The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Dec. 15, 2015
Filed:
Aug. 26, 2004
Applicants:
David A. Fish, Haywards Heath, GB;
Jason R. Hector, Redhill, GB;
Inventors:
David A. Fish, Haywards Heath, GB;
Jason R. Hector, Redhill, GB;
Assignee:
Koninklijke Philips N.V., Eindhoven, NL;
Attorney:
Primary Examiner:
Assistant Examiner:
Int. Cl.
CPC ...
G09G 3/32 (2006.01); G09G 3/20 (2006.01);
U.S. Cl.
CPC ...
G09G 3/3233 (2013.01); G09G 3/2014 (2013.01); G09G 2300/0417 (2013.01); G09G 2300/0809 (2013.01); G09G 2300/0819 (2013.01); G09G 2300/0842 (2013.01); G09G 2310/0251 (2013.01); G09G 2310/066 (2013.01); G09G 2320/0295 (2013.01); G09G 2320/043 (2013.01); G09G 2320/045 (2013.01); G09G 2360/148 (2013.01);
Abstract
An active matrix LED display has a light-dependent device for detecting the brightness of the display element and threshold voltage measurement circuitry for measuring a threshold voltage of a pixel the drive transistor. Compensation for ageing of the display element is thus provided by an optical feedback path, and compensation for drive transistor threshold variations is provided by measurement of the threshold voltage. This provides a reliable compensation scheme for the threshold voltage variations, while also providing ageing compensation.