Corning’s newest display glass innovation – Corning® Astra™ Glass – fills an important niche in the evolving world of high-performance displays. Manufacturers will use the glass as a substrate in panels for large-screen 8K TVs and other high-performance devices, meeting the demands of customers who want the most lifelike display imagery possible.
As an oxide display glass, Astra Glass serves as a foundation for extremely bright, high-resolution images with true-to-life refresh rates – in other words, pictures so realistic they virtually immerse the viewer in the on-screen experience.
This doesn’t happen with ordinary glass.
Astra Glass is specifically engineered to meet the evolving, rigorous requirements of oxide panel production.
Where does Astra Glass fit in the broader world of display production?
Display glass substrates each have a unique composition and tend to take their names from the type of thin-film transistors (TFTs) deposited on their surface – which, in turn, make up the image-generating pixels. Transistor material is important, because it defines how quickly the transistors turn off and on as they create moving images.
For many years, the preferred transistor material for the LCD industry has been amorphous silicon – called a-Si for short. A-Si transistors work beautifully in this application, even up to resolutions of 8K. Corning® EAGLE XG® Glass has led the industry as a substrate for a-Si panels since 2006. EAGLE XG Glass is expected to continue to support the evolution 8k displays over the coming years. However, in some areas the technology necessary to deliver 8K displays is evolving and this evolution is requiring some panel makers to use glass substrates with even-higher levels of thermal and dimensional stability.
As very high-resolution handheld devices requiring faster responses and lower power consumption came into development, transistors for these specific needs began to develop, too.
A different material – low-temperature polysilicon, or LTPS – proved up to the task, but required glass substrates to endure temperatures of up to 600 degrees Celsius, much hotter than the a-Si panel. Corning Lotus™ NXT Glass, widely available since 2013, gives manufacturers the ideal option for these LTPS mobile electronics devices.
Between a-Si and LTPS is the oxide TFT, a transistor technology considered an upstart just a few years ago.
Oxide TFTs are now being adopted by a growing number of panel manufacturers for both organic light-emitting diode (OLED) displays and liquid crystal displays (LCD) with higher electron mobility than amorphous silicon. Oxide panels offer brighter, sharper resolution than a-Si panels and a lower production cost than LTPS, making them well-suited for enabling 8K televisions and other high-performance devices.
Similar to LTPS, this new oxide transistor material requires high-temperature manufacturing processes – in some cases, more than 300-400° Celsius. This puts tough requirements on the glass holding the transistors. It simply can’t change shape, even under such high temperatures.
Here’s where Astra Glass comes into play for panel makers as they explore ways to meet changing consumer demands.
Corning Astra Glass serves oxide TFT manufacturing with a precisely engineered, pristine, flat surface and remarkable thermal stability. That means it’s able to withstand high temperatures with minimal sagging, warping, or changing dimension.
Why is thermal stability such an important aspect of display manufacturing?
In an 8K television panel, the TFT substrate, or backplane, must carry almost 8,000 pixels (hence the 8K moniker) across the screen.
The glass should not sag or expand, even at a microscopic level. If it does, the precise registry between the TFT substrate and its glass companion, the color filter substrate, would lose their seamless integration, compromising the brilliance and speed of the images on screen.
What other aspects of Astra Glass make it an attractive option for electronics manufacturers?
Corning’s proprietary fusion-draw process results in pristine surface quality at thicknesses of a half-millimeter or less. There’s very little, if any, variation in total thickness of the sheet, even across a wide expanse – an essential requirement for oxide display glass.
Astra Glass is also optimized to reduce sludge during the customer etching process – especially important in smartphone and tablet production. This helps lower both waste and customer costs, both factors that should help support the growing affordability of 8K technology.
As the TV industry evolves, Astra Glass will be a crucial component in both oxide LCD and OLED TVs, as well as in high-performance notebooks and tablets. As part of Corning’s display glass portfolio, it gives panel makers even more options, helping usher in a future of stronger, thinner, faster images with richer colors and an immersive experience across a wide array of devices.