Alps KKC Series
Overview
KKC series is a tactile capacitive keyboard type. With a custom PCB required, in the 1985-onwards nomenclature it is classed as a keyboard-only type.
Specifications
The specifications given in the Alps Low-Profile Keyboard Switches sample pack are unclear. The rated lifetime is unreadable in the photo, but it appears to read “1 × 10⁸cycles”. Typically, “operating force” refers to the total travel force, but here, the force curve puts that at 65 gf or higher. The force curve features a tactile drop followed by an immediate rise of the same magnitude, which is odd. The photograph of the switch does not clearly show its form; it could have an external buckling rubber sleeve (as per Key Tronic) but this is far from certain, and it may use an internal rubber dome as per two of Alps’s utility models.
| Operating force | 60 gf |
|---|---|
| Preload | ca. 18 gf |
| Total travel | 3.5 mm |
| Lifetime | 100 million cycles (uncertain) |
Models
The only known model is KFKCAA, which is a full-size keyboard model. No keyboard of this type is known to have been found.
Patents and utility models
The following utility models (“U1”) were located by a search for “スイッチ” (switch) and “キーボード” (keyboard) from Alps Electric (アルプス電気) on J-PlatPat (the Japanese Patent Platform). J-PlatPat does not provide inbound links to documents. Although earlier records exist, these are the first and only ones known to include a rubber dome or sleeve, and thus able to match up with the force curve. These utility models either cover a pre-DIN type, or they represent previous stages of the implementation of KKC.
| Document | Title | Filed | Granted | Description |
|---|---|---|---|---|
| S57-197149, U1 | 容量式スイッチ (Capacitive switch) | 1981-06-09 | 1982-12-14 | Foam pad capacitive types with internal and external domes |
| S57-197150, U1 | 容量式スイッチ (Capacitive switch) | 1981-06-09 | 1982-12-14 | Same as the above |
“zrrion” located US 4596912 “Push-button switch” (filed in February 1985 with priority to a Japanese utility model from February 1984) that appears to be much closer to how KKC appears to look. This utility model only describes the switch structure, and the switch description implies that it is foam pad conductive.
References
- Alps Low-Profile Keyboard Switches sample pack (no date specified)