There's a lot of hope for displays made from organic light-emitting diodes, a.k.a. OLEDs. They provide better color, higher contrast and are more energy-efficient than the LCDs that currently provide displays for pretty much every television and computer. Many think OLED displays could supplant LCDs within the next five years. But there's a problem: OLEDs are challenging to make, so mass production has been a distant dream.
...until now. The engineers at the equipment company Kateeva have recently launched with what they think is the solution to significantly push OLEDs ahead. And they are doing it with an old technology: ink-jet printers.
But let's back up to how OLEDs are made. First it requires a backplane, otherwise known as a switching and driving circuitry, on a substrate like glass or plastic. And a tool needs to deposit organic layers on the substrate in very specific and precise patterns.
The current method of producing OLED displays uses as evaporation process, where the organic materials are precisely deposited onto a glass sheet through a thin metal stencil, or what is known as a "shadow mask." Problem is, a lot of material is wasted because it also lands all over the mask, in addition to where it's supposed to be.
There is also a lot of room for error. OLEDs are very sensitive to contamination, and just the process placing and removing the mask leaves the sheet open to dust contamination. So you need a way to get the extreme precision deposits that are possible with a mask, but without the need of a mask. This is where ink-jet printing comes in.
Kateeva has developed a platform called YIELDjet, which can position glass or plastic under print heads that can then custom print on sheets large enough for 55-inch displays. Each head has hundreds of nozzles that deposit droplets onto the sheets that build up the pixels of a display. This is essentially the same technology that is used in ink-jet printers.
To be sure, other companies, like Epson, have tried ink-jet printing technology to make OLED displays before, but none have managed to scale up to mass production. Again, the issue is contamination: Printing reduces particle contamination by removing the need for a mask but production of larger displays still presents a challenge. The Kateeva engineers have created a system that apparently "sweeps away" dust particles and the process is done entirely within a nitrogen chamber, where there is little to no exposure to air and moisture. And this allows them to produce the largest displays with low risk.
Now that there may be real promise for OLED displays at a reasonable cost, and the fact that plastic sheets allow for paper-thin products in any shape, the folks at Kateeva say, "...the applications are limited only by the imagination of today's product designers." So time to get thinking!