Light-emitting device

Abstract

Provided is a light-emitting device that can highly-accurately monitor light output of a light-emitting element.　The present technology provides a light-emitting device comprising a surface light-emitting element and a light-receiving element. The surface light-emitting element emits light in a prescribed direction. The light-receiving element receives monitor light leaking in at least one direction different from the prescribed direction, and has a smaller size than the surface light-emitting element. The present technology also provides a light-emitting device comprising: a difference detection unit that detects the difference between a reference value and an input / output signal corresponding to each of a plurality of light-emitting elements; an event generation unit that generates an event on the basis of a result of comparison between said difference and a prescribed threshold value; and an output unit that outputs event information including identification information for identifying a light-emitting element that is a source of the generated event.

Description

Light-emitting device

[0001] The technology disclosed herein (hereinafter also referred to as "this technology") relates to a light-emitting device.

[0002] In light-emitting devices, the technology of combining light-emitting elements (e.g., VCSELs, PCSELs, etc.) and photodetectors (e.g., photodiodes) is widely used in optical communications and sensor fields. In particular, a technology is known in which light-emitting elements are arranged in an array, and the photodetector monitors the light output of each light-emitting element. This makes it possible to efficiently control multiple light sources and obtain a stable light output.

[0003] One method for monitoring light-emitting elements involves integrating a photodetector with the substrate of the light-emitting element to directly receive leaked light. This type of structure is used for controlling and stabilizing the amount of emitted light.

[0004] For example, Patent Document 1 describes a technology relating to a vertical-cavity surface-emitting laser with an integrated photodiode.

[0005] Special Publication No. 2011-520280

[0006] However, with conventional technology, the increased size of the photodetector and the amount of data processing lead to the effects of ambient light and increased complexity of the overall system, negatively impacting the accuracy of monitoring.

[0007] Therefore, the primary objective of this technology is to provide a light-emitting device capable of highly accurate monitoring of the light output of a light-emitting element.

[0008] This technology provides a light-emitting device comprising a surface light-emitting element and a light-receiving element, wherein the surface light-emitting element emits light in a predetermined direction, and the light-receiving element receives monitor light leaking in at least one direction different from the predetermined direction, and the device is smaller in size than the surface light-emitting element. The light-emitting device further comprises a substrate, wherein the substrate, the surface light-emitting element, and the light-receiving element are arranged in this order, wherein the surface light-emitting element emits light in the direction of the substrate, and the light-receiving element receives the monitor light leaking in the direction opposite to the direction of the substrate. The light-receiving elements may be arranged in an array, and a plurality of monitor lights leaking in at least one direction different from the direction of light emission, corresponding to a plurality of light emission points, may be individually monitored. The surface light-emitting element is a photonic crystal laser, and the light-receiving elements may be arranged to correspond to the light emission points in order to monitor a plurality of monitor lights leaking from a plurality of light emission points of the photonic crystal laser in at least one direction different from the direction of light emission. The photodetector may be arranged in a direction perpendicular to the direction of light emission and receive monitor light leaking in the direction perpendicular. The photodetector may be arranged in the opposite direction and perpendicular to the direction of light emission and receive monitor light leaking in the opposite direction and perpendicular. The device further includes a laser driver, and the photodetector formed on the laser driver may receive monitor light leaking through an opening provided on the laser driver side of the surface light-emitting element. The photodetector may be a PIN type photodiode or an avalanche photodiode. A transimpedance amplifier may be added to the photodetector, and the transimpedance amplifier may convert the current signal generated by the photodetector into a voltage signal. The surface light-emitting element may be a vertical-cavity surface-emitting laser. Furthermore, this technology provides a light-emitting device comprising: a difference detection unit that detects the difference between the input / output signals corresponding to each of a plurality of light-emitting elements and a reference value; an event generation unit that generates an event based on the comparison result of the difference and a predetermined threshold; and an output unit that outputs event information including identification information that identifies the light-emitting element that is the source of the generated event.The identification information may include at least one of the following: coordinates for identifying the light-emitting element that is the source of the event, the time of the event, and the polarity of the event. The difference detection unit may have a configuration that asynchronously detects the difference between the input / output signal and a reference value. The amplifier provided in the difference detection unit may have a configuration that increases the gain when the difference between the input / output signal and the reference value is small, and decreases the gain when the difference is large. The device may further include an arbitration circuit for arbitrating events associated with each of the multiple light-emitting elements in the order in which they occur and outputting them sequentially. The light-emitting device may further include a photodetector that receives the light emitted from the light-emitting element, and the output unit may output the event information based on the signal from the photodetector and the event generated by the event generation unit. The light-emitting device may further include a control unit that controls the drive current or temperature of the light-emitting element based on the event information. The light-emitting device may further include a laser driver, and the light-emitting element, the laser driver, and the difference detection unit may be stacked in this order and electrically connected to each other. The light-emitting device further includes a light-receiving element that receives light emitted from the light-emitting element, and the output unit may output event information based on the signal from the light-receiving element and the event generated by the event generation unit. The light-emitting element may have a back-side emission structure that emits light in the direction of the substrate.

[0009] Figure 1A is a schematic cross-sectional view showing an example configuration of a light-emitting device 1001 according to a comparative example of the present technology. Figure 1B is a schematic plan view of the light-emitting device 1001 shown in Figure 1A. The explanation will be given with reference to Figure 2. Figure 2A is a schematic cross-sectional view showing an example configuration of a light-emitting device 1000 according to one embodiment of the present technology. Figure 2B is a schematic plan view of the light-emitting device 1000 shown in Figure 2A. Figure 3A is a schematic cross-sectional view showing an example configuration of a light-emitting device 1000 according to one embodiment of the present technology. Figure 3B is a schematic plan view of the light-emitting device 1000 shown in Figure 3A. A schematic cross-sectional view showing an example of a manufacturing method of the light-emitting device 1000 according to one embodiment of the present technology. Figure 5A is a schematic cross-sectional view showing an example configuration of a light-emitting device 1000 according to one embodiment of the present technology. Figure 5B is a schematic plan view of the light-emitting device 1000 shown in Figure 5A. Figure 6A is a schematic cross-sectional view showing an example configuration of a light-emitting device 1000 according to one embodiment of the present technology. Figure 6B is a schematic plan view of the light-emitting device 1000 shown in Figure 6A. Figure 7A is a schematic cross-sectional view showing an example of the configuration of a light-emitting device 1000 according to one embodiment of this technology. Figure 7B is a schematic plan view of the light-emitting device 1000 shown in Figure 7A. Figure 8A is a schematic cross-sectional view showing an example of the configuration of a light-emitting device 1000 according to one embodiment of this technology. Figure 8B is a schematic plan view of the light-emitting device 1000 shown in Figure 8A. A schematic cross-sectional view showing an example of the configuration of a light-emitting device 1000 according to one embodiment of this technology. A flowchart showing an example of a method for manufacturing a light-emitting device according to one embodiment of this technology. A schematic cross-sectional view showing an example of a method for manufacturing a light-emitting device 10 This is a schematic cross-sectional view showing an example of a manufacturing method for a light-emitting device 1000 according to one embodiment of this technology.This is a schematic cross-sectional view showing an example of a manufacturing method for a light-emitting device 1000 according to one embodiment of this technology. This is a schematic cross-sectional view showing an example of a manufacturing method for a light-emitting device 1000 according to one embodiment of this technology. This is a schematic cross-sectional view showing an example of a manufacturing method for a light-emitting device 1000 according to one embodiment of this technology. This is a block diagram showing an example of the configuration of a light-emitting device 1000 according to one embodiment of this technology. This is a graph showing an example of the operation and threshold of a light-emitting device 1000 according to one embodiment of this technology. This is a graph showing an example of the operation and threshold of a light-emitting device 1000 according to one embodiment of this technology. This is a graph showing an example of the operation and threshold of a light-emitting device 1000 according to one embodiment of this technology. This is a circuit diagram showing a part of the configuration of a light-emitting device 1000 according to one embodiment of this technology. This is a block diagram showing an example of the configuration of a light-emitting device 1000 according to one embodiment of this technology. This is a graph showing the operation of an amplifier according to one embodiment of this technology. This is a circuit diagram showing a part of the configuration of a light-emitting device 1000 according to one embodiment of this technology. This is a circuit diagram showing a part of the configuration of a light-emitting device 1000 according to one embodiment of this technology. This is a circuit diagram showing a part of the configuration of a light-emitting device 1000 according to one embodiment of this technology. This is a schematic cross-sectional view showing an example of the configuration of a light-emitting device 1000 according to one embodiment of this technology. This is a schematic cross-sectional view showing an example of the configuration of a light-emitting device 1000 according to one embodiment of this technology. This is a circuit diagram showing a partial configuration of a light-emitting device 1000 according to one embodiment of this technology. This is a flowchart showing an example of a sensing method for a light-emitting element according to one embodiment of this technology. This is a block diagram showing an example configuration of a distance measuring device 5000 according to one embodiment of this technology. This is a block diagram showing an example of a schematic configuration of a vehicle control system. This is an explanatory diagram showing an example of the installation position of the imaging unit.

[0010] Hereinafter, preferred embodiments for implementing this technology will be described with reference to the drawings. The embodiments described below are merely examples of typical embodiments of this technology and do not limit the scope of this technology. Furthermore, this technology can be implemented by combining any of the following embodiments and their modifications.

[0011] In the following description of embodiments, configurations may be described using terms with "approximately" attached, such as "approximately parallel" and "approximately orthogonal." For example, "approximately parallel" means not only that they are perfectly parallel, but also that they are substantially parallel, that is, that is, they are deviated from a perfectly parallel state by, for example, a few percent. The same applies to other terms with "approximately." Also, each figure is a schematic diagram and is not necessarily a strictly accurate representation. The scale of the drawings is exaggerated to make the technical features easier to understand. Therefore, it should be noted that the scale of the drawings and the scale of the actual device are not necessarily the same.

[0012] Unless otherwise specified, in drawings, "up" means the upper direction or upper side in the drawing, "down" means the lower direction or lower side in the drawing, "left" means the left direction or left side in the drawing, and "right" means the right direction or right side in the drawing. In addition, in drawings, the same or equivalent elements or components are denoted by the same reference numeral, and redundant explanations are omitted.

[0013] The embodiments described below represent typical embodiments of the Technology and should not be interpreted as narrowing the scope of the Technology. The effects described herein are illustrative and not limiting, and other effects may also exist.

[0014] The explanation will proceed in the following order: 1. First Embodiment of the Technology (Example 1 of a Light-Emitting Device) (1) Comparative Example (2) Example 1 (3) Example 2 (4) Example 3 (5) Example 4 (6) Example 5 (7) Example 6 (8) Example 7 2. Second Embodiment of the Technology (Example of a Method for Manufacturing a Light-Emitting Device) 3. Third Embodiment of the Technology (Example 2 of a Light-Emitting Device) (1) Monitoring of the Light-Emitting Device (2) Overview of this Embodiment (3) Operation and Threshold Setting (4) Circuit (5) Effects (6) Example 1 (7) Example 2 (8) Example 3 (9) Example 4 (10) Example 5 (11) Example 6 4. Fourth Embodiment of the Technology (Example of a Sensing Method for a Light-Emitting Device) 5. Fifth Embodiment of the Technology (Example of a Distance Measuring Device) 6. Sixth Embodiment of the Technology (Example of an Electronic Device)

[0015] [1. First Embodiment of the Technology (Example 1 of Light-Emitting Device)] [(1) Comparative Example] In order to explain the contents of the Technology, a comparative example of the Technology will be described with reference to Figure 1. Figure 1A is a schematic cross-sectional view showing an example of the configuration of a light-emitting device 1001 according to a comparative example of the Technology. Figure 1B is a schematic plan view of the light-emitting device 1001 shown in Figure 1A.

[0016] As shown in Figure 1, the light-emitting device 1001 is constructed by stacking a light-receiving element 300 and a surface-emitting element 100 in that order on a substrate 101.

[0017] The surface light-emitting element 100 is a light-emitting element that emits light in the vertical direction (upward direction in the figure). The surface light-emitting element 100 comprises a DBR (Distributed Bragg Reflector) layer 107 and an active layer 104.

[0018] The DBR layer 107 is a multilayer reflective structure positioned on the upper and lower parts of the surface light-emitting element 100, achieving high reflectivity and improving the efficiency of optical resonance. The DBR layer 107 is formed by alternately stacking high refractive index layers and low refractive index layers, and has high reflectivity in the required wavelength range.

[0019] The active layer 104 plays a role in generating light through electric current injection. The active layer 104 consists of a quantum well structure or a multiple quantum well structure. The light generated in the active layer 104 resonates in the upper and lower DBR layers 107 and is emitted as emitted light L1.

[0020] The first cathode electrode 109c connected to the surface light-emitting element 100 has a structure that forms a current-carrying path for current injection.

[0021] The common electrode 109e is an electrode that is connected in common to the surface light-emitting element 100 and the light-receiving element 300.

[0022] The light-receiving element 300 detects the monitor light L2 leaking downward from the surface light-emitting element 100. The light-receiving element 300 is, for example, a PIN-type photodiode consisting of a p-layer 301, an i-layer 302, and an n-layer 303, and detects the leaked light and converts it into an electrical signal.

[0023] The second cathode electrode 109d connected to the photodetector 300 has the role of transmitting the signal detected by the photodetector 300 to an external circuit.

[0024] As shown in the figure, ambient light L3 incident from the right may adversely affect the light-receiving element 300. Because the size of the light-receiving element 300 is larger than that of the surface-emitting element 100, it is difficult to distinguish between the monitor light L2 and the ambient light L3, and in some cases the light from the surface-emitting element 100 may not be accurately detected.

[0025] Furthermore, when the surface light-emitting elements 100 are arranged in an array, the size of the light-receiving elements 300 is larger than that of the surface light-emitting elements 100, making it difficult to individually monitor the light intensity of each surface light-emitting element 100.

[0026] This technology solves these problems by miniaturizing the light-receiving element compared to a surface-emitting element and employing a structure that can detect only the monitoring light.

[0027] [(2) Example 1] This technology provides a light-emitting device comprising a surface light-emitting element and a light-receiving element, wherein the surface light-emitting element emits light in a predetermined direction, and the light-receiving element receives monitor light leaking in at least one direction different from the predetermined direction, and is smaller in size than the surface light-emitting element.

[0028] The light-emitting device relating to this technology will be described with reference to Figure 2. Figure 2A is a schematic cross-sectional view showing an example of the configuration of a light-emitting device 1000 according to one embodiment of this technology. Figure 2B is a schematic plan view of the light-emitting device 1000 shown in Figure 2A.

[0029] As shown in Figure 2, the light-emitting device 1000 comprises a surface light-emitting element 100 and a light-receiving element 300. In this configuration example, the surface light-emitting element 100 and the light-receiving element 300 are stacked on top of each other to constitute the light-emitting device 1000.

[0030] The surface light-emitting element 100 has the function of emitting light L1 having a predetermined wavelength and beam shape in a predetermined direction. The emitted light L1 can be used in a variety of applications that require high optical properties, and is used in fields such as the following.

[0031] The surface-emitting element 100 is used as a signal transmission source in optical fiber networks where high-density and high-speed data communication is required. The high efficiency and miniaturization of the surface-emitting element 100 provide excellent performance in optical transceivers and data center communications.

[0032] Furthermore, the surface light-emitting element 100 is used in mobile devices and industrial sensors for distance measurement, face recognition, object detection, and other applications. In particular, 3D sensing technology requires a high-power and precise light source, and the high directivity of the surface light-emitting element 100 is highly effective.

[0033] Furthermore, because the surface light-emitting element 100 has high integration capabilities in the manufacturing process, a large number of light-emitting elements can be arranged on a single substrate, and applications as a multi-beam light source and optical switching device are expected.

[0034] The surface-emitting element 100 is constructed using semiconductor materials such as aluminum gallium arsenide (AlGaAs) or gallium arsenide (GaAs), and high-quality optical properties can be obtained by using epitaxial growth technology. As a result, the surface-emitting element 100 is provided as a long-life and highly reliable optical device.

[0035] In this embodiment, the surface light-emitting element 100 is a Vertical-Cavity Surface-Emitting Laser (VCSEL). By employing a VCSEL, it becomes possible to emit high-quality laser light in the vertical direction. VCSELs have a structure that is highly efficient, low power consumption, and suitable for multi-point arrays, exhibiting excellent performance in optical communication and precision measurement fields. Furthermore, due to its structure, VCSELs can be arranged at high density on a substrate, making them particularly suitable for realizing compact and highly integrated optical devices. In addition, VCSELs have stable wavelength characteristics and can suppress wavelength shifts due to changes in temperature and driving conditions, thus enabling highly accurate optical output control.

[0036] Furthermore, the surface light-emitting element 100 may have a configuration that operates in single mode in lateral mode. Single-mode operation improves the output beam quality of the light and maintains high spatial coherence.

[0037] The light-receiving element 300 is, for example, a photodiode and is used to monitor the characteristics of the emitted light L1. In the present embodiment, the light-receiving element 300 is designed to be smaller than the surface-emitting element 100 and is arranged to receive the monitor light L2 leaking in at least one direction different from the emission direction of the emitted light L1 emitted from the surface-emitting element 100.

[0038] Specifically, in this configuration, the light-receiving element 300 is arranged at a position where it receives the monitor light L2 leaking in the direction opposite to the emission direction of the emitted light L1. For this reason, the light-receiving element 300 may be integrated with the surface-emitting element 100. Thereby, an optical monitoring function can be effectively realized and the configuration of the entire system can be simplified.

[0039] Also, the size and arrangement of the light-receiving element 300 are optimized to maximize the incident efficiency of the monitor light L2. Thereby, the reliability of the monitoring signal is improved, and miniaturization and high integration of the entire device configuration are enabled.

[0040] The first cathode electrode 109c connected to the surface-emitting element 100 is arranged on the side walls of the surface-emitting element 100 and the light-receiving element 300, and efficiently supplies current to these elements. By forming the electrode on the side wall, the through electrodes and wire bonding that were conventionally required are made unnecessary, and miniaturization of the chip is realized.

[0041] The second cathode electrode 109d connected to the light-receiving element 300 has a role of transmitting the signal detected by the light-receiving element 300 to an external circuit.

[0042] The common electrode 109e is an electrode commonly connected to the surface-emitting element 100 and the light-receiving element 300. This common electrode 109e functions as a current supply path for supplying current to the surface-emitting element 100 and the light-receiving element 300, and plays a role of stabilizing the operation of each element.

[0043] The common electrode 109e also functions as an element to achieve miniaturization of the entire chip. Specifically, by arranging the common electrode 109e on the side wall of the light-receiving element 300, the mounting space can be efficiently used, enabling a compact device design.

[0044] An insulating layer 15 for maintaining electrical insulation is arranged between each electrode. With this structure, interference between the electrodes of the surface light-emitting element 100 and the light-receiving element 300 is prevented, enabling stable operation.

[0045] In this structure, by adopting a structure in which the size of the light-receiving element 300 is made smaller than that of the surface light-emitting element 100 and only the monitor light L2 is received, the following effects are produced.

[0046] According to this technology, by optimizing the size of the light-receiving element 300, it is possible to prevent the mixing of external disturbance light and efficiently detect only the monitor light L2 leaking from the surface light-emitting element 100. As a result, the light output of the surface light-emitting element 100 can be monitored with high precision, and the optical power of the emitted light can be accurately controlled. Thereby, high reliability and stability required in optical communication and sensor applications can be realized.

[0047] Further, by adopting a structure in which electrodes are formed on the side wall, through electrodes and wire bonding become unnecessary. This structure simplifies the manufacturing process of the device, not only contributes to cost reduction, but also enables reduction of the overall chip size. Thereby, an advantageous structure is provided for applications that require high-density mounting and miniaturization.

[0048] Furthermore, by optimizing the size of the light-receiving element 300, it becomes possible to arrange the surface light-emitting element 100 and the light-receiving element 300 in an array. With this array structure, a plurality of surface light-emitting elements 100 and light-receiving elements 300 can be efficiently arranged on one substrate, improving the design freedom of the entire optical device. Also, this structure promotes improvement of throughput and high functionality in optical communication systems and sensing systems.

[0049] The effects described herein are not necessarily limited and may be any of the effects described in this disclosure. Furthermore, the effects described herein will also occur in other embodiments and examples described later.

[0050] In the light-emitting device 1000 according to this technology, the light-receiving element 300 is preferably configured as a PIN-type photodiode. Due to its structure, a PIN-type photodiode has high-frequency response characteristics and can operate at high speed.

[0051] Specifically, PIN-type photodiodes can efficiently receive optical signals, including short-pulse light and modulated signals, and accurately convert them into electrical signals. This enables high-precision optical monitoring and data measurement using short-pulse light and modulated signals. Furthermore, due to their high-frequency response performance, PIN-type photodiodes can accurately detect short-duration optical signal fluctuations, enabling real-time monitoring.

[0052] Furthermore, PIN-type photodiodes can measure short-pulse light and high-frequency modulated signals, contributing to precise optical power control and feedback control.

[0053] In the light-emitting device 1000 related to this technology, an avalanche photodiode (APD) can also be used as the light-receiving element 300. Avalanche photodiodes have the characteristic of achieving highly sensitive light detection by utilizing the light amplification effect.

[0054] Specifically, APDs can internally amplify the carriers (electrons and holes) generated when a photon is incident on them. This amplification effect makes it possible to detect minute optical signals as electrical signals with high precision. Therefore, APDs are particularly useful in high-sensitivity applications where it is necessary to detect weak optical signals.

[0055] In the light-emitting device 1000 according to this technology, a configuration in which a transimpedance amplifier (TIA) is added to the photodetector 300 can also be adopted. This TIA has the function of converting the current signal generated by the photodetector 300 into a voltage signal, enabling highly accurate and efficient signal processing.

[0056] Light incident on the photodetector 300 is output as a current signal. This current signal is converted into a voltage signal by the TIA and input to a subsequent signal processing circuit. By converting the current signal to a voltage signal, the TIA effectively amplifies the output signal of the photodetector 300, enabling high-precision processing of weak light signals. Furthermore, the configuration in which the TIA directly converts the current signal improves the speed of signal processing, enabling real-time monitoring and feedback control.

[0057] The light-emitting device 1000 based on this technology can be widely applied to various fields such as optical communication, sensors, and precision measuring devices. The light-emitting device 1000 constructed based on this technology achieves both high-precision monitoring capabilities and miniaturization. This feature enables the construction of high-speed and stable optical communication systems, improvement of sensor systems that detect minute changes, and the development of high-precision and compact measuring devices.

[0058] The above description of the light-emitting device according to this embodiment can be applied to other embodiments and models of this technology, unless there are any particular technical inconsistencies.

[0059] [(3) Example 2] Another embodiment of the light-emitting device according to the present technology will be described with reference to Figure 3. Figure 3A is a schematic cross-sectional view showing an example of the configuration of a light-emitting device 1000 according to one embodiment of the present technology. Figure 3B is a schematic plan view of the light-emitting device 1000 shown in Figure 3A.

[0060] The light-emitting device 1000 shown in Figure 3 differs from that of Embodiment 1 in that it further includes a substrate 101. The substrate 101, the surface light-emitting element 100, and the light-receiving element 300 are arranged in this order. The surface light-emitting element 100 emits light L1 in the direction of the substrate 101. The light-receiving element 300 receives monitor light L2 that leaks in the opposite direction to the substrate 101.

[0061] In this configuration, a "back-side emission structure" is employed, which directs the emitted light L1 from the surface light-emitting element 100 toward the substrate 101 side (back side). This back-side emission structure improves the design flexibility of the entire light-emitting device, making it possible to achieve miniaturization and high efficiency.

[0062] The substrate 101 is made of a compound semiconductor material (e.g., GaAs). This compound semiconductor material has the property of efficiently transmitting near-infrared wavelength light emitted from the surface light-emitting element 100. On the other hand, because the compound semiconductor material has low transmittance of visible light, it has the effect of reducing the influence of ambient light from visible light coming from the outside.

[0063] This improves the signal quality of the monitor light detected by the photodetector 300, making it possible to create an environment in which the light output of the surface light-emitting element 100 can be monitored with high precision. Furthermore, by utilizing the transmission characteristics of the substrate 101, the structure of the surface light-emitting element 100 and the photodetector 300 can be further optimized, enabling the realization of a high-performance and compact optical device.

[0064] The manufacturing method of the light-emitting device 1000 according to this embodiment will be described with reference to Figure 4. Figure 4 is a schematic cross-sectional view showing an example of a manufacturing method of the light-emitting device 1000 according to one embodiment of this technology.

[0065] As shown in Figure 4, first, the substrate 101 is placed. Next, a surface light-emitting element 100 is formed on the substrate 101, and then a light-receiving element 300 is placed on the surface light-emitting element 100. This structure makes it possible to form the light-receiving element 300 smaller than the surface light-emitting element 100.

[0066] The above description of the light-emitting device according to this embodiment can be applied to other embodiments and models of this technology, unless there are any particular technical inconsistencies.

[0067] [(4) Example 3] Another embodiment of the light-emitting device according to the present technology will be described with reference to Figure 5. Figure 5A is a schematic cross-sectional view showing an example of the configuration of a light-emitting device 1000 according to one embodiment of the present technology. Figure 5B is a schematic plan view of the light-emitting device 1000 shown in Figure 5A.

[0068] The light-emitting device 1000 shown in Figure 5 has a structure that includes a surface light-emitting element 100 that emits light L1 in multiple directions, and multiple light-receiving elements 300 corresponding to each emitted light L1.

[0069] The light-receiving elements 300 are arranged in an array and positioned to correspond to multiple light emission points. This array arrangement makes it possible to individually detect monitor light L2 leaking in at least one direction different from the direction of light emission. In particular, it is preferable that each light-receiving element 300 is arranged to correspond to the direction of leakage of light emitted from the surface light-emitting element 100, and this configuration allows for efficient and highly accurate monitoring of monitor light L2.

[0070] In this embodiment, the surface-emitting element 100 is a Photonic Crystal Surface-Emitting Laser (PCSEL). Unlike VCSELs, PCSELs have the characteristic of emitting multiple laser beams at angles in addition to the vertical direction. By utilizing this characteristic, PCSELs can simultaneously emit lasers at multiple points.

[0071] In this technology, in order to monitor multiple monitor lights leaking from multiple light emission points of the PCSEL in at least one direction different from the direction of light emission, light-receiving elements 300 corresponding to each light emission point are arranged in an array. This array arrangement makes it possible to detect the light intensity and light intensity fluctuations of each emitted light with high precision.

[0072] It is preferable that each light-receiving element 300 is positioned in the opposite direction to the light emitted from the surface-emitting element 100. This arrangement allows for efficient reception of the monitor light L2 leaking from the surface-emitting element 100, thereby reducing the influence of ambient light. Specifically, it is preferable that each light-receiving element 300 is positioned within a range from -15 degrees to +15 degrees, with respect to the opposite direction (180 degrees) from the central axis of the emitted light L1. Furthermore, it is even more preferable that they be positioned within a range with a lower limit of -10 degrees and an upper limit of +10 degrees, and particularly preferable that they be positioned within a range with a lower limit of -5 degrees and an upper limit of +5 degrees.

[0073] The above description of the light-emitting device according to this embodiment can be applied to other embodiments and models of this technology, unless there are any particular technical inconsistencies.

[0074] [(5) Example 4] Another embodiment of the light-emitting device according to the present technology will be described with reference to Figure 6. Figure 6A is a schematic cross-sectional view showing an example of the configuration of a light-emitting device 1000 according to one embodiment of the present technology. Figure 6B is a schematic plan view of the light-emitting device 1000 shown in Figure 6A.

[0075] In the light-emitting device 1000 shown in Figure 6, the surface light-emitting element 100 and the light-receiving element 300 are arranged side by side on the substrate 101, enabling efficient light monitoring and electrode arrangement.

[0076] This light-emitting device 1000 includes, for example, a surface light-emitting element 100 using PCSEL, and has the function of efficiently emitting emitted light L1.

[0077] The light-receiving element 300 is positioned adjacent to the surface-emitting element 100. The light-receiving element 300 is positioned perpendicular to the direction of light emission, and efficiently receives the monitor light L2 leaking in this perpendicular direction. This arrangement of the light-receiving element 300 makes it possible to monitor the light leaking laterally from the surface-emitting element 100, and to accurately control the light power of the emitted light L1 based on this monitor light L2.

[0078] The first cathode electrode 109c connected to the surface light-emitting element 100 has a structure that forms a current-carrying path for current injection.

[0079] The common electrode 109e is an electrode that is connected in common to the surface light-emitting element 100 and the light-receiving element 300.

[0080] The second cathode electrode 109d connected to the photodetector 300 has the role of transmitting the signal detected by the photodetector 300 to an external circuit.

[0081] Furthermore, the light-receiving element 300 and the surface-emitting element 100 are separated by an insulating layer 15. This insulating structure prevents operational interference between the two elements and stabilizes their operation.

[0082] The above description of the light-emitting device according to this embodiment can be applied to other embodiments and models of this technology, unless there are any particular technical inconsistencies.

[0083] [(6) Example 5] Another embodiment of the light-emitting device according to the present technology will be described with reference to Figure 7. Figure 7A is a schematic cross-sectional view showing an example of the configuration of a light-emitting device 1000 according to one embodiment of the present technology. Figure 7B is a schematic plan view of the light-emitting device 1000 shown in Figure 7A.

[0084] In the light-emitting device 1000 shown in Figure 7, the light-receiving elements 300 are simultaneously arranged in the opposite direction and perpendicular to the direction of emission of the emitted light L1. The first light-receiving element 300a is arranged adjacent to the surface light-emitting element 100. The second light-receiving element 300b, the surface light-emitting element 100, and the substrate 101 are stacked in this order. This arrangement allows the light-receiving elements 300 to efficiently receive monitor light L2 leaking in the opposite and perpendicular directions. Such a structure has the effect of significantly improving the stability of light detection by enabling monitoring from multiple directions.

[0085] The above description of the light-emitting device according to this embodiment can be applied to other embodiments and models of this technology, unless there are any particular technical inconsistencies.

[0086] [(7) Example 6] Another embodiment of the light-emitting device according to the present technology will be described with reference to Figure 8. Figure 8A is a schematic cross-sectional view showing an example of the configuration of a light-emitting device 1000 according to one embodiment of the present technology. Figure 8B is a schematic plan view of the light-emitting device 1000 shown in Figure 8A.

[0087] Figure 8B schematically shows the structure as viewed from the side opposite the laser driver 200, with the surface light-emitting element 100 and the substrate 101 visible.

[0088] The light-emitting device 1000 shown in Figure 8 further includes a laser driver 200. This light-emitting device 1000 consists of a substrate 101, a surface light-emitting element 100, a light-receiving element 300, a laser driver 200, a plurality of electrodes 109, 109g, and bumps 109h, etc.

[0089] A surface light-emitting element 100 is positioned on the lower surface of the substrate 101. A laser driver 200 is positioned in the opposite direction to the emission direction of the light L1 emitted from the surface light-emitting element 100 (the direction of the substrate 101). The laser driver 200 supplies current to control the operation of the surface light-emitting element 100 and the light-receiving element 300.

[0090] The laser driver 200 is electrically connected to the surface light-emitting element 100 via a bump 109h. The bump 109h is a conductive member for connecting the surface light-emitting element 100 and the laser driver 200, and is made of a metallic material (e.g., gold or copper), which contributes to efficient current conduction and improved heat distribution.

[0091] The anode electrode 109f is positioned on the side of the surface light-emitting element 100, connected to the surface light-emitting element 100, and supplies a positive current. The cathode electrode 109g is positioned on the surface light-emitting element 100 facing the laser driver 200, connected to the surface light-emitting element 100, and supplies a negative current. The insulating layer 15 provides adequate insulation to prevent short circuits between the electrodes.

[0092] In this embodiment, a light-receiving element 300 is formed on the laser driver 200. This light-receiving element 300 has a structure that receives monitor light L2 leaking through an opening 201 provided at the bottom of the surface light-emitting element 100.

[0093] Specifically, the surface light-emitting element 100 leaks monitor light L2 toward the laser driver 200. This monitor light L2 passes through the aperture 201 and reaches the photodetector 300. The photodetector 300 efficiently receives the monitor light L2 and transmits the signal to the laser driver 200, enabling real-time monitoring and feedback control of the optical output.

[0094] In this configuration, the photodetector 300 is located within the laser driver 200, minimizing the influence of ambient light and efficiently receiving only the monitor light. In particular, a bump 109h is used at the junction of the surface light-emitting element 100 and the laser driver 200. This bump 109h plays a role in reducing the influence of ambient light. By shielding the optical path of ambient light, the bump 109h prevents unwanted light from the external environment from reaching the photodetector 300, thereby improving the signal purity of the monitor light L2.

[0095] Furthermore, by integrally arranging the light-receiving element 300 within the laser driver 200, no additional space is required, and the overall chip size can be reduced.

[0096] Furthermore, integrating the surface light-emitting element 100, the light-receiving element 300, and the laser driver 200 simplifies wiring and electrode arrangement, enabling more efficient manufacturing processes.

[0097] The above description of the light-emitting device according to this embodiment can be applied to other embodiments and models of this technology, unless there are any particular technical inconsistencies.

[0098] [(8) Example 7] Another embodiment of the light-emitting device according to the present technology will be described with reference to Figure 9. Figure 9 is a schematic cross-sectional view showing an example of the configuration of a light-emitting device 1000 according to one embodiment of the present technology.

[0099] As shown in Figure 9, in the light-emitting device 1000 according to this embodiment, a configuration can also be adopted in which a photodetector 300 is provided within the laser driver 200 and a transimpedance amplifier (TIA) circuit 202 is connected to the photodetector 300. With this configuration, the TIA can convert the current signal generated by the photodetector 300 into a voltage signal.

[0100] The minute current signal generated by the photodetector 300 within the laser driver 200 is quickly and efficiently converted into a voltage signal by the TIA circuit 202. This conversion simplifies the input to the subsequent signal processing circuit and improves the efficiency of signal processing.

[0101] Furthermore, by directly forming the TIA circuit 202 within the laser driver 200, external circuits are not required, enabling miniaturization and high-density mounting of the entire device.

[0102] Furthermore, the high-speed operation characteristics of the TIA circuit 202 enable real-time processing of signals from the photodetector 300, allowing for precise monitoring and feedback control of optical signals.

[0103] This configuration is particularly useful in application fields requiring high-precision optical signal processing. Examples include data processing in high-speed optical communications, weak light detection in precision measuring instruments, and improved signal processing efficiency in sensor systems. Furthermore, the integration of the laser driver 200 and the TIA circuit 202 enables lower power consumption and simplification of the overall system.

[0104] The above description of the light-emitting device according to this embodiment can be applied to other embodiments and models of this technology, unless there are any particular technical inconsistencies.

[0105] [2. Second Embodiment of the Technology (Example of Method for Manufacturing a Light-Emitting Device)] The technology provides a method for manufacturing a light-emitting device, which includes forming a surface light-emitting element, configuring the surface light-emitting element to emit light in a predetermined direction, and arranging a light-receiving element that is smaller in size than the surface light-emitting element and receives monitor light leaking in at least one direction different from the direction of light emission.

[0106] The method for manufacturing the light-emitting device of this technology will be described with reference to Figures 10 to 22. Figure 10 is a flowchart showing an example of a method for manufacturing the light-emitting device 1000 according to one embodiment of this technology. Figures 11 to 22 are schematic cross-sectional views showing an example of a method for manufacturing the light-emitting device 1000 according to one embodiment of this technology.

[0107] The overall process involves first simultaneously forming multiple photonic crystal surface-emitting lasers 100 on a substrate 101 (a single wafer, hereinafter referred to as "substrate 101") using semiconductor manufacturing equipment. Subsequently, these are separated by dicing to obtain chip-shaped photonic crystal surface-emitting lasers 100.

[0108] In the first step S101, a first laminate L1 constituting the surface light-emitting element is formed (see Figure 11). Specifically, using an epitaxial growth method such as MOCVD (Metal Organic Chemical Vapor Deposition), the n-type semiconductor layer 102b, p-type semiconductor layer 102a, first cladding layer 103, active layer 104, and base material 105a of the photonic crystal layer 105 are sequentially laminated on a substrate 101 (for example, an n-GaAs substrate) which is the growth substrate. At this time, methyl-based organometallic gases such as trimethylaluminum (TMAl) and trimethylgallium (TMGa) and arsine (AsH) are used as raw materials. ３ ) gas is used. For impurity addition, disilane (Si) is used as a donor. ２ H ６ ), carbon tetrabromide (CBr) as the acceptor ４ Use ).

[0109] In the next step S102, a photonic crystal layer 105 is formed (see Figure 12). Specifically, a resist pattern is formed on the first laminate L1 using photolithography, and this is used as a mask to selectively etch the base material 105a to form regions with different refractive indices 105b (e.g., vacancies). Reactive ion etching (RIE) using a Cl-based gas is suitable for etching. After that, the resist pattern is removed.

[0110] In the next step S103, a second laminate L2 constituting the surface light-emitting element is formed (see Figure 13). By epitaxial growth, a second cladding layer 106, a reflector 107, and a contact layer 108 are sequentially stacked on the first laminate L1 to form the second laminate L2.

[0111] In the next step S104, a mesa is formed (see Figure 14). A resist pattern is formed on the second laminate L2 using photolithography, and this is used as a mask to selectively etch, thereby forming a light-emitting mesa. After that, the resist pattern is removed. The etching is performed to a depth that reaches, for example, the substrate 101. This makes it possible to configure the surface light-emitting element to emit light in a predetermined direction.

[0112] In the next step S105, a photodetector 300 is formed that is smaller than the surface-emitting element and receives monitor light leaking in at least one direction different from the direction of light emission (see Figure 15). Specifically, after forming the pattern of the photodetector using photolithography technology, the n layer 304, p layer 301, i layer 302, and n layer 303 are sequentially stacked by epitaxial growth. Next, the photodetector 300 is made smaller than the surface-emitting element by selective etching.

[0113] In the next step S106, the first insulating film 151 is formed (see Figure 16). The first insulating film 151 is formed over the entire surface so as to cover the photodetector 300. Chemical vapor deposition (CVD), sputtering, or vapor deposition methods are used to form the insulating film. SiO is used as the material for the insulating film. ２ Ya Si ３ N ４ Materials with excellent insulating properties, such as those mentioned above, are used.

[0114] In the next step, S107, contact holes CH1 are formed (see Figure 17). First, a resist pattern is formed using photolithography. Using this pattern as a mask, the first insulating film 151 is selectively processed using a dry etching method to form contact holes CH1. After etching is complete, the resist pattern is removed.

[0115] In the next step S108, the contact electrode 109a is formed (see Figure 18). This step uses the lift-off method. Specifically, first, a resist layer for forming the electrode pattern is formed using photolithography technology. Then, conductive materials such as Au (gold), Al (aluminum), and Ti (titanium) are deposited by vapor deposition or sputtering. Unwanted material is removed by the lift-off process to form the contact electrode 109a. The contact electrode 109a ensures electrical connection between the photodetector 300 and the external circuit.

[0116] In the next step S109, the second cathode electrode 109d is formed (see FIG. 19). This electrode plays a role in equalizing the current density and suppressing the voltage drop. For the formation of the second cathode electrode 109d, the lift-off method is used, and Au or Al is deposited as a thick film (for example, 2 μm). As a result, the operating efficiency of the light-emitting element and the light-receiving element is improved.

[0117] In the next step S110, the common electrode 109e is formed (see FIG. 20). For the formation of the common electrode 109e, a vapor deposition method or a sputtering method is used, and a highly conductive material such as Au or Cu (copper) is deposited.

[0118] In the next step S111, the second insulating film 152 is formed (see FIG. 21). In this process, a vapor deposition method or a sputtering method is used. As the material of the insulating film, SiO ２ or Si ３ N ４ is suitable and provides electrical insulation of the device and protection from the external environment.

[0119] In the last step S112, the first cathode electrode 109c is formed (see FIG. 22). For electrode formation, the lift-off method is used, and high conductivity is achieved by depositing Au, Al, or Cu.

[0120] The above description of the manufacturing method of the light-emitting device according to this embodiment can be applied to other examples and embodiments of the present technology as long as there is no particular technical contradiction.

[0121] [3. Third Embodiment of the Present Technology (Example 2 of Light-Emitting Device)] [(1) Monitoring of Light-Emitting Element] The light-emitting element array has a structure in which a plurality of light-emitting elements are regularly arranged, and is used in a wide variety of applications such as high-output light sources, high-resolution displays, and sensor technologies.

[0122] Conventionally, the output monitoring method for light-emitting element arrays generally involved continuously measuring the output of each element and controlling the system based on the measurement results. However, with this method, as the number of elements increases, the amount of data becomes enormous, leading to increased data processing time and processing delays. Furthermore, it was difficult to efficiently monitor the output of each element at high speed and with low power consumption. Moreover, such conventional methods required circuit configurations with high data processing capabilities, which inevitably led to increased power consumption and higher costs.

[0123] Therefore, the primary objective of this technology is to provide a method for efficiently and quickly monitoring the output of each element in a light-emitting element array, thereby reducing power consumption and suppressing the overall system cost, in order to solve these problems.

[0124] [(2) Overview of this embodiment] An embodiment of the light-emitting device according to this technology will be described in detail below. This technology provides a light-emitting device that efficiently monitors the output of multiple light-emitting elements and processes information on an event basis.

[0125] This technology provides a light-emitting device comprising: a difference detection unit that detects the difference between the input / output signals corresponding to each of a plurality of light-emitting elements and a reference value; an event generation unit that generates an event based on the comparison result of the difference with a predetermined threshold; and an output unit that outputs event information including identification information that identifies the light-emitting element that generated the event.

[0126] An example of the configuration of the light-emitting device of this technology will be described with reference to Figure 23. Figure 23 is a block diagram showing an example of the configuration of a light-emitting device 1000 according to one embodiment of this technology.

[0127] As shown in Figure 23, the light-emitting device 1000 of this technology includes a plurality of light-emitting elements 100, a signal processing unit 10, and an arbitration circuit 14, etc. The signal processing unit 10 includes a difference detection unit 11, an event generation unit 12, and an output unit 13, etc.

[0128] The light-emitting device 1000 has a configuration in which multiple light-emitting elements 100 are arranged in an array. This array arrangement ensures that the light-emitting elements 100 are regularly aligned, enabling high-density and efficient light output.

[0129] Each light-emitting element 100 may have a configuration that emits laser light. This makes it possible to operate as a high-power and high-precision light source. Furthermore, the light-emitting element 100 may have a configuration that operates in single mode in transverse mode. Single-mode operation improves the output beam quality of the light and maintains high spatial coherence.

[0130] Furthermore, the light-emitting element 100 may be composed of a surface light-emitting element. By employing a surface light-emitting element, it is possible to miniaturize the entire light-emitting device and form an efficient array structure. An example of a surface light-emitting element may include a photonic crystal surface-emitting laser (PCSEL). By using a PCSEL, a light source with high directivity and broad wavelength selectivity can be realized.

[0131] The difference detection unit 11 detects the difference between the input / output signal corresponding to each of the multiple light-emitting elements 100 and a reference value. The difference detection unit 11 has a configuration that detects the difference between the input / output signal and the reference value asynchronously. This asynchronous operation achieves high responsiveness.

[0132] The event generation unit 12 generates event information based on the comparison result between the difference detected by the difference detection unit 11 and a predetermined threshold. For example, when the event generation unit 12 detects an output change that exceeds the threshold, it generates an event based on the output voltage change from the light-emitting element. When an event occurs, the voltage at that time is reset as the reference voltage, and a new threshold is set for the detection of the next event.

[0133] The light-emitting device 1000 includes an arbitration circuit 14 for arbitrating events associated with each of the multiple light-emitting elements 100 in the order in which they occur and outputting them sequentially. When events occur simultaneously in multiple light-emitting elements, the arbitration circuit organizes these events in the order in which they occur and transmits them sequentially to the output unit 13. This configuration guarantees the order of the data and facilitates processing by external systems.

[0134] The output unit 13 outputs event information that includes identification information to identify the light-emitting element that generated the event. This identification information includes at least one of the following: coordinates to identify the light-emitting element that generated the event, the time the event occurred, and the polarity of the event.

[0135] The coordinates are information that identifies the physical position of the light-emitting element 100, which is the source of the event. These coordinates are defined as numerical values ​​indicating the positions on the X and Y axes, for example, based on the array structure of the light-emitting element array. If the array has a three-dimensional structure, it is also possible to include information on the Z axis. This coordinate information uniquely identifies the physical position of the light-emitting element 100.

[0136] The event occurrence time is information indicating when an event occurred, and is based on, for example, the point in time when the output fluctuation of the light-emitting element 100 exceeds a predetermined threshold. This occurrence time is recorded with high precision based on a reference clock shared within the system. This establishes the temporal order of events occurring in multiple light-emitting elements 100.

[0137] The polarity of an event is information that identifies a "positive polarity" when the output fluctuation of the light-emitting element 100 exceeds a positive threshold, and a "negative polarity" when it exceeds a negative threshold. This polarity information indicates the direction of the output fluctuation of the light-emitting element 100 and is an important indicator for anomaly detection and determination of the operating state.

[0138] [(3) Operation and Threshold Setting] The operation of the light-emitting device 1000 of this technology will now be described. The difference detection unit 11 continuously monitors the difference between the input / output signal and a reference value. This input / output signal may be, for example, the drive current or the voltage across the light-emitting element 100. When the difference between this input / output signal and the reference value (reference current or reference voltage) exceeds a threshold, the event generation unit 12 identifies the light-emitting element that was the source of the event and generates its coordinates, the time of the event, and the polarity of the event (positive or negative) as identification information. For example, if the output power of the light-emitting element changes by a certain ratio or more, a positive polarity event is output if the change exceeds the positive threshold, and a negative polarity event is output if the change exceeds the negative threshold. In addition, in order to prevent the detection of unintended power fluctuations, a time-varying threshold is applied when operation involves current modulation.

[0139] Furthermore, if an event occurs in multiple light-emitting elements 100, the arbitration circuit 14 organizes the events in the order they occurred, and the output unit transmits the event information to an external system.

[0140] The operation and thresholds of the light-emitting device 1000 will be explained with reference to Figures 24 and 25. Figures 24 and 25 are graphs showing an example of the operation and thresholds of the light-emitting device 1000 according to one embodiment of this technology.

[0141] Figure 24A is a graph showing the relationship between the drive current I of the light-emitting element 100 and time t when normal voltage fluctuations occur during startup. Specifically, it shows that the drive current increases with time, and then stabilizes after reaching a constant value.

[0142] The drive current I increases linearly from the initial state until it reaches the threshold current required to start the operation of the light-emitting element 100. During this process, the semiconductor laser transitions to the normal light-emitting state. After the current reaches a predetermined value, it maintains that value, and the operation of the light-emitting element 100 stabilizes. As a result, the optical output remains constant, and continuous wave (CW) operation is established.

[0143] Figure 24B is a graph showing the relationship between the voltage V at the light-emitting element 100 and time t when normal voltage fluctuations occur during startup. The voltage increases with time, and then stabilizes after reaching a constant value.

[0144] When the drive current begins to flow, the terminal voltage V of the light-emitting element 100 increases over time. At this time, the rate of change (rate of change k) of the voltage is calculated as ΔV / Δt. When the voltage reaches a predetermined value, it maintains that value and transitions to stable operation. This corresponds to the state in which the light-emitting element 100 is emitting light normally.

[0145] Figure 24C is a graph showing the time evolution of the positive threshold value to be set. The threshold value changes dynamically according to time t and stabilizes after a certain period of time has elapsed.

[0146] In the initial stage, the threshold is set to increase proportionally to time t, based on the rate of change k of the current or voltage. By setting the threshold according to time changes, it is possible to appropriately distinguish between normal and abnormal fluctuations during the rise phase of the current or voltage. The threshold is set to reach a constant value after a predetermined time has elapsed.

[0147] Figure 24D is a graph showing the time change of the negative threshold value to be set. The threshold value is set to a constant value.

[0148] Regarding voltage fluctuations that occur during startup, the event generation unit 12 recognizes this as a normal startup operation if the voltage does not reach a threshold on the positive or negative side from the reference value, and therefore no event is generated.

[0149] On the other hand, Figures 25A to 25D are graphs showing an example of the operation and threshold of the light-emitting element 100 when an abnormal voltage fluctuation occurs during startup. Note that Figures 25A, 25C, and 25D are the same as those in Figure 24.

[0150] Figure 25B is a graph showing the relationship between the voltage V and time t in the light-emitting element 100 when an abnormal voltage fluctuation occurs during startup.

[0151] During the startup process, if an unexpected abnormal voltage occurs, a temporary fluctuation will occur in the voltage signal. This fluctuation may exceed the positive and negative thresholds set as reference values.

[0152] As shown in Figure 25E, the event generation unit 12 detects an anomaly only when the voltage exceeds a threshold and generates an event. In the graph, the vertical axis represents output O and the horizontal axis represents time t, and it can be seen that the output O changes and an event occurs when an abnormal voltage fluctuation is detected. As a result, event information including the time when the abnormal voltage fluctuation occurred, the light-emitting element that is the source, and the polarity (positive or negative) is output.

[0153] Next, the operation and thresholds of the light-emitting element 100 during continuous wave (CW) operation will be explained with reference to Figures 26 and 27. Figures 26 and 27 are graphs showing an example of the operation and thresholds of a light-emitting device 1000 according to one embodiment of this technology.

[0154] Figure 26A is a graph showing the relationship between the drive current I of the light-emitting element 100 and time t when normal CW operation is being performed. The current value remains stable at a constant value.

[0155] Figure 26B is a graph showing the relationship between voltage V and time t in the light-emitting element 100 when normal CW operation is being performed. The current value is also stable at a constant value.

[0156] Figure 26C is a graph showing the time change of the positive threshold value to be set. The threshold value is set to a constant value.

[0157] Figure 26D is a graph showing the time change of the negative threshold value to be set. The threshold value is set to a constant value.

[0158] In CW operation, the event generation unit 12 recognizes that the value does not reach a threshold on the positive or negative side from the reference value as normal CW operation, and therefore no event is generated.

[0159] On the other hand, Figures 27A to 27D are graphs showing an example of the operation and threshold of the light-emitting element 100 when an abnormal voltage fluctuation occurs during CW operation. Note that Figures 27A, 27C, and 27D are the same as those in Figure 26.

[0160] Figure 27B is a graph showing the relationship between the voltage V at the light-emitting element 100 and time t when an abnormal voltage fluctuation occurs during CW operation.

[0161] In CW operation, if an unexpected abnormal voltage occurs, a temporary fluctuation will occur in the voltage signal. This fluctuation may exceed the positive and negative threshold values ​​set as the reference value.

[0162] As shown in Figure 27E, the event generation unit 12 detects an abnormality only when the voltage exceeds a threshold and generates an event. This outputs event information including the time the abnormal voltage fluctuation occurred, the light-emitting element that is the source, and the polarity (positive or negative).

[0163] To accommodate current modulation, the positive and negative thresholds can be varied over time. Specifically, the thresholds have a programmable configuration based on the time variation of the current, and can be flexibly set according to dynamically changing current modulation conditions.

[0164] When current modulation is performed, the current flowing through the light-emitting element 100 fluctuates over time, and the voltage changes accordingly. In such situations, conventional static threshold settings may misdetect fluctuations caused by normal current modulation as abnormalities. This technology makes it possible to change the positive and negative thresholds over time according to the temporal rate of change and pattern of the current modulation, thereby preventing false detections during current modulation.

[0165] The temporal change in the threshold is programmable and can be modified according to a predetermined control signal or setting condition. This allows for flexible adaptation to different operating modes and environments.

[0166] [(4) Circuit] Figure 28 is a circuit diagram showing a partial configuration of a light-emitting device 1000 according to one embodiment of the present technology. This configuration includes basic components for monitoring the operation of the light-emitting element 100 and shows a mechanism for detecting output fluctuations of the light-emitting element 100 using a difference detection unit 11.

[0167] The current source 15 is for supplying drive current to the light-emitting element 100 and is responsible for current control to ensure that the light-emitting element 100 operates stably.

[0168] The light-emitting element 100 connected to the current source 15 outputs light in accordance with the supplied current.

[0169] The output voltage of the light-emitting element 100 is input to the difference detection unit 11 via a capacitor. The difference detection unit 11 has the function of detecting the difference between the voltage across the light-emitting element 100 and a reference value.

[0170] The output of the difference detection unit 11 is sent to the comparator 121. This comparator 121 constitutes the event generation unit 12 described above, and compares the detected difference signal with a predetermined positive or negative threshold, and generates an event if, for example, the difference exceeds the threshold. The generated event is output as a positive event or a negative event.

[0171] [(5) Effects] This technology provides a method for efficiently monitoring the voltage fluctuations, i.e., power fluctuations, of a light-emitting element without requiring a complex fast Fourier transform (FFT). In the configuration of this technology, an event is output only when the difference between the input / output signal and a reference value exceeds a predetermined threshold. Therefore, it is possible to ignore noise fluctuations of interest and power fluctuations caused by intentional modulation.

[0172] Furthermore, since data is output only when a threshold is exceeded, the amount of data can be significantly reduced even in structures where multiple light-emitting elements are arranged in an array. As a result, low-latency data processing is achieved, and high-speed response is improved. In addition, by using an arbitration circuit to output events in the order they occur, complex circuit design is not required, and high-speed data processing with low power consumption is possible.

[0173] The effects described herein are not necessarily limited and may be any of the effects described in this disclosure. Furthermore, the effects described herein will also occur in other embodiments and examples described later.

[0174] The above description of the light-emitting device according to this embodiment can be applied to other embodiments and models of this technology, unless there are any particular technical inconsistencies.

[0175] [(6) Example 1] In this embodiment, the difference detection unit 11 may be equipped with an amplifier. This will be explained with reference to Figure 29. Figure 29 is a block diagram showing an example configuration of a light-emitting device 1000 according to one embodiment of the present technology.

[0176] As shown in Figure 29, the light-emitting device 1000 is equipped with an amplifier 111. The amplifier 111 detects the difference between the input / output signal (for example, the voltage across the light-emitting element) and a reference value, and dynamically adjusts the gain according to that difference.

[0177] The operation of this amplifier will be explained with reference to Figure 30. Figure 29 is a graph showing the operation of amplifier 111 according to one embodiment of this technology. The horizontal axis shows the difference D between the input / output signal and the reference value, and the vertical axis shows the output voltage of the difference detection unit 11. A threshold value T is also shown.

[0178] As shown in Figure 30, when the difference D between the input / output signal and the reference value is small, increasing the gain of the amplifier makes it possible to detect minute voltage differences with high accuracy. On the other hand, when the difference D between the input / output signal and the reference value is large, decreasing the gain prevents the amplifier output from saturating, thereby achieving a wide dynamic range.

[0179] When a light-emitting element starts operating or when minute output fluctuations occur, the difference between the input / output signal and the reference value is small. In this case, the amplifier operates in high-gain mode, amplifying and detecting even small voltage differences.

[0180] When a light-emitting element exhibits rapid output fluctuations or is in an abnormal state, the difference between the input / output signal and the reference value becomes large. In this case, the amplifier reduces its gain to prevent the output signal from saturating and maintain the linearity of the signal.

[0181] By switching between high-gain and low-gain modes, the differential detection unit can handle a wide range of voltage differences. This allows for high-precision detection of both minute and large signal changes.

[0182] The above description of the light-emitting device according to this embodiment can be applied to other embodiments and models of this technology, unless there are any particular technical inconsistencies.

[0183] [(7) Example 2] This embodiment is characterized by further comprising a light-receiving element (e.g., a photodetector) for receiving light emitted from the light-emitting element, thereby enhancing output monitoring and control of the light-emitting element.

[0184] An example of the configuration of the light-emitting device 1000 according to this embodiment will be described with reference to Figure 31. Figure 31 is a circuit diagram showing an example of the configuration of the light-emitting device 1000 according to one embodiment of this technology. The differences from Figure 28 will be described below.

[0185] As shown in Figure 31, the light-emitting device 1000 further includes a light-receiving element 300 that receives the light emitted from the light-emitting element 100. The light-receiving element 300 converts the optical signal from the light emitted from the light-emitting element 100 into an electrical signal for subsequent processing.

[0186] Light incident on the photodetector 300 is output as a current signal. This current signal is converted into a voltage signal by the transimpedance amplifier (TIA) 16. By converting the current signal into a voltage signal, the TIA 16 effectively amplifies the output signal of the photodetector 300, making it possible to process weak light signals with high precision.

[0187] Furthermore, the TIA16's configuration, which directly converts current signals, improves signal processing speed, enabling real-time monitoring and feedback control.

[0188] The output signal of TIA16 is input to bandpass filter 17. This bandpass filter 17 allows only signals within a specific frequency band to pass through, removing noise components.

[0189] Finally, the filtered signal is sent to the signal processing unit 10, where it is used for detailed analysis and generation of control information. The output unit of the signal processing unit 10 outputs event information based on the signal from the photodetector 300 and the events generated by the event generation unit 12.

[0190] Next, the operation of this circuit will be explained. The light-emitting element 100 operates using a drive current supplied from the current source 15 and generates emitted light. This emitted light is received by the light-receiving element 300 and converted into an electrical signal.

[0191] Simultaneously, the voltage across the light-emitting element 100 is compared with a reference voltage by the difference detection unit 11, and the difference is evaluated by the comparator 121. If the difference exceeds a set threshold, a positive or negative event is generated, and abnormal operation or a change in the operating state of the light-emitting element is detected.

[0192] The signal obtained from the photodetector 300 is converted into a voltage signal by the transimpedance amplifier 16, and then only specific frequency components are extracted by the bandpass filter 17. Finally, it is sent to the output unit of the signal processing unit 10 and used for outputting information to an external system or generating control signals.

[0193] This technology enables highly precise control of the operating state of the light-emitting element 100 by directly monitoring the light output using the light-receiving element 300.

[0194] The above description of the light-emitting device according to this embodiment can be applied to other embodiments and models of this technology, unless there are any particular technical inconsistencies.

[0195] [(8) Example 3] The light-emitting device of this technology may further include a control unit that controls the drive current or temperature of the light-emitting element based on event information. This will be explained with reference to Figure 32. Figure 32 is a circuit diagram showing a part of the configuration of a light-emitting device 1000 according to one embodiment of this technology, and shows a configuration for monitoring the output of the light-emitting element 100 and realizing dynamic feedback control. The differences from Figure 28 will be explained below.

[0196] As shown in Figure 32, the light-emitting device 1000 includes a control unit 18 that controls the drive current or temperature of the light-emitting element 100 based on event information. Event information generated by the comparator 121 is sent to the control unit 18, and the drive current or temperature of the light-emitting element 100 is dynamically adjusted. The control unit 18 performs feedback control in response to the event to improve the output stability of the light-emitting element 100. Through feedback control, the output of the light-emitting element 100 is maintained within the set value, and abnormal operation or output fluctuations are immediately corrected.

[0197] This technology allows the control unit 18 to control the drive current or temperature, thereby stabilizing the operation of the light-emitting element 100 over the long term and improving its resistance to disturbances and environmental fluctuations.

[0198] The above description of the light-emitting device according to this embodiment can be applied to other embodiments and models of this technology, unless there are any particular technical inconsistencies.

[0199] [(9) Example 4] Another example of the configuration of the light-emitting device 1000 will be described with reference to Figure 33. Figure 33 is a schematic cross-sectional view showing an example of the configuration of the light-emitting device 1000 according to one embodiment of the present technology.

[0200] As shown in Figure 33, the light-emitting device 1000 further includes a laser driver 200, and the light-emitting element 100, the laser driver 200, and the signal processing unit 10 are stacked in this order and electrically connected to each other.

[0201] An AR film (anti-reflective film) 110 that reduces light reflection loss is formed on one side of the substrate 101, and a light-emitting element 100 is arranged on the other side.

[0202] The light-emitting element 100 has a back-side emission type structure that emits the emitted light L1 in the direction of the substrate 101. The light-emitting element 100 may be, for example, a surface-emitting element, and is composed of, for example, a VCSEL (Vertical-Cavity Surface-Emitting Laser), a PCSEL (Photonic Crystal Surface-Emitting Laser), or a VeCSEL (Vertical-Extended Cavity Surface-Emitting Laser).

[0203] The laser driver 200 is responsible for controlling the drive current supplied to the light-emitting element 100. The laser driver 200 is an important component for ensuring the stability of the optical output.

[0204] At the bottom layer is a signal processing unit 10, which includes a difference detection unit 11 and a comparator 121. The signal processing unit 10 has functions to monitor the output of the light-emitting element 100 and control its operation on an event basis.

[0205] The light-emitting element 100 and the laser driver 200 are electrically connected by a bump 109h made of Au or Cu. The laser driver 200 and the signal processing unit 10 are electrically connected by a Cu-Cu connection.

[0206] According to this technology, by connecting a chip having a light-emitting element 100, a chip having a laser driver 200, and a chip having a signal processing unit 10 with Au or Cu to form a stacked structure, miniaturization becomes possible, and a compact light-emitting device can be provided.

[0207] This technology employs a back-side emission structure, which uniformizes current and heat distribution, improving the quality and stability of the output beam. This characteristic is particularly useful in high-precision sensing and communication applications.

[0208] This technology reduces inductance due to the back-side emission structure, enabling high-speed monitoring of the light-emitting element's voltage signal. This improves the overall system response speed and enables real-time control.

[0209] The above description of the light-emitting device according to this embodiment can be applied to other embodiments and models of this technology, unless there are any particular technical inconsistencies.

[0210] [(10) Example 5] Another example of the configuration of the light-emitting device 1000 will be described with reference to Figure 34. Figure 34 is a schematic cross-sectional view showing an example of the configuration of the light-emitting device 1000 according to one embodiment of this technology. The differences from Figure 33 will be described below.

[0211] As shown in Figure 34, the light-emitting device 1000 further includes a light-receiving element 300 that receives the light emitted from the light-emitting element 100. This light-emitting element 100 is, for example, a photodetector, and is responsible for converting the optical signal into an electrical signal and monitoring the output of the light-emitting element.

[0212] A laser driver 200 that supplies drive current to the light-emitting element 100 and a bias circuit (not shown) for driving the photodetector 300 are located at the bottom of the substrate 101. This allows for integrated control of the operation of the light-emitting element 100 and the photodetector 300.

[0213] At the lowest level, a signal processing unit 10 is arranged, which includes a difference detection unit 11, a comparator 121, and an output unit 13. The output unit 13 outputs event information based on the signal from the photodetector 300 and the events generated by the event generation unit (not shown).

[0214] According to this technology, by using an event monitor and a light-receiving element 300 in combination, it is possible to precisely monitor the operation of the light-emitting element 100 and perform anomaly detection and output control with high accuracy.

[0215] The above description of the light-emitting device according to this embodiment can be applied to other embodiments and models of this technology, unless there are any particular technical inconsistencies.

[0216] [(11) Example 6] An example of the configuration of another light-emitting device 1000 will be described with reference to Figure 35. Figure 35 is a circuit diagram showing a part of the configuration of a light-emitting device 1000 according to one embodiment of the present technology, and shows that it can be realized not only on a voltage basis but also on a current basis.

[0217] The current source 15 is directly connected to the light-emitting element 100 and supplies a drive current. This current causes the light-emitting element 100 to operate and emit light. This current is also input to the difference detection unit 11. The output signal of the difference detection unit 11 is sent to the comparator 121 and compared with positive and negative thresholds. The output of the comparator 121 is connected to a circuit that generates a positive or negative event. This allows, for example, a corresponding event to be generated immediately when the difference exceeds a set threshold.

[0218] This technology allows for flexible design tailored to specific applications by monitoring either voltage or current as the reference. Alternatively, monitoring may be performed using both voltage and current as the reference.

[0219] The above description of the light-emitting device according to this embodiment can be applied to other embodiments and models of this technology, unless there are any particular technical inconsistencies.

[0220] [4. Fourth Embodiment of the Technology (Example of Sensing Method for Light-Emitting Device)] The technology provides a sensing method for light-emitting devices, which includes detecting the difference between the input / output signals corresponding to each of a plurality of light-emitting devices and a reference value, generating an event based on the comparison result of the difference with a predetermined threshold, and outputting event information including identification information that identifies the light-emitting device that generated the generated event.

[0221] The sensing method of this technology will be explained with reference to Figure 36. Figure 36 is a flowchart showing an example of a sensing method for a light-emitting element according to one embodiment of this technology.

[0222] As shown in Figure 36, first, in step S1, the difference between the input / output signal corresponding to each of the multiple light-emitting elements and a reference value is detected. By performing the difference detection asynchronously, high-speed and high-precision monitoring becomes possible.

[0223] Next, in step S2, the detected difference is compared with a predetermined threshold, and an event is generated based on the result. The event reflects either a positive or negative change.

[0224] Finally, in step S3, event information is output that includes identification information to identify the light-emitting element that is the source of the generated event. This identification information includes at least one of the coordinates of the light-emitting element that is the source of the event, the time the event occurred, and the polarity of the event.

[0225] This method can be used in various application fields, such as FMCW (Frequency Modulated Continuous Wave) LiDAR and SMI (Self-Mixing Interferometry).

[0226] FMCW LiDAR precisely measures the distance and speed to an object by modulating a continuous wave with a specific frequency modulation pattern and detecting the reflected light from the target. This technology plays a crucial role in spatial recognition and object tracking systems in autonomous vehicles and robotics.

[0227] By applying this sensing method, it becomes possible to automatically generate an event when the modulation signal of a light-emitting element deviates from a reference value, enabling real-time monitoring of the operating state of the light-emitting element. This event generation function allows for efficient collection and analysis of the signal characteristics of reflected light, enabling rapid identification of operational abnormalities in individual light-emitting elements.

[0228] Furthermore, in LiDAR systems using multiple light-emitting elements, it is possible to improve the overall analysis efficiency of the system by integrating data from each element using an arbitration circuit based on event information. This increases measurement accuracy and improves the processing speed of reflected data, enabling real-time response in dynamic environments.

[0229] In contrast, in SMI (Surface Mixing Ion), light emitted from a light-emitting element is reflected off the target surface, and some of it returns to the light-emitting element, generating an interference signal due to the self-mixing of light. This interference signal is used to measure minute positional and velocity changes of an object with high precision. SMI is expected to have applications in a wide range of fields, including precision measurement, biosensing, industrial vibration analysis, and micromachine operation monitoring.

[0230] By introducing this technology, abnormal operation and environmental changes can be immediately detected by comparing the output fluctuations and interference signal characteristics of the light-emitting elements with reference values ​​and generating an event when a threshold is exceeded. This allows for more accurate collection of target location information and movement data, as well as improved measurement reliability.

[0231] Furthermore, by using event-based monitoring technology, it is possible to perform signal processing at high speed and with low power consumption while minimizing the amount of data required. In these application fields, this technology not only enables high-precision measurement and real-time response in dynamic environments, but also contributes to reducing overall system power consumption and improving data processing efficiency. Moreover, since it operates without compromising efficiency even in large array structures containing multiple light-emitting elements, it is extremely useful as a next-generation sensing technology.

[0232] The above description of the sensing method of the light-emitting device according to this embodiment can be applied to other embodiments and models of this technology, unless there are any particular technical inconsistencies.

[0233] [5. Fifth Embodiment of the Technology (Example of a Distancing Device)] The Technology provides a distance measuring device equipped with a light-emitting device according to the first and third embodiments.

[0234] An example of the configuration of the distance measuring device according to this embodiment will be described with reference to Figure 37. Figure 37 is a block diagram showing an example of the configuration of a distance measuring device 5000 according to one embodiment of this technology.

[0235] As shown in Figure 37, the distance measuring device 5000 includes a light-emitting device 1000, an imaging device 2000, and a control device 3000.

[0236] The light-emitting device 1000 functions as a light source for the imaging device 2000 to image the subject 4000. The distance measuring device 5000 illuminates the subject 4000 with light emitted from the light-emitting device 1000, and the imaging device 2000 receives the light reflected from the subject 4000 to image the subject 4000. The control device 3000 measures (calculates) the distance to the subject 4000 using the image signal output from the imaging device 2000.

[0237] The light-emitting device 1000 includes a light-emitting unit 1001, a drive circuit 1002, a power supply circuit 1003, and a light-emitting optical system 1004. The imaging device 2000 includes an image sensor 2001, an image processing unit 2002, and an imaging optical system 2003, and the control device 3000 includes a distance measuring unit 3001.

[0238] The light-emitting unit 1001 emits laser light for irradiating the subject 4000. The light-emitting unit 1001 in this embodiment comprises, for example, a plurality of light-emitting elements arranged in a two-dimensional array, and each light-emitting element has, for example, a VCSEL structure. These light-emitting elements are provided within an LD (Laser Diode) chip 1005, and the emitted light is irradiated onto the subject 4000.

[0239] The drive circuit 1002 is an electrical circuit that drives the light-emitting unit 1001. The power supply circuit 1003 is an electrical circuit that generates the power supply voltage supplied to the drive circuit 1002. For example, the power supply circuit 1003 converts the input voltage supplied from the battery in the distance measuring device 5000, and the drive circuit 1002 uses that voltage to drive the light-emitting unit 1001. In this embodiment, the drive circuit 1002 is located within the LDD (Laser Diode Driver) substrate 1006.

[0240] The light-emitting optical system 1004 is equipped with various optical elements to accurately illuminate the subject 4000 with light from the light-emitting unit 1001. Similarly, the imaging optical system 2003 is equipped with optical elements to accurately receive reflected light from the subject 4000.

[0241] The image sensor 2001 receives light from the subject 4000 via the imaging optical system 2003, converts it into an electrical signal through photoelectric conversion. In this embodiment, a CCD (Charge Coupled Device) sensor or a CMOS (Complementary Metal Oxide Semiconductor) sensor is used. The image sensor 2001 converts the optical signal from an analog signal to a digital signal through A / D (Analog to Digital) conversion and outputs it to the image processing unit 2002.

[0242] Furthermore, the image sensor 2001 outputs a frame synchronization signal to the drive circuit 1002, and the drive circuit 1002 accurately drives the light-emitting unit 1001 in accordance with the frame period based on this synchronization signal. This adjusts the timing of light emission and improves the accuracy of distance measurement.

[0243] The image processing unit 2002 has the function of performing various image processing on the image signal output from the image sensor 2001, and is equipped with an image processing processor such as a DSP (Digital Signal Processor).

[0244] The control device 3000 controls the overall operation of the distance measuring device 5000, and controls the illumination of the light-emitting device 1000 and the imaging of the imaging device 2000. The control device 3000 includes a CPU (Central Processing Unit), ROM (Read-Only Memory), RAM (Random Access Memory), etc.

[0245] The distance measuring unit 3001 measures the distance to the subject 4000 based on the signal output from the image sensor 2001 and the results processed by the image processing unit 2002. The distance measuring unit 3001 can employ, for example, the STL (Structured Light) method or the ToF (Time of Flight) method as the distance measuring method. This makes it possible to measure the distance between the distance measuring device 5000 and the subject 4000 in sections based on the image signal, and also makes it possible to identify the three-dimensional shape of the subject 4000.

[0246] The above description of the rangefinder according to the fifth embodiment of this technology can be applied to other embodiments of this technology, unless there are any particular technical inconsistencies.

[0247] [6. Sixth Embodiment of the Technology (Example of Electronic Device)] The technology can be applied to various products (electronic devices). The technology provides an electronic device comprising any of the light-emitting element, driving element, light-emitting device, and distance measuring device according to the first to eleventh embodiments.

[0248] The light-emitting device according to this technology can be applied, for example, to optical communication technology. This device can be used as a light source for high-speed transmission of optical signals in optical fiber communications and high-speed interconnects in data centers. In particular, it can be applied as a light source in the signal transmission section of optical communication systems using VCSELs and PCSELs.

[0249] The light-emitting device according to this technology can be applied, for example, to sensor technology. This device can be applied to facial recognition systems in smartphones and tablet devices, and to distance measurement systems utilizing LiDAR technology. As a result, it functions as a light source in sensor systems that detect the distance and shape of objects with high precision.

[0250] The light-emitting device according to this technology can be applied, for example, to display technology. This light-emitting device can be applied to micro-LED displays and other next-generation display technologies. By using high-density light-emitting elements, high-resolution and low-power displays can be realized.

[0251] The light-emitting device related to this technology can be applied to medical devices. It can be used in medical devices that utilize optical signals, such as pulse oximeters and bio-optical monitoring devices. By achieving high-precision optical output, it contributes to improving diagnostic accuracy.

[0252] The light-emitting device related to this technology will be incorporated into augmented reality (AR) and virtual reality (VR) devices and used as a light source for spatial recognition and interface operation. This will enable high-speed and precise data acquisition, contributing to an improved user experience.

[0253] This technology may be implemented as a device mounted on any type of mobile vehicle, such as an automobile, electric vehicle, hybrid electric vehicle, motorcycle, bicycle, personal mobility device, airplane, drone, ship, or robot.

[0254] Figure 38 is a block diagram showing a schematic configuration example of a vehicle control system, which is an example of a mobile control system to which the technology described herein may be applied.

[0255] The vehicle control system 12000 comprises a plurality of electronic control units connected via a communication network 12001. In the example shown in Figure 38, the vehicle control system 12000 includes a drive system control unit 12010, a body system control unit 12020, an external information detection unit 12030, an internal information detection unit 12040, and an integrated control unit 12050. The functional configuration of the integrated control unit 12050 is shown in the figure, which includes a microcomputer 12051, an audio / image output unit 12052, and an in-vehicle network interface 12053.

[0256] The drivetrain control unit 12010 controls the operation of devices related to the vehicle's drivetrain according to various programs. For example, the drivetrain control unit 12010 functions as a control device for a drivetrain generating device that generates driving force for the vehicle, such as an internal combustion engine or a drive motor; a drivetrain transmission mechanism that transmits driving force to the wheels; a steering mechanism that adjusts the steering angle of the vehicle; and a braking device that generates braking force for the vehicle.

[0257] The body system control unit 12020 controls the operation of various devices mounted on the vehicle body according to various programs. For example, the body system control unit 12020 functions as a control device for a keyless entry system, a smart key system, a power window system, or various lamps such as headlights, reverse lights, brake lights, turn signals, or fog lights. In this case, the body system control unit 12020 may receive radio waves transmitted from a portable device that replaces a key or signals from various switches. The body system control unit 12020 receives these radio waves or signals and controls the vehicle's door lock system, power window system, lamps, etc.

[0258] The external information detection unit 12030 detects information from outside the vehicle equipped with the vehicle control system 12000. For example, an imaging unit 12031 is connected to the external information detection unit 12030. The external information detection unit 12030 causes the imaging unit 12031 to capture images of the outside of the vehicle and receives the captured images. Based on the received images, the external information detection unit 12030 may perform object detection processing such as detecting people, cars, obstacles, signs, or characters on the road surface, or distance detection processing.

[0259] The imaging unit 12031 is a light sensor that receives light and outputs an electrical signal corresponding to the amount of light received. The imaging unit 12031 can output the electrical signal as an image or as distance measurement information. The light received by the imaging unit 12031 may be visible light or invisible light such as infrared light.

[0260] The in-vehicle information detection unit 12040 detects information inside the vehicle. The in-vehicle information detection unit 12040 is connected to, for example, a driver status detection unit 12041 that detects the driver's state. The driver status detection unit 12041 includes, for example, a camera that captures images of the driver, and the in-vehicle information detection unit 12040 may calculate the driver's level of fatigue or concentration, or determine whether the driver is drowsy, based on the detection information input from the driver status detection unit 12041.

[0261] The microcomputer 12051 can calculate control target values ​​for the drive force generator, steering mechanism, or braking device based on information inside and outside the vehicle acquired by the external information detection unit 12030 or the internal information detection unit 12040, and output control commands to the drive system control unit 12010. For example, the microcomputer 12051 can perform cooperative control aimed at realizing ADAS (Advanced Driver Assistance System) functions, including collision avoidance or impact mitigation, following driving based on distance between vehicles, maintaining vehicle speed, vehicle collision warning, or vehicle lane departure warning.

[0262] Furthermore, the microcomputer 12051 can perform cooperative control for purposes such as autonomous driving, where the vehicle drives autonomously without driver intervention, by controlling the drive force generating device, steering mechanism, or braking device, etc., based on information about the vehicle's surroundings acquired by the external information detection unit 12030 or the internal information detection unit 12040.

[0263] Furthermore, the microcomputer 12051 can output control commands to the body system control unit 12020 based on external information acquired by the external information detection unit 12030. For example, the microcomputer 12051 can control the headlights according to the position of a preceding or oncoming vehicle detected by the external information detection unit 12030, and perform coordinated control aimed at reducing glare, such as switching from high beams to low beams.

[0264] The audio-image output unit 12052 transmits at least one of audio and image output signals to an output device capable of visually or audibly notifying information to the vehicle's occupants or to those outside the vehicle. In the example shown in Figure 38, the output devices include an audio speaker 12061, a display unit 12062, and an instrument panel 12063. The display unit 12062 may include, for example, at least one of an onboard display and a head-up display.

[0265] Figure 39 shows an example of the installation position of the imaging unit 12031.

[0266] In Figure 39, the imaging unit 12031 includes imaging units 12101, 12102, 12103, 12104, and 12105.

[0267] The imaging units 12101, 12102, 12103, 12104, and 12105 are installed, for example, on the front nose, side mirrors, rear bumper, back door, and the upper part of the windshield inside the vehicle 12100. The imaging unit 12101 installed on the front nose and the imaging unit 12105 installed on the upper part of the windshield inside the vehicle mainly acquire images of the front of the vehicle 12100. The imaging units 12102 and 12103 installed on the side mirrors mainly acquire images of the sides of the vehicle 12100. The imaging unit 12104 installed on the rear bumper or back door mainly acquires images of the rear of the vehicle 12100. The imaging unit 12105 installed on the upper part of the windshield inside the vehicle is mainly used for detecting preceding vehicles, pedestrians, obstacles, traffic lights, traffic signs, or lanes.

[0268] Figure 39 shows an example of the imaging range of imaging units 12101 to 12104. Imaging range 12111 indicates the imaging range of imaging unit 12101 located on the front nose, imaging ranges 12112 and 12113 indicate the imaging ranges of imaging units 12102 and 12103 located on the side mirrors, respectively, and imaging range 12114 indicates the imaging range of imaging unit 12104 located on the rear bumper or back door. For example, by superimposing the image data captured by imaging units 12101 to 12104, an overhead view image of the vehicle 12100 can be obtained.

[0269] At least one of the imaging units 12101 to 12104 may have a function for acquiring distance information. For example, at least one of the imaging units 12101 to 12104 may be a stereo camera consisting of multiple image sensors, or an image sensor having pixels for phase difference detection.

[0270] For example, the microcomputer 12051, based on distance information obtained from the imaging units 12101 to 12104, can determine the distance to each object within the imaging range 12111 to 12114 and the temporal change of this distance (relative speed to the vehicle 12100). In particular, it can extract the closest object on the vehicle 12100's path that is traveling in approximately the same direction as the vehicle 12100 at a predetermined speed (e.g., 0 km / h or more) as the preceding vehicle. Furthermore, the microcomputer 12051 can set a predetermined distance to be maintained before the preceding vehicle and perform automatic braking control (including follow-and-stop control) and automatic acceleration control (including follow-and-start control), etc. In this way, cooperative control aimed at autonomous driving, where the vehicle drives autonomously without driver intervention, can be performed.

[0271] For example, the microcomputer 12051 can use distance information obtained from imaging units 12101 to 12104 to classify and extract three-dimensional object data related to three-dimensional objects, such as motorcycles, passenger cars, large vehicles, pedestrians, utility poles, and other three-dimensional objects, and use this data for automatic obstacle avoidance. For example, the microcomputer 12051 identifies obstacles around the vehicle 12100 into obstacles that are visible to the driver of the vehicle 12100 and obstacles that are difficult to see. The microcomputer 12051 then determines the collision risk, which indicates the degree of risk of collision with each obstacle. If the collision risk is above a set value and there is a possibility of collision, the microcomputer 12051 can provide driving assistance to avoid collisions by outputting a warning to the driver via the audio speaker 12061 or the display unit 12062, or by performing forced deceleration or evasive steering via the drive system control unit 12010.

[0272] At least one of the imaging units 12101 to 12104 may be an infrared camera that detects infrared light. For example, the microcomputer 12051 can recognize pedestrians by determining whether or not pedestrians are present in the images captured by the imaging units 12101 to 12104. Such pedestrian recognition is performed, for example, by a procedure to extract feature points from the images captured by the imaging units 12101 to 12104 as infrared cameras, and a procedure to perform pattern matching on a series of feature points that indicate the contour of an object to determine whether or not it is a pedestrian. When the microcomputer 12051 determines that a pedestrian is present in the images captured by the imaging units 12101 to 12104 and recognizes a pedestrian, the audio-image output unit 12052 controls the display unit 12062 to superimpose a rectangular contour line for emphasis on the recognized pedestrian. The audio-image output unit 12052 may also control the display unit 12062 to display an icon indicating a pedestrian at a desired position.

[0273] The above describes an example of a vehicle control system to which this technology may be applied. This technology can be applied to, for example, the imaging unit 12031 in the configuration described above.

[0274] The specific numerical values, shapes, materials (including composition), etc., described herein are examples only and are not limited to these.

[0275] Furthermore, this technology can also take the following configurations: [1] A light-emitting device comprising a surface light-emitting element and a light-receiving element, wherein the surface light-emitting element emits light in a predetermined direction, and the light-receiving element receives monitor light leaking in at least one direction different from the predetermined direction, and is smaller in size than the surface light-emitting element. [2] The light-emitting device according to [1], further comprising a substrate, wherein the substrate, the surface light-emitting element, and the light-receiving element are arranged in this order, wherein the surface light-emitting element emits light in the direction of the substrate, and the light-receiving element receives the monitor light leaking in the direction opposite to the direction of the substrate. [3] The light-emitting device according to [1] or [2], wherein the light-receiving elements are arranged in an array, and a plurality of monitor lights leaking in at least one direction different from the direction of light emission, corresponding to a plurality of light emission points, can be individually monitored. [4] The light-emitting device according to any one of [1] to [3], wherein the surface light-emitting element is a photonic crystal laser, and the light-receiving element is arranged to correspond to the light-emitting points in order to monitor a plurality of monitor lights leaking from a plurality of light-emitting points of the photonic crystal laser in at least one direction different from the direction of light emission. [5] The light-emitting device according to any one of [1] to [4], wherein the light-receiving element is arranged in a direction perpendicular to the direction of light emission and receives monitor light leaking in the direction perpendicular. [6] The light-emitting device according to any one of [1] to [5], wherein the light-receiving element is arranged in a direction opposite to and perpendicular to the direction of light emission and receives monitor light leaking in the opposite and perpendicular directions. [7] The light-emitting device according to any one of [1] to [6], further comprising a laser driver, wherein the light-receiving element formed in the laser driver receives monitor light leaking through an opening provided on the laser driver side of the surface light-emitting element. [8] The light-emitting device according to any one of [1] to [7], wherein the light-receiving element is a PIN-type photodiode or an avalanche photodiode.[9] The light-emitting device according to any one of [1] to [8], wherein a transimpedance amplifier is added to the photodetector, and the transimpedance amplifier converts the current signal generated by the photodetector into a voltage signal.

[10] The light-emitting device according to any one of [1] to [9], wherein the surface light-emitting element is a vertical resonator surface-emitting laser.

[11] The light-emitting device comprising: a difference detection unit that detects the difference between input / output signals corresponding to each of a plurality of light-emitting elements and a reference value; an event generation unit that generates an event based on the result of comparing the difference with a predetermined threshold; and an output unit that outputs event information including identification information that identifies the light-emitting element that is the source of the generated event.

[12] The light-emitting device according to

[11] , wherein the identification information includes at least one of coordinates for identifying the light-emitting element that is the source of the event, the time of the event, and the polarity of the event.

[13] The light-emitting device according to

[11] or

[12] , wherein the difference detection unit has a configuration that asynchronously detects the difference between input / output signals and a reference value.

[14] The light-emitting device according to any one of

[11] to

[13] , wherein the amplifier provided in the difference detection unit has a configuration that increases the gain when the difference between the input / output signal and a reference value is small, and decreases the gain when the difference is large.

[15] The light-emitting device according to any one of

[11] to

[14] , further comprising an arbitration circuit for arbitrating events related to each of a plurality of light-emitting elements in the order in which they occur and outputting them sequentially.

[16] The light-emitting device according to any one of

[11] to

[15] , further comprising a photodetector for receiving the light emitted from the light-emitting element, wherein the output unit outputs the event information based on the signal from the photodetector and the events generated by the event generation unit.

[17] The light-emitting device according to any one of

[11] to

[16] , further comprising a control unit for controlling the drive current or temperature of the light-emitting element based on the event information.

[18] The light-emitting device according to any one of

[11] to

[17] , further comprising a laser driver, wherein the light-emitting element, the laser driver, and the difference detection unit are stacked in this order and electrically connected to each other.

[19] The light-emitting device according to

[18] , further comprising a photodetector that receives light emitted from the light-emitting element, wherein the output unit outputs event information based on the signal from the photodetector and the event generated by the event generation unit.

[20] The light-emitting device according to any one of

[11] to

[19] , wherein the light-emitting element has a back-side emission structure that emits light toward the substrate.

[21] A distance measuring device comprising the light-emitting device according to any one of [1] to

[20] .

[22] An electronic device comprising the distance measuring device according to

[21] .

[23] A method for manufacturing a light-emitting device, comprising: forming a surface light-emitting element; configuring the surface light-emitting element to emit light in a predetermined direction; and arranging a photodetector that is smaller in size than the surface light-emitting element and receives monitor light that leaks in at least one direction different from the direction of light emission.

[24] A method for sensing light-emitting elements, comprising: detecting the difference between an input / output signal corresponding to each of a plurality of light-emitting elements and a reference value; generating an event based on the result of comparing the difference with a predetermined threshold; and outputting event information including identification information that identifies the light-emitting element that is the source of the generated event.

[0276] 10 Signal processing unit 11 Difference detection unit 111 Amplifier 12 Event generation unit 121 Comparator 13 Output unit 14 Arbitration circuit 16 Transimpedance amplifier 17 Bandpass filter 18 Control unit 100 Surface light-emitting element, light-emitting element, photonic crystal surface light-emitting laser 101 Substrate 107 DBR layer 200 Laser driver 201 Aperture 202 TIA circuit 300 Photodetector 1000 Light-emitting device

Claims

1. A light-emitting device comprising a surface light-emitting element and a light-receiving element, wherein the surface light-emitting element emits light in a predetermined direction, and the light-receiving element receives monitor light leaking in at least one direction different from the predetermined direction, and is smaller in size than the surface light-emitting element.

2. The light-emitting device according to claim 1, further comprising a substrate, wherein the substrate, the surface light-emitting element, and the light-receiving element are arranged in this order, the surface light-emitting element emits light toward the substrate, and the light-receiving element receives the monitor light leaking toward the opposite direction from the substrate.

3. The light-emitting device according to claim 1, wherein the light-receiving elements are arranged in an array, and a plurality of monitor lights leaking in at least one direction different from the direction of light emission, corresponding to a plurality of light emission points, can be individually monitored.

4. The light-emitting device according to claim 1, wherein the surface light-emitting element is a photonic crystal laser, and the light-receiving elements are arranged to correspond to the light-emitting points in order to monitor a plurality of monitor lights leaking from a plurality of light-emitting points of the photonic crystal laser in at least one direction different from the direction of light emission.

5. The light-emitting device according to claim 1, wherein the light-receiving element is arranged in a direction perpendicular to the direction of light emission and receives monitor light leaking in the direction perpendicular to the light emission direction.

6. The light-emitting device according to claim 1, wherein the light-receiving element is arranged in a direction opposite to and perpendicular to the direction of light emission, and receives monitor light leaking in the opposite and perpendicular directions.

7. The light-emitting device according to claim 1, further comprising a laser driver, wherein a light-receiving element formed on the laser driver receives monitor light leaking through an opening provided on the laser driver side of the surface light-emitting element.

8. The light-emitting device according to claim 1, wherein the light-receiving element is a PIN-type photodiode or an avalanche photodiode.

9. The light-emitting device according to claim 1, wherein a transimpedance amplifier is added to the light-receiving element, and the transimpedance amplifier converts the current signal generated by the light-receiving element into a voltage signal.

10. The light-emitting device according to claim 1, wherein the surface light-emitting element is a vertical cavity surface-emitting laser.

11. A light-emitting device comprising: a difference detection unit that detects the difference between the input / output signals corresponding to each of a plurality of light-emitting elements and a reference value; an event generation unit that generates an event based on the comparison result of the difference with a predetermined threshold; and an output unit that outputs event information including identification information that identifies the light-emitting element that is the source of the generated event.

12. The light-emitting device according to claim 11, wherein the identification information includes at least one of the coordinates for identifying the light-emitting element that caused the event, the time of the event, and the polarity of the event.

13. The light-emitting device according to claim 11, wherein the difference detection unit has a configuration that asynchronously detects the difference between an input / output signal and a reference value.

14. The light-emitting device according to claim 11, wherein the amplifier provided in the difference detection unit has a configuration that increases the gain when the difference between the input / output signal and the reference value is small, and decreases the gain when the difference is large.

15. The light-emitting device according to claim 11, further comprising an arbitration circuit for arbitrating events associated with each of a plurality of light-emitting elements in the order in which they occur and outputting them sequentially.

16. The light-emitting device according to claim 11, further comprising a light-receiving element that receives light emitted from the light-emitting element, wherein the output unit outputs event information based on the signal from the light-receiving element and the event generated by the event generation unit.

17. The light-emitting device according to claim 11, further comprising a control unit that controls the drive current or temperature of the light-emitting element based on the event information.

18. The light-emitting device according to claim 11, further comprising a laser driver, wherein the light-emitting element, the laser driver, and the difference detection unit are stacked in this order and electrically connected to one another.

19. The light-emitting device according to claim 18, further comprising a light-receiving element that receives light emitted from the light-emitting element, wherein the output unit outputs event information based on the signal from the light-receiving element and the event generated by the event generation unit.

20. The light-emitting device according to claim 11, wherein the light-emitting element has a back-side emission type structure that emits light in the direction of the substrate.

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