Dynamic controller for active-matrix displays

• US 20020175885A1
• Filed: 03/26/2001
• Published: 11/28/2002
• Est. Priority Date: 03/26/2001
• Status: Active Grant

• Current Assignee: Global OLED Technology LLC (LG Display Co., Ltd.)
• Original Assignee: Eastman Kodak Company
• Inventors: Cok, Ronald S.
• Granted Patent: US 7,164,417 B2
• Time in Patent Office: Days
• US Class Current: 345/82
• CPC Class Codes: G09G 2300/08 Active matrix structure, i.e. with use of active elements, inclusive of non-linear two terminal elements, in the pixels together with light emitting or modulating elements
• CPC Class Codes: G09G 2320/0285 using tables for spatial correction of display data
• 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 2320/043 Preventing or counteracting the effects of ageing
• CPC Class Codes: G09G 2320/0626 for control of overall brightness
• CPC Class Codes: G09G 2330/10 Dealing with defective pixels
• CPC Class Codes: G09G 2360/141 the light conveying information used for selecting or modulating the light emitting or modulating element
• CPC Class Codes: G09G 2360/145 the light originating from the display screen
• CPC Class Codes: G09G 3/20 for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix no fixed position being assigned to or needed to be assigned to the individual characters or partial characters
• CPC Class Codes: G09G 3/32 semiconductive, e.g. using light-emitting diodes [LED]

Abstract

A dynamic controller for a light emitting active-matrix display, the display being responsive to code values for producing a light output, including: photosensor located on the display for sensing the light output from the display and generating a feedback signal representative thereof; a feedback signal converter for converting the feedback signal to a converted feedback signal having the same form as the code value; a code-value corrector including a memory responsive to a code value for producing a corrected code value; and an update calculator responsive to the converted feedback signal, the code value and the corrected code value to update the memory to minimize the difference between the converted feedback signal and the code value.

Claims

1. A dynamic controller for a light emitting active-matrix display, the display being responsive to code values for producing a light output, comprising:

a) a photosensor located on the display for sensing the light output from the display and generating a feedback signal representative thereof;

b) a feedback signal converter for converting the feedback signal to a converted feedback signal having the same form as the code value,

c) a code-value corrector including a memory responsive to a code value for producing a corrected code value; and

d) an update calculator responsive to the converted feedback signal, the code value and the corrected code value to update the memory to minimize the difference between the converted feedback signal and the code value.

2. The controller claimed in claim 1, further comprising an intermediate memory for receiving and storing corrected data signals from the data signal corrector and supplying the corrected data signals to the display.

3. The controller claimed in claim 1, further comprising an intermediate memory for receiving and storing converted feedback signals from the feedback signal converter and supplying the converted feedback signals to the correction signal calculator.

4. The controller claimed in claim 1, wherein the feedback signal is an analog current signal and the converted feedback signal is a digital code value.

5. The controller claimed in claim 1, wherein the code values are supplied to the display device as analog signals, and further comprising a digital to analog converter for converting the digital signals to analog signals prior to applying the code value signals to the display device.

6. The controller claimed in claim 1, wherein the code values are supplied to the display as digital signals.

7. The controller claimed in claim 1, wherein the active-matrix display includes display pixels and a photosensor for each display pixel.

8. The controller claimed in claim 1, wherein the active-matrix display includes representative pixels and a photosensor for each representative pixel.

9. The controller claimed in claim 8, further comprising means for sending every code value to the representative pixel and producing a corrected code value for every code value.

10. The controller claimed in claim 1, wherein the display and the dynamic controller are partitioned into multiple units.

11. The controller claimed in claim 1, wherein the display device is a color display device and the dynamic controller includes a representative pixel and a photosensor for each color.

12. The controller claimed in claim 11, including a separate feedback signal converter, code-value corrector, and update calculator for each color.

13. The controller claimed in claim 1, wherein the display is a color display and the code-value corrector includes means for performing color transformations on the code values.

14. The controller claimed in claim 1, further comprising means for compensating the converted feedback signal for a global display attribute.

15. The controller claimed in claim 14, wherein the global display attribute is ambient illumination.

16. The controller claimed in claim 1, wherein the feedback signal converter includes circuitry to compensate for pixel-specific display attributes.

17. The controller claimed in claim 1, wherein the feedback signal converter includes circuitry to compensate for position-specific display attributes.

18. The controller claimed in claim 1, including means for updating the memory upon start-up.

19. The controller claimed in claim 1, wherein the controller and the display device are integrated on a common substrate.