Substrate for liquid crystal display element and method for manufacturing liquid crystal display element using the substrate

A liquid crystal display device includes transparent electrodes mutually extending in parallel, and lead patterns used as terminals leading from ends of the transparent electrodes, both formed on a cell substrate produced by separating a large glass substrate. In the device, extension patterns leading from other ends of the transparent electrodes are formed on the cell substrate, and minute gaps for discharging static electricity accumulated in the transparent electrodes during a production process are formed at portions of the extension patterns outside an effective display region. The liquid crystal display device is produced such that transparent electrodes, lead patterns used as terminals leading from ends of the transparent electrodes, extension patterns leading from the other ends of the transparent electrodes, and an identical potential pattern outside the cell substrate-formed patterns being conductive with the transparent electrodes are formed with a plurality of cell substrate-formed regions being adjacently positioned, minute gaps narrower than the gap between the adjacent transparent electrodes are formed within each cell substrate-formed region outside an effective display region, and the large glass substrate is cut so that a plurality of cell substrates are separately formed.

BACKGROUND OF THE INVENTION 
1. Field of the Invention 
The present invention relates to a liquid crystal display device formed so 
that electrostatic destruction of each transparent electrode can be 
prevented and quality inspection of the device can be performed with a 
pattern checker, and a method for producing the liquid crystal display 
device. 
2. Description of the Related Art 
In general, a plurality of cell substrates for a liquid crystal display 
device are simultaneously, separately formed by cutting a large glass 
substrate provided with transparent electrodes, an orientation film, and 
so forth. If a large amount of static electricity accumulates when the 
cell substrates are rubbed during an orientation process, discharge occurs 
between adjacent transparent electrodes, which may result in inferior 
display due to damage to both the transparent electrodes and the 
orientation films by arc heat. Accordingly, when the cell electrodes are 
produced, prevention of electrostatic destruction is widely employed, in 
which the static electricity accumulated in the transparent electrodes can 
be removed to an identical potential pattern conductive to the transparent 
electrodes via lead patterns, which is previously formed outside a cell 
substrate-formed region on the large glass substrate. 
However, when such an identical potential pattern is completely conductive 
to the transparent electrodes, each transparent electrode on the large 
glass substrate cannot be electrically independent. Thus, before a cutting 
process, it is not possible to perform quality inspection to verify 
whether or not short-circuiting or disconnection occurs by bringing a 
pattern checker in contact with each transparent electrode. 
Accordingly, as shown in FIG. 3, there is a known conventional technique to 
provide minute gaps 3a of several microns for discharging static 
electricity at extensions from lead patterns 3 which are extended from a 
cell substrate-formed region S so as to be connected to an identical 
potential pattern 4 and are used as terminals leading from transparent 
electrodes 2 corresponding to each cell substrate. In other words, by 
providing the minute gaps 3a, which are also called "arresters", static 
electricity accumulated in the transparent electrodes 2 during the 
production process can be discharged through the minute gaps 3a. Thus, 
discharge between adjacent transparent electrodes 2 hardly occurs. In 
addition, each transparent electrode 2 is electrically, mutually 
independent by the provision of the minute gaps 3a. Therefore, convenience 
of quality inspection is improved because quality inspection with the 
pattern checker can be performed before the cutting process of the large 
glass substrate 1. 
As described above, in order to provide the minute gap 3a in the lead 
pattern 3, inevitably, the lead patterns 3 must be extended outward from 
each cell substrate-formed region so as to be connected to the identical 
potential pattern 4, and the minute gap 3a must be formed at the extended 
portions. Thus, as shown in FIG. 3, a predetermined space needs to be 
reserved between adjacent different cell substrate-formed regions S. 
Consequently, according to the related art, a high density layout in which 
a large number of cell substrate-formed regions S are formed is not 
realized. This reduces the number of cell substrates which are separately 
obtained from one large glass substrate 1, which hinders productivity 
improvement and cost reduction. 
SUMMARY OF THE INVENTION 
Accordingly, it is an object of the present invention to provide a liquid 
display device and a method for producing the same, in which minute gaps 
for discharging static electricity are formed at portions (outside an 
effective display region) of extension patterns leading from transparent 
electrodes separate from lead patterns, thereby, prevention of 
electrostatic destruction and quality inspection with a pattern checker 
can be performed without difficulty even if a high density layout of a 
plurality of cell substrate-formed regions arranged on a large glass 
substrate is used in a production phase, and a large number of cell 
substrates can be separately formed from one large glass substrate. 
To this end, according to an aspect of the present invention, the foregoing 
object has been achieved through the provision of a liquid crystal display 
device in which transparent electrodes mutually extending in parallel, and 
lead patterns used as terminals leading from ends of the transparent 
electrodes are formed on a cell substrate produced by separating a large 
glass substrate, wherein extension patterns leading from other ends of the 
transparent electrodes are formed on the cell substrate, and minute gaps 
for discharging static electricity accumulated in the transparent 
electrodes during a production process are formed at portions of the 
extension patterns outside an effective display region. 
Preferably, the minute gap is narrower than the gap between the adjacent 
transparent electrodes. 
The minute gaps may be overlaid with sealing agents. 
According to another aspect of the present invention, the foregoing object 
has been achieved through the provision of a method for producing a liquid 
crystal display device, comprising the steps of: providing on a large 
glass substrate capable of being separated to form a plurality of cell 
substrates, transparent electrodes mutually extending in parallel in each 
cell substrate-formed region, lead patterns used as terminals leading from 
ends of the transparent electrodes, extension patterns leading from other 
ends of the transparent electrodes, and an identical potential pattern 
outside the cell substrate-formed regions being conductive with the 
transparent electrodes via the lead patterns or the extension patterns, 
with the different cell substrate-formed regions being adjacently 
positioned; connecting the lead patterns in one cell substrate-formed 
region and the extension patterns in another cell substrate-formed region 
where the cell substrate-formed regions are adjacently positioned; 
providing minute gaps for discharging static electricity accumulated in 
the transparent electrodes during a production process at portions of the 
extension patterns within one cell substrate-formed region outside an 
effective display region; and cutting the large glass substrate into a 
plurality of separate cell substrates. 
According to the present invention, even if a liquid crystal display device 
employs a high density layout in which cell substrate-formed regions are 
formed on a large glass, prevention of electrostatic destruction and 
quality inspection with a pattern checker can be performed without 
difficulty because extension patterns in each cell substrate-formed region 
are provided with minute gaps. In addition, even when discharge of static 
electricity occurs in the minute gaps in a production process, display 
quality cannot be affected at all because the extension patterns outside 
an effective display region are damaged by arc heat. 
Moreover, by using a layout in which a plurality of cell substrate-formed 
regions are arranged at high density on the large glass substrate, a large 
number of cell substrates can be separately formed, which realizes both 
productivity improvement and cost reduction.

DESCRIPTION OF THE PREFERRED EMBODIMENT 
Referring to the attached drawings, FIG. 1 shows a plan view illustrating a 
layout (formed before a cutting process) of a cell substrate for a liquid 
crystal display device according to an embodiment of the present 
invention, and FIG. 2 shows a schematic sectional view illustrating a 
completed liquid crystal display device according to the present 
invention. Components corresponding to those shown in FIG. 3 illustrating 
the related art are denoted by identical reference numerals. 
A liquid crystal display device 5 shown in FIG. 2 is formed such that a 
cell substrate 7 including a transparent electrode (common electrode) 2 
and an orientation film 6, and a cell substrate 10 including transparent 
electrodes (segment electrodes) 8 and an orientation film 9 are stacked 
with a frame-shaped coat of sealing agent 11 provided therebetween so that 
their electrode-formed surfaces are opposed, and liquid crystal 12 is 
subsequently encapsulated in a space sealed by both cell substrates 7, 11 
and the sealing agent 11. 
As is generally known, both cell substrates 7 and 10 of the liquid crystal 
display device 5 are separately formed by cutting a large glass substrate 
with transparent electrodes and an orientation film formed thereon and an 
orientation process performed. In this embodiment, by using a layout for 
dense cell substrate-formed regions on the large glass substrate, a large 
number of cell substrates can separately be formed from one large glass 
substrate. 
For example, concerning one cell substrate 7, a large number of cell 
substrates are simultaneously, separately formed as follows: 
As shown in FIG. 1, transparent electrodes 2 extending mutually in parallel 
within each cell substrate-formed region S, lead patterns 3 used as 
terminals leading from ends of the transparent substrates 2, extension 
patterns 13 leading from other ends of the transparent substrates 2, and 
an identical potential pattern 4 positioned outside the cell 
substrate-formed region S which is conductive to the transparent 
electrodes 2 via the lead patterns 3 and the extension patterns 13, are 
initially formed on the large glass substrate 1 so that different cell 
substrate-formed regions S are adjacently positioned. At the same time, at 
portions where the cell substrate-formed regions S are adjacently 
positioned, the lead patterns 3 in one region S and extension patterns 13 
in another region S are connected. Subsequently, at portions of the 
respective extension patterns 13 which overlap with a region coated with 
the sealing agent 11 in proximity to the periphery of the region S within 
the cell substrate-formed region S, or definitely at portions positioned 
0.9 mm inside of the periphery of the region S, minute gaps 13a for 
discharging static electricity accumulated in the transparent substrate 2 
during a production process are formed. 
In addition, in order to arrange a plurality of cell substrate-formed 
regions S in the form of continuous columns, as shown in FIG. 1, it is 
preferable to use a layout in which the lead patterns 3 extend from the 
cell substrate-formed region S positioned at one end of a column to 
connect to the identical potential pattern 4. Thus, at extensions of the 
lead patterns 3 which are connected to the identical potential pattern 4, 
the minute gaps 3a are formed similar to the related art. 
FIG. 1 shows a condition obtained after forming the minute gaps 13a and the 
minute gaps 3a. Accordingly, each transparent electrode 2 is electrically, 
mutually independent, and is free from conduction to the identical 
potential pattern 4. Each of the minute gaps 13a and the minute gaps 3a is 
set to 6 microns, which is narrower than the gap between adjacent 
transparent electrodes 2. 
By providing a minute gap 13a at the predetermined portion of each lead 
pattern 13, even if a liquid crystal display device employs an 
area-efficient layout in which a plurality of cell substrate-formed 
regions S are continuously formed on one large glass substrate 1, or a 
high density layout in which different cell substrate-formed regions S are 
adjacently positioned, electrostatic destruction of transparent electrode 
2 can be prevented because static electricity accumulated in the 
transparent electrode 2 can be discharged through the minute gap 13a 
during a rubbing orientation process or the like. In addition, by 
providing minute gaps 13a, each transparent electrode 2 on the large glass 
substrate 2 can be electrically independent. Thus, before a cutting 
process, it is possible to perform quality inspection by bringing a 
pattern checker in contact with the liquid crystal display device in order 
to verify whether or not short-circuiting or disconnection occurs. 
After quality inspection of each transparent electrode 2 has been finished, 
the large glass substrate 1 is cut along predetermined lines to form 
separate cell substrates 7. As described above, a plurality of cell 
substrate-formed regions S are arranged at high density on the large glass 
substrate 1. Thus, according to this embodiment, a large number of cell 
substrates 7 can be simultaneously, separately formed from one large glass 
substrate 1. As a result, productivity of liquid crystal display devices 5 
increases to reduce a production cost. 
If electrostatic discharging occurs at the minute gap 13a in the production 
process, the extension pattern 13 is damaged by arc heat. But, a portion 
where such damage supposedly occurs is in the vicinity of the minute gap 
13a, on which the sealing agent is stacked, or is outside the effective 
display region of the cell substrate 7, which thus does not deteriorate 
display quality even if static electricity is discharged. 
In the foregoing embodiment, only a method for producing one cell substrate 
7 for the liquid crystal display device 5 has been described, but it need 
hardly be said that also another cell substrate 10 can be efficiently 
produced at a low cost in the same manner.