Top 10 Projected Capacitive Highlights
- Wear resistant
- Works with water
- Exceptional optics
- High-resolution abilities
- Touch coordinates are drift free
- Operates in environmental extremes
- Multi-touch capable – up to 10 fingers
- Works with finger, gloves and any pointing device
- Plastic versions are light-weight and break-resistant
- Flexible sensors can be contoured to curved surfaces
Mutual capacitance is now the more common projected capacitive approach and makes use of the fact that most conductive objects are able to hold a charge if they are very close together. If another conductive object, in this case, a finger, bridges the gap, the charge field is interrupted and detected by the microcontroller.
Top 5 Resistive Highlights
- Low-cost solution
- Multi-touch capable
- Low power consumption
- Liquids do not affect touchscreen performance
- Works with finger, gloves and any pointing device
Disadvantages
- Requires periodic recalibration
- Less durable than other touch technologies
- Lower transmittance and overall optical quality
The resistive touchscreen consists of a glass layer with a conductive coating on top and a polyester top sheet with a conductive coating on the bottom. The conductive surfaces are held apart by “spacer dots”, usually glass beads that are silk-screened onto the coated glass. On a 5-wire resistive design (the most commonly used kind of resistive screen in large format POS applications), a voltage is applied to the 4 corners of the glass layer. When a person presses on the top sheet, its conductive side comes in contact with the conductive side of the glass, effectively closing a circuit (this is called pressure sensing). The voltage at the point of contact is read from a wire connected to the top sheet.
