3D printed OLED Display

Researchers successfully 3D printed a flexible OLED display. This could allow anyone to mass-produce low-cost OLED displays using 3D printers, instead of by technicians in expensive microfabrication facilities. OLED panels are made from organic materials that emit light when electricity is applied through them. Since OLEDs do not require a backlight and filters (like LCDs do), they are more efficient, simpler to make and test in a product testing lab, and much thinner, and, in fact, can be made flexible and even rollable.

The plastic, organic layers of an OLED are thinner, lighter and more flexible than the crystalline layers in an LED. OLEDs enable a greater contrast ratio and wider viewing angle compared to LCDs, because OLED pixels emit light directly. OLEDs do not require backlighting like LCDs. OLEDs are easier to produce and can be made to larger sizes. OLEDs also have a much faster response time than an LCD. At first, there was a huge price gap between OLED TVs and premium LEDs. In fact, OLED used to mean “only lawyers, executives, and doctors” could afford them. However, the price of OLEDs have been steadily decreasing due to technological advancements and better product testing lab facilities.

“OLED displays are usually produced in big, expensive, ultra-clean fabrication facilities,” said Michael McAlpine, a University of Minnesota Kuhrmeyer Family Chair Professor in the Department of Mechanical Engineering and the senior author of the study. “We wanted to see if we could basically condense all of that down and print an OLED display on our table-top 3D printer, which was custom built and costs about the same as a Tesla Model S.”

A 3D printer builds an object from a digital 3D model. The team had tried 3D printing OLED displays, but they couldn’t make the light-emitting layers uniform. Before, other groups had printed OLED displays but only partially.

In the material testing lab, the University of Minnesota research team combined two different modes of printing to print the six device layers that resulted in a fully 3D-printed, flexible organic light-emitting diode display. The electrodes, interconnects, insulation, and encapsulation were all extrusion printed, while the active layers were spray printed using the same 3D printer at room temperature. The display prototype is about 1.5 inches on each side and has 64 pixels. Every pixel works and displays light.

“I thought I would get something, but maybe not a fully working display,” said Ruitao Su, the first author of the study and a 2020 University of Minnesota mechanical engineering Ph.D. graduate who is now a postdoctoral researcher at MIT. “But then it turns out all the pixels were working, and I can display the text I designed. My first reaction was ‘It is real!’ I was not able to sleep the whole night.”

Su said “the 3D-printed display was also flexible and could be packaged in an encapsulating material, which could make it useful for a wide variety of applications.”

“The device exhibited a relatively stable emission over the 2,000 bending cycles, suggesting that fully 3D printed OLEDs can potentially be used for important applications in soft electronics and wearable devices,” Su said.

“The nice part about our research is that the manufacturing is all built in, so we’re not talking 20 years out with some ‘pie in the sky’ vision,” McAlpine said. “This is something that we actually manufactured in the lab, and it is not hard to imagine that you could translate this to printing all kinds of displays ourselves at home or on the go within just a few years, on a small portable printer.”

The researchers said the next steps are to 3D print OLED displays that are higher resolution with improved brightness. 

Reference: Read the entire research paper at the Science Advances website.

Source: https://www.sciencedaily.com/releases/2022/01/220107164610.htm