System and method for constructing a backlighted display using dynamically optimized light source

• US 20070103934A1
• Filed: 11/10/2005
• Published: 05/10/2007
• Est. Priority Date: 11/10/2005
• Status: Abandoned Application

• Current Assignee: Avago Technologies ECBU IP Singapore Pte Limited (Broadcom, Inc.)
• Original Assignee: Avago Technologies General IP PTE Limited (Broadcom, Inc.)
• Inventors: Lee, Joon, Keh, Kean, Yap, Eit, Oon, Chin, Lim, Kevin
• Application Number:
  US11/271,186
• Publication Number:
  US 20070103934A1
• Time in Patent Office: Days
• US Class Current: 362/612
• CPC Class Codes: G02B 6/0068 Arrangements of plural sources, e.g. multi-colour light sources
• CPC Class Codes: G02B 6/0073 Light emitting diode [LED]
• CPC Class Codes: G09G 2320/0633 by amplitude modulation of the brightness of the illumination source
• CPC Class Codes: G09G 2320/0666 for control of colour parameters, e.g. colour temperature
• CPC Class Codes: G09G 2360/145 the light originating from the display screen
• CPC Class Codes: G09G 3/3413 Details of control of colour illumination sources

Abstract

A combination of light source types is used to form a dynamically adjusted backlighted display with the particular combination dependant upon the desired light output at a given point in time. In one embodiment, RGB diodes are used for low brightness situations and as the brightness requirement increases white light sources are added. In another embodiment, different light source types are used to produce the different color components and optical feedback is used to control the power levels of the various diode types.

Claims

1. A back-light display comprising:

a first light source having a first light emitting characteristic;

a second light source having a second light emitting characteristic, and

a control circuit for adjusting one of said light sources relative to the other of said light sources dependant upon the output brightness desired of said display at any point in time.

2. The display of claim 1 wherein said display is a LCD display.

3. The display of claim 1 wherein said first light source is a first LED type and said second light source is a second LED type.

4. The display of claim 3 wherein said first LED type are white diodes and said second LED type are RGB LEDs.

5. The display of claim 1 wherein said first light source are RGB LEDs and said second light source is selected from the list of:

CCFL, phosphor converted LEDs.

6. The display of claim 5 wherein said control circuit is further operable for enabling only said first LEDs when low brightness light outputs are required and for enabling both said first and said second LEDs when increased brightness output is required.

7. The display of claim 6 wherein said control circuit is further operable for gradually increasing the light output from said second LEDs as the brightness requirement increases from said low level to a maximum level.

8. The display of claim 1 wherein said first light source is a light device having less than all the colors red, green and blue as its light output and said second light source is a light device having at least the remaining colors from said red, green and blue as its light output.

9. The display of claim 8 wherein said control circuit is further operable for adjusting the color output of said first light source to achieve at least one criterion selected from the list of:

desired output color, desired output brightness level.

10. The display of claim 8 wherein said first light source is a red LED and wherein said second light source has a light output of green and blue.

11. The device of claim 10 wherein said second light source is biased toward blue and green, said second source selected from the list of CCFL, phosphor converted LED.

12. The method of constructing a backlighted display, said method comprising:

positioning a first light source having a first light emitting characteristic so that light coming from said first light source impacts a liquid crystal display;

(LCD);

positioning a second light source having a second light emitting characteristic so that light coming from said second light source mixes with said light coming from said first light source so as to control the color and intensity of the light impacting said LCD; and

connecting at least one of said first or second light sources in a manner to be controlled independently depending upon the output brightness desired from said LCD.

13. The method of claim 12 wherein said first light source is a first LED type and said second light source is a second LED type.

14. The method of claim 13 wherein said first LED type is a white diode and said second LED type is a RGB LED.

15. The method of claim 12 wherein said first light source is a RGB LED and said second light source is selected from the list of:

CCFL, phosphor converted LED.

16. The method of claim 12 wherein said first light source is a light device having less than all the colors red, green and blue as its light output and said second light source is a light device having at least the remaining colors from said red, green and blue as its light output.

17. The method of claim 16 further comprising:

adjusting the color output of said first light source to achieve at least one criterion selected from the list of;

desired output color, desired output brightness level.

18. A LCD backlighted display comprising:

a first light source having a first light emitting characteristic;

a second light source having a second light emitting characteristic, and means for adjusting one of said light sources relative to the other of said light sources dependant upon the output light intensity desired of said display.

19. The display of claim 18 wherein said first light source is a first LED type and said second light source is a second LED type.

20. The display of claim 18 wherein said first LED type is a diode emitting an essentially white light and said second LED type is a RGB LED.

21. The display of claim 18 wherein said first light source is a RGB LED and said second light source is selected from the list of:

CCFL, phosphor converted LED.

22. The display of claim 18 wherein said light intensity comprises a derived light color.