Semiconductor device manufacturing: process – Making device or circuit emissive of nonelectrical signal – Including integrally formed optical element
Reexamination Certificate
2001-06-18
2003-03-11
Nelms, David (Department: 2818)
Semiconductor device manufacturing: process
Making device or circuit emissive of nonelectrical signal
Including integrally formed optical element
C349S189000, C349S153000, C349S154000, C349S155000
Reexamination Certificate
active
06531329
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a method of manufacturing a liquid crystal display panel used for a display device.
The present application claims priority of Japanese Patent Application No. 2000-85488 filed on Jun. 20, 2000, which is hereby incorporated by reference.
2. Description of the Related Art
A liquid crystal display panel has been heretofore widely used as a display device such as a TV monitor and as a display device for office automation equipment. As a method of manufacturing this liquid crystal display panel, there is known a method in which a sealing material is coated onto a periphery portion of one of a pair of transparent glass substrates, liquid crystal is dropped on this transparent glass substrate, and then the two transparent glass substrates superposed upon another are compressively attached to each other, and a method in which a pair of opposite transparent glass substrates are attached to each other with a gap therebetween, and the gap is sealed after injecting liquid crystal into the gap.
As shown in FIG.
14
A and
FIG. 15
, as a method to drop the liquid crystal, there is a method in which spacers
102
of a thickness t, which serve to regulate a gap between the transparent glass substrates
101
and
106
, are scattered on one transparent glass substrate
101
, on which signal lines and scanning lines (not shown) are arranged in a matrix fashion, and a TFT and a pixel electrode (not shown) are connected to each crossing point of the signal lines and the scanning lines, and a sealing material
103
is coated onto an angular ling portion of a display area having a longitudinal dimension a and a lateral dimension b so that the sealing material
103
surrounds a peripheral portion thereof with a predetermined height h.
Next, as shown in
FIG. 14B
, liquid crystal
104
of a prescribed amount VL is dropped, for example, at a central portion of the display area surrounded by the sealing material
103
. This prescribed amount VL is equal to a volume of a space formed between the transparent glass substrates
101
and
106
at the time when the later-described gap between the transparent glass substrates
101
and
106
becomes a prescribed value, and VL is equal to abt.
Next, as shown in
FIG. 14C
, the transparent glass substrate
101
mounting the liquid crystal
104
is inserted in a vacuum pressure decompression bath
105
, and the other transparent glass substrate
106
in which a common electrode and a color filter (not shown) are arranged is superposed on the transparent glass substrate
101
while keeping a pressure of the vacuum decompression bath
105
at a predetermined pressure p
1
. At this time, residual gas
107
of a volume V
1
occupies a predetermined space.
Subsequently, compressive force is gradually applied to the transparent glass substrates
101
and
106
. AS shown in
FIG. 14D
, the transparent glass substrates
101
and
106
are pressed against each other to be compressively attached until an interval between the transparent glass substrates
101
and
106
becomes the foregoing prescribed value equal to the height t of the spacer
102
. Furthermore, the pressure in the vacuum decompression bath
105
is restored to an atmospheric pressure p
0
, and thus the liquid crystal panel in which the liquid crystal
104
is sealed is obtained. At this time, the residual gas
107
is also compressed and visually recognized as air bubbles of a volume V
2
.
For example, when the prescribed amount VL of the liquid crystal
104
and the volume V
1
of the residual gas
107
are calculated for a 14-inch type liquid crystal display panel, the prescribed amount VL (=abt) is 310.65 mm
3
and the volume V
1
(=abh−VL) is 1553.21 mm
3
, assuming a=216.1 mm, b=287.5 mm, t=0.005 mm, h=0.03 mm, and p
1
=1 Pa.
A volume V
2
(=V
1
p
1
/p
0
) of the residual gas
107
after being compressed is calculated to be 0.015 mm when p
0
=1.013×10
5
Pa. If the shape of the residual gas (air bubble)
107
is assumed to be cylindrical, a cross section S (=V
2
/t) [mm
2
] of the residual gas (air bubble)
107
is 3 mm
2
, and a diameter f thereof is 1.9 mm.
As described above, the residual gas
107
visually recognized in the display area are sealed in the liquid crystal display panel causing a problem that a quality degradation of the liquid crystal display panel is brought about.
Therefore, for example, in Japanese Patent Laid-open No. Sho56-155920 and No. Hei03-255422, disclosed are techniques in which after a sealing material is coated onto a peripheral portion of one of a pair of transparent glass substrates, liquid crystal is dropped onto one of the transparent glass substrates so as to fill a gap between the pair of the transparent glass substrates and air bubbles are ejected from the gap. The techniques disclosed in Japanese Patent Laid-open No. Sho56-155920 and No. Hei03-255422 are hereinafter referred to as a first prior art and a second prior art respectively.
In the first prior art, as shown in
FIG. 16A
, after spacers (not shown) are scattered on a transparent glass substrate
201
, an ultraviolet-curing sealing material
202
is coated onto a peripheral portion of the transparent glass substrate
201
.
Next, as shown in
FIG. 16B
, a liquid crystal
203
is dropped onto the transparent glass substrate
201
, and an other transparent glass substrate
204
facing the transparent glass substrate
201
is superposed thereon. At this time, a quantity of the liquid crystal
203
dropped is set larger than that necessary for displaying.
Subsequently, an ultraviolet ray is radiated onto the sealing material
202
except for a predetermined ejection portion
202
H to cure the sealing material
202
, and both of the transparent glass substrates
201
and
204
are pressed from both sides thereof. The liquid crystal
203
fills a gap between both of the transparent glass substrates
201
and
204
. A surplus amount of the liquid crystal
203
is ejected through the ejection portion
202
H outside the sealing material
202
. Simultaneously, air bubbles are also exhausted.
Then, as shown in
FIG. 16C
, an ultraviolet ray is irradiated onto the ejection portion
202
H of the sealing material
202
to cure it, thus sealing the liquid crystal
203
between the transparent glass substrates
201
and
204
.
In the second prior art, as shown in
FIG. 17A
, after spacers (not shown) are scattered on a transparent glass substrate
301
, a sealing material
302
is coated on a peripheral portion of the transparent glass substrate
301
. At this time, an opening portion
302
H is provided in a part of a coating pattern of the sealing material
302
.
Next, as shown in
FIG. 17B
, a liquid crystal
303
is dropped on the transparent glass substrate
301
, and an other transparent glass substrate
304
facing the transparent glass substrate
301
is superposed thereon. At this time, a quantity of the dropped liquid crystal
303
is set larger than that necessary for displaying.
Both of the transparent glass substrates
301
and
304
are pressed from both sides thereof, and the liquid crystal
303
fills a gap between the transparent glass substrates
301
and
304
. Then, a surplus amount of the liquid crystal
303
is ejected from the opening portion
302
H. At this time, air bubbles are simultaneously exhausted.
Then, as shown in
FIG. 17C
, the sealing material
302
is cured, and the opening portion
302
H is sealed by an adhesive
305
.
However, in the foregoing first and second prior arts, there is a problem that the surplus amounts of the liquid crystal
203
and
303
are needed and expensive liquid crystal material is wasted.
Furthermore, in the first prior art, since the surplus amount of the liquid crystal
203
is exhausted to the outside over the sealing material
202
, there is a problem that the sealing material
202
is also swept away together with the liquid crystal
203
in exhausting the liquid crystal
203
, th
Asakura Tetsuroh
Sasaki Takeshi
Katten Muchin Zavis & Rosenman
Le Thao P.
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