Light source device and method for modulating brightness of light emitted by same and liquid crystal display using same
First Claim
Patent Images
1. A light source device, comprising:
- a power supply;
a light source; and
a photodetector comprising a light sensor and a resistor connected in parallel;
wherein the power supply, the light source, and the resistor are connected in series, and when the intensity of ambient light increases, a resistance of the light sensor decreases so as to increase a light intensity of the light source, and when the intensity of ambient light decreases, the resistance of the light sensor increases so as to decrease the light intensity of the light source.
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Abstract
An exemplary light source device (10) includes a power supply (12), a light source (14), and a photodetector (16). The photodetector includes a light sensor (17) and a resistor (18) connected in parallel. The power supply, the light source, and the photodetector are connected in series. When the intensity of ambient light increases, a resistance of the light sensor decreases so as to increase a light intensity of the light source. When the intensity of ambient light decreases, the resistance of the light sensor increases so as to decrease the light intensity of the light source.
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Citations
17 Claims
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1. A light source device, comprising:
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a power supply; a light source; and a photodetector comprising a light sensor and a resistor connected in parallel; wherein the power supply, the light source, and the resistor are connected in series, and when the intensity of ambient light increases, a resistance of the light sensor decreases so as to increase a light intensity of the light source, and when the intensity of ambient light decreases, the resistance of the light sensor increases so as to decrease the light intensity of the light source. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11)
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12. A method for modulating a brightness of light emitted by a light source device, the method comprising:
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providing a power supply and a light source, the power supply providing a constant voltage to the light source; providing a photodetector, the photodetector comprising a doped polycrystalline silicon unit and a fixed resistance connected in parallel, the fixed resistance connected to the light source and the power supply in series, the doped polycrystalline silicon unit being sensitive to light and automatically changing its resistance in response to changes in ambient light; exposing the photodetector to ambient light; and the doped polycrystalline silicon unit automatically changing its resistance in response to a change in the ambient light, the photodetector thereby automatically modulating its own resistance, and thereby modulating a current passing through the light source such that a brightness of light emitted by the light source is modulated according to the ambient light. - View Dependent Claims (13, 14, 15, 16)
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17. A liquid crystal display, comprising:
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a liquid crystal panel; and a light source device positioned for illuminating the liquid crystal panel, the light source device comprising; a power supply; a light source; and a photodetector comprising a light sensor and a resistor connected in parallel; wherein the power supply, the light source, and the resistor are connected in series, and when the intensity of ambient light increases, a resistance of the light sensor decreases so as to increase a light intensity of the light source, and when the intensity of ambient light decreases, the resistance of the light sensor increases so as to decrease the light intensity of the light source.
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Specification