Laser Display Challenges Cathode-Ray Tubes
James P. Smith
ORLANDO, Fla. -- A new display technology is looking to upstage the cathode-ray tube. Researchers at the University of Central Florida have developed a display that features a plastic screen peppered with crystalline powders that emit different colored light when zapped by a commercial diode laser. The display, according to the lead scientist, Michael Bass, shows such promise that it could end the long run of the cathode-ray tube and produce thinner displays at low cost.
Bass and his team have developed crystals that emit red, green or blue light when they are illuminated with a near-infrared diode laser. The crystals are ground into a powder and embedded in an inexpensive polymer sheet that can be produced in virtually any size.
Bass has prepared a small demonstration of the technology in his laboratory.
"We have proven the principle, and we know that, given the resources, we would be able to put together a two-dimensional display," he said.
Such a display would not require the depth of a cathode-ray tube display, and it would deliver higher resolution and brightness because it is not as susceptible to blooming.
The emitter materials are inorganic crystals doped with rare-earth ions. "The real trick is that in all of the host crystals there are ytterbium ions as co-dopants," Bass explained.
Ytterbium emits light in the near-IR, but when it is co-doped with other rare-earth elements, such as erbium, holmium, thulium or praseodymium, it transfers its energy to the other ions, which emit visible light.
The team has developed three materials as blue emitters below 480 nm and is investigating the possibility that polymers can produce even lower wavelengths. The researchers also have a 660-nm red-emitting material and two in the green, at 540 and 550 nm.
"We are open to partners and are actively looking for companies who would want to work with us to develop this display technology," Bass said.
"We have developed the materials for making a very nice display, but in order to take it to the next stage we need the technologies to make the displays." These technologies are not new; they include the deposition of the particles as red, green and blue pixels, and the conversion of the digital signal that represents an image into laser scanning and intensity modulations.
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