The cathode-ray tube — Why it will not go away

Contrary to the impression created by many proponents of flat panel displays, the CRT is not the last vestige of a moribund technology. It is in fact the dominant electronic display device, and likely to remain so in the forseeable future. The reasons for the dominance are deeply-rooted in the physics of the device, and include the efficient energy conversion and simplicity of addressing inherent in a high-voltage vacuum tube display. This brief review discusses some of the significant new developments in the CRT field. These cover several aspects of tube design and fabrication, such as the flat CRT, the use of fibre optics and the various approaches to multicolour displays. The unequalled versatility of the CRT is due in no small part to the range of phosphor characteristics now available, giving control of display colour, persistence, line-width etc. Recent trends in phosphor research are outlined, including novel composite phosphor materials resulting from developments in powder-handling technology, narrow-band phosphors for contrast enhancement, phosphors for low-voltage displays and screens made from transparent thin phosphor films. In reality the CRT is constantly evolving to meet the requirements of the display user, and so far there is no evidence to suggest that it is the CRT which faces extinction in this evolutionary process.