Color calibration system

• US 8,405,674 B2
• Filed: 12/30/2009
• Issued: 03/26/2013
• Est. Priority Date: 01/23/2009
• Status: Active Grant

• Current Assignee: Rakuten Group, Inc.
• Original Assignee: Mitsubishi Electric Corporation
• Inventors: Sakai, Hidenori, Arakawa, Yasuhiro, Ueno, Hiroshi, Tanizoe, Hideki
• Primary Examiner(s): Ma, Tize
• Assistant Examiner(s): He, Yingchun
• Application Number:
  US12/650,294
• Publication Number:
  US 20100188418A1
• Time in Patent Office: 1,182 Days
• Field of Search: None
• US Class Current: 345/593
• CPC Class Codes: G01J 1/4204 with determination of ambient light solar light G01J2001/4266
• CPC Class Codes: G01J 3/50 using electric radiation detectors
• CPC Class Codes: G01J 3/506 measuring the colour produced by screens, monitors, displays or CRTs
• CPC Class Codes: G09G 2320/0666 for control of colour parameters, e.g. colour temperature
• CPC Class Codes: G09G 2360/144 the light being ambient light
• CPC Class Codes: G09G 5/02 characterised by the way in which colour is displayed details of colour display specific for CRTs G09G1/28; specific for flat matrix panels other than liquid crystal displays G09G3/2003; specific for liquid crystal displays G09G3/3607

Abstract

A color calibration system in accordance with a preferred embodiment of the present invention comprises a display device provided with a color sensor for detecting a color temperature and illuminance of ambient light, a microcomputer, and a colorimeter for performing colorimetry on a display screen of the display device from the outside. The microcomputer calculates a target value by using a preset calculation equation and a detection result on the ambient light detected by the color sensor. Then, the microcomputer automatically performs color calibration of the display device so that a colorimetry result obtained by the colorimeter may agree with the target value.

Claims

1. A color calibration system, comprising:

a display device provided with a color sensor for detecting a color temperature and illuminance of ambient light;

a microcomputer;

a colorimeter for performing colorimetry on a display screen of said display device from outside the display device;

a control unit;

a first temperature sensor provided at a first location of said display device; and

a second temperature sensor provided at a second location where the temperature is higher than that of said first location during operation,

wherein said microcomputer calculates a target value by using a preset calculation equation and a detection result on said ambient light detected by said color sensor, and

said control unit determines whether or not to automatically perform color calibration of said display device so that a colorimetry result obtained by said colorimeter agrees with said target value on the basis of a time variation of a differential value between a detection result obtained by said first sensor and a detection result obtained by said second temperature sensor and a preset threshold value.

2. The color calibration system according to claim 1, wherein

said color sensor is an RGB color sensor for outputting a measurement result as an RGB value,

said calculation equation is expressed as

3. The color calibration system according to claim 2, wherein

calculation of said matrix correction, factor matrix is performed before performing said color calibration by using an RGB measurement result obtained by said color sensor on a predetermined color temperature sample and an XYZ measurement result obtained by a reference colorimeter on said predetermined color temperature sample, and

said matrix correction factor matrix after said calculation is set in said microcomputer.

4. The color calibration system according to claim 1, wherein said display device comprises

a ventilation unit through which air is taken from the outside to the inside of the display device;

and

a liquid crystal unit for displaying an image,

said first location is near said ventilation unit, and

said second location is at a center portion of said liquid crystal unit in the inside of said display device.

5. The color calibration system according to claim 1, wherein said control unit determines not to perform said color calibration if said time variation is larger than said threshold value.

6. The color calibration system according to claim 5, further comprising a notification means for providing notification of the result of the determination when said control unit determines not to perform said color calibration.

7. The color calibration system according to claim 6, wherein after said control unit determines not to perform said color calibration, when said control unit detects that said time variation is not larger than said threshold value, said microcomputer performs said color calibration after said detection.

8. The color calibration system according to claim 1, wherein said control unit determines to perform said color calibration when said time variation is not larger than said threshold value.

9. A color calibration system, comprising:

a display device;

a microcomputer;

a colorimeter for performing colorimetry on a display screen of said display device from outside the display device;

a control unit;

a first temperature sensor provided at a first location of said display device; and

a second temperature sensor provided at a second location where the temperature is higher than that of said first location during operation,

wherein said microcomputer comprises a storage unit for storing target values corresponding to a combination of the type of lighting and the type of illuminance therein,

displays said type of lighting and said type of illuminance as a selection menu in a selectable manner on a predetermined display unit,

reads a predetermined said target value out from said storage unit in accordance with a combination of said type of lighting and said type of illuminance which is selected from said selection menu, and

said control unit determines whether or not to automatically perform color calibration so that said predetermined target value which is read out agrees with a colorimetry result obtained by said colorimeter on the basis of a time variation of a differential value between a detection result obtained by said first sensor and a detection result obtained by said second temperature sensor and a preset threshold value.

10. The color calibration system according to claim 9, wherein said display device comprises

a ventilation unit through which air is taken from the outside to the inside of the display device;

and

a liquid crystal unit for displaying an image,

said first location is near said ventilation unit, and

said second location is at a center portion of said liquid crystal unit in the inside of said display device.

11. The color calibration system according to claim 9, wherein said control unit determines not to perform said color calibration if said time variation is larger than said threshold value.

12. The color calibration system according to claim 11, further comprising a notification means for providing notification of the result of the determination when said control unit determines not to perform said color calibration.

13. The color calibration system according to claim 12 wherein after said control unit determines not to perform said color calibration, when said control unit detects that said time variation is not larger than said threshold value, said microcomputer performs said color calibration after said detection.

14. The color calibration system according to claim 9, wherein said control unit determines to perform said color calibration when said time variation is not larger than said threshold value.

15. A color calibration system, comprising:

a display device provided with a color sensor for detecting a color temperature and illuminance;

a microcomputer;

a prism or a reflecting mirror attachable to and detachable from said display device; and

a control unit;

a first temperature sensor provided at a first location of said display device; and

a second temperature sensor provided at a second location where the temperature is higher than that of said first location during operation,

wherein said microcomputer calculates a target value by using a detection result on ambient light detected by said color sensor in a state where said prism or said reflecting mirror is not attached and a first calculation equation which is preset,

said color sensor performs colorimetry on a display screen of said display device, which is inputted through said prism or said reflecting mirror in a state where said prism or said reflecting mirror is attached, and

said control unit determines whether or not to automatically perform color calibration by using the result of said colorimetry obtained by said color sensor and said target value on the basis of a time variation of a differential value between a detection result obtained by said first sensor and a detection result obtained by said second temperature sensor and a preset threshold value.

16. The color calibration system according to claim 15, wherein

said color sensor is an RGB color sensor for outputting a measurement result as an RGB value,

said microcomputer has a second calculation equation for converting an RGB value which is a result of colorimetry obtained by said color sensor into an XYZ tristimulus value,

converts said result of colorimetry obtained by said color sensor into said XYZ tristimulus value by using said second calculation equation, and

automatically performs color calibration so that said XYZ tristimulus value after conversion agrees with said target value,

said first calculation equation is expressed as

17. The color calibration system according to claim 16, wherein

calculation of said first matrix correction factor matrix is performed by using an RGB measurement result obtained by said color sensor on a color temperature sample and

an XYZ measurement result obtained by a reference colorimeter on said color temperature sample before performing said color calibration,

calculation of said second matrix correction factor matrix is performed by using an RGB measurement result obtained by said color sensor on light of a color patch displayed on said display device, which is obtained through said prism or said reflecting mirror, and an XYZ measurement result obtained by a reference colorimeter of said color patch displayed on said display device before performing said color calibration, and

said first matrix correction factor matrix after said calculation and said second matrix correction factor matrix after said calculation are set in said microcomputer.

18. The color calibration system according to claim 15, wherein said display device comprises

a ventilation unit through which air is taken from the outside to the inside of the display device;

and

a liquid crystal unit for displaying an image,

said first location is near said ventilation unit, and

said second location is at a center portion of said liquid crystal unit in the inside of said display device.

19. The color calibration system according to claim 15, wherein said control unit determines not to perform said color calibration if said time variation is larger than said threshold value.

20. The color calibration system according to claim 19, further comprising a notification means for providing notification of the result of the determination when said control unit determines not to perform said color calibration.

21. The color calibration system according to claim 20, wherein after said control unit determines not to perform said color calibration, when said control unit detects that said time variation is not larger than said threshold value, said microcomputer performs said color calibration after said detection.

22. The color calibration system according to claim 15, wherein said control unit determines to perform said color calibration when said time variation is not larger than said threshold value.