A membrane switch consists of two polyester films screen printed with conductive ink to complete the circuit. A spacer in between two circuits, which is, die cut at contact points. The die-cut holes allow the touch of a finger to close the contact, completing the circuit. The circuit is broken when released. The panel posterior is laminated with an adhesive for mounting to a backer or enclosure and is terminated with a means for interfacing with the customer’s electronics.
This particular sample is just graphic overlay only, where on the overlay there is custom designed embossed dots for users with disabilities.
Membrane switch keypad - graphic overlay - custom designed emboss:
1. Environmental: (1) Operating Temperature: -40°Cto+80°C (-40°to176°F) (2) Storage Temperature: -40°Cto+85°C (-40°to185°F)
2. Humidity: 40°C, 90% to 95% for 240 hours.
3. Vibration: 20 G’smax.
4. Mechanical: Actuation force: non-tactile 60g to 300g (2 oz to 10oz) / tactile 150g to 400g (6 oz to 14oz).
5. Switch stroke: Life expectancy: (1) Non-tactile 0.1 to 0.5mm. (2) Tactile 0.6 to 1.5mm. (3) Non-tactile > 5millionactuations. (4) Tactile > 1million actuations.
6. Electrical: (1) Operating voltage: 35volts maximum Operating current: 10 micro amps to 100 milliamps, resistive. (2) Operating power: 1 watt maximum.
7. Circuit resistance: 10ohms to 500ohms, dependent on size and layout.
8. Insulation resistance: 100Mohms at 100VDC.
9. Dielectric withstand: >250VRMs(50-60Hz1minute).
10. Contact bounce ≦ 5milliseconds.