Anti-Chemical Membrane Front Control Micro Switch Pannel

Kaike manufacture high-performance, high-quality, and highly durable Membrane Switches for the medical device, military, automotive, marine, and OEM industries since 2003. 

Membrane Switch Description

A Membrane Switch is an electrical switch that is used to activate and de-activate an electrical circuit, turning it on or off. They are typically used to communicate a user’s command to the electronic device in order to perform a desired function. The circuit actuation is usually performed by pressing a specific location on the user interface, known as the Graphic Overlay, thus closing the circuit within the printed electronics below. When the membrane switch key is released, the circuit poles separate, and the circuit returns back to an open state. 

A typical Membrane Switch construction is comprised of a central thin film membrane layer. This film is typically made using a Polyester material, although there are a wide range of other material options that can provide added benefits for more extreme environments. The circuitry is constructed using a series of printed conductive inks. It is within this process that separates a Membrane Switch from a Copper etched Printed Circuit Board and other mechanical electronics. The use of printed conductive inks provides the greater cost advantage as well as reduced development and lead time from its copper etched cousin.  There are several different circuit actuation types that can be incorporated into a Membrane Switch from flat non-tactile keys, metal domes for a tactile and audible response, Polyester formed domes as well as capacitive options. Other electronic components can be mounted into a Membrane Switch as well for added functionality. Low profile LEDs, resistors, and capacitors can be integrated into the circuit construction providing more enhanced user feedback options.

Membrane Switch Applications:

• Household appliances (i.e., air conditioner control panel, TV remote control, microwave oven panel...)

• Medical equipment

• Control panel-oriented industrial and manufacturing equipment

• Military equipment

• Aerospace applications

• Automotive controls and panels

• Retail and consumer-related equipment or machines (i.e., exercise equipment, vending machines, gasoline pumps, etc.)

  
  

Construction of Membrane Switch:

• Graphic Overlay

• Overlay adhesive/gasket

• ESD shielding layer (optional)

• Dome retainer and/or circuit spacer

• Surface mounted components (optional)

• Circuit layer

• Rear adhesive layer (with liner)

• Back panel

Membrane Switch Features:

• Custom printed graphics and logos (Graphic Overlay portion)

• Custom shapes

• Multi-layer/sided construction through conductive vias

• Back-lighting

• Surface texture materials (Graphic Overlay portion)

• Embossing (Graphic Overlay portion)

• Actuation options (tactile metal dome, polydome, flat non-tactile, and capacitive options)

• Customizable connector styles

• Window lens coating (Graphic Overlay portion)

• Moisture and dust-resistant sealing

• LED/resistor embedding

• Solution for EMI/ESD/RFI shielding

• Other solutions available for custom Membrane Switches upon request

Membrne Switch Material

The most common overlay materials are either Polyester or Polycarbonate. Polyester has a longer wear-life (greater than 100,000 actuation cycles) and it has greater chemical stability. Polycarbonate shows wear at around 50,000 actuation cycles, although it is still popular because of its lower cost, high clarity and its ease of printing and diecutting. Both types of materials are available in different texture finishes and also high gloss. Certain designs requiring selective texture, can also be accommodated using texture or gloss printable ink. Hardcoating is also available for applications requiring scratch-proof.

Polyester film is available from Autotype and the following material are most commonly used:

Autoflex EB

• Hard coated PET

• Available in gloss or antiglare finish

• High abrasion, chemical and solvent resistance

• Can be embossed

Autotex

• Textured PET

• Available in Fine or Velvet textures

• Can be embossed

• High abrasion, chemical and solvent resistance

• Long flex life

• Can have selective gloss windows

Autotex XE

• Available in Fine or Velvet textures

• Same as Autotex but for outdoor use, and resistant to yellowing an becoming brittle in outdoor UV light

Autotex AM

• Available in Fine texture

• Same as Autotex but with the added benefit of an antimicrobial coating on the surface

Polycarbonate film:

Lexan HP92S (coated film)

• High performance, easily printed and diecut

• High gloss polished surface (92 % light transmission)

• Hard coated and shows strong durability to typical household chemicals

• High abrasion resistance (4 delta haze on Taber abrasion test)

• Pencil hardness HB-F

• Available in gauges between 175 micron to 750 micron

Lexan OQ92S (coated film)

• Offers good optical, good chemical, abrasion and UV resistance over the standard HP92W

Lexan HP92W (Coated film)

• Has a very good chemical and abrasion resistance, but with good UV resistance also. Used for outdoors

Lexan OQ6DA (coated film)

• Hardcoated PC/PMMA film

• 4H pencil hardness

• Excellent chemical resistance and impact resistance

• Excellent light transmission

Rigid Membrane Switch

Membrane switches can be built with a rigid PCB. When many components such as LED, resistors, IC are needed, we recommend a PCB combined with a membrane switch flexible layer.

Electrican Performance of membrane switch panels

Loop resistance:  100 Ohms

Open circuit resistance: 50 MegaOhms Minimum

Contact Rating: 100 mA at 28 VDC

Maximum Load: 1.5 VA nominal

Contact Bounce: 5 milliseconds

Operating Temperature: -45C to 75C