Light-scattering light-guiding device

A light scattering light-guiding device according to claim 1, wherein outgoing light emitted from the light exit surface is emitted at a direction of 30.degree.-40.degree. with respect to the direction light travels when received by the at least one side surface region.-

• 3. A light-scattering light-guiding device comprising:
• a plate shaped light-scattering light guide having at least one side surface region for receiving light, a light exit surface for emitting outgoing light in a first direction, and a volume region having a substantially uniform scattering power,
• said volume region having an effective scattering illumination parameter E whose value lies in a range of 0.45 cm.sup.-1 .ltoreq.E.ltoreq.100 cm.sup.-1, and a nonuniform refractive index structure for producing said scattering power, said nonuniform refractive index structure being expressed by a correlation function .gamma. (r) approximated by exp (-R/a), where r is a distance between two points in said volume region and a is a correlation distance whose value lies in a range of 0.01 .mu.m.ltoreq.a.ltoreq.50 .mu.m, and
• said nonuniform refractive index structure being particulate material uniformly dispersed in a matrix, the refractive index of said particulate material being different from the refractive index of the matrix by 0.001 or more;
• and
• a light exit direction modifying prismatic element disposed along the light exit surface for changing the direction of the emitted light from the
• first direction to a second direction. 4. A light scattering light guiding device according to claim 3, wherein the second direction is perpendicular to the light exit surface.