Nonlinearly converting a signal to compensate for non-uniformities and degradations in a display

• US 6,525,683 B1
• Filed: 09/19/2001
• Issued: 02/25/2003
• Est. Priority Date: 09/19/2001
• Status: Active Grant

• Current Assignee: Intel Corporation
• Original Assignee: Intel Corporation
• Inventors: Gu, Gong
• Primary Examiner(s): Tokar, Michael
• Assistant Examiner(s): Nguyen, Khai
• Application Number:
  US09/956,272
• Time in Patent Office: 524 Days
• Field of Search: 341/138, 341/139, 341/140, 341/144, 345/38, 345/39, 345/55, 345/90
• US Class Current: 341/140
• CPC Class Codes: G09G 2310/027 Details of drivers for data electrodes, the drivers handling digital grey scale data, e.g. use of D/A converters
• 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 2320/0285 using tables for spatial correction of display data
• CPC Class Codes: G09G 2320/043 Preventing or counteracting the effects of ageing
• CPC Class Codes: G09G 2320/048 using evaluation of the usage time
• 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 3/2081 with combination of amplitude modulation and time modulation space and time error diffusion G09G3/2066
• CPC Class Codes: G09G 3/3216 using a passive matrix
• CPC Class Codes: H03M 1/664 Non-linear conversion not otherwise provided for in subgroups of H03M1/66

Abstract

A digital signal directed to a display (e.g., a plurality of display elements forming an array of display elements) may be converted into an analog signal using a nonlinear relationship. In one embodiment, a drive signal may be provided to at least one display element of the array of display elements in response to calibration data. Embedding the calibration data using the nonlinear relationship, the amplitude of the drive signal may be determined in order to control a perceptible output from the at least one display element of the array of display elements. Thus, a compensation for initial non-uniformity degradation over time, and/or non-uniform degradation may be provided to the at least one display element of the array of display elements. The nonlinear relationship reduces the number of discrete calibration data levels required to avoid perceptible contrast among neighboring pixels that leads to contouring effects. Optionally, a gamma correction may also be simultaneously provided with the compensation by adjusting the duration of the drive signal directed to the at least one display element of the array of display elements.

Claims

1. A method, comprising:

converting a digital signal directed to a plurality of display elements forming an array of display elements into an analog signal;

digitally adjusting the magnitude of the analog signal based on a nonlinear relationship that forms a non-uniform pulse interval clock from a uniform pulse interval clock; and

providing the analog signal to at least one display element of the array of display elements.

2. The method of claim 1, including modulating the magnitude of the analog signal to control a perceptible output from the at least one display element of the array of display elements.

3. A method comprising:

converting a digital signal directed to a plurality of display elements forming an array of display elements into an analog signal using a nonlinear relationship;

providing the analog signal to at least one display element of the array of display elements;

modulating the magnitude of the analog signal to control a perceptible output from the at least one display element of the array of display elements; and

defining an adjustable range to establish a minimum level of the magnitude and a maximum level of the magnitude for the analog signal, and an increment size to establish a minimum amount of adjustment applied to the analog signal while calibrating the magnitude of the analog signal.

4. The method of claim 3, including mapping the minimum level of the magnitude of the adjustable range to an offset in a transfer function defining said nonlinear relationship while modulating the magnitude of the analog signal.

5. The method of claim 4, including using the adjustable range as a ratio of a maximum level of compensation derived from calibration data to a minimum level of compensation derived from the calibration data to control the perceptible output from the at least one display element of the array of display elements.

6. The method of claim 3, including establishing the nonlinear relationship to perform a conversion of the digital signal into the analog signal, said nonlinear relationship obtained from one or more human-vision related features, wherein said adjustable range and the increment size is selected to conform with the one or more human-vision related features associated with the array of display elements.

7. A method comprising:

converting a digital signal directed to a plurality of display elements forming an array of display elements into an analog signal using a nonlinear relationship;

providing the analog signal to at least one display element of the array of display elements;

modulating the magnitude of the analog signal to control a perceptible output from the at least one display element of the array of display elements;

generating from timing information associated with the plurality of display elements forming the array of display elements, a first series of pulses having a first pulse interval between a first pair of adjacent pulses and at least one second pulse interval between a second pair of adjacent pulses, said first pulse interval being different than the at least one second pulse interval; and

using the first series of pulses to generate a second series of pulses directed to the at least one display element of the array of display elements.

8. The method of claim 7, including receiving video data to determine the width of the second series of pulses in order to map the video data to the output intensity of the at least one display element of the array of display elements.

9. The method of claim 8, including receiving calibration data to:

modulate the amplitude of the second series of pulses to control overall brightness of the array of display elements; and

compensate for a perceptible degradation in the at least one display element of the array of display elements and a perceptible non-uniformity among the plurality of display elements.

10. The method of claim 8, further including adjusting a duration of illumination of the at least one display element of the array of display elements based on the width of the second series of pulses to map the video data to the perceptible output from the at least one display element of the array of display elements.

11. The method of claim 7, further including modulating the width of the second series of pulses for a gamma correction in the array of display elements while modulating the amplitude of the second series of pulses to calibrate the array of display elements.

12. A method comprising:

converting a digital signal directed to a plurality of display elements forming an array of display elements into an analog signal using a nonlinear relationship;

providing the analog signal to at least one display element of the array of display elements;

modulating the magnitude of the analog signal to control a perceptible output from the at least one display element of the array of display elements; and

using calibration data based on the nonlinear relationship in order to adjust the magnitude of the analog signal.

13. The method of claim 12, including modulating the magnitude of the analog signal in response to the calibration data to compensate for a perceptible degradation in the at least one display element of the array of display elements and a perceptible non-uniformity among the plurality of display elements.

14. The method of claim 13, including extracting an indication from the calibration data to determine a level of compensation to calibrate the perceptible output of the at least one display element of the array of the display elements.

15. The method of claim 14, including deriving from the calibration data said indication using a difference between first and second levels of compensation for adjacent display elements of the array of the display elements, said difference is compared to a predetermined fraction to determine whether to adjust the magnitude of the analog signal.

16. An apparatus, comprising:

a signal converter to convert a digital signal directed to a plurality of display elements forming an array of display elements into an analog signal; and

a combiner coupled to the signal converter to digitally adjust the magnitude of the analog signal based on a nonlinear relationship that forms a non-uniform pulse interval clock from a uniform pulse interval clock to provide the analog signal to at least one display element of the array of display elements.

17. The apparatus of claim 16, wherein the interface further comprises a driver coupled to the at least one display element of the array of display elements, said driver directs the analog signal to the at least one display element of the array of display elements.

18. The apparatus of claim 16, wherein the signal converter comprises a digital-to-analog converter.

19. An apparatus, comprising:

a signal converter to convert a digital signal directed to a plurality of display elements forming an array of display elements into an analog signal using a nonlinear relationship, wherein the digital-to-analog converter uses calibration data to determine the magnitude of the analog signal; and

an interface coupled to the signal converter to provide the analog signal to at least one display element of the array of display elements.

20. An apparatus comprising:

a signal converter to convert a digital signal directed to a plurality of display elements forming an array of display elements into an analog signal using a nonlinear relationship, wherein the signal converter defines an adjustable range to establish a minimum level of the magnitude and a maximum level of the magnitude for the analog signal, and an increment size to establish a minimum amount of adjustment applied to the analog signal while calibrating the magnitude of the analog signal; and

an interface coupled to the signal converter to provide the analog signal to at least one display element of the array of display elements.

21. The apparatus of claim 20, wherein the signal converter maps the minimum level of the magnitude of the adjustable range to an offset in a transfer function defining said nonlinear relationship while modulating the magnitude of the analog signal.

22. The apparatus of claim 21, wherein the signal converter uses the adjustable range as a ratio of a maximum level of compensation derived from calibration data to a minimum level of compensation derived from the calibration data to control the perceptible output from the at least one display element of the array of display elements.

24. The apparatus of claim 22, wherein the signal generator receives video data to determine the width of the second series of pulses in order to map the video data to the output intensity of the at least one display element of the array of display elements.

25. The apparatus of claim 24, wherein the signal generator adjusts a duration of illumination of the at least one display element of the array of display elements based on the width of the second series of pulses to map the video data on the perceptible output from the at least one display element of the array of display elements.

23. An apparatus comprising:

a signal converter to convert a digital signal directed to a plurality of display elements forming an array of display elements into an analog signal using a nonlinear relationship;

an interface coupled to the signal converter to provide the analog signal to at least one display element of the array of display elements;

an address generator to provide timing information for said plurality of display elements;

a signal generator operably coupled to the address generator to receive said timing information to generate a first series of pulses having a first pulse interval between a first pair of adjacent pulses and at least one second pulse interval between a second pair of adjacent pulses, said first pulse interval being different than the at least one second pulse interval; and

a driver coupled to the signal generator, said driver to use the first series of pulses to generate a second series of pulses directed to the at least one display element of the array of display elements.

26. The apparatus of claim 23, wherein the signal converter receives calibration data to determine the amplitude of the second series of pulses.

27. The apparatus of claim 26, wherein the signal converter uses the second series of pulses and the nonlinear relationship in order to adjust the magnitude of the analog signal.

28. The apparatus of claim 26, wherein the signal converter determines the magnitude of the analog signal in response to the calibration data to compensate for a perceptible degradation in the at least one display element of the array of display elements and a perceptible non-uniformity among the plurality of display elements.