Electrocrystallochromic display and element

A device for controlling the color of light reflected in response to illumination by a polychromatic source of light, comprising:

• a reference reflective surface facing said source of light, said reference reflective surface having first and second dimensions, at least said first dimension being on the order of a wavelength of visible light, said reference reflective surface being oriented to reflect light from said source of light;
• a first electrostrictive element including a second reflective surface having first and second dimensions, said first dimension of said second reflective surface being on the order of a wavelength of visible light, said second reflective surface being located contiguous with said reference reflective surface, said first electrostrictive element including first and second electrodes adapted for receiving electrical potential, said first and second electrodes being located and spaced on said first electrostrictive element for causing said second reflective surface to move, in response to application of potential across said first and second electrodes, in a direction having at least a component lying along a line joining said source of light with said second reflective surface;
• and
• a controllable source of potential coupled to at least said first and second electrodes of said first electrostrictive element for controllably causing striction of said first electrostrictive element for thereby controllably setting the position of said first reflective surface, said spacing of said first and second electrodes being selected in conjunction with the range of magnitude of said potential so that, at a first magnitude of said potential, said first reflective surface is at the same distance from said light source as said reference reflective surface for thereby reflecting all of said polychromatic light, and also being selected so that if said polychromatic light is white, and if said first reflective surface is caused to be displaced in the direction of said component relative to said reference reflective surface by one-quarter wavelength of red light at a second magnitude of said potential, a tendency to cause destructive interference of red light results in reflection of light of a predominantly blue-green color, if said first reflective surface is caused to be displaced in the direction of said component relative to said reference reflective surface by one-quarter wavelength of green light at a third magnitude of said potential, a tendency to cause destructive interference of green light results in reflection of a predominantly violet color, and, if said first reflective surface is caused to be displaced in said direction of said component relative to said reference reflective surface by one-quarter wavelength of blue light at a fourth magnitude of said potential, a tendency to cause destructive interference of blue light results in reflection of a predominantly yellow color.