Sub-pixel Compensation

• US 20180197477A1
• Filed: 03/08/2018
• Published: 07/12/2018
• Est. Priority Date: 04/28/2015
• Status: Active Grant

• Current Assignee: Microsoft Technology Licensing LLC (Microsoft Corporation)
• Original Assignee: Microsoft Technology Licensing LLC (Microsoft Corporation)
• Inventors: DIGHDE, Rajesh Manohar, ZHENG, Ying
• Granted Patent: US 10,650,750 B2
• Time in Patent Office: Days
• CPC Class Codes: G09G 2300/0443 with several sub-pixels for the same colour in a pixel, not specifically used to display gradations G09G3/364 takes precedence
• CPC Class Codes: G09G 2300/0452 Details of colour pixel setup, e.g. pixel composed of a red, a blue and two green components
• CPC Class Codes: G09G 2300/0819 used for counteracting undesired variations, e.g. feedback or autozeroing
• CPC Class Codes: G09G 2320/0233 Improving the luminance or brightness uniformity across the screen
• CPC Class Codes: G09G 2320/0242 Compensation of deficiencies in the appearance of colours
• CPC Class Codes: G09G 2320/029 by monitoring one or more pixels in the display panel, e.g. by monitoring a fixed reference pixel
• CPC Class Codes: G09G 2320/045 Compensation of drifts in the characteristics of light emitting or modulating elements
• CPC Class Codes: G09G 2320/0626 for control of overall brightness
• CPC Class Codes: G09G 2330/04 Display protection
• CPC Class Codes: G09G 3/2003 Display of colours specific for liquid crystal displays G09G3/3607
• CPC Class Codes: G09G 3/2074 using sub-pixels
• 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 3/3233 with pixel circuitry controlling the current through the light-emitting element
• CPC Class Codes: G09G 3/3258 with pixel circuitry controlling the voltage across the light-emitting element

Abstract

Sub-pixel compensation is described. In at least some implementations, a computing device includes a plurality of sub-pixels within a pixel which may generate an alternating display to approximate the display of a single sub-pixel. In other implementations, a voltage is applied to sub-pixels of a color such that a voltage across a first sub-pixel is proportional to a voltage across one or more additional sub-pixels. In other implementations, a change in a voltage drop across a sub-pixel is detected, and the change is compensated for by altering a voltage of a second sub-pixel within the pixel.

Claims

1. A device comprising:

a plurality of pixels including a first pixel, the first pixel including a first sub-pixel of a first color and a second sub-pixel of the first color; and

a driving circuit configured to;

receive an input signal representing a luminous intensity for the first color for the first pixel for a first duration; and

in response to the received input signal and during the first duration, drive the first sub-pixel for a second duration and drive the second sub-pixel for a third duration,

wherein a length of the second duration is shorter than a length of the first duration and a length of the third duration is shorter than the length of the first duration.

2. The device of claim 1, wherein:

the first pixel further includes a third sub-pixel of the first color; and

the driving circuit is further configured to, in response to the received input signal, drive the third sub-pixel simultaneously with the first sub-pixel.

3. The device of claim 1, wherein the first sub-pixel is driven during the second duration at a same luminous intensity as the second sub-pixel is driven during the third duration.

4. The device of claim 1, wherein the first sub-pixel is driven during the second duration at a different luminous intensity than the second sub-pixel is driven during the third duration.

5. The device of claim 1, wherein the length of the second duration is different than the length of the third duration.

6. The device of claim 1, wherein:

the first pixel includes a plurality of subcombinations of sub-pixels, each of the subcombinations of sub-pixels including a plurality of sub-pixels of the first color, wherein the plurality of subcombinations of sub-pixels includes a first subcombination of sub-pixels including the first sub-pixel and also includes a second subcombination of sub-pixels including the second sub-pixel;

the length of the second duration approximates the length of the first duration divided by a number of the subcombinations of sub-pixels;

the length of the third duration approximates the length of the first duration divided by a number of the subcombinations of sub-pixels; and

the driving circuit is further configured to, in response to the received input signal and during the first duration, sequentially drive each subcombination of sub-pixels.

7. The device of claim 1, wherein:

the first sub-pixel is a triangular organic light-emitting diode (OLED); and

the second sub-pixel is a triangular OLED.

8. The device of claim 1, wherein:

the first pixel is square in shape, with a first edge of the first pixel formed along a vertical line and a second edge of the first pixel formed along a horizontal line intersecting the vertical line at 90 degrees;

the plurality of pixels includes a second pixel vertically adjacent to the first pixel, square in shape, and with an edge of the second pixel formed along the vertical line; and

the plurality of pixels includes a third pixel horizontally adjacent to the first pixel, square in shape, and with an edge of the second pixel formed along the horizontal line.

9. The device of claim 1, wherein:

the first pixel includes two or more sub-pixels of the first color;

the first pixel includes one or more sub-pixels of a second color different than the first color;

the first pixel includes one or more sub-pixels of a third color different than the first color and the second color;

the first pixel includes fewer sub-pixels of the second color than sub-pixels of the first color; and

the first pixel includes fewer sub-pixels of the third color than sub-pixels of the first color.

10. The device of claim 1, wherein:

the first pixel further includes a third sub-pixel of the first color; and

the driving circuit is further configured to, while driving the first-subpixel during the first duration;

in response to the received input signal, apply a first voltage to the first sub-pixel;

output a second voltage computed based on the first voltage and a voltage drop occurring across the first sub-pixel during the application of the first voltage to the first sub-pixel; and

apply the second voltage to the third sub-pixel.

11. The device of claim 1, wherein the first pixel includes a total of six sub-pixels of the first color.

12. A device comprising:

a plurality of pixels including a first pixel, the first pixel including a first sub-pixel of a first color and a second sub-pixel of the first color; and

a driving circuit configured to;

receive an input signal voltage representing a luminous intensity for the first color for the first pixel for a first duration;

apply the input signal voltage to the first sub-pixel;

output a first voltage computed based on the input signal voltage and a voltage drop occurring across the first sub-pixel during the application of the input signal to the first sub-pixel; and

apply the first voltage to the second sub-pixel.

13. The device of claim 12, wherein the first pixel includes a third sub-pixel of the first color, and the driving circuit is further configured to:

output a second voltage computed based on the first voltage and a voltage drop occurring across the second sub-pixel during the application of the first voltage to the second sub-pixel; and

apply the second voltage to the third sub-pixel.

14. The device of claim 12, wherein the first pixel includes a third sub-pixel of the first color, and the driving circuit is configured to simultaneously apply the first voltage to the third sub-pixel and the second sub-pixel.

15. The device of claim 12, wherein:

the first pixel includes two or more sub-pixels of the first color;

the first pixel includes one or more sub-pixels of a second color different than the first color;

the first pixel includes one or more sub-pixels of a third color different than the first color and the second color;

the first pixel includes fewer sub-pixels of the second color than sub-pixels of the first color; and

the first pixel includes fewer sub-pixels of the third color than sub-pixels of the first color.

16. The device of claim 12, wherein the first voltage is calculated in proportion to the voltage drop occurring across the first sub-pixel during the application of the input signal to the first sub-pixel.

17. The device of claim 12, wherein:

the driving circuit includes a compensation circuit block configured to receive a first input voltage at a first input, receive a second input voltage at a second input, calculate a first output voltage based on the first input voltage and the second input voltage, and output the first output voltage at a second output; and

the driving circuit is configured to;

apply the input signal voltage to the first input,

during the first duration, selectively couple the second input to the first sub-pixel to receive a voltage corresponding to the voltage drop occurring across the first sub-pixel during the application of the input signal to the first sub-pixel, and

during the first duration, selectively couple the first output to the second sub-pixel to apply the first output to the second sub-pixel.

18. A method comprising:

receiving an input signal representing a luminous intensity for a first color for a first pixel for a first duration, the first pixel including a first sub-pixel of the first color and a second sub-pixel of the second color; and

in response to receiving the input signal and during the first duration, driving the first sub-pixel for a second duration and driving the second sub-pixel for a third duration, wherein a length of the second duration is shorter than a length of the first duration and a length of the third duration is shorter than the length of the first duration.

19. The method of claim 18, wherein the length of the second duration is different than the length of the third duration or the first sub-pixel is driven during the second duration at a different luminous intensity than the second sub-pixel is driven during the third duration.

20. The method of claim 18, wherein:

the first pixel includes a plurality of subcombinations of sub-pixels, each of the subcombinations of sub-pixels including a plurality of sub-pixels of the first color, wherein the plurality of subcombinations of sub-pixels includes a first subcombination of sub-pixels including the first sub-pixel and also includes a second subcombination of sub-pixels including the second sub-pixel;

the length of the second duration approximates the length of the first duration divided by a number of the subcombinations of sub-pixels;

the length of the third duration approximates the length of the first duration divided by a number of the subcombinations of sub-pixels; and

the method further comprises, in response to receiving the input signal and during the first duration, sequentially drive each subcombination of sub-pixels.