MEMBRANE SWITCH & PRINTED GRAPHIC OVERLAY TERMINOLOGY

ABRASION RESISTANCE

The degree as to which a membrane switch's graphic overlay is able to withstand surface-wear.

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ACTUATION FORCE

The pressure necessary for actuating the circuit of a membrane switch or rubber keypad.

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ADHESION

The molecular attraction of one material to another. The strength of the bond is determined by the surface energy in each material.

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BACKING / MOUNTING ADHESIVE

An adhesive applied to the back of a membrane switch for mounting purposes.

 

BREAKDOWN VOLTAGE

The minimum voltage at which the insulation between two conductors begins to fail.

 

CARBON GRAPHITE INKS

The type of ink that consists of prepared suspensions of carbon black and is frequently printed over silver circuitry to diminish the potential of migration of silver. These are also used for lessening costs when the conductivity of a metal base system is not necessary.

 

CONDUCTIVITY

A material’s ability to allow electrons to flow.

 

CROSS-OVER

A conductor intersection where the traces are kept separated and insulated by dielectric material insulator.

 

DEAD FRONT PRINT

A cosmetic feature of a graphic overlay in which a button is only visible when backlit.

 

DIELECTRIC

An insulating or non-conducting medium.

 

DIELECTRIC INKS

Used for printing protective patterns on conductive printing to isolate selected regions from electrical contact with other conductors. This is used for cross-overs and tail insulation on membrane switches.

 

DOME COVER

An adhesive layer made to hold metal domes in the key-switch.

 

EL LAMP

A slender device that illuminates large areas, typically used in LCD membrane switch backlighting and control panels.

 

EMBEDDED LED

Procedure of integrating a surface mount LED into a membrane switch assembly.

 

EMBOSS

A way to supply a raised characteristic to accentuate key surfaces through mechanical and thermoforming of graphical features. This also permits an embedding of a surface mount of an LED inside the switch.

 

GRAPHIC OVERLAY KEYPAD

Control keypads that use graphics for button functions for navigation of machines or process operations. Typically printed sub surface to protect the graphic layer.

 

INTERNALLY VENTED

Membrane switch openings connected to one another to seal the switch from moisture and other contaminants without venting externally.

 

KEY / BUTTON HEIGHT

A measure of the distance from the highest point of a key to the base of the keypad.

 

LIGHT EMITING DIODE (LED)

Embedded in membrane switch layers to illuminate the button.

 

MOISTURE RESISTANCE

A material’s ability to resist the absorption of water from the air or during complete submersion.

 

GRAPHIC OVERLAY

The decorative front layer of a membrane switch or control panel.

 

PILLOW EMBOSS

Creating a raised surface in the graphic overlay over the key area.

 

PINOUT

The schematic that describes the circuit output requirements for membrane switches. Also known as a wire diagram.

 

PRESSURE SENSITIVE ADHESIVE (PSA)

Adhesive materials that bond after pressure without needing heat or solvents.

 

RAIL / RIDGE EMBOSS

Produces a raised ridge circling the key area.

 

SILVER INKS

Tiny particles of actual silver suspended in various substrates that produce conductive patterns on rigid and flexible substrates. Silver is a typical electronic conductor for membrane switches.

 

SPACER

A membrane switch adhesive layer separating the electronic circuit layers with button/switch openings, permitting electrical contact when pressed.

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SUB SURFACE PRINTING

Practice of printing a graphic overlay from the bottom in reverse, so the outer layers protect the graphic.  This is particularly useful in membrane switch applications where the graphic overlay experiences abrasive wear.

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WIRE DIAGRAM

A diagram showing the desired connections to the pinout connector. Usually provided on a 2d drawing with an RFQ. IP Tech can also create a wire diagram for your project if needed.