Abstract: A surface lighting device includes a light guiding plate having a light incident surface formed at one end surface and a light exit surface formed on a front surface thereof; an elongated light source facing the light incident surface; a light source reflector which reflects light emitted from the elongated light source toward the light incident surface; a prism sheet, wherein an array of minute parallel prism projections is formed on a surface thereof, the array of minute parallel prism projections facing the light exit surface; a regular reflection type reflector facing a rear surface of the light guiding plate; a light guiding device for guiding light emitted from the elongated light source to two portions of the light incident surface which respectively face opposite ends of the elongated light source; and a diffuser, formed on the light incident surface, which diffuses incident light thereon.

Abstract: A surface lighting device including a light guiding plate (11) including two light incident surfaces (11a) formed at opposite end surfaces of the light guiding plate and a light exit surface (11b); two elongated light sources (12) that face the two light incident surfaces; and a reflector plate (14) positioned to face a rear surface of the light guiding plate, and to reflect light toward said light exit surface. The light guiding plate includes (i) alight projecting device (11d) that projects light from the light exit surface; (ii) a light quantity control device that controls a quantity of the light to be emitted, by the light projecting device, from the light exit surface; and (iii) a light condensing device (11e) that condenses the light to be emitted from the light exit surface.

Abstract: A planar light source device contains a light source (1); a light guide (2) which has a light incident face (21) on at least one side end surface thereof which confronts the light source (1), and a light emitting face (23) on one of two principal surfaces (23, 24) thereof; and a light direction varying sheet (4) which is disposed on the light emitting face (23) of the light guide (2), wherein a back surface (24) of the light guide (2) opposing to the light emitting face (21) is formed as a prism surface which comprises a plurality of elongated prisms each having substantially triangular cross section of a vertical angle within a range of 60 to 80° or 125 to 150° so as to extend in parallel to each other and in perpendicular to the light incident face (21), and a major part of the light emitting face (23) is formed as an uneven surface having an average slant angle of 0.3 to 30°.

Abstract: A planar light source device contains a light source (1); a light guide (2) which has a light incident face (21) on at least one side end surface thereof which confronts the light source (1), and a light emitting face (23) on one of two principal surfaces (23, 24) thereof; and a light direction varying sheet (4) which is disposed on the light emitting face (23) of the light guide (2), wherein a back surface (24) of the light guide (2) opposing to the light emitting face (21) is formed as a prism surface which comprises a plurality of elongated prisms each having substantially triangular cross section of a vertical angle within a range of 60 to 80° or 125 to 150° so as to extend in parallel to each other and in perpendicular to the light incident face (21), and a major part of the light emtting face (23) is formed as an uneven surface having an average slant angle of 0.3 to 30°.

Abstract: A surface lighting device includes a light guiding plate having a light incident surface formed at one end surface and a light exit surface formed on a front surface thereof; an elongated light source facing the light incident surface; a light source reflector which reflects light emitted from the elongated light source toward the light incident surface; a prism sheet, wherein an array of minute parallel prism projections is formed on a surface thereof, the array of minute parallel prism projections facing the light exit surface; a regular reflection type reflector facing a rear surface of the light guiding plate; a light guiding device for guiding light emitted from the elongated light source to two portions of the light incident surface which respectively face opposite ends of the elongated light source; and a diffuser, formed on the light incident surface, which diffuses incident light thereon.

Abstract: A surface light source device, comprising a light source (2); a light conductor (1) which has a light incident face (11) on at least one side end surface thereof which confronts the light source (2), and a light emitting face (12) on one surface thereof which is substantially perpendicular to the light incident face (11); and a light angle varying sheet (3) which is disposed at a side of the light emitting face (12) of the light conductor (1), wherein at least one of the light emitting face (12) and a back surface (13) of the light conductor (1) comprises a minute structure having an average slant angle of 0.5 to 7.5 degrees. The light angle varying sheet (3) may comprise a prism sheet having a plurality of prisms (31) which are formed parallel to one another on at least one surface thereof.

Abstract: A resin sheet having laminated transparent resin layers and a smooth outer surface, the refractive indexes of two resins of any adjacent two resin layers differing from each other, the interfaces among the resin layers having an uneven shape, is produced with an extrusion molding apparatus having such a structure that a plurality of transparent resins are extruded from respective separate flow passages into a composite resin flow passage to form a composite resin flow having a laminate structure with an uneven shape at the interfaces of the resin layers, and that the composite resin flow is extruded from an outlet of the composite resin flow passage. The resin sheet is used as a laminate, or a light guide of a surface light source element.

Abstract: A surface light source device, comprising a light source (2); a light conductor (1) which has a light incident face (11) on at least one side end surface thereof which confronts the light source (2), and a light emitting face (12) on one surface thereof which is substantially perpendicular to the light incident face (11); and a light angle varying sheet (3) which is disposed at a side of the light emitting face (12) of the light conductor (1), wherein at least one of the light emitting face (12) and a back surface (13) of the light conductor (1) comprises a minute structure having an average slant angle of 0.5 to 7.5 degrees. The light angle varying sheet (3) may comprise a prism sheet having a plurality of prisms (31) which are formed parallel to one another on at least one surface thereof.

Abstract: A surface light source device, comprising a light source (2); a light conductor (1) which has a light incident face (11) on at least one side end surface thereof which confronts the light source (2), and a light emitting face (12) on one surface thereof which is substantially perpendicular to the light incident face (11); and a light angle varying sheet (3) which is disposed at a side of the light emitting face (12) of the light conductor (1), wherein at least one of the light emitting face (12) and a back surface (13) of the light conductor (1) comprises a minute structure having an average slant angle of 0.5 to 7.5 degrees. The light angle varying sheet (3) may comprise a prism sheet having a plurality of prisms (31) which are formed parallel to one another on at least one surface thereof.

Abstract: An amorphous alloy which has a composition represented by the general formula (Fe.sub.1-a Co.sub.a).sub.1-x-y-z P.sub.x W.sub.y M.sub.z (where 0.9.ltoreq.a, 0.04.ltoreq.x.ltoreq.0.16, 0.005.ltoreq.y.ltoreq.0.05, 0.ltoreq.z.ltoreq.0.2, and M is one or more transition elements other than Fe, Co, and W. In a method for producing the amorphous alloy comprising at least Fe, Co, P and W by electrodeposition, the electrodeposition is performed in an acidic electrolyte bath which employs phosphorous acid and/or a phosphite as the P source and sodium tungstate as the W source, or in an acidic electrolyte bath which employs sodium phosphotungstate as the P and W source. The amorphous alloy which contains phosphorous as the metalloid element exhibits little reduction in saturation magnetization, and the crystallization temperature may be increased to above 450.degree. C.

Abstract: A thin amorphous alloy of cobalt, iron and phosphorus having good workability and the ability to be used as a soft magnetic material is formed by electrolytic deposition. The electrolytic bath has a pH of 1.0 to 2.2 and contains at least a divalent cobalt ion, a divalent iron ion, and phosphorous acid and/or a phosphite. The amorphous alloy contains at least 69 atomic percent cobalt, 2 to 30 atomic percent phosphorus and the iron/(cobalt+iron) atomic ratio is from 0.001 to 0.1. The alloy may be deposited on a working electrode having a chrome-plated surface with a center line average roughness of less than 1 .mu.m and may be peeled from the electrode to obtain a tape-shaped or foil-shaped product.

Abstract: A method of measuring light transmission losses of optical materials comprising projecting light beams at two separate points alternatively or a light beam through a part of an optical material to be measured, and detecting the intensities of light radiated at two separate points lying along the direction of propagation of said light beams in said part.