The Challenge of the Cathode-Ray Tube

Abstract

Consultant 6.1 INTRODUCTION The cathode-ray tube (CRT) is the dominant display device for video and high-resolution applications. It has superior and more than adequate speed (bandwidth) and resolution for the presentation of time-varying pictorial information that is aesthetically satisfying to the human observer. Alphanumerics and graphics are also best displayed on the CRT. A variety of monochrome displays as well as high-quality multicolor presentations can be achieved. Such applications of the CRT extend across a broad spectrum including the following markets: consumer or entertainment, government (mili-tary and nonmilitary), industrial, and medical. The most familiar CRT display is the home television receiver. In the past thirty years, over 300 million TV sets have been sold to consumers throughout the world. The same characteristics of the CRT which made it the best choice for use with television have also enabled it to monopolize its newer application to computers. Millions of such computer displays already exist and range in use from passenger reservation displays for airlines to securities quotations for stockbrokers. The outlook is for further continued growth of the CRT. There is nothing on the horizon at the present time to replace it in applications requiring high speed and high resolution. A remarkable aspect of the dominance of the high-resolution display market by the CRT is the fact that its precursor was built by William Crookes in about 1879, over 100 year ago. The 138 life cycle of many products is only five to ten years-and here is the CRT, 100 years old with no serious challengers on the horizon. Its durability is even more amazing when one considers the fact that is is one of the few tube types that solid-state devices have failed to replace. What characteristics of the CRT have permitted it to survive so long? What special or unique advantages does it have that enable it to defy replacement by other technologies? The CRT has several unique basic attributes which make it superior to other existing technologies for high-resolution and high-speed display applications. These attributes as well as other advantageous characteristics of CRTs are: 1. The speed of response (bandwidth) and resolution of the CRT are capable of satisfying the requirements of the eye for the presentation of high-quality dynamic imagery. 2. The techniques of scanning are not only simple but versatile as well. Scanning can be raster, stroke, or random. Furthermore , they are compatible with resolutions ranging from low to very high. 3. The CRT itself has few parts and requires as little as seven connections. This number increases to eleven if the scanning means is included. 4. The CRT is versatile-one design can be used for a wide number of applications with little or no change in design. The same tube can present alphanumeric, graphic, and pictorial information. L. E. Tannas Jr., Flat-Panel Displays and CRTs