Keypad for portable telephone and manufacturing method thereof

Abstract

A keypad for a portable telephone and manufacturing method thereof is disclosed. The method comprises the steps of printing characters on a transparent, planar film; pre-forming the planar film through a pressing process such that the planar film has a predetermined shape including a plurality of depressions; punching slits in the pressed planar film around the depressions; filling liquid silicone rubber into the depressions of the pressed planar film; forming a keypad by pressing the silicon rubber in a metal mold so as to fabricate an integrated keypad in which keys are interconnected; and trimming an outer periphery of the formed keypad according to a predetermined keypad shape.

What is claimed is:  
     
         1 . A method for manufacturing a keypad, comprising the steps of: 
 printing characters on a transparent, planar film;    pre-forming the planar film through a pressing process such that the planar film has a predetermined shape including a plurality of depressions;    punching slits in the pressed planar film around the depressions;    filling liquid silicone rubber into the depressions of the pressed planar film;    forming a keypad by pressing the silicon rubber in a metal mold so as to fabricate an integrated keypad in which keys are interconnected; and    trimming an outer periphery of the formed keypad according to a predetermined keypad shape.    
     
     
         2 . The method as recited in    claim 1   , wherein the characters are printed on a rear side of the planar film.  
     
     
         3 . The method as recited in    claim 1   , wherein in the step of pre-forming the planar film, a hot press is used, the hot press being heated to a predetermined temperature such that a uniform film thickness is maintained and a distortion of the characters caused by film expansion is prevented.  
     
     
         4 . The method as recited in    claim 1   , wherein in the step of pre-forming the planar film, grooves are formed in the planar film in which light emitting devices are located.  
     
     
         5 . The method as recited in    claim 1   , wherein in the step of punching the slits, non-cutting, connecting portions are left between the slits such that the film is maintained as a single-body structure.  
     
     
         6 . A keypad for a portable telephone, comprising: 
 a printed circuit board having a plurality of contacts;    a plurality of dome switches disposed on the printed circuit board;    a plurality of keys for pushing the plurality of dome switches; and    a plurality of light emitting devices, displaced between the plurality of keys, for backlighting,    wherein grooves are formed between the plurality of keys to enable the placing of the plurality of light emitting devices thereon.    
     
     
         7 . The keypad as recited in    claim 6   , wherein slits are punched around the plurality of keys so that the keys are prevented from interfering with each other.  
     
     
         8 . The keypad as recited in    claim 7   , wherein non-cutting, connecting portions are formed between ends of the slits, so that the keys are not separated from the keypad, the connecting portions having a predetermined width.