A step beyond transparent display, soap bubble displays are actually something possible. Ultrasonic vibrations shot through the soap bubble display alter the images’ texture. More than just a two-dimensional display, these kinds of displays could even create a 3D image if stacked properly.
The bubble mixture is somewhat more complex than what is used to entertain children, but soap remains the main ingredient. The surface of a soap bubble is a micro membrane, which allows light to pass through it and displays its color on its structure. Yoichi Ochiai reported some of his team’s findings on his blog.
The team developed an ultra-thin and flexible BRDF (bidirectional reflectance distribution function, a four-dimensional function defining how light is reflected at an opaque surface) screen using a mixture of two colloidal liquids. The colloidal display varies in transparency and reflectance. Ochiai and Keisuke Toyoshima from the University of Tsukuba in Japan collaborated with Alexis Oyama from the Carnegie Mellon University in the US.
The system was controlled using ultrasonic sound waves, which altered the texture of the image, making it look rough or smooth. When the sound wave’s frequency was changed, they changed the transparency of the image. A combination of ultrasonic waves and ultra-thin membranes create a more realistic, distinctive, and vivid imagery, states Ochiai.
The bubble is harder to burst than a regular soap bubble, and it even allows objects to pass through it without popping it.