Patent ID: 7182907
Filing Date: 2007-02-27
Classification: H01H

Abstract:
1. A method for manufacturing a key top member for a push button switch structure including key top elements, said method comprising the steps of: providing a thermoplastic resin sheet having first portions, second portions, and a plurality of display sections printed on said first portions thereof so as to conform to outer configurations of said key top elements, wherein said first portions are adapted to constitute top surfaces of said projections corresponding to said display sections; heating said second portions of said thermoplastic resin sheet so as to be softened using a heating die; thereafter, introducing the heated thermoplastic resin sheet into a forming mold provided with protrusions for forming said projections so as to locate said first portions at a level substantially identical to that of a top surface of each of said protrusions of said forming mold; shaping within said forming mold the heated thermoplastic resin sheet to provide said projections so as to form said thermoplastic resin sheet with said projections having configurations conforming to outer configurations of said key top elements; and securely arranging filler members made of photo-setting resin in said projections to constitute said key top elements in cooperation with said projections, wherein said shaping of the heated thermoplastic resin sheet includes stretching the heated second portions of said thermoplastic resin sheet without substantially stretching said first portions to thereby prevent deformation of said display sections previously printed and misregistration of printing thereon.