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:
Jun. 22, 1999
Filed:
Nov. 18, 1997
John A Tejada, Garland, TX (US);
Douglas W Anderson, Richardson, TX (US);
Patrick A Trotta, Plano, TX (US);
Texas Instruments Incorporated, Dallas, TX (US);
Abstract
An offset reverse telephoto projection lens that is telecentric in modulator space and has an air equivalent back focal distance of at least 3.3 inches and preferably at least 4.0 inches. The lens comprising, from the image side, a first objective lens group 408 having a negative power and a second telecentric lens group having a positive power. The second telecentric lens group 410 is telecentric in object space such that the image of the aperture is focused at infinity and light converges on the object plane perpendicular to the axis of the lens. Embodiments of the lens have a back focal distance to effective focal length ratio of at least 0.86:1, preferably at least 1.2:1, more preferably at least 1.3:1, still more preferably at least 4.08:1, and most preferably 5.0:1. The embodiments described have a field of view between 14 degrees and 73 degrees, have throw ratios of 1.2:1 to 7:1, and an overall length ranging from less than 5 inches to 12.5 inches.