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:
Feb. 17, 2004
Filed:
Jun. 30, 1999
Robert A. Lewis, Sunnyvale, CA (US);
Vishay Infrared Components, Inc., Santa Clara, CA (US);
Abstract
A spot detector including a light source with a lens arranged in the path of the light from the source and a lens disposed in the path of the light reflected from the medium surface. An opaque mask is provided on the far side of the receiving lens. The opaque mask is configured with at least one slit such that the size and location in two dimensions of a single spot may be detected. A photodetector generates a voltage proportional to the amount of light impinging on its photosensitive surface, which depends upon whether or not a spot is present. According to one embodiment of he present invention, a layered mask is provided wherein the optical working distance to a given mask opening is staggered by placing it on different mask substrate layers. Accordingly, different portions of the depth of field can be resolved.