Keypads

Abstract

A keypad with both elevated (11) and non-elevated (22) key regions, and key switches (12) 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 (41) that is rigidly held at its perimeter in a stretched condition across a switch substrate (23). The key switches include metal snap domes (12) that have an elevated central region (212) forming a downwardly facing cavity (13) defined at its edge by a ridge (214) disposed above the switch contacts (21) that electrically engages multiple switch contacts in an annular contact zone (230).

Description

technical field [0001] This invention relates to keypads and to key switches for keypads and keyboards. Background technique [0002] The miniaturization of electronic products is a basic principle of technological progress. The competitive advantage and success of a product line depends on a company's ability to offer products with increased functionality and increased portability. As technology advances, it becomes increasingly possible to miniaturize electronic circuits below the human scale, with the result that interfaces (such as display screens, keypads, cursor controls) alone determine the size of portable products. Therefore, the ergonomic quality and size of input devices (such as keypads) play an increasingly important role in the acceptance and success of a product. [0003] One type of keypad or keyboard that provides a particularly space-efficient input device is the Independent and Combined Key (IACK) keypad, which has multiple columns of effectively lower c...

AI Technical Summary

Problems solved by technology

But it is difficult to make a reliable momentary connection of more than one key switch contact at a time

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