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| ABRASION RESISTANCE Ability
to resist surface wear. ABS Acrylonitrile Butadiene Styrene: a thermoplastic composed of styrene and acrylic resin. ACCELERATED AGING A test methodology that simulates long term environmental effects. ACTUATION FORCE Force required to collapse the walls of a rubber keypad, metal or polyester dome. ADHESION The molecular force of attraction between unlike materials. The strength of attraction is determined by the surface energy of the material. The higher the surface energy the greater the molecular attraction, the lower the surface energy the weaker the attractive force. AIMCAL Association of Industrial Metalizers, Coaters, and Laminators. AMPERE [AMP] A standard unit of current. Defined as the amount of current that flows when one volt of EMF is applied across one ohm of resistance. An ampere of current is produced by one coulomb of charge passing a point in one second. ANALOG What ANA tosses into the fire. ANSI American National Standards Institute; a standard setting agency of the United States, which approves the design, and performance of electrical/electronic components. AQL Acceptable quality level. ARC RESISTANCE The resistance to current flow across the surface of the material. ASTM American Society for Testing and Materials. AUTOTEX Trademark for Autotype Industrial Films polyester graphic overlay film. AWG American Wire Gauge. A wire diameter specification. The smaller the AWG number, the larger the wire diameter. BACKING ADHESIVE/mounting adhesive. The adhesive applied to the rear surface of a membrane switch to attach to the customer application surface, normally between .002-.005 thick. BGA Ball grid array. BOND STRENGTH Amount of adhesion between two surfaces. BREAKDOWN VOLTAGE The voltage at which the insulation between two conductors is destroyed. CAD/CAM Computer aided design/Computer-aided manufacturing. CAPACITANCE The property of conductors and dielectrics which allows the storage of an electrical charge when voltage is applied. ASTM F1663-95 CAPILLARY ACTION The effect of surface tension that draws a liquid into a small opening. CARBON/GRAPHITE INKS Specially
prepared suspensions of carbon black; these systems are employed for lower cost when the conductivity of a metal base system is not
required. Often printed over silver circuitry to reduce the potential for silver
migration, also employed for printed resistors. CERTIFICATE OF COMPLIANCE(C OF C) A certificate generated by a quality control department confirming that the product being shipped meets the manufacturing document. CIELAB ( International Committee on Illumination) The most widely recognized color matching system for describing colors with numbers. A Physical color chip is usually required along with the numeric coordinates to match the color using the system. CLINCHER CONNECTOR® Proprietary name for a Flat Flex connector line manufactured by BERG Corporation. CONDUCTIVE INK See SILVER INKS. CONDUCTIVITY The ability of a material to allow electrons to flow measured by the current per unit of voltage applied. CONDUCTOR A material that offers low resistance to the flow of electrical current. CONFORMAL COATING Sprayed or dipped. A thin layer of material applied to electronic products to protect it from moisture or other damaging environments. CONTACT BOUNCE Intermittent contact opening and closure that may occur after switch operation. See ASTM F161-95 CO-POLYESTER A Graphic overlay film composed of polyester and polycarbonate polymers. CROSS-LINK A chemical bridge formed between modular chains increasing their strength and heat resistance. CROSS-OVER An intersection of
conductors insulated by a dielectric material. CSA Canadian Standards Association. CURRENT, ALTERNATING (AC) An electric current that periodically reverses direction of electron flow. The rate at which a full cycle occurs in a given unit of time (usually a second) is called the frequency of the current. CURRENT, DIRECT (DC) Electrical current whose electrons flow in one direction only. It may be constant or pulsating as long as it’s movement is in the same direction. DEAD FRONT Cosmetic feature of a graphic overlay allowing for a display feature to be visible only when backlit. DIE CUTTING Process for blanking or cutting sheet or roll materials to pre-determined shapes for membrane switch components, graphic overlays and labels. DIELECTRIC BREAKDOWN Any change in the properties of a dielectric that cause it to become conductive. Normally a catastrophic failure of an insulation because of excessive voltage. DIELECTRIC INKS Used in printing protective and insulating patterns on conductive printing to selectively isolate regions from electrical contact with other conductors. This category of material is used for “cross-overs” and tail insulation on membrane switches. Material is usually screen-printed. DIELECTRIC STRENGTH The maximum voltage insulation can withstand without rupture. DIELECTRIC An insulating (non-conducting) medium. DIELECTRIC-WITHSTAND VOLTAGE Maximum voltage a dielectric can withstand without a change from a voltage discharge or specified change in insulation resistance. ASTM F1662-95 DIN Deutsche Industrie Normenausschussan; association that sets standards for the electronics industry. DOME RETAINER An adhesive layer designed to hold Metal Domes in the keyswitch DUAL DUROMETER Silicone rubber keypads manufactured using a 2-shot molding process, allowing for the use of materials with 2 hardness characteristics. EIA Electronic Industries Alliance. EL LAMPS A thin (.010”-.025”) illuminating device employed to light large areas, commonly used in LCD, control panel, and membrane switch backlighting. ELECTROSTATIC Pertaining to static electricity, or electricity at rest. An electric charge for example. EMBEDDED LED The practice of encapsulating
a surface mount LED into a membrane switch
construction. EMBOSS Mechanical and thermoforming of graphic features, providing a raised feature for accenting key surfaces, logo’s, and to allow for embedding of surface mount LED’s within the switch. EMBOSS, RACETRACK See EMBOSS,RAIL EMBOSS, RAIL Creates a raised ridge around the perimeter of the key area, usually .010” to .015 high. EMBOSS, PILLOW Creates a raised
surface in the graphic overlay over the entire key area, usually .010”
to.015”high. EMBOSS, PLATEAU See EMBOSS, PILLOW EMI/RFI/ESD SHIELD Printed conductor pattern or separate aluminum or copper film employed in membrane switch designs to reduce the effects of electromagnetic and radio frequency interference. EMI Electromagnetic interference. ASTM F1812-97 EUTECTIC SOLDER The most common solder alloy because of its low melting point (183F) composed of 63% tin and 37% lead. EXTERNALLY VENTED Keyswitch openings are connected to each other and to the outside environment. This method of venting allows the air chamber to evacuate and refill. See ASTM F1762-96 FARAD A unit of capacity that will store one coulomb of electrical charge when one volt of electrical pressure is applied. FEDERAL STANDARD 595A Color matching system developed by the federal government. The color catalog has a limited number of colors with a range of gloss levels. FIBER OPTIC BACKLIGHTING Illuminating device employed to light large areas. Strands of clear fiber are woven and bundled, after polishing the fiber ends are illuminated by an LED or Halogen lamp. FLAT FLEX CONNECTOR [FFC]
Connector type commonly used to terminate membrane switch
circuitry. FONT A set of characters having a unified design. FORCE TRAVEL CURVE The relationship between actuation force and switch travel, usually expressed as a line graph. GLOSS LEVEL The degree of shininess of a substrate, usual specified in percentages for example 75% gloss, 90% gloss, etc. GRAPHIC OVERLAY See OVERLAY. GULL WING A type of lead form, which extends from the side of the device and has an L-shaped bend at the end. HALIDES Compounds containing fluorine, chlorine, bromine, iodine or astatine. They me be part of a flux system as activators and as corrosives must be removed. HB-94HB Underwriters Laboratories flame retardant specification (horizontal burn) HSE High surface energy. Hz Hertz. IC Integrated circuit. IDC Insulation displacement contact. IEC International Electrotechnical Commission IMPEDANCE The opposition to alternating current flow expressed in ohms and designated by the symbol Z. INSERT LEGEND (INSERT GRAPHICS) A design feature allowing for changes to nomenclature and symbols by the client or end user. The feature is accomplished by creating a pocket in the membrane switch assembly to allow for an insert card. INSULATION RESISTANCE The electrical resistance between two test points. ASTM F1689-96 INTERNALLY VENTED Keyswitch openings are connected to each other but not to the outside atmosphere. This design approach is used to seal the switch from moisture and contaminants. ISDN Integrated Services Digital Network. ISO International Standards Organization. Known for the development of a series of standards called ISO 9000 for developing Total Quality Management, and creating a continuous Quality Improvement Process. ISO 9001 Provides a model for the design and development process, as well as production, installation and servicing of a product. FDA GMP requirements are identical to the 1994 standard. ISO 9002 Provides a model for a company only in the manufacturing, installation, and service areas. No design controls are addressed. ISO 9003 Quality assurance in product final inspection and testing. ISO 9004 Guideline to overall quality management. ITO Indium Tin Oxide, a thin film conductive material vacuum deposited on the surface of a film substrate. Material is often the base material for resistive touchscreens and luminescent lamps. KEY HEIGHT The measured distance from the bottom (base) of the keypad to the top surface of the key. KEY TRAVEL The distance a switch moves to close an electrical contact, expressed in inches or MM. LCD Liquid crystal display. LEXAN® General Electric (GE) registered trademark for polycarbonate film. LIGHT EMITTING DIODE A
semiconductor device that emits incoherent light formed by the P-N junction. The light
intensity is roughly proportional to electrical current flow. LSE Low surface energy. MEMBRANE SWITCH A momentary switching device in which at least one contact is on or made of, a flexible substrate. METAL DOME Stainless Steel Disc or
element. One of several approaches used to produce tactile
response in membrane, mechanical switches, and elastomeric switches. MHz Megahertz. MIL-SPEC Military specification. MOISTURE RESISTANCE The ability of a material to resist absorbing moisture from the air or when immersed in water. MONOMER The chemical unit used in building a polymer. MP Modified performance. An adhesive classification of 3M products. MUNSELL Color matching system which defines color by three attributes; hue, value, chroma. Fifteen hundred color samples are available as opaque pigmented films. MYLAR® Dupont trademark for polyethylene terephtalate (polyester) film. NANOSECOND One billionth of a second (10^-9 seconds). NEMA National Electrical Manufacturers Association. NOMEX® Dupont trademark for a temperature resistant, flame retardant nylon. NON-TACTILE Membrane switch constructed without snap action. NTC Non-top coated. NYLON An abrasion-resistant thermoplastic with good chemical resistance. OHM’S LAW Stated E=IR, I=E/R OR R=E/I. The current in a circuit is directly proportional to the voltage E, and inversely proportional to the resistance R. OHM The electrical unit of resistance. The value of resistance through which a potential difference of one volt will maintain a current of one ampere. OPERATING FORCE The amount of force required to complete a switch closure. OVERLAY 1.Decorative front layer of a
membrane switch or control panel. 2 Chickens making too many eggs. OVER-TRAVEL The additional travel of a rubber keypad or metal dome after making contact with the circuit. PAL-programmable array logic. PANTONE MATCHING SYSTEM (PMS) Color matching
system originally developed for the offset printing industry, commonly used in the membrane switch industry for its broad acceptance, range of
colors and ease of use. Over 1000 colors are cataloged. PARYLENE Generic name for members of unique polymer series. The basic member of the series, called parylene N is poly-para-xylylene, a completely linear highly crystalline material. Material is deposited from the vapor phase by a process similar to vacuum metalization. Material is used as a conformal coating for silicone rubber keypads and electronic assemblies. PCB printed circuit board. PET Polyethylene terephthalate; Manufactured as a film for graphic overlays, labels. See also: MYLAR® PINOUT The schematic describing the circuit output requirements for a membrane switch or other electronic device. PL Polyolefin liner. POLYCARBONATE Graphic overlay film widely used for control panels POLYCHLOROPRENE Chemical name for neoprene POLYESTER DOME A spherically formed element in polyester circuit material to provide tactile response in membrane switches. Usually the domes are formed in arrays or sets to match the key configuration of the keypad. Polydomes. POLYESTER Bi-axialy oriented polyethylene terephthalate film. (PET) POLYETHYLENE A thermoplastic material having excellent electrical properties. POLYVINYL CHLORIDE (PVC) A general purpose thermoplastic film PRESSURE-SENSITIVE Adhesive materials which bond with the application of pressure alone and do not require activation by heat or solvents. PSA PRIMER Preliminary coating applied to a surface to enable an adhesive system to bond to a substrate. PSA Pressure Sensitive Adhesive. PWB Printed wiring board. RAM Random Access Memory. REAR ADHESIVE The mounting adhesive for a membrane switch normally .002-.005 thick RESISTANCE In DC circuits, the opposition a material offers to current flow, measured in Ohms. RFI Radio Fequency Interference. RTV Room Temperature Vulcanizing. RUBBER KEYPAD Type of switching device molded from silicone rubber. SCREEN PRINTING Printing process
using a mesh stretched over a frame allowing ink to selectively pass through by using a
stencil. The process most commonly used for producing graphic overlays and membrane switch circuits. SCREEN TINT Printing method used to create shading effects. SECOND SURFACE PRINTED Inks are applied to the non-exposed side of the film to allow for the film to protect the inks from scratching or damage. SELECTIVE TEXTURING The creation of surface effects on matte or gloss films normally applied using the screen printing process. SILICONE RUBBER Rubber made from silicone elastomers and noted for its retention of flexibility, resilience and tensile strength over a wide temperature range. SILVER INKS specially prepared suspensions of finely milled silver particles in a variety of resin systems are used widely to produce conductive patterns on flexible and rigid substrates. A commonly used conductor material for membrane switches. SM Surface mount device. SMT Surface mount technology. SPACER An adhesive layer of a membrane switch used to separate circuit layers and to provide keyswitch openings allowing for conductors to contact each other when depressed. SPST Single Pole Single Throw. Normal circuit configuration in a membrane switch. STATIC SHIELD Printed conductor pattern or separate aluminum or copper film employed in membrane switch designs to reduce the effects of static discharges. STEEL RULE DIE Consists of a .750-.875 thick die-board (plywood or aluminum construction) with .937” high knives inserted into laser cut groves. STROKE Distance from the contact surface on the switch to the circuit pattern on the mating contact. SUB-SURFACE PRINTING See SECOND SURFACE PRINTED SURFACE-RESISTIVITY The resistance of the surface of an insulating material to the flow of direct current. SWITCH CIRCUIT Membrane switch component containing conductors, normally screen-printed using polymer thick film resins. TACTILE RESPONSE See TACTILE SWITCH TACTILE SWITCH A switch or switch assembly providing a positive snap-action response. The response can be achieved through the use of stainless steel domes embedded in the membrane switch, or polyester domes formed in either the circuit or graphic overlay layers. TEAR STRENGTH The force required to initiate or continue a tear in a material under specified conditions. Standards used for overlay films; ASTM D1004, ASTM D1922. THERMOPLASTIC Plastic materials which can be made to flow repeatedly with the application of heat. THERMOSET Plastics, which once cured, cannot be made to reflow. THIXOTROPHY The property of a coating or ink, which has a low viscosity when agitated, but thickens when agitation ceases. VAC Volts alternating current. VAPOR PHASE SOLDERING A soldering process that uses the latent heat of vaporization of a liquid as its energy source. VDE Verband Deutscher Elektrotechniker of Germany VISCOELASTIC ORDERING The alignment of stretched chains within a polymer along the axis of deformation, leading to a dramatic improvement in the strength of the film along the axis. VISIBLE LIGHT TRANSMISSION (%) The ratio of the amount of total visible solar energy (370-780 nanometers) that is allowed to pass through a filter, to the amount of total solar energy falling on that filter. WATT A unit of electrical power. One Watt is equivalent to the power represented by one ampere of current with a pressure of one volt in a DC circuit. WAVE SOLDERING Widely used process for soldering thru-hole PCB assemblies. ZIF Zero Insertion force.
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