| 摘要 |
PROBLEM TO BE SOLVED: To provide an air escape structure of a dome type switch which is thin, and is hard for dust to infiltrate therein. SOLUTION: A first fixed contact 2a and a second fixed contact 2b are set at two positions on a printed board 2. Dome type movable contacts 1 which can be deformed elastically are mounted on both fixed contacts 2a, 2b. The dome type movable contact 1 is not brought into contact with the first fixed contact 2a but an edge part 1a of the dome type movable contact 1 is brought into contact with the second fixed contact 2b under conditions such that a switch is on condition. A sheet 3 constructed of two layers, that are a base material 3a and an adhesion layer 3b, and covers the dome type movable contact 1 and the both fixed contacts 2a, 2b at two positions on the printed board 2. The adhesion layer 3b is fixed at the printed board 2 and at the top part or the neighborhood thereof of the dome type movable contact 1. In the adhesion layer 3b, an air-escape groove 3c is formed at an interval part of each position that is fitted to the each edge part 1a of the two dome type movable contacts 1 abutted on each other. One dome type movable contact 1 is pushed and reversed to thereby connect the both fixed contacts 2a, 2b, and air in the one switch is made to flow into the next switch through the air escape groove 3c.
|
