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:
Oct. 12, 1999
Filed:
Apr. 15, 1997
Atsushi Yamanaka, Chiba, JP;
Sharp Kabushiki Kaisha, Osaka, JP;
Abstract
This invention is directed to provide a head-mounted display device (HMD) which is capable of providing a high-quality and impressive image with an improved S/N ratio through a super-wide-field-angle short-focus lens for obtaining wide-field-angle visual information. An optical device used for the HMD according to the present invention comprise: a reflecting and refracting means is made of copolymerized high-polymer material having positive and negative photoelastic coefficients against an internal stress; a first and second quarter-wave plates have refractive indexes in the direction of their thickness, which values are within the range from the minimal value and a maximal value of refractive indexes of respective quarter-wave plates; the quarter-wave plates are disposed so that their extension axes intersect each other at a right angle; first and second wideband-wave plates, each of which is prepared by bonding a half-wave plate to a quarter-wave plate at a suitable angle, are further provided; and optical elements are covered at their surfaces with anti-reflection coating or bonded to each other with optical adhesive.