A high‐luminance and high‐resolution CRT for projection HDTV display

— We have developed a 3‐in. YAG (yttrium aluminum garnet) projection CRT for an HDTV display. The densely packed phosphor screen with a multi‐layer interference filter is prepared by depositing phosphor on a YAG faceplate using a centrifugal sedimentation method. The tube's envelope is made from a glass whose expansion coefficient is well‐matched with that of YAG. The focusing characteristics of an optimally designed pre‐focusing electron gun and focusing magnet are improved for a HDTV display application. As a result, the green, red, and blue tubes reached luminances of 1.4 × 10 5 , 6.2 × 10 4 , and 8 × 10 3 cd/m 2 at a cathode current of 1.0 mA and an anode voltage of 29 kV, respectively, with a half‐intensity linewidth of 85 μm. An experimental 48‐in. rear‐projection TV set using the YAG projection tubes achieves more than 1000‐TV‐lines horizontal resolution and 300‐cd/m 2 mean white luminance.