Taking off the mask

Kateeva’s other system offers an improvement over the traditional vacuum thermal evaporation (VTE) technique - usually somewhere in the middle of the production line - that uses shadow masks (thin metal squares with stenciled patterns) to drop red, green, and blue OLED materials onto a substrate.

Much like conventional TFE processing, VTE involves placing a substrate inside a vacuum chamber, and spraying through the shadow mask a vapor of OLED material in precise patterns of red, green, and blue. But materials are wasted when the vapor is sprayed on the mask and chamber. Coating the chamber and mask can also lead to particle contamination as the material flakes off, so excessive cleaning maintenance is required, Madigan says.

This isn’t necessarily bad for making small, smartphone screens: "If a substrate sheet with, say, 100 small displays on its surface has five defects, you may toss five, and all the rest are perfect," Madigan explains. And smaller shadow masks are more reliable.

But manufacturers start to lose money when they’re tossing one or two large-screen displays due to particle contamination or defects across the substrate.

Kateeva’s system, which, like its TFE system, is enclosed in a nitrogen chamber, precisely positions substrates - large enough for six 55-inch displays - beneath print heads, which contain hundreds of nozzles. These nozzles are tuned to deposit tiny droplets of OLED material in exact locations to create the display’s pixels. As Madigan explains: "Doing this over three layers removes the need for shadow masks at larger scales"

As with its YIELDjet FLEX system, Madigan says this YIELDjet product for OLED TV displays can help manufacturers save more than 50 percent over traditional methods. In order to further optimize the system for volume production, Kateeva partnered with Sumitomo, one of the leading OLED- materials suppliers.

Revolutionizing at MIT

The idea for Kateeva started in the early 2000s at MIT. Over several years, Madigan, Bulovic, Schmidt, Chen, and Leblanc had become involved in a partnership with Hewlett-Packard (HP) on a project to make printable electronics.

They had developed a variety of methods for manufacturing OLEDs - which Madigan had been studying since his undergraduate years at Princeton University. Other labs at that time were trying to make OLEDs more energy efficient, or colorful, or durable. "But we wanted to do something completely different that would revolutionize the industry, because that’s what we should be doing in a place like MIT," Madigan says.

However, HP pulled out of the project. "That left all this novel intellectual property sitting on a shelf that may never be used again," Bulovic exposits. Instead of letting those patents go to waste, the researchers decided to launch Kateeva in 2008, in order to commercially tackle OLED manufacturing.

A few years before, Bulovic had cut his teeth in the startup scene with QD Vision - which is currently developing quantum-dot technology for LED television displays - and was able to connect the group with local venture capitalists.

Madigan, on the other hand, was sharpening his entrepreneurial skills at the MIT Sloan School of Management. Among other things, the Entrepreneurship Lab class introduced him to the nuts and bolts of startups, including customer acquisition and talking to investors.

Additionally, Innovation Teams helped him study markets and design products for customer needs, laying the groundwork for starting a new company. As Madigan explains: "There was no handbook, but I benefitted a lot from those two classes."

In 2009, just when OLEDs were starting to gain mainstream popularity, Kateeva launched T-Jet, a precursor to YIELDjet. In that system, nozzles would drop OLED materials onto a plate, etched with a certain pattern. The plate was heated to 100 degrees Celsius to dry the ink, brought close to the substrate without touching it, and heated to 300 °C to transfer the dry, patterned vapor onto the substrate. "It was a cool concept, but inkjet was still cheaper," Madigan says.

So in 2012, Kateeva pivoted, switching gears to its YIELDjet system. Today, the system is a platform, Bulovic says, that, in the future, can be tweaked to print solid stage lighting panels, solar cells, nanostructure circuits, and luminescent concentrators, among other things. "All those would be enabled by the semiconductor printer Kateeva has been able to develop," he says. "OLED displays are just the first application."

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