| 摘要 |
493,681. Optical-projection systems; projector lamps. NAAMLOOZE VENNOOTSCHAP PHILIPS' GLOEILAMPENFABRIEKEN. Feb. 24, 1938, No. 5879. Convention date, Feb. 27, 1937. [Class 97 (i)] [Also in Group XI] In an optical system comprising a source of light and a condenser, refracting surfaces are arranged in the neghbourhood of the light source so that light radiated over a given solid angle, exceeding 120‹, by the portion of the light source in or near the axis of the system, is directed on to the condenser within a smaller solid angle. The system is particularly intended for use in a kinematograph projector to enable a super-pressure mercury-vapour discharge tube to be used as the source of light. In the form shown, the condenser is a mirror 2 and the refracting surfaces comprise an annular lens 6 having a conical cavity in which the source 1 is placed. This cavity preferably communicates with another conical cavity as shown so that the lens has an axial bore. With this system, all the rays emitted over an angle c are received by the condenser, the lens forming a virtual image of the light source at the axial point 11. When a super-pressure mercury-vapour tube is used as the light source, the glass vessel, indicated in dotted lines in the Figure, which surrounds the source and acts as a receptacle for cooling liquid, is so shaped as to co-operate with the lens 6 to produce the desired effect on the light rays. Preferably, the refracting surfaces are such, and so disposed, that substantially no light falls on the axial area 12 of the mirror ; this part of the mirror can then be removed to form an aperture through which the light source and lens 6 can be passed. |
