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 lens group and second lens group. The first magnified image (multiplier M1) formed through first lens group installed closest to image display component is also displayed on the side of image display component through second lens group , the first magnified image is amplified and projected on screen (multiplier M2, M2 > M1) by means of second lens group, and the field lens groups (23) with positive refraction force are configured between first lens group and second lens group. The F value of second lens group F2 and the F value of first lens group F1 has a relationship F2=F1/M1, for realizing a ultra-panoramic screen view angle greater than 90 DEG.