Oak Industries, Inc.

Willis A Larson

Anthony J Van Zeeland

David A Christensen

Herbert C Naylor

Joseph E Jesson

Edwina K Dulen

Philip Bierhuizen

Anthony J VanZeeland

Ray L Oughton, Jr

Steven D Vannice

A membrane switch panel has patches of low creep material attached to the membrane at portions thereof which are subject to creep. Membrane switch panels may be incorporated in keyboards wherein some of the keys may be of the alternate action type. If the alternate action keys are left in an actuated position and the keyboard is stored at a high temperature, the membrane material may be subject to creep. The present invention prevents this by including a stainless steel patch on the membrane under each alternate action type key. The stainless steel patch will not creep at elevated storage temperatures. The patch causes the membrane to be restored to its original location even after being subjected to conditions which would cause the membrane material to creep.

Membrane switch and components having means for preventing creep

A conductive adhesive for use in membrane switch and printed circuit technologies consists essentially of a resin modified copolymer of butadiene and styrene and a conductive element. The conductive element is preferably a material such as acetylene black and is more than two percent and less than 40 percent by weight of the adhesive. The conductive adhesive may be used to secure the membrane and substrate of a membrane-type switch thereby providing a conductive path between the membrane and substrate. The adhesive may also be used to attach a membrane switch tail to an associated printed circuit board or the like, again with the conductive properties of the adhesive providing a current path as well as the conventional adhesion between the two parts.

Pressure-sensitive adhesive and application thereof

This invention relates to flexible materials for use in electrical devices, such as membrane switches. The flexible component of the device is formed of paper.

Material for electrical devices having a flexible member

A flexible connector includes a flat thin insulating base and a plurality of spaced conductive paths formed thereon. There are means for providing selective interconnection between certain conductive paths on the base, which means includes a thin defined insulating patch positioned upon a selective area of the base and conductive paths. A connecting conductive path is formed on the insulating patch and extends therethrough into electrical contact with said certain conductive paths.

Flexible connector with interconnection between conductive traces

This invention relates to an arrangement for attaching discrete electrical components to a generally flat layer of sheet material. Both mechanical and electrical connections are provided by the attachment elements of the present invention. One form of the invention is directed to a membrane switch keyboard wherein one of the layers of the membrane switch has a tail extending therefrom. The tail has a free end which is adhesively secured to some portion of the keyboard. Conductive traces are formed on the tail and extend to the free end where they contact the leads of an electrical component. The component is held between the tail and the keyboard. In another aspect, which may be applied to the membrane switch keyboard just described, the invention includes a sheet material having two or more slits cut therein for each of the component's leads. The slits are cut in a portion of the sheet having conductive traces formed thereon. The leads of the component are then interlaced through the tabs created by the slits to both mechanically and electrically connect the component to the sheet.

Connector for attaching an electrical component to a flat sheet

A switching device, for example a membrane switch, having an interconnect tail for electrically connecting the switching device to a circuit board. The tail has conductive traces formed thereon, which are in circuit with the conductive elements of the switching device. The conductive traces on the tail are raised from the plane of the tail thus making the traces the most prominent part of the tail. This structure assures electrical contact with the circuit board.

Membrane switch interconnect tail and printed circuit board connection

An assembly for manufacture of a membrane switch includes a composite formed of first and second layers, one substantially thicker than the other, with the composite having a size and shape to form both outer members of a membrane switch when folded back upon itself. Metallic conductors, preferably silver, are formed on the composite prior to folding. A spacer member having spaced openings therein and extending over approximately half of the area of the composite is positioned thereupon. After the composite is folded over the spacer member, laminating heat and pressure are applied to the assembly with the result that a bond is formed between the spacer member and composite and between the layers of the composite.

Laminated membrane switch

An electrical component attachment for securing discrete components to a rigid circuit board without the use of plated-through holes. A unitary sheet member has a membrane portion and a flap portion. The membrane portion lies on one side of the circuit board. The flap portion wraps around an edge of the circuit board and is adhesively secured to the other side of the board. An electrical component is disposed between the flap portion and the board so as to be secured thereto by the flap portion. The sheet has conductive traces which contact the leads of the electrical component, providing electrical connection thereto. The sheet may have a tail onto which the traces extend for connection to external circuitry.

Switch and component attachment to flexible printed circuitry

A keyboard switch assembly includes a membrane switch matrix formed on a baseplate. There are a plurality of individual pressure applicators or keys which are mounted on the baseplate in a keyboard array. The keys are supported adjacent the membrane switch panel with each key being used to effect contact closure at a particular area of the membrane switch. Each key includes a movable plunger, a housing to support the plunger, a first coil spring biasing the plunger away from the membrane switch and a keytop affixed to the plunger. A second coil spring is seated upon the membrane switch matrix and provides the means for application of electrical contact closure pressure. Each key housing includes an enclosure which is accessible from the top of the housing. The closure is adapted to receive and retain a cam follower which controls movement of the plunger. The key housings further include a hook which can support a torsion rod. A torsion rod may be attached to an elongated keytop in an adjacent row to prevent binding of the plunger carrying the elongated keytop.

Keyboard assembly and components therefor

A membrane switch of the type actuated by bending is manufactured from a blank of flexible sheet material. An appropriate pattern of conductors is silk-screened on first and second portions of the blank. Then an insulative spacing means is silk-screened onto the first and second portions in a symmetrical pattern. Adhesive is applied to the blank. Hinges are formed along the line of symmetry of the spacing means and the second portion of the blank is folded over the first portion along these hinges to complete the switch. The adhesive holds the folded switch together with the first portion of the blank forming the switch substrate and the second portion forming the membrane.

Method of manufacture for bendable membrane switch

A method and apparatus for forming a membrane switch of the type having a flexible membrane, a substrate, first and second conductors formed on the membrane and substrate and spacing means disposed between the first and second conductors. The spacing means is applied to either the membrane or substrate in a uniform pattern of individual spacer areas. The spacer areas are applied in liquid form which is cured or allowed to dry. The pattern of spacer areas can be applied without regard to the location of the conductors. The size, spacing and thickness of the spacer areas allow contact between aligned first and second conductors when the exterior of the membrane is subjected to pressure. Thus the same pattern of spacer areas can be used with any arrangement of conductors.

Membrane switch with universal spacer means

A membrane switch construction and method for making same. A plate of relatively rigid, flat material is coated with an insulative cover and electrical conductors are formed thereon. A membrane of flexible, plastic material with conductors formed on the underside thereof overlies the plate. A non-conductive spacing means interposed between the conductors has holes in register with the conductors. The spacing means normally holds the conductors in spaced, non-contacting relation. The conductors are movable through the holes in the spacing means in response to pressure on the exterior of the membrane. One or the other or both of the sets of conductors may comprise two tiers of conductors separated by an isolation layer of non-conductive material. Holes are appropriately positioned in the isolation layer to permit access to the buried tier of conductors. Interconnect holes may also be provided in the spacing means to permit electrical connection between the conductors, thus forming a multi-layer conductive system.

Membrane switch construction and method for making same

A connecting tail for a switching device, for example a membrane switch, includes a substrate having a plurality of spaced parallel silver conductors formed thereon. To prevent migration of silver between the spaced conductors there are a plurality of parallel notches, one between adjacent silver conductors. At least a portion of the conductors are covered by an adhesive, with the notches extending into the adhesive.

Growing community of inventors

Crystal Lake, IL, United States of America

Willis A Larson