As a follow up to a previous blog entry, I wanted to expand on Opalux, who has developed a new technology for color e-paper. The technology called P-ink for Photonic ink uses structured photonic crystals to produce colors, which the company says are electronically tunable across the entire visible spectrum and beyond. The company was co-founded by André Arsenault Ph.D., a chemist at the University of Toronto. Joining Dr. Arsenault are several other chemists from the University including: Ulrich Kamp, PhD., Assaad Ghoussoub, PhD. and Daniel Puzzo. The technology itself was developed by Arsenault in conjunction with Geoffrey Ozin and Daniel Puzzo at the University of Toronto and Ian Manners at the University of Bristol in the U.K.

The technology is comprised of pixels made from photonic crystals similar in structure to the natural gemstone opal. Each crystal (made from silicon microspheres) both blocks certain wavelengths of light and reflects others. To alter the color of the pixel, the material is stretched to change the space between the microspheres. According to the company, what differentiates the device is that the whole spectrum of colors-even ultraviolet and infrared light-can be produced by using only incident light.

This characteristic enables two very significant features of the device. First, the expensive color filters used with other color display technologies are not needed. And second, since the displays can be read using incident light, there is no power lost on backlighting. This latter feature also means that the displays can be read in sunlight as well as indoor lighting conditions similar to other electronic paper technologies.

In addition, the colors that can be produced are said to be brighter and more intense. In other electronic paper technologies, the color images are not up to par because each pixel is limited to a single primary color. Thus, for any color display, the pixels have to be arranged in groups of threeone for red, blue and greenand multiple colors can be generated by varying the intensity of each pixel within the grouping. Since the new technology claims that it can tune each pixel to any color, it could increase the intensity of all the colors generated.

In the device, photonic crystals approximately 200 nanometers in diameter are embedded in a porous electroactive polymer, which is in turn is sandwiched between a pair of electrodes with an electrolyte fluid. Applying voltage draws the electrolyte into the polymer, causing it to expand. The refractive index of the beads is caused by the change in their spacing in the polymer. A longer distance means an increase in reflected wavelengths. Moreover, the technology is claimed to be bistable. That means that once it changes color, it remains that way until another color change requires additional power.

The company is targeting signage displays as its initial application. It predicts that commercialization is approximately two years away. Interestingly, E-Ink announced a breakthrough in its technology relating to color displays at the SID conference in the spring. E-Ink also predicted that commercialization would take several years.

What is more interesting to me is that E-Ink has the resources, the strategic partnerships and the scale-up/manufacturing expertise behind them to make such a prediction. On the surface, Opalux seems to have none of those. On its web site, it notes it is seeking strategic partners to develop the technology for entrance into the signage market. Part of the work that needs to be done is a prototype. On the surface, the concept is definitely an exciting and promising one. However, the proof is in the pudding&or in this case, the prototype and then the commercial display product.