of light beams emitted from the plurality of light emitting elements in different bending directions.

[0021] The light irradiation device further includes a control unit that controls light emission of the plurality of light emitting elements.

[0022] The plurality of light emitting elements respectively correspond to a plurality of irradiation areas that divide the distance measurement target area one-dimensionally or two-dimensionally,

[0023] The plurality of light beams emitted from the plurality of light emitting elements are irradiated to the plurality of irradiation areas through the light distribution element and the diffusion plate respectively.

[0024] The control unit switches a light emitting element that emits light among the plurality of light emitting elements.

[0025] The light distribution element has a plurality of curved portions corresponding to the plurality of irradiation areas respectively.

[0026] The plurality of curved portions respectively bend the plurality of light beams emitted from the plurality of light emitting elements in different bending directions and guide the light beams to the plurality of irradiation areas.

[0027] The light distribution element is arranged between the light source and the diffusion plate.

[0028] The plurality of bent portions bend the plurality of light beams emitted from the plurality of light emitting elements in different bending directions and emit the light beams to the diffusion plate.

[0029] The diffusion plate diffuses the plurality of bent light beams incident from the plurality of bent portions, respectively, and irradiates the plurality of diffused light beams traveling in directions different from each other to the plurality of irradiation areas, respectively.

[0030] The light distribution element and the diffusion plate are arranged to be in contact with each other or to be joined via a joining member.

[0031] The light distribution element includes a curved element having a prism structure.

[0032] The prism structure is formed on surfaces of both sides of the bending element.

[0033] A first prism structure is formed on a surface of one side of the bending element, and a second prism structure is formed on a surface of the other side of the bending element.

[0034] The first prism structure and the second prism structure extend in directions intersecting with each other in a plan view.

[0035] The light distribution element includes a reflector.

[0036] The diffusion plate has a microlens array.

[0037] In order to solve the above-mentioned problems, another aspect of the present invention provides an optical distance measuring device, comprising:

[0038] the light irradiation device; and

[0039] A light detection device detects the light beam irradiated from the light irradiation device and reflected by the distance measurement target object.

[0040] In order to solve the above-mentioned problems, another aspect of the present invention provides a vehicle including the above-mentioned optical distance measuring device.

[0041] Effects of the Invention

[0042] According to the present invention, in a light irradiation device that does not use a lens unit, light beam control can be achieved to narrow the irradiation area within a distance measurement target area. BRIEF DESCRIPTION OF THE DRAWINGS

[0043] Figure 1 1 is a schematic diagram showing the overall structure of an optical distance measuring device according to a first embodiment of the present invention.

[0044] Figure 2 This is a schematic diagram showing a light irradiation device using a conventional lens unit.

[0045] Figure 3 This is a schematic diagram showing a light irradiation device using a conventional diffusion plate.

[0046] Figure 4 This is a schematic diagram showing a state in which the irradiation area is narrowed within the distance measurement target area by light beam control in a light irradiation device using a conventional lens unit.

[0047] Figure 5 It is a schematic diagram showing the light irradiation device according to the first embodiment of the present invention.

[0048] Figure 6 It is a schematic diagram showing the light beam control operation of the light irradiation device of this embodiment.

[0049] Figure 7 It is a plan view showing a light distribution element included in the light irradiation device according to this embodiment.

[0050] Figure 8 It is a partially enlarged perspective view showing a bending element having a prism structure according to this embodiment.

[0051] Fig. 9 yes Figure 7 XX and YY cross-sectional views of the bending element are shown.

[0052] Fig.10 It is a schematic diagram showing a structural example 1 of the light irradiation device according to this embodiment.

[0053] Fig.11 It is a schematic diagram showing a second structural example of the light irradiation device according to this embodiment.

[0054] Fig.12 It is a schematic diagram showing a structural example 3 of the light irradiation device according to this embodiment.

[0055] Fig.13 It is a schematic diagram showing a structural example 4 of the light irradiation device according to this embodiment.

[0056] Fig.14 It is a schematic diagram showing a structural example 5 of the light irradiation device according to this embodiment.

[0057] Fig.15 It is a schematic diagram showing a structural example 6 of the light irradiation device according to this embodiment.

[0058] Fig.16 This is a diagram showing the relative intensity distribution of the irradiation light beam when all six light emitting elements are simultaneously emitted (lit) in the light irradiation device according to the embodiment of the present invention.

[0059] Fig.17 This is a photograph showing the relative intensity distribution of the irradiation light beam when all six light emitting elements are simultaneously emitted (lit) in the light irradiation device of this embodiment.

[0060] Fig.18 This is a photograph showing the relative intensity distribution of the irradiation light beam when one light emitting element at the upper left among six light emitting elements in the light irradiation device of this embodiment is caused to emit light.

[0061] Fig.19 This is a photograph showing the relative intensity distribution of the irradiation light beam when one light emitting element at the upper center among six light emitting elements is caused to emit light in the light irradiation device of this embodiment.

[0062] Fig. 20 This is a photograph showing the relative intensity distribution of the irradiation light beam when one light emitting element at the upper right among six light emitting elements in the light irradiation device of this embodiment is caused to emit light. DETAILED DESCRIPTION

[0063] Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. The specific dimensions, materials, values, etc. shown in the embodiments are only for illustration to facilitate understanding of the invention, and do not limit the present invention except for the cases specifically described. In addition, in this specification and the accompanying drawings, for elements having substantially the same function and structure, repeated description is omitted by marking the same reference numerals, and elements that are not directly related to the present invention are omitted from the drawings.

[0064] [1. Overall structure of the optical distance measuring device]

[0065] First, refer to Figure 1 , the overall structure of the optical distance measuring device 1 according to the first embodiment of the present invention is described. Figure 1 1 is a schematic diagram showing the overall structure of the optical distance measuring device 1 according to the present embodiment.

[0066] like Figure 1As shown, the optical distance measuring device 1 of the present embodiment is a device that measures the distance and direction to the distance measuring target 6, the size and shape of the distance measuring target 6, etc. by irradiating a light beam to the distance measuring target area 5 and detecting the light beam reflected by the distance measuring target 6. The optical distance measuring device 1 is provided with a distance measuring sensor using remote sensing technology such as LiDAR. The distance measuring method of the optical distance measuring device 1 is preferably a TOF method that calculates the distance to the distance measuring target 6 by measuring the flight time (TOF) of the light beam, which is the round-trip time from the optical distance measuring device 1 emitting the irradiation light beam to receiving the reflected light beam. In addition, various distance measuring methods such as the triangulation distance measuring method can also be used.

[0067] The optical distance measuring device 1 of this embodiment can be applied to various technical fields using remote sensing. For example, the optical distance measuring device 1 can be applied to autonomous driving technology in the automotive field, ADAS (Advanced Driver-Assistance Systems) or radar devices for traffic control, measurements in the construction field, measurements using aircraft / satellites, vacuum cleaner robots, 3D mapping measurements in various terminal devices (smart phones, smart glasses, smart watches, personal computers, tablet computers, etc.) using technologies such as AR (augmented reality) / MR (mixed reality) / VR (virtual reality), various measurements such as geology / seismology / atmospheric physics / oceanography, or military uses, etc.

[0068] The optical distance measuring device 1 of this embodiment is mounted on a vehicle such as a car, a bus, a truck, a motorcycle, etc., and can be applied to autonomous driving technology or ADAS, etc. In this case, the optical distance measuring device 1 can measure the distance and direction of the distance measuring target 6 existing around the vehicle, especially in the space in front of the vehicle, and create a 3D map. However, the optical distance measuring device 1 is not limited to this example, and can be mounted on various products in the above-mentioned various technical fields.

[0069] like Figure 1 As shown, the optical distance measuring device 1 of this embodiment includes a light irradiation device 2 (transmitter), a light detection device 3 (receiver), and a controller 4. The optical distance measuring device 1 functions as a distance measuring sensor such as LiDAR.

[0070] The light irradiation device 2 is a device (emitter) for irradiating a light beam to the distance measurement target area 5. The light irradiation device 2 irradiates the distance measurement target area 5 with a light beam emitted from a light source. The light beam irradiated from the light irradiation device 2 can be, for example, a laser beam having a wavelength band such as near infrared, visible light, or ultraviolet light, but preferably a laser beam having a wavelength band of near infrared light that is invisible to the human eye (e.g., 850nm to 1550nm). The light source provided by the light irradiation device 2 is preferably a laser light source such as a semiconductor laser that emits a near infrared laser beam.

[0071] The light irradiation device 2 includes, for example, a light source having a light emitting element that emits a laser beam, an optical element that diffuses the laser beam (such as the diffusion plate 40 described later), a glass cover, a housing, etc. (none of which is shown in the figure). The light irradiation device 2 emits a pulsed laser beam from the light source, diffuses the laser beam using an optical element, and irradiates the diffused beam (irradiation beam) toward the distance measurement target area 5. The structure of the light irradiation device 2 will be described in detail later.

[0072] The light detection device 3 is a device (receiver) for detecting the light beam (reflected light beam) irradiated from the light irradiation device 2 and reflected by the ranging target 6. The light detection device 3 includes, for example, a glass cover, a filter, a light receiving unit including a light receiving element, etc. (none of which is shown in the figure). The filter cuts off the light beam other than the reflected light beam reflected by the ranging target 6 (for example, sunlight or illumination light, etc.) as noise, and only allows the light beam corresponding to the wavelength of the laser beam emitted from the light irradiation device 2 to pass. In this way, the detection sensitivity of the reflected light beam of the light receiving element can be improved. The light receiving element is composed of a photoelectric conversion element that generates a voltage by receiving the incident reflected light beam. The light receiving element is composed of an image sensor such as a CMOS (Complementary Metal Oxide Semiconductor) sensor and a CCD (Charge Coupled Device) sensor. The light receiving unit receives the reflected light beam from the ranging target 6, for example, by a plurality of light receiving elements arranged two-dimensionally on the light receiving surface, converts the light intensity at each pixel position of the light receiving surface into an electrical signal, and outputs it to the controller 4.

[0073] The controller 4 is an example of a control unit that controls the operation of the light irradiation device 2, the light detection device 3 and other various devices included in the optical distance measuring device 1. The controller 4 includes, for example, a processor, a memory, an input device, an output device, a communication device, etc. (none of which are shown).

[0074] The processor is composed of, for example, a CPU (Central Processing Unit) or other microprocessors. The processor executes a program stored in a memory or other storage medium. Thus, various processes in the optical distance measuring device 1 are performed, and various functions determined by the program can be realized.

[0075] Memory is a storage medium that stores programs and other various data. Memory includes, for example, RAM (Random Access Memory) and ROM (Read Only Memory). ROM is a non-volatile memory that stores programs used by the processor and data used to make the programs run. RAM is a volatile memory that temporarily stores data such as variables, operation parameters, and operation results used in the processing executed by the processor. The program stored in ROM is read into RAM and executed by a processor such as a CPU.

[0076] The controller 4 performs the ranging operation of the optical ranging device 1 by controlling the light irradiation device 2 and the light detection device 3. For example, the controller 4 repeatedly irradiates the laser beam of the light irradiation device 2 and detects the reflected light beam of the light detection device 3, and three-dimensionally scans the ranging target area 5 while making a three-dimensional map. At this time, the controller 4 calculates the distance and direction from the optical ranging device 1 to the ranging target 6 based on the time difference between the emission timing of the laser beam of the light irradiation device 2 and the detection timing of the reflected light beam of the light detection device 3 (i.e., the flight time of the light beam: TOF).

[0077] In this way, the optical distance measuring device 1 creates a three-dimensional map showing the distance and direction to the distance measuring target object 6 present in the distance measuring target area 5 by scanning the distance measuring target area 5 with a laser beam. For this reason, the optical distance measuring device 1 is required to irradiate the laser beam in as wide an angle range as possible (i.e., the field of view (FOV)). Since the diffusion of the laser beam emitted from the light source of the light irradiation device 2 becomes narrower, the field of view of the distance measuring sensor becomes narrower. Therefore, it is preferred to diffuse the laser beam using a diffusion plate or the like, and irradiate the diffused beam to the distance measuring target area 5 at a wide field of view to expand the irradiation area.

[0078] In order to diffuse the laser beam, the diffusion plate has a microlens array, and the desired diffusion angle (i.e., field angle) can be obtained by changing the shape of the microlens. However, as described above, in a distance measurement sensor such as a TOF sensor, the width of the irradiation area of ​​the laser beam (the horizontal and vertical range of the distance measurement target area 5) and the irradiation distance of the laser beam (the measurable distance) are in a trade-off relationship. Therefore, it is preferable to determine the width of the irradiation area by striking a balance between the two.

[0079] Therefore, the purpose of the optical distance measuring device 1 of this embodiment is to expand both the entire irradiation area (distance measuring target area 5) and the irradiation distance of the laser beam in the light irradiation device 2 using a diffuser to diffuse the laser beam. To this end, the present embodiment is characterized in that the distance measuring target area 5 is divided into a plurality of irradiation areas 7 (see the following description). Figure 5), by sequentially switching the irradiation area 7 of the distance measurement target area 5 that is partially irradiated with the laser beam, it is possible to perform beam control to scan the distance measurement target area 5 (refer to the following Figure 6 ).

[0080] [2. Details of background technology]

[0081] Next, before describing the light irradiation device 2 of this embodiment in detail, Figure 2 to Figure 5 As background technology of the light irradiation device 2 (emitter) of the present embodiment, a conventional light irradiation device 2 ′ and the structure and problems of the light irradiation device 2 ′ are described in detail. Figure 2 1 is a schematic diagram showing a light irradiation device 2 ′ using a conventional lens unit 14 . Figure 3 It is a schematic diagram showing a light irradiation device 2 ′ using a conventional diffusion plate 16 .

[0082] like Figure 2 As shown, the light irradiation device 2' includes a light source 10 and a lens unit 14, the light source 10 has a plurality of light emitting elements 11 that emit laser beams, and the lens unit 14 diffuses the laser beam emitted from the light source 10. The lens unit 14 is an optical device composed of a combination of a plurality of optical lenses, etc. The lens unit 14 can diffuse the laser beam incident from the light source 10 at a desired diffusion angle, thereby enlarging or reducing the irradiation area 7. In addition, the lens unit 14 can bend the laser beam incident from the light source 10 at a desired bending angle to move the irradiation area 7 within the distance measurement target area 5.

[0083] In addition, if Figure 3 As shown, the light irradiation device 2' includes a light source 10 and a diffusion plate 16, the light source 10 has a plurality of light emitting elements 11 that emit laser beams, and the diffusion plate 16 diffuses the laser beam from the light source 10. A microlens array is formed on the surface of the diffusion plate 16. The diffusion plate 16 can diffuse the laser beam incident from the light source 10 at a predetermined diffusion angle corresponding to the shape of the microlens. In addition, when designing the diffusion plate 16, the diffusion angle of the laser beam of the diffusion plate 16 can be adjusted by changing the shape of the microlens, but after the diffusion plate 16 is manufactured, the diffusion angle cannot be changed.

[0084] In these conventional light irradiation devices 2', 2', the laser beam diffused by the lens unit 14 or the diffuser plate 16 is irradiated toward the distance measurement target area 5. In the distance measurement target area 5, the area actually irradiated with the diffused laser beam (irradiation beam) is the irradiation area 7. Figure 2 , Figure 3 In the example shown in FIG. 1 , the irradiation area 7 is a horizontally long, substantially rectangular area.

[0085] Here, yes Figure 2 , Figure 3The problems of the conventional light irradiation devices 2' and 2' shown in the following will be described. Figure 2 The light irradiation device 2' of the lens unit 14 shown can enlarge or reduce the size of the irradiation area 7 in the distance measurement target area 5, or shift the irradiation area 7 in the distance measurement target area 5 by changing the configuration or orientation of the optical lens in the lens unit 14. Therefore, the light irradiation device 2' can perform beam control for scanning the distance measurement target area 5 with the irradiation beam by reducing the irradiation area 7 to a part of the distance measurement target area 5 and switching the irradiation area 7 of the part in sequence. However, Figure 2 The light irradiation device 2' of the lens unit 14 shown in the figure needs to set a movable mechanism or a driving mechanism of the optical lens in the lens unit 14, or set a lens unit 14 with multiple optical lenses, so it is different from the one with Figure 3 Compared with the light irradiation device 2' with the diffuser plate 16 shown in the figure, there is a problem that the device size and cost are increased. In recent years, although miniaturization of light irradiation devices is required, miniaturization of the light irradiation device 2' including the lens unit 14 is limited.

[0086] In addition, in the Figure 2 In the light irradiation device 2' of the lens unit 14 shown in the figure, there is also a problem that a non-irradiated portion is generated when a part of the light source 10 is damaged. Figure 4 As shown, consider the case where each light emitting element 11 of the light source 10 is composed of a vertical cavity surface emitting laser (VCSEL: Vertical Cavity Surface Emitting Laser), and the light source 10 is composed of a VCSEL array. In addition, Figure 4 The light irradiation device 2' having the lens unit 14 is schematically shown in a state where the irradiation area 7e is narrowed in the distance measurement target area 5 by light beam control. Figure 4 In the example of FIG. 1 , the light emitting element 11 composed of VCSEL has 9 mesas 12 arranged vertically and horizontally (3 rows and 3 columns) on the light emitting surface. Here, if one of the 9 mesas 12 in the middle is damaged and does not emit light, as shown in FIG. Figure 4 As shown, in the irradiation area 7e irradiated from the light emitting element 11 including the broken table 12, an unirradiated portion is generated in the form of a lack of the central portion thereof. Thus, when the light beam of the irradiation area 7 is controlled using the light irradiation device 2' having the lens unit 14, it is impossible to cope with the failure of the light emitting element 11 which is a part of the light source 10, and there is also a problem of generating an unirradiated portion (i.e., an unmeasurable area) in the irradiation area 7e.

[0087] On the other hand, in the Figure 3In the light irradiation device 2' having the diffuser plate 16 shown, the positional relationship between the light source 10 and the diffuser plate 16 is fixed, and the diffusion angle of the diffuser plate 16 is also constant. Therefore, when the laser beam diffused by the diffuser plate 16 is irradiated to the distance measurement target area 5, the range of the irradiation area 7 cannot be reduced or moved within the distance measurement target area 5. Therefore, in the light irradiation device 2' having the diffuser plate 16, since it is not possible to perform beam control in principle, there is a problem that both the range of the irradiation area 7 and the irradiation distance cannot be expanded by beam control.

[0088] As mentioned above, there is currently a use as mentioned above Figure 2 The light irradiation device 2' using the lens unit 14 shown in the figure has the problem of increased device size and cost, and the problem of an unirradiated portion when a part of the light source 10 is damaged. Therefore, in order to solve the problem of the light irradiation device 2' using the lens unit 14, it is required to use a light irradiation device using a diffuser plate that does not cause the problem, and in the light irradiation device using the diffuser plate, it is required to be able to perform beam control.

[0089] Therefore, in the present embodiment, in the light irradiation device 2 using the diffusion plate, a method is adopted that can divide the distance measurement target area 5 into a plurality of irradiation areas 7a to 7f (see Figure 5 ), and a structure of light beam control for scanning the distance measurement target area 5 by partially irradiating each of the divided irradiation areas 7a to 7f with a diffuse light beam. In this light beam control, the entire distance measurement target area 5 is scanned by sequentially partially irradiating each of the divided irradiation areas 7a to 7f with a light beam. Through this light beam control, both the range of the distance measurement target area 5 (the total range of the divided multiple irradiation areas 7a to 7f) and the irradiation distance of the light beam can be expanded. Hereinafter, a structure for performing light beam control in the light irradiation device 2 of this embodiment will be described in detail.

[0090] [3. Structure of light irradiation device]

[0091] Next, refer to Figure 5 to Figure 7 , the structure of the light irradiation device 2 (emitter) of this embodiment is described. Figure 5 It is a schematic diagram showing the light irradiation device 2 according to the present embodiment.

[0092] Figure 6 It is a schematic diagram showing the light beam control operation of the light irradiation device 2 according to the present embodiment. Figure 7 It is a plan view showing the light distribution element 30 (bending element 31 ) included in the light irradiation device 2 according to the present embodiment.

[0093] like Figure 5 As shown, the light irradiation device 2 of the present embodiment includes a light source 20 , a light distribution element 30 , a diffusion plate 40 , and a control unit 50 .

[0094] The diffuser plate 40 is disposed between the light source 20 and the distance measurement target area 5. The light distribution element 30 is disposed between the light source 20 and the distance measurement target area 5 and is disposed opposite to the diffuser plate 40. Figure 5 In the example of FIG. 5 , the light distribution element 30 is disposed between the light source 20 and the diffuser plate 40 , but the present invention is not limited to this example. The light distribution element 30 may also be disposed between the diffuser plate 40 and the distance measurement target area 5 .

[0095] The light source 20 is a device for generating and emitting a light beam for irradiating the ranging target area 5. As described above, the light beam emitted by the light source 20 can be, for example, a laser beam having a wavelength band such as near infrared, visible light, or ultraviolet light, but preferably a laser beam having a wavelength band of near infrared light invisible to the human eye (e.g., 850nm to 1550nm).

[0096] The light source 20 is, for example, a surface light source including a plurality of light emitting elements 21a to 21f (hereinafter sometimes collectively referred to as “light emitting elements 21”) that emit a plurality of laser beams 51a to 51f (hereinafter sometimes collectively referred to as “laser beams 51”). Figure 5 As shown, each light emitting element 21 of the light source 20 is composed of a surface-emitting semiconductor laser, such as a vertical cavity surface emitting laser (VCSEL). The light source 20 is composed of, for example, a VCSEL array composed of a plurality of VCSELs. The plurality of light emitting elements 21 are arranged in a one-dimensional or two-dimensional manner on the light emitting surface 22 of the light source 20. Figure 5 In the example, six light-emitting elements 21a to 21f composed of VCSELs are arranged two-dimensionally vertically and horizontally (for example, 2 rows and 3 columns) on the light-emitting surface 22 of the light source 20. However, the two-dimensional arrangement direction of the plurality of light-emitting elements 21 is not limited to the two vertical and horizontal directions, but may also be two directions intersecting in the oblique direction. In addition, the plurality of light-emitting elements 21 may also be arranged one-dimensionally along any direction (for example, 1 row and 6 columns or 6 rows and 1 column, etc.). In addition, the number of light-emitting elements 21 is not limited to the 6 examples shown in the figure, but may be any number greater than 2.

[0097] The plurality of light emitting elements 21a to 21f emit a plurality of mutually parallel laser beams 51a to 51f toward the light distribution element 30. Figure 5 In the example, six light emitting elements 21a to 21f respectively emit six laser beams 51a to 51f toward the light distribution element 30. The optical axes of the plurality of laser beams 51a to 51f are parallel to each other. The laser beams 51 emitted from these light emitting elements 21 may be, for example, diffuse beams or collimated parallel beams. However, in order to extend the irradiation distance of the laser beams 51, the Figure 6The beam control shown can be achieved with respect to a farther distance measurement target area 5, preferably a diffuse beam as close to a parallel beam as possible. In addition, in this embodiment, a laser light source having an LD (Laser Diode) that emits a laser beam 51 is used as the light source 20, but it is not limited to this example. The light source can be a light source having other light-emitting elements such as an LED (Light Emitting Diode) or a lamp.

[0098] In the following description, the optical axis direction of the laser beam 51 emitted from the light emitting element 21 is referred to as the "Z direction", the horizontal direction in a plane perpendicular to the "Z direction" is referred to as the "X direction", and the vertical direction in the plane is referred to as the "Y direction". The Z direction is a direction perpendicular to the light emitting surface 22 of the light source 20. The XY plane is a plane parallel to the light emitting surface 22. The X direction is a horizontal direction in the light emitting surface 22 of the light source 20, and the Y direction is a vertical direction in the light emitting surface 22 of the light source 20.

[0099] Each light emitting element 21a to 21f can be turned on (emit light) and off (not emit light) independently of each other. Thus, only some of the light emitting elements 21a to 21f can be turned on, and the other light emitting elements 21 can be turned off. The turning on and off of the light emitting elements 21 is controlled by the control unit 50.

[0100] The control unit 50 controls the operation of each part of the light irradiation device 2. The control unit 50 may be constituted by, for example, a dedicated processor provided in the light irradiation device 2, or may be constituted by the controller 4 (see Figure 1 ) and the like. The control unit 50 has a function of controlling the light emission of the plurality of light emitting elements 21 of the light source 20. The control unit 50 controls the light beam control operation of the light irradiation device 2 by switching the light emitting elements among the plurality of light emitting elements 21. For example, when executing Figure 6 In the light beam control shown, the control unit 50 sequentially switches the light emitting elements 21 that are turned on (emitting light) among the plurality of light emitting elements 21 in accordance with a preset order.

[0101] like Figure 5 and Figure 6 As shown, the plurality of light emitting elements 21a to 21f included in the light source 20 correspond to a plurality of irradiation areas 7a to 7f (hereinafter sometimes collectively referred to as “irradiation areas 7”) that divide the distance measurement target area 5 into one-dimensional or two-dimensional areas.

[0102] exist Figure 5In the example of , the irradiation area 7 in the ranging target area 5 is divided into 6 irradiation areas 7a to 7f. The 6 irradiation areas 7a to 7f are divided two-dimensionally into vertical and horizontal directions (for example, 2 rows and 3 columns) in the ranging target area 5. However, similar to the arrangement of the above-mentioned light-emitting elements 21, the two-dimensional arrangement direction of the divided multiple irradiation areas 7a to 7f is not limited to the two vertical and horizontal directions, but can also be two directions intersecting in the oblique direction. In addition, the multiple irradiation areas 7a to 7f can also be arranged one-dimensionally along any direction (for example, 1 row and 6 columns, or 6 rows and 1 column, etc.).

[0103] Next, the light distribution element 30 will be described. The light distribution element 30 is an optical element for bending the light beam from the light source 20 toward the distance measurement target area 5 in a plurality of bending directions at different bending angles α. The light distribution element 30 distributes light in a manner that expands the light beam toward the distance measurement target area 5 by bending the light beam from the light source 20 in a plurality of bending directions. The light distribution element 30 is composed of an optical element having a function of bending a light beam. For example, the light distribution element 30 is composed of a bending element 31 having tiny prism structures 37 and 38 on the surface (see Figure 7 to Figure 11 ), multiple reflectors 32 (refer to Fig.12 ), a plurality of prisms 33 (refer to Fig.15 ) or a combination of these optical elements (refer to Fig.13 , Fig.14 ) and so on. Figure 5 , the light distribution element 30 is an example of a bending element 31 having prism structures 37 and 38. The specific structure of the optical elements (bending element 31, reflector 32, prism 33, etc.) constituting the light distribution element 30 will be described later.

[0104] The light distribution element 30 is disposed opposite to the diffusion plate 40. Figure 5 In the example, the light distribution element 30 is interposed between the light source 20 and the diffuser 40, and is arranged opposite to the surface on the light source 20 side of the two surfaces of the diffuser 40. However, the light distribution element 30 may be arranged closer to the distance measurement target area 5 than the diffuser 40, and be arranged opposite to the surface on the distance measurement target area 5 of the two surfaces of the diffuser 40.

[0105] exist Figure 5In the example, for ease of explanation, the light distribution element 30 and the diffuser plate 40 are shown as being separated from each other, but the light distribution element 30 and the diffuser plate 40 are preferably configured in contact with each other. Alternatively, the light distribution element 30 and the diffuser plate 40 are preferably joined via a joining member (such as an adhesive material, a double-sided tape, etc.) not shown in the figure, and are configured close to each other. As a result, the light distribution element 30 and the diffuser plate 40 can be brought close to each other, and the total size of the light distribution element 30 and the diffuser plate 40 can be reduced, so that the light irradiation device 2 can be miniaturized. In addition, similarly, from the perspective of miniaturizing the light irradiation device 2, it is preferred that the light distribution element 30 and the light source 20 are configured in contact with each other or close to each other.

[0106] The light distribution element 30 has a function of bending the plurality of laser beams 51 emitted from the plurality of light emitting elements 21 of the light source 20 in different bending directions. Specifically, the light distribution element 30 bends the plurality of laser beams 51a to 51f emitted from the plurality of light emitting elements 21 in different bending directions at different bending angles αa to αf (hereinafter sometimes collectively referred to as "bending angle α"). The bending angle α is the bending angle α. X and the bending angle α Y The resultant angle. Bending angle α X is the bending angle in the X direction, the bending angle α Y is the bending angle in the Y direction. In addition, the bending direction is the traveling direction of the light beam 52 bent by the light distribution element 30 .

[0107] For example, Figure 5 As shown in FIG. 1 , the light distribution element 30 causes the laser beam 51b emitted from the light emitting element 21b disposed at the upper center of the light source 20 to be bent upward in the Y direction at a predetermined angle α. Y b, and does not bend in the X direction. In addition, the light distribution element 30 causes the laser beam 51e emitted from the light emitting element 21e disposed at the lower center of the light source 20 to be bent at a predetermined angle α in the downward direction in the Y direction. Y e bends, not bends in the X direction. Here, for example, "α Y b=+12.5°、α Y e=-12.5°","α X b=α X e=0°”.

[0108] The laser beam 51b bent by the light distribution element 30 becomes a bent beam 52b. The bent beam 52b is light that is bent upward relative to the traveling direction (Z direction) of the laser beam 51b and travels in the bending direction. The angular difference between the optical axis of the bent beam 52b and the optical axis of the laser beam 51b is the bending angle α. Yb. On the other hand, the laser beam 51e bent by the light distribution element 30 becomes a bent beam 52e. The bent beam 52e is a beam that travels in a bent direction that is bent downward relative to the traveling direction (Z direction) of the laser beam 51e. The angle difference between the optical axis of the bent beam 52e and the optical axis of the laser beam 51e is a bending angle α. Y e.

[0109] In this way, in order to bend the laser beams 51a to 51f from the plurality of light emitting elements 21a to 21f in mutually different bending directions, as shown in FIG. Figure 7 As shown, the light distribution element 30 has a plurality of bent portions 35 a to 35 f (hereinafter sometimes collectively referred to as “bent portions 35 ”).

[0110] like Figure 5 and Figure 7 As shown, for example, the light distribution element 30 is composed of a curved element 31 having a prism structure (for example, a light guide plate having a prism structure formed on the surface). In this case, the plurality of curved portions 35 correspond to the respective regions when the flat curved element 31 is divided into a plurality of regions in the X and Y directions. Figure 5 and Figure 7 In the example of , the bending element 31 is composed of six bending parts 35a to 35f, and each bending part 35a to 35f corresponds to each area when the rectangular flat plate-shaped bending element 31 is divided into six areas. The six bending parts 35a to 35f are divided two-dimensionally into vertical and horizontal areas (for example, 2 rows and 3 columns) on the surface of the bending element 31.

[0111] The plurality of curved portions 35a to 35f of the light distribution element 30 (curved element 31) respectively correspond to the plurality of light emitting elements 21a to 21f of the light source 20. The plurality of curved portions 35a to 35f also respectively correspond to the plurality of divided irradiation areas 7a to 7f.

[0112] Furthermore, the plurality of bending portions 35a to 35f have the function of bending the incident light at different bending angles αa to αf. Therefore, the plurality of bending portions 35a to 35f can respectively bend the laser beams 51a to 51f incident from the plurality of light emitting elements 21a to 21f of the light source 20 in different bending directions and guide them toward the plurality of different irradiation areas 7a to 7f.

[0113] For example, Figure 5 As shown in FIG. 1 , the laser beam 51b emitted from the light emitting element 21b is bent at the above-mentioned bending angle α when passing through the bent portion 35b of the light distribution element 30. Yb is bent upward in the Y direction to become a bent beam 52b. The bent beam 52b is the laser beam 51 that travels along the first bending direction that is set in advance. Then, the bent beam 52b is diffused when passing through the diffuser plate 40 to become a diffused beam 53b, which partially irradiates the irradiation area 7b. On the other hand, the laser beam 51e emitted from the light emitting element 21e is bent at the above-mentioned bending angle α when passing through the curved portion 35e of the light distribution element 30. Y e is bent downward in the Y direction to become a bent beam 52e. The bent beam 52e is a laser beam traveling in a second bent direction different from the first bent direction. Then, the bent beam 52e is diffused when passing through the diffuser plate 40 to become a diffused beam 53e, which partially irradiates the irradiation area 7e.

[0114] In addition, similar to the arrangement of the light emitting elements 21, the two-dimensional arrangement direction of the divided multiple curved portions 35 is not limited to the two longitudinal and transverse directions, but may be two directions intersecting in the oblique direction. In addition, the multiple curved portions 35a to 35f may be arranged one-dimensionally (for example, 1 row and 6 columns or 6 rows and 1 column, etc.) along any direction.

[0115] In addition, Figure 5 and Figure 7 In the example shown, a plurality of curved portions 35 having different bending functions are integrally formed as one curved element 31. Thus, since the light distribution element 30 can be formed by one curved element 31, there are advantages that the number of components of the light distribution element 30 can be reduced, the size of the light distribution element 30 can be reduced, and the handling of the light distribution element 30 becomes easy. However, the present invention is not limited to such an example, and for example, a plurality of curved portions 35 may be separately formed using different curved elements.

[0116] Next, the diffuser plate 40 will be described. The diffuser plate 40 has a function of diffusing the laser beam (bent beam 52) incident from the light distribution element 30. That is, the diffuser plate 40 diffuses the plurality of bent beams 52 incident from the light distribution element 30 at a predetermined diffusion angle β, and emits a plurality of diffused beams 53.

[0117] The diffuser plate 40 has, for example, a flat plate shape or a curved plate shape. Figure 5 The diffuser plate 40 shown has, for example, a rectangular flat plate shape. The shape and thickness of the diffuser plate 40 may be any shape and thickness depending on the shape and structure of the light irradiation device 2 to which the diffuser plate 40 is mounted. The surface area of ​​the diffuser plate 40 is preferably larger than the area of ​​the light distribution element 30. Thus, all of the plurality of bent light beams 52 that are bent and diffused in a plurality of bending directions by the light distribution element 30 can be incident on the diffuser plate 40.

[0118] The diffuser plate 40 includes a film-shaped or plate-shaped substrate 41 and a microlens array 42 formed on the surface of the substrate 41 .

[0119] The substrate 41 is formed of a transparent material that can transmit light. For example, the substrate 41 can also be formed of a material with a light transmittance of 70% or more in the near-infrared band. The substrate 41 is formed of, for example, known resins such as polymethylmethacrylate (PMMA), polyethylene terephthalate (PET), polycarbonate (PC), cycloolefin copolymer (COC), cycloolefin polymer (COP), triacetylcellulose (TAC), or other materials. Alternatively, the substrate 41 can also be formed of known glass materials such as quartz glass, borosilicate glass, and whiteboard glass, or other inorganic materials.

[0120] The microlens array 42 is disposed on at least one surface (main surface) of the substrate 41. The microlens array 42 is a collection of multiple microlenses arranged on the surface of the substrate 41. The microlens is, for example, a microscopic optical lens of the order of tens of μm. The microlens is composed of a convex structure (convex lens) or a concave structure (concave lens) having a light diffusion function, for example, having an opening width (lens diameter) of about tens of μm and a curvature radius of about tens of μm. The surface shape of the microlens can be a spherical shape or an aspherical shape. In addition, the surface shapes of the multiple microlenses can be uniform shapes or random shapes that are different from each other. In addition, the microlenses can be regularly arranged on the surface of the substrate 41 or randomly configured. By changing the surface shape and configuration of the microlens, the diffusion angle β when the light beam is diffused by the diffuser 40 can be adjusted.

[0121] In the diffuser plate 40 of the present embodiment, for example, a plurality of microlenses are formed with a substantially uniform surface shape and arrangement on the entire surface of the substrate 41. Thus, no matter where the bent light beam 52 from the light distribution element 30 is incident on the surface of the diffuser plate 40, the diffuser plate 40 diffuses the bent light beam 52 at a substantially uniform diffusion angle β and emits a diffused light beam 53. However, the present invention is not limited to this example, and the surface of the diffuser plate 40 may be divided into a plurality of regions, and the surface shape of the microlens array 42 of the diffuser plate 40 may be changed for each region in such a manner that the diffusion angle β varies for each region. Thus, the diffusion angle β can be made different for each region of the diffuser plate 40, and the diffusion angles βa to βf of the plurality of diffused light beams 53a to 53f emitted from the diffuser plate 40 can be adjusted respectively. Therefore, the degree of freedom of light beam control using the light distribution element 30 and the diffuser plate 40 can be further improved.

[0122] [4. Beam control operation]

[0123] The configurations of the light source 20, the light distribution element 30, the diffuser plate 40, and the control unit 50 of the light irradiation device 2 of the present embodiment have been described above. Figure 5 and Figure 6 , the light beam control operation of the light irradiation device 2 of this embodiment is described.

[0124] According to the light irradiation device 2 of the present embodiment, the plurality of laser beams 51a to 51f emitted from the plurality of light emitting elements 21a to 21f of the light source 20 are locally irradiated to the plurality of irradiation areas 7a to 7f in the distance measurement target area 5 through the light distribution element 30 and the diffusion plate 40 .

[0125] At this time, the plurality of curved portions 35a to 35f of the light distribution element 30 respectively bend the plurality of laser beams 51a to 51f incident from the plurality of light emitting elements 21a to 21f in mutually different bending directions, and emit the bent light beams 52a to 52f toward the diffuser 40. Due to the light distribution function of the light distribution element 30, the plurality of bent light beams 52a to 52f bent by the light distribution element 30 become a light beam that diffuses the plurality of laser beams 51a to 51f as a whole. The diffuser 40 diffuses the plurality of bent light beams 52a to 52f incident from the plurality of curved portions 35a to 35f of the light distribution element 30, respectively. Then, the diffuser 40 irradiates the plurality of diffused light beams 53a to 53f traveling in mutually different directions to the plurality of irradiation areas 7a to 7f in the distance measurement target area 5, respectively. Here, the irradiation areas 7a to 7f are areas that divide the distance measurement target area 5, and the area of ​​each irradiation area 7a to 7f is smaller than the area of ​​the entire distance measurement target area 5. By combining the above-mentioned plurality of irradiation areas 7 a to 7 f , it is possible to cover the entirety or most of the distance measurement target area 5 .

[0126] For example, in Figure 5 In the example shown, the range of the distance measurement target area 5 is considered to be the field angle θ in the horizontal direction (X direction) (refer to Figure 6 ) is 90°, the vertical (Y) field of view (Refer to Figure 6 ) is the range represented by 50° Furthermore, the diffusion angle β of the diffuser plate 40 in the horizontal direction (X direction) is X The diffusion angle β in the vertical direction (Y direction) is 30°. Y It is 25°(30°×25°).

[0127] At this time, the bending angles α in the X direction of the two bent portions 35a and 35d on the left side in the X direction of the light distribution element 30 are X a、α X d(refer to Fig. 9 ) is set to -30°, and the bending angles α of the two bending portions 35c and 35f on the right side in the X direction are X c. α X f(ref Fig. 9 ) is set to +30°, and the bending angles α in the X direction of the two central bending portions 35b and 35e in the X direction are set to +30°. X b. α X e may be set to ±0°. In addition, the Y-direction bending angles α of the three bending portions 35a to 35c on the upper side of the light distribution element 30 are Y a、α Y b. α Y c is set to +25°, and the Y-direction bending angles α of the three bent portions 35d to 35f on the lower side of the Y direction are set to Y d、α Y e、α Y f can be set to -25°. Thus, in the entire light distribution element 30, the optical axis of the laser beam 51 from the six light emitting elements 21 of the light source 20 can be bent within a bending range of (30°×25°). Therefore, by combining the bending range (30°×25°) of the light distribution element 30 and the diffusion range (30°×25°) of the diffusion plate 40, the range of the above-mentioned distance measurement target area 5 can be covered.

[0128] In this way, the field angle θ of the distance measurement target area 5 is The relationship between the light distribution element 30 and the diffuser plate 40 is expressed by the following equations (1) to (6). In the following equations, the values ​​in parentheses are Figure 5 as well as Fig. 9 , Fig.10 Specific numerical values ​​of each parameter in the case of the structural example shown.

[0129] <X - direction>

[0130] θ = β X ×n X …(1)

[0131] α Xk =(θ / n X )×m Xk …(2)

[0132] (θ = 90°, β X = 30°, n X = 3, m Xk = - 1, 0, + 1)

[0133] 0° < γ X < β X ···(3)

[0134] Wherein,

[0135] θ: represents the field - of - view angle of the irradiation range in the X - direction of the ranging target area 5

[0136] β X : the diffusion angle of the diffusion plate 40 in the X - direction

[0137] n X : the number of light - emitting elements 21 arranged in the X - direction

[0138] α Xk : the bending angle in the X - direction of each bending portion 35 of the light - distribution element 30

[0139] m Xk : represents the ordinal number of the ± k - th light - emitting element 21 arranged in the X - direction with respect to the light - emitting element 21 arranged at the center in the X - direction (for example, for the light - emitting element 21a arranged at the - 1st position, m Xa is "-1", for the light - emitting element 21b arranged at the 0th position, m Xb is "0", and for the light - emitting element 21c arranged at the + 1st position, m Xc is "+1".)

[0140] γ X : the diffusion angle in the X - direction of the entire light beam emitted from the light source 20

[0141] <Y - direction>

[0142]

[0143]

[0144]

[0145] Wherein,

[0146] : The field of view angle representing the irradiation range in the Y direction of the ranging target area 5

[0147] β Y : Diffusion angle of the diffuser plate 40 in the Y direction

[0148] n Y : The number of light emitting elements 21 arranged in the Y direction

[0149] α Yk : The bending angle of each bent portion 35 of the light distribution element 30 in the Y direction

[0150] m Yk : represents the ordinal number of the ±kth light emitting element 21 arranged in the Y direction with respect to the light emitting element 21 arranged in the center of the Y direction (for example, the m of the light emitting element 21a arranged in the +1st direction is Ya is "+1", and the m of the light emitting element 21d arranged at -1 is Yd is "-1". )

[0151] γ Y : The diffusion angle of the entire light beam emitted from the light source 20 in the Y direction

[0152] Then, if Figure 6 As shown, the control unit 50 performs a light beam control operation on the distance measurement target area 5 by switching the light emitting elements to be lit (emitting light) among the plurality of light emitting elements 21 a to 21 f of the light source 20 .

[0153] like Figure 6 As shown, first, the light emitting element 21a arranged at the upper left is turned on toward the light emitting surface 22 of the light source 20, and the other light emitting elements 21b to 21f are turned off. As a result, only the laser beam 51a emitted from the light emitting element 21a is guided to the irradiation area 7a at the upper right part of the distance measurement target area 5 via the above-mentioned light distribution element 30 and the diffusion plate 40, and only the irradiation area 7a is irradiated with the diffused light beam 53a. At this time, the diffused light beams 53b to 53f are not irradiated to the other irradiation areas 7b to 7e.

[0154] Next, when the light emitting element 21a is turned off and only the light emitting element 21b arranged at the upper center of the light emitting surface 22 of the light source 20 is turned on, the diffused light beam 53b is irradiated only to the irradiation area 7b at the upper center of the distance measuring target area 5. Thereafter, if the light emitting element 21b is turned off and only the light emitting element 21c arranged at the upper right is turned on toward the light emitting surface 22 of the light source 20, the diffused light beam 53c is irradiated only to the irradiation area 7c at the upper left of the distance measuring target area 5. Similarly, for the light emitting elements 21d, 21e, and 21f, by repeating the same switching action of turning on and off, the diffused light beams 53d, 53e, and 53f are sequentially irradiated to the irradiation areas 7d, 7e, and 7f of the distance measuring target area 5.

[0155] In this way, in the light irradiation device 2 of the present embodiment, the lighting and extinguishing of the plurality of light emitting elements 21a to 21f of the light source 20 are switched sequentially. As a result, the irradiation areas 7a to 7f that partially irradiate the diffused light beams 53a to 53f in the distance measurement target area 5 are switched sequentially. That is, in the distance measurement target area 5, the diffused light beams 53 are partially irradiated one area at a time in the order of the irradiation areas 7a, 7b, 7c, 7d, 7e, and 7f. In this way, it is possible to perform a beam control operation of scanning the wide range of the distance measurement target area 5 with each narrow range of the irradiation areas 7a to 7f.

[0156] In the light irradiation device 2 of the present embodiment, through the beam control operation, although the diffuser 40 is used, each laser beam 51a to 51f emitted from each light emitting element 21a to 21f can partially and concentratedly irradiate the irradiation area 7a to 7f of a part of the distance measurement target area 5. Therefore, according to the present embodiment, since any one of the narrow irradiation areas 7a to 7f can be irradiated concentratedly, it is different from the light irradiation device 2' (see the conventional light irradiation device 2') using the diffuser 16 described above. Figure 3 ), the irradiation distance from the light irradiation device 2 to the distance measurement target area 5 can be increased. Furthermore, by increasing the number of light emitting elements 21 provided on the light source 20 and the number of irradiation areas 7 in the distance measurement target area 5 in the X and Y directions, or increasing the bending angle α and the diffusion angle β, the range of the distance measurement target area 5 that can be irradiated with the light beam can be expanded. Therefore, in the light irradiation device 2 using the diffusion plate 40, both the irradiation range and the irradiation distance of the light beam can be expanded, and the measurable distance space can be expanded compared to the prior art.

[0157] In addition, the light irradiation device 2 of this embodiment has a simple diffusion structure that uses a diffusion plate 40 to diffuse the light beam. Therefore, it is different from the light irradiation device 2' (see FIG. 1 ) using the conventional lens unit 14. Figure 2 ) can significantly reduce the size and cost of the light irradiation device 2. In addition, even if a portion of the plurality of mesas provided by each light emitting element 21 is damaged or fails (see Figure 4 ), by diffusing the light beam emitted from the surrounding undamaged table surface on the diffusion plate 40, the irradiation area corresponding to the damaged table surface can also be covered. Therefore, unlike the light irradiation device 2' using the conventional lens unit 14, there will be no unirradiated portion in the irradiation area 7e (see Figure 4 ), so it is possible to prevent the generation of an unmeasurable area due to damage or failure of the light emitting element 21. Therefore, when the light irradiation device 2 of the present embodiment is used to control the light beam of the irradiation area 7, it is possible to cope with the damage or failure of the light emitting element 11 that is a part of the light source 10, and it is possible to prevent the generation of an unirradiated portion (i.e., an unmeasurable area) in the ranging target area 5.

[0158] In addition, Figure 6 In the light beam control operation shown, the lighted light emitting elements 21 and the irradiation areas 7 are switched one by one in sequence, but the example is not limited thereto, and two or more of the light emitting elements 21 can be simultaneously lit, and a plurality of diffuse light beams 53 can be simultaneously irradiated to a plurality of irradiation areas 7, and the lighted light emitting elements 21 and the plurality of irradiation areas 7 can be switched in sequence at the same time. For example, the lighting and extinguishing of one or more light emitting elements 21 can be switched from the light emitting elements 21 arranged on the left and right sides of the light emitting surface 22 of the light source 20 to the light emitting element 21 arranged in the center. Thus, the light beam control in which the irradiation area 7 is reduced in the distance measurement target area 5 can also be performed.

[0159] [5. Structure of light distribution element]

[0160] Next, refer to Figure 7 to Figure 9 , an example in which the light distribution element 30 provided in the light irradiation device 2 of the present embodiment is a bending element 31 having prism structures 37 and 38 will be described in detail. Figure 8 It is a partially enlarged perspective view showing a bending element 31 having prism structures 37 and 38 according to the present embodiment. Fig. 9 yes Figure 7 The bending element 31 is shown in XX and YY cross-sectional views.

[0161] like Figure 7 to Figure 9 As shown in FIG. 1 , the light distribution element 30 of this embodiment can be composed of a bending element 31 (for example, a prism sheet) having prism structures 37 and 38 for bending an incident light beam. The bending element 31 can be in any shape, such as a flat plate shape, a curved plate shape, or a block shape. Figure 7 The bending element 31 shown has, for example, a rectangular flat plate shape. The shape and thickness of the bending element 31 may be any shape and thickness depending on the shape and structure of the light irradiation device 2 to which the bending element 31 is mounted. The surface area of ​​the bending element 31 is preferably larger than the area of ​​the light emitting surface 22 of the light source 20. Figure 5All laser beams 51 emitted from the plurality of light emitting elements 21 of the light source 20 can be incident on the bending element 31. In addition, as long as the bending element 31 can exert its bending function on the laser beam 51, the size and shape of the bending element 31 are not limited to the example shown in the figure, and any size and shape can be adopted.

[0162] like Figure 8-Figure 9 As shown, the bending element 31 has a film-like or plate-like substrate 36 and prism structures 37 , 38 formed on the surface of the substrate 36 .

[0163] The substrate 36 is formed of a transparent material that can transmit light. For example, the substrate 36 may be formed of a material having a light transmittance of 70% or more in the near infrared band. Similar to the substrate 41 of the diffuser 40, the substrate 36 of the bending element 31 may be formed of a known resin such as polymethyl methacrylate, polyethylene terephthalate, polycarbonate, cyclic olefin copolymer, cyclic olefin polymer, triacetyl cellulose, or other organic material. Alternatively, the substrate 36 may be formed of a known glass material such as quartz glass, borosilicate glass, white plate glass, or other inorganic material.

[0164] The prism structures 37 and 38 are concave-convex structures in which a plurality of fine prism shapes are repeatedly formed. The cross-sectional shape of each prism shape has, for example, a right triangle shape formed by combining an inclined surface having a predetermined inclination angle and a vertical surface. By arranging a plurality of prism shapes at a predetermined pitch on the surface of the bending element 31, the prism structures 37 and 38 having a sawtooth-like cross-sectional shape are formed.

[0165] In this embodiment, prism structures 37 and 38 are formed on both surfaces (front and back) of the base material 36 of the bending element 31. For example, a first prism structure 37 is formed on the surface of one side of the bending element 31, and a second prism structure 38 is formed on the surface of the other side of the bending element 31. The first prism structure 37 and the second prism structure 38 extend in directions intersecting with each other when viewed from above the XY plane.

[0166] Specifically, if Figure 8 and Fig. 9 As shown, the first prism structure 37 formed on the surface of the bending element 31 is composed of a plurality of prism shapes extending in the Y direction. The plurality of prism shapes of the first prism structure 37 are arranged at a relatively small pitch, and each of the prism shapes has a relatively steep inclination. On the other hand, the second prism structure 38 formed on the back of the bending element 31 is composed of a plurality of prism shapes extending in the X direction. The plurality of prism shapes of the second prism structure 38 are arranged at a relatively large pitch, and each of the prism shapes has a relatively gentle inclination. Therefore, the bending angle α of the light beam of the first prism structure 37 is XThe bending angle α of the light beam with the second prism structure 38 Y Different, α X >α Y .

[0167] Thus, the first prism structure 37 extends in the Y direction, and the second prism structure 38 extends in the X direction. That is, the first prism structure 37 and the second prism structure 38 extend in directions perpendicular to each other when viewed from above the XY plane. Fig. 9 As shown, the first prism structure 37 bends the laser beam 51 incident from the light source 20 to the bending element 31 in the X direction. On the other hand, the second prism structure 38 bends the laser beam 51 incident from the light source 20 to the bending element 31 in the Y direction. Therefore, using one bending element 31, the laser beam 51 can be compositely bent in both the X and Y directions.

[0168] Here, if Figure 7 As shown, the bending element 31 has a plurality of bending portions 35a to 35f having different bending functions. Laser beams 51a to 51f are incident on the bending portions 35a to 35f of the bending element 31 from the plurality of light emitting elements 21a to 21f of the light source 20, respectively. The bending portions 35a to 35f bend the laser beams 51a to 51f in different bending directions at different bending angles α.

[0169] For example, the bent portion 35a is bent at an angle α in the negative direction of the X direction. X a, and the bending angle α in the positive direction of the Y direction Y a bends the laser beam 51a (α X a=-30°、α Y a=+12.5°). The bent portion 35b is bent at an angle α in the positive direction of the Y direction. Y b bends the laser beam 51b, but does not bend it in the X direction (α X b=0°,α Y b=+12.5°). The bent portion 35c is bent at an angle α in the positive direction of the X direction. X c and the bending angle α in the positive direction of the Y direction Y c bends the laser beam 51c (α X c=+30°、α Y c=+12.5°). The bent portion 35d is bent at an angle α in the negative direction of the X direction. X d, and the bending angle α in the negative direction of the Y direction Y d bends the laser beam 51d (α X d=-30°、α Y d=-12.5°). The bent portion 35e is bent at an angle α in the negative direction of the Y direction. Ye bends the laser beam 51e and does not bend in the X direction (α X e=0°,α Y e = -12.5°). The bent portion 35f is bent at an angle α in the positive direction of the X direction. X f, and the bending angle α in the negative direction of the Y direction Y f bends the laser beam 51f (α X f=+30°、α Y f = -12.5°).

[0170] Thus, the bending element 31 of this embodiment is divided into six bending parts 35a to 35f. In addition, in order to make each bending part 35a to 35f play a different bending function, such as Fig. 9 As shown, on the front and back surfaces of the bending element 31, prism structures 37 and 38 are formed in different forms for each of the bending portions 35a to 35f.

[0171] Specifically, if Fig. 9 As shown, on the surface of the bending element 31, a curved portion 35a on one side is formed with a curved angle α in the negative direction of the X direction to allow the laser beam 51a to be bent. X On the other hand, on the surface of the curved portion 35c on the other side, a prism structure 37A is formed so that the laser beam 51c is bent at an angle α in the positive direction of the X direction. X The prism structure 37A and the prism structure 37B are both formed as the first prism structure 37 formed on the surface of the bending element 31, but the inclination directions of the prism shapes are opposite to each other between the prism structure 37A and the prism structure 37B. In addition, the prism structure 37A and 37B are not formed on the surface of the central curved portion 35b, and the surface is a flat surface. Therefore, the laser beam 51b is not bent in the X direction at the curved portion 35b, but is directly transmitted.

[0172] In addition, on the back side of the bending element 31, a curved portion 35a on one side is formed so that the laser beam 51a is bent at an angle α in the positive direction of the Y direction. Y On the other hand, a prism structure 38A is formed on the back of the curved portion 35d on the other side so that the laser beam 51d is bent at an angle α in the negative direction of the Y direction. Y d Curved prism structure 38B. These prism structure 38A and prism structure 38B both constitute the second prism structure 38 formed on the back surface of the bending element 31, but between the prism structure 38A and the prism structure 38B, the inclination directions of the prism shapes are opposite to each other.

[0173] As described above, in the bending element 31 of the present embodiment, prism structures 37A and 37B of different shapes are partially formed as the first prism structure 37 on the surface of the bending element 31. Furthermore, prism structures 38A and 38B of different shapes are partially formed as the second prism structure 38 on the back surface of the bending element 31. Moreover, the prism structures 37A and 37B extending in the Y direction and the prism structures 38A and 38B extending in the X direction extend in directions perpendicular to each other. Thus, in one bending element 31, six bending portions 35a to 35f having different bending functions can be realized.

[0174] [6. Configuration example of light irradiation device]

[0175] Next, refer to Figure 10 to Figure 15 , a configuration example of the light irradiation device 2 of this embodiment is described. Figure 10 to Figure 15 These are schematic diagrams showing configuration examples 1 to 6 of the light irradiation device 2 according to the present embodiment. In the following configuration examples 1 to 6, the parameters of the light distribution element 30 and the diffuser plate 40 are designed so as to satisfy the conditions of the above-mentioned equations (1) to (6).

[0176] (1) Structural Example 1

[0177] like Fig.10 As shown, the light irradiation device 2 of the structural example 1 of the present embodiment comprises: a light source 20 having a plurality of light emitting elements 21a to 21f; a bending element 31 as a light distribution element 30; and a diffusion plate 40. In the light irradiation device 2 of the structural example 1, in the irradiation path of the light beam from the light source 20 to the distance measurement target area 5, the light source 20, the bending element 31, and the diffusion plate 40 are arranged in this order.

[0178] Fig.10 The light distribution element 30 (bending element 31) of the configuration example 1 shown corresponds to the above Figures 5 to 9 The light distribution element 30 (bending element 31) shown in FIG. 1 has the above-mentioned prism structures 37 and 38. The bending element 31 has, for example, six bending portions 35a to 35f (see FIG. 35a ). Figure 7 ), through each bending portion 35a to 35f, with different bending angles αa (α X a、α Y a)~αf(α X f、α Y f), so that the laser beams 51a~51f are bent in different bending directions.

[0179] The bent light beams 52a to 52f bent by the bending element 31 are diffused by the diffuser 40 at a predetermined diffusion angle β to become diffused light beams 53a to 53f. The diffused light beams 53a to 53f are irradiated to the irradiation areas 7a to 7f of the distance measurement target area 5, respectively.

[0180] As described above, in the light irradiation device 2 of the structural example 1, the plurality of laser beams 51 from the light source 20 can be bent respectively by the bending element 31 as the light distribution element 30, and can be guided to each irradiation area 7. Thus, by switching on and off the plurality of light emitting elements 21, each irradiation area 7 can be locally irradiated with a light beam, and the above-mentioned light beam control operation can be appropriately performed.

[0181] Furthermore, according to Configuration Example 1, the light distribution element 30 is composed of a single thin curved element 31. Therefore, since the light distribution element 30 can be miniaturized, the light irradiation device 2 can also be miniaturized. Furthermore, by arranging the curved element 31 and the diffuser plate 40 in contact with or close to each other, the light irradiation device 2 can be further miniaturized.

[0182] (2) Structural Example 2

[0183] like Fig.11 As shown, the light irradiation device 2 of the structural example 2 of the present embodiment includes a light source 20, two bending elements 31A and 31B as a light distribution element 30, and a diffusion plate 40. In the light irradiation device 2 of the structural example 2, in the irradiation path of the light beam from the light source 20 to the distance measurement target area 5, the light source 20, the bending element 31A, the bending element 31B, and the diffusion plate 40 are arranged in this order.

[0184] Fig.11 The light distribution element 30 of the configuration example 2 shown in the figure replaces the above Fig.10 The bending element 31 of the structural example 1 shown in the figure is provided with two bending elements 31A and 31B (first and second bending elements). The bending elements 31A and 31B have the same shape as described above on their front and back surfaces. Figure 8-Figure 9 The example shown has the same prism structures 37 and 38. Thus, each bending element 31A and 31B has the function of bending the laser beam 51 from the light source 20 in the X and Y directions.

[0185] In the second structural example, the laser beam 51 from the light source 20 is first incident on the bending element 31A and is bent at a predetermined primary bending angle α. XA , α YA Next, the light that has been bent once by the bending element 31A enters the bending element 31B and is bent twice at a predetermined angle α. XB , α YB Secondary bending: The bent light beam 52 emitted from the bending element 31B is incident on the diffusion plate 40 and diffused, and then irradiates the irradiation area 7 of the distance measurement target area 5 .

[0186] Thus, the two bending elements 31A and 31B of the second structural example share the bending function of the laser beam 51 of the single bending element 31 of the first structural example. That is, the bending angle α in the X direction of the bending element 31A of the second structural example is XA and the bending angle α of the bending element 31B in the X direction XB The total angle of becomes the bending angle α in the X direction of the bending element 31 of the structural example 1 X (α X =α XA +α XB ). Similarly, the bending angle α of the bending element 31A in the Y direction YA The bending angle α with respect to the Y direction of the bending element 31B YB The total angle of becomes the bending angle α in the Y direction of the bending element 31 of the structural example 1 Y (α Y =α YA +α YB ).

[0187] As in the above-mentioned configuration example 2, by using a plurality of bending elements 31A and 31B as the light distribution element 30, even when the bending angle α required for the light distribution element 30 is large, it is possible to appropriately cope with it. Therefore, as the light distribution element 30, a large bending angle α can be obtained. X , α Y , so the viewing angle θ of the light irradiation device 2, It can be further expanded to irradiate the light beam to a wider range of the distance measurement target area 5.

[0188] (3) Structural Example 3

[0189] like Fig.12 As shown, the light irradiation device 2 of the structural example 3 of the present embodiment includes a light source 20, a plurality of reflectors 32 as light distribution elements 30, and a diffuser 40. In the light irradiation device 2 of the structural example 3, in the irradiation path of the light beam from the light source 20 to the distance measurement target area 5, the light source 20, the reflectors 32, and the diffuser 40 are arranged in this order.

[0190] Fig.12 The light distribution element 30 of the structural example 3 shown in the figure replaces the above Fig.10 The bending element 31 of the structural example 1 shown in the figure is provided with a plurality of reflectors 32. The reflectors 32 are optical elements having a mirror surface for reflecting light. The reflectors 32 are arranged to be inclined at a predetermined angle with respect to the optical axis direction (Z direction) of the laser beam 51 from the light source 20. The reflectors 32 reflect the laser beam 51 from the light source 20 so that the laser beam 51 is bent at a predetermined angle α. X , α Y The light beam 52 is bent and emitted in a predetermined bending direction.

[0191] By adjusting the inclination angle of the reflector 32 in the X direction, the bending angle α when the laser beam 51 is bent in the X direction can be changed. X Similarly, by adjusting the inclination angle of the reflector 32 in the Y direction, the bending angle α when the laser beam 51 is bent in the Y direction can be changed. Y In addition, a plurality of reflectors 32 having different inclination angles in the X and Y directions are provided corresponding to the plurality of light emitting elements 21a to 21f of the light source 20. Thus, by arranging and directing the plurality of reflectors 32 in different directions, the laser beams 51a to 51f from the light emitting elements 21a to 21f are bent at different bending angles α. X a~α X f、α Y a~α Y f is bent in the desired bending directions (X and Y directions). From this perspective, the plurality of reflectors 32 of the configuration example 3 are equivalent to the plurality of curved portions included in the light distribution element 30 .

[0192] By using a plurality of reflectors 32 as the light distribution element 30 as in the above-mentioned structural example 3, it is possible to bend a plurality of laser beams 51 from the light source 20, similarly to the bending element 31 in the above-mentioned structural example 1. In addition, in the bending element 31 in the structural example 1, ghosting is easily generated when the laser beam 51 is bent, but in the reflector 32 in the structural example 3, there is also an advantage that ghosting is not generated.

[0193] (4) Structural Example 4

[0194] like Fig.13 As shown, the light irradiation device 2 of the structural example 4 of the present embodiment includes a light source 20, a plurality of reflectors 32 and a bending element 31 as a light distribution element 30, and a diffusion plate 40. In the light irradiation device 2 of the structural example 4, in the irradiation path of the light beam from the light source 20 to the distance measurement target area 5, the light source 20, the reflector 32, the bending element 31, and the diffusion plate 40 are arranged in this order.

[0195] Fig.13 The light distribution element 30 of the configuration example 4 shown in the figure includes the above-mentioned plurality of reflectors 32 and the bending element 31. That is, Fig.13 The light distribution element 30 of the structural example 4 shown is a combination of Fig.12 The reflector 32 of the structural example 3 shown in FIG. Fig.10 An example of a bending element 31 of a prism structure 37 or 38 of Structural Example 1 is shown.

[0196] In the configuration example 4, the laser beam 51 from the light source 20 first enters the reflector 32 and is bent at a predetermined primary angle α. X1 , α Y1Next, the light beam that is bent once by the reflector 32 enters the bending element 31 and is bent twice at a predetermined angle α. X2 , α Y2 Secondary bending: The bent light beam 52 emitted from the bending element 31 is incident on the diffusion plate 40 and diffused, and then irradiates the irradiation area 7 of the distance measurement target area 5 .

[0197] Thus, the reflector 32 and the bending element 31 of the structural example 4 share the bending function of the laser beam 51 of the bending element 31 of the structural example 1. That is, the bending angle α of the reflector 32 in the structural example 4 in the X direction is X1 The bending angle α with respect to the X direction of the bending element 31 X2 The total angle of becomes the bending angle α in the X direction of the bending element 31 of the structural example 1 X (α X =α X1 +α X2 ). Similarly, the bending angle α of the reflector 32 in the Y direction is Y1 The bending angle α with respect to the Y direction of the bending element 31 Y2 The total angle of becomes the bending angle α in the Y direction of the bending element 31 of the structural example 1 Y (α Y =α Y1 +α Y2 ).

[0198] As in the above-mentioned configuration example 4, by using the reflector 32 and the bending element 31 in combination as the light distribution element 30, even when the bending angle α required by the light distribution element 30 is large, it can be appropriately handled. Therefore, as the light distribution element 30, a large bending angle α can be obtained. X , α Y , so the viewing angle θ of the light irradiation device 2, It can be further expanded, and the light beam can be irradiated to a wider range of the ranging target area 5.

[0199] (5) Structural Example 5

[0200] like Fig.14 As shown, the light irradiation device 2 of the structural example 5 of the present embodiment includes a light source 20, a bending element 31 as a light distribution element 30, a plurality of reflectors 32, and a diffuser 40. In the light irradiation device 2 of the structural example 5, in the irradiation path of the light beam from the light source 20 to the distance measurement target area 5, the light source 20, the bending element 31, the reflector 32, and the diffuser 40 are arranged in this order.

[0201] Fig.14 The light distribution element 30 of the configuration example 5 shown in the figure includes the above-mentioned bending element 31 and a plurality of reflectors 32. That is, Fig.14The light distribution element 30 of the structure example 5 shown is a combination of Fig.10 The bending elements 31 and 38 of the prism structures 37 and 38 of the structural example 1 shown in FIG. Fig.12 An example of the reflector 32 of the structural example 3 is shown.

[0202] In the configuration example 5, the laser beam 51 from the light source 20 is first incident on the bending element 31 and is bent at a predetermined primary bending angle α. X1 , α Y1 Next, the light beam that is bent once by the bending element 31 enters the reflector 32 and is bent twice at a predetermined angle α. X2 , α Y2 Secondary bending: The bent light beam 52 emitted from the reflector 32 is incident on the diffuser 40 and diffused, and then irradiates the irradiation area 7 of the distance measurement target area 5 .

[0203] Thus, the bending element 31 and the reflector 32 of the structural example 5 share the bending function of the laser beam 51 of the bending element 31 of the structural example 1. That is, the bending angle α of the bending element 31 in the structural example 5 in the X direction is X1 The bending angle α of the reflector 32 in the X direction X2 The total angle of becomes the bending angle α in the X direction of the bending element 31 of the structural example 1 X (α X =α X1 +α X2 ). Similarly, the bending angle α of the bending element 31 in the Y direction Y1 The bending angle α of the reflector 32 in the Y direction Y2 The total angle of becomes the bending angle α in the Y direction of the bending element 31 of the structural example 1 Y (α Y =α Y1 +α Y2 ).

[0204] As in the above-mentioned configuration example 5, by using the bending element 31 and the reflector 32 in combination as the light distribution element 30, even when the bending angle α required by the light distribution element 30 is large, it can be appropriately handled. Therefore, as the light distribution element 30, a large bending angle α can be obtained. X , α Y , so the viewing angle θ of the light irradiation device 2, It can be further expanded, and the light beam can be irradiated to a wider range of the ranging target area 5.

[0205] (6) Structural Example 6

[0206] like Fig.15As shown, the light irradiation device 2 of the structural example 6 of the present embodiment includes a light source 20, a plurality of prisms 33 as light distribution elements 30, and a diffuser 40. In the light irradiation device 2 of the structural example 6, in the irradiation path of the light beam from the light source 20 to the distance measurement target area 5, the light source 20, the prism 33, and the diffuser 40 are arranged in this order.

[0207] Fig.15 The light distribution element 30 of the structure example 6 shown in the figure replaces the above Fig.10 The bending element 31 of the structural example 1 shown in the figure is provided with a plurality of prisms 33. The prism 33 is an optical element having the function of refracting light. The prism 33 has an inclined surface inclined at a predetermined angle with respect to the optical axis direction (Z direction) of the laser beam 51. The laser beam 51 is refracted on the inclined surface of the prism 33. In this way, the prism 33 refracts the laser beam 51 from the light source 20 so as to bend the laser beam 51 at a predetermined bending angle α. X , α Y The light beam 52 is bent and emitted in a predetermined bending direction.

[0208] By adjusting the inclination angle of the inclined surface of the prism 33 in the X direction, the bending angle α when the laser beam 51 is bent in the X direction can be changed. X Similarly, by adjusting the inclination angle of the inclined surface of the prism 33 in the Y direction, the bending angle α when the laser beam 51 is bent in the Y direction can be changed. Y In addition, a plurality of prisms 33 having different inclination angles in the X and Y directions are provided corresponding to the plurality of light emitting elements 21a to 21f of the light source 20. Thus, by arranging and directing the plurality of prisms 33 in different directions, the laser beams 51a to 51f from the light emitting elements 21a to 21f are bent at different bending angles α. X a~α X f、α Y a~α Y f is bent in the desired bending directions (X and Y directions). From this perspective, the plurality of prisms 33 of Configuration Example 6 corresponds to the plurality of curved portions included in the light distribution element 30 .

[0209] As in the above-mentioned configuration example 6, by using a plurality of prisms 33 as the light distribution element 30, the plurality of laser beams 51 from the light source 20 can be bent in the same manner as the bending element 31 in the above-mentioned configuration example 1. Fig.15 The prism 33 shown is combined with the bending element 31 or the reflector 32 to form the light distribution element 30 .

[0210] Above, refer to Figure 10 to Figure 15 , structural examples 1 to 6 of the light irradiation device 2 of this embodiment are described. Figure 10 to Figure 15In the structural examples 1 to 6, the light distribution element 30 (bending element 31, reflector 32, prism 33, etc.) is arranged between the light source 20 and the diffuser 40. Thus, after the laser beam 51 is bent by the light distribution element 30, the bent beam 52 is diffused by the diffuser 40, so that the diffused beam 53 can be irradiated to the distance measurement target area 5, thereby improving the homogeneity of the diffused beam 53. However, the positional relationship between the light distribution element 30 and the diffuser 40 is not limited to Figure 10 to Figure 15 For example, a light distribution element 30 (bending element 31, reflector 32, prism 33, etc.) may be arranged between the diffuser 40 and the distance measurement target area 5. Thus, after the laser beam 51 is diffused by the diffuser 40, the diffused light beam is bent by the light distribution element 30, so the homogeneity of the light beam irradiated to each irradiation area 7 may be slightly reduced, but the light beam control operation for each irradiation area 7 can be performed without any problem.

[0211] [7. Conclusion]

[0212] The light irradiation device 2 having the diffuser plate 40 of the present embodiment has been described above. According to the present embodiment, in the light irradiation device 2 that diffuses the irradiation light beam using the diffuser plate 40, the distance measurement target area 5 is divided into a plurality of irradiation areas 7a to 7f, and the light distribution element 30 is arranged to be opposite to the diffuser plate 40, and the light distribution element 30 is used to bend the light beam (for example, a plurality of laser beams 51a to 51f) from the light source 20 toward the distance measurement target area 5 in a plurality of different bending directions. Thus, the irradiation areas 7a to 7f that are a part of the irradiation area 7a to 7f that have been reduced in the distance measurement target area 5 can be partially irradiated with the bent light beam.

[0213] Furthermore, the light source 20 may include a plurality of light emitting elements 21a to 21f arranged in one dimension or two dimensions, and the light irradiation device 2 may include a control unit 50 for controlling the light emission of the plurality of light emitting elements 21a to 21f. In addition, the light distribution element 30 may also be configured to bend the plurality of light beams 51a to 51f emitted from the plurality of light emitting elements 21a to 21f in mutually different bending directions. Furthermore, the diffuser plate 40 may also diffuse the light beams 52a to 52f bent by the light distribution element 30, respectively, and irradiate the diffused light beams 53a to 53f to the irradiation areas 7a to 7f of the distance measurement target area 5, respectively.

[0214] According to this configuration, by switching the light emitting elements 21a to 21f that emit light in a predetermined order by the control unit 50, the irradiation areas 7a to 7f where a part of the diffused light beams 53a to 53f are partially irradiated in the distance measurement target area 5 can be sequentially switched. Thus, the beam control operation of scanning the distance measurement target area 5 by switching the irradiation areas 7a to 7f can be performed (see Figure 6 ).

[0215] In this regard, in the light irradiation device 2' (see Figure 3 ), there is a problem that the light beam control operation cannot be performed in principle. In addition, in the light irradiation device 2' (refer to Figure 2 ), the light beam control action can be performed, but there is a problem of increased device size and cost.

[0216] In contrast, according to the present embodiment, in the light irradiation device 2 that uses the diffuser plate 40 to diffuse the light beam from the light source 20, the light beam control operation can be appropriately performed by adding the light distribution element 30 between the light source 20 and the distance measurement target area 5. Therefore, both the range of the entire irradiation area 7a to 7f (distance measurement target area 5) that can be irradiated with the diffused light beam 53 by the light irradiation device 2 and the irradiation distance of the diffused light beam 53 can be expanded.

[0217] Furthermore, according to the present embodiment, the lens unit 14 having a complex structure is not used, but the diffuser plate 40 having a simple structure is used to diffuse the light beam 51. Therefore, the problem of increased device size and cost as in the conventional light irradiation device 2' can be solved, and the size and cost of the light irradiation device 2 can be suppressed, which contributes to the miniaturization of the light irradiation device 2.

[0218] Furthermore, by diffusing the irradiation light beam by using the diffusion plate 40, it is possible to irradiate each irradiation area 7a to 7f with a uniform diffused light beam 53a to 53f. Therefore, even if a part of the plurality of light emitting elements 21 provided on the light source 20 as a surface light source is damaged or fails, it is possible to eliminate the problem of not irradiating the irradiation area 7e corresponding to the damaged part with a light beam and thus generating an unirradiated area (see Figure 4 ), and can stably measure the entire ranging target area 5.

[0219] Example

[0220] Next, a light irradiation device according to an embodiment of the present invention will be described. Note that the following embodiment is only an example for illustrating the effects and feasibility of the light irradiation device of the present invention, and the present invention is not limited to the following embodiment.

[0221] In this embodiment, the above Figures 5 to 10 The light irradiation device 2 of the structure shown in the figure is used to simulate the relative intensity distribution when the light irradiation device 2 is used to irradiate the distance measurement target area 5 with a diffuse light beam. As the light source 20, a surface light source is used in which six light emitting elements 21a to 21f composed of VCSELs are arranged in 2 rows and 3 columns on the light emitting surface 22. As the light distribution element 30, a surface light source is used in the above Figure 7 to Figure 9The bending element 31 is a rectangular flat plate with prism structures 37 and 38 formed on both sides. As the diffuser 40, a rectangular flat plate diffuser 40 with a microlens array 42 formed on one surface is used. The material of the bending element 31 and the diffuser 40 is an optical material with a refractive index of about 1.5. The bending angle α of the bending element 31 is set to X , α Y and the diffusion angle β of the diffuser plate 40 X , β Y , so that the field angle θ of the diffuse light beam 53 irradiated by the light irradiation device 2 in the X direction is about 90°, and the field angle in the Y direction is about About 50°.

[0222] Fig.16 This is a diagram showing the relative intensity distribution of the irradiation light beam when all the six light emitting elements 21a to 21f are simultaneously emitted (lit) in the light irradiation device 2 of the present embodiment. Fig.17 This is a photograph showing the relative intensity distribution of the irradiation beam.

[0223] like Fig.16 and Fig.17 As shown, the viewing angle θ in the X direction is within the range of about 90° (-45° to +45°) and the viewing angle in the Y direction is The diffuse light beam is irradiated to the entire irradiation area 7 of the approximately rectangular shape within a range of about 50° (-25° to +25°). At this time, it can be seen that the relative intensity distribution of the irradiation light beam in the entire irradiation area 7 is approximately uniform, and the intensity changes slowly. Therefore, it is confirmed that the light irradiation device 2 of this embodiment irradiates the irradiation area 7 approximately uniformly without generating an unirradiated area, and the entire area of ​​the irradiation area 7 in the ranging target area 5 can be appropriately measured.

[0224] Figure 18 to Figure 20 The photograph shows the relative intensity distribution of the irradiation light beam when the upper three light emitting elements 21a to 21c among the six light emitting elements 21a to 21f are sequentially emitted (lit) in the light irradiation device 2 of the present embodiment.

[0225] like Fig.18 As shown in FIG. 1 , when only one light emitting element 21a disposed at the upper left portion emits light toward the light emitting surface 22, only the substantially rectangular irradiation area 7a at the upper right portion of the distance measurement target area 5 is irradiated with the diffuse light beam 53a. Fig.19 As shown in FIG. 1 , when only one light emitting element 21b disposed at the upper center of the light emitting surface 22 emits light, only the substantially rectangular irradiation area 7b at the upper center of the distance measurement target area 5 is irradiated with the diffuse light beam 53b. Fig. 20As shown, when only one light emitting element 21 c arranged at the upper right portion is made to emit light toward the light emitting surface 22 , only the substantially rectangular irradiation area 7 c at the upper left portion of the distance measurement target area 5 is irradiated with the diffused light beam 53 c .

[0226] It can be seen from this that by sequentially switching on and off the light emitting elements 21a to 21c, the irradiation areas 7a to c that irradiate the diffuse light beam 53 in the distance measurement target area 5 can be sequentially switched to scan the distance measurement target area 5. Therefore, it is confirmed that the light irradiation device 2 of this embodiment can appropriately perform the beam control operation of partially irradiating each irradiation area 7 in the distance measurement target area 5 with the diffuse light beam 53.

[0227] The embodiments of the present invention are described above with reference to the accompanying drawings, but the present invention is certainly not limited to such embodiments. Those skilled in the art clearly know that various variations or modifications can be conceived within the scope described in the claims, and these variations certainly also belong to the technical scope of the present invention.

[0228] For example, in the above embodiment, an example in which the light source 20 is composed of a vertical cavity surface emitting laser (VCSEL) is described, but the present invention is not limited to this example. The light source can be composed of various surface emitting types of semiconductor lasers, such as a vertical external cavity surface emitting laser (VECSEL: Vertical External Cavity Surface Emitting Laser), an edge emitting laser (EEL: Edge Emitting Laser) or other surface emitting lasers (SEL: Surface Emitting Laser).

[0229] In addition, in the above-mentioned embodiment, an example in which the light source 20 is a surface light source having a plurality of light-emitting elements 21a to 21f is described, but the present invention is not limited to this example. As long as the light source has an area of ​​the light-emitting surface, it may be a single light source, and it may also be a point light source instead of a surface light source. In addition to general surface light sources that emit a plurality of parallel light beams or diffuse light beams from the light-emitting surface, the light source having the above-mentioned area also includes a point light source that emits a diffuse light beam. Even if the light source is a point light source, by configuring the point light source and the light distribution element to be separated, the diffuse light beam emitted from the point light source becomes a light beam having a specified area at the incident position relative to the light distribution element. Therefore, by using the light distribution element to bend the diffuse light beam from the point light source in different directions, it is possible to locally irradiate the light beam to each irradiation area that divides the ranging target area.

[0230] Description of Figure Numbers

[0231] 1Optical distance measuring device

[0232] 2. Light irradiation device

[0233] 3. Light detection device

[0234] 4 Controller

[0235] 5 Ranging target area

[0236] 6Distance measurement target

[0237] 7, 7a~7f Irradiation area

[0238] 20 Light Source

[0239] 21, 21a to 21f Light-emitting element

[0240] 30 light distribution components

[0241] 31 Bending elements

[0242] 32 Reflector

[0243] 33 Prism

[0244] 35, 35a~35f bending part

[0245] 36 Substrate

[0246] 37, 37A, 37B first prism structure

[0247] 38, 38A, 38B Second prism structure

[0248] 40 Diffuser Plate

[0249] 41 Substrate

[0250] 42 Microlens Array

[0251] 51, 51a~51f Laser beam

[0252] 52, 52a~52f Bending beam

[0253] 53, 53a~53f diffuse light beam.

Claims

1. A light irradiation device, which is arranged in an optical distance measuring device and irradiates a distance measuring target area with a light beam, characterized in that: have: Light source; and A light distribution element is provided to bend a light beam from the light source toward the distance measurement target area in a plurality of bending directions.

2. The light irradiation device according to claim 1, characterized in that It also includes a diffusion plate disposed between the light source and the distance measurement target area, The diffusion plate is arranged to face the light distribution element.

3. The light irradiation device according to claim 2, characterized in that The light source has a plurality of light emitting elements arranged in one dimension or two dimensions. The light distribution element bends the plurality of light beams emitted from the plurality of light emitting elements in different bending directions. The light irradiation device further includes a control unit that controls light emission of the plurality of light emitting elements.

4. The light irradiation device according to claim 3, characterized in that The plurality of light emitting elements respectively correspond to a plurality of irradiation areas that divide the distance measurement target area one-dimensionally or two-dimensionally, The plurality of light beams emitted from the plurality of light emitting elements are irradiated to the plurality of irradiation areas through the light distribution element and the diffusion plate, respectively. The control unit switches a light emitting element that emits light among the plurality of light emitting elements.

5. The light irradiation device according to claim 4, characterized in that The light distribution element has a plurality of curved portions corresponding to the plurality of irradiation areas respectively. The plurality of curved portions respectively bend the plurality of light beams emitted from the plurality of light emitting elements in different bending directions and guide the light beams to the plurality of irradiation areas.

6. The light irradiation device according to claim 5, characterized in that The light distribution element is arranged between the light source and the diffusion plate. The plurality of bent portions bend the plurality of light beams emitted from the plurality of light emitting elements in different bending directions and emit the light beams to the diffusion plate. The diffusion plate diffuses the plurality of bent light beams incident from the plurality of bent portions, respectively, and irradiates the plurality of diffused light beams traveling in directions different from each other to the plurality of irradiation areas, respectively.

7. The light irradiation device according to claim 2, characterized in that The light distribution element and the diffusion plate are arranged to be in contact with each other or to be joined via a joining member.

8. The light irradiation device according to claim 1, characterized in that The light distribution element includes a curved element having a prism structure.

9. The light irradiation device according to claim 8, characterized in that The prism structure is formed on surfaces of both sides of the bending element.

10. The light irradiation device according to claim 9, characterized in that A first prism structure is formed on a surface of one side of the bending element, and a second prism structure is formed on a surface of the other side of the bending element. The first prism structure and the second prism structure extend in directions intersecting with each other when viewed from above.

11. The light irradiation device according to claim 1, characterized in that: The light distribution element includes a reflector.

12. The light irradiation device according to claim 2, characterized in that: The diffusion plate has a microlens array.

13. An optical distance measuring device, characterized in that: have: The light irradiation device according to any one of claims 1 to 12; and A light detection device detects the light beam irradiated from the light irradiation device and reflected by the distance measurement target object.

14. A vehicle, characterized in that: A device comprising the optical distance measuring device according to claim 13.

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