Hardware Reference
In-Depth Information
to handle up to 20 million keystrokes, putting them in the range of pure mechanical switches for
durability (see
Figure 15.4
). A few membrane switches are even more durable: Cherry Corporation's
G8x-series keyboards use Cherry's own 50-million-keystroke membrane switch design
(
www.cherrycorp.com
)
.
Figure 15.4. A typical membrane keyswitch used in NMB keyboards.
Membrane keyboards typically provide a firmer touch than rubber dome keyboards or the old foam-
element keyboards, and those with buckling spring designs can provide the ultimate in tactile
feedback. One interesting variation includes the line of keyboards made by KeyTronicEMS using its
center-bearing version of membrane keyswitches. Most of its keyboards feature Ergo Technology,
which has five levels of force from 35 grams to 80 grams, depending on the relative strength of the
fingers used to type various keys. As little as 35 grams of force is required for keys that are used by
the little finger, such as Q, Z, and A, and greater levels of force are required for keys used by the
other fingers (see
Figure 15.5
)
. The spacebar requires the most force: 80 grams. This compares to the
standard force level of 55 grams for all keys on normal keyboards. For more information about
keyboards with Ergo Technology, visit the KeyTronicEMS website (
www.keytronic.com
)
.
