Capacitive and resistive touch screens. Tablets: Which screen is better, capacitive or resistive

Nowadays you won’t surprise anyone with a touch screen. Moreover, it is already strange to see devices without a sensor, especially when it comes to mobile gadgets. This is due to the desire to increase the working surface area. But how often do we think about what type of display is used in a particular device? Has it ever happened that, having bought a new tablet or smartphone, we try to control it using the usual digital pen, but bad luck, the device simply does not respond to its touch. Apparently, the screen is made using a different technology, capacitive, which is gradually beginning to displace its predecessor, the resistive type display.

You can find a large number of touch screens that differ not only in design features, but also in their operating principles. Today, there are the following types of touch screens: resistive, capacitive, projection-capacitive, matrix, surface acoustic wave touch screen, infrared, strain gauge, inductive.

Currently, there are two main types of touch screens used in electronic technology: resistive and capacitive. We will talk about them in more detail, and also try to highlight the strengths and weaknesses of each.

First, let's look at the operating principle of a resistive touch screen. It consists of a glass panel and a flexible plastic membrane, on which a resistive coating is applied. The space between the glass and the membrane is filled with micro-insulators, which in turn reliably insulate the conductive surfaces, evenly distributed over the active area of the screen. When you press the display, the panel and membrane close, and the controller, using an analog-to-digital converter, registers the change in resistance, converting it into touch coordinates. It is for this reason that such a screen can be pressed with any hard object, it can be a fingernail, a special stylus, or even an ordinary pencil. As a consequence of this structure, resistive screens gradually wear out, which is why there is a need for periodic calibration of the screen so that when you press the display, the coordinates of the touch point are correctly processed.

There are four-, eight-, five-, six- or seven-electrode screens. The simplest to manufacture, and therefore the cheapest, are four-electrode ones. They can withstand only 3 million clicks at one point. Five-wire ones will already be much more reliable - up to 35 million clicks; in them, four electrodes are located on the panel, and the fifth is located on a membrane, which is coated with a conductive composition. It is worth noting that five-wire and subsequent versions of six- and seven-wire screens continue to work even if part of the membrane is damaged.

Advantages

The advantages of a resistive screen include the low cost of its production, and, consequently, the low cost of the device in which it is used. In addition, it is worth noting that the sensor response here does not depend on the condition of the screen surface; even if dirty, the touchscreen remains just as sensitive. You should also highlight the accuracy of hitting the desired point, because a dense lattice of resistive elements is used.

Flaws

As a disadvantage of resistive screens, we highlight low light transmission, no more than 70% or 85%, so increased backlight brightness is required. It is also low sensitivity, i.e. Simply touching with your finger is not enough, pressure is required, so you cannot do without a digital pen or long nails. This type in most cases does not support multi-touch, i.e. the screen only understands one touch. When interacting with the screen, you need to make some effort to transmit any command, and if you overdo it, you can not only scratch it, but also damage the display. As mentioned above, for proper functioning it is necessary to periodically calibrate the screen.

Capacitive touch screen

A capacitive screen is a glass panel that is coated with a transparent resistive material, typically an alloy of indium oxide and tin oxide. Electrodes are installed at the corners of the panel, supplying a low-voltage alternating voltage to the conductive layer; they monitor the flow of charges in the screen and transmit data to the controller, thus determining the coordinates of the touch point. Before touching, the screen has some electrical charge; when touched with a finger, a point appears on the conductive layer, the potential of which is less than the potentials of the electrode, since the human body has the ability to conduct electric current and has a certain capacity. There are no flexible membranes on the screen, which ensures high reliability and allows you to reduce the brightness of the backlight. This type of screen is capable of simultaneously determining the coordinates of two or more touch points, which means multi-touch support.

Projection-capacitive screens have become a subtype of capacitive screens. They work on a similar principle. The difference is that the basic elements in them are located not on the outside of the screen, but on the inside, making the sensor more protected. This type of display is mainly used in modern mobile devices.

Interaction with a capacitive screen should only be carried out with a conductive object, a bare finger or a special stylus that has electrical capacitance. The number of clicks before the sensor elements fail reaches more than 200 million times.

Advantages

One of the advantages of capacitive screens is that even in bright sunshine, visibility remains quite good, which cannot be said about a resistive screen, since it reflects a lot of ambient light. Another advantage was the ability to quickly and accurately recognize touch without the use of additional accessories. The undoubted advantage of screens of this type is the longer service life of the sensor compared to the previous type. A “multi-finger” interface or multi-touch has also appeared, although not all devices with a screen of this type are fully implemented.

Flaws

The negative aspects of using a capacitive touch screen include a higher cost due to the complexity of production. Interaction with the display is only possible by touching a material that is a conductor. For this reason, special capacitive styluses or gloves are purchased to work with it; this becomes especially important in cold weather, and this is another expense item.

To summarize, let us recall that resistive screens are pressure sensitive, while capacitive screens are touch sensitive. The accuracy of capacitive displays is comparable to that of resistive displays, but the capacitive type is more reliable due to the absence of a flexible membrane, and fewer layers make them more transparent.

There is an opinion that resistive displays have already outlived their usefulness, and the future belongs to capacitive displays. Indeed, the transition from mechanical-electrical input to electrical already means a lot, since the accuracy of determining coordinates has increased, and multi-touch has appeared.

However, today there are still a large number of devices with resistive screens on the electronics market, but they are slowly beginning to be replaced by gadgets with capacitive sensors. Observing this trend, one can assume that the former will soon disappear altogether.

An information input device, which is a screen that responds to touches. There are many different types of touch screens that operate on different physical principles. But we will consider only those that are found in mobile phones and other portable equipment.

How resistive touch screens work

Resistive touch screens come in two types, four-wire and five-wire. Let's consider the operating principle of each type separately.

Four-wire resistive screen

Operating principle of 4-wire resistive touch screen

A resistive touch screen consists of a glass panel and a flexible plastic membrane. A resistive coating is applied to both the panel and the membrane. The space between the glass and the membrane is filled with micro-insulators, which are evenly distributed over the active area of the screen and reliably insulate the conductive surfaces. When the screen is pressed, the panel and membrane are closed, and the controller with analog-to-digital converter registers the change in resistance and converts it into touch coordinates (X and Y). In general terms, the reading algorithm is as follows:

A voltage of +5V is applied to the upper electrode, and the lower one is grounded. The left and right are short-circuited and the voltage on them is checked. This voltage corresponds to the Y-coordinate of the screen.
Similarly, +5V and ground are supplied to the left and right electrodes, and the X-coordinate is read from the top and bottom.

Five-wire resistive screen

The five-wire screen is more reliable due to the fact that the resistive coating on the membrane is replaced by a conductive one (the 5-wire screen continues to work even with a cut through membrane). The rear glass has a resistive coating with four electrodes at the corners.

Operating principle of 5-wire resistive touch screen

Initially, all four electrodes are grounded, and the membrane is “pulled up” by a resistor to +5V. The voltage level on the membrane is constantly monitored analog-to-digital converter. When nothing is touching the touch screen, the voltage is 5V.

As soon as the screen is pressed, the microprocessor detects the change in membrane voltage and begins to calculate the coordinates of the touch as follows:

A voltage of +5V is applied to the two right electrodes, the left ones are grounded. The voltage on the screen corresponds to the X-coordinate.
The Y-coordinate is read by connecting both upper electrodes to +5V and to ground both lower ones.

How capacitive touch screens work

A capacitive (or surface capacitive) screen takes advantage of the fact that a large capacitance object conducts alternating current.

Operating principle of a capacitive touch screen

A capacitive touch screen is a glass panel coated with a transparent resistive material (usually an alloy of indium oxide and tin oxide). Electrodes located at the corners of the screen apply a small alternating voltage (the same for all corners) to the conductive layer. When you touch the screen with your finger or other conductive object, current leaks. Moreover, the closer the finger is to the electrode, the lower the screen resistance, which means the greater the current. The current in all four corners is recorded by sensors and transmitted to the controller, which calculates the coordinates of the touch point.

In earlier models of capacitive screens, direct current was used - this simplified the design, but if the user had poor contact with the ground, it led to failures.

Capacitive touchscreens are reliable, about 200 million clicks (about 6 and a half years of clicks every second), do not leak liquids, and tolerate non-conductive contaminants very well. Transparency at 90%. However, the conductive coating is still vulnerable. Therefore, capacitive screens are widely used in machines installed in protected areas. They do not respond to a gloved hand.

Operating principle of projected capacitive touch screens

A grid of electrodes is applied on the inside of the screen. The electrode together with the human body forms a capacitor; the electronics measures the capacitance of this capacitor (supplies a current pulse and measures the voltage).

Operating principle of projected capacitive touch screen

The transparency of such screens is up to 90%, the temperature range is extremely wide. Very durable (the bottleneck is the complex electronics that process clicks). POE can use glass up to 18 mm thick, which results in extreme vandal resistance. They do not react to non-conductive contaminants; conductive ones are easily suppressed using software methods. Therefore, projected capacitive touch screens are used in vending machines installed on the street. Many models react to a gloved hand. In modern models, designers have achieved very high accuracy - however, vandal-resistant versions are less accurate.

PEEs even react to the approach of a hand - the response threshold is set by software. Distinguish between pressing by hand and pressing with a conductive pen. Some models support multi-touch. Therefore, this technology is used in touchpads and multi-touch screens.

It is worth noting that due to differences in terminology, surface- and projected-capacitive screens are often confused. According to the classification used in this article, the iPhone screen is projected capacitive.

Conclusion

Each type of touch screen has its own advantages and disadvantages; for clarity, let’s look at the table.

	Resistive 4-wire	Resistive 5-wire	Capacitive	Projected capacitive
Functionality
Hand in glove	Yes	Yes	No	Yes
Solid conductive object	Yes	Yes	Yes	Yes
Solid non-conductive object	Yes	Yes	No	No
Multi-touch	No	Yes	Yes	Yes
Pressure measurement	No	No	No	Yes
Ultimate transparency, %	75	85	90	90
Accuracy	High	High	High	High
Reliability
Lifetime, million clicks	10	35	200	∞
Protection from dirt and liquids	Yes	Yes	Yes	Yes
Resistance to vandalism	No	No	No	Yes

The article was written based on materials from the site

If you go to a modern mobile phone store and get acquainted with the products on offer, the specifications for most devices on the display will indicate: “Screen type - capacitive.” Those who often change mobile communication devices are familiar with this term, but what to do if a person did not strive to buy the latest, preferring proven solutions?

He can only be at a loss: “Capacitive screen - what is it?”

Data entry technology

The principle of touch typing is now used everywhere. For example, ATMs or machines for making various types of payments, on the panels of which there are a minimum of buttons, and the required numbers are entered by clicking on the corresponding image, can be found in almost every large store. were first proposed back in the seventies, but they were not widespread due to insufficient accuracy of recognition of the pressure zone and the complexity of implementation. But work to improve this solution continued.

Sensors in phones

When models of mobile communication devices with large screens appeared, the question of ergonomics immediately arose. Of course, it was possible to reduce the already small block of buttons, but this would have a very negative impact on ease of use. Compromise solutions were used - the so-called “sliders”, but this made the device too thick and made it less reliable due to the need to use a mechanical movable connection. Manufacturers began searching for a solution. And it was found. They turned out to be significantly improved by that time and ideally suited for telephones.

Resisting pressure

The first models of such screens were made according to the resistive principle. Due to a number of features, such sensors are still used today. consists of two completely transparent plates: the outer one, which receives pressure, is made flexible, and the inner one, on the contrary, is rigid. The space between them is filled with a transparent dielectric material. An electrically conductive layer is sprayed onto both plates on the inner sides. It is specially connected by conductors to a controller that constantly supplies low voltage to the layers. This entire “sandwich” is fixed on the main display. When a person presses on a section of the screen, the plates touch at a certain point, causing a current to flow. By determining the resistance values along two Cartesian axes, you can find out with sufficient accuracy exactly where the pressing occurred. This data is transferred to the running program, which further processes it.

Resistive sensors are inexpensive to produce and work well at low temperatures.

Capacitive screens

Sensors operating on the capacitive principle are much more advanced. Touchpads in laptops are a prime example of such solutions. On foreign websites, the characteristics of phones with this technology indicate “Capacity”. Unlike the resistive solution described above, mechanical pressing is not at all important here. In this case, the human body’s ability to accumulate is used, acting as a classic capacitor. Capacitive screens are more durable and have excellent responsiveness. There are two implementation methods: surface and projection. In the first case, a transparent layer of conductive material is applied to the surface of glass or plastic. It is constantly exposed to electrical potential from the controller. Just touch a point on the screen with your finger, and the battery leaks into the human body. It can be easily determined and the coordinates transferred to the running program. Projected capacitive screens work differently. Behind the outer glass of the display is a grid of transparent sensor elements (they can be seen at a certain angle and lighting). If you touch the point, then, in fact, a capacitor will be formed, one of the plates of which is the user’s finger. The capacitance in the circuit is determined by the controller and calculated. This solution allows you to implement multi-touch technology.

If you are not one of the tech-savvy users and you will soon be faced with the question of choosing a mobile phone or smartphone with a touch screen, you will probably come across terms such as “capacitive screen” or “resistive screen” when reading the specifications of mobile devices. And then a completely logical question will come to your mind - which one is better: resistive or capacitive? Let's find out how touch displays differ, what types exist, and what their advantages and disadvantages are.

RESISTIVE SCREENS

To put it in simple language, avoiding clever technical terms and phrases, a resistive touch screen is a flexible transparent membrane on which a conductive (in other words, resistive) coating is applied. Under the membrane there is glass, also covered with a conductive layer. The principle of operation of a resistive screen is that when you press the screen with a finger or stylus, the glass shorts...

0 0

Touch screens on devices are divided into two main types, which have significant differences.

Resistive touch screen.

This screen consists of several layers. When you press the screen, a short circuit occurs with the membrane. The gadget registers this change, converts it into coordinates, by which it determines where exactly you clicked, and reacts to the click accordingly. For example, opens a program or selects a specific menu.

High strength. Such screens are made from various types of fiberglass. Low cost. The resistive screen has a simple operating principle.

The disadvantage is low sensitivity. Simple finger touches are often not recognized by the device, so you will have to use a stylus or long nails.

Capacitive touch screen.

This screen consists of a layer of glass covered with an electrical conductor. The human body is a good conductor of electricity, so when you touch the screen...

0 0

Before considering a capacitive or resistive screen, you need to decide what touch technology is in general. Everything is clear here: this is a screen that determines the coordinates of the press. In scientific terms, this refers to a method of controlling the interface with which the user can click directly on the place of interest. At the moment, there are several methods for implementing touch screens. It is worth considering each separately.

Resistive technology

To decide which type of screen, capacitive or resistive, is best for you, you need to consider them. The second option involves the use of a certain production technology. At the bottom there is a glass panel, on top of which there is a transparent flexible membrane. There is a conductive coating on the panel and membrane, that is, resistive. When you press the screen, a short circuit occurs at a certain point. If you know the voltage on...

0 0

Resistive touch screen

0 0

Capacitive vs resistive ArchivesMobilis

How do capacitive screens used in the iPhone and other modern mobile devices differ from other types of touch displays? And is this the future?

I have repeatedly been convinced that ordinary users are completely unaware of the existence of different types of touch screens and are truly surprised to learn that the lack of response of the display of a freshly purchased communicator to the usual poking with a pencil is not at all a sign of a malfunction. It's just a different screen, built on a different technology. Even some sellers are confused in the readings, attributing to displays of one type the properties of others. So first we will conduct a brief educational program, after which you will be able to distinguish different types of screens literally by touch. And then we’ll talk about which of them is the future.

Modern mobile devices - smartphones, communicators, players - use...

0 0

Often, when choosing an Internet tablet, a person reads a lot of reviews and reviews and simply drowns in new, unfamiliar terms and concepts. So, for example, not everyone knows what a resistive screen is. There is hardly any need to prove that the display is the most important part of a Tablet PC (or any other mobile device), so let’s understand this concept.

What is a resistive screen?

The answer can be very short:

A resistive touch screen is a display made of the same technology. This provides its special properties compared to another common type of screen - capacitive.

Now let’s take a closer look at what this technology is and what it means for the end user (tablet buyer).

Resistive display manufacturing technology

In general terms, the problem of turning a stylus or fingernail into something like a computer mouse is achieved in the following way.

The sensor consists of two (usually) layers: glass and...

0 0

Resistive or capacitive touch screen

To stop getting confused, just remember: resistive screens are pressure sensitive, while capacitive screens are touch sensitive. This difference is due to the design of the displays, and it is in principle impossible to train, for example, a capacitive screen to recognize pencil presses.

Working principle of resistive touch screen

A resistive touch screen is like a sandwich consisting of layers, if we speak in analogies. When you press the screen, it closes with the membrane, the device registers the change in resistance and converts it into coordinates, so your tablet knows that you pressed here and reacts accordingly. For example, opens an application or pauses the game. Their strengths are that they are quite durable, as they are made from various types of fiberglass. Considering that it is a fairly simple design, the resistive screen also has a relatively low cost, so a resistive touch screen...

0 0

A touch screen is an information input device based on the coordinate sensing principle that responds to touch. They usually become an alternative to a whole bunch of mechanical buttons, which is very convenient, as it allows you to combine the display and input device. The reliability of such a system is much higher due to the fact that there are no mechanical or moving parts.

The very first models of touch screens were created back in the late sixties of the last century, it was then that the scientist Samuel Hurst realized that he did not want to read kilometers of recorder tapes. In 1971, he founded the Elotouch company, which released the eliograph, which was the first computing device to have a resistive touch screen. After some time, his company merged with another called Siemens, after which it became known as Elographics. Thanks to this collaboration, touch panels for picture tubes were developed...

0 0

Display: capacitive or resistive, which is better? When choosing a touchscreen smartphone, the question may arise, which touchphone is better: with a resistive or capacitive screen? Let's say right away that none of these technologies is qualitatively superior to the other; both of them have their pros and cons. So the user should compare all the advantages and disadvantages and choose the lesser of two evils =)
In this article, we will talk about the advantages and disadvantages of capacitive and resistive screens.
Features of resistive type screen:
The resistive touch screen is characterized by a relatively low cost and maximum resistance to contamination. The resistive screen responds to touch with any hard, smooth object: a hand (including a gloved one), a stylus, a credit card, a stylus, while in some phones touches are accompanied by a response, vibration feedback, which makes work more comfortable and enjoyable. Plus, resistive technology allows the use...

0 0

Your phone's touchscreen: resistive, capacitive or projected capacitive

Touch screens today are an integral attribute of a modern mobile phone, although they became widespread relatively recently - in 2007. And if you are planning to buy a smartphone, you are unlikely to find among the new models those that are not equipped with a touch screen. Despite the fact that adherents of conventional hardware keyboards are having a hard time switching to touch controls, more and more touch devices are being produced. And for those who value convenient typing, touch phones are produced in the classic form factor or in the side slider form factor, which are additionally equipped with hardware QWERTY keyboards.

Touch phones and smartphones in different form factors

Often the phrase “touch screen” is replaced by another - “touchscreen”, which is a combination of two English words (touch - touch, touch and screen -...

0 0

Tablets, or tablets as they are also called, based on the Android operating system, are one of the fairly new gadgets that will allow you to communicate with your friends, browse the World Wide Web (Internet), as well as watch movies and listen to your favorite music. They are usually of a small flat shape, have lost a significant part of their mass and a rather voluminous keyboard, which is now associated with their older brother, the laptop. If there is no keyboard, you ask, then how to work with them?

Every tablet has a touch screen. It's a screen that responds to your touch, just like a laptop's touchpad. This way, instead of clicking on icons with your mouse, you can simply touch them with your finger or stylus (looks like a pen, but without the ink).

There are different types of touch displays, so let's figure out what they are and the differences between them:

Resistive touch screen

Resistive...

0 0

Hello dear readers. Because I’m already tired of the fact that various unscrupulous (and more often simply ignorant) journalists are constantly speculating on the topic of touch screens, I decided to introduce a small educational program on the concepts of resistive touch screen, capacitive touch screen and multitouch. After reading this article, you will understand why the presence of a capacitive touch screen does not mean multi-touch, and also why the iPhone has real multi-touch, while others have only a crooked attempt to imitate it. I warn you in advance that the article was not paid for by anyone, and the power structures of the Russian Federation have nothing to do with its appearance at all.

So, first, let's define what a touch screen is. Everything is simple here: this is a screen that tracks the coordinates of the press. Or, more scientifically, it is a method of controlling an interface that allows the user to tap directly on the screen. In short, it’s a no brainer what it is. There are several methods for implementing a touch screen. About...

0 0

The screens of modern devices can not only display images, but also allow you to interact with the device through sensors. Initially, touch screens were used in some pocket computers, and today touch screens are widely used in mobile devices, players, photo and video cameras, information kiosks, etc. Moreover, each of the listed devices can use one or another type of touch screen. Currently, several types of touch panels have been developed, and accordingly, each of them has its own advantages and disadvantages. In this article we will look at what types of touch screens there are, their advantages and disadvantages, as well as which type of touch screen is better.

There are four main types of touchscreens: resistive, capacitive, surface acoustic wave, and infrared. In mobile devices, only two are most widespread: resistive and capacitive....

0 0

With the era of the advent of touch screens, people who buy a Chinese mobile phone often do not suspect that there are different types, and if the sensor on your phone does not work well, this does not mean that your mobile phone is broken, but perhaps simply that this phone has a different one. a type of screen that you are not yet used to.

And now we will help you sort out this confusion. There are two types of touch screens in Chinese phones: resistive screen and capacitive screen. Next we will talk in more detail about each of them. Then you will be able to distinguish these screens from the first touch.

So that you stop getting confused, I suggest you remember the simple truth in these screens - resistive screens are pressure sensitive, and capacitive screens are touch sensitive. They have a completely different display design, and it is basically impossible to accustom, for example, a Chinese mobile phone with a capacitive screen to a stylus or to a nail.

The resistive screen is a glass...

0 0

Nowadays, touch screens have long ceased to be exotic. They all look similar on the outside, but are these displays actually the same? Let's look at the design of the main types of sensitive screens, their advantages, disadvantages and scope of application.

Today, the most widely used sensors are those based on capacitive and resistive technologies, as well as their varieties.

"Multi-touch"

This is the name of the technology that allows you to recognize touch screen presses at several points simultaneously. This opens up new possibilities in device management. An example of the use of multi-touch technology is the Apple iPhone interface.

Capacitive touch screens

The touch display, which operates on a capacitive principle, actually responds to touch. It consists of a glass panel coated with a transparent conductive compound. At the corners of the panel there are four electrodes to which alternating current is supplied....

0 0

A touch screen is a device for input and output of information through a touch- 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 a regular screen comes to the rescue - Touch Screen, which is also known as Touch Panel, touch panel, 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...

0 0

The first appearance of touch screens occurred in the era of handhelds of yesteryear - PDAs or, in English, PDAs. The gadgets were interesting, but absurdly low-functional, and therefore did not catch on, unlike touchscreens.

Moreover, the latter have not only stood the test of time, but have also become the cornerstone of the concept of all modern mobile gadgets. It’s almost impossible for us to imagine something non-stationary and with a QWERTY keyboard, but in recent years touch screens have “learned” to be truly responsive and easy to use. Although their designs have hardly changed in principle and are divided into the same 3 main categories.

Resistive systems

Imagine a conductor in the form of a thin and flexible metal plate, and opposite it is a glass panel coated with conductive paint. If you press something on the metal plate, it will bend and touch the coating on the glass. And since electric currents are constantly running across both surfaces...

0 0

Resistive or capacitive screen? Resistive! October 26th, 2014

How do capacitive screens used in the iPhone and other modern mobile devices differ from other types of touch displays? And is this the future?

You need to choose a RESISTIVE SCREEN!

Review and explanation

Modern mobile devices - smartphones, communicators, players - use two types of touch screens: resistive and capacitive. Moreover, more than 90% of all touch screens today are of the resistive type, although there is already a clear trend toward an increase in the share of capacitive screens.

A resistive screen is a glass liquid crystal display on which a flexible membrane is applied. A resistive composition is applied to the contacting sides, and the space between the planes is divided by a dielectric. Electrodes (four or eight, five or six and seven) are attached to the edges of the plates. It is easy to guess that when pressed, the screen and the membrane come into contact at the point of pressing, the coordinates of which are calculated by sequentially applying current to the upper and lower plates and measuring the voltage at the point of contact of the plates. That is why you can press such a screen with any hard object - from a fingernail and a stylus to a pencil or a match, and it will work.

Operating principle of a five-wire resistive screen

Due to their design, resistive screens and, especially, their conductive layer are subject to gradual wear, which is why there is a need for periodic calibration of the screen. The simplest and cheapest four-electrode screens can withstand only 3 million clicks on one point. Several times more reliable - up to 35 million clicks - are five-wire ones, where four electrodes are located on the screen plate, and the fifth is on a membrane coated with a conductive composition and serves only as a kind of “probe”. In addition, five-wire and its modifications 6 and 7-wire screens continue to work even if part of the membrane is damaged.

The disadvantages of resistive screens also include low light transmission - no more than 70-85%, which requires increased backlight brightness. But these screens are extremely cheap to produce, which explains their wide distribution.

A capacitive touch screen is generally a glass panel on which a layer of transparent resistive material is applied. Electrodes are installed at the corners of the panel, supplying low-voltage alternating voltage to the conductive layer. Since the human body is capable of conducting electrical current and has some capacitance, when touching the screen, a leak appears in the system. The location of this leak, that is, the point of contact, is determined by a simple controller based on data from the electrodes at the corners of the panel.

Operating principle of a capacitive screen

There are no flexible membranes on the screen, which ensures high reliability and allows you to reduce the brightness of the backlight. Unfortunately, you cannot poke them with a stylus or fingernail, since the command simply will not be recognized. Only with your finger. Such a screen also does not like negative temperatures: at best, the accuracy of determining coordinates decreases; at worst, it simply stops responding.

Operating principle of a projected capacitive screen

Unfortunately, on the simplest capacitive screen, which is now installed in the cheapest “touch” phones, it is impossible to organize a fashionable “multi-finger” multi-touch interface - four electrodes in the corners are capable of recording only one click at a time. Projected-capacitive displays are free from this drawback, in which a whole grid of conductors (or rows of electrodes) is applied to the back of the screen, to which a weak current is supplied, and the point of contact is determined by points with increased capacitance. By the way, such screens are capable of reacting even to the approach of a hand (and therefore to a gloved hand) - it all depends on the sensitivity settings.

Many experts, not without reason, believe that resistive screens are a thing of the past, and capacitive screens are the future. Indeed, just the transition from a mechanical-electrical input system to a purely electrical one is certainly progress. Reliability and accuracy of coordinate determination have increased, the need for calibration has disappeared, and a “multi-finger” interface has appeared.

The move away from resistive displays has spurred the development of truly seamless user interfaces optimized for finger control. In modern communicators, you no longer need to aim a sliver at microscopic interface elements inherited from “large” operating systems. Please note that the latest Windows Phone 7 is absolutely nothing like the rest of the family of “mobile windows” of previous generations, in which there was nothing to do without a tiny stylus.

Skeptics will note that you can no longer draw on a capacitive screen with a regular plastic stylus or some random object, or write down a memo by hand. To do this, you will have to buy a special stylus with an electrical capacity. HTC even patented such a capacitive stylus (http://www.devicewire.co.uk/official-htc-hd2-capacitive-stylus) and asks about $30 for it. But how often do we draw on our phones or use handwriting? As they say in certain circles, a little less often than never. But touch tablets for drawing use completely different technologies, and they are not going anywhere.

The only reason why resistive screens still occupy the lion's share of the market is because they are extremely cheap. In addition, over the course of several years, all the largest vendors managed to produce such a number of very diverse and not at all cheap handsets with resistive displays that it would be like death for them to immediately write them into the category of obsolete. In any case, there will be more and more devices with capacitive screens, and fewer and fewer devices with resistive screens. In a few years, we won’t even remember that we once poked special thin slivers into the screen of smartphones.

ANALYSIS AND CONCLUSION

Analyzing the principle of operation of two different screens, we can conclude that in resistive the screen has no impact on the human body by electromagnetic radiation and indirect current. Conversely, the screen capacitive this is practically an electromagnetic field into which you immerse your hand to perform certain actions. Moreover, this electromagnetic field begins to be physically felt already from a distance of 5-10 cm from the screen.

Do not forget that blood in the human body is carried by hemoglobin, which contains iron. Using capacitive screen, you actually conduct electromagnetic treatment of your blood, which then distributes these results throughout the body.

A rheumatist, as a person most sensitive to effects on the cardiovascular system, will immediately answer: “After five minutes from the capacitive screen, my hand hurts and my bones ache! Throw away this shit immediately! Don’t give it to children!”

If you work a lot and often with touch screens, then always choose a resistive one. In principle, children should not be given access to capacitive screens. We don't need multitouch if such crap accompanies its use. Improve resistive screens to multi-touch and don’t come to us with capacitive screens.

Analysis and conclusion: Forensic technical examination of the CNEAT institution in Samara: