A new kind of 3D display could take the form of an acrylic cube with an image inside, which can be erased and rewritten to easily. The new technique can be used to make 2D, 3D and even animated images.
The new display starts with a basic PDMS polymer, which is treated with a chemical “switch” that makes it sensitive to light. The active ingredient in the switch is a compound called azobenzene, paired with boron difluoride to boost its reactivity to light.
This chemical switch is activated when red light is shone on it, so an image can be etched into the polymer by projecting an image in red light onto it. Blue light or a little bit of heat can reset the image, allowing it to be rewritten easily.
The team tested it in a few different ways. Two-dimensional images can be drawn onto thin films of the treated polymer pretty easily, as seen in the image of a dog above. But it gets cooler when projected into a cube 6 in (15 cm) thick – by projecting light at the cube from different angles, an image can be built up in 2D slices to form a 3D image. The end result kind of looks like an object is suspended inside the cube. And again, hitting the cube with blue light or heat erases the image, ready for the next one.
The researchers suggest these rewritable, handheld 3D displays could find applications in architectural plans, or even showing medical scans of organs or bones in three dimensions.
“This is like 3D printing that is reversible,” said Ivan Aprahamian, co-corresponding author of the study. “You can take any polymer that has the optimal optic properties – that is, it’s translucent –and enhance it with our chemical switch. Now that polymer is a 3D display. You do not need virtual reality headsets or complicated instrumentation. All you need is the right piece of plastic and our technology.”
Cooler still, the team found that they could animate the 2D images in a 3D cube, by projecting multiple 2D images as frames. When you turn the cube, it looks like the image is moving. It’s an intriguing idea, and one the researchers say will only get better with more research.
“Scaling up requires tuning the chemical switch properties to improve resolution, contrast, and refresh rate,” said Alex Lippert, co-corresponding author of the study. “The projector system can in principle be scaled up and developed into a turnkey system with automated hardware and associated software for easy use.”
The research was published in the journal Chem.
Source: Dartmouth College