Touch panels can be fitted to pretty much any display product imaginable. They completely change the way a user interfaces with a device by combining the viewing and interactive area into one plane. There are two main types of touch panel to consider when planning an application, these are the resistive touch panel and the capacitive touch panel.
These touch panels have multi-touch ability and are extremely durable in most environments including withstanding water contact, dust and grease. Capacitive touch panels will activate with either a bare finger or a capacitive stylus and have excellent dragging performance. Capacitive touch panels come with a built-in I2C interface controller. This allows for quick time to market while keeping development costs low.
As capacitive screens don't need much contact at all, you can swipe across them very lightly and get just as good a response as you would with a slow, heavy drag. Capacitive Touch Panels are made of an insulator that is coated with a transparent conductor. Typically, Capacitive Touch Panels consist of glass as the insulator coated in indium tin oxide (ITO). The human body is also an electrical conductor, so when the human body comes into contact with the Capacitive Touch Panel, the touch panel's electrostatic field becomes distorted. It is this distortion that is then read by the touch panel controller and, depending on the program written, the display will respond accordingly.
Resistive touch panels are designed to allow items other than your finger to activate the touch. Resistive touch panels don't rely on organic properties of your finger so you have more options to interact with them. Resistive technology senses pressure which is why a gloved hand will work, but it requires harder contact so a stylus responds more accurately. Resistive touch screens are great for handwriting recognition with a stylus.
The resistive touch panel is made up of several layers. When you press down onto the touch panel with your finger or stylus, the top layer flexes and pushes back onto a layer behind it. This will effectively complete a circuit and tell the controller which part of the touch panel is being pressed.
Resistive Touch Panel Integration Guide
This document is intended to provide guidance and cautions related to integrating an Analog Resistive Touch Screen into an enclosure. The topics and suggestions contained within this document are taken from years of experience working with touch screens. Remember, each situation is different and you may need to adjust some of the following suggestions to best fit your particular application and environment.
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