Technology Review – A layer of nanomaterial that gives a liquid-crystal display the rich range of colors usually possible only with more expensive technologies will be commercialized later this year by the materials giant 3M and Nanosys, a private company in Palo Alto, California. Nanosys representatives say they are in talks with major display manufacturers to adopt the quantum-dot films, and that they will be in a 15.6-inch notebook computer available next year.
Liquid-crystal displays (LCDs) dominate the market for both televisions and portable electronics. For many years now, manufacturers have concentrated on making LCDs on a large scale at ever lower costs, to the point where they have become commodities. Meanwhile, more expensive display technologies based on organic light-emitting diodes (OLEDs) have come along, offering richer color and, in some cases, better power consumption, but at a higher price.
Representatives from Nanosys say their film—a sheet of plastic embedded with nanoscale spheres of indium-phosphide and cadmium quantum dots—makes it possible to match the color gamut of an OLED in an LCD, without any changes to the manufacturing process, and without adding much cost.
Nano boost: A film loaded with quantum dots (left) can be added to an LCD to improve its color gamut. The film converts some of the blue light emitted by the screen’s backlight (right) into red and green light. Nanosys
The LCDs used in today’s portable electronics use white light from a set of light-emitting diodes at the edges of the device. Liquid-crystal shutters guide the light, and color filters add hue to it. White light sources are expensive, so these displays use blue light-emitting diodes coated with phosphors that convert their output into white light.
The Nanosys-3M film simply takes the place of the phosphor in this stack of components. Quantum dots in the film convert about two-thirds of the blue light from the backlight into red and green light. Compared to the white light from a conventional LCD, more of the red, green, and blue light passes through the color filters, and the images are brighter and more richly colored.