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Typical Membrane Switch Design and Construction

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Membrane Switch Manufacturing and Supply

Typical Membrane Switch Design and Construction

Typical membrane switches incorporates the following layered components:

  • Graphic presentation layer
  • Graphic adhesive layer
  • Circuit or PCB layer
  • Adhesive separator layer
  • Optional second circuit or PCB layer
  • Adhesive layer

Description of each Membrane Switch Layer:

The Graphic presentation layer of the membrane switch is a graphic overlay. The configuration is dependant on the function of the device. The graphic presentation layer is typically a printed material, such as polyester or silicone rubber.

Graphic adhesive layer facilitates the assembly of the graphic presentation layer to the circuit layer which receives the mechanical pressure applied to the membrane switch domes. This layer is typically made from polyester type material with adhesive on both sides, and is normally designed a few thousands of a inch smaller than the dome height. This is done to allow a small preload on the dome to facilitate a tactile feel on the selection pads. Sometimes, as dictated by the membrane switch application, this layer will include venting of the domes to allow the trapped air within the dome to escape during actuation / pressing of the pad-dome.

The Circuit or PCB layer includes the membrane switch electronics, as well as the dome feature. The circuit layer includes the "Interdigitated switch pole pairs for each button-dome combination of the membrane switch. .

Adhesive separator layer is an optional layer to facilitate an additional circuitry required for some Membrane switches applications. This layer will accommodate interconnection to the dome circuit layer. This layer will have adhesive on both sides for assembly.

Optional second circuit or PCB layer incorporates additional circuitry required by the membrane switch application. This layer typically includes the necessary flex cable or interface pins to integrate the membrane switch.

Adhesive layer on the mounting surface of the membrane switch is provided as a design option to mount the membrane switch to the target installation. Membrane switches may be designed into a plastic injection molded enclosure or case with application mounting feet as well.

Note:

Metal domes used on membrane switches can be designed with a wide range of stainless steel shapes and degree of tactile responsiveness. Typical applications may have 4 legs and be 12 mm square with trip or snap forces between 200, to 500 grams.

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