SHADOW MASK FOR COLOR CATHODE-RAY TUBE AND ITS PRODUCTION METHOD BY MEANS OF ELECTRON BEAM PERFORATOR

摘要

PROBLEM TO BE SOLVED: To provide a production method of a shadow mask for a color cathode-ray tube that can make such holes, through with narrow electron beams can pass, that cannot be made with photo-etching method, that can carry production without contaminating the environment and further that can easily change pattern of holes for passing the electron beams. SOLUTION: Holes for passing electron beams are made by a hole making electron beams emitted from an electron-beam hole making apparatus. At this time, the hole showing a quasi-tapered profile is made by positioning the focal point of the hole making electron beams within the shadow mask material in the thickness direction.