Optical film, lighting device and display unit

1. A lighting device comprising:

a plurality of point light sources arranged in plane with each other; and

an optical sheet arranged in a region facing the plurality of point light sources,

wherein the plurality of point light sources are arranged in a first direction and also in a second direction intersecting with the first direction, and

the optical sheet has a tridimensional configuration that includes a first ridgeline extending in a third direction intersecting with the first and second directions, and a second ridgeline extending in a direction intersecting with the first, second and third directions, wherein

the optical sheet includes a pair of first slant faces opposed each other with the first ridgeline in between and a pair of second slant faces opposed each other with the second ridgeline in between, and

inclinations of the respective first and second slant faces are determined so that an arm length D of each X-shaped light source image, which is obtained by dividing a light source image produced from a light emitted from each of the plurality of point light sources into plural images through the optical sheet, satisfies the following expression when a pitch of the point light sources is defined as P:

D≧P/ 2.

2. A lighting device comprising:

a plurality of point light sources arranged in plane with each other; and

an optical sheet arranged in a region facing the plurality of point light sources,

wherein the plurality of point light sources are arranged in a first direction and also in a second direction intersecting with the first direction, and

the optical sheet has a tridimensional configuration that includes a first ridgeline extending in a third direction intersecting with the first and second directions, and a second ridgeline extending in a direction intersecting with the first, second and third directions; and

wherein extending directions of the first and second ridgelines are respectively determined so that a plurality of X-shaped light source images do not overlap each other.

3. A lighting device comprising:

a plurality of point light sources arranged in plane with each other; and

an optical sheet arranged in a region facing the plurality of point light sources,

wherein the plurality of point light sources are arranged in a first direction and also in a second direction intersecting with the first direction, and

the optical sheet has a tridimensional configuration that includes a first ridgeline extending in a third direction intersecting with the first and second directions, and a second ridgeline extending in a direction intersecting with the first, second and third directions; and

wherein the extending directions of the first and second ridgelines are respectively determined so that a width of space between a plurality of respective X-shaped light source images are approximately same.

4. A lighting device comprising:

a plurality of point light sources arranged in plane with each other; and

an optical sheet arranged in a region facing the plurality of point light sources, wherein the plurality of point light sources are arranged in a first direction and also in a second direction intersecting with the first direction, and

the optical sheet has a tridimensional configuration that includes a first ridgeline extending in a third direction intersecting with the first and second directions, and a second ridgeline extending in a direction intersecting with the first, second and third directions; and wherein the first direction and the second direction are orthogonal or approximately orthogonal to each other, and an angle of the first ridgeline and the first direction, which is defined as θ 1 , and

an angle of the second ridgeline and the second direction. which is defined as θ 2 , satisfy the following expressions:

10°<θ1<40°

10°<θ2<40°.

5. A lighting device comprising:

a plurality of point light sources arranged in plane with each other; and

an optical sheet arranged in a region facing the plurality of point light sources,

wherein the plurality of point light sources are arranged in a first direction and also in a second direction intersecting with the first direction, and

the optical sheet has a tridimensional configuration that includes a first ridgeline extending in a third direction intersecting with the first and second directions, and a second ridgeline extending in a direction intersecting with the first, second and third directions; and

wherein the first direction and the second direction are orthogonal or approximately orthogonal to each other, and

the angle θ 1 of the first ridgeline and the first direction and the angle θ 2 of the second ridgeline and the second direction satisfy the following expression:

θ1=θ2=25°.

6. A display unit comprising:

a panel driven based on an image signal;

a plurality of point light sources arranged in a region facing the panel; and

an optical sheet arranged between the panel and the plurality of point light sources,

wherein the plurality of point light sources are arranged in a first direction and also in a second direction intersecting with the first direction, and

the optical sheet has a tridimensional configuration that includes a first ridgeline extending in a third direction intersecting with the first and second directions, and a second ridgeline extending in a direction intersecting with the first, second and third directions; and

wherein extending directions of the first and second ridgelines are respectively determined so that a plurality of X-shaped light source images do not overlap each other.

7. An optical film having a rectangular shape, and including a first side extending in one direction and a second side extending in a direction orthogonal to the one direction,

wherein the optical film has a tridimensional configuration that includes a first ridgeline extending in a direction that intersects with extending directions of the first and second sides, respectively, and a second ridgeline extending in a direction that intersects with the extending directions of the first and second sides and extending direction of the first ridgeline; and

wherein extending directions of the first and second ridgelines are respectively determined so that a plurality of X-shaped light source images do not overlap each other.

8. A display unit comprising:

a panel driven based on an image signal;

a plurality of point light sources arranged in a region facing the panel; and

an optical sheet arranged between the panel and the plurality of point light sources,

wherein the plurality of point light sources are arranged in a first direction and also in a second direction intersecting with the first direction, and

the optical sheet has a tridimensional configuration that includes a first ridgeline extending in a third direction intersecting with the first and second directions, and a second ridgeline extending in a direction intersecting with the first, second and third directions; and

wherein the extending directions of the first and second ridgelines are respectively determined so that a width of space between a plurality of respective X-shaped light source images are approximately same.

9. A display unit comprising:

a panel driven based on an image signal;

a plurality of point light sources arranged in a region facing the panel; and

an optical sheet arranged between the panel and the plurality of point light sources,

wherein the plurality of point light sources are arranged in a first direction and also in a second direction intersecting with the first direction, and

the optical sheet has a tridimensional configuration that includes a first ridgeline extending in a third direction intersecting with the first and second directions, and a second ridgeline extending in a direction intersecting with the first, second and third directions; and

wherein the first direction and the second direction are orthogonal or approximately orthogonal to each other, and an angle of the first ridgeline and the first direction, which is defined as θ 1 , and

an angle of the second ridgeline and the second direction, which is defined as θ 2 , satisfy the following expressions:

10°<θ1<40°

10°<θ2<40°.

10. A display unit comprising:

a panel driven based on an image signal;

a plurality of point light sources arranged in a region facing the panel; and

an optical sheet arranged between the panel and the plurality of point light sources,

wherein the plurality of point light sources are arranged in a first direction and also in a second direction intersecting with the first direction, and

the optical sheet has a tridimensional configuration that includes a first ridgeline extending in a third direction intersecting with the first and second directions, and a second ridgeline extending in a direction intersecting with the first, second and third directions; and

wherein the first direction and the second direction are orthogonal or approximately orthogonal to each other, and

the angle θ 1 of the first ridgeline and the first direction and the angle θ 2 of the second ridgeline and the second direction satisfy the following expression:

θ 1 =θ 2 = 25 °.

11. An optical film having a rectangular shape, and including a first side extending in one direction and a second side extending in a direction orthogonal to the one direction,

wherein the optical film has a tridimensional configuration that includes a first ridgeline extending in a direction that intersects with extending directions of the first and second sides, respectively, and a second ridgeline extending in a direction that intersects with the extending directions of the first and second sides and extending direction of the first ridgeline; and

wherein the extending directions of the first and second ridgelines are respectively determined so that a width of space between a plurality of respective X-shaped light source images are approximately same.

12. An optical film having a rectangular shape, and including a first side extending in one direction and a second side extending in a direction orthogonal to the one direction,

wherein the optical film has a tridimensional configuration that includes a first ridgeline extending in a direction that intersects with extending directions of the first and second sides, respectively, and a second ridgeline extending in a direction that intersects with the extending directions of the first and second sides and extending direction of the first ridgeline; and

wherein the first direction and the second direction are orthogonal or approximately orthogonal to each other, and an angle of the first ridgeline and the first direction, which is defined as θ 1 , and

an angle of the second ridgeline and the second direction, which is defined as θ 2 , satisfy the following expressions:

10°<θ1<40°

10°<θ2<40°.

13. An optical film having a rectangular shape, and including a first side extending in one direction and a second side extending in a direction orthogonal to the one direction,

wherein the optical film has a tridimensional configuration that includes a first ridgeline extending in a direction that intersects with extending directions of the first and second sides, respectively, and a second ridgeline extending in a direction that intersects with the extending directions of the first and second sides and extending direction of the first ridgeline;

wherein the first direction and the second direction are orthogonal or approximately orthogonal to each other, and

the angle θ 1 of the first ridgeline and the first direction and the angle θ 2 of the second ridgeline and the second direction satisfy the following expression:

θ 1 =θ 2 = 25 °.