You’ve probably seen cars painted with ‘optically variable pigments’ (OVP). The colour of the car varies depending on the angle you look at it.

Optically variable pigments have millions of microscopic plates dispersed in a liquid. When the paint dries, the liquid evaporates off leaving layers of microscopic plates. Because the plates are all the same size and shape, collectively they act like a diffraction grating. Theoretically a single colour OVP is also possible (like a butterfly wing).

If the size/shape of the plates in a single colour OVP could be actively controlled, the colour of the paint could also be controlled. I propose the plates could be made of bi-metallic sheets. When the temperature changes the plates change shape, thus the average separation of plates changes, thus the colour changes. Of course this would only work if the plates remained dispersed in the liquid.

A display could be made using this technique. Each pixel would be a transparent well containing the pigment. The temperature of each pixel would be controlled with a small heating element.
-- xaviergisz, May 23 2007

Thermochromism http://en.wikipedia...wiki/Thermochromics
[ldischler, May 23 2007]

NewScientist Article: Chameleon liquid could outshine LCDs http://www.newscien...-outshine-lcds.html
kind of similar, kind of different. [xaviergisz, Jul 17 2007, last modified Jun 13 2010]

Baked! http://www.mirasold...ys.com/how-it-works
It uses electrostatic forces to alter the pixels. [Aq_Bi, Jan 19 2011]

I don't know much about how this would work, but I know it would need a separate light source (similar to LCDs?), and it would probably have a very slow response time because it has to heat and cool tiny heating elements.

I don't know what a good use for this technology would be, compared to current technologies.
-- BJS, May 23 2007


needing a separate light source (or simply using ambient light) could be seen as an advantage (less power, display automatically adapts to ambient conditions etc.)

Heat is one way of changing the shape of the plates. With suitable materials this could also be done with electric or magnetic field.

This is essentially an alternative to standard e-paper technology. A good application might be animated billboards.
-- xaviergisz, May 23 2007


the effect of placing two glass plates on top of one another;slides,cover slips produces a phenpomenon known as Newton's rings squishing some LCDs has a similar effect maybe improving the content of advertising might make it less offensive and there for more attractive.
-- giligamesh, May 23 2007


I like the idea of dynamically controlling diffraction (or iridescence?). Presumably it would be very direction-sensitive?

Maybe the substance wouldn't need to be liquid - perhaps plates embedded in a flexible transparent matrix would work, and I'm sure - as you suggested - you could control it by other means than temperature.
-- MaxwellBuchanan, May 23 2007


Not exactly fast enough for video, but you could use it for advertising. And I'm sure it would make beautiful art displays too.
-- 5th Earth, May 23 2007


thanks for the link Aq_Bi, but 'mirasol' is more like another idea of mine - "piezoelectric display II".
-- xaviergisz, Jan 19 2011



random, halfbakery