METHOD FOR INSPECTING LUMINANCE UNEVENESS OF COLOR CATHOD-RAY TUBE

摘要

PROBLEM TO BE SOLVED: To highly accurately detect and evaluate fine uneven stripes generated at the time of exposing and forming phosphor dots on a color cathod-ray tube(CRT) independently of luminance grading. SOLUTION: A panel 5 to be inspected is illuminated by an illumination board and photographed by a telecamera 7. The picked-up image is converted into one-dimensional data by projection processing and then a secondary differential value is obtained. Detection and evaluation are executed based upon the secondary differential value and the contrast calculated from the secondary differential value. Since fine uneven stripes can be detected by this processing independently of luminance grading, the quality of a product can be improved and stabilized.