tft lcd versus led future in stock
Most modern computer monitors, and even televisions, have an edge-lit LCD display that’s fundamentally similar to the first such displays sold decades ago, but that’s not where the future is headed. The twin threats of Mini-LED and OLED want to conquer the world of PC displays for themselves.
Which will win, and where is the future headed? I spoke with Ross Young, CEO of Display Supply Chain Consultants, and David Wyatt, CTO of Pixel Display (and inventor of Nvidia G-Sync), for the inside scoop.
Modern OLED displays rarely exceed 1,000 nits of brightness, and when they do, are incapable of sustaining it. LG’s C9 OLED television, for example, can’t sustain a peak brightness above 160 nits (according to testing by Rtings). Mini-LED displays like Apple’s Liquid Retina XDR, Samsung’s Odyssey Neo G9, and Samsung’s QN90A television can hit peak brightness well above 1,000 nits and sustain at least 600 nits.
Wyatt points to this as a key advantage. The best HDR standards call for up to 10,000 nits of brightness. Current consumer Mini-LED displays don’t achieve this, but it’s possible future displays will.
And Micro-LED, which uses individual LEDs as per-pixel lighting elements, can reach even greater heights. Wyatt says his company’s VividColor NanoBright technology will be capable of reaching up to one million nits.
Such brightness is not necessary for computer monitors or home televisions and instead targets demanding niche components, such as avionics displays. Still, it hints that we’ve only seen a sliver of HDR’s real potential – and that Mini-LED and Micro-LED, not OLED, will lead the charge.
OLED’s greatest strength is the opposite of Mini-LED’s incredible brightness. The self-emissive nature of OLED means each pixel can be turned on or off individually, providing a deep, inky, perfect black level.
“Mini-LED has clear advantages in sources of supply and brightness,” Young said in an email, “but OLEDs have advantages in regards to contrast, particularly off-axis contrast, response times, and no halo effect.” The “halo effect,” also known as blooming, is the halo of luminance that often surrounds bright objects on a Mini-LED display.
The advantages of OLED add up to superior contrast and depth. You’ve likely noticed this when viewing an OLED television at your local retailer. High-quality content has an almost three-dimensional look, as if the display is not a flat panel but a window into another world.
Modern Mini-LED displays often claim to rival OLED. Apple’s Liquid Retina Display XDR, for example, lists a maximum contrast ratio of 1,000,000:1. In reality, Mini-LED still noticeably lags the contrast performance of OLED because it can’t light pixels individually. This will remain true at least until Micro-LED, which can light pixels individually, goes mainstream.
Mini-LED improves on traditional edge-lit LCD displays by improving the backlight. The LCD panel itself, however, is much the same as before and retains some flaws common to the technology.
Display quality can shift significantly depending on viewing angle, and significant blur will be visible when displaying fast motion. Both problems are inherent to LCD technology. The liquid crystals do not block light uniformly, so the image looks different from different angles, and require a few milliseconds to respond to a charge, causing blur or ghosting in rapidly changing images.
OLED is different from LCD technology. There’s no liquid crystals to twist or move. Each pixel is an organic element that creates its own light when a charge is applied. The light is emitted in a relatively uniform pattern and can turn on or off extremely quickly, removing the viewing angle and motion performance issues of LCD entirely.
The last few points—contrast, black levels, viewing angles, and response times—highlight the strengths of OLED technology. But, OLED has a weakness: durability.
Wyatt hammered this point during our conversation. The “O” in OLED stands for organic, and organic material will wear out. Indeed, exposure to light itself (and blue light in particular) wears down OLED, reducing the light produced by pixels over time.
This problem is most often discussed in the context of burn-in or image retention. Burn-in happens when specific pixels on an OLED panel degrade differently from those around them, creating a persistent shadow in the image.
OLED manufacturers downplay this issue. LG said in 2016 that its OLED televisions can endure 100,000 hours before they degrade to half their original maximum brightness. The company’s current OLED reliability page says that “reasonable, responsible usage” should not result in burn-in.
Want to see the effects yourself? I recommend Rting’s burn-in testing page, which shows results over a period of eight years (though, unfortunately, Rtings has not updated its result since February of 2020). This testing shows OLED degradation is indeed a thing, though its severity depends on how you use your display.
You might decide the risk is worth the reward. But if you want a display that you’ll use all day, day after day, for a decade or more, OLED isn’t the best choice. The burn-in is real.
Monitor pricing remains a sore point for PC enthusiasts. As explained in my deep-dive on upcoming OLED monitors, pricing is tied to the efficiency of production.
“OLEDs are less costly than MiniLEDs in tablets and notebooks if comparing them to Apple’s iPad Pro and MacBook Pro,” says Young. “On the other hand, in monitors, OLEDs are more expensive than MiniLEDs, and are not as bright.”
This explanation is backed up by the hardware you can buy today. OLED panels are available at reasonable prices in notebooks like the Dell XPS 13 and Samsung Galaxy Book Pro. OLED panels for monitors, on the other hand, are so expensive most manufacturers don’t even bother. The LG UltraFine 32EP950, which briefly went on sale this summer, retailed for $3,999.99.
Mini-LED is also expensive, but more affordable than OLED. Asus’ 32-inch ROG Swift PG32UQX retails for as little as $2,899.99 and Samsung’s super-ultrawide Odyssey Neo G9 is $2,499.99.
This advantage will likely continue in the near future. OLED pricing is reliant on availability of OLED panels, which are not as widely produced as LCD panels. Companies looking to build Mini-LED displays can design the backlight somewhat independently of the LCD panel and choose panels as needed based on the panel’s capabilities and pricing.
Because of this, there’s more ways for manufacturers to deliver Mini-LED displays in notebooks and monitors, which may lead to a more aggressive reduction in price.
The current OLED vs. Mini-LED battle is give-and-take. Mini-LED wins in brightness, HDR, durability, and pricing (of full-sized monitors). OLED wins in contrast, black levels, viewing angles, and motion performance.
OLED’s big break may come with the introduction of new fabs. Young says they will “lower costs significantly for 10-inch to 32-inch panels, giving OLED fabs the same flexibility as G8.5 LCD fabs, meaning the ability to target multiple applications from a single fab.” The first of these new fabs should start producing panels by 2024.
Affordable OLED seems alluring, but Wyatt champions a different approach. He believes the Micro-LED technology championed by Pixel Display will meld the strengths of LCD and OLED while ditching the weaknesses of both.
However, Micro-LED is a technology more relevant to the latter half of this decade. The more immediate fight will see OLED attempt to improve brightness and durability while Mini-LED pursues increasingly sophisticated backlights to mimic the contrast of OLED.
Personally, I think Mini-LED shows more promise—when it comes to PC displays, at least. The static images, long hours, and sustained brightness of Mini-LED displays pinches on OLED pain points, which will remain even if pricing becomes more affordable.
Shopping for a new TV is like wading through a never-ending pool of tech jargon, display terminology, and head-spinning acronyms. It was one thing when 4K resolution landed in the homes of consumers, with TV brands touting the new UHD viewing spec as a major marketing grab. But over the last several years, the plot has only continued to thicken when it comes to three- and four-letter acronyms with the introduction of state-of-the-art lighting and screen technology. But between OLEDs, QLEDs, mini-LEDs, and now QD-OLEDs, there’s one battle of words that rests at the core of TV vocabulary: LED versus LCD.
Despite having a different acronym, LED TV is just a specific type of LCD TV, which uses a liquid crystal display (LCD) panel to control where light is displayed on your screen. These panels are typically composed of two sheets of polarizing material with a liquid crystal solution between them. When an electric current passes through the liquid, it causes the crystals to align, so that light can (or can’t) pass through. Think of it as a shutter, either allowing light to pass through or blocking it out.
Since both LED and LCD TVs are based around LCD technology, the question remains: what is the difference? Actually, it’s about what the difference was. Older LCD TVs used cold cathode fluorescent lamps (CCFLs) to provide lighting, whereas LED LCD TVs used an array of smaller, more efficient light-emitting diodes (LEDs) to illuminate the screen.
Since the technology is better, all LCD TVs now use LED lights and are colloquially considered LED TVs. For those interested, we’ll go deeper into backlighting below, or you can move onto the Local Dimming section.
Three basic illumination forms have been used in LCD TVs: CCFL backlighting, full-array LED backlighting, and LED edge lighting. Each of these illumination technologies is different from one another in important ways. Let’s dig into each.
CCFL backlighting is an older, now-abandoned form of display technology in which a series of cold cathode lamps sit across the inside of the TV behind the LCD. The lights illuminate the crystals fairly evenly, which means all regions of the picture will have similar brightness levels. This affects some aspects of picture quality, which we discuss in more detail below. Since CCFLs are larger than LED arrays, CCFL-based LCD TVs are thicker than LED-backlit LCD TVs.
Full-array backlighting swaps the outdated CCFLs for an array of LEDs spanning the back of the screen, comprising zones of LEDs that can be lit or dimmed in a process called local dimming. TVs using full-array LED backlighting to make up a healthy chunk of the high-end LED TV market, and with good reason — with more precise and even illumination, they can create better picture quality than CCFL LCD TVs were ever able to achieve, with better energy efficiency to boot.
Another form of LCD screen illumination is LED edge lighting. As the name implies, edge-lit TVs have LEDs along the edges of a screen. There are a few different configurations, including LEDs along just the bottom, LEDs on the top and bottom, LEDs left and right, and LEDs along all four edges. These different configurations result in picture quality differences, but the overall brightness capabilities still exceed what CCFL LCD TVs could achieve. While there are some drawbacks to edge lighting compared to full-array or direct backlight displays, the upshot is edge lighting that allows manufacturers to make thinner TVs that cost less to manufacture.
To better close the local-dimming quality gap between edge-lit TVs and full-array back-lit TVs, manufacturers like Sony and Samsung developed their own advanced edge lighting forms. Sony’s technology is known as “Slim Backlight Master Drive,” while Samsung has “Infinite Array” employed in its line of QLED TVs. These keep the slim form factor achievable through edge-lit design and local dimming quality more on par with full-array backlighting.
Local dimming is a feature of LED LCD TVs wherein the LED light source behind the LCD is dimmed and illuminated to match what the picture demands. LCDs can’t completely prevent light from passing through, even during dark scenes, so dimming the light source itself aids in creating deeper blacks and more impressive contrast in the picture. This is accomplished by selectively dimming the LEDs when that particular part of the picture — or region — is intended to be dark.
Local dimming helps LED/LCD TVs more closely match the quality of modern OLED displays, which feature better contrast levels by their nature — something CCFL LCD TVs couldn’t do. The quality of local dimming varies depending on which type of backlighting your LCD uses, how many individual zones of backlighting are employed, and the quality of the processing. Here’s an overview of how effective local dimming is on each type of LCD TV.
TVs with full-array backlighting have the most accurate local dimming and therefore tend to offer the best contrast. Since an array of LEDs spans the entire back of the LCD screen, regions can generally be dimmed with more finesse than on edge-lit TVs, and brightness tends to be uniform across the entire screen. Hisense’s impressive U7G TVs are great examples of relatively affordable models that use multiple-zone, full-array backlighting with local dimming.
“Direct local dimming” is essentially the same thing as full-array dimming, just with fewer LEDs spread further apart in the array. However, it’s worth noting that many manufacturers do not differentiate “direct local dimming” from full-array dimming as two separate forms of local dimming. We still feel it’s important to note the difference, as fewer, further-spaced LEDs will not have the same accuracy and consistency as full-array displays.
Because edge lighting employs LEDs positioned on the edge or edges of the screen to project light across the back of the LCD screen, as opposed to coming from directly behind it, it can result in very subtle blocks or bands of lighter pixels within or around areas that should be dark. The local dimming of edge-lit TVs can sometimes result in some murkiness in dark areas compared with full-array LED TVs. It should also be noted that not all LED edge-lit TVs offer local dimming, which is why it is not uncommon to see glowing strips of light at the edges of a TV and less brightness toward the center of the screen.
Since CCFL backlit TVs do not use LEDs, models with this lighting style do not have dimming abilities. Instead, the LCD panel of CCFL LCDs is constantly and evenly illuminated, making a noticeable difference in picture quality compared to LED LCDs. This is especially noticeable in scenes with high contrast, as the dark portions of the picture may appear too bright or washed out. When watching in a well-lit room, it’s easier to ignore or miss the difference, but in a dark room, it will be, well, glaring.
As if it wasn’t already confusing enough, once you begin exploring the world of modern display technology, new acronyms crop up. The two you’ll most commonly find are OLED and QLED.
An OLED display uses a panel of pixel-sized organic compounds that respond to electricity. Since each tiny pixel (millions of which are present in modern displays) can be turned on or off individually, OLED displays are called “emissive” displays (meaning they require no backlight). They offer incredibly deep contrast ratios and better per-pixel accuracy than any other display type on the market.
Because they don’t require a separate light source, OLED displays are also amazingly thin — often just a few millimeters. OLED panels are often found on high-end TVs in place of LED/LCD technology, but that doesn’t mean that LED/LCDs aren’t without their own premium technology.
QLED is a premium tier of LED/LCD TVs from Samsung. Unlike OLED displays, QLED is not a so-called emissive display technology (lights still illuminate QLED pixels from behind). However, QLED TVs feature an updated illumination technology over regular LED LCDs in the form of Quantum Dot material (hence the “Q” in QLED), which raises overall efficiency and brightness. This translates to better, brighter grayscale and color and enhances HDR (High Dynamic Range) abilities.
And now to make things extra confusing, part of Samsung’s 2022 TV lineup is being billed as traditional OLEDs, although a deeper dive will reveal this is actually the company’s first foray into a new panel technology altogether called QD-OLED.
For a further description of QLED and its features, read our list of the best TVs you can buy. The article further compares the qualities of both QLED and OLED TV; however, we also recommend checking outfor a side-by-side look at these two top-notch technologies.
There are more even displays to become familiar with, too, including microLED and Mini-LED, which are lining up to be the latest head-to-head TV technologies. Consider checking out how the two features compare to current tech leaders in
In the world of TV technology, there’s never a dull moment. However, with this detailed research, we hope you feel empowered to make an informed shopping decision and keep your Best Buy salesperson on his or her toes.
There are plenty of new and confusing terms facing TV shoppers today, but when it comes down to the screen technology itself, there are only two: Nearly every TV sold today is either LCD or OLED.
The biggest between the two is in how they work. With OLED, each pixel provides its own illumination so there"s no separate backlight. With an LCD TV, all of the pixels are illuminated by an LED backlight. That difference leads to all kinds of picture quality effects, some of which favor LCD, but most of which benefit OLED.
LCDs are made by a number of companies across Asia. All current OLED TVs are built by LG Display, though companies like Sony and Vizio buy OLED panels from LG and then use their own electronics and aesthetic design.
So which one is better? Read on for their strengths and weaknesses. In general we"ll be comparing OLED to the best (read: most expensive) LCD has to offer, mainly because there"s no such thing as a cheap OLED TV (yet).
At the other side of light output is black level, or how dark the TV can get. OLED wins here because of its ability to turn off individual pixels completely. It can produce truly perfect black.
The better LCDs have local dimming, where parts of the screen can dim independently of others. This isn"t quite as good as per-pixel control because the black areas still aren"t absolutely black, but it"s better than nothing. The best LCDs have full-array local dimming, which provides even finer control over the contrast of what"s onscreen -- but even they can suffer from "blooming," where a bright area spoils the black of an adjacent dark area.
Here"s where it comes together. Contrast ratio is the difference between the brightest and the darkest a TV can be. OLED is the winner here because it can get extremely bright, plus it can produce absolute black with no blooming. It has the best contrast ratio of any modern display.
One of the main downsides of LCD TVs is a change in picture quality if you sit away from dead center (as in, off to the sides). How much this matters to you certainly depends on your seating arrangement, but also on how much you love your loved ones.
A few LCDs use in-plane switching (IPS) panels, which have better off-axis picture quality than other kinds of LCDs, but don"t look as good as other LCDs straight on (primarily due to a lower contrast ratio).
OLED doesn"t have the off-axis issue LCDs have; its image looks basically the same, even from extreme angles. So if you have a wide seating area, OLED is the better option.
Nearly all current TVs are HDR compatible, but that"s not the entire story. Just because a TV claims HDR compatibility doesn"t mean it can accurately display HDR content. All OLED TVs have the dynamic range to take advantage of HDR, but lower-priced LCDs, especially those without local-dimming backlights, do not. So if you want to see HDR content it all its dynamic, vibrant beauty, go for OLED or an LCD with local dimming.
In our tests comparing the best new OLED and LCD TVs with HDR games and movies, OLED usually looks better. Its superior contrast and lack of blooming win the day despite LCD"s brightness advantage. In other words LCD TVs can get brighter, especially in full-screen bright scenes and HDR highlights, but none of them can control that illumination as precisely as an OLED TV.
OLED"s energy consumption is directly related to screen brightness. The brighter the screen, the more power it draws. It even varies with content. A dark movie will require less power than a hockey game or ski competition.
The energy consumption of LCD varies depending on the backlight setting. The lower the backlight, the lower the power consumption. A basic LED LCD with its backlight set low will draw less power than OLED.
LG has said their OLED TVs have a lifespan of 100,000 hours to half brightness, a figure that"s similar to LED LCDs. Generally speaking, all modern TVs are quite reliable.
Does that mean your new LCD or OLED will last for several decades like your parent"s last CRT (like the one pictured). Probably not, but then, why would you want it to? A 42-inch flat panel cost $14,000 in the late 90"s, and now a 65-inch TV with more than 16x the resolution and a million times better contrast ratio costs $1,400. Which is to say, by the time you"ll want/need to replace it, there will be something even better than what"s available now, for less money.
OLED TVs are available in sizes from 48 to 88 inches, but LCD TVs come in smaller and larger sizes than that -- with many more choices in between -- so LCD wins. At the high end of the size scale, however, the biggest "TVs" don"t use either technology.
If you want something even brighter, and don"t mind spending a literal fortune to get it, Samsung, Sony, and LG all sell direct-view LED displays. In most cases these are
You can get 4K resolution, 50-inch LCDs for around $400 -- or half that on sale. It"s going to be a long time before OLEDs are that price, but they have come down considerably.
LCD dominates the market because it"s cheap to manufacture and delivers good enough picture quality for just about everybody. But according to reviews at CNET and elsewhere, OLED wins for overall picture quality, largely due to the incredible contrast ratio. The price difference isn"t as severe as it used to be, and in the mid- to high-end of the market, there are lots of options.
IPS (In-Plane Switching) lcd is still a type of TFT LCD, IPS TFT is also called SFT LCD (supper fine tft ),different to regular tft in TN (Twisted Nematic) mode, theIPS LCD liquid crystal elements inside the tft lcd cell, they are arrayed in plane inside the lcd cell when power off, so the light can not transmit it via theIPS lcdwhen power off, When power on, the liquid crystal elements inside the IPS tft would switch in a small angle, then the light would go through the IPS lcd display, then the display on since light go through the IPS display, the switching angle is related to the input power, the switch angle is related to the input power value of IPS LCD, the more switch angle, the more light would transmit the IPS LCD, we call it negative display mode.
The regular tft lcd, it is a-si TN (Twisted Nematic) tft lcd, its liquid crystal elements are arrayed in vertical type, the light could transmit the regularTFT LCDwhen power off. When power on, the liquid crystal twist in some angle, then it block the light transmit the tft lcd, then make the display elements display on by this way, the liquid crystal twist angle is also related to the input power, the more twist angle, the more light would be blocked by the tft lcd, it is tft lcd working mode.
A TFT lcd display is vivid and colorful than a common monochrome lcd display. TFT refreshes more quickly response than a monochrome LCD display and shows motion more smoothly. TFT displays use more electricity in driving than monochrome LCD screens, so they not only cost more in the first place, but they are also more expensive to drive tft lcd screen.The two most common types of TFT LCDs are IPS and TN displays.
TFT LCD is a mature technology. OLED is a relatively new display technology, being used in more and more applications. As for Micro LED, it is a new generation technology with very promising future. Followings are the pros and cons of each display technology.
TFT Liquid Crystal Display is widely used these days. Since LCD itself doesn"t emit light. TFT LCD relies on white LED backlight to show content. This is an explanation of how TFT LCD works.
Relatively lower contrast:Light needs to pass through LCD glasses, liquid crystal layer, polarizers and color filters. Over 90% is lost. Also, LCD can not display pure black.
Organic Light-Emitting Diode is built from an electro-luminescent layer that contains organic compounds, which emit light in response to an electric current. There are two types of OLED, Passive Matrix OLED (PMOLED) and Active Matrix OLED (AMOLED). These driving methods are similar to LCD"s. PMOLED is controlled sequentially using a matrix addressing scheme, m + n control signals are required to address a m x n display. AMOLED uses a TFT backplane that can switch individual pixels on and off.
Low power consumption and flexible: OLED doesn"t rely on backlight and consumes less power. OLED is essentially created on plastic film. It is bendable and easy to process.
High contrast and vivid color: OLED emits light itself, can produce very bright image with beautiful color. And because OLED can be turned off, it can produce true black.
Stroboscopic effect: most OLED screen uses PWM dimming technology. Some people who are easy perceive stroboscopic frequency may have sore eyes and tears.
Micro LED, sometimes called μLED is made up of tiny LED, measure less than 100μm. Another way of looking at this is that MicroLEDs are simply traditional LEDs shrunk down and placed into an array.
Replacing organic material with inorganic GaN material eliminates the need of polarizing and encapsulation layer, found in OLED. Micro LED is smaller and thinner, consumes less power.
In recent years, China and other countries have invested heavily in the research and manufacturing capacity of display technology. Meanwhile, different display technology scenarios, ranging from traditional LCD (liquid crystal display) to rapidly expanding OLED (organic light-emitting diode) and emerging QLED (quantum-dot light-emitting diode), are competing for market dominance. Amidst the trivium strife, OLED, backed by technology leader Apple"s decision to use OLED for its iPhone X, seems to have a better position, yet QLED, despite still having technological obstacles to overcome, has displayed potential advantage in color quality, lower production costs and longer life.
Zhao: We all know display technologies are very important. Currently, there are OLED, QLED and traditional LCD technologies competing with each other. What are their differences and specific advantages? Shall we start from OLED?
Huang: OLED has developed very quickly in recent years. It is better to compare it with traditional LCD if we want to have a clear understanding of its characteristics. In terms of structure, LCD largely consists of three parts: backlight, TFT backplane and cell, or liquid section for display. Different from LCD, OLED lights directly with electricity. Thus, it does not need backlight, but it still needs the TFT backplane to control where to light. Because it is free from backlight, OLED has a thinner body, higher response time, higher color contrast and lower power consumption. Potentially, it may even have a cost advantage over LCD. The biggest breakthrough is its flexible display, which seems very hard to achieve for LCD.
Liao: Actually, there were/are many different types of display technologies, such as CRT (cathode ray tube), PDP (plasma display panel), LCD, LCOS (liquid crystals on silicon), laser display, LED (light-emitting diodes), SED (surface-conduction electron-emitter display), FED (filed emission display), OLED, QLED and Micro LED. From display technology lifespan point of view, Micro LED and QLED may be considered as in the introduction phase, OLED is in the growth phase, LCD for both computer and TV is in the maturity phase, but LCD for cellphone is in the decline phase, PDP and CRT are in the elimination phase. Now, LCD products are still dominating the display market while OLED is penetrating the market. As just mentioned by Dr Huang, OLED indeed has some advantages over LCD.
Huang: Despite the apparent technological advantages of OLED over LCD, it is not straightforward for OLED to replace LCD. For example, although both OLED and LCD use the TFT backplane, the OLED’s TFT is much more difficult to be made than that of the voltage-driven LCD because OLED is current-driven. Generally speaking, problems for mass production of display technology can be divided into three categories, namely scientific problems, engineering problems and production problems. The ways and cycles to solve these three kinds of problems are different.
At present, LCD has been relatively mature, while OLED is still in the early stage of industrial explosion. For OLED, there are still many urgent problems to be solved, especially production problems that need to be solved step by step in the process of mass production line. In addition, the capital threshold for both LCD and OLED are very high. Compared with the early development of LCD many years ago, the advancing pace of OLED has been quicker.While in the short term, OLED can hardly compete with LCD in large size screen, how about that people may change their use habit to give up large screen?
Liao: I want to supplement some data. According to the consulting firm HIS Markit, in 2018, the global market value for OLED products will be US$38.5 billion. But in 2020, it will reach US$67 billion, with an average compound annual growth rate of 46%. Another prediction estimates that OLED accounts for 33% of the display market sales, with the remaining 67% by LCD in 2018. But OLED’s market share could reach to 54% in 2020.
Huang: While different sources may have different prediction, the advantage of OLED over LCD in small and medium-sized display screen is clear. In small-sized screen, such as smart watch and smart phone, the penetration rate of OLED is roughly 20% to 30%, which represents certain competitiveness. For large size screen, such as TV, the advancement of OLED [against LCD] may need more time.
Xu: LCD was first proposed in 1968. During its development process, the technology has gradually overcome its own shortcomings and defeated other technologies. What are its remaining flaws? It is widely recognized that LCD is very hard to be made flexible. In addition, LCD does not emit light, so a back light is needed. The trend for display technologies is of course towards lighter and thinner (screen).
But currently, LCD is very mature and economic. It far surpasses OLED, and its picture quality and display contrast do not lag behind. Currently, LCD technology"s main target is head-mounted display (HMD), which means we must work on display resolution. In addition, OLED currently is only appropriate for medium and small-sized screens, but large screen has to rely on LCD. This is why the industry remains investing in the 10.5th generation production line (of LCD).
Xu: While deeply impacted by OLED’s super thin and flexible display, we also need to analyse the insufficiency of OLED. With lighting material being organic, its display life might be shorter. LCD can easily be used for 100 000 hours. The other defense effort by LCD is to develop flexible screen to counterattack the flexible display of OLED. But it is true that big worries exist in LCD industry.
LCD industry can also try other (counterattacking) strategies. We are advantageous in large-sized screen, but how about six or seven years later? While in the short term, OLED can hardly compete with LCD in large size screen, how about that people may change their use habit to give up large screen? People may not watch TV and only takes portable screens.
Some experts working at a market survey institute CCID (China Center for Information Industry Development) predicted that in five to six years, OLED will be very influential in small and medium-sized screen. Similarly, a top executive of BOE Technology said that after five to six years, OLED will counterweigh or even surpass LCD in smaller sizes, but to catch up with LCD, it may need 10 to 15 years.
Xu: Besides LCD, Micro LED (Micro Light-Emitting Diode Display) has evolved for many years, though people"s real attention to the display option was not aroused until May 2014 when Apple acquired US-based Micro LED developer LuxVue Technology. It is expected that Micro LED will be used on wearable digital devices to improve battery"s life and screen brightness.
Micro LED, also called mLED or μLED, is a new display technology. Using a so-called mass transfer technology, Micro LED displays consist of arrays of microscopic LEDs forming the individual pixel elements. It can offer better contrast, response times, very high resolution and energy efficiency. Compared with OLED, it has higher lightening efficiency and longer life span, but its flexible display is inferior to OLED. Compared with LCD, Micro LED has better contrast, response times and energy efficiency. It is widely considered appropriate for wearables, AR/VR, auto display and mini-projector.
However, Micro LED still has some technological bottlenecks in epitaxy, mass transfer, driving circuit, full colorization, and monitoring and repairing. It also has a very high manufacturing cost. In short term, it cannot compete traditional LCD. But as a new generation of display technology after LCD and OLED, Micro LED has received wide attentions and it should enjoy fast commercialization in the coming three to five years.
Peng: It comes to quantum dot. First, QLED TV on market today is a misleading concept. Quantum dots are a class of semiconductor nanocrystals, whose emission wavelength can be continuously tuned because of the so-called quantum confinement effect. Because they are inorganic crystals, quantum dots in display devices are very stable. Also, due to their single crystalline nature, emission color of quantum dots can be extremely pure, which dictates the color quality of display devices.
Interestingly, quantum dots as light-emitting materials are related to both OLED and LCD. The so-called QLED TVs on market are actually quantum-dot enhanced LCD TVs, which use quantum dots to replace the green and red phosphors in LCD’s backlight unit. By doing so, LCD displays greatly improve their color purity, picture quality and potentially energy consumption. The working mechanisms of quantum dots in these enhanced LCD displays is their photoluminescence.
For its relationship with OLED, quantum-dot light-emitting diode (QLED) can in certain sense be considered as electroluminescence devices by replacing the organic light-emitting materials in OLED. Though QLED and OLED have nearly identical structure, they also have noticeable differences. Similar to LCD with quantum-dot backlighting unit, color gamut of QLED is much wider than that of OLED and it is more stable than OLED.
Another big difference between OLED and QLED is their production technology. OLED relies on a high-precision technique called vacuum evaporation with high-resolution mask. QLED cannot be produced in this way because quantum dots as inorganic nanocrystals are very difficult to be vaporized. If QLED is commercially produced, it has to be printed and processed with solution-based technology. You can consider this as a weakness, since the printing electronics at present is far less precision than the vacuum-based technology. However, solution-based processing can also be considered as an advantage, because if the production problem is overcome, it costs much less than the vacuum-based technology applied for OLED. Without considering TFT, investment into an OLED production line often costs tens of billions of yuan but investment for QLED could be just 90–95% less.
Given the relatively low resolution of printing technology, QLED shall be difficult to reach a resolution greater than 300 PPI (pixels per inch) within a few years. Thus, QLED might not be applied for small-sized displays at present and its potential will be medium to large-sized displays.
Peng: Good questions. Ligand chemistry of quantum dots has developed quickly in the past two to three years. Colloidal stability of inorganic nanocrystals should be said of being solved. We reported in 2016 that one gram of quantum dots can be stably dispersed in one milliliter of organic solution, which is certainly sufficient for printing technology. For the second question, several companies have been able to mass produce quantum dots. At present, all these production volume is built for fabrication of the backlighting units for LCD. It is believed that all high-end TVs from Samsung in 2017 are all LCD TVs with quantum-dot backlighting units. In addition, Nanosys in the United States is also producing quantum dots for LCD TVs. NajingTech at Hangzhou, China demonstrate production capacity to support the Chinese TV makers. To my knowledge, NajingTech is establishing a production line for 10 million sets of color TVs with quantum-dot backlighting units annually.China"s current demands cannot be fully satisfied from the foreign companies. It is also necessary to fulfill the demands of domestic market. That is why China must develop its OLED production capability.
Huang: Based on my understanding of Samsung, the leading Korean player in OLED market, we cannot say it had foresight in the very beginning. Samsung began to invest in AMOLED (active-matrix organic light-emitting diode, a major type of OLED used in the display industry) in about 2003, and did not realize mass production until 2007. Its OLED production reached profitability in 2010. Since then, Samsung gradually secured a market monopoly status.
So, originally, OLED was only one of Samsung"s several alternative technology pathways. But step by step, it achieved an advantageous status in the market and so tended to maintain it by expanding its production capacity.
Another reason is customers’ demands. Apple has refrained itself from using OLED for some years due to various reasons, including the patent disputes with Samsung. But after Apple began to use OLED for its iPhone X, it exerted a big influence in the whole industry. So now Samsung began to harvest its accumulated investments in the field and began to expand the capacity more.
Liao: South Korean manufacturers including Samsung and LG Electronics have controlled 90% of global supplies of medium and small-sized OLED panels. Since Apple began to buy OLED panels from Samsung for its cellphone products, there were no more enough panels shipping to China. Therefore, China"s current demands cannot be fully satisfied from the foreign companies. On the other hand, because China has a huge market for cellphones, it would be necessary to fulfill the demands through domestic efforts. That is why China must develop its OLED production capability.
Huang: The importance of China"s LCD manufacturing is now globally high. Compared with the early stage of LCD development, China"s status in OLED has been dramatically improved. When developing LCD, China has adopted the pattern of introduction-absorption-renovation. Now for OLED, we have a much higher percentage of independent innovation.
Then it is the scale of human resources. One big factory will create several thousand jobs, and it will mobilize a whole production chain, involving thousands of workers. The requirement of supplying these engineers and skilled workers can be fulfilled in China.
The third advantage is the national supports. The government has input huge supports and manufacturers’ technological capacity is improving. I think Chinese manufacturers will have a great breakthrough in OLED.
Although we cannot say that our advantages triumph over ROK, where Samsung and LG have been dominating the field for many years, we have achieved many significant progresses in developing the material and parts of OLED. We also have high level of innovation in process technology and designs. We already have several major manufacturers, such as Visionox, BOE, EDO and Tianma, which have owned significant technological reserves.
Peng: As mentioned above, there are two ways to apply quantum dots for display, namely photoluminescence in backlightingFor QLED, the three stages of technological development [from science issue to engineering and finally to mass production] have been mingled together at the same time. If one wants to win the competition, it is necessary to invest on all three dimensions.
units for LCD and electroluminescence in QLED. For the photoluminescence applications, the key is quantum-dot materials. China has noticeable advantages in quantum-dot materials.
China is internationally leading in electroluminescence at present. In fact, it was the 2014 Nature publication by a group of scientists from Zhejiang University that proved QLED can reach the stringent requirements for display applications. However, who will become the final winner of the international competition on electroluminescence remains unclear. China"s investment in quantum-dot technology lags far behind US and ROK. Basically, the quantum-dot research has been centered in US for most of its history, and South Korean players have invested heavily along this direction as well.
For electroluminescence, it is very likely to co-exist with OLED for a long period of time. This is so because, in small screen, QLED’s resolution is limited by printing technology.
Peng: If electroluminescence can be successfully achieved with printing, it will be much cheaper, with only about 1/10th cost of OLED. Manufacturers like NajingTech and BOE in China have demonstrated printing displays with quantum dots. At present, QLED does not compete with OLED directly, given its market in small-sized screen. A while ago, Dr. Huang mentioned three stages of technological development, from science issue to engineering and finally to mass production. For QLED, the three stages have been mingled together at the same time. If one wants to win the competition, it is necessary to invest on all three dimensions.
Huang: When OLED was compared with LCD in the past, lots of advantages of OLED were highlighted, such as high color gamut, high contrast and high response speed and so on. But above advantages would be difficult to be the overwhelming superiority to make the consumers to choose replacement.
It seems to be possible that the flexible display will eventually lead a killer advantage. I think QLED will also face similar situation. What is its real advantage if it is compared with OLED or LCD? For QLED, it seems to have been difficult to find the advantage in small screen. Dr. Peng has suggested its advantage lies in medium-sized screen, but what is its uniqueness?
Peng: The two types of key advantages of QLED are discussed above. One, QLED is based on solution-based printing technology, which is low cost and high yield. Two, quantum-dot emitters vender QLED with a large color gamut, high picture quality and superior device lifetime. Medium-sized screen is easiest for the coming QLED technologies but QLED for large screen is probably a reasonable extension afterwards.
Huang: But customers may not accept only better wider color range if they need to pay more money for this. I would suggest QLED consider the changes in color standards, such as the newly released BT2020 (defining high-definition 4 K TV), and new unique applications which cannot be satisfied by other technologies. The future of QLED seems also relying on the maturity of printing technology.
Peng: New standard (BT2020) certainly helps QLED, given BT2020 meaning a broad color gamut. Among the technologies discussed today, quantum-dot displays in either form are the only ones that can satisfy BT2020 without any optical compensation. In addition, studies found that the picture quality of display is highly associated with color gamut. It is correct that the maturity of printing technology plays an important role in the development of QLED. The current printing technology is ready for medium-sized screen and should be able to be extended to large-sized screen without much trouble.
Xu: For QLED to become a dominant technology, it is still difficult. In its development process, OLED precedes it and there are other rivaling technologies following. While we know owning the foundational patents and core technologies of QLED can make you a good position, holding core technologies alone cannot ensure you to become a mainstream technology. The government"s investment in such key technologies after all is small as compared with industry and cannot decide QLED to become mainstream technology.
Peng: Domestic industry sector has begun to invest in these future technologies. For example, NajingTech has invested about 400 million yuan ($65 million) in QLED, primarily in electroluminescence. There are some leading domestic players having invested into the field. Yes, this is far from enough. For example, there are few domestic companies investing R&D of printing technologies. Our printing equipment is primarily made by the US, European and Japan players. I think this is also a chance for China (to develop the printing technologies).
Liao: Due to their lack of kernel technologies, Chinese OLED panel manufacturers heavily rely on investments to improve their market competitiveness. But this may cause the overheated investment in the OLED industry. In recent years, China has already imported quite a few new OLED production lines with the total cost of about 450 billion yuan (US$71.5 billion).Lots of advantages of OLED over LCD were highlighted, such as high color gamut, high contrast and high response speed and so on …. It seems to be possible that the flexible display will eventually lead a killer advantage.
The short of talent human resources perhaps is another issue to influence the fast expansion of the industry domestically. For an example, BOE alone demands more than 1000 new engineers last year. However, the domestic universities certainly cannot fulfill this requirement for specially trained OLED working forces currently. A major problem is the training is not implemented in accordance with industry demands but surrounding academic papers.
Liao: However, Chinese researchers’ priority pursuit of papers is in disjunction from industry demand. Majority of people (at universities) who are working on organic optoelectronics are more interested in the fields of QLED, organic solar cells, perovskite solar cells and thin-film transistors because they are trendy fields and have more chances to publish research papers. On the other hand, many studies that are essential to solve industry"s problems, such as developing domestic versions of equipment, are not so essential for paper publication, so that faculty and students shed from them.
Zhao: Today there are really good observations, discussions and suggestions. The industry-academics-research collaboration is crucial to the future of China"s display technologies. We all should work hard on this.
KLA is proud to be part of the most significant technological breakthroughs that help create the devices and ideas that transform our current life and shape our future. One of the latest emerging trends is a renewed focus on microLED technology.
As the name suggests, a microLED, or µLED, is a light-emitting diode (LED) – roughly 100 times smaller than conventional LEDs. MicroLEDs can be arranged into arrays to make high-resolution displays for applications ranging from smartwatches to very large displays – unlike conventional LEDs, which are suitable only for very large displays like billboards or stadium screens.
MicroLED technology was invented in 2000. However, it wasn"t until 2012 that a major consumer electronics company demonstrated a 55-inch, high-definition microLED TV. Other companies followed with their own demonstrations in 2018 and 2019 at retail prices of $80,000 for 89-inch models, making the technology out of reach for most consumers. Although microLED can potentially offer significant advantages over LCD or organic light-emitting diode (OLED) screens, technology issues and production costs have prevented widespread commercialization.
KLA – which has supported the global display industry for more than 40 years – has during the past decade been helping leaders in microLED technologies to overcome many of the obstacles to mass production and reduced costs.
"Our proven process and process control products are designed to meet the unique and demanding challenges of the complex microLED production flow to help accelerate wide market adoption," said Chet Lenox, KLA fellow, industry and customer collaboration.
While more products, based on slightly larger "miniLEDs" (typically ~50µm-300µm square), have been brought to market successfully in recent years as a way to improve on traditional LED backlighting for LCD displays, screen manufacturers and their supply chain are still committed to developing the more advanced microLED technology. In addition to the key goal of reducing product cost for consumers, companies are investing heavily in microLEDs for use in small products like watches and augmented reality (AR) headsets because they deliver better energy efficiency, consistent pixel quality and other key benefits as shown in the graphics below.
The potential market is huge. Shipping for microLED displays is expected to total 5 million and generate $7 billion in revenue by 2025, rising to more than 11 million units shipped in 2027, according to global technology research firm Omdia.
A key factor behind the industry"s focus on microLEDs is that LCD and OLED displays are produced on large substrates, where all layers are deposited one after the other. The larger the substrate, the more efficient the process – but large single displays can be difficult to handle and ship. MicroLEDs displays, however, can be produced using seamless tiling of small modules into larger displays.
The schematic cross-section of a typical microLED display (below) shows the simpler and thinner structure of a microLED compared to a thin film transistor liquid crystal display (TFT LCD) or OLED display, with the red/green/blue LED chips and a single electrode encased between the substrate and glass cover. The precise arrangement of the red, green and blue sub-pixels will vary among models and may even be stacked on top of each other.
MicroLEDs offer viewing performance equivalent to or, for some criteria such as brightness and refresh rate, better than OLED and LCD technologies. They also offer a longer life than OLED, thinner packaging and generally better energy efficiencies.
*Mass transferring millions of micro-sized red, green and blue microLEDs in the desired arrangement and precise locations (Solutions to avoid this might include the use of white or blue microLEDs with color conversion, growing uLEDs directly on silicon backplanes or using wafer-bonding of epi layers on the backplane.)
Each of the above would seem to add cost and make LCDs and OLEDs more economical. However, KLA"s metrology, inspection, wafer processing and repair solutions are critical to helping microLED manufacturers address these challenges, optimize yields, reduce the need for built-in redundancy and reduce expenditures to help microLED displays become a viable alternative to the established technologies.
KLA"s comprehensive portfolio of solutions for microLED manufacturing provides a pathway to yield improvement throughout the entire process – from epitaxy wafer to final display. KLA"s proven process and process control products are designed to meet the unique and demanding challenges of complex microLED production.
This rise of small, powerful components has also led to significant developments in display technology. The most recent of which, AMOLED, is now the main competitor for the most common display used in quality portable electronics – the TFT–LCD IPS (In-Plane Switching) display. As more factories in the Far East begin to produce AMOLED technology, it seems likely we will enter a battle of TFT IPS versus AMOLED, or LCD vs LED. Where a large percentage of a product’s cost is the display technology it uses, which provides best value for money when you’re designing a new product?
TFT IPSdisplays improved on previous TFT LCD technology, developed to overcome limitations and improve contrast, viewing angles, sunlight readability and response times. Viewing angles were originally very limited – so in-plane switching panels were introduced to improve them.
Modern TFT screens can have custom backlights turned up to whatever brightness that their power limit allows, which means they have no maximum brightness limitation. TFT IPS panels also have the option for OCA bonding, which uses a special adhesive to bond a touchscreen or glass coverlens to the TFT. This improves sunlight readability by preventing light from bouncing around between the layers of the display, and also improves durability without adding excess bulk; some TFT IPS displays now only measure around 2 mm thick.
AMOLED technology is an upgrade to older OLED technology. It uses organic compounds that emit light when exposed to electricity. This means no backlight, which in turn means less power consumption and a reduction in size. AMOLED screens tend to be thinner than TFT equivalents, often produced to be as thin as 1 mm. AMOLED technology also offers greater viewing angles thanks to deeper blacks. Colours tend to be greater, but visibility in daylight is lower than IPS displays.
As manufacturers increasingly focus on smaller devices, such as portable smartphones and wearable technology, the thinness and high colour resolution of AMOLED screens have grown desirable. However, producing AMOLED displays is far more costly as fewer factories offer the technology at a consistent quality and minimum order quantities are high; what capacity there is is often taken up the mobile phone market Full HD TFT IPS displays have the advantage of being offered in industry standard sizes and at a far lower cost, as well as offering superior sunlight visibility.
The competition between displays has benefitted both technologies as it has resulted in improvements in both. For example, Super AMOLED, a marketing brand by Samsung, involves the integration of a touchscreen layer inside the screen, rather than overlaid on it. The backlight in TFT technology means they can never truly replicate the deep blacks in AMOLED, but improvements have been made in resolution to the point where manufacturers like Apple have been happy to use LCD screens in their smartphones, even as they compete with Samsung’s Super AMOLED.
Aside from smartphones, many technologies utilise displays to offer direct interaction with customers. To decide whether TFT LCD will survive the rise of AMOLED technology, we must first recap the advantages of LCD. The backlit quality means that whites are bright and contrast is good, but this will wear down a battery faster than AMOLED. Additionally, cost is a significant factor for LCD screens. They are cheaper, more freely available and are offered in industry standard sizes so can be ordered for new products without difficulty.
It seems hard to deny that AMOLED will someday become the standard for mobile phones, which demand great colour performance and are reliant on battery life. Where size is an issue, AMOLED will also grow to dominance thanks to its superior thinness. But for all other technologies, particularly in industrial applications, TFT-LCD offers bright, affordable display technology that is continually improving as the challenge from AMOLED rises.
In one corner is LED (light-emitting diode). It’s the most common type of display on the market, however, it might be unfamiliar because there’s slight labelling confusion with LCD (liquid crystal display).
For display purposes the two are the same, and if you see a TV or smartphone that states it has an ‘LED’ screen, it’s an LCD. The LED part just refers to the lighting source, not the display itself.
In a nutshell, LED LCD screens use a backlight to illuminate their pixels, while OLED’s pixels produce their own light. You might hear OLED’s pixels called ‘self-emissive’, while LCD tech is ‘transmissive’.
The light of an OLED display can be controlled on a pixel-by-pixel basis. This sort of dexterity isn’t possible with an LED LCD – but there are drawbacks to this approach, which we’ll come to later.
In cheaper TVs and LCD-screen phones, LED LCD displays tend to use ‘edge lighting’, where LEDs sit to the side of the display, not behind it. The light from these LEDs is fired through a matrix that feeds it through the red, green and blue pixels and into our eyes.
LED LCD screens can go brighter than OLED. That’s a big deal in the TV world, but even more so for smartphones, which are often used outdoors and in bright sunlight.
Take an LCD screen into a darkened room and you may notice that parts of a purely black image aren’t black, because you can still see the backlighting (or edge lighting) showing through.
You’ll often see a contrast ratio quoted in a product’s specification, particularly when it comes to TVs and monitors. This tells you how much brighter a display’s whites are compared to its blacks. A decent LCD screen might have a contrast ratio of 1,000:1, which means the whites are a thousand times brighter than the blacks.
Contrast on an OLED display is far higher. When an OLED screen goes black, its pixels produce no light whatsoever. That means an infinite contrast ratio, although how great it looks will depend on how bright the screen can go. In general, OLED screens are best suited for use in darker rooms, and this is certainly the case where TVs are concerned.
OLED panels enjoy excellent viewing angles, primarily because the technology is so thin, and the pixels are so close to the surface. You can walk around an OLED TV or spread out in different spots in your living room, and you won’t lose out on contrast. For phones, viewing angles are extra important because you don’t tend to hold your hand perfectly parallel to your face.
Viewing angles are generally worse in LCDs, but this varies hugely depending on the display technology used. And there are lots of different kinds of LCD panel.
Perhaps the most basic is twisted nematic (TN). This is the type used in budget computer monitors, cheaper laptops, and very low-cost phones, and it offers poor angled viewing. If you’ve ever noticed that your computer screen looks all shadowy from a certain angle, it’s more than likely it uses a twisted nematic panel.
Thankfully, a lot of LCD devices use IPS panels these days. This stands for ‘in-plane switching’ and it generally provides better colour performance and dramatically improved viewing angles.
IPS is used in most smartphones and tablets, plenty of computer monitors and lots of TVs. It’s important to note that IPS and LED LCD aren’t mutually exclusive; it’s just another bit of jargon to tack on. Beware of the marketing blurb and head straight to the spec sheet.
The latest LCD screens can produce fantastic natural-looking colours. However, as is the case with viewing angles, it depends on the specific technology used.
OLED’s colours have fewer issues with pop and vibrancy, but early OLED TVs and phones had problems reining in colours and keeping them realistic. These days, the situation is better, Panasonic’s flagship OLEDs are used in the grading of Hollywood films.
Where OLED struggles is in colour volume. That is, bright scenes may challenge an OLED panel’s ability to maintain levels of colour saturation. It’s a weakness that LCD-favouring manufacturers enjoy pointing out.
Both have been the subject of further advancements in recent years. For LCD there’s Quantum Dot and Mini LED. The former uses a quantum-dot screen with blue LEDs rather than white LEDs and ‘nanocrystals’ of various sizes to convert light into different colours by altering its wavelength. Several TV manufacturers have jumped onboard Quantum Dot technology, but the most popular has been Samsung’s QLED branded TVs.
Mini LED is another derivation of LED LCD panels, employing smaller-sized LEDs that can emit more light than standard versions, increasing brightness output of the TV. And as they are smaller, more can be fitted into a screen, leading to greater control over brightness and contrast. This type of TV is becoming more popular, though in the UK and Europe it’s still relatively expensive. You can read more about Mini LED and its advantages in our explainer.
OLED, meanwhile, hasn’t stood still either. LG is the biggest manufacturer of large-sized OLED panels and has produced panels branded as evo OLED that are brighter than older versions. It uses a different material for its blue OLED material layer within the panel (deuterium), which can last for longer and can have more electrical current passed through it, increasing the brightness of the screen, and elevating the colour volume (range of colours it can display).
Another development is the eagerly anticipated QD-OLED. This display technology merges Quantum Dot backlights with an OLED panel, increasing the brightness, colour accuracy and volume, while retaining OLED’s perfect blacks, infinite contrast and potentially even wider viewing angles, so viewers can spread out anywhere in a room and see pretty much the same image. Samsung and Sonyare the two companies launching QD-OLED TVs in 2022.
And for smartphones there’s been a move towards AMOLED (Active-Matrix Organic Light Emitting Diode) screens for Android screens, while Apple has moved towards OLED for its smartphones and tried Mini LED with its iPad Pro. Technologies are consistently evolving with Superand Dynamic AMOLED versions available, more performance is being eked out.
While LED LCD has been around for much longer and is cheaper to make, manufacturers are beginning to move away from it, at least in the sense of the ‘standard’ LCD LED displays, opting to explore the likes of Mini LED and Quantum Dot var