Light source device
View Patent ↗A light source device includes a mounted substrate which is a multi-layered substrate, a semiconductor light-emitting device which emits a laser beam, a wavelength-converting member which radiates fluorescence by being irradiated with the laser beam emitted from the semiconductor light-emitting device as an excitation light, a state detection circuit, an electric field effect type transistor which adjusts an electric current amount applied to the semiconductor light-emitting device upon receipt of an output from the state detection circuit, and an external connecting member, and the semiconductor light-emitting device, the state detection circuit, the transistor, and the external connecting member are mounted on the single mounted substrate.
1. A light source device used for exterior illumination of a vehicle, comprising:
a single mounted substrate;
a semiconductor light-emitting device which emits a laser beam;
an external connecting member connected to the semiconductor light-emitting device and to which a driving current of the semiconductor light-emitting device is supplied from outside the light source device;
a wavelength-converting member which radiates wavelength-converted fluorescence when irradiated with the laser beam as an excitation light;
an operation state detection circuit which includes one or more light-receiving elements, detects an operation state of the light source device in accordance with light information detected by the one or more light-receiving elements, and outputs an operation state signal;
a microcontroller which controls the operation of the semiconductor light-emitting device in accordance with the operation state signal; and
a non-volatile memory which is disposed inside the microcontroller or on the single mounted substrate, wherein
the semiconductor light-emitting device, the external connecting member, the microcontroller, and the operation state detection circuit are mounted on the single mounted substrate,
the one or more light-receiving elements receive a scattered light generated by scattering the laser beam on the wavelength-converting member or the wavelength-converted fluorescence,
an initial light amount value according to a light amount of at least a light amount of the scattered light or a light amount of the wavelength-converted fluorescence when the semiconductor light-emitting device is operated under an initial state measurement condition is stored in the non-volatile memory, and
operation control of the semiconductor light-emitting device is executed by using the initial light amount value.
2. The light source device according to claim 1 , wherein
a temporal change coefficient related to aging over time of the semiconductor light-emitting device determined in advance and accumulated operation time of the semiconductor light-emitting device measured by using the microcontroller and the non-volatile memory are stored in the non-volatile memory, and
operation control of the semiconductor light-emitting device is executed by using the initial light amount value, the temporal change coefficient, and the accumulated operation time.
3. The light source device according to claim 1 , wherein
the operation state detection circuit includes a temperature detection element and outputs the operation state signal in accordance with temperature information detected by the temperature detection element.
4. The light source device according to claim 3 , wherein
an initial temperature value according to a temperature when the semiconductor light-emitting device is operated under an initial state measurement condition is stored in the non-volatile memory, and
operation control of the semiconductor light-emitting device is executed by using the initial temperature value and the temperature information.
5. The light source device according to claim 3 , wherein
driving current information according to the temperature information is stored in the non-volatile memory, and
operation control of the semiconductor light-emitting device is executed by using the driving current information.
6. The light source device according to claim 1 , further comprising:
a transistor which controls an operation of the semiconductor light-emitting device, wherein
the transistor is mounted on the single mounted substrate.
7. The light source device according to claim 6 , wherein
the transistor is connected in series to the semiconductor light-emitting device.
8. The light source device according to claim 1 , wherein
the semiconductor light-emitting device has an anode terminal and a cathode terminal, and
the operation state detection circuit detects a voltage of the anode terminal and outputs the operation state signal in accordance with detected voltage information.
9. The light source device according to claim 1 , further comprising:
a transistor which controls an operation of the semiconductor light-emitting device, wherein
the microcontroller controls the transistor in accordance with the operation state signal, independently of control outside the light source device.
10. The light source device according to claim 1 , wherein
when the operation state signal indicates operation abnormality of the light source device, the semiconductor light-emitting device is pulse-driven and has operation controlled by referring to an output signal of the one or more light-receiving elements during a pulse-off period of the pulse driving.
11. The light source device according to claim 1 , further comprising:
a gain switching circuit which controls an amplitude of an output signal of the one or more light-receiving elements between the one or more light-receiving elements and the microcontroller.
12. The light source device according to claim 1 , further comprising:
an optical filter in an optical waveguide between the wavelength-converting member and the one or more light-receiving elements.
13. The light source device according to claim 1 , further comprising:
a base on which the wavelength-converting member is installed; and
a base cover having a plate shape and an arithmetic mean roughness of a surface at 0.5 μm or more in a periphery of the wavelength-converting member.
14. The light source device according to claim 1 , further comprising:
a light transmitting member in a light emission path to an outside, wherein
the light transmitting member is a light collecting lens.
15. The light source device according to claim 1 , wherein
the single mounted substrate is a multi-layered wiring board having three layers or more,
the semiconductor light-emitting device has an anode terminal and a cathode terminal, and
inner wiring of the single mounted substrate is used for wiring connecting the anode terminal or the cathode terminal and the external connecting member.
16. The light source device according to claim 3 , wherein
the temperature detection element is disposed between the semiconductor light-emitting device and the microcontroller in plan view.