Adaptive overdrive and backlight control for TFT LCD pixel accelerator

• US 20040012551A1
• Filed: 09/30/2002
• Published: 01/22/2004
• Est. Priority Date: 07/16/2002
• Status: Abandoned Application

• Current Assignee: Silicon Monitor, Inc.
• Original Assignee: Silicon Monitor, Inc.
• Inventors: Ishii, Takatoshi
• Application Number:
  US10/262,618
• Publication Number:
  US 20040012551A1
• Time in Patent Office: Days
• US Class Current: 345/87
• CPC Class Codes: G09G 2310/0237 Switching ON and OFF the backlight within one frame
• CPC Class Codes: G09G 2310/08 Details of timing specific for flat panels, other than clock recovery
• CPC Class Codes: G09G 2320/0252 Improving the response speed
• CPC Class Codes: G09G 2320/0257 Reduction of after-image effects
• CPC Class Codes: G09G 2320/0261 in the context of movement of objects on the screen or movement of the observer relative to the screen
• CPC Class Codes: G09G 2320/0285 using tables for spatial correction of display data
• CPC Class Codes: G09G 2320/0686 with two or more screen areas displaying information with different brightness or colours
• CPC Class Codes: G09G 2340/16 Determination of a pixel data signal depending on the signal applied in the previous frame
• CPC Class Codes: G09G 3/3406 Control of illumination source illumination devices structurally associated with liquid crystal cells G02F1/1336
• CPC Class Codes: G09G 3/3648 using an active matrix G09G3/367 - G09G3/3696 take precedence
• CPC Class Codes: G09G 5/14 Display of multiple viewports

Abstract

A configuration/apparatus to drive emphasized data to an LCD screen, including enhancing frame difference data with compensation and enhancement factors. These factors can consider a backlight phase input from a variable backlight control system.

Claims

1. An apparatus for generating a set of drive data from a set of current input data, said set of drive data intended for output on a Liquid Crystal Display, said apparatus comprising:

a data emphasizer which determines a variation between a set of previous input data and said set of current input data, said variation the basis for generating said set of drive data.

2. An apparatus according to claim 1 further comprising:

a backlight control mechanism, said backlight control mechanism providing a backlight phase signal indicating the phase of a backlight provided to said Liquid Crystal Display, said backlight phase signal and said variation utilized to generate said set of drive data.

3. An apparatus according to claim 1 wherein said data emphasizer comprises:

a frame buffer configured to store a first portion of said set of previous input data until said set of drive data is generated and configured afterwards to store a first portion of said set of current input data in anticipation of generating a next set of drive data; and

a conversion table, said conversion table coupled to said frame buffer to receive said first portion of said set of previous input data, said conversion table further configured to receive said first portion of said set of current input data and generate a first portion of a set of over-drive data therefrom.

4. An apparatus according to claim 3 wherein said data emphasizer further comprises:

an intermediate buffer for temporarily storing a second portion of said set of current input data;

a multiplexer configured to select as output one of data from said intermediate buffer and a second portion of said set of over-drive data; and

a comparator comparing said first portion of said set of current input data with said first portion of said set of previous input data, wherein if said comparator determines said first portions are equal, said comparator causing said multiplexer to select said data from said intermediate buffer, and if said comparator determines that said first portions are not equal, then causing said multiplexer to select said second portion of said over-drive data.

5. An apparatus according to claim 3 wherein said emphasizing factor varies dynamically over the area of the liquid crystal display, further wherein said emphasizing factor is a function of the response time of said liquid crystal display, said set of current input data and said set of previous input data.

6. An apparatus according to claim 3 wherein said frame buffer stores said set of previous input data in an RGB format.

7. An apparatus according to claim 3 wherein said frame buffer stores said set of previous input data in a compressed format.

8. An apparatus according to claim 7 wherein said compressed format is YCrCb.

9. An apparatus according to claim 3 further comprising:

a windowing mechanism configured to select a window of said liquid crystal display, said window a sub-set of the area of output of said liquid crystal display, wherein said set of over-drive data is the same as said set of current input data where said set of current input data is destined to be output outside of said window and is emphasized by said data emphasizer using said emphasizing factor where said set of current input data is destined to be output inside of said window.

10. An apparatus according to claim 1 wherein said data emphasizer comprises:

a frame buffer configured to store as frame buffer data one of a first portion of said set of previous input data and a previous modified frame buffer data until said set of drive data is generated and configured afterwards to store a frame buffer data one of a first portion of said set of previous input data and a first portion of current modified frame buffer data in anticipation of generating a next set of drive data; and

a conversion table, said conversion table coupled to said frame buffer to receive said frame buffer data, said conversion table further configured to receive said first portion of said set of current input data and generate a first portion of a set of adaptive over-drive data and modified frame buffer data therefrom.

11. An apparatus according to claim 10 wherein said data emphasizer further comprises:

an intermediate buffer for temporarily storing a second portion of said set of current input data;

a first multiplexer configured to select as output one of data from said intermediate buffer and a second portion of said set of adaptive over-drive data; and

a comparator comparing said first portion of said set of current input data with said frame buffer data, wherein if said comparator determines they are equal, said comparator causing said first multiplexer to select said data from said intermediate buffer, and if said comparator determines that they are not equal, then causing said first multiplexer to select said second portion of said adaptive over-drive data.

12. An apparatus according to claim 11 further comprising:

a second multiplexer selecting said frame buffer data to be written with previous modified frame buffer data if said comparator determines said first portion of said set of current input data and said frame buffer data are not equal, and to be written with said first portion of said set of previous input data if said comparator determines said first portion of said set of current input data and said frame buffer data are equal.

13. An apparatus according to claim 10 wherein said adaptive factor and said modify factor varies dynamically over the area of the liquid crystal display, further wherein said adaptive factor and said modify factor are a dynamic function of the response time of said liquid crystal display, said set of current input data and said set of previous input data.

14. An apparatus according to claim 10 wherein said frame buffer stores said set of previous input data in an RGB format.

15. An apparatus according to claim 10 wherein said frame buffer stores said set of previous input data in a compressed format.

16. An apparatus according to claim 15 wherein said compressed format is YCrCb.

17. An apparatus according to claim 10 further comprising:

a windowing mechanism configured to select a window of said liquid crystal display, said window a sub-set of the area of output of said liquid crystal display, wherein said set of over-drive data is the same as said set of current input data where said set of current input data is destined to be output outside of said window and is emphasized by said data emphasizer using said adaptive factor where said set of current input data is destined to be output inside of said window.

18. An apparatus according to claim 2 wherein said data emphasizer comprises:

a frame buffer configured to store as frame buffer data one of a first portion of said set of previous input data and a previous modified frame buffer data until said set of drive data is generated and configured afterwards to store a frame buffer data one of a first portion of said set of previous input data and a first portion of current modified frame buffer data in anticipation of generating a next set of drive data; and

a conversion table, said conversion table coupled to said frame buffer to receive said frame buffer data, said conversion table further configured to receive said first portion of said set of current input data and to receive said backlight phase signal and generate a first portion of a set of adaptive over-drive data and modified frame buffer data therefrom.

19. An apparatus according to claim 18 wherein said data emphasizer further comprises:

an intermediate buffer for temporarily storing a second portion of said set of current input data;

a first multiplexer configured to select as output one of data from said intermediate buffer and a second portion of said set of adaptive over-drive data; and

a comparator comparing said first portion of said set of current input data with said frame buffer data, wherein if said comparator determines they are equal, said comparator causing said first multiplexer to select said data from said intermediate buffer, and if said comparator determines that they are not equal, then causing said first multiplexer to select said second portion of said adaptive over-drive data.

20. An apparatus according to claim 19 further comprising:

a second multiplexer selecting said frame buffer data to be written with previous modified frame buffer data if said comparator determines said first portion of said set of current input data and said frame buffer data are not equal, and to be written with said first portion of said set of previous input data if said comparator determines said first portion of said set of current input data and said frame buffer data are equal.

21. An apparatus according to claim 18 wherein said adaptive factor and said modify factor varies dynamically over the area of the liquid crystal display, further wherein said adaptive factor and said modify factor are a dynamic function of the response time of said liquid crystal display, said set of current input data, said set of previous input data and said backlight phase signal.

22. An apparatus according to claim 18 wherein said frame buffer stores said set of previous input data in an RGB format.

23. An apparatus according to claim 18 wherein said frame buffer stores said set of previous input data in a compressed format.

24. An apparatus according to claim 23 wherein said compressed format is YCrCb.

25. An apparatus according to claim 20 further comprising:

a windowing mechanism configured to select a window of said liquid crystal display, said window a sub-set of the area of output of said liquid crystal display, wherein said set of over-drive data is the same as said set of current input data where said set of current input data is destined to be output outside of said window and is emphasized by said data emphasizer using said adaptive factor where said set of current input data is destined to be output inside of said window.

31. An apparatus according to claim 1 wherein said set of current and set of previous input data are from a processing engine.

32. An apparatus according to claim 31 wherein said processing engine is part of a display controller.

33. An apparatus according to claim 31 wherein said processing engine is a component of a computer system.

26. An apparatus for controlling a backlight for a liquid crystal display, comprising:

means to flash said backlight on and off at least more than once during any one frame interval of said liquid crystal display output; and

means for synchronizing between frames displayed on said liquid crystal display.

27. An apparatus according to claim 26 wherein said means to flash includes:

means to control the period over which said backlight is flashed; and

means to generate at least one backlight on control signal.

28. An apparatus for controlling a backlight for a liquid crystal display, comprising:

means to flash said backlight on and off during any one frame interval of said liquid crystal display output;

means for synchronizing between frames displayed on said liquid crystal display;

means to adjust the phase of said flashing backlight; and

means to output a phase signal representative of said phase.

29. An apparatus according to claim 28 wherein said phase signal is utilized in generating drive data to drive said liquid crystal display.

30. An apparatus for controlling a backlight for a liquid crystal display, comprising:

means to flash said backlight on and off during any one frame interval of said liquid crystal display output; and

means for synchronizing between frames displayed on said liquid crystal display wherein said backlight is from a Xenon strobo flash source.