| 摘要 |
PROBLEM TO BE SOLVED: To form a layer and a display part which are thin and specular without cracking even when a film is drawn by providing an inorganic material layer whose layer thickness and transmissivity to a visible light beam are specified on the reverse surface of the film. SOLUTION: The key sheet has a film 2 formed integrally on the top surface and flank of a key top main body 1 made of thermoplastic resin and on the reverse surface of the film 2, the inorganic material layer 3 is provided which is 20 to 100 nm thick and has 1 to 20% transmissivity to a visible light beam. A key sheet of this kind has a void character type display part 4 formed by vapor-depositing the inorganic material layer 3 on the reverse surface of the film 2, forming a voice character type protection layer 5 thereupon by screen printing, and etching the vapor-deposited layer in an alkali and an acid solution. Further, a colored layer 6 and a hold layer 7 are formed on the display part 4 by screen printing, the film which is deformed is put in an injection molding mold and injected after being drawn by a die which is preheated when necessary, and thermoplastic resin is injected to unite the film with the key top main body 1.
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