Engineers create squid-inspired magnetic screen for encrypted displays

Researchers have developed a flexible screen inspired by squid that can store and display encrypted images using magnetic fields instead of traditional electronics.

The screen can display a visible image near a standard magnet or a private encrypted image when aligned with a specific magnetic pattern that functions as an encryption key.

A team at the University of Michigan claims its screen is versatile for applications where light and power sources are impractical, such as in clothing, stickers, ID badges, barcodes, and e-book readers.

“It’s one of the first times where mechanical materials use magnetic fields for system-level encryption, information processing and computing. And unlike some earlier mechanical computers, this device can wrap around your wrist,” said Joerg Lahann , professor of chemical engineering at the University and co-corresponding author of the study, in a statement.

Flexible screen innovation

Similar to an Etch-A-Sketch, shaking the screen erases the display; however, the image is recorded in the magnetic qualities of the beads inside the screen. When the display is subjected to the magnetic field once more, it reappears.

The beads alternate between orange and white hemispheres, functioning similarly to pixels. The beads’ orange halves are filled with tiny magnetic particles that, when subjected to a magnetic field, cause the beads to rotate up or down, creating the color contrast required to display a picture.

Exposing the pixels to a magnet can program them to display either orange or white in a pushing or pulling magnetic field; this is known as their polarization.

Relatively low magnetic fields can alter the polarization of some pixels composed of iron oxide magnetic particles. However, the polarization of pixels containing neodymium particles is more difficult to modify; a powerful magnetic pulse is needed.

One may deliberately alter the polarization in certain regions of the screen by holding it over a grid of magnets of varying strengths and orientations. This will cause some pixels to flip orange while others will flip white when exposed to the same magnetic field orientation. An image is encoded in this manner.

“This device can be programmed to show specific information only when the right keys are provided. And there is no code or electronics to be hacked. This could also be used for color-changing surfaces, for example, on camouflaged robots ,” said Abdon Pena-Francesch, U-M assistant professor of materials science and engineering and co-corresponding author.

Squid-inspired pixels

A standard weak magnetic field, like that from a regular magnet, can reveal the image. Nonetheless, private images can be exhibited with a second magnetic grid that selectively modifies how some regions of the screen flip since iron oxide particles can be reprogrammed with comparatively weaker fields.

According to researchers, the iron oxide pixels display the public image when they are placed back onto the normal magnet and polarization returns to its initial state.

The researchers determined the screen’s resolution by measuring the expansion and contraction of pigment sacs in the skin of squids and octopi.

“If you make the beads too small, the changes in color become too small to see. The squid’s pigment sacs have optimized size and distribution to give high contrast, so we adapted our device’s pixels to match their size,” said Zane Zhang, U-M doctoral student in materials science and engineering and the study’s first author, in a statement .

The details of the team’s research were published in the journal Advanced Materials .