A silver-coated composite material for movable contact 100 includes a base material 110 composed of an alloy whose main component is iron or nickel, an under layer 120 which is formed at least on part of the surface of the base material and which is composed of any one of nickel, cobalt, nickel alloy and cobalt alloy, an intermediate layer 130 which is formed on the under layer and which is composed of copper or copper alloy and an outermost layer 140 which is formed on the intermediate layer and which is composed of silver or silver alloy, and is characterized in that a total thickness of the under layer 120 and the intermediate layer 130 falls within a range more than 0.025 µm and less than 0.20 µm.

There is disclosed a push button switch which comprises rubber contacts each including a contact portion (311), a flared portion (312) formed integrally with the periphery of the contact portion (311), and a ring-shaped portion (313) formed integrally with a lower end of the flared portion (312) and disposed on a printed board (1) wherein the following relation is satisfied: $\text{0.3 ≦ d / a ≦ 0.7, 4 ≦ d / t ≦ 6, 1.0 ≦ d / h ≦ 1.4, 150° ≦ ϑ ≦ 165°, 1.5 ≦ h ≦ 3}$ where t is the thickness of the flared portion (312), d is the length of the flared portion (312), a is an inner diameter of the ring-shaped portion (313), ϑ is an opening angle formed by an inner side surface of the flared portion (312) and a top surface of the printed board (1), and h is the distance between a bottom surface of a conductor (32) and the top surface of the printed board (1). Only the rubber contacts provide a sufficient operational load and a clear click feeling required for a vehicle-mounted switch without using the conventional spring and sliding element. This accomplishes an inexpensive, small-sized vehicle-mounted push button switch.

Disclosed is a keypad for use with compact and portable cellular telephone systems in which each key is backlit. A partially translucent overlay layer (10) of flexible material includes a raised key (12). Under the key (12), in a preferred embodiment, is an actuation layer (14), which, during operation, is depressed downward by the key (12). Below the actuation layer (14), is a tactile feedback layer (20) including a dome (30) for each key (12), in which, after being depressed to a predetermined degree, the dome (30) inverts causing a conductor (44) located below the dome (30) to short conductive traces (28) on a substrate (24) upon which the keypad is mounted. In a preferred embodiment, the keys are backlit by a light source (40) extending through the substrate (24) upon which the keypad is mounted. The tactile feedback layer includes a structure for reducing pressure on the light source when the tactile layer (20) is in the inverted condition, resulting in a thinner keypad with a brighter backlit key and a longer lift light source.

L'invention concerne le petit appareillage électrique notamment pour équipements électroniques.

Le commutateur électrique à bouton-poussoir (2) comporte une membrane en élastomère de rappel cloquante (13) qui porte un contact électrique mobile (21) et qui est interposée entre le bouton-poussoir et le corps du commutateur (1) muni d'un contact fixe correspondant. Il comporte, en outre, au moins une membrane cloquante supplémentaire de rappel (14, 15), sans fonction électrique, interposée aussi entre le bouton-poussoir et le corps du commutateur.

L'invention est applicable aux commutateurs électriques à bouton-poussoir, monostables ou bi­stables, utilisables, notamment dans l'appareillage électronique.