A metal contact member 10 includes a metal sheet 15, which has a plurality of streaky projecting portions extend along each other on a front surface 15A of the metal sheet 15. A rubber switch member 12 includes the metal contact member 10 and a rubber switch body 11 joined to the metal contact member 10.

A switch according to the present invention includes a base including a recessed portion on one surface of the base; a click spring having a dome shape, the click spring being provided at the recessed portion such that the bottom of the recessed portion is contacted at a dome-shaped opening side of the click spring; a cover provided to cover the recessed portion and to house the click spring at the recessed portion; and a strain detecting element attached to another surface of the base. The strain detecting element is configured to detect strain of the base, the strain occurring in accordance with a depression amount of the click spring that is depressed.

A surface layer including a base material made of a conductor and dispersed particles dispersed in the base material is formed on a surface of a fixed contact, and the dispersed particles each include a base particle that is metal oxide and a coating layer formed on an outer surface of the base particle.

This invention discloses a preparation method for precious metal switching contact components by means of plating masking, plating and etching processes. The plating masking process is performed by using a plating mask ink with or without a photo exposure machine. Plating of precious metals is performed by electroless plating or electro plating methods. Etching is carried out with etching solutions containing weak organic acids, weak inorganic acids or acidic buffering agents. Improvement of the etched surface gloss and prevention of the side etching are realized with the sulfur-contained compounds. The dust- and oil stain-resistances of the switch contacts are improved by increasing the etching depth. The switch contacts made by this invention are featured with the advantages of good reliability, good resistance to dust and oil stain, short contact bounce time, long service life, low cost of raw materials and so on.

A surface layer including a base material made of a conductor and dispersed particles dispersed in the base material is formed on a surface of a fixed contact, and the dispersed particles each include a base particle that is metal oxide and a coating layer formed on an outer surface of the base particle.