Abstract: A screen assembly for use in projection type color television system includes a first layer of acrylic resin having a first surface formed with Fresnel lens and its second surface integrally formed with a second layer acrylic resin containing pigment for forming a diffuser.

Abstract: A variable capacitance semiconductor device is provided wherein a plurality of capacitance elements each having a fixed capacitance value are coupled in parallel with each other and at least two insulated gate field effect transistors are provided for each of the plurality of capacitance elements, whereby the total length of the insulated gate field effect transistors is made as long as possible and accordingly the resistance across the transistors when these are turned on becomes small. Each capacitance element may comprise a single semiconductor substrate of one conductivity type, an opposite conductivity type region formed on one surface of the substrate, an insulating layer formed on the opposite conductivity type region and an electrode formed on the insulating layer. The above described at least two insulated gate field effect transistors are formed such that the above described substrate is shared.

Abstract: A projection type color television system of the present disclosure comprises three cathode ray tubes each adapted to produce one of three different primary color light beams, a projecting screen and three lens assemblies positioned between the projecting screen and respective cathode ray tubes. The glass faceplate or phosphor screen of the three cathode ray tubes are positioned on an imaginary plane which is in parallel relation to the projecting screen, and principle planes of the three lens assemblies are also position in an another imaginary plane which is in parallel relation to the projecting screen, so that the projected image from any one of cathode ray tubes geometrically overlaps with another projected image from another cathode ray tube. Each cathode ray tube is coupled with a brightness correction circuit for correcting the brightness of the projected image on the projecting screen to be uniform.