Light source device, detection device and electronic device

Abstract

To provide a light source device which is superior in uniformity of illuminance of irradiation light.SOLUTION: A light source device (11) according to the present invention has a light source (20) having a plurality of light emission parts (21), and a projection optical system (15) for irradiation with light that the light source emits, a light emission quantity per unit area of a light emission region of the light source corresponding to an irradiation region relatively large in enlargement rate of the projection optical system being larger than that of a light emission region of the light source corresponding to an irradiation region relatively small in enlargement rate of the projection optical system.SELECTED DRAWING: Figure 7

Description

[Technical Field]

[0001] The present invention relates to a light source device, a detection device, and an electronic device. [Background technology]

[0002] In recent years, detection devices that irradiate an object with light, receive reflected light from the object, and detect the state of the object have been used in a variety of fields. For example, Patent Document 1 describes a lidar system that uses laser light to detect the presence of an object and measure the distance to the object. This lidar system uses a vertical cavity surface emitting laser (VCSEL) as a light source and has a light source device that irradiates light emitted by the VCSEL through a lens. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2007-214564 Summary of the Invention [Problem to be solved by the invention]

[0004] When light from a light source is expanded by a projection optical system to irradiate a wide area, the illuminance of the light on the irradiated surface may become non-uniform due to the influence of aberrations in the projection optical system. In conventional light source devices, no consideration has been given to addressing this issue and making the illuminance on the irradiated surface. However, in detection devices that receive reflected light and perform detection, projecting light from the light source device onto the irradiated surface with uniform illuminance is extremely important for improving detection accuracy.

[0005] The present invention has been made in response to the above-mentioned problem, and has an object to provide a light source device that has excellent uniformity in the illuminance of the emitted light. [Means for solving the problem]

[0006] The present invention is a light source device used in a detection device that irradiates light onto an object and receives the reflected light reflected by the object using a detection unit, and includes a light source having a plurality of light-emitting elements arranged two-dimensionally, and a light projection optical system that irradiates the light emitted by the light source, wherein the light projection optical system includes a focusing optical element having a shared lens that suppresses the divergence angle of the light emitted from the plurality of light-emitting elements of the light source, and an expanding optical element that expands the irradiation angle of the light that has passed through the focusing optical element and emits it. In one aspect, in an illumination area on an illumination surface from the light projecting optical system, the magnification rate of the projection optical system in a first illumination area of ​​the illumination area is greater in a second illumination area of ​​the illumination area, the plurality of light emitting elements include a first light emitting area corresponding to the first illumination area and a second light emitting area corresponding to the second illumination area, and the amount of light emitted per unit area of ​​the second light emitting area is greater than the amount of light emitted per unit area of ​​the first light emitting area. In one aspect, the intervals between adjacent light emitting elements are different in at least a part of the light source. [Effects of the Invention]

[0007] According to the present invention, by setting the light emission amount of the light source so as to eliminate variations in illuminance caused by the projection optical system, a light source device with excellent uniformity in the illuminance of the emitted light can be obtained. [Brief explanation of the drawings]

[0008] [Figure 1] 1 is a conceptual diagram showing a distance measuring device that is an embodiment of a detection device to which a light source device of the present invention is applied; [Figure 2] 1A and 1B are diagrams showing the reference state of a light projection optical system in a light source device, in which FIG. 1A shows the configuration of the light source device, and FIG. 1B shows the state of light irradiated onto an irradiation surface by the light source device. [Figure 3] 1A and 1B are diagrams showing the irradiation area adjustment state of the light projection optical system in the light source device, where FIG. 1A shows the configuration of the light source device, and FIG. 1B shows the irradiation state of light on the irradiation surface by the light source device. [Figure 4] FIG. 10 is a cross-sectional view showing a light source device having an adjustment mechanism. [Figure 5] FIG. 2 is a cross-sectional view showing a part of a light source of the light source device. [Figure 6] 10 is a graph showing the illuminance distribution on the irradiation surface when a plurality of light-emitting units of a light source are arranged at uniform intervals and when a plurality of light-emitting units are arranged in a sparsely-packed arrangement. [Figure 7] FIG. 10 is a diagram showing a configuration in which a plurality of light-emitting units are arranged in a sparsely packed manner in the light source of the light source device. [Figure 8]10 is a graph showing the illuminance distribution on the irradiation surface when a plurality of light-emitting units of a light source are caused to emit light with a uniform light emission amount and when a plurality of light-emitting units are caused to emit light with different light emission amounts. [Figure 9] 10A and 10B are diagrams showing a configuration in which the light source of the light source device has different light emission intensities for a plurality of light emitting units. [Figure 10] FIG. 10 is a diagram showing an example of the installation range of a plurality of light-emitting units in a light source of a light source device. [Figure 11] 1A and 1B are diagrams showing the light irradiation area on the irradiation surface, where (A) shows the case where light emitting units are arranged over the entire rectangular light emitting surface, and (B) shows the case where light emitting units are arranged in an elliptical shape. [Figure 12] FIG. 10 is a diagram showing an example in which the light source device is applied to a detection device for inspecting an article. [Figure 13] FIG. 10 is a diagram showing an example in which a detection device having a light source device is applied to a movable device. [Figure 14] FIG. 10 is a diagram showing an example in which a detection device having a light source device is applied to a portable information terminal. [Figure 15] FIG. 10 is a diagram illustrating an example in which a detection device having a light source device is applied to a driving assistance system for a moving object. [Figure 16] FIG. 10 is a diagram showing an example in which a detection device having a light source device is applied to an autonomous driving system for a moving object. DETAILED DESCRIPTION OF THE INVENTION

[0009] Hereinafter, an embodiment to which the present invention is applied will be described with reference to the drawings. Fig. 1 shows an overview of a distance measuring device 10. The distance measuring device 10 is a TOF (Time Of Flight) distance measuring device that projects (irradiates) pulsed light from a light source device 11 onto a detection object 12, receives reflected light from the detection object 12 with a light receiving element 13, and measures the distance to the detection object 12 based on the time required for the reflected light to be received.

[0010] As shown in Fig. 1, the light source device 11 has a light source 14 and a light projection optical system 15. Light emission from the light source 14 is controlled by a current sent from a light source drive circuit 16. The light source drive circuit 16 transmits a signal to a signal control circuit 17 when the light source 14 emits light. The light projection optical system 15 is an optical system that spreads (diverges) the light emitted from the light source 14 and projects it onto the detection target 12.

[0011] Light emitted from the light source device 11 and reflected by the detection object 12 is guided to the light receiving element 13 through a light receiving optical system 18, which has a light collecting function. The light receiving element 13 is composed of a photoelectric conversion element, and the light received by the light receiving element 13 is photoelectrically converted and sent as an electrical signal to a signal control circuit 17. The signal control circuit 17 calculates the distance to the detection object 12 based on the time difference between the light projection (light emission signal input from the light source drive circuit 16) and the light reception (light reception signal input from the light receiving element 13). Therefore, in the distance measuring device 10, the light receiving element 13 functions as a detection unit that detects the light emitted from the light source device 11 and reflected by the detection object 12. The signal control circuit 17 also functions as a calculation unit that acquires information about the distance to the detection object 12 based on the signal from the light receiving element 13 (detection unit).

[0012] 2(A) and 3(A) show the configuration of the light source device 11. The light source 14 (FIG. 1) described above is provided with a surface-emitting laser 20, and the surface-emitting laser 20 is provided with a plurality of surface-emitting laser elements 21 arranged in a predetermined positional relationship on an emission surface P1. The surface-emitting laser 20 is an example of a light source in the present invention, and the surface-emitting laser element 21 is an example of a light-emitting unit in the present invention. The surface-emitting laser element 21 in this embodiment is a vertical cavity surface-emitting laser (hereinafter referred to as VCSEL) that emits light in a direction perpendicular to a substrate.

[0013] FIG. 5 shows a partial cross-sectional structure of a surface-emitting laser 20 corresponding to an individual surface-emitting laser element 21. A lower multilayer reflector 24D, a lower spacer layer 25D, an active layer 26, an upper spacer layer 25U, an upper multilayer reflector 24U, and a contact layer 23 are stacked on a substrate 22. A current confinement layer 27 is formed in the upper multilayer reflector 24U. The current confinement layer 27 is composed of a current passing region 27a and a current passage suppression region 27b surrounding the current passing region 27a. A lower electrode 28D is disposed at the bottom of the substrate 22, and an upper electrode 28U is disposed on the top. The inside of the upper electrode 28U is insulated by an insulator 29. The upper electrode 28U contacts the peripheral portion of the contact layer 23, and the central portion of the contact layer 23 is open.

[0014] When current is applied to the active layer 26 from each electrode 28U, 28D, it is amplified by the upper multilayer reflector 24U and the lower multilayer reflector 24D of the stacked structure, resulting in laser light oscillation. The emission intensity of the laser light changes depending on the magnitude of the applied current. The current confinement layer 27 increases the efficiency of the amount of current applied to the active layer 26 and lowers the oscillation threshold. As the current passing region 27a of the current confinement layer 27 becomes larger (wider), the maximum amount of current that can be applied increases, and the maximum output of the laser light that can be oscillated increases, but on the other hand, there is a characteristic that the oscillation threshold also increases.

[0015] Compared to edge-emitting lasers, VCSELs have the advantage of being easier to make two-dimensional light-emitting elements and enabling high-density arrangement of light-emitting elements to produce multi-point beams. VCSELs also offer a high degree of freedom in the layout of multiple light-emitting elements, allowing light-emitting elements to be placed anywhere on the substrate, excluding structural constraints such as electrode placement.

[0016] As shown in FIGS. 2A and 3A, the projection optical system 15 has a condenser lens 30, which is a condensing optical element, and a projection lens 31, which is a magnifying optical element. The condenser lens 30 is a lens with positive power, and is able to suppress the divergence angle of light emitted from each surface-emitting laser element 21 of the surface-emitting laser 20, thereby forming a conjugate image of each surface-emitting laser element 21. The projection lens 31 is a lens with negative power, and expands the irradiation angle of the light that has passed through the condenser lens 30 before emitting it, projecting the light onto an irradiation area that is wider than the light-emitting surface P1 of the surface-emitting laser 20. The curvature of the lens surface of the projection lens 31 determines the range of the irradiation area and the degree of magnification of the conjugate image.

[0017] The configuration of the projection optical system in the present invention is not limited to the examples shown in FIGS. 2A and 3A. The focusing optical element constituting the projection optical system 15 may be any element capable of suppressing the divergence angle of light from the light source (surface-emitting laser 20), and may be a diffraction grating or the like in addition to a lens. When a lens is used as the focusing optical element, it may be a common lens capable of transmitting light from multiple surface-emitting laser elements 21, or a microlens array having multiple lenses corresponding to each surface-emitting laser element 21. The projection optical element in the projection optical system 15 may be any element capable of expanding light, and may be a biconcave lens, a negative meniscus lens, a diffuser, or any other element. When a lens is used in either the focusing optical element or the projection optical element, the number of lenses arranged in the optical axis direction may be a single lens, or a lens group consisting of multiple lenses may be used.

[0018] 2(A) shows the light source device 11 in a state in which the focal length of the condenser lens 30 is equal to the distance from the light-emitting surface P1 of the surface-emitting laser 20 to the condenser lens 30. This state is defined as the reference state of the light projection optical system 15 in the light source device 11. In the reference state of the light projection optical system 15, the light from each surface-emitting laser element 21 of the surface-emitting laser 20 is collimated by the condenser lens 30, and after passing through the condenser lens 30, a conjugate image of each surface-emitting laser element 21 is formed at any position on the optical path. In other words, the light-emitting surface P1 and the irradiation surface P2 are close to being in a conjugate relationship. Note that the irradiation surface P2 is a virtual plane set to make the optical state easier to understand, and the actual detection target 12 is not limited to being flat and may have various shapes.

[0019] FIG. 2B shows the irradiation area on the irradiation surface P2 in the reference state of the projection optical system 15. In the surface-emitting laser 20, there are gaps between the multiple surface-emitting laser elements 21, so in the reference state where conjugate images of the surface-emitting laser elements 21 are formed, discrete irradiation areas E1 (with gaps between them) appear on the irradiation surface P2. More specifically, the irradiation area E1 is an area on the irradiation surface P2 that is irradiated with light, and multiple irradiation areas E1 exist in a positional relationship corresponding to the arrangement of the multiple surface-emitting laser elements 21 of the surface-emitting laser 20. Between the individual irradiation areas E1, there are non-irradiation areas E2 that have lower illuminance (are not irradiated with light) compared to the irradiation area E1. The non-irradiation areas E2 are areas corresponding to the gaps between the multiple surface-emitting laser elements 21 of the surface-emitting laser 20. In other words, in the reference state of the projection optical system 15, the illuminance on the irradiation surface P2 becomes discretely strong, and uniformity of illuminance cannot be obtained.

[0020] FIG. 3(A) shows a state in which the condenser lens 30 is slightly shifted toward the object side (the side closer to the light-emitting surface P1) in the optical axis direction from the reference state (FIG. 2(A)) of the light projection optical system 15. This state is referred to as the irradiation area adjustment state of the light projection optical system 15 in the light source device 11. In the irradiation area adjustment state, by shifting the condenser lens 30, the light from each surface-emitting laser element 21 is not completely collimated but diverges, and the image of each surface-emitting laser element 21 becomes wider than in the reference state. As a result, as shown in FIG. 3(B), a full-area irradiation area E3 is obtained on the irradiation surface P2, where light is irradiated so as to fill the areas corresponding to the gaps between the multiple surface-emitting laser elements 21.

[0021] The amount by which the condenser lens 30 needs to be shifted from the reference state to reach the adjusted illumination area state varies depending on the specifications of the projection optical system 15 and the surface-emitting laser 20, as well as various other conditions. In the configuration of this embodiment, a wide-angle, uniformly illuminated entire area E3 can be obtained by shifting the condenser lens 30 toward the object side (the side closer to the light-emitting surface P1) by 15% to 24% of the distance from the light-emitting surface P1 of the surface-emitting laser 20 to the condenser lens 30 in the reference state (corresponding to the focal length of the condenser lens 30). If the amount by which the condenser lens 30 is tilted falls below the lower limit (15%) of the above range, the illuminated area on the illuminated surface P2 corresponding to each surface-emitting laser element 21 narrows, resulting in the appearance of a non-illuminated area E2 as shown in FIG. 2B. If the amount by which the condenser lens 30 is tilted exceeds the upper limit (24%) of the above range, the angle of incidence of light to the projection lens 31 becomes too large, which increases the influence of aberrations in the illuminated area on the illuminated surface P2 and may impair the uniformity of the illumination.

[0022] In addition to the above-mentioned method of tilting the position of the condenser lens 30 in the optical axis direction in the projection optical system 15, a method of changing the curvature of the lens surface of the projection lens 31 can also be used to achieve projection that does not generate the non-irradiated area E2. More specifically, the conjugate images of each surface-emitting laser element 21 are made incident on the projection lens 31, and the images of each surface-emitting laser element 21 are expanded by setting the curvature of the lens surface of the projection lens 31 itself. Then, a projection lens 31 that can obtain an appropriate irradiation range (full-area irradiation area E3) that does not include the non-irradiated area E2 is selected. This method allows operation by simply replacing the projection lens 31 according to the desired irradiation range without changing the combination and arrangement of the surface-emitting laser 20 and the condenser lens 30, thereby reducing the workload involved in setting and adjustment.

[0023] In addition, to adjust the irradiation area by the projection optical system 15, it is possible to use a combination of the method of shifting the optical axis direction position of the focusing lens 30 and the method of changing the curvature of the lens surface of the projection lens 31 (replacing the projection lens 31).

[0024] 1, the shape and arrangement of the light receiving element 13 (FIG. 1) correspond to the irradiation area of ​​the light projected from the light source device 11. This maintains a correlation between the light emitted from each surface-emitting laser element 21 of the surface-emitting laser 20 and the light reflected by the detection object 12 and received by the light receiving element 13, allowing accurate detection (distance measurement) to be performed for each irradiation area corresponding to each surface-emitting laser element 21.

[0025] In order to obtain the entire illuminated area E3 as shown in Fig. 3(B), the position of the projection optical system 15 constituting the light source device 11 must be appropriately positioned relative to the position of the surface-emitting laser 20 according to the design value. For example, if the position of the condenser lens 30 constituting the projection optical system 15 is shifted in the optical axis direction relative to the design value, a conjugate image of each surface-emitting laser element 21 may be formed on the illuminated surface P2 as shown in Fig. 2(B), which may increase the non-illuminated area E2 on the illuminated surface P2. The projection lens 31 constituting the projection optical system 15 also needs to be positioned according to the design value.

[0026] Furthermore, if the positions of the light projecting optical system 15 and the surface-emitting laser 20 are misaligned in a direction perpendicular to the optical axis, the emission angle of the light emitted from the light source device 11 will also be misaligned. If the deviation in the emission angle of the light emitted from the light source device 11 becomes large relative to the angle of view of the light-receiving optical system 18 (FIG. 1), the non-irradiated range where reflected light is not received by the light-receiving optical system 18 will increase, and as a result, the range that can be measured by the distance measuring device 10 will be narrowed.

[0027] In order to prevent this state from occurring and to obtain the performance as designed, a light source device 11 equipped with an adjustment mechanism for adjusting the positions of optical elements is shown in Fig. 4. The light source device 11 shown in Fig. 4 is equipped with a first position adjustment unit 80 that supports the condenser lens 30 so that its position can be adjusted, a second position adjustment unit 81 that supports the projection lens 31 so that its position can be adjusted, and a third position adjustment unit 82 that supports the surface-emitting laser 20 so that its position can be adjusted relative to the projection optical system 15.

[0028] The first position adjustment unit 80 will now be described. The condensing lens 30 is held inside a lens holder 83, which is disposed inside a condensing lens barrel 84. The lens holder 83 is supported via a movable unit 85 so as to be movable in the optical axis direction relative to the condensing lens barrel 84. The movable unit 85 has a female thread (helicoid) formed on the inner peripheral surface of the condensing lens barrel 84, and a male thread on the outer peripheral portion of the lens holder 83 is screwed into the female thread. The lens holder 83 can be moved in the optical axis direction along the female thread of the movable unit 85 while rotating around the optical axis of the condensing lens 30, thereby adjusting its position. The range in which the movable unit 85 is formed in the optical axis direction (the range in which the female thread is formed on the condensing lens barrel 84) shown in FIG. 4 is the movable range of the condensing lens 30.

[0029] The second position adjustment unit 81 will now be described. The projection lens 31 is held inside a lens holder 86, which is disposed inside a projection lens barrel 87. The projection lens barrel 87 is attached to the outside of the condenser lens barrel 84, and the central axis of the condenser lens barrel 84 and the central axis of the projection lens barrel 87 are positioned coaxially. The lens holder 86 is supported via a movable unit 88 so as to be movable in the optical axis direction relative to the projection lens barrel 87. The movable unit 88 has a female thread (helicoid) formed on the inner peripheral surface of the projection lens barrel 87, and a male thread on the outer periphery of the lens holder 86 is screwed into the female thread. The lens holder 86 can move in the optical axis direction along the female thread of the movable unit 88 while rotating around the optical axis of the projection lens 31, thereby adjusting its position. The range in which the movable portion 88 shown in FIG. 4 is formed in the optical axis direction (the range in which the female screw is formed in the projection lens barrel 87) is the range in which the projection lens 31 can move.

[0030] Note that first position adjustment unit 80 and second position adjustment unit 81 may be any unit capable of precisely controlling the position of lens holder 83, and are not limited to the above-described movable unit 85 and screw mechanism like movable unit 85. As a modified example, a cam (cam groove) instead of a female thread may be formed on the circumferential surface of collecting lens barrel 84 or the circumferential surface of projector lens barrel 87, and cam followers may be provided on lens holder 83 or lens holder 86, and the cam followers may be guided by the cams to move lens holder 83 or lens holder 86 in the optical axis direction. Alternatively, a configuration may be adopted in which lens holder 83 or lens holder 86 is movably supported by a guide portion (guide shaft, guide groove, etc.) extending in the optical axis direction, lens holder 83 or lens holder 86 is screwed onto a feed screw extending in the optical axis direction, and lens holder 83 or lens holder 86 is guided by the guide portion and moves in the optical axis direction by rotation of the feed screw. The driving force for moving the lens holder 83 and the lens holder 86 in the optical axis direction may be applied manually or by a driving means such as a motor.

[0031] If the positions of the focusing lens 30 and the projecting lens 31 deviate from the design values, the positions can be adjusted using the first position adjustment unit 80 and the second position adjustment unit 81, thereby easily achieving illumination in the full illumination area E3 (Figure 3(B)) on the illumination surface P2, which has no non-illuminated areas.

[0032] The third position adjustment unit 82 will now be described. The surface-emitting laser 20 is supported on an electronic circuit board 90. Elements necessary for driving the surface-emitting laser 20, such as the light source drive circuit 16 (FIG. 1), are mounted on the electronic circuit board 90. The electronic circuit board 90 is supported via an adjustment mechanism 91 relative to the condenser lens barrel 84 so as to be movable in at least two different directions perpendicular to the optical axis. By moving the electronic circuit board 90 relative to the condenser lens barrel 84, the position of the surface-emitting laser 20 changes on a plane perpendicular to the optical axis (i.e., along the light-emitting surface P1 shown in FIG. 2(A) and FIG. 3(A)). The adjustment mechanism 91 has an opening in the center where the surface-emitting laser 20 is located, so as not to block the light emitted from each surface-emitting laser element 21.

[0033] The configuration of the adjustment mechanism 91 in the third position adjustment unit 82 can be selected as appropriate. As an example, the adjustment mechanism 91 is configured with a two-stage moving stage. The first-stage moving stage and the second-stage moving stage in the adjustment mechanism 91 are combined so as to be relatively movable along a first guide portion (guide shaft, guide groove, etc.) extending in a first direction perpendicular to the optical axis. The first-stage moving stage is fixed to the electronic circuit board 90. The second-stage moving stage is supported so as to be movable relative to the condenser lens barrel 84 along a second guide portion (guide shaft, guide groove, etc.) extending in a second direction (a direction different from the first direction) perpendicular to the optical axis. With this configuration, the positional relationship between the electronic circuit board 90 and the condenser lens barrel 84 (and the projector lens barrel 87) can be changed in any direction perpendicular to the optical axis. The driving force for moving each moving stage constituting the adjustment mechanism 91 in the direction perpendicular to the optical axis may be applied manually or by a driving means such as a motor.

[0034] As another example of the third position adjustment unit 82, an insertion unit is provided that is fixed to the electronic circuit board 90 and inserted into the condenser lens barrel 84. The condenser lens barrel 84 is provided with three or more support units at different positions around the circumference, each of which has an adjustable amount of protrusion in the inner diameter direction. The position of the electronic circuit board 90 is determined by supporting the insertion unit with these support units. Then, by changing the relative amount of protrusion of each support unit in the inner diameter direction of the condenser lens barrel 84, the position of the electronic circuit board 90 with respect to the condenser lens barrel 84 can be adjusted in the direction perpendicular to the optical axis.

[0035] The condenser lens barrel 84 and the projector lens barrel 87 are configured to align the optical axis of the condenser lens 30 and the optical axis of the projector lens 31 that they support. Then, by using the third position adjustment unit 82 to adjust the positions of the surface-emitting laser 20 and the electronic circuit board 90 relative to the condenser lens barrel 84 and the projector lens barrel 87, it is possible to align the center of the surface-emitting laser 20 with respect to the optical axes of the condenser lens 30 and the projector lens 31. This prevents deviation in the emission angle of the light emitted from the light source device 11 and reduces the non-irradiated range from the light source device 11 relative to the light-receiving angle of view in the light-receiving optical system 18, thereby improving the distance measurement accuracy of the distance measuring device 10.

[0036] As described above, by adjusting the respective positional relationships of the surface-emitting laser 20, the focusing lens 30, and the projection lens 31 using the first position adjustment unit 80, the second position adjustment unit 81, and the third position adjustment unit 82, it is possible to easily correct the mounting deviation of each part of the light source device 11 from the design value and the positional deviation of each part of the light source device 11 that occurs over time as the user uses it.

[0037] In the light source device 11 of FIG. 4, the first position adjustment unit 80 and the second position adjustment unit 81 adjust the position in the optical axis direction, and the third position adjustment unit 82 adjusts the position in the direction perpendicular to the optical axis, but the direction of adjustment by each adjustment unit is not limited to the form of FIG. 4. For example, the first position adjustment unit 80 and the second position adjustment unit 81 may be provided with a means for adjusting the position of the condenser lens 30 and the projector lens 31 in the direction perpendicular to the optical axis. Alternatively, the third position adjustment unit 82 may be provided with a means for adjusting the position of the surface-emitting laser 20 and the electronic circuit board 90 in the optical axis direction. Furthermore, instead of providing all of the first position adjustment unit 80, the second position adjustment unit 81, and the third position adjustment unit 82, only one of the position adjustment units may be selected and installed.

[0038] However, when the light from each surface-emitting laser element 21 of the surface-emitting laser 20 is expanded to a wide angle by the light projection optical system 15, the image on the irradiation surface P2 is distorted due to the influence of distortion aberration. That is, the magnification rate of the image differs depending on the irradiation area. Then, even when light is projected onto the entire irradiation area E3 as described above, uneven illuminance (variation in illuminance due to differences in areas on the irradiation surface P2) occurs due to the distortion of the image surface. This uneven illuminance is caused by the aberration of the light projection optical system 15 itself, which expands and irradiates light, and can occur in both the reference state of FIG. 2(A) and the irradiation area adjustment state of FIG. 3(A).

[0039] Distortion aberrations include pincushion distortion, in which the central portion of the image is contracted and the peripheral portions are stretched, and barrel distortion, in which the central portion of the image is bulged and the peripheral portions are contracted. With pincushion distortion aberration, the closer the surface-emitting laser elements 21 are located on the periphery of the light-emitting surface P1 of the surface-emitting laser 20, the greater the distortion (stretching) of the image on the irradiation surface P2, and the lower the illuminance (light amount) per unit area. With barrel distortion aberration, the closer the surface-emitting laser elements 21 are located on the center of the light-emitting surface P1 of the surface-emitting laser 20, the greater the distortion (stretching) of the image on the irradiation surface P2, and the lower the illuminance (light amount) per unit area.

[0040] In the light source device 11 of this embodiment, the settings in the surface-emitting laser 20 prevent variations in illuminance on the irradiation surface P2 caused by aberration in the light-projecting optical system 15. That is, in the surface-emitting laser 20, the amount of light emitted per unit area in a light-emitting region corresponding to an irradiation region where the magnification ratio of the light-projecting optical system 15 is relatively large is made larger than the amount of light emitted per unit area in a light-emitting region corresponding to an irradiation region where the magnification ratio of the light-projecting optical system 15 is relatively small. Means for uniforming the illuminance include a first form in which the intervals between the multiple surface-emitting laser elements 21 are changed, and a second form in which the light emission amounts of the multiple surface-emitting laser elements 21 are made different.

[0041] We will now explain a first form of illuminance uniformity achieved by changing the spacing between the multiple surface-emitting laser elements 21. This setting example addresses the case where pincushion distortion occurs in the image on the irradiation surface P2 as a result of the light from the surface-emitting laser 20 being expanded over a wide angle by the projection optical system 15 and projected.

[0042] The illuminance distribution on the irradiation surface P2 when all adjacent surface-emitting laser elements 21 in the surface-emitting laser 20 are arranged at equal intervals is shown as illuminance distribution Tv1 in Fig. 6. The horizontal axis of the graph in Fig. 6 represents the horizontal angle, and the vertical axis represents the illuminance ratio on the irradiation surface P2 (the point with the highest illuminance is set to 100%).

[0043] The illuminance distribution Tv1 when the surface-emitting laser elements 21 are uniformly arranged has a mountain-like shape in which the intensity is strongest at the center of the illumination range and decreases toward the periphery due to the influence of distortion aberration in the projection optical system 15. In this illuminance distribution Tv1, the horizontal angle width corresponding to 80% of the peak illuminance, where the illuminance is the strongest, is 106°.

[0044] 7, the surface-emitting laser 20 is arranged in a sparsely packed manner (non-uniform spacing) such that the spacing between adjacent surface-emitting laser elements 21 is narrower toward the periphery than toward the center of the light-emitting surface P1. As a result, the number of surface-emitting laser elements 21 per unit area increases (the spacing density increases) on the corresponding light-emitting surface P1 side toward the periphery where the degree to which the image is enlarged (magnification rate) on the irradiation surface P2 increases, and therefore the uniformity of the illuminance on the irradiation surface P2 is improved compared to when the surface-emitting laser elements 21 are arranged at equal intervals.

[0045] As an example, in this embodiment, a plurality of surface-emitting laser elements 21 are arranged as follows: The surface-emitting laser 20 has a square light-emitting surface P1 with horizontal and vertical dimensions of 1.44 mm, and includes 21 surface-emitting laser elements 21 in each of the horizontal and vertical rows, for a total of 411 surface-emitting laser elements 21. Ten surface-emitting laser elements 21 are arranged on either side of a central surface-emitting laser element 21Q (see FIG. 7) located in the center both horizontally and vertically.

[0046] Seen from the central surface-emitting laser element 21Q, the distance to the adjacent surface-emitting laser element 21 is a1, the distance to the second surface-emitting laser element 21 is a2, and the distance to the nth surface-emitting laser element 21 is an (n=1, 2, ... m) If the maximum number of surface-emitting laser elements 21 that can be arranged in each of the horizontal and vertical rows is N=2m+1 (m≧1), and the maximum distance at which the surface-emitting laser elements 21 can be arranged is b (an=b), then the distance an satisfies the following relationship: an=b-α(N-1 / 2-n) β

[0047] In this embodiment, N=21, b=0.7 mm, and an=0.7 mm when n=10. Under these conditions, the values ​​of the constants α and β that make the illuminance on the irradiation surface P2 uniform were found to be α=0.05 and β=1.15 in both the horizontal and vertical directions. In both the horizontal and vertical directions, the distance between the surface-emitting laser element 21 located on the outermost side of the light-emitting surface P1 and the surface-emitting laser element 21 immediately inside it is 49.6 μm, which is the minimum value. The distance between adjacent surface-emitting laser elements 21 gradually increases toward the center, and the distance (a1) between the central surface-emitting laser element 21Q and the surface-emitting laser element 21 immediately outside it is 80 μm, which is the maximum value.

[0048] FIG. 6 shows the illuminance distribution Tw1 on the irradiation surface P2 when multiple surface-emitting laser elements 21 are arranged in a sparsely packed arrangement to satisfy the above conditions. Compared to the illuminance distribution Tv1 when the surface-emitting laser elements 21 are evenly arranged, this illuminance distribution Tw1 improves the intensity dropoff at the periphery, resulting in a generally uniform illuminance from the center to the periphery. In the illuminance distribution Tw when the surface-emitting laser elements 21 are arranged in a sparsely packed arrangement, the horizontal angular width corresponding to 80% of the illuminance of the strongest peak value is 143°. While FIG. 6 shows the horizontal illuminance distribution Tw, the sparsely packed arrangement of the surface-emitting laser elements 21 also improved the intensity dropoff at the periphery in the vertical direction, similar to the horizontal direction. Note that the above-described conditions and values ​​for the sparsely packed arrangement of the surface-emitting laser elements 21 are merely an example in this embodiment, and the appropriate conditions and values ​​for the sparsely packed arrangement will vary depending on the configuration and form of the light source and optical system.

[0049] The optimum value for the dense arrangement of the surface-emitting laser elements 21 can be calculated and set at the design stage according to the specifications of the projection optical system 15, the surface-emitting laser 20, and the like. That is, because the aberration in the projection optical system 15 is known during optical design, it is also possible to calculate the illuminance variation in the irradiation area that may be caused by the influence of this aberration. Furthermore, the more the area of ​​the light-emitting surface P1 of the surface-emitting laser 20 corresponds to an irradiation area where the image projected on the irradiation surface P2 is relatively enlarged (an irradiation area where the illuminance per unit area is low), the more the arrangement density of the surface-emitting laser elements 21 on the light-emitting surface P1 side is increased (by narrowing the interval between adjacent surface-emitting laser elements 21), thereby increasing the amount of emitted light per unit area and achieving a nearly uniform illuminance distribution. By calculating and designing the dense arrangement of the surface-emitting laser elements 21 based on the optical design of the projection optical system 15 using computer simulation, a surface-emitting laser 20 optimized for the projection optical system 15 can be produced without the need for measurements or adjustments.

[0050] Uniformity of illuminance due to the sparsely and densely arranged surface-emitting laser elements 21 can be achieved without changing the emission intensity of each surface-emitting laser element 21 in the surface-emitting laser 20, so there is no need to control the amount of current applied to each surface-emitting laser element 21. Therefore, it is possible to reduce the size of the light source drive circuit 16 that controls the current applied to the surface-emitting laser 20.

[0051] When barrel distortion occurs in the image on the irradiation surface P2, unlike the example shown in FIG. 7 which deals with pincushion distortion, the surface-emitting laser 20 is arranged in a sparsely packed manner such that the spacing between adjacent surface-emitting laser elements 21 is narrower in the central part of the light-emitting surface P1 than in the peripheral part.

[0052] In this embodiment, the intervals between adjacent surface-emitting laser elements 21 are varied in stages in both the horizontal and vertical directions. However, it is also possible to configure the surface-emitting laser elements 21 so that they have both a uniform interval and a variable interval. For example, it is also possible to make the intervals between the surface-emitting laser elements 21 uniform from the center of the light-emitting surface P1 to a predetermined range, and vary the intervals between the surface-emitting laser elements 21 only in the peripheral portion of the light-emitting surface P1. Alternatively, it is also possible to make the intervals between the surface-emitting laser elements 21 uniform from the periphery of the light-emitting surface P1 to a predetermined range, and vary the intervals between the surface-emitting laser elements 21 only in the central portion of the light-emitting surface P1. The extent of the intervals to be set in each region of the light-emitting surface P1 can be appropriately determined depending on factors such as the influence of distortion of the projection optical system 15.

[0053] Next, a second embodiment of illuminance uniformity will be described, in which the light emission amounts of the plurality of surface-emitting laser elements 21 of the surface-emitting laser 20 are made different. This setting example corresponds to a case in which pincushion distortion occurs in the image on the irradiation surface P2 as a result of the light from the surface-emitting laser 20 being spread over a wide angle by the light projection optical system 15 and projected. Note that the interval between adjacent surface-emitting laser elements 21 on the light-emitting surface P1 is constant.

[0054] The illuminance distribution on the irradiation surface P2 when the light emission amounts of the surface-emitting laser elements 21 in the surface-emitting laser 20 are made the same is shown in Fig. 8 as illuminance distribution Tv2. The horizontal axis of the graph in Fig. 8 represents the horizontal angle, and the vertical axis represents the illuminance ratio on the irradiation surface P2 (the point with the highest illuminance is set to 100%). By making the amount of current applied to each surface-emitting laser element 21 and the size of the current passing region 27a of the current confinement layer 27 the same, the light emission amounts of each surface-emitting laser element 21 become the same.

[0055] The illuminance distribution Tv2 when the light emission amounts of the surface-emitting laser elements 21 are the same has a mountain-like shape in which the intensity is strongest at the center of the illumination range and decreases toward the periphery due to the influence of distortion aberration in the projection optical system 15. In this illuminance distribution Tv2, the horizontal angular width corresponding to 80% of the peak illuminance, where the illuminance is the strongest, is 57°.

[0056] 9, the light-emitting surface P1 is divided horizontally into five regions F1 to F5, and the amount of current applied to the surface-emitting laser elements 21 is controlled to vary for each region. More specifically, the amount of current applied is increased stepwise from region F1 located in the center of the light-emitting surface P1 to regions F4 and F5 located in the peripheral regions, so that the average output of light emitted from each surface-emitting laser element 21 increases toward the periphery of the light-emitting surface P1. As a result, the amount of light emitted per unit area in the corresponding light-emitting region of the surface-emitting laser 20 increases toward the periphery, where the degree of image enlargement on the irradiation surface P2 increases. This improves the uniformity of illuminance on the irradiation surface P2 compared to when the amount of current applied to each surface-emitting laser element 21 is constant.

[0057] As an example, the amount of current applied to each surface-emitting laser element 21 was set to emit light with an average output of 1 W in the central region F1, 1.06 W in regions F2 and F3 immediately outside region F1, and 1.29 W in the most peripheral regions F4 and F5. Corresponding to these differences in the amount of current applied, the size of the current passing region 27a of the current confinement layer 27 was set to 9 μm in region F1, 9.2 μm in regions F2 and F3, and 10 μm in regions F4 and F5.

[0058] The illuminance distribution on the irradiation surface P2 when the amount of applied current for each of the regions F1 to F5 is set as described above is shown as illuminance distribution Tw2 in Figure 8. This illuminance distribution Tw2 improves on the decrease in intensity at the periphery compared to illuminance distribution Tv2 when the amount of applied current is constant, and the horizontal angle width corresponding to 80% of the illuminance at the peak value, the strongest illuminance, is 85°.

[0059] When barrel distortion occurs in the image on the irradiation surface P2, unlike the above example dealing with pincushion distortion, the amount of current applied to the surface-emitting laser element 21 is increased from the peripheral regions F4 and F5 to the central region F1 in the surface-emitting laser 20. In other words, the amount of light emitted per unit area is set to be large in the central region F1 and small in the peripheral regions F4 and F5.

[0060] The amount of current applied to each surface-emitting laser element 21 can be changed by controlling the light source drive circuit 16, so that it is possible to dynamically adjust the illuminance distribution after the light source device 11 is completed.

[0061] While the above method involves changing the amount of current applied to each surface-emitting laser element 21, the effect of uniforming the illuminance on the irradiation surface P2 can also be achieved by changing only the size of the current passing region 27a of the current confinement layer 27 while maintaining a constant amount of current applied to each surface-emitting laser element 21. Reducing the size of the current passing region 27a lowers the oscillation threshold of the surface-emitting laser element 21, thereby increasing the average output of light emitted when a constant amount of current is applied, compared to a surface-emitting laser element 21 with a relatively large current passing region 27a. Therefore, the size of the current passing region 27a of a surface-emitting laser element 21 located at a position on the light-emitting surface P1 where a larger amount of light is required is reduced. However, the size of the current passing region 27a must be set within a selectable range determined by the electrode structure of each surface-emitting laser element 21.

[0062] In this embodiment, the light-emitting surface P1 is divided into five regions F1 to F5 in the horizontal direction, and the light emission intensity of the surface-emitting laser elements 21 is made different in each region. Unlike this embodiment, it is also possible to divide the light-emitting surface P1 into a plurality of regions in the vertical direction and manage the light emission intensity of the surface-emitting laser elements 21, or to manage the light emission intensity of the surface-emitting laser elements 21 for each region divided into a grid pattern both horizontally and vertically. Furthermore, the range in which the light emission intensity of the surface-emitting laser elements 21 is made different may be set to a shape other than a grid pattern. Furthermore, when the number of surface-emitting laser elements 21 is small, it is also possible to control the light emission intensity of all the surface-emitting laser elements 21 to be different.

[0063] It is also possible to uniform the illuminance in the irradiation area by combining the first method (FIGS. 6 and 7) of changing the spacing between the multiple surface-emitting laser elements 21 (arranging them in a coarse-dense manner) and the second method (FIGS. 8 and 9) of varying the light emission amounts of the multiple surface-emitting laser elements 21, as explained above.

[0064] 10 and 11 show an example in which the shape of the irradiation area on the irradiation surface P2 is changed by setting the installation range of the surface-emitting laser element 21 on the light-emitting surface P1. This setting example corresponds to a case in which pincushion distortion occurs in the image on the irradiation surface P2 as a result of the light from the surface-emitting laser 20 being expanded over a wide angle by the projection optical system 15 and projected.

[0065] Fig. 11(A) shows the illumination area on the irradiation surface P2 when the surface-emitting laser elements 21 are arranged over the entire rectangular light-emitting surface P1. Although the configuration on the light-emitting surface P1 side corresponding to Fig. 11(A) is not shown, similar to the configuration shown in Fig. 7, the surface-emitting laser elements 21 are arranged in a sparsely packed manner such that the intervals between them are wider at the center of the light-emitting surface P1 and narrower at the periphery.

[0066] 11(A), the boundary where a large difference in illuminance occurs is conceptually shown by a two-dot chain line, and the outline K1 is the approximate outline of the illuminated area. As can be seen from this figure, due to the influence of distortion aberration of the projection optical system 15, distortion of the illuminated area is large in the peripheral part of the illuminated surface P2, especially near the four corners.

[0067] 10 shows a surface-emitting laser 20 in which the four corners of the rectangular light-emitting surface P1 are set as non-light-emitting portions H where no surface-emitting laser elements 21 are arranged, and the light-emitting portion formed by the plurality of surface-emitting laser elements 21 is set to have an elliptical shape as a whole. In the light-emitting portion (the installation range of the surface-emitting laser elements 21) set to an elliptical shape, the surface-emitting laser elements 21 are arranged in a sparsely packed manner with wider intervals at the center of the light-emitting surface P1 and narrower at the periphery. Note that the non-light-emitting portion H may be configured so that the structure of the surface-emitting laser element 21 as shown in FIG. 5 is not physically provided, or the structure of the surface-emitting laser element 21 may be provided but the element may be controlled not to emit light.

[0068] FIG. 11(B) shows the illuminance on the irradiation surface P2 when the installation range of the surface-emitting laser element 21 is set to an ellipse (FIG. 10). As in FIG. 11(A), the boundaries where large differences in illuminance occur are conceptually shown by two-dot chain lines, and the contour line K2 roughly defines the outline of the illumination area. By making the four corners of the light-emitting surface P1 non-light-emitting areas H, large distortions of the illumination at the four corners of the illumination surface P2 as in FIG. 11(A) do not occur, and an illumination area (contour line K2) with a nearly rectangular shape is formed. In addition, because the areas corresponding to the peripheral areas where the image is significantly stretched due to distortion are made non-light-emitting areas H on the light-emitting surface P1, variations in illuminance at the peripheral areas of the illumination area are also suppressed.

[0069] In this way, since the light-emitting surface P1 and the irradiation surface P2 correspond to each other, the shape of the irradiation area on the irradiation surface P2 can be changed by changing the setting of the range where the surface-emitting laser element 21 is installed on the light-emitting surface P1 side. Therefore, in the distance measuring device 10 (FIG. 1), by irradiating light from the light source device 11 so as to form an irradiation area corresponding to the shape of the light-receiving element 13, it is possible to avoid irradiating unnecessary areas and improve the light utilization efficiency.

[0070] As described above, in the light source device 11 to which the present invention is applied, the amount of light emitted per unit area of ​​the light-emitting region of the surface-emitting laser 20 is varied appropriately depending on the irradiation region so as to reduce variations in illuminance due to the influence of aberration in the light-projecting optical system 15. This results in a high-quality light source device 11 that achieves both wide-angle light projection onto the irradiation target and uniformity in illuminance. Furthermore, by projecting light from the light source device 11 with excellent uniformity in illuminance, it is possible to improve the detection accuracy of the distance measuring device 10 that uses the light source device 11 (or in general, detection devices including those for uses other than distance measurement).

[0071] Application examples in which the light source device 11 described above is used in various electronic devices will be described with reference to Figs. 12 to 16. A detection device 50 in these application examples is obtained by replacing the signal control circuit 17 of the distance measuring device 10 shown in Fig. 1 with the respective functional blocks described below, but the basic configuration is otherwise the same as that of the distance measuring device 10. In the detection device 50, the light receiving element 13 shown in Fig. 1 is a detection unit that detects light emitted from the light source device 11 and reflected by the detection target object 12. Note that in Figs. 12 to 16, functional blocks such as a determination unit provided in the detection device 50 are depicted outside the detection device 50 for convenience of drawing.

[0072] FIG. 12 shows an example application of a detection device 50 for inspecting items in a factory or the like. Light emitted from a light source device 11 of the detection device 50 is projected onto an irradiation area covering multiple items 51, and the reflected light is received by a detection unit (light-receiving element 13). Based on the information detected by the detection unit, a determination unit 52 determines the state of each item 51. Specifically, an image processing unit 53 generates image data (image information of the area illuminated by light from the light source device 11) based on an electrical signal photoelectrically converted by the light-receiving element 13, and the determination unit 52 determines the state of each item 51 based on the obtained image information. In other words, the light-receiving optical system 18 and the light-receiving element 13 in the detection device 50 function as an imaging means for capturing an image of the area illuminated by light from the light source device 11. Well-known image analysis such as pattern matching can be used to determine the state of the items 51 performed by the determination unit 52 based on the captured image information.

[0073] In the application example of FIG. 12, by using a detection device 50 (light source device 11) that can project light with uniform illuminance onto the irradiation area, illuminance variations are suppressed even when light is irradiated at a wide angle. As a result, many items 51 can be inspected simultaneously with high accuracy, improving inspection work efficiency. Furthermore, by using a detection device 50 that performs TOF detection, information can be obtained not only from the front side (the side facing the detection device 50) of each item 51, but also from the depth direction of each item 51. Therefore, compared to appearance inspection using existing imaging devices, it is easier to identify minute scratches, defects, three-dimensional shapes, etc. on the item 51, thereby improving inspection accuracy. Furthermore, because the light from the light source device 11 of the detection device 50 illuminates the irradiation area including the item 51 to be inspected, it can be used even in dark environments.

[0074] 13 shows an example of an application in which the detection device 50 is used to control the operation of a movable device. The movable device is an articulated arm 54, which has multiple arms connected by bendable joints and is equipped with a hand unit 55 at its tip. The articulated arm 54 is used, for example, on a factory assembly line, and grasps an object 56 with the hand unit 55 when inspecting, transporting, or assembling the object 56.

[0075] A detection device 50 is mounted on the articulated arm 54 immediately adjacent to the hand unit 55. The detection device 50 is disposed so that the direction of light projection coincides with the direction in which the hand unit 55 faces, and detects an object 56 and its surrounding area. The detection device 50 receives reflected light from an illuminated area including the object 56 with a light-receiving element 13, generates image data (takes an image) with an image processing unit 57, and determines various pieces of information about the object 56 based on the obtained image information with a determination unit 58. Specifically, the information detected by the detection device 50 includes the distance to the object 56, the shape of the object 56, the position of the object 56, and the relative positions of multiple objects 56 when multiple objects 56 exist. Then, based on the determination result by the determination unit 58, a drive control unit 59 controls the operation of the articulated arm 54 and the hand unit 55 to grasp or move the object 56.

[0076] 13, the same effect (improved detection accuracy) as that of the detection device 50 in Fig. 12 described above can be obtained with regard to the detection of the object 56 by the detection device 50. In addition, by mounting the detection device 50 on the articulated arm 54 (particularly, immediately adjacent to the hand unit 55), the object 56 to be grasped can be detected from a short distance, and the detection accuracy and recognition accuracy can be improved compared to detection from a long distance using an imaging device disposed at a position distant from the articulated arm 54.

[0077] 14 shows an example of application of the detection device 50 to user authentication of an electronic device. A portable information terminal 60, which is an electronic device, has a function for authenticating a user. The authentication function may be realized by dedicated hardware, or may be realized by a CPU (Central Processing Unit) that controls the portable information terminal 60 executing a program in a ROM (Read Only Memory) or the like.

[0078] When authenticating a user, light is projected from the light source device 11 of the detection device 50 mounted on the portable information terminal 60 toward the user 61 using the portable information terminal 60. The light reflected by the user 61 and their surroundings is received by the light receiving element 13 of the detection device 50, and image data is generated (image is captured) by the image processing unit 62. The determination unit 63 determines the degree of match between the image information of the user 61 captured by the detection device 50 and pre-registered user information, and determines whether the user is a registered user. Specifically, the shapes (contours and irregularities) of the user 61's face, ears, head, etc. are measured and can be used as user information.

[0079] 14, the same effect (improved detection accuracy) as that of the detection device 50 in FIG. 12 described above can be obtained with regard to the detection of the user 61 by the detection device 50. In particular, since the light source device 11 projects light at a wide angle with uniform illuminance and can detect information about the user 61 over a wide range, the amount of information required to recognize the user is greater than when the detection range is narrow, and recognition accuracy can be improved.

[0080] 14 shows an example in which the detection device 50 is mounted on a mobile information terminal 60, but user authentication using the detection device 50 can also be used in office automation equipment such as stationary personal computers and printers, building security systems, and the like. In terms of functionality, the detection device 50 can be used not only for personal authentication but also for scanning three-dimensional shapes such as faces. In this case, too, highly accurate scanning can be achieved by mounting the detection device 50 (light source device 11) that can project light at a wide angle with uniform illuminance.

[0081] 15 shows an example of application of the detection device 50 to a driving assistance system for a mobile body such as an automobile. The automobile 64 is equipped with a driving assistance function that can automatically perform some driving operations such as deceleration and steering. The driving assistance function may be realized by dedicated hardware, or may be realized by an ECU (Electronic Control Unit) that controls the electrical system of the automobile 64 executing a program such as a ROM.

[0082] Light is projected from the light source device 11 of the detection device 50 mounted inside the automobile 64 toward the driver 65 driving the automobile 64. The light reflected by the driver 65 and his surroundings is received by the light receiving element 13 of the detection device 50, and image data is generated (image is captured) by the image processing unit 66. A determination unit 67 determines information such as the face (expression) and posture of the driver 65 based on the image information of the captured image of the driver 65. Then, based on the determination result of the determination unit 67, a driving control unit 68 controls the brakes and steering wheels to provide appropriate driving assistance according to the situation of the driver 65. For example, control such as automatic deceleration and automatic stopping can be performed when inattentive driving or drowsy driving is detected.

[0083] 15, the same effect (improved detection accuracy) as that of the detection device 50 in FIG. 12 described above can be obtained with regard to detection of the state of the driver 65 by the detection device 50. In particular, since the light source device 11 projects light at a wide angle with uniform illuminance and can detect information about the driver 65 over a wide range, a larger amount of information can be obtained compared to when the detection range is narrow, and the accuracy of driving assistance can be improved.

[0084] FIG. 15 shows an example in which the detection device 50 is mounted on an automobile 64, but it can also be applied to moving bodies other than automobiles, such as trains and airplanes. Furthermore, in addition to detecting the face and posture of the driver or operator of the moving body, it can also be used to detect the state of passengers in the passenger seats and the state of the interior of the vehicle other than the passenger seats. In terms of functionality, it can also be used for personal authentication of the driver, similar to the application example of FIG. 14. For example, it is possible to control the operation of detecting a driver 65 using the detection device 50, and permitting the engine to start or the doors to lock and unlock only if the driver 65 matches pre-registered driver information.

[0085] Fig. 16 shows an application example in which the detection device 50 is used in an autonomous driving system for a mobile body. Unlike the application example in Fig. 15, in the application example in Fig. 16, the detection device 50 is used to sense an object outside the mobile body 70. The mobile body 70 is an autonomous mobile body that can travel automatically while recognizing the external situation.

[0086] A detection device 50 is mounted on a moving object 70, and the detection device 50 emits light in the direction of travel of the moving object 70 and its surrounding area. A desk 72 is installed in the direction of travel of the moving object 70 in a room 71, which is the area in which the moving object 70 moves. Of the light projected from a light source device 11 of the detection device 50 mounted on the moving object 70, light reflected by the desk 72 and its surroundings is received by a light receiving element 13 of the detection device 50, and an electrical signal obtained by photoelectric conversion is sent to a signal processing unit 73. The signal processing unit 73 calculates information about the layout of the room 71, such as the distance to the desk 72, the position of the desk 72, and surrounding conditions other than the desk 72, based on the electrical signal sent from the light receiving element 13. Based on this calculated information, a determination unit 74 determines the travel path and travel speed of the moving object 70, and based on the determination result of the determination unit 74, a driving control unit 75 controls the travel of the moving object 70 (such as the operation of the motor serving as the drive source).

[0087] 16, the same effect (improved detection accuracy) as that of the detection device 50 in FIG. 12 described above can be obtained with respect to layout detection of the room 71 by the detection device 50. In particular, since the light source device 11 projects light at a wide angle with uniform illuminance and can detect information about the room 71 over a wide range, a larger amount of information can be obtained compared to when the detection range is narrow, and the accuracy of the autonomous traveling of the mobile object 70 can be improved.

[0088] 16 shows an example in which the detection device 50 is mounted on an autonomous vehicle 70 that travels indoors 71, but it can also be applied to an autonomous vehicle that travels outdoors (so-called self-driving vehicles). It can also be applied to a driving assistance system for a vehicle that is not autonomous but is driven by a driver, such as an automobile. In this case, the detection device 50 can be used to detect the surrounding conditions of the vehicle, and the driver's driving can be assisted in accordance with the detected surrounding conditions.

[0089] Although the present invention has been described above based on the illustrated embodiment, the present invention is not limited to the above embodiment, and modifications and improvements are possible within the gist of the invention.

[0090] In the above embodiment, a surface-emitting laser 20 is used as the light source, in which a plurality of surface-emitting laser elements 21 are arranged in the horizontal and vertical directions to emit light from the surface as a whole. However, it is also possible to use a linear light source in which light-emitting regions are arranged only in a specific direction, such as the horizontal or vertical direction.

[0091] In addition to the VCSEL of the above embodiment, it is also possible to use an edge-emitting laser, a light-emitting diode (LED), etc. As described above, the VCSEL is advantageous in that it is easy to make the light-emitting region two-dimensional and has a high degree of freedom in arranging multiple light-emitting regions, but even when a light source other than the VCSEL is used, it is possible to obtain the same effects as the above embodiment by appropriately setting the arrangement and light emission amount of each light-emitting element. [Explanation of symbols]

[0092] 10: Distance measuring device 11:Light source device 13: Light receiving element (detection part) 14:Light source 15: Projection optical system 16: Light source driving circuit 17: Signal control circuit (calculation unit) 18: Light receiving optical system 20: Surface-emitting laser (light source) 21: Surface-emitting laser element (light-emitting part) 27: Current confinement layer 30: Condenser lens (light-collecting optical element) 31: Projection lens (magnifying optical element) 50:Detection device 54: Articulated arm (electronic device) 60: Portable information terminals (electronic devices) 64: Automobile (electronic equipment) 70: Mobile object (electronic equipment) 80: First position adjustment unit 81: Second position adjustment unit 82: Third position adjustment unit E1: Irradiation area E2: Non-irradiated area E3: Full irradiation area H: Non-light-emitting area P1: Light-emitting surface P2: Irradiation surface

Claims

1. A light source device used in a detection device that irradiates light onto an object and receives light reflected by the object by a detection unit, a light source including a plurality of light-emitting units arranged two-dimensionally, and a light projection optical system that irradiates the light emitted by the light source; The light projection optical system includes: a condensing optical element having a shared lens that reduces the divergence angle of light emitted from the plurality of light-emitting portions of the light source; a magnifying optical element that magnifies the illumination angle of the light that has passed through the focusing optical element and emits the light; and In an illumination area on an illumination surface from the light projection optical system, the magnification ratio of the light projection optical system in a second illumination area of ​​the illumination area is larger than the magnification ratio of the light projection optical system in a first illumination area of ​​the illumination area, the plurality of light-emitting units include a first light-emitting region corresponding to the first illumination region and a second light-emitting region corresponding to the second illumination region; A light source device, characterized in that the amount of light emitted per unit area of ​​the second light-emitting region is greater than the amount of light emitted per unit area of ​​the first light-emitting region.

2. A light source device used in a detection device that irradiates light onto an object and receives reflected light from the object by a detection unit, a light source including a plurality of light-emitting units arranged two-dimensionally, and a light projection optical system that irradiates the light emitted by the light source; The light projection optical system includes: a condensing optical element having a shared lens that reduces the divergence angle of light emitted from the plurality of light-emitting portions of the light source; a magnifying optical element that magnifies the illumination angle of the light that has passed through the focusing optical element and emits the light; and A light source device, characterized in that the intervals between adjacent light-emitting portions are different in at least a part of the light source.

3. 3. The light source device according to claim 1, wherein the magnifying optical element has a lens whose optical axis coincides with that of the lens of the light-collecting optical element.

4. 3. The light source device according to claim 1, further comprising a first position adjustment unit that is capable of moving the light-collecting optical element relative to the light source or the magnifying optical element.

5. The light source device according to claim 4 , wherein the first position adjustment unit is capable of adjusting the position of the light-collecting optical element at least in the optical axis direction.

6. 6. The light source device according to claim 1, further comprising a second position adjustment unit that is capable of moving the magnifying optical element relative to the light source or the focusing optical element.

7. 7. The light source device according to claim 1, further comprising a third position adjustment unit that is capable of moving the light source relative to the light projection optical system.

8. The light source device according to claim 7 , wherein the third position adjustment unit is capable of adjusting the position of the light source at least in a direction perpendicular to the optical axis.

9. The light source device according to claim 1 , wherein the light emitting portions of at least some of the light sources are different in light emission amount.

10. 10. The light source device according to claim 1, wherein the amount of current applied to the plurality of light-emitting elements is the same.

11. 11. The light source device according to claim 1, wherein the light source is one of a vertical cavity surface emitting laser, an edge emitting laser, and a light emitting diode.

12. The light source device according to any one of claims 1 to 11; The detection unit; A detection device comprising:

13. The detection device according to claim 12 , further comprising a calculation unit that acquires information about the distance to the object based on a signal from the detection unit.

14. 14. An electronic device to which information from the detection device according to claim 12 or 13 is input, the electronic device comprising a control unit that controls the electronic device based on the information from the detection device.

Images