Light-emitting device

Abstract

The present invention provides a light-emitting device that can switch between emitting light and generating electricity. [Solution] The light-emitting device comprises a light-emitting element that can switch between emitting light when power is supplied and generating electricity by absorbing light, a switching unit that switches between a light-emitting mode in which the light-emitting element emits light and a power-generating mode in which the light-emitting element generates electricity, and a battery that stores the power generated by the light-emitting element.

Description

Technical Field

[0001] The present disclosure relates to a light-emitting device.

Background Art

[0002] Various light-emitting devices that emit light when energized have been proposed. For example, Patent Document 1 discloses a light-emitting device used for a headlight, a turn lamp, or a rear lamp mounted on a vehicle.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] The light-emitting device disclosed in Patent Document 1 occupies a certain area of the vehicle even though it does not operate when there is no need to emit light, such as during the day. This problem is not limited to the light-emitting device mounted on a vehicle but may be common to any light-emitting device such as a streetlight or a signal. There is a need for a light-emitting device that can be effectively utilized even when there is no need to emit light.

Means for Solving the Problems

[0005] The present disclosure can be realized in the following forms.

[0006] (1) According to one aspect of the present disclosure, a light-emitting device is provided. The light-emitting device includes a light-emitting element capable of switching between emitting light when supplied with power and generating electricity by absorbing light, a light-emitting mode for causing the light-emitting element to emit light, a power generation mode for causing the light-emitting element to generate electricity, a switching unit for switching between the light-emitting mode and the power generation mode, and a battery for storing the power generated by the light-emitting element. This type of light-emitting device includes a light-emitting element capable of switching between light emission and power generation, a switching unit for switching between light emission mode and power generation mode, and a battery for storing the power generated by the light-emitting element. Therefore, the light-emitting device can perform both light emission and power generation. This allows the light-emitting device to be effectively utilized by using it for power generation even when there is no need for it to emit light. (2) In the above-described form of light-emitting device, the light-emitting element may emit light using the power stored in the battery. In this type of light-emitting device, the light-emitting element emits light using power stored in a battery, and therefore can emit light using power generated by the element itself. As a result, the light-emitting element can emit light even when there is no external power supply. Furthermore, compared to a configuration in which a separate battery is provided for supplying power for illumination and a separate battery for storing the generated power, the light-emitting device can be made more compact. (3) In the above-described form of light-emitting device, an MPPT circuit may be further provided between the battery and the light-emitting element. This type of light-emitting device also includes an MPPT (Maximum Power Point Tracking) circuit, allowing the light-emitting element to generate power with higher efficiency. (4) In the above-described form of light-emitting device, the light-emitting element may be a multi-junction compound semiconductor. In this type of light-emitting device, since the light-emitting element is a multi-junction semiconductor, it can utilize a wider range of light frequencies for power generation compared to the case where the light-emitting element is a single-junction semiconductor. This improves the power generation efficiency of the light-emitting device.

[0007] This disclosure can be implemented in various forms. For example, it can be implemented in the form of a vehicle equipped with a light-emitting device. [Brief explanation of the drawing]

[0008] [Figure 1] This is a block diagram showing a schematic configuration of a light-emitting device in one embodiment of the present disclosure. [Figure 2] This block diagram shows the schematic configuration of the light-emitting device according to the second embodiment. [Modes for carrying out the invention]

[0009] A. First Embodiment: Figure 1 is a block diagram showing the schematic configuration of a light-emitting device 1 in one embodiment of the present disclosure. The light-emitting device 1 in this embodiment is mounted on a vehicle and emits light and generates electricity. As shown in Figure 1, the light-emitting device 1 comprises a light-emitting element 100, a light-emitting circuit C1, a power generation circuit C2, a switching unit SW1, and a control device CT.

[0010] <Configuration of the light-emitting element 100> The light-emitting element 100 converts between electrical energy and light energy. That is, the light-emitting element 100 can switch between emitting light when power is supplied and generating electricity by absorbing light. The light-emitting element 100 is made of, for example, a compound semiconductor or a perovskite material. The compound semiconductor is, for example, a III-V compound. The light-emitting element 100 in this embodiment is a multi-junction compound semiconductor. The multi-junction compound semiconductor includes a plurality of compound semiconductors having different band gaps. The light-emitting element 100 in this embodiment is used in the headlights, turn signals, or taillights of a vehicle.

[0011] <Configuration of the light-emitting circuit C1> The light-emitting circuit C1 is used to supply power to the light-emitting element 100 and to make the light-emitting element 100 emit light. The light-emitting circuit C1 comprises a light-emitting battery 200 and a conductor W1. The light-emitting battery 200 stores power to supply to the light-emitting element 100. The conductor W1 connects the light-emitting element 100 and the light-emitting battery 200 by switching the switching unit SW1, which will be described later.

[0012] <Configuration of power generation circuit C2> The power generation circuit C2 is used to store the power generated by the light-emitting element 100. The power generation circuit C2 comprises a power generation battery 300, an MPPT (Maximum Power Point Tracking) circuit 400, and a conductor W2. The power generation battery 300 stores the power generated by the light-emitting element 100. The MPPT circuit 400 controls the power generation voltage of the light-emitting element 100 and causes the light-emitting element 100 to generate power at the optimal operating point where the output is maximum. A known control circuit can be used as the MPPT circuit 400. The conductor W2 connects the power generation battery 300 and the MPPT circuit 400. The conductor W2 also connects the light-emitting element 100 to the power generation battery 300 and the MPPT circuit 400 by switching the switching unit SW1, which will be described later.

[0013] <Configuration of the switching unit SW1> The switching unit SW1 is a switch connected to the light-emitting element 100. The switching unit SW1 switches between a light-emitting mode in which the light-emitting element 100 emits light and a power-generating mode in which the light-emitting element 100 generates electricity. The light-emitting mode is when the light-emitting element 100 is connected to the light-emitting circuit C1. The power-generating mode is when the light-emitting element 100 is connected to the power-generating circuit C2. Therefore, Figure 1 shows the state of the light-emitting mode. The switching unit SW1 is controlled by the control device CT, which will be described later.

[0014] <Configuration of the CT control unit> The control device CT controls the switching unit SW1. The control device CT is a computer comprising a CPU 10 and a memory 20. In this embodiment, the control device CT may be implemented as part of an ECU mounted on a vehicle. The CPU 10 makes the switching instruction unit 11 function by executing a control program stored in the memory 20.

[0015] The switching instruction unit 11 instructs the switching unit SW1 to switch the mode. The instruction to switch the mode is performed based on, for example, the presence or absence of a light emission instruction by the vehicle occupant. The light emission instruction is emitted, for example, when the occupant operates a vehicle switch when wanting to emit light from the light emitting element 100 as a vehicle headlamp. When the light emission instruction is emitted, the switching instruction unit 11 instructs the switching unit SW1 to switch to the light emission mode. When the light emission instruction is not emitted, the switching instruction unit 11 instructs the switching unit SW1 to switch to the power generation mode. Therefore, the light emitting element 100 functions in the light emission mode when it is necessary to emit light, for example, at night, and functions in the power generation mode when it is not necessary to emit light, for example, during the day.

[0016] According to the light emitting device 1 of the first embodiment described above, since it includes the light emitting element 100 capable of switching between light emission and power generation, the switching unit SW1 that switches between the light emission mode and the power generation mode, and the power generation battery 300 that stores the power generated by the light emitting element 100, the light emitting device 1 can be used for both light emission and power generation. Thereby, even when the light emitting device 1 does not need to emit light, the light emitting device 1 can be effectively utilized by using it for power generation.

[0017] Also, according to the light emitting device 1 of the first embodiment, since it includes the MPPT circuit 400, compared with a configuration in which the light emitting device 1 does not include the MPPT circuit 400, the light emitting element 100 can generate electricity with higher efficiency.

[0018] Also, according to the light emitting device 1 of the first embodiment, since the light emitting element 100 is a multi-junction compound semiconductor, compared with a configuration in which the light emitting element 100 is a single-junction compound semiconductor, light of a wider frequency range can be used for power generation. Thereby, the power generation efficiency of the light emitting device 1 can be improved.

[0019] In addition, since the light-emitting device 1 of the first embodiment is mounted on a vehicle, the light-emitting element 100 can be used as a headlight, a turn lamp, or a rear lamp of the vehicle. As a result, since the headlight, the turn lamp, and the rear lamp that occupy a certain area in the vehicle can be used for light emission and power generation, compared with a configuration in which both a light-emitting element that only emits light and a power generation element that only generates power are mounted on the vehicle, both light emission and power generation can be realized in a smaller space.

[0020] B. Second Embodiment: FIG. 2 is a block diagram showing a schematic configuration of the light-emitting device 1b of the second embodiment. The light-emitting device 1b of the second embodiment is different from the light-emitting device 1 of the first embodiment in that a single battery realizes a battery that supplies power for causing the light-emitting element 100 to emit light and a battery that stores the power generated by the light-emitting element 100. That is, the light-emitting device 1b of the second embodiment emits light using the power generated by the light-emitting device 1b itself. Regarding the configuration not described below, it is the same as that of the light-emitting device 1 of the first embodiment.

[0021] The light-emitting device 1b includes a light-emitting element 100, a light-emitting and power generation battery 500, a charge and discharge controller 600, and a switching unit SW2.

[0022] The light-emitting and power generation battery 500 stores the power generated by the light-emitting element 100. The stored power is used to cause the light-emitting element 100 to emit light.

[0023] The charge and discharge controller 600 is provided between the light-emitting element 100 and the light-emitting and power generation battery 500. The charge and discharge controller 600 adjusts the power generated by the light-emitting element 100. In addition, the charge and discharge controller 600 adjusts the power supplied to the light-emitting element 100. Specifically, the charge and discharge controller 600 suppresses overcharging and over-discharging of the light-emitting and power generation battery 500 by adjusting the voltage of the passing electricity. The charge and discharge controller 600 may include an MPPT circuit 400. The charge and discharge controller 600 has a terminal T1 used in the light-emitting mode and a terminal T2 used in the power generation mode.

[0024] The switching unit SW2 is a switch that switches the connection between the light-emitting element 100 and the charge / discharge controller 600. By connecting the switching unit SW2 to terminal T1, it switches to the light-emitting mode, and by connecting it to terminal T2, it switches to the power-generating mode. Therefore, Figure 2 shows the state in the light-emitting mode. The switching unit SW2 is controlled by the control device CT, similar to the light-emitting device 1 of the first embodiment.

[0025] According to the light-emitting device 1b of the second embodiment described above, the light-emitting element 100 emits light using the power stored in the light-emitting and power-generating battery 500, so the light-emitting element 100 can emit light even when there is no external power supply. Furthermore, compared to a configuration in which a battery for supplying power used for light emission and a battery for storing the generated power are provided separately, the light-emitting device 1b can be made more compact.

[0026] C. Other embodiments: (C1) In each of the above embodiments, the light-emitting element 100 may include a first light-emitting element and a second light-emitting element having a different band gap from the first light-emitting element. With such a configuration, the light-emitting element 100 can absorb a wider range of light and generate electricity compared to a configuration in which only a single type of light-emitting element is present.

[0027] Furthermore, the first light-emitting element may be configured to absorb the wavelength of light emitted by the second light-emitting element. With such a configuration, the first light-emitting element can generate electricity using the light emitted by the second light-emitting element. Furthermore, the second light-emitting element may be configured to absorb the wavelength of light emitted by the first light-emitting element. With such a configuration, the second light-emitting element can generate electricity using the light emitted by the first light-emitting element. Such a first light-emitting element may be composed of, for example, a plurality of compound semiconductors having different band gaps. The second light-emitting element may be composed of a different combination of compound semiconductors than the plurality of compound semiconductors that constitute the first light-emitting element.

[0028] (C2) In the first embodiment described above, the MPPT circuit 400 may be provided at any position between the light-emitting element 100 and the power generation battery 300.

[0029] (C3) In each of the above embodiments, the light-emitting devices 1,1b do not need to be equipped with an MPPT circuit 400. Even with such a configuration, the light-emitting devices 1,1b can switch between and perform both light emission and power generation.

[0030] (C4) In each of the above embodiments, the light-emitting element 100 was a multi-junction compound semiconductor, but the disclosure is not limited thereto. The light-emitting element 100 may be a single-junction compound semiconductor. Even with such a configuration, the light-emitting devices 1,1b can switch between and perform both light emission and power generation.

[0031] (C5) In each of the embodiments described above, the light-emitting devices 1,1b were mounted on a vehicle, but the disclosure is not limited thereto. The light-emitting devices 1,1b may be mounted on any structure that emits light. Such structures include, for example, traffic lights and streetlights. The light-emitting devices 1,1b may also be mounted on any mobile body. Such mobile bodies include, for example, ships, airplanes, spacecraft, and so-called flying cars. Furthermore, the mobile body is not necessarily limited to an object that realizes actual movement, but may also be an object that realizes virtual movement, such as a simulator.

[0032] This disclosure is not limited to the embodiments described above, and can be implemented in various configurations without departing from its spirit. For example, the technical features in the embodiments corresponding to the technical features in each form described in the summary of the invention can be replaced or combined as appropriate in order to solve some or all of the above-described problems, or to achieve some or all of the above-described effects. Furthermore, if a technical feature is not described as essential in this specification, it can be deleted as appropriate. [Explanation of symbols]

[0033] 1,1b...Light-emitting device, 100...Light-emitting element, 200...Light-emitting battery, 300...Power generator battery, 400...MPPT circuit, 500...Light-emitting / power generator battery, 600...Charge / discharge controller, C1...Light-emitting circuit, C2...Power generator circuit, CT...Control device, 10...CPU, 11...Switching indicator unit, 20...Memory, SW1,SW2...Switching unit, T1,T2...Terminals, W1,W2...Conducting wires

Claims

1. A light-emitting device, A light-emitting element that can switch between emitting light when powered and generating electricity by absorbing light, A switching unit that switches between a light-emitting mode in which the light-emitting element emits light and a power-generating mode in which the light-emitting element generates electricity, A battery that stores the power generated by the light-emitting element, A light-emitting device equipped with the following features.

2. A light-emitting device according to claim 1, The light-emitting element is a light-emitting device that emits light using the power stored in the battery.

3. A light-emitting device according to claim 2, further comprising an MPPT (Maximum Power Point Tracking) circuit between the battery and the light-emitting element.

4. A light-emitting device according to claim 3, wherein the light-emitting element is a multi-junction compound semiconductor.

5. A vehicle comprising a light-emitting device according to any one of claims 1 to 4.

Images