IPS (InplaneSwitching -high quality liquid crystal matrix, which was created to eliminate the main disadvantages of matrices on technology.

Principle of operation:

Have wide angles review, one of the best indicators color quality and contrast ratio among LCD matrices. However, due to large steps, an interlayer of crystals and a certain arrangement of electrodes, it has a significantly higher about Faster response time than matrices TN. This happens due to the longer time required to position all the crystals in the desired position.

Popular with enthusiasts, graphic designers, pre-printers working with professional graphics packages where color quality, contrast and hue accuracy are important.

These monitors have some about greater thickness than TN models. This is due to the need to use more powerful lamps in terms of light-penetrating ability and brightness, and therefore more layers are required for the scattering material.

Often found IPS panels illuminated by LED lighting. They use either powerful LEDs or matrices with increased light transmittance. The first case is used on large panels, the second on small ones (monitors, smartphones, tablet PCs). For example, they have increased light transmission S-IPS II and E-IPS. All this, of course, is not without damage to the characteristics of the matrix.

Among competitors IPS you can select matrices that have their drawbacks, but also pluses in the form of a much better static contrast ratio, for example.

The most common varieties and letter designations of IPS matrices:

S-IPS (Super IPS) was developed in 1998 year, as an improved technology of the standard IPS. It has improved contrast and faster response time than the original matrix.

AS-IPS (Advanced Super-IPS, 2002 ) - in comparison with S-IPS matrix, improved contrast and transparency of the matrix itself, which improves brightness.

H-IPS (Horizontal IPS, 2007 ) - the contrast is even more improved, as well as the optimization of the white color, making it more realistic. Designed for professional photo editors, designers, 3D/2D craftsmen, etc.

P-IPS (Professional IPS, 2010 ) - provides 102 -percentage coverage of the color space NTSC and 98 -percentage Adobe RGB (30 bit or 10 bit for each subpixel ( 1.07 billion colors)) which makes this LCD technology, one of the best in the world. Also, improved response time and depth true color mode. Is a variety H-IPS. It is rightfully considered professional type of matrices and the price for it remains one of the highest.

E-IPS (Enhanced-IPS, 2009 ) - improved response time (up to 5ms), improved transparency, which allowed the use of less powerful and cheaper backlights. It is worth noting that these improvements will most likely not have the best effect on color reproduction and the quality of halftones, because some of the crystals were technically cut. It is also a variety H-IPS.

S-IPS II - similar in characteristics to E-IPS. Slightly less glow(glow) effect. Essentially not a derivative H-IPS, but is considered a separate branch.

The promotion and development of these matrices is mainly carried out by the company LG Displays.

AT late 2011 year, an alternative to matrices from LG, a Korean electronics manufacturer Samsung. The development was named pls (Plane-to-Line Switching) and in addition to a similar name, it is also based on IPS principles of constructing matrices.

pls - matrices have more favorable characteristics in terms of the ability to place pixels more densely, in high light transmission and brightness, as well as slightly lower power consumption than IPS. But have pls and significant downsides. The lowest contrast among LCD matrices, color gamut no more sRGB.

These two flaws automatically rule out creation. Samsung from the camp of professional solutions, but pushes the boundaries for the mass market, where development, in fact, and met.

matrices pls, most likely will be used both in monitors and in TVs, smartphones and tablets of the company and its partners.

In modern digital devices(monitors, TVs, smartphones, tablets, etc.) to display the picture, liquid crystal (LCD) matrices are most often used. One of the technologies for constructing this matrix is ​​IPS. Literally, translated from English - in plane switching - means "switching in one plane."

In order to understand what kind of switching is and why it is necessary to understand exactly how the picture is built on the LCD screen.

General principles for constructing an LCD matrix

Replaced cathode ray tubes, LCD monitor construction technology includes as a key element liquid crystal matrix. This matrix is ​​located on the front surface of the monitor. Since the matrix only composes the picture, it requires a backlight, which is part of the display. The LCD matrix consists of the following items, which are structurally implemented in the form of layers:

• color filter;
• horizontal filter;
• transparent electrode (front);
• actual liquid crystal filler;
• transparent electrode (rear);
• vertical filter.

This multilayer structure can also include special anti-reflective layers, protective coatings, sensor layers (usually capacitive), but they are not the key to displaying the picture. The picture itself is built from pixels, which are formed from subpixels of the basic colors (RGB): red, green and blue. Light passing from the rear side of the matrix passes through both polarizing filters and the LCD layer, through the color filter. The color filter just colors these light streams one of three RGB colors. The principle of constructing pixels from subpixels is a separate extensive topic and will not be considered within the framework of this review.

Actually, LCD technology itself is how the light beam will pass to the user. And if it passes, then how bright will it be. The LCD matrix crystals in the cells transmit light or not, depending on what voltage is applied to the electrodes. The efficiency of matrices is determined by the technology of its construction and the material used. To date, the most widely used matrices are TN and IPS and their improved varieties.

Technology for constructing TN matrices

Historically, this type of matrix appeared significantly earlier than IPS. Literally TN (English - "twisted nematic") means "twisted crystal". This phrase perfectly defines the way it works. The molecules of crystals in their layer are twisted by 90° relative to each other. They occupy this position if no voltage is applied to the electrodes in their subpixel. In this case, the light passes freely (due to the fact that the polarization angle of the second filter differs by 90 ° from the first one).

When voltage is applied to the electrodes, the crystal molecules pass from a free state to an ordered one: along the polarization line of the input filter. Because of this, the light does not go beyond the limits of the second filter, and the subpixel is not painted in the color of the filter, but degenerates into black.

• Pros:
  • the cost of manufacturing matrices is minimal,
  • the response time is the fastest, which is very important for gaming computers.
• Minuses:
  • poor viewing angles, brightness and color reproduction change significantly when viewed on a device not at a right angle;
  • very low contrast, resulting in a faded picture and very light blacks (not at all suitable for professional graphics).
• dead pixel at the same time, it always has a white color (if there is no voltage on the electrodes, then the light filter is always open).

Technology for building IPS matrices

Switching of crystals in IPS occurs in one plane, which, in fact, is indicated by the original form of its name (English - “in plane switching”). In such matrices, all electrodes are located on the same back substrate. In the absence of voltage on the electrodes, all crystal molecules occupy a vertical position, and light does not pass through the external polarizing filter.

Switching on puts the molecules in a perpendicular position, and the external filter ceases to be a hindrance: the light flux passes freely.

The key features of this technology are as follows.

• Pros:
  • bright and saturated colors due to improved contrast, black color is always black (can be used in professional graphics);
  • large viewing angle up to 178°.
• Minuses:
  • response time has increased due to the fact that the electrodes are now located only on one side (critical for gaming applications);
  • high price.
• dead pixel at the same time, it always has a black color (if there is no voltage on the electrodes, then the light filter is always closed).

As can be seen from the list, all the disadvantages and advantages of IPS are symmetrical to TN. This further confirms the reason for its appearance: the technology is a compromise and was intended to eliminate the key disadvantages of its predecessor. Today, in addition to the IPS name used by Hitachi, you can find the name SFT (super fine TFT) for it, which is used by NEC.

Dead pixels, no matter what they are (white or black) not classified as pluses or minuses. It's just a feature. If the pixel is white, then this may not be very annoying when processing texts on a light background, but it is inconvenient when viewing dark scenes. Black is the opposite: it will not be noticeable on dark scenes. Be that as it may, the type of failure - a dead pixel - is always a minus, but it can be different on different matrices.

Varieties of IPS matrices

In order to improve the key characteristics of monitor screens, types of IPS matrices.

• Super - IPS (S-IPS). Thanks to the implementation of overdrive technology, the contrast is improved and the response time is reduced. In its Advanced super-IPS (AS-IPS) modification, its transparency has been further improved.
• Horizontal - IPS (H - IPS). Used in professional graphic applications. The Advanced True Wide Polarizer technology has been applied, making the color uniformity across the entire surface more uniform. Contrast has also been improved and white color has been optimized. Reduced response time.
• Enhanced IPS (e-IPS). Expanded the aperture of open pixels. This helps to use cheaper backlight bulbs. In addition, the response time is reduced to 5ms (very close to the TN level). S-IPS 2 is its improvement. Reduced negative pixel glow effect.
• Professional IPS (P - IPS). The number of colors has been significantly expanded, the number of potential positions of subpixels has been increased (by 4 times).
• Advanced high performance IPS (AH-IPS). In this development, the resolution and the number of dots per inch have increased. At the same time, power consumption has become lower and brightness has been increased.

It is worth noting separately PLS matrix (Plane to line switching), which is developed by Samsung. The developer did not provide technical description of its technology. The matrices were examined under a microscope. No differences were found between PLS and IPS. Since the principles for constructing this matrix are similar to IPS, it is often distinguished as a variety, and not an independent offshoot. In PLS, pixels are denser, brightness and power consumption are better. But at the same time they are significantly inferior in color gamut.

Monitor choice: TN or IPS

Screens built on TN and IPS technologies are by far the most common and cover almost the entire spectrum of needs of the budget and, in part, the professional market. There are other types of matrices VA (MVA, PVA), AMOLED (with illumination of each pixel). But they are still so expensive that their distribution is small.

Color reproduction and contrast

IPS monitors have much better contrast than TN. At the same time, it is very important to understand: if the whole picture is completely dark or light, then such contrast is just the possibility of backlighting. Often, manufacturers with uniform fills simply dim the light of the backlight lamps. To verify the quality of the contrast, you should display a checkerboard fill on the screen and check how much the dark areas will differ from the light ones. As a rule, the contrast in such tests becomes less than 30-40 times. A checkerboard contrast value of 160:1 is an acceptable result.

Color reproduction of IPS screens is carried out practically without distortion, unlike TN. The higher the contrast, the richer the picture on the screen. This can be useful not only when working with photo and video processing programs, but also when watching movies. But there are improved versions of TN matrices, for example, Apple's Retina, which practically do not lose color reproduction.

Viewing angle and brightness

Perhaps this parameter is one of the first, which shows advantages of IPS compared to its cheaper competitor. It reaches 170 - 178 °, while in the improved version - "TN + film" it is in the range of 90 - 150 °. In this parameter, IPS wins. If you watch TV at home with a small company, then this is not critical, but for the case of smartphones, when you want to show something to someone on the screen, the distortion will be significant. Therefore, IPS-type matrices are most often used on them.

In terms of brightness characteristics, IPS screens also win. Large values ​​of brightness and TN matrices make the picture just whitish without black shades.

Response time and resource consumption

A very important criterion, especially if the user often plays applications with dynamically changing scenes. For screens based on the TN matrix, this parameter reaches 1 ms, while the best and most expensive versions of S-IPS have only 5 ms. Although this result is good for IPS. If a high FPS is important to the user and he does not want to contemplate trails from objects, then the choice should be stopped on a TN type matrix.

In addition to the speed of changing the picture, TN screens have two more advantages: low cost and low power consumption.

Touch screen and mobile devices

Recently, devices with capacitive touch screens. As a rule, they are equipped with IPS matrices due to the high number of dots per inch. The higher the dot density, the smoother the fonts on the tablet screen are (even the pixels are indistinguishable to the eye). When using TN matrices in smartphones or tablets, the graininess of the picture will be very noticeable. In monitors and TVs, this parameter is not critical.

Touch coverage, as a rule, is equipped with devices where a touchscreen is needed. Since most often TN matrices are taken because of their cheapness, then such an expensive attribute as a capacitive screen on an average budget monitor with a resolution of 24 inches will simply be a waste of money. While on a small surface area of ​​a tablet or smartphone (up to 6 inches), a capacitive screen is a must.

It's because of the cheapness factor. TN matrix from IPS can be distinguished by pressing: when you press the TN screen, the picture under the finger and around begins to blur in waves with a spectral gradient. Therefore, when choosing mobile device the choice in favor of IPS in this parameter is simply obvious.

Outcome

Choosing a Monitor or TV, the user may still wonder if he should spend money on an IPS screen. The screen surface area of ​​such devices is preferred to take from 24 inches and above. As a result, an expensive and energy-intensive matrix may not justify its investment if professional graphics work is not planned. In addition, if the monitor is needed for dynamic computer games, then a TN matrix would be preferable.

The advantage of an IPS matrix when purchasing a mobile device is undeniable: a smartphone or tablet. High pixel density, high-quality color reproduction and high contrast - all these qualities will help you use the screen both in the sun and indoors. Comparison of monitors for graphics will always be in favor of IPS. Such investments will justify themselves and will be less than the purchase of more expensive devices on VA matrices.

Also, all laptop displays use matrices with 18-bit color (6 bits per RGB channel), 24-bit is emulated by flickering with dithering.

At first, small LCD displays (with a short service life) were used in watches, calculators, indicators, etc.

Large screens have become widely used with the proliferation of laptops and notebooks that are gaining demand.

Specifications

The most important characteristics of LCD displays:

• Matrix type - the technology by which the LCD is made.
• Matrix class - according to ISO 13406-2 are divided into four classes.
• Resolution - horizontal and vertical dimensions, expressed in pixels. Unlike CRT monitors, LCDs have one fixed resolution, the rest being achieved by interpolation. (CRT monitors also have fixed amount pixels, which are also made up of red, green, and blue dots. However, due to the peculiarities of the technology, there is no need for interpolation when outputting a non-standard resolution).
• Dot size (pixel size) - the distance between the centers of adjacent pixels. Directly related to physical resolution.
• Screen aspect ratio (proportional format) - ratio of width to height (5:4, 4:3, 3:2 (15÷10), 8:5 (16÷10), 5:3 (15÷9), 16: 9 etc.)
• Visible diagonal - the size of the panel itself, measured diagonally. The display area also depends on the format: a 4:3 monitor has a larger area than a 16:9 monitor with the same diagonal.
• Contrast - the ratio of the brightness of the lightest and darkest points at a given backlight brightness. Some monitors use an adaptive backlight level using additional lamps, and the contrast figure given for them (called dynamic) does not apply to a static image.
• Brightness - The amount of light emitted by a display, usually measured in candela per square meter.
• Response time - the minimum time required for a pixel to change its brightness. It is made up of two values:
  • Buffer time ( input lag). A high value interferes with fast-paced games; usually silent; measured by comparison with a kinescope in high-speed shooting. Now (2011) within 20-50ms; in some early models it reached 200 ms.
  • Switching time - it is indicated in the characteristics of the monitor. A high value degrades video quality; measurement methods are ambiguous. Now practically in all monitors the declared switching time is 2-6 ms.
• Viewing angle - the angle at which the drop in contrast reaches the specified, for different types matrices and by different manufacturers calculated differently and often cannot be compared. Some manufacturers indicate in those. parameters of their monitors viewing angles such as: CR 5:1 - 176/176°, CR 10:1 - 170/160°. The abbreviation CR (contrast ratio) denotes the level of contrast at the specified viewing angles relative to the perpendicular to the screen. At viewing angles of 170°/160°, the contrast in the center of the screen is reduced to a value of at least 10:1, at viewing angles of 176°/176° - at least to a value of 5:1.

Device

Sub-pixel color LCD

Structurally, the display consists of an LCD matrix (a glass plate, between the layers of which liquid crystals are located), light sources for illumination, a contact harness and a frame (case), more often plastic, with a metal frame of rigidity.

Each pixel of the LCD matrix consists of a layer of molecules between two transparent electrodes, and two polarizing filters, the polarization planes of which are (usually) perpendicular. If there were no liquid crystals, then the light transmitted by the first filter would be almost completely blocked by the second filter.

The surface of the electrodes in contact with liquid crystals is specially treated for the initial orientation of the molecules in one direction. In the TN matrix, these directions are mutually perpendicular, so the molecules line up in a helical structure in the absence of stress. This structure refracts light in such a way that before the second filter its polarization plane rotates and the light passes through it without loss. Apart from the absorption of half of the unpolarized light by the first filter, the cell can be considered transparent.

If a voltage is applied to the electrodes, then the molecules tend to line up in the direction of the electric field, which distorts the helical structure. In this case, the elastic forces counteract this, and when the voltage is turned off, the molecules return to their original position. At a sufficient field strength, almost all molecules become parallel, which leads to the opacity of the structure. By varying the voltage, you can control the degree of transparency.

If a constant voltage is applied for a long time, the liquid crystal structure may degrade due to ion migration. To solve this problem, an alternating current is applied or a change in the polarity of the field with each addressing of the cell (since the change in transparency occurs when the current is turned on, regardless of its polarity).

In the entire matrix, it is possible to control each of the cells individually, but as their number increases, this becomes difficult, as the number of required electrodes increases. Therefore, addressing by rows and columns is used almost everywhere.

The light passing through the cells can be natural - reflected from the substrate (in LCD displays without backlight). But more often used, in addition to independence from external lighting, this also stabilizes the properties of the resulting image.

On the other hand, LCD monitors also have some drawbacks, often fundamentally difficult to eliminate, for example:

OLED (organic light-emitting diode) displays are often considered a promising technology that can replace LCD monitors, but it has met with difficulties in mass production, especially for large diagonal matrices.

Technology

The main technologies in the manufacture of LCD displays: TN + film, IPS (SFT, PLS) and MVA. These technologies differ in the geometry of surfaces, polymer, control plate and front electrode. Great importance have the purity and type of polymer with the properties of liquid crystals used in specific developments.

The response time of LCD monitors designed using SXRD technology (eng. Silicon X-tal Reflective Display - silicon reflective liquid crystal matrix), reduced to 5 ms.

TN+film

TN + film (Twisted Nematic + film) is the simplest technology. Word film in the technology name means extra layer, used to increase the viewing angle (approximately - from 90 to 150 °). At present, the film prefix is ​​often omitted, calling such matrices simply TN. A way to improve contrast and viewing angles for TN panels has not yet been found, and the response time for this type of matrix is this moment one of the best, but the contrast level is not.

The TN + film matrix works like this: if no voltage is applied to the sub-pixels, the liquid crystals (and the polarized light they pass through) rotate relative to each other by 90° in a horizontal plane in the space between the two plates. And since the direction of polarization of the filter on the second plate makes exactly a 90° angle with the direction of polarization of the filter on the first plate, light passes through it. If the red, green, and blue sub-pixels are fully illuminated, a white dot will form on the screen.

The advantages of the technology include the shortest response time among modern matrices, as well as low cost. Disadvantages: the worst color reproduction, the smallest viewing angles.

IPS (SFT)

AS-IPS (Advanced Super IPS- extended super-IPS) - was also developed by Hitachi Corporation in 2002. The main improvements were in the contrast level of conventional S-IPS panels, bringing it closer to that of S-PVA panels. AS-IPS is also used as the name for NEC's monitors (eg NEC LCD20WGX2) based on the S-IPS technology developed by the LG-Philips consortium.

H-IPS A-TW (Horizontal IPS with Advanced True Wide Polarizer ) - developed by LG.Philips for NEC Corporation. It is an H-IPS panel with a TW (True White) color filter to make the white color more realistic and increase viewing angles without image distortion (the effect of glowing LCD panels at an angle is excluded - the so-called "glow effect") . This type of panel is used to create high quality professional monitors.

AFFS (Advanced Fringe Field Switching , unofficial name - S-IPS Pro) - a further improvement of IPS, developed by BOE Hydis in 2003. The increased power of the electric field made it possible to achieve even greater viewing angles and brightness, as well as to reduce the interpixel distance. AFFS-based displays are mainly used in tablet PCs, on matrices manufactured by Hitachi Displays.

Development of NEC's Super Fine TFT Technology

Name	Short designation	Year	Advantage	Notes
Super Fine TFT	SFT	1996	Wide viewing angles, deep blacks	. With the improvement of color reproduction, the brightness became slightly lower.
Advanced SFT	A-SFT	1998	Best response time	The technology evolved to A-SFT (Advanced SFT, Nec Technologies Ltd. in 1998), greatly reducing the response time.
Super-Advanced SFT	SA-SFT	2002	High transparency	SA-SFT developed by Nec Technologies Ltd. in 2002, improved transparency by a factor of 1.4 compared to A-SFT.
Ultra-Advanced SFT	UA-SFT	2004	High transparency Color reproduction High contrast	Allowed to achieve 1.2 times greater transparency compared to SA-SFT, 70% coverage of the NTSC color range and increased contrast.

Development of IPS technology by Hitachi

Name	Short designation	Year	Advantage	Transparency/ Contrast	Notes
Super TFT	IPS	1996	Wide viewing angles	100/100 A basic level of	Most panels also support True Color (8-bits per channel). These improvements come at the cost of slower response times, initially around 50ms. IPS panels were also very expensive.
Super IPS	S-IPS	1998	No color shift	100/137	IPS has been supplanted by S-IPS (Super-IPS, Hitachi Ltd. in 1998), which inherits all the benefits of IPS technology while reducing response time
Advanced Super-IPS	AS-IPS	2002	High transparency	130/250	AS-IPS, also developed by Hitachi Ltd. in 2002, mainly improving the contrast ratio of traditional S-IPS panels to a level where they are second only to some S-PVAs.
IPS Provectus	IPS Pro	2004	High contrast	137/313	IPS Alpha panel technology with wider colors and a contrast ratio comparable to that of PVA and ASV displays without corner glow.
IPS alpha	IPS Pro	2008	High contrast		The next generation of IPS-Pro
IPS alpha next generation	IPS Pro	2010	High contrast		Hitachi transfers technology to Panasonic

Development of IPS technology by LG

Name	Short designation	Year	Notes
Super IPS	S-IPS	2001	LG Display remains one of the top manufacturers of panels based on Hitachi Super-IPS technology.
Advanced Super-IPS	AS-IPS	2005	Improved contrast with a wider color gamut.
Horizontal IPS	H-IPS	2007	Even greater contrast and a visually more uniform screen surface have been achieved. Also, the Advanced True Wide Polarizer technology based on the NEC polarizing film has additionally appeared, to achieve wider viewing angles, eliminating flare when viewed from an angle. Used in professional graphics work.
Enhanced IPS	e-IPS	2009	It has a wider aperture to increase light transmission with fully open pixels, which allows the use of cheaper-to-manufacture backlights with lower power consumption. Improved diagonal viewing angle, response time reduced to 5ms.
Professional IPS	P-IPS	2010	Provides 1.07 billion colors (30-bit color depth). More possible subpixel orientations (1024 vs 256) and better true color depth.
Advanced High Performance IPS	AH-IPS	2011	Improved color reproduction, increased resolution and PPI, increased brightness and reduced power consumption.

MVA/PVA

Matrices MVA/PVA (VA - short for vertical alignment - vertical alignment) are considered a compromise between TN and IPS, both in terms of cost and consumer properties.

MVA technology ( Multi-domain Vertical Alignment ) was developed by Fujitsu as a compromise between TN and IPS technologies. Horizontal and vertical viewing angles for matrices MVA are 160 ° (on modern monitors up to 176-178 °), while thanks to the use of acceleration technologies (RTC), these matrices are not far behind TN + Film in terms of response time. They significantly exceed the characteristics of the latter in terms of color depth and fidelity.

MVA is the successor to VA technology introduced in 1996 by Fujitsu. The liquid crystals of the VA matrix, when the voltage is off, are aligned perpendicular to the second filter, that is, they do not transmit light. When voltage is applied, the crystals rotate 90° and a bright dot appears on the screen. As in IPS-matrices, pixels do not transmit light in the absence of voltage, therefore, when they fail, they are visible as black dots.

The advantages of MVA technology are the deep black color (when viewed perpendicularly) and the absence of both a helical crystal structure and a double magnetic field. Disadvantages of MVA in comparison with S-IPS: loss of detail in the shadows with a perpendicular view, the dependence of the color balance of the image on the angle of view.

The analogues of MVA are technologies:

• PVA ( Patterned Vertical Alignment) from Samsung.
• Super PVA from Sony-Samsung (S-LCD).
• Super MVA by CMO.

pls

PLS matrix ( Plane-to-Line Switching) was developed by Samsung as an alternative to IPS and first demonstrated in December 2010. This matrix is ​​expected to be 15% cheaper than IPS.

Advantages:

• higher pixel density than IPS (and similar to *VA/TN);
• high brightness and good color reproduction;
• large viewing angles;
• full coverage of the sRGB range;
• low power consumption comparable to TN.

Flaws:

• response time (5-10 ms) comparable to S-IPS, better than *VA, but worse than TN;
• lower contrast (600:1) than all other types of matrices;
• uneven lighting.

Backlight

By themselves, liquid crystals do not glow. In order for the image on the liquid crystal display to be visible, you need. The source can be external (for example, the Sun) or built-in (backlight). Typically, built-in backlight lamps are located behind the liquid crystal layer and shine through it (although there are also side lights, for example, in watches).

External lighting

Monochrome displays of wristwatches and mobile phones uses ambient light most of the time (from the Sun, room lights, etc.). Typically, behind the liquid crystal pixel layer is a specular or matte reflective layer. For use in the dark, such displays are equipped with side illumination. There are also transflective displays, in which the reflective (specular) layer is translucent and the backlights are placed behind it.

Incandescent lighting

In the past, some monochrome LCD wristwatches used a subminiature incandescent light bulb. But due to the high energy consumption, incandescent lamps are disadvantageous. In addition, they are not suitable for use, for example, in televisions, as they generate a lot of heat (overheating is harmful to liquid crystals) and often burn out.

Electroluminescent panel

The monochrome LCD displays of some clocks and gauges use an electroluminescent panel for backlighting. This panel is a thin layer of crystalline phosphorus (for example, zinc sulfide), in which electroluminescence occurs - glow under the action of a current. It usually glows greenish-blue or yellow-orange.

Illumination by gas-discharge ("plasma") lamps

During the first decade of the 21st century, the vast majority of LCD displays were backlit by one or more gas discharge lamps (most commonly cold cathode - CCFL, although EEFL has also recently come into use). In these lamps, the light source is a plasma that occurs when an electrical discharge through a gas. Such displays should not be confused with plasma displays, in which each pixel itself glows and is a miniature HID lamp.

Light emitting diode (LED) backlight

In the early 2010s, LCD displays that are backlit by one or a small number of light-emitting diodes (LEDs) became widespread. Such LCD displays (often referred to in the trade as LED TVs or LED displays) should not be confused with true LED displays, in which each pixel glows on its own and is a miniature LED.

Manufacturers

Chi Mei Innolux Corporation (Chimei Innolux) Chunghwa Picture Tubes (CPT)

Envision Hydis

Toshiba Matsushita Display Technology (TMD)

see also

• Industrial LCD

Notes

Literature

• S. P. Miroshnichenko, P. V. Serba. LCD device. Lecture 1
• Mukhin I. A. How to choose an LCD monitor? Computer Business Market No. 4(292), January 2005, pp. 284-291.
• Mukhin I. A. Development of liquid crystal monitors BROADCASTING Television and radio broadcasting: Part 1 - No. 2(46) March 2005. P. 55-56; Part 2 - No. 4(48) June-July 2005. S. 71-73.
• Mukhin I. A.

IPS technology has already entered the modern life. Of course, there are still various competitors such as TN and plasma panels. However, this technology has great potential. No wonder many manufacturers of monitors and TVs prefer this type of matrix. On the shelves of modern stores, monitors with this type of display are increasingly common. In this regard, users have a question, IPS matrix, what is it, and what advantages does it have?

Despite the fact that the IPS matrix has received such distribution only in our time, the technology itself is already quite old. Back in 1995, Hitachi developed the first In-Plane Switching (IPS) matrix. The main goal of the development was to get rid of the shortcomings that TN + Film matrices had.

The new matrix (IPS) had large viewing angles and significantly higher color quality. However, due to certain structural features of the IPS matrix, the response time could not be significantly improved. Of course, the developers have brought this indicator to an acceptable level, however, when compared with TN matrices, the latter have an advantage.

IPS technology got its name due to the fact that the liquid crystal molecules in the cells of the matrix are always located in the same plane and are always parallel to the plane of the panel. This solution allowed to significantly increase viewing angles and color reproduction, which brought LCD displays to a new level.

1. Types of IPS matrices

Over the years, IPS technology has undergone a lot of improvements, which have not only made it possible to achieve higher image clarity and fidelity, but also improved response time and increased screen resolution. This, in turn, improved the image quality. To date, there are several main types of IPS matrices:

• S-IPS (Super-IPS). S-IPS matrix was developed back in 1998. It allowed to significantly increase the contrast of the image and improve the response time.
• AS-IPS (Advanced Super-IPS). The technology was studied in 2002. It allowed to increase the brightness of the picture, as well as further increase the contrast. Of course, this directly affected the improvement in image quality.
• H-IPS (Horisontal-IPS). This type of IPS matrix was developed in 2007. main goal The development of this technology was to achieve an even greater increase in contrast and optimization of white color. This made the image more natural and realistic. This type of matrix quickly found recognition among professional photo editors, as well as designers and fashion designers who were engaged in image processing.
• R-IPS (Professional-IPS). P-IPS matrix was released in 2010. This technology allowed to increase the number of displayed colors and shades to 1.07 billion. It did given type matrices one of the best in the world. In addition, P-IPS matrices have improved response time. Of course, you have to pay for such quality. It is worth noting that this type of matrix is ​​professional, and also one of the most expensive.
• E-IPS (Enhanced-IPS). Matrix 2009. New technologies have improved response times as well as transparency. This, in turn, made it possible to use cheaper and less powerful lamps for backlighting, which reduced energy consumption, turning such screens into more economical devices. However, this decision is not the best way reflected in the quality of the image.
• S-IPS II. One of the latest developments. This type of matrix is ​​a separate branch of IPS technology.
• The latest and newest type of AH-IPS matrix. This technology was developed in 2011 and is considered the most advanced. Such displays have the most natural color reproduction and the best response among IPS matrices.

Taking into account the variety of IPS technologies, a logical question arises, which IPS matrix is ​​​​better? Of course, the rule applies, the newer the development, the higher the quality it has. However, this rule does not always apply. It all depends on what materials the manufacturer uses.

So, not every TFT AH-IPS matrix has the same high image quality. Accordingly, such displays may have different cost. The higher quality materials and components used to create a monitor (or TV), the higher the quality of the image you can get, and the more expensive the device will cost.

1.1. IPS backlight type

One of the main elements of each LCD matrix is ​​the backlight. There are currently two types of LCD backlights:

• Fluorescent lamps;
• LED (light-emitting diode illumination).

Everything is extremely simple here. Fluorescent lighting is considered obsolete. Today, such displays are becoming rarer. Since 2010 fluorescent lamps successfully superseded by LED backlighting. LED monitors and TVs are the same LCD matrices. The only difference is the backlight, which looks like LEDs.

It is worth noting that such a very simple but effective solution made it possible to eliminate a number of shortcomings of LCD matrices and significantly improve image quality (color reproduction, brightness, contrast, and clarity). IPS LED matrices are the most promising displays that have become widespread among users.

If we talk about the choice, then, of course, it is worth giving preference to IPS LCD matrices with LED backlighting. This is due to the fact that such displays are capable of displaying the most natural colors, while the response time is practically not inferior to TN + Film matrices. This difference is impossible to see with the naked eye, but the image quality of the IPS display is pleasantly surprising.

1.2. Benefits of an IPS matrix

Modern IPS matrices have very high performance. It is worth noting that this type of display is a direct competitor to plasma panels, which are famous for their excellent color reproduction, clarity and image resolution. At the same time, IPS displays have a lower cost, which makes them accessible to more users.

Another advantage of the IPS matrix is ​​its durability. Compared to plasma, the IPS LCD display is designed for a longer service life. And the difference is quite significant.

The concept of “burn-in” of pixels is very common. This is the effect that appears when one picture is displayed for a long time. For example, a desktop screensaver on a computer. It is worth noting that both plasma panels and LCD displays have this drawback. However, if we talk about modern IPS matrices, then this drawback is completely excluded. Moreover, such displays are increasingly being used to make PC monitors.

In general, IPS LCD matrices have a mass undeniable advantages, including affordable cost and excellent image quality. Furthermore, modern technologies allow you to make LCD displays of almost any size. It is for this reason that LCD matrices are in the greatest demand among users.

2. IPS and non-IPS matrix on a tablet: Video

OLED technology remains the quality standard in the display industry. All market players today strive to create flat panels, actively competing with competitors on each of the important characteristics: bigger, thinner, brighter, more productive and cheaper. The last parameter on the list is "cheaper", determined by the structure of demand, and at the moment the forecast is as follows: liquid crystal displays (LCD) will retain their dominant positions in the market for the foreseeable future. Such a conclusion can be drawn after the end of the representative international conference USFPD 2015, hosted by IHS Technology, a technology market research firm.

The colors are impressive, but the price is too high

OLED technology (organic light-emitting diode) can still be considered a major success for image scientists. From the point of view of the management of manufacturing companies, this direction remains one of the main disappointments; profits here are still very modest. Brings too high OLED screens and short term services. It is not possible to significantly increase the active life of the blue layer of diodes (for each of the three primary colors - red, yellow and blue, separate elements are used).

Familiar to all LCD displays, by all accounts, should be forced out of the market as soon as the developers of OLED technology cope with the above two problems. LCD screens are relatively easy to manufacture, although they are noticeably inferior in color reproduction quality. However, the forecast for today is this: LCD displays with a low pixel density will be the most mass product. Screens made using LTPS (low-temperature poly-silicon) technology, also known as Retina, will retain their second position in the list. This solution allows you to fit more pixels per inch.

Today it is difficult to predict the future of technology using semiconductor nanocrystals, known as "quantum dots" (quantum dots). These components can significantly improve the color reproduction of LCD displays. If you believe the statements of representatives of the company QD Vision, the use of quantum dots will achieve a result as close as possible to the ideal 100% color according to the tests of the NTSC agency.

A simple dot-backlit LCD can typically display no more than 70% of the NTSC standard. The head of marketing at QD Vision, John Volkmann, says that only the use of quantum dot technology will improve the quality of color reproduction. This opinion seems very convincing, in favor of the excellent prospects for quantum dots technology is also the success of Nanosys Inc., which has entered into a major deal with Samsung. Quantum dots produced by Nanosys are used in TVs and monitors of the elite SUHD line from the South Korean giant.

There are others possible solutions The problem of pixel density in LED-backlit LCD screens is an important issue that many industry engineers are working on today.

Expanding the dynamic range (High Dynamic Range, or: "bright - brighter, dark - darker") remains the main trend in the development of the direction of production of displays for high-definition television and screens intended for outdoor use. The well-known problem of glare in outdoor displays is solved using the method of transflection, or the reflection of sunlight from the mirror surface of the back panel.

Other trends

According to statistics, the average size of TV screens sold in the world is growing by about one inch every year. Similar figures are given by smartphone market researchers, the screen size of pocket gadgets continues to grow and will probably reach 7 inches soon. Such a device will be problematic to store in your pocket. In order to avoid competition with phablets, we can also expect an increase in the average screen diagonal in the tablet segment.

However, these forecasts should not be overly trusted. It is known that consumer demand is subject to periodic changes in fashion, and perhaps over time small screens will return en masse. Be that as it may, the category of small and medium displays (less than 10 inches) remains the hottest segment of the market today.

Curved displays - still out of the race

Discussion of perspectives flexible displays the press does not subside, although this very interesting solution remains a task for the future due to too high production costs. You can remember, except perhaps the experience of Samsung, which successfully released smartphones with a curved screen edge.

Good news from Corning, a manufacturer of glass of all kinds, from microwave cookware to optical fiber. A new grade of glass, "Lotus", is being prepared for release, which will provide support for better resolution (up to 100 additional pixels per inch).

It is noteworthy that the need to meet the demand for the growing diagonal of TV screens from year to year, Corning is forced to start building another plant.

Touch capabilities of displays

Sri Peruvemba, spokesman for an association called the Society of Information Display, argued during his conference talk that more and better touch screens would soon be required. Wearable devices such as smartwatches need displays that continue to respond reliably to touch when the surface gets wet or in cold temperatures. We are not talking about new technology here, there are ready-made solutions, they are simply more expensive at cost.

In addition, according to Peruvemba, the direction known as “Haptic language” needs to be standardized. This category includes such methods of communication with touch devices like vibration. If it is possible to develop common standards, then we can expect an acceleration of development in this area, where so far we can only recall a set of options implemented in the Apple Watch smart watch.

Conclusion

The cost of large flat panels is likely to stabilize for a while. After last year's frightening drop in prices, market players are struggling to maintain the profitability of their mass-market factories. The situation is better for those companies that have established themselves in the elite segment. So, Panasonic, which successfully sells its TX-65CZ950 OLED TVs at a price of $10,000, can afford the minimum by selling "budget" models.

It doesn't take Vanga's ability to predict other trends in the flat screen industry. The consumer wants to buy even brighter, more productive, wide, thin and inexpensive displays, which means that manufacturing companies will continue to follow demand.

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