Light-emitting device and measuring device

Abstract

To provide a light-emitting device which is configured to emit light while switching among multiple light-emitting units, and which allows for reducing the distance between the light-emitting units and a drive unit compared with a case where a switching unit for switching among the light-emitting units is provided between the light-emitting units and the drive unit.SOLUTION: A light-emitting device is provided, comprising multiple light-emitting units, a drive unit for driving the light-emitting units by supplying electric current to the light-emitting units, and a switching unit provided on a side opposite the drive unit with respect to the multiple light-emitting units and configured to switch emission among the multiple light-emitting units.SELECTED DRAWING: Figure 5

Description

[Technical Field]

[0001] The present invention relates to a light emitting device and a measurement device. [Background technology]

[0002] Patent document 1 describes a light-emitting element array in which a large number of light-emitting elements whose threshold voltage or threshold current can be controlled externally by light are arranged one-dimensionally, two-dimensionally, or three-dimensionally, and at least a portion of the light emitted from each light-emitting element is incident on other light-emitting elements in the vicinity of each light-emitting element, and a clock line is connected to each light-emitting element to apply a voltage or current from the outside.

[0003] Patent Document 2 describes a self-scanning light-emitting device that has a light-emitting element with a pnpnpn six-layer semiconductor structure, with electrodes provided on the p-type first layer and n-type sixth layer at both ends and the central p-type third layer and n-type fourth layer, with the pn layer performing the light-emitting diode function and the pnpn fourth layer performing the thyristor function.

[0004] Patent Document 3 describes a self-scanning light source head that includes a substrate, surface-emitting semiconductor lasers arranged in an array on the substrate, and thyristors arranged on the substrate as switching elements that selectively turn on and off the light emission of the surface-emitting semiconductor lasers. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Publication No. 01-238962 [Patent Document 2] Japanese Patent Application Laid-Open No. 2001-308385 [Patent Document 3] Japanese Patent Application Laid-Open No. 2009-286048 Summary of the Invention [Problem to be solved by the invention]

[0006] In a method for measuring the three-dimensional shape of an object by irradiating the object with light from a light-emitting device and receiving the light reflected from the object, the rise time of the light pulse irradiated onto the object must be short. To achieve this, it is advisable to shorten the distance between the light-emitting unit and the driver that supplies the current for light emission in the light-emitting device, thereby reducing the inductance. The object of the present invention is to provide a light emitting device that switches between multiple light emitting units to emit light, in which the distance between the light emitting units and the driving unit can be shortened compared to when a switching unit that switches between the light emitting units is provided between the light emitting units and the driving unit. [Means for solving the problem]

[0007] The invention described in claim 1 is Wiring board and a plurality of light-emitting units; and a driving unit that supplies current to the light-emitting units to drive the light-emitting units; Complex number of The aforementioned a switching unit for switching the light emitted by the light emitting unit; A power supply potential is applied a light-emitting electrode; the light-emitting units, the switching unit, and the driving unit are arranged on the wiring board, and the switching unit is provided on the wiring board on the opposite side of the driving unit with respect to the light-emitting units; Light-emitting electrode is an electrode provided in common to the plurality of light-emitting units, and is located at a position on the wiring board different from the position where the driving unit and the switching unit are located. A pad portion is provided on the outer side of the plurality of light emitting portions. The power supply potential is applied via the pad portion. It is a light-emitting device. The invention described in claim 2 is Wiring board and a plurality of light-emitting units; and a driving unit that supplies current to the light-emitting units to drive the light-emitting units; Complex number of The aforementioned a switching unit for switching the light emitted by the light emitting unit; A power supply potential is applied a light-emitting electrode; the light-emitting units, the switching unit, and the driving unit are arranged on the wiring board, the switching unit is provided on the wiring board on the opposite side of the driving unit with respect to the light-emitting units, the light-emitting electrode is an electrode provided in common to the light-emitting units, and has a pad portion on the outside of the light-emitting units, and the power supply potential is applied via the pad portion; The plurality of light emitting portions include first and second edges facing each other, and third and fourth edges facing each other, which connect the first and second edges. Surrounded by the driving unit, the switching unit, and the light-emitting electrode Pad section are light emitting devices provided on different edges. A third aspect of the present invention is the light emitting device according to the second aspect, wherein the drive section and the switching section are provided on the first edge side and the second edge side that face each other. A fourth aspect of the present invention is the light emitting device according to the third aspect, wherein the light emitting electrode has pad portions on both the third edge side and the fourth edge side. The invention described in claim 5 is a light-emitting device described in claim 1, which is provided with wiring connecting each of the plurality of light-emitting units to the switching unit, and the wiring is arranged outside the light-emitting units and along the light-emitting units. A sixth aspect of the present invention is the light emitting device according to the first aspect, wherein the switching section includes a switching element. A seventh aspect of the present invention is the light emitting device according to the sixth aspect, wherein the switching section sequentially transfers the on states of the switching elements provided for the light emitting sections. The invention described in claim 8 is a light-emitting device described in claim 1, wherein the light-emitting portion comprises a light-emitting diode and a thyristor stacked on the light-emitting diode and causing the light-emitting diode to emit light when turned on. A ninth aspect of the present invention is the light emitting device according to the eighth aspect, wherein the light emitting diode is a vertical cavity surface emitting laser. The invention described in claim 10 is a measurement device comprising an illuminating device described in any one of claims 1 to 9 and a three-dimensional sensor that receives reflected light from a measured object irradiated with light emitted from the illuminating device. [Effects of the Invention]

[0008] According to the first aspect of the invention, the distance between the light emitting unit and the driving unit can be made shorter than when a switching unit for switching the light emitting unit is provided between the light emitting unit and the driving unit. Claim 2 According to the invention described in (1), the planar shape of the light emitting device can be made smaller than when the drive section, the switching section, and the light emitting electrode are not provided on different edge sides. Claim 3 According to the invention described in the item 1, the distance between the plurality of light emitting units and the driving unit can be made shorter than when the driving unit and the switching unit are not provided on the first edge side and the second edge side that face each other. Claim 4According to the invention described in the item (1), bias in the supply of current to the light-emitting section 22 is suppressed compared to when the pad sections are not provided on both the third edge side and the fourth edge side. Claim 5 According to the invention described in the item (1), the light emitting elements can be provided at a higher density in the light emitting section compared to when the wiring is provided on the surface side of the light emitting section. Claim 6 According to the invention described in the above, it is not necessary to provide a switching element outside the light emitting device. Claim 7 According to the invention described in (1), it is easier to control the light emitting portion to emit light than when the ON states of the switching elements are not transferred in sequence. Claim 8 According to the invention described in the item (1), it is easier to control the light emission of the light emitting diode compared to when the light emitting diode and the thyristor are not stacked. Claim 9 According to the invention described in the above, the optical output can be increased compared to a case where the vertical cavity surface emitting laser is not used. Claim 10 According to the invention described in the above, it is possible to measure a three-dimensional shape. [Brief explanation of the drawings]

[0009] [Figure 1] FIG. 1 illustrates an example of an information processing apparatus. [Figure 2] FIG. 1 is a block diagram illustrating a configuration of an information processing device. [Figure 3] FIG. 2 is a perspective view illustrating a state in which a light source of the light emitting device irradiates divided light onto an irradiation area. [Figure 4] FIG. 2 is a diagram illustrating a light source in the light emitting device. [Figure 5] 1 is a diagram illustrating the arrangement of a light source and a driving unit in a light-emitting device. FIG. [Figure 6] 1 is an equivalent circuit of a light emitting device to which the present embodiment is applied. [Figure 7] 10 is a timing chart illustrating the operation of the light emitting device. [Figure 8] FIG. [Figure 9]9A and 9B are cross-sectional views of the light-emitting part, where (a) is a cross-sectional view taken along line IXA-IXA in FIG. 8, and (b) is a cross-sectional view taken along line IXB-IXB in FIG. [Figure 10] 10A and 10B are diagrams showing a light emitting device which is a modified example of the light emitting device to which the present embodiment is applied. [Figure 11] 10A and 10B are diagrams showing a light emitting device which is a modified example of the light emitting device to which the present embodiment is applied. [Figure 12] 10 is an equivalent circuit diagram showing a light emitting device which is a modified example of the light emitting device to which the present embodiment is applied. [Figure 13] 10 is an equivalent circuit diagram showing a light emitting device which is a modified example of the light emitting device to which the present embodiment is applied. DETAILED DESCRIPTION OF THE INVENTION

[0010] Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. Among measurement devices that measure the three-dimensional shape (hereinafter referred to as 3D shape) of a measurement target, there are devices that measure the three-dimensional shape based on the so-called ToF (Time of Flight) method, which relies on the time of flight of light. The ToF method measures the time from when light is emitted from a light-emitting device included in the measurement device to when it is reflected by the measurement target and received by a three-dimensional sensor (hereinafter referred to as 3D sensor) included in the measurement device. The 3D shape of the measurement target is then identified from the measured time. Note that the object whose 3D shape is being measured is referred to as the measurement target. A three-dimensional shape is sometimes referred to as a three-dimensional image. Measuring a three-dimensional shape is sometimes referred to as three-dimensional measurement, 3D measurement, or 3D sensing.

[0011] Such a measurement device is applied to recognize an object to be measured from the measured 3D shape. For example, it is installed in a portable information processing device and used to recognize the face of a user attempting to access the device. That is, the device acquires the 3D shape of the face of the accessing user, identifies whether the access is permitted, and allows use of the device (portable information processing device) only if it is recognized that the user is authorized to access the device. This measurement device can also be used in cases where the 3D shape of an object needs to be measured continuously, such as in augmented reality (AR), regardless of the distance to the object.

[0012] Such a measuring device can be applied to information processing devices other than portable information processing devices, such as personal computers (PCs).

[0013] Here, the information processing device will be described as a portable information processing device as an example, and the device will be described as authenticating a user by recognizing a face captured as a 3D shape.

[0014] (Information processing device 1) 1 is a diagram showing an example of an information processing device 1. As described above, the information processing device 1 is, for example, a portable information processing device. The information processing device 1 includes a user interface unit (hereinafter referred to as a UI unit) 2 and an optical device 3 that measures 3D shapes. The UI unit 2 integrates, for example, a display device that displays information to the user and an input device into which instructions for information processing are input by user operation. The display device is, for example, a liquid crystal display or an organic EL display, and the input device is, for example, a touch panel.

[0015] The optical device 3 includes a light emitting device 4 and a 3D sensor 5. The light emitting device 4 emits light toward the object to be measured, in this example, a face. The 3D sensor 5 acquires the light reflected back from the face. Here, the 3D shape is measured based on the so-called ToF method, which uses the time of flight of light. The face is then recognized from the 3D shape. As mentioned above, the 3D shape may be measured using an object other than a face as the object to be measured. A measurement device that measures the 3D shape includes the light emitting device 4 and the 3D sensor 5.

[0016] The information processing device 1 is a computer including a CPU, a ROM, a RAM, etc. The ROM includes a non-volatile rewritable memory, such as a flash memory. Programs and constants stored in the ROM are loaded into the RAM, and the CPU executes the programs, thereby operating the information processing device 1 and performing various types of information processing.

[0017] FIG. 2 is a block diagram illustrating the configuration of the information processing device 1. As shown in FIG. The information processing device 1 includes the optical device 3, a measurement control unit 8, and a system control unit 9. The measurement control unit 8 controls the optical device 3 to measure the 3D shape. The measurement control unit 8 includes a 3D shape identification unit 8A. The system control unit 9 controls the entire information processing device 1 as a system. The system control unit 9 includes a recognition processing unit 9A. The system control unit 9 is connected to a UI unit 2, a speaker 9B, a two-dimensional camera (referred to as a 2D camera in FIG. 2) 9C, and the like.

[0018] A 3D shape identification unit 8A included in the measurement control unit 8 measures the 3D shape of the object to be measured from the light reflected from the object to be measured and identifies the 3D shape of the object to be measured. A recognition processing unit 9A included in the system control unit 9 recognizes the object to be measured, in this example, a face, from the 3D shape identified by the 3D shape identification unit 8A. Then, based on the recognized face, it is determined whether the user is authorized to access the object.

[0019] The light-emitting device 4 included in the optical device 3 includes a wiring substrate 10, a light source 20, a light diffusion member 30, and a drive unit 50. The light source 20 and the drive unit 50 are disposed on the wiring substrate 10. The light source 20 and the drive unit 50 are connected by wiring provided on the wiring substrate 10. The drive unit 50 supplies a current to the light source 20 for light emission. The light diffusion member 30 is inserted into the path of light emitted by the light source 20 and directs the light emitted by the light source 20 in a desired direction. For example, the light diffusion member 30 is held by a holder 40 provided on the wiring substrate 10 and covers the light source 20. The wiring substrate 10 may include a resistive element or a capacitive element to operate the light source 20 and the drive unit 50. The light source 20 may also be provided on a heat dissipation base material having a higher thermal conductivity than the wiring substrate 10. Examples of heat dissipation substrates include alumina (Al2O3), which has a thermal conductivity of 20 to 30 W / m·K, silicon nitride (Si3N4), which has a thermal conductivity of approximately 85 W / m·K, or aluminum nitride (AlN), which has a thermal conductivity of 150 to 250 W / m·K, compared to the thermal conductivity of the insulating layer called FR-4 used in wiring board 10, which is approximately 0.4 W / m·K. Note that although wiring is provided on wiring board 10 in the above description, wiring board 10 may also be a substrate without wiring. As long as light source 20 and drive unit 50 are connected, the substrate may be one that can support light source 20, drive unit 50, etc.

[0020] Fig. 3 is a perspective view illustrating a state in which light source 20 of light emitting device 4 divides and irradiates irradiation area 100. Fig. 3 shows light source 20 of light emitting device 4. In Fig. 3, at the part of light source 20, the rightward direction on the paper surface is defined as the x direction, the upward direction on the paper surface is defined as the y direction, and the direction toward irradiation area 100 is defined as the z direction.

[0021] As an example, the light source 20 includes 12 light-emitting units 22. The 12 light-emitting units 22 are collectively referred to as the light-emitting unit 21. The 12 light-emitting units 22 are arranged in a matrix of four in the x direction and three in the y direction. Each light-emitting unit 22 may emit light individually, or multiple light-emitting units 22 may emit light simultaneously. Furthermore, all of the light-emitting units 22 may emit light simultaneously.

[0022] The illumination area 100 is a range onto which light emitted by the light source 20 is irradiated in order to measure the 3D shape of the object to be measured. Here, each light-emitting unit 22 has a different illumination range. That is, the light source 20 irradiates the illumination area 100 in a divided manner. The light emitted by the light-emitting unit 22 passes through a light diffusion member 30 (see FIG. 2), thereby setting the direction of illumination and / or the spread of the light. Note that the light diffusion member 30 may be replaced by an optical member such as a diffractive optical element (DOE) that changes the direction of incident light and emits it in different directions, or a transparent member such as a condenser lens, a microlens, or a protective cover.

[0023] 4 is a diagram illustrating the light source 20 in the light emitting device 4. The x, y, and z directions in FIG. 4 are the same as those in FIG. The light source 20 includes a light emitting section 21 in which a plurality of light emitting sections 22 are arranged, a switching section 23 that switches between the light emitting sections 22 that emit light, and wiring 25 that connects the light emitting sections 22 and the switching section 23.

[0024] As described above, the light output unit 21 includes 12 light emitting units 22 arranged in a matrix of four in the x direction and three in the y direction. Here, to distinguish between the light emitting units 22, they are denoted as light emitting units 22-1 to 22-12. The circle marks on the light emitting units 22 are light emitting diodes LED, which are an example of a light emitting element. That is, each light emitting unit 22 includes a plurality of light emitting diodes LED. The light emitting units 22 may include the same number of light emitting elements or different numbers of light emitting elements. The light emitting unit 22 may include only one light emitting element. A light-emitting electrode 72 is provided on the light-emitting portion 22 (on the z-direction side) in common to all of the light-emitting portions 22. Pad portions 72A and 72B are provided on the ±y-direction sides of the light-emitting electrode 72 to which wiring for supplying a current for light emission is connected. Note that only the frame of the light-emitting electrode 72 is shown so that the light-emitting portion 22 below can be seen.

[0025] The switching unit 23 includes signal terminals 24-1 to 24-12 that supply switching signals φf1 to φf12 to the light-emitting units 22-1 to 22-12, respectively. When the switching signals φf1 to φf12 are not distinguished, they are referred to as switching signals φf, and when the signal terminals 24-1 to 24-12 are not distinguished, they are referred to as signal terminals 24. The switching unit 23 is arranged together on the x-direction side of the light-emitting unit 21, which includes multiple light-emitting units 22. The signal terminals 24 of the switching unit 23 may be arranged in a row on the y-direction side. In this case, the length in the x-direction is shorter than when they are not arranged in a single row.

[0026] The light-emitting unit 22 of the light output unit 21 and the signal terminal 24 of the switching unit 23 are connected by a wiring 25, and a switching signal φf is supplied from the signal terminal 24. That is, the light-emitting unit 22-1 and the signal terminal 24-1 are connected by a wiring 25-1, and a switching signal φf1 is supplied. The light-emitting unit 22-2 and the signal terminal 24-2 are connected by a wiring 25-2, and a switching signal φf2 is supplied from the signal terminal 24-2. Note that in FIG. 4, the wirings 25-1 and 25-2 are shown, and the other wirings 25-3 to 25-12 are not shown.

[0027] The wiring 25 is provided outside the light-emitting section 22 and along the light-emitting section 22. This allows the light-emitting diodes LED to be provided at a higher density than when the wiring is provided inside, i.e., on the surface, of the light-emitting section 22. In addition, in FIG. 4, the length of the region including the light-emitting section 21 and the switching section 23 in the x direction is longer than the length in the y direction.

[0028] 5 is a diagram illustrating the arrangement of the light source 20 and the drive unit 50 in the light emitting device 4. The x, y, and z directions in FIG. 5 are the same as those in FIG. Here, the -x direction side of the light emitting unit 21 including the plurality of light emitting parts 22 is denoted as the edge 21a, the +x direction side as the edge 21b, the +y direction side as the edge 21c, and the -y direction side as the edge 21d. The edge 21a and the edge 21b face each other, and the edge 21c and the edge 21d connect the edge 21a and the edge 21b and face each other. That is, the plurality of light emitting parts 22 of the light emitting unit 21 are surrounded by the edges 21a, 21b, 21c, and 21d. And the edge 21a has a length D1, and the edge 21c has a length D2. Here, the length D1 is set shorter than the length D2 (D1 < D2). Here, the edge 21a is an example of the first edge, the edge 21b is an example of the second edge, the edge 21c is an example of the third edge, and the edge 21d is an example of the fourth edge.

[0029] As shown in FIG. 5, the switching unit 23 is disposed at a position opposite to the driving unit 50. That is, the driving unit 50 is provided adjacent to the light emitting part 22 side of the light emitting unit 21. That is, the driving unit 50 is provided on the edge 21a side of the light emitting unit 21, and the switching unit 23 is provided on the edge 21b side of the light emitting unit 21. That is, the driving unit 50 and the switching unit 23 are provided on the opposite edge sides. Thereby, the distance between the driving unit 50 and the light emitting part 22 becomes shorter than the case where the switching unit 23 is provided at a position between the driving unit 50 and the light emitting part 22. Thereby, in the light emitting device 4, the inductance between the driving unit 50 and the light emitting part 22 in the light source 20 becomes smaller, and the rising time of the light pulse becomes shorter. Also, since the 3D sensor 5 is disposed at the position shown in FIG. 1, the 3D sensor 5 is provided on the switching unit 23 side. That is, the driving unit 50, the light emitting part 22, the switching unit 23, and the 3D sensor 5 are arranged in this order.

[0030] Furthermore, the light-emitting electrode 72 has a pad portion 72A provided on the edge 21c side of the light-emitting portion 21 including the light-emitting portion 22, and a pad portion 72B provided on the edge 21d side of the light-emitting portion 21. In other words, the pad portions 72A and 72B are provided outside the light-emitting portion 21 at positions different from the positions where the driver 50 and the switching unit 23 are provided relative to the light-emitting portion 21. If the pad portions 72A and 72B were provided at the position where the switching unit 23 or the driver 50 is provided, there is a risk that connection to the pad portions 72A and 72B may be hindered by the switching unit 23 or the driver 50. In other words, connection to the pad portions 72A and 72B is easier than when the pad portions 72A and 72B are provided at the position where the switching unit 23 or the driver 50 is provided. The pad portions 72A and 72B are provided on both the edge 21c and the edge 21d. Therefore, current is supplied from both sides of the light-emitting electrode 72. This reduces bias in the supply of current to the light-emitting section 22 compared to when the pad section is provided on either the edge 21c or the edge 21d. That is, the drive section 50, the switching section 23, and the light-emitting electrode 72 are provided on different edge sides of the light-emitting section 21. This allows the planar shape of the light-emitting device 4 to be small.

[0031] Fig. 6 is an equivalent circuit of a light emitting device 4 to which this embodiment is applied. Fig. 6 shows a light source 20 and a driving unit 50 in the light emitting device 4. Note that Fig. 6 also shows a measurement control unit 8 that controls the light emitting device 4.

[0032] As described above, the light source 20 includes a light emitting unit 21 and a switching unit 23 that switches between the plurality of light emitting units 22 in the light emitting unit 21. FIG. 6 shows three light emitting units 22 (referred to as light emitting units 22-1, 22-2, and 22-3). As shown in light emitting unit 22-1, each light emitting unit 22 includes a plurality of light emitting diodes LED. Each light emitting unit 22 includes a drive thyristor S commonly connected to the plurality of light emitting diodes LED.

[0033] The light emitting diode LED is, for example, a vertical cavity surface emitting laser (VCSEL). In the following description, the light emitting diode LED is assumed to be a vertical cavity surface emitting laser (VCSEL). A vertical cavity surface emitting laser (VCSEL) is a surface emitting laser element that has a light emitting layer serving as a light emitting region between a lower multilayer reflector and an upper multilayer reflector stacked on a substrate, and emits laser light in a direction perpendicular to the surface. The vertical cavity surface emitting laser (VCSEL) here has a λ resonator structure. Note that the light emitting element may be other light emitting devices such as laser diodes other than the vertical cavity surface emitting laser (VCSEL). In the following, the vertical cavity surface emitting laser (VCSEL) may be referred to as VCSEL.

[0034] The driving section 50 includes a MOS transistor 51 as an example of a driving element, and a signal generating circuit 52. The driving element may be an insulated gate bipolar transistor (IGBT) or the like.

[0035] The plurality of light-emitting diodes LED and the drive thyristor S are connected in series. That is, the plurality of light-emitting diodes LED are connected in parallel, and the anodes ([A]) of the light-emitting diodes LED are connected to the cathodes ([K]) of the drive thyristors S. Similarly, the cathodes ([K]) of the light-emitting diodes LED are connected in parallel and connected to the drains ([D]) of the MOS transistors 51 in the drive unit 50. The source ([S]) of the MOS transistors 51 is connected to a reference potential wiring 71 that supplies a reference potential GND (0V).

[0036] The anode ([A]) of the drive thyristor S is connected to the light-emitting electrode 72 to which the power supply potential VLD is supplied. The gate ([G]) of the drive thyristor S is connected to the signal terminal 24 of the switching unit 23. That is, in the light-emitting unit 22-1, the gate ([G]) of the drive thyristor S is connected to the signal terminal 24-1 and is supplied with the switching signal φf1. The same applies to the other light-emitting units 22.

[0037] The signal generating circuit 52 in the driving section 50 supplies the gate ([G]) of the MOS transistor 51 with an On signal (On) that turns the MOS transistor 51 on and an Off signal (Off) that turns the MOS transistor 51 off.

[0038] The driving method of the light emitting device 4 described above is so-called low-side driving. Low-side driving is preferable when it is desired to drive the light emitting diode LED at higher speed. Low-side driving refers to a configuration in which a driving element such as a MOS transistor 51 is located downstream of the current path of a driving target such as a light emitting diode LED.

[0039] The operation of the light emitting device 4 will now be described. (Drive thyristor S) The drive thyristor S is a semiconductor element having three terminals: an anode ([A]), a cathode ([K]), and a gate ([G]). As will be described later, the drive thyristor S is configured by laminating an n-cathode layer 85, a p-gate layer 86, an n-gate layer 87, and a p-anode layer 88 made of GaAs, AlGaAs, AlAs, or the like. In other words, the drive thyristor S has an npnp structure. As an example, the following description will be given assuming that the forward voltage (built-in potential) Vd of the p-n junction between the p-type semiconductor layer (p-gate layer 86, p-anode layer 88) and the n-type semiconductor layer (n-cathode layer 85, n-gate layer 87) is 1.5 V.

[0040] The drive thyristor S has a gate ([G]) provided in the n-gate layer 87. First, assume that the drive thyristor S is in an off state, where a voltage is applied between the anode ([A]) and cathode ([K]) of the drive thyristor S but no current flows. When a forward bias is applied between the p-anode layer 88, which is the anode ([A]), and the n-gate layer 87, which is the gate ([G]), the drive thyristor S transitions to an on state, where current flows. That is, in FIG. 6, when the gate ([G]) becomes a voltage that is significantly lower than the potential of the anode ([A]) by a forward voltage Vd, the drive thyristor S transitions from an off state to an on state. Then, a forward voltage Vd is applied between the anode ([A]) and the cathode ([K]). For example, if the anode ([A]) is 5 V, the drive thyristor S transitions from an off state to an on state when the gate ([G]) becomes less than 3.5 V. Also, if the anode ([A]) is 10V, when the gate ([G]) becomes less than 8.5V, the drive thyristor S transitions from the OFF state to the ON state.

[0041] The gate ([G]) is connected to a signal terminal 24, and a switching signal φf is supplied to the signal terminal 24. That is, the transition of the drive thyristor S from the OFF state to the ON state is controlled by the switching signal φf.

[0042] (Light Emitting Diode LED) A light-emitting diode LED is a semiconductor device with two terminals: an anode ([A]) and a cathode ([K]). Therefore, a light-emitting diode LED emits light when a voltage greater than the forward voltage Vd is applied between the anode ([A]) and the cathode ([K]) and a current sufficient to emit light flows.

[0043] (Operation of light emitting unit 22) As shown in Fig. 6, the light-emitting unit 22 has a drive thyristor S and a light-emitting diode LED connected in series. A power supply potential VLD is applied to a light-emitting electrode 72 to which the anode ([A]) of the drive thyristor S is connected. The cathode ([K]) of the light-emitting diode LED is connected to the drain ([D]) of the MOS transistor 51 of the drive unit 50. A reference potential GND (0V) is supplied to the source ([S]) of the MOS transistor 51 of the drive unit 50. The reference potential GND is the ground potential.

[0044] Here, assume that an On signal is input from the signal generating circuit 52 to the gate ([G]) of the MOS transistor 51, turning the MOS transistor 51 on. Then, the cathode ([K]) of the light-emitting diode LED of the light-emitting unit 22 becomes 0 V. Therefore, the power supply potential VLD is applied to the light-emitting unit 22.

[0045] Suppose the power supply potential VLD is 5V. Suppose the switching signal φf is 5V and the drive thyristor S is in the OFF state. Now, the switching signal φf changes to less than 3.5V, which is lower than the power supply potential VLD of the anode ([A]) of the drive thyristor S by an amount that is much lower than the forward voltage Vd. This causes the drive thyristor S to change from the OFF state to the ON state. Then, current flows from the drive thyristor S to the light-emitting diode LED. The cathode ([K]) of the drive thyristor S becomes 3.5V. Therefore, the forward voltage between the anode ([A]) and cathode ([K]) of the light-emitting diode LED becomes equal to or greater than Vd, and the light-emitting diode LED emits light.

[0046] Also, assume that the power supply potential VLD is 10V. Then, assume that the switching signal φf is 10V and the drive thyristor S is in the OFF state. Here, the switching signal φf transitions to less than 8.5V, which is lower than the power supply potential VLD, which is the potential of the anode ([A]) of the drive thyristor S, by an amount that is much lower than the forward voltage Vd. This causes the drive thyristor S to transition from the OFF state to the ON state. Then, current flows from the drive thyristor S to the light-emitting diode LED. The cathode ([K]) of the drive thyristor S becomes 8.5V. Therefore, the forward voltage between the anode ([A]) and cathode ([K]) of the light-emitting diode LED becomes equal to or greater than Vd, and the light-emitting diode LED emits light.

[0047] As explained above, the drive thyristor S in the OFF state maintains the OFF state as long as the voltage applied to the gate ([G]), i.e., the switching signal φf, is equal to or greater than the power supply potential VLD minus the forward voltage Vd. When the switching signal φf becomes less than the power supply potential VLD minus the forward voltage Vd, the drive thyristor S transitions from the OFF state to the ON state.

[0048] When an Off signal is input from the signal generating circuit 52 to the gate ([G]) of the MOS transistor 51, the MOS transistor 51 transitions from the ON state to the ON state. As a result, current stops flowing to the light emitting unit 22, and the light emitting diode LED transitions from the ON state to the OFF state. Note that the drive thyristor S in the ON state does not transition to the OFF state even if the gate ([G]) is set to a value equal to or greater than the power supply potential VLD minus the forward voltage Vd.

[0049] (Timing chart of light emitting device 4) FIG. 7 is a timing chart illustrating the operation of the light-emitting device 4. The horizontal axis represents time a to e, with time t passing. From top to bottom, the diagram shows power supply potential VLD, switching signals φf1 to φf8, switching signals φf9 to φf12, the signal from signal generating circuit 52 of drive unit 50, the states of light-emitting units 22-1 to 22-8, and the states of light-emitting units 22-9 to 22-12. The switching signals φf1 to φf12 are signals that can be switched between H level and L level. Note that the H level is equal to or greater than the value obtained by subtracting forward voltage Vd from power supply potential VLD, and the L level is less than the value obtained by subtracting forward voltage Vd from power supply potential VLD. Here, as an example, it is assumed that the switching signals φf1 to φf8 are maintained at the same potential, and the switching signals φf9 to φf12 are switched simultaneously. Note that the switching signals φf1 to φf12 may be switched individually, or multiple signals may be switched simultaneously as described above. Moreover, all of the switching signals φf1 to φf12 may be switched at the same time.

[0050] At time a, the light-emitting units 22-1 to 22-12 are in the OFF state. The switching signals φf1 to φf12 are at the H level. The signal generating circuit 52 of the driving unit 50 supplies an Off signal to the MOS transistor 51. Therefore, all the driving thyristors S are in the OFF state, and all the light-emitting diodes LED are in the non-emitting state.

[0051] At time b, the switching signals φf9 to φf12 transition from H level to L level. As a result, the gates ([G]) of the drive thyristors S of the light-emitting units 22-9 to 22-12 transition to L level, enabling them to transition from OFF state to ON state. However, because the MOS transistor 51 of the drive unit 50 is OFF state, the drive thyristors S cannot transition to ON state.

[0052] At time c, the signal generating circuit 52 of the drive unit 50 supplies an On signal to the MOS transistor 51. Then, the power supply potential VLD is applied to the series connection of the drive thyristor S and the light-emitting diode LED of each of the light-emitting units 22-9 to 22-12. As a result, the drive thyristor S transitions from the OFF state to the ON state, and the light-emitting diode LED starts to emit light (lights up).

[0053] At time d, the switching signals φf9 to φf12 transition from L level to H level. However, the drive thyristors S of the light-emitting units 22-9 to 22-12 do not transition to the OFF state, and the light-emitting diodes LED continue to emit light.

[0054] At time e, the signal generating circuit 52 of the drive unit 50 supplies an Off signal to the MOS transistor 51. Then, current stops flowing through the series connection between the drive thyristor S and the light-emitting diode LED of each of the light-emitting units 22-9 to 22-12, causing the light-emitting diode LED to stop emitting light (turn off).

[0055] As described above, the light emitting device 4 is controlled. Note that the timing at which the switching signals φf9 to φf12 transition from H level to L level at time b and the timing at which the signal generating circuit 52 in the drive unit 50 supplies an On signal to the MOS transistor 51 at time c may be interchanged. In this case, the light emitting diode LED starts emitting light at the timing at which the switching signals φf9 to φf12 transition from H level to L level. Furthermore, the timing at which the switching signals φf9 to φf12 transition from L level to H level at time d and the timing at which the signal generating circuit 52 in the drive unit 50 supplies an Off signal to the MOS transistor 51 at time e may be interchanged.

[0056] (Structure of light-emitting section 22) The light source 20 is made of a semiconductor material capable of emitting light. For example, the light source 20 is made of a GaAs-based compound semiconductor. 9 As shown in FIG. 1, the light source 20 is configured by a semiconductor layer stack in which a plurality of GaAs-based compound semiconductor layers are stacked on an n-type GaAs substrate 80. The semiconductor layer stack is then separated into a plurality of islands, and the remaining island-like regions are called islands. Etching the semiconductor layer stack into island-like shapes to separate the elements is called mesa etching. The light emitting sections 22 are configured as islands 301 separated from one another. The islands 301 corresponding to the light emitting sections 22-1, 22-2, . . . are denoted as islands 301-1, 301-2, .

[0057] Fig. 8 is an enlarged plan view of the light-emitting section 22. Fig. 8 is an enlarged view of a portion of the light-emitting section 22-12 (island 301-12) in the light source 20 shown in Fig. 4. In the following description, the light-emitting section 22-12 will be referred to as the light-emitting section 22, and the island 301-12 will be referred to as the island 301. The x, y, and z directions are the same as those in Fig. 4.

[0058] FIG. 8 shows a plurality of light-emitting diodes LED. Here, four light-emitting diodes LED1 to LED4 are assigned reference numerals. First, the planar structure of the light-emitting unit 22 will be described, focusing on the light-emitting diode LED1 located at the bottom right of the page. Note that the light-emitting diode LED1 will not be distinguished from the other light-emitting diodes in the following description, and will be referred to as the light-emitting diode LED. The same applies hereinafter.

[0059] In the light-emitting diode LED, the circular portion in the center is a light emission aperture 341 of the light-emitting diode LED. A region 311 (see FIG. 9 described later) of the p anode layer 88 of the drive thyristor S is provided surrounding the light emission aperture 341. A p ohmic electrode 321 is provided on the region 311. Furthermore, six holes (trenches) 342 and six gate electrodes 331 are provided outside the region 311. The gate electrodes 331 are provided on the n gate layer 87 described later. Some of the gate electrodes 331 are connected to the gate electrodes 331 of adjacent light-emitting diodes LED. The n-gate layer 87 is drawn out to the switching unit 23 side, and a gate electrode 332 connected to the signal terminal 24 is provided at one end of the n-gate layer 87. The gate electrode 332 is connected to the signal terminal 24-12 of the switching unit 23 (see FIG. 4). The portion of the n-gate layer 87 drawn out to the switching unit 23 side serves as the wiring 25 (here, this corresponds to the wiring 25-12).

[0060] A light-emitting electrode 72 is provided to cover the light-emitting section 22 except for the light exit aperture 341. The light-emitting electrode 72 is connected to a p-ohmic electrode 321 provided on the region 311 via a through-hole provided in the insulating layer 89 (see FIGS. 9(a) and 9(b) described later). In FIG. 8, the light-emitting electrode 72 is indicated by a dashed line.

[0061] 9 is a cross-sectional view of the light-emitting portion 22. Fig. 9(a) is a cross-sectional view taken along line IXA-IXA in Fig. 8, and Fig. 9(b) is a cross-sectional view taken along line IXB-IXB in Fig. 8. Fig. 9(a) is a cross-sectional view of two adjacent light-emitting diodes LED1 and LED2 sandwiching a gate electrode 331. Fig. 9(b) is a cross-sectional view of two adjacent light-emitting diodes LED3 and LED4 sandwiching a hole 342.

[0062] 9(a), the light-emitting section 22 has an n-type cathode layer (hereinafter referred to as n-cathode layer, and the same applies hereinafter) 81, a light-emitting layer 82, and a p-type anode layer (p-anode layer) 83, which constitute a light-emitting diode LED, stacked on an n-type GaAs substrate 80. In other words, the light-emitting diode LED is configured with the stacked n-cathode layer 81 as the cathode, the light-emitting layer 82 as the light-emitting layer, and the p-anode layer 83 as the anode. Next, a tunnel junction layer 84 is laminated on the p-anode layer 83 . Then, an n-type cathode layer (n-cathode layer) 85, a p-type gate layer (p-gate layer) 86, an n-type gate layer (n-gate layer) 87, and a p-type anode layer (p-anode layer) 88, which constitute the drive thyristor S, are laminated on the tunnel junction layer 84. In other words, the drive thyristor S is configured with the laminated n-cathode layer 85 as the cathode, the p-gate layer 86 as the p-gate, the n-gate layer 87 as the n-gate, and the p-anode layer 88 as the anode.

[0063] The light-emitting diode LED is configured by removing the p-anode layer 88, n-gate layer 87, p-gate layer 86, n-cathode layer 85, and tunnel junction layer 84 of the drive thyristor S stacked on the upper side by etching to expose the p-anode layer 83. That is, light is emitted from the exposed p-anode layer 83. The exposed p-anode layer 83 is the light emission port 341.

[0064] The drive thyristor S is composed of an n-cathode layer 85, p-gate layer 86, n-gate layer 87, and p-anode layer 88 remaining around the light emission port 341 of the light emitting diode LED. On the substrate 80 side of the drive thyristor S, there are a tunnel junction layer 84, and a p-anode layer 83, light emitting layer 82, and n-cathode layer 81 that constitute the light emitting diode LED. In other words, the light emitting diode LED and the drive thyristor S are stacked via the tunnel junction layer 84 and connected in series.

[0065] The tunnel junction layer 84 is provided between the p anode layer 83 of the light emitting diode LED and the n cathode layer 85 of the drive thyristor S. In other words, if the tunnel junction layer 84 is not provided, the p anode layer 83 of the light emitting diode LED and the n cathode layer 85 of the drive thyristor S will be in a reverse bias state, and it will be difficult for current to flow from the n cathode layer 85 of the drive thyristor S to the p anode layer 83 of the light emitting diode LED. The tunnel junction layer 84 is provided between the p anode layer 83 of the light emitting diode LED and the n cathode layer 85 of the drive thyristor S. ++ layer, and the n-type impurity-doped n layer on the side of the n-cathode layer 85 of the driving thyristor S is highly doped ++ In the tunnel junction layer 84, the width of the depletion region is narrow, so that in the reverse bias state, ++ From the conduction band on the layer side to p ++ Electrons tunnel into the valence band on the layer side, which makes it easier for current to flow from the n-cathode layer 85 of the drive thyristor S to the p-anode layer 83 of the light-emitting diode LED.

[0066] Then, a p-ohmic electrode 321 is formed on the p-anode layer 88, making ohmic contact with the p-anode layer 88. The p-ohmic electrode 321 is connected to the light-emitting electrode 72 via a through-hole formed in the insulating layer 89. Furthermore, a portion of p anode layer 88 is removed by etching to expose n gate layer 87, and a gate electrode 331 is formed on the exposed n gate layer 87, making ohmic contact with n gate layer 87. Gate electrode 331 reduces the resistance of the exposed n gate layer 87. The light emitting electrode 72 and the gate electrode 331 are insulated from each other by an insulating layer 89 .

[0067] As shown in FIG. 9(a), between the light emission opening 341 of the light emitting diode LED1 and the light emission opening 341 of the light emitting diode LED2, which are adjacent to each other with the gate electrode 331 in between, the n-cathode layer 81, the light emitting layer 82, the p-anode layer 83, the tunnel junction layer 84, the n-cathode layer 85, the p-gate layer 86, the n-gate layer 87, and the p-anode layer 88, which constitute the light emitting diode LED and the drive thyristor S, are continuous.

[0068] As shown in FIG. 9(b), the light-emitting aperture 341 of the light-emitting diode LED3 and the light-emitting aperture 341 of the light-emitting diode LED4 are adjacent to each other with a hole 342 sandwiched therebetween. The hole 342 is formed by removing the p-anode layer 88, the n-gate layer 87, the p-gate layer 86, the n-cathode layer 85, the tunnel junction layer 84, the p-anode layer 83, the light-emitting layer 82, and the n-cathode layer 81. The current-blocking layer included in the p-anode layer 83 is oxidized through the hole 342, thereby forming a current-blocking portion β through which current does not easily flow. Meanwhile, the portion farther from the hole 342 remains unoxidized. In other words, the unoxidized portion becomes a current-passing portion α through which current passes. A plurality of holes 342 are formed around the light-emitting aperture 341. Therefore, the current-passing portion α is formed in a nearly circular shape. The light-emitting aperture 341 is provided corresponding to the current-passing portion α. Therefore, even if the n-cathode layer 81, p-anode layer 83, and light-emitting layer 82 are provided continuously for the plurality of light-emitting diodes LED in the light-emitting section 22, each light-emitting diode LED emits light at the light exit aperture 341.

[0069] 9(a), the n-cathode layer 85, p-gate layer 86, n-gate layer 87, and p-anode layer 88 that constitute the drive thyristor S are continuous between the light-emitting diodes LED. Therefore, the drive thyristor S operates for each light-emitting section 22. In other words, as shown in FIG. 6, one drive thyristor S is provided for a plurality of light-emitting diodes LED in the light-emitting section 22.

[0070] 8(a) and 8(b), the p anode layer 88, n gate layer 87, p gate layer 86, n cathode layer 85, tunnel junction layer 84, p anode layer 83, light emitting layer 82, and n cathode layer 81 are removed between the light emitting sections 22, i.e., between the islands 301. In other words, the p anode layer 83, light emitting layer 82, and n cathode layer 81 that constitute the light emitting section 22, and the p anode layer 88, n gate layer 87, p gate layer 86, and n cathode layer 85 that constitute the drive thyristor S are discontinuous between the islands 301. Therefore, the light emission of each light emitting section 22 is individually controlled.

[0071] (Configuration of semiconductor layer stack) The semiconductor layer stack includes an n-cathode layer 81, a light-emitting layer 82, a p-anode layer 83, a tunnel junction layer 84, an n-cathode layer 85, a p-gate layer 86, an n-gate layer 87, and a p-anode layer 88 stacked on a substrate 80. The n-cathode layer 81, the light-emitting layer 82, and the p-anode layer 83 are semiconductor layers that constitute the light-emitting diode LED, and the n-cathode layer 85, the p-gate layer 86, the n-gate layer 87, and the p-anode layer 88 are semiconductor layers that constitute the drive thyristor S. The following explains each in order.

[0072] <Substrate 80> Although the substrate 80 will be described as an n-type GaAs substrate, it may also be p-type GaAs or intrinsic (i) GaAs without added impurities. It may also be InP, GaN, InAs, or other semiconductor substrates made of III-V or II-VI materials, or sapphire, Si, or Ge. When the substrate is changed, the material monolithically stacked on the substrate should be a material that approximately matches the lattice constant of the substrate (including strained structures, strain-relief layers, and metamorphic growth). For example, InAs, InAsSb, or GaInAsSb may be used on an InAs substrate; InP or InGaAsP may be used on an InP substrate; GaN, AlGaN, or InGaN may be used on a GaN or sapphire substrate; and Si, SiGe, or GaP may be used on a Si substrate. However, if the substrate 80 is electrically insulating, a separate electrode must be provided to supply a potential to the n-cathode layer 81. Furthermore, when the semiconductor layer stack excluding the substrate 80 is attached to another support substrate and the semiconductor layer stack is provided on the other support substrate, the lattice constant does not need to match that of the support substrate.

[0073] <Semiconductor layers that make up light-emitting diodes (LEDs)> Here, the light emitting diode LED will be described as being a VCSEL. The n-cathode layer 81 constitutes an n-type lower distributed Bragg reflector (DBR) made up of alternating AlGaAs layers with different Al compositions. The light-emitting layer 82 is formed as an active region including a quantum well layer sandwiched between upper and lower spacer layers. The p-anode layer 83 is formed as an upper distributed Bragg reflector made up of alternating AlGaAs layers with different Al compositions. Hereinafter, the distributed Bragg reflector will be referred to as a DBR. The optical output of a single VCSEL is 4mW to 8mW, which is higher than that of other laser diodes.

[0074] The n-type lower DBR constituting the n-cathode layer 81 is made of Al 0.9 Ga 0.1 The lower DBR is constructed as a stack of pairs of As and GaAs layers. Each layer has a thickness of λ / 4n. r (where λ is the oscillation wavelength, n r is the refractive index of the medium), and are alternately stacked 40 times. Silicon (Si), an n-type impurity, is doped as a carrier. The carrier concentration is, for example, 3×10 18 cm -3 is. The lower spacer layer constituting the light-emitting layer 82 is made of undoped Al 0.6 Ga 0.4 The quantum well active layer is an undoped InGaAs quantum well layer and an undoped GaAs barrier layer. The upper spacer layer is an undoped Al 0.6 Ga 0.4 This is the As layer. The p-type upper DBR constituting the p-anode layer 83 is made of p-type Al 0.9 Ga 0.1 The upper DBR is constructed as a stack of pairs of As and GaAs layers. Each layer has a thickness of λ / 4n. r The layers are alternately stacked for 29 periods. Carbon (C), a p-type impurity, is doped as a carrier. The carrier concentration is, for example, 3×10 18 cm -3 A p-type AlAs current confinement layer is provided in the bottom layer of the upper DBR 208 or inside the bottom layer.

[0075] P-type AlAs has a faster oxidation rate than AlGaAs, and the oxidized region is oxidized from the side of the hole 342 toward the inside. When Al is oxidized to form Al2O3, the electrical resistance increases and a current blocking portion β is formed. Note that, instead of AlAs, p-type AlGaAs with a high impurity concentration of Al is used as the current blocking layer. s The current blocking portion β is formed by oxidizing Al to form Al2O3. + ) may be formed by implanting (H + ion implantation).

[0076] <Tunnel junction layer 84> The tunnel junction layer 84 is a p-type semiconductor layer doped with a high concentration of p-type impurities. ++ layer and heavily doped n-type impurities ++ n ++ Layer and p ++ The layer has an impurity concentration of, for example, 1×10 20 / cm 3 The impurity concentration of a normal junction is 10 17 / cm 3 ~10 18 / cm 3 It is a unit. ++ Layer and n ++ Combination with layers (hereinafter referred to as p ++ layer / n ++ It is expressed in layers.) is, for example, p ++ GaAs / n ++ GaInP,p ++ AlGaAs / n ++ GaInP,p ++ GaAs / n ++ GaAs, p ++ AlGaAs / n ++ AlGaAs, p ++ InGaAs / n ++ InGaAs, p ++ GaInAsP / n ++ GaInAsP, p ++ GaAsSb / n ++GaAsSb. The combinations may be interchanged.

[0077] <Semiconductor layer that constitutes the drive thyristor S> The n-cathode layer 85 has an impurity concentration of, for example, 1×10 18 / cm 3 n-type Al 0.9 The Al composition may be changed within the range of 0 to 1. The p-gate layer 86 has an impurity concentration of, for example, 1×10 17 / cm 3 p-type Al 0.9 The Al composition may be changed within the range of 0 to 1. The n-gate layer 87 has an impurity concentration of, for example, 1×10 17 / cm 3 n-type Al 0.9 The Al composition may be changed within the range of 0 to 1. The p-anode layer 88 has an impurity concentration of, for example, 1×10 18 / cm 3 p-type Al 0.9 The Al composition may be changed within the range of 0 to 1.

[0078] <Method of manufacturing the light source 20> The light source 20 is manufactured as follows. An n-cathode layer 81, a light-emitting layer 82, a p-anode layer 83, a tunnel junction layer 84, an n-cathode layer 85, a p-gate layer 86, an n-gate layer 87, and a p-anode layer 88 are laminated in this order on a substrate 80. Next, the p-anode layer 88, the n-gate layer 87, the p-gate layer 86, the n-cathode layer 85, the tunnel junction layer 84, the p-anode layer 83, the light-emitting layer 82, and the n-cathode layer 81 are etched to form portions that separate the light-emitting section 22 and holes 342.

[0079] Then, in an oxidizing atmosphere, the current confinement layer in the p anode layer 83 is oxidized from the side surface of the hole 342 to form the current blocking portion β.

[0080] Furthermore, a portion of the p anode layer 88 is etched to expose the surface of the n gate layer 87. Then, a p ohmic electrode 321 is formed on the p anode layer 88, and a gate electrode 331 is formed on the n gate layer 87 in ohmic contact with the n gate layer 87. The p ohmic electrode 321 is made of, for example, Au containing Zn (AuZn) that makes ohmic contact with p-type AlGaAs. The gate electrode 331 is made of, for example, Au containing Ge (AuGe) that makes ohmic contact with n-type AlGaAs.

[0081] next, all An insulating layer 89 is formed on the surface. Then, the insulating layer 89, p anode layer 88, n gate layer 87, p gate layer 86, n cathode layer 85, and tunnel junction layer 84 are etched to form a light emitting aperture 341. The insulating layer 89 is made of, for example, SiO2 or SiN. Then, a through hole is formed in the insulating layer 89 in the area of ​​the p ohmic electrode 321, and the light-emitting electrode 72 is formed. At the same time as the light-emitting electrode 72, the signal terminal 24 of the switching unit 23 and a wiring that connects the signal terminal 24 and the n-gate layer 87 are formed.

[0082] The light source 20 may be manufactured by switching the above steps. For example, the light exit aperture 341 may be formed before forming the insulating layer 89. In this case, the light exit aperture 341 is covered and protected by the insulating layer 89. In this case, the insulating layer 89 is made of a material that transmits light from the light-emitting diode LED.

[0083] As described above, if the light emitting diode LED and the drive thyristor S are stacked, the light emission of the light emitting diode LED can be controlled by supplying a switching signal φf to the drive thyristor S. In other words, it is easier to control the light emission of the light emitting diode LED compared to when the light emitting diode LED and the drive thyristor S are not stacked.

[0084] (Modification of Light Emitting Device 4) 5 to which the present embodiment is applied, the light emitting sections 22 are arranged in a matrix in the light emitting section 21 of the light source 20. However, the light emitting sections 22 do not necessarily have to be arranged in a matrix.

[0085] 10 is a diagram showing a light emitting device 4A which is a modified example of the light emitting device 4 to which the present embodiment is applied. Here, a light source 20A is different from the light source 20 of the light emitting device 4. Other parts are the same as those of the light source 20 of the light source 20A. The same parts as those of the light source 20 will be described using the same reference numerals.

[0086] The light source 20A includes four light-emitting units 22. The four light-emitting units 22 are not arranged in a matrix. In this way, the multiple light-emitting units 22 may be arranged in an arrangement other than a matrix. The switching unit 23 is arranged on the opposite side of the driving unit 50. This makes the distance between the driving unit 50 and the light-emitting units 22 shorter than when the switching unit 23 is provided between the driving unit 50 and the light-emitting units 22. This reduces the inductance between the driving unit 50 and the light-emitting units 22 in the light source 20 in the light-emitting device 4A, shortening the rise time of the light pulse.

[0087] 11 is a diagram showing a light emitting device 4B, which is a modified example of the light emitting device 4 to which the present embodiment is applied. Here, a light source 20B is different from the light source 20 of the light emitting device 4. Other parts are the same as those of the light source 20 of the light source 20B. The same reference numerals are used to denote the same parts as those of the light source 20 of the light source 20B.

[0088] The light-emitting unit 22 in the light source 20 of the light-emitting device 4 (see FIG. 4) and the light-emitting unit 22 in the light source 20A of the light-emitting device 4A (see FIG. 10) to which this embodiment is applied have a rectangular planar shape. In contrast, the light-emitting unit 22 in the light source 20B of the light-emitting device 4B shown in FIG. 11 has a rounded rectangular planar shape. As such, the planar shape of the light-emitting unit 22 may be a shape other than a rectangle, such as a circle, an ellipse, or a polygon. The switching unit 23 is disposed on the opposite side of the driving unit 50. This shortens the distance between the driving unit 50 and the light-emitting unit 22 compared to when the switching unit 23 is disposed between the driving unit 50 and the light-emitting unit 22. This reduces the inductance between the driving unit 50 and the light-emitting unit 22 in the light source 20 in the light-emitting device 4B, shortening the rise time of the light pulse.

[0089] 12 is an equivalent circuit diagram showing a light emitting device 4C, which is a modified example of the light emitting device 4 to which the present embodiment is applied. Here, a switching unit 23C is different from the switching unit 23 of the light emitting device 4. Other parts are the same as those of the light emitting device 4. The switching unit 23 of the light emitting device 4 is composed of signal terminals 24 provided corresponding to the light emitting units 22. The switching unit 23C of the light emitting device 4C is composed of switching elements 24C. The switching signal φf is supplied to the drive thyristor S via the switching elements 24C. In FIG. 12, the switching elements 24C corresponding to the light emitting units 22-1, 22-2, and 22-3 are denoted as switching elements 24C-1, 24C-2, and 24C-3. In this way, the switching unit 23C may be configured with a switching element 24C.

[0090] 13 is an equivalent circuit diagram showing a light emitting device 4D, which is a modified example of the light emitting device 4 to which the present embodiment is applied. Here, a switching unit 23D is different from the switching unit 23 of the light emitting device 4. Other parts are the same as those of the light emitting device 4. The switching unit 23D includes the switching element 24C of the light-emitting device 4C, as well as a transfer circuit 28 that sequentially transfers the ON state of the switching element 24C. That is, the transfer circuit 28 causes the switching element 24C-1 to transition from the OFF state to the ON state and then transition back to the OFF state, and then causes the switching element 24C-2 to transition from the OFF state to the ON state. In this manner, the transfer circuit 28 sequentially transfers the ON state. This allows the multiple light-emitting units 22 to emit light sequentially. That is, there is no need to individually control the light emission of the light-emitting units 22; the light emission of the light-emitting units 22 is controlled by supplying a start signal to the transfer circuit 28 to start light emission. Such a transfer circuit 28 is, for example, a shift register.

[0091] In this embodiment, a light emitting diode LED, which is an example of a light emitting element, is provided on a substrate 80, and a drive thyristor S is laminated on the light emitting diode LED. The drive thyristor S may also be provided on the substrate 80, and the light emitting diode LED may be laminated on the drive thyristor S. In addition, although the present embodiment uses an n-type substrate 80, a p-type substrate may be used to configure the light source 20 with the opposite polarity. In this case, the light emitting diode LED may be provided on the substrate and the drive thyristor S may be stacked on the light emitting diode LED, or the drive thyristor S may be provided on the substrate 80 and the drive thyristor S may be stacked on the drive thyristor S.

[0092] In this embodiment, the light-emitting units 22 are configured so that the light-emitting elements (light-emitting diodes LED in this embodiment) of the same light-emitting unit 22 are adjacent to each other, which facilitates the configuration of the light-emitting units 22. However, the light-emitting elements do not need to be arranged in a cluster, and light-emitting elements connected to the same signal terminal 24 of the switching unit 23 may be regarded as one light-emitting unit 22.

[0093] In the present embodiment, an example has been shown in which the light emitting device 4 is used together with the 3D sensor 5, but the present invention is not limited to this. The present invention may also be applied to a light emitting device used for optical transmission, in which case it may be combined with an optical transmission path, and the light switched by the switching unit may be input to the same optical transmission path or different optical transmission paths. [Explanation of symbols]

[0094] 1...information processing device, 2...user interface (UI) unit, 3...optical device, 4, 4A, 4B, 4C, 4D...light-emitting device, 5...three-dimensional sensor (3D sensor), 8...measurement control unit, 8A...3D shape identification unit, 9...system control unit, 9A...recognition processing unit, 10...wiring board, 20, 20A, 20B...light source, 21...light emitting unit, 22, 22-1 to 22-12...light-emitting unit, 23, 23C, 23D...switching unit, 24, 24-1 to 24-12...signal terminal, 24C, 24C-1 to 24C-3...switching element, 25...wiring, 28...transfer circuit, 30...light diffusing member, 40...holding unit, 50...driving unit, 51...MOS transistor, 52... Signal generating circuit, 71...reference potential wiring, 72...light-emitting electrode, 72A, 72B...pad portion, 80...n-type substrate, 81...n-type cathode layer (n-cathode layer), 82...light-emitting layer, 83...p-type anode layer (p-anode layer), 84...tunnel junction layer, 85...n-type cathode layer (n-cathode layer), 86...p-type gate layer (p-gate layer), 87...n-type gate layer (n-gate layer), 88...p-type anode layer (p-anode layer), 89...insulating layer, 90...back electrode, 100...irradiation area, φf, φf1 to φf12...switching signal, LED...light-emitting diode, S...drive thyristor, VLD...power supply potential, Vd...forward voltage (diffusion potential)

Claims

1. A wiring board and A plurality of light emitting units; a driving unit that supplies a current to the light emitting unit to drive the light emitting unit; a switching unit that switches between the lights emitted by the plurality of light-emitting units; a light-emitting electrode to which a power supply potential is applied, the plurality of light-emitting units, the switching unit, and the driving unit are arranged on the wiring board, and the switching unit is provided on the wiring board on an opposite side of the plurality of light-emitting units from the driving unit; The light-emitting electrode is an electrode provided in common to the plurality of light-emitting sections, and a pad section is provided on the outside of the plurality of light-emitting sections at a position on the wiring board different from a position where the drive section and a position where the switching section are provided, and the power supply potential is applied via the pad section. Light-emitting device.

2. A wiring board and A plurality of light emitting units; a driving unit that supplies a current to the light emitting unit to drive the light emitting unit; a switching unit that switches between the lights emitted by the plurality of light-emitting units; a light-emitting electrode to which a power supply potential is applied, the plurality of light-emitting units, the switching unit, and the driving unit are arranged on the wiring board, and the switching unit is provided on the wiring board on an opposite side of the plurality of light-emitting units from the driving unit; the light-emitting electrode is an electrode provided in common to the plurality of light-emitting portions, has a pad portion on the outer side of the plurality of light-emitting portions, and is applied with the power supply potential via the pad portion; the plurality of light-emitting portions are surrounded by first and second edges facing each other, and third and fourth edges connecting the first and second edges and facing each other; The driving section, the switching section, and the pad section of the light-emitting electrode are provided on different edge sides. Light-emitting device.

3. The light emitting device according to claim 2 , wherein the driving section and the switching section are provided on the first edge side and the second edge side that face each other.

4. The light emitting device according to claim 3 , wherein the light emitting electrode has pad portions on both the third edge side and the fourth edge side.

5. wiring for connecting each of the plurality of light-emitting units to the switching unit; The light emitting device according to claim 1 , wherein the wiring is provided outside the light emitting portion and along the light emitting portion.

6. The light emitting device according to claim 1 , wherein the switching unit includes a switching element.

7. The light emitting device according to claim 6 , wherein the switching section sequentially transfers the on states of the switching elements provided for the light emitting sections.

8. 2. The light emitting device according to claim 1, wherein the light emitting portion comprises a light emitting diode and a thyristor that is stacked on the light emitting diode and that causes the light emitting diode to emit light when turned on.

9. 9. The light emitting device according to claim 8, wherein the light emitting diode is a vertical cavity surface emitting laser.

10. A light emitting device according to any one of claims 1 to 9; a three-dimensional sensor that receives reflected light from an object to be measured that is irradiated with light emitted from the light emitting device; A measuring device comprising:

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