Projection TV receiver using three CRTs for R-G-B - monitors red and blue brightness level by photodetectors used to control amplifiers for different screen reflection levels.

摘要

A video signal from a TV receiver, video recorder or carrier (1) is presented as R-G-B components passed through switches (2,3,4) to amplifiers (5,6,7). Each colour component is therefore transmitted to a separate TV tube (8,9,10) and the images are focussed by lenses (11,12,13) onto a large screen (14). Photodetectors receive red and blue inputs back from the screen via a lens (16) and outputs represent the brightness of the components. The signals are received by a processor (17) having a memory storing valid values for the amplifier control signals. ADVANTAGE - Perfect white balance without noticeable colouration of white image spot.