Imagine if you were a product designer who wanted to see what an actual physical object would look like in different colors or patterns. Well, MIT has designed a system that allows users to easily do just that, utilizing photochromic dyes.
Known as ChromoUpdate, the experimental new technology is being developed by a team led by postdoctoral student Michael Wessley. It builds upon a previously developed system by the name of PhotoChromeleon.
In the latter setup, objects were spray-painted with an ink made of a mixture of cyan, magenta, and yellow light-sensitive dyes. When the object was subsequently exposed to an ultraviolet LED light source, all of those dyes were simultaneously activated (or "saturated"), producing one solid color.
Next, a projector was used to shine patterns of different wavelengths of visible light onto the object. Depending on its wavelength, that light deactivated (or "desaturated") one or more of the dyes in specific areas, turning them transparent. As a result, that part of the object took on the color of the dyes that weren't deactivated.
Even when exposed to regular indoor or outdoor light, the object retained its new coloration. If users wanted to start again from scratch, though, they simply "erased" the current color pattern by re-exposing the object to the ultraviolet LED light.
While it was a clever system, it reportedly took approximately 20 minutes to produce the color patterns and images. By contrast, ChromoUpdate only takes a few minutes for color images, and just seconds for black-and-white previews of designs.
Instead of beginning by exposing the whole surface of the dyed object to the ultraviolet light, it starts right in with a projected pattern of UV light. The intensity of that light varies within different areas of that pattern, causing one or more of the dyes in those areas to be activated, taking on their given colors. Because the rest of the object isn't exposed to any of the UV light, though, the dyes covering it remain transparent.
Not only is this setup faster than PhotoChromeleon, but it also allows for much finer control of coloration. And although ChromoUpdate currently only works on items with smooth, hard surfaces, the scientists are working on adapting it to other types of material – possibly even fabric, for clothing that can be reprogrammed with different colors and patterns as desired.
The technology is demonstrated in the video below.
Source: MIT
