OPTICAL UNIT, PROJECTION TYPE VIDEO DISPLAY DEVICE AND POLARIZING PLATE USED THEREIN

• Main Authors: HODEN KAZUO, SHIAKI TAKUYA, YAMAGUCHI EIJI
• Format: Patent
• Language: English
• Published: 02.09.2004
• Edition: 7
• Subjects: ACCESSORIES THEREFOR; APPARATUS OR ARRANGEMENTS EMPLOYING ANALOGOUS TECHNIQUES USINGWAVES OTHER THAN OPTICAL WAVES; APPARATUS OR ARRANGEMENTS FOR TAKING PHOTOGRAPHS OR FORPROJECTING OR VIEWING THEM; CINEMATOGRAPHY; ELECTRIC COMMUNICATION TECHNIQUE; ELECTRICITY; ELECTROGRAPHY; HOLOGRAPHY; OPTICAL ELEMENTS, SYSTEMS, OR APPARATUS; OPTICS; PHOTOGRAPHY; PHYSICS; PICTORIAL COMMUNICATION, e.g. TELEVISION

PROBLEM TO BE SOLVED: To secure the brightness and the contrast of a video together with the heat radiation property of a polarizing plate in a projection type video display device. SOLUTION: The polarizing plate arranged on the light incident side of a video display element is constituted so that a polarizing element is held on a sapphire base plate and an angle formed by the optical axis of the sapphire base plate with the absorbing axis of the polarizing element is within the range of 90°±6° (excepting the range of ±2°) or 0°±6° (excepting the range of ±2°), and constituted so that the polarizing element is arranged on the video display element side and the sapphire base plate is arranged on a light source side. The thickness of the sapphire base plate is set to about 0.3×10-3to 1.0×10-3m. COPYRIGHT: (C)2004,JPO&NCIPI