Thin film keypad and method of making same

Abstract

A thin film keypad includes a retainer sheet and a plurality of keycaps molded onto keycap attachment regions on the retainer sheet such that the keys are mechanically secured to the retainer sheet. The retainer sheet is made of a thin film material, such as polycarbonate or polyester, and each keycap attachment region includes at least a hole and/or at least one retainer anchor portion. The keycaps are molded from a plastic material, such as polycarbonate or polyester, ABS or a polycarbonate/ABS blend. The thin film material is placed in a molding tool and the plastic material is injected into a keycap mold cavity such that the plastic material flows through the holes and/or around the retainer anchor portions, thereby anchoring the keycaps to the retainer sheet.

The invention claimed is:  
     
         1 . A thin film keypad comprising: 
 a retainer sheet made of a thin film material and having a top and bottom surface, said retainer sheet including: 
 at least one hole extending through said thin film material; and  
 at least one retainer anchor portion formed from a portion of said thin film material extending upwardly from said top surface; and  
   at least one keycap molded onto a top surface of said retainer sheet and around said retainer anchor portion, said keycap including a keycap anchor portion molded through said hole in said thin film material such that said keycap anchor portion and said retainer anchor portion mechanically secure said keycap to said retainer sheet.    
     
     
         2 . The thin film keypad of  claim 1  wherein said thin film material is a plastic material.  
     
     
         3 . The thin film keypad of  claim 1  wherein said thin film material is selected from the group consisting of a polycarbonate material and a polyester material.  
     
     
         4 . The thin film keypad of  claim 1  wherein said thin film material has a thickness in a range of about 0.005 in. to 0.010 in.  
     
     
         5 . The thin film keypad of  claim 1  wherein said thin film material has a thickness of about 0.005 in.  
     
     
         6 . The thin film keypad of  claim 1  wherein said keycap is made of a plastic material.  
     
     
         7 . The thin film keypad of  claim 1  wherein said keycap is made of a material selected from the group consisting of polycarbonate, polycarbonate/ABS blend, and ABS.  
     
     
         8 . The thin film keypad of  claim 1  wherein said keypad is used in an electronic device, and said keycap anchor portion is configured to be an actuator.  
     
     
         9 . The thin film keypad of  claim 1  wherein said keycap is made of an ABS material, and wherein said thin film material is a polycarbonate material.  
     
     
         10 . The thin film keypad of  claim 1  wherein said keycap anchor portion is secured against said bottom surface of said retainer sheet.  
     
     
         11 . The thin film keypad of  claim 1  wherein said retainer anchor portion includes a flap cut out from said thin film material.  
     
     
         12 . A thin film keypad comprising: 
 a retainer sheet made of a thin film material and having a top and bottom surface, said retainer sheet including a plurality of keycap attachment regions; and    a plurality of keycaps molded onto a top surface of said retainer sheet at respective said keycap attachment regions, wherein said keycaps are molded around portions of said thin film material such that said keycaps are mechanically secured to said retainer sheet.    
     
     
         13 . The thin film keypad of  claim 12  wherein said retainer sheet includes holes extending through said thin film material at said keycap attachment regions, and wherein said portions of said thin film material around which said keycaps are molded include edges of said thin film material around said holes.  
     
     
         14 . The thin film keypad of  claim 12  wherein said portions of said thin film material around which said keycaps are molded include flaps cut out from said thin film material and extending upwardly from said top surface.  
     
     
         15 . The thin film keypad of  claim 12  wherein said thin film material is a plastic material.  
     
     
         16 . The thin film keypad of  claim 12  wherein said thin film material is selected from the group consisting of a polycarbonate material and a polyester material.  
     
     
         17 . The thin film keypad of  claim 12  wherein said thin film material has a thickness in a range of about 0.005 in. to 0.010 in.  
     
     
         18 . The thin film keypad of  claim 12  wherein said thin film material has a thickness of about 0.005 in.  
     
     
         19 . The thin film keypad of  claim 12  wherein said keycap is made of a plastic material.  
     
     
         20 . The thin film keypad of  claim 12  wherein said keycap is made of a material selected from the group consisting of polycarbonate, polycarbonate/ABS blend, and ABS.  
     
     
         21 . The thin film keypad of  claim 12  wherein said keycap is made of an ABS material, and wherein said thin film material is a polycarbonate material.  
     
     
         22 . A method of making a thin film keypad comprising: 
 forming at least one keycap attachment region on a thin film material, each said keycap attachment region including at least one molding material passage region;    placing said thin film material into a molding tool having at least one keycap mold cavity such that each said molding material passage region is located within each said keycap mold cavity, respectively;    injecting a molding material through said molding material passage region in said thin film material and into said keycap mold cavity such that at least one keycap is molded onto a top surface of said thin film material, and wherein said molding material flows around a portion of said thin film material such that said keycap is mechanically secured to said thin film material.    
     
     
         23 . The method of  claim 22  further including cutting an outline of a retainer sheet from said thin film material such that said keycap is molded onto said retainer sheet.  
     
     
         24 . The method of  claim 22  wherein said molding material is selected from the group consisting of polycarbonate, polycarbonate/ABS blend, and ABS.  
     
     
         25 . The method of  claim 22  wherein said thin film material is selected from the group consisting of a polycarbonate material and a polyester material.  
     
     
         26 . The method of  claim 22  wherein forming each said keycap attachment region includes forming at least one hole through said thin film material, and wherein said retainer sheet is placed in said molding tool with said hole positioned between said keycap mold cavity and an anchor mold cavity such that said molding material flows through each said hole and around an edge of said thin film material.  
     
     
         27 . The method of  claim 22  wherein forming said keycap attachment region includes cutting at least one flap from said thin film material to form said material passage region, and wherein said molding material flows around each said flap.  
     
     
         28 . The method of  claim 27  wherein said molding tool includes a gate for injecting said molding material, and wherein inserting said retainer sheet into said molding tool includes inserting said gate through said material passage region such that said gate moves said flap into said keycap mold cavity.  
     
     
         29 . A method of making a thin film keypad comprising: 
 forming a plurality of keycap attachment regions on a thin film material, each of said keycap attachment regions including at least one hole and at least one material passage region;    placing said thin film material into a molding tool including a female side having keycap mold cavities and a male side having anchor mold cavities, wherein said retainer sheet is positioned such that said holes are located between respective said keycap mold cavities and said anchor mold cavities and such that said material passage regions are located within respective said keycap mold cavities; and    injecting a molding material through said material passage regions in said thin film material and into said keycap mold cavities, wherein said molding material flows through said holes and into said anchor mold cavities such that keycaps are molded onto a top surface of said thin film material and are mechanically secured to said thin film material.    
     
     
         30 . The method of  claim 29  wherein said thin film material is selected from the group consisting of a polycarbonate material and a polyester material, and wherein said molding material includes ABS.  
     
     
         31 . The method of  claim 29  wherein forming said material passage regions includes cutting flaps from said thin film material, wherein said male side of said molding tool includes gates for injecting said molding material, and wherein inserting said thin film material into said molding tool includes inserting said gates through respective said material passage regions such that said gates move respective said flaps into respective said keycap mold cavities and said molding material flows around said flaps.  
     
     
         32 . The method of  claim 29  wherein forming said material passage regions includes forming formed hole portions from said thin film material, wherein said male side of said molding tool includes gates for injecting said molding material, and wherein inserting said thin film material into said molding tool includes inserting said gates through respective said material passage regions such that said molding material flows around said formed hole portions.  
     
     
         33 . The method of  claim 29  further including cutting an outline of a retainer sheet from said thin film material such that said keycaps are molded onto said retainer sheet.