How Does a Touchscreen Work? Technology Behind Touchscreens Explained

Working of Resistive Touchscreen

In a resistive touchscreen, there will be 2 layers of electric current running through both of them.

The outer membrane will be made up of plastic and the inner part will be made up of glass substrate.

Both of them will be covered with a metal coating to make them conduct electricity.

Generally, Indium Tin Oxide is used for coating. The layers are separated by spacers which are made up of insulators.

When your finger touches the screen, the pressure will cause the 2 layers to touch each other, changing the voltage at that point and the processor that is connected to the screen will calculate the x and y coordinates.

The resistive touchscreen is generally used in ATMs and supermarkets. One of the main disadvantages of this type is that it cannot handle multiple touches at a time.

That is why, most of the high-end devices like tablets, smartphones use capacitive touchscreens which we will be discussing in the next section.

In capacitive touchscreens, a layer of capacitive material is used to hold electric charge, and while you touch the screen, the amount of the charge at the point will vary.

They are further divided into 2 types — surface and projected touchscreens. First, let’s look at the surface capacitive touch screen.

Surface Capacitive Touchscreen:

Working of Surface Capacitive Touchscreen

A transparent electrode layer will be present at the top of the glass panel and then it will be covered by a protective layer. The 4 electrodes which are placed at each corner of the screen maintain a level voltage over the entire conductive layer.

When your finger comes in contact, then the charge will be distorted. The sensors which are present on the sides of the screen will detect the change in the charge at the point and thereby detect its location.

Unlike a resistive touchscreen, this works only with humans/ styluses. One of its main disadvantages is that the screen is highly sensitive to electromagnetic interference and similar to a resistive touchscreen, these do not support multiple touches at a time.

Now let’s look at the next part — Projected Capacitive Touchscreen.

Projected Capacitive Touchscreen:

Working of Projected Capacitive Touchscreen

This makes multi-touch features in our smartphones possible. They are generally chosen over a surface capacitive touch screen due to their durability and multi-touch functionality.

On the vertical side of the screen, there will be driving lines carrying current. Horizontally, there will be sensing lines detecting current. A specific electrostatic field will be registered as a baseline by the processor.

When you touch the screen, the field will be distorted and the processor will detect the location where there is a change in capacitance value.

The thinner the grids on the touchscreen, the more accurate the response will be.

Thanks for reading through the article. If you like the article, do give it a like and follow us for more content like this.

From - https://vocal.media/01/how-does-touchscreen-works