The membrane switch is a momemtary switching device that is manufactured by using a series of flexible layers of polymer films and adhesives.
The top layer, called a graphic overlay, is manufactrued by printing on the down surface of transparent polyester or polycarbonate film.
Membranes switches can be constructed of multiple circuit layers, and more optimized graphic design features, such as domed key embossing.
Designs that are more conplex require more material layers for proper construction and reliable operation.
Membrane switches, when combined with components such as a tactile dome, graphic overlay, or integrated LEDs or resistors can provide the designer with virtually limitless capabilies to create the ideal custom user interface for their products.
Metal dome membrane switch:
Manufactured from nickel plated stainless steel, metal dome switches are momentary switch contacts that become normally-open tactile switches when used in conjunction with a printed circuit board, flex circuit, or printed membrane circuit. Tactile metal dome switches provide an extremely reliable user interface and are installed through a pocket design concept, or directly on printed circuit boards with pressure-sensitive adhesive tape or dome cover.
Tactile vs. Non-tactile membrane switch:
Circuit boards typically rely on membrane switches to turn parts of the device off and on.
There are two main membrane switches in use today on printed circuit boards.
One is referred to as a tactile membrane switch, and the other is called a non-tactile membrane switch.
Each switch performs a different function on the printed circuit board.
Tactile membrane switches are commonly made with stainless steel, polydome, or a hydro-form domed overlay, and can be activated up to a million times.
Tactile switches are internally vented and are sealed off from the surrounding environment. This helps prevent contamination of the switch from outside particles.
A non-tactile switch works the same as a tactile except there is no physical response when pressed. In a non-tactile switch,
the bottom side of the overlay is printed with conductive pad.
When the overlay is pushed down the conductive pad connects to the conductive footprint on the silver printed circuit layer.
Flat membrane switch:
Flat-panel membrane keypads are typically designed with three layers.
The upper layer features the printed on the front and electrical conductive stripes printed on the back.
The middle layer is a spacer, meaning its sole purpose is to prevent the upper and bottom layers from touching.
On the back of this layer is another set of conductive stripes, which are typically printed perpendicular to the stripes on the upper layer.
When a user presses a key, the stripes connect to form a grid. Subsequently, this allows the human machine interface (HMI) or device to register the keypress.
FCB mambrane switch：
A PCB membrane switch, as the name suggests, is an electrical switch that’s characterized by the use of a printed circuit as well as a flexible construction.
They feature a printed circuit board made of copper-covered cloth or resin-infused fiber.
In high-precision applications, gold may be used to ensure reliability with the PCB membrane switch. Regardless,
all PCB membrane switches feature a printed circuit as well as a flexible design.
LED membrane switch：
LEDs are used primarily as indicator lights, and are a popular, low-cost, point-source lighting method.
Embedded LED’s emit very little heat, and come in a variety of colors including red, yellow, green, blue, white, and bi-color lamp packages.
Surface mount LEDs can be bonded into our polyester switch constructions, which provide a reliable, cost effective light source.
FPC membrane switch：
The difference between FPC membrane switch and ordinary membrane switch is that the circuit is no longer a silver paste printed circuit,
but a more stable FPC circuit material, which is more resistant to high temperature and corrosion.
FPC membrane switch circuit layer uses FPC flexible circuit board, the circuit has high precision,
output spacing of 1.0mm, extremely low resistance value, stable and reliable performance, and long service life.