Electricity: measuring and testing – Fault detecting in electric circuits and of electric components
Reexamination Certificate
2000-01-20
2002-04-09
Metjahic, Safet (Department: 2858)
Electricity: measuring and testing
Fault detecting in electric circuits and of electric components
C324S537000, C324S538000, C324S539000, C324S1540PB
Reexamination Certificate
active
06369580
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to a device and method for inspecting stripe electrode patterns formed on a substrate, so as to detect defects in the patterns.
BACKGROUND OF THE INVENTION
Conventionally, in a large-scale liquid crystal display element capable of displaying high-definition characters and images, a plurality of transparent electrodes are formed in a stripe form so that fine-pitched electrode patterns are provided on one of two transparent substrates in pair composing the liquid crystal display element.
In a process of fabrication of the transparent substrate with such transparent electrodes, used as a common technique to detect defects in the electrode patterns are {circumflex over (1)} a method disclosed in the Japanese Publication for Laid-Open Patent Application No. 333357/1993 (Tokukaihei 5-333357 [Issue Date: Dec. 17, 1993]), and {circumflex over (2)} a method disclosed in the Japanese Publication for Laid-Open Patent Application No. 230188/1990 (Tokukaihei 2-230188 [Issue Date: Sep.
12
,
1990
]).
In the case where the method {circumflex over (1)} is adopted, used is an inspection device
101
provided with, as shown in
FIG. 6
, a first voltage inspection terminal
102
, a voltage application terminal
103
, a second voltage inspection terminal
104
, an inspecting voltage application circuit
105
, a defect detection circuit
106
, and a short-circuiting/wire breakage memory circuit
107
. The voltage application terminal
103
is connected with the inspection voltage application circuit
105
, while the first and second voltage inspection terminals
102
and
104
are connected with the defect detection circuit
106
. The defect detection circuit
106
is connected with the short-circuiting/wire breakage memory circuit
107
, and is also earthed.
The plurality of transparent electrodes (electrode patterns)
121
in a stripe form are formed on the transparent substrate
120
as described above, and the voltage application terminal
103
is in contact with an end of one transparent electrode
121
a thereamong, while the first voltage inspection terminal
102
is in contact with the other end of the transparent electrode
121
a.
Likewise, the second voltage inspection terminal
104
is in contact with an end of a transparent electrode
121
b
adjacent to the transparent electrode
121
a,
the end being on the first voltage inspection terminal
102
side. If the defect detection circuit
106
detects no conduction between the voltage application terminal
103
and the first voltage inspection terminal
102
upon application of a voltage by the inspection voltage application circuit
105
, it follows that the transparent electrode
121
a
is broken. If the defect detection circuit
106
detects conduction between the voltage application terminal
103
and the second voltage inspection terminal
104
, it follows that the transparent electrodes
121
a
and
121
b
are short-circuited. The foregoing defect information thus detected is outputted to and stored in the short-circuiting/wire breakage memory circuit
107
.
By driving the three terminals, that is, the voltage application terminal
103
and the first and second voltage inspection terminals
102
and
104
, in a direction crossing the transparent electrodes
121
in a stripe form so as to scan the transparent electrodes
121
, all the transparent electrodes
121
on the transparent substrate
120
are subjected to inspection on presence/absence of wire breakage and short-circuiting.
On the other hand, in the case where the method {circumflex over (2)} is adopted, used is a transparent substrate
122
, as shown in
FIG. 7
, having a common electrode
124
formed at a peripheral part thereof outside to transparent electrodes (electrode patterns)
123
arranged in a stripe form and connected with every other transparent electrode
123
. More specifically, the transparent substrate
122
used when the method {circumflex over (2)} is applied is designed so that thereon alternately arranged are transparent electrodes
123
a
connected with the common electrode
124
and transparent electrodes
123
b
not connected therewith. Further, as shown in
FIG. 7
, an inspection device
110
used in this method is designed in the same manner as the inspection device
101
used in application of the method {circumflex over (1)} except that not two voltage detection terminals, but a single voltage inspection terminal
108
is used alone.
The foregoing voltage application terminal
103
is brought into contact with the common electrode
124
, while the voltage inspection terminal
108
is brought into contact with an end of one transparent electrode
123
and makes the contact scan in a direction crossing the transparent electrodes
123
. In the case of one transparent electrode
123
a
not connected with the common electrode
124
, without short-circuiting, a voltage is not detected from the voltage inspection terminal
108
by the defect detection circuit
106
, whereas with short-circuiting, a voltage is detected. Conversely, in the case of one transparent electrode
123
b
connected with the common electrode
124
, without wire breakage, a voltage is detected from the voltage inspection terminal
108
by the defect detection circuit
106
, whereas with wire breakage, voltage is not detected.
Therefore, without any irregularity such as wire breakage or short-circuiting in the transparent electrodes
123
, some transparent electrodes
123
at which a voltage is detected (voltage-detected transparent electrodes
123
) and some transparent electrodes
123
at which a voltage is not detected (voltage-non-detected transparent electrodes
123
) appear alternately (voltage is detected from the transparent electrodes
123
b
connected with the common electrode
124
while voltage is not detected from the transparent electrodes
123
b
not connected with the common electrode
124
). With wire breakage or short-circuiting, however, voltage-detected transparent electrodes
123
or voltage-non-detected transparent electrodes
123
appear successively.
Therefore, such successive appearance of voltage-detected transparent electrodes
123
or voltage-non-detected transparent electrodes
123
is detected by the defect detection circuit
106
as a defect of wire breakage or short-circuiting, and it is, as defect information, outputted to and stored in the short-circuiting/wire breakage memory circuit
107
.
The foregoing conventional methods have the following problems, however.
First of all, the transparent electrodes
121
subjected to an inspection by the method {circumflex over (1)} have to be in a complete stripe form. The reason is as follows: since the voltage application terminal
103
and the first and second voltage inspection terminal
102
and
104
are in point contact with ends of the transparent electrodes
121
, if the pitch of ends of the transparent electrodes
121
varies somewhere, an adequate electric circuit is not provided, thereby making inspection impossible.
Further, the method {circumflex over (1)} requires high precision in positioning of the terminals and the plurality of transparent electrodes
121
disposed on the transparent substrate
120
. In other words, unless the parallelized state of the terminals is set accurately and precisely, the terminals and the transparent electrodes
121
do not form an adequate electric circuit. Likewise, unless the transparent electrodes
121
are disposed at precise and accurate positions on the transparent substrate
120
, the parallel state of the terminals has to be set for each inspected transparent substrate
120
independently. To realize such high precision in positioning, a system for high-precision positioning system is needed, thereby bringing about an increase in costs.
Furthermore, the method {circumflex over (1)} is incapable of inspection of electrode patterns designed so that an end of every transparent electrode
121
is connected with the above-described electrode
124
. In other words, according to the metho
Kageyama Tetsuya
Takashima Naoki
Conlin David G.
Edwards & Angell LLP
Hamdan Wasseem H.
Jensen Steven M.
Metjahic Safet
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