Last month, Amazon released Kindle Fire HDX 7 — the first ever mobile device to feature a quantum-dot-enhanced display.
The 7″ display includes a Quantum Dot Enhancement Film (QDEF) produced by 3M in collaboration with Nanosys, Inc. Compared to the traditional LED-LCD display, the QDEF essentially replaces the YAG phosphor of the white LED backlight and functions as a high-efficiency photoluminescent emitter. The ODEF includes quantum dots of different sizes, which would emit different colors when excited due to quantum confinement effect. More detail of the QDEF can be found via the link below.
It is noted that the quantum-dot-enhanced display of Kindle Fire HDX 7 does not utilize the electroluminescent property of quantum dots, and thus is not actually a quantum dot light emitting diode (QLED). Nevertheless, it could signal the beginning of the mass commercialization of quantum dots technology in consumer markets.
And the very “best” of todays technologies? According to Displaymate, quote:
“The very best of today’s display technologies? The Quantum Dots displays used in the Kindle Fire HDX 7 according to the report.
Quantum Dots are almost magical because they use Quantum Physics to produce highly saturated primary colors for LCDs that are similar to those produced by OLED displays. They not only significantly increase the size of the Color Gamut by 40-50 percent but also improve the power efficiency by an additional 15-20 percent. Instead of using White LEDs (which have yellow phosphors) that produce a broad light spectrum that makes it hard to efficiently produce saturated colors, Quantum Dots directly convert the light from Blue LEDs into highly saturated primary colors for LCDs. You can see the remarkable difference in their light spectra in Figure 4. Quantum Dots are going to revolutionize LCDs for the next 5+ years.”
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How does QDEF work?
Nanosys QDEF™ enables deep color and high efficiency by providing displays with an ideal light source. How does it do that?
Each sheet of QDEF contains trillions of tiny (by tiny we mean: a bit bigger than a water molecule but smaller than a virus in size) nanoscrystal phosphors, called “Quantum Dots .” Not found naturally occurring anywhere on Earth, these “dots” can be tuned, by changing their size, to emit light at just the right wavelengths for our displays and do so very efficiently.
Unlike conventional phosphor technologies such as YAG that emit with a fixed spectrum, quantum dots can actually convert light to nearly any color in the visible spectrum. Pumped with a blue source, such as the GaN LED, they can be made to emit at any wavelength beyond the pump source wavelength with very high efficiency (over 90% quantum yield) and with very narrow spectral distribution (only 30 – 40nm FWHM.) The real magic of quantum dots is in the ability to tune the color output of the dots, by carefully controlling the size of the crystals as they are synthesized so that their spectral peak output can be controlled within 2 nanometers to nearly any visible wavelength.
For the first time, display designers will have the ability to tune and match the backlight spectrum to the color filters. This means displays that are brighter, more efficient, and produce truly vibrant colors.
How does it all come together?
Engineering the quantum dots to precise display industry specifications isn’t enough to revolutionize the way LCDs are experienced on its own. The dots need to be easily integrated into current manufacturing operations with minimal impact on display system design if they are to be widely adopted. To do this, Nanosys spent a lot of time working with major display manufacturers to get the packaging just right so that it would be a simple, drop-in product that did not require any line retooling or process changes. The end result is called Quantum Dot Enhancement Film or QDEF.
Designed as a replacement for the an existing film in LCD backlights called the diffuser, QDEF combines red and green emitting quantum dots in a thin, optically clear sheet that emits white light when stimulated by blue (some of that blue is allowed to pass through to make the B in RGB at the LCM of course). So manufacturers who’ve invested billions in plant and equipment for LCD production can simply slip this sheet into their process, change their ‘white’ LEDs to blue (the same LEDs but without the phosphor) and start producing LCD panels with the colors and efficiencies of the best OLEDs, at a fraction of the cost and current industrial scale.
Nanosys is currently shipping production samples to display manufacturers and is on track to begin producing at commercial volumes fall of 2013.