Connector / Tail Finishing
If your application calls for performance in extreme conditions or reliable performance over millions of cycles, a Piezo Touch Switch may be the answer.
How a Piezo Switch Works
Finger pressure on the surface of the housing causes the housing to flex very slightly (approx. 2 microns). Pressure activates a piezo crystal which emits low level a signal which is amplified by electronics built into the housing.
|Advantages of Piezo Switches
|Material Options for Piezo Switches
Silicon (Rubber) Keypad
Silicone Keypads can provide a much different tactile experience and an enhanced perception of quality.
They can be made with or without a conductor under the keys. They provide a positive sense of interaction between the user and the device that cannot always be achieved with a flat or embossed membrane switch. They can also enhance the perception of quality in the device.
The underlying circuitry of the switch can be handled with either a PCB or flexible circuit. Some of the options available include:
- Silicone Molded
- Polyurethane or Parylene Coating
- Laser Etching
- Epoxy Coating
- Copper, Silver or PCB circuitry
- Embedded LED, Fibre Optic or Electro-luminescent backlighting
Capacitive Switches (Keypads)
Capacitance Switches represent the future of the human-electronic interface in many applications.
Capacitance Switches take advantage of the body’s natural electrostatic field. When the user’s finger touches the screen, the conductive element of the screen interacts with the electrostatic properties of the user’s body to dynamically form a capacitor. The location of the touch can be determined by one of several technologies. The touch location is then transferred to a computer either connected to, or built into the device which interprets the contact.
Sensing the Touch
The capacitive touchscreen panel uses an insulator such as glass coated with a transparent conductive material like indium tin oxide. This technology has its limitations but works quite well in applications like industrial controls and kiosks.
Projected Capacitive Touch
PCT is a more sophisticated technology implemented to allow the interpretation of multiple touch points and more accurate location recognition. In Projected Capacitive Touch, an XY array is created by etching a layer to form a grid pattern or by etching 2 discrete perpendicular layers of conductive material. Applying a small voltage to the grid creates a grid of capacitors. When a person’s finger comes close to this grid the capacitance changes at that precise point on the grid. This type of technology also permits multi-touch sensing.
Other technologies such as Mutual Capacitance Screen and Self Capacitance Screen have been implemented in Apple’s iPhone. Mutual Capacitance uses two discrete layers; one layer is the driving layer with lines that carry current and the second layer is perpendicular sensing lines which sense the changes in current at nodes created by the grid. Self Capacitance works with a single layer consisting of a grid of discrete electrodes connected to capacitance sensing circuitry.