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:
Sep. 27, 2005
Filed:
Feb. 01, 2002
Takao Inoue, Kawagoe, JP;
Takao Inoue, Kawagoe, JP;
Pioneer Corporation, Tokyo, JP;
Abstract
A luminance control circuit has luminance change characteristics similar to those of a conventional lamp when a light emitting diode is used as a light source. The luminance control circuit adjusts the value of a forward current flowing in the light emitting diode in accordance with a control voltage which is obtained by smoothing a light adjustment pulse signal from an illuminance control circuit. The circuit has: a pulse adjustor for adjusting a duty factor of the light adjustment pulse signal according to characteristics of the light emitting diode; holding circuit for holding the control voltage to a predetermined value or more; and a switch for interrupting the forward current flowing in the light emitting diode by using the light adjustment pulse signal or a pulse signal after the adjustment of the duty factor, wherein at least two of these three elements are used in combination.