Automatic Beam Intensity Matching for Multiple-Beam Cathode Ray Tubes
Original Publication Date: 1989-Dec-01
Included in the Prior Art Database: 2005-Jan-29
In order for a multiple-beam cathode ray tube (MBCRT) to produce an image with a high perceived quality, the brightness of the individual beams must be matched. Failure to match the brightnesses of the beams produces bright or dark streaks in the image. In order to meet the stringent requirements of beam matching, it is necessary to adjust each of the beams to the same intensity. Intensity differences between beams come from non-uniform drifts, warm-up, aging, and variations in manufacture of the individual cathodes. Manual adjustment is difficult because when the intensity of a given beam is changed, the intensities of the beams immediately above and below appear to be altered in the sense opposite to that of the central beam.