Resistive touchscreens are different than capacitive touchscreens in that a single touch on the screen compresses the flexible top layer into contact with the bottom glass layer. Resistive touchscreens have two thin layers with a thin gap in between the layers. The top layer is typically made up of clear material while the bottom layer is made up of rigid material. In contrast to PCAP touchscreens, resistive touchscreens can be activated by anything.
(1) 4-Wire Analog
In a 4-wire analog setup, both the top and bottom layers contain two electrodes. These electrodes are positioned perpendicular to one another. Electrodes on the top layer are the positive and negative Y axis, while electrodes on the bottom are the positive and negative X axis. The layer between both the glass and film improve the durability of the product to withstand various types of environments.
(2) 5-Wire Analog
A 5-wire analog setup consists of four electrodes placed at each corner of the bottom layer. There are four wires that connect these electrodes together. The fifth wire is the “sensing wire” embedded into the top layer. Because the top layer is working only as a pick-up layer, it can tolerate resistive changes without impacting the reliability of the touch points’ accuracy from the base layer. For this exact reason, the 5-wire is able to withstand temperature, humidity, and mechanical environments.
(3) 8-Wire Analog
The most sensitive resistive screen design is that of the 8-wire sensing circuit. The layout is similar to the 4-wire analog, but each of the bar electrodes contains two wires. This introduces some redundancy into the circuit because even if one of the wire pairs loses resistance over time, the second wire provides a secondary signal to the processor. For applications where accuracy is critical and recalibration is unacceptable, the 8-wire resistive touch screen is the preferred solution.
Electromagnetic Interference (EMI) is a measure of a device’s ability to operate as intended in an environment without disruption. PCAP is most susceptible to EMI while resistive is less susceptible. The TG3 engineering team has the ability to help advise the customer for the best solution that’s needed.
Force sensors can be used in touch devices. At the core of force sensors are load cells which are transducers that convert force into measurable electrical outputs. TG3 utilizes force sensors in new technologies to triangulate location. This capability can solve additional shortcomings in other technologies.