The influence of high scanning frequencies on the luminescence saturation properties of phosphors for CRT projection systems

A novel method for computing the light output on a CRT projection tube is verified and used to predict the performance of different phosphors for different scanning parameters. This model is based on measured phosphor saturation data, and can be used to predict not only the light output but also the modulation depth for a given frequency. It is shown, both experimentally and theoretically, that the use of high scanning frequencies (up to 62.5 kHz) considerably alleviates saturation problems, especially for the blue phosphor (ZnS:Ag), where a gain of more than 2 in light output has been measured. Consequently, a significant improvement in the white-D capability and resolution of CRT based projection systems can be achieved.<>