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. 21, 1993
Filed:
May. 26, 1992
Nathan A Mitchell, Houston, TX (US);
Phillip J McKenzie, Houston, TX (US);
Compaq Computer Corporation, Houston, TX (US);
Abstract
A LCD backlight system which regulates the light generated by the lamp by controlling the intensity of the light using a photoresistor cell. The current provided to the lamp is controlled by a pulse width modulation (PWM) signal. The PWM signal responds to brightness adjustments by the user and to a photoresistor exposed to the light from the lamp. An operational amplifier circuit controls the PWM signal so that if the lamp is too bright, the current to the lamp is reduced, and if the lamp is too dim, the current to the lamp is increased. When the lamp brightness reaches the appropriate intensity, the output of the operational amplifier is unchanging, causing the intensity of the lamp to remain stable.
Data source: USPTO (United States Patent and Trademark Office) public patent records. Weekly synchronization. How IDiyas builds this profile