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:
Apr. 19, 1988
Filed:
Dec. 12, 1986
William D Little, Dallas, TX (US);
Other;
Abstract
In a spot projector having a reflector, a coiled filament lamp, a gate and a lens, improved light output efficiency is provided by locating the virtual filament center intermediate the reflector and the natural focus of the reflector. The gate is provided with an aperture which is substantially equal to or larger than the aperture of the reflector to accomodate the divergence of light rays produced by locating the filament to the rear of the focus point. Because the distribution of the light rays which emanate from the filament approximates a cosine distribution, and because the location of the virtual filament is behind the actual focus point, the percentage of light rays which are projected transversely through a region between the reflector and the gate is substantially reduced, and a correspondingly greater amount of filament illumination is reflected through the gate aperture, thereby producing a brighter image than would be produced by the same lamp located forward of the focus.