How do touch screens work?

How do touch screens work?

Smartphones are perhaps the most important innovation in the last two decades, especially touch-screen phones. Almost none of us can do without our smartphones, but have you ever wondered how these screens work in our phones? Well, today we are going to talk about touch screens and how they work.

Types of touch screens

Resistive Touchscreens
Configuration of resistive screens
We start with the last layer, which is made of glass and covered with a transparent material that conducts electricity mostly indium tin oxide (ITO), then we find a network of spacers between the glass layer and the next layer, these separators are non-conductive.

Then we find the last layer, which is the layer that you end up working with, and it’s made of a flexible and transparent material, often polyethylene and also covered with indium tin oxide (ITO).

The way of work

When the screen is working, a relatively weak voltage is applied in the vertical and horizontal directions. When you press your finger on the screen, the two layers touch, which causes a change in voltage, and the processor can know the location of the touch by determining the x and y coordinates.

The uses, advantages, and disadvantages of resistive screens

One of the disadvantages of this type of screen is that it does not support multi-touch as smartphone screens, and its brightness is also lower, as it allows only 75% of the light from the screen to pass through.

However, it has a longer life span, is more durable and durable, and has a lower cost.

Also, you can use anything to press that screen, whether it is connected or not, because the idea is to touch the two layers together, so it does not matter what the element is.

Therefore, you find these screens in public places such as ATM machines and in restaurants.

capacitive touch screen
The second type, which is the most popular in smartphone screens, is the capacitive touch screen

How intensive screens work

Let’s start with the last layer, which is the screen itself that emits light and is made up of millions of bright points called pixels, then the layer that receives touch, which is made up of a network of vertical columns called driving lines that supply a constant electric charge, then we find an insulating layer and then the horizontal rows called sensing lines that reveal the electric charge when rows and columns meet they form points, these points form an electrostatic field and are registered in the processor as neutral.

When you press your finger on the screen, it causes a change in the electrostatic field. Because humans are conductors of electricity, this is why capacitive screens do not work when you are wearing gloves, for example, because they are not conductive and therefore will not cause a change in the electrostatic field.

Scan columns are scanned periodically and quickly to look for changed points that are counted as a touch.

The intensive screen uses, advantages and disadvantages

As we have explained, dense screens are very accurate, can receive more than one touch at a time, and allow more than 90% of the light from the screen to pass through, making them display sharper images suitable for use in daylight.

Condensed screens are widely used in smartphones and laptops.