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:
Aug. 18, 1998
Filed:
Feb. 28, 1997
Michael M Wenyon, Boston, MA (US);
Polaroid Corporation, Cambridge, MA (US);
Abstract
A projection screen is provided having a construction well-suited for effecting lateral color constancy in rear screen projection display systems. The inventive projection screen comprises a rigid light-transmissive faceplate and a homogenizing holographic transmission diffuser element proximate said faceplate. The holographic transmission diffuser element is made such that, upon illumination of an area of said diffuser element with a light beam having a wavelength of 400 nm to 700 nm, and impinging at an incident input angle of .+-.0.degree. to 30.degree. relative to normal incidence, said holographic transmission diffuser element produces in transmission a single diffuse output lobe, the diffuse output lobe produced in one area of said holographic transmission diffuser element having a relative angular intensity distribution and aspect ratio substantially identical to the relative angular intensity distribution and aspect ratio of diffuse output lobes produced in substantially all other areas of said holographic transmission diffuser element.