Display with aging correction circuit

• US 6,501,230 B1
• Filed: 08/27/2001
• Issued: 12/31/2002
• Est. Priority Date: 08/27/2001
• Status: Expired due to Term

• Current Assignee: Global OLED Technology LLC (LG Display Co., Ltd.)
• Original Assignee: Eastman Kodak Company
• Inventors: Feldman, Rodney D.
• Primary Examiner(s): Wong, Don
• Assistant Examiner(s): VANNUCCI, JAMES
• Application Number:
  US09/940,192
• Time in Patent Office: 491 Days
• Field of Search: 315/169.2, 315/158, 315/307, 315/308, 315/149, 315/159, 315/152, 315/312, 315/294, 315/169.3, 315/169.1, 345/55
• US Class Current: 315/169.3
• CPC Class Codes: G09G 2320/0233 Improving the luminance or brightness uniformity across the screen
• 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 2320/048 using evaluation of the usage time
• CPC Class Codes: G09G 2320/0626 for control of overall brightness
• CPC Class Codes: G09G 2360/145 the light originating from the display screen
• CPC Class Codes: G09G 3/3216 using a passive matrix
• CPC Class Codes: G09G 3/3225 using an active matrix
• CPC Class Codes: G09G 3/3275 Details of drivers for data electrodes
• CPC Class Codes: H05B 45/24 using electrical feedback from LEDs or from LED modules
• CPC Class Codes: H05B 45/60 Circuit arrangements for operating LEDs comprising organic material, e.g. for operating organic light-emitting diodes [OLED] or polymer light-emitting diodes [PLED]
• CPC Class Codes: Y02B 20/30 Semiconductor lamps, e.g. solid state lamps [SSL] light emitting diodes [LED] or organic LED [OLED]

Abstract

A display includes an electroluminescent display panel containing a light emitting material; a video interface circuit for producing an analog video signal for driving the display; an age circuit for supplying a signal representing the age of the light emitting material; an aging correction circuit responsive to the age signal for forming an analog aging correction signal, the aging correction circuit including, controller means responsive to the age signal for producing a digital correction value, and a digital to analog converter for converting the digital correction value to an analog correction signal; and a summing amplifier for summing the analog aging correction signal with the video signal.

Claims

1. A display, comprising:

a) an electroluminescent display panel containing a light emitting material;

b) a video interface circuit for producing an analog video signal for driving the display;

c) an age circuit for supplying a signal representing the age of the light emitting material;

d) an aging correction circuit responsive to the age signal for forming an analog aging correction signal, the aging correction circuit including controller means responsive to the age signal for producing a digital correction value, and a digital to analog converter for converting the digital correction value to an analog correction signal; and

e) a summing amplifier for summing the analog aging correction signal with the video signal.

2. The display claimed in claim 1, wherein the electroluminescent display is an organic light emitting diode display.

3. The display claimed in claim 1, wherein the age circuit includes a clock for measuring the amount of time the electroluminescent display has been driven.

4. The display claimed in claim 1, wherein the age circuit includes means for measuring a test pattern displayed on the electroluminescent display.

5. The display claimed in claim 1, wherein the age circuit includes means for measuring one or more electrical properties of a reference pixel located within the electroluminescent display.

6. The display claimed in claim 1, wherein the age circuit includes means for measuring the light output of a reference pixel located within the electroluminescent display.

7. The display claimed in claim 1, wherein the age circuit supplies one average age of the light emitting materials.

8. The display claimed in claim 1, wherein the age circuit supplies an average age of each light emitting material in a multicolor electroluminescent display.

9. The display claimed in claim 1, wherein the age circuit supplies an average age of the light emitting materials for subset areas of the electroluminescent display.

10. The display claimed in claim 1, wherein the age circuit supplies an average age of each light emitting material for subset areas of the electroluminescent display.

11. The display claimed in claim 1, wherein the age circuit supplies an average age of the light emitting materials for each pixel within the electroluminescent display.

12. The display claimed in claim 1, wherein the age circuit supplies the age of each light emitting material at each pixel of the electroluminescent display.

13. The display claimed in claim 1, wherein the controller means includes a controller, a memory for storing age-to-voltage correction values addressable by the controller, and a latch for holding the age-to-voltage correction values output by the memory.

14. The display claimed in claim 13, wherein the memory is volatile.

15. The display claimed in claim 13, wherein the memory is nonvolatile.

16. The display claimed in claim 15, wherein the non-volatile memory is a read-only memory (ROM).

17. The display claimed in claim 15, wherein the non-volatile memory is a FLASH memory device.

18. The display claimed in claim 15, wherein the non-volatile memory is an electrically programmable read-only memory (EPROM).

19. The display claimed in claim 15, wherein the non-volatile memory is an electrically erasable programmable read-only memory (EEPROM).

20. The display claimed in claim 13, wherein the memory and the controller are formed on a common substrate.

21. The display claimed in claim 13, wherein the latches are located within the memories.

22. The display claimed in claim 1, wherein one or more of the circuits selected from the group comprising the age circuit, the aging correction circuit and the summing amplifier is circuitry physically located on a common substrate with the electroluminescent display panel.

23. The display claimed in claim 22, wherein the circuitry located within the electroluminescent display includes the age circuit.

24. The display claimed in claim 23, wherein the age circuit supplies one average age of the light emitting materials.

25. The display claimed in claim 23, wherein the age circuit supplies an average age of each light emitting material in a multicolor electroluminescent display.

26. The display claimed in claim 23, wherein the age circuit supplies an average age of the light emitting materials for subset areas of the electroluminescent display.

27. The display claimed in claim 23, wherein the age circuit supplies an average age of each light emitting material for subset areas of the electroluminescent display.

28. The display claimed in claim 23, wherein the age circuit supplies an average age of the light emitting materials for each pixel within the electroluminescent display.

29. The display claimed in claim 23, wherein the age circuit supplies the age of each light emitting material at each pixel of the electroluminescent display.

30. The display claimed in claim 22, wherein the circuitry located within the electroluminescent display includes the summing amplifiers.

31. The display claimed in claim 1, wherein the controller means includes a controller responsive to the output of the age circuit for calculating age-to-voltage correction values, and a latch for holding the age-to-voltage correction values output by the memory.

32. The display claimed in claim 22, wherein the aging correction circuit includes a digital-to-analog converter and a digital receiver circuit for receiving digital age-to-voltage correction values, located within circuitry on a common substrate with the electroluminescent display panel.

33. The display claimed in claim 32, wherein the aging correction circuit additionally includes a latch, located within circuitry on a common substrate with the electroluminescent display panel.

34. The display claimed in claim 33, wherein the aging correction circuit located additionally includes a memory, located within circuitry on a common substrate with the electroluminescent display panel.

35. The display claimed in claim 34, wherein the aging correction circuit located additionally includes a controller, located within circuitry on a common substrate with the electroluminescent display panel.

36. The display claimed in claim, 32, wherein the digital receiver circuit is a parallel receiver.

37. The display claimed in claim 32, wherein the digital receiver circuit is a serial receiver.

38. The display claimed in claim 32, wherein the digital receiver circuit contains a demultiplexing circuit, so that a received digital age-to-voltage correction value may be routed to one of a multiplicity of video channels.