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:
Jul. 14, 2020
Filed:
Sep. 22, 2017
Koninklijke Philips N.v., Eindhoven, NL;
Mark Thomas Johnson, Arendonk, NL;
David Andrew Fish, Worthing, GB;
Koninklijke Philips N.V., Eindhoven, NL;
Abstract
An actuator device comprises an active matrix array of rows and columns of electroactive polymer actuators, each electroactive polymer actuator having a switching circuit. The switching circuit has a drive transistor and a capacitor arrangement. The capacitor arrangement is charged to a voltage derived from a drive voltage for the electroactive polymer actuator combined with a voltage derived from the drive transistor threshold voltage. During this programming of the capacitor arrangement, the EAP actuator is isolated from any current flowing. The switching circuit enables compensation for age-related changes in the threshold voltage. Thus, a low performance (i.e. with poor threshold voltage stability) transistor may be used, with measurement of the threshold voltage of the current-providing TFT once per frame time (or once per multiple frame times) to compensate for the aging effect.