After dozens of press releases, emails and calls from industry contacts and PR people, it’s easy for an analyst to think he knows in advance what’s going to happen at SID Display Week. Then, there are the surprises.

Ken Werner
Senior Analyst and Editor

One of those surprises was encountered in the LG Display booth on the show floor, where a “QuantumRail” quantum-dot optical element from Nanosys (Palo Alto, CA; www.nanosysinc.com) had been incorporated in a developmental LCD LED backlight unit by LG Innotek.

Quantum dots have been under development for years, but they often seemed more promising as a Ph.D. dissertation topic than as a practical technology, at least as far display and lighting applications are concerned. QDs consist of a semiconductor nanocrystal core with a diameter between 2 to 12 nanometers. Surrounding the core is a semiconductor shell, and surrounding that is a polymer coating to which any of a variety of organic molecules may be attached.

The characteristics of a QD depend to some extent on those organic molecules but mostly they depend on the size of the dot. For lighting and display purposes, the characteristic of interest is that when the dot is excited by incoming light, it will emit light at a longer wavelength. That light can be emitted in a very narrow wavelength distribution, whose central wavelength is determined by the dot’s diameter. Once you have designed and made the dots, they can be distributed in a carrier ¬– an ink – and conveniently applied to appropriate surfaces, or incorporated into an optical component as Nanosys does.

At the IMS Market Focus Conference on The Future of LED Lighting and Backlighting yesterday, QD Vision described a recent commercial lighting application, in which a film of QDs is applied to the front surface of an LED PAR 38 flood lamp. Blue light from the LED is converted to red light with high efficiency, and the resulting mix of wavelengths produces a warm light similar to the light from an incandescent lamp. QD Vision calls the optical element that produces this result “Quantum Light,” which is available commercially now.

The backlight solution developed by Nanosys and LG Innotek uses a mixture of appropriately sized QDs to convert the light from a blue LED to tri-chromatic white light with highly saturated RGB primary color coordinates. This replaces the conventional “white” LEDs with a light that can generate a significantly larger color gamut.

As used in the 3.2-inch, 480×800 display shown in LGD’s booth, the QuantumRail solution raised the color gamut from 70% NTSC to 103% with no increase in power consumption, according to LGD. The luminance was 450 nits.

An LGD representative, who knew immediately where to take me when I asked to see the "quantum dot backlight," said the unit was a technology demonstration. This is one demonstration that looks like a potential product.

NOTE: This is a corrected version of the original Display Daily that originally appeared on May 27, 2010. The original version mistakenly attributed the quantum-dot element in the LG display to QD Vision instead of Nanosys.