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:
Feb. 17, 2004
Filed:
Feb. 10, 2003
John M. Shannon, Whyte Leafe, GB;
Alan G. Knapp, Crawley, GB;
Koninklijke Philips Electronics N.V., Eindhoven, NL;
Abstract
An active matrix electroluminescent display device in which the drive current through an electroluminescent display element ( ) in each pixel ( ) in a drive period is controlled by a driving device ( ) based on a drive signal applied during a preceding address period and stored as a voltage on an associated storage capacitor ( ). In order to counteract the effects of display element ageing, through which the light output for a given drive signal level diminishes over time, the pixel includes electro-optic discharging means ( ) coupled to the storage capacitor and responsive to the display element's light output to leak stored charge and to control the integrated light output of the display element in the drive period. For improved control, the discharging means is arranged to rapidly discharge the capacitor at a controlled point in the drive period, upon the drive of the display element falling to a low level. A photoresponsive transistor can conveniently be utilised for this purpose.