SmartPaper

In December, Macy's Bridgewater, N.J., department store will conclude a six-month pilot project in its children's department using signs made of SmartPaper. It's a new electronic paper made by Palo Alto, Calif.-based Gyricon Media Inc., and it allows Macy's to update displays in real time using wireless technology. The retailer is considering a rollout of the 11-by-14-inch SmartPaper signs in its other stores.

- In the 1970s, physicist Nick Sheridon, working at the Xerox Palo Alto Research Center, invented an electronic paper made up of electrically charged beads. Nearly 30 years later, Xerox spun off Gyricon Media Inc., which developed Sheridon's ideas to produce SmartPaper.

- Although produced in a roll, like real paper, the SmartPaper used at Macy's is actually two sheets of thin plastic with millions of solid, two-toned polyethylene beads in between.

- Each bead, smaller than a grain of sand, is tinted half-black and half white, and embedded in tiny cavities in a sheet of rubber surrounded by a liquid. The pigment on the white half is titanium dioxide. The black half uses carbon or other commercial black pigments. Each bead is electrically charged, and can rotate or gyrate -- hence the name Gyricon -- when an external electric field is applied.

- Depending on the charge, the balls flip black or white to form pixel-like segments that can be used to create text and images. Once the beads rotate, they'll stay that way until they are zapped again.

- Macy's staff key in price points, which are beamed to a miniature receiver inside each sign's one-inch base by remote control. A transmitter shoots back a message confirming the commands have been carried out, as the store's SmartPaper screens display the up-to-date prices.

- Macy's owners, Federated Department Stores Inc., now spend $250,000 a month changing printed signs across the U.S. Each e-paper sign, by contrast, costs roughly $100 (U.S.) -- the cost of installation, maintenance and support is yet to be determined.