OLED vs LCD: Differences, Advantages and Disadvantages Explained. Problems of OLED screens that hinder their promotion

Operating principle

To create organic light-emitting diodes (OLEDs), thin-film multilayer structures consisting of layers of several polymers are used. When a voltage positive relative to the cathode is applied to the anode, a flow of electrons flows through the device from the cathode to the anode. Thus, the cathode gives electrons to the emissive layer, and the anode takes electrons from the conducting layer, or in other words, the anode gives holes to the conducting layer. The emissive layer receives a negative charge, and the conductive layer receives a positive charge. Under the influence of electrostatic forces, electrons and holes move towards each other and recombine when they meet. This occurs closer to the emissive layer because in organic semiconductors holes have greater mobility than electrons. During recombination, a decrease in the energy of the electron occurs, which is accompanied by the release (emission) of electromagnetic radiation in the region of visible light. That is why the layer is called emissive. The device does not work when a voltage negative relative to the cathode is applied to the anode. In this case, holes move towards the anode and electrons move in the opposite direction towards the cathode, and no recombination occurs.
The anode material is usually indium oxide doped with tin. It is transparent to visible light and has high performance exit, which promotes the injection of holes into the polymer layer. Metals such as aluminum and calcium are often used to make the cathode because they have a low work function that facilitates the injection of electrons into the polymer layer.

Classification by control method

There are two types of OLED displays - PMOLED and AMOLED. The difference lies in the way the matrix is controlled - it can be either a passive matrix (PM) or an active matrix (AM).

In PMOLED-Displays use controllers for scanning the image into rows and columns. To light a pixel, you need to turn on the corresponding row and column: at the intersection of the row and column, the pixel will emit light. In one clock cycle you can make only one pixel glow. Therefore, to make the entire display light up, you need to very quickly send signals to all the pixels by cycling through all the rows and columns. How is it done in old CRTs (cathode ray tubes).

PMOLED-based displays are cheap, but due to the need for horizontal scanning of the image, it is not possible to obtain large displays with acceptable image quality. Typically, PMOLED display sizes do not exceed 3" (7.5 cm)

In AMOLED In displays, each pixel is controlled directly, so they can quickly reproduce the image. AMOLED displays can be large in size and displays as large as 40" (100 cm) have already been created. AMOLED displays are expensive to produce due to the complex pixel control circuitry, unlike PMOLED displays where a simple controller is sufficient for control.

Classification by light-emitting material

Currently, two technologies are mainly being developed that have shown the greatest efficiency. They differ in the organic materials used: micromolecules (sm-OLED) and polymers (PLED), the latter are divided into simply polymers, polymer-organic compounds (POLED), and phosphorescent (PHOLED). Let's talk a little more about the latter. PHOLEDs use the principle of electrophosphorescence to convert up to 100% of electrical energy into light. For example, traditional fluorescent OLEDs convert approximately 25-30% of electrical energy into light. Due to their extremely high level of energy efficiency, even compared to other OLEDs, PHOLEDs are being studied for potential use in large displays such as television monitors or screens for lighting needs. Interestingly, OLED technology can significantly improve the quality of LCD panels, since PHOLED (PHosphorescent Organic Light Emitting Diode) technology is a promising backlight technology for them. According to Universal Display Corporation, the use of PHOLED diodes increases the brightness of panels by four times.

Schemes of color OLED displays
OLED displays based on micromolecules were the first to appear, but they turned out to be too expensive because they were produced using vacuum deposition.

The first step towards creating polymer displays was made in 1989, when scientists at the University of Cambridge managed to synthesize a special polymer - polyphenylene vinylene. Displays of this type can be obtained by applying polymer materials to a base with a special inkjet printer. Sometimes such displays are called LEP (Light-Emitting Polymer). The base can be flexible with a bending radius of 1 cm or less.

However, today micromolecule-based devices are ahead of LEP devices in terms of service life and efficiency. Comparative characteristics The durability and emission efficiency for the two OLED display technologies are given below.

There are three schemes for color OLED displays:

* circuit with separate color emitters;
* WOLOD+CF circuit (white emitters + color filters);
* scheme with conversion of short-wave radiation.

The simplest and usual option– a regular three-color model, which in OLED technology is called a model with separate emitters. Three organic materials emit light of basic colors - R, G and B. This option is the most efficient in terms of energy use, however, in practice it turned out to be quite difficult to select materials that will emit light with the desired wavelength, and even with the same brightness.

The second option is much simpler to implement. It uses three identical white emitters that emit through colored filters, but it is significantly inferior in energy efficiency to the first option, since a significant part of the emitted light is lost in the filters.

The third option (CCM - Color Changing Media) uses blue emitters and specially selected luminescent materials to convert short-wavelength blue radiation into longer wavelengths - red and green. The blue emitter naturally emits “directly”. Each option has its own advantages and disadvantages:

Other types of OLED displays

TOLED- transparent light-emitting devices TOLED (Transparent and Top-emitting OLED) - a technology that allows you to create transparent (Transparent) displays, as well as achieve a higher level of contrast.
Transparent TOLED displays: The direction of light emission can be up only, down only, or both directions (transparent). TOLED can significantly improve contrast, which improves display readability in bright sunlight.
Since TOLEDs are 70% transparent when turned off, they can be mounted directly on a car windshield, on store displays or for installation in a helmet virtual reality... Also, the transparency of TOLEDs allows them to be used with metal, foil, silicon die and other opaque substrates for forward-display displays (can be used in future dynamic credit cards). Screen transparency is achieved by using transparent organic elements and materials for the manufacture of electrodes.
By using a low reflectance absorber for the TOLED display substrate, the contrast ratio can be an order of magnitude superior to LCDs (mobile phones and military fighter aircraft cockpits). Using TOLED technology, it is also possible to produce multilayer devices (for example SOLED) and hybrid matrices (Bidirectional TOLED TOLED makes it possible to double the displayed area with the same screen size - for devices in which the desired amount of displayed information is wider than the existing one).

FOLED (Flexible OLED) - main feature- flexibility of the OLED display (Demonstration of a flexible OLED display from SONY). Uses plastic or flexible metal plate as a substrate on one side, and OLED cells and sealed thin protective film- on the other. The advantages of FOLED: ultra-thin display, ultra-low weight, strength, durability and flexibility, which allows OLED panels to be used in the most unexpected places. (Space for imagination - the area of possible application of OLED is very large).
Staked OLED- a fundamentally new solution from UDC – Staked OLED, folded OLED devices. The main feature of the new technology is the placement of R-cells (G-, B-) in a vertical (series) rather than a horizontal (parallel) plane, as happens in an LCD display or a cathode ray tube. In SOLED, each subpixel element can be controlled independently. The color of a pixel can be adjusted by changing the current passing through the three color elements (non-color displays use pulse width modulation). Brightness is controlled by changing the current. Advantages of SOLED: high density filling the display with organic cells, thereby achieving good resolution, which means a high-quality picture. (SOLED displays have 3 times improved image quality compared to LCD and CRT).

Advantages compared to LCD displays

* smaller dimensions and weight
* no need for backlighting
* absence of such a parameter as viewing angle - the image is visible without loss of quality from any angle
* instant response (an order of magnitude lower than that of LCD) - essentially a complete absence of inertia
* better color rendering (high contrast)
* lower power consumption at the same brightness
* possibility of creating flexible screens

Brightness. OLED displays provide radiation brightness from a few cd/m2 (for night work) to very high brightness - over 100,000 cd/m2, and their brightness can be adjusted over a very wide range dynamic range. Since the life of the display is inversely proportional to its brightness, it is recommended for devices to operate at more moderate brightness levels up to 1000 cd/m2. When the LCD display is illuminated with a bright beam of light, glare appears, and the picture on the OLED screen will remain bright and saturated at any light level (even with a direct hit sun rays to the display).

Contrast. Here OLED is also the leader. OLED displays have a contrast ratio of 1,000,000:1 (LCD contrast ratio 1300:1[unspecified 71 days], CRT 2000:1)
Viewing angles. OLED technology allows you to view the display from any side and at any angle, without losing image quality.
Energy consumption. The energy consumption of OLED displays is one and a half times lower than LCD. The power consumption of PHOLED is even lower.
The need for the benefits demonstrated by organic displays is growing every year. This fact allows us to conclude that humanity will soon see the flourishing of this technology.

But technology does not stand still and a new generation of OLED is ahead

LEDs based on quantum dots. Let us immediately note that the strengths of QDLED devices (Quantum Dot LED - quantum dot LED) are high brightness, low production cost, and a wide range of colors. Almost immediately after the invention of a new type of LEDs, they are predicted to have excellent prospects for becoming the basis for displays of mobile devices (“handhelds”, mobile phones etc.), and even large-format television panels.

By quantum dot, scientists mean a special semiconductor structure that limits the movement of electrons in three dimensions at once. In relation to quantum dot LEDs, the following variation was used: cadmium selenide forms the “core”, and zinc sulfide acts as the limiting “shell”. The main "actors" in in this case are electrons, which, when transitioning from a high energy state to a lower one, emit photons, due to which the glow of the point is formed. The mechanism for changing the color of the LED glow is also quite simple - you just need to change the size of the quantum dot, which leads to a change in the wavelength of the light. Thus, by calculating the required dimensions of the semiconductor structure, it is possible to create LEDs in red, orange, yellow, or green colors. Another advantage of the devices is the highest brightness - up to 9000 cd/sq. m. For example, the brightness of modern displays does not exceed 500 cd/sq. m. That is, the development makes it possible to increase the corresponding parameter by an order of magnitude. Moreover, the technology makes it easy to increase the brightness of LEDs - just by forming a few quantum dots.

At the end I am posting a video to compare the properties of TFT and OLED displays.

Electronic devices with displays have become an integral part of our daily lives, requiring more and more attention. The eyes of millions of people are drawn to the screens of monitors and televisions, tablet PCs and smartphones, photo and video cameras every day. Some work, some play, but everyone wants to see a high-quality image on the display.

Over the past years, LCD technology with LED backlight has held the leadership in the production of matrices. However, OLED technology, based on the ability of organic light-emitting diodes to emit light, continues to “tread on its heels”. What are OLED displays and what prevents them from competing on equal terms with LCD screens?

Operating principle and manufacturing technology

Organic light-emitting diode or OLED for short is semiconductor device, created on the basis of organic compounds, which, when passed through electric current emit visible light. In a single copy, an organic LED is of no practical interest. Therefore, they are combined into matrices to create information display devices.

OLED technology is a process of creating a thin-film structure on which several layers of polymers with different conductivities are applied. The figure shows a vertical section of the OLED structure in a two-layer interpretation. Here, two polymer layers are located between the electrodes (anode and cathode), to which a voltage of the appropriate polarity is applied. In this case, the upper (emissive) layer is filled with electrons emitted by the cathode, which rush to the boundary with the lower (conducting) layer. At the same time, the conductive layer receives a positive charge from the anode, directing holes to the boundary with the upper layer. The boundary of two polymers resembles the p-n junction of a conventional semiconductor, where the recombination process occurs. But in this case, charged particles recombine in the emission layer, which is achieved due to the higher speed of holes in organic structures. As in conventional LEDs, the loss of energy by an electron is accompanied by the emission of photons in the visible wave spectrum. For this reason, the top layer is called emissive.

An organic LED emits light only when the polarity of the supply voltage is observed. If a reverse voltage is applied to the electrodes, then electrons and holes will not recombine. The material for the anode is usually a film of transparent indium oxide, and the material for the cathode is aluminum or calcium.

Main directions

Independent research on the creation of OLED matrices among scientists from different countries contributed to the emergence of LED displays that differ in type and purpose. Each technology has its own practical advantages and, therefore, development prospects.

TOLED (Transparent OLED) – positioned as a transparent organic light-emitting device. Technologically, it is possible to set any direction of radiation, including two-way. TOLEDs are distinguished by a high-contrast image and transparency of the film when turned off, which significantly expands the scope of their application.
FOLED (Flexible OLED) – is implemented by fixing an organic film between flexible electrodes. The electrodes can be either the thinnest aluminum foil or a transparent film borrowed from TOLED. Thus, it is possible to create flexible transparent screens with a wide range of capabilities, placing them on the windshield of cars and airplanes. There are already TVs with curved OLED displays on sale.
SOLED (Stacked OLED) is a structure of vertically stacked organic light-emitting diodes. Each subpixel (blue, red, green) is located on top of each other, which allows you to increase the screen resolution several times. An undeniable feature of SOLED is its color fill factor of 100%. This means that when the screen color is set to red, all pixels will glow only red. Enabling a similar mode in displays with a horizontal structure will turn off blue and green pixels. As a result, so-called gaps will appear, which will become noticeable on large diagonal screens.

It is obvious that the subsequent development of OLED technologies consists of the combined implementation of these techniques and the production of flexible transparent high-contrast displays.

A separate line is worth highlighting OLED white light panels. Their practical implementation is simpler, since it eliminates the need to create separate pixels and control matrices. Using a phosphor you can set any shade, and by changing the current you can adjust the brightness. Large panels can be used as economical ceiling and wall lamps.

Main differences between OLED displays

The main difference between OLED and LCD displays is the absence of a backlight unit. Organic LEDs emit light on their own and do not require an additional light source to form an image. In turn, the image quality of an LCD screen directly depends on the type of backlight and, despite the replacement of fluorescent lamps with more compact LEDs, it is impossible to do without it. Even the thinnest LED backlight consists of SMD LEDs, light guides, reflectors and their attachment points, which naturally affects the thickness, weight, image quality and reliability of the product.

In addition, OLED matrices are credited with lower power consumption, again due to the lack of backlighting. However, this difference is not so significant. To illuminate each organic LED, current must be passed through it. As a result, a 55″ OLED TV consumes about 100 W, which is comparable to the consumption of a similar LCD TV.

An important characteristic of any display is the viewing angle. In OLED screens, this parameter has been brought to perfection, which means that you can look at it from any side, top and bottom, without deteriorating image quality. In LCD panels, a similar result was achieved on IPS matrices. However, it was not possible to completely get rid of distortions.

The contrast of OLED displays is several times higher than that of liquid crystal counterparts, which is explained by two factors. Firstly, there is no additional lighting. Secondly, a switched-off organic LED does not emit anything, which means it is perceived by the eye as an absolutely black dot. The contrast ratio of currently produced TVs is 10,000:1. According to the developers, this is far from the limit.

The OLED display is 1000 times faster than LCD. This is evidenced by a response time of approximately 10 μs. Comparing this value with the capabilities of the human eye, we can safely say that there is no inertia when watching the most dynamic videos.

The brightness of each Organic LED depends on the magnitude of the forward current. By controlling the pixel current, it is possible to achieve the required brightness without loss of quality, which was impossible to implement in LCD technology. Working with an OLED monitor is equally pleasant both at night and in sunny weather. In theory, the brightness of an OLED matrix can exceed 100 thousand cd/m2. But in this mode, the service life of the LEDs is sharply reduced. Therefore, in practice, the brightness is still limited to 1000 cd/m2.

Advantages and disadvantages of OLED technology

Based on the previous section, there are several positive aspects that make OLED displays superior to all previous technologies:

Less weight and size, which is achieved due to the small thickness of the matrix;
- low energy consumption, which will further decrease in the future;
ideal viewing angle;
- lack of backlight;
- contrast, brightness and response time are several orders of magnitude better than LCD;
- the ability to create flexible and transparent screens that will operate stably over a wide temperature range.

Like anyone process, the manufacture of OLED matrices has disadvantages that significantly slow down their mass production. Moreover, the main limiting factor does not depend so much on the imperfection of technology, but is determined by purchasing power.

The second disadvantage is the short continuous operation time of organic LEDs of some colors. But this problem has already been successfully solved, which is confirmed serial production laptops and TVs with OLED matrix from world-famous companies.

The disadvantages include the screen burn-in effect, which occurs due to prolonged display of a static image. The effect is reminiscent of the appearance of a false picture on CRT and plasma monitors. To prevent LEDs from burning out, new matrix models feature a dynamic shift of color pixels that is invisible to the eye.

OLED technology will continue to be improved and refined for several more years, which today can also be called its negative side.

Prospects and scope

There is no doubt that OLED technology will dominate the electronics market. But so far this innovative way of displaying information has to overcome great difficulties associated with the need for large commercial investments. For this reason, some companies have significantly reduced costs or even stopped funding research to create their own OLED matrices. For example, Sony relied on the production of LCD TVs with 4K resolution, considering this approach to be economically justified.

Among those who are not going to give up and continue to improve the quality of OLED displays, the favorites are South Korean LG and Samsung. In the near future, these companies expect to reduce the cost of OLED matrices and become their main suppliers for other manufacturers of electronic equipment.

Already now we can observe the active promotion of “smart” gadgets with small screens. OLED watches, smartphones, netbooks find their buyers, for whom an overpayment of 20-30% is nothing compared to a super high-quality image. Retail price of a 55˝ OLED TV at at the moment 2-2.5 times higher than an LCD TV with the same parameters.

Time will tell how quickly OLED can take over. One thing is certain - OLED market displays will progress every year.

OLED display cost

The most the best manufacturers OLED displays today are LG, Samsung, Sony.

The cost of high-quality OLED displays starts from RUB 165,000/sq.m.

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OLED is an abbreviation that is also used to refer to televisions high class. Therefore, it is important for home entertainment lovers to know what exactly it means. This technology is next stage development of visual display devices that has finally reached a cost where the average consumer can afford it. She offers best quality images (deeper blacks and brighter white colors), lower power consumption and faster response times than traditional TVs.

Market restrictions

So why doesn't everyone know what it is? OLED TVs are prohibitively expensive, and for a very long time, only two companies, LG and Panasonic, used similar technology in their panels. Fortunately, today everything is changing. Sony, one of the first developers of such technology, returned to the game in 2017 with new version receiver TV signal Bravia A1E.

So what are OLED TVs? Are they worth their cost? And what are their benefits?

What is the difference between OLED and LCD/LED?

In everything. Although the acronyms are almost the same, their processes for creating an image are completely different.

What is an OLED TV? This is a matrix of organic light-emitting diodes. The organic part refers to the carbon film that is inside the panel in front of the glass screen. OLED matrices emit their own light when electric current passes, and LCD display cells require an external source, such as a backlight, which ensures the brightness of the image. This distinguishes LCD screens from their LED variants. A traditional LCD display has a backlight (cold cathode fluorescent light, or CCFL) that is uniform across the entire back of the screen.

Thus, lighting of the same brightness is used to create a black or white image. This reduces the number of "hot spots" or areas of extremely bright light. After all, the actual source illuminating them is homogeneous.

A few years ago, engineers from companies such as Samsung and Sony introduced LED matrix. If a certain part of the screen is black, the LEDs behind it can be turned off to make it appear darker.

This best solution than CCFL. But it still has its shortcomings. Because it is behind the LCD, the backlight is not completely synchronized with the pixel in front of it. The result is an effect called "halo". When this occurs, the LED radiation from the bright areas of the image penetrates into the dark areas.

This distinguishes OLED from LED-backlit LCD displays. Their pixels themselves are light sources. So when they need to be black, they can be turned off completely without relying on background lighting.

Image quality

The result is blacks that look unusually dark, and when this is combined with the brightest white OLED panels can achieve, the result is a fantastically bright and contrasty image.

Just about the only consistent OLED TV makers on the planet, LG and Panasonic, like to use the term "infinite contrast" to describe how self-adjusting pixels turn off completely when rendering black, providing "absolute" rather than "relative" depth. It only describes how dark a single pixel can be compared to the brightest area on the screen.

For years, the longevity of OLED panels has been questioned, and production lines have failed to turn a profit due to high failure rates. But as companies like LG have invested heavily in the technology, it has become more accessible, although still much more expensive than competing solutions.

Refresh rate

The benefits of OLED go beyond just static picture quality thanks to the responsiveness and smoothness of the display itself. This means that gamers and home theater enthusiasts will definitely enjoy OLED. The LED screen supports a refresh rate of up to 0.001ms, which is approximately 1000 times faster than a standard LED-backlit LCD panel, and also outperforms today's unused plasma technology.

Other benefits

And since the light source they use has become tiny, the depth of the screen has decreased accordingly. This means OLED TVs have extraordinarily deep black and bright white peaks, improved color reproduction, and offer smooth motion display - all in a form factor that is just a few millimeters deep.

The viewing angles of OLED screens are excellent. Even when viewed from a high angle, the image remains unshakable, the colors are rich and the contrast is excellent.

AMOLED vs OLED

IN cell phones and others portable devices AMOLED screens are often used. AM here stands for "active matrix" and represents the way the display is addressed by the device's electronics. It's just a different way of running an OLED screen that's better suited to conveying motion (like video). Each pixel can be addressed individually, which is what is required on a TV.

Active matrix LCD monitors were called TFT LCDs. Today this is not specifically stated because every LCD display produced on a phone, tablet, TV, etc. is equipped with an active matrix. The same idea applies to LED panels. OLED TVs are a kind of active matrix.

What OLED TVs are currently in production?

OLED panels appeared on the market in 2012, and various manufacturers have been producing them for many years. Previously, OLED screens were produced only by Samsung and LG. But the first of these South Korean companies abandoned the idea due to the high cost and complexity of the technology, and has no plans to restart production anytime soon.

LG OLED TVs have been steadily released over the past few years. In 2016, this company introduced 4 product lines with OLED panels - G6, E6, C6 and B6. And in 2017, it released 5 models - G7, E7, C7, B7 and completely new TV LG OLED 65” W7 with incredibly thin screen and soundbar Dolby Atmos.

Today, fortunately, LG is not completely alone in the market. Panasonic launched its first OLED set, the TX-65CZ950, and followed it up with an impressive line-up of other TVs.

Last but not least is Sony's new (or old?) rival, the Bravia A1E, which looks incredible.

Can OLED reproduce 3D?

3D imaging may have lost its appeal as a TV feature, but that doesn't stop manufacturers from continuing to include support for it in their high-end models.

LG and Panasonic have included 3D as a feature on their 2016 OLED TVs. And in most cases, it's the passive variety, which means cheaper glasses and less screen flicker.

The disadvantage of passive 3D is the drop in resolution. But, fortunately, almost all OLED sets are now equipped with a UHD display, the number of pixels of which is enough to not experience any discomfort. LG OLED TVs of 2017 models do not support three-dimensional image, but this decision is unlikely to disappoint many.

Price of new technology

LED screens are definitely getting cheaper, but they are still difficult to call affordable. Prices for the most inexpensive LG OLED TVs are set at $1,800. Panasonic equipment will cost even more.

Shortage OLED TVs TV on the market means that a small number of manufacturers are more or less free to set the price they want. A drop in value is not expected until it appears larger number competitors.

However, usually when one company starts to move forward, the others quickly catch up. Prices should come down as manufacturers solve production line problems and demand for this phenomenal technology increases.

Perspective

Today it is already obvious that OLED TVs are a technology that, even after several years of intensive development, still remains quite complex and expensive for manufacturers. The fact that it has existed for so long and has not yet reached the level of mass production makes many people think that it has no future.

It is quite obvious that companies have not yet abandoned OLED. This means the opposite. The technology is far from oblivion. But after so many years of trying to get it to work effectively, it's hard to maintain hope that it will ever become truly available.

Chances of success

However, the high cost of OLED does not mean that manufacturers are not able to improve it. The $1,800 price tag isn't exactly budget-friendly, much less $8,000 for the 65" LG OLED65W7 OLED TV, but it's much cheaper than what displays of this type cost just a few years ago. If this trend continues, we can hope that in a couple of years the technology will become dominant. Although it still remains the lot of a few enthusiasts.

OLED (organic light-emitting diode) has been hailed as the future of television technology, promising rich colors including deep blacks and reduced motion blur.

It may seem that the new technology is not much different from the more common LED panels on the market. But the word "organic" implies a difference in the very way images are presented on the screen.

What are the advantages of OLED screens?

LED screen - liquid crystal display with improved LED backlight. In modern LCD TVs, liquid crystals rotate under the influence of electricity and transmit light through every pixel of the image. The light passes through filters (red, blue and green) and when mixed, results in colors ranging from darkest to white. If all the crystals are rotated so as not to allow any of the three colors to pass through, then the output is black.

Crystals have their advantages: low cost, thinness and lightness of materials, but they also have an important drawback - the level of black color. The crystals block the light, but the backlight continues to work. The light falls on the “black” pixels, which makes the dark image faded.

OLED screens do not - each individual pixel emits light independently when an electric current is applied to it. If the pixel does not receive electricity, then we see the absence of light - true black.

Absolutely zero values for color and brightness change the perception of contrast. On an OLED display, even the smallest amount of light in the dark parts of the image appears brighter compared to LED screens. In addition, pixels in OLED screens can change color almost instantly, unlike the delay in LED panels, which take longer to activate and move the crystals.

Another advantage of OLED technology, which stems from black levels and contrast, is realistic, rich colors.

Do pixels burn out on OLED screens?

On older plasma TVs, pixels could burn out in those parts of the screen where for a long time there was something static, such as a channel logo or a video game menu. Traces from such objects could be permanently “imprinted” on the display, so manufacturers added special tools to TV settings so that this could be avoided.

This is not typical for OLED screens, but if a static image is left for several hours at a time, it can “freeze”, leaving a barely noticeable trace, for about an hour, and then disappear completely. Nothing bad will happen to the TV.

How bright are OLED displays?

If it has the Ultra HD Premium sticker, then its pixels must reach a minimum brightness threshold. This value may vary depending on the depth of black. If the black level in an OLED panel is somewhere between 0.0005 and 0.5 cd/m2, then the maximum brightness for such a TV should start from 1,000 cd/m2. But if the screen is capable of even more dark color, then its maximum can start from 540 cd/m2.

The perceived brightness of an OLED TV depends on where you place it, so in a bright room the benefits of an OLED screen won't be as noticeable. Inexpensive OLED panels produce brightness of 700–800 cd/m2, while LED TVs are capable of more - 1,400–1,500 cd/m2.

This year, new models of OLED TVs with brightness of up to 2,000 cd/m2 will appear, but their price is unlikely to please buyers.

With a maximum screen brightness of 800 cd/m2, its advantages over LCD TVs are noticeable at night in low light or during the day with the curtains closed. Once you dim the light, the effect of black on image quality becomes obvious.

However, deep blacks are not a magical force that transforms any film on screen. Sometimes, for example in streaming services, the color black may be coded not as a complete absence of light, but as a lighter version of it.

What are the disadvantages of OLED technology?

As with color quality, motion blur reduction depends on the source content. In theory, OLED technology is superior to LCD and LED standards in conveying motion.

In practice, only specially prepared files and the blur reduction mode lead to noticeable results. Dynamic films with an image frequency of 24 frames per second will not work. At the same time, it is quite difficult to find videos in 4K resolution, with realistic colors and high frequency frames at the same time to justify the purchase of an expensive OLED panel.

Should I buy an OLED TV or not?

So far, for most buyers, the answer is no. If you don't necessarily need support for HDR-10 or Dolby Vision, then you can spend much less money on a 4K LED TV, low level blur and delay input signal. You won't get the richest picture possible, but you will be able, for example, to purchase a good audio system.

If you still want to join the world, then in this case it is better to choose an OLED screen, but you will have to calibrate it correctly. For large rooms, such TVs are not profitable to buy, unless you have more than $20,000 for a 77-inch LG model.

Low blur and bright colors OLED panels are also good for gaming, but it is worth considering the higher input signal latency, which affects the responsiveness of controls and is especially critical in network games. Manufacturers have already begun to solve this problem with firmware updates.

The HDR standard and OLED technologies will surprise you with image quality now, but there is still little content suitable for them.