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

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

Abstract: A membrane keyboard is comprised of a dielectric substrate and an overlying deflectable membrane layer separated by a spacer. A plurality of contact poles are located on the dielectric substrate with an electrically conductive common contact area located on the flexible membrane. A portion of the flexible membrane is locally stiffened and, in a preferred embodiment, provided with a ridge extending away from a portion of the membrane towards the contact poles. Upon actuation of the switch, the stiffened portion of the membrane ensures simultaneity of contact between the common contact area on the membrane and the contact poles on the substrate. Preferred embodiments utilize a generally circular ridge in the deflectable membrane cooperating with interdigitated contact poles.

Abstract: Novel composite products formed by bonding a flowable elastomer, such as silicone rubber, to a transparent or translucent silicone rubber preform are described. These products have utility in the field of electromechanical devices such as an illuminated switch or key or as a transparent rubber window permitting view of an underlying display device. The bond between the preformed elastomer and the flowable elastomeric material is improved by post-curing the preform for about 4 hours at about 200.degree. C. prior to contact of the flowable material with the preform. Methods of fabrication of the novel composites are also disclosed.

Abstract: A membrane panel including at least one electrical component. The panel includes a rigid support member having substantially planar top and bottom surfaces. At least one void region, or hole, extends from the bottom surface of that support member. A flexible top member including at least one flexible layer, overlies the support member. A flexible bottom member including at least one flexible layer underlies the support member. The bottom member has its upper surface affixed to the bottom surface of the support member. Further, the bottom member includes an integral flexible tail. The bottom member includes at least one electrical component affixed to its upper surface with that component underlying and extending into an associated one of the void regions of the support member. An electrically conductive pattern is affixed to the upper surface of the bottom member and that pattern is electrically coupled to the component to permit its operation in an electrical network.