Projection optical unit, projection type color video display device, and back projection type color video display device using projection optical unit

• Main Author: HIRATA KOJI,KATO SHUJI,YATSU MASAHIKO,NAKASHIMA TSUTOMU,IKEDA HIDEHIRO
• Format: Patent
• Language: English
• Published: 06.06.2007
• 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

The invention is a projection-type color image display apparatus and rear-projection-type color image display apparatus that can greatly shorten projection distance and give consideration to dedicated high focus of apparatus. It has two lens groups of projection lens devices which comprises: first l...