Improved liquid crystal structure and projecting apparatus using the same


Application Number: 00101982
Application Date: 2000.02.01
Publication Number: 1265474
Publication Date: 2000.09.06
Priority Information: 1999/3/2 US 09/260869
International: G02B27/28;G02F1/1335
Applicant(s) Name: International Business Machine Corp.
Address:
Inventor(s) Name: K. C. Hawe;Lu Minhua;A. E. Rosebruce
Patent Agency Code: 72001
Patent Agent: chen ji
Abstract A liquid crystal (LC) lightvalve comprising a twisted nematic LC layer whose molecules are aligned at the mirror backplane, thereby providing improved contrast and efficiency, and reduced visibility of post spacers in black state. The present invention is directed to an LC structure wherein the backplane is rubbed in a direction rectilinear with pixel edges. The LC layer is given the same twist rotation and birefringence as in the conventional TN lightvalve. Polarization control is maintained by illuminating the lightvalve with light whose polarization is rotated by the twist angle relative to the x, y, pixel axes, and by collecting the orthogonally polarized component of the reflected light.