It's hard to believe that the technology we use every day to view life-like images on our screens was developed more than 50 years ago. I’m referring, of course, to liquid crystal display, or LCD, technology. And while other innovations of the time, like VCRs and floppy disks, have since been relegated to the archives of history, LCD remains a dominant technology today without equal in price and mainstream adoption. But as expected, the industry is always looking ahead for the next big thing – including several emerging display technologies that Corning is prepared to support.
by Lori Hamilton, Director of Commercial Technology & Display Innovations, Corning
by Lori Hamilton, Director of Commercial Technology & Display Innovations, Corning
LCD Technology is Here to Stay
LCD remains the leading display technology by far, and we forecast that will it remain so for the foreseeable future. That’s largely because panel makers have worked to evolve the technology over the years, achieving performance that continues to beat expectations. This includes increasing size well past what was thought to be the 40-inch size barrier, enabling very thin and narrow bezels, and making displays as thin as today’s smartphones.
LCD technology is based on a backlight projecting light through a liquid crystal layer that’s sandwiched between two pieces of glass. When voltage is applied to this liquid crystal layer, it lets the light of an individual pixel pass through like a shutter. LCD is considered a transmissive display technology, as the light is transmitted through the display panel.
Corning's primary product offering for LCD technology is Corning® EAGLE XG® Slim Glass, which is the most widely adopted glass substrate in the display industry. In 2019, we celebrated an important milestone of manufacturing more than 25 billion square feet of this material for panel makers around the world, and we continue to see very strong demand for this glass composition today.
While LCD has undergone incredible innovations for half a century, we have also kept a close eye on competing technologies, such as OLED.
A Status Update on OLED
In OLED, or organic light emitting diode, displays, the picture is generated at a pixel level. An electrical current stimulates layers of organic material to emit light. Therefore, OLED displays are considered emissive displays as the display panel generates and emits light.
Today, OLED displays represent roughly one-third of the viewing area in small screen devices – like mobile phones and tablets, for example. We placed our bets on small-screen OLED more than five years ago when we launched Lotus™ NXT Glass, our highest-advantaged glass designed to withstand high temperature and demanding processing requirements. Today, we see strong customer demand for that glass, and we’re well positioned as phones continue to evolve from LCD to OLED displays with thinner, flexible form factors.
While we expect the overall impact of this transition to be minimal on the display glass market in the near-term, we're prepared to grow with the end market. In 2019, we launched Corning® Astra™ Glass as an excellent solution for mid-to-high range processing temperatures, such as those used to create some OLED displays. Astra is particularly well-suited for high-resolution applications like tablets and monitors, as well as 8K TVs.
OLED accounted for less than two percent of TV sell-through units in 2020. While we expect both LCD and OLED to continue to improve in terms of performance and cost, we expect that LCD will continue to dominate for large-area displays.
Display Technologies on the Cutting Edge
Besides the incumbents, LCD and OLED, the display industry has recently been peppered with new, and sometimes confusing, terms such as quantum dot (QD), mini- and microLED. Some of these are entirely new technologies and some of these are enhancements to existing technologies.
Take, miniLED, which provides a way to improve the picture quality of traditional backlit LCD and better compete with the impressive contrast ratio of OLED displays. The way it works is an array of extremely small LEDs – usually less than 0.3mm in diameter – make up the display’s backlight. This enables much more localized dimming zones, which results in blacker blacks and brighter whites on screen. MiniLED backlights can be considered an enhancement to LCD and are quickly becoming the latest trend in premium applications.
There are several opportunities for precision glass in these types of displays. The thermal and dimensional stability of glass, as well as the highly engineered optical characteristics enable the efficient management of light as well as extreme narrow bezel. For example, our diffuser glass was recently extended to Samsung’s flagship zero bezel 8K QLED TVs with miniLED backlights. This is a third piece of Corning glass in an LCD TV, which is an exciting development for us.
But don’t confuse miniLED with microLED, because, just like LCD and OLED, these technologies are quite different. Like OLED, microLED is an emissive display. In this design, small-sized LEDs of red, green, and blue are used to create an image with high brightness, enhanced color gamut, and very deep blacks. By most definitions, for a display to qualify as microLED, it must use <50μm chip, be package-free, and mass transferred onto the substrate. It involves a complex production process, so we’ve been expecting the technology to enter in the niche premium segment. This is proving to be the case with early market launches in unique sizes and high price points for now as companies improve the overall manufacturing cost.
An interesting aspect of microLED technology is its ability to be pieced together like a mosaic to create very large-size displays. Think airport arrival/departure signs or advertisements in Times Square. In this format, glass plays an important role in enabling an essentially seamless viewing experience. Glass and glass processing can allow the electronics that drive the panel to be printed along the edges, enabling larger viewing experiences in the tiles. For more on this, see Corning’s research on wrap-around electrodes on glass presented at SID Display Week 2020. Corning’s proprietary fusion process creates glass that provides a very smooth and dimensionally stable surface on which to transfer these microLEDs, which greatly improves the manufacturing efficiency.
The Buzz about QD
Finally, there’s quantum dot, or QD displays. There are many different versions of QD displays, from an LCD with a quantum dot film employed in the backlight, to emissive QD displays. The reason we see so much buzz about QD technology in the marketplace right now is because it has the potential to significantly improve picture quality in displays by also enabling rich colors.
We believe emissive QD displays are an exciting opportunity for Corning because they require two pieces of glass – one for the thin-film transistor (TFT) substrate and another for the color filter, or color conversion substrate, in the near term or an encapsulation substrate in the longer term. These QD displays offer the benefits of OLED in terms of thin form factor, wide viewing angle, and fast response time, while providing enhanced color performance and efficiency. Like microLED, we expect this technology to debut in the premium and niche segments.
Take the Long View with Corning
Corning has a proven track record of successfully navigating the display technology roadmap and making calculated decisions about which technologies to invest in. We’re excited about the many emerging opportunities across the display industry. We will continue to leverage our proprietary fusion manufacturing platform and reliable supply network to deliver exceptional quality glass substrates for a wide range of applications from the front plane through the backplane, to the backlight diffuser and beyond. Our existing portfolio of EAGLE XG, Astra, and Lotus NXT glasses are well-suited to support customers’ unique requirements from the low end to the harshest of processing temperatures. And we continue to innovate with materials, optics and glass processing to support the next generation of displays.
As we look forward, Corning is committed to innovating with our customers as the leading supplier of precision glass substrates for the displays of the future.
The Future of Corning Display