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:
Aug. 30, 1988
Filed:
Dec. 04, 1986
Gary A Dir, Fairport, NY (US);
Alain E Perregaux, Pittsford, NY (US);
Xerox Corporation, Stamford, CT (US);
Abstract
An improved transient state liquid crystal image bar having enhanced contrast with lower required driving voltage. The image bar is of the type having a nematic liquid crystal cell configured as a single array of dot shutters energizable by a single freqency voltage with crossed polarizer and analyzer. The polarizing axis of the polarizer is at 45 degrees with the liquid crystal molecules in their rest state. Thus, when all the image bar shutters are energized, it is in the non-transmission condition. For bursts of light to pass, the voltage to selected dot shutters are interrupted and reapplied. In one embodiment, the improvement is achieved by an optical compensator or thin prism placed between the polarizer and the liquid crystal cell. In another embodiment, a quarterwave plate is placed between the liquid crystal cell and the analyzer, with the analyzer being rotated about the image bar's optical axis a predetermined angle from its initial crossed position with respect to the polarizer, so that there is increased extinction of the light exiting from the liquid crystal cell, when the liquid crystal material is in its normally stable energized state.