For more than 20 years, we have been offering our customers individually designed membrane keyboards and decorative foils for a wide range of industries and applications. In doing so, we provide comprehensive advice on your specific requirements in terms of equipment and technical features and actively support you in the design process.
Thanks to an enormous variety of design options, membrane keyboards are used in almost all types of electronic devices. Their ergonomic and design possibilities are virtually unlimited. Membrane switches are used, for example, where resistance to dirt and water as well as easy cleaning are required. They are also ideal for applications where a compact design or a small quantity is desired due to comparatively low tooling costs.
Suitable housing?
Furthermore, we offer not only a high-quality membrane keypad as an input element, but also all matching components such as a tailor-made housing, cable assembly perfectly matched to your requirements and the necessary evaluation electronics. Our extensive range of products enables us to supply you with everything from a single source. We attach great importance to careful planning and implementation in order to achieve the best possible result. In this way, we can ensure that all components are perfectly coordinated and function smoothly in your project. Rely on our many years of experience and know-how to implement your individual requirements in the best possible way.
Also for small quantities and development samples
For flexible and fast production of membrane keypads, we offer the option of tool-free laser cutting in addition to the established die-cutting process. With this method, short-term requirements, functional development samples and smaller special series can be implemented quickly and cost-effectively. Individualized printing of existing variants is also possible without any problems. The elimination of punching and printing tools significantly shortens delivery times. Near-series components can reach the customer within just three weeks. Laser cutting thus perfectly complements the standard process for medium and large series production.
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Advantages of membrane keyboards
- Low thickness and weight: Membrane keypads are very flat and have a low height. This allows them to be used in devices and applications where lack of space is a problem.
- Integration: Easy integration of LEDs, signal transmitters, sliders, controllers, rotary encoders and viewing windows for combination with displays.
- Customized tactility: Different technologies can be used to achieve the one desired tactility.
- Design options: Printing on the back of the foil for abrasion-resistant, customized design. In addition, buttons can be customized and labeled for ease of use.
- Easy cleaning: Membrane keypads are easy to clean because they have no gaps between the buttons where dirt and dust can accumulate. The user interface is completely enclosed. In addition, they are resistant to chemicals (solvents).
- Durability: Membrane keypads are very durable due to their construction. Their service life is at least > 1 million switching cycles. They are less susceptible to wear and damage than conventional keyboards with mechanical switches.
- Low noise: Membrane keyboards are generally quieter than mechanical keyboards. They produce only a soft click when pressed or are completely silent, such as key embossing.
- Ease of customization: Membrane keyboards can be easily customized to meet the specific needs and requirements of an application.
- EMC shielding: For applications that are exposed to electromagnetic interference or that can generate electromagnetic interference themselves.
- Low cost: Membrane keyboards are generally less expensive than traditional mechanical keyboards.
These advantages make membrane keyboards a popular choice for many applications, including computer peripherals, home appliances, medical equipment and industrial applications.
Membrane switch for a machine control
Construction of a membrane switch
The basic structure of a membrane keypad consists of five basic parts: Decorative foil, upper and lower switching foil, spacer foil and adhesive foil.
Decor foil
The decorative foil forms the top layer of the keypad and is printed on the reverse side to provide the highest possible protection against abrasion. This foil can also be embossed to facilitate operator guidance. Instead of a polyester foil, a silicone mat or other material can also be used.
Switching foil
The functional elements of a membrane keypad are the lower switching foil with the conductor tracks, switching points and terminal lug, and the upper switching foil with the contact surfaces. The upper switching foil can be replaced by metal snap-on discs or the contact areas can be printed directly onto the decorative foil. It is also possible to dispense with the upper switching foil. Optionally, polyimide (Kapton) can also be used as the material for the lower switching foil instead of polyester.
Spacer foil
The insulating foil separates the upper and lower switching foils. Corresponding recesses are provided on the contact surfaces. In the versions with metal snap domes, the spacer foil serves as a spacer and gives the metal snap disk the necessary space for actuation.
Tactility of a membrane switch
Metal dome
Metal snap domes can be used for concise tactility and higher actuation forces. When the metal snap disc is actuated, it presses down and establishes contact between two conductive tracks.
Metal snap domes have different sizes and shapes. For illuminated membrane switches, snap domes with a central recess are used. The LED is placed directly under the recess. The actuating force of a snap disc is 40g – 700g, depending on the model, and the service life is up to 10 million cycles.
Embossing
By individually embossing the keys, not only an attractive appearance but also better finger guidance and tactile feedback can be achieved. The dome embossing enables tactile feedback without metal snap domes. In addition to round keys, this embossing is also suitable for square keys. Alternatively, terraced embossing for small keys or frame embossing with a raised edge around the key surface can also be used.
Protection of a membrane switch
EMC protection
Reliable and interference-free operation of input devices is crucial in many industries, especially in medical technology. Especially when using several electrical devices in one place, insufficient shielding against electrical or electromagnetic effects can lead to malfunctions and interference. A membrane keypad with EMC shielding prevents this by means of an aluminum- or copper-coated polyester foil that is integrated into the keypad and ensures full-surface shielding. This effect not only avoids the intrusion of unwanted signals, but also interference in its own electromagnetic environment. If the keyboard has integrated displays, segmented EMC shielding of the keyboard and conductor tracks is used.
IP protection classes
Peripheral seals prevent moisture from entering, which protects the membrane keypad from short circuits. With this protection, the membrane keypad can achieve a protection rating of up to IP67, making it ideal for use in humid or dusty environments.
Membrane keypad equipment
Membrane keypads can be equipped with various features to ensure optimum operation and user-friendliness.
Membrane keypad lighting options
LEDs
Membrane switches can be easily backlit by integrating an LED switching foil or a switching foil with built-in LEDs. Special adhesives and sealing materials ensure LED functionality even in demanding environments with strong vibrations.
LGF (Light Guide Film)
LGF technology uses LEDs on the edge of a highly refractive film that is only 0.1 to 0.2mm thick. Unlike conventional lighting technologies such as LEDs, which must be placed on each key to provide uniform illumination, LGF technology can achieve complete and uniform illumination of the entire keyboard with only a few light sources. This makes LGF technology particularly advantageous for use in devices with limited space and compact designs. Each key can be backlit in different colors. At the same time, the flat design and flexibility of the membrane keypad are retained.
LGF technology allows not only uniform illumination of the keyboard, but also the use of special effects such as the disappearing effect. This is lettering that is invisible when unlit and only appears when illuminated. Unique designs and visual effects can be achieved with this technique.
Rotary encoders / signal transmitters / capacitive control
Thanks to Duraswitch technology, rotary encoders and cursor controls can be seamlessly integrated into membrane keypads. Compared to separate solutions, integration is much more cost-effective as wiring and soldering processes are eliminated. In addition, very flat piezo buzzers can be integrated into membrane keypads, resulting in a more compact and space-saving design.
Integrated Touch Panel & Windows
An effective and economical combination of modern display and proven keyboard technology allows the advantages of both worlds to be utilized. There are various options for integrating displays into membrane keyboards. Simple variants include punching out the display area or integrating a viewing window. These can be specified individually in designs such as glossy, matte, anti-reflective, scratch-resistant, UV-resistant and colored. If a touch panel is present under the viewing window, a highly transparent adhesive layer with a light transmission level > 99% is used to avoid the formation of Newtonian rings. Bonding takes place in a clean room.
Carrier Plate
For reinforcement, the membrane keypad can be mounted on customized support plates. Aluminum plates are used as standard, if necessary with press-in bolts for easy mounting. The membrane keypad is glued onto the carrier plate over its entire surface. A complete assembly with display and printed circuit board is also possible. Depending on the installation situation, seals can also be integrated directly.
Membrane keypad design options
Silk Screen & Digital Printing
Membrane keypads are always printed on the reverse side. This provides a special longevity of the printing, as the print is protected from abrasion and wear. The common methods are:
Screen printing: this method is often used in the production of membrane keyboards. Here, the lettering is printed on the keys by applying the ink to the foil through a screen. Screen printing is a cost-effective method for producing membrane switches with high durability and resistance.
Digital printing: This method is particularly well suited for printing color gradients and photo-realistic graphics, and allows for greater flexibility in the design of membrane switches. Digital printing is particularly well suited for prototypes, one-offs and small batches, as it eliminates the cost of creating screens.
Silicone keys / rubber design
The membrane keyboard with silicone keys offers a non-slip key surface and conveys the feeling of a high-quality keyboard. The key shape can be realized in various geometries. Alternatively, the full surface of the decorative foil can be replaced by a silicone layer to allow for protruding keys with free shaping, guide elements such as offset rings around a key, Braille lettering or cursor keys. These rugged and durable membrane keyboards with silicone covers are often used in industrial applications and are easy to clean. In addition, they can be customized with different surface coatings to meet the requirements of each application.
Epoxy Coatings
Epoxy finishing is a particularly effective method of creating three-dimensional keys. Here, instead of the usual embossing of the foil, an epoxy material is applied to the surface of the key, which creates a particularly noble and glossy surface due to its high transparency. This finishing method gives the keys a raised appearance and ensures a pleasant feel. Thanks to epoxy finishing, not only round but also other contours and shapes can be realized. The design possibilities are almost unlimited and can be tailored to the customer’s individual requirements. Such a keyboard is usually perceived as aesthetically pleasing and very high quality and can thus contribute to increasing the value of the product.
Surface structures of membrane keypads
Membrane keyboards are extremely versatile input options that can take on a wide range of surface textures. The options range from classic high gloss to a soft silk matte finish. In addition, membrane keyboards can also use specially embossed foils to create metal-look effects, for example. By using such special foils, an extremely realistic representation of the metal structure is achieved, creating an aesthetically pleasing and high-quality impression.