Analog Touch Screen

Analog Resistive (Transparent Membrane Switch)

The analog resistive touch screen is designed for “pen recognition” applications or other situations where a higher resolution is required than is practical to produce with a digital resistive touch screen. Unlike the digital screen, which relies on a matrix formed by the two switch layers, the each layer on this type of touch screen has a single conductive surface.

With an analog touch screen, one layer carries the X axis and the other carries the Y axis (Figure 2). The axes are determined by the orientation of bus bars printed on two opposite edges of each layer. Both axes must remain perfectly linear in order for the touch screen to function properly. When the two layers are placed together, it creates a single switch that’s activated no matter where you touch the screen. However, the controller can detect the location of the touch based on the voltage drop sensed in each layer at the point where they make contact.

Unlike the Digital Resistive Touchs Screen, which require a pin connector for each row and column, analog models can be attached to the controller with just a four or five-pin connector. But they also have drawbacks. For example, since the membrane layer flexes, the ITO coating may fracture, especially along the edge of the transparent area, and cause touch screen failure and/or loss of calibration. However, most analog touch-screen manufacturers claim their screens will withstand at least 1 million actuations in any particular area.

Alan Burk
editor@membraneswitchnews.com

425.889.9417