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:
Mar. 28, 1989
Filed:
Nov. 18, 1986
Dean R Paulsen, Danvers, MA (US);
General Scanning, Inc., Watertown, MA (US);
Abstract
A surface scanning system defining an optical path for scanning a planar surface, in which an angularly moving scanner deflects a portion of the path, an optical element aligned with stationary portions of the optical path is driven in rectilinear sinusoidal motion for providing focus correction as the surface is scanned, and in which the sinusoidal motion of the optical element and the motion of the scanner are caused to be interdependent in frequency and phase. The sinusoidal motion of the optical element maintains accurate focus on the planar surface. In another aspect a device for moving an optical element in linear resonant motion includes a cantilevered resilient support structure arranged to permit only linear motion of the element, and means for driving the element resonantly. In another aspect apparatus for detecting the position of a beam being scanned on a surface includes oscillator means whose frequency is synchronized to the changing velocity of the scanning on the surface, and means for switching the oscillator to its maximum resolution frequency during portions of the scanning when the beam is not within an active area of the surface. In another aspect, the reading or writing on the surface occurs only at times during which the optical element is not at its maximum negative excursion.