Keypads and key switches

Abstract

A keypad with both elevated and non-elevated key regions, and key switches disposed beneath both types of key regions. The non-elevated key regions each provide corresponding character output based on an operation algorithm that considers activation of at least one adjacent elevated key region as well as activation of the switch below the non-elevated key region. The keypad includes a keymat that is rigidly held at its perimeter in a stretched condition across a switch substrate. The key switches include metal snap domes that have an elevated central region forming a downwardly facing cavity defined at its edge by a ridge disposed above the switch contacts that electrically engages multiple switch contacts in an annular contact zone.

1 - 34 . (canceled)  
   
   
       35 . A keypad comprising 
 a continuous web of a predominantly rigid material defining an array of apertures therethrough; and    a set of manipulable keys disposed within the apertures of the web and movable with respect to the web to operate a corresponding set of key switches;    wherein the rigid web also defines an array of key regions, at least some of which are disposed between adjacent keys, the key regions of the web comprising local elevations of the web material that overlay associated key switches that are operable by manually depressing the elevations of the web material to temporarily flex the web.    
   
   
       36 . The keypad of  claim 35  wherein adjacent key regions have an on-center distance of less than about half the width of the adult human finger.  
   
   
       37 . The keypad of  claim 35  comprising corresponding tactile feedback elements underlying each web key region and each key.  
   
   
       38 . The keypad of  claim 35  adapted to, in response to sensing a combined switch actuation including a switch underlying a key and any switch underlying a web key region immediately adjacent that key, produces an output corresponding to the key.  
   
   
       39 . The keypad of  claim 35  wherein the web is formed of a hard plastic.  
   
   
       40 . The keypad of  claim 35  wherein the web defines troughs for enhanced flexibility.  
   
   
       41 . The keypad of  claim 35  wherein the keys have a convex outer surface.  
   
   
       42 . The keypad of  claim 35  wherein the key region elevations extend higher than the keys.  
   
   
       43 . The keypad of  claim 35  wherein the keys are secured to an elastomeric sheet extending under the web.  
   
   
       44 . The keypad of  claim 35  including a printed circuit board with traces electrically connecting each of at least some switches underlying key regions with a switch underlying a corresponding one of the keys.  
   
   
       45 . An electronic device comprising 
 a housing of a relatively rigid material; and    a keypad according to  claim 35  secured to the housing by a relatively low durometer material forming a transition region between the housing material and the web.    
   
   
       46 . The electronic device of  claim 45  wherein the low durometer material comprises polyurethane.