Capacitive vs Resistive Touchscreen
Touchscreen technology has invaded our mobile phones, tablet PCs, laptops and even desktop computers. Capacitive touchscreen and resistive touchscreen are two technologies used in touchscreens. The underlying principles in these two technologies are quite different and are well worth knowing. A proper understanding in these technologies is mandatory in fields such as computer hardware development, Operating system designing for computers, Mobile phone application development and many other fields. In this article, we are going to discuss what resistive touchscreen and capacitive touchscreen are, their pros and cons, how resistive touchscreens and capacitive touchscreens are built, their similarities and finally the difference between capacitive touchscreens and resistive touchscreens.
Resistive touchscreen technology is a widely used technology in developing touchscreen devices. In this technology, a matt of resistive material is laid out on the top layer, and a conducting plate is placed on the bottom layer. There is an air gap of a few microdots between the two layers. When pressure is applied on the surface, a closed circuit is formed between the top layer and the bottom layer. The place of the touch can be identified using the resistance of the vertical and the horizontal lines respectively. Since resistive touchscreens are based on the pressure of the touch sensitive surface, it does not require any special stylus or any other device to operate. However, the main problem involving resistive touchscreens is that it responds to unnecessary touches. These unnecessary touches can cause pocket dialing on mobile phones and unwanted clicks on other devices.
Capacitive touchscreens are also widely used as touchscreen devices. In this technology, a transparent conductor is coated on a transparent insulator. Most common of these conductors is Indium tin oxide. The insulator is almost always glass. When a conductor is in contact with the conduction surface of the screen, it will change the electric field of the conducting surface. The determination of the touch location is done using several methods. The surface capacitance method calculates the capacitance of the four corners of the display when a conductor is touching the conducting layer of the screen. The projected capacitance method uses a grid like conductor structure to determine the location with more accuracy than the surface capacitance. The main problem involving the capacitive touchscreen is that it requires a conductor to activate the touch sensitivity. This becomes a real hassle in the winter when the gloves are worn. There are special kinds of gloves made of conducting tips and the inbuilt stylus would also work, but both these items are not convenient. On the pro side, since this is sensitive to the conductivity, it will not pocket dial your phone.
What is the difference between Resistive Touchscreen and Capacitive Touchscreen?
• Resistive touchscreen uses the resistance of the conducting grid to get the location of the touch. The capacitive touchscreen uses the change of capacitance due to an external conductor to locate the touch.
• Resistive touchscreen is a passive technology, whereas the capacitive touchscreen is an active technology.