Display Technology

Abstract

Displays are the visual interface between human and electronically generated signals. Since the advent of the cathode ray tube, many other technical solutions for displays have been investigated and optimized to specific user requirements. This article attempts to structure the complexity of display categories and is focused on technology, that is, the engineering and material science aspects of electronic display devices. The fundamental technical features of cathode ray tubes (CRTs) are outlined. The larger part of the article, however, deals with flat‐panel technologies that have been developed to overcome two of the major drawbacks of CRTs, bulkiness and high weight. Flat panel displays are distinguished as either light‐generating or (external) light‐modulating devices. In the first group, the underlying basic technologies are light generation from gas discharge, cathodoluminescence, and electroluminescence. The exploitation of gas discharge for display purposes has led to the flat, direct‐view large‐area plasma displays. Cathodoluminescence—light generation through electron impact on phosphors—is used in CRT and flat‐panel devices such as vacuum fluorescence displays and field‐emission displays. Electroluminescence is the light emission caused by the action of electronic fields in solid inorganic or organic material. In the group of light‐modulating devices, the dominating technology is based on the unique optical properties of liquid crystal material. In conjunction with additional enabling thin films (e.g., orientation layers and polarizers), these devices are used in reflective, transmissive, or transflective modes. For high performance, they rely on a matrix of active switches associated with each pixel. Other technologies in the light‐modulating group make use of a variety of microparticles, which could give way to the eventual realization of electronic paper. The article ends with a short survey on projection display technologies.