Flipping Pixels with Magnets
Researchers have created a mechanical screen that is programmed by magnetism and can display encrypted images without any electronics.
If asked what the best available display technologies are today, most people would probably bring up ultra-high-resolution monitors with blazing-fast refresh rates and response times. They might even pull out some tables comparing the specs of a number of the top options to prove which is truly the best. But this comparison may not be thorough enough to crown a victor. It is leaving out some very impressive displays, like, for example, the skin of a squid.
Say what now?!? It may seem odd at first to consider the skin of an animal to be a display, but not all displays must be LED-based. These amazing natural, flexible displays can perfectly camouflage a squid by matching their surroundings, or scare off predators by mimicking another creature. And believe it or not, these impressive transformations are all carried out by the contraction and expansion of pigment-filled sacs in the animal’s skin. Kind of makes you reconsider what exactly makes something a display, doesn’t it?
It did for a team of researchers at the University of Michigan, anyway. In response, they developed a very interesting type of screen that can display images — even encrypted images — all without the need for any electronics. Their purely mechanical technology is driven by magnetic fields. While many of the proposed use cases for this display seem a tad far-fetched, it is a thought-provoking creation all the same.
The display is made up of spherical beads, each serving as a pixel. Half of each pixel is orange, and the other half white. Microscopic magnetic particles within the beads cause them to react, by flipping one way or the other, when they are in the presence of a magnetic field. Both iron oxide and neodymium particles are included, which can be manipulated by weak or strong magnetic forces, respectively.
By exposing the device to a specific pattern of magnetism, the screen can be programmed to display an image. Simply shaking the display will then erase the image, much like an Etch-A-Sketch. But the programming remains, and when the screen is again in the presence of any magnetic field (not the complex pattern that it was programmed with), the image will reappear. By leveraging both weak and strong magnetic forces, the display can even be programmed to store multiple images.
It was also demonstrated that by exposing the display to a complex pattern of magnetic forces, an encrypted image could be encoded into the display. That message could then only be decrypted by exposing the screen to a proper “key,” that is, the correct magnetic pattern that would decrypt it. It was also shown that multiple encrypted images, each revealed by a different key, could be encoded into the device simultaneously.
So where does this technology go from here? The researchers envision their display being used in everything from clothing to stickers, ID badges, barcodes, and e-book readers, but only time will tell if it is actually practical for use in these types of applications.