Semi-Automated Correction for Crt and Deflection Yoke Distortion
Original Publication Date: 1989-May-01
Included in the Prior Art Database: 2005-Jan-28
Each CRT/yoke combination requires unique magnetic corrections for centering, N-S and E-W pincushion correction, and beam distortion. These unique magnetic correction signatures are obtained with the front-of-screen fixture and hardware shown in Fig. 1. Yoke modifications are shown in Fig. 2 to accommodate two flexible vinyl rods which have been loaded with neodymium/iron/boron magnetic filler. (Image Omitted) Under program control, analog outputs from D/A converters first supply current waveforms to electromagnets temporarily placed around rear of yoke (replacing the centering rings). Signals from front- of-screen sensors serve in a closed-loop servo system to obtain centering. This information is used to "write" a magnetic pattern on one of the vinyl/magnetic filler rods which is then installed on the rear of the yoke.