Method of reducing the temperature difference between upper and lower portions of a lamp bulb, optical unit, projection type display apparatus and projection television apparatus

• Main Authors: HASEGAWA, HIROSHI, OHMURA, YUKIO, UNO, NAHOKO
• Format: Patent
• Language: Chinese; English
• Published: 16.05.2006
• 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; BASIC ELECTRIC ELEMENTS; BLASTING; CINEMATOGRAPHY; ELECTRIC COMMUNICATION TECHNIQUE; ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS; ELECTRICITY; ELECTROGRAPHY; FUNCTIONAL FEATURES OR DETAILS OF LIGHTING DEVICES OR SYSTEMSTHEREOF; HEATING; HOLOGRAPHY; LIGHTING; MECHANICAL ENGINEERING; PHOTOGRAPHY; PHYSICS; PICTORIAL COMMUNICATION, e.g. TELEVISION; STRUCTURAL COMBINATIONS OF LIGHTING DEVICES WITH OTHERARTICLES, NOT OTHERWISE PROVIDED FOR; WEAPONS

A method and apparatus is disclosed which minimizes the temperature difference between upper and lower portions of a lamp bulb in an optical unit. A UV-IR cut filter is disposed in a downwardly inclined relationship such that an upper portion thereof is nearer to a discharge lamp than a lower portion thereof so that infrared rays and ultraviolet rays included in light emitted from a lamp bulb and reflected in a forward direction from an upper portion of a reflecting face are reflected toward a lower portion of the reflecting face. As the reflected light from the UV-IR cut filter is illuminated on the lower portion of the reflecting face, the temperature difference between upper and lower portions of the lamp bulb is reduced.