Adhesive bonding and miscellaneous chemical manufacture – Differential fluid etching apparatus – For liquid etchant
Reexamination Certificate
2001-12-27
2003-04-22
Mills, Gregory (Department: 1763)
Adhesive bonding and miscellaneous chemical manufacture
Differential fluid etching apparatus
For liquid etchant
C156S345230
Reexamination Certificate
active
06551443
ABSTRACT:
This application claims the benefit of Korean Patent Application No. 2000-86744 filed on Dec. 30, 2000, which is hereby incorporated by reference as if fully set forth herein.
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a device for etching a glass substrate during fabrication of a liquid crystal display (LCD) device, and in particular, to an apparatus for holding a bubble plate in place in an device.
2. Discussion of the Related Art
An LCD, a plasma display panel (PDP), an electro-luminescent display (ELD) or a vacuum fluorescent display (VFD) are generally used for flat panel display devices. The LCD is one of the most commonly used and active research is being pursued heavily in this area.
Portable televisions and notebook computers employing the LCD are currently on sale. However, several problems still remain unsolved. In particular, reducing the size and weight is a critical task to be solved for portable televisions and notebook computers for the sake of portability.
A variety of methods may be applicable to reduction of weight of the LCD. However, it is difficult to reduce size and weight of other elements constituting the LCD in view of its structure and the current technology. Yet, the possibility still remains to reduce the weight of a glass substrate, which is a basic element of the LCD.
As the glass substrate is one of the largest weight elements among all the elements that make up a LCD, reducing the weight of the LCD can be preferably achieved by reducing the weight of the glass substrate. Here, reducing the weight of the glass substrate means reducing the thickness of the glass substrate.
However, reducing the thickness of the glass substrate leads to damage of the glass substrate. For example, uneven processing of a surface of the glass in the course of fabricating the glass substrate causes a critical fault in the quality of screen of the LCD. Therefore, it is a quite difficult and important task to reduce the thickness of the glass substrate evenly.
The most common method for reducing the thickness of the glass substrate thereby reducing the weight, is to etch the surface of the glass substrate by dipping the glass substrate into etchant confined in a container.
However, there are a number of problems with this method, for example, it fails to produce an evenly etched substrate due to imperfection of the substrate. Moreover, impure materials generated in the etching process stick to the substrate, thereby resulting in an uneven surface of the substrate.
Further, when etching the substrate to be very thin, a loading force on the substrate inherent in the processes of fabricating the LCD can cause a cracking in the substrate due to uneven thickness as a result of this etching method.
FIG. 1
is a block diagram illustrating a structure of a conventional device for etching a glass substrate. Referring to
FIG. 1
, the device comprises an etching section
8000
for etching the substrate, a cleaning section
6000
for removing the etching solution residual from the etched substrates with deionized water (DI), and a drying section
7000
for drying the cleaned substrate.
The etching section
8000
comprises an etcher
1000
, an etching solution recycling section
2000
for storing the etching solution after removing impure materials generated by etching the substrate with the etcher
1000
. Further, a DI supplying section
3000
for supplying DI, a undiluted etching solution supplying section
4000
for supplying a undiluted etching solution, and an etching solution mixing section
5000
for receiving the DI and the undiluted etching solution from the DI supplying section and the undiluted etching solution supplying section
4000
, respectively, and receiving the purified etching solution from the etching solution recycling section
2000
to mix and supply the etching solution to the etcher
1000
.
When performing an etching process by using the device for etching a glass substrate as constructed above, the etching solution inflows to an etching bath of the etcher
1000
from the etching solution mixing section
5000
. If a glass substrate is put into the etching bath, the glass substrate is etched in the etching bath by a reaction between the glass substrate and the etching solution.
The etching solution is then circulated from the etcher
1000
to the etching solution recycling section
2000
and the etching solution mixing section
5000
.
Meanwhile, in the process of etching the glass substrate to fabricate an LCD, a cassette receiving the glass substrate is put into the etching bath
1
filled with Hydrofluoric (HF) acid used to etch the glass substrate. The following is a detailed description of that process.
As shown in
FIGS. 2 and 3
, the conventional device for etching a glass substrate comprises an etching bath
1
filled with HF, an etching solution, a cassette installed within the etching bath
1
for receiving a glass substrate, a plurality of cassette guides
3
installed on a lower portion of the cassette
2
, a plurality of bolts
7
of a Teflon material penetrating the cassette guides
3
and is clamped with the etching bath
1
, and a bubble plate
4
fixed onto the cassette guides
3
and having a plurality of bubble holes
400
for forming bubbles.
A plurality of carrier gas supplying holes
410
are formed on side surfaces of the bubble plate
4
so as to be connected to a nitrogen supplying line (not shown in the drawings).
Two bolts
7
are clamped with each of the cassette guides
3
. Thus, a total of eight bolts
7
are clamped with the cassette guides
3
.
This conventional device for etching a glass substrate has a drawback of changing and cleaning the bubble plate
4
when the bubble plate
4
is blocked by sludge generated during the etching process. When this occurs the bubble plate
4
is changed and cleaned after releasing all of the bolts
7
of a Teflon material and detaching the cassette guides
3
. After the cleaning, the bubble plate
4
is reassembled in a reverse order. This drawback causes a significant delay resulting in higher production costs.
In addition, the conventional device for etching the glass substrate often fails to etch the glass substrate in a high quality manner and is likely to damage the glass substrate. For example, as a result of changing the bubble plate, the bolts
7
supporting the cassette guides
3
can be displaced from their original positions within the etching bath
1
.
Further, when changing the bubble plate
4
, sludge often flows into the clamping holes of the bolts
7
, thereby causing an incomplete clamping. Such a displacement of the cassette guides
3
within the etching bath
1
results in a low-quality etching and a damage of the glass substrate.
In addition, the process of releasing two bolts
7
from each of the cassette guides
3
consumes a long period of time, and subsequently poses a jeopardy to a worker of being exposed to harmful HF for a longer period of time.
SUMMARY OF THE INVENTION
Accordingly, the present invention is directed to an apparatus that substantially obviates one or more of the problems due to the limitations and disadvantages of the related art. It is, therefore, an object of the present invention to provide an apparatus for etching a glass substrate which can prevent low-quality etching and damage of the glass substrate. Ideally an apparatus prevents damage caused by the displacement of the cassette guides, for example, by improving a method of fixing the bubble plate within an etching bath by providing a cylinder so as to facilitate the changing and cleaning process.
To achieve the above object, there is provided an apparatus for etching a glass substrate in fabrication of an LCD, comprising: an etching bath having an etching solution; a plurality of cassette guides on a bottom surface of the etching bath; a cylinder on an external side of the etching bath; a plurality of plungers on the cylinder and the cassette guides; and a bubble plate fixed by the cassette guides.
The apparatus for etching a glass substrate accord
LG.Philips LCD Co. , Ltd.
MacArthur Sylvia R.
McKenna Long & Aldridge LLP
Mills Gregory
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