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. 23, 1979
Filed:
Aug. 10, 1977
John E Bigelow, Clifton Park, NY (US);
Donald E Castleberry, Schenectady, NY (US);
General Electric Company, Schenectady, NY (US);
Abstract
The molecules in a twisted nematic liquid crystal are, in general, skewed relative to the optical axis of the cell (the perpendicular to the plane surfaces defining the boundaries of the crystal cell), and their birefringent effect on plane polarized light varies asymmetrically for such light making varying angles with the optical axis of the cell. When the cell is positioned between crossed polarizers and the cell is energized so that light is supposed to be completely extinguished, some rays are nevertheless transmitted so that the transmitted intensities at different viewing angles vary. To avoid this resulting variation of intensity with viewing angle, the cell is illuminated from behind with collimated light (i.e., all rays parallel to the optical axis of the cell) so that all rays 'see' the average molecular director in the same way; a solid catadroptric element is utilized to both collimate the light and achieve essentially constant luminous flux intensity upon the display. To restore a reasonably wide angle of view, a diffuser is positioned in front of the display. The invention may be used with any type of display device which has a transmission characteristic which varies with the angle of rays passing therethrough.