Mitsumi KEK Type
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This article requires additional photographic illustration |
| Manufacturer | Mitsumi |
|---|---|
| Switch type | Tactile |
| Rated lifetime | 10 M |
| Bounce time | 10 ms |
| Tactile force | 50 g, 55 gf |
| Total travel | 2 mm, 3.8 mm |
Mitsumi KEK Type is a rubber dome over membrane switch design and OEM custom keyboard type from Mitsumi.
Description
The cross-section diagram in the datasheet appears to show one or more unlabelled objects between the dome and the membrane layer. This calls into question whether KEK Type is actually a typical three-layer membrane arrangement with pressure domes. The 1998 datasheet notes that "Mounting the chip diode on membrane (Mitsumi's own technology) has come to solve the problem of the N-key rollover which is indispensable for personal computers." No further details are given about this arrangement, and by 2000 this feature was no longer advertised.
The illustrated (ideal) force curve is similar to that of Topre switches.
Perhaps as a means of saving vertical space, the clips that retain the keycap do not share the main guide shaft but instead fit through separate holes on either side of it.
Variants
Mitsumi's 1998 catalogue cited KEK Type as having 2 mm travel and a tactile force of 50 g. In 2000, the specification was found to be 3.8 mm travel and 0.54 N (55 gf) tactile force. The cross-section diagram is identical for both variants, indicating that the later version was simply scaled up.
Keyboards
Known models:
- Mitsumi KEK-EA4AU/EA9AU (2 mm travel)
The Mitsumi-made Apple A1048 keyboard appears to use the 3.8 mm travel version but this is not confirmed.[1] Likewise, one version of the Apple USB Keyboard appears to be KEK Type.
Specifications
- KEK Type datasheet (1998)
- KEK Type datasheet (2000)
