Light-emitting device and distance measurement device

Abstract

[Problem] To attain miniaturization even when the number of capacitors is increased. [Solution] This light-emitting device comprises: a plurality of light-emitting elements disposed in a two-dimensional array and each having first and second terminals; M first wires extending in a first direction; and N second wires extending in a second direction crossing the first direction and respectively connected to the M first wires. The light-emitting device is provided with: a plurality of first terminal wires connected to the first terminals of the light emitting elements, and a plurality of second terminal wires which are electrically connected the second terminals of the light emitting elements and are each electrically connected to P of the light-emitting elements; a plurality of selection circuits for respectively selecting the light-emitting elements; a plurality of drive circuits for respectively driving the light-emitting elements; a plurality of capacitors for accumulating electric charges for causing a current to flow through the plurality of light-emitting elements; a first substrate on which the plurality of light-emitting elements are disposed; and a second substrate stacked on the first substrate and on which the plurality of drive circuits are disposed. The plurality of capacitors are disposed so that at least some of capacitors overlap the first substrate and the second substrate in a plan view.

Description

Light emitting device and distance measuring device

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

[0002] LiDAR (Light Detection and Ranging) is one method for obtaining distance information. With LiDAR, light is shone onto the object for which distance information is to be obtained, and the distance is estimated based on the light reflected from the object. LiDAR generally uses the ToF (Time of Flight) method, which measures the time it takes for light to travel through space. With the ToF method, distance information is obtained by measuring the time it takes for light emitted from a light-emitting device to hit the object and return.

[0003] Among distance measurement systems that employ the ToF method, a structure in which the light-emitting unit and light-receiving unit do not have any physically moving parts is called solid-state LiDAR. Solid-state LiDAR uses an array of light-emitting units to select light-emitting locations and project light onto the intended irradiation area. Light emitted by the light-emitting elements (also called light-emitting channels) located at the selected light-emitting locations is reflected by the target and received by the light-receiving elements corresponding to the light-emitting channels on the receiving side. The light-emitting unit of this light-emitting device uses a light source with laser diodes arranged in an array, a laser driver capable of matrix driving to drive the selected light-emitting channels, and a drive circuit, allowing only the desired light-emitting channel to emit light. When a multi-channel VCSEL is used as the light-emitting device, it can be driven individually and emit high-power, short-pulse light (see Patent Document 1).

[0004] Japanese Patent Application Publication No. 2020-96169

[0005] The light-emitting device described in Patent Document 1 includes a capacitor for each light-emitting element to pass current through each light-emitting element. Therefore, in a light-emitting device with a large number of light-emitting channels, such as a LiDAR, the increased number of capacitors restricts placement and complicates the routing of the wiring connected to the capacitors, increasing the absolute value and in-plane variation of parasitic inductance. This results in greater variation in light-emitting characteristics, such as the light-emitting power and light-emitting period, of each light-emitting element, making it impossible to achieve high-power and short pulses. Furthermore, when the number of light-emitting element channels is very large, the increased number of capacitors and wiring increases the size of the light-emitting module, making miniaturization difficult and increasing power consumption.

[0006] Therefore, the present disclosure provides a light emitting device and a distance measuring device that can be miniaturized even if the number of capacitors increases.

[0007] In order to solve the above problems, according to the present disclosure, there is provided a light emitting device including: a plurality of light emitting elements arranged in a two-dimensional array, each having a first and second terminal; a plurality of first terminal wirings including M first wirings (M is an integer of 2 or more) extending in a first direction and N second wirings (N is an integer of 2 or more) extending in a second direction intersecting the first direction and electrically connected to the M first wirings, respectively; a plurality of second terminal wirings electrically connected to the second terminals of the light emitting elements, each electrically connected to P (P is an integer of 2 or more) of the light emitting elements; a plurality of selection circuits respectively connected to one of the plurality of first terminal wirings and the plurality of second terminal wirings, and selecting corresponding light emitting elements; a plurality of drive circuits respectively connected to the other of the plurality of first terminal wirings and the plurality of second terminal wirings, and driving corresponding light emitting elements; a plurality of capacitors respectively connected to one of the first and second terminal wirings, and storing electric charges for flowing current through the plurality of light emitting elements; a first substrate on which the plurality of light emitting elements are arranged; a second substrate stacked on the first substrate and on which the plurality of drive circuits are arranged, wherein the plurality of capacitors are arranged so that, when viewed in a plane, at least a portion of the capacitors overlap the first substrate and the second substrate, N is an integer that is the same as or different from M, and P is an integer that is the same as or different from at least one of M and N.

[0008] The second substrate may include the plurality of capacitors.

[0009] The second substrate may have the capacitors arranged on a layer separate from the drive circuits.

[0010] The plurality of capacitors may be disposed in a wiring layer of the second substrate.

[0011] The first substrate may include the plurality of capacitors.

[0012] The first substrate may have the plurality of capacitors arranged in a layer separate from the plurality of light-emitting elements.

[0013] The plurality of capacitors may be disposed in a wiring layer of the first substrate.

[0014] The semiconductor device may further include a third substrate stacked between the first substrate and the second substrate, the third substrate having the plurality of capacitors.

[0015] The plurality of capacitors may be arranged on a surface of the second substrate opposite to a surface facing the first substrate.

[0016] The plurality of capacitors may be electrically connected to the one of the first and second terminal wirings by vias that penetrate the second substrate.

[0017] The plurality of capacitors may have a metal-insulator-metal (MIM) structure, a metal-oxide-metal (MOM) structure, a trench structure, or a wiring capacitance.

[0018] The capacitor may further include a capacitance selector that selects one of two or more capacitors each having a different capacitance, and the plurality of capacitors may include the capacitor selected by the capacitance selector.

[0019] The second substrate may include a power supply circuit that adjusts the voltage level of a reference voltage used to store charge in the plurality of capacitors.

[0020] According to the present disclosure, a display device includes: a plurality of light-emitting elements arranged in a two-dimensional array, each having a first and second terminal; a plurality of first terminal wirings including M first wirings (M is an integer of 2 or more) extending in a first direction and N second wirings (N is an integer of 2 or more) extending in a second direction intersecting the first direction and electrically connected to the M first wirings, respectively; a plurality of second terminal wirings electrically connected to the second terminals of the light-emitting elements, each electrically connected to P (P is an integer of 2 or more) of the light-emitting elements; a plurality of selection circuits respectively connected to one of the plurality of first terminal wirings and the plurality of second terminal wirings, and selecting corresponding light-emitting elements; a plurality of drive circuits respectively connected to the other of the plurality of first terminal wirings and the plurality of second terminal wirings, and driving corresponding light-emitting elements; a plurality of capacitors electrically connected to one of the first and second terminal wirings, and storing electric charges for flowing current through the plurality of light-emitting elements; a first substrate on which the plurality of light-emitting elements are arranged; A light emitting device is provided, comprising: a second substrate stacked on the first substrate and on which the plurality of drive circuits are arranged, the second substrate having a power supply circuit that adjusts the voltage level of a reference voltage used on at least a portion of the second substrate.

[0021] The power supply circuit may adjust the voltage level of the reference voltage used to store charge in the plurality of capacitors.

[0022] The power supply circuit may adjust the voltage level of the reference voltage based on a predetermined control signal.

[0023] The control signal may be a signal that controls at least one of a peak value, a pulse width, or a light emission timing of a light emission pulse waveform of the plurality of light emitting elements.

[0024] The control signal may be a signal that corrects for the ambient temperature of the plurality of light-emitting elements.

[0025] The control signal may be a signal that controls the light emission output of the plurality of light-emitting elements in accordance with the distance to an object.

[0026] According to the present disclosure, there is provided a distance measuring device including: a light emitting device that emits light toward an object; and a distance measuring unit that receives light reflected by the object and measures the distance to the object, wherein the light emitting device includes a plurality of light emitting elements arranged in a two-dimensional array, each having a first and a second terminal; M first wirings (M is an integer of 2 or more) extending in a first direction; and N second wirings (N is an integer of 2 or more) extending in a second direction intersecting the first direction and electrically connected to the M first wirings, respectively, a plurality of first terminal wirings electrically connected to the first terminals of the light emitting elements; a plurality of second terminal wirings electrically connected to the second terminals of the light emitting elements, each electrically connected to P (P is an integer of 2 or more) of the light emitting elements; a plurality of selection circuits respectively connected to one of the plurality of first terminal wirings and the plurality of second terminal wirings and selecting the corresponding light emitting elements; and a plurality of drive circuits respectively connected to the other of the plurality of first terminal wirings and the plurality of second terminal wirings and driving the corresponding light emitting elements. A distance measuring device is provided, which includes: a plurality of capacitors electrically connected to one of the first and second terminal wirings and storing electric charges for passing current through the plurality of light-emitting elements; a first substrate on which the plurality of light-emitting elements are arranged; and a second substrate stacked on the first substrate and on which the plurality of drive circuits are arranged, wherein the plurality of capacitors are arranged so that at least a portion of them overlap the first substrate and the second substrate when viewed in a plane.

[0027] 1. A circuit diagram of a light emitting device according to a first embodiment. A cross-sectional view showing an example of the cross-sectional structure of a light emitting device having a VCSEL structure. A waveform diagram of an output current from an LDD substrate to each light emitting element 23. A perspective view schematically showing the structure of a light emitting device 1a according to the first embodiment. A schematic perspective view showing a first example of a capacitor arrangement location. A schematic perspective view showing a second example of a capacitor arrangement location. A schematic perspective view showing a third example of a capacitor arrangement location. A schematic perspective view showing a fourth example of a capacitor arrangement location. A schematic perspective view of a light emitting device according to a comparative example. A circuit diagram of a light emitting device according to a modified example of the first embodiment shown in FIG. 1. A plan view of an LDD substrate in a light emitting device according to a second embodiment. A plan view of an LDD substrate provided in a light emitting device according to a comparative example. A circuit diagram of a light emitting device according to a third embodiment. A circuit diagram of a light emitting device according to a first modified example of the third embodiment. A circuit diagram of a light emitting device according to a second modified example of the third embodiment. A circuit diagram of a light emitting device according to a third modified example of the third embodiment. A block diagram showing an example of the configuration of a distance measuring device. An explanatory diagram of an STL system. The present invention relates to a vehicle control system, a vehicle exterior information detection unit, and an imaging unit.

[0028] Hereinafter, embodiments of a light emitting device and a distance measuring device will be described with reference to the drawings. The following description will focus on the main components of the light emitting device and the distance measuring device, but the light emitting device and the distance measuring device may include components and functions that are not shown or described. The following description does not exclude components and functions that are not shown or described.

[0029] (First Embodiment) Fig. 1 is a circuit diagram of a light emitting device 1 according to a first embodiment. As shown in Fig. 1, the light emitting device 1 according to the first embodiment includes a plurality of light emitting elements 23 arranged in a two-dimensional array, and a plurality of transistors 24 electrically connected to these light emitting elements 23. These transistors 24 are, for example, N-type MOS transistors. Fig. 1 shows an example in which the light emitting device 1 according to the first embodiment includes 9 x 9 light emitting elements 23 and 9 x 9 transistors 24. Therefore, the light emitting device 1 shown in Fig. 1 includes a 9ch (channel) x 9ch light emitting element array. The number of channels in the light emitting element array is arbitrary.

[0030] 1 , the light-emitting device 1 according to the first embodiment further includes a first anode wiring 31, a second anode wiring 32, a third anode wiring 33, a plurality of first capacitors 34, a plurality of second capacitors 35, a plurality of third capacitors 36, a first selection circuit 37, a second selection circuit 38, a third selection circuit 39, a plurality of cathode wirings 41, and a plurality of gate wirings 42. The first to third anode wirings 31 to 33 are an example of the first terminal wiring of the present disclosure, and the cathode wiring 41 is an example of the second terminal wiring of the present disclosure. The first to third capacitors 34 to 36 are an example of the first to M-th capacitors of the present disclosure, and the first to third selection circuits 37 to 39 are an example of the first to M-th selection circuits of the present disclosure (M is an integer of 2 or more). FIG. 1 shows an example in which M is 3.

[0031] The first terminal wirings include M first wirings (M is an integer of 2 or greater) 31a, 32a, and 33a extending in a first direction X, and N second wirings (N is an integer of 2 or greater) 31b, 32b, and 33b extending in a second direction Y intersecting the first direction X and electrically connected to the M first wirings 31a, 32a, and 33a, respectively. FIG. 1 shows an example where M=N=3. The first terminal wirings are electrically connected to first terminals of a plurality of light-emitting elements 23. In this specification, the first wirings 31a and the second wirings 31b connected to each other are referred to as first anode wirings 31, the second wirings 32a and 32b connected to each other are referred to as second anode wirings 32, and the third wirings 33a and 33b connected to each other are referred to as third anode wirings 33. In this specification, the first direction X may be referred to as the horizontal direction, and the second direction Y may be referred to as the vertical direction. In the following, the first terminal wiring and one of the plurality of second terminal wirings may be referred to as an anode wiring, and the other of the first terminal wiring and the plurality of second terminal wirings may be referred to as a cathode wiring.

[0032] The light emitting device 1 according to the first embodiment includes L (L is an integer of 1 or more) sets of first to third anode wirings 31 to 33. Figure 1 shows an example where L = 5.

[0033] The five sets of first anode wirings 31 include a plurality of (e.g., five) first wirings 31a each extending in the first direction X (horizontal direction) and arranged along the second direction Y (vertical direction), and a plurality of (e.g., five) second wirings 31b each extending in the second direction Y (vertical direction) and arranged along the first direction X (horizontal direction). In this specification, the first wirings 31a may be referred to as first horizontal wirings 31a, and the second wirings 31b may be referred to as first vertical wirings 31b.

[0034] The five sets of second anode wirings 32 each include a plurality of (e.g., five) first wirings 32a each extending in the first direction X (horizontal direction) and arranged along the second direction Y (vertical direction), and a plurality of (e.g., five) second wirings 32b each extending in the second direction Y (vertical direction) and arranged along the first direction X (horizontal direction). In this specification, the first wirings 32a may be referred to as second horizontal wirings 32a, and the second wirings 32b may be referred to as second vertical wirings 32b.

[0035] The five sets of third anode wirings 33 each include a plurality of (e.g., five) first wirings 33a each extending in the first direction X (horizontal direction) and arranged along the second direction Y (vertical direction), and a plurality of (e.g., five) second wirings 33b each extending in the second direction Y (vertical direction) and arranged along the first direction X (horizontal direction). In this specification, the first wirings 33a may be referred to as third horizontal wirings 33a, and the second wirings 33b may be referred to as third vertical wirings 33b.

[0036] 1 shows an example in which the light-emitting device 1 according to the first embodiment includes five first horizontal wires 31a, five first vertical wires 31b, five second horizontal wires 32a, five second vertical wires 32b, five third horizontal wires 33a, and five third vertical wires 33b. Fig. 1 also shows an example in which L sets of M first wires and N second wires are provided. The number of light-emitting elements 23 shown in Fig. 1 is M(L-2) x N(L-2), where L, M, and N are the numbers.

[0037] The first to third anode wirings 31 to 33 may include La sets of first to M-th horizontal wirings and Lb sets of first to N-th vertical wirings (La and Lb are integers of 2 or greater that satisfy La≠Lb). In this case, the number of light-emitting elements 23 in the light-emitting device 1 is M(La-2)×N(Lb-2).

[0038] The first selection circuit 37 includes transistors 37a and 37b connected in series. Similarly, the second selection circuit 38 includes transistors 38a and 38b connected in series. Similarly, the third selection circuit 39 includes transistors 39a and 39b connected in series. The transistors 37a, 38a, and 39a are, for example, P-type MOS transistors. The transistors 37b, 38b, and 39b are, for example, N-type MOS transistors. The transistors 37a, 38a, and 39a are examples of first switches of the present disclosure. The transistors 37b, 38b, and 39b are examples of second switches of the present disclosure.

[0039] [First to third anode wirings 31 to 33] In FIG. 1, in order to distinguish the first to third anode wirings 31 to 33 from one another, the first anode wiring 31 is shown by a thick solid line, the second anode wiring 32 is shown by a thick dashed line, and the third anode wiring 33 is shown by a thin solid line.

[0040] The first anode wiring 31 has a structure in which a plurality of first horizontal wirings 31a and a plurality of first vertical wirings 31b are arranged in a mesh pattern. These first horizontal wirings 31a and first vertical wirings 31b are electrically connected to each other at the locations where the first horizontal wirings 31a and first vertical wirings 31b intersect. Similarly, the second anode wiring 32 includes a plurality of second horizontal wirings 32a and a plurality of second vertical wirings 32b that are electrically connected to each other, and the third anode wiring 33 includes a plurality of third horizontal wirings 33a and a plurality of third vertical wirings 33b that are electrically connected to each other. Meanwhile, the first to third anode wirings 31 to 33 are electrically insulated from each other.

[0041] The first to third horizontal wirings 31a to 33a extend in the first direction X (horizontal direction) and are adjacent to each other in the second direction Y (vertical direction). Although the first to third horizontal wirings 31a to 33a extend linearly in the first direction X in FIG. 1, they may extend in a curved manner in the first direction X. That is, the first to third horizontal wirings 31a to 33a may include bent portions.

[0042] On the other hand, the first to third vertical wirings 31b to 33b extend in the second direction Y and are adjacent to each other in the first direction X. Although the first to third vertical wirings 31b to 33b extend linearly in the second direction Y in FIG. 1, they may also extend in a curved manner in the second direction Y. That is, the first to third vertical wirings 31b to 33b may also include bent portions.

[0043] FIG. 1 shows five sets of first to third horizontal wirings (first wirings) 31a to 33a. In FIG. 1, the first, second, third, fourth, and fifth sets of first to third horizontal wirings 31a to 33a are arranged in order from top to bottom. In each set, the first horizontal wiring 31a, the second horizontal wiring 32a, and the third horizontal wiring 33a are arranged in order from top to bottom. The first set of first to third horizontal wirings 31a to 33a and the fifth set of first to third horizontal wirings 31a to 33a are arranged so as to sandwich 9 × 9 light-emitting elements 23 therebetween. Each of the second to fourth sets of first to third horizontal wirings 31a to 33a is arranged along one row (nine light-emitting elements) 23.

[0044] FIG. 1 further shows five sets of first to third vertical wirings (second wirings) 31b to 33b. In FIG. 1, the first, second, third, fourth, and fifth sets of first to third vertical wirings 31b to 33b are arranged in order from left to right. In each set, the first vertical wiring 31b, the second vertical wiring 32b, and the third vertical wiring 33b are arranged in order from left to right. The first set of first to third vertical wirings 31b to 33b and the fifth set of first to third vertical wirings 31b to 33b are arranged so as to sandwich 9 × 9 light-emitting elements 23 therebetween. Each of the second to fourth sets of first to third vertical wirings 31b to 33b is arranged along one column (nine light-emitting elements) 23.

[0045] The anode of each light-emitting element 23 is electrically connected to one of the first to third vertical wirings 31b to 33b. For example, the light-emitting element 23 in the leftmost column is electrically connected to the first vertical wiring 31b in the second set of first to third vertical wirings 31b to 33b. The light-emitting element 23 in the rightmost column is electrically connected to the third vertical wiring 33b in the fourth set of first to third vertical wirings 31b to 33b. The anode of each light-emitting element 23 may be electrically connected to one of the first to third horizontal wirings 31a to 33a instead of being electrically connected to one of the first to third vertical wirings 31b to 33b. The anode is an example of a first terminal in the present disclosure.

[0046] [Cathode Wiring 41] Each cathode wiring 41 extends in the first direction X and is electrically connected to the cathodes of three light-emitting elements 23. Specifically, each cathode wiring 41 is electrically connected to one light-emitting element 23 electrically connected to the first vertical wiring 31b, one light-emitting element 23 electrically connected to the second vertical wiring 32b, and one light-emitting element 23 electrically connected to the third vertical wiring 33b. These three light-emitting elements 23 are adjacent to each other in the first direction X. FIG. 1 shows 27 cathode wirings 41 for 81 light-emitting elements 23. The cathodes are an example of the second terminals of the present disclosure. The number of light-emitting elements 23 connected to each cathode wiring 41 is not limited to three. Each cathode wiring 41 may be electrically connected to the cathodes of P light-emitting elements 23 (P is an integer greater than or equal to 2).

[0047] In the above description, an example has been described in which a plurality of light-emitting elements 23 are connected to first to M-th horizontal wires, first to N-th vertical wires, and a plurality of second terminal wires electrically connected in P units, but the light-emitting device according to the present disclosure does not need to include all of the first to M-th horizontal wires, first to N-th vertical wires, and a plurality of second terminal wires electrically connected in P units. For example, a configuration in which a plurality of light-emitting devices are connected to first to M-th horizontal wires, a single vertical wire, and a single second terminal wire may also be employed.

[0048] Each light-emitting element 23 is provided between a corresponding anode wiring, i.e., any one of the first to third anode wirings 31 to 33, and a corresponding cathode wiring, i.e., any one of the plurality of cathode wirings 41. Each light-emitting element 23 emits light when a current flows between the corresponding anode wiring and the corresponding cathode wiring.

[0049] [Gate Wiring 42] Each gate wiring 42 extends in the first direction X and is electrically connected to the gates of three transistors 24. The sources of these three transistors 24 are electrically connected to the ground wiring (GND), and the drains of these three transistors 24 are electrically connected to the same single cathode wiring 41. These three transistors 24 form one drive circuit E. FIG. 1 shows 27 gate wirings 42 for 81 transistors 24.

[0050] Each drive circuit E is electrically connected to the cathodes of three light-emitting elements 23 via one cathode wiring 41. Each drive circuit E (output stage) E is used to drive the light-emitting elements 23 to generate (output) light from the light-emitting elements 23. For example, to generate light from a certain light-emitting element 23, a predetermined signal is applied to the gate wiring 42 of the drive circuit E for that light-emitting element 23. This brings the source and drain of each transistor 24 in that drive circuit E into conduction, allowing current to flow through that light-emitting element 23. When current flows through that light-emitting element 23, light is generated from that light-emitting element 23. The light-emitting device 1 shown in FIG. 1 includes 27 drive circuits E for 81 light-emitting elements 23.

[0051] [First to Third Selection Circuits 37 to 39] The first to third selection circuits 37 to 39 are electrically connected to the first to third horizontal wirings 31a to 33a of the first to third anode wirings 31 to 33, respectively. The first selection circuit 37 is used to select the light-emitting element 23 electrically connected to the first anode wiring 31 as the light-emitting element 23 that generates light. The second selection circuit 38 is used to select the light-emitting element 23 electrically connected to the second anode wiring 32 as the light-emitting element 23 that generates light. The third selection circuit 39 is used to select the light-emitting element 23 electrically connected to the third anode wiring 33 as the light-emitting element 23 that generates light. The first to third selection circuits 37 to 39 may be electrically connected to the first to third vertical wirings 31b to 33b of the first to third anode wirings 31 to 33, respectively, instead of the first to third horizontal wirings 31a to 33a of the first to third anode wirings 31 to 33.

[0052] The first selection circuit 37 includes a transistor 37a having a source electrically connected to the power supply wiring (VDD) and a transistor 37b having a source electrically connected to the ground wiring. The drains of the transistors 37a and 37b are electrically connected to the first anode wiring 31. The first selection circuit 37 is electrically connected to each of the first capacitors 34 via the first anode wiring 31.

[0053] The transistor 37a is used to store charge in each first capacitor 34. The transistor 37b is used to discharge charge from each first capacitor 34. When a predetermined signal is applied to the gate of the transistor 37a, charge is stored in each first capacitor 34. When a predetermined signal is applied to the gate of the transistor 37b, charge is discharged from each first capacitor 34. Therefore, according to this embodiment, by selectively storing charge in the first capacitor 34 of the first to third capacitors 34 to 36 using the first selection circuit 37, it is possible to pass a current to each light-emitting element 23 electrically connected to the first anode wiring 31.

[0054] 1 , the second and third selection circuits 38, 39 have the same structure as the first selection circuit 37. Therefore, according to this embodiment, by storing charge in each second capacitor 35 by the second selection circuit 38, it is possible to pass a current to each light-emitting element 23 electrically connected to the second anode wiring 32. Furthermore, according to this embodiment, by storing charge in each third capacitor 36 by the third selection circuit 39, it is possible to pass a current to each light-emitting element 23 electrically connected to the third anode wiring 33.

[0055] [First to Third Capacitors 34 to 36] The first to third capacitors 34 to 36 are electrically connected to the first to third anode wirings 31 to 33, respectively. Each first capacitor 34 stores charge to be supplied to the light-emitting element 23 electrically connected to the first anode wiring 31. Each second capacitor 35 stores charge to be supplied to the light-emitting element 23 electrically connected to the second anode wiring 32. Each third capacitor 36 stores charge to be supplied to the light-emitting element 23 electrically connected to the third anode wiring 33. According to this embodiment, by supplying charge to each light-emitting element 23 from the first to third capacitors 34 to 36, a current can be passed through each light-emitting element 23. Each of the first to third capacitors 34 to 36 has one electrode electrically connected to one of the first to third anode wirings 31 to 33 and the other electrode electrically connected to a ground wiring.

[0056] The light-emitting device 1 shown in FIG. 1 includes a light-emitting element array including 9×9 light-emitting elements 23 arranged in a two-dimensional array. As shown in FIG. 1, the shape of this light-emitting element array is roughly square in plan view. The light-emitting device 1 shown in FIG. 1 includes four sets of first to third capacitors 34-36 near the four sides of the square. Specifically, the light-emitting device 1 shown in FIG. 1 includes a first set of first to third capacitors 34-36 near the top side of the square, a second set of first to third capacitors 34-36 near the right side of the square, a third set of first to third capacitors 34-36 near the bottom side of the square, and a fourth set of first to third capacitors 34-36 near the left side of the square. These first to third capacitors 34-36 are examples of K sets of first to Nth capacitors of the present disclosure (K is an integer greater than or equal to 2). FIG. 1 shows an example where K is 4.

[0057] The first to third capacitors 34 to 36 of the first and third sets are electrically connected to the first to third horizontal wirings 31 a to 33 a of the first to third anode wirings 31 to 33, respectively. On the other hand, the first to third capacitors 34 to 36 of the second and fourth sets are electrically connected to the first to third vertical wirings 31 b to 33 b of the first to third anode wirings 31 to 33, respectively. As a result, the first to third capacitors 34 to 36 shown in FIG. 1 are electrically connected to the first to third anode wirings 31 to 33, respectively.

[0058] In each set, the first to third capacitors 34 to 36 are arranged in clockwise order. For example, the first capacitor 34, the second capacitor 35, and the third capacitor 36 of the first set are respectively arranged on the left, center, and right sides near the top edge of the square. The first capacitor 34, the second capacitor 35, and the third capacitor 36 of the second set are respectively arranged on the upper, center, and lower sides near the right edge of the square. As a result, the four sets of first to third capacitors 34 to 36 shown in FIG. 1 are arranged symmetrically with respect to the center of the square. The center of the square is approximately located at the position of the light-emitting element 23 in the fifth row and fifth column of the 9×9 light-emitting elements 23. In FIG. 1, the four sets of first to third capacitors 34 to 36 are arranged in four-fold rotational symmetry (90-degree rotational symmetry).

[0059] According to this embodiment, it is possible to set the average distance between each light-emitting element 23 and the corresponding four capacitors to a value close to the average distance between another light-emitting element 23 and the corresponding four capacitors.

[0060] For example, the light-emitting element 23 at the upper left is close to the first capacitor 34 above but far from the first capacitor 34 below. On the other hand, the light-emitting element 23 at the lower right is close to the third capacitor 36 on the right but far from the third capacitor 36 on the left. Therefore, the average distance between the light-emitting element 23 at the upper left and the four first capacitors 34 is close to the average distance between the light-emitting element 23 at the lower right and the four third capacitors 36. This is also true for the other 79 light-emitting elements 23. This makes it possible to reduce the difference in impedance between the wiring of different light-emitting elements 23 with respect to the anode wiring between each light-emitting element 23 and the corresponding four capacitors.

[0061] The light emitting device 1 of this embodiment may include the first to third capacitors 34 to 36 only near one, two, or three of the four sides of the square. However, in this case, it is desirable that the first to third capacitors 34 to 36 are also arranged symmetrically or nearly symmetrically with respect to the center of the square. Therefore, it is desirable that the light emitting device 1 of this embodiment include the first to third capacitors 34 to 36 on two or more of the four sides of the square. For example, by arranging two sets of the first to third capacitors 34 to 36 near the top and bottom sides of the square, it is possible to achieve an arrangement with two-fold rotational symmetry (180-degree rotational symmetry).

[0062] Fig. 2 is a cross-sectional view showing an example of the cross-sectional structure of a light emitting device 1 with a VCSEL structure. The light emitting device 1 in Fig. 2 is configured, for example, by stacking an LD (Laser Diode) chip 11 on an LDD substrate 12. The LD chip 11 includes a substrate 21, a stacked film 22, a plurality of light emitting elements 23 formed using the stacked film 22, a plurality of anode electrodes 47, and a cathode electrode 48.

[0063] The substrate 21 of the LD chip 11 is made of a compound semiconductor such as GaAs (gallium arsenide). The surface of the substrate 21 facing the LDD substrate 12 is the front surface S2, and laser light is emitted from the back surface S3 of the substrate 21. The stacked film 22 includes a first multilayer reflector, a first spacer layer, an active layer, a second spacer layer, and a second multilayer reflector. The laser light generated in the active layer is resonated between the first multilayer reflector and the second multilayer reflector to increase the light intensity and is emitted from the back surface S3 of the substrate. Thus, the LD chip 11 of FIG. 2 is a back-illuminated type. In this specification, a light-emitting element 23 having the layer structure shown in FIG. 2 is referred to as a VCSEL structure.

[0064] The plurality of light-emitting elements 23 have a mesa structure formed by processing the laminated film 22 into a mesa shape. As viewed from the substrate 21 side, an anode electrode (second pad) 47 is disposed on the upper surface of each light-emitting element 23. Similarly, as viewed from the substrate 21 side, a cathode electrode 48 is disposed on the upper and side surfaces of the laminated film 22 disposed on the end side of the LD chip 11. As viewed from the substrate 21 side, a cathode electrode 48 is also disposed on the lowermost layer of the laminated film 22 of the plurality of light-emitting elements 23. In FIG. 2 , the anode electrode 47 and the cathode electrode 48 may be reversed. Although the common electrode in FIG. 2 is the cathode electrode 48, the common electrode may be the anode electrode 47, and a cathode electrode 48 may be provided on each mesa portion 20.

[0065] The LDD substrate 12 has a plurality of pads 49 for supplying drive signals to the plurality of light emitting elements 23 of the LD chip 11. The pads 49 are arranged along a surface S1 of the LDD substrate 12 that faces the LD chip 11. A bonding layer 50 is arranged on these pads 49, and the pads 49 of the LDD substrate 12 are bonded to the corresponding pads of the anode electrode 47 of the LD chip 11 via the bonding layer 50. The LDD substrate 12 has a plurality of drive circuits E shown in FIG.

[0066] The substrate 21 of the LD chip 11 is, for example, a compound semiconductor substrate such as a GaAs (gallium arsenide) substrate. Fig. 2 shows a front surface S2 of the substrate 21 facing the -Z direction and a back surface S3 of the substrate 21 facing the +Z direction. The front surface S2 and back surface S3 shown in Fig. 2 are perpendicular to the Z direction. In Fig. 2, the front surface S2 is the lower surface of the substrate 21, and the back surface S3 is the upper surface of the substrate 21.

[0067] The light emitting element 23 is provided on the surface S2 of the substrate 21 as part of the laminated film 22. The light emitting element 23 of this embodiment has a VCSEL structure and emits light in the +Z direction. As shown in FIG. 2 , the light emitted from the light emitting element 23 passes through the substrate 21 from the surface S2 to the back surface S3 of the substrate 21.

[0068] Each light-emitting element 23 is provided between an anode electrode 47 and a cathode electrode 48 connected to the anode wirings 31 to 33. Each light-emitting element 23 emits light when a current flows between the anode electrode 47 and the cathode electrode 48.

[0069] 3 is a waveform diagram of the output current from the LDD substrate 12 to each light-emitting element 23. The vertical axis of FIG. 3 represents the LDD output current flowing from the LDD substrate 12 to each light-emitting element 23, and the horizontal axis represents time. FIG. 3 shows the waveform of the LDD output current. FIG. 3 also shows the peak value Ipeak of the LDD output current, the pulse width W of the LDD output current, and the half-value width W' of the LDD output current.

[0070] In order to improve the performance of the distance measuring device 40, it is desirable to increase the peak value Ipeak of the current flowing through each light-emitting element and shorten the pulse width W (or half-value width W'). Increasing the peak value of the current flowing through each light-emitting element and shortening the pulse enables high-accuracy distance measurement over long distances.

[0071] The upper limit of the peak value of the LDD output current is determined by safety standards for laser light. When multiple light-emitting elements are driven simultaneously by the LDD output current, the peak value of the current flowing through each light-emitting element decreases. For this reason, in this embodiment, each light-emitting element is driven individually. When each light-emitting element is driven individually, the peak value of the current flowing through each light-emitting element is several tens of amperes, and a high-power, short pulse with a pulse width on the order of several nanoseconds is required. To meet this requirement, it is necessary to reduce parasitic inductance and minimize variations between channels. The light-emitting device configured as shown in FIG. 1 performs split passive matrix driving, which can meet the above requirements.

[0072] FIG. 4 is a perspective view schematically illustrating the structure of the light-emitting device 1 of the first embodiment. FIG. 4 also illustrates the structure of the wiring layer disposed on the surface of the LD chip 11 facing the LDD substrate 12. As shown in FIG. 4 , the wiring layer has a laminated structure, with a first wiring layer M1, a second wiring layer M2, and a third wiring layer M3 laminated in this order from the farthest side from the LDD substrate 12. The first wiring layer M1 includes the first horizontal wiring 31a and the first vertical wiring 31b of the first anode wiring 31. The second wiring layer M2 includes the first horizontal wiring 32a and the first vertical wiring 32b of the second anode wiring 32. The third wiring layer M3 includes the first horizontal wiring 33a and the first vertical wiring 33b of the third anode wiring 33.

[0073] 5 is a schematic perspective view showing a first example of the placement of the capacitors 34 to 36. In this first example, the capacitors 34 to 36 are stacked on or above the third wiring layer M3 of the LD chip 11. The capacitors 34 to 36 are arranged side by side in the planar direction. The capacitors 34 to 36 are electrically connected to the first to third anode wirings 31 to 33, for example, by vias.

[0074] 5, the capacitors 34 to 36 are arranged on or above the third wiring layer M3 of the LD chip 11, so that the capacitors 34 to 36 can be arranged to overlap the LD chip 11 in plan view, thereby reducing the size of the light-emitting device 1. The capacitors 34 to 36 are arranged on the third wiring layer M3 of the LD chip 11, so that the distances between each of the capacitors 34 to 36 and the selection circuits 37 to 39 can be made uniform, and the distances between the capacitors 34 to 36 and the light-emitting element 23 can be made uniform.

[0075] FIG. 6 is a schematic perspective view showing a second example of the placement of the capacitors 34-36. In this second example, multiple capacitors 34-36 are arranged in the planar direction on the side of the LDD substrate 12 facing the LD chip 11. The capacitors 34-36 are electrically connected to the first to third anode wirings 31-33 arranged on the wiring layer of the LD chip 11, for example, via CCCs (copper-to-copper connections). In FIG. 6, the capacitors 34-36 are arranged on a layer separate from the layer on which the drive circuit E of the LDD substrate 12 is arranged. For example, the capacitors 34-36 are arranged on the wiring layer of the LDD substrate 12.

[0076] 6, the capacitors 34 to 36 are arranged on the LDD substrate 12, so that the capacitors 34 to 36 are not arranged outside the LD chip 11 in plan view, thereby enabling the miniaturization of the light emitting device 1. Furthermore, in the second example, the capacitors 34 to 36 are arranged on the LDD substrate 12, so that the distance between the capacitors 34 to 36 and the light emitting element 23 can be shortened, and it is also easy to make the distance between the capacitors 34 to 36 and the light emitting element 23 uniform.

[0077] FIG. 7 is a schematic perspective view showing a third example of the placement of the capacitors 34-36. In this third example, a substrate 18 on which the capacitors 34-36 are placed (hereinafter referred to as the substrate on which the capacitors 34-36 are placed) is stacked between the LD chip 11 and the LDD substrate 12. The substrate 18 on which the capacitors 34-36 are placed is, for example, a silicon substrate on which the capacitors 34-36 are placed, and is fabricated in advance. The substrate 18 on which the capacitors 34-36 are placed has the same external dimensions as the LD chip 11 and the LDD substrate 12. This prevents the capacitors 34-36 from being positioned outside the LD chip 11 and the LDD substrate 12 in a planar view, thereby enabling the light-emitting device 1 to be miniaturized. The capacitors 34-36 placed on the substrate 18 are electrically connected to the first to third anode wirings 31-33, for example, via CCCs and vias. Furthermore, the capacitors 34 to 36 arranged on the substrate 18 and the selection circuits 37 to 39 on the LDD substrate 12 are electrically connected via, for example, CCCs and vias.

[0078] FIG. 8 is a schematic perspective view showing a fourth example of the placement of the capacitors 34-36. In this fourth example, the capacitors 34-36 are placed on the surface of the LDD substrate 12 opposite the surface facing the LD chip 11 (hereinafter referred to as the back surface). The capacitors 34-36 may be placed directly on the back surface of the LDD substrate 12, or a substrate 18 on which the capacitors 34-36 are placed, which is provided separately from the LDD substrate 12, may be stacked on the LDD substrate 12. In the fourth example, the capacitors 34-36 are not placed outside the LD chip 11 and the LDD substrate 12 in a plan view, thereby enabling the light-emitting device to be miniaturized. The capacitors 34-36 and the first to third anode wirings 31-33 of the LD chip 11 are electrically connected via through-silicon vias (TSVs) that penetrate the LDD substrate 12.

[0079] 5 to 8 described above show an example in which the plurality of capacitors 34 to 36 are arranged so as to overlap the LD chip 11 and the LDD substrate 12 in a planar view, but some of the plurality of capacitors 34 to 36 may be arranged outside the LD chip 11 and the LDD substrate 12 in a planar view. Thus, in the first embodiment, it is sufficient that at least some of the plurality of capacitors 34 to 36 are arranged so as to overlap the LD chip 11 and the LDD substrate 12 in a planar view.

[0080] The capacitors 34 to 36 shown in FIGS. 5 to 8 are capacitors having a metal-insulator-metal (MIM) structure, a metal-oxide-metal (MOM) structure, a trench structure, or wiring capacitance.

[0081] FIG. 9 is a schematic perspective view of a light-emitting device 100 according to a comparative example. Like the light-emitting devices according to the first to fourth examples, the light-emitting device 100 according to the comparative example has a circuit configuration similar to that shown in FIG. 1. In the light-emitting device according to the comparative example, as shown in FIG. 9, the capacitors 34-36 are evenly arranged around the periphery of the LDD substrate 12. This increases the wiring length of the first to third anode wirings 31-33 extending from the LD chip 11 to the respective capacitors 34-36, resulting in greater variation in the wiring length and wiring capacitance for each capacitor 34-36. Furthermore, this also increases variation in the wiring length and wiring capacitance from each capacitor 34-36 to the selection circuits 37-39 on the LDD substrate 12. This results in fluctuations in the peak value, pulse width, or light-emission timing of the light-emitting pulse waveform of each light-emitting element 23. Furthermore, since the capacitors 34-36 are arranged outside the LDD substrate 12, it becomes difficult to miniaturize the light-emitting device. In the light-emitting devices according to the first to fourth examples, as described above, the capacitors 34 to 36 are arranged between the LD chip 11 and the LDD substrate 12 or on the back side of the LDD substrate 12, which makes it possible to reduce the size of the light-emitting device, shorten the wiring length of the capacitors 34 to 36, and suppress variations in the wiring length, thereby suppressing fluctuations in the light-emitting pulse waveform.

[0082] Fig. 10 is a circuit diagram of a light-emitting device 1a according to a modification of the first embodiment shown in Fig. 1. The light-emitting device 1a according to this modification is characterized in that, for each of the capacitors 34 to 36, a switch (capacitance selector) 19 can be used to switch between two of the capacitors 34 to 36, each having a different capacitance. Therefore, twice as many capacitors 34 to 36 and switchers 19 are required as compared to Fig. 1. These capacitors 34 to 36 and switchers 19 are arranged between the LD chip 11 and the LDD substrate 12 or on the back side of the LDD substrate 12, as in any of the first to fourth examples described above.

[0083] According to one modification, the peak value and pulse width of the light emission pulse waveform can be easily variably controlled because the capacitance of each of the capacitors 34 to 36 can be switched by the switch 19. Note that the switch 19 may switch between three or more capacitors 34 to 36 each having a different capacitance.

[0084] As described above, in the first embodiment, at least some of the capacitors 34 to 36 connected to the first to third anode wirings 31 to 33 are arranged to overlap the LD chip 11 and the LDD substrate 12 in a plan view, thereby making it possible to reduce the size of the light emitting device 1. Furthermore, by arranging the capacitors 34 to 36 between the LD chip 11 and the LDD substrate 12 or on the back surface side of the LDD substrate 12, the wiring lengths of the first to third anode wirings 31 to 33 can be shortened and variations in wiring lengths can be suppressed, thereby suppressing variations in the peak value, pulse width, and light emission timing of the light emission pulse waveform.

[0085] Second Embodiment A light emitting device according to a second embodiment is characterized in that a power supply IC that determines the anode voltage of the light emitting element 23 is mounted on the LDD substrate 12 .

[0086] The light emitting device according to the second embodiment is configured by stacking an LD chip 11 and an LDD substrate 12, similar to Fig. 2. The light emitting device according to the second embodiment also has a circuit configuration similar to that shown in Fig. 1 or 10, for example.

[0087] The LD chip 11 has a plurality of light-emitting elements 23 arranged two-dimensionally. First to third anode wirings 31 to 33 are connected to the anodes of the plurality of light-emitting elements 23. A plurality of capacitors 34 to 36 are connected to the first to third anode wirings 31 to 33. Furthermore, first to third selection circuits 37 to 39 are connected to the first to third anode wirings 31 to 33. A power supply voltage is applied to the sources of transistors 37 a, 38 a, and 39 a in the first to third selection circuits 37 to 39. This power supply voltage determines the voltages across the plurality of capacitors 34 to 36 and the anode voltages of the plurality of light-emitting elements 23. The higher the anode voltages of the plurality of light-emitting elements 23, the larger the peak value of the light-emitting pulse waveform and the higher the light-emitting intensity.

[0088] The second embodiment is characterized by variably controlling the power supply voltage applied to the sources of transistors 37 a, 38 a, and 39 a of first to third selection circuits 37 to 39. The power supply voltage, the voltage level of which can be variably controlled, is generated by, for example, a power supply IC. Normally, the power supply IC is mounted on a substrate separate from the LDD substrate 12, but the second embodiment is characterized by the fact that the LDD substrate 12 has a built-in power supply circuit, eliminating the need for a power supply IC.

[0089] FIG. 11 is a plan view of the LDD substrate 12 in the light-emitting device 1 according to the second embodiment. The LDD substrate 12 according to the second embodiment includes a light-emitting section 2 having a VCSEL structure with a plurality of light-emitting elements 23, and a power supply circuit 4. The light-emitting section 2 having a VCSEL structure includes a plurality of light-emitting elements 23, for example, as shown in FIG. 1 or FIG. 10. The power supply circuit 4 can variably control the voltage level of the power supply voltage applied to the sources of the transistors 37 a, 38 a, and 39 a of the first to third selection circuits 37 to 39. This allows the power supply circuit 4 to adjust the voltage level of the power supply voltage (reference voltage) used to store charge in the plurality of capacitors 34 to 36.

[0090] The power supply circuit 4 may adjust the voltage level of the power supply voltage based on a predetermined control signal. The control signal may be a signal that controls at least one of the peak value, pulse width, or light emission timing of the light emission pulse waveform of the plurality of light-emitting elements 23. Alternatively, the control signal may be a signal that compensates for the ambient temperature of the plurality of light-emitting elements 23. Alternatively, the control signal may be a signal that controls the light emission output of the plurality of light-emitting elements according to the distance to an object. The control signal may be a signal generated by the light-emitting device 1 or a signal generated by a distance measuring device.

[0091] The power supply circuit 4 may also variably control the voltage level of the power supply voltage based on a control signal transmitted from a host device (not shown), for example. The host device adjusts the voltage level of the power supply voltage in accordance with the light-emitting characteristics of the plurality of light-emitting elements 23.

[0092] The power supply voltage generated by the power supply circuit 4 may be used not only as the power supply voltage for the first to third selection circuits 37 to 39, but also as the power supply voltage for circuits other than the first to third selection circuits 37 to 39 arranged on the LDD substrate 12.

[0093] 12 is a plan view of an LDD substrate 12 included in a light emitting device 1 according to a comparative example. The LDD substrate 12 according to the comparative example has a VCSEL but does not have a power supply circuit 4. The light emitting device 1 according to the comparative example includes a power supply IC 4a separate from the LDD substrate 12. The power supply IC 4a is mounted on a substrate separate from the LDD substrate 12.

[0094] The power supply IC 4a generates a power supply voltage and supplies it to the LDD substrate 12. The LDD substrate 12 applies the power voltage generated by the power supply IC 4a to the sources of the transistors 37a, 38a, and 39a of the first to third selection circuits 37-39.

[0095] As described above, in the second embodiment, the power supply circuit 4 is built into the LDD substrate 12, which allows the light emitting device 1 to be more compact and reduces component costs than if the power supply IC 4a were provided separately from the LDD substrate 12. Furthermore, in this embodiment, the voltage level of the power supply voltage generated by the power supply circuit 4 is controlled to match the light emission characteristics of the plurality of light emitting elements 23, for example, so that the light emission characteristics of the plurality of light emitting elements 23 can be optimized and distance measurement accuracy can be improved. Furthermore, in this embodiment, the voltage level of the power supply voltage can be adjusted according to temperature, allowing the temperature dependency of the light emitting device 1 to be accurately corrected.

[0096] Third Embodiment The light emitting device 1 according to the first and second embodiments is not necessarily limited to the circuit configuration shown in FIG. 1 or FIG.

[0097] FIG. 13 is a circuit diagram of a light-emitting device 1b according to a third embodiment. As shown in FIG. 13, the light-emitting device 1b according to the third embodiment includes first to third cathode wirings 31′ to 33′ in the positions of the first to third anode wirings 31 to 33 shown in FIG. 1, includes multiple anode wirings 41′ in the positions of the multiple cathode wirings 41, and omits the multiple gate wirings 42. Similarly to the first to third anode wirings 31 to 33, the first to third cathode wirings 31′ to 33′ each include first to third horizontal wirings 31a′ to 33a′ and first to third vertical wirings 31b′ to 33b′. The first to third cathode wirings 31′ to 33′ are an example of the first terminal wiring of the present disclosure. The anode wiring 41′ is an example of the second terminal wiring of the present disclosure.

[0098] Each light-emitting element 23 according to the third embodiment includes a cathode electrically connected to one of the first to third cathode wirings 31′ to 33′, and an anode electrically connected to one of the plurality of anode wirings 41′.

[0099] The light-emitting device 1b according to the third embodiment further includes first to third transistors 61 to 63 at the positions of the first to third capacitors 34 to 36 shown in FIG. 1 . The first to third transistors 61 to 63 are, for example, N-type MOS transistors. The gates of the first to third transistors 61 to 63 are electrically connected to the first to third gate wirings 64 to 66, respectively. Each of the first to third transistors 61 to 63 has a drain electrically connected to one of the first to third cathode wirings 31′ to 33′ and a source electrically connected to a ground wiring. Each of the first to third transistors 61 to 63 constitutes a drive circuit E. The drive circuits E including the first to third transistors 61 to 63 are examples of the first to Nth drive circuits, respectively.

[0100] The light emitting device 1b according to the third embodiment further includes a plurality of capacitors 67 at the positions of the plurality of transistors 24 shown in Fig. 1. Each of these capacitors 67 has one electrode electrically connected to one of the plurality of anode wirings 41' and the other electrode electrically connected to a ground wiring.

[0101] The light emitting device 1b according to the third embodiment further includes a plurality of selection circuits 68 instead of the first to third selection circuits 37 to 39. Each selection circuit 68 is electrically connected to a corresponding anode wiring 41′. Each selection circuit 68 includes a transistor 68a having a source electrically connected to a power supply wiring and a transistor 68b having a source electrically connected to a ground wiring. The drains of the transistors 68a and 68b are electrically connected to the cathode wiring 41. Each selection circuit 68 is electrically connected to a corresponding capacitor 67 via the anode wiring 41′. The transistor 68a is, for example, a P-type MOS transistor. The transistor 68b is, for example, an N-type MOS transistor. The transistor 68a is an example of a first switch of the present disclosure. The transistor 68b is an example of a second switch of the present disclosure.

[0102] The functions of the capacitor 67, transistor 68a, and transistor 68b are similar to those of the first to third capacitors 34 to 36, transistors 37a to 39a, and transistors 37b to 39b, respectively. Therefore, the capacitor 67 can be placed in the same location as the capacitors 34 to 36 in FIGS. 5 to 7. The transistor 68a can store charge in the corresponding capacitor 67. The transistor 68b can discharge charge from the corresponding capacitor 67. The capacitor 67 can supply charge to the light-emitting element 23 via the anode wiring 41′, thereby causing a current to flow through the light-emitting element 23.

[0103] The functions of the first to third transistors 61 to 63 and their drive circuit E are similar to those of the transistor 24 and its drive circuit E. The first to third transistors 61 to 63 can drive the light-emitting elements 23 electrically connected to the first to third cathode wirings 31′ to 33′, respectively.

[0104] According to the light emitting device 1b of the third embodiment, it is possible to realize the same control as that of the light emitting device 1 of the first embodiment, despite having a different structure from that of the light emitting device 1 of the first embodiment.

[0105] FIG. 14 is a circuit diagram of a light-emitting device 1c according to a first modification of the third embodiment. As shown in FIG. 14, the light-emitting device 1c according to the first modification includes first to third cathode wirings 31′ to 33′ at the positions of the first to third anode wirings 31 to 33 shown in FIG. 1, a plurality of anode wirings 41′ at the positions of the plurality of cathode wirings 41, and a plurality of gate wirings 42′ at the positions of the plurality of gate wirings 42. Furthermore, the first to third cathode wirings 31′ to 33′ each include first to third horizontal wirings 31a′ to 33a′ and first to third vertical wirings 31b′ to 33b′, respectively, similar to the first to third anode wirings 31 to 33. The first to third cathode wirings 31′ to 33′ are an example of the first terminal wiring of the present disclosure. The anode wiring 41′ is an example of the second terminal wiring of the present disclosure.

[0106] Each light-emitting element 23 in the first modification includes a cathode electrically connected to one of the first to third cathode wirings 31' to 33' and an anode electrically connected to one of the plurality of anode wirings 41'. Each transistor 24 in the first modification includes a gate electrically connected to one of the plurality of gate wirings 42', a drain electrically connected to one of the plurality of anode wirings 41', and a source electrically connected to a power supply wiring. Each transistor 24 in the first modification is, for example, a P-type MOS transistor. The first to third capacitors 34 to 36 and the first to third selection circuits 37 to 39 in the first modification are electrically connected to the first to third cathode wirings 31' to 33', respectively.

[0107] According to the light emitting device 1c of the first modification, it is possible to realize the same control as that of the light emitting device 1 of the first embodiment, despite having a different structure from that of the light emitting device 1 of the first embodiment.

[0108] FIG. 15 is a circuit diagram of a light-emitting device 1d according to a second modification of the third embodiment. As shown in FIG. 15, the light-emitting device 1d according to the second modification includes six sets of first to third capacitors 34 to 36 instead of the four sets of first to third capacitors 34 to 36 shown in FIG. 1. The first to third capacitors 34 to 36 of the second modification are disposed within the LD chip 11, within the LDD substrate 12, between the LD chip 11 and the LDD substrate 12, or on the back side of the LDD substrate 12, as in FIGS. 5 to 7 , and therefore can be disposed near the light-emitting element 23. In the second modification, each first capacitor 34 is electrically connected to one of the horizontal wirings 31a, each second capacitor 35 is electrically connected to one of the horizontal wirings 32a, and each third capacitor 36 is electrically connected to one of the horizontal wirings 33a.

[0109] According to the light emitting device 1d of the second modification, it is possible to realize the same control as that of the light emitting device 1 of the first embodiment, despite having a different structure from that of the light emitting device 1 of the first embodiment.

[0110] 16 is a circuit diagram of a light-emitting device 1e according to a third modification of the third embodiment. The light-emitting device 1e according to the third modification includes first to third voltage detection circuits 71 to 73 in addition to the components shown in FIG. 1. The first voltage detection circuit 71 is electrically connected to the first horizontal wiring 31a of the first anode wiring 31 and the gate of the transistor 37a. The second voltage detection circuit 72 is electrically connected to the second horizontal wiring 32a of the second anode wiring 32 and the gate of the transistor 38a. The third voltage detection circuit 73 is electrically connected to the third horizontal wiring 33a of the third anode wiring 33 and the gate of the transistor 39a.

[0111] The first voltage detection circuit 71 detects the voltage of the first anode wiring 31 from the first horizontal wiring 31a of the first anode wiring 31. This voltage indicates the amount of charge stored in the four first capacitors 34. Therefore, the first voltage detection circuit 71 controls the gate voltage of the transistor 37a based on the voltage detected from the first anode wiring 31. For example, if the detected voltage is lower than a predetermined voltage, the transistor 37a is turned on to start storing charge. On the other hand, if the detected voltage is higher than the predetermined voltage, the transistor 37a is turned off to end storing charge. According to the third modification, the output power of the light-emitting device 1e can be changed by changing the value of this predetermined voltage. The value of this predetermined voltage is adjusted, for example, by the control unit 9 shown in FIG. 1.

[0112] Similarly, the second voltage detection circuit 72 detects the voltage of the second anode wiring 32 and controls the gate voltage of the transistor 38 a based on the detected voltage. The third voltage detection circuit 73 detects the voltage of the third anode wiring 33 and controls the gate voltage of the transistor 39 a based on the detected voltage.

[0113] (Configuration of Distance Measuring Device 40) FIG. 17 is a block diagram showing an example of the configuration of a distance measuring device 40 as an example of implementation of the light emitting device 1 according to this embodiment.

[0114] As shown in the figure, the distance measuring device 40 includes a light emitting unit 2, a driving unit 3, a power supply circuit 4, a light emitting side optical system 5, a light receiving side optical system 6, a light receiving unit 7, a signal processing unit 8, a control unit 9, and a temperature detection unit 10.

[0115] The light-emitting unit 2 emits light from a plurality of light sources. The light-emitting unit 2 and the light-emitting side optical system 5 correspond to the above-described light-emitting device 1. As will be described later, the light-emitting unit 2 in this example has light-emitting elements 23, each of which is a vertical cavity surface-emitting laser (VCSEL), as its light source, and these light-emitting elements 23 are arranged in a predetermined pattern, such as a matrix.

[0116] The driver 3 includes a power supply circuit 4 for driving the light-emitting unit 2. The power supply circuit 4 generates a power supply voltage (a driving voltage Vd, which will be described later) for the driver 3 based on an input voltage (an input voltage Vin, which will be described later) from, for example, a battery (not shown) or the like provided in the distance measuring device 40. The driver 3 drives the light-emitting unit 2 based on the power supply voltage.

[0117] Light emitted from the light-emitting unit 2 is irradiated onto a subject (object) S, which is the object of distance measurement, via a light-emitting optical system 5. The light thus irradiated is reflected from the subject S and enters the light-receiving surface of the light-receiving unit 7 via a light-receiving optical system 6.

[0118] The light receiving unit 7 has a light receiving element such as a CCD (Charge Coupled Device) sensor or a CMOS (Complementary Metal Oxide Semiconductor) sensor, receives reflected light from the subject S that enters via the light receiving side optical system 6 as described above, converts the light into an electrical signal, and outputs the electrical signal. The light receiving unit 7 and the light receiving side optical system 6 constitute a light receiving device.

[0119] The light receiving unit 7 performs processes such as CDS (Correlated Double Sampling) and AGC (Automatic Gain Control) on the electrical signal obtained by photoelectrically converting the received light, and then performs A / D (Analog / Digital) conversion on the electrical signal, and outputs the resulting digital data to the signal processing unit 8 at the downstream side.

[0120] Furthermore, the light receiving unit 7 in this example outputs a frame synchronization signal Fs to the driving unit 3. This enables the driving unit 3 to cause the light emitting element 23 in the light emitting unit 2 to emit light at a timing according to the frame period of the light receiving unit 7.

[0121] The signal processing unit 8 has a signal processor such as a DSP (Digital Signal Processor), etc. The signal processing unit 8 performs various signal processes on the digital signal input from the light receiving unit 7.

[0122] The control unit 9 has, for example, a microcomputer having a CPU (Central Processing Unit), ROM (Read Only Memory), RAM (Random Access Memory), etc., or an information processing device such as a DSP, and controls the drive unit 3 for controlling the light emission operation by the light emitting unit 2, and controls the light receiving operation by the light receiving unit 7.

[0123] The control unit 9 has a function as a distance measuring unit 9a. The distance measuring unit 9a measures the distance to the subject S based on a signal input via the signal processing unit 8 (i.e., a signal obtained by receiving reflected light from the subject S). The distance measuring unit 9a in this example measures the distance to each part of the subject S in order to be able to identify the three-dimensional shape of the subject S.

[0124] The specific distance measurement method used by the distance measuring device 40 will be explained later.

[0125] The temperature detection unit 10 detects the temperature of the light emitting unit 2. The temperature detection unit 10 performs temperature detection using, for example, a diode.

[0126] In this example, information about the temperature detected by the temperature detection unit 10 is supplied to the drive unit 3, which enables the drive unit 3 to drive the light emitting unit 2 based on the temperature information.

[0127] (Range Measurement Method) The distance measurement method used in the distance measurement device 40 may be, for example, a STL (Structured Light) method or a ToF (Time of Flight) method.

[0128] The STL method is a method for measuring distance based on an image of a subject S illuminated with light having a predetermined light / dark pattern, such as a dot pattern or a grid pattern.

[0129] Fig. 18A is an explanatory diagram of the STL method. In the STL method, pattern light Lp having a dot pattern such as that shown in Fig. 18A is irradiated onto a subject S. The pattern light Lp is divided into a plurality of blocks BL, and a different dot pattern is assigned to each block BL (dot patterns are arranged not to overlap between blocks BL).

[0130] FIG. 18B is an explanatory diagram of the distance measurement principle of the STL system.

[0131] In this example, a wall W and a box BX placed in front of it are treated as the subject S, and pattern light Lp is irradiated onto the subject S. "G" in the figure schematically represents the angle of view of the light receiving unit 7.

[0132] In addition, in the drawing, "BLn" denotes the light of a certain block BL in the pattern light Lp, and "dn" denotes the dot pattern of the block BLn projected on the light-receiving image by the light-receiving unit 7.

[0133] Here, if there is no box BX in front of the wall W, the dot pattern of the block BLn is projected at the position "dn'" in the figure in the received light image. In other words, the position at which the pattern of the block BLn is projected in the received light image differs depending on whether the box BX is present or not, and specifically, the pattern is distorted.

[0134] The STL method utilizes the fact that the irradiated pattern is distorted by the object shape of the subject S to determine the shape and depth of the subject S. Specifically, this method determines the shape and depth of the subject S from the way the pattern is distorted.

[0135] When the STL system is adopted, for example, a global shutter type IR (Infrared) light receiving unit 7 is used as the light receiving unit 7. In the case of the STL system, the distance measuring unit 9a controls the drive unit 3 so that the light emitting unit 2 emits pattern light, detects distortion of the pattern in the image signal obtained via the signal processing unit 8, and calculates the distance based on the distortion of the pattern.

[0136] Next, the ToF method is a method for measuring the distance to an object by detecting the time of flight (time difference) of light emitted from the light-emitting unit 2, reflected by the object, and reaching the light-receiving unit 7.

[0137] When the so-called direct ToF (dTOF) method is adopted as the ToF method, a SPAD (Single Photon Avalanche Diode) is used as the light receiving unit 7, and the light emitting unit 2 is pulse-driven. In this case, the distance measuring unit 9a calculates the time difference between light emission and reception of light emitted from the light emitting unit 2 and received by the light receiving unit 7 based on a signal input via the signal processing unit 8, and calculates the distance to each part of the subject S based on the time difference and the speed of light.

[0138] When the so-called indirect ToF (iTOF) method (phase difference method) is adopted as the ToF method, the light receiving unit 7 used is, for example, a light receiving unit 7 capable of receiving IR.

[0139] <<Application Examples>> The technology according to the present disclosure can be applied to various products. For example, the technology according to the present disclosure may be realized as a device mounted on any type of moving body, such as an automobile, an electric vehicle, a hybrid electric vehicle, a motorcycle, a bicycle, personal mobility, an airplane, a drone, a ship, a robot, construction machinery, or agricultural machinery (tractor).

[0140] 19 is a block diagram showing a schematic configuration example of a vehicle control system 7000, which is an example of a mobile object control system to which the technology according to the present disclosure can be applied. The vehicle control system 7000 includes a plurality of electronic control units connected via a communication network 7010. In the example shown in FIG. 19 , the vehicle control system 7000 includes a drive system control unit 7100, a body system control unit 7200, a battery control unit 7300, an outside-vehicle information detection unit 7400, an inside-vehicle information detection unit 7500, and an integrated control unit 7600. The communication network 7010 connecting these multiple control units may be an in-vehicle communication network conforming to any standard, such as a Controller Area Network (CAN), a Local Interconnect Network (LIN), a Local Area Network (LAN), or FlexRay (registered trademark).

[0141] Each control unit includes a microcomputer that performs arithmetic processing according to various programs, a memory unit that stores the programs executed by the microcomputer or parameters used in various calculations, and a drive circuit that drives various controlled devices. Each control unit includes a network I / F for communicating with other control units via a communication network 7010, and a communication I / F for communicating with devices or sensors inside and outside the vehicle via wired or wireless communication. Figure 19 illustrates the functional configuration of the integrated control unit 7600, including a microcomputer 7610, a general-purpose communication I / F 7620, a dedicated communication I / F 7630, a positioning unit 7640, a beacon receiving unit 7650, an in-vehicle device I / F 7660, an audio / video output unit 7670, an in-vehicle network I / F 7680, and a memory unit 7690. The other control units also include a microcomputer, a communication I / F, a memory unit, and the like.

[0142] The drivetrain control unit 7100 controls the operation of devices related to the drivetrain of the vehicle in accordance with various programs. For example, the drivetrain control unit 7100 functions as a control device for a drive force generating device for generating drive force for the vehicle, such as an internal combustion engine or a drive motor, a drive force transmission mechanism for transmitting drive force to the wheels, a steering mechanism for adjusting the steering angle of the vehicle, and a braking device for generating braking force for the vehicle. The drivetrain control unit 7100 may also function as a control device for an ABS (Antilock Brake System) or an ESC (Electronic Stability Control), etc.

[0143] A vehicle state detection unit 7110 is connected to the drivetrain control unit 7100. The vehicle state detection unit 7110 includes at least one of a gyro sensor that detects the angular velocity of the axial rotational motion of the vehicle body, an acceleration sensor that detects the acceleration of the vehicle, or a sensor that detects the amount of operation of the accelerator pedal, the amount of operation of the brake pedal, the steering angle of the steering wheel, the engine rotation speed, the rotation speed of the wheels, etc. The drivetrain control unit 7100 performs arithmetic processing using signals input from the vehicle state detection unit 7110, and controls the internal combustion engine, the drive motor, the electric power steering device, the brake device, etc.

[0144] The body system control unit 7200 controls the operation of various devices equipped in the vehicle body according to various programs. For example, the body system control unit 7200 functions as a control device for a keyless entry system, a smart key system, a power window device, or various lamps such as headlamps, backup lamps, brake lamps, turn signals, and fog lamps. In this case, radio waves transmitted from a portable device that serves as a key or signals from various switches can be input to the body system control unit 7200. The body system control unit 7200 receives these radio waves or signals and controls the vehicle's door lock device, power window device, lamps, etc.

[0145] The battery control unit 7300 controls the secondary battery 7310, which is the power supply source for the drive motor, in accordance with various programs. For example, information such as battery temperature, battery output voltage, or remaining battery capacity is input to the battery control unit 7300 from a battery device equipped with the secondary battery 7310. The battery control unit 7300 performs arithmetic processing using these signals, and controls the temperature regulation of the secondary battery 7310 or a cooling device or the like equipped in the battery device.

[0146] The outside vehicle information detection unit 7400 detects information outside the vehicle equipped with the vehicle control system 7000. For example, at least one of an imaging unit 7410 and an outside vehicle information detection unit 7420 is connected to the outside vehicle information detection unit 7400. The imaging unit 7410 includes at least one of a time-of-flight (ToF) camera, a stereo camera, a monocular camera, an infrared camera, and other cameras. The outside vehicle information detection unit 7420 includes at least one of an environmental sensor for detecting the current weather or climate, or a surrounding information detection sensor for detecting other vehicles, obstacles, pedestrians, etc. around the vehicle equipped with the vehicle control system 7000.

[0147] The environmental sensor may be, for example, at least one of a raindrop sensor that detects rain, a fog sensor that detects fog, a sunshine sensor that detects the degree of sunshine, and a snow sensor that detects snowfall. The surrounding information detection sensor may be at least one of an ultrasonic sensor, a radar device, and a LIDAR (Light Detection and Ranging, Laser Imaging Detection and Ranging) device. The imaging unit 7410 and the outside vehicle information detection unit 7420 may each be provided as an independent sensor or device, or may be provided as a device in which multiple sensors or devices are integrated.

[0148] 20 shows an example of the installation positions of the imaging unit 7410 and the vehicle exterior information detection unit 7420. The imaging units 7910, 7912, 7914, 7916, and 7918 are provided, for example, at least one of the front nose, side mirrors, rear bumper, back door, and upper part of the windshield inside the vehicle cabin of the vehicle 7900. The imaging unit 7910 provided on the front nose and the imaging unit 7918 provided on the upper part of the windshield inside the vehicle cabin mainly acquire images of the front of the vehicle 7900. The imaging units 7912 and 7914 provided on the side mirrors mainly acquire images of the sides of the vehicle 7900. The imaging unit 7916 provided on the rear bumper or back door mainly acquires images of the rear of the vehicle 7900. The imaging unit 7918 provided on the upper part of the windshield inside the vehicle cabin is mainly used to detect leading vehicles, pedestrians, obstacles, traffic lights, traffic signs, lanes, etc.

[0149] 20 shows an example of the imaging ranges of the imaging units 7910, 7912, 7914, and 7916. Imaging range a indicates the imaging range of the imaging unit 7910 provided on the front nose, imaging ranges b and c indicate the imaging ranges of the imaging units 7912 and 7914 provided on the side mirrors, respectively, and imaging range d indicates the imaging range of the imaging unit 7916 provided on the rear bumper or back door. For example, by overlaying the image data captured by the imaging units 7910, 7912, 7914, and 7916, a bird's-eye view image of the vehicle 7900 viewed from above can be obtained.

[0150] The outside vehicle information detection units 7920, 7922, 7924, 7926, 7928, and 7930 provided on the front, rear, sides, corners, and above the windshield inside the vehicle cabin of the vehicle 7900 may be, for example, ultrasonic sensors or radar devices. The outside vehicle information detection units 7920, 7926, and 7930 provided on the front nose, rear bumper, back door, and above the windshield inside the vehicle cabin of the vehicle 7900 may be, for example, LIDAR devices. These outside vehicle information detection units 7920 to 7930 are mainly used to detect preceding vehicles, pedestrians, obstacles, etc.

[0151] Returning to FIG. 19 , the explanation will be continued. The outside-vehicle information detection unit 7400 causes the imaging unit 7410 to capture an image outside the vehicle and receives the captured image data. The outside-vehicle information detection unit 7400 also receives detection information from the connected outside-vehicle information detection unit 7420. If the outside-vehicle information detection unit 7420 is an ultrasonic sensor, a radar device, or a LIDAR device, the outside-vehicle information detection unit 7400 emits ultrasonic waves or electromagnetic waves and receives information on the received reflected waves. Based on the received information, the outside-vehicle information detection unit 7400 may perform object detection processing or distance detection processing for people, vehicles, obstacles, signs, or text on the road surface. Based on the received information, the outside-vehicle information detection unit 7400 may also perform environmental recognition processing for recognizing rainfall, fog, road conditions, etc. Based on the received information, the outside-vehicle information detection unit 7400 may also calculate the distance to an object outside the vehicle.

[0152] The outside vehicle information detection unit 7400 may also perform image recognition processing or distance detection processing to recognize people, vehicles, obstacles, signs, or characters on the road surface based on the received image data. The outside vehicle information detection unit 7400 may perform processing such as distortion correction or alignment on the received image data, and may also generate an overhead image or a panoramic image by combining image data captured by different image capturing units 7410. The outside vehicle information detection unit 7400 may also perform viewpoint conversion processing using image data captured by different image capturing units 7410.

[0153] The interior information detection unit 7500 detects information inside the vehicle. A driver state detection unit 7510 that detects the driver's state is connected to the interior information detection unit 7500, for example. The driver state detection unit 7510 may include a camera that captures an image of the driver, a biosensor that detects the driver's biometric information, or a microphone that collects sound from within the vehicle cabin. The biosensor is provided, for example, on the seat or steering wheel, and detects the biometric information of a passenger sitting in the seat or the driver gripping the steering wheel. The interior information detection unit 7500 may calculate the driver's level of fatigue or concentration based on the detection information input from the driver state detection unit 7510, or may determine whether the driver is dozing off. The interior information detection unit 7500 may perform processing such as noise canceling on the collected audio signal.

[0154] The integrated control unit 7600 controls the overall operation of the vehicle control system 7000 according to various programs. An input unit 7800 is connected to the integrated control unit 7600. The input unit 7800 may be implemented by a device that can be operated by a passenger, such as a touch panel, a button, a microphone, a switch, or a lever. Data obtained by voice recognition of a voice input through a microphone may be input to the integrated control unit 7600. The input unit 7800 may be, for example, a remote control device using infrared or other radio waves, or an externally connected device such as a mobile phone or a personal digital assistant (PDA) that can operate the vehicle control system 7000. The input unit 7800 may be, for example, a camera, in which case the passenger can input information using gestures. Alternatively, data obtained by detecting the movement of a wearable device worn by the passenger may be input. Furthermore, the input unit 7800 may include, for example, an input control circuit that generates an input signal based on information input by the passenger using the input unit 7800 and outputs the input signal to the integrated control unit 7600. Passengers and the like operate this input unit 7800 to input various data to the vehicle control system 7000 and to instruct processing operations.

[0155] The storage unit 7690 may include a ROM (Read Only Memory) that stores various programs executed by the microcomputer, and a RAM (Random Access Memory) that stores various parameters, calculation results, sensor values, etc. The storage unit 7690 may also be realized by a magnetic storage device such as an HDD (Hard Disc Drive), a semiconductor storage device, an optical storage device, a magneto-optical storage device, or the like.

[0156] The general-purpose communication I / F 7620 is a general-purpose communication I / F that mediates communication with various devices present in the external environment 7750. The general-purpose communication I / F 7620 may implement a cellular communication protocol such as GSM (Global System of Mobile communications), WiMAX (registered trademark), LTE (Long Term Evolution), or LTE-Advanced (LTE-A), or other wireless communication protocols such as a wireless LAN (also referred to as Wi-Fi (registered trademark)) or Bluetooth (registered trademark). The general-purpose communication I / F 7620 may connect to a device (e.g., an application server or a control server) present on an external network (e.g., the Internet, a cloud network, or an operator-specific network) via, for example, a base station or an access point. In addition, the general-purpose communication I / F 7620 may connect to a terminal located near the vehicle (for example, a terminal of a driver, pedestrian, or store, or an MTC (Machine Type Communication) terminal) using, for example, P2P (Peer To Peer) technology.

[0157] The dedicated communication I / F 7630 is a communication I / F that supports a communication protocol designed for use in vehicles. The dedicated communication I / F 7630 may implement a standard protocol such as WAVE (Wireless Access in Vehicle Environment), which is a combination of a lower layer IEEE 802.11p and an upper layer IEEE 1609, DSRC (Dedicated Short Range Communications), or a cellular communication protocol. The dedicated communication I / F 7630 typically performs V2X communication, which is a concept including one or more of vehicle-to-vehicle communication, vehicle-to-infrastructure communication, vehicle-to-home communication, and vehicle-to-pedestrian communication.

[0158] The positioning unit 7640 performs positioning by receiving, for example, GNSS signals from GNSS (Global Navigation Satellite System) satellites (for example, GPS signals from GPS (Global Positioning System) satellites), and generates position information including the latitude, longitude, and altitude of the vehicle. Note that the positioning unit 7640 may identify the current position by exchanging signals with a wireless access point, or may obtain position information from a terminal such as a mobile phone, PHS, or smartphone that has a positioning function.

[0159] The beacon receiving unit 7650 receives, for example, radio waves or electromagnetic waves transmitted from radio stations or the like installed on the road, and acquires information such as the current location, congestion, road closures, required travel time, etc. The function of the beacon receiving unit 7650 may be included in the dedicated communication I / F 7630 described above.

[0160] The in-vehicle device I / F 7660 is a communication interface that mediates connections between the microcomputer 7610 and various in-vehicle devices 7760 present in the vehicle. The in-vehicle device I / F 7660 may establish wireless connections using wireless communication protocols such as wireless LAN, Bluetooth (registered trademark), NFC (Near Field Communication), or WUSB (Wireless USB). Furthermore, the in-vehicle device I / F 7660 may establish a wired connection such as USB (Universal Serial Bus), HDMI (High-Definition Multimedia Interface), or MHL (Mobile High-Definition Link) via a connection terminal (and a cable, if necessary) not shown. The in-vehicle device 7760 may include, for example, at least one of a mobile device or a wearable device owned by a passenger, or an information device carried into or attached to the vehicle. The in-vehicle device 7760 may also include a navigation device that searches for a route to an arbitrary destination. The in-vehicle device I / F 7660 exchanges control signals or data signals with these in-vehicle devices 7760.

[0161] The in-vehicle network I / F 7680 is an interface that mediates communication between the microcomputer 7610 and the communication network 7010. The in-vehicle network I / F 7680 transmits and receives signals in accordance with a predetermined protocol supported by the communication network 7010.

[0162] The microcomputer 7610 of the integrated control unit 7600 controls the vehicle control system 7000 in accordance with various programs based on information acquired via at least one of the general-purpose communication I / F 7620, the dedicated communication I / F 7630, the positioning unit 7640, the beacon receiving unit 7650, the in-vehicle device I / F 7660, and the in-vehicle network I / F 7680. For example, the microcomputer 7610 may calculate control target values ​​for the driving force generating device, the steering mechanism, or the braking device based on the acquired information inside and outside the vehicle, and output control commands to the drivetrain control unit 7100. For example, the microcomputer 7610 may perform cooperative control aimed at realizing functions of an Advanced Driver Assistance System (ADAS), including vehicle collision avoidance or impact mitigation, following driving based on the following distance, vehicle speed maintenance driving, vehicle collision warning, vehicle lane departure warning, etc. In addition, the microcomputer 7610 may perform cooperative control for the purpose of autonomous driving, in which the vehicle travels autonomously without relying on driver operation, by controlling a driving force generating device, a steering mechanism, a braking device, etc. based on information acquired about the vehicle's surroundings.

[0163] The microcomputer 7610 may generate three-dimensional distance information between the vehicle and objects such as surrounding structures and people, and create local map information including information about the vicinity of the vehicle's current location, based on information acquired via at least one of the general-purpose communication I / F 7620, the dedicated communication I / F 7630, the positioning unit 7640, the beacon receiving unit 7650, the in-vehicle device I / F 7660, and the in-vehicle network I / F 7680. Furthermore, the microcomputer 7610 may predict dangers, such as a vehicle collision, the approach of a pedestrian, or entry into a closed road, based on the acquired information, and generate a warning signal. The warning signal may be, for example, a signal for generating a warning sound or turning on a warning lamp.

[0164] The audio / image output unit 7670 transmits at least one of audio and image output signals to an output device capable of visually or audibly notifying vehicle occupants or the outside of the vehicle of information. In the example of FIG. 19 , an audio speaker 7710, a display unit 7720, and an instrument panel 7730 are illustrated as output devices. The display unit 7720 may include, for example, at least one of an on-board display and a head-up display. The display unit 7720 may have an AR (Augmented Reality) display function. The output device may also be other devices, such as headphones, a wearable device such as an eyeglass-type display worn by the occupant, a projector, or a lamp. When the output device is a display device, the display device visually displays results obtained by various processes performed by the microcomputer 7610 or information received from other control units in various formats, such as text, images, tables, and graphs. When the output device is an audio output device, the audio output device converts audio signals, such as reproduced audio data or acoustic data, into analog signals and audibly outputs the analog signals.

[0165] In the example shown in FIG. 19 , at least two control units connected via the communication network 7010 may be integrated into a single control unit. Alternatively, each control unit may be composed of multiple control units. Furthermore, the vehicle control system 7000 may include another control unit not shown. In the above description, some or all of the functions performed by one of the control units may be assigned to another control unit. In other words, as long as information is transmitted and received via the communication network 7010, predetermined arithmetic processing may be performed by one of the control units. Similarly, a sensor or device connected to one of the control units may be connected to another control unit, and multiple control units may transmit and receive detection information to and from each other via the communication network 7010.

[0166] A computer program for realizing each function of the distance measuring device 40 according to this embodiment described with reference to FIG. 17 can be implemented in any control unit or the like. A computer-readable recording medium storing such a computer program can also be provided. Examples of the recording medium include a magnetic disk, an optical disk, a magneto-optical disk, and a flash memory. The computer program may also be distributed, for example, via a network without using a recording medium.

[0167] In the vehicle control system 7000 described above, the distance measuring device 40 according to this embodiment described using Fig. 17 can be applied to the integrated control unit 7600 of the application example shown in Fig. 19. For example, the control unit 9 of the distance measuring device 40 corresponds to the microcomputer 7610, memory unit 7690, and in-vehicle network I / F 7680 of the integrated control unit 7600.

[0168] Furthermore, at least some of the components of the distance measuring device 40 described with reference to Fig. 17 may be realized in a module (for example, an integrated circuit module configured on a single die) for the integrated control unit 7600 shown in Fig. 19. Alternatively, the distance measuring device 40 described with reference to Fig. 17 may be realized by multiple control units of the vehicle control system 7000 shown in Fig. 19.

[0169] The present technology can be configured as follows:

[0170] (1) A plurality of light-emitting elements arranged in a two-dimensional array, each having a first terminal and a second terminal; a plurality of first terminal wirings including M first wirings (M is an integer of 2 or more) extending in a first direction and N second wirings (N is an integer of 2 or more) extending in a second direction intersecting the first direction and electrically connected to the M first wirings, respectively, and electrically connected to the first terminals of the light-emitting elements; a plurality of second terminal wirings electrically connected to the second terminals of the light-emitting elements, each electrically connected to P (P is an integer of 2 or more) of the light-emitting elements; a plurality of selection circuits respectively connected to one of the plurality of first terminal wirings and the plurality of second terminal wirings, and selecting the corresponding light-emitting elements; a plurality of drive circuits respectively connected to the other of the plurality of first terminal wirings and the plurality of second terminal wirings, and driving the corresponding light-emitting elements; a plurality of capacitors respectively connected to one of the first terminal wirings and the second terminal wirings, and storing electric charges for passing current through the plurality of light-emitting elements; and a first substrate on which the plurality of light-emitting elements are arranged. a second substrate stacked on the first substrate and having the plurality of drive circuits arranged thereon, wherein the plurality of capacitors are arranged so as to at least partially overlap the first substrate and the second substrate in a planar view, wherein N is an integer that is the same as or different from M, and wherein P is an integer that is the same as or different from at least one of M and N. (2) The light-emitting device according to (1), wherein the second substrate has the plurality of capacitors. (3) The light-emitting device according to (2), wherein the second substrate has the plurality of capacitors arranged on a layer separate from the plurality of drive circuits. (4) The light-emitting device according to (3), wherein the plurality of capacitors are arranged on a wiring layer of the second substrate. (5) The light-emitting device according to (1), wherein the first substrate has the plurality of capacitors. (6) The light-emitting device according to (5), wherein the first substrate has the plurality of capacitors arranged on a layer separate from the plurality of light-emitting elements. (7) The light-emitting device according to (6), wherein the plurality of capacitors are arranged on a wiring layer of the first substrate.(8) The light-emitting device according to (1), further comprising a third substrate stacked between the first substrate and the second substrate, the third substrate having the plurality of capacitors. (9) The light-emitting device according to (1), further comprising: a plurality of capacitors disposed on a surface of the second substrate opposite to a surface facing the first substrate. (10) The light-emitting device according to (9), further comprising: a via penetrating the second substrate; (11) The light-emitting device according to any one of (1) to (10), further comprising: a MIM (Metal-Insulator-Metal) structure, a MOM (Metal-Oxide-Metal) structure, a trench structure, or a wiring capacitance; (12) The light-emitting device according to any one of (1) to (11), further comprising: a capacitance selector that selects one of two or more capacitors having different capacitances, the plurality of capacitors including the capacitor selected by the capacitance selector. (13) The light-emitting device according to any one of (1) to (12), wherein the second substrate includes a power supply circuit that adjusts a voltage level of a reference voltage used to store electric charges in the plurality of capacitors.(14) A two-dimensional array of light-emitting elements, each having a first terminal and a second terminal; a plurality of first terminal wirings including M first wirings (M is an integer of 2 or more) extending in a first direction and N second wirings (N is an integer of 2 or more) extending in a second direction intersecting the first direction and electrically connected to the M first wirings, respectively, the first terminal wirings being electrically connected to the first terminals of the light-emitting elements; a plurality of second terminal wirings electrically connected to the second terminals of the light-emitting elements, each electrically connected to P (P is an integer of 2 or more) of the light-emitting elements; a plurality of selection circuits connected to one of the plurality of first terminal wirings and the plurality of second terminal wirings, respectively, and selecting the corresponding light-emitting elements; a plurality of drive circuits connected to the other of the plurality of first terminal wirings and the plurality of second terminal wirings, respectively, and driving the corresponding light-emitting elements; a plurality of capacitors electrically connected to one of the first terminal wirings and the second terminal wirings, and storing electric charges for passing current through the plurality of light-emitting elements; and a first substrate on which the plurality of light-emitting elements are arranged. A light-emitting device comprising: a second substrate stacked on the first substrate and on which the plurality of drive circuits are arranged, the second substrate having a power supply circuit that adjusts the voltage level of a reference voltage used on at least a portion of the second substrate. (15) The light-emitting device according to (14), wherein the power supply circuit adjusts the voltage level of the reference voltage used to store electric charge in the plurality of capacitors. (16) The light-emitting device according to (15), wherein the power supply circuit adjusts the voltage level of the reference voltage based on a predetermined control signal. (17) The light-emitting device according to (16), wherein the control signal is a signal that controls at least one of a peak value, a pulse width, or a light-emitting timing of a light-emitting pulse waveform of the plurality of light-emitting elements. (18) The light-emitting device according to (16), wherein the control signal is a signal that compensates for the ambient temperature of the plurality of light-emitting elements. (19) The light-emitting device according to (16), wherein the control signal is a signal that controls the light-emitting output of the plurality of light-emitting elements according to the distance to an object.(20) A distance measuring device comprising: a light emitting device that emits light toward an object; and a distance measuring unit that receives light reflected by the object and measures the distance to the object, wherein the light emitting device comprises: a plurality of light emitting elements arranged in a two-dimensional array, each having a first and a second terminal; M first wirings (M is an integer of 2 or more) extending in a first direction; and N second wirings (N is an integer of 2 or more) extending in a second direction intersecting the first direction and electrically connected to the M first wirings, each of the plurality of first terminal wirings being electrically connected to the first terminals of the light emitting elements; a plurality of second terminal wirings electrically connected to the second terminals of the light emitting elements, each of the plurality of second terminal wirings being electrically connected to P (P is an integer of 2 or more) of the light emitting elements; a plurality of selection circuits respectively connected to one of the plurality of first terminal wirings and the plurality of second terminal wirings and selecting the corresponding light emitting elements; and a plurality of drive circuits respectively connected to the other of the plurality of first terminal wirings and the plurality of second terminal wirings and driving the corresponding light emitting elements. A distance measuring device comprising: a plurality of capacitors electrically connected to one of the first and second terminal wirings and storing electric charges for passing current through the plurality of light-emitting elements; a first substrate on which the plurality of light-emitting elements are arranged; and a second substrate stacked on the first substrate and on which the plurality of drive circuits are arranged, wherein the plurality of capacitors are arranged so that at least a portion of them overlap with the first substrate and the second substrate when viewed in a plane.

[0171] The aspects of the present disclosure are not limited to the individual embodiments described above, but include various modifications that may be conceived by those skilled in the art, and the effects of the present disclosure are not limited to the above-described contents. In other words, various additions, modifications, and partial deletions are possible within the scope of the conceptual idea and intent of the present disclosure, which is derived from the contents defined in the claims and their equivalents.

[0172] REFERENCE SIGNS LIST 1, 1a, 1b, 1c, 1d, 1e Light emitting device, 2 Light emitting section, 3 Driving section, 4 Power supply circuit, 5 Light emitting side optical system, 6 Light receiving side optical system, 7 Light receiving section, 8 Signal processing section, 9 Control section, 9a Distance measuring section, 10 Temperature detection section, 11 LD chip, 12 LDD substrate, 18 Substrate, 19 Switch, 20 Mesa section, 21 Substrate, 22 Stacked film, 23 Light emitting element, 24 Transistor, 31 First anode wiring, 31a First horizontal wiring, 31b First vertical wiring, 32 Second anode wiring, 33 Third anode wiring, 33 Anode wiring, 33a Third horizontal wiring, 33b Third vertical wiring, 34 First capacitor, 35 Second capacitor, 36 Third capacitor, 37 First selection circuit, 37a Transistor, 37b Transistor, 38 Second selection circuit, 38a Transistor, 38b Transistor, 39 Third selection circuit, 39a Transistor, 39b Transistor, 40 Distance measuring device, 41 Cathode wiring, 41' Anode wiring, 42 Gate wiring, 42' Gate wiring, 47 Anode electrode, 48 Cathode electrode, 49 Pad, 50 Bonding layer, 61 First transistor, 62 Second transistor, 63 Third transistor, 64 First gate wiring, 65 Second gate wiring, 66 Third gate wiring, 67 Capacitor, 68 Selection circuit, 68a Transistor, 68b Transistor, 71 First voltage detection circuit, 72 Second voltage detection circuit, 73 Third voltage detection circuit, 99 Control unit, 100 Light emitting device

Claims

1. A plurality of light-emitting elements arranged in a two-dimensional array, each having a first and second terminal; a plurality of first terminal wirings (M is an integer of 2 or more) extending in a first direction and N second wirings (N is an integer of 2 or more) extending in a second direction intersecting the first direction and electrically connected to each of the M first wirings, the plurality of first terminal wirings being electrically connected to the first terminals of the light-emitting elements; a plurality of second terminal wirings electrically connected to the second terminals of the light-emitting elements, each of the plurality of second terminal wirings being electrically connected to P (P is an integer of 2 or more) of the light-emitting elements; a plurality of selection circuits respectively connected to one of the plurality of first terminal wirings and the plurality of second terminal wirings, and selecting corresponding light-emitting elements; a plurality of drive circuits respectively connected to the other of the plurality of first terminal wirings and the plurality of second terminal wirings, and driving corresponding light-emitting elements; a plurality of capacitors respectively connected to one of the first and second terminal wirings, and storing electric charges for flowing current through the plurality of light-emitting elements; and a first substrate on which the plurality of light-emitting elements are arranged. a second substrate stacked on the first substrate and on which the plurality of driving circuits are arranged, the plurality of capacitors are arranged so as to overlap at least partially with the first substrate and the second substrate when viewed in a plane, N is an integer that is the same as or different from M, and P is an integer that is the same as or different from at least one of M and N.

2. The light emitting device according to claim 1, wherein the second substrate has the plurality of capacitors.

3. The light emitting device according to claim 2, wherein the second substrate has the capacitors arranged in a layer separate from the driving circuits.

4. The light emitting device according to claim 3, wherein the plurality of capacitors are disposed in a wiring layer of the second substrate.

5. The light emitting device according to claim 1, wherein the first substrate includes the plurality of capacitors.

6. The light emitting device according to claim 5, wherein the first substrate has the plurality of capacitors arranged in a layer separate from the plurality of light emitting elements.

7. The light emitting device according to claim 6, wherein the plurality of capacitors are disposed in a wiring layer of the first substrate.

8. The light emitting device according to claim 1, further comprising a third substrate laminated between the first substrate and the second substrate, the third substrate having the plurality of capacitors.

9. The light emitting device according to claim 1, wherein the plurality of capacitors are arranged on a surface of the second substrate opposite to a surface facing the first substrate.

10. The light emitting device according to claim 9, wherein the plurality of capacitors are electrically connected to the one of the first and second terminal wirings by vias penetrating the second substrate.

11. The light emitting device according to claim 1, wherein the plurality of capacitors have a metal-insulator-metal (MIM) structure, a metal-oxide-metal (MOM) structure, a trench structure, or a wiring capacitance.

12. The light emitting device according to claim 1, further comprising a capacitance selector that selects one of two or more capacitors each having a different capacitance, the plurality of capacitors including the capacitor selected by the capacitance selector.

13. The light emitting device according to claim 1, wherein the second substrate has a power supply circuit that adjusts the voltage level of a reference voltage used to store electric charges in the plurality of capacitors.

14. A device comprising: a plurality of light-emitting elements arranged in a two-dimensional array, each having a first terminal and a second terminal; a plurality of first terminal wirings (M is an integer of 2 or more) extending in a first direction, and N second wirings (N is an integer of 2 or more) extending in a second direction intersecting the first direction and electrically connected to the M first wirings, the plurality of first terminal wirings being electrically connected to the first terminals of the light-emitting elements; a plurality of second terminal wirings electrically connected to the second terminals of the light-emitting elements, each of the plurality of second terminal wirings being electrically connected to P (P is an integer of 2 or more) of the light-emitting elements; a plurality of selection circuits respectively connected to one of the plurality of first terminal wirings and the plurality of second terminal wirings, and selecting corresponding light-emitting elements; a plurality of drive circuits respectively connected to the other of the plurality of first terminal wirings and the plurality of second terminal wirings, and driving corresponding light-emitting elements; a plurality of capacitors respectively connected to one of the first and second terminal wirings, and storing electric charges for passing current through the plurality of light-emitting elements; and a first substrate on which the plurality of light-emitting elements are arranged. a second substrate stacked on the first substrate and on which the plurality of drive circuits are arranged, the second substrate having a power supply circuit that adjusts a voltage level of a reference voltage used in at least a portion of the second substrate.

15. The light emitting device according to claim 14, wherein the power supply circuit adjusts a voltage level of the reference voltage used to store electric charge in the plurality of capacitors.

16. The light emitting device according to claim 15, wherein the power supply circuit adjusts the voltage level of the reference voltage based on a predetermined control signal.

17. The light emitting device according to claim 16, wherein the control signal is a signal for controlling at least one of a peak value, a pulse width, or a light emission timing of a light emission pulse waveform of the plurality of light emitting elements.

18. The light emitting device according to claim 16, wherein the control signal is a signal for compensating for an ambient temperature of the plurality of light emitting elements.

19. The light emitting device according to claim 16, wherein the control signal is a signal for controlling the light emission output of the plurality of light emitting elements in accordance with the distance to an object.

20. A distance measuring device comprising: a light emitting device which emits light towards an object; and a distance measuring unit which receives light reflected by the object and measures the distance to the object, the light emitting device comprising: a plurality of light emitting elements arranged in a two-dimensional array, each having a first and second terminal; M first wirings (M is an integer of 2 or more) extending in a first direction; and N second wirings (N is an integer of 2 or more) extending in a second direction intersecting the first direction and electrically connected to each of the M first wirings, the plurality of first terminal wirings being electrically connected to the first terminals of the light emitting elements; a plurality of second terminal wirings electrically connected to the second terminals of the light emitting elements, each of the plurality of second terminal wirings being electrically connected to P of the light emitting elements (P is an integer of 2 or more); a plurality of selection circuits respectively connected to one of the plurality of first terminal wirings and the plurality of second terminal wirings and selecting the corresponding light emitting elements; and a plurality of drive circuits respectively connected to the other of the plurality of first terminal wirings and the plurality of second terminal wirings and driving the corresponding light emitting elements. A distance measuring device comprising: a plurality of capacitors electrically connected to one of the first and second terminal wirings and storing electric charges for flowing current to the plurality of light-emitting elements; a first substrate on which the plurality of light-emitting elements are arranged; and a second substrate stacked on the first substrate and on which the plurality of driving circuits are arranged, wherein the plurality of capacitors are arranged so that at least a portion of them overlap with the first substrate and the second substrate when viewed in a plane.

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