U.S. patent number RE45,749 [Application Number 13/423,066] was granted by the patent office on 2015-10-13 for optical unit, backlight assembly having the same and display device having the same.
This patent grant is currently assigned to SAMSUNG DISPLAY CO., LTD.. The grantee listed for this patent is In-Sun Hwang, Seong-Yong Hwang, Joong-Hyun Kim, Sang-Yu Lee, Hye-Eun Park. Invention is credited to In-Sun Hwang, Seong-Yong Hwang, Joong-Hyun Kim, Sang-Yu Lee, Hye-Eun Park.
United States Patent |
RE45,749 |
Hwang , et al. |
October 13, 2015 |
Optical unit, backlight assembly having the same and display device
having the same
Abstract
An optical unit includes a base, a light-condensing member
disposed on the base to condense a first portion of light that is
incident onto the base and protrusion members disposed on a surface
of the light-condensing member to scatter a second portion of the
light that is incident onto the base. A backlight assembly includes
light sources, an optical unit receiving light from the light
sources to condense and scatter the light, and may also include an
optical member disposed over the optical unit to enhance the front
luminance of the light. A display device includes light sources, an
optical module and a display panel. Thus, display quality of the
display device may be enhanced.
Inventors: |
Hwang; Seong-Yong (Yongin-si,
KR), Hwang; In-Sun (Suwon-si, KR), Kim;
Joong-Hyun (Suwon-si, KR), Park; Hye-Eun
(Suwon-si, KR), Lee; Sang-Yu (Yongin-si,
KR) |
Applicant: |
Name |
City |
State |
Country |
Type |
Hwang; Seong-Yong
Hwang; In-Sun
Kim; Joong-Hyun
Park; Hye-Eun
Lee; Sang-Yu |
Yongin-si
Suwon-si
Suwon-si
Suwon-si
Yongin-si |
N/A
N/A
N/A
N/A
N/A |
KR
KR
KR
KR
KR |
|
|
Assignee: |
SAMSUNG DISPLAY CO., LTD.
(KR)
|
Family
ID: |
37186573 |
Appl.
No.: |
13/423,066 |
Filed: |
March 16, 2012 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
Issue Date |
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11393281 |
Mar 29, 2006 |
7438459 |
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Reissue of: |
12235989 |
Sep 23, 2008 |
7677784 |
Mar 16, 2010 |
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Foreign Application Priority Data
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Apr 26, 2005 [KR] |
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2005-34605 |
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
G02B
3/005 (20130101); G02B 5/0231 (20130101); G02B
5/021 (20130101); G02B 27/095 (20130101); G02B
5/045 (20130101) |
Current International
Class: |
F21V
7/04 (20060101); G02B 5/02 (20060101); G02F
1/13357 (20060101); G09F 13/04 (20060101); G02B
5/04 (20060101) |
Field of
Search: |
;349/64
;362/97.1,613,617,619,97.2,620 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
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2004-006256 |
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Jan 2004 |
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JP |
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10-2002-0061802 |
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Jul 2002 |
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KR |
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10-2004-0041485 |
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May 2004 |
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KR |
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10-2004-0062286 |
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Jul 2004 |
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KR |
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10-2005-0014483 |
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Feb 2005 |
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KR |
|
Primary Examiner: Menefee; James
Attorney, Agent or Firm: Innovation Counsel LLP
Parent Case Text
CROSS REFERENCE TO RELATED APPLICATIONS
This application is a .Iadd.reissue application from U.S. patent
application Ser. No. 12/235,989 filed on Sep. 23, 2008 and issued
as U.S. Pat. No. 7,677,784, which is a .Iaddend.continuation of
U.S. patent application Ser. No. 11/393,281, filed Mar. 29, 2006,
now U.S. Pat. No. 7,438,459 which claims priority of Korean Patent
Application No. .[.2005-34605.]. .Iadd.10-2005-0034605
.Iaddend.filed on Apr. 26, 2005, the contents of which are herein
incorporated by reference in their entirety.
Claims
What is claimed is:
1. An optical unit comprising: a base; a light-condensing member
comprising a first curved slant face protruding from the base and a
second curved slant face protruding from the base, the second
curved slant face being .[.slated.]. .Iadd.slanted .Iaddend.toward
the first curved slant face; and a plurality of protrusion members
protruding from a surface of the light-condensing member .Iadd.such
that adjacent protrusion members are spaced apart from each other
to only partially cover the surface of the light-condensing
member.Iaddend..
2. The optical unit of claim 1, wherein at least one of the first
and second curved slant faces is .[.concave.].
.Iadd.convex.Iaddend..
3. The optical unit of claim 2, wherein the first and second curved
slant faces are connected at a rounded top portion.
4. The optical unit of claim 1, wherein the first curved slant face
comprises a first face protruding from the base to form a first
angle with respect to the base and a second face extending from an
upper portion of the first face to form a second angle with respect
to the base, and the second curved slant face comprises a third
face protruding from the base toward the first face to form the
first angle with respect to the base and a fourth face extending
from an upper portion of the third face to be connected to the
second face, the fourth face forming the second angle with respect
to the base.
5. The optical unit of claim 4, wherein the first angle is
.[.lager.]. .Iadd.larger .Iaddend.than the second angle.
6. The optical unit of claim 4, wherein the first and second faces
are connected at a first rounded portion, and the third and fourth
faces are connected at a second rounded portion.
7. The optical unit of claim 6, wherein the first, second, third,
and fourth faces respectively comprises a flat surface.
8. A backlight assembly comprising: a plurality of light sources
configured to generate light; .Iadd.and .Iaddend. an optical unit
to condense and diffuse the light, the optical unit comprising: a
base; a light-condens1ing portion comprising a first curved slant
face protruding from the base and a second curved slant face
protruding from the base, the second curved slant face being
.[.slated.]. .Iadd.slanted .Iaddend.toward the first curved slant
face; and a .Iadd.plurality of .Iaddend.protrusion .[.portion.].
.Iadd.portions .Iaddend.disposed on a surface of the
light-condensing portion .Iadd.such that adjacent protrusion
portions are spaced apart from each other to only partially cover
the surface of the light-condensing portion.Iaddend..
9. The backlight assembly of claim 8, wherein the light sources
have a first number and the optical unit receives the light from
the light sources to form images of the light sources, the images
having a second number that is greater than the first number.
10. The backlight assembly of claim 9, wherein the light-condensing
portion is elongated along a longitudinal direction of the light
source.
11. The backlight assembly of claim 9, wherein the first and second
curved slant faces are connected at a rounded top portion.
12. The backlight assembly of claim 11, wherein the first curved
slant face comprises a first face protruding from the base to form
a first angle with respect to the base and a second face extending
from an upper portion of the first face to form a second angle with
respect to the base, and the second curved slant face comprises a
third face protruding from the base toward the first face to form
the first angle with respect to the base and a fourth face
extending from an upper portion of the third face to be connected
to the second face, the fourth face forming the second angle with
respect to the base, wherein the first angle is larger than the
second angle.
13. The backlight assembly of claim 12, wherein the first and
second faces are connected at a first rounded portion, and the
third and fourth faces are connected at a second rounded
portion.
14. A display device comprising: a plurality of light sources to
generate light; an optical module to condense and diffuse the
light, the optical module comprising an optical unit including: a
base; a light-condensing member comprising a first curved slant
face protruding from the base and a second curved slant face
protruding from the base, the second curved slant face being
.[.slated.]. .Iadd.slanted .Iaddend.toward the first curved slant
face; and a .Iadd.plurality of .Iaddend.protrusion .[.portion.].
.Iadd.portions .Iaddend.disposed on a surface of the
light-condensing portion.[.,.]. .Iadd.such that adjacent protrusion
portions are spaced apart from each other to only partially cover
the surface of the light-condensing portion; and .Iaddend. a
display panel disposed over the optical module to display an image
using light from the optical module.
15. The display device of claim 14, wherein the light sources have
a first number and the optical unit receives the light from the
light sources to form images of the light sources, the images
having a second number that is greater than the first number.
16. The display device of claim 15, wherein the optical module
further comprises an optical member configured to receive light
from the optical unit to emit light having substantially uniform
luminance with respect to a front direction of the base, wherein
the images of the light sources are formed between the optical unit
and the optical member.
17. The .[.optical unit.]. .Iadd.display device .Iaddend.of claim
14, wherein the first and second curved slant faces are connected
at a rounded top portion.
18. The display device of claim 17, wherein the first curved slant
face comprises a first face protruding from the base to form a
first angle with respect to the base and a second face extending
from an upper portion of the first face to form a second angle with
respect to the base, and the second curved slant face comprises a
third face protruding from the base toward the first face to form
the first angle with respect to the base and a fourth face
extending from an upper portion of the third face to be connected
to the second face, the fourth face forming the second angle with
respect to the base, wherein the first angle is larger than the
second angle.
19. The display device of claim 18, wherein the first and second
faces are connected at a first rounded portion, and the third and
fourth faces are connected at a second rounded portion.
.Iadd.20. An optical unit comprising: a base; a light-condensing
member comprising a first slant face protruding from the base and a
second slant face protruding from the base, the second slant face
being slanted toward the first slant face, wherein the first and
second slant faces are connected at a rounded top portion; and a
plurality of protrusion members protruding from a surface of the
light-condensing member except for the top portion of the
light-condensing member. .Iaddend.
.Iadd.21. The optical unit of claim 20, wherein at least one of the
first and second slant faces is convex. .Iaddend.
.Iadd.22. The optical unit of claim 20, wherein the rounded top
portion has a radius of curvature of about 0.05 times to about 0.7
times a pitch of neighboring light condensing members.
.Iaddend.
.Iadd.23. The optical unit of claim 20, wherein the first slant
face comprises a first face protruding from the base to form a
first angle with respect to the base, and a second face extending
from an upper portion of the first face to form a second angle with
respect to the base, and the second slant face comprises a third
face protruding from the base toward the first face to form the
first angle with respect to the base, and a fourth face extending
from an upper portion of the third face to be connected to the
second face, the fourth face forming the second angle with respect
to the base. .Iaddend.
.Iadd.24. The optical unit of claim 23, wherein the first angle is
larger than the second angle. .Iaddend.
.Iadd.25. The optical unit of claim 23, wherein the first and
second faces are connected at a first rounded portion, and the
third and fourth faces are connected at a second rounded portion.
.Iaddend.
.Iadd.26. The optical unit of claim 25, wherein the first, second,
third, and fourth faces respectively comprise flat surfaces.
.Iaddend.
.Iadd.27. The optical unit of claim 20, wherein the
light-condensing member has a surface roughness of about 0.1 to
about 10 micrometers root mean square. .Iaddend.
.Iadd.28. A backlight assembly comprising: a plurality of light
sources configured to generate light; an optical unit to condense
and diffuse the light, the optical unit comprising: a base; a
light-condensing member comprising a first slant face protruding
from the base and a second slant face protruding from the base, the
second slant face being slanted toward the first slant face,
wherein the first and second slant faces are connected at a rounded
top portion; and a protrusion member disposed on a surface of the
light-condensing member except for the top portion of the
light-condensing member. .Iaddend.
.Iadd.29. The backlight assembly of claim 28, wherein the light
sources comprise a first number of the light sources, and the
optical unit is configured to receive the light from the light
sources to form images of the light sources, the images comprising
a second number of the images that is greater than the first
number. .Iaddend.
.Iadd.30. The backlight assembly of claim 29, wherein the
light-condensing member is elongated along a longitudinal direction
of the light source. .Iaddend.
.Iadd.31. The backlight assembly of claim 28, wherein the first
slant face comprises a first face protruding from the base to form
a first angle with respect to the base and a second face extending
from an upper portion of the first face to form a second angle with
respect to the base, and the second slant face comprises a third
face protruding from the base toward the first face to form the
first angle with respect to the base, and a fourth face extending
from an upper portion of the third face to be connected to the
second face, the fourth face forming the second angle with respect
to the base, wherein the first angle is larger than the second
angle. .Iaddend.
.Iadd.32. The backlight assembly of claim 31, wherein the first and
second faces are connected at a first rounded portion, and the
third and fourth faces are connected at a second rounded portion.
.Iaddend.
.Iadd.33. The backlight assembly of claim 28, wherein the rounded
top portion has a radius of curvature of about 0.05 times to about
0.7 times a pitch of neighboring light condensing members.
.Iaddend.
.Iadd.34. The backlight assembly of claim 28, wherein the
light-condensing member has a surface roughness of about 0.1 to
about 10 micrometers root mean square. .Iaddend.
.Iadd.35. A display device comprising: a plurality of light sources
for generating light; an optical module to condense and diffuse the
light, the optical module comprising an optical unit including: a
base; a light-condensing member comprising a first slant face
protruding from the base and a second slant face protruding from
the base, the second slant face being slanted toward the first
slant face, wherein the first and second slant faces are connected
at a rounded top portion; and a protrusion member disposed on a
surface of the light-condensing member except for the top portion
of the light-condensing member; a display panel disposed over the
optical module to display an image using light from the optical
module. .Iaddend.
.Iadd.36. The display device of claim 35, wherein the light sources
comprise a first number of the light sources, and the optical unit
is configured to receive the light from the light sources to form
images of the light sources, the images comprising a second number
of the images that is greater than the first number. .Iaddend.
.Iadd.37. The display device of claim 36, wherein the optical
module further comprises an optical member configured to receive
light from the optical unit to emit light having substantially
uniform luminance with respect to a front direction of the base,
wherein the images of the light sources are formed between the
optical unit and the optical member. .Iaddend.
.Iadd.38. The display device of claim 37, wherein the distance
between the light source and the optical member is no more than
about 9 mm. .Iaddend.
.Iadd.39. The display device of claim 35, wherein the first slant
face comprises a first face protruding from the base to form a
first angle with respect to the base, and a second face extending
from an upper portion of the first face to form a second angle with
respect to the base, and the second slant face comprises a third
face protruding from the base toward the first face to form the
first angle with respect to the base, and a fourth face extending
from an upper portion of the third face to be connected to the
second face, the fourth face forming the second angle with respect
to the base, wherein the first angle is larger than the second
angle. .Iaddend.
.Iadd.40. The display device of claim 39, wherein the first and
second faces are connected at a first rounded portion, and the
third and fourth faces are connected at a second rounded portion.
.Iaddend.
.Iadd.41. The display device of claim 35, wherein the rounded top
portion has a radius of curvature of about 0.05 times to about 0.7
times a pitch of neighboring light condensing members.
.Iaddend.
.Iadd.42. The display device of claim 35, wherein the
light-condensing member has a surface roughness of about 0.1 to
about 10 micrometers root mean square. .Iaddend.
.Iadd.43. An optical unit comprising: a base; a light-condensing
member comprising a first slant face protruding from the base and a
second slant face protruding from the base, the second slant face
being slanted toward the first slant face; and a plurality of
protrusion members protruding from a surface of the
light-condensing member such that the light-condensing member has a
surface roughness of about 0.1 to about 10 micrometers root mean
square. .Iaddend.
.Iadd.44. The optical unit of claim 43, wherein at least one of the
first and second slant faces is convex. .Iaddend.
.Iadd.45. The optical unit of claim 43, wherein the first and
second slant faces are connected at a rounded top portion.
.Iaddend.
.Iadd.46. The optical unit of claim 45, wherein the
light-condensing member has a rounded top portion having a radius
of curvature of about 0.05 times to about 0.7 times a pitch of
neighboring light condensing members. .Iaddend.
.Iadd.47. The optical unit of claim 43, wherein the first slant
face comprises a first face protruding from the base to form a
first angle with respect to the base, and a second face extending
from an upper portion of the first face to form a second angle with
respect to the base, and the second slant face comprises a third
face protruding from the base toward the first face to form the
first angle with respect to the base, and a fourth face extending
from an upper portion of the third face to be connected to the
second face, the fourth face forming the second angle with respect
to the base. .Iaddend.
.Iadd.48. The optical unit of claim 47, wherein the first angle is
larger than the second angle. .Iaddend.
.Iadd.49. The optical unit of claim 47, wherein the first and
second faces are connected at a first rounded portion, and the
third and fourth faces are connected at a second rounded portion.
.Iaddend.
.Iadd.50. The optical unit of claim 49, wherein the first, second,
third, and fourth faces respectively comprise flat surfaces.
.Iaddend.
.Iadd.51. The optical unit of claim 43, wherein the protrusion
member is disposed on the surface of the light-condensing member
except for a top portion of the light-condensing member.
.Iaddend.
.Iadd.52. A backlight assembly comprising: a plurality of light
sources configured to generate light; an optical unit to condense
and diffuse the light, the optical unit comprising: a base; a
light-condensing member comprising a first slant face protruding
from the base and a second slant face protruding from the base, the
second slant face being slanted toward the first slant face; and a
protrusion member disposed on a surface of the light-condensing
member such that the light-condensing member has a surface
roughness of about 0.1 to about 10 micrometers root mean square.
.Iaddend.
.Iadd.53. The backlight assembly of claim 52, wherein the light
sources comprise a first number of the light sources, and the
optical unit is configured to receive the light from the light
sources to form images of the light sources, the images comprising
a second number of the images that is greater than the first
number. .Iaddend.
.Iadd.54. The backlight assembly of claim 53, wherein the
light-condensing member is elongated along a longitudinal direction
of the light source. .Iaddend.
.Iadd.55. The backlight assembly of claim 52, wherein the first and
second slant faces are connected at a rounded top portion.
.Iaddend.
.Iadd.56. The backlight assembly of claim 55, wherein the first
slant face comprises a first face protruding from the base to form
a first angle with respect to the base, and a second face extending
from an upper portion of the first face to form a second angle with
respect to the base, and the second slant face comprises a third
face protruding from the base toward the first face to form the
first angle with respect to the base, and a fourth face extending
from an upper portion of the third face to be connected to the
second face, the fourth face forming the second angle with respect
to the base, wherein the first angle is larger than the second
angle. .Iaddend.
.Iadd.57. The backlight assembly of claim 56, wherein the first and
second faces are connected at a first rounded portion, and the
third and fourth faces are connected at a second rounded portion.
.Iaddend.
.Iadd.58. The backlight assembly of claim 55, wherein the
light-condensing member has a rounded top portion having a radius
of curvature of about 0.05 times to about 0.7 times a pitch of
neighboring light condensing members. .Iaddend.
.Iadd.59. The backlight assembly of claim 52, wherein the
protrusion member is disposed on the surface of the
light-condensing member except for a top portion of the
light-condensing member. .Iaddend.
.Iadd.60. A display device comprising: a plurality of light sources
to generate light; an optical module to condense and diffuse the
light, the optical module comprising an optical unit including: a
base; a light-condensing member comprising a first slant face
protruding from the base and a second slant face protruding from
the base, the second slant face being slanted toward the first
slant face; and a protrusion member disposed on a surface of the
light-condensing member such that the light-condensing member has a
surface roughness of about 0.1 to about 10 micrometers root mean
square; a display panel disposed over the optical module to display
an image using light from the optical module. .Iaddend.
.Iadd.61. The display device of claim 60, wherein the light sources
comprise a first number of the light sources, and the optical unit
is configured to receive the light from the light sources to form
images of the light sources, the images comprising a second number
of the images that is greater than the first number. .Iaddend.
.Iadd.62. The display device of claim 61, wherein the optical
module further comprises an optical member configured to receive
light from the optical unit to emit light having substantially
uniform luminance with respect to a front direction of the base,
wherein the images of the light sources are formed between the
optical unit and the optical member. .Iaddend.
.Iadd.63. The display device of claim 62, wherein the distance
between the light source and the optical member is no more than
about 9 mm. .Iaddend.
.Iadd.64. The display device of claim 60, wherein the first and
second slant faces are connected at a rounded top portion.
.Iaddend.
.Iadd.65. The display device of claim 64, wherein the first slant
face comprises a first face protruding from the base to form a
first angle with respect to the base, and a second face extending
from an upper portion of the first face to form a second angle with
respect to the base, and the second slant face comprises a third
face protruding from the base toward the first face to form the
first angle with respect to the base, and a fourth face extending
from an upper portion of the third face to be connected to the
second face, the fourth face forming the second angle with respect
to the base, wherein the first angle is larger than the second
angle. .Iaddend.
.Iadd.66. The display device of claim 65, wherein the first and
second faces are connected at a first rounded portion, and the
third and fourth faces are connected at a second rounded portion.
.Iaddend.
.Iadd.67. The display device of claim 64, wherein the
light-condensing member has a rounded top portion having a radius
of curvature of about 0.05 times to about 0.7 times a pitch of
neighboring light condensing members. .Iaddend.
.Iadd.68. The display device of claim 60, wherein the protrusion
member is disposed on the surface of the light-condensing member
except for a top portion of the light-condensing member.
.Iaddend.
.Iadd.69. An optical unit comprising: a base; a light-condensing
member comprising a first slant face protruding from the base and a
second slant face protruding from the base, the second slant face
being slanted toward the first slant face; and a plurality of
protrusion members protruding from a surface of the
light-condensing member, wherein the light-condensing member has a
rounded top portion having a radius of curvature of about 0.05
times to about 0.7 times a pitch of neighboring light condensing
members. .Iaddend.
.Iadd.70. The optical unit of claim 69, wherein at least one of the
first and second slant faces is convex. .Iaddend.
.Iadd.71. The optical unit of claim 70, wherein the
light-condensing member has a rounded bottom portion having a
radius of curvature of about 0.05 times to about 0.7 times a pitch
of neighboring light condensing members. .Iaddend.
.Iadd.72. The optical unit of claim 69, wherein the first slant
face comprises a first face protruding from the base to form a
first angle with respect to the base, and a second face extending
from an upper portion of the first face to form a second angle with
respect to the base, and the second slant face comprises a third
face protruding from the base toward the first face to form the
first angle with respect to the base, and a fourth face extending
from an upper portion of the third face to be connected to the
second face, the fourth face forming the second angle with respect
to the base. .Iaddend.
.Iadd.73. The optical unit of claim 72, wherein the first angle is
larger than the second angle. .Iaddend.
.Iadd.74. The optical unit of claim 72, wherein the first and
second faces are connected at a first rounded portion, and the
third and fourth faces are connected at a second rounded portion.
.Iaddend.
.Iadd.75. The optical unit of claim 74, wherein the first, second,
third, and fourth faces respectively comprise flat surfaces.
.Iaddend.
.Iadd.76. The optical unit of claim 69, wherein the protrusion
members are disposed on the surface of the light-condensing member
except for a top portion of the light-condensing member.
.Iaddend.
.Iadd.77. The optical unit of claim 69, wherein the protrusion
members are disposed such that the light-condensing member has a
surface roughness of about 0.1 to about 10 micrometers root mean
square. .Iaddend.
.Iadd.78. A backlight assembly comprising: a plurality of light
sources configured to generate light; an optical unit to condense
and diffuse the light, the optical unit comprising: a base; a
light-condensing member comprising a first slant face protruding
from the base and a second slant face protruding from the base, the
second slant face being slanted toward the first slant face; and a
protrusion member disposed on a surface of the light-condensing
member, wherein the light-condensing member has a rounded top
portion having a radius of curvature of about 0.05 times to about
0.7 times a pitch of neighboring light condensing members.
.Iaddend.
.Iadd.79. The backlight assembly of claim 78, wherein the light
sources comprise a first number of the light sources, and the
optical unit is configured to receive the light from the light
sources to form images of the light sources, the images comprising
a second number of the images that is greater than the first
number. .Iaddend.
.Iadd.80. The backlight assembly of claim 79, wherein the
light-condensing member is elongated along a longitudinal direction
of the light source. .Iaddend.
.Iadd.81. The backlight assembly of claim 79, wherein the
light-condensing member has a rounded bottom portion having a
radius of curvature of about 0.05 times to about 0.7 times a pitch
of neighboring light condensing members. .Iaddend.
.Iadd.82. The backlight assembly of claim 81, wherein the first
slant face comprises a first face protruding from the base to form
a first angle with respect to the base, and a second face extending
from an upper portion of the first face to form a second angle with
respect to the base, and the second slant face comprises a third
face protruding from the base toward the first face to form the
first angle with respect to the base, and a fourth face extending
from an upper portion of the third face to be connected to the
second face, the fourth face forming the second angle with respect
to the base, wherein the first angle is larger than the second
angle. .Iaddend.
.Iadd.83. The backlight assembly of claim 82, wherein the first and
second faces are connected at a first rounded portion, and the
third and fourth faces are connected at a second rounded portion.
.Iaddend.
.Iadd.84. The backlight assembly of claim 78, wherein the
protrusion member is disposed on the surface of the
light-condensing member except for a top portion of the
light-condensing member. .Iaddend.
.Iadd.85. The backlight assembly of claim 78, wherein the
protrusion member is disposed such that the light-condensing member
has a surface roughness of about 0.1 to about 10 micrometers root
mean square. .Iaddend.
.Iadd.86. A display device comprising: a plurality of light sources
to generate light; an optical module to condense and diffuse the
light, the optical module comprising an optical unit including: a
base; a light-condensing member comprising a first slant face
protruding from the base and a second slant face protruding from
the base, the second slant face being slanted toward the first
slant face, wherein the light-condensing member has a rounded top
portion having a radius of curvature of about 0.05 times to about
0.7 times a pitch of neighboring light condensing members; and a
protrusion member disposed on a surface of the light-condensing
member; a display panel disposed over the optical module to display
an image using light from the optical module. .Iaddend.
.Iadd.87. The display device of claim 86, wherein the light sources
comprise a first number of the light sources, and the optical unit
is configured to receive the light from the light sources to form
images of the light sources, the images comprising a second number
of the images that is greater than the first number. .Iaddend.
.Iadd.88. The display device of claim 87, wherein the optical
module further comprises an optical member configured to receive
light from the optical unit to emit light having substantially
uniform luminance with respect to a front direction of the base,
wherein the images of the light sources are formed between the
optical unit and the optical member. .Iaddend.
.Iadd.89. The display device of claim 88, wherein the distance
between the light source and the optical member is no more than
about 9 mm. .Iaddend.
.Iadd.90. The display device of claim 86, wherein the
light-condensing member has a rounded bottom portion having a
radius of curvature of about 0.05 times to about 0.7 times a pitch
of neighboring light condensing members. .Iaddend.
.Iadd.91. The display device of claim 90, wherein the first slant
face comprises a first face protruding from the base to form a
first angle with respect to the base, and a second face extending
from an upper portion of the first face to form a second angle with
respect to the base, and the second slant face comprises a third
face protruding from the base toward the first face to form the
first angle with respect to the base, and a fourth face extending
from an upper portion of the third face to be connected to the
second face, the fourth face forming the second angle with respect
to the base, wherein the first angle is larger than the second
angle. .Iaddend.
.Iadd.92. The display device of claim 91, wherein the first and
second faces are connected at a first rounded portion, and the
third and fourth faces are connected at a second rounded portion.
.Iaddend.
.Iadd.93. The display device of claim 86, wherein the protrusion
member is disposed on the surface of the light-condensing member
except for a top portion of the light-condensing member.
.Iaddend.
.Iadd.94. The display device of claim 86, wherein the protrusion
member is disposed such that the light-condensing member has a
surface roughness of about 0.1 to about 10 micrometers root mean
square. .Iaddend.
Description
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to an optical unit, a backlight
assembly having the optical unit and a display device having the
optical unit. More particularly, the present invention relates to
an optical unit capable of condensing and diffusing light, a
backlight assembly having the optical unit and a display device
having the optical unit.
2. Description of the Related Art
Generally, a backlight assembly of a display device is classified
as either all edge illumination type backlight assembly or a direct
illumination type backlight assembly.
The edge illumination type backlight assembly includes a light
guiding plate and a lamp disposed at a side of the light guiding
plate. The edge illumination type backlight assembly is usually
employed in a display device having a relatively small display
size. The edge illumination type backlight assembly has many
merits, such as good optical uniformity, long lifetime, small size,
etc.
The direct illumination type backlight assembly has been developed
as the size of liquid crystal display (LCD) devices has increased
over time. The direct illumination type backlight assembly includes
a plurality of lamps disposed under a light-diffusing plate and
arranged substantially parallel to each other. The direct
illumination type backlight assembly includes more lamps than the
edge illumination type backlight assembly, and thus has a
relatively high luminance.
However, in a direct illumination type backlight assembly, the lamp
configuration may be detected through the light-diffusing plate.
Therefore, the display quality of a display device employing a
direct illumination type backlight assembly may be lower than the
display quality of a display device employing an edge illumination
type backlight assembly.
SUMMARY OF THE INVENTION
Systems and techniques provided herein may reduce or eliminate
drawbacks of existing direct illumination type backlight
assemblies. In embodiments of the invention, an optical unit
configured to condense and diffuse externally-provided light is
disclosed.
Embodiments of the present invention also provide a backlight
assembly having the above-mentioned optical unit to irradiate light
having enhanced luminance uniformity.
Embodiments of the present invention also provide a display device
having the above-mentioned backlight assembly.
In one aspect of the present disclosure, an optical unit includes a
base, a light-condensing member and a plurality of protrusion
members. The light-condensing member is disposed on the base to
condense a first portion of light that is incident onto the base.
The protrusion members are disposed on a surface of the
light-condensing member to scatter a second portion of the light
that is incident onto the base.
The light-condensing member may include a first slant face and a
second slant face. The first slant face protrudes from the base to
form a first obtuse angle with respect to the base. The second
slant face protrudes from the base and is slanted toward the first
slant face.
The light-condensing member optionally includes a third slant face
and a fourth slant face. The third slant face extends from an upper
portion of the first slant face to form a second obtuse angle. The
fourth slant face extends from an upper portion of the second slant
face and connected to the third slant face.
The light-condensing member optionally includes a horizontal face
substantially parallel to the base and connected to the first and
second slant faces.
In another aspect of the present disclosure, a backlight assembly
includes a light source, an optical unit and an optical member. The
light source generates light. The optical unit includes a
light-condensing portion and a protrusion portion. The
light-condensing portion is disposed on a base to condense a first
portion of the light generated from the light source. The
protrusion portion is disposed on a surface of the light-condensing
portion to scatter a second portion of the light generated from the
light source. The optical member receives light from the optical
unit and is configured to emit light having substantially uniform
luminance with respect to a front direction of the base.
The backlight assembly may include a plurality of light sources.
Images of the light sources, which have a second number that is
greater than a first number of the light sources, are formed
between the optical unit and the optical member. The
light-condensing portion may have various shapes. The
light-condensing portion, for example, includes slant faces. A
portion at which slant faces and the base are connected and a
portion at which slant faces are connected with each other may have
a rounded portion having a predetermined radius of curvature.
In still another aspect of the present disclosure, a display device
includes a plurality of light sources, an optical module and a
display panel. The light sources generate light, and have a first
number. The optical module receives the light from the light
sources to form images of the light sources. The images have a
second number that is greater than the first number. The optical
module may emit light having substantially uniform luminance with
respect to a front direction of the optical module. The display
panel is disposed over the optical module to display an image using
light from the optical module.
According to the above, images of light sources, the number of
which may be at least double of the number of the light sources,
are formed between the optical unit and the optical member, and
light emitted from the light sources diffuses through the optical
unit. Thus, bright lines generated on the optical member may be
reduced, and display quality of the display device having the
optical unit may be enhanced.
BRIEF DESCRIPTION OF THE DRAWINGS
The above and other advantages of the present invention will become
readily apparent by reference to the following detailed description
when considered in conjunction with the accompanying drawings
wherein:
FIG. 1 is a cross-sectional view illustrating a portion of an
optical unit according to an exemplary embodiment of the present
invention;
FIG. 2 is a cross-sectional view illustrating a portion of an
optical unit according to another exemplary embodiment of the
present invention;
FIG. 3 is a cross-sectional view illustrating a portion of an
optical unit according to still another exemplary embodiment of the
present invention;
FIG. 4 is a cross-sectional view illustrating a portion of an
optical unit according to still another exemplary embodiment of the
present invention;
FIG. 5 is a cross-sectional view illustrating a portion of a
backlight assembly according to an exemplary embodiment of the
present invention;
FIG. 6 is a plan view illustrating a portion of lamps viewed
through an optical unit shown in FIG. 5;
FIG. 7 is a cross-sectional view illustrating a position of a lamp
image formed over an optical unit of the backlight assembly shown
in FIG. 5;
FIG. 8 is a graph illustrating a relationship between a first
distance `Z` and a second distance `D` in FIG. 7; and
FIG. 9 is a cross-sectional view illustrating a display device
according to an exemplary embodiment of the present invention.
DESCRIPTION OF THE EMBODIMENTS
The present invention now will be described more fully hereinafter
with reference to the accompanying drawings, in which embodiments
of the invention are shown. This invention may, however, be
embodied in many different forms and should not be construed as
limited to the embodiments set forth herein; rather, these
embodiments are provided so that this disclosure will be thorough
and complete, and will fully describe the invention to those
skilled in the art. Like reference numerals refer to similar or
identical elements throughout.
Optical Unit
FIG. 1 is a cross-sectional view illustrating a portion of an
optical unit according to an example embodiment of the present
invention.
Referring to FIG. 1, an optical unit 130 includes a base 131, a
light condenser such as light-condensing member 133, and protrusion
members 139.
The base 131 serves as a body of the optical unit 130. The base 131
may include a transparent material having a high optical
transmissivity, for example, base 131 may include a material such
as polyethylene terephthalate (PET).
The light-condensing member 133 is disposed on or over the base
131. The light-condensing member 133 may have various shapes. For
example, the light-condensing member 133 may have a rod shape that
is elongated along one direction, and may have a substantially
polygonal cross section (e.g., a substantially triangular cross
section as shown in FIG. 1). The optical unit may include a
plurality of light condensing members 133, and the light condensing
members are disposed substantially parallel to each other. The
light-condensing member 133, for example, may include a material
that is substantially the same material as that of the base 131.
The light-condensing member 133 may include polymethyl methacrylate
(PMMA), which has advantageous characteristics such as good heat
resistance, high optical transmissivity, good chemical resistance,
etc.
As noted above, a cross-section of the light-condensing member 133,
which is substantially perpendicular to a longitudinal direction of
the light-condensing member 133, may have a polygonal shape. The
light-condensing member 133 may have various geometrical structures
for changing an optical path of light provided into the optical
unit 130 toward a front direction of the optical unit 130.
In some embodiments, the light-condensing member 133 includes a
first slant face 134 and a second slant face 135. The first slant
face 134 protrudes from the base 131 to form a first obtuse angle
.theta.1 with respect to the base 131. The second slant face 135
protrudes from the base 131 and faces the first slant face 134. The
second slant face 135 is slanted toward the first slant face
134.
As shown in FIG. 1, the first slant face 134 and the second slant
face 135 are substantially symmetrical to each other with respect
to a plane that is substantially perpendicular to the base 131. The
first and second slant faces 134 and 135 are elongated along the
longitudinal direction of the light-condensing member 133 (into the
page of FIG. 1).
In order to effectively condense the light provided into the base
131 toward the front direction of the optical unit 130, the first
and second slant faces 134 and 135 may preferably form an angle
.phi. of about thirty degrees to about one hundred fifty
degrees.
The first and second slant faces 134 and 135 are connected with
each other at a top portion, and the top portion may be rounded.
The first and second slant faces 134 and 135 are connected with
base 131 at a bottom portion, and the bottom portion may be
rounded.
When the top portion and the bottom portion, at which the base 131,
the first slant face 134 and the second slant face 135 are
connected with each other, have a rounded portion, light may
effectively diffuse through the rounded portion. Thus, compared to
a configuration where the portion is not rounded, the appearance of
bright lines (when viewed over the optical unit 130) may be
reduced.
The rounded portion of the top portion and the bottom portion may
preferably have a radius of curvature in a range of about 0.05
times to about 0.7 times a pitch of the light-condensing member
133. The pitch P of the light-condensing member 133 is defined as
an interval between neighboring top portions or between neighboring
bottom portions (as indicated in the example illustrated in FIG.
1).
In the embodiment shown in FIG. 1, the light-condensing member 133
includes the first and second slant faces 134 and 135 that comprise
generally flat surfaces. Alternatively, the light-condensing member
133 may include a slant face comprising a curved surface. For
example, the light-condensing member 133 may include a first curved
slant face that protrudes from the base 131 and a second curved
slant face that protrudes from the base 131 and is connected to the
first curved slant face. At least one of the first and second
curved slant faces may be convex. Further, at least one of the
first and second curved slant faces may be concave.
The protrusion members 139 protrude from a surface of
light-condensing member 133. The protrusion members 139 cover a
portion of the surface of the light-condensing member 133. A
protruded amount and a protruded size of each protrusion member 139
may be varied. The protrusion members 139 are formed such that the
light-condensing member 133 has a surface roughness of about 0.1 to
about 10 micrometers root mean square.
FIG. 2 is a cross-sectional view illustrating a portion of an
optical unit according to another exemplary embodiment of the
present invention.
Referring to FIG. 2, an optical unit 230 includes a base 231, a
light-condensing member 233 and protrusion members 239. The
exemplary optical unit 230 shown in FIG. 2 is substantially
identical to the exemplary optical unit 130 shown in FIG. 1 except
for the number of slant faces of the light-condensing member
233.
The light-condensing member 233 includes first, second, third and
fourth slant faces 234, 235, 236 and 237, which are elongated along
a longitudinal direction of the light-condensing member 233 (into
the page of FIG. 2).
The first slant face 234 protrudes from the base 231 to form a
first obtuse angle .theta.2 with respect to the base 231. The
second slant face 235 protrudes from the base 231 and faces the
first slant face 234. The second slant face 235 is slanted toward
the first slant face 234. As shown in FIG. 2, the first slant face
234 and the second slant face 235 are substantially symmetrical to
each other with respect to a plane that is substantially
perpendicular to the base 231 (i.e., a plane that extends
vertically and into the page of FIG. 2).
The third slant face 236 extends from an upper portion of the first
slant face 234 to form a second obtuse angle .theta.3 with respect
to the base 231. The fourth slant face 237 extends from an upper
portion of the second slant face 235 and is thus connected to the
third slant face 236. As shown in FIG. 2, the third slant face 236
and the fourth slant face 237 are substantially symmetrical to each
other with respect to a plane that is substantially perpendicular
to the base 231 (i.e., a plane that extends vertically and into the
page of FIG. 2).
The first obtuse angle .theta.2 and the second obtuse angle
.theta.3 are different from one another. As shown in FIG. 2, the
second obtuse angle .theta.3 is greater than the first obtuse angle
.theta.2. The third and fourth slant faces 236 and 237 may
preferably form an angle .phi. of about thirty degrees to about one
hundred fifty degrees.
The first and second slant faces 234 and 235 are connected with
base 231 at a bottom portion, and the third and fourth slant faces
236 and 237 are connected with each other at a top portion. The
bottom portion and the top portion may be rounded to have a
predetermined radius of curvature.
FIG. 3 is a cross-sectional view illustrating a portion of an
optical unit 330 according to still another exemplary embodiment of
the present invention.
Referring to FIG. 3, an optical unit 330 includes a base 331, a
light-condensing member 333 and protrusion members 339. The
light-condensing member 333 includes first, second, third and
fourth slant faces 334, 335, 336 and 337.
In the exemplary embodiment shown in FIG. 3, the optical unit 330
is substantially identical to the exemplary optical unit 230 shown
in FIG. 2 except for a first angle .theta.4 being greater than a
second angle .theta.5. Here, the first slant face 334 and the
second slant face 335 form the first angle .theta.4 with respect to
the base 331, and the third slant face 336 and the fourth slant
face 337 form the second angle .theta.5 with respect to the base
331.
FIG. 4 is a cross-sectional view illustrating a portion of an
optical unit 430 according to still another exemplary embodiment of
the present invention.
Referring to FIG. 4, an optical unit 430 includes a base 431, a
light-condensing member 433 and protrusion members 439.
The light-condensing member 433 is disposed on a surface of the
base 431. The light-condensing member 433 includes a first slant
face 434, a second face 435 and a horizontal face 436.
The first slant face 434 protrudes from the base 431 to form a
first obtuse angle .theta.6 with respect to the base 431. The
second slant face 435 protrudes from the base 431 and faces the
first slant face 434. The second slant face 435 is slanted toward
the first slant face 434. As shown in FIG. 4, the first slant face
434 and the second slant face 435 are substantially symmetrical to
each other with respect to a plane that is substantially
perpendicular to the base 431 (i.e., a plane that extends
vertically and into the page of FIG. 4).
The horizontal face 436 is substantially parallel to the base 431.
A first end portion of the horizontal face 436 is connected to an
upper portion of the first slant face 434, and a second end portion
of the horizontal face 436, which faces the first end portion, is
connected to an upper portion of the second slant face 435.
Backlight Assembly
FIG. 5 is a cross-sectional view illustrating a portion of a
backlight assembly 100 according to an exemplary embodiment of the
present invention.
Referring to FIG. 5, a backlight assembly 100 includes a plurality
of light sources 110, an optical unit 130 and an optical member
150. The optical unit 130 shown in FIG. 5 is substantially
identical to the optical unit 130 shown in FIG. 1. Thus, the same
reference numerals will be used to refer to the corresponding parts
and further description concerning the corresponding parts may be
omitted. Hereinafter, the light-condensing member 133 referred to
in the description associated with FIG. 1 will be referred to as a
light-condensing portion, and the protrusion member 139 referred to
in the description associated with FIG. 1 will be referral to as a
protrusion portion.
The light sources 110 may include at least one of a fluorescent
lamp, a surface light source, and a light emitting diode. The
backlight assembly 100, for example, includes lamps 110 having a
substantially linear and tubular shape. The lamps 110 are
substantially parallel to each other.
In some embodiments, each of the lamps 110 includes a lamp tube and
electrode parts. The lamp tube, for example, includes glass. A
fluorescent material is coated on an inner surface of the lamp
tube, and discharge gas is charged in an inner space of the lamp
tube. A discharge voltage (which may be provided externally) is
applied to the electrode parts, so that the discharge gas generates
light having a wavelength outside the visible spectrum. The
fluorescent material converts the light into visible light (light
having a wavelength in the visible spectrum).
The optical unit 130 changes an optical path of a first portion of
light provided from the lamps to face a front direction of the
optical unit 130, and scatters a second portion of the light
provided from the lamps, as described further below. The optical
unit 130 is spaced apart from the lamps 110 by a predetermined
distance, and includes a base 131, a light-condensing portion 133
and protrusion portions 139.
FIG. 6 is a plan view illustrating a portion of lamps viewed
through an optical unit such as optical unit 130 shown in FIG.
5.
Referring to FIGS. 5 and 6, the light emitted from the lamps 110 is
incident onto the base 131 of the optical unit 130. A portion 134A
of the incident light passes through a region of first slant face
134 on which protrusions are not formed, while a portion 135A of
the incident light passes through a region of second slant face 135
on which protrusion portions 139 are not formed. For convenience,
the description below will be based on a cross-section of the
light-condensing portion 133 which is substantially perpendicular
to the longitudinal direction of the light-condensing portion 133
(such as the cross section illustrated in FIG. 5).
When the portion 134A is incident onto the first slant face 134 at
a predetermined clockwise angle with respect to a normal line to
the first slant face 134, the light is refracted such that the
direction of the transmitted light is more aligned with a front
direction F of the base 131.
When the portion 134A is incident onto the first slant face 134 at
a predetermined counterclockwise angle with respect to a normal
line to the first slant face 134, the light is refracted such that
the direction of the transmitted light is less aligned with the
front direction of the base 131. Light passing through the
protrusion portions 139 is scattered.
As a result, for each of the lamps 110, there are two positions at
which light is condensed in the front direction of the optical unit
130. Two lamp images 111 are formed at the two positions associated
with each of the lamps 110, so that the number of lamp images 111
is twice the number of lamps 110.
Lamp images 111 are formed over the optical unit 130. Since a
portion of the incident light diffuses when exiting through the
protrusion portions 139, a second luminance of the lamp images 111
is reduced compared to a first luminance of the associated lamp of
the lamps 110.
The optical member 150 receives light from the optical unit 130,
and emits light having enhanced optical characteristics; for
example, enhanced luminance uniformity. In some embodiments, the
optical member 150 is separated from the optical unit 130 by a
sufficient distance so that the lamp images 111 are formed between
the optical unit 130 and the optical member 150. The optical member
150, for example, includes a base body, diffusion beads disposed on
the base body to diffuse incident light, and binders disposed
between the diffusion beads to fasten the diffusion beads to the
base body.
As noted above, the second number of the lamp images 111 formed
between the optical unit 130 and the optical member 150 may be
about double of the first number of the lamps 110, and the second
luminance of the lamp images 111 is reduced in comparison with the
first luminance of the lamps 110. As a result, a second interval
between adjacent lamp images 111 is smaller than a first interval
between adjacent lamps 110.
Accordingly, the luminance distribution of light entering the
optical member 150 becomes more uniform. The luminance distribution
of light entering optical member 150 may substantially reduce or
eliminate the detection of bright lines in the light transmitted
through optical member 150.
Even though the second number of the lamp images 111 is about
double the first number of the lamps 110, the bright lines may be
detected in the light transmitted through the optical member 150
when the second luminance of the lamp images 111 is relatively
high.
However, according to the present disclosure, a portion of the
light that is incident onto the base 131 diffuses when exiting
through the protrusion portions 139 formed on the light-condensing
portion 133. Thus, the amount of light refracted through the
light-condensing portion 133 toward the front direction of the
optical unit 130 to form lamp images 111 is reduced. As a result
the second luminance of the lamp images 111 decreases, and the
detection of bright lines in the light transmitted through optical
member 150 corresponding to the lamp images 111 may be
substantially reduced or prevented.
Accordingly, even though a distance between the lamps 110 and the
optical member 150 of the backlight assembly 100 may be shorter
than that of a conventional backlight assembly (for example, the
distance may be about 9 mm or less), the bright lines may be
reduced. Hence, the backlight assembly 100 may be made relatively
thin, compared to conventional backlight assemblies.
FIG. 7 is a cross-sectional view illustrating a position of a lamp
image 111 formed over an optical unit 130 of the backlight assembly
100 shown in FIG. 5. FIG. 8 is a graph illustrating a relationship
between a first distance `Z` and a second distance `D` in FIG.
7.
Referring to FIGS. 7 and 8, the first distance `Z` is defined as a
distance from the lamps 110 to an upper face of the base 131 on
which the light-condensing portion 133 is formed, and the second
distance `D` is defined as a distance from an axis, which passes
through a center of the lamp 110 and is substantially perpendicular
to the base 131, to one of the lamp images 111 associated with that
lamp 110.
When the first distance `Z` increases, the second distance `D` also
increases. When the first distance `Z` decreases, the second
distance `D` also decreases. Thus, when the first distance `Z`
decreases, a distance between two lamp images 111 adjacent to each
other, which corresponds to 2.times.x`D`, decreases. When the
distance between the two lamp images 111 becomes too small, the two
lamp images 111 may be hard to distinguish from one another, so
that the two lamp images 111 may be recognized as one image.
When the first distance `Z` becomes too large, two lamp images 111
adjacent to each other of four lamp images 111 generated from two
lamps 110 may be difficult to distinguish from one another.
Accordingly, the first distance `Z` may be determined, such that
the distances between adjacent lamp images 111 may be substantially
uniform and the lamp images 111, which have the second number that
is greater than the first number of the lamps 110, may be formed to
reduce the bright lines.
For example, in some embodiments, the distance between the lamps
110 and the optical member 150 is no more than about 9 mm. The
first distance `Z` is equal to the difference between the distance
between the lamps 110 and the optical member 150 and the distance
between the optical member 150 and the optical unit 130.
Display Device
FIG. 9 is a cross-sectional view illustrating a display device
according to an example embodiment of the present invention.
Referring to FIG. 9, a display device 600 includes a plurality of
light sources 610, an optical module 670 and a display panel
690.
The light sources 610 illustrated in FIG. 9 are substantially
identical to the light sources in FIGS. 5 to 8. Many types of light
sources may be used.
The optical module 670 is disposed over the light sources 610 to
form images using light provided from the light sources 610. The
number of the images is greater than the number of the light
sources 610. Light, a luminance distribution of which is
substantially uniform with respect to a front of the optical module
670, exits the optical module 670. The optical module 670 includes
an optical unit 630 and an optical member 650.
The optical unit 630 and the optical member 650 illustrated in FIG.
9 are substantially identical to the optical unit 130 and the
optical member 150, which are shown in FIGS. 5 to 8. However, other
configurations may be used (e.g., different numbers of protrusions
639, different shapes, different relative placements and sizes,
etc.). The optical unit 630 may include a body 631, a
light-condensing portion 633 and protrusion portions 639, which
correspond to the base 131, the light-condensing member 133 and the
protrusion members 139 shown in FIG. 5, respectively.
Light is incident onto the body 631 and then passes through the
light-condensing portion 633. A portion of the light passing
through the light-condensing portion 633 is refracted and condensed
in a front direction F of the optical unit 630. Thus, images 611
having a first number are formed. The first number of the images
611 is greater than a second number of the light sources 610. The
images 611 are formed between the optical unit 630 and the optical
member 650. Light passing through each of the protrusion portions
639 is scattered to exit the optical unit 630.
The optical member 650 enhances optical characteristics, such as
the luminance uniformity of light emitted from the optical unit
630, and thus light having the enhanced optical characteristics
exits the optical member 650.
The optical module 670 optionally includes a light-condensing sheet
660. The light-condensing sheet 660 increases the front luminance
of the light by changing the optical path of the light to increase
the portion transmitted in the front direction F of display device
600.
The display panel 690 is disposed over the light-condensing sheet
660 to display an image using the light emitted from the
light-condensing sheet 660. The display panel 690 to includes a
first substrate 691, a second substrate 695 and a liquid crystal
layer (not shown). The first and second substrates 691 and 695 face
each other. The liquid crystal layer is disposed between the first
and second substrates 691 and 695.
The first substrate 691 may include a plurality of first electrodes
that are arranged in a matrix configuration and a plurality of
switching elements each of which applies a predetermined voltage to
corresponding first electrodes. The second substrate 695 may
include a second electrode facing the first electrodes and a color
filter for displaying a predetermined color using externally
provided light.
When an electric power is applied to the first and second
electrodes, electric fields are generated between the first and
second electrodes. Molecules of the liquid crystal layer between
the first and second electrodes are oriented according to the local
electric field. Since the optical transmissivity of the liquid
crystal depends on the orientation of the molecules of the liquid
crystal material, the displayed image may be changed by changing
the voltages applied to the electrodes of the display panel
690.
According to the present disclosure, the optical unit condenses a
portion of light emitted from light sources toward a front
direction of the optical unit, and diffuses a remaining portion of
the light. Thus, lamp images, the number of which is about double
of the number of the lamps, are formed between the optical unit and
the optical member. Hence, the backlight assembly having the above
structure has substantially the same effect as a backlight assembly
including a larger number of light sources disposed at narrower
intervals.
In addition, the luminance of the lamp images is reduced in
comparison with the luminance of the lamps. Thus, bright lines
generated on the optical member decrease, and the display quality
of a display device having the optical unit may be enhanced.
Although the optical unit has been primarily discussed with
reference to the exemplary configuration of FIG. 1, other
configurations may be used. For example, configurations with
additional slant faces (e.g., as shown in FIGS. 2 and 3),
configurations with a horizontal portion (e.g., as shown in FIG.
4), and configurations with curved surfaces (concave and/or convex,
as described above). For these different configurations, the
associated light condensing portions condense light differently
than the configuration of FIG. 1. For example, the configuration of
FIG. 2 may provide for four lamp images for each lamp, rather than
two.
Although exemplary embodiments of the present invention have been
described, it is understood that the present invention should not
be limited to these exemplary embodiments but various changes and
modifications can be made by one ordinary skilled in the art within
the spirit and scope of the present invention as hereinafter
claimed.
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