Internal schmidt CRT Available to Purchase

Projection cathode-ray tubes are now being used in a wide variety of industrial applications such as flight simulators, command and control centers and computer graphics. Many of these applications place brightness and resolution demands on the CRT and associated optics that cannot be met by consumer-grade components. Therefore, in order to optimize the price/performance for a particular application, the system designer should know the capabilities of the available industrial-grade projection CRTs and the advantages and disadvantages of each type. Two basic types of projection CRT are available: refractive and reflective. The refractive system employes a flat-faced, direct-view CRT with a refractive lens mounted to the faceplate to project the image. The reflective system is similar to a Schmidt optical system and employs a phosphor-coated target, a mirror to reflect the image and a corrector plate to remove the spherical abberations. These two designs will be compared in detail with respect to several areas: optical efficiency, thermal characteristic, chromatic dispersion, design flexibility and electronic system requirements. The brightness, resolution and thermal characteristics of an internal-Schmidt CRT design employing red (P22), blue (P22), green (P43, P53) and white P45) phosphors will be presented.