Membrane Switches

Compact, cost-effective, reliable and durable

Custom membrane switches and membrane keypads are flat input devices that can be easily customized to specific application requirements. Consisting of several flexible layers, membrane switches can be applied even to curved substrates (radii starting at R250). With and without tactile feedback, rigid or flexible – depending on the application, they offer the exact features needed, standing out even among the wide array of HMI options available today. 

Compact, cost-effective, and endlessly customizable, it’s no wonder they have become so popular in homes, offices, and industrial applications.

Membrane switches empower exceptional product design for the perfect HMI solution. With unrivaled durability (even self-healing after damage), flexibility, and features that please end-users (like our own GT Technology for producing attractive, resilient domed keys), our custom membrane switches can help you put the finishing touches on your exceptional product.

Hoffmann + Krippner elevates an already excellent product. Designed and manufactured according to DIN (Deutsches Institut für Normung e.V., the German Institute for Standardization) standards, our membrane switches offer world-class engineering, incorporate in-house patented technology, and have set European and worldwide standards in reliability, functionality, and design.

Request a Free Sample

See for yourself the many possible design and functionality options with a FREE backlit membrane switch sample.

Why use membrane switches or keypads?

Endless customizations to create the perfect product design

Product managers and designers need world-class parts and tools if they want to design best-in-business products. Thanks to easy and comprehensive customization options, Hoffmann + Krippner screen- and digital-printed custom membrane switches can be adapted to virtually any possible design idea, regardless of application. Custom membrane switches and keypads can:

> Be made with and without tactile feedback, and rigid or flexible
> Mounted on printed circuit board, allowing for more compact designs
> Take up less space than other input devices, leaving designers more options

Other design options include (but are not limited to):

> Illuminated keys with backlit membrane switches
> Raised (domed) keys (see GT Technology below for more information)
> Double contact switches for enhanced security

User-friendly operability for a better end-user experience

Successful products please users; and tactile feedback makes input devices easier and more pleasing to use, while simultaneously reducing information entry error rates. Our membrane switches with tactile feedback ensure clear, low-bounce switching behavior, regardless of who is using it, while the shape of the contact fields guarantees reliable contact. Further, our membrane switches:

> Facilitate optimal ergonomic operation of user interface
> Can enhance or replace tactile feedback with optical and/or acoustic signals
> Are compact and safe to operate
> Can provide a graphic overlay visible in a 180° radius
> Are easy to clean with a variety of cleaning materials, including fluids

Extended durability and exceptional working lifespan

Hoffmann + Krippner membrane switches offer over one million operations or switching cycles, in a variety of environmental conditions.

> With no moving parts, there is no mechanical wear of the contacts
> Hoffmann + Krippner uses only the most reliable parts and materials
> Some models use gold-plated electrical contact surfaces to increase longevity
> Sealable design protects against water or chemical fluid ingress into the switch area
> There is no danger of an electrostatic discharge
> Self-healing features can repair damage without user action (see below)

Excellent for hygiene-critical environments

Some applications place additional demands on the products used, and membrane switches can easily accommodate specialized applications, such as health care, food production, nuclear technology, and more.

In fact, advanced technologies in Hoffmann + Krippner membrane switches open completely new avenues for product design in these areas, including antimicrobial surface preparation (detailed further below). Additionally, due to its high voltage and frequency, EL lighting is often not permitted in medical technology, while H+K’s LED-based keypad lighting can be used freely.

Ready to get started?

Please contact us today to start developing your custom membrane switch for the ultimate man-machine interface experience.

Components and Options

Various functions can be easily supplemented with a wide range of additional components: bright backlighting, complex electronics, modern touchscreens, robust carriers or elegant domed key features.

backlit membrane switches

Assembly of a membrane switch

A membrane switch consists of several film layers and additional components that can be customized. The standard assembly of our flexible membrane switches always consists of 6 individual layers:

> Graphic overlay or decorative film
> Adhesive
> Dome retainer
> Spacer
> Circuitry or circuit board
> Adhesive

The graphic overlay is made of durable polyester that is reverse printed with a custom design. The film can be enhanced with our GT technology or various embossing forms.

A wide variety of adhesives in variable thicknesses and adhesive properties are selected depending on the area of application of the membrane switch.

The dome retainer holds the metal domes permanently in place. The underlying spacer optimally compensates for the height of the contact springs.

 

The circuit layer is the actual heart of the membrane switch. The entire electrical function is located on this layer: the printed conductor paths according to an individual circuit diagram, the assembled contact springs and LEDs. The printed circuits on film can also be replaced by a printed circuit board if desired.

Carrier plates or housing give membrane switches more stability and can be easily added upon request.

Graphic overlay design

Dead front design

A clean and slim design for your control panel. Some HMIs control extensive functions and are therefore equipped with many keys, symbols and LEDs.

The so-called “dead front effect” ensures a clean user interface without having to sacrifice functions. A special printing process can be used to hide non-illuminated areas on the surface and display only actively illuminated areas.

membrane switches with metal effect
membrane switches with metal effect

Graphic overlay design

Metal effect 

Membrane switches with metal effect: light, durable, elegant!
Go for more individuality with the control unit of your application. A membrane switch is lightweight, reliable, durable and with the right design, it can be transformed into a elegant control unit.

The textured and reflective film surface resembles brushed metal and blends perfectly with other metal surfaces.

Backlit membrane switches

Many machines and work stations operate in low light conditions, which mandates internally backlit membrane switches. An ingenious combination of side-LED and light diffusing panels improves upon electroluminescent film (EL film) technology to offer extensive color options, low power consumption, flat design, and long lifespan.

LED equipped backlit membrane switches by Hoffmann + Krippner are less than 3mm thick and provide a uniform, bright, long-lasting illumination. Optionally, we can achieve a full light separation between the keys and allow to separately illuminate each individual key. The use of bi-color or RGB LEDs also provides a virtually unlimited choice of colors. In combination with our GT technology, the lighting effect can be enhanced even further.

Featured Benefits

> Ideal extension to membrane switches
> Extremely flat, cold light source
> Even surface illumination of lettering on keyboard
> Wide range of brightness adjustments

backlit membrane switches
membrane switches on FR4

Membrane switches with printed circuit board

A printed circuit board serves as a carrier for the membrane switch and replaces the circuit layer on film used for a flexible assembly. It is made of epoxy FR4 material and can be used as single/ double sided or multilayer PCB. The PCB gives the keyboard assembly more stability and the possibility to add more electronic components, both front and back.

We develop custom solutions with integrated microcontrollers and direct connection to the desired interface.

 

Carrier and housing made of metal or plastic

Membrane switches can be mounted on or recessed into carrier plates and housings. Preferably, the carriers are made of aluminum, stainless steel or plastic.

Front panels can be effortlessly integrated into the front of the device or machine by attaching self-clinching fasteners or holes. Customized housings protect sensitive electronics and complete the input system.

The surface of the carrier plate or housing can also be customized to your application: bare, anodized, chromated or brushed. A milled groove for seals ensures that your device is optimally protected from dirt or liquids.

You can also find out more about carrier plates and enclosures from TES Frontdesign, a member of our HK technology network, or from our partner OKW Gehäusesysteme.

 
carrier and housing
membrane switches with domed keys

Domed keys with GT Technology

Unbeatable durability and longevity

Hoffmann + Krippner patented GT technology provides a raised key feature for membrane switches. Raised keys allow the operator to feel where the key is located and trigger its functions without having to see the otherwise flat key. As such, GT keys enable accessible products, such as safe operation by blind operators.

We use nanotechnology to create dirt-repelling overlays that protect against any kind of contamination and mechanical damage.

Furthermore, with a dome-shaped area of shiny plastic accurately positioned onto the front of the membrane switch, GT increases the readability of keys and signal or control lights, as well as the viewing angle for the keys and user interface. GT provides:

> Creative aesthetics and exclusive design possibilities, e.g. domes on company logos, displays, LEDs, etc.
> Pleasant, operator-friendly keyboard overlay with optimal haptic
> Accelerated data entry thanks to elastic key domes

Domed keys with GT Technology 

Self-Healing technology restores original shape after damage

GT technology also enables self-healing properties that can be used for large, rectangular keys for tough industrial applications. The GT material has a self-healing feature, which almost magically brings the dome back to its original shape after the key has been damaged with something like the tip of a screw driver. To learn more, please contact us and request a free sample

> Extremely high chemical and mechanical durability of keys
> Pressure points due to hard objects “heal” on their own and leave no scratch

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