Inspired by squid and octopuses, the new screen stores and displays encrypted images without electronics!

A flexible screen, partly inspired by squid, can store and display encrypted images like a computer, using magnetic fields, not electronics. The study was published in the journal Advanced Materials by engineers at the University of Michigan.

"This is one of the first cases when mechanical materials use magnetic fields for system encryption, information processing and calculations. And unlike some earlier mechanical computers, this device can be wrapped around the wrist," said Jörg Lahann, professor of chemical engineering at Wolfgang Pauli University and co-author of the study.

The researchers' screen can be used wherever light and power sources are cumbersome or unwanted, including clothing, stickers, identity cards, barcodes and e-books. One screen can show an image that everyone can see if placed next to a standard magnet, or a private encrypted image if placed above a complex array of magnets that acts as an encryption key.

"This device can be programmed to display certain information only when entering the correct keys. And there is no code or electronics that can be hacked," said Abdon Pena-Frances, associate professor of the Department of Materials Science and Engineering at UM and co-author-correspondent. "It can also be used for color-changing surfaces, for example, on disguised robots."

Shaking the screen erases the image on the display - like Etch-A-Sketch - except that the image is encoded in the magnetic properties of the beads inside the screen. It is restored when the display is exposed to a magnetic field again.

Beads act as pixels, switching between orange and white hemispheres. The orange halves of the beads contain microscopic magnetic particles that allow them to rotate up or down when exposed to a magnetic field, providing the color contrast necessary to display the image.

The effect of the magnet on the pixels will program them to show either white or orange in an attractive or repulsive magnetic field - a state called their polarization. For some pixels made of magnetic iron oxide particles, polarization can be changed using relatively weak magnetic fields. But the polarization of pixels, which also include neodymium particles, is more difficult to change - a strong magnetic impulse is required.

This screen stores and displays encrypted images without electronics.

Approaching the screen to an array of magnets of different strength can overwrite the magnetic properties of pixels in the target areas of the screen. Different arrays of magnets will program different images in the device. Credit: Jeremy Little, Michigan Engineering

A flexible screen, partly inspired by squid, can store and display encrypted images like a computer, using magnetic fields, not electronics. The study was published in the journal Advanced Materials by engineers at the University of Michigan.

"This is one of the first cases when mechanical materials use magnetic fields for system encryption, information processing and calculations. And unlike some earlier mechanical computers, this device can be wrapped around the wrist," said Jörg Lahann, professor of chemical engineering at Wolfgang Pauli University and co-author of the study.

The researchers' screen can be used wherever light and power sources are cumbersome or unwanted, including clothing, stickers, identity cards, barcodes and e-books. One screen can show an image that everyone can see if placed next to a standard magnet, or a private encrypted image if placed above a complex array of magnets that acts as an encryption key.