Method of correcting nonuniformity of pixels in an OLED

• US 8,330,678 B2
• Filed: 06/15/2006
• Issued: 12/11/2012
• Est. Priority Date: 07/07/2005
• Status: Active Grant

• Current Assignee: Global OLED Technology LLC (LG Display Co., Ltd.)
• Original Assignee: Global OLED Technology LLC (LG Display Co., Ltd.)
• Inventors: Kohno, Makoto, Onomura, Kouichi, Mizukoshi, Seiichi
• Primary Examiner(s): Lao, Lun-Yi
• Assistant Examiner(s): Merkoulova, Olga
• Application Number:
  US11/424,245
• Publication Number:
  US 20070008251A1
• Time in Patent Office: 2,371 Days
• Field of Search: 345/76, 345/55, 345/36, 345/77, 345/82, 345/83, 345/207, 345/690, 345/88, 345/89, 345/90, 345/204, 315/169.3
• US Class Current: 345/76
• CPC Class Codes: G09G 2300/0842 forming a memory circuit, e.g. a dynamic memory with one capacitor
• 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 2320/0285 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 2360/147 the originated light output being determined for each pixel
• CPC Class Codes: G09G 3/3233 with pixel circuitry controlling the current through the light-emitting element
• CPC Class Codes: G09G 5/06 using colour palettes, e.g. look-up tables

Abstract

Nonuniformity in an organic EL display device is effectively detected. All display pixels of an organic EL panel are turned on and the display is photographed with a digital camera. A computer performs image processing of the photographed image to detect an area in which unevenness exists. Then, a V-I curve of each pixel in the area is measured to calculate necessary correction values. The calculated correction values are stored in a memory for use in correcting a signal input to the organic EL panel.

Claims

1. A method of correcting for pixels in an organic EL display device needing correction, in a matrix, the method comprising:

photographing an image of a display area with an imaging apparatus to specify an area in which display unevenness exists, including dividing the photographed image of the entire display area into blocks of equal size and comparing data for each pixel in each respective block and an average value of the data in all the pixels in the block, each block comprising a plurality of pixels, each block partially overlapping another block;

causing the organic EL elements of the display pixels in the specified area to emit light selectively to detect a drive current of the light emission;

calculating positions of pixels needing correction and correction data based on the detected drive current; and

storing the obtained positions of the pixels needing correction and the correction data in a memory.