Optical sheet for TFT-LCD back light unit and liquid crystal display having the optical sheet
The present invention relates to an optical sheet for a backlight unit of a TFT-LCD and a TFT-LCD including the same. The optical sheet of the present invention includes a transparent base sheet, and a light diffusion layer in which a diffusion pattern comprised of a plurality of protrusions is formed on the transparent base sheet. The diffusion pattern satisfies an aspect ratio of 0.8 or more, the aspect ratio being a ratio of a radius (l) of a unit body portion of the protrusion, which is formed on the transparent base sheet, to a thickness (d) of the protrusion.
1. An optical sheet for a backlight unit of a TFT-LCD, comprising:
a transparent base sheet; and
a light diffusion layer in which a diffusion pattern comprised of a plurality of protrusions is formed on the transparent base sheet,
wherein the diffusion pattern has an aspect ratio of 0.8 or more, the aspect ratio satisfies below:
a
thickness
(
d
)
of
the
protrusion
a
radius
(
1
)
of
a
unit
body
portion
of
the
protrusion
≥
0.8
.
2. The optical sheet as claimed in claim 1 , wherein the diffusion pattern has a surface shape formed by an e-beam irradiation apparatus.
3. The optical sheet as claimed in claim 2 , wherein the e-beam is irradiated to emit thermal electrons by heating a high-melting point material filament made of at least one selected from the group consisting of tungsten, tantalum and molybdenum.
4. The optical sheet as claimed in claim 2 , wherein the e-beam is irradiated within a wavelength range of 0.005 to 0.1 nm.
5. The optical sheet as claimed in claim 2 , wherein the e-beam is irradiated in an absorbed dose of 40 to 120 kGy.
6. The optical sheet as claimed in claim 1 , wherein the aspect ratio ranges from 0.8 to 1.5.
7. The optical sheet as claimed in claim 1 , wherein the plurality of protrusions has a spherical or semi-spherical shape.
8. The optical sheet as claimed in claim 1 , wherein the radius (l) of the unit body portion of the protrusion ranges from 0.005 to 50 μm.
9. The optical sheet as claimed in claim 1 , wherein the diffusion pattern is formed by applying a composition, comprised of the non-cross-linked polymer resin and cross-linked organic particles, on the transparent base sheet and has a spherical or semi-spherical shape.
10. The optical sheet as claimed in claim 9 , wherein the polymer resin comprises thermosetting resin.
11. A backlight assembly including at least one optical sheet, the optical sheet comprising:
a transparent base sheet; and
a light diffusion layer in which a diffusion pattern comprised of a plurality of protrusions is formed on the transparent base sheet,
wherein the diffusion pattern has an aspect ratio of 0.8 or more, the aspect ratio satisfies below:
a
thickness
(
d
)
of
the
protrusion
a
radius
(
1
)
of
a
unit
body
portion
of
the
protrusion
≥
0.8
.
12. The backlight assembly as claimed in claim 11 , wherein the diffusion pattern has a surface shape formed by an e-beam irradiation apparatus which emits thermal electrons by heating a high-melting point material filament made of at least one selected from the group consisting of tungsten, tantalum and molybdenum.
13. The backlight assembly as claimed in claim 12 , wherein the e-beam is irradiated within a wavelength range of 0.005 to 0.1 nm.
14. The backlight assembly as claimed in claim 12 , wherein the e-beam is irradiated in an absorbed dose of 40 to 120 kGy.
15. The backlight assembly as claimed in claim 11 , wherein the aspect ratio ranges from 0.8 to 1.5.
16. The backlight assembly as claimed in claim 11 , wherein the plurality of protrusions has a spherical or semi-spherical shape.
17. The backlight assembly as claimed in claim 11 , wherein the radius (l) of the unit body portion of the protrusion ranges from 0.005 to 50 μm.
18. The backlight assembly as claimed in claim 11 , wherein the diffusion pattern is formed by applying a composition, comprised of the non-cross-linked polymer resin and cross-linked organic particles, on the transparent base sheet and has a spherical or semi-spherical shape.
19. The backlight assembly as claimed in claim 18 , wherein the polymer resin comprises thermosetting resin.
20. A TFT-LCD, comprising:
a backlight assembly, the backlight assembly including at least one optical sheet, the optical sheet comprising:
a transparent base sheet; and
a light diffusion layer in which a diffusion pattern comprised of a plurality of protrusions is formed on the transparent base sheet,
wherein the diffusion pattern has an aspect ratio of 0.8 or more, the aspect ratio satisfies below:
a
thickness
(
d
)
of
the
protrusion
a
radius
(
1
)
of
a
unit
body
portion
of
the
protrusion
≥
0.8
.