Dustproof Polyester Industrial Control Membrane Switches

What is membrane swicth keypad?

A membrane switch is an electronic switch for turning a circuit on and off.   Membrane switches differ from traditional mechanical switches in that they are printed circuitry taking up less space and providing a lower profile than a traditional mechanical switch.  This also improves longevity of the switch’s lifecycle and makes them more affordable as they do not have the plastic and copper moving parts of a traditional mechanical switch.  Membrane switches are also easy to clean and have less opportunities for water intrusion making them ideal for a variety of industries.  Some examples of membrane switches might be controls for consumer appliances, key pads at gas pumps, and controls on a lot of medical devices. Membrane switches can be very thin and can offer almost any key configuration needed. Membrane switches operate when two layers of printed circuitry and pressed together closing the circuit normally open circuit.

Membrane Switch technologies including:

Tactile & Non-tactile, Metal Dome & Polydome

Polymer-thick Film, Polyimide, or FR4 substrates

LED, EL, and Fiber backlighting

AMP, Nicomatic, FCI connector systems

Harsh & Rugged Environmental solutions

Membrane Switch Types:

• Flat switches

• Tactile switches

• Switches with PCB assembly

• Switches with keypad assembly

• Switches mounted to metal backer (metal dome and polydome constructions)

• Switches with micro motion and backlighting

• Switches with rugidized options

• Switches with plastic housing

• Medical membrane switches

• Embossed switches

• Switches with rigid & flexible substrates

• Switches with EMI/RFI shielding

Membrane Switch Construction

Membrane switches made up of thin flexible plastic layers including polyesters and polycarbonates. These layers are built up and sandwiched together to construct the whole switch assembly.  Membrane switch construction ranges from fairly simple to very complex depending on the switches functionality and the environment it will be required to operate in. At a minimum, the switch assembly would require a printed graphical overlay, adhesive layers, a printed upper circuit layer, spacer materials, a printed lower circuit layer, another adhesive layer, and filler for the termination tail.  More complex assemblies can include backlighting layers, dome layers, shielding layers, and other layers for various product requirements. Membrane switch circuits are screen printed using silver or carbon conductive inks to create a circuit layer.  Graphical layers can be either screen printed or digitally printed. Metal domes can be added to provide tactile feedback to the user.  LEDs can be used in conjunction with other materials to backlight a membrane switch. Membrane switches can also be completely flexible circuit assemblies, adhered to a backplate, or built up on top of a rigid PCB.

Membrane Switch Options

Custom color matching and intricate graphical layer design – Our team has the experience to make the face of your product stand out from the field.

Tactile domes – Tactile domes provide the user with a snap or click sound and sensation when depressed. Membrane switches do not have to have this feature and have a longer potential life expectancy without tactile domes.

Embossed Keys – Key areas can be embossed, or raised or lowered, to give a feel guide to where the key is. This can be a pillow or ring emboss.

LED Backlighting – Custom backlighting solutions for your product can include; led light guide films, EL Lamps, and fiber optics. While LED light guide films can provide the most even lighting options, each application has its advantages and we can help guide you to the best solution for your project.

Display windows – These can be incorporated into a variety of shapes and sizes and can be tinted or clear.

Shielding – Membrane switches can be built with EMI, RFI, and ESD layers to protect your product.

Backplates – Membrane switch assemblies can be stand alone flexible circuits or built up on rigid backplates including aluminum, steel, or other options.

PCB’s – Membrane switches can be built up on PCB’s that can also act as a rigid backplate.

Termination – A variety of terminations can be used to mate a membrane switch to your product. Our team can match your specifications or help guide you in the right direction.

Membrane Switch Design Consideration:

Material selection

We offers a range of hard coated and textured polyester and polycarbonate films. These substrates have been designed specifically for the graphic overlay film on membrane switches, and range in finish from high gloss to velvet matte. Both product ranges are screen printable on the second surface; they are solvent, chemical and scratch resistant on the first surface. Polyester is the most popular choice as it is more robust, providing superior chemical resistance and allowing for up to 5 million actuations over its lifetime, as opposed to polycarbonate, which is only rated for up to 100,000 actuations. 

Color matching

The Pantone Matching System (www.pantone.com) is the most popular for graphic art applications. Kaike has the ability to match Pantone, custom and transparent colors with our digital presses. There are separate matching criteria for both opaque and transparent colors.

It is important to remember that matching screen printed overlay colors to surrounding components is difficult. For this reason, we are using state-of-the-art color matching equipment in the X-rite Ci7600 spectrophotometer. As long as we have a control color to match against, we can achieve a color match under 1.0 delta in the CIE Lab color space. We are capable of matching Pantone colors, custom colors, as well as transparent colors for windows. We also have the capabilities to do transmission and density readings.

Embossing

We can provide either pillow (pad) or rim (perimeter) key tactile designs into polyester or polycarbonate overlays. This process requires a male/ female die set. Overlay embossing dies are manufactured with sophisticated tolerances to allow for material flow.

Our design staff will precision-calculate a die for your application.

Windows

Display windows are typically transparent and they can be either clear or color tinted. LED windows can be either transparent(with or without color added) or translucent. A transparent color is optically clear and used to filter backlight displays. The transparent color reduces the "blooming effect" of the display. A translucent color is normally used for diffusing an indicator light or backlighting for printed graphics, such as an instrument cluster that is backlit.

Selective surface texture/hard coat

Kaike offers hard coat films that are ideal for membrane switch overlay applications. These films are polycarbonate and polyester substrates that have been specially treated so that their surfaces can be selectively textured, embossed or printed with UV inks. Available in finishes ranging from glossy clear to textured matte black; hard coat films offer a range of display options.

Hard coat films resist scratching and staining from a broad spectrum of foods, household cleaners and aggressive chemicals. For special applications, such as medical equipment, our hard coat films may be embossed or otherwise thermoformed without sacrificing performance characteristics.

We print inks specifically designed to give a decorative texture effect on first surface polyester or polycarbonate used for membrane overlay applications. Also we offer many state of the art forms of texture coats from very fine to course. We can custom match your texture. With the new technologies in UV inks we can provide a texture coat that is very durable and will withstand marring.