METHOD AND SYSTEM FOR COMPENSATING AGEING EFFECTS IN LIGHT EMITTING DIODE DISPLAY DEVICES

• US 20110242074A1
• Filed: 08/28/2009
• Published: 10/06/2011
• Est. Priority Date: 09/01/2008
• Status: Active Grant

• Current Assignee: Barco NV
• Original Assignee: Barco NV
• Inventors: Kimpe, Tom, Bert, Tom
• Granted Patent: US 9,058,769 B2
• Time in Patent Office: Days
• US Class Current: 345/207
• CPC Class Codes: G09G 2310/0227 related to multiple interlacing, i.e. involving more fields than just one odd field and one even field
• CPC Class Codes: G09G 2320/0242 Compensation of deficiencies in the appearance of colours
• 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 2320/041 Temperature compensation
• 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 2320/0693 Calibration of display systems
• CPC Class Codes: G09G 2360/144 the light being ambient light
• CPC Class Codes: G09G 2360/145 the light originating from the display screen
• CPC Class Codes: G09G 3/3208 organic, e.g. using organic light-emitting diodes [OLED]

Abstract

The present invention relates to a method for compensating ageing effects of pixel outputs displaying an image on a display device. The method involves displaying a first image on an active display area (6) on the display device (1) having a first plurality of pixels; displaying a second image on a sub-area (7) of the display device (1) and having a second plurality of pixels, the active display area (6) being larger than the sub-area (7) and the second image being smaller than the first image and having fewer pixels than the active display area (6); driving the pixels of the sub-area (7) with pixel values that are representative or indicative for the pixels in the activity display area (6); making optical measurements on light emitted from the sub-area (7) and generating optical measurement signals (11) therefrom, and; controlling the display of the image on the active display area (6) in accordance with the optical measurement signals (11) of the sub-area (7).

Claims

1-20. -20. (canceled)

21. A method for compensating ageing effects of pixel outputs displaying an image on a display device, comprising:

displaying a first image on an active display area on the display device having a first plurality of pixels;

displaying a second image on a sub-area of the display device and having a second plurality of pixels, the active display area being larger than the sub-area and the second image being smaller than the first image and having fewer pixels than the active display area;

driving the pixels of the sub-area with electronic signals having values that are representative or indicative for the pixels in the active display area;

making optical measurements on light emitted from the sub-area and generating optical measurement signals therefrom; and

controlling the display of the image on the active display area in accordance with the optical measurement signals of the sub-area.

22. The method according to claim 21, wherein the sub-area are divisible into different parts which are driven with a pattern based on the actual display contents, or the sub-area is divisible into different parts which are driven with a pattern based on a priori defined pixel values containing more than one driving level.

23. The method according to claim 21, wherein the optical measurements are luminance measurements.

24. The method according to claim 23, wherein the luminance measurements are carried out in sequences.

25. The method according to claim 21, wherein a step of tracking in time how a pixel of the sub-area was driven is included.

32. A control unit to that compensates for ageing effects of pixels displaying an image on a display device, the control unit comprising means to execute the steps of claim 21.

33. The control unit according to claim 32, further adapted to drive different parts of the sub-area with a pattern based on the actual display contents.

34. The control unit of claim 32 further adapted to drive different parts of the sub-area with a pattern based on a priori defined pixel values containing more than one driving level.

35. The control unit of claim 32, wherein the optical measurements are luminance measurements and the controller is adapted to carry out the luminance measurements in sequences.

36. The control unit of claim 32, further comprising means to carry out optical measurements such that light is transmitted from within the sub-area of the active display area to outside the active display area.

37. The control unit of claim 32, further adapted to track in time how a pixel of the sub-area was driven.

38. The control unit of claim 32, further adapted to carry out light output correction by luminance and/or contrast correction.

26. The system for real time correction of light output and/or colour of an image displayed on a display device, the system comprising:

a display device comprising an active display area for displaying the image, an image forming device, and an electronic driving system for driving the image forming device;

an optical sensor unit comprising an optical aperture and a light sensor having an optical axis arranged to make optical measurements on a light output from a sub-area of the active display area of the image forming device and generating optical measurement signals therefrom;

a feedback system receiving the optical measurement signals and on the basis thereof controlling the electronic driving system; and

wherein the sub-area of the active display area is adapted to show an image that is representative or indicative of the image of the complete active display area.

27. The system according to claim 26, wherein the optical measurements are luminance measurements.

28. The system according to claim 27, wherein light output correction comprises luminance and/or contrast correction.

29. The system according to claim 26, wherein the sub-area of the active display area of the image forming device is less than 1% of the area of the active display area of the image forming device.

30. The system according to claim 26, wherein the optical aperture of the optical sensor unit masks a portion of the active display area, while the light sensor does not mask any part of the active display area.

31. The system according to claim 26, wherein the optical sensor unit stands out above the active display area a distance of 5 mm or less.

39. A computer program product comprising code segments adapted for execution on any type of computing device, the code segments when executed on a computing device providing:

means for allowing display of a first image on an active display area on the display device having a first plurality of pixels;

means for allowing display of a second image on a sub-area of the active display area and having a second plurality of pixels, the active display area being larger than the sub-area and the second image being smaller than the first image and having fewer pixels than the active display area;

means for controlling driving the pixels of the sub-area according to parts of the first image; and

means for controlling the display of the image on the active display area in accordance with the optical measurement signals of the sub-area.

40. A machine readable signal storage medium storing the computer program product of claim 39.