Optical sheet having bonded prism and polarizer sheets and display device

1. An optical sheet comprising:

a first lens sheet having a plurality of first three-dimensional structures arrayed to extend along a first direction on a light-emitting surface thereof;

a reflective polarizer sheet for transmitting either one of p-polarization component and s-polarization component of incident light and reflecting the other of p-polarization component and s-polarization component of the incident light,

a bonding layer;

a second lens sheet having a plurality of second three-dimensional structures arrayed to extend along a second direction on a first surface thereof, the second direction intersecting with the first direction of the first three-dimensional structure;

wherein head portions of the first three-dimensional structures are bonded to the reflective polarizer sheet through the bonding layer;

each of the first three-dimensional structures arrayed in the first direction has a width of not less than 110 μm and not more that 330 μm;

each of the first three-dimensional structures arrayed in the first direction has a bonding width of not more that 20% of the width of the arrayed direction of the first three-dimensional structures; and

wherein a second surface of the second lens sheet is bonded to the reflective polarizer sheet on a surface of the reflective polarizer that is opposite to the surface of the reflective polarizer to which the first lens sheet is bonded.

2. The optical sheet as claimed in claim 1 , wherein each of the first three-dimensional structures has a prismatic geometry, and a hyperbolic or a spherical curved surface in an array direction.

3. The optical sheet as claimed in claim 1 , wherein each of the first three-dimensional structures has a plurality of convex portions in the extended or arrayed direction.

4. The optical sheet as claimed in claim 1 , wherein the reflective polarizer sheet has a stacked structure in which a multi-layered film having different refractive indices between adjacent films each other is held between diffuser films.

5. The optical sheet as claimed in claim 1 , further comprising a diffuser film having a haze value due to forward scattering which is larger than a haze value due to back scattering.

6. The optical sheet as claimed in claim 1 , wherein each of the second three-dimensional structures has a hyperbolic or aspherical curved surface in the arrayed direction.

7. The optical sheet as claimed in claim 1 , wherein each of the second three-dimensional structures has a width of not more than 50 μm.

8. A display device comprising:

a panel driven based on image signals;

a light source emitting light for illuminating the panel;

an optical sheet provided between the panel and the light source;

wherein the optical sheet has a lens sheet having a plurality of first three-dimensional structures arrayed to extend along a first direction on a light emitting surface thereof, a bonding layer, and a reflective polarizer sheet for transmitting either one of p-polarization component and s-polarization component of incident light and reflecting the other of p-polarization component and s-polarization component of the incident light, head portions of the three-dimensional structures being bonded to the reflective polarizer sheet through the bonding layer;

a second lens sheet having a plurality of second three-dimensional structures arrayed to extend along a second direction on a first surface thereof, the second direction intersecting with the first direction of the first three-dimensional structure;

each of the first three-dimensional structures arrayed in the first direction has a width of not less than 110 μm and not more that 330 μm;

each of the first three-dimensional structures arrayed in the first direction has a bonding width of not more that 20% of the width of the arrayed direction of the first three-dimensional structures; and

wherein a second surface of the second lens sheet is bonded to the reflective polarizer sheet on a surface of the reflective polarizer that is opposite to the surface of the reflective polarizer to which the optical sheet is bonded.

9. The optical sheet as claimed in claim 1 , wherein the first three-dimensional structures and the second three-dimensional structures extend in a same direction away from the surfaces of the first lens sheet and the second lens sheet respectively.

10. The display device as claimed in claim 8 , wherein the first three-dimensional structures and the second three-dimensional structures extend in a same direction away from the surfaces of the optical sheet and the second lens sheet respectively.