Abstract: A membrane switch in which a membrane layer is supported in a spaced relation from at least one contact of one or more pairs of electrically conductive switch contacts. The contacts are mounted on an insulated substrate. The membrane surface adjacent the contacts has an electrically conductive bridging surface supported thereon such that depression of the membrane will bridge the contacts to complete a circuit. The membrane is mounted on the substrate and is held in a normally spaced relationship with the contacts by a plurality of projections formed on the membrane surface adjacent the substrate or one or more of the contact surfaces. The projections may be integrally formed by puncturing the membrane surface with a sharp object or projections may be formed by permanently deforming the membrane without rupturing the membrane itself. Additionally, the projections may be formed by applying individual spacer elements to the membrane surface.

Abstract: A keyboard membrane switch including the standard three layer resilient flexible diaphragm switch construction. Threshold pressure is applied to the membrane prior to engagement of the membrane contact with at least one fixed contact. This phenomenon is achieved by applying variable thicknesses of nonconductive threshold paint or glass to the substrate, flexible membrane, a first layer of threshold material or any combination thereof.

Abstract: Membrane keyboard apparatus is disclosed including an insulator having a conductive sheet thereon providing a plurality of first electrode members in the form of an array of apertures, and a plurality of second electrode members located concentrically within and spaced from the periphery of the apertures of the first electrodes to form an array of individual switching units. The height of the conductive sheet is greater than the height of the second electrode members whereby the level of the top surfaces of the plurality of first electrode members is vertically spaced above the level of the top surfaces of the second electrode members. A flexible, conductive member is disposed in a spaced relation above and adjacent to the level of the top surfaces of the pluralities of first and second electrode members. An identification member having an array of indicia corresponding to the array of individual switching units is disposed in a spaced relation above and adjacent to the flexible conductor.

Abstract: Membrane keyboard apparatus is disclosed as including an insulator having a conductive sheet thereon providing a plurality of first electrode members and a plurality of second electrode members to form an array of individual switching units. A membrane member is disposed in a spaced relation above and adjacent to the level of the top surfaces of the pluralities of first and second electrode members. The membrane member is formed of a flexible, plastic, insulative sheet member, and includes: an array of indicia corresponding to the array of individual switching units formed on the first, bottom surface of the sheet member; a background color layer formed on the bottom surface of the sheet member and over the array of indicia; a very thin, conductive layer formed on the background color layer and applied to form patterned areas for providing a conductive path between the first and second electrode members of the individual switching units selected; and height differential members formed in the membrane member.

Abstract: Membrane switch apparatus is disclosed, in its preferred form, as a keyboard including an insulator with an array of individual switching units located thereon. Each individual switching unit includes a plurality of first electrode members and a plurality of second electrode members. A flexible, nonconductive member is disposed in a spaced relation above and adjacent to the level of the top surfaces of the electrode members of the array of individual switching units. The flexible member includes conductive material located thereon in a patterned arrangement to allow sequential bridging first, of the plurality of the first electrode members and, second, of the plurality of second electrode members.

Abstract: A method of forming an insulator and electrode member is disclosed, in its preferred form, as including an insulator having a first face supporting a uniform height conductive layer. A plurality of first electrode members are formed in the conductive layer by etching away or otherwise forming an array of apertures therein. A plurality of second electrode members are simultaneously formed either by printing, screening or other similar approach forming conductive material within and laterally spaced from the array of apertures.