| 摘要 |
PURPOSE:To attain contactless test to a CRT to be tested by generating a pulse train sampling the afterglow of dots of the cathode ray tube at a phase where the maximum value of the afterglow is obtained always. CONSTITUTION:One dot 9 is lighted on the CRT6 to be tested and the lighting state is tested by a CCD camera 7. The test is executed by providing a sampling pulse generator 8 to sample timewise a fluorescent light of the dot at the front face of the CCD camera 7. That is, the sampling pulse generator 8 has a sectorial window, the fluorescent afterglow of the dot 9 is led to a light sensor array in the CCD camera 7 by one revolution of the window and detected as a video signal of a time corresponding to the pulse width. The video signal is generated at the phase where the maximum value of afterflow is obtained at all times to a vertical sweep signal. |
