Light source unit and display device

• US 20040113044A1
• Filed: 09/30/2003
• Published: 06/17/2004
• Est. Priority Date: 12/13/2002
• Status: Active Grant

• Current Assignee: Mitsubishi Electric Corporation
• Original Assignee: Advanced Display Technologies
• Inventors: Ishiguchi, Kazuhiro
• Granted Patent: US 7,208,713 B2
• Time in Patent Office: Days
• US Class Current: 250/205
• CPC Class Codes: G02F 1/133628 with cooling means
• CPC Class Codes: H05B 45/22 using optical feedback
• CPC Class Codes: H05B 45/28 using temperature feedback

Abstract

A light source unit includes a light source having LED chips for emitting different colors of light and an optical sensor for detecting light from a light mixer. A light source control section controls by feedback control luminance of each of the LED chips according to values detected by the optical sensor. The light source unit also includes a temperature control section for controlling the temperature of the light source. The temperature control section is a feedback control system. Keeping the light source at a constant temperature allows suppressing spectrum changes of the LED chips with temperature, thereby suppressing changes in the luminance and chromaticity of the light source unit.

Claims

1. A light source unit comprising:

a light source comprising a plurality of light source elements for emitting different wavelengths of light;

a temperature controller for keeping the light source at constant temperature;

a light mixer for mixing light emitted by the plurality of light source elements;

a light detector for detecting light from the light mixer capable of detecting a plurality of different wavelengths of light; and

a light source controller for controlling luminance of each of the plurality of light source elements based on values detected by the light detector.

2. A light source unit according to claim 1, wherein the light detector detects a plurality of different wavelength ranges, and the light source controller controls luminance of each of the plurality of light source elements so that each detected value in the plurality of wavelength ranges approaches each given value.

3. A light source unit according to claim 1, further comprising a temperature detector for detecting temperature of the light source, wherein the temperature controller operates so that a value detected by the temperature detector approaches a given value.

4. A light source unit according to claim 1, wherein the temperature controller operates to keep the light source constant at constant temperature, and the light source controller controls luminance of each of the plurality of light source elements so that the light source unit has substantially constant chromaticity.

5. A light source unit according to claim 1, further comprising a temperature detector for detecting temperature of the light source, wherein the temperature controller changes a temperature value to be maintained in the light source based on a temperature value detected by the temperature detector, and the light source controller controls each of the plurality of light source elements to have luminance corresponding to the temperature value to be maintained.

6. A light source unit according to claim 1, wherein the light source comprises a plurality of light source elements emitting light with wavelengths corresponding to each of N (N is a natural number) number of colors, the light detector comprises N number of optical sensors corresponding to each of N number of colors, and the light source controller controls each of the plurality of light source elements so that each value detected by the N number of optical sensors approaches each given value.

7. A light source unit, comprising:

a light source comprising a plurality of light source elements for emitting different wavelengths of light;

a light mixer for mixing light emitted by the plurality of light source elements;

a light detector for detecting light from the light mixer capable of detecting a plurality of different wavelengths of light;

a temperature detector for detecting temperature of the light source; and

a light source controller for controlling luminance of each of the plurality of light source elements based on values detected by the light detector and the temperature detector.

8. A light source unit according to claim 7, wherein the light source controller controls luminance of each of the plurality of the light source elements based on a change in a value detected by the temperature detector so as to suppress a change in chromaticity of the light source unit

9. A light source unit according to claim 7, wherein the light source comprises a plurality of light source elements emitting light with wavelengths corresponding to each of N (N is a natural number) number of colors, the light detector comprises N number of optical sensors corresponding to each of N number of colors, and the light source controller controls each of the plurality of light source elements so that each value detected by the N number of optical sensors approaches each given value.

10. A light source unit according to claim 7, wherein the light source controller controls each of the plurality of light source elements to emit light with luminance corresponding to a temperature value detected by the temperature detector.

11. A display device comprising:

a light source unit; and

a display panel for displaying images by controlling light emitted by the light source unit;

the light source unit comprising;

a light source comprising a plurality of light source elements for emitting different wavelengths of light;

a temperature controller for keeping the light source at constant temperature;

a light mixer for mixing light emitted by the plurality of light source elements;

a light detector for detecting light from the light mixer capable of detecting a plurality of different wavelengths of light; and

a light source controller for controlling luminance of each of the plurality of light source elements based on values detected by the light detector.

12. A display device comprising:

a light source unit; and

a display panel for displaying images by controlling light emitted by the light source unit;

the light source unit comprising;

a light source comprising a plurality of light source elements for emitting different wavelengths of light;

a light mixer for mixing light emitted by the plurality of light source elements;

a light detector for detecting light from the light mixer capable of detecting a plurality of different wavelengths of light;

a temperature detector for detecting temperature of the light source; and

a light source controller for controlling luminance of each of the plurality of light source elements based on values detected by the light detector and the temperature detector.