U.S. patent number RE44,008 [Application Number 12/390,312] was granted by the patent office on 2013-02-19 for surface light source device and liquid crystal display device.
This patent grant is currently assigned to Sharp Kabushiki Kaisha. The grantee listed for this patent is Takafumi Hara, Tatsuya Kudari, Tatsuo Sugahara, Fujio Ueda. Invention is credited to Takafumi Hara, Tatsuya Kudari, Tatsuo Sugahara, Fujio Ueda.
United States Patent |
RE44,008 |
Sugahara , et al. |
February 19, 2013 |
Surface light source device and liquid crystal display device
Abstract
In a surface light source device including: a light source
section having a light emitting face; an optical panel arranged so
as to cover the light emitting face; and a at least one frame
having a front face portion that covers the peripheral portion of
the light emitting face, the at least one frame is composed of a
plurality of divisional members connected with each other and a
light shielding portion is provided at each slit between the
divisional members in the front face portion of the at least one
frame. Whereby, light from the light source section is prevented
from leaking through each slit between the divisional members in
the front face portion of the at least one frame.
Inventors: |
Sugahara; Tatsuo (Mie,
JP), Hara; Takafumi (Kyoto, JP), Ueda;
Fujio (Nabari, JP), Kudari; Tatsuya (Suzuka,
JP) |
Applicant: |
Name |
City |
State |
Country |
Type |
Sugahara; Tatsuo
Hara; Takafumi
Ueda; Fujio
Kudari; Tatsuya |
Mie
Kyoto
Nabari
Suzuka |
N/A
N/A
N/A
N/A |
JP
JP
JP
JP |
|
|
Assignee: |
Sharp Kabushiki Kaisha (Osaka,
JP)
|
Family
ID: |
34554284 |
Appl.
No.: |
12/390,312 |
Filed: |
February 20, 2009 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
Issue Date |
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Reissue of: |
10936506 |
Sep 9, 2004 |
7178968 |
Feb 20, 2007 |
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Foreign Application Priority Data
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Sep 10, 2003 [JP] |
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2003-318683 |
Aug 19, 2004 [JP] |
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2004-239881 |
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Current U.S.
Class: |
362/633;
362/97.2; 349/58; 362/613 |
Current CPC
Class: |
G02F
1/133608 (20130101); G02F 1/133308 (20130101); G02F
1/133328 (20210101) |
Current International
Class: |
F21V
7/04 (20060101) |
Field of
Search: |
;362/97.1-97.4,632-634
;349/58,60 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
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2000-75273 |
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Mar 2000 |
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JP |
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2000-314872 |
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Nov 2000 |
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JP |
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2001-209327 |
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Aug 2001 |
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JP |
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2001-249619 |
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Sep 2001 |
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JP |
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2002-258769 |
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Sep 2002 |
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JP |
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2002-268037 |
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Sep 2002 |
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JP |
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2002-290873 |
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Oct 2002 |
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JP |
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2003-5156 |
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Jan 2003 |
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JP |
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2003-50549 |
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Feb 2003 |
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JP |
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Primary Examiner: Han; Jason Moon
Attorney, Agent or Firm: Birch, Stewart, Kolasch &
Birch, LLP
Claims
What is claimed is:
.[.1. A surface light source device, comprising: a light source
section which has a light emitting face; an optical panel which is
arranged so as to cover the light emitting face of the light source
section and which performs a predetermined optical operation for
light from the light source section; and at least one frame which
includes a front face portion arranged so as to overlap with a
peripheral portion of the optical panel in a direction of a
thickness of the optical panel and a side face portion extending
from an outer periphery of the front face portion toward the light
source section and which is arranged along a peripheral portion of
the light emitting face of the light source section; wherein the at
least one frame is composed of a plurality of divisional members
divided in a direction along the peripheral portion of the light
emitting face of the light source section, which have a slit
between each divisional member, and a light shielding portion is
provided, at each said slit in the front face portion of the frame,
for preventing light of the light source section from leaking
through each said slit, wherein the divisional members include a
u-shaped member, and wherein the corner portion of the u-shaped
member is formed by drawing..].
.[.2. The surface light source device of claim 1, wherein the at
least one frame serves as a rear frame of which front face portion
is provided on the light source section side of the peripheral
portion of the optical panel so as to cover the peripheral portion
of the light emitting face of the light source section..].
.[.3. The surface light source device of claim 1 wherein the at
least one frame serves as a front frame of which front face portion
is provided on a side opposite the light source section side of the
peripheral portion of the optical panel so as to cover the
peripheral portion of the light emitting face of the light source
section..].
.[.4. The surface light source device of claim 1, wherein the at
least one frame includes: a rear frame of which front face portion
is provided on the light source section side of the peripheral
portion of the optical panel so as to cover the peripheral portion
of the light emitting face of the light source section; and a front
frame of which front face portion is provided on a side opposite
the light source section side of the peripheral portion of the
optical panel so as to cover the peripheral portion of the light
emitting face of the light source section..].
.[.5. The surface light source device of claim 1, wherein the
connection between the plural divisional members are carried out by
welding, and the light shielding portion is formed of a welded
portion formed by the welding..].
.[.6. The surface light source device of claim 5, wherein the
welded portion is formed at each slit between the plural divisional
members in the side face portion, in addition to each slit between
the plural divisional members in the front face portion..].
.[.7. A liquid crystal display device, comprising a surface light
source device according to any one of claims 2, 3, 4, 5, 6 and 1,
wherein the optical panel serves as a liquid crystal display panel
including a pair of transparent substrates and a liquid crystal
layer disposed between the pair of transparent substrates, and the
light source section serves as a backlight section for emitting
light to the liquid crystal display panel..].
.Iadd.8. A surface light source device, comprising: a light source
section which has a light emitting face; a liquid crystal display
panel which is arranged so as to cover the light emitting face of
the light source section; and at least one frame which includes a
front face portion arranged so as to overlap with a peripheral
portion of the liquid crystal display panel in a direction of a
thickness of the liquid crystal display panel and a side face
portion extending from an outer periphery of the front face portion
toward the light source section; wherein the at least one frame is
composed of a plurality of divisional members, said at least one
frame has a slit between each divisional member, and a light
shielding portion is provided, at said slit in the front face
portion of the frame, for preventing light of the light source
section from leaking through said slit, wherein the plurality of
divisional members are connected by welding, and the light
shielding portion is formed by a welded portion formed by the
welding, wherein the divisional members include a first and a
second divisional member each having two corner portions that
include two outside corner portions at an outermost edge of the
divisional member and wherein each of the two outside corner
portions respectively extend around two corners of a peripheral
edge portion of the liquid crystal display panel, and wherein the
light shielding portion provided in said slit is arranged in an
entire region in a widthwise direction across the front face
portion of the frame, wherein the at least one frame serves as a
front frame of which front face portion is provided on a side
opposite the light source section side of the peripheral portion of
the liquid crystal panel, wherein the slits have a step-like
cross-sectional shape that further prevents light of the light
source section from leaking through the slits..Iaddend.
.Iadd.9. The surface light source device of claim 8, wherein the
welded portion is formed at each slit between the plural divisional
members in the side face portion, in addition to each slit between
the plural divisional members in the front face
portion..Iaddend.
.Iadd.10. The surface light source device of claim 8, wherein the
two corner portions of the first and second divisional members are
formed by a drawing process..Iaddend.
.Iadd.11. The surface light source device of claim 8, wherein the
divisional member further includes a third and fourth divisional
member each having a straight shape, wherein the first and second
divisional members are provided on a longitudinal side of the frame
and the third and fourth divisional members are provided on a
lateral side of the frame..Iaddend.
.Iadd.12. A surface light source device, comprising: a light source
section which has a light emitting face; a liquid crystal display
panel which is arranged so as to cover the light emitting face of
the light source section; and a front frame which includes a first
front face portion arranged so as to be provided on a side opposite
the light source section side of the peripheral portion of the
liquid crystal display panel and a first side face portion
extending from an outer periphery of the first front face portion
toward the light source section; a rear frame which includes a
second front face portion arranged so as to be provided on the
light source section side of the peripheral portion of the liquid
crystal display panel and a second side face portion extending from
an outer periphery of the second front face portion toward the
light source section, wherein each of the front frame and the rear
frame is respectively composed of a plurality of divisional members
respectively dividing the front and rear frames in a direction
along the peripheral portion of the liquid crystal display panel,
which have a slit between each divisional member, and a light
shielding portion is provided, at said slit in each of the first
front face portion of the front frame and the second front face
portion of the rear frame, for preventing light of the light source
section from leaking through said slit, wherein the plurality of
divisional members are connected by welding, and the light
shielding portion is formed of a welded portion formed by the
welding, wherein the divisional members for the front frame include
a first and second divisional member each having two corner
portions that include two outside corner portions at an outermost
edge of the divisional member and wherein each of the two outside
corner portions respectively extend around two corners of a
peripheral edge portion of the liquid crystal display panel,
wherein the light shielding portion provided in said slit is
arranged in an entire region in a widthwise direction across the
first front face portion of the front frame and the second front
face portion of the rear frame, and wherein the rear frame slits
are offset relative to the front frame slits in a longitudinal
direction of the divisional members to further prevent light of the
light source section from leaking through the front frame
slits..Iaddend.
.Iadd.13. The surface light source device of claim 12, wherein the
two corner portions of the first and second divisional members are
formed by a drawing process..Iaddend.
.Iadd.14. The surface light source device of claim 12, wherein the
welded portion is formed at each slit between the plural divisional
members in the first and second side face portions, in addition to
each slit between the plural divisional members in the first and
second front face portions..Iaddend.
.Iadd.15. The surface light source device of claim 12, wherein the
divisional member for the front frame further includes a third and
fourth divisional member each having a straight shape, wherein the
first and second divisional members are provided on a longitudinal
side of the front frame and the third and fourth divisional members
are provided on a lateral side of the front frame..Iaddend.
.Iadd.16. A liquid crystal display device, comprising a surface
light source device according to any one of claims 8 and 12,
wherein the liquid crystal display panel includes a pair of
transparent substrates and a liquid crystal layer disposed between
the pair of transparent substrates, and the light source section
serves as a backlight section for emitting light to the liquid
crystal display panel..Iaddend.
Description
CROSS REFERENCE TO RELATED APPLICATIONS
This Non-provisional application claims priority under 35 U.S.C.
.sctn. 119(a) on Patent Application No. 2003-318683 filed in Japan
on Sep. 10, 2003, and No. 2004-239881 filed in Japan on Aug. 19,
2004, the entire contents of which are hereby incorporated by
reference.
BACKGROUND ART
The present invention relates to a surface light source device in
which a frame is arranged along the peripheral portion of a light
emitting face of a light source section, such as a liquid crystal
display device including a backlight section as a light source
section at a back face of a liquid crystal display panel, and
particularly relates to improvement in the frame thereof.
In general, in a liquid crystal display device including a
backlight section at the back face of a liquid crystal display
panel, the liquid crystal display panel is mounted at a frame of
the backlight section and a bezel (rim) is arranged on the
peripheral portion of the liquid crystal display panel for
reinforcing the liquid crystal display panel mounted and for
protecting the peripheral portion of the liquid crystal display
panel.
Meanwhile, upsizing of liquid crystal display devices used in
liquid crystal television sets is recently being promoted. In
association therewith, higher strength is demanded. While, the rim
portion of the bezel is required to be narrowed. Therefore, it is
difficult to increase the strength by widening the rim portion of
the bezel.
To tackling this problem, Japanese Patent Application Laid Open
Publication No. 2000-75273A discloses that the strength of the
casing is increased without inviting increase in thickness thereof,
which shall accompany widening of the peripheral portion of the
bezel, by arranging a flame of an L shape in section having an
opening at a part corresponding to a display region of a liquid
crystal display panel between a back frame of a backlight section
and the liquid crystal display panel.
Also, Japanese Patent Application Laid Open Publication No.
2003-50549A discloses that such a frame is composed of a plurality
of divisional members obtained in such a manner that the members is
cut out from a metal plate, bent into an L shape, and then,
connected with each other by using a L-shaped metal fitting so that
waste part of the metal plate is lessened and the strength of the
frame is increased though the frame is composed of the plural
divisional members, compared with the case where the frame is
merely cut out from a metal plate.
Moreover, Japanese Patent Application Laid Open Publication No.
2001-249619A discloses that in the case where a frame of an L shape
in section used in a liquid crystal display device is composed of a
plurality of divisional members, each connected end portions of the
plural divisional members of the frame are welded in the side face
portion of the frame.
However, in the above conventional cases, small slits are liable to
be formed at the connected portions between the divisional members
in the front face portion of the frame, and light of the light
source section leaks through the slits.
SUMMARY OF THE INVENTION
The present invention has been made in view of the above matter and
has its main object of preventing, in a surface light source device
such as a liquid crystal display device in which a frame composed
of a plurality of divisional members connected is arranged along
the peripheral portion of a light emitting face of a backlight
section as a light source section arranged at the back side of a
liquid crystal display panel as an optical panel, light of the
light source section from leaking through slits between the
divisional members in the front face portion of the frame.
To attain the above object, in the present invention, the at least
one frame having a front face portion arranged so as to cover the
peripheral portion of the light emitting face of the light source
section and a side face portion extending from the outer periphery
of the front face portion toward the light source section is
composed of the divisional members connected with each other, and a
light shielding portion is provided at each slit between the
divisional members in the front face portion of the at least one
frame, whereby the light shielding portion prevents light of the
light source section from leaking through each slit.
Specifically, the surface light source device according to the
present invention includes the light source section, the optical
panel and the at least one frame. The light source section includes
a light emitting face, and the optical panel is arranged so as to
cover the light emitting face of the light source section. The
optical panel performs a predetermined optical operation for light
from the light source section. The at least one frame is arranged
along a peripheral portion of the light emitting face of the light
source section. The at least one frame includes a front face
portion that covers the peripheral portion of the light emitting
face of the light source section and a side face portion extending
from the outer periphery of the front face portion toward the light
source section, and a plurality of divisional members which are
divided in a direction along the peripheral portions of the light
emitting face of the light source section are connected with each
other so as to compose the at least one frame.
At each slit between the divisional members in the front face
portion of the at least one frame, a light shielding portion for
preventing light of the light source section from leaking through
the slit is provided.
It is noted that the above at least one frame may be a rear frame
of which front face portion is located on the light source section
side of the peripheral portion of the optical panel, may be a front
frame of which front face portion is located on the side opposite
the light source section side of the peripheral portion of the
optical panel, or may include both the frames. Further, in the case
where the rear frame and the front frame are provided, it is
possible that the respective light shielding portions of the rear
frame and the respective light shielding portions of the front
frame may be arranged so as not to overlap or so as to overlap with
each other in the thickness direction of the optical panel.
Moreover, it is preferable that the divisional members are
connected by welding and each welded portion formed by the welding
serves as the light shielding portion. Further, in the welding, if
at least part of each slit between the divisional members in the
side face portion is welded in addition to the welding of each slit
between the divisional members in the front face portion, the
torsional strength of the frame is increased in combination with
the welding of the front face portion.
In addition, the above construction is applicable to a liquid
crystal display device including a liquid crystal display panel
having a pair of transparent substrates and a liquid crystal layer
interposed between the pair of transparent substrates as the
aforementioned optical panel. In this case, the light source
section functions as the backlight section for the liquid crystal
display panel.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is an exploded perspective view schematically showing a
whole construction of a liquid crystal display device according to
an embodiment of the present invention.
FIG. 2 is a front view schematically showing the whole construction
of the liquid crystal display device.
FIG. 3 is an enlarged section taken along the line III-III in FIG.
2.
FIG. 4 is an enlarged section taken along the line IV-IV in FIG.
2.
FIG. 5 is a perspective view showing an arrangement of driver
circuits in the liquid crystal display device.
FIG. 6 is a front view schematically showing the liquid crystal
display device of which bezel is taken away.
FIG. 7 is an enlarged section taken along the line VII-VII in FIG.
2.
FIG. 8 is a front view schematically showing Modified Example 1 of
the present embodiment.
FIG. 9 is an enlarged section schematically showing Modified
Example 2 in the present embodiment.
DETAILED DESCRIPTION OF THE INVENTION
An embodiment of the present invention will be described below with
reference to drawings.
FIG. 1 of an exploded perspective view and FIG. 2 of a front view
show schematically the whole construction of a liquid crystal
display device according to the embodiment of the present
invention, wherein the liquid crystal display device is used as a
display device for a 37-inch wide liquid crystal television set of
which height to width ratio of the display screen is 9:16.
As shown in FIG. 3, which is an enlarged section taken along the
line III-III in FIG. 2, and FIG. 4, which is an enlarged section
taken along the line IV-IV in FIG. 2, the liquid crystal display
device includes: a backlight section 10 as a light source section
having a rectangular light emitting face 10a; a liquid crystal
display panel 20 as an optical panel arranged so as to cover the
light emitting face 10a of the backlight section 10; a mounting
frame 30 as a rear frame for fixing the liquid crystal display
panel 20 to the backlight section 10; and a bezel 40 as a front
frame for holding, with the use of the mounting frame 30, the
peripheral portion of the liquid crystal display panel 20 in the
direction of the thickness of the panel (the vertical direction in
FIG. 3 and the transverse direction in FIG. 4).
The backlight section 10 of direct backlight type includes a back
frame 11 of a rectangular shape in section, and a rectangular
opening in which a light emitting face 10a of the backlight section
10 is formed is formed on the liquid crystal display panel 20 side
of the back frame 11. In the peripheral side portion of the back
frame 11, a mounting flange 11a protruding outward is provided at
each central portion in the long side direction of the long side
portions and each end portion in the short side direction of the
short side portions. Inside of the peripheral side portion of the
back frame 11, a support plate 12 is arranged so as to serve as a
bottom portion for the back frame 11. A reflection sheet 13 is
arranged on the support plate 12 and a plurality of line light
sources such as cold-cathode tubes (not shown) are arranged in
parallel on the reflection sheet 13.
The liquid crystal display panel 20 is, for example, of active
matrix type composed of a TFT substrate as a transparent substrate
in which a pixel electrode portion and a TFT (Thin Film Transistor)
are provided for each pixel, a CF substrate as a transparent
substrate in which a counter electrode portion and a color filter
layer are provided, and a liquid crystal layer interposed between
the substrates, and polarizing plates are attached respectively to
the surfaces of the electrode substrates opposite the respective
surfaces on the liquid crystal layer side. In the liquid crystal
display panel 20, data lines for transmitting a data signal to the
source electrode of each TFT are extended in the short side
direction and arranged along the long side direction, and scan
lines for transmitting a scan signal to the gate electrode of each
TFT are extended in the long side direction and arranged along the
short side direction. Correspondingly, as schematically shown in
FIG. 5 of the perspective view, a data driver circuit 25 for
outputting the data signal to each TFT is provided so as to extend
substantially over the entire range on one of the long sides of the
liquid crystal display panel 20, and a scan driver circuit 26 for
outputting the scan singal to each TFT is provided collectively at
each substantial center on the short sides of the liquid crystal
display panel 20. These driver circuits 25, 26 are arranged between
the mounting frame 30 and the bezel 40. The data driver circuit 25
is arranged over the length substantially the same as that of the
long sides along one of long sides of the liquid crystal display
panel 20 so that the distances to the pixel electrode portions on
the same scan line become minimum and equal to one another.
The mounting frame 30 is, as shown in FIG. 3 and FIG. 4,
substantially in an L shape in section including a front face
portion 30a that covers the peripheral portion of the light
emitting face 10a of the backlight section 10 and a side face
portion 30b extending from the outer periphery of the front face
portion 30a toward the backlight section 10 (downward in FIG. 3 and
rightward in FIG. 4). The front face portion 30a is located on the
backlight section 10 side of the peripheral portion of the liquid
crystal display panel 20, the side end portion of the side face
portion 30b (lower side end portion in FIG. 3 and right side end
portion in FIG. 4) is arranged so as to cover at least a part on
the liquid crystal display panel 20 side of the side peripheral
portion of the back frame 11 of the backlight section 10 (upper
side end portion in FIG. 3 and left side end portion in FIG. 4)
from the outside, and the mounting frame 30 is fixed at the side
face portion 30b thereof to the back frame 11. Further, the
mounting frame 30 supports the peripheral portion of the liquid
crystal display panel 20 from the backlight section 10 side with
intervening a cushion material 51 disposed at the liquid crystal
display panel 20 side of the front face portion 30a (upper side in
FIG. 3 and left side in FIG. 4).
Furthermore, the mounting frame 30 is, as schematically shown in
FIG. 6 of the front view, composed of two straight members 31 as
divisional members each forming a straight portion except each end
portion of the short side portions and two U-shaped members 32 as
divisional members each formed of the long side portion and the end
portions of the short side portions at respective end portions of
the long side portion, wherein the respective end portions of the
straight members 31 are connected with the respective end portions
of the U-shaped members 32. Each of the straight members 31 and the
U-shaped members 32 are made by bending a plate piece cut out into
a predetermined shaped from a metal plate (e.g., an iron plate of
about 1.6 mm in thickness), though not shown.
Similar to the mounting frame 30, the bezel 40 is substantially in
an L shape in section including a front face portion 40a that
covers the peripheral portion of the light emitting face 10a of the
backlight section 10 and a side face portion 40b extending from the
outer periphery of the front face portion 40a toward the backlight
section 10, and the side face portion 40b is arrange so as to cover
substantially the entirety of the side face portion 30b of the
mounting frame 30 sideways (see FIG. 3 and FIG. 4). Wherein, the
front face portion 40a is arranged at the side of the peripheral
portion of the liquid crystal display panel 20, which is the
opposite side to the front face portion 30a of the mounting frame
30 (upper side in FIG. 3 and lift side in FIG. 4), so that the
bezel 40 holds, with the use of the front face portion 30a of the
mounting frame 30, the peripheral portion of the liquid crystal
display panel 20 with intervening a cushion material 52 disposed at
the liquid crystal display panel 20 side of the front face portion
40a (lower side in FIG. 3 and right side in FIG. 4).
The front face portion 40a of the bezel 40 is fixed to the front
face portion 30a of the mounting frame 30 by means of a plurality
of screws 60. Mounting flanges 40c protruding outward are provided
at the respective central portions in the long side direction of
the respective long sides (the central portions in the transverse
direction in FIG. 4) and each end portion of the respective short
sides (both ends in the vertical direction in FIG. 3) in the side
face portion 40b of the bezel 40 so as to correspond to the
mounting flanges 11a of the back frame 11, respectively, and the
mounting flanges 40c are fixed to the mounting flanges 11a of the
back frame 11, respectively, by means of a plurality of screws 60.
Whereby, the bezel 40 is mounted to the mounting frame 30 and the
back frame 11.
Furthermore, similar to the mounting frame 30, the bezel 40 is
composed of two straight members 41 as divisional members each
forming a straight portion except each end portion of the short
side portions and two U-shaped members 42 as divisional members
each formed of the long side portion and the end portions of the
short side portions at respective end portions of the long side
portions, wherein the respective end portions of the straight
members 41 are connected with the respective end portions of the
U-shaped members 42 (see FIG. 2). Similar to the mounting framed
30, each of the straight members 41 and the U-shaped members 42 is
formed by bending a plate piece cut out into a predetermined shape
from a metal plate (e.g., an aluminum alloy plate of about 1.6 mm
in thickness).
In the case where either one of the mounting frame 30 and the bezel
40 is formed of a single piece cut out into a predetermined shape
from a metal plate, waste part after cutting out of the metal plate
is increased in association with upsizing of the display region of
a liquid crystal display device. While, in the present embodiment,
both the mounting frame 30 and the bezel 40 are prepared by
connecting the straight members 31, 41 and the U-shaped members 32,
42, each of which is obtained by bending a plate piece cut out from
a metal plate and connecting them with each other, and accordingly,
such waste part can be minimized. It is note that it is taken into
consideration, as can be understood from FIG. 5, that each dividing
point of the mounting frame 30 and the bezel 40 is located so as
not to overlap with the data driver circuit 25 and the scan driver
circuits 26 for the liquid crystal display panel 20. In each
U-shaped member 32, 42 of the mounting frame 30 and the bezel 40,
it is suitable that the corner portions, which are the joint
portions of the end portions of the short sides and the end
portions of the long sides, are formed by drawing so as to form no
connection portions between the front face portions 30a, 40a and
between the side face portions 30b, 40b.
In the present embodiment, as indicated in FIG. 7, an enlarged
section taken along the line VII-VII in FIG. 2, the straight
members 31 and the U-shaped members 32, which form the mounting
frame 30, are connected by welding slits between the straight
members 31 and the U-shape members 32 in the front face portion 30a
of the mounting frame 30 in the entire region in the widthwise
direction of the front face portion 30a, and each welded portions S
formed by the welding serves as a light shielding portions in the
present invention.
Further, in the slits between the straight members 31 and the
U-shape members 32 of the mounting frame 30, in addition to the
front face portions 30a, the side face portions 30b are welded over
the entire region in the widthwise direction thereof, to form
welded portions S.
Referring to the bezel 40, also, slits between the straight members
41 and the U-shaped members 42 in the front face portion 40a and
slits between the straight members 41 and the U-shape members 42 in
the side face portion 40b are welded over the respective entire
regions in the respective widthwise directions, to form welded
portions S (See FIG. 7), similar to the mounting frame 30. It
should be noted that an arc welding may be employed as one example
of the welding method but no limitation is imposed specifically
only if no light leaks through the welded portions S.
Thus, according to the present embodiment, the liquid crystal
display device includes: the backlight section 10 which has the
light emitting face 10a; the liquid crystal display panel 20 which
is arranged so as to cover the light emitting face 10a of the
backlight section 10 and capable of changing the transmittance of
light from the backlight section 10 in each pixel; the mounting
frame 30 which has the front face portion 30a that covers the
peripheral portion of the light emitting face 10a of the backlight
section 10 at the backlight section 10 side of the liquid crystal
display panel 20, and the side face portion 30b extending from the
outer periphery of the front face portion 30a toward the backlight
section 10, and which is arranged along the peripheral portion of
the light emitting face 10a of the backlight section 10; and the
bezel 40 which has the front face portion 40a that covers the
peripheral portion of the light emitting face 10a of the backlight
section 10 at the side opposite the backlight section 10 side of
the peripheral portion of the liquid crystal display panel 20 and
the side face portion 40b extending from the outer periphery of the
front face part 40a toward the backlight section 10, and which is
arranged along the peripheral portion of the light emitting face
10a of the backlight section 10, wherein each of the mounting frame
30 and the bezel 40 is formed in a manner that the two straight
members 31, 41 and the two U-shaped members 32, 42 are respectively
connected with each other by welding the respective entire regions
of the slits in the front face portions 30a, 40a and the respective
entire regions of the slits in the side face portions 30b, 40b.
Whereby light from the backlight section 10 is prevented from
leaking through each slit between the straight members 31, 41 and
the U-shaped members 32, 42 in the front face portions 30a, 40a and
each slit between straight members 31, 41 and the U-shaped members
32, 42 in the side face portions 30b, 40b of the mounting fame 30
and the bezel 40.
Further, each of the straight members 31, 41 and the U-shape
members 32, 42 of the mounting frame 30 and the bezel 40 are
connected not only by welding each slit in the front face portions
30a, 40a but also by welding each slit of the side face portions
30b, 40 b, and therefore, the torsional strength of the mounting
frame 30 and the bezel 40 can be increased, compared with the case
where only each slit in the front face portions 30a, 40a is
welded.
It is noted that the respective sections of the mounting frame 30
and the bezel 40 are substantially in an L shape in the above
embodiment, but may be designed optionally according to needs.
Further, the mounting frame 30 and the bezel 40 are each divided
into the two straight members 31, 41 and the two U-shaped members
32, 42 in the above embodiment, but the number of division and the
shapes of the divisional members may be set optionally. In detail,
for example, the mounting frame 30 (or the bezel 40) may be divided
into two shorter straight members 33 (43) and two longer straight
members 34 (44) as in Modified Example 1 shown in FIG. 8 of the
front view.
Furthermore, the entire regions in the respective widthwise
directions of the slits between the straight members 31, 41 and the
U-shaped members 32, 42 in the side face portions 30b, 40b of the
mounting frame 30 and the bezel 40 are welded in the above
embodiment, but only part thereof may be welded.
Moreover, both the mounting frame 30 and the bezel 40 are composed
of the plural divisional members connected with each other in the
above embodiment, but either one of the mounting frame 30 and the
bezel 40 may be composed of the plural divisional members connected
with each other.
Further, the members are connected by welding and each welded
potions serves as the light shielding portion S in the above
embodiment, but the members may be connected by known connection
means other than welding, or it is possible that the members are
connected by an exclusive connecting method and known shielding
means other than welding may be employed as the light shielding
portions.
Furthermore, each end potion of the divisional members of the
mounting frame 30 and the bezel 40 is formed in a shape having an
end face cut by a plane intersecting with the dividing direction at
a right angle in the above embodiment, but it is possible, as shown
in Modified Example 2 of FIG. 9, which corresponds to FIG. 7, that:
one of the end portions is formed in a step-like shape of which
part on the light source section side is cut off in the panel
thickness direction by a predetermined length L in the dividing
direction (side-ways in FIG. 9); the other end portion is formed in
a step-like shape of which part on the side opposite the light
source section side is cut off in the panel thickness direction;
the end portions are overlaid with each other so as to fill up the
respective cut off portions; and then, the end portions facing with
each other in the dividing direction are welded. In this case, in
order to obtain sufficient strength at the overlaid portions, it is
preferable to set the thicknesses t1, t2 of the overlaid portions
at the end portions to be substantially equal to each other
(t1.apprxeq.t2), and the length L of the overlaid portions is
preferably about 2 mm.
Moreover, the mounting frame 30 and the bezel 40 are made of metal
materials such as an iron plate, an aluminum alloy plate, in the
above embodiment, but may be made of nonmetallic materials only if
they are capable of being welded.
Further, the case where each substrate includes the electrode
portion is referred to in the above embodiment, but the present
invention is applicable to various types of liquid crystal display
devices such as IPS (In Plane Switching) type liquid crystal
display devices in which only one of substrates includes an
electrode portion.
Furthermore, the liquid crystal display device including the
backlight section 10 of direct backlight type in which the line
light source is disposed immediately below the liquid crystal
display panel 20 is referred to in the above embodiment, but the
backlight section 10 is not limited thereto and may be, for
example, of edge lighting type in which a line light source is
located on the side edge of the display region of the liquid
crystal display panel 20.
In addition, the liquid crystal display device is exemplified in
the above embodiment, but the present invention is, of course,
applicable to other types of surface light source devices.
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