| 摘要 |
PURPOSE:To prevent deterioration of color purity due to color slippage or the like of a picture while reducing doming of a shadow mask by forming a film layer having a low thermal expansion coefficient and the low heat conductivity on the main face on the side of an electron gun of a shadow mask. CONSTITUTION:Lead borate glass 11 dissolved in an acetic acid butyl alcohol solution, in which several % of nitrocellulose is dissolved, is applied to the side of an electron gun of a shadow mask 5. Next, an organic film 12 is further formed on said film layer for preventing glass particles from falling down. The shadow mask 5 formed in this way is made to pass a heat treatment furnace, then a glassified lead borate glass layer can be formed on the side of the electron gun of the shadow mask 5. Further, the organic film 12 disappears by heating. The heat generated by lead borate glass, which an electron beam hits, reduces its amount to be conducted to the mask due to the small thermal conductivity of the lead borate glass thus being able to effectively check temperature rise of the shadow mask. |
