Dear readers of Tecnogalaxy, today we will talk about Touch Screen monitors and we will see how they work in detail.


Nowadays, physical buttons have been replaced with touchscreens, which are much more efficient and practical. Touchscreens are used everywhere, in elevators, ATMs, cash registers, etc.


There are basically two categories of touchscreens:

  • resistive
  • capacitive

Today, the capacitive type is more widespread and is used in almost all new generation mobile devices, such as tablets and smartphones.

Resistive touch screens

They were the first models of touch screen made, the operation is based on the slight pressure of the screen that the user must exercise to interact with the device using the finger or any other object. It is called resistive because their operation is linked to the presence of particular electrical components called resistors.


They are more widespread today, as we said before on tablets and smartphones, their operation is based on the transmission of heat generated through the interaction of the user with the device used.

They are so called because they are based on electrical devices called capacitors, which have the task of detecting the level of temperature during interaction.

If you take a nib or another object and try to press on your Tablet you will not get anything.

Do you know how resistive touch screen works?

If we look at a resistive screen profile, we can notice that it generally consists of two main layers:

The first is a top layer called PET “polyethylene Terephthalate”, a thin layer called film, made of a very flexible material called polyethylene.

The second layer, the lower one called BG “Bottom Glass, lett”, is basically a simple layer of glass quite thick, similar to that of phone displays.


The layer called PET being flexible is the main part affected, while the Bottom Glass perceives where the pressure on the screen has occurred.

Below the PET and above the Bottom Glass are two very thin layers of a resistive substance “made from a metal compound”, called ITO.

The ITO is an important one that is present between PET and Bottom Glass, when the PET is pressed creating pressure, this pressure is captured by the first ITO layer that rejoins the second ITO layer that interacts with the Bottom Glass.

Because this substance is important… if there were no PET and BG they would not have a chance to communicate with each other.

Between these two starti we find the empty space “0.05 mm”, this space is used to make sure that they can be joined when the pressure takes place, besides this but it is necessary that the film of PET film and the ITO, return to the original position once the pressure is finished.

The space is filled in a distributed way with small nails, fixed on the second layer ITO “about 0.03 mm large”, which in jargon are called “Spacer points”.

In addition to restoring the PET layer to its original position, they also avoid deformation problems in case of too strong or uncalibrated pressures.

The conductive layer then sends a current from this contact point, while the processor in the phone uses this current to figure out the location of the point. The resistive screens are very resistant and precise…. but they are not too efficient.

This type is used in places where accuracy is a priority over speed of use, such as an ATM or cash desk.

Do you know how capacitive touch screen works?

This toipology instead uses the conductive nature of our skin, in fact these touch screens consist of a matrix of electrical circuits arranged on two similar films, but perpendicular, thinner than a human hair.

These layers have a low voltage current flowing through them, which is transferred to the tip of our fingers to the touch.

The voltage drop due to this charge loss is detected by four electrodes located at the four corners of the phone. Using voltage drop data, the processor detects the exact location of the input.

Now we understand why when we have gloves the touchscreen of our device does not work and when we have wet fingers the phone goes crazy.


did you know that?

Touch Screen technology was born in the 60s, think that high-end phones still use the basic concept developed in the 60s.

The first touch screen was patented in 1969, while the first smartphone to use it was the 1992 IBM Simon!!!!

The Touch Screen can be compared to a sandwich with several overlapping layers, depending on the type of layers you can have touch sensitive screens of resistive or capacitive type.

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