Measurement of Color CRT Beam Profile and Its Application to Focus Evaluation
Toshio Asano*, Jun Mochizuki*, Kinuyo Hagimae*,
Takashi Ohta** and Nobuo Fukuhara**
*Production Engineering Research Laboratory, Hitachi, Ltd., 292 Yoshida-Machi, Tots uka-ku, Yokohama, 244 Japan
**Electron Tube & Devices Division, Hitachi, Ltd., 3300 Hayano, Mobara, Chiba, 297 Japan
A method for measuring electron beam profiles is developed with the goal of evaluating the focus of color CRT displays. To increase measurement speed, a two-dimensional sensor is used and the electron beam profile is measured from the light emission intensity of phosphor dots. The portion blocked by the shadow-mask is measured by applying a magnetic field from the glass panel side. The electron beam profile obtained by this method and the results of visual focus evaluation by character pattern are compared. Good agreement with the visual evaluation results is obtained using two types of beam cross-section areas in the high and low intensity regions.
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