Nanosys has developed an add-on for blue LED display backlights that converts some of the blue light into red and green light of narrowly defined wavelengths selected to match the LCD’s filters. The company’s “quantumrail,” a thin capillary that can be attached to a backlight, contains a suspension of quantum dots that convert the light.
Quantum dots get their name from their unusual properties: when structured at the nanoscale, the optical and electronic properties of certain semiconducting materials such as cadmium are dictated by their dimensions. Conventional semiconducting materials emit light of a particular color when they’re bombarded with electrons or photons–this is how light-emitting diodes work. By carefully controlling the dimensions of quantum dots at the nanoscale, it’s possible to precisely tune what color light they emit.
Researchers have been making quantum dots since the 1980s, but it’s only this year that these nanomaterials have been incorporated into consumer products. MIT spinoff QD Vision was the first to market with a consumer product. Its quantum dots are incorporated into energy-efficient LED lighting made by Nexus. They convert light from an LED into a mixture of colors that’s more pleasing to the eye. Company CTO Seth Coe-Sullivan says QD Vision is also working with major display companies to incorporate quantum dots into LCD backlights. Coe-Sullivan says these products will launch next year.
The displays incorporating Nanosys’s quantumrail that were exhibited at the conference in Seattle had a better color gamut than traditional LCDs. A good notebook display can generate 72 percent of the colors dictated by a commonly used measurement of color gamut called the National Television System Committee standard, but the LG display rates 103 percent–that is, it can show colors that aren’t included in this standard. Running the display at lower power to create a 72 percent color gamut can add 10 percent to the battery life, according to Nanosys.