Backlight variation compensated display

1. A liquid crystal display having compensation for varying brightness levels, comprising:

a dimmable back-light configured to provide varying brightness levels;

a display panel, optically coupled to the back-light for receiving illumination therefrom, and whose properties depend upon the varying back-light brightness levels and having a first input configured to receive a compensating signal proportional to the varying back-light levels, the first input coupled to a common terminal of the display panel adapted to receive a common voltage;

an electrical circuit configured to receive back-light brightness level information that is proportional to an ambient light level;

a non-volatile memory configured to store values of an optimum display panel compensating signal as a function of back-light brightness levels; and

a controller coupled to the memory, the electrical circuit and the display panel, the controller configured to retrieve from the memory the optimum display panel compensating signal corresponding to the back-light brightness level received from the electrical circuit, and transmit such optimum display panel compensating signal to the first input.

2. The display of claim 1 , wherein output of the dimmable back-light can be varied over a dimming range of approximately 2 to 1 or greater.

3. The display of claim 1 , wherein output of the dimmable back-light can be varied over a dimming range of up to at least 50,000 to 1.

4. The display of claim 1 , wherein the display panel further comprises thin film transistors that are photosensitive.

5. The display of claim 1 , wherein the dimmable back-light comprises light emitting diodes.

6. The display of claim 1 , wherein the electrical circuit comprises a back-light lamp driver and the back-light brightness information is proportional to a light producing drive signal provided to the back-light by the back-light lamp driver.

7. The display of claim 1 , wherein the electrical circuit comprises a photodetector in a light path of the back-light.

8. A method for compensating a liquid crystal display for varying display brightness level, comprising:

reading a brightness value that varies over time in proportion to a sensed ambient light level;

determining a display compensating signal value corresponding to the read brightness value; and

automatically applying the display compensating signal value to the display by sending a value proportional to the display compensating signal to a common electrode of the display.

9. The method of claim 8 , wherein determining comprises, retrieving from a look-up table, the compensating signal corresponding to the read brightness value.

10. The method of claim 8 , wherein reading comprises, measuring an actual brightness value of a back-light optically coupled to the display.

11. The method claim 8 including: reading a brightness value that varies over time in proportion to the projected image size.

12. A liquid crystal display having compensation for varying brightness levels, comprising:

a dimmable back-light configured to provide varying back-light brightness levels in proportion to sensed ambient light intensities;

a display panel, optically coupled to the back-light and configured to receive illumination therefrom, and whose flicker properties depend upon the varying back-light brightness level, and having a first input for receiving a compensating signal;

an electrical circuit for receiving a real time flicker level of the display panel and the sensed ambient light intensities; and

a controller coupled to the electrical circuit and the display panel, the controller configured to receive from the electrical circuit a signal related to both the display flicker level and the sensed ambient light intensities and configured to determine based thereon a display panel compensating signal corresponding to the observed flicker level and transmit such display panel compensating signal to the first input.

13. The display of claim 12 , wherein the electrical circuit comprises a sensor optically coupled to the display panel and electrically coupled to the controller, and adapted to measure the real-time flicker level of the display panel and provide such information to the controller.

14. The display of claim 13 , wherein the sensor is integrated with the display panel.

15. A method for compensating a liquid crystal display for varying display brightness level, comprising:

electronically measuring the real time display flicker and a brightness value that varies over time in proportion to an ambient light level;

electronically determining a display compensating signal value that varies with the measured display flicker; and

automatically applying the display compensating signal value to an input of the display for receiving a common electrode voltage to reduce said flicker.

16. The method of claim 15 , wherein the compensating signal is applied to Gamma voltages of the display, effectively changing V COM .

17. The method of claim 15 , further comprising prior to the determining step, evaluating whether the real time display flicker obtained in the measuring step has changed.

18. The method of claim 15 , further comprising prior to the measuring step, illuminating the display with light obtained from an LED back-light source.