Data processing: measuring – calibrating – or testing – Measurement system in a specific environment – Mechanical measurement system
Reexamination Certificate
2000-11-13
2003-03-04
Barlow, John (Department: 2863)
Data processing: measuring, calibrating, or testing
Measurement system in a specific environment
Mechanical measurement system
C702S081000, C702S084000, C324S701000, C438S030000
Reexamination Certificate
active
06529837
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to a liquid crystal display, and more particularly to an apparatus and method for inspecting a cell defect of a liquid crystal display device that is adaptive for shortening an inspection time and improving a working efficiency in a inspection work of a bad pixel as well as improving a yield in a repairing work.
2. Description of the Related Art
Generally, a liquid crystal display (LCD) is completed by carrying out various processes such as a process of fabricating the upper plate and the lower plate of a panel accompanying a formation process of a liquid crystal cell, a formation and rubbing process of an alignment film for aligning the liquid crystal, a process of bonding the upper plate to the lower plate, and a process of injecting and sealing the liquid crystal between the bonded upper plate and lower plate. The process of fabricating the lower plate includes a formation step of a thin film transistor (TFT) part and a formation step of other electrode part according to a work of coating an electrode material, a semiconductor layer and an insulating film on a substrate and etching the same. When the liquid crystal injection and sealing process has performed and then a polarizer is attached to both surfaces of the upper and lower plates to complete a liquid crystal display panel, a final inspection work is made.
In the final inspection process, test patterns are expressed on a screen of the completed liquid crystal display panel to probe the presence or absence of a bad pixel. If a bad pixel is found, a repairing work for the bad pixel is performed. The badness of the LCD panel includes point defects such as a poor color of each pixel cell, a bright point (i.e., always turned-on cell) and a dark point (i.e., always turned-off cell), etc. and line defects caused by a short between the adjacent data lines. Such badness is clearly come out to a worker's eye when the test patterns are expressed on the completed LCD panel. Then, the worker grasps a position of a bad pixel to perform a repairing work for the bad pixel position later.
FIG. 1
is a block diagram showing a configuration of a conventional cell badness inspecting apparatus for a liquid crystal display device. Referring to
FIG. 1
, the conventional inspecting apparatus includes an auto probe
20
for loading a LCD panel to be inspected and then inspecting the same, a pattern generator
22
for applying a test pattern signal to the LCD panel loaded on the auto probe
20
, a manual operation box
24
for acquiring a co-ordinate value of a position at which a bad pixel is found in the inspecting process, and a laser repair device
26
for repairing the bad pixel of the LCD panel using a laser beam. The auto probe
20
includes a loader
28
for carrying a LCD panel to be inspected from the exterior thereof into the interior thereof, an unloader
30
for carrying an inspection-completed LCD from the auto probe
20
into the exterior thereof, an inspector for making an inspecting work for the loaded LCD panel, and a robot transporter
34
for carrying the LCD panel put on the loader
28
into the inspector
32
or carrying the LCD panel positioned at the inspector
32
into the unloader
30
after completion of the inspection. The pattern generator
22
is interfaced with the inspector
32
of the auto probe
20
to apply a test pattern signal to the inspector
32
. Also, the pattern generator
22
is interfaced with the manual operation box
24
by means of a RS-232 port and the like to control an application of the test pattern signal by means of an operation button of the manual operation box
24
. The manual operation box
24
is provided with a cursor operation button, thereby allowing a worker to control a position of the cursor appearing on the screen of the LCD panel upon inspection in the up, down, left and right direction.
Hereinafter, a process of inspecting and repairing pixel badness in a LCD panel using the conventional inspecting apparatus configured as mentioned above will be described. First, a LCD panel to be inspected at the loader
28
of the auto probe
20
is carried from the exterior into the interior of the auto probe
20
. The LCD panel carried into the loader
28
is sent to the inspector by means of the robot transporter
34
. When the LCD panel is safely loaded on the inspector
32
of the auto probe
20
, the pattern generator
22
generates a test pattern signal in response to a control signal applied from the manual operation box
24
to apply the test pattern signal to the inspector
32
of the auto probe
20
. Then, a test pattern is expressed on a screen of the LCD panel loaded on the inspector
32
of the auto probe
20
. Thus, a worker observes this screen to inspect whether or not a bad pixel exists. At this time, a worker's eye senses pixel badness such as a poor color, a bright point, a dark point and a line defect, etc. At the same time, a cursor moved by an operation button of the manual operation box
24
is emerged on the screen of the LCD panel, and X-Y co-ordinates are displayed at the edge portion of the screen. The worker grasps a position of the bad pixel and then operates the cursor operation button of the manual operation box
24
to move a position of the cursor into the position of the bad pixel. The X-Y co-ordinate values of the bad pixel are displayed at the edge portion of the screen when the cursor has been moved to the bad pixel position. Then, the worker writes the co-ordinate values of the bad pixel displayed on the screen onto a work paper. Such a process is repeated until co-ordinate values of all the bad pixels have been known. After the co-ordinate values of all the pad pixels were known, the LCD panel loaded on the inspector
32
is transported into the unloader
30
by means of the robot transporter
34
and then is sent from the unloader
30
into the exterior of the auto probe
20
. Subsequently, a LCD panel being subject to the next inspection is carried to the loader
28
of the auto probe
20
. A LCD panel in which bad pixels are found in the inspecting process is sent to the laser-repairing device
26
to perform a repairing work for the bad pixels. At this time, a worker sees the work paper on which the co-ordinate values of the bad pixels found in the inspecting process has been written to perform a repairing work. In the laser repairing device
26
, a transporting robot moves a laser beam generator into co-ordinates of the bad pixel written on the work paper to emit a laser beam to the corresponding bad pixel, thereby performing a repairing work of the liquid crystal cell. A general liquid crystal repairing method takes advantage of shorting TFT's of the liquid crystal cell by a laser beam to make a bright point of the corresponding cell or of opening the electrodes to make a dark point of the corresponding cell.
However, since the conventional LCD panel inspecting process must put the cursor operation button of the manual operation box
24
in every thing to move a position of the cursor into a position of the bad pixel so as to acquire co-ordinate values of the bad pixel as mentioned above, it has a problem in that a work time is lengthened and a work efficiency is deteriorated. Because the cursor operation button included in the existent manual operation box
24
makes a position control of the cursor in the up, down, left and right direction, a lot of button operation frequencies are required for moving the cursor into a position of the bad pixel and a work time is lengthened, to thereby deteriorate a work efficiency. Furthermore, the conventional inspecting process has a problem in that, since co-ordinate values of a bad pixel acquired in the above manner are written on a work paper in every thing by a worker to allow the worker to perform a repair work seeing the co-ordinate value data written on the work paper later rather than being automatically transmitted to the laser repairing device
26
, a work efficiency is not only deteriorated, but also a yie
Barlow John
LG. Philips LCD Co. Ltd.
McKenna Long & Aldridge LLP
Vo Hien
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