Optical sheet and display device having the same

1. An optical sheet comprising:

a first plane;

a second plane opposite to the first plane; and

a plurality of optical patterns formed on the second plane along a plurality of columns, the optical patterns including a plurality of convex light-condensing portions connected to each other and forming crests and troughs,

wherein troughs in a first optical pattern have a height different from a height of troughs disposed between the first optical pattern, and a second optical pattern adjacent to the first optical pattern, the heights taken with respect to the second plane.

2. The optical sheet of claim 1 , wherein optical patterns disposed in odd-numbered columns are arranged alternatively with optical patterns disposed in even-numbered columns.

3. The optical sheet of claim 2 , wherein the troughs of the optical patterns disposed in the odd-numbered columns include a first height with respect to the second plane, and

the troughs of the optical patterns disposed in the even-numbered columns have a second height with respect to the second plane, the second height being greater than the first height.

4. The optical sheet of claim 3 , wherein the optical patterns disposed in the odd-numbered columns share common sides with the optical patterns disposed in the even-numbered columns.

5. The optical sheet of claim 2 , wherein the troughs of the optical patterns disposed in the odd-numbered column have substantially same height with respect to the second plane as the troughs of the optical patterns disposed in the even-numbered columns.

6. The optical sheet of claim 2 , wherein the optical patterns disposed in adjacent columns share common sides forming a zigzag shape along a longitudinal direction of the columns.

7. The optical sheet of claim 2 , wherein the common side of the optical patterns in the adjacent columns form a wave shape along a longitudinal direction of the columns.

8. The optical sheet of claim 2 , wherein a width of a cross-section of the light condensing portion in odd-numbered columns is greater than a width of a cross section of the light condensing portion in even-numbered columns.

9. An optical sheet comprising:

a first plane;

a second plane opposite to the first plane; and

a plurality of optical patterns disposed on the second plane along a plurality of columns, the optical patterns including a plurality of convex light-condensing portions connected to each other and forming crests and troughs, wherein the convex light-condensing portion comprises:

two first ridges between adjacent troughs and adjacent crests along a longitudinal direction of the columns; and

two second ridges between each of the troughs and adjacent crests along a horizontal direction substantially in perpendicular to the longitudinal direction.

10. The optical sheet of claim 9 , wherein the first ridges disposed in each of the odd-numbered columns form a first vertex angle and the first ridges disposed in each of the even-numbered columns form a second vertex angle, and

wherein each of the first vertex angle and the second vertex angle is between about 85 degrees and about 95 degrees.

11. The optical sheet of claim 9 , wherein vertexes of the light condensing portions in the odd-numbered columns and even-numbered columns are rounded.

12. The optical sheet of claim 9 , wherein the second ridges are connected to the troughs of the adjacent columns.

13. The optical sheet of claim 9 , wherein the first ridges disposed in each of the odd-numbered columns form a first vertex angle, and

the first ridges disposed in each of the even-numbered columns form a second vertex angle that is greater than the first vertex angle.

14. An optical sheet comprising:

a first plane;

a second plane opposite to the first plane; and

a plurality of optical patterns formed on the second plane along a plurality of columns. the optical patterns including a plurality of convex light-condensing portions connected to each other and forming crests and troughs,

wherein a cross-section of the light-condensing portion taken along a horizontal direction substantially in perpendicular to a longitudinal direction of the columns has a rugby football shape.

15. A display device comprises:

a backlight assembly emitting light;

an optical sheet including;

a first plane;

a second plane opposite to the first plane; and

a plurality of optical patterns formed on the second plane along a plurality of columns, the optical patterns including a plurality of convex light-condensing portions connected to each other and forming crests and troughs,

wherein troughs in a first optical pattern have a height different from a height of troughs disposed between the first optical pattern, and a second optical pattern adjacent to the first optical pattern, the heights taken with respect to the second plane; and

a display panel disposed on the optical sheet to display images based on light emitting from the optical sheet.

16. The display device of claim 15 , wherein the backlight assembly comprises:

a light source disposed under the optical sheet and generating the light; and

a diffusion plate disposed between the light source and the optical sheet diffusing the light.

17. The display device of claim 15 , further comprising a diffusing sheet disposed between the diffusion plate and the optical sheet.

18. The display device of claim 15 , wherein the backlight assembly comprises:

a light source generating the light; and

a light guide unit guiding the light incident into the light guide unit through a side surface of the light guide unit to emit the light to the optical sheet.

19. The display device of claim 15 , further comprising a protective sheet disposed on the optical sheet to protect the optical patterns.