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:
Oct. 19, 1999
Filed:
Jun. 17, 1996
James J Appel, Rochester, NY (US);
John R Andrews, Fairport, NY (US);
Xerox Corporation, Stamford, CT (US);
Abstract
Raster scanner assemblies, and machines which use such raster scanner assemblies, which produce spots having a variable spot dimension. Raster scanner assemblies according to the present invention include an electronic subsystem which produces both image data and a spot size control signal, a laser assembly which produces a polarized laser beam having a beam with a first dimension and which is modulated in accord with the image data, a variable aperture assembly which changes the first dimension of the laser beam, a rotating polygon having a plurality of facets sweeping the laser beam in a sweep plane, and a scan lens for focusing the laser beam onto an image plane. The variable aperture assembly beneficially includes both a liquid crystal cell, which receives the laser beam and the spot size control signal, and a polarizing filter. The liquid crystal cell changes the polarization of part of the laser beam in response to the spot size control signal, while the polarizing filter passes the laser beam as a function of the beam's polarization. Beneficially, the liquid crystal cell is a twisted nematic liquid crystal cell. Preferably, the first dimension is in the cross-scan direction.