Electric lamp or space discharge component or device manufacturi – Apparatus – Assembly means
Reexamination Certificate
1999-12-22
2002-06-04
Ramsey, Kenneth J. (Department: 2879)
Electric lamp or space discharge component or device manufacturi
Apparatus
Assembly means
Reexamination Certificate
active
06398610
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a production line for producing a display panel such as a liquid crystal panel and in particular, to a display panel production line including a cutting step area for cutting a glass substrate into a size of display panel, an injection step area for filling the display panel with liquid crystal, and a sealing step area for sealing the liquid crystal injection opening, wherein the panel filled with the liquid crystal is carried in a cassette between the areas.
2. Description of the Related Art
Generally, display panels are used as output display units of electronic apparatuses. Among the display panels, liquid crystal panels are widely used for display of personal computers and word processors because of low power consumption, thin and small weight, and low voltage drive.
As shown in a perspective view and a front view of
FIG. 9
, two glass substrates, i.e., a TFT substrate
1
and a color filter substrate
2
are bonded together via a seal
3
, leaving a gap of 5 to 6 micrometers. This gap is filled with liquid crystal. It should be noted that a liquid crystal injection opening
4
is provided at the lower end of the liquid crystal panel where no seal
3
is provided
In general, such a liquid crystal panel is produced by the steps shown in FIG.
10
. Firstly, a large-area glass substrate is subjected to washing, drying, orientation film printing, rubbing, seal printing, and the like, which will be referred to as a TFT substrate formation step
5
. Thus, a TFT substrate
1
is produced. On the other hand, another large-area glass substrate is subjected to washing, drying, orientation film printing, rubbing, spacer distribution, and the like, which will be referred to as a color filter substrate formation step
6
. Thus, a color filter substrate
2
is produced.
Next, the color filter substrate
2
is superposed on the TFT substrate
1
with a gap, which will be referred to as a superposing step
7
. Thus two glass substrates are bonded to each other.
The large-area glass substrates are cut into a plurality of liquid crystal panels with a size corresponding to type
12
to type
15
, which will be referred to as a cutting step
8
. The cutting is performed by using a diamond cutter to scribe the surface of the TFT substrate
1
and the color filter substrate
2
, after which a shock is applied so as to separate the liquid crystal panels along the scribe. A liquid panel which has been cut out has a configuration as shown in FIG.
9
.
After the cutting step
8
complete, liquid crystal injection step
9
is performed to fill the liquid crystal panel gap with a liquid crystal material. This liquid crystal injection step
9
is performed as follows. Firstly, as shown in
FIG. 11
, a liquid crystal vessel
11
containing a liquid crystal material
10
and a plurality of liquid panels P is placed in a vacuum chamber
12
and the air is discharged from the vacuum chamber
12
. Next, when the pressure in the vacuum chamber
12
has become sufficiently low, the liquid crystal injection opening
4
of the liquid crystal panel is immersed in the liquid crystal material
10
, and then atmospheric air is introduced into the vacuum chamber
12
so as to be under atmospheric pressure. Thus, the gap is filled with the liquid crystal material
10
by the capillary phenomenon and by the pressure difference between the pressure inside the liquid crystal panel and the pressure of the vacuum chamber
12
.
After injection of the liquid crystal material
10
is complete in the liquid crystal injection step
9
, the liquid crystal injection opening
4
is sealed in the sealing step
13
, thus sealing the liquid crystal material
10
. The sealing step
13
includes wiping off, UV resin application, and UV radiation. After this, a polishing step, a polarizing plate attachment step, an inspection step are performed to complete the liquid crystal panel.
It should be noted that in the production line performing the aforementioned steps, a cassette is used for storing and carrying the liquid crystal panel after the cutting step
8
. In general cassettes used have an identical outer configuration, so as to be able to contain various sizes of the liquid crystal panel. If the cassettes have different outer configurations, the automation line may be disturbed. Moreover, in order to carry panels of different sizes, a holding plate as a partition is moved to hold the panel in the cassette.
However, the conventional liquid crystal panel production steps have problems as follows.
These years, for the variety of application fields, a larger liquid crystal panel is required. Moreover, for assuring a wide angle of visibility and for increasing the display speed response, a smaller gap is required. In order to realize a large panel with a smaller gap, the time required for liquid crystal injection per a unit number of panels has greatly increased in comparison to the other steps. For example, the liquid crystal injection step
9
requires 4 or 5 times more than the cutting step
8
and the sealing step
13
. Accordingly, in the liquid crystal panel production line, it is necessary to improve the time efficiency of the liquid crystal injection step
9
.
Here, it can be considered to increase the number of liquid crystal injection apparatuses which are expensive in general or to use a cassette of larger outer configuration to store more panels. However, this may affect the other existing steps and the production line, and not preferable from the viewpoint of costs. Actually, it is necessary to improve the production efficiency of the entire production line.
SUMMARY OF THE INVENTION
It is therefore an object of the present invention provide a display panel production line capable of improving the production line so that a variety of liquid crystal panels including a large-area panel with a reduced gas can be produced in a single production line, even in an automated line using a normalized cassette for the respective steps.
The display panel production line according to the present invention (Claim
1
) comprises: a cutting step area for cutting a glass substrate into a display panel size; an injection step area for injecting liquid crystal into the display panel; and a sealing step area for sealing a liquid crystal injection opening of the display panel which has been filled with the liquid crystal; wherein a predetermined cassette is used as a medium to contain and convey the display panel between the areas, the display panel production line further comprising a relocation area for converting the number of display panels contained in the cassette.
With this configuration, it is possible to process more liquid panels as a processing unit number in the liquid crystal injection step than in the cutting step and the sealing step. Moreover, this configuration can be used without modifying a cassette currently used in the cutting step and the sealing step.
As a result, when it is necessary to increase the processing unit number of the liquid crystal panels in the liquid crystal injection step, considering the variety of the liquid crystal panel types and improvement of the entire production line, the processing unit number can be increased in the relocation step area and when there is not such a need, the production line can be used without the relocation step area.
Accordingly, even when using a conventional production line as it is, there is no need of increasing the number of the liquid crystal injection apparatuses and it is possible to improve the liquid panel production step and the entire production line efficiency without affecting any other existing steps and the production line.
According to another aspect of the invention (Claim
2
), the relocation step area includes a display panel relocation apparatus for relocating panels from a cassette exhausted from the cutting step area, into a cassette to be supplied to the injection step area. In this relocation, more panels are placed in the cassette to be supplied to the injection st
NEC Corporation
Ramsey Kenneth J.
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