Liquid crystal display panel system and method of using same

• US 5,153,568 A
• Filed: 04/24/1991
• Issued: 10/06/1992
• Est. Priority Date: 07/21/1988
• Status: Expired due to Fees

• Current Assignee: Proxima Corporation (Ask ASA)
• Original Assignee: Proxima Corporation (Ask ASA)
• Inventors: Shaw, Robert W.
• Primary Examiner(s): Oberley, Alvin E.
• Assistant Examiner(s): HJERPE, RICHARD A
• Application Number:
  US07/690,700
• Time in Patent Office: 531 Days
• Field of Search: 340/701, 340/703, 340/765, 340/784, 340/793, 358/236, 358/241, 358/455, 359/36, 359/53, 359/54, 359/64, 359/66, 359/68
• US Class Current: 345/88
• CPC Class Codes: G09G 2300/023 Display panel composed of stacked panels
• CPC Class Codes: G09G 2320/0247 Flicker reduction other than flicker reduction circuits used for single beam cathode-ray tubes
• CPC Class Codes: G09G 2320/0276 for the purpose of adaptation to the characteristics of a display device, i.e. gamma correction
• CPC Class Codes: G09G 3/36 using liquid crystals
• CPC Class Codes: G09G 3/3607 for displaying colours or for displaying grey scales with a specific pixel layout, e.g. using sub-pixels display of colours in flat matrix panels other than liquid crystal displays G09G3/2003; grey scales specific for television H04N3/127
• CPC Class Codes: G09G 5/028 Circuits for converting colour display signals into monochrome display signals
• CPC Class Codes: H04N 2005/745 Control circuits therefor

Abstract

The display system includes a liquid crystal display panel unit having three different color components for each pixel of the resulting display. Each one of the individual color components of a pixel of the liquid crystal display panel unit is activated selectively by a corresponding one of a set of video processing units. Each video processing unit is responsive to a video signal from a conventional computer processor for causing the reproduction of a component of a colored image. Each video processing unit includes a translating arrangement for converting a component part of the computer generated video signal into a binary digital signal indicative of a single one of the color components for mixing with other color components to reproduce faithfully the computer generated color image.

Claims

1. A liquid crystal display panel system comprising:

a liquid crystal display panel unit for displaying computer-generated color images;

said liquid crystal display panel unit including a plurality of individual monochromatic liquid crystal display elements, each individual one of said plurality of elements being distinguishable from every other individual one of said plurality of elements by its color producing characteristics;

a video processing unit for interfacing said display panel unit to a computer processor unit and for producing a graduation in intensity of each individual one of said plurality of elements to produce a large number of color combinations said video processing unit including;

(a) means for receiving video clock signals for controlling the displaying of information in successive frames each defined by a frame time interval consisting of a predetermined number of said video clock signals;

(b) means for receiving intensity level signals, each one of said intensity level signals being indicative of a desired shading level for a given pixel image during the same portion of each frame time interval repetitively over a large number of successive frame time intervals;

(c) signals means responsive to said video clock signals for generating intensity level averaging signals arranged in recurring groups of predetermined ones of said averaging signals;

(d) said groups of intensity level averaging signals recurring during each frame time interval, each one of said groups consisting of another predetermined number of said averaging signals, said another number not being evenly divisible into said predetermined number of said video clock signals for causing different ones of said averaging signals to occur during successive frame time intervals for a given pixel element; and

(e) means for comparing individual ones of said intensity level signals and individual ones of said intensity level averaging signals for a given pixel element to cause the individual ones of said plurality of display elements to be activated selectively, whereby the average intensity level for each given pixel image over a large number of successive frames closely approximates said desired shading level.

2. A liquid crystal display panel system according to claim 1 including three monochromatic liquid crystal display panels.

3. A liquid crystal display panel system according to claim 2, wherein one of said monochromatic liquid crystal display panels generates images having a yellow color.

4. A liquid crystal display panel system according to claim 2, wherein one of said monochromatic liquid crystal display panels generates images having a magenta color.

5. A liquid crystal display panel system according to claim 7, wherein one of said monochromatic liquid crystal display panels generates images having a cyan color.

6. A liquid crystal display panel system according to claim 1, wherein said display panel unit includes an active matrix liquid crystal display panel.

7. A liquid crystal display panel system according to claim 1, wherein said panel unit includes three active matrix liquid crystal display panels.

8. A method of optimizing color shading with minimum flicker in a color liquid crystal display panel unit havung a plurality of primary color liquid crystal display element sets, each set with a different color producing characteristic, characterized by the steps of:

receiving video clock signals for controlling the displaying of information in successive frames each defined by a frame time interval consisting of a predetermined number of said video clock signals;

receiving intensity level signals, each one of said intensity level signals being indicative of a desired shading level for a given pixel image during the same portion of each frame time interval repetitively over a large number of successive frame time intervals;

generating intensity level averaging signals arranged in recurring groups of predetermined ones of said averaging signals;

causing different ones of said averaging signals to occur during successive frame time intervals for a given pixel element;

said predetermined ones of said averaging signals each having a numerical value;

comparing during each video clock signal the numerical values of individual ones of said intensity level averaging signals with individual ones of said intensity level signals for a given pixel element to cause the individual ones of said plurality of display element sets to be activated selectively, whereby the average intensity level for each given pixel image over a large number of successive frames closely approximate said desired shading level; and

generating a synchronized binary video output signal for each one of the liquid crystal display element sets to activate corresponding individual pixel elements in each of the liquid crystal display element sets.

9. A method according to claim 8 wherein the binary video output signal is generated whenever the numerical value of an individual one of said intensity level signals exceed the numerical value of an individual one of said intensity level averaging signals.

10. A method according to claim 8 wherein the intensity level averaging signals have recurring sequence values of 1, 3, 5 for four levels of color shading.

11. A method according to claim 8 wherein the intensity level averaging signals have recurring sequence values of 1, 5, 2, 4, 3, 0, 6 for eight levels of color shading.

12. A method according to claim 8 wherein the intensity level averaging signals have recurring sequence values of 0, 1, 2, 3, 4, 5, 6, 7, 10, 11, 12, 13, 14, 15, 16 for sixteen levels of color shading.

13. A method according to claim 8 wherein the intensity level averaging signals have recurring sequence values of 0, 1, 2, 4, 5, 7, 10, 11, 12, 13, 14.

14. A method according to claim 8 further comprising changing the predetermined sequence of said intensity level averaging signals periodically for substantially preventing repetitive activation of pixel elements in adjacent rows.

15. A system for displaying a large number of different color images, comprising:

display panel means for displaying computer-generated color images;

said display panel means including a plurality of electrically responsive pixel elements, each individual one of said plurality of pixel elements generating a pixel image having a distinguishable color shading level over a large number of successive frame time intervals;

video processing unit means for interfacing said display means to a computer processor unit and for causing individual ones of said pixel elements to be energized to produce a large number of shading levels;

said video processing unit means including;

means for receiving video clock signals for controlling the displaying of information in successive frames each defined by an individual one of said successive frame time intervals, said individual frame time interval consisting of a predetermined number of said video clock signals;

means for receiving intensity level signals, each one of said intensity level signals being indicative of a desired shading level for a given pixel image during the same portion of each frame time interval repetitively over said large number of successive frame time intervals;

signals means responsive to said video clock signals for generating intensity level averaging signals arranged in recurring groups of predetermined ones of said averaging signals;

said groups of intensity level averaging signals recurring during each frame time interval, each one of said groups consisting of another predetermined number of said averaging signals, said another number not being evenly divisible into said predetermined number of said video clock signals for causing different ones of said averaging signals to occur during successive frame time intervals for a given pixel element; and

means for comparing individual ones of intensity level signals and individual ones of intensity level averaging signals for a given pixel element to cause the individual ones of said plurality of pixel elements to be activated selectively, whereby the average intensity level for each given pixel image over a large number of successive frames closely approximates said desired shading level.

16. A system according to claim 15, wherein said display means is stacked liquid crystal panel means.

17. A system according to claim 15, wherein said display means is active matrix panel means.

18. A system according to claim 15, wherein said display means is passive matrix panel means.

19. A system according to claim 15, wherein said display means is active matrix color stripe means.

20. A system according to claim 15 wherein said frame time interval is a recurring frame time interval of a sufficient time duration to allow individual ones of said plurality of pixel elements to be energized in a random manner for controlling the average duty cycle of a pixel image to produce graduations in shading levels without substantially introducing flicker.

21. A system according to claim 20, wherein said frame time interval has a duration of about 33.3 milliseconds.

22. A system according to claim 16 wherein individual ones of the pixel images are combined by a color additive process to help facilitate the generation of a large number of different colors.

23. A system according to claim 16 wherein individual ones of the pixel images are combined by a color subtractive process to help facilitate the generation of a large number of different colors.

24. A system according to claim 22 wherein the color of an individual pixel image is selected from the colors consisting of red, green and blue.

25. A system according to claim 23, wherein the color of an individual pixel image is selected from the colors consisting of yellow, cyan and magenta.

26. A system for displaying a full color visual image, comprising:

panel means for displaying the full color visual image;

video processing unit means for energizing electrically said panel means to cause the full color image to be produced by said panel means and for causing said panel means to produce multiple color intensities for different colors, said video processing unit means including;

means for receiving video clock signals for controlling the displaying of the visual image in successive frames, each one of said frames being defined by a frame time interval, said frame time interval being defined by a frame time predetermined number of said video clock signals;

means for receiving intensity level signals, each one of said intensity level signal being indicative of a desired pixel image shading level for a given pixel element during a large number of successive frame time intervals;

means responsive to said video clock signals for producing a series of intensity level averaging signals arranged in recurring groups of said averaging signals;

said groups of intensity level averaging signals recurring during each frame time interval, each one of said groups including a shading level predetermined number of said averaging signals, said shading level predetermined number not being evenly divisible into said frame time predetermined number for causing different ones of said averaging signals to occur during successive frame time intervals for a given pixel element; and

means for comparing the individual ones of said intensity level signals and individual corresponding one of said intensity level averaging signals to develop an output signal to cause the display system to be activated selectively whenever the value of the intensity level signal is at least equal to the value of said corresponding intensity level averaging signal, whereby the average intensity level for each pixel image over a larger number of successive frame closely approximates said desired pixel image shading level.

27. A system for displaying a full color visual image, comprising:

panel means for displaying the full color visual image;

video processing unit means for energizing electrically said panel means to cause the full color image to be produced by said panel means and for causing said panel means to produce multiple color intensities for different colors, said video processing unit means including;

means for receiving video clock signals for controlling the displaying information in successive frames, each one of said frame being defined by a frame time interval, said frame time interval being defined by a frame time predetermined number of said video clock signals;

means for receiving intensity level signals, each one of said intensity level signals being indicative of a desired pixel image shading level for a given pixel element during a larger number of successive frame time intervals;

signal means responsive to said video clock signals for generating intensity level averaging signals arranged in recurring groups of said averaging signals;

said groups of intensity level averaging signals recurring during each frame time interval, each one of said groups including a shading level predetermined number of said averaging signals, said shading level predetermined number not being evenly divisible into said frame time predetermined number for causing different ones of said averaging signals to occur during successive frame time intervals for a given pixel element; and

means for comparing individual ones of said intensity level signals and individual ones of said intensity level averaging signals for a given pixel element to cause the display system to be activated selectively, whereby the average intensity level for each given pixel image over a larger number of successive frame closely approximates said desired pixel image shading level.

28. A system for displaying a full color visual image, comprising:

panel means for displaying the full color visual image, said panel means displaying a plurality of pixel images, in successive frames, each frame defined by a frame time interval;

video processing unit means for energizing electrically said panel means to cause the full color image to be produced by said panel means and for causing said panel means to produce multiple color intensities for different colors, said video processing unit means including;

means for supplying first number signals, for each pixel in a visual image, each one of said first number signals representing the color of the pixel image to be displayed at a given pixel element location;

means for supplying second number signals;

means for providing a count of the second number signals to a particular value on a repetitive basis;

means responsive to said individual ones of said first number signals and said means for providing a count for developing third signals for each given pixel element location in accordance with the characteristics of said first signals as compared to the output of said means for providing a count, said output simultaneously occurring for each such pixel element location; and

means for providing a video output signal for each said given pixel element location in accordance with the development of the third signals for the pixel images in each successive frame.

29. A system for displaying a full color visual image, comprising:

panel means for displaying the full color visual image;

video processing unit means for energizing electrically said panel means to cause the full color image to be produced by said panel means and for causing said panel means to produce multiple color intensities for different colors, said video processing unit means including;

means for providing intensity level signals to represent the intensity level of each displayable pixel in the visual display;

counting means for generating a series of pseudo intensity level signals indicative of a series of numbers ranging between a maximum value and a minimum value where each number in said series of numbers corresponds to a pseudo shading level for an individual displayable pixel forming part of the full color visual image;

means for comparing said intensity level signals and said pseudo intensity level signals for each displayable pixel location of each one of the frames in the visual display and for developing a video output signal when the intensity level signal is at least equal to a corresponding pseudo intensity level signal; and

means for causing said means for comparing to compare repeated each intensity level signal corresponding to a given pixel, with another ones of the pseudo intensity level signals corresponding to the given pixel for individual ones of a sufficiently large number of the successive frames to produce a desired average shading level corresponding substantially to the intensity level of said displayable pixel.

30. A method for displaying a full color visual image, comprising:

using panel means for displaying the full color visual image;

using video processing unit means for energizing electrically said panel means to cause the full color image to be produced by said panel means;

producing intensity level signals to represent the intensity level of each displayable pixel of the visual image;

generating a series of pseudo intensity level signals indicative of a series of numbers ranging between a maximum value and a minimum value, where each number in said series of numbers corresponds to a pseudo shading level for an individual displayable pixel forming part of the full color visual image;

comparing said intensity level signals and said pseudo intensity level signals for each displayable pixel location of each one of the frames in the visual display and for developing a video output signal when the intensity level signal is at least equal to a corresponding pseudo intensity level signal; and

comparing repeatedly each intensity level signal corresponding to a given pixel, with another one of the pseudo intensity level signals corresponding to the given pixel for individual ones of a sufficiently large number of the successive frames to produce a desired average shading level corresponding substantially to the intensity level of said displayable pixel.

31. A system for displaying a full color visual image, comprising:

panel means for displaying the full color visual image;

video processing unit means for energizing electrically said panel means to cause the full color image to be produced by said panel means and for causing said panel means to produce multiple color intensities for different colors, said video processing unit means including;

means for providing a visual display;

means for providing a raster scan of each pixel in the successive frames of the visual display;

means for providing for each displayable pixel in the raster scan of the successive frames of the visual display control signals representing the shading levels for each said displayable pixel;

means for causing the control signals representing the shading levels for each of the individual displayable pixels in the raster scan to be displayed in a substantially flicker free manner;

means for segregating the successive frames into groups, each such group having a given number of successive frames; and

said means providing control signals developing a video signal selectively for individual pixels only an average number of times in any group of successive frames and to develop said video signal in different frames in successive groups on a random basis.

32. A system for displaying a full color visual image, comprising:

panel means for displaying the full color visual image;

video processing unit means for energizing electrically said panel means to cause the full color image to be produced by said panel means and for causing said panel means to produce multiple color intensities for different colors, said video processing unit means including;

intensity level averaging means for generating a predetermined set of recurring averaging signals indicative of a given number of different intensity level, said signals within said set being generated individually seriatim;

means for receiving a level determining signal corresponding to a selected one of said different intensity level recurring signals said level determining signal being indicative of a desired intensity level for a given pixel element image;

means for comparing said level determining signal and individual ones of the recurring averaging signals to cause said display system to be activated selectively;

means for receiving recurring display frame determining signals to cause said intensity level means to generate the next one of its averaging signals, said predetermined set of recurring signals defining an averaging time interval not being evenly divisible into each one of the frame time intervals to cause the averaging time intervals and the frame time intervals to be asynchronous relative to one another; and

wherein said means for comparing being responsive to said frame determining signals during the same portion of each frame time interval, whereby the average intensity level over a larger number of frames closely approximates a selected intensity level.

33. A system for displaying a full color visual image, comprising:

panel means for displaying the full color visual image;

video processing unit means for energizing electrically said panel means to cause the full color image to be produced by said panel means and for causing said panel means to produce multiple color intensities for different colors, said video processing unit means including;

means for receiving video clock signals for controlling the displaying of the visual image in successive frames, each one of said frames being defined by a frame time interval, said frame time interval being defined by a frame time predetermined number of said video clock signals;

means for receiving intensity level signals, each one of said intensity level signal being indicative of a desired pixel image shading level for a given pixel element during a large number of successive frame time intervals;

means for generating a series of intensity level averaging signals arranged in recurring groups of said averaging signals;

means for causing different ones of said averaging signals to occur during successive frame time intervals for a given pixel element; and

means for comparing the individual ones of said intensity level signals and individual corresponding ones of said intensity level averaging signals for a given pixel element to develop an output signal to cause a display system to be activated selectively, whenever the value of the intensity level signal is at least equal to the value of said corresponding intensity level averaging signal whereby the average intensity level for each given pixel image over a large number of successive frames closely approximates said desired image shading level.

34. In a display system for producing a full color image composed of a group of pixels, over a large number of successive frame time intervals, video processing unit means comprising:

means for receiving shaded color signals indicative of desired color intensity levels of individual ones of the pixels forming the full color image;

means for generating a series of shading level averaging signals to help inhibit flicker in the full color image displayed over the large number of successive frame time intervals;

comparator means responsive to said shaded color signals and to said averaging signals for developing video output signals indicative of the full color image to be displayed whenever the value of an individual one of said shaded color signals is at least equal to the corresponding value of an individual one of said averaging signals during individual frame time intervals in the large number of successive frame time intervals so that said video output signals have a duty cycle over the large number of successive frame time intervals to form the full color image in a substantially flicker free manner.

35. In a display system for producing a full color image, video processing unit means in accordance with claim 34, wherein said means for generating is a signal generator that produces a pre-set recurring non-sequential set of averaging signals.

36. In a display system for producing a full color image, video processing unit means in accordance with claim 35, wherein each one of said pre-set recurring non-sequential set of averaging signals have substantially different values relative to one another.

37. In a display system for producing a full color image, a video processing unit means in accordance with claim 34, wherein said averaging signals are a recurring set of averaging signals.

38. In a display system for producing a full color image, video processing unit means in accordance with claim 35, wherein said signal generator is reset at least once during each frame time interval in the large number of successive frame time intervals.

39. A system for displaying a full color visual image, comprising:

panel means for displaying the full color visual image;

video processing unit means for energizing electrically said panel means to cause the full color image to be produced by said panel means and for causing said panel means to produce multiple color intensities for a different color, said video processing unit means including;

means for receiving video clock signals for controlling the displaying of the visual image in successive frames, each one of said frames being defined by a frame time interval, said frame time interval being defined by a frame time predetermined number of said video clock signals;

means for receiving intensity level signals, each one of said intensity level signal being indicative of a desired pixel image shading level for a given pixel element during a large number of successive frame time intervals;

means for generating a series of intensity level averaging signals arranged in recurring groups of said averaging signals;

means for causing different ones of said averaging signals to occur during successive frame time intervals for a given pixel element; and

means for comparing the individual ones of said intensity level signals and individual corresponding ones of said intensity level averaging signals for a given pixel element to develop an output signal to cause a display system to be activated selectively, whenever the value of the intensity level signal is greater than the value of said corresponding intensity level averaging signal whereby the average intensity level for each given pixel image over a large number of successive frames closely approximates said desired image shading level.

40. A system for displaying a full color visual image, comprising:

panel means for displaying the full color visual image;

video processing unit means for energizing electrically said panel means to cause the full color image to be produced by said panel means and for causing said panel means to produce multiple color intensities for a different color, said video processing unit means including;

means for receiving video clock signals for controlling the displaying of the visual image in successive frames, each one of said frames being defined by a frame time interval, said frame time interval being defined by a frame time predetermined number of said video clock signals;

means for receiving intensity level signals, each one of said intensity level signal being indicative of a desired pixel image shading level for a given pixel element during a large number of successive frame time intervals;

means for generating a series of intensity level averaging signals arranged in recurring groups of said averaging signals;

means for causing different ones of said averaging signals to occur during successive frame time intervals for a given pixel element; and

means for comparing the individual ones of said intensity level signals and individual corresponding ones of said intensity level averaging signals for a given pixel element to develop an output signal to cause a display system to be activated selectively, whenever the value of the intensity level signal is less than the value of said corresponding intensity level averaging signal whereby the average intensity level for each given pixel image over a large number of successive frames closely approximates said desired image shading level.

41. In a display system for producing a full color image composed of a group of pixels, over a large number of successive frame time intervals, video processing unit means comprising:

means for receiving intensity level signals, each one of said intensity level signal being indicative of a desired pixel image shading level for a given pixel element during a large number of successive frame time intervals;

means for generating a series of intensity level averaging signals arranged in recurring groups of said averaging signals;

means for causing different ones of said averaging signals to occur during successive frame time intervals for a given pixel element; and

means for comparing the individual ones of said intensity level signals and individual corresponding ones of said intensity level averaging signals for a given pixel element to develop an output signal to cause a display system to be activated selectively, whenever the value of the intensity level signal is at least equal to the value of said corresponding intensity level averaging signal whereby the average intensity level for each given pixel image over a large number of successive frames closely approximates said desired image shading level.

42. In a display system for producing a full color image, video processing unit means in accordance with claim 41, wherein said means for generating is a signal generator that produces a pre-set recurring non-sequential set of averaging signals.

43. In a display system for producing a full color image, video processing unit means in accordance with claim 42, wherein each one of said pre-set recurring non-sequential set of averaging signals have substantially different values.

44. In a display system for producing a full color image, video processing unit means in accordance with claim 42 wherein said signal generator is reset at least once during each frame time interval in the large number of successive frame time intervals.