Abstract: Provided is a carbon fiber bundle for obtaining a fiber-reinforced plastic having high mechanical characteristics. An acrylonitrile swollen fiber for a carbon fiber having openings of 10 nm or more in width in the circumference direction of the swollen fiber at a ratio in the range of 0.3 openings/?m2 or more and 2 openings/?m2 or less on the surface of the swollen fiber, and the swollen fiber is not treated with a finishing oil agent. A precursor fiber obtained by treating the swollen fiber with a silicone-based finishing oil agent has a silicon content of 1700 ppm or more and 5000 ppm or less, and the silicon content is 50 ppm or more and 300 ppm or less after the finishing oil agent is washed away with methyl ethyl ketone by using a Soxhlet extraction apparatus for 8 hours. The fiber is preferably an acrylonitrile copolymer containing acrylonitrile in an amount of 96.0 mass % or more and 99.7 mass % or less and an unsaturated hydrocarbon having at least one carboxyl group or ester group in an amount of 0.

Abstract: A process for producing a flame-resistant fiber bundle, the process comprising a step in which a flame-resistant fiber bundle (1) having a single-fiber density ?F1 of 1.26 g/cm3 to 1.36 g/cm3 is brought into contact sequentially with a heater group having a surface temperature TH of 240° C. to 400° C. under the following conditions (A), (B), and (C) to obtain a flame-resistant fiber bundle (2) having a single-fiber density ?F2 of 1.33 g/cm3 to 1.43 g/cm3: (A) the heater Hn+1 with which the fiber bundle is brought into contact “n+1”-thly has a highter temperature than the heater Hn with which the fiber bundle is brought into contact “n”-thly; (B) the total contact time between the fiber bundle and the heater group is 10 seconds to 360 seconds; and (C) the contact time between the fiber bundle and each heater is 2 seconds to 20 seconds.

Abstract: Provided are: a carbon fiber bundle which has a large value of single-fiber fineness and excellent productivity and which, despite this, contains few interlaced single fibers therein and has excellent spreadability; and precursor fibers which are suitable for use in producing the carbon fiber bundle. The precursor fibers are a carbon-fiber-precursor acrylic fiber bundle which comprises a polyacrylonitrile copolymer comprising 95-99 mol % acrylonitrile units and 1-5 mol % hydroxyalkyl (meth)acrylate units and which has a single-fiber fineness of 1.5-5.0 dtex. In the acrylic fiber bundle, the cross-section of each single fiber which is perpendicular to the fiber axis has a shape that has a roundness of 0.9 or less.

Abstract: Provided is a carbon fiber bundle for obtaining a fiber-reinforced plastic having high mechanical characteristics. An acrylonitrile swollen fiber for a carbon fiber having openings of 10 nm or more in width in the circumference direction of the swollen fiber at a ratio in the range of 0.3 openings/?m2 or more and 2 openings/?m2 or less on the surface of the swollen fiber, and the swollen fiber is not treated with a finishing oil agent. A precursor fiber obtained by treating the swollen fiber with a silicone-based finishing oil agent has a silicon content of 1700 ppm or more and 5000 ppm or less, and the silicon content is 50 ppm or more and 300 ppm or less after the finishing oil agent is washed away with methyl ethyl ketone by using a Soxhlet extraction apparatus for 8 hours. The fiber is preferably an acrylonitrile copolymer containing acrylonitrile in an amount of 96.0 mass % or more and 99.7 mass % or less and an unsaturated hydrocarbon having at least one carboxyl group or ester group in an amount of 0.

Abstract: In a lens sheet, a lens portion (3) made of activation energy curing resin such as ultraviolet curing resin has a plurality of lens units, the lens portion (3) is disposed on at least one side of a transparent substrate (2) such as plastic sheet, a relaxation layer (1) is disposed between the transparent substrate (2) and the lens portion (3), and the thickness of the relaxation layer (1) is within a range of 1% to 30% of the height (H) of the lens units. The relaxation layer (1) is made of activation energy curing resin and formed integrally with the lens portion (3). The refractive index of the transparent substrate (2) is lower than that of the lens portion (3). The lens units are elongated prisms each having a substantially triangular cross section. The thickness of the relaxation layer is within a range of 1 ?m to 10 ?m, for example. The prisms have the vertical angle of 50° to 75° and are arranged with a pitch of 10 ?m to 150 ?m.

Abstract: In a lens sheet, a lens portion (3) made of activation energy curing resin such as ultraviolet curing resin has a plurality of lens units, the lens portion (3) is disposed on at least one side of a transparent substrate (2) such as plastic sheet, a relaxation layer (1) is disposed between the transparent substrate (2) and the lens portion (3), and the thickness of the relaxation layer (1) is within a range of 1% to 30% of the height (H) of the lens units. The relaxation layer (1) is made of activation energy curing resin and formed integrally with the lens portion (3). The refractive index of the transparent substrate (2) is lower than that of the lens portion (3). The lens units are elongated prisms each having a substantially triangular cross section. The thickness of the relaxation layer is within a range of 1 &mgr;m to 10 &mgr;m, for example. The prisms have the vertical angle of 50° to 75° and are arranged with a pitch of 10 &mgr;m to 150 &mgr;m.

Abstract: A transparent filter including a sheet-shaped body and numerous linear conductive elements arrayed on a surface thereof, which is adapted to be disposed in front of an image device having rectangular pixels; wherein the conductive elements with a linewidth of 50 &mgr;m or less are arrayed on the sheet-shaped body in two directions with a pitch P1 and a pitch P2, respectively; an aperture ratio of the filter is not less than 70%; and when lengths of a pixel of the image device in the vertical direction Y and in the horizontal direction X are denoted by W1 and W2, respectively, P1, P2, W1 and W2 satisfy a relation expressed by the following Equation (1) and Equation (2), n1+0.35≦W1/P1≦n1+0.65  (1) n2+0.35≦W2/P2≦n2+0.65  (2) The use of the transparent filter can increase the aperture ratio in comparison with that of a conventional mesh, and besides the disposal thereof in front of an image device having rectangular pixels can make the moire inconspicuous.

Abstract: In a lens sheet, a lens portion made if activation energy curing resin such as ultraviolet curing resin has a plurality of lens units, the lens portion is disposed on at least one side of a transparent substrate such as plastic sheet, a relaxation layer is disposed between the transparent substrate and the lens portion, and the thickness of the relaxation layer is within a range of 1% to 30% of the height of the lens units. The relaxation layer is made of activation energy curing resin and formed integrally with the lens portion. The refractive index of the transparent substrate is lower than that of the lens portion. The lens units are elongated prisms each having a substantially triangular cross section.