Shin-etsu Polymer Co., Ltd.

Kinji Kuroiwa

Mikio Kiyosawa

Sadao Nakano

A method for forming a pad character in a key top for a push button switch and a method for manufacturing a cover member for a push button switch capable of permitting a push button switch to be manually operated in a manner comfortable to fingers over an extended period of time while preventing wearing of an indication section and simplifying the manufacturing of the cover member for the push button switch. A pigment particle is coated with a volatilization layer formed of resin blended with an electromagnetic wave absorbing powder to prepare a laser-sensitive color developing agent, which agent is then added to a thermosetting resin or elastomer material to prepare a composition. Each of key tops is formed of the composition, followed by irradiation of a laser beam on each of the key tops to form a character-like or figure-like indication section in the key top.

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Saitama, Japan

Kinji Kuroiwa