Matrixes - what is it? Types of matrices

Today it is almost impossible to find a person who would still use a CRT monitor or an old kinescope TV. This technology quickly and successfully replaced LCD models, which are based on liquid crystals. But matrices are no less important. What are liquid crystals and matrices? You will learn all this from our article.

Prehistory

The world first learned about liquid crystals in 1888, when the famous botanist Friedrich Rainitzer discovered the existence of strange substances in plants. He was amazed that some substances, initially possessing a crystalline structure, completely change their properties when heated.

So, at a temperature of 178 degrees Celsius, the substance is at first turbid, and then completely transformed into liquid. But the opening did not end there. It turned out that a strange liquid is electromagnetically manifested as a crystal. It was then that the term "liquid crystal" appeared.

The principle of LCD matrices

This is the basis for the work of the matrix. What is a matrix? This is a polysemantic term. One of its values is a laptop display, LCD monitor or a modern TV screen. Now we know what the principle of their work is based on.

And it is based on the usual polarization of light. If you remember the school physics course, then there just is told that some substances are capable of transmitting light of only one spectrum. That is why two polarizers at an angle of 90 degrees can not pass light at all. In the case where there is some device between them that can turn the light, we will be able to adjust the brightness of the glow and other parameters. In general, this is the simplest matrix.

Simplified Matrix Device

The usual LCD display will always consist of several permanent parts:

• Lamps for illumination.
• Reflectors that ensure the uniformity of the above illumination.
• Polarizers.
• The substrate is made of glass, on which conductive contacts are deposited.
• Some of the notorious liquid crystals.
• Another polarizer and substrate.

Each pixel of this matrix is formed from red, green and blue dots, the combination of which allows you to receive any of the available colors. If you turn everything on at the same time, the result is white. By the way, what is the resolution of the matrix? This is the number of pixels on it (1280x1024, for example).

What are the matrices?

Simplified, they are passive (simple) and active. Passive - the simplest, in them the pixels are triggered sequentially, from line to line. Accordingly, when trying to establish the production of displays with a large diagonal, it turned out that it is necessary to increase the length of the conductors disproportionately. As a result, not only the value increased significantly, but the voltage also increased, which led to a sharp increase in the number of interference. Therefore, passive matrices can be used only in the manufacture of inexpensive monitors with a small diagonal.

Active varieties of monitors, TFT, allow you to control each (!) Of millions of pixels separately. The fact is that each pixel is controlled by a separate transistor. To prevent the cell from prematurely losing its charge, a separate capacitor is added to it. Of course, due to such a scheme it was possible to reduce the response time of each pixel several times.

Mathematical justification

In mathematics, an object is called a matrix, written in the form of a table whose elements are at the intersection of its rows and columns. It should be noted that matrices are generally widely used in computers. The same display can be treated as a matrix. Because each pixel has certain coordinates. Thus, any image that is formed on the display of the laptop, there is a matrix, in cells which contain the colors of each pixel.

Each value takes exactly 1 byte of memory. Little? Alas, even in this case, only a FullHD frame (1920 × 1080) will occupy a couple of MB. And how much space do you need for a movie for 90 minutes? That's why the image is compressed. The determinant is of great importance in this case.

By the way, what is a determinant of a matrix? It is a polynomial combining the elements of a square matrix in such a way that its value is preserved when transposing and linear combinations of rows or columns. A matrix in this case is a mathematical expression describing the arrangement of pixels in which their colors are encoded. It is called square because the number of rows and columns in it is the same.

Why is it so important? The point is that the Haar transformation is used in the coding. In fact, the Haar transformation is the rotation of points in such a way that they can be conveniently and compactly encoded. As a result, we obtain an orthogonal matrix, for decoding which the determinant is used.

Now we consider the basic types of the matrix (what is the matrix itself, we have already found out).

TN + film

One of the cheapest and most common models of displays today. It is characterized by a relatively fast response time, but rather poor color rendition. The problem is that the crystals in this matrix are arranged so that the viewing angles are negligible. To combat this phenomenon, a special film has been developed, which allows us to expand the viewing angles somewhat.

The crystals in this matrix are lined up in a column, thus reminding the soldiers at the parade. The crystals are twisted into a spiral, so that they perfectly cling to each other perfectly. In order for the layers to adhere well to the substrates, special notches are made on the surface of the substrates.

An electrode regulating the voltage on it is supplied to each crystal. If there is no voltage, then the crystals rotate 90 degrees, so that light freely passes through them. It turns out an ordinary white pixel matrix. What is red or green? How does it work out?

As soon as the voltage is applied, the spiral is compressed, and the compression ratio directly depends on the amperage. If the value is maximum, then the crystals generally do not transmit light, resulting in a black background. To get a gray color and its hues, the position of the crystals in the spiral is adjusted so that some amount of light they pass through.

By the way, by default, all colors are always activated in these matrices, as a result of which the pixel is white. That's why it's so easy to identify a burned pixel that always appears as a bright dot on the monitor. Considering that color rendition of matrices of this type is always a problem, it is also very difficult to achieve black display.

To somehow fix the situation, the engineers placed the crystals at an angle of 210 °, as a result of which the quality of the color rendition and the response time increased. But in this case, too, there were overlaps: unlike classic TN-matrices, a problem arose with shades of white, the colors turned out to be blurred. So there was technology DSTN. The essence of it is that the display is divided into two halves, each of which is controlled separately. The display quality improved dramatically, but the weight and cost of monitors increased.

That's what a matrix in a TN + film type notebook is.

S-IPS

Hitachi, as it should have been suffering from the drawbacks of the previous technology, decided not to try to improve it any more, but simply to invent something radically new. Moreover, in 1971 Gunther Baur found out that crystals can be placed not in the form of twisted columns, but stacked parallel to each other on a glass substrate. Of course, in this case, the transmitting electrodes are also fixed there.

If there is no voltage on the first polarization filter , the light passes through it freely, but it lingers on the second substrate, the polarization plane of which is always at an angle of 90 degrees with respect to the first one. Due to this, not only the speed of the monitor's response is sharply increased, but also the black color is really black, and not the variation of the dark gray hue. In addition, a large advantage is the expanded viewing angles .

Disadvantages of technology

Alas, the rotation of the crystals, which are parallel to each other, takes much longer. And because the response time on older models reached a truly cyclopean value, 35-25 ms! Sometimes it was possible to observe even a train from the cursor, and it's better to forget about the dynamic scenes in toys and films.

Since the electrodes are located on the same substrate, much more electricity is needed to turn the crystals in the desired direction. That's why all monitors based on IPS-matrixes rarely get the star of Energy Star for economy. Of course, for backlighting, it is also necessary to use more powerful lamps, and this in no way improves the situation with increased electricity consumption.

The manufacturability of manufacturing such matrices is high, and therefore until recently they were very, very expensive. In short, with all the advantages and disadvantages, such monitors are great for designers: the quality of the color rendition is excellent, and in some cases, the response can be sacrificed.

That's what an IPS matrix is.

MVA / PVA

Since both of the above types of matrices have flaws, which are virtually impossible to eliminate, Fujitsu has developed a new technology. Actually MVA / PVA is a modified version of IPS. The main difference is the electrodes. They are located on the second substrate in the form of a kind of triangles. This solution allows you to react faster to crystals to change the voltage, and color rendering is much better.

Cameras

And what is the matrix in the camera? In this case, the so-called conductor crystal is also known, which is also known as a charge-coupled device (CCD). The more cells in the matrix of the camera , the better. When the camera's shutter opens, a flow of electrons passes through the matrix: the more of them, the more the current is stronger. Accordingly, in the dark parts of the current is not formed. The parts of the matrix that are sensitive to certain colors, as a result, form a complete image.

By the way, what is the size of a matrix, if we talk about computers or laptops? It's simple - so called the screen diagonal.