Researchers at the University of Tokyo have dusted off some e-ink technology originally developed back in the 1970s to create a new kind of easily erasable whiteboard technology that can be written on using magnetic pens instead of dry-erase markers.
If you're unfamiliar with how the black and white e-ink displays in devices like the Kindle work, the technology is actually fairly rudimentary. Microparticles measuring about 0.1mm are black on one side, and white on the other. And those two distinct hemispheres each carry a positive or negative charge. When placed between a pair of electrodes, the addition of an electrical charge on either side can then selectively flip each microparticle, essentially turning them into individual pixels to reveal a complex image.
To make their new writable display technology, the University of Tokyo researchers embedded the black side of those microparticles with even smaller magnetic nanoparticles. So as a magnet about as strong as the ones stuck to your fridge are passed over it, the black and white microparticles are flipped to their black side, leaving a visible trail behind. The technology is not that different than the Magna Doodle toy we all grew up, just considerably more refined.
The new e-ink whiteboards are not only durable and cheap to produce, but they can also be instantly erased at the push of a button with the addition of an electrical charge on the underside. Removing the need for erasers that always seem to go missing, or ever having to clean the board after an image has been left on it for a prolonged period.