Wearables

Researchers create soft, weavable LED fibers for truly flexible wearable displays

Researchers create soft, weava...
Researchers have created an LED fiber that can be directly woven into textiles to form an integrated flexible display
Researchers have created an LED fiber that can be directly woven into textiles to form an integrated flexible display
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Researchers have created an LED fiber that can be directly woven into textiles to form an integrated flexible display
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Researchers have created an LED fiber that can be directly woven into textiles to form an integrated flexible display
The solution-dipping method of LED fiber creation is said to be compatible with processes in the textile industry
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The solution-dipping method of LED fiber creation is said to be compatible with processes in the textile industry
Dipped LED fibers glow brightly when a voltage is applied
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Dipped LED fibers glow brightly when a voltage is applied

Electronicdisplays for integration with clothing and textiles are a rapidly developing field in the realm of wearable electronics. However, flexible LEDs designed to form part of an elastic or deformable coating forclothing or apparel – even displays specifically designed to be directly bio-compatible – still rely on a hard substrate on which to layer theappropriate electroluminescent material. Now researchers at the Korea Advanced Instituteof Science and Technology (KAIST) have created a fiber-like LED thatcan be directly knitted or woven to form part of the fabric itself.

"Ourresearch will become a core technology in developing light emitting diodes onfibers, which are fundamental elements of fabrics," said Professor Choi, headof the research team at the School of Electrical Engineering at KAIST. "We hopewe can lower the barrier of wearable displays entering the market."

The solution-dipping method of LED fiber creation is said to be compatible with processes in the textile industry
The solution-dipping method of LED fiber creation is said to be compatible with processes in the textile industry

To producetheir LED strands, the scientists start with a fiber of polyethyleneterephthalate, which they then dip several times into a solution of PEDOT:PSS (poly(3,4-ethylenedioxythiophene)polystyrene sulfonate) and then dry at 130° C (266° F) for 30 minutes toready it for layering with organic materials. Once dried, the dipped fiber isthen re-dipped in a bath of super-yellow (poly-(p-phenylenevinylene) polymerorganic LED (OLED)) solution, dried again in an oven, and finally coated with a Lithium Fluoride/Aluminum (LiF/Al) compound.

Thisprocess, the researchers claim, is a much more efficient way of applying LEDmaterials to small cylindrical structures than any heat-treating method. By carefullyadjusting the extraction rate of the fiber from the solution, the researcherssay they can control the deposition thickness to within hundreds ofthousandths of a nanometer.

Dipped LED fibers glow brightly when a voltage is applied
Dipped LED fibers glow brightly when a voltage is applied

The researchers believe their method of producing LED fibers could be an acceleratorfor the commercialization of wearable displays because inexpensive, automated high-volume production of fibers using such textile manufacturing methods asroll-to-roll processing could be employed. In this way, LED fibers could be mass-produced as easily as nylon or polyethylene fiber is produced today.

"Thistechnology will eventually allow the production of wearable displays to be aseasy as making clothes," said Seon-Il Kwon, a member of the KAIST Electrical Engineeringteam.

The results of this work were recently published in the journal AdvancedElectronic Materials

Source: KAIST

5 comments
Bob Flint
Can you safely wear against the skin? Could your bodies electro/thermal energy power the strands? How well does it stand up to wear & washing?
kalqlate
I can imagine all kinds of sports and artistic performances being enhanced with suits made of LED fibers: ice skating, synchronized swimming, ballet, on and on...
Kpar
As is my wont, I see safer motorcycle clothing- perhaps even with brake lights/turn signals built in. The future is bright...
artmez
So how did they even discover this? Were they targeting fabric LEDs? If so, why? And how would one even accidentally discover this? Are those chemicals commonly used for other purposes? That's the bigger puzzle to me. It's not like Edison's lab where he had an idea and then set a legion of scientists working the light bulb. As a side note: Lithium is very bioreactive. Low, "monitored" doses are used to treat bipolar disorder. For some, Lithium can accumulate and when it does, it can lead to a host of really BAD problems.
Jayna Sheats
To answer some comments above, in case people actually look back at them (from someone who did years of R&D on organic LEDs in the 90s): The chemicals are not accidental: these are very well known in the industry and academica (have been used for decades, literally); there are no surprises there. As to lithium ions, it is no different from lithium batteries: the device would be useless if there was significant exposure to the elements. But as to "washing", etc., or any other practicality: totally unknown and probably totally unrealistic. Organic LEDs have to be protected extremely thoroughly against the tiniest amount of water (even oxygen hurts them), and so these will have to be covered with a coating that is already challenging to put onto flat panel displays. Companies like LG (the dominant commercial player with OLEDs today) have struggled to make economically viable flexible displays (these devices were known in R&D in 1987, by the way). The quality of this report is well illustrated by the sentence: "the researchers say they can control the deposition thickness to within hundreds of thousandths of a nanometer." First, "hundreds of thousandths" is pretty close to one; why not say "tenths"???? Second, it is scientifically absurd: a tenth of a nanometer is roughly the diameter of an atom, and no one, not even with the best vacuum deposition equipment, makes polymers with surfaces defined to an atom. They are actually moving on that scale (including for example the surface of the PET water bottle you might have around). This is a classic example of hype obscuring a technical achievement that, by itself, is certainly hard work and not to be denigrated (even if it is commercially useless, or will remain so for decades).