High-brightness and high-resolution projection CRT

摘要

A new 3-in. projection CRT that YAG(Y$-3$/Al$-5$/O$-12$/) single crystal is used for the substrate of the phosphor screen has been developed. This phosphor screen has a number of unusual properties. The substrate has a very high coefficient of thermal conductivity and a high transparency. To obtain matched sealing, a low melting point solder has been developed to combine the substrate with the glass envelope. An electrostatic-electromagnetic focusing electron gun with large emitting current and high-resolution is developed. As a result, beam spot diameters of 0.065 mm and 0.080 mm are achieved at cathode currents of 0.5 and 1 mA, respectively. The focusing luminance is 1.4 $MUL 10$+5$/ cd/m$+2$/ for green phosphor-screen at cathode current of 1 mA and the anode voltage of 29 KV. The focusing luminances of red phosphor-screen and blue phosphor screen are 6.4 $MUL 10$+4$/ cd/m$+2$/ and 8 $MUL 10$+3$/ cd/m$+2$/ at cathode current of 1 mA, respectively. Thus, the projection TV set using these projection tubes has achieved high-brightness, high-resolution and high-contrast image display.