PURPOSE: To decrease a drift attended with a temperature change in convergence correction and to attain high picture quality by arranging a concaved meniscus lens to a position closest to a cathode ray tube side in each projection lens group, sealing a transparent liquid refrigerant between the cathode ray tube and the lens and providing a heat pipe.
CONSTITUTION: A concaved meniscus lens having a concaved face to a transmission screen 10 side is arranged to a lens closest to cathode ray tubes 2R, 2G, 2B side among the lens group forming projection lenses 3R, 3G, 3B. Moreover, a transparent liquid refrigerant is sealed in couplers 4R, 4G, 4B and heat pipes 11-1, 11-2 are inserted above and under the transparent liquid coolant in the couplers and arranged. Thus, a heat caused in the cathode ray tubes is transmitted to the transparent liquid refrigerant and the heat pipes and when the heat reaches an equilibrium, the red, green and blue transparent liquid coolant reaches nearly the same temperature. Thus, a drift attended with the temperature change of convergence correction of the optical system for the projection picture display device is reduced while obtaining an excellent focus.
| WO/2009/105791 | NIGHT VISION GLASSES |
| JPH0664228 | [Title of the Invention] A lens provided with a light-shielding surface |
| JPWO2020137704 | Projection optics and projector equipment |
YOSHIKAWA HIROKI
MORI SHIGERU
HIRATA KOJI
NUMATA TORU
