Method and system for driving a pixel

• US 20030103046A1
• Filed: 11/21/2002
• Published: 06/05/2003
• Est. Priority Date: 11/21/2001
• Status: Active Grant

• Current Assignee: Silicon Display Incorporated
• Original Assignee: Silicon Display Incorporated
• Inventors: Dunn, Ronnie N., Rogers, Gerald D.
• Granted Patent: US 6,985,164 B2
• Time in Patent Office: Days
• US Class Current: 345/204
• CPC Class Codes: G09G 2310/0221 with use of split matrices G09G3/3644 and G09G3/3666 take precedence
• CPC Class Codes: G09G 2310/0235 Field-sequential colour display
• CPC Class Codes: G09G 2320/0266 Reduction of sub-frame artefacts
• CPC Class Codes: G09G 3/2014 by modulation of the duration of a single pulse during which the logic level remains constant
• CPC Class Codes: G09G 3/2029 the sub-frames having non-binary weights
• CPC Class Codes: G09G 3/2033 with splitting one or more sub-frames corresponding to the most significant bits into two or more sub-frames
• CPC Class Codes: G09G 3/34 by control of light from an independent source
• CPC Class Codes: G09G 3/346 based on modulation of the reflection angle, e.g. micromirrors micromirrors devices per se G02B26/0833

Abstract

According to one embodiment of the invention, a method for displaying N-bit color on a plurality of pixels on a monitor includes, for each pixel, receiving a value indicative of one of a plurality of possible values for the level of intensity desired to be displayed on the pixel. The value is representable by N binary bits including a least significant bit. During a given time frame, the method includes providing an on state for the pixel for a continuous fractional portion of the given time frame. The fractional portion is indicative of the received value. The given time frame includes a fixed portion followed by a variable portion. For any of the possible values for the level of intensity, the time at which the pixel is turned on during the fixed portion, if at all, is independent of the least significant bit.

Claims

1. A method for displaying eight-bit color on a plurality of pixels on a monitor comprising:

for each pixel;

receiving a value indicative of one of a plurality of possible values for the level of intensity desired to be displayed on the pixel, the value representable by eight binary bits including a least significant bit;

during a given time frame, providing an on state for the pixel for a continuous fractional portion of the given time frame, the fractional portion being indicative of the received value, the given time frame comprising a fixed portion equal to approximately {fraction (224/255)} of the given time frame followed by a variable portion equal to approximately {fraction (31/255)} of the given time frame, wherein providing an on state for the pixel for a continuous fraction portion of the given time frame comprises, during the fixed time portion, changing the on or off state of the pixel, if at all, only at time intervals corresponding to approximately {fraction (32/255)} of the time frame, the on or off state of the pixel based solely on the three most significant bits of the value and independent of the least significant bit of the value; and

further comprising determining whether to turn the pixel off during the variable portion, including, during the variable time portion, turning the pixel off, if at all, only at each of a plurality of predetermined time intervals during the variable time portion, the time intervals during the variable time portion having a duration approximately equal to the time frame divided by 255.

2. A method for displaying ten-bit color on a plurality of pixels on a monitor comprising:

for each pixel;

receiving a value indicative of one of a plurality of possible values for the level of intensity desired to be displayed on the pixel, the value representable by ten binary bits including a least significant bit;

during a given time frame, providing an on state for the pixel for a continuous fractional portion of the given time frame, the fractional portion being indicative of the received value, the given time frame comprising a fixed portion equal to approximately {fraction (896/1023)} of the given time frame followed by a variable portion equal to approximately {fraction (127/1023)} of the given time frame, wherein providing an on state for the pixel for a continuous fraction portion of the given time frame comprises, during the fixed time portion, changing the on or off state of the pixel, if at all, only at time intervals corresponding to approximately {fraction (128/1023)} of the time frame, the on or off state of the pixel based solely on the three most significant bits of the value and independent of the least significant bit of the value; and

further comprising determining whether to turn the pixel off during the variable portion, including, during the variable time portion, turning the pixel off, if at all, only at each of a plurality of predetermined time intervals during the variable time portion, the time intervals during the variable time portion having a duration approximately equal to the time frame divided by 1023.

3. A method for displaying N-bit color on a plurality of pixels on a monitor comprising:

for each pixel;

receiving a value indicative of one of a plurality of possible values for the level of intensity desired to be displayed on the pixel, the value representable by N binary bits including a least significant bit;

during a given time frame, providing an on state for the pixel for a continuous fractional portion of the given time frame, the fractional portion being indicative of the received value, the given time frame comprising a fixed portion equal to approximately m/2^N−

1 of the given time frame followed by a variable portion equal to approximately

$\frac{2^N-m}{2^N-1}$

of the given time frame, wherein providing an on state for the pixel for a continuous fraction portion of the given time frame comprises, during the fixed time portion, changing the on or off state of the pixel, if at all, only at time intervals corresponding to approximately

$\frac{2^N-m+1}{2^N-1}$

of the time frame, the on or off state of the pixel independent of the least significant bit of the value;

further comprising determining whether to turn the pixel off during the variable portion, including, during the variable time portion, turning the pixel off, if at all, only at each of a plurality of predetermined time intervals during the variable time portion, the time intervals during the variable time portion having a duration approximately equal to the time frame divided by 2^N−

1; and

wherein m is between one and 2^N and m/2^N−

1 is between about ½ and

1.

4. The method of claim 3, wherein N is 12 and m is 3072.

5. The method of claim 3, wherein N is 14 and m is 12288.

6. A method for displaying N-bit color on a plurality of pixels on a monitor comprising:

for each pixel;

receiving a value indicative of one of a plurality of possible values for the level of intensity desired to be displayed on the pixel, the value representable by N binary bits including a least significant bit;

during a given time frame, providing an on state for the pixel for a continuous fractional portion of, the given time frame, the fractional portion being indicative of the received value, the given time frame comprising a fixed portion followed by a variable portion; and

wherein, for any of the possible values for the level of intensity, the time at which the pixel is turned on during the fixed portion, if at all, is independent of the least significant bit.

7. The method of claim 6, wherein providing an on state for the pixel for a continuous fractional portion of the given time frame comprises, during the fixed time portion, changing the on or off state of the pixel, if at all, only at each of a plurality of predetermined time intervals within the fixed portion, the time intervals each being greater than the length of the time frame divided by the number of the plurality of bits.

8. The method of claim 7, wherein each of the plurality of time intervals is the same.

9. The method of claim 8, wherein each of the plurality of time intervals is equal to approximately the time frame divided by N.

10. The method of claim 9, wherein the variable portion of the given time frame is equal to approximately the time frame divided by N.

11. The method of claim 7, wherein N is eight and the length of the each of the time intervals is approximately one eight of the given time frame.

12. The method of claim 7, wherein N is ten and the length of each of the time intervals is approximately {fraction (1/32)} of the given time frame.

13. The method of claim 7, wherein changing the on or off state of the pixel, if at all, only at each of a plurality of predetermined time intervals within the fixed portion comprises examining the two most significant bits of the value, and wherein the on or off state of the pixel is independent of bits of lesser significance than the two most significant bits.

14. The method of claim 7, wherein changing the on or off state of the pixel, if at all, only at each of a plurality of predetermined time intervals within the fixed portion comprises examining the three most significant bits of the value, and wherein the on or off state of the pixel is independent of bits of lesser significance than the two most significant bits.

15. The method of claim 11, wherein changing the on or off state of the pixel, if at all, only at each of a plurality of predetermined time intervals within the fixed portion comprises examining the two most significant bits of the value, and the on or off state of the pixel is independent of the five least significant bits of the value.

16. The method of claim 12, wherein changing the on or off state of the pixel, if at all, only at each of a plurality of predetermined time intervals within the fixed portion comprises examining the three most significant bits of the value, and the on or off state of the pixel is independent of the seven least significant bits of the value.

17. The method of claim 6, and further comprising turning the pixel off during the variable portion.

18. The method of claim 17, wherein turning the pixel off during the variable portion comprises, during the variable time portion, turning the pixel off only at each of a plurality of predetermined time intervals during the variable time portion, the time intervals during the variable time portion having a duration less than approximately the given time frame divided by N.

19. A method for driving a pixel, comprising:

providing a logic operable to,

receive an indication of a desired level of light intensity and storing the indication as one of a plurality of binary numbers, the binary numbers each having at least four bits and representing a particular level of light intensity during a frame time period, wherein each binary number has a plurality of most significant bits and a plurality of least significant bits, each of the most significant bits and each of the least significant bits associated with a particular time duration,

generate a plurality of continuous pulse chains each corresponding to a particular one of the binary numbers and having a designated start time within the frame time period, each of the continuous pulse chains having a duration represented by the most significant bits of the particular one of the binary numbers and concluding at a stop time, wherein any of the generated continuous pulse chains shorter in duration than another one of the generated continuous pulse chains has a later start time within the frame time period than the start time of the another one of the generated continuous pulse chains, and wherein the later start time is later than the start time by a time interval, the time interval equal to an integer multiple of the particular time duration of the least significant one of the most significant bits, and

generate a plurality of variable timing pulses each corresponding to the particular one of the binary numbers and having a start time within the frame time period that is immediately after the stop time of a corresponding one of the continuous pulse chains, the each of the plurality of variable timing pulses generated according to a time duration represented by the least significant bits of the particular one of the binary numbers;

receiving the indication at the logic;

storing the indication as the binary number; and

generating a single pulse having a duration indicative of the desired level of light intensity to drive the pixel to the particular level of light intensity.

20. The method of claim 19, wherein the stop time is within the later half of the frame time period.

21. The method of claim 19, wherein the stop time is at a time that is seven-eighths of the frame time period.

22. The method of claim 19, wherein the stop time of the each generated continuous pulse chain leaves a time period equal to a difference between the particular time duration associated with the least significant one of the most significant bits and the particular time duration of the least significant one of the least significant bits.

23. The method of claim 19, wherein the plurality of binary numbers each comprises eight bits and the plurality of most significant bits consists of the first three of the eight bits.

24. The method of claim 19, wherein the plurality of binary numbers each comprises ten bits and the plurality of most significant bits consists of the first three of the ten bits.

25. The method of claim 19, wherein the most significant one of the plurality of most significant bits is associated with the particular time duration that is approximately one half of the frame time period.

26. The method of claim 19, and further comprising:

dividing a display screen into a number of sectors equal to the number of the at least four bits, each of the sectors comprising a pixel;

driving the pixel of only one of the sectors with one of the variable timing pulses during the frame time period; and

driving another pixel of only another one of the sectors with the one of the variable timing pulses during a following frame time period.

27. A method for driving a pixel, comprising:

receiving an indication of a desired level of light intensity and storing the indication as one of a plurality of binary numbers, the plurality of binary numbers each having at least four bits and representing a particular level of light intensity during a frame time period, wherein each binary number has a plurality of most significant bits and a plurality of least significant bits, each of the most significant bits and each of the least significant bits associated with a particular time duration;

generating a plurality of continuous pulse chains each corresponding to a particular one of the binary numbers and having a designated start time within the frame time period, each of the continuous pulse chains having a duration represented by the most significant bits of the particular one of the binary numbers and concluding at a stop time, wherein any of the generated continuous pulse chains shorter in duration than another one of the generated continuous pulse chains has a later start time within the frame time period than the start time of the another one of the generated continuous pulse chains, and wherein the later start time is later than the start time by a time interval, the time interval equal to an integer multiple of the particular time duration of the least significant one of the most significant bits; and

generating a plurality of variable timing pulses each corresponding to the particular one of the binary numbers and having a start time within the frame time period that is immediately after the stop time of a corresponding one of the continuous pulse chains, the each of the plurality of variable timing pulses generated according to a time duration represented by the least significant bits of the particular one of the binary numbers.

28. The method of claim 27, wherein the stop time is within the later half of the frame time period.

29. The method of claim 27, wherein the stop time is at a time that is seven-eighth of the frame time period.

30. The method of claim 27, wherein the stop time of the each continuous pulse chain leaves a time period equal to a difference between the particular time duration associated with the least significant one of the most significant bits and the particular time duration of the least significant one of the least significant bits.

31. The method of claim 27, wherein the plurality of binary numbers each comprises eight bits and the plurality of most significant bits consists of the first three of the eight bits.

32. The method of claim 27, wherein the plurality of binary numbers each comprises ten bits, and the plurality of most significant bits consists of the first three of the eight bits.

33. The method of claim 27, and further comprising:

dividing a display screen into a number of sectors equal to the number of the at least four bits, each of the sectors comprising a pixel;

driving the pixel of only one of the sectors with one of the variable timing pulses during the frame time period; and

driving another pixel of only another one of the sectors with the one of the variable timing pulses during a following frame time period.

34. A system for driving a pixel, comprising:

a display unit having a display screen, the display screen comprising a plurality of pixels;

a logic unit coupled to the display screen and operable, when executed, to;

receive an indication of a desired level of light intensity and storing the indication as one of a plurality of binary numbers, the plurality of binary numbers each having at least four bits and representing a particular level of light intensity during a frame time period, wherein each binary number has a plurality of most significant bits and a plurality of least significant bits, each of the most significant bits and each of the least significant bits associated with a particular time duration;

generate a plurality of continuous pulse chains each corresponding to a particular one of the binary numbers and having a designated start time within the frame time period, each of the continuous pulse chains having a duration represented by the most significant bits of the particular one of the binary numbers and concluding at a stop time, wherein any of the generated continuous pulse chains shorter in duration than another one of the generated continuous pulse chains has a later start time within the frame time period than the start time of the another one of the generated continuous pulse chains, wherein the later start time is later than the start time by a time interval, the time interval equal to an integer multiple of the particular time duration of the least significant one of the most significant bits; and

generate a plurality of variable timing pulses each corresponding to the particular one of the binary numbers and having a start time within the frame time period that is immediately after the stop time of a corresponding one of the continuous pulse chains, the each of the plurality of variable timing pulses generated according to a time duration represented by the least significant bits of the particular one of the binary numbers.

35. The system of claim 34, wherein the stop time is at a time that is seven-eighth of the frame time period.

36. The system of claim 34, wherein the stop time of the each continuous pulse chain leaves a time period equal to a difference between the particular time duration associated with the least significant one of the most significant bits and the particular time duration of the least significant one of the least significant bits.

37. The system of claim 34, wherein the plurality of binary numbers each comprises eight bits and the plurality of most significant bits consists of the first three of the eight bits.

38. The system of claim 34, wherein the logic unit is further operable to:

divide a display screen into a number of sectors equal to the number of the at least four bits, each of the sectors comprising a pixel;

drive the pixel of only one of the sectors with one of the variable timing pulses during the frame time period; and

drive another pixel of only another one of the sectors with the one of the variable timing pulses during a following frame time period.