The miniature color displays can be produced at costs far below those of LCD (liquid crystal display) panels, Siemens said.

The technology could be used to show information about products or provide step-by-step instructions directly on the packaging with the press of a tiny button.

The flexible miniature displays consist of an electrochromic material that holds a pattern of electrodes; a conductive plastic foil serves as the other electrode and the transparent window. The electrochromic substance changes color when an electrical voltage shifts charges in its molecules.

For their current tests, Siemens scientists are using silicon switching elements to control the device, but the aim is to use a printing process to manufacturer the entire display, including the appropriate control electronics such as conductive and semi- conductive plastics.

The displays can obtain their energy from printable batteries, which are already available, according to Siemens. But since these batteries last only for a few months, the miniature display technology is only feasible for merchandise with high turnover rates or short-use durations, Siemens said.

Another local energy source could be printed antennas that receive pulses from a transmitter in the shelf and convert the pulses into electricity, the manufacturer said.