Light-emitting and detecting devices

Abstract

To make light rise faster than in a configuration in which a storage element is provided in a resonance circuit without being limited.SOLUTION: A light emitting device includes a substrate provided with at least a part of a resonance circuit that generates resonance, and a light-emitting element that emits light when supplied with a current in a resonance circuit, and the substrate includes an electric storage layer that is provided in the resonance circuit and stores electric charges, and the resonance circuit is not provided with an electric storage element that is thicker than the electric storage layer and stores electric charges.SELECTED DRAWING: Figure 3

Description

[Technical Field]

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

[0002] Patent Document 1 describes that in the light emitting device, a general-purpose (normal) capacitor is further connected to a series circuit of a light emitting element and a transistor. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 2020-188239 Summary of the Invention [Problem to be solved by the invention]

[0004] There is a technology in which a storage element that stores electric charge supplies a current to a light-emitting element, causing the light-emitting element to emit light. Also, a storage element may be provided in a resonant circuit where resonance occurs, and the current in the resonant circuit may be supplied to the light-emitting element. In this case, if the storage element is provided in the resonant circuit without any restrictions, the slope of the rising edge of the light may become gentler depending on the storage element provided, due to the capacitance and inductance of the storage element. An object of the present invention is to make the light rise faster than in a configuration in which the storage element is provided in a resonant circuit without any restrictions. [Means for solving the problem]

[0005] The invention described in claim 1 is a resonant circuit in which resonance occurs. The road and a substrate on which the resonant circuit is provided. When the resonant circuit is turned on, resonance occurs. The current , through a storage layer including a storage element that stores electric charge. a light emitting element that emits light when supplied with light; a suppression means connected to a circuit between a power source that supplies electric charge to the storage layer and the resonant circuit, and that suppresses charge transfer between the power source and the resonant circuit; Equipped with ,before The resonant circuit includes the storage layer The energy storage element that constitutes than In the vertical directionLarge thickness allows for electrical charge storage other A storage element is provided The suppression means is a resistor, and the resistor has a predetermined electrical resistance that is large enough to suppress attenuation of resonance due to the influence of the power source when resonance occurs in the resonant circuit. The light emitting device is characterized by the above. The invention described in claim 2 is a light-emitting device comprising: a substrate on which a resonant circuit that generates resonance is provided; a light-emitting element that emits light when the current generated by the resonant circuit being conductive and causing resonance is supplied through a storage layer including a storage element that stores charge; and a suppression means connected to a circuit between the resonant circuit and a power source that supplies charge to the storage layer, and that suppresses charge transfer between the power source and the resonant circuit; wherein the resonant circuit does not have any other storage elements that store charge and are thicker in the vertical direction than the storage elements that constitute the storage layer; the suppression means is a transistor; and a voltage of a magnitude that would cause the circuit between the power source and the resonant circuit to be conductive when resonance is occurring in the resonant circuit is not applied to the transistor. Claim 3 The invention described in claim 1 or 2 a light-receiving means for receiving light based on irradiation of an object with light emitted from the light-emitting device; and a detecting means for detecting a distance to the object based on reception of the light by the light-receiving means, wherein the storage layer has a dielectric layer that is a dielectric material, and the dielectric layer has an area of ​​10 -7 m 2 Over 10 -3 m 2 and the thickness is 5×10 -7 m or more 10 -4 m or less, and the relative dielectric constant is 3 to 10 4 and the distance to the object is within a range of 0.1 m to 500 m. Claim 4 The invention described in the above item is characterized in that the dielectric layer has an area of ​​10 -6 m 2 Over 10 -4 m 2 The thickness is 10 -6 m or more 5×10 -5 m or less, and the relative dielectric constant is 3 to 10 3 The present invention is characterized in that: 3 The detection device described 。 request request 5 The invention described in claim 1 is characterized in that the substrate has a plurality of layers including the storage layer, and the light emitting element is provided so as to overlap the plurality of layers. or 2 The light emitting device is as described above. Claim 6 The invention described in the item (1) is characterized in that the plurality of layers include a layer provided in the resonant circuit and through which a current supplied to the light emitting element passes. 5 The light emitting device is as described above. Claim 7 The invention described in The road and a substrate on which the resonant circuit is provided. When the resonant circuit is turned on, resonance occurs. The current , through a storage layer including a storage element that stores electric charge. a light emitting element that emits light when supplied with light; a suppression means connected to a circuit between a power source that supplies electric charge to the storage layer and the resonant circuit, and that suppresses charge transfer between the power source and the resonant circuit; The substrate has a capacitance of 10 -11 F or above 10 -9 F or less, and a dielectric layer that is a dielectric, and a storage layer that is provided in the resonance circuit. The suppression means is a resistor, and the resistor has a predetermined electrical resistance that is large enough to suppress attenuation of resonance due to the influence of the power source when resonance occurs in the resonant circuit. The light emitting device is characterized by the above. The invention described in claim 8 is a light-emitting element that emits light when a current generated by the resonance circuit being conductive and causing resonance is supplied via a power storage layer including a power storage element that stores electric charge, and a suppression means that is connected to a circuit between a power source that supplies electric charge to the power storage layer and the resonance circuit and that suppresses charge transfer between the power source and the resonance circuit, wherein the substrate has a capacitance of 10 -11 F or above 10 -9 The light-emitting device has a storage layer provided in the resonant circuit, the storage layer having a dielectric layer of dielectric material having a capacitance of F or less, the suppression means being a transistor, and a voltage of a magnitude that would cause a circuit between the power source and the resonant circuit to be conductive is not applied to the transistor when resonance occurs in the resonant circuit. [Effects of the Invention]

[0006] According to the invention of claim 1, the rise of light can be made faster compared to a configuration in which the power storage element is provided in the resonant circuit without any restrictions. Furthermore, compared to a configuration in which the light emitting device is not provided with a suppressing means, it is possible to suppress the attenuation of resonance in the resonant circuit. According to the invention of claim 2, the rise of light can be made faster compared to a configuration in which the storage element is provided in the resonant circuit without any restrictions. Also, the attenuation of resonance in the resonant circuit can be suppressed compared to a configuration in which the light emitting device is not provided with a suppression means. Also, resonance can be more easily generated in the resonant circuit compared to a configuration in which the suppression means does not interrupt conduction in the circuit. Claim 3 According to this invention, the rise of light can be made faster in a detection device that detects distances of 0.1 m or more and 500 m or less, compared to a configuration in which a storage element is provided in a resonant circuit without any restrictions. Claim 4 According to this invention, light can be read most efficiently. request request 5 According to the invention, the electric path in the resonant circuit can be made shorter than in a configuration in which the light emitting element is provided so as not to overlap the electricity storage layer. Claim 6 According to the invention, the electric path in the resonant circuit can be made shorter than in a configuration in which the light emitting element is provided so as not to overlap with a layer through which a current supplied to the light emitting element passes. Claim 7 According to the invention, the light can be made to rise faster than in a configuration in which the storage element is provided in the resonant circuit without any restrictions. Furthermore, compared to a configuration in which the light emitting device is not provided with a suppressing means, it is possible to suppress the attenuation of resonance in the resonant circuit. According to the invention of claim 8, the light rise can be made faster compared to a configuration in which the storage element is provided in the resonant circuit without any restrictions. Also, the attenuation of resonance in the resonant circuit can be suppressed compared to a configuration in which the light emitting device is not provided with a suppression means. Also, resonance can be made to occur more easily in the resonant circuit compared to a configuration in which the suppression means does not interrupt conduction in the circuit. [Brief explanation of the drawings]

[0007] [Figure 1] FIG. 1 is a diagram illustrating an example of the configuration of a detection device. [Figure 2] FIG. 1 is a cross-sectional view of a light emitting device. [Figure 3] 1A is a perspective view of the light emitting device, and FIG. 1B is a view of the light emitting device viewed from the left side of the light emitting device. [Figure 4] FIG. 2 is a diagram showing an electronic circuit of the light-emitting device. [Figure 5] 10 is a diagram showing the relationship between the time elapsed since the light emitting device started to emit light and the intensity of emitted light. [Figure 6] FIG. 10 is a diagram showing an electronic circuit of a modified light-emitting device. [Figure 7] (a) is a diagram showing parameters for the detection device, (b) is a diagram showing the relationship between the relative permittivity, length, and thickness for the dielectric layer to satisfy a capacitance of approximately 10 pF, and (c) is a diagram showing the relationship between the relative permittivity, length, and thickness for the dielectric layer to satisfy a capacitance of approximately 1000 pF. DETAILED DESCRIPTION OF THE INVENTION

[0008] Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. FIG. 1 is a diagram showing an example of the configuration of a detection device 1. The detection device 1 is a device that detects the distance from the detection device 1 to an object. The object to which the detection device 1 detects the distance is hereinafter referred to as object T. In this embodiment, LiDAR (Light Detection and Ranging) is used as a method for the detection device 1 to detect the distance to the object T. LiDAR measures the distance to the object T by detecting light. There are two types of LiDAR: scanning LiDAR that scans light, and batch irradiation LiDAR that irradiates light all at once within a predetermined angular range. In this embodiment, the distance to the object T is detected by scanning LiDAR.

[0009] Furthermore, LiDAR uses TOF (Time Of Flight). TOF is the measurement of the distance to the target T based on the time it takes for light to travel. There are two types of TOF: iTOF (indirect Time Of Flight) and dTOF (direct Time Of Flight). iTOF is a method of measuring the distance to the target T from the difference between the phase of emitted light and the phase of received light. Furthermore, dTOF is a method of measuring the distance to the target T based on the time from when light is emitted to when it is received. The detection device 1 includes a light emitting device 10, a light receiving unit 20, and a detection unit 30.

[0010] The light emitting device 10 is a device that emits light. An example of the light emitting device 10 is a VCSEL (Vertical Cavity Surface Emitting Laser). A VCSEL is a laser that emits light in a direction perpendicular to the surface of a substrate. The light emitting device 10 of this embodiment generates a pulsed current by resonance and emits light using the generated current. The configuration of the light emitting device 10 will be described in detail later.

[0011] The light receiving unit 20, which is an example of a light receiving means, receives light based on the irradiation of the object T with light emitted from the light emitting device 10. When the light receiving unit 20 receives light, it generates an electric charge. Examples of light based on the irradiation of the object T with light emitted from the light emitting device 10 include light emitted from the light emitting device 10 and reflected by the object T, and light emitted from the light emitting device 10 and scattered by the object T. Hereinafter, the light emitted from the light emitting device 10 may be referred to as emitted light. Hereinafter, the light emitted from the light emitting device 10 and reflected by the object T will be referred to as reflected light. Hereinafter, the light emitted from the light emitting device 10 and scattered by the object T will be referred to as scattered light. An optical sensor that detects light is an example of the light receiving unit 20. An example of the optical sensor is a semiconductor such as a SPAD (Single Photon Avalanche Diode).

[0012] The detection unit 30, which is an example of a detection means, detects the distance from the detection device 1 to the target object T based on the light received by the light receiving unit 20. The detection unit 30 has a timing unit 31 and a measurement unit 32. The timing unit 31 keeps time. The measurement unit 32 acquires information indicating the time from when light is emitted from the light-emitting device 10 to when the light-receiving unit 20 generates an electric charge from the timer unit 31. Then, based on the acquired information, the measurement unit 32 measures the distance from the detection device 1 to the object T. More specifically, the measurement unit 32 measures the distance from the detection device 1 to the object T using the following formula (1). TIFF0007739899000001.tif26167

[0013] In equation (1), L is the distance from the detection device 1 to the object T. Furthermore, c is the speed of light. Furthermore, t is the time from when light is emitted from the light-emitting device 10 until when the light-receiving unit 20 generates an electric charge. In addition, the measurement unit 32 measures the distance from the detection device 1 to the object T by calculating the time from when light is emitted from the light-emitting device 10 until when the light-receiving unit 20 generates an electric charge as the time from when light is emitted from the light-emitting device 10 until when the light-receiving unit 20 receives the light.

[0014] The detection device 1 is provided on a moving vehicle 2. In the illustrated example, the vehicle 2 is an automobile. Note that the vehicle 2 is not limited to the illustrated example. The vehicle 2 may be, for example, a drone, a train, a ship, an airplane, etc. Furthermore, the vehicle 2 may be a computer carried by a user of the detection device 1. In addition, in the illustrated example, a human is shown as the object T, but the object T is not limited to a human. The object T may be any object that reflects light emitted from the light-emitting device 10 or scatters light when irradiated with light emitted from the light-emitting device 10. Furthermore, the detection device 1 of this embodiment includes a distance to the object T of 0.1 m or more and 500 m or less as a detection target.

[0015] Next, the configuration of the light emitting device 10 will be described. FIG. 2 is a cross-sectional view of the light emitting device 10. In FIG. 2, the upper side of the light emitting device 10 on the paper surface is referred to as the "upper side," the lower side of the paper surface is referred to as the "lower side," and these directions are sometimes referred to as the "vertical direction." Furthermore, the left side of the light emitting device 10 on the paper surface is referred to as the "left side," and the right side of the light emitting device 10 on the paper surface is referred to as the "right side," and these directions are sometimes referred to as the "horizontal direction." Furthermore, the front side of the light emitting device 10 on the paper surface is referred to as the "front side," and the rear side of the paper surface is referred to as the "rear side," and these directions are sometimes referred to as the "front-rear direction." FIG. 3(a) is a perspective view of the light-emitting device 10, and FIG. 3(b) is a view of the light-emitting device 10 viewed from the left side of the light-emitting device 10. FIG. 2 is a cross-sectional view taken along line II-II in FIG. 3(b). FIG. 3(a) shows the light-emitting device 10 in an exploded state for ease of explanation. FIG. 3(a) omits the middle electrical path layer 133, the lower electrical path layer 134, the upper insulating layer 135, the reinforcing layer 136, and the lower insulating layer 137, which will be described later, for ease of explanation. FIG. 3(b) omits the middle electrical path layer 133, the lower electrical path layer 134, the reinforcing layer 136, and the lower insulating layer 137, which will be described later, for ease of explanation.

[0016] As shown in FIG. 2, the light emitting device 10 includes a light emitting element 11, an actuation portion 12, and a substrate 13. The light emitting element 11 is an element that emits light when a current is supplied to it. The light emitting element 11 emits light upward, which is perpendicular to the surface of the substrate 13. The light emitting element 11 is provided with an anode surface 11A and a cathode surface 11B. The anode surface 11A is the top surface of the light emitting element 11, and is the surface on which the anode is formed. The cathode surface 11B is the bottom surface of the light emitting element 11, and is the surface on which the cathode is formed.

[0017] The operating section 12 is an integrated circuit (IC) that operates the light emitting element 11. The operating section 12 is provided with a cathode terminal 121, a ground terminal 122, and a solder section 123. The cathode terminal 121 is a terminal that forms the cathode. The ground terminal 122 is a terminal that forms a ground, which is an electric path that serves as a reference potential in an electronic circuit. The solder portion 123 is solder that adheres to the substrate 13 .

[0018] The substrate 13 is a substrate on which part of a resonant circuit is provided. A resonant circuit is an electronic circuit in which resonance occurs. The substrate 13 has multiple layers. More specifically, the substrate 13 has an upper electrical path layer 131, a capacitor layer 132, a middle electrical path layer 133, a lower electrical path layer 134, an upper insulating layer 135, a reinforcing layer 136, and a lower insulating layer 137.

[0019] The upper electrical path layer 131 is a layer that forms an electrical path. The upper electrical path layer 131 is provided on the uppermost side of the substrate 13. The cathode terminal 121 of the operating section 12 is attached to the upper electrical path layer 131. The capacitor layer 132, which is an example of a storage layer, is a layer that stores electric charges. That is, the capacitor layer 132 is a storage element that stores electric charges. The capacitor layer 132 supplies electric current to the light-emitting element 11 by discharging the stored electric charges. The capacitor layer 132 is provided below the upper electrical path layer 131 on the substrate 13.

[0020] The intermediate current path layer 133 is a layer that forms an electric path. The intermediate current path layer 133 is provided below the capacitor layer 132 on the substrate 13. The lower electrical path layer 134 is a layer that forms an electrical path. The lower electrical path layer 134 is provided on the lowermost side of the substrate 13. Both the middle electrical path layer 133 and the lower electrical path layer 134 are made of a metal material, such as copper.

[0021] The upper insulating layer 135 is a layer that insulates the upper electrical path layer 131 from the capacitor layer 132. The upper insulating layer 135 is provided between the upper electrical path layer 131 and the capacitor layer 132 in the vertical direction. The ground terminal 122 and the solder portion 123 of the actuation portion 12 are attached to this upper insulating layer 135. The reinforcing layer 136 is a layer that supplements the strength of the substrate 13. The reinforcing layer 136 also insulates the capacitor layer 132 from the intermediate electric path layer 133. The reinforcing layer 136 is provided between the capacitor layer 132 and the intermediate electric path layer 133 in the vertical direction. The lower insulating layer 137 is a layer that insulates the intermediate electrical path layer 133 from the lower electrical path layer 134. The lower insulating layer 137 is provided between the intermediate electrical path layer 133 and the lower electrical path layer 134 in the vertical direction. Upper insulating layer 135, reinforcing layer 136, and lower insulating layer 137 are made of, for example, prepreg, which is a material in which carbon fibers are pre-impregnated with resin.

[0022] In this embodiment, the ground terminal 122 of the actuation unit 12 is connected to the capacitor layer 132 through a via V. A via is an opening for providing electrical continuity between one end and the other end. The inner circumferential surface of this opening is coated with a metal material, thereby providing electrical continuity between the one end and the other end. In this embodiment, the via V is provided in the upper insulating layer 135, thereby providing electrical continuity between the ground terminal 122 and the capacitor layer 132.

[0023] As shown in FIGS. 3(a) and 3(b), the upper electrical path layer 131 is provided with a cathode layer 1311 and an anode layer 1312. The cathode layer 1311 is a layer that forms a cathode. The cathode surface 11B of the light-emitting element 11 is attached to the cathode layer 1311. More specifically, the entire cathode surface 11B is attached to the cathode layer 1311. The cathode layer 1311 is formed longer in the left-right direction than the light-emitting element 11, and there is a portion of the cathode layer 1311 to the right of the light-emitting element 11 where the cathode surface 11B is not attached. The cathode terminal 121 of the operating section 12 is attached to the portion of the cathode layer 1311 where the cathode surface 11B is not attached (see FIG. 2). In addition, four cathode terminals 121 are provided at equal intervals in the front-rear direction in the operating section 12, and these four cathode terminals 121 are attached to the cathode layer 1311 of the upper electrical path layer 131.

[0024] The anode layer 1312 is a layer that forms an anode. The anode layer 1312 is provided on both the front and rear sides of the cathode layer 1311. The anode layer 1312 is formed to be shorter in the left-right direction than the cathode layer 1311. More specifically, the anode layer 1312 is formed to have the same length in the left-right direction as the light-emitting element 11. Furthermore, the position of the anode layer 1312 in the left-right direction is aligned with the position of the light-emitting element 11. The anode surface 11A of the light-emitting element 11 and the anode layer 1312 are connected by wires W made of a metal material. In the illustrated example, five wires W are connected to the anode layer 1312 provided in front of the cathode layer 1311 and the anode layer 1312 provided behind the cathode layer 1311, respectively. The cathode layer 1311 and the anode layer 1312 are made of a metal material, such as copper.

[0025] The capacitor layer 132 is provided with a ground layer 1321, a dielectric layer 1322, and an anode layer 1323. The ground layer 1321, the dielectric layer 1322, and the anode layer 1323 are all formed in a rectangular shape. The ground layer 1321 is a layer that forms the ground. The ground terminal 122 of the actuation unit 12 is connected to the ground layer 1321 of the capacitor layer 132 through a via V (see FIG. 2). Although not shown, the actuation unit 12 is provided with four ground terminals 122 at equal intervals in the front-rear direction, and these four ground terminals 122 are each connected to the ground layer 1321 through a via V. The ground layer 1321 is made of a metal material. An example of the metal material is copper.

[0026] The dielectric layer 1322 is a layer that forms a dielectric. In this embodiment, Faradflex (registered trademark) manufactured by Oak-Mitsui Corporation is used as the dielectric layer 1322. In this embodiment, the thickness of the dielectric layer 1322 in the up-down direction is thickness d (see FIG. 2). The length of the dielectric layer 1322 in the front-rear direction is length a (see FIG. 3(a)). The length of the dielectric layer 1322 in the left-right direction is length b. The area of ​​the dielectric layer 1322 is the product of length a and length b. In this embodiment, the area of ​​the dielectric layer 1322 is equal to the area of ​​the ground layer 1321 and the area of ​​the anode layer 1323.

[0027] The anode layer 1323 is a layer that forms an anode. As shown in FIG. 3( a), the anode layer 1323 of the capacitor layer 132 is connected to the anode layer 1312 of the upper electrical path layer 131 through vias V. In this embodiment, vias V are provided in the upper insulating layer 135, the ground layer 1321 of the capacitor layer 132, and the dielectric layer 1322, thereby electrically connecting the anode layer 1312 of the upper electrical path layer 131 and the anode layer 1323 of the capacitor layer 132. In the illustrated example, four vias V are provided for each anode layer 1312 of the upper electrical path layer 131. These four vias V are provided at equal intervals in the left-right direction. The anode layer 1323 is made of a metal material, such as copper.

[0028] As shown in FIG. 3(a), the light emitting device 10 is also provided with a power supply 14 and a resistor 15. The power supply 14 supplies an electric charge to the capacitor layer 132 of the substrate 13. One end of the power supply 14 is connected to the resistor 15, and the other end is connected to the ground layer 1321 of the capacitor layer 132. The resistor 15, which is an example of a suppression means, has a predetermined electrical resistance. One end of the resistor 15 is connected to the power supply 14, and the other end is connected to the anode layer 1312 of the upper electrical path layer 131. That is, the resistor 15 is connected to the electrical path between the power supply 14 and the capacitor layer 132. In this embodiment, charge transfer between the power supply 14 and the resonant circuit RC is restricted depending on the electrical resistance of the resistor 15. More specifically, the higher the electrical resistance of the resistor 15, the more difficult it is for charge to transfer between the power supply 14 and the resonant circuit RC.

[0029] FIG. 4 is a diagram showing the electronic circuit of the light emitting device 10. As shown in FIG. As shown in Fig. 4, the electronic circuit of the light-emitting device 10 includes a resonant circuit RC. The resonant circuit RC of this embodiment includes a light-emitting element 11, an actuation unit 12, and a capacitor layer 132. Although not shown, in the resonant circuit RC, an anode layer 1312 of an upper electrical path layer 131 is connected to an electrical path between the light-emitting element 11 and the capacitor layer 132. In the resonant circuit RC, a cathode layer 1311 of an upper electrical path layer 131 is connected to an electrical path between the light-emitting element 11 and the actuation unit 12.

[0030] The actuator 12 includes a transistor 124. The transistor 124 is an electronic switch that switches between a conductive state and a non-conductive state of the resonant circuit RC depending on the applied voltage. When a voltage equal to or greater than a predetermined value is not applied to the transistor 124, the transistor 124 is in an OFF state. In this case, the circuit to which the transistor 124 is connected is disconnected, and the resonant circuit RC is not conductive, so no current is supplied to the light-emitting element 11. When a voltage equal to or greater than a predetermined value is applied to the transistor 124, the transistor 124 is in an ON state. In this case, the circuit to which the transistor 124 is connected is connected, and the resonant circuit RC is conductive. In this state, the impedance of the resonant circuit RC decreases at a specific frequency, causing resonance, and a pulsed current generated by this resonance is supplied to the light-emitting element 11. Note that the specific frequency, i.e., the frequency at which resonance occurs, may be referred to as the resonant frequency hereinafter. Note that the pulsed current may be simply referred to as a pulse hereinafter. Furthermore, a resistor 15 is connected to the electrical path between the power supply 14 and the resonant circuit RC.

[0031] In this embodiment, when the transistor 124 is in the OFF state, an electric charge is supplied from the power supply 14 to the capacitor layer 132 via the resistor 15, and a voltage is applied to the capacitor layer 132. In other words, the capacitor layer 132 is charged. Furthermore, when the transistor 124 is in the ON state, the capacitor layer 132 releases charge and a current is supplied from the capacitor layer 132 to the light-emitting element 11, causing the light-emitting element 11 to emit light. Furthermore, when the capacitor layer 132 releases charge, the transistor 124 again becomes OFF, and the capacitor layer 132 is charged. In this way, in this embodiment, charging of the capacitor layer 132 and supply of a current from the capacitor layer 132 to the light-emitting element 11, causing the light-emitting element 11 to emit light, are repeated.

[0032] As described above, the light-emitting device 10 of this embodiment generates pulses by resonance at a specific frequency and supplies the generated pulses to the light-emitting element 11, causing the light-emitting element 11 to emit light. Here, in dTOF, which is a type of TOF described above, it is not necessary to have a wide frequency range for generating current; it is sufficient to generate current by lowering the impedance in the electronic circuit at a single frequency. In contrast, in iTOF, current must be generated over a wider frequency range than in dTOF, and therefore the impedance in the electronic circuit must be low over this wide frequency range. Therefore, the light-emitting device 10 of this embodiment is suitable for use as a light source for dTOF, due to its property of generating pulses by resonance by lowering the impedance in the resonant circuit RC at a single resonant frequency. However, the light-emitting device 10 may also be used as a light source for iTOF.

[0033] Furthermore, the light emitting device 10 is required to shorten the time from when light emission starts until the intensity of the emitted light increases, that is, to speed up the rise in the intensity of the emitted light. Fig. 5 is a diagram showing the relationship between the time elapsed since the light emitting device 10 started to emit light and the intensity of the emitted light. Note that the intensity of the emitted light has a waveform that is even sharper than the waveform shown in Fig. 5 due to a time delay in the rising edge caused by the effect of relaxation oscillation, but Fig. 5 shows the intensity of the emitted light when the effect of relaxation oscillation is not taken into consideration. In FIG. 5, the horizontal axis represents the time elapsed since the light emitting device 10 started emitting light, and the vertical axis represents the intensity of the emitted light Li. In addition, for the emitted light Li shown in FIG. 5, the angle at which the rise in intensity of the emitted light Li inclines over time is angle θ. Note that, hereinafter, the rise in light intensity may be simply referred to as the rise in light. Furthermore, the angle θ at which the rise in emitted light inclines over time may be referred to as the tilt angle θ.

[0034] As described above, the detection device 1 of this embodiment detects the distance to the object T based on the time from when light emission begins to when reflected light or scattered light is received. Here, the lower limit of the intensity of emitted light required to generate reflected light is determined by the reflectance of light on the object T. More specifically, the higher the reflectance of light on the object T, the lower the lower limit of the intensity of emitted light required to generate reflected light. Note that the reflectance of light is the ratio between the intensity of emitted light and the intensity of reflected light. The reflectance of light is determined for each object T. Here, the intensity C1 shown in Fig. 5 is the lower limit of the intensity of the output light Li required to generate reflected light from an object O1 with a specific light reflectance. Also, the intensity C2 shown in Fig. 5 is the lower limit of the intensity of the output light Li required to generate reflected light from an object O2 with a lower light reflectance than the object O1. Hereinafter, the lower limit of the intensity of the output light Li required to generate reflected light may be referred to as the light lower limit.

[0035] When the detection device 1 irradiates the object O1 with the emitted light Li, light having an intensity of the lower limit C1 is emitted when time T1 has elapsed since the detection device 1 started emitting light. When the detection device 1 irradiates the object O2 with the emitted light Li, light having an intensity of the lower limit C2 is emitted when time T2 has elapsed since the detection device 1 started emitting light. Here, when the object irradiated with the emitted light Li is the object O2, the time from when the detection device 1 starts emitting light to when light having an intensity of the lower limit is emitted is longer than when the object O1 is irradiated with the emitted light. Furthermore, as the time from when the detection device 1 starts emitting light to when light having an intensity of the lower limit is emitted becomes longer, the time from when the detection device 1 starts emitting light to when it receives reflected light also becomes longer. In this case, even if the distance from the detection device 1 to the object O1 and the distance from the detection device 1 to the object O2 are the same, the time from when the detection device 1 starts emitting light to when it receives reflected light is longer for the object O2 than for the object O1 by the difference between time T1 and time T2. In other words, the time from when the detection device 1 starts emitting light until light whose intensity is the lower light limit is emitted varies depending on the reflectance of the object T, and this variation in time also causes variation in the result detected as the distance from the detection device 1 to the object T. Therefore, it is preferable that the variation for each object T in the time from when the detection device 1 starts emitting light until light whose intensity is the lower light limit is emitted is small.

[0036] Furthermore, as the tilt angle θ becomes gentler, that is, as the rise of the emitted light Li becomes slower, the time from when the detection device 1 starts to emit light until light whose intensity is the lower light limit is emitted varies more for each object T, such that the difference between time T1 and time T2 becomes larger. Furthermore, as the rise of light becomes faster, the time from when the detection device 1 starts to emit light until light whose intensity is the lower light limit is emitted varies less for each object T, such that the difference between time T1 and time T2 becomes smaller. Furthermore, the intensity of the emitted light increases as the current supplied to the light-emitting element 11 increases, and the faster the rise of the current in the light-emitting device 10, the faster the rise of the emitted light. Therefore, when the rise of the current in the light-emitting device 10 is faster, the variation for each object T in the time from when the detection device 1 starts to emit light until light whose intensity is the light lower limit value is emitted decreases.

[0037] In this embodiment, the resonant circuit RC generates pulses by resonance, which have a shorter pulse width and a faster rise time than pulses generated without resonance. As a result, the faster rise time of the current reduces the variation in the time from when resonance begins in the light-emitting device 10 to when the light-emitting element 11 begins to emit light.

[0038] In the resonant circuit RC, if the impedance becomes low at a frequency different from the resonant frequency, resonance may not occur. In this case, even if a current is generated in the light emitting device 10, the rise of this current is slow, and accordingly, the rise of the emitted light is also slow. Therefore, in this embodiment, the storage elements provided in the resonant circuit RC are limited. More specifically, the resonant circuit RC is not provided with any storage elements other than the capacitor layer 132. In this case, compared to a configuration in which the storage elements are provided in the resonant circuit RC without any restrictions, an increase in the capacitance and inductance in the resonant circuit RC is suppressed, and accordingly, a decrease in impedance at frequencies different from the resonant frequency is suppressed.

[0039] In this embodiment, the light emitting device 10 further includes a resistor 15 connected in a circuit between the power supply 14 and the resonant circuit RC to suppress charge transfer between the power supply 14 and the resonant circuit RC. When resonance occurs, if the resonant circuit RC is affected by a circuit outside the resonant circuit RC, for example, when charge is supplied from the power supply 14 to the capacitor layer 132, the resonance in the resonant circuit RC may be attenuated. Therefore, in this embodiment, by connecting a resistor 15 to the circuit between the power supply 14 and the resonant circuit RC, the resonant circuit RC is prevented from being affected by the power supply 14 when resonance occurs in the resonant circuit RC.

[0040] In this embodiment, the substrate 13 has a plurality of layers including the capacitor layer 132, and the light emitting element 11 is provided so as to overlap these layers. When the light-emitting element 11 is arranged so as not to overlap with the capacitor layer 132, for example, by being spaced apart from the substrate 13 in the front-to-back direction (see FIG. 3(a)) or the left-to-right direction, the electric path between the light-emitting element 11 and the capacitor layer 132 becomes longer than when the light-emitting element 11 overlaps with the capacitor layer 132. In other words, when the light-emitting element 11 is arranged so as not to overlap with the capacitor layer 132, the electric path in the resonant circuit RC becomes longer than when the light-emitting element 11 overlaps with the capacitor layer 132. Therefore, in this embodiment, the light-emitting element 11 is arranged so as to overlap with the capacitor layer 132. In particular, in this embodiment, the layers of the substrate 13 on which the light emitting element 11 overlaps include a cathode layer 1311 that is provided in the resonant circuit RC and through which the current supplied to the light emitting element 11 passes.

[0041] (Variation) Next, a modified example will be described. In the present embodiment, it has been described that the resistor 15 that suppresses charge transfer between the power supply 14 and the resonant circuit RC is provided in the light emitting device 10. Here, the suppression means that suppresses charge transfer between the power supply 14 and the resonant circuit RC is not limited to the resistor 15. FIG. 6 is a diagram showing an electronic circuit of a modified light emitting device 10. In FIG. In a modification, as shown in FIG. 6, a transistor 16 is connected in place of the resistor 15 in the circuit between the power supply 14 and the resonant circuit RC. The transistor 16, which is an example of a suppression means, is an electronic switch that switches between a state in which the circuit from the power supply 14 to the resonant circuit RC is conductive and a state in which it is not conductive, depending on the voltage applied to it.

[0042] When a voltage equal to or greater than a predetermined value is applied to the transistor 16, the transistor 16 is in an ON state. In this case, the circuit to which the transistor 16 is connected is connected, and the circuit from the power supply 14 to the resonant circuit RC is in a conductive state, so that an electric charge is supplied from the power supply 14 to the capacitor layer 132 of the substrate 13, thereby charging the capacitor layer 132. At this time, the electric charge is supplied more quickly than when the electric charge is supplied via a resistor 15 or the like having the resistance required to isolate the resonant circuit RC. Furthermore, when a voltage equal to or greater than a predetermined value is not applied to the transistor 16, the transistor 16 is in an OFF state. In this case, the circuit to which the transistor 16 is connected is cut off, and the circuit from the power supply 14 to the resonant circuit RC is not conducting. At this time, no charge moves between the power supply 14 and the resonant circuit RC. Furthermore, if charging of the capacitor layer 132 is completed at this time, a current is supplied from the capacitor layer 132 to the light-emitting element 11, causing the light-emitting element 11 to emit light.

[0043] As described above, in this embodiment, the transistor 16 interrupts conduction in the circuit between the power supply 14 and the resonant circuit RC, thereby making it easier for resonance to occur in the resonant circuit RC.

[0044] Next, a description will be given of parameters for the detection device 1 that are required to speed up the rise of light. Note that, in the following, it is assumed that the light emitting device 10 is used as a light source for dTOF. FIG. 7( a ) is a diagram showing parameters for the detection device 1 .

[0045] 7(a) indicates the type of LiDAR used in the detection device 1. The "batch irradiation type" indicated in the "type" indicates that a batch irradiation type LiDAR is used in the detection device 1. Furthermore, the "scanning type" indicated in the "type" indicates that a scanning type LiDAR is used in the detection device 1. Moreover, the "inductance" shown in FIG. 7(a) means the inductance in the resonant circuit RC. 7(a) means the distance to the object T that the detection device 1 is to detect. Moreover, the "peak current" shown in FIG. 7(a) means the maximum value of the current that occurs when the transistor 124 is turned on.

[0046] Also, the "pulse half width" shown in Figure 7(a) refers to the half width of the pulse generated by resonance in the resonant circuit RC. The "pulse half width" can also be understood as the time required for the current to rise after the pulse is generated. 7(a) refers to the accuracy with which the detection device 1 detects the distance to the target T. The "accuracy" can also be understood as an error in the distance to the target T detected by the detection device 1, which occurs due to the time it takes for the light to rise after the detection device 1 starts emitting light. 7(a) means the capacitance of the dielectric layer 1322 in the capacitor layer 132. In FIG. 7(a) means the voltage applied by the power supply 14.

[0047] The values ​​shown in Fig. 7(a) will be specifically explained. In the detection device 1 where the "detection distance" is between "5" and "20" and inclusive, the "inductance" is 0.4. In addition, in the detection device 1 where the "detection distance" is between "50" and "200" and inclusive, the "inductance" is 0.8. 7(a), the capacitance of the dielectric layer 1322 is 10 pF or more and 1000 pF or less. In other words, when the dielectric layer 1322 having a capacitance of 10 pF or more and 1000 pF or less is used, the rise of light becomes faster.

[0048] Fig. 7(b) is a diagram showing the relationship between the relative permittivity, length a, length b, and thickness d for the dielectric layer 1322 to have a capacitance of approximately 10 pF, and Fig. 7(c) is a diagram showing the relationship between the relative permittivity, length a, length b, and thickness d for the dielectric layer 1322 to have a capacitance of approximately 1000 pF.

[0049] The "capacitance" shown in FIGS. 7(b) and 7(c) refers to the capacitance of the dielectric layer 1322. 7(b) and 7(c) denotes the relative dielectric constant of the dielectric layer 1322. Moreover, "w1" shown in FIGS. 7(b) and 7(c) means the length a of the dielectric layer 1322 in the front-to-rear direction (see FIG. 3(a)). Moreover, "w2" shown in FIGS. 7(b) and 7(c) means the length b (see FIG. 3(a)) of the dielectric layer 1322 in the left-right direction. Furthermore, "d" shown in FIGS. 7(b) and 7(c) denotes the thickness d of the dielectric layer 1322 in the vertical direction (see FIG. 2).

[0050] 7(b) and 7(c), it has been described that "w1" is the length a of the dielectric layer 1322 in the front-to-rear direction and "w2" is the length b of the dielectric layer 1322 in the left-to-right direction, but this is not limiting. "w1" may be the length b of the dielectric layer 1322 in the left-to-right direction, and "w2" may be the length a of the dielectric layer 1322 in the front-to-rear direction.

[0051] The capacitances shown in FIGS. 7(b) and 7(c) are calculated from the following formula (2). TIFF0007739899000002.tif23163 In equation (2), C is the capacitance of the dielectric layer 1322. ε is the dielectric constant of a vacuum. In addition, Figures 7(b) and 7(c) show capacitances rounded to one decimal place.

[0052] The values ​​shown in Figures 7(b) and 7(c) will be specifically described. In both detection devices 1 shown in Figure 7(b), the capacitance of the dielectric layer 1322 is 10 pF or more. In other words, by satisfying the relationships shown in the figure among the relative permittivity, the length a in the front-to-back direction, the length b in the left-to-right direction, and the thickness d in the up-to-down direction of the dielectric layer 1322, the capacitance of the dielectric layer 1322 becomes 10 pF or more. 7(c), the capacitance of the dielectric layer 1322 was approximately 1000 pF. In other words, by setting the relationship between the relative permittivity, the length a in the front-to-back direction, the length b in the left-to-right direction, and the thickness d in the up-to-down direction of the dielectric layer 1322 as shown in the figure, the capacitance of the dielectric layer 1322 becomes approximately 1000 pF.

[0053] 7(b) shows that when “εr” is “20” and “d” is “0.02”, the area of ​​the dielectric layer 1322 is “1.15×10”, which is the smallest value among the values ​​shown in FIG. 7(b) and FIG. 7(c). -6 m 2 However, if the relative permittivity of the dielectric layer 1322 is made higher or the thickness d of the dielectric layer 1322 is made shorter, the area of ​​the dielectric layer 1322 may be increased to "10 -7 m 2 Even if the capacitance of the dielectric layer 1322 is 10 pF or more and 1000 pF or less, the capacitance of the dielectric layer 1322 is 10 pF or more and 1000 pF or less. That is, the area of ​​the dielectric layer 1322 required for the dielectric layer 1322 to satisfy the capacitance of 10 pF or more and 1000 pF is at least "10 -7 m 2 " or more is sufficient.

[0054] 7(c) shows that when “εr” is “100” and “d” is “0.05”, the area of ​​the dielectric layer 1322 is “5.7×10”, which is the maximum value among the values ​​shown in FIG. 7(b) and FIG. 7(c). -5 m 2 However, if the relative permittivity of the dielectric layer 1322 is made lower or the thickness d of the dielectric layer 1322 is made longer, the area of ​​the dielectric layer 1322 becomes "10 -3 m 2 Even if the capacitance of the dielectric layer 1322 is 10 pF or more and 1000 pF or less, the capacitance of the dielectric layer 1322 is 10 pF or more and 1000 pF or less. -3 m 2 " or less is sufficient.

[0055] 7(c) shows that when "εr" is "10," "w1" is "4," and "w2" is "3," "d" is "0.001 mm," the smallest value among the values ​​shown in FIGS. 7(b) and 7(c). However, if the relative permittivity of the dielectric layer 1322 is lowered or the area of ​​the dielectric layer 1322 is narrowed, the capacitance of the dielectric layer 1322 will be 10 pF or more and 1000 pF or less, even if "d" is 0.0005 mm. In other words, the thickness d of the dielectric layer 1322 required to satisfy the capacitance requirement of 10 pF or more and 1000 pF or less needs to be at least 0.0005 mm.

[0056] 7(c) also shows that the maximum value of "d" among the values ​​shown in FIGS. 7(b) and 7(c) is "0.05 mm." However, if the relative permittivity of the dielectric layer 1322 is increased or the area of ​​the dielectric layer 1322 is increased, the capacitance of the dielectric layer 1322 will be 10 pF or more and 1000 pF or less even if "d" is "0.1 mm." In other words, the thickness d of the dielectric layer 1322 required to satisfy the capacitance requirement of 10 pF or more and 1000 pF or less needs to be "0.1 mm" or less.

[0057] 7(c) shows that when "w1" is "3," "w2" is "2," and "d" is "0.05," "εr" becomes "1000," which is the maximum value among the values ​​shown in FIGS. 7(b) and 7(c). However, if the area of ​​the dielectric layer 1322 is narrower or the thickness of the dielectric layer 1322 is increased, the capacitance of the dielectric layer 1322 becomes 10 pF or more and 1000 pF or less, even if "εr" is "10000." In other words, the relative permittivity of the dielectric layer 1322 required to satisfy the capacitance requirement of 10 pF or more and 1000 pF or less is only required to be "10000."

[0058] As described above, in this embodiment, the dielectric layer 1322 has an area of ​​10 -7 m 2 Over 10 -3 m 2 and the thickness is 5×10 -7 m or more 10 -4 m or less, and the relative dielectric constant is 3 to 10 4 The distance to the object T that the detection device 1 detects is between 0.1 m and 500 m. In particular, in this embodiment, the dielectric layer 1322 has an area of ​​10 -6 m 2 Over 10 -4 m 2 The thickness is 10 -6 m or more 5×10 -5 m or less, and the relative dielectric constant is 3 to 10 3 The following is the result.

[0059] In this embodiment, the substrate 13 of the light emitting device 10 has a capacitance of 10 -11 F or above 10 -9 The capacitor layer 132 has a dielectric layer 1322 that is a dielectric and is equal to or less than F and is provided in the resonant circuit RC.

[0060] In the present embodiment, the light emitting device 10 is described as not being provided with any power storage element other than the capacitor layer 132, but the present invention is not limited to this. For example, not only the capacitor layer 132 but also a storage element having a thickness smaller than that of the capacitor layer 132 may be provided on the substrate 13. That is, the resonant circuit RC should not be provided with a storage element having a thickness larger than that of the capacitor layer 132 and storing electric charge. In other words, the resonant circuit RC should not be provided with a storage element having a dielectric having a thickness larger than that of the dielectric layer 1322.

[0061] Furthermore, for example, other storage elements may be provided in the resonant circuit RC in addition to the capacitor layer 132, as long as the capacitance of the resonant circuit RC is in the range of 10 pF to 1000 pF. In other words, the resonant circuit RC should not be provided with any storage elements that cause the capacitance of the resonant circuit RC to exceed 1000 pF.

[0062] Furthermore, a power storage element may be provided in a circuit other than the resonant circuit RC among the electronic circuits of the light emitting device 10. As an example, in the light emitting device 10, a power storage element having a thickness greater than that of the capacitor layer 132 or a power storage element having a capacitance exceeding 1000 pF may be connected to the electric path between the power source 14 and the resonant circuit RC. Furthermore, the entire resonant circuit RC may be provided on the substrate 13. That is, it is sufficient that at least a part of the resonant circuit RC is provided on the substrate 13.

[0063] Furthermore, in the present embodiment, an example has been described in which the detection device 1 is provided on the moving body 2, but the detection device 1 may also be provided on a part that does not change position. When the detection device 1 is provided on a part that does not change position, the detection device 1 measures the distance to the object T, thereby making it possible to grasp the positional relationship between the detection device 1 and the object T in the space in which the object T exists.

[0064] Furthermore, in this embodiment, an example in which the light emitting device 10 is applied to the detection device 1 has been described, but the application of the light emitting device 10 is not limited to the detection device 1. For example, the light emitting device 10 may be applied to a device that transmits light by combining the light emitting device 10, an optical transmission path, and a light receiving unit 20. The light emitting device 10 may also be applied to a device that detects the internal structure of an object T, such as a living body, by irradiating the inside of the object T with light from the light emitting device 10.

[0065] Furthermore, in the present embodiment, a VCSEL is used as the light emitting device 10, but the light emitting device 10 may be an LED (Light Emitting Diode). In addition, in this embodiment, the light emitting element 11 emits light upward (see FIG. 2), but this is not limiting. The light emitting element 11 may emit light downward, i.e., toward the back surface of the substrate 13.

[0066] Furthermore, a transfer element specialized for controlling the timing at which the light emitting element 11 emits light in response to the supply of current in the resonant circuit RC may be provided on the substrate 13. As a specific example of the transfer element, the light emitting element 11 may be configured as a light emitting thyristor connected in series with a VCSEL, and the transfer thyristor that supplies a signal to the light emitting thyristor to emit light may be configured monolithically.

[0067] Although the embodiments of the present invention have been described above, the technical scope of the present invention is not limited to the scope described in the above embodiments. It is clear from the claims that various modifications and improvements to the above embodiments are also included in the technical scope of the present invention. [Explanation of symbols]

[0068] 1...detection device, 10...light-emitting device, 11...light-emitting element, 13...substrate, 20...light-receiving section, 30...detection section, 131...upper circuit layer, 132...capacitor layer, 1321...ground layer, 1322...dielectric layer, 1323...anode layer

Claims

1. a substrate provided with a resonant circuit that generates resonance; a light-emitting element disposed in the resonant circuit, the light-emitting element emitting light when a current generated by the resonant circuit being turned on and causing resonance is supplied via a storage layer including a storage element for storing electric charges; a suppression means connected to a circuit between a power source that supplies electric charge to the storage layer and the resonant circuit, and that suppresses charge transfer between the power source and the resonant circuit; Equipped with the resonant circuit does not include any other storage element that stores electric charge and that has a thickness in the vertical direction greater than that of the storage element that constitutes the storage layer, A light-emitting device characterized in that the suppression means is a resistor, and the resistor has a predetermined electrical resistance that suppresses the attenuation of resonance due to the influence of the power supply when resonance occurs in the resonant circuit.

2. A substrate on which a resonant circuit that generates resonance is provided; a light-emitting element that emits light when a current generated by the resonance circuit being turned on is supplied via a storage layer including a storage element that stores electric charge; a suppression means connected to a circuit between a power source that supplies electric charge to the storage layer and the resonant circuit, and that suppresses charge transfer between the power source and the resonant circuit; Equipped with the resonant circuit does not include any other storage element that stores electric charge and that has a thickness in the vertical direction greater than that of the storage element that constitutes the storage layer, A light-emitting device characterized in that the suppression means is a transistor, and a voltage of a magnitude that would cause the circuit between the power supply and the resonant circuit to be conductive is not applied to the transistor when resonance occurs in the resonant circuit.

3. The light emitting device according to claim 1 or 2; a light receiving means for receiving light emitted from the light emitting device and projected onto an object; a detecting means for detecting a distance to the object based on the light received by the light receiving means; Equipped with the storage layer has a dielectric layer that is a dielectric material, The dielectric layer has an area of ​​10 －７ m ２ 10 above －３ m ２ The thickness is 5×10 －７ m or more 10 －４ m or less, and the relative dielectric constant is 3 to 10 ４ is as follows: A detection device characterized in that the distance to the target object is within a range of 0.1 m to 500 m.

4. The dielectric layer has an area of ​​10 －６ m ２ 10 above －４ m ２ The thickness is 10 －６ m or more 5×10 －５ m or less, and the relative dielectric constant is 3 to 10 ３ 4. The detection device according to claim 3, wherein:

5. the substrate has a plurality of layers including the storage layer; 3. The light emitting device according to claim 1, wherein the light emitting element is provided so as to overlap the plurality of layers.

6. 6. The light emitting device according to claim 5, wherein the plurality of layers includes a layer provided in the resonant circuit and through which a current supplied to the light emitting element passes.

7. a substrate provided with a resonant circuit that generates resonance; a light-emitting element disposed in the resonant circuit, the light-emitting element emitting light when a current generated by the resonant circuit being turned on and causing resonance is supplied via a storage layer including a storage element for storing electric charges; a suppression means connected to a circuit between a power source that supplies electric charge to the storage layer and the resonant circuit, and that suppresses charge transfer between the power source and the resonant circuit; Equipped with The substrate has a capacitance of 10 －１１ F or above 10 －９ a storage layer provided in the resonant circuit, the storage layer having a dielectric layer of F or less and a dielectric; A light-emitting device characterized in that the suppression means is a resistor, and the resistor has a predetermined electrical resistance that suppresses the attenuation of resonance due to the influence of the power supply when resonance occurs in the resonant circuit.

8. A substrate on which a resonant circuit generating resonance is provided; a light-emitting element that emits light when a current generated by the resonance circuit being turned on is supplied via a storage layer including a storage element that stores electric charge; a suppression means connected to a circuit between a power source that supplies electric charge to the storage layer and the resonant circuit, and that suppresses charge transfer between the power source and the resonant circuit; Equipped with the substrate has a dielectric layer having a capacitance of 10 −11 F or more and 10 −9 F or less, and is a dielectric material, and the substrate has a storage layer provided in the resonant circuit; A light-emitting device characterized in that the suppression means is a transistor, and a voltage of a magnitude that would cause the circuit between the power supply and the resonant circuit to be conductive is not applied to the transistor when resonance occurs in the resonant circuit.

Images