KR101543020B1 - Method of testing for connection condition between display panel and pcb and liquid crystal display device using the same - Google Patents

Abstract

The present invention relates to a liquid crystal display, and more particularly, to a liquid crystal display having a first test point electrically connected to a first pad and a third test point electrically connected to a second pad, And a connecting board connected to the liquid crystal panel and having a second test point electrically connected to the third pad and a fourth test point electrically connected to the fourth pad.

FOG, liquid crystal panel, connection board, test, resistance

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to a liquid crystal display (LCD)

The present invention relates to a method of testing a connection state between a liquid crystal panel and a connection substrate, and a liquid crystal display using the same.

Recently, as the information society has advanced rapidly, there has been a need for a flat panel display having excellent characteristics such as thinning, light weight, and low power consumption. Among these, a liquid crystal display device , Color display, image quality, and the like.

In general, in a liquid crystal display device, two substrates on which electrodes are formed are arranged so that the surfaces on which the two electrodes are formed face each other, a liquid crystal material is injected between the two substrates, and then an electric field And moving the liquid crystal molecules, thereby expressing the image by the transmittance of light depending on the liquid crystal molecules.

Such a liquid crystal display device includes a liquid crystal panel in which liquid crystal is injected between two substrates, a backlight unit disposed under the liquid crystal panel and used as a light source, and a driving unit for driving the liquid crystal panel, which is located outside the liquid crystal panel.

A chip on glass (COG) mounting method in which a driver circuit of a liquid crystal display device is directly bonded to a liquid crystal panel in accordance with the tendency of the liquid crystal display device to be made lighter, thinner, and lower in cost and a flexible printed circuit board A film on glass (FOG) mounting method is adopted.

The COG and FOG mounting methods use an anisotropic conductive film to electrically and mechanically connect the driving circuit or the flexible printed circuit board to the liquid crystal panel.

The present invention provides a liquid crystal display device capable of testing a connection state between a liquid crystal panel and a connection substrate.

A liquid crystal display according to an embodiment of the present invention includes a liquid crystal panel having a first test point electrically connected to a first pad and a third test point electrically connected to a second pad; And a connecting board connected to the liquid crystal panel and having a second test point electrically connected to the third pad and a fourth test point electrically connected to the fourth pad.

A method of testing a connection state of a liquid crystal panel and a connection board according to an exemplary embodiment of the present invention includes a first test point electrically connected to a first pad and a liquid crystal panel including a third test point electrically connected to a second pad, Connecting a second test point electrically connected to the third pad and a connection substrate formed with a fourth test point electrically connected to the fourth pad; And testing the connection state of the display panel and the connection board.

According to the present invention, it is possible to test the connection state between the liquid crystal panel and the connection substrate by measuring the resistance value by adding test points to the liquid crystal panel and the connection substrate, respectively.

It is possible to perform full inspection by using the above test method and also to automate FOG bonding inspection.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

1 is a front view showing a liquid crystal display device according to an embodiment of the present invention.

Referring to FIG. 1, a liquid crystal display includes a liquid crystal panel 10, a panel driver 20, and a connection board 30.

The liquid crystal panel 10 displays an image by adjusting the intensity of the passing light in units of pixels. The liquid crystal panel 10 includes a color filter substrate and a thin film transistor substrate bonded together with a liquid crystal therebetween. The liquid crystal panel 10 includes a plurality of liquid crystal cells arranged at the intersections of the data lines and the gate lines in a matrix form.

A thin film transistor (TFT) formed in each of the liquid crystal cells charges an image signal supplied from a data line in response to a scan signal supplied from a gate line to the liquid crystal cell. The liquid crystal cell drives the liquid crystal having dielectric anisotropy according to the charged image signal to adjust the light transmittance.

On the liquid crystal panel 10 according to the present invention, test points 41 and 43 for testing the connection state with the connection substrate 30 are formed.

The panel driving unit 20 is mounted on the thin film transistor substrate of the liquid crystal panel 10 by a COG (Chip On Glass) method to drive the liquid crystal panel 10.

The connection substrate 30 is connected to the thin film transistor substrate. The connection substrate 30 is bonded to the thin film transistor substrate and electrically connected thereto. The connection board 30 is a flexible printed circuit board (FPCB).

The connection substrate 30 is connected to the liquid crystal panel 10 by an anisotropic conductive film (ACF, not shown).

FIG. 2A is a front view showing a part of a liquid crystal panel 10 according to an embodiment of the present invention, and FIG. 2B is a front view showing a part of a connection board 30 according to an embodiment of the present invention.

The liquid crystal panel 10 includes a plurality of connection pads 50, a first pad 51, a second pad 52, a first test point 41 and a third test point 43.

The connection pads 50 are connected to the connection pads 60 of the connection board 30 and receive data for displaying driving signals and images from the system.

The first pad 51 and the second pad 52 are disposed outside the connection pads 50. That is, the connection pads 50 are arranged side by side, and the first pad 51 and the second pad 52 are disposed at the outermost side.

Specifically, the first pad 51 is disposed on the left outside of the liquid crystal panel 10, and the second pad 52 is disposed on the right outside of the liquid crystal panel 10.

The first pad 51 and the second pad 52 are connected to the third pad 61 and the fourth pad 62 of the connection board 30 in a corresponding manner.

That is, the first pad 51 and the second pad 52 are disposed at the leftmost and rightmost outermost sides, respectively, and the third pad 61 and the fourth pad 62 are also disposed at the outermost left and right do.

An anisotropic conductive film layer (not shown) is interposed between the connection substrate 30 and the liquid crystal panel 10. That is, an anisotropic conductive tape may be disposed between the connection substrate 30 and the liquid crystal panel 10, and pressure may be applied to the connection substrate 30 and the liquid crystal panel 10.

At this time, relatively stronger pressure is applied to the regions corresponding to the third pad 61 and the fourth pad 62 and the first pad 51 and the second pad 52. In addition, stronger pressure is applied to the regions corresponding to the connection pads 50 of the liquid crystal panel 10 and the connection pads 60 of the connection substrate 30. [

Accordingly, the conductive particles included in the region between the connection pads 50 of the liquid crystal panel 10 and the connection pads 60 of the connection substrate 30 are in contact with each other and are electrically connected.

That is, conductive regions are formed between the connection pads 50 of the liquid crystal panel 10 and the connection pads 60 of the connection substrate 30. [

The connection pads 50 of the liquid crystal panel 10 and the connection pads 60 of the connection substrate 30 are connected to each other via the connection pads 50 of the liquid crystal panel 10, The electrical characteristics between the connection pads 60 of the liquid crystal display device 30 affect the performance of the liquid crystal display device.

Particularly, the short circuit between the first pad 51 and the second pad 52, the third pad 61 and the fourth pad 62, and the magnitude of the connection resistance should be tested.

The connection between the connection pads 50 of the liquid crystal panel 10 and the connection pads 60 of the connection substrate 30 is determined by the connection between the first pad 51 and the second pad 52, (61) and the fourth pad (62).

The first test points 41 on the left side of the liquid crystal panel 10 are electrically connected to each other through the first pad 51 and the connection line 45. [ The third test points 43 on the right side of the liquid crystal panel 10 are electrically connected to each other through the second pad 52 and the other connection line 46.

The second test points 42 on the left side of the connecting board 30 are electrically connected to each other through the third pad 61 and the connecting line 47. The fourth test point 44 on the right side of the connection board 30 is electrically connected to the fourth pad 62 via the connection line 48.

3 is a view illustrating a state of testing connection between a liquid crystal panel and a connection substrate according to an embodiment of the present invention.

As described above, the first test point 41 and the third test point 43 present on the liquid crystal panel 10 and the second test point 42 and the fourth test The connection state is tested for each of the points 44 using a resistance value measuring device. In this case, the connection resistance values at both ends are tested, and if the reference resistance value is exceeded, the connection state can be classified as being poor.

That is, the above-mentioned test points 41, 42, 43, and 44 have a predetermined area and are formed by being exposed to the outside, and a probe of a tester or a measuring instrument is contacted.

By using this test method, it is possible to further quantify the existing visual inspection and sampling inspection, and it is also possible to perform full inspection. In addition, a resistance value measuring device may be separately provided to realize the inspection automation.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is to be understood that the invention is not limited to the disclosed exemplary embodiments, but, on the contrary, It will be understood by those skilled in the art that various changes and modifications may be made by those skilled in the art without departing from the spirit and scope of the present invention.

1 is a front view showing a liquid crystal display device according to an embodiment of the present invention.

2A is a front view showing a part of a liquid crystal panel according to an embodiment of the present invention.

2B is a front view showing a part of a connection board according to an embodiment of the present invention.

3 is a view illustrating a state of testing connection between a liquid crystal panel and a connection substrate according to an embodiment of the present invention.

Claims (7)

A plurality of first connection pads, a first pad arranged side by side on one side of the plurality of first connection pads, a second pad side by side on the other side of the plurality of first connection pads, And a third test point electrically connected to the second pad; And A third pad connected to the liquid crystal panel and having a plurality of second connection pads, a third pad arranged in parallel with one side of the plurality of second connection pads, a fourth pad arranged in parallel with the other side of the plurality of second connection pads, A second test point electrically connected to the third pad, and a fourth test point electrically connected to the fourth pad are formed. The method according to claim 1, Wherein the first pad and the second pad are formed at positions corresponding to the third pad and the fourth pad, respectively. 3. The method of claim 2, And an anisotropic conductive film layer interposed between the liquid crystal panel and the connection substrate, wherein the first and second pads are electrically connected to the third and fourth pads by the anisotropic conductive film layer. The method of claim 3, Wherein the first pad overlaps with and is in surface contact with the third pad, and the second pad overlaps with the fourth pad to face each other. A plurality of first connection pads, a first pad arranged side by side on one side of the plurality of first connection pads, a second pad side by side on the other side of the plurality of first connection pads, A plurality of second connection pads on the liquid crystal panel having a first test point electrically connected to the first pad and a third test point electrically connected to the second pad, a third pad arranged on one side of the plurality of second connection pads, A fourth pad disposed in parallel with the other of the plurality of second connection pads, a second test point electrically connected to the third pad, and a connection substrate formed with a fourth test point electrically connected to the fourth pad, ; And And testing the connection state of the liquid crystal panel and the connection substrate. The method according to claim 5, wherein the step of testing the connection state of the liquid crystal panel and the connection substrate comprises: Measuring a resistance between the first test point and the second test point to determine that the connection state is poor when the reference value is exceeded; and testing the connection state of the connection panel. The method according to claim 5, wherein the step of testing the connection state of the liquid crystal panel and the connection substrate comprises: Measuring a resistance between the third test point and the fourth test point, and determining that the connection state is poor when the reference value is exceeded.

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