Suppliers of membrane switches and keypad services fabricate assemblies using flexible membranes, domed or flat switch profiles, and tactile and non-tactile switches and panels. Product capabilities of suppliers of membrane switch and keypad services can include numerical keypads, graphical keypads, control panels, and membrane switch overlays. 

• Numerical keypads include numeric or alphanumeric switches and keypads for data entry, operation of menu-driven software, entry of word commands, etc. 
• Graphical keypads are image or graphic-based keypads for machine or process navigation and operation. Graphics may conform to international standards or be customized to the application. Common graphics include arrows, pictorials of machine operations or processes, etc. 
• Control panels include full function panels for monitoring and control of machine, process, or system variables and commands. May include inputs, outputs, and interfaces tailored to the application. 
• Membrane switch overlays are graphical or alphanumeric coverings for keypads indicating key or switch functions.

Materials

Materials of construction for membrane switch and keypad services include polyester, polycarbonate, rubber or silicone, and metal. Some suppliers provide texturing such as pebbling, knurling, ridges, or other texturing for aesthetic or operator tactile identification purposes. 

Features

Features include backlit switches, LED indicators, outdoor environment, hazardous environment, vandal proof, washdown capable, EMI/RFI protection, ESD protection, and embossed switches.

• Switches or keys are backlit for use in dark or inconsistently illuminated environments. Backlighting is frequently accomplished with an electroluminescent panel in the keypad or panel. 
• Switch, or operation, status can be indicated by light emitting diodes (LEDs) incorporated into the keypad. Possible uses include signifying operation (e.g., red = stop, green = go), process status, verification of system functions, machine interlocks, alarm conditions, etc.
• Switch, keypad, or panel can be designed for outdoor use and often involves special sealing and resistance to water, sunlight, and temperature variations. Hazardous environment switches need special materials and sealing considerations for use near chemical, very high temperature, areas where fire or explosion are possible, etc.
• Vandal-proof keypad, or panel casings, are resistant to unauthorized tampering, access, disassembly, etc.
• Some switches are designed for full washdown; may include materials immune to degradation by detergent, robust sealing features, etc. 
• Some switches can measure for protection against electromagnetic interference (EMI) and radio frequency interference (RFI) including shielding and grounding of electronics and electrical circuits and conductors. This is often required for regulatory compliance certifications. 
• Protection against electrostatic discharge (ESD) may be accomplished with static-dissipative or conductive elements in the switch material, special electronics grounding practices, etc.
• Embossed switches have graphics or alphanumerical characters that are raised or embossed from the switch surface.

Applications

Membrane switch and keypad services are important in many different industries. These include aircraft or aerospace, automotive, building controls, communications and electronics, financial services, manufacturing or automation, medical, retail, and security and identification. Supplier capabilities can include graphical design and layout, PCB design and layout, just-in-time delivery, samples or short runs, life cycle testing, and screen printing. 

Standards

Certifications met by suppliers of membrane switch and keypad services include AS 9000, CE, ISO 9001, ISO 9002, QS-9000, UL/CSA, and MIL-SPEC/STD.

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Image credit:

Aaron Siirila / CC BY-SA 2.5