Patent Application
20250199128
This application is based on and claims priority under 35 USC 119 from Japanese Patent Application No. 2023-210101 filed Dec. 13, 2023.
The present invention relates to a light emitting device and a distance measurement apparatus.
JP2020-191268A discloses a vehicular lamp including a plurality of light sources and a plurality of projection optical systems corresponding to the plurality of light sources, in which at least one light source among the plurality of light sources is disposed in a state of being shifted with respect to an optical axis of the projection optical system corresponding to the light source.
There is a distance measurement apparatus that measures a distance to a target object based on a result of irradiating the target object with light from a light emitting device and receiving light reflected by the target object.
In a case where a light emitting device that irradiates different irradiation regions with light beams using a plurality of light sources is used, a non-irradiation region, which is not irradiated with light, may be formed between the irradiation regions that are irradiated with light beams from the respective light sources. In the non-irradiation region, the target object is not irradiated with light, which makes it difficult for the distance measurement apparatus to measure the distance to the target object.
Aspects of non-limiting embodiments of the present disclosure relate to a light emitting device and a distance measurement apparatus that prevent a non-irradiation region, which is not irradiated with light, from being formed between different irradiation regions in a case where the irradiation regions are irradiated with light beams using a plurality of light sources, as compared with a case where center lines of the light beams emitted from the plurality of light sources to the irradiation regions do not intersect each other.
Aspects of certain non-limiting embodiments of the present disclosure overcome the above disadvantages and/or other disadvantages not described above. However, aspects of the non-limiting embodiments are not required to overcome the disadvantages described above, and aspects of the non-limiting embodiments of the present disclosure may not overcome any of the disadvantages described above.
According to an aspect of the present disclosure, there is provided a light emitting device including a light emitting unit that emits light, an optical system that expands an irradiation range of the light emitted from the light emitting unit as a distance from the light emitting unit increases, and a plurality of light sources each having the light emitting unit and the optical system and irradiating different irradiation regions with light beams, in which center lines of the light beams emitted from the light sources to the irradiation regions intersect each other.
Exemplary embodiment(s) of the present invention will be described in detail based on the following figures, wherein:
Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings.
The technical scope of the present invention is not limited to the scope to be described below as an exemplary embodiment. It is clear from the description of the claims that a combination of a plurality of examples and various modifications or improvements to the exemplary embodiment described above are also included in the technical scope of the present invention.
The distance measurement apparatus 1 measures a distance to a target object based on a time from a timing at which light is emitted from a light emitting unit 4 to a timing at which the light reflected by the target object is received by a light receiving unit 5. That is, the distance measurement apparatus 1 is an apparatus that performs distance measurement based on a ToF method. The ToF method includes an indirect ToF (iToF) method in which a time is measured from a difference between a phase of emitted light and a phase of received light, and a direct ToF (dToF) method in which a time from emission to reception of light is directly measured. In the present exemplary embodiment, description will be made assuming that the distance measurement apparatus 1 performs distance measurement based on the indirect ToF method.
As shown in
The optical device 3 includes the light emitting unit 4 that emits light toward a predetermined range, the light receiving unit 5 that receives light reflected by the target object existing in an irradiation range of the light emitted from the light emitting unit 4, a light emission drive unit 6 that drives the light emitting unit 4, and a light reception drive unit 7 that drives the light receiving unit 5. The light emitting unit 4 is an example of a light emitting device. The light emission drive unit 6 is an example of a drive unit.
The control unit 8 controls the operations of the light emitting unit 4 and the light receiving unit 5 of the optical device 3.
In addition, the control unit 8 acquires a result of the light reception by the light receiving unit 5, and measures a distance from the distance measurement apparatus 1 to the target object by the ToF method based on a result of the light reception.
The control unit 8 is an example of a distance measurement unit.
The control unit 8 is configured of a central processing unit (CPU) 81, a read only memory (ROM) 82, and a random access memory (RAM) 83.
The CPU 81 is an example of a processor, and implements each function, which will be described below, by loading various programs stored in the ROM 82 or the like into the RAM 83 and executing the programs. The RAM 83 is a memory used as a work memory or the like of the CPU 81. The ROM 82 is a memory that stores various programs and the like executed by the CPU 81.
Here, the program executed by the CPU 81 may be provided in a state of being stored in a computer-readable recording medium such as a magnetic recording medium (a magnetic tape, a magnetic disk, or the like), an optical recording medium (an optical disk or the like), a magneto-optical recording medium, or a semiconductor memory. In addition, the program executed by the CPU 81 may be provided by using a communication section such as the Internet.
In the embodiments above, the term “processor” refers to hardware in a broad sense. Examples of the processor include general processors (e.g., CPU: Central Processing Unit) and dedicated processors (e.g., GPU: Graphics Processing Unit, ASIC: Application Specific Integrated Circuit, FPGA: Field Programmable Gate Array, and programmable logic device). In the embodiments above, the term “processor” is broad enough to encompass one processor or plural processors in collaboration which are located physically apart from each other but may work cooperatively. The order of operations of the processor is not limited to one described in the embodiments above, and may be changed.
The light emitting unit 4 has a plurality of (two in this example) light sources 4A and 4B that irradiate different irradiation regions 100A and 100B with light beams. In other words, the light emitting unit 4 has the light source 4A that irradiates the irradiation region 100A with light and the light source 4B that irradiates the irradiation region 100B different from the irradiation region 100A with light. Here, the irradiation region 100A is a region through which the light emitted from the light source 4A passes. Similarly, the irradiation region 100B is a region through which the light emitted from the light source 4B passes. The fact that the irradiation region 100A and the irradiation region 100B are different means that the irradiation region 100A and the irradiation region 100B do not coincide with each other, and the irradiation region 100A and the irradiation region 100B may have an overlapping portion.
In addition, the light emitting unit 4 includes a housing 44 (see
As shown in
Each of the light sources 4A and 4B has a light emitting chip 41 which is an example of a light emitting unit that emits light in the +z direction. In addition, each of the light sources 4A and 4B has a lens 42 which is an example of an optical system that expands an irradiation range of the light emitted from the light emitting chip 41 as a distance from the light emitting chip 41 increases in the +z direction. In addition, each of the light sources 4A and 4B has a support member 43 that supports the light emitting chip 41 and the lens 42 such that the light emitting chip 41 is disposed at a predetermined relative position with respect to the lens 42.
The light source 4A and the light source 4B have the same configuration except for a relative position of the light emitting chip 41 with respect to the lens 42.
The light emitting chip 41 has a light emitting surface on which a plurality of vertical cavity surface emitting lasers (VCSELs) (referred to as VCSELs hereinafter, and shown by reference numeral 45 in
The light emitting chips 41 are disposed such that the light emitting surfaces 411 and 412 are located along an xy plane. In this example, as shown in
The light emitting chips 41 emit light beams in the +z direction from the light emitting surfaces 411 and 412 by the light emission of the VCSEL.
Here, the respective light emitting chips 41 of the light sources 4A and 4B of the light emitting unit 4 according to the present exemplary embodiment are independently driven by the light emission drive unit 6 (see
Here, the phrase “independently driven” refers to a state in which light is emitted by driving each of the light sources 4A and 4B. The light emission drive unit 6 drives each light emitting chip 41 in response to a control signal from the control unit 8 (see
The lens 42 is provided on the +z direction side with respect to the light emitting chip 41. It should be noted that the lens 42 is provided on a downstream side of the light emitting chip 41 in a direction in which the light emitting chip 41 emits light. In addition, the lenses 42 are provided to face the light emitting surfaces 411 and 412 of the light emitting chips 41. As a result, the light beams emitted from the light emitting surfaces 411 and 412 of the light emitting chips 41 in the +z direction are incident into the lenses 42.
In addition, the lens 42 is disposed such that an optical axis 420 extends in the z direction. The lens 42 refracts the light emitted from the light emitting chip 41 in a direction intersecting the z direction, thereby expanding the irradiation range of the light in the +z direction.
In
In addition, in the following description, four regions in which the lens 42 is divided by the first straight line Lx and the second straight line Ly will be referred to as a first region 421, a second region 422, a third region 423, and a fourth region 424, respectively. The first region 421 is a region of the lens 42 on the +y direction side with respect to the first straight line Lx and on the −x direction side with respect to the second straight line Ly. The second region 422 is a region of the lens 42 on the +y direction side with respect to the first straight line Lx and on the +x direction side with respect to the second straight line Ly. The third region 423 is a region of the lens 42 on the −y direction side with respect to the first straight line Lx and on the −x direction side with respect to the second straight line Ly. The fourth region 424 is a region of the lens 42 on the −y direction side with respect to the first straight line Lx and on the +x direction side with respect to the second straight line Ly.
The lens 42 has a circular shape with the optical axis 420 as the center in a case of being viewed along the z direction. The lens 42 has an axisymmetric optical property with the optical axis 420 as the center. More specifically, the lens 42 refracts the light incident along the +z direction in a direction approaching the optical axis 420. That is, the lens 42 refracts the light incident into the first region 421 in the +x direction and the −y direction. In addition, the lens 42 refracts the light incident into the second region 422 in the −x direction and the −y direction. In addition, the lens 42 refracts the light incident into the third region 423 in the +x direction and the +y direction. In addition, the lens 42 refracts the light incident into the fourth region 424 in the −x direction and the +y direction. Further, the lens 42 has an optical property of refracting incident light more larger as the incident light is directed from the optical axis 420 toward a circumference along a radial direction. The lens 42 does not refract light incident into the optical axis 420.
As described above, the light sources 4A and 4B have different positions of the light emitting chip 41 with respect to the lens 42.
As shown in
Specifically, in the light source 4A, the light emitting chip 41 and the lens 42 are disposed such that a center 411C of the light emitting surface 411 is located to be shifted in the +y direction with respect to the optical axis 420 of the lens 42. In addition, in the light source 4A, the light emitting chip 41 and the lens 42 are disposed such that the center 411C of the light emitting surface 411 is located on the second straight line Ly of the lens 42. Further, in the light source 4A, the light emitting chip 41 and the lens 42 are disposed such that the long side 411x located on the −y direction side of the light emitting surface 411 overlaps the first straight line Lx of the lens 42.
In addition, in the light source 4B, the light emitting chip 41 and the lens 42 are disposed such that a position of the light emitting surface 412 with respect to the lens 42 is symmetrical to a position of the light emitting surface 411 with respect to the lens 42 in the light source 4A, with the first straight line Lx of the lens 42 as a symmetry axis.
That is, as shown in
Specifically, in the light source 4B, the light emitting chip 41 and the lens 42 are disposed such that a center 412C of the light emitting surface 412 is located to be shifted in the −y direction with respect to the optical axis 420 of the lens 42. In addition, in the light source 4B, the light emitting chip 41 and the lens 42 are disposed such that the center 412C of the light emitting surface 412 is located on the second straight line Ly of the lens 42. Further, in the light source 4B, the light emitting chip 41 and the lens 42 are disposed such that the long side 412x located on the ty direction side of the light emitting surface 412 overlaps the first straight line Lx of the lens 42.
In the light emitting unit 4 according to the present exemplary embodiment, the light emitting surface 411 of the light emitting chip 41 in the light source 4A and the light emitting surface 412 of the light emitting chip 41 in the light source 4B overlap the first straight lines Lx of each lens 42. As a result, there is no gap between the relative positions of the light emitting surface 411 and the light emitting surface 412 with respect to the lens 42.
In the light emitting unit 4 according to the present exemplary embodiment, the relative positions of the light emitting surface 411 and the light emitting surface 412 with respect to the lens 42 overlap only on the first straight line Lx of the lenses 42, but the present invention is not limited to this. For example, in the present exemplary embodiment, the light emitting surface 411 may be disposed by being shifted on the −y direction side with respect to
Irradiation Region with Light from Light Emitting Unit 4
Subsequently, the relationship between the irradiation region 100A that is irradiated with the light emitted from the light source 4A and the irradiation region 100B that is irradiated with the light emitted from the light source 4B will be described with reference to
In the light source 4A, the light emitted from the light emitting surface 411 of the light emitting chip 41 is incident onto the first straight line Lx of the lens 42 and into the first region 421 and the second region 422 on the ty direction side with respect to the first straight line Lx. In this example, the light emitted from the light emitting surface 411 is incident into the lens 42 along the +z direction.
Then, the light incident into the lens 42 from the light emitting surface 411 is refracted in the direction approaching the optical axis 420 by the optical property of the lens 42. Specifically, the light incident into the first region 421 of the lens 42 from the light emitting surface 411 is refracted in the +x direction and the −y direction. In addition, the light incident into the second region 422 of the lens 42 from the light emitting surface 411 is refracted in the −x direction and the −y direction. The light refracted by the lens 42 is emitted from the light source 4A.
In the light source 4B, the light emitted from the light emitting surface 412 of the light emitting chip 41 is incident onto the first straight line Lx of the lens 42 and into the third region 423 and the fourth region 424 on the −y direction side with respect to the first straight line Lx. In this example, the light emitted from the light emitting surface 412 is incident into the lens 42 in the +z direction.
Then, the light incident into the lens 42 from the light emitting surface 412 is refracted in the direction approaching the optical axis 420 by the optical property of the lens 42. Specifically, the light incident into the third region 423 of the lens 42 from the light emitting surface 412 is refracted in the +x direction and the +y direction. In addition, the light incident into the fourth region 424 of the lens 42 from the light emitting surface 412 is refracted in the −x direction and the +y direction. The light refracted by the lens 42 is emitted from the light source 4B.
As described above, the lens 42 has the optical property of refracting incident light more larger as the incident light is directed from the optical axis 420 toward a circumference along a radial direction.
As a result, the irradiation region 100A that is irradiated with the light emitted from the light source 4A is expanded in the ±x direction and the −y direction as it goes in the +z direction. A center line 101A of the irradiation region 100A is inclined toward the −y direction as it goes in the +z direction.
In addition, the irradiation region 100B that is irradiated with the light emitted from the light source 4B is expanded in the +x direction and the +y direction as it goes in the +z direction. A center line 101B of the irradiation region 100B is inclined toward the +y direction as it goes in the +z direction.
In the light emitting unit 4 according to the present exemplary embodiment, as shown in
Here, in the present exemplary embodiment, the intersection of the center line 101A of the irradiation region 100A and the center line 101B of the irradiation region 100B means that the irradiation region 100A and the irradiation region 100B have a point at which the center line 101A and the center line 101B intersect each other in a case where the irradiation region 100A and the irradiation region 100B are viewed along one direction (the x direction in this example) intersecting the z direction. Hereinafter, the point at which the center line 101A and the center line 101B intersect will be referred to as an intersection portion 102.
In addition, the center line 101A of the irradiation region 100A is a line connecting centers of irradiation surfaces which are irradiated with the light beams from the light source 4A among irradiation surfaces which are irradiated with the light beams emitted from the light emitting unit 4. Similarly, the center line 101B of the irradiation region 100B is a line connecting centers of irradiation surfaces which are irradiated with the light beams from the light source 4B among irradiation surfaces which are irradiated with the light beams emitted from the light emitting unit 4.
In the present exemplary embodiment, the irradiation region 100A and the irradiation region 100B are arranged in the −y direction on the −z direction side with respect to the intersection portion 102. In addition, on the +z direction side with respect to the intersection portion 102, the irradiation region 100A and the irradiation region 100B are arranged in the ty direction. It should be noted that the arrangement of the irradiation region 100A and the irradiation region 100B is reversed between the −z direction side and the +z direction side with respect to the intersection portion 102. It should be further noted that, on the +z direction side with respect to the intersection portion 102, the arrangement of the irradiation region 100A and the irradiation region 100B is reversed from the arrangement of the light source 4A and the light source 4B.
In the light emitting unit 4 according to the present exemplary embodiment, the intersection portion 102 is located inside the housing 44. The reason for this will be described in detail below.
In addition, in the present exemplary embodiment, a non-irradiation region 100X, which is not irradiated with the light beams emitted from the light source 4A and the light source 4B, is formed between the irradiation region 100A and the irradiation region 100B on the −z direction side with respect to the intersection portion 102. In this example, as shown in
In a case where different irradiation regions are irradiated with light beams using a plurality of light sources as in the light emitting unit 4 according to the present exemplary embodiment, a non-irradiation region, which is not irradiated with light, may be formed between the irradiation regions that are irradiated with light beams from the respective light sources. In addition, the non-irradiation region may be formed in a wide range in the +z direction from the light sources, depending on a positional relationship between the plurality of light sources, a direction of the light emitted from each light source, and the like. For example, in a case where the different irradiation regions are irradiated with light beams using the plurality of light sources such that the center lines of the irradiation regions do not intersect each other, the non-irradiation region is likely to be formed in a wide range in the +z direction from the light sources. In the non-irradiation region, the target object is not irradiated with the light from the light source, so that it is not possible to measure the distance to the target object based on the light reflected by the target object.
On the other hand, in the light emitting unit 4 according to the present exemplary embodiment, the light sources 4A and 4B emit light beams such that the center line 101A of the irradiation region 100A and the center line 101B of the irradiation region 100B intersect each other, so that the non-irradiation region 100X is not formed on the +z direction side with respect to the intersection portion 102. As a result, in the light emitting unit 4 according to the present exemplary embodiment, the range in which the non-irradiation region 100X is formed may be narrowed as compared with a case where the light beams are emitted using the plurality of light sources such that the center lines of the irradiation regions do not intersect each other.
In addition, in the light emitting unit 4 according to the present exemplary embodiment, the non-irradiation region 100X is located inside the housing 44. As a result, the target object, which is a target of the distance measurement, is prevented from entering the non-irradiation region 100X in which the distance to the target object cannot be measured.
The irradiation surface is a surface on which light from the light emitting unit 4 orthogonal to the z direction is emitted at a certain distance in the z direction of the irradiation regions 100A and 100B that are irradiated with the light beams emitted from the light sources 4A and 4B of the light emitting unit 4.
In the light sources 4A and 4B (see
The irradiation surface 210 includes an irradiation surface 211 that is irradiated with the light from the light source 4A and an irradiation surface 212 that is irradiated with the light from the light source 4B. In the irradiation surface 210, the irradiation surface 211 and the irradiation surface 212 are arranged in the y direction. In this example, the irradiation surface 211 is located on the −y direction side with respect to the irradiation surface 212. That is, the arrangement of the light sources 4A and 4B in the light emitting unit 4 and the arrangement of the irradiation surfaces 211 and 212 on the irradiation surface 210 are reversed.
In addition, on the irradiation surface 210, an overlapping region 213 in which partial regions of the irradiation surface 211 and the irradiation surface 212 in the y direction overlap each other is formed. It should be noted that, on the irradiation surface 210, an overlapping region 213 in which a partial region on the +y direction side in the irradiation surface 211 and a partial region on the −y direction side in the irradiation surface 212 overlap each other is formed.
Similarly, the irradiation surface 220 includes an irradiation surface 221 that is irradiated with the light from the light source 4A and an irradiation surface 222 that is irradiated with the light from the light source 4B. In the irradiation surface 220, the irradiation surface 221 and the irradiation surface 222 are arranged in the y direction. In this example, the irradiation surface 221 is located on the −y direction side with respect to the irradiation surface 222. That is, the arrangement of the light sources 4A and 4B in the light emitting unit 4 and the arrangement of the irradiation surfaces 221 and 222 on the irradiation surface 220 are reversed.
In addition, on the irradiation surface 220, an overlapping region 223 in which partial regions of the irradiation surface 221 and the irradiation surface 222 in the y direction overlap each other is formed. It should be noted that, on the irradiation surface 220, an overlapping region 223 in which a partial region on the +y direction side in the irradiation surface 221 and a partial region on the −y direction side in the irradiation surface 222 overlap each other is formed.
Similarly, the irradiation surface 230 includes an irradiation surface 231 that is irradiated with the light from the light source 4A and an irradiation surface 232 that is irradiated with the light from the light source 4B. On the irradiation surface 230, the irradiation surface 231 and the irradiation surface 232 are arranged in the y direction. In this example, the irradiation surface 231 is located on the −y direction side with respect to the irradiation surface 232. That is, the arrangement of the light sources 4A and 4B in the light emitting unit 4 and the arrangement of the irradiation surfaces 231 and 232 on the irradiation surface 230 are reversed.
In addition, on the irradiation surface 230, an overlapping region 233 in which partial regions of the irradiation surface 231 and the irradiation surface 232 in the y direction overlap each other is formed. It should be noted that, on the irradiation surface 230, an overlapping region 233 in which a partial region on the +y direction side in the irradiation surface 231 and a partial region on the −y direction side in the irradiation surface 232 overlap each other is formed.
In the irradiation surfaces 210, 220, and 230, the overlap between the irradiation surfaces 211, 221, and 231 that are irradiated with the light from the light source A and the irradiation surfaces 212, 222, and 232 that are irradiated with the light from the light source 4B is reduced as the distance from the light sources 4A and 4B increases in the +z direction. In addition, although not shown, the irradiation surface that is irradiated with the light from the light source 4A and the irradiation surface that is irradiated with the light from the light source 4B are not formed with the overlapping region at a certain distance away from the light sources 4A and 4B in the +z direction.
As a result, a ratio of the area of the overlapping region 213, 223, and 233 to the area of the irradiation surfaces 210, 220, and 230 is reduced as the distance from the light sources 4A and 4B increases. Specifically, the ratio of the area of the overlapping region 223 to the area of the irradiation surface 220 is smaller than the ratio of the area of the overlapping region 213 to the area of the irradiation surface 210. In addition, the ratio of the area of the overlapping region 233 to the area of the irradiation surface 230 is smaller than the ratio of the area of the overlapping region 223 to the area of the irradiation surface 220.
In addition, in the irradiation surface 210, the area of the overlapping region 213 is larger than a sum of the area of the irradiation surface 211 excluding the overlapping region 213 and the area of the irradiation surface 212 excluding the overlapping region 213.
On the other hand, in the irradiation surface 220, the area of the overlapping region 223 is smaller than a sum of the area of the irradiation surface 221 excluding the overlapping region 223 and the area of the irradiation surface 222 excluding the overlapping region 223.
Similarly, in the irradiation surface 230, the area of the overlapping region 233 is smaller than a sum of the area of the irradiation surface 231 excluding the overlapping region 233 and the area of the irradiation surface 232 excluding the overlapping region 233.
As described above, on the irradiation surface located on the +z direction side with respect to the intersection portion 102, the closer to the intersection portion 102, the higher the ratio of the area of the overlapping region to the area of the irradiation surface. In a case where the light source 4A and the light source 4B are simultaneously turned on, in the overlapping region, the light from the light source 4A and the light from the light source 4B are emitted, so that the amount of emitted light is larger than that in a region other than the overlapping region.
In a case where the target object enters the overlapping region which is close to the intersection portion 102, the amount of light emitted to the target object may be excessive. In this case, the amount of light received by a light receiving element, which will be described below, of the light receiving unit 5 that receives the light reflected by the target object may be excessive, resulting in signal saturation. In this case, it becomes difficult to measure the distance to the target object. In addition, in a case where the target object is a human, an eye safety problem may occur because of an excessive amount of irradiated light.
On the other hand, in the light emitting unit 4 according to the present exemplary embodiment, the intersection portion 102 is located inside the housing 44.
As a result, the target object is prevented from entering the overlapping region which is close to the intersection portion 102. In the examples shown in
The light receiving unit 5 includes a light receiving surface that extends in the x direction and the y direction and in which a plurality of light receiving elements are arranged. Then, the light receiving unit 5 receives the light emitted from the light emitting unit 4 and reflected by the target object, by each light receiving element.
The light receiving surface is divided into a plurality of light receiving sections corresponding to the plurality of light sources 4A and 4B of the light emitting unit 4. In the light receiving unit 5 according to the present exemplary embodiment, the light receiving surface is divided into two light receiving sections in the y direction. Each light receiving section has a plurality of light receiving elements that are regularly arranged. Each light receiving element receives the light emitted from the light sources 4A and 4B of the light emitting unit 4 and reflected by the target object, and outputs an electrical signal in response to the received light. Examples of the light receiving element include a photodiode or a phototransistor.
Each light receiving element of the light receiving unit 5 according to the present exemplary embodiment receives the light reflected by the target object at a position farther from the light emitting unit 4 than the intersection portion 102 where the center line 101A of the irradiation region 100A and the center line 101B of the irradiation region 100B intersect each other.
Each light receiving section is independently driven by the light reception drive unit 7 (see
In addition, in a case where the light receiving element included in each light receiving section receives light, the light receiving element outputs an electrical signal corresponding to the received light to the control unit 8.
In the light emitting unit 4, the light emitting surface 411 of the light emitting chip 41 included in the light source 4A and the light emitting surface 412 of the light emitting chip 41 included in the light source 4B may be divided into a plurality of light emitting sections. Hereinafter, as Exemplary Embodiment 2 of the present invention, an aspect in which the light emitting surfaces 411 and 412 are divided into a plurality of light emitting sections will be described. The same reference numerals are used for the same configurations as in Exemplary Embodiment 1 described above, and the detailed description thereof will be omitted here.
The light emitting surface 411 of the light source 4A in
In the present specification, the term “to” indicates a plurality of components distinguished individually by numbers, and means that components before and after “to” and components having numbers between the components are included. For example, the light emitting sections A1 to A16 include 16 light emitting sections 411A from the light emitting section A1 to the light emitting section A16 in numerical order.
The light emitting surface 412 of the light source 4B in
Each light emitting section 411A of the light source 4A and each light emitting section 412B of the light source 4B are independently driven by the light emission drive unit 6 (see
The light emission drive unit 6 drives each light emitting section 411A of the light source 4A and each light emitting section 412B of the light source 4B in response to a control signal from the control unit 8 (see
The irradiation surface 310 includes an irradiation surface 311 that is irradiated with the light from the light source 4A, and an irradiation surface 312 that is irradiated with the light from the light source 4B. On the irradiation surface 310, the irradiation surface 311 and the irradiation surface 312 are arranged in the y direction. In addition, on the irradiation surface 310, an overlapping region 313 in which a partial region on the ty direction side in the irradiation surface 311 and a partial region on the −y direction side in the irradiation surface 312 overlap each other is formed.
The irradiation surface 311 is divided into a plurality of irradiation sections 311C corresponding to the light emitting sections 411A on the light emitting surface 411. In the example of
The light emitted from each of the light emitting sections A1 to A16 of the light emitting surface 411 is refracted by the lens 42 (see
Similarly, the irradiation surface 312 is divided into a plurality of irradiation sections 312D corresponding to the light emitting sections 412B on the light emitting surface 412. In the example of
The light emitted from each of the light emitting sections B1 to B16 of the light emitting surface 412 is refracted by the lens 42 and is emitted to the irradiation surface 312. As a result, on the irradiation surface 312, the irradiation sections D1 to D16 are arranged in the order from the lower right side (the end in the +x direction and the −y direction) in
In the irradiation surface 310, the irradiation section C13 of the irradiation surface 311 and the irradiation section D1 of the irradiation surface 312 are adjacent to each other in the y direction. In addition, the irradiation section C14 of the irradiation surface 311 and the irradiation section D2 of the irradiation surface 312 are adjacent to each other in the y direction. In addition, the irradiation section C15 of the irradiation surface 311 and the irradiation section D3 of the irradiation surface 312 are adjacent to each other in the y direction. In addition, the irradiation section C16 of the irradiation surface 311 and the irradiation section D4 of the irradiation surface 312 are adjacent to each other in the y direction.
As described above, the overlapping region 313 is formed on the irradiation surface 310.
The overlapping region 313 includes an overlapping portion E1 in which a partial region on the +y direction side of the irradiation section C13 of the irradiation surface 311 and a partial region on the −y direction side of the irradiation section D1 of the irradiation surface 312 overlap each other. In addition, the overlapping region 313 includes an overlapping portion E2 in which a partial region on the ty direction side of the irradiation section C14 of the irradiation surface 311 and a partial region on the −y direction side of the irradiation section D2 of the irradiation surface 312 overlap each other. In addition, the overlapping region 313 includes an overlapping portion E3 in which a partial region on the ty direction side of the irradiation section C15 of the irradiation surface 311 and a partial region on the −y direction side of the irradiation section D3 of the irradiation surface 312 overlap each other. In addition, the overlapping region 313 includes an overlapping portion E4 in which a partial region on the +y direction side of the irradiation section C16 of the irradiation surface 311 and a partial region on the −y direction side of the irradiation section D4 of the irradiation surface 312 overlap each other. The overlapping portions E1 to E4 are arranged in the −x direction.
The light receiving unit 5 includes a light receiving surface that extends in the x direction and the y direction and in which a plurality of light receiving elements are arranged, as in Exemplary Embodiment 1 described above.
The light receiving surface is divided into a plurality of light receiving sections corresponding to the irradiation sections C1 to C16 of the irradiation surface 311 that is irradiated with the light beams from the light emitting sections A1 to A16 of the light source 4A and the irradiation sections D1 to D16 of the irradiation surface 312 that is irradiated with the light beams from the light emitting sections B1 to B16 of the light source 4B. That is, the light receiving surface includes 16 light receiving sections arranged in four rows in the x direction and four rows in the y direction corresponding to the irradiation sections C1 to C16, and 16 light receiving sections arranged in four rows in the x direction and four rows in the y direction corresponding to the irradiation sections D1 to D16.
Each light receiving section receives light emitted from the light sources 4A and 4B of the light emitting unit 4 and reflected by the target object existing in the corresponding irradiation section of the irradiation surface 311 and the irradiation surface 312. Each light receiving section of the light receiving unit 5 is independently driven by the light reception drive unit 7 (see
Subsequently, an operation of the light emitting unit 4 driven by the light emission drive unit 6 under the control of the control unit 8 will be described.
In the light emitting unit 4, in a case where the light emitting section of the light source 4A and the light emitting section of the light source 4B, which irradiate the overlapping region 313 with light beams, are simultaneously turned on, the overlapping region 313 is irradiated with the light from the light emitting section of the light source 4A and the light from the light emitting section of the light source 4B. In this case, the amount of light emitted to the overlapping region 313 is larger than that in a region other than the overlapping region of the irradiation surface 310. As a result, the amount of light emitted to the irradiation surface 310 is non-uniform in the overlapping region 313 and the region other than the overlapping region 313.
On the other hand, the control unit 8 of the present exemplary embodiment does not simultaneously turn on the light emitting section of the light source 4A and the light emitting section of the light source 4B, which irradiate the irradiation sections that form the overlapping region 313 with light beams. In other words, the control unit 8 does not simultaneously turn on in the light emitting section of the light source 4A and the light emitting section of the light source 4B, which irradiate the irradiation sections adjacent to each other in the irradiation surface 311 and the irradiation surface 312 with light beams.
More specifically, the control unit 8 does not simultaneously turn on the light emitting section A13 of the light source 4A that irradiates the irradiation section C13 that forms the overlapping portion E1 of the overlapping region 313 with light and the light emitting section B1 of the light source 4B that irradiates the irradiation section D1 that forms the overlapping portion E1 with light.
In addition, the control unit 8 does not simultaneously turn on the light emitting section A14 of the light source 4A that irradiates the irradiation section C14 that forms the overlapping portion E2 of the overlapping region 313 with light and the light emitting section B2 of the light source 4B that irradiates the irradiation section D2 that forms the overlapping portion E2 with light.
In addition, the control unit 8 does not simultaneously turn on the light emitting section A15 of the light source 4A that irradiates the irradiation section C15 that forms the overlapping portion E3 of the overlapping region 313 with light and the light emitting section B3 of the light source 4B that irradiates the irradiation section D3 that forms the overlapping portion E3 with light.
In addition, the control unit 8 does not simultaneously turn on the light emitting section A16 of the light source 4A that irradiates the irradiation section C16 that forms the overlapping portion E4 of the overlapping region 313 with light and the light emitting section B4 of the light source 4B that irradiates the irradiation section D4 that forms the overlapping portion E4 with light.
The control unit 8 according to the present exemplary embodiment turns on all the light emitting sections A1 to A16 of the light source 4A and all the light emitting sections B1 to B16 of the light source 4B while preventing the light emitting section of the light source 4A and the light emitting section of the light source 4B, which irradiate the irradiation sections that form the overlapping region 313 with light beams, from being simultaneously turned on. It should be noted that the control unit 8 turns on all the light emitting sections A1 to A16 of the light source 4A and all the light emitting sections B1 to B16 of the light source 4B by turning on, with a temporal shift, the light emitting section of the light source 4A and the light emitting section of the light source 4B, which irradiate the irradiation sections that form the overlapping region 313 with light beams. As a result, all the irradiation sections C1 to C16 of the irradiation surface 311 and all the irradiation sections D1 to D16 of the irradiation surface 312 are irradiated with light beams, and the entire irradiation surface 310 is irradiated with light without any defect.
Here, in a case where the aspect is adopted in which the light emitting section of the light source 4A and the light emitting section of the light source 4B, which irradiate the irradiation sections that form the overlapping region 313 with light beams, are prevented from being simultaneously turned on, an order in which the light emitting sections A1 to A16 of the light source 4A and the light emitting sections B1 to B16 of the light source 4B are turned on is not limited.
The control unit 8 may sequentially turn on the light emitting sections A1 to A16 of the light source 4A and the light emitting sections B1 to B16 of the light source 4B one by one. In this example, the control unit 8 turns on the light emitting sections B1 to B16 of the light source 4B, and then turns on the light emitting sections A1 to A16 of the light source 4A. It should be noted that, in this example, the light emitting sections A1 to A16 of the light source 4A and the light emitting sections B1 to B16 of the light source 4B are not simultaneously turned on.
Specifically, as shown in
As a result, all the irradiation sections C1 to C16 and D1 to D16 of the irradiation surface 310 are irradiated with light.
In addition, in a case where the control unit 8 does not simultaneously turn on the light emitting section of the light source 4A and the light emitting section of the light source 4B, which irradiate the irradiation sections that form the overlapping region 313 with light beams, any light emitting section of the light source 4A and any light emitting section of the light source 4B may be simultaneously turned on.
In the example shown in
Further, the control unit 8 turns on the light emitting section A15 of the light source 4A that irradiates the overlapping portion E3 of the overlapping region 313 with light, and does not turn on the light emitting section B3 of the light source 4B that irradiates the overlapping portion E3 with light. In addition, the control unit 8 turns on the light emitting section A16 of the light source 4A that irradiates the overlapping portion E4 of the overlapping region 313 with light, and does not turn on the light emitting section B4 of the light source 4B that irradiates the overlapping portion E4 with light.
In this example, the irradiation sections C15 and C16 where the light emitting sections A15 and A16 of the light source 4A are turned on and the light is applied, and the irradiation sections D1 and D2 where the light emitting sections B1 and B2 of the light source 4B are turned on and the light is applied are examples of a first irradiation section.
In addition, the irradiation sections C13 and C14 where the light emitting sections A13 and A14 of the light source 4A are not turned on and the light is not applied, and the irradiation sections D3 and D4 where the light emitting sections B3 and B4 of the light source 4B are not turned on and the light is not applied are examples of a second irradiation section.
In the example shown in
After the control unit 8 simultaneously turns on the light emitting sections A1, A2, A5, A6, A11, A12, A15, and A16 of the light source 4A and the light emitting sections B1, B2, B5, B6, B11, B12, B15, and B16 of the light source 4B, the control unit 8 turns off these light emitting sections. Then, the remaining light emitting sections A3, A4, A7 to A10, A13, and A14 of the light source 4A and the remaining light emitting sections B3, B4, B7 to B10, B13, and B14 of the light source 4B are simultaneously turned on.
As a result, all the irradiation sections C1 to C16 and D1 to D16 of the irradiation surface 310 are irradiated with light.
As described above, in the present exemplary embodiment, in a case where the light emitting section of one light source that irradiates the first irradiation section forming the overlapping region 313 of the irradiation surface 310 with light is turned on, and the light emitting section of the other light source that irradiates the second irradiation section forming the overlapping region 313 with light is not turned on, the light emitting sections that irradiate, with light beams, the irradiation sections other than the first irradiation section and the second irradiation section are turned on. As a result, a time required to irradiate all the irradiation sections of the irradiation surface 310 with light beams may be shortened, as compared with a case where, for example, the light emitting sections that irradiate, with light beams, the irradiation sections other than the first irradiation section and the second irradiation section are not simultaneously turned on.
In Exemplary Embodiment 1 and Exemplary Embodiment 2 described above, a case where the light emitting unit 4 has two light sources 4A and 4B as the plurality of light sources has been described as an example. However, the light emitting unit 4 may have three or more light sources as the plurality of light sources. Hereinafter, as Exemplary Embodiment 3 of the present invention, an aspect in which the light emitting unit 4 has four light sources 4K, 4L, 4M, and 4N will be described. The same reference numerals are used for the same configurations as in Exemplary Embodiment 1 and Exemplary Embodiment 2 described above, and the detailed description thereof will be omitted here.
Details will be described below, but in
The light emitting unit 4 according to the present exemplary embodiment has a light source 4K that irradiates the irradiation region 100K with light, a light source 4L that irradiates the irradiation region 100L with light, a light source 4M that irradiates the irradiation region 100M with light, and a light source 4N that irradiates the irradiation region 100N with light.
In the light emitting unit 4, the light sources 4K to 4N are arranged in order from the upper left side (the end in the −x direction and the +y direction) to the lower right side (the end in the +x direction and the −y direction) in
In this example, in a case where the light source 4K is used as a first light source, the light source 4L arranged in the +x direction, which is an example of a first direction, with respect to the light source 4K is an example of a second light source. In addition, the light source 4M arranged in the −y direction, which is an example of a second direction, with respect to the light source 4K is an example of a third light source.
In
In addition, in
In addition, in
In
In addition, in
On the other hand, the center line 101K of the irradiation region 100K and the center line 101L of the irradiation region 100L, which are irradiated with the light beams from the light source 4K and the light source 4L arranged in the x direction, do not intersect each other. Similarly, the center line 101M of the irradiation region 100M and the center line 101N of the irradiation region 100N, which are irradiated with the light beams from the light source 4M and the light source 4N arranged in the x direction, do not intersect each other.
In addition, in
As described above, in a case where the light emitting unit 4 has three or more light sources, as long as center lines of the irradiation regions irradiated with light beams from at least two light sources selected from the plurality of light sources intersect each other, a combination of the light sources in which the center lines of the irradiation regions do not intersect each other may be included.
In the light emitting unit 4, the center lines of the irradiation regions irradiated with light beams from at least two light sources selected from the plurality of light sources intersect each other, so that the range in which the non-irradiation region, which is not irradiated with light from the light source, is formed may be narrowed as compared with a case where none of the center lines of the irradiation regions irradiated with light beams from the plurality of light sources intersect each other.
In a case where the light emitting unit 4 has a plurality of light sources of three or more, from the viewpoint of further narrowing the range in which the non-irradiation region is formed, for example, it is preferable that the center lines of the irradiation regions irradiated with light beams from the plurality of light sources intersect each other at one intersection portion.
For example, in the example shown in
On the other hand, the range in which the non-irradiation region which is not irradiated with light beams from the light source 4K and the light source 4L is formed is likely to be widened between the irradiation region 100K and the irradiation region 100L where the center line 101K and the center line 101L do not intersect each other. Similarly, the range in which the non-irradiation region which is not irradiated with light beams from the light source 4M and the light source 4N is formed is likely to be widened between the irradiation region 100M and the irradiation region 100N where the center line 101M and the center line 101N do not intersect each other.
On the other hand, as shown in
Hereinafter, the light emitting surfaces of the light emitting chip 41 included in the light sources 4K, 4L, 4M, and 4N will be referred to as light emitting surfaces 413, 414, 415, and 416, respectively.
As shown in
Specifically, in the light source 4K, the light emitting chip 41 and the lens 42 are disposed such that a center 413C of the light emitting surface 413 is located to be shifted in the −x direction and the +y direction with respect to the optical axis 420 of the lens 42. In addition, in the light source 4K, the light emitting chip 41 and the lens 42 are disposed such that a long side 413x located on the −y direction side overlaps the first straight line Lx of the lens 42 and a short side 413y located on the +x direction side overlaps the second straight line Ly of the lens 42 on the light emitting surface 413.
In addition, in the light source 4L, the light emitting chip 41 and the lens 42 are disposed such that a center 414C of the light emitting surface 414 is located to be shifted in the +x direction and the +y direction with respect to the optical axis 420 of the lens 42. In addition, in the light source 4L, the light emitting chip 41 and the lens 42 are disposed such that a long side 414x located on the −y direction side overlaps the first straight line Lx of the lens 42 and a short side 414y located on the −x direction side overlaps the second straight line Ly of the lens 42 on the light emitting surface 414.
In addition, in the light source 4M, the light emitting chip 41 and the lens 42 are disposed such that a center 415C of the light emitting surface 415 is located to be shifted in the −x direction and the −y direction with respect to the optical axis 420 of the lens 42. In addition, in the light source 4M, the light emitting chip 41 and the lens 42 are disposed such that a long side 415x located on the +y direction side overlaps the first straight line Lx of the lens 42 and a short side 415y located on the +x direction side overlaps the second straight line Ly of the lens 42 on the light emitting surface 415.
In addition, in the light source 4N, the light emitting chip 41 and the lens 42 are disposed such that a center 416C of the light emitting surface 416 is located to be shifted in the +x direction and the −y direction with respect to the optical axis 420 of the lens 42. In addition, in the light source 4N, the light emitting chip 41 and the lens 42 are disposed such that a long side 416x located on the ty direction side overlaps the first straight line Lx of the lens 42 and a short side 416y located on the −x direction side overlaps the second straight line Ly of the lens 42 on the light emitting surface 416.
As described above, in the light emitting unit 4 according to the present exemplary embodiment, the light emitting surface 413 of the light emitting chip 41 in the light source 4K, the light emitting surface 414 of the light emitting chip 41 in the light source 4L, the light emitting surface 415 of the light emitting chip 41 in the light source 4M, and the light emitting surface 416 of the light emitting chip 41 in the light source 4N overlap the first straight line Lx and the second straight line Ly of the lens 42. It should be noted that there is no gap between the relative positions of the light emitting surfaces 413, 414, 415, and 416 with respect to the lens 42.
As a result, the non-irradiation region which is not irradiated with the light beams from the light sources 4K to 4L is prevented from being formed between the irradiation regions 100K, 100L, 100M, and 100N on the +z direction side with respect to the intersection portion 103 where the center lines 101K, 101L, 101M, and 101N intersect each other.
Subsequently, as Exemplary Embodiment 4 of the present invention, an aspect in which the light emitting unit 4 has three light sources 4P, 4Q, and 4R will be described. The same reference numerals are used for the same configurations as in Exemplary Embodiment 1 to Exemplary Embodiment 3 described above, and the detailed description thereof will be omitted here.
In addition,
The light emitting unit 4 according to the present exemplary embodiment has a light source 4P that irradiates the irradiation region 100P with light, a light source 4Q that irradiates the irradiation region 100Q with light, and a light source 4R that irradiates the irradiation region 100R with light.
In the light emitting unit 4, the light sources 4P, 4Q, and 4R are arranged in order from the ty direction side to the −y direction. That is, the light source 4P is disposed on the +y direction side with respect to the light source 4Q, and the light source 4Q is disposed on the ty direction side with respect to the light source 4R.
In
In addition, as shown in
Further, in
As shown in
As a result, the range in which the non-irradiation region which is not irradiated with the light beams from the light sources 4P and 4Q is formed may be narrowed as compared with a case where none of the center lines 101P to 101R of the irradiation regions 100P to 100R that are irradiated with the light beams from the three light sources 4P to 4Q intersect each other. In
In addition, as shown in
On the other hand, as shown in
Further, in
In
As shown in
As a result, the range in which the non-irradiation region which is not irradiated with the light beams from the light sources 4P and 4Q is formed may be narrowed as compared with a case where none of the center lines 101P to 101R of the irradiation regions 100P to 100R that are irradiated with the light beams from the three light sources 4P to 4Q intersect each other.
As in Exemplary Embodiment 3, in a case where the light emitting unit 4 has three light sources 4P to 4R, from the viewpoint of further narrowing the range in which the non-irradiation region is formed, for example, it is preferable that the center lines 101P to 101R of the irradiation regions 100P to 100R intersect each other at one intersection portion 106.
For example, in the example of
On the other hand, in the example of
Here, the light sources 4K to 4N of Exemplary Embodiment 3 and the light sources 4P to 4R of Exemplary Embodiment 4 may be configured such that the light emitting surface of each light emitting chip 41 is divided into a plurality of light emitting sections, as with the light sources 4A and 4B of Exemplary Embodiment 2. In this case, as in Exemplary Embodiment 2, for example, it is preferable that the control unit 8 controls the light emission operation of each light emitting section such that the light beams are not simultaneously emitted to the plurality of irradiation sections forming the overlapping region on the irradiation surface that is irradiated with the light from the light source. It should be noted that, for example, it is preferable that the control unit 8 does not simultaneously turn on the plurality of light emitting sections that irradiate the irradiation sections forming the overlapping region with light beams.
As a result, the amount of light emitted to the target object in the overlapping region is prevented from being excessive.
In the above-described exemplary embodiments, the housing 44 of the light emitting unit 4 is illustrated as an example of a housing that accommodates a plurality of light sources of the light emitting unit 4, but the present invention is not limited to this. The housing that accommodates a plurality of light sources may be a housing of the optical device 3 that accommodates the light receiving unit 5, the light emission drive unit 6, and the light reception drive unit 7 in addition to the plurality of light sources. In addition, the housing that accommodates a plurality of light sources may be a housing of the distance measurement apparatus 1 that accommodates the control unit 8 in addition to the plurality of light sources, the light receiving unit 5, the light emission drive unit 6, and the light reception drive unit 7. In addition, in the housing that accommodates the plurality of light sources, the plurality of light sources need not be completely covered with a cover or the like, and the housing may have a gap or an opening as long as the housing has a structure to prevent the entry of the target object.
In the optical device 3 or the distance measurement apparatus 1, as described above, the intersection portion where the center lines of the light beams emitted from the plurality of light sources to the irradiation regions intersect each other need only be located inside the housings. As a result, the entry of the target object into the periphery of the center line where the amount of light emitted to the target object is likely to be excessive is prevented.
In addition, in the above-described exemplary embodiments, in the light emitting unit 4, the lens 42 that refracts the light emitted from the light emitting chip 41 has been described as an example of the optical system, but the optical system is not limited to the lens 42 as long as the optical system changes the traveling direction of the light emitted from the light emitting chip 41 to expand the irradiation range of the light. As the optical system, for example, a diffractive optical element (DOE) that changes an angle of incident light and emits the light may be used.
In addition, various modifications and alternative configurations are involved in the present invention without departing from the technical scope of the present invention.
(((1)))
A light emitting device comprising:
The light emitting device according to (((1))), further comprising:
The light emitting device according to (((1))) or (((2))),
The light emitting device according to (((3))),
The light emitting device according to (((3))),
The light emitting device according to any one of (((1))) to (((5))),
The light emitting device according to any one of (((1))) to (((6))),
The light emitting device according to (((7))),
The light emitting device according to any one of (((1))) to (((6))),
The light emitting device according to (((9))),
A light emitting device comprising:
A distance measurement apparatus comprising:
The distance measurement apparatus according to (((12))),
The foregoing description of the exemplary embodiments of the present invention has been provided for the purposes of illustration and description. It is not intended to be exhaustive or to limit the invention to the precise forms disclosed. Obviously, many modifications and variations will be apparent to practitioners skilled in the art. The embodiments were chosen and described in order to best explain the principles of the invention and its practical applications, thereby enabling others skilled in the art to understand the invention for various embodiments and with the various modifications as are suited to the particular use contemplated. It is intended that the scope of the invention be defined by the following claims and their equivalents.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2023-210101 | Dec 2023 | JP | national |
