Diffusion plate and display apparatus having the same

1. A display apparatus comprising:

a display panel;

a plurality of light sources provided below the display panel to emit light; and

a diffusion plate provided between the display panel and the light sources to diffuse the light, the diffusion plate comprising a base having a front surface and a rear surface, and a plurality of convex portions on the front surface of the base,

wherein a sectional surface of each convex portion is a crescent of an ellipse,

wherein the sectional surface is perpendicular to the front surface,

a ratio of a major axis to a minor axis of the ellipse is from about 2.6 to about 3.3,

a ratio of a distance between two adjacent sources and a distance between one of the light sources and the diffusion plate is about 2.0 and more, and

when a length from the front surface of the base to a vertex of each convex portion is h and a length of the chord of the ellipse is p, equation

h

=

1

2

⁢

p

×

tan

⁢

⁢

θ

is satisfied, wherein θ is about 41° to about 45° .

2. The display apparatus of claim 1 , wherein the convex portion are integrally formed with the base while extending in one direction.

3. The display apparatus of claim 1 , wherein the chord has a length of about 50 μm to about 300 μm.

4. The display apparatus of claim 1 , wherein the diffusion plate comprises a material selected from the group of consisting of polycarbonate, polystyrene, polymethylmethacrylate, and methacrylate styrene.

5. The display apparatus of claim 1 , wherein the display panel has a rectangular shape, a diagonal line of the display panel has a length of about 32 inches, and eight cold cathode fluorescent lamps are used as the light sources.

6. The display apparatus of claim 5 , wherein a distance between two adjacent light sources is about 40 mm to about 50 mm.

7. The display apparatus of claim 5 , wherein the distance between one of the light sources and the diffusion plate is about 17 mm to about 20 mm.

8. The display apparatus of claim 1 , further comprising a reflective plate under the light sources to reflect the light from the light sources toward the display panel.

9. The display apparatus of claim 8 , wherein a distance between one of the light sources and the reflective plate is about 4 mm to about 5 mm.

10. The display apparatus of claim 1 , further comprising a plurality of diffusion sheets provided between the display panel and the diffusion plate.

11. The display apparatus of claim 1 , wherein each light source is one of a cold cathode fluorescent lamp, an external electrode fluorescent lamp, a hot cathode fluorescent lamp and a light emitting diode.

12. A diffusion plate comprising:

a base comprising a front surface and a rear surface opposite to the front surface; and

a plurality of convex portions formed on the front surface of the base,

wherein a sectional surface of each convex portion is a crescent of an ellipse,

wherein the sectional surface is perpendicular to the front surface,

a ratio of a major axis to a minor axis of the ellipse is from about 2.6 to about 3.3, and

when a length from the front surface of the base to a vertex of each convex portion is h, and a length of the chord of the ellipse is p, equation

h

=

1

2

⁢

p

×

tan

⁢

⁢

θ

is satisfied, wherein θ is about 41° to about 45°.

13. The diffusion plate of claim 12 , wherein the convex portions are integrally formed with the base while extending in one direction.

14. The diffusion plate of claim 12 , wherein the chord has a length of about 50 μm to about 300 μm.

15. The diffusion plate of claim 12 , wherein the diffusion plate comprises a material selected from the group of consisting of polycarbonate, polystyrene, polymethylmethacrylate, and methacrylate styrene.