Glossary of Terms

Actuation Force – The maximum force measured prior to or including the point at which keypad contact closure is achieved.


Backlighting – A flexible layer within a membrane switches construction that illuminates select areas of the overlay, such as text or graphic symbols. Examples of backlighting methods are E.L. (electroluminescent) or fibre optic.


Circuit – Functioning component (sub layer) of a membrane switch. Typically made of a silver conductive ink printed on polyester. Also can be a flexible copper circuit, a PCB or polyester printed with other conductive materials.


Contact Bounce – (Make) Point at which specified resistance is achieved.


Dead Front – Printing translucent ink in an area so that the graphic is visible only when backlit.


Density – The degree to which light transmits through a colour or transparent window. The higher the density, the less light will be transmitted.


Dielectric Strength – The voltage that an insulating material can withstand before breakdown occurs, usually expressed as a voltage gradient (such as volts per mil.)


E.M.I. (also R.F.I) – Electromagnetic Interference (Radio Frequency Interference) Radiated energy from electrical devices, lightning and similar sources which interferes with the proper operation of electronic circuitry.


E.S.D.  Electrostatic Discharge – transfer of high potential electrical charge between objects by contact or through air.


Files – Information or documentation created electronically by computer.


Font – A set of characters having a unified design.


Gloss Level – The degree of shininess of a particular material, usually specified in percentages such as 75% gloss, 90% gloss, and so forth.


Halftone – Image made of a pattern of various size and shape dots (newspaper photograph) rather than continuous gray.


Image Setting – The process by which electronic files are transferred to film or paper directly from the computer (computer onto film technology.)


LED – Light Emitting Diode.


Membrane Switch – A momentary switching device in which at least one contact is made of a flexible substrate.


Moisture Resistance – Ability of a material to repel moisture either from air or when subjected to water.


Non Tactile Switch – A switch assembly that has a tactile ratio equal to zero.


Overlay – Top layer of a membrane switch (the graphic interface between device and user) generally made of polyester or polycarbonate.


Pad Emboss – A raised area on an overlay, which defines an entire graphic. (i.e., a full keypad of L.E.D. window.)


Proof – A paper simulation of what a screen printed overlay will look like, submitted to a customer for approval.


Polyester Dome – A keypad on a membrane that has been dome embossed on the overlay or top circuit layer to add tactile feedback when the switch is activated. The dome shape, which is usually formed by a hydro forming process, can vary in size and shape to achieve a desired "force" and "tactile feedback" of the keypad.


Prototype Tooling – Method of fabricating prototype components without using steel rule dies (hard tooling) allowing changes before production runs without expensive tooling charges.


Rail Emboss – A raised area on an overlay which defines the perimeter of a graphic. (i.e., perimeter of a keypad or a border.)


Schematic – A drawing showing electrical interconnections and functions of a specific circuit arrangement.


Screen Printing – Method of printing by forcing ink through a mesh selectively. This is done by closing parts of the mesh with a stencil.


Screen Tint – Area of image printed with dots so ink coverage is less than 100%, simulating shading or a lighter colour.


Selective Texture – A transparent velvet finish printed on specified areas on an overlay to accentuate design elements such as windows, keypads or graphics.


Shield – A layer of polyester material that is either laminated with aluminium or printed with conductive ink to protect a switch from E.S.D. or E.M.I. interference.


SMD – Surface Mount Device.


S.M.T – Surface Mount Technology.


Specified Resistance – Maximum allowable resistance measured between two terminations, whose internal switch contacts, when held closed, complete a circuit.


Sub Surface Printing – Imaging on the back (second surface) of an overlay so the printed graphic is protected from wear by the actual material.


Tactile Ratio – A measure of tactile response.


Tactile Response – A sudden collapse or snapback of a membrane switch prior to contact closure or after contact opening.


Tactile Switch – A switch assembly that provides a tactile ratio greater than zero. Tactile switches give the user immediate physical feedback that the switch has been activated. Tactile feedback on a membrane switch can be achieved by using a stainless steel dome or a polydome construction.


Termination – How a switch is connected to the device it activates.


Translucent – Partially transparent. Having the property of diffusing light.


Transparent – Having the property of transmitting light without appreciable scattering so that objects beneath are entirely visible.