Electricity: measuring and testing – Impedance – admittance or other quantities representative of... – Lumped type parameters
Reexamination Certificate
1999-06-09
2001-06-12
Metjahic, Safet (Department: 2858)
Electricity: measuring and testing
Impedance, admittance or other quantities representative of...
Lumped type parameters
C324S678000, C250S205000, C250S225000, C073S603000
Reexamination Certificate
active
06246253
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a system for testing liquid crystal and end seal of liquid crystal display cell, and more particularly to a system for testing distributing state of the liquid crystal being injected through a liquid crystal injecting hole and for testing coating state of end seal used for sealing the injecting hole after the liquid crystal is injected.
2. Description of the Related Art
The liquid crystal cell is generally fabricated according to the following steps of; coating a polymeric organic alignment layer between electrodes, i.e. transparent conductors being attached to respectively opposed surfaces of upper and lower glass substrates and rubbing the alignment layer; printing a thermosetting sealing material that a spacer is mixed therein, on the lower glass substrate so as to maintain a selected distance (7~10 &mgr;m) between the upper and lower glass substrates; attaching the upper glass substrate and the lower glass substrate; and curing the resultant.
There are various techniques for injecting the liquid crystal into the liquid crystal cell, such as those methods of employing yarn made of fiber material, boating and dipping.
According to the method employing yarn, sufficient amount of liquid crystal is absorbed by the yarn made of fiber materials and the yarn is inserted into a boat through a slot provided in the boat. The boat is located adjacent to a liquid crystal injecting hole formed in a liquid crystal cell. And then, the liquid crystal is injected into inner space of the liquid crystal cell according to a vacuum pressure which is preexisted in a liquid crystal injecting chamber and an absorptivity due to the capillary phenomenon.
On the other hand, according to the boating method, the liquid crystal is directly poured into the liquid crystal injecting hole without employing any yarn. According to the dipping method, the liquid crystal is injected by dipping the liquid crystal injecting hole into a tray which is filled with liquid crystal in full.
Accordingly, there are formed two liquid crystal injecting holes at a side of the liquid crystal cell. The liquid crystal is injected through the respective liquid crystal injecting holes, and then the liquid crystal injecting holes are sealed with end seal to prevent from leaking the liquid crystal. Herein, the end seal is generally coated at an outer surface of the liquid crystal injecting hole at a thick of 0.1~0.8 mm.
After the liquid crystal injecting hole is sealed with the end seal, uniformity of liquid crystal distribution in the liquid crystal cell is investigated. The reason for investigating the uniformity is because there may be occurred malfunctions when the liquid crystal is not injected uniformly into some portions of the liquid crystal cell. Further, the thickness of end seal must be limited and be uniformed in the range as mentioned above. Only by doing so, leaking of liquid crystal is prevented, and therefore the sealing condition can be investigated.
Conventionally, there are provided an equipment for testing the liquid crystal distribution and another equipment for testing end seal condition, and especially the sealing condition is investigated about the whole liquid crystal cells by means of a microscope.
However, those equipments whose testable range of cell size is limited within 12.1″ will be useless since currently the size of liquid crystal cell becomes larger.
Furthermore, since those equipments are separately installed, they require two investigators, which is regarded to as wasting of manpower and there may be occurred scraps in the liquid crystal cells while transferring the liquid crystal cells from one equipment to another equipment.
Since the sealing condition is investigated about the whole liquid crystal cells by means of a microscope, the investigator has eyestrain that results in inaccuracy of the test.
SUMMARY OF THE INVENTION
Accordingly, the present invention is provided to solve foregoing problems of conventional testing systems and more specifically the present invention provides a system for testing liquid crystal and end seal of liquid crystal display cell so that various size of cells are all testable by the system.
It is another object of the present invention that one investigator can conduct two tests by accomplishing the respective tests for liquid crystal and for end seal within one system. Additionally, the scrap in the liquid crystal cells during the cell transfer is prevented by transferring them with a robot which is precisely controlled.
It is further object of the present invention to prevent the investigator's eyestrain and to improve accuracy of the test by providing an extended screen when the sealing condition is tested by the investigator.
So as to accomplish foregoing objects, a testing system according to the present invention is constituted as follows.
A test unit for distribution of liquid crystal being injected into liquid crystal cells is disposed at one side of a unit that a cassette enclosing liquid crystal cells is loaded therein. A test unit for end seal being used for sealing a liquid crystal injecting hole is disposed at one side of the liquid crystal distribution testing unit in an orthogonal position thereto. The liquid crystal cells being decided as good, repair, reject according to test results of the respective units, are selectively unloaded to three unloading units. The unloading units are disposed in parallel with the test unit for liquid crystal by a selected distance and disposed in the orthogonal position with respect to the test unit for end seal. Between the respective testing units and the unloading units, a robot unit holding a liquid crystal cell and transferring it to the respective units one by one is disposed.
The test unit for liquid crystal includes a main frame provided with a means for aligning the liquid crystal cells. Lamps are installed on a bottom of the main frame. The light of the lamps are emitted toward lower portions of the liquid crystal cells which are aligned by the aligning means. A lower polarizing plate is positioned rotatively between the lamps and the liquid crystal cells. An upper polarizing plate is disposed at upper portions of the liquid crystal cells. A projecting mirror for projecting the distribution of the liquid crystal is disposed obliquely on the upper polarizing plate. The investigator decides the distribution condition of the liquid crystal cells with the projecting mirror.
The aligning means includes a first rack and a second rack which are positioned up and down in parallel. Midway portions of the racks are engaged with a pinion and both ends of the racks are connected to a first slider and a second slider. Especially, one end of the first rack is fixed on the first slider and the other end of the first rack is inserted movably in the second slider. On the other hand, one end of the second rack toward the same direction with the end of first rack is inserted movably in the first slider, and the other is fixed on the second slider. Accordingly, if one rack is moved in the left or right, i.e. in a horizontal way, the other rack is moved opposite to the moving direction according to the engagement operation through the pinion. A third rack and a fourth rack are positioned up and down onto the first and second sliders and they are also engaged with a pinion. Four putting arms are installed at both ends of the third and fourth racks. Corners of the liquid crystal cell are laid on the four putting arms. The connecting mechanism between the putting arms and both ends of the third and fourth racks is similar to those between the first and second racks, and the first and second sliders. A sensor for sensing the liquid crystal cell is installed at one among the four putting arms so that the robot unit is controlled in accordance with the sensing means.
A sensor bracket is installed at a slider positioned at an entrance to which the robot unit enters. A light emitting sensor and a light receiving sensor are attached to t
Jeong Suk Jin
Kang Eung Cheol
Yoon Chan Joon
Hamdan Wasseem H.
Hyundai Electronics Industries Co,. Ltd.
Ladas & Parry
Metjahic Safet
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