High resolution display system and method of using same

• US 5,543,819 A
• Filed: 11/19/1993
• Issued: 08/06/1996
• Est. Priority Date: 07/21/1988
• Status: Expired due to Term

• Current Assignee: Seiko Epson Corporation (Seiko Group)
• Original Assignee: Proxima Corporation (Ask ASA)
• Inventors: Farwell, Randall S., Shaw, Robert W., Marshall, Roger N.
• Primary Examiner(s): Weldon, Ulysses
• Assistant Examiner(s): Luu, Matthew
• Application Number:
  US08/155,480
• Time in Patent Office: 991 Days
• Field of Search: 345/88, 345/89, 345/147, 345/148, 345/149, 345/150, 345/152, 345/153
• US Class Current: 345/694
• CPC Class Codes: G02F 1/13473 for wavelength filtering or for colour display without the use of colour mosaic filters
• CPC Class Codes: G02F 1/1397 the twist being substantially higher than 90°, e.g. STN-, SBE-, OMI-LC cells
• 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 5/02 characterised by the way in which colour is displayed details of colour display specific for CRTs G09G1/28; specific for flat matrix panels other than liquid crystal displays G09G3/2003; specific for liquid crystal displays G09G3/3607
• 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
• CPC Class Codes: H04N 9/3188 Scale or resolution adjustment scaling in general G06T3/40; resolution modifying circuits for displays in general G09G5/391

Abstract

A method and system for producing a finely textured display image of a gradation of high color resolution color shading. The high color resolution system is adapted to be coupled to a relatively inexpensive high speed active matrix display panel employing single-bit LCD drivers and a plurality of sub-pixel elements. The system includes a sub-pixel activation circuit for generating single-bit digital signals for driving individual ones of the sub-pixel elements. A duty cycle circuit arrangement controls the sub-pixel activation circuit to cause desired ones of the sub-pixel elements to be activated selectively an average number of times over a large number of consecutive frame time intervals to generate sub-pixel images having desired perceived color shading levels. A fixed pattern generator responsive to a desired color shading level signal, controls the duty cycle circuit arrangement to activate sub-pixel elements to the desired perceived color shading levels and assigns color codes to groups of sub-pixel elements to produce color blending sub-pixel patterns that help to inhibit substantially color contouring between adjacent sub-pixel element images exhibiting a plurality of different color shading levels of a single primary color. The high resolution display system also includes a video interface module for coupling either RGB analog signals or RGB digital signals to the high speed LCD display panel.

Claims

1. A display control arrangement, comprising:

means responsive to a series of input intensity level signals indicative of individual ones of a large number of different incoming intensity levels for determining an individual unique one of another large number of a series of different M by N pixel matrix arrays of gray scale intensity level patterns corresponding to a given incoming intensity level;

each one of said patterns having two different desired gray scale intensity levels to help facilitate a blending gradation of color shading levels between pixel images of the same primary color but being generated in response to slightly different incoming intensity levels, each one of the two different gray scale intensity levels being less than its corresponding incoming intensity level, said two different gray scale intensity levels differing by at least one gray scale intensity level;

means for determining an individual one of said two different desired gray scale intensity levels for a selected pixel element in a determined pattern; and

means responsive to the determined desired gray scale intensity level of said two different gray scale intensity levels for said selected pixel element for causing the selected pixel element to be activated selectively to facilitate pixel image perception at the determined desired gray scale intensity level;

whereby said patterns of two different gray scale intensity levels for any single incoming intensity level signal cause adjacent pixel images of the same primary color but having somewhat different gray scale intensity levels to blend in a subtle gradation of intensity levels.

2. A display control arrangement, according to claim 1, wherein said pixel control means includes:

a plurality of pattern logic means for producing a plurality of color code signals indicative of desired gray scale color shading levels for at least two separate and distinct primary colors; and

bit map memory means responsive to said pattern logic means for storing said plurality of color code signals in a pattern array for helping to blend color shading levels for the same primary color.

3. A display control arrangement, according to claim 1, further comprising:

interface means coupled to said intensity level means for receiving desired color shading level signals and for formatting said desired color shading level signals to cause the individual color images in the plurality of different color images to be displayed by the display device.

4. A display control arrangement according to claim 1, further comprising:

intensity level means for determining whether or not individual pixel elements in a group of pixel elements are to be activated selectively an average number of times over a large number of consecutive frame time intervals to generate pixel images having substantially the same perceived gray scale color shading level N, where N is one of a large number of different gray scale shading levels; and

for determining whether or not individual pixel elements of another group of pixel elements are to be activated selectively an average number of times over said large number of consecutive frame time intervals to generate pixel images having substantially the same perceived gray scale color shading level M, where the gray scale shading level M is another one of said large number of different gray scale shading levels and can be perceived as a substantially different gray scale color shading level than said gray scale color shading level N;

duty cycle means for causing selected individual ones of the pixel elements in said group of pixel elements and individual ones of the pixel element in said another group of pixel elements to be activated selectively an average number of times over a large number of consecutive frame time intervals to generate pixel images defining color shading level patterns to substantially reduce contouring in perceived color shading level differences between pixel images disposed near one another.

5. A display control arrangement, according to claim 4, wherein said duty cycle means includes:

counter means for providing a series of intensity level averaging signals, said averaging signals being arranged in a certain arranged order to help prevent beat patterns in the plurality of different color images;

modifying means for causing said certain arranged order to be changed periodically; and

comparing means for determining whether said desired color shading level signal is greater than a corresponding intensity level averaging signal in said series of signals and for generating a single bit digital signal whenever said desired color shading level signal is greater than said corresponding intensity level averaging signal.

6. A display control arrangement according to claim 5, wherein said certain arranged order is changed during every line in the matrix of sub-pixel elements.

7. A display control arrangement, according to claim 6, wherein said certain arranged order is changed during every one of the frame time intervals in said large number of consecutive frame time intervals.

8. A display control arrangement according to claim 4, wherein said intensity level means includes:

means for determining an individual unique one of a series of duty cycle intensity level patterns, said patterns containing more than two duty cycle intensity levels, wherein at least some of said patterns are each arranged in an M by N pixel matrix array of intensity levels including at least two different duty cycle intensity levels differing by at least one duty cycle intensity level to reduce substantially contouring effects between adjacent pixel images of the same primary color but having different desired incoming intensity levels;

means responsive to the determined duty cycle intensity level pattern for determining an individual one of the duty cycle intensity levels of the determined pattern in accordance with the selected pixel element address location to generate a single duty cycle intensity level signal; and

wherein said duty cycle means includes means responsive to said single duty cycle level signal determined from the selected pattern for causing said selected pixel element to be activated selectively depending upon an overall average large number, substantially greater than eight consecutive frame cycles to cause a pixel image perception at said incoming desired intensity level;

whereby a subtle intensity gradation is achieved in the image to be displayed between groups of pixel images having somewhat different intensity levels.

9. A display control arrangement according to claim 8, wherein said series of duty cycle intensity level patterns includes at least two fixed composite pixel patterns.

10. A display control arrangement according to claim 9, wherein one of said fixed composite pixel patterns includes a group of pixel images having the same color intensity level.

11. A display control arrangement according to claim 9, wherein one of said fixed composite pixel pattern includes a group of pixel images having the same intensity level and a single pixel image having an intensity level substantially less than said group of pixel images.

12. A display control arrangement according to claim 9, wherein one of said fixed composite pixel pattern includes one area of pixel images having the same intensity level and another area of pixel images including at least a single pixel image having an intensity level substantially greater than the first mentioned area of pixel images.

13. A display control arrangement according to claim 9, wherein one of said fixed composite pixel pattern includes a group of pixel images having the same intensity level and a pair of pixel images having an intensity level substantially less than said group of pixel images.

14. A display control arrangement according to claim 9, wherein one of said fixed composite pixel pattern includes one area of pixel images having the same intensity level and another area of pixel images having at least a pair of pixel images having an intensity level substantially greater than the first-mentioned area of pixel images.

15. A display control arrangement according to claim 9, wherein one of said fixed composite pixel patterns includes a single pixel image at said desired color intensity level and a group of pixel images at another desired color intensity level substantially less than said desired color intensity level.

16. A display control arrangement according to claim 9, wherein one of said fixed composite panel patterns includes an area of pixel images including at least a single pixel image at said desired color intensity level and another area of pixel images at another desired color intensity level substantially greater than said desired color intensity level.

17. A display control arrangement according to claim 1, wherein each pattern is arranged in an M by N pixel array.

18. A display control arrangement according to claim 1, further including patterns having only three or four levels of said different desired gray scale intensity levels, where one gray scale level is assigned for the last mentioned pattern.

19. A display control arrangement according to claim 1, wherein the intensity gray scale levels include at least eight desired intensity levels.

20. A display control arrangement, comprising:

truth table means for storing a series of different patterns of groups of gray scale intensity levels, each pattern having at least three desired gray scale intensity levels, each one of said patterns corresponding individually to one of a series of incoming intensity levels, where the individual desired intensity levels within a given pattern are each generally smaller than their corresponding incoming intensity level each group of gray scale intensity levels including two different gray scale intensity levels differing by only one desired gray scale intensity level;

wherein only one of said desired gray scale intensity levels for each pattern is increased by only one gray scale intensity level for each corresponding increasing incoming intensity level value in said series of incoming intensity levels to help facilitate a blending gradation of color shading levels between pixel images of the same primary color but having different incoming intensity levels;

means responsive to a given incoming intensity level for determining one of said patterns for any given display frame cycle;

means for selecting one of said desired gray scale intensity levels of the determined pattern depending upon the address of a given pixel for said any given display frame cycle; and

means for activating said given pixel element at the selected desired gray scale intensity level for said any given display frame cycle;

whereby the color shading level patterns between pixel images having somewhat the same intensity level are blended in a subtle arrangement to substantially reduce contouring in the perceived color shading level differences whenever the last mentioned pixel images are displayed near one another.

21. A display control arrangement according to claim 20, wherein said series of different patterns includes a series of at least four different patterns.

22. A display control arrangement according to claim 20, wherein said series of different patterns includes a series of at least five different patterns.

23. A display control arrangement according to claim 20, wherein said series of incoming intensity levels includes at least eight incoming intensity levels.

24. A display control arrangement according to claim 20, wherein said series of incoming intensity levels includes at least thirty-one incoming intensity levels.

25. A display control arrangement according to claim 20, wherein said series of patterns are recurring over P number of contiguous incoming intensity levels.

26. A display control arrangement according to claim 25, wherein said P number is at least 5.

27. A method for controlling a displayed image to help reduce contouring between pixel images having somewhat different shading levels in the same primary color, comprising:

storing a series of different patterns of groups of gray scale intensity levels, each pattern having at least three desired gray scale intensity levels, each one of said patterns corresponding individually to one of a series of incoming intensity levels, where the individual desired intensity levels within a given pattern are each generally smaller than their corresponding incoming intensity level;

wherein each group of gray scale intensity levels includes two different gray scale intensity levels differing by only one desired gray scale intensity level;

wherein only one of said desired gray scale intensity levels for each pattern is increased by only one level corresponding to each corresponding increasing incoming intensity level value in said series of incoming intensity levels to help facilitate a blending gradation of color shading levels between pixel images of the same primary color but having different incoming intensity levels;

determining one of said patterns for any given display frame cycle in response to a given incoming intensity level;

selecting one of said desired gray scale intensity levels of the determined pattern depending upon the address of a given pixel element for said any given display frame cycle; and

activating said given pixel element at the selected desired gray scale intensity level for said any given display frame cycle;

whereby the color shading level patterns between pixel images having somewhat the same intensity level are blended in a subtle arrangement to substantially reduce contouring in the perceived color shading level differences whenever the last mentioned pixel images are displayed near one another.

28. A method according to claim 27, further comprising:

driving a display device having a matrix of sub-pixel elements to help reduce contouring lines within a plurality of different color images of a common primary color; and

generating energizing signals for driving individual ones of the sub-pixel elements on and off to form one of the plurality of different color images.

29. A method according to claim 28, further comprising:

actuating desired ones of the sub-pixel elements selectively an average number of times over a large number of consecutive frame time intervals to generate sub-pixel images having desired perceived color shading levels.