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:
Mar. 16, 1999
Filed:
Mar. 21, 1997
Hideo Taniguchi, Nara, JP;
Akihiko Taniguchi, Yamatokoriyama, JP;
Tamaki Mashiba, Nara, JP;
Masanori Mori, Ayama-gun, JP;
Sharp Kabushiki Kaisha, Osaka, JP;
Abstract
A control circuit for outputting a signal for controlling an amount of light emitted from a plurality of light emitting elements. The control circuit includes a controller or CPU, and a D/A converter outputting a signal for setting a voltage in multiple gradation in accordance with a lighting state of the light emitting element. An amplifying circuit amplifies an output of the D/A converter and outputs an amplified output as a control signal. A reference voltage generating circuit generates a reference voltage and a comparator compares the control signal with the reference voltage. The controller varies an output of the D/A converter based on the result of comparison by the comparator, to adjust the output of the D/A converter so that the control signal is equivalent to the reference voltage. Accordingly each voltage is reset in the multiple gradation to allow the light emitting element to appropriately emit light based on the adjusted output. As a result, a plurality of light emitting elements can be controlled stably without using a high precision circuit element.