Patent ID: 7527829

Claim:
Fluid colloidal crystals comprising a solid-liquid colloidal dispersion containing monodisperse spherical colloidal particles as a dispersoid, wherein: the spherical colloidal particles are organic or inorganic polymer monodisperse dispersoid spherical colloidal particles having a mean volume diameter (d) of not more than 30 μm and having one achromatic color selected from grayish white, gray, grayish black and black which have been colored with a dye or a pigment, the solid-liquid colloidal dispersion comprises the dispersoid having a dispersion concentration, as expressed on the volume basis, of not less than 20% and not more than 70% and an aqueous solution or a water-containing non-aqueous solution as a dispersion medium, around the dispersoid spherical colloidal particles in the solid-liquid colloidal dispersion having an electrostatic charging degree of not more than 2000 μS/cm in terms of an electrical conductivity, an electric double layer of a given thickness (Δe) is formed at a temperature of not lower than a freezing point of the dispersion medium solution, and the dispersoid spherical colloidal particles form a three-dimensionally ordered lattice that shows fluidity and is a particle array structure in which the spherical colloidal particles are longitudinally and laterally aligned in a lattice form while an interparticle distance (L) defined as a distance between centers of the particles arranged opposite to each other along the center line satisfies the relationship (d)<(L)≦(d)+2(Δe).