Novel method for CRT display ITC measurement

Abstract

ITC, the process that secures the deflection yoke to the Cathode Ray Tube (CRT), remains the hardest part of CRT production. There are many multiple camera vision systems used for the ITC process, with mixed results. The key problem is that single camera is dedicated to a single measurement point. In this paper, a new method of measuring geometry attributes, convergence, and purity of CRT using a single high resolution camera is reported. Critical innovations in subpixel imaging processing allows the camera to report up to 165 data points simultaneously. An advanced perspective correction algorithm made camera to CRT position non-critical. Wobble coils placed at the neck of the CRT enables high accuracy purity measurement without magnetizing the CRT. A high speed hardware platform allows near real time measurement, fast enough for interactive adjustment. Significant work on integrating the measurement report system results in a streamlined user-friendly production measurement system that can significantly shorten production time while sustaining a high quality standard.