Abstract: A surface light source device of side light type includes a primary light source, a reflection sheet, a light scattering guide plate, and a prism sheet. The primary light source comprises a fluorescent lamp and a reflector to supply illumination light toward an incidence surface of the light scattering guide plate. The light scattering guide plate has an emission surface and a back surface, with the prism sheet being disposed along the emission surface. On the emission surface and/or the back surface, a great number of grooves running generally perpendicular to the incidence surface within a range of distance W1 and/or W2 from an upper edge EU and/or a lower edge EL. These grooves provide a corrugate shape in a cross section parallel to the incidence surface. Depth of corrugate shape gradually becomes shallower as getting away from the incidence surface.

Abstract: A wedge-shaped light scattering guide plate 10 employed in a surface light source device of side-light type has a width equal to the length of a primary light source element. An incidence end surface 11 is formed as a matte surface (rough surface) by a matting process. The incidence end surface 11 is provided with roughness which is uniform or increases toward end portions. The roughened incidence end surface 11 produces scattered light in the vicinity of the incidence end surface, especially at both side end portions. The scattered light contributes to elimination of variation in luminance which tends to occur in the vicinity of the incidence end surface 11. A light diffusing plate may be interposed between the primary light source element and the light scattering guide plate.

Abstract: A graded-refractive-index optical plastic material composed of an amorphous fluoropolymer (a) which has substantially no C--H bond and at least one material (b) which has substantially no C--H bond and differs from the fluoropolymer (a) in refractive index by at least 0.001, wherein the material (b) is distributed in the fluoropolymer (a) so as to have a concentration gradient in a specific direction, and the optical plastic material has a glass transition temperature which is substantially uniform throughout it.

Abstract: A light incident into a wedge type light scattering conducting element from a light incident surface of the light scattering conducting element is converted into a light flux having a directionality and is output from a light output surface. The output light is input to a wedge type emitting direction characteristic adjusting element arranged with a positional relationship complementary to the light scattering conducting element. A prism shaped irregularity for adjusting a propagating directionality of the light in longitudinal/transverse directions is formed on a light input surface/light output surface of the wedge type emitting direction characteristic adjusting element. The wedge type emitting direction characteristic adjusting element has a weakened scattering power depending on requirements, thereby a degree of directionality sharpness of the light emitted from a surface light source device is adjusted.

Abstract: There is provided a surface light source device which is excellent in whiteness and softness of a luminant surface and able to retain reflective appearance from occurring. The surface light source device is effectively applied to back lighting in a liquid crystal display. A fluorescent lamp (L) is disposed in the vicinity of an incidence surface (2) of a light guide plate (1). A prism sheet (4') having prism surfaces formed on both surfaces is disposed along an exiting surface (5). The prism sheet (4') is oriented such that prism rows (4a, 4b) on the inside surface run in the transverse direction of the light guide plate (1) while prism rows (4c, 4d) on the outside surface run in the longitudinal direction of the light guide plate (1). A reflector (3) is disposed along a back surface (6) of the light guide plate (1).

Abstract: A surface light source device of side light type controls the intensity of light rays emitted therefrom. The surface light source device of side light type comprises a light scattering guide 20 having a light incidence surface 22, a light emission surface 23 and an inclined surface 25. The device further includes a primary light source L arranged around one side of the light incidence surface 22, a silver foil R surrounding the primary light source L, a prism sheet 4 arranged along the light emission surface 23, and a silver foil S arranged along the inclined surface 25. The inclined surface 25 of the light scattering guide 20 composed of three sections I, II and III. The section I is a convex cylindrical surface section having a radius of curvature of 330 mm. The tangential direction at the end of the guide on the side of the light incidence surface 22 is parallel to the light emission surface 23. The tangential direction at the boundary between the sections I and II is inclined at an angle 4.degree.

Abstract: In a surface light source device of side light type, occurrence of irregularities in luminance is prevented in the vicinity of an incidence surface 10 of a light guide plate 1. A light source element 2 is disposed on a lateral side of the light guide plate 1 and the light introduced into the light guide plate 1 through the incidence surface 10 is emitted through an emission surface 11. The light comes outside after undergoing the action of an additional element 3 (such as a priority traveling direction correcting action) and is applied to, for example, back lighting in a liquid crystal display. A reflection sheet such as a silver foil is disposed along a rear surface 12. The rear surface 12 is treated in various manners in order to reflect the light toward the emission surface 11. Another reflection sheet 20 is disposed as a reflector surrounding the light source element 2 from the back side. A case 4 partially projects inward along the incidence surface 10 to form light shielding walls 8, 9.

Abstract: A graded-refractive-index optical plastic material composed of an amorphous fluoropolymer and at least one material which differs from the polymer in refractive index by at least 0.001, wherein the material is so distributed as to have a concentration gradient in a specific direction, and a method for its production.

Abstract: A graded-refractive-index optical plastic material composed of an amorphous fluoropolymer (a) which substantially has no C-H bond and at least one material (b) which differs from the fluoropolymer (a) in refractive index by at least 0.001, wherein the material (b) is distributed in the fluoropolymer (a) so as to have a concentration gradient in a specific direction.

Abstract: A method of manufacturing a multimode optical transmission medium from a synthetic resin having the distribution of refractive index varying continuously in a fixed direction. In the method, a monomer is polymerized while a transparent polymer for constituting the wall of a vessel is being dissolved into the monomer. Therefore, this method is free from the defect of methods using conventional polymerization reactions, and has an extremely high productivity.

Abstract: A method of manufacturing a multimode optical transmission medium from a synthetic resin having the distribution of refractive index varying continuously in a fixed direction. In the method, the polymerization is caused to proceed utilizing the effect of diffusion or exclusion of a monomer in the gel formed at the polymerization initiating terminal. Therefore, this method is free from the defects of methods using conventional polymerization reactions, and has an extremely high productivity.