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. 29, 1987
Filed:
Aug. 01, 1986
Applicant:
Inventor:
Roy D Hoffer, Lancaster, PA (US);
Assignee:
Armstrong World Industries, Inc., Lancaster, PA (US);
Attorney:
Primary Examiner:
Int. Cl.
CPC ...
H05B / ;
U.S. Cl.
CPC ...
315158 ; 315151 ; 315156 ; 315D / ; 315D / ;
Abstract
A room lighting control system which controls the electrical power supplied to the artificial lighting in an area based on the ambient light available. A photocell controlled digital lamp dimming circuit with particularly high stability for time and temperature is combined with a slow response time to avoid short term adjustments. A digital counter is used to determine a large number of steps over the adjustment range and the driving clock operates at a very low frequency, so that changes in light level take a relatively long time, and it takes an exceptionally long time to span the entire adjustment range.