Liquid crystal cells – elements and systems – Particular structure – Holder – support – frame – or housing
Reexamination Certificate
2000-07-10
2003-08-26
Ton, Toan (Department: 2871)
Liquid crystal cells, elements and systems
Particular structure
Holder, support, frame, or housing
C349S059000
Reexamination Certificate
active
06611302
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a flat panel display device such as a liquid crystal display device and, more particularly, to a structure of supporting a flat display panel.
2. Description of the Prior Art
In recent years, as a device is becoming smaller, lighter, and thinner, a flat panel type electron display device (hereinbelow, called a flat panel display device) typified by a liquid crystal display device for use in various devices is also becoming thinner. The structure of supporting the flat display panel is also devised accordingly.
A conventional example of a liquid crystal display device having a backlight will be described herein below as an example of the flat panel display device.
As shown in
FIG. 1
, a conventional liquid crystal display device
1
comprises a rectangular liquid crystal panel
2
and a rectangular light guide plate
3
for backlight provided on the under face side of the liquid crystal panel
2
. The liquid crystal panel
2
comprises substrate members
4
and
5
such as a pair of glass substrates, which are opposed to each other. Outer surfaces of the substrates
4
and
5
are provided with polarizers
6
. The lower substrate
4
is provided with a matrix array of thin film transistors and thus which is called a TFT substrate to have a shutter function of controlling light from the light guide plate
3
. The upper substrate
5
is provided with color filters (CF) of three primary colors for color display and thus which is called a CF substrate.
The liquid crystal panel
2
and the light guide plate
3
are laminated together with an inner holding frame
11
inserted therebetween. This laminated structure is housed in a container formed with a pair of outer holding frames
16
and
17
. Each of the inner frame
11
and the outer frames
16
and
17
is made of a synthetic resin and formed in a rectangular frame shape.
On the inner holding frame
11
, a holding wall
15
is formed in the circumferential direction. The liquid crystal panel
2
is disposed within the holding wall
15
such that end surfaces of the liquid crystal panel
2
are opposed to a holding face
15
a
of the holding wall
15
.
A holding recess
12
is formed in the lower part of the inner holding frame
11
. The light guide plate
3
is fit and held in the recess
12
. The inner holding frame
11
is provided with a supporting portion or a spacer
13
so as to be interposed in the circumferential direction between the light guide plate
3
and the liquid crystal panel
2
. The liquid crystal panel
2
is disposed over the light guide plate
3
via the spacer
13
in a state where the lower substrate
4
is in contact with the spacer
13
.
As described above, the outer frames
16
and
17
as upper and lower holding fittings each of which is a frame member having an L shape in cross section are fit to the upper and lower parts of the inner holding frame
11
which holds the liquid crystal panel
2
and the light guide plate
3
. By fitting the outer frames
16
and
17
, the light guide plate
3
and the liquid crystal panel
2
are integrated with the inner holding frame
11
. In such a manner, a liquid crystal display module is obtained.
Such a liquid crystal display module is attached to a casing for display of an information processor.
As shown in
FIGS. 2A and 2B
, the liquid crystal panel
2
is generally constructed so that two sides in the CF substrate
5
are arranged on the inner side from the end faces of the TFT substrate
4
to expose electrode terminals (not shown) provided along two sides which are orthogonal to each other in the TFT substrate
4
. As shown in
FIG. 2C
, printed circuit boards
23
on which semiconductor ICs for control are mounted and the electrode terminals of the TFT substrate
4
are electrically connected via TCPs (Tape Carrier Packages)
24
.
Such a liquid crystal display panel
2
is produced as follows. As shown in
FIG. 3A
, a panel
2
a
is prepared by adhering the substrates
4
and
5
having the same outer shapes. Along a predetermined shape (indicated by an alternately long and short dash line
41
in FIG.
3
A), as shown in
FIG. 3B
, a cutting groove
201
is formed in the TFT substrate
4
by a deep penetrating cutter
21
. After that, the panel
2
a
is turned upside down. A predetermined impact is applied to the panel
2
a
on the side opposite to the cutting groove
201
side by a hammer, thereby breaking only the TFT substrate
4
.
Subsequently, as shown in
FIG. 3C
, a cutting groove is similarly formed in the CF substrate
5
by the deep penetrating cutter
21
along a predetermined shape (indicated by an alternate long and two short dashes line
51
in FIG.
3
C). After that, the panel
2
a
is turned upside down and a predetermined impact is applied to the side opposite to the cutting groove side by a hammer, thereby breaking only the CF substrate
5
.
In such a manner, as shown in
FIG. 2A
, the liquid crystal panel
2
made by the substrates
4
and
5
formed in the predetermined shapes is obtained.
As shown in
FIG. 2B
, the liquid crystal panel
2
obtained by cutting the outer sides is chamfered by polishing the corners on the surface and back face of the cut faces. In one of the sides in the longitudinal direction and one of the sides in the width direction having electrodes to which the TCPs
24
are connected, the corners on the surface side adhered to the CF substrate
5
of the TFT substrate
4
are also chamfered.
As shown in
FIG. 2C
, the printed circuit boards
23
are connected via the TCPs
24
to one of the sides in the longitudinal direction and one of the sides in the width direction having electrodes of the chamfered liquid crystal panel
2
. After that, the resultant is fit in the holding walls
15
of the holding frame
11
.
In the case of manufacturing the liquid crystal panel
2
by cutting the panel
2
a
in a predetermined outer shape as described above, the substrates
4
and
5
are cut almost in the same outer shape so that the cut faces are flush with each other in each of the other sides in the longitudinal and width directions to which the TCP
24
is not connected. As shown in
FIG. 4
, however, there is a case such that a deviation of about 0.3 mm at the maximum occurs between the TFT substrate
4
and the CF substrate
5
and a sharp edge
501
of the CF substrate
5
is exposed.
Since the deviation of the edge
501
is very small, chamfering cannot be performed. Consequently, the edge
501
has to be enclosed and held as it is in the holding walls
15
of the holding frame
11
.
As shown in
FIGS. 5A and 5B
, when the liquid crystal panel
2
in which a deviation occurs between the TFT substrate
4
and the CF substrate
5
is supported together with the light guide plate
3
by the holding frame
11
to thereby form the liquid crystal display device
1
, on or after attachment of the liquid crystal panel
2
to the holding frame
11
, there is a case such that either the edge
401
of the TFT substrate
4
or the edge
501
of the CF substrate
5
which occurs due to the deviation between the substrates
4
and
5
cuts the holding face
15
a
of the holding wall
15
.
When the holding face
15
a
of the holding wall
15
is cut, the following problem occurs. A dust cut from the holding wall
15
enters between the liquid crystal panel
2
and the light guide plate
3
and partially shields light from the light guide plate
3
and it disturbs display performed by the liquid crystal display device
1
. The problem occurs similarly also in a reflection type liquid crystal display device employing a reflector in place of the light guide plate.
Since the holding frame
11
is provided in the thickness direction by the holding walls
15
so as to surround the liquid crystal panel
2
, there are problems such that a detaching work of the liquid crystal panel
2
for test, maintenance or replacement is difficult and, moreover, it is very troublesome to attach the liquid crystal panel
2
to the holding frame
11
.
Obviously, the pr
Sakaki Yoshinobu
Ueda Shoichi
Akkapeddi P. R.
McGinn & Gibb PLLC
NEC LCD Technologies Ltd.
Ton Toan
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