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:
Jul. 09, 1996
Filed:
Feb. 01, 1994
Ronald G Hegg, Vista, CA (US);
Hughes Training, Inc., Los Angeles, CA (US);
Abstract
An optical arrangement that provides a telecentric helmet mounted display optical system. The optical arrangement comprises an image source including a faceplate wedge attached to a liquid crystal display, such as an active matrix liquid crystal display, for example, that is illuminated with collimated fight. The output image is used as a light source for an off-axis or on-axis reflector used to produce an output image. The faceplate wedge corrects the anamorphic distortion exhibited in the off-axis reflector and directs the light energy into the off-axis entrance pupil of the reflector to maintain high uniformity over the exit pupil without sacrificing brightness. More particularly, the present invention comprises the input light source, and the liquid crystal display that is illuminated with collimated light from the light source. The faceplate wedge is optically coupled to the liquid crystal display, and the reflector is optically coupled to the faceplate wedge for producing an output image. The faceplate wedge corrects for anamorphic distortion exhibited in the reflector and directs light energy into an off-axis entrance pupil to maintain high uniformity over the exit pupil without sacrificing brightness. The reflector may comprise an off-axis or on-axis portion of a parabolic reflector. The optical arrangement may further comprise a collimating lens disposed between the liquid crystal display and the input light source. The collimating lens may comprise a Fresnel lens. In an off-axis version, the optical arrangement may further comprise first and second planar reflectors disposed between the input light source and the collimating lens, and a negative lens optically coupled to an output surface of the faceplate wedge. In an on-axis version, the optical arrangement may further comprise a beamsplitter optically coupled between the faceplate wedge and the reflector.