Laminated film
A width-direction multilayer laminated film having a large area and uniform optical properties is provided. A light guide, a light diffusion film, a light collecting film, a viewing angle control film, and an optical waveguide film, which are low cost and have excellent optical properties, as well as an illuminating device, a communication device, and a display using these films. The laminated film may include at least a structure in which a layer made of resin A (layer A) and a layer made of resin B (layer B) are alternately laminated in the width direction, wherein the width of the film is 400 mm or more and the number of layer Bs, each having a cross-sectional width from 0.1 μm to 10,000 μm, is 10 or larger.
1. A laminated film comprising a layer A made of resin A and a layer B made of resin B that are alternately laminated in the width direction, wherein the width of said film is 400 mm or more and the number of layer Bs, each having a cross sectional width from 0.1 μm to 10,000 μm, is 10 or more, wherein a distance P between adjacent layer Bs is 0.90 times to 1.10 times as large as a distance Pc between adjacent layer Bs at the center in the width direction, adjacent layer Bs exist continuously in a width direction for 300 mm or more, and the shape of said layer B is asymmetric relative to the center axis of said layer B in the thickness direction in the film thickness direction—width direction cross-section, and S 1 is not more than 0.8 times as large as S 2 , and wherein said S 1 and said S 2 are cross-sectional areas of said layer B halved by the center axis in the thickness direction and S 1 <S 2 , wherein said laminated film is used as a light diffusion film, a light collecting film, or a viewing angle control film.
2. The laminated film according to claim 1 , wherein a cross-sectional area A of said layer Bs is 0.90 times to 1.10 times as large as a cross-sectional area Ac of said layer B, said cross-sectional area Ac being located at the center in the film width direction.
3. The laminated film according to claim 1 , wherein resin B is a thermoplastic resin and more than half of said layer Bs are covered with resin.
4. The laminated film according to claim 1 , wherein one of said resins A and B is soluble to a solvent to which the other is insoluble.
5. The laminated film according to claim 1 , wherein the cross-sectional width of more than half of said layer Bs is in a range of an average cross sectional width of ±10 μm.
6. A film roll made of the laminated film according to claim 1 .
7. The film roll according to claim 6 , wherein the winding hardness variation in the width direction is from 0.0001 to 6.
8. A display using the film according to claim 1 .