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:
Feb. 24, 1998
Filed:
Mar. 12, 1996
M Glenn Horner, West Roxbury, MA (US);
David A Waldman, Acton, MA (US);
Polaroid Corporation, Cambridge, MA (US);
Abstract
A high-efficiency holographic diffuser is provided, the holographic diffuser being comparatively thin, yet characterized by good optical density along a broad bandwidth. In particular, the high-efficiency holographic diffuser comprises a light-transmissive substrate; and a planar hologram layer, the planar hologram layer having an interference pattern holographically recorded therein, the interference pattern producing a diffuse light pattern in reflection when irradiated with light, the interference pattern being resultant of the combination of an incident wavefront and a counterpropagating wavefront substantially coherent with the incident wavefront, the incident coherent wavefront having impinged upon the planar hologram layer from a first side, the counterpropagating coherent wavefront having impinged upon the planar hologram layer from a second side opposite the first side, the incident coherent wavefront being a diffused coherent wavefront, the counterpropagating coherent wavefront also being a diffused coherent wavefront. The high-efficiency holographic diffuser can be formed by diffusing a coherent wavefront prior to its incidence on a holographic recording medium, transmitting the diffused wavefront through the holographic recording medium, then reflecting the transmitted diffused wavefront with a highly reflective optical element back through the holographic recording medium.