What is a touch on a phone? Touchscreen - what is it? Using and calibrating the touchscreen for your phone or tablet

To control modern gadgets, there is no longer any need to press buttons; you just need to touch the screen. This became possible thanks to the touchscreen (among experts it is simply called “touch” or “touch panel”), which has become an integral part of smartphones and tablets, including iPhones and iPads. It is not surprising that due to frequent use it often breaks down and becomes a headache for the owner of the device. If you understand what this component is and by what principles it works, you can quickly detect a malfunction and avoid awkward situations when contacting a service center.

What is a touchscreen

This term was formed from two English words - touch and screen, which literally translates as “touch screen”. The history of its appearance is long and occurred in several stages. The world's first finger-controlled display was invented and described in his scientific works by the American E. A. Johnson in 1965. Five years later, Dr. Samuel Hurst, through experiments, developed resistive touch screen, and the actual physical production of the product began only in 1973.

Currently, city residents deal with touch panels almost every day: not only smartphones and tablets are equipped with them, but also ATMs, information terminals and payment acceptance points. Touchscreen connects to display and is sensitive to any touch. It can be described as an information input device that serves to replace a keyboard.

It is important to know that the touchscreen is only part of the overall design, responsible only for the sensor. To transfer an image a display is used, which is a liquid crystal matrix. The unity of these two elements is called a display module, which is practically the main component of any high-tech device.

How the touch panel works

The principle of operation of the touchscreen is simple - any touch on it triggers some function or entails certain actions. The physical features of its operation directly depend on the type of touch panel. There are seven of them in total, but the most common today are three of them.

The cheapest to produce, resistant to dirt and temperature changes. Comprises glass panel and plastic membrane, between which insulators are located. Any pressure causes the glass to push through the micro-insulator, and the membrane and panel close. After this, a special controller reads the changes and converts them into contact coordinates. The weaknesses of this model are low light transmission, short service life and a high risk of damage if dropped.

Capacitive screen

More reliable and durable, but vulnerable to bad weather, water and pollution. It uses a special touch glass coated with resistive material. An alternating current passes through it, which is supplied by electrodes located at the corners of the screen. That is, when you touch the touchscreen, a current leak occurs, which is detected by special sensors. They register these changes and transmit them to the controller.

Surface acoustic wave sensor

One of the most complex screens. The peculiarity of its work is that in the thickness of the glass there are ultrasonic vibrations. When you press the touchscreen, the waves are absorbed and converted into an electrical signal, which is then transmitted to the controller. The advantage of this technology is its long service life, equal to at least 45 million touches. The main drawback is that the screen is extremely sensitive to dirt and electromagnetic interference.

In addition to this, there are several more types of touch panels. These include:

• Projected capacitive. On the inside of such screens there is a grid of electrodes, which, when pressed, forms a capacitor, the capacitance of which is measured by electronic sensors.
• Infrared. Along their edges there are light emitters and receivers in the IR range; when you touch the screen, part of the light is blocked and thereby the location of the click is determined.
• Tansometric. They are based on simple fixation of screen deformation, are resistant to damage and are often installed outdoors.
• Induction. Inside them there is an inductance coil and wires; when such a screen is touched with a special tool, the voltage of the existing magnetic field changes.

How to check the touchscreen

The touchpad may not work correctly either if the mobile device is physically damaged or for no apparent reason. The following factors indicate that the problem is in the sensor:

There may be several reasons for such a malfunction:

1. Display dirty. If you do not promptly wipe the sensor with special means, then during operation it will become abundantly covered with fingerprints and greasy marks, which can reduce its sensitivity.
2. Violation temperature regime. Too high or low temperatures, as well as their strong drop, are a common cause of touchscreen malfunctions.
3. Damage to the cable. It can peel off from the glass due to mechanical damage, thereby disrupting the connection between the latter and the touch coating.
4. Moisture ingress. If there is liquid inside the gadget, oxidation of the contacts may occur. Sometimes the problem can be solved with a hair dryer.
5. Crash software. In this case, you need to reflash the device; for this you will need a USB cable and the software itself.

How to replace the touchscreen on your phone yourself

Before removing the touch screen, you should turn off your smartphone, remove the battery and SIM card. It is important to remember the disassembly sequence so that you can later put the device back together without damaging the internal elements. Some models may require complete disassembly of the housing, which requires special knowledge. To replace the touch screen on your phone with your own hands, you need to prepare special equipment in advance, namely:

The process of replacing the touchscreen is as follows:

1. Take off back cover of the phone;
2. Screwdriver remove all bolts along the perimeter of the body;
3. Carefully insert the spatula between the housing fastening and pry;
4. Hairdryer warm up the glue connecting the sensor to the matrix up to a maximum temperature of 80 °C;
5. Pin to display suction cup, which will allow you to separate the touchscreen from the matrix;
6. Apply thin layer of glue and install a new touchpad;
7. Carefully press it and remove any remaining glue;
8. Reassemble the device in reverse order.

What is the difference between touchscreen and display

The display is the part of the smartphone on which the image is displayed. It is he who is the conductor of visual information and makes it accessible to the human eye. A touchscreen is a touch glass, the main purpose of which is to call a particular function. That is, he is only information input tool, but no conclusion.

If the phone is broken and cobwebs appear on it, but the screen continues to work and you can clearly see the picture, then only the sensor needs to be replaced. When the device distorts the image and shows blots, you will have to change the display, which is a more time-consuming and expensive procedure.

Every person constantly encounters a touchscreen when making calls on a smartphone or withdrawing money from an ATM. Let's take a closer look at the operating features of this device.

What is touchscreen, where is the technology used?

A touchscreen is a touch screen with which the user can give commands to the device by touching it. This technology has made it possible to abandon push-button phones; now to control a mobile device you need to interact with the screen - this is convenient and practical.

The name “touchscreen” comes from two English words – touch (touch) and screen (screen). Touch screen devices are ubiquitous, and these are not only mobile phones, but also:

• tablets;
• ATMs;
• information terminals at airports and train stations;
• household appliances, etc.

Although the touchscreen has become widespread in smartphones. Regardless of the device in which the technology is used, the operating principle is always the same - you issue commands by touching the desired elements on the screen. Then the algorithm of a specific program comes into play.

The basis of any touchscreen is a liquid crystal matrix. On the back side there are diodes (they act as a backlight), on the front side there are several layers that record pressing (in resistive screens) or touch (in capacitive taps).

Resistive touchscreen is an outdated technology

There are several systems used to create touch screens. The most common are resistive and capacitive technologies, which have significant differences. You can find out more about what a touchscreen is; the website describes different systems, indicating their pros and cons.

Old smartphones had resistive screens that required the use of styluses (small pointers with which the user gave commands to the phone). The resistive system is glass coated with an elastic film and a layer that conducts electricity.

There is empty space between these two elements. The display surface is protected by a special coating that protects the screen from scratches and other mechanical damage. But for better protection, a film is provided (it came with old smartphones).

Resistive touchscreens have a number of disadvantages:

• the need to press on the screen (touching is more convenient);
• screen calibration resulting from redistribution of the mass of the insulating layer;
• rapid deterioration in the quality of the touchscreen (appearance of cracks, scratches, stains, etc.);
• short service life, which is explained precisely by the rapid appearance of damage;
• lack of sliding ability (as on modern smartphones), etc.

Today, resistive touchscreens are becoming increasingly rare. Smartphone manufacturers have abandoned them; now they are mainly used in ATMs and various terminals.

Capacitive touchscreen is the most popular system

This technology involves the use of glass with a conductive layer. Touching the display releases an electrical charge (at the location touched). Microcircuits record every touch on the display, transmitting this information to the touchscreen program.

Advantages of capacitive touchscreens:

• long service life and resistance to dirt;
• high level of transparency (at least 90%);
• better response to impact, reliability;
• excellent brightness (the picture looks clearer);
• moisture resistance, MultiTouch support.

Most often, smartphones use touch screens with protective tempered glass Gorilla Glass; it withstands light mechanical impacts, including scratches. Capacitive touchscreens began to replace their resistive counterparts in 2009.

But technology is improving, there is no doubt that in the future smartphones will be equipped with even more responsive, practical and durable displays.

What is touch glass (touchscreen)

Touch screen- an information input/output device, which is a screen that responds to touches.

Touch screen- this is a device for input and output of information through a pressure-sensitive and gesture-sensitive display. As you know, the screens of modern devices not only display images, but also allow you to interact with the device. Initially, familiar buttons were used for such interaction, then the equally famous “mouse” manipulator appeared, which significantly simplified the manipulation of information on the computer display. However, the “mouse” requires a horizontal surface to work and is not very suitable for mobile devices. This is where an addition to the regular screen comes to the rescue - Touch Screen, which is also known as Touch Panel,Touchpad, touch film. That is, in fact, the touch element is not a screen - it is an additional device installed on top of the display from the outside, protecting it and serving to enter the coordinates of touching the screen with a finger or other object.

Usage

Today, touch screens are widely used in mobile electronic devices. Initially, the touchscreen was used in the design of pocket personal computers (PDAs, PDAs), now communicators, mobile phones, players and even photo and video cameras hold the lead.

However, the technology of finger control through virtual buttons on the screen has proven to be so convenient that almost all payment terminals, many modern ATMs, electronic information kiosks and other devices used in public places are equipped with it.

Laptop with touch screen

It should also be noted that laptops, some models of which are equipped with a rotating touch screen, which gives the mobile computer not only wider functionality, but also greater flexibility in controlling it on the street and in weight.

Unfortunately, there are not many similar laptop models, popularly called “transformers,” but they do exist.

And finally, the latest mobile computer invention of mankind with a touch screen is tablet computers.

Now they are produced by almost all well-known companies. For example, Apple iPad, HTC, ASUS, Samsung and others.

In general, touch screen technology can be described as the most convenient when you need instant access to control the device without prior preparation and with amazing interactivity: controls can change each other depending on the activated function. Anyone who has ever worked with a touch device understands the above perfectly well.

Types of touch screens

In total, several types of touch displays are known today. Naturally, each of them has its own advantages and disadvantages. Let us highlight four main structures:

• Resistive
• Capacitive
• Projected capacitive

In addition to the above screens, matrix and infrared screens are used, but due to their low accuracy, their scope of application is extremely limited.

Resistive

Resistive touch panels are among the simplest devices. At its core, such a panel consists of a conductive substrate and a plastic membrane that have a certain resistance. When you press the membrane, it closes with the substrate, and the control electronics determines the resulting resistance between the edges of the substrate and the membrane, calculating the coordinates of the point of pressure.

The advantage of a resistive screen is its low cost and simplicity of design. They have excellent resistance to stains. The main advantage of resistive technology is sensitivity to any touch: you can work with your hand (including gloves), a stylus (pen) and any other hard, blunt object (for example, the upper end of a ballpoint pen or the corner of a plastic card). However, there are also quite serious disadvantages: resistive screens are sensitive to mechanical damage, such a screen is easy to scratch, so a special protective film is often additionally purchased to protect the screen. In addition, resistive panels do not work very well at low temperatures, and also have low transparency - they transmit no more than 85% of the display's luminous flux.

Using a touch pen

Application:

• PDA - (you can see touchscreens for PDAs)
• Communicators - (touchscreens for communicators)
• Cell Phones - ()
• POS terminals
• Tablet PC
• Industry (control devices)
• Medical equipment
• Car radios - ()
• GPS navigators - ()

Communicator

Capacitive

Capacitive touchscreen technology is based on the principle that a large capacitive object (in this case a person) is capable of conducting electrical current. The essence of capacitive technology is to apply an electrically conductive layer to the glass, while a weak alternating current is supplied to each of the four corners of the screen. If you touch the screen with a grounded object of large capacity (finger), current will leak. The closer the point of contact (and therefore the leakage) is to the electrodes in the corners of the screen, the greater the strength of the leakage current, which is recorded by the control electronics, which calculates the coordinates of the point of contact.

Capacitive screens are very reliable and durable, their service life is hundreds of millions of clicks, they perfectly resist pollution, but only those that do not conduct electric current. Compared to resistive ones, they are more transparent. However, the disadvantages are still the possibility of damage to the electrically conductive coating and insensitivity to touch with non-conductive objects, even with gloved hands.

Application:

• In secured premises
• Information kiosks
• Some ATMs

Projected capacitive

Projective-capacitive screens are based on measuring the capacitance of a capacitor formed between the human body and a transparent electrode on the surface of the glass, which in this case is a dielectric. Due to the fact that the electrodes are applied to the inner surface of the screen, such a screen is extremely resistant to mechanical damage, and taking into account the possibility of using thick glass, projective capacitive screens can be used in public places and on the street without any special restrictions. In addition, this type of screen recognizes pressing with a gloved finger.

These screens are quite sensitive and distinguish between finger and conductive pen presses, and some models can recognize multiple presses (multi-touch). Features of a projective capacitive screen are high transparency, durability, and immunity to most contaminants. The disadvantage of such a screen is its not very high accuracy, as well as the complexity of the electronics that process the coordinates of the press.

Apple iPhone

Application:

• Electronic kiosks on the streets
• Payment terminals
• ATMs
• Laptop touchpads
• iPod -
• iPad -
• Tablet computers

With determination of surface acoustic waves

The essence of the operation of the touch panel with the determination of surface acoustic waves is the presence of ultrasonic vibrations in the thickness of the screen. When you touch the vibrating glass, the waves are absorbed, and the point of contact is recorded by the screen sensors. The advantages of the technology include high reliability and touch recognition (unlike capacitive screens). The disadvantages are poor protection from environmental factors, so screens with surface acoustic waves cannot be used outdoors, and in addition, such screens are afraid of any contamination that blocks their operation. Rarely used.

Other, rare types of touch screens

• Optical screens. The glass is illuminated with infrared light; as a result of touching such glass, light scatters, which is detected by a sensor.
• Induction screens. Inside the screen there is a coil and a grid of sensitive wires that respond to touch by an active pen powered by electromagnetic resonance. It is logical that such screens respond to touches only with a special pen. Used in expensive graphics tablets.
• Strain gauges - react to screen deformation. Such screens have low accuracy, but are very durable.
• The infrared ray grid is one of the very first technologies that allows you to recognize touches on the screen. The grid consists of many light emitters and receivers located on the sides of the screen. It reacts to the blocking of the corresponding rays by objects, on the basis of which it determines the coordinates of the press.

Multi-touch

Multi-touch, which everyone talks about so much and is only growing in popularity, is not a type of touch screen. At its core, multi-touch technology - which is a loose translation of the phrase multi-touch - is an addition to a touch screen (most often built on a projected capacitive principle) that allows the screen to recognize multiple points of contact on it. As a result, the multi-touch screen becomes capable of recognizing gestures. Here are just a few of them:

• Move two fingers together - zoom out image (text)
• Spread two fingers to the sides - increase (Zoom)
• Movement with several fingers at the same time - scrolling text, pages in the browser
• Rotate with two fingers on the screen - rotate the image (screen)

Pros and cons:

Touch screens have been around for a long time in handheld devices. There are several reasons for this:

• Ability to make a minimum number of controls
• Simplicity of the graphical interface
• Ease of control
• Ease of access to device functions
• Expanding multimedia capabilities

However, there are more than enough disadvantages:

• Lack of haptic feedback
• Frequent need to use a pen (stylus)
• Possibility of screen damage
• The appearance of fingerprints and other dirt on the screen
• Higher energy consumption

As a result, it is not always possible to completely get rid of the keyboard, because it is much more convenient to type text using familiar keys. But the touch screen is more interactive, thanks to faster access to menu items and settings of modern gadgets.

Nowadays on the Internet, on various technical forums about tablets and cell phones, you can often come across the word “touchscreen”. What it is? The word itself comes from the English phrase “touch screen”, consisting of two words: “touch” - touch, touch, touch and “screen” - screen. That is touchscreen is the touch screen of your phone, tablet, player or GPS navigator. That is, when you move your finger across the screen of your mobile gadget, you touch the touchscreen, which transmits data about the position of your finger to the operating system, which compares it with the image on the display.
In fact, it is a transparent touch glass that is placed on top of the screen matrix. For ease of replacement and repair, they are separate on most models of mobile devices.

When hit or dropped from a height, it is the touch glass that most often cracks and breaks. After this, it usually doesn't work. But the matrix itself is intact. And the touchscreen can be replaced separately from the display. Thus, it also plays a protective function.

How does the touchscreen work?

Today there are 3 main technologies that differ from each other.

1. Resistive touchscreen

The cheapest to produce and most resistant to dirt are touch screens. They consist of glass and a membrane, between which there are insulators. We press on the screen with a finger, pencil or stylus, the glass pushes through the insulator and closes with the membrane. And the controller reads the click and processes the received information. The main disadvantage of such touch screens is that they are dark (due to low light transmission) and short-lived. In addition, they really don’t like falling.

2. Capacitive screen

Here, special glass is already used, processed with a special material, through which current (alternating voltage) is supplied. You touch the touchscreen with your finger and a current leak occurs, which is detected by the sensors and transmitted to the controller. The reaction will only occur when pressed by hand. The screen will no longer respond to the glove.
This type of touch glass is more durable than resistive glass, although they really don’t like dirt and water.
Due to the fact that there is no membrane, a capacitive touch screen has a light transmittance of about 90%.

3. Surface acoustic wave sensor

This is the most technically complex touch screen. It works by reading reflected surface acoustic waves and converting them into an electrical signal that is transmitted to the controller. Due to such complex technology, the touchscreen is very sensitive to dirt, vibration and electromagnetic interference.
The main advantage is the longest lifespan: about 50 million touches.

Just recently, few could believe that phones with familiar buttons would give way to devices that were controlled by touching the screen. But times are changing and the demand for push-button phones is gradually falling, while the demand for smartphones is growing.

The term “touchscreen” is formed from two words - Touch and Screen, which in English translates as “touch screen”. Yes, that's right - a touchscreen is a touchscreen that you touch when you use your smartphone or tablet. In fact, touch screens are found not only in the world of mobile technology. So, you could see them when depositing funds into your mobile device account through a terminal, at an ATM, in ticket devices, etc.

It's important to note that there are several different ways touch screens work, depending on where and what they're used for. Of course, the cost of technology also varies. So, there is no point in using high-tech touch screens for mobile phone recharge terminals, which cannot be said about the same smartphones.

What is a touchscreen?

Modern smartphones use capacitive touch screens. They are a glass panel on which a layer of transparent resistive material is applied. In the corners there are electrodes that supply low-voltage alternating voltage to the conductive layer. The human body can conduct electric current through itself, and also has a certain capacity. Therefore, when you touch the screen, a leak occurs and the location of this leak is determined by the controller, which uses data from the electrodes at the corners of the panel.

PDAs, which are almost never found on sale today, use resistive screens that, in addition to the glass panel, have a flexible membrane. The surface between them is filled with micro-insulators. When the screen is pressed, the membrane and panel close, after which the controller records the change in resistance and converts it into touch coordinates.

Remember, a capacitive screen does not respond to pressing an object or even the simplest one (you need a stylus with a special tip), while resistive screens respond to absolutely any touch.

Is it possible to replace the touchscreen?

If the user breaks the touchscreen or it fails for one reason or another (for example, it stops responding to touches), it is possible to replace the touchscreen. It is advisable to make a replacement in a specialized service with a guarantee.