We manufacture Membrane switches/keypads for data input, for example for data signals, specific to customers needs and applications. They compose several single functional layers, have extensive and flexible design possibilities and are therefore found in every type of electrical equipment. We offer a wide range with or without tactile feedback and diverse options on windows, screening and lighting.For Membrane Switches, Overlays and Decor Foils we also offer Digital as well as Silk Screen Printing. Digital Printing is preferred for colour gradients as Silk Screening has a restricting effect on gradients.
Digital Printing is well-suited for prototype, one-off and small series productions as no screen set-ups are necessary. This reduces costs and delivery time is one week less. Hybrid Printing, a combination of Digital and Silk Screen Printing is also available.
A keypad consisting of a plurality of individual layers which are superposed on each other and thereby give the overall structure of the membrane keyboard. By default, there is a membrane keyboard from 4 basic parts: decorative foil, upper & lower switching foil and a spacer film.As a top layer of the keyboard, there is a decorative film of polyester or polycarbonate and is to ensure the highest possible protection against abrasion, printed on the back. For applications in the medical field and areas with high hygienic requirements, the front foil can be equipped with an antibacterial coating. Also UV-resistant polyester for outdoor use is possible.
Functional elements of the keypad are the lower circuit film with the conductor tracks, the switching points and the terminal lug disposed thereon and the upper circuit film with the contact surfaces, which are opposed to the switch points on the lower film. On the upper switch membrane may not be necessary under certain circumstances, if it is replaced by metal domes, or the contact surfaces is printed directly on the decorative sheet.
For special applications and complex circuits the lower switching film of polyimide (Kapton) is implemented instead of polyester. A hard circuit board of FR4 is suitable for the circuit configuration and also acts as a support plate, if appropriate with grub screws or bushings for mounting. The spacer film as an insulator separates the upper and lower switching film. In an embodiment with metal domes it comes to the task of fixing film.
Membrane Switches according to IS0 13485
Various selective measures undertaken by N&H Technology have optimized the production of membrane switches at our suppliers in China in order to conform with the Quality Management Standards IS0 13485 and thus to meet all requirements of our customers in Europe. Our customers have responded positively to this.
Membrane Switches with Integrated Rotary Encoders
Relatively new in our programme are Rotary Encoders integrated in Membrane Switches. Rotary Encoders with 2-Bit-Gray-Code and 2-Bit-Code and also analogue Potentiometers can be built into Membrane Switches. Rotary Encoders have a lifespan of approx. 500.000 rotations whilst an analogue Potentiometer only obtains an average of 100.000. Our Chinese production plants produce integrated encoders using the patented process developed by the company Duraswitch. There is no wiring and soldering as with separate encoders and therefore it provides a substantial save on assembly time and costs.