Keypads and key switches
AssigneeDigit Wireless, LLC
InventorDavid H. Levy
Life of this patent
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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.
Claims42
A keypad comprising a matrix of key regions including
- an array of elevated key regions each providing a corresponding character output when actuated;
- and
- key regions interspersed between the elevated key regions and providing character output based at least in part on an operation algorithm that includes activation of at least one adjacent elevated key region;
- wherein
- the keypad includes corresponding, independently actuatable key switches disposed below the interspersed key regions, the operation algorithm also including actuation of the associated switches below the interspersed key regions.
A keypad comprising a keymat and a switch substrate underlying the keymat, the keymat having an exposed upper surface forming separate elevated key regions that, when pressed independent of adjacent key regions, produces an output associated with the pressed key region, the keymat also defining other key regions interspersed between adjacent elevated key regions and labeled to indicate other outputs associated with the interspersed key regions, wherein
- the keymat is rigidly held at its perimeter in a stretched condition across the switch substrate.
An electrical key switch comprising
- a printed circuit board with at least two switch contacts that are normally electrically isolated from each other;
- and
- a metal snap dome disposed above the printed circuit board, the dome having an elevated central region forming a downwardly facing cavity defined at its edge by a ridge disposed above and spaced from the switch contacts, such that when the snap dome is actuated the ridge about the central region engages the printed circuit board in an annular contact zone across the switch contacts, making electrical contact between the snap dome and the switch contacts.
Dependencies are inferred from the claim text.