Membrane Switch Introduction

What Is  A ” Membrane Switch”?

A membrane switch is an operating system integrating key functions, indicating elements and operation panel. It consists of panel, upper circuit, isolation layer, lower circuit event to the top layer of graphic overlay. When pressing down the membrane key, the contact of the upper circuit deforms downward, and close the lower circuit. Once the finger  released, the contact of the upper dome rebounds, the circuit is disconnected, and the circuit triggers a signal.

The membrane switch has strict structure, beautiful appearance and good sealing performance, and with damp proof and long service life. Until now they have been widely used in Telecommunication and network, electronic measuring instruments, industrial control, medical equipment, automobile industry, intelligent toys, household appliances and other fields.

Membrane Switch is Mutil-layers Structure Type

As a membrane switch has three layers or more. However, most membrane switches include three to four layers, but also different applications , different layers structure.

Printed Circuit Layer

A membrane switch’s circuit layers are printed circuit that contain electrically conductive material to complete the circuit. So these parts and positioned at the bottom of the assembly.

  As  the circuit layers from a membrane switch have two types,  Flexable FPC printed circuit sheet and Rigid PCB board (corrosion of coated copper circuit plate). Therefore,  FPC print circuit is printed with metallic ink onto a polymer film (e.g., silver-based and carbon ink).  This printed flexable circuit sheet (made of a material like ITO or PET) is as the substrate or lower circuit layer. But PCB board is made from corrosion of coated copper rasin plate. It can be given the entire  assembly structural rigidity and various mounting options (such as connectors for soldered parts).

Metal Domes Conductive Layer

We often see some of dome shaped buttons on membrane switch’s surface,  when you press its buttons, you can feel clearly it is elastic feeling. All of these ,decide these membrane switches, on which buttons , there should be metal dome underneath it . Because they are sealed by insulation layer, so we can’t see them by nake eyes, this is called as metal dome conductive layer.

Various Insulation Adhesion Layers 

Beside of the contact points between dome conductive layer and lower circuit layer, balanced parts should be departed with insulatioln material avoid of short circuit occured. As circuit layers should have waterproof , anti-damp.  So we also make some of custom shaped adhesive layers to meet these membrane switches’ special demands.  Since these adhesion layer are insulated, a close circuit will complete when pressing down the dome key, by it can control various equipments and devices rightly.

Graphic Overlay (indictaion and operation panel)

Since the actual buttons and user interface for operating the switch are located in the top layer of a membrane switch. We regard this layer as the graphic overlay. We print some of  graphic and icons on polyester or polycarbonate film substrates. The engineer select PET and PC  due to its increased durability and improved resistance to chemical corrosion, and electrostatic discharge shielding as well.

The factory numerous ways to create a graphic overlay. They often  have  printed or embossed and is visible from the membrane switch’s surface. Sometimes The graphic overlay could be digitally printed or screen-printed with various colors and letters. The graphic overlay may also be covered with acetate film that has been photochemically patterned with buttons.  That is more cost-effective and offers a wider variety and better quality of graphic effects. (In fact, digital printing is frequently favored due to these factors). Depending on the application’s needs, the graphic overly can have varying degrees of heat resistance, impact resistance, abrasion resistance or corrosion resistance.

The Benefits Of Membrane Switch

Small and portable

The weight of available membrane switches ranges from a few grams to dozens of grams, which is very easy to carry and disassemble.

Sealing and Anti-Electrostatic Interference

Using unique technology, the membrane switch can be waterproof, oil-proof and anti-pollution, but also it is anti-Electrostatic interference and perform other functions.

Excellent electrical conductivity

the circuit of the membrane switch can be printed with carbon paste, silver paste, some of them are embeded by copper,silver and platinum etc.  Such switch can control by coming through micro-electricity to strong electricity power . Reducing electicity shock attack to humen being as soon as possible !

Low cost and mutil-functions

Compared with A mechanical swtich , which control an electronic original device product with many functions, membrane switch’s cost advantage is not comparable to other mechanical switch.

Long service life

Because the materials are made from the membrane switch has good insulation, heat resistance and sealed, even though high resilience. It can print icons and graphic on the reverse side so that the screen printing pattern will not be damaged. About its conductive layers, fraction between the metal dome buttons and circuit contact points is tiny less.

Which Fields Can Membrane Switch Be Used For?

• Household Appliances
• Medical & Healthcare
• Industrial Control
• Car & Automobile
• Instruments & Meters
• Aviation & Marine Control
• Fitness Equipments Field
• Telecommunication and Network

The Most Common Types Of Membrane Switches

PCB/FPC: The circuit of membrane switches are flexible or rigid.

Silicone Rubber Keyboard: Silicone Rubber keypad switches are excellent for device operation controls. Since it is soft and elastic, it can give the user a very nice tactile feeling.

Backpanel: Back panel membrane switches or membrane keypads are flexible. So we fixed it on comparable rigid panel with adhension linear.

Backlighting: LED backlighting, EL lamp, LGF(Light Guide Film) and Fiber backlighting.

Tactile Feedback: Tactile metal domes can be embedded into membrane switches and offer a snap-action feel to improve tactile feedback.

Custom Membrane Switch Solutions

LuphiTouch is a professional membrane switch and custom keypad producer in China.

It can produce various custom tactile membrane keypads and custom keypads that match with customer’s special demands. We design and create custom membrane switches and membrane keypad technologies that satisfy with different customers demands and aesthetic needs.