Compact flat panel color calibration system

• US 8,179,405 B2
• Filed: 07/29/2008
• Issued: 05/15/2012
• Est. Priority Date: 12/08/2000
• Status: Expired due to Fees

• Current Assignee: RPX Corporation
• Original Assignee: Graphics Properties Holdings, Inc.
• Inventors: Evanicky, Daniel, Granger, Ed, Ingulsrud, Joel, Ming, Alice T.
• Primary Examiner(s): Shankar, Vijay
• Application Number:
  US12/181,773
• Publication Number:
  US 20090051711A1
• Time in Patent Office: 1,386 Days
• Field of Search: 345 76- 89, 345204-215, 345690-699
• US Class Current: 345/690
• CPC Class Codes: G09G 2320/0606 Manual adjustment
• CPC Class Codes: G09G 2320/0626 for control of overall brightness
• CPC Class Codes: G09G 2320/0666 for control of colour parameters, e.g. colour temperature
• CPC Class Codes: G09G 2320/0673 for control of gamma adjustment, e.g. selecting another gamma curve
• CPC Class Codes: G09G 2320/0693 Calibration of display systems
• CPC Class Codes: G09G 2340/0407 Resolution change, inclusive of the use of different resolutions for different screen areas
• CPC Class Codes: G09G 2360/145 the light originating from the display screen
• CPC Class Codes: G09G 3/006 Electronic inspection or testing of displays and display drivers, e.g. of LED or LCD displays testing individual LED's G01R31/2635; testing lamps G01R31/44; testing of optical features of LCD displays G02F1/1309
• CPC Class Codes: G09G 3/20 for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix no fixed position being assigned to or needed to be assigned to the individual characters or partial characters
• CPC Class Codes: G09G 3/3648 using an active matrix G09G3/367 - G09G3/3696 take precedence
• CPC Class Codes: G09G 5/005 Adapting incoming signals to the display format of the display terminal
• CPC Class Codes: G09G 5/006 Details of the interface to the display terminal specific for a display terminal using a CRT G09G1/167; using a flat panel G09G3/2096; circuits for interfacing with colour displays G09G5/04
• CPC Class Codes: H04N 17/02 for colour television signals
• CPC Class Codes: H04N 17/04 for receivers
• CPC Class Codes: H04N 9/30 using solid-state colour display devices

Abstract

A compact flat panel color calibration system includes a lens prism optic able to pass a narrow, perpendicular, and uniform cone angle of incoming light to a spectrally non-selective photodetector. The calibration system also includes a microprocessor operable to determine the luminance of the display based upon the information gathered by the photodetector. A software module included in the calibration system is then operable to process the luminance information in order to adjust the flat panel display.

Claims

1. A method of calibrating a display, comprising:

setting an illumination level of a first illumination lamp to its minimum illumination level and recording a first minimum input signal from a power source to the first illumination lamp;

setting an illumination level of a second illumination lamp to its minimum illumination level and recording a second minimum input signal from the power source to the second illumination lamp;

increasing the illumination level of the first illumination lamp to its maximum illumination level and recording a first maximum input signal from the power source to the first illumination lamp;

increasing the illumination level of the second illumination lamp to its maximum illumination level and recording a second maximum input signal from the power source to the second illumination lamp;

determining the difference between the first and second minimum input signals;

determining the difference between the first and second maximum input signals; and

using the differences in the minimum and maximum input signals to map the illumination levels of the first and second illumination lamps as functions of the input signals.

2. The method of claim 1, wherein increasing the illumination level of each of the first and second illumination lamps to its maximum illumination level is performed in four steps.

3. The method of claim 1, further comprising:

identifying starting tristimulus values for the first and second illumination lamps;

determining initial and differential states of the first and second illumination lamps from the tristimulus values and the mapping of the respective illumination levels.

4. The method of claim 3, further comprising:

setting luminance and color temperature of the display.

5. A method of calibrating a display, comprising:

setting an illumination level of a first illumination lamp to a first illumination level and recording a first input signal from a power source to the first illumination lamp;

setting an illumination level of a second illumination lamp to a first illumination level and recording a first input signal from the power source to the second illumination lamp;

decrementing the illumination level of the first illumination lamp to a second illumination level and recording a second input signal from the power source to the first illumination lamp;

decrementing the illumination level of the second illumination lamp to a second illumination level and recording a second input signal from the power source to the second illumination lamp;

determining a difference between the first input signals of the first and second illumination lamps; and

determining a difference between the second input signals of the first and second illumination lamps.

6. The method of claim 5, further comprising:

returning the first illumination lamp to the first illumination level prior to decrementing the illumination level of the second illumination lamp to the second illumination level.

7. The method of claim 5, further comprising:

setting the luminance and color temperature of the display in response to the differences.

8. The method of claim 7, further comprising:

repeating all setting, decrementing and determining steps until the differences reach a zero state.

9. The method of claim 5, wherein the first illumination levels of the first and second illumination lamps are at a center position of their respective ranges.

10. The method of claim 5, further comprising:

using the differences in the first and second input signals to map the respective illumination levels of the first and second illumination lamps as functions of the respective input signals.

11. The method of claim 10, further comprising:

identifying starting tristimulus values for the first and second illumination lamps;

determining initial and differential states of the first and second illumination lamps from the tristimulus values and the mapping of the respective illumination levels.

12. A method of calibrating a display, comprising:

instructing a sensor system to measure a luminance level of a splash screen generated on a display;

receiving the luminance level of the splash screen; and

providing control information to a backlight driver to set the luminance level on a backlight of the display, the method further comprising;

instructing a sensor system to measure a luminance level of a plurality of splash screens generated on a display;

receiving the luminance level of each splash screen; and

providing control information to a backlight driver to set the luminance level on a backlight of the display in response to the luminance levels of the plurality of splash screens.

13. The method of claim 12 wherein the splash screen is a gray scale splash screen.

14. The method of claim 12 wherein the display includes a liquid crystal module.

15. The method of claim 12 wherein the control information is provided through to the backlight driver through a backlight application programming interface.

16. The method of claim 12 further comprising:

providing control information to the backlight driver to set a white balance level on the backlight of the display.

17. The method of claim 12 further comprising:

calculating a gamma value to load into a lookup table for the display.

18. The method of claim 12, further comprising:

setting the appropriate white balance and luminance levels of the display in accordance with the control information;

calculating proper gamma values to load into lookup tables of the display.

19. The method of claim 18, further comprising:

communicate luminance, white balance, and gamma information electronically to other monitors for calibration thereof in a Master/Slave relationship.