For the resistive membrane switch, it needs the finger to give a force to press the buttons then the metal dome under the button will contact the conductive pads on the bottom circuit layer, then become a circuit loop and made the circuit be connected and then triger the relevant function.
CREATING CONNECTIONS BETWEEN HUMAN AND MACHINE
What is membrane switch?
Membrane switch is a kind of subassembly consists of graphic printed top overlay, adhesive spacers, dome layer, circuit layer and rear adhesive, which has the switch function. Press down the button, the metal dome or Polydome will contact the conductive pad on the circuit layer, then it produces a circuit loop and then triger related electrical function. When unpress the button, the circuit loop disconnected and then the function closed. Thin membrane switche have advantages, like the thin structure, flexible, light weight, exquisite appearance, colorful, waterproof, dustproof, anti-corrosion, easy to clean, longworking life etc. which are widely used in medical , beauty, household appliances, industrial control, automotive, defence, aerospace, marine, instruments, measuring meters, genset controllers and other fields.
Membrane switch is more flexible to customize as per end customer's needs compared with the traditional switch. It can be made to any shapes and thickness which can meet the end user's widely design requirement. The end users also can define any kind of graphic and colors they want on the overlay and the membrane switch always can achieve them very easily and flexibly. In addition, the membrane switches also can be incorporated with rubber keypads, metal backers, plastic panels, touchscreens, LCD displays, rigid circuit boards, copper FPCs, PCBAs etc. to be an more integrated and precision interface switch panel modules.
We are ISO13485, ISO9001, ISO14001, ISO45001 certified manufacturer. Rely on our advanced manufacturing equipments, state of-the-art technologies, high-grade clean production room, skillful workers and strict quality control measures, LuphiTouch becomes one of the world's leading manufacturer for different knds of interface membrane switch subassembly products. With our unlimited design and manufacturing capabilities, LuphiTouch is able to provide our clients with high quality resistive membrane switches and capacitive switches to meet their needs as their devices' user interfaces and front panels.
There are many types of membrane switches. It can be divided into a variety of different types as per different standard of classification.
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There are many types of embossing for buttons, like round embossing, flat embossing, pleatue embossing, frame embossing, letters embossing, debossing and others. In theory, we can tailor the embossing for whatever the designer intends. The height of the embossing is usually between 0.35mm and 0.45mm, but sometimes for some special application, it also can emboss to 0.7mm or even more higher, like 1.0mm, 1.2mm etc. But if the embossing is too high it will impact the life of the button, and also impact its tactile feeling.
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While, due to it no need the force to press the button and just need light touch then triger function for the capacitive membrane switch, then it has been widely used in household appliances, consumer electronics, beauty industry etc. fields.
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Of course, this distinction is not absolute. Both resistive and capacitive membrane switches have their own advantages and disadvantages. You need select the proper one according to the real situation of your products. For example, the cost control, target market analysis, product's using environment etc.
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But for the capacitive membrane switch, which no need any force to pres the button and just need lightly touch the button, then through the produced capacitance to make the circuit be connected and then triger relevant function. Due to it needs a force to press the button to make the circuit be connected for resistive membrane switch, which is not easy to happen wrong touch, then it will be mainly used in those fields which have very high safe requirement, like the defence, aerospace, marine control, industrial control, medical, genset control, mechanical equipment, machineries etc.
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Except for the metal dome tactile membrane switch, the other one is Polydome switch. Polydome means directly make embossing on the graphic overlay and top circuit (for some applications also only emboss the overlay). For this kind of tactile membrane switch, the tactile feeling is totally given by the embossing, because of that no metal dome under the button. So the tactile feeling is usually weaker than metal dome switch. In addition, metal dome has more higher life than Polydome. Metal dome has more than 1million stroke life, but Polydome only has 200-400 thousand times life. So in current market, the needs to tactile membrane switch is usually just metal dome tactile switch.
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As to the non-tactile membrane switch, it usually means those membrane switches which no embossed buttons(namely flat buttons, or only emboss letters, or borders) and also no metal domes placed under the overlay. Due to no any press fedback for this kind of membrane switch, which caused the end application experience is not good, so in recently years it gradually eliminated by the market.
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As to the rigid membrane switch, it usually can be divided into two types again. One type is using the rigid PCB as its circuit layer. Due to the PCB itself is rigid, so the membrane switch which uses the PCB as the circuit is rigid too. Th other type is just adding a rigid support layer on previous introduced flexible membrane switch.
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The common used support layer materials are PC, PMMA, FR4, tempered glass, stainless steel, Aluminium etc. For some clients, their design requires that the membrane switch has sufficient rigidity and supporty, which is usually achieved by just adding such a support plate.
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For some mechanical equipments, it usually requires some hardware components to be applied to the HMI port, so the hardware backplate, screws, bolts and membrane switch are often integrated into a rigid interface switch subassembly.
The structure of the standard resistive membrane switch and its raw materials
The standard resistive membrane switch is consists of 6 layers, which are top graphic overlay, overlay spacer, dome retainer circuit spacer, circuit layer and back adhesive. The details like below:
Graphic Overlay: It is just the top front layer which is showed before users directly. It requested to make different exquisite graphics and letters printing. It can be silk screen printed or digital printed.
The graphics are printed on reversed side. In addition, it also usually requested to make different kinds of embossing for buttons, Logo, symbols etc. on overlay. Due to the overlay is directly exposed outside, and also plays the marking, identification and switch role, so its material selection is very important. It should be high temperature resistance, corrosion resistance, high transparency, high chemical stability, high tenacity, waterproof etc.
For those used outdoors membrane switch, the overlay material also need be UV-resistant. The common used materials are polyester(PET) and polycarbonate(PC). PET has more better performance than PC, so the PET has the highest using ratio as the overlay material. Nearly 95% of membrane switches we manufactured for our clients who come from America and Europ are used PET materials. The material thickness usually is 0.15mm, 0.18mm, 0.2mm and 0.25mm. We use Autotex PET, Lexain PC and other world famous brands.
Dome Retainer: This layer is working as a holder to fix the metal dome to make them not be shifted. If the metal dome happened the shifting issue, then it may caused the membrane switch lost its function when pressed that button. The dome retainer layer is usually PET with thickness from 0.05 to 0.125mm around.
Circuit Spacer: This layer is used to connect the top dome array and bottom printed circuit layer. Similar to overlay spacer, its materials are usually 3M and Luxking and its thickness is from 0.05 to 0.45mm around. For the backlighting membrane switch, it also need use black adhesive for this layer.
Circuit Layer: This is the most important layer for a membrane switch. Usually the circuit layer of the membrane switch is divided into top circuit and bottom circuit. For the standard membrane switch with metal domes, it usually only has bottom circuit. And for Polydome membrane switch or the 6 layers membrane switch without metal domes, it usually has the op circuit. For more details about this, please inquiry to our sales engineer. The circuit material usually is the PET with very good thermostability. On the circuit PET material, it need print silver circuit lines, conductive soldering pads, contact fingers on tail end, and usually also need print the carbon paste and dielectric UV ink to prevent short circuit and orxidation. It is also possible to assemble SMD electronic components on PET circuit, like the LEDs, resistors, capacitors, etc. The PET circuit is usually 0.125mm, but sometimes also can use 0.1mm or 0.188mm.
Back Adhesive: It located at the rear side of the membrane switch. It is a kind of double sided adhesive, which is used to stick the membrane switch to the client's products. It can sticked on many different materials, like plastic, metal, glass etc. What kind of adhesive should be selected here depends on the installation surface of client's products. But the common used back adhesive include 3M467 and 3M468 which can meet most of assembly situation.
What kind of resistive membrane switches and solutions we can do for our clients?
LuphiTouch® is one of the world leading manufacturer for many different kinds of resistive membrane switches with cutting-edge technology.
Our manufactured resistive membrane switches served medical, aerospace, marine control, defence, industrial control, networking, telecommunication,
energy, household appliance, instruments, meters etc. fields. Here are the resistive membrane switches and solutions we can do for you.
01
PCB Membrane Switch Subassemblies
January 17, 2020 / Interview
PCB Membrane Switch Subassemblies
If the circuit layer of the membrane switch is rigid printed circuit board (short for PCB), then it is a kind of PCB.……
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02
FPC Membrane Switch Subassemblies
January 17, 2020 / Interview
FPC Membrane Switch Subassemblies
If the circuit layer is flexible printed circuit board (short for FPC), then it belongs to FPC membrane switch group.……
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03
January 17, 2020 / Interview
Membrane Keypad Epoxy Dome Solutions
For the HMI switches, silicone rubber keypad plays a very important role. It can be separately used or.....
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03
January 17, 2020 / Interview
Outdoor Application Membrane Switches
Outdoor is the very common application environment for many kinds of equipments and devices.......
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03
January 17, 2020 / Interview
Medical Membrane Switches & Keypads
LuphiTouch® is an ISO13485 medical quality management system certified manufacturer.......
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03
January 17, 2020 / Interview
Backplane Membrane Switch Subassemblies
The backplane membrane switch subassemblies are usually applied where the interface ports of the.....
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03
January 17, 2020 / Interview
Membrane Switch Backlighting Solutions
The membrane switch with backligting is very important for the dark environment application......
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03
January 17, 2020 / Interview
Membrane Switch with Optical Solutions
Most of time the membrane switchhes are not exist solely. Especially for those with display windows.......
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03
January 17, 2020 / Interview
Membrane Switch ESD Shield Solutions
Membrane switch's application environment is diversity. In some special areas there is strong.......
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03
January 17, 2020 / Interview
Rubber Keypad Switch Subassemblies
For some clients, they want their keypad buttons top surface look like a crystal. This need use the epoxy.....
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Concrete Applications
These are not a list of final applications for thin film switches. lt just represents some of the common uses we have.
How to install the membrane switch to your device? The incorrect installation or assembly method will possibily damage the membrane switch or reduce its life.
It may also produce potential complains from the end users in thefuture. So, the correct install method is very important. If you are the first time to use the membrane switch, try to make training in advance. LuphiTouch made a membrane switch installation guide for your worker's' raining before you manufacturing your products and you can download the MSIG at right side here.
This installation guide is just a kind of general guide based on the normal installation. If the installation surface of your product is special, you can use our guide as reference and find a more suitable installation method matter-of-factly.
Of course you also can feel free to call us or e-mails us for help! Our team is always ready for you!