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. 03, 2001
Filed:
Dec. 02, 1999
Applicant:
Inventor:
Paul Frederick Luther Weindorf, Novi, MI (US);
Assignee:
Attorney:
Primary Examiner:
Int. Cl.
CPC ...
G05F 1/00 ;
U.S. Cl.
CPC ...
G05F 1/00 ;
Abstract
A photopic light sensor for controlling the apparent brightness to a human observer of a fluorescent backlight uses a broad spectrum photodiode and a daylight-filtered photodiode, the latter sensing predominantly the infrared region of the broad spectrum. By properly scaling and subtracting signals from these two photodiodes, an effective response of a photopic sensor is created which may be used in a feedback loop to control the brightness of a fluorescent tube in automotive applications without the expense or package constraints incident to an infrared blocking filter of a true photopic sensor.