Chroma: Hue changing materials
The Idea
Chroma is a smart material which changes the intensity of its colour depending on the voltage applied to it. It has been made by sandwiching an lcd shutter between a translucent coloured material and a reflective surface. Depending on the voltage applied the opacity of the LCD shutter changes and thus the amount of light reflected from it. Hence changing the perceived colour intensity.
The concept
Chroma is my exploration into developing smart materials through combining existing materials and technologies in interesting ways. These materials could form our future walls and future gadgets, thus enabling a much more subtle level of communication. They could form interfaces which are more distributed compared to the localized devices as we have now.
Such as: Embedding theses materials into the bodies of devices could let the whole device change color to indicate an event, they could be embedded in our living space , where they would serve to control its ambience. Many such uses are possible.
Design
I have made a very rudimentary prototype. You can see the working in the video below. Though the effect is not very visible due to imperfect fabrication, the concept is demonstrated.
The material has been made by sandwiching 4 layers as illustrated below.
Layer 1: The outer layer consisting of the translucent plastic which gives the strength and the basic hue to the combination. | Layer 2: Consists of a LCD shutter whose transmission coefficient can be varied with voltage applied. | Layer 3: This is the color filter used to allow a particular color to pass through to the last layer | Layer 4: Is a reflective layer to reflect the light back to the top surface.
Hence by controlling the voltage across the LCD shutter we can vary the perceived hue of the top layer as we are changing the amount of light passing through it to the reflective layer
A similar technique can be used with metal also. The trick being that the metal has to be etched with micro-perforations to pass light through it but the holes themselves being invisible to the human eye. You can see an example of such a metal foil here
Limitations
Might need extra layers to form support for very thin metal layers. Viewing angle influences the perceived hue .
Future Work
Other materials can be developed by etching and sealing electrochromic inks into metal. The metal itself acts as a carrier for electric current current thus activating the ink and changing the colour of the metal surface.
References
Programming Reality: From Transitive Materials to Organic User Interfaces – Marcelo Coelho, Ivan Poupyrev, Sajid Sadi, Roel Vertegaal et al.
Influence of the Ambient Light in the Optical Property of Reflective PDLC – KITA S(Toppan Printing Co., Ltd., Saitama, Jpn) MIYASHITA T(Tohoku Univ., Miyagi, Jpn) UCHIDA T(Tohoku Univ., Miyagi, Jpn)
Electrochromism and Electrochromic Devices by Paul Monk, Roger Mortimer, and David Rosseinsky.