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Leaf springs lower keyboard profile
Thinner design yields deeper strokes
By David Bak, Editor-in-Chief, Global Design News -- Design News, March 26, 2001
Osaka, Japan — Common sense dictates that the thinner a keyboard, the shorter its key travel length. Yet Panasonic's new "Super Keyboards" reverse conventional wisdom. Though slimmer than the competition, type ESU 85/ESU 84 keyboards offer the same stroke or longer. The result: Lightweight, compact keyboards with no sacrifice in high-quality "feel."
Construction is the key. Instead of plastic scissors and a rubber cushion structure, the Super Keyboards feature three metal leaf springs. Stamped from metal coil, the leaf springs form the two halves that make up the scissors portion of the keypad (actuators 1 and 2 in the figure), plus their constraining base (actuator 3).
Once assembled, the three leaf springs mount on the membrane film and clinch to the base plate. Pressing the keycap rotates actuators 1 and 2 about their cross point or fulcrum, forcing contact with actuator 3 to activate the membrane switch.
Because the three metal leaf springs perform both actuation and contact duties, construction is simplified, assembly is faster, and the resulting keypad is stiffer. There are no rubber cushions or mold chassis as in conventional keypads built with plastic scissors. No clearance between leaf springs, which are preloaded by the keycap, lowers wobble to 0.03 mm compared to 0.16 mm for conventional scissors designs. Less wobble, furthermore, reduces operating noise.
Matsushita reports that the first targeted applications are notebook-size personal computers.
Additional Details Contact Matsushita Electronic Components Co. Ltd., 1006 Kodoma, Osaka, Japan 571-8506; or Enter 502
Other Applications
Machine control
Diagnostic equipment
Portable test and measurement
| Major Specifications | |||
|---|---|---|---|
| Item | Notebook size | Sub-notebook size | Mini-notebook size |
| Overall Height | 6.2 mm | 4.8 mm | 4.3 mm |
| Full Travel | 2.8 mm | 1.6 mm | 1.4 mm |
| Key Pitch | 19.05 mm | 16 to 18 mm | 12 to 16 mm |
| Operating Force | 0.49N | 0.49N | 0.44N |
| Operation Life | 10 million cycles minimum | 5 million cycles minimum | 5 million cycles minimum |
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