Fujitsu FES-300
Overview
FES-300 is, or was, Fujitsu’s short-travel leaf spring switch type. Its production status is unclear, because the datasheet for FKB3000 keypads gives FES-301S as the switch, putting at least some if not all current short-travel switches under FES-301.
FES-300 switches provide high force and low travel, and are designed to be placed under a membrane cover bearing the key legends, referred to as a “sheet keyboard” (シートーキーボード). Between the contact assembly (which is soldered to a printed circuit board) and the membrane cover, is a metal plate that holds all of the switch plungers.
Design
Switch contacts can be either gold or silver. In 1980, the contact points were said to be plated with a 1 µm layer of gold.
The structure of a FES-300–based keyboard is as follows:
References
- Sheet Keyboard: Ryohei Kinoshita, Masami Ishizawa, Tetsuji Sasaki, Syutaro Tajima, Toshiaki Tanaka and Masahiko Adachi, Fujitsu, pages 947–956, November 1979
- Development and Application of Mechanical Switches: Masami Ishizawa, Hideo Nabetami and Ryohei Kinoshita, Fujitsu Scientific & Technical Journal, volume 16 no. 3 pp. 47–63, September 1980
- Fujitsu, June 1985, page 428 (Fig. 4 – Development of keyboards) and page 429 (Fig. 5 – Development of keyboard switches)