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. 23, 1992
Filed:
May. 06, 1991
Charles C Hu, Saratoga, CA (US);
The Watt Stopper, Santa Clara, CA (US);
Abstract
A method and apparatus for refracting light into the field of view of an optical detector without the use of mirrors. The invention avoids an out-of-focus problem caused by the increase in the focal length with the use of mirrors which require the light to travel a greater distance than light directly impinging on the optical detector. The preferred embodiment of the present invention provides a pair of prisms which refract infrared light into the field of view of the optical detector. The prisms are mounted immediately adjacent and on either side of the optical detector so that they can refract light from outside the field of view of the optical detector and direct the light directly to the optical detector without increasing the distance traveled by the light. Each prism is preferably a thin array of prisms formed from angled grooves on a planr, transparent material.