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Modern Trends and Working of Capacitive Interface and Screens Touch Keypads

Modern Trends and Working of Capacitive Interface and Screens Touch Keypads

Aug 16, 2021

Capacitive Interface
Already there is no doubt that the capacitive interface is   very important part of life today. They increasingly replace physical buttons and increase the practicality of most technological equipment. From ATMs to smartphones that we use all the time, we can say that almost everything that involves technology is just a touch away.

This touch is even faster and more responsive, bringing even more simplicity to use. Basically, we have two main types of touch keypads: resistive and capacitive. Both work with touch sensitivity, of course, but often have different applications in practice.

Resistive screens and their composition

Resistive screens are commonly common in ATMs, and in less portable equipment.  This type of screen is simpler and usually has a longer lifespan than others. However, in comparison to capacitive interface, they are slightly less responsive than capacitive ones, and work with less precision.

Between the two layers of resistive screen, passes a constant electric current that “fills in” the space between them. When this type screen is pressed current is interrupted, and the software can identify that action as a touch.

Why electric current is needed in layers and how it works?

You may have already noticed that in the case of bank tellers, for example, it is necessary to exert a little more force on the screen for it to identify the touch. In Capacitive Interface, this is exactly because it is necessary to break the electric current that divides the layers for the screen to identify the action in a certain place.

One downside to these screens is that they don’t work well in high light. They are often darker than smart phone screens, for example. Also, they can only identify one touch at a time, so it’s not possible to zoom in or perform very complex actions.

 What is capacitive touch? 

Capacitive touch is a touch screen technology based on the operation of electrical charges on the human hand or materials and objects containing electrical charges when touching the device screen.

In Capacitive interface thanks to the principle of operation of electric charge that people can now completely control the information processing system. Inside the smart device easily without the need for a mouse.

Types of Capacitive touch

Currently Capacitive touch is divided into single-point capacitive touch and multi-point capacitive touch:

  • Single point capacitive touch: Smart device only supports receiving information from only one point.
  • Multi-point capacitive touch: The smart device supports receiving information from multiple points.

 Structure and working principle of capacitive touch

The capacitive touch screen is composed of insulating sheet and superimposed by a transparent conductor plate. In addition, the Capacitive Touch Layer of Capacitive Interface is also equipped with a Metal ion-coated glass that increases the visibility of light up to 90%.

When a human finger touches the screen, the conductive plates will attract positive and negative charges from the human body. Creating; a change in capacitance. At this time, the system software of smart devices will analyze and decode information about the change of capacitance.

Coordinate’s determination of interfaces

Determine the exact coordinates at the point that the human finger touches. Execute control commands according to human finger operation.  In today’s technology era, the world’s leading Technology manufacturers.

In this matter, typically Apple technology, have developed capacitive touch screen panels (Capacitive Interface) that become more sensitive and thinner. This makes the user feel more directly in touch with the information displayed, and the thinner screen also increases touch sensitivity.

 Advantages of capacitive touch screen 
  • Sensitive capacitive touch screen, faster response.
  • Bring good brightness to the display.
  • Develop more anti-dust and anti-scratch systems.
  • Long screen life presence.

 Disadvantages of capacitive touch screen 

Following are the few disadvantages of capacitive touch screen.

  • Expensive price
  • Due to the principle of operation based on the change of electric charge, insulating items will tend to seem insensitive (pen, towel,).
  • The touch screen easily affect and untouchable in wet environments or inclement weather.

How touch keypads work in Capacitive Interface?

Capacitive Screens

Capacitive touch keypads are present in most smartphones and have a much faster and more accurate response to touch. This type of screen has two variations: projective and surface. In the case of projective, they have sensors all over the screen, while surface ones only have sensors in the corners.
Capacitive Interface 2021

However, in general, capacitive screens work from pressure drop. As soon as we touch the screen, the electrical current in its top layer transfers some charge to our hand. In this way, the software identifies this loss and understands it as a touch on the screen. The input which is taken here is nothing else, but the electrical properties of human bodies.  It will create desired output

The interface methodologies in Screens (Capacitive Interface)

In case you’re wondering if we shouldn’t, then, feel this charge leaving the screen straight to our fingers, calm down. This current is quite small and cannot be perceived by us. But knowing that explains, for example, why it’s not possible to use cell phone screens with gloves or pens.

When you try using an object, the electric current is not attracted at that time. Hence, the touch does not work in this case. In the case of wet screens, it is exactly the opposite. Further, water is a much better electrical conductor than our body.

Working of Capacitive screen

Figure below illustrates the working of capacitive screen in clear way, helping you in its better understanding.


Capacitive screens also called Capacitive Interface are common on smartphones and record more than one movement at a time, which makes it possible to zoom in on photos or images.

The advantage of these screens is that they are the exact opposite of resistive ones. In addition to working well in bright environments, it is still possible to perform various actions with different types of touch.

Other touch keypads apart from capacitive screens

It is Capacitive Interface These displays are quite common in e-readers. For example, another touch keypad technology is surface acoustic waves.

As the name makes clear, the device emits acoustic waves on the screen that are imperceptible to human ears, but which identify when an object or finger touches the screen. Finally, the “near field imaging” technology has very common military use and recognizes the touch of the screen by different objects through the device’s electric field.

An outlook on capacitive technology

As soon as something touches the display, this technology can notice the change in the field and classify it as a touch. Capacitive Interface is a technology; that has completely changed the world of human-machine interfaces.

Until a few years ago the reference to activate any command was represented by a key. It could have a long actuation stroke, it was plastic, rubber, membrane, simply a mechanical switch. Today, with the advent of capacitive technology, and Capacitive Interface; all this is no longer there. Just touch a smooth surface like glass and the “touch” immediately realizes the desired input.

Research and development in Capacitive keyboards.

Investing in research and development to be able to quickly offer the capacitive keyboards that are the object of the desire of new designers. Capacitive sensors are the part necessary for the proper functioning of a capacitive keyboard and are mostly unknown to our customers’ designers who almost always focus on the use of the microcontroller and its operating firmware.

As with all new technologies, the path at the beginning proved difficult and complex in terms of Capacitive Interface. Not only for the purely electronic part that capacitive devices need, but above all for the realization of capacitive sensors. The capacitive sensor is that flexible circuit which, applied to the “cover lance” and connected to the electronic board.

Role of microcontroller and its functionality

It is where the microcontroller resides, transmits the difference in the electric field existing now of the touch. Thus, making the microcontroller the signal to interpret the command of the key. So, as you can imagine, the capacitive sensor has a fundamental importance for the proper functioning of the keyboard.

Since many capacitive keyboards are backlit to increase their charm. Aesthetics, as well as to allow the user to understand that the keyboard has perceived the command.

How famous transparent conductive inks formed?

This is, how was born, the famous transparent conductive inks. At the beginning these inks have given many problems as some manufacturers have placed on the market these new products not yet ready to be common and transformed by screen printing companies.

How the designers in study capacitive sensors

A certain type of light and environmental pollution, deteriorate very easily and need special storage as well as having a very short shelf life. It is from these experiences that our designers study the capacitive sensors and as with all new technologies, the path at the beginning proved difficult and complex in terms of Capacitive Interface for our customers’ keyboards, working on the circuit layout.

On the front panel graphics (cover lance) to be able to use absolutely guaranteed silver based inks.


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