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:
Dec. 11, 1990
Filed:
Oct. 30, 1989
DuWain K Ake, Tipp City, OH (US);
Spectra-Physics, Inc., San Jose, CA (US);
Abstract
A device for detecting and displaying the relative position of a generally horizontal reference plane of light, even when partial shading of the device occurs, produces a linear response that is independent of spot size and energy distribution. The device includes a photodetector means having first and second interdigitated photodetector elements positioned adjacent each other on the device. The first and second interdigitated photodetector elements provide first and second detection signals, respectively. A circuit means, responsive to the photodetector means, determines the relative levels of the first and second detection signals such that the position of the reference plane of light with respect to the detector device is determined. A display means, responsive to the circuit means, provides an indication of the position of the reference plane of light with respect to the detector device.