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.

Date of Patent:
Jul. 03, 2001

Filed:

May. 12, 1999
Applicant:
Inventors:

Yutaka Koshikawa, Hachioji, JP;

Makoto Tomioka, Hachioji, JP;

Takayuki Suzuki, Hachioji, JP;

Akira Hasegawa, Musashino, JP;

Assignee:
Attorney:
Primary Examiner:
Int. Cl.
CPC ...
F21V 8/00 ;
U.S. Cl.
CPC ...
F21V 8/00 ;
Abstract

An apparatus and method is disclosed which stabilizes the light incident a light guide end over a guaranteed operating lifetime of a lamp used to illuminate the light guide end. The apparatus and method minimize variation in illumination incident a light guide end without, for example, controlling the electrical input to the lamp. The invention is especially effective for light guides having a narrow outer diameter, and compensates not only for movement of a region of maximum luminosity, as occurs in lamps where the cathode is partially consumed during operation of the lamp, but also for the lamp luminosity decreasing with age.


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