Can Quantum Dots Save LCD-TV from AMOLEDs? – Ken Werner
- Published on Monday, 25 June 2012 10:56
- Pete Putman
- 0 Comments
As the Society for Information Display’s Display Week event was ramping up in early June, Nanosys Inc. and the Optical Systems Division of 3M Company announced they would collaborate to bring quantum-dot (QD) technology to consumer liquid-crystal displays.
Nanosys (Palo Alto, CA), which identifies itself as a materials company, has been working for several years to develop QD technology for display applications and has generated serious interest from companies such as Samsung and LG Innotek. But there has been a missing link, or two: a company that can produce commercial volumes of stable QD components and a company with high-volume supply-chain expertise. Given its experience in manufacturing display enhancement films of various kinds and effectively supplying them in high volumes to the consumer display industry, 3M is clearly in a position to fill both of these roles. Or, as Optical Systems Division VP Jim Bauman put it, “Combining the world-class technology and materials expertise of Nanosys with the engineering, design and supply chain capabilities of 3M will unlock a powerful new color viewing experience for consumers.”
Quantum dots are semiconductor spheres with diameters ranging from 2 nanometers to a few tens of nanometers. When an appropriately fabricated quantum dot is excited by optical radiation, it re-radiates at a longer wavelength that depends on the QD’s diameter. So, when irradiated by the light from, say, a blue LED, QDs of the appropriate sizes can re-radiate in the green and red. (If you make Sharp Quattron panels, you can get QDs that radiate in the yellow, too.) QDs have narrow emission spectra, so using them produces a light source that is more like RGB OLEDs than like a traditional backlight, and the center of the emission for each color can be precisely positioned. This makes it easy to dramatically expand the color gamut of backlit LCDs and to tailor the gamut precisely for various applications.
QDEF is a drop-in film that LCD manufacturers can integrate with existing production processes. The version shown at SID consists of a diffuser sheet coated with an appropriate mixture of quantum dots – trillions of them – which are protected from air and moisture by a recently announced barrier film made by 3M. QDEF is literally a drop-in replacement for the diffuser sheet, requiring no change in assembly procedures. But the use of QDEF allows the white LEDs in the backlight to be replaced with less expensive blue LEDs. Nanosys CEO Jason Hartlove has previously stated that the QD approach, in addition to expanding color gamut, produces a modest reduction in power consumption, all at a cost that is comparable to the conventional approach.
“We are working together to improve an area of display performance that has been largely neglected for the last decade,” said Hartlove. “Improving color performance for LCDs with drop-in solutions will bring a stunning new visual experience to the consumer and a competitive advantage to the LCD manufacturer against new display technologies such as OLED.”
This last point is not a throw-away. By narrowing the visual distance between LCDs and OLED displays without harming LCD’s considerable advantage in cost over the short and medium term, QDEF could have a potentially disruptive effect on the developing technology battle between LCDs and AMOLEDs.
Ken Werner is Principal of Nutmeg Consultants, specializing in the display industry and display technology. You can reach him at email@example.com.