Liquid crystal cells – elements and systems – Nominal manufacturing methods or post manufacturing... – Injecting liquid crystal
Reexamination Certificate
1999-11-11
2001-10-16
Sikes, William L. (Department: 2871)
Liquid crystal cells, elements and systems
Nominal manufacturing methods or post manufacturing...
Injecting liquid crystal
C349S187000, C349S191000
Reexamination Certificate
active
06304311
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Technical Field of the Invention
The present invention relates to a method of manufacturing liquid crystal display devices that are used for the image display panel of a personal computer or a television.
2. Description of Prior Art
A conventional method of manufacturing liquid crystal display device is described below with reference to
FIGS. 3
to
5
A liquid crystal display device is constructed as shown in
FIG. 3
such that two opposite and spaced substrates, a lower substrate
11
and an upper substrate
12
, both being made of a light-transmissive material, are affixed to each other with a UV-curable, photo-polymer adhesive
13
, with a liquid crystal material
15
filled in a space between the substrates. The adhesive
13
contains spacers
14
having a 5 &mgr;m diameter for keeping the distance between the lower substrate
11
and the upper substrate
12
constant.
In order to dispose the liquid crystal material
15
inside of the adhesive
13
as shown in
FIG. 3
, one conventional liquid crystal drop method comprises the steps of applying the adhesive
13
on the lower substrate
11
to a thickness of 30 &mgr;m at the perimeter (FIG.
4
A), dropping the liquid crystal material
15
to an inner side relative to the adhesive
13
(FIG.
4
B), superposing the upper substrate
12
above the lower substrate
11
and pressing the substrates until the gap between both substrates becomes 5 &mgr;m (FIG.
4
C), and curing the adhesive
13
by irradiating ultraviolet light, whereby the liquid crystal display device is completed (FIG.
4
D).
The process of affixing the two substrates together in the above conventional method will be described in more detail with reference to
FIGS. 5A through 5F
.
First, a lower substrate
11
, on which an adhesive
13
of UV-curable photo-polymer has been applied to a thickness of 30 &mgr;m at the perimeter, after which the resulting cavity has been filled with a liquid crystal material
15
, is placed on a table
17
movable in a horizontal direction, and the entire lower surface of the substrate
11
is fixedly held by vacuum suction with a suction-holding mechanism
18
(FIG.
5
A). Next, an upper substrate
12
is positioned at a distance opposite the lower substrate
11
and the entire upper surface of the substrate
12
is fixedly held by vacuum suction with a suction-holding mechanism
19
(FIG.
5
B). The upper substrate
12
is then lowered so that the distance between the upper substrate
12
and the lower substrate
11
is 1 mm, and the vacuum chamber C is closed (FIG.
5
C). Next, the table
17
on which the lower substrate
11
is placed is moved in a horizontal direction for adjusting the positional relationship between the upper substrate
12
and the lower substrate
11
, and a vacuum is drawn within the vacuum chamber C (FIG.
5
D). The upper substrate
12
is then lowered so that it contacts the adhesive
13
or the liquid crystal material
15
and is further pressed thereon until the distance between the upper and lower substrates becomes 5 &mgr;m, whereby the upper substrate
12
is affixed to the lower substrate
11
through the adhesive
13
(FIG.
5
E). After that, ultraviolet rays
16
are irradiated for curing the adhesive
13
(FIG.
5
F), by which the affixing of upper and lower substrates is completed.
In the above described conventional method, after the positions of the upper substrate
12
and the lower substrate
11
are adjusted relative to each other with the
1
mm spacing therebetween, the upper substrate
12
is lowered nearly 1 mm to contact the adhesive
13
and the liquid crystal material
15
, and is further pressed in a vertical direction. There was thus the problem that the upper substrate
12
is sometimes misaligned relative to the lower substrate
11
during the period in which it is lowered toward and pressed onto the lower substrate
11
.
SUMMARY OF THE INVENTION
In view of the above described problem in the prior art method, an object of the present invention is to provide a method of manufacturing liquid crystal display devices with which misalignment between an upper and lower substrates when affixing them together is substantially prevented, whereby defects in resulting display panels such as unevenness in image can be eliminated.
To accomplish the above object, the present invention provides a method of manufacturing a liquid crystal display device comprising the steps of positioning a first substrate on which an adhesive has been applied and a liquid crystal material has been deposited within a vacuum chamber and holding a lower surface of the first substrate fixedly by vacuum suction; a second substrate of which an upper surface is held fixedly by vacuum suction is brought opposite to the first substrate at a predetermined distance therefrom; moving one or both of the first and second substrates closer to each other for bringing the second substrate into contact with the adhesive or the liquid crystal material on the first substrate; moving both of the first and second substrates relative to each other in a direction parallel to the substrate surface for position alignment; and moving one or both of the first and second substrates for pressing the substrates to each other, whereby both substrates are affixed together.
In this method, since the position alignment of the first and second substrates is performed after the second substrate has been brought into contact with the adhesive or the liquid crystal material on the first substrate, both substrates need to be moved only a small distance when adjusting their positions relative to each other, whereby the two substrates are hardly misaligned relative to each other when they are affixed together. Defects such as unevenness in an image displayed on a resulting display panel can be accordingly eliminated.
The present invention also provides a method of manufacturing a liquid crystal display device comprising the steps of positioning a first substrate on which an adhesive has been applied and a liquid crystal material has been deposited within a vacuum chamber and holding a lower surface of the first substrate fixedly by vacuum suction; a second substrate of which an upper surface is held fixedly by vacuum suction is brought opposite to the first substrate at a predetermined distance therefrom; moving one or both of the first and second substrates closer to each other until they are located at a predetermined spacing; moving both of the first and second substrates relative to each other in a direction parallel to the substrate surface for preliminary position alignment; moving one or both of the first and second substrates closer to each other for bringing the second substrate into contact with the adhesive or the liquid crystal material on the first substrate; moving both of the first and second substrates relative to each other in a direction parallel to the substrate surface for position alignment; and moving one or both of the first and second substrates for pressing the substrates to each other, whereby both substrates are affixed together.
Misalignment between both substrates when affixing them together can be prevented and defects such as unevenness in image displayed on a resulting display panel can be accordingly eliminated, too, with this method. Moreover, since the substrates need to be moved only a small distance when adjusting their positions relative to each other owing to the preliminary positional alignment, the melting-in of the adhesive into the liquid crystal material can be suppressed.
If, in the step of bringing the second substrate into contact with the adhesive or the liquid crystal material on the first substrate, the second substrate is positioned at a height so that a minute gap is created between the second substrate and the adhesive on the first substrate, it is prevented that both surfaces are stuck together with the adhesive before the position alignment.
If a resilient member is interposed between the first substrate and a mechanism for holding the first substrate by vacuum suctio
Egami Norihiko
Hokazono Nobutaka
Inoue Susumu
Matsukawa Hideki
Sakai Naoto
Chowdhury Tarifur R.
Matsushita Electric - Industrial Co., Ltd.
Price and Gess
Sikes William L.
LandOfFree
Method of manufacturing liquid crystal display device does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Method of manufacturing liquid crystal display device, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Method of manufacturing liquid crystal display device will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2575440