According to the NewScientist, full-colour photonic crystal displays could be on the market within two years. A team of Canadian researchers have developed a reflective display based on silica microspheres which can produce the whole visible spectrum without the need for colour filters.
The researchers stretch the crystals by bonding them to an electroactive polymer that expands when a voltage is applied to it, causing a change in the crystal structure. “By gradually increasing the voltage, we can span the whole visible spectrum, and even the UV and IR ranges. Such full-colour tuning is unprecedented,” says Arsenault, who has co-founded a start-up company called Opalux to commercialise the technology.
The crystals could be used to make full-colour flexible electronic paper, small displays, and large roadside billboards, say the researchers. But this will involve scaling up the process, a task that has proven challenging for other display technologies.
The work was published in Nature Photonics.
[Update:]
The Opalux web page has a few more details on the P-Ink (photonic ink) display technology:
The materials are based on highly reflective synthetic opal. Colors produced are brilliant and pure. Other features:
1. Full color display from single material for low materials and production cost.
2. Meet signage needs in size from shelf edge to highway billboards.
3. High brightness, peak reflectivity up to 95%.
4. Low power consumption.
Low voltage and current during switching.
Minimal power consumption when image is static.
5. Sub-second switching speed.
6. Heat management through controllable IR reflectivity.
7. Applicable on rigid or flexible substrates.
8. Lightweight, rugged, durable, and damage tolerant.
9. Costs scales only linearly with size.

