How does the touch screen work?

touch screen

The use of smart phones and tablets has spread in this era, and they have become an essential and vital part of our daily lives. Many of us wonder about how touch screens work, how the phone responds and executes the required command when touching a specific place on the screen, so we will present in a simple and clear way how touch screens work.

We can define the touch screen as the transparent layer that is located above the display screen in smartphones and tablets, where hand movements or writing with the pen of the device are sensed.

touch screen components

• The top layer is made of polyester, and this layer is coated with a transparent conductive metallic paint.
• A layer of adhesive, placed under the top layer to fix it.
• The glass layer is coated with a layer of transparent conductive metallic paint.
• A layer of adhesive on the back glass, in order to increase the volume.

Touch screen technologies

Resilience technology

The resistive touch screen consists of an acrylic or glass layer, covered by two layers, one of which is conductive layer, and the second is resistive layer, and there is an invisible separator between the two layers. The touch screen, when the screen is pressed with the finger, the conductive and resistive layers unite, allowing the passage of an electric current over the touched area, then sending signals to the processor after converting these signals from analogue to digital, after which the processor translates the digital signals or data and appears on the screen in front of us.

The advantage of resistive touch screens is that they need a touch pen (stylus), and they need to press hard on the screen to respond, and they are cheap compared to other technologies.

Capacitance technology

The screen consists of a thin layer of oxidized tin on a sheet of glass, and there are four electrodes on the screen, which are connected to vibrating electrical circuits.

When touching the screen or pressing the finger, the tin layer absorbs the charge coming out of the finger, and the electrodes transfer it to the vibrating electrical circuits, so that the signals reach the router, and it transmits them to the processor to translate the data into output. This technology is more advanced than resistive technology, and more responsive when touching the screen with a human finger.

Surface ultrasound technology

It works with surface sound wave technology, and when touching the touch screen with a finger or a pen, an electric field results, then these signals are transmitted to the control unit, then to the processor to translate this data into outputs that appear on the screen. Despite the advancement of this technology, it is affected by external factors such as pollutants that form on its surface.

infrared technology

This technology works with optical beam blocking technology, as the screen is equipped with a panel of invisible wires, with photoelectric cells, an infrared network, photodiodes and color-sensitive diodes. When you touch the screen, an electric field is formed, which sends signals to the processor and thus converts them into data that appears on the screen. Infrared technology is characterized by its high ability to withstand shock and impact.