KR100806910B1 - liquid crystal device and method for measuring bonding state in manufacturing the liquid crystal device - Google Patents

Abstract

The present invention relates to a liquid crystal display and a method for measuring bonding state in the manufacture thereof.

In the present invention, a plurality of pixels having switching elements connected to the gate line and the data line are formed in an area defined by the intersection of the gate line and the data line, respectively, and a plurality of pads for signal transmission to one side of each gate line and the data line. In the liquid crystal display device comprising a substrate including a pad portion connected to the gate driver for supplying a gate driving signal to the gate line and a data driver for supplying an image data signal to the data line to bond the pad portion in the The method comprising: positioning a conductive material including conductive particles in the pad part; Bonding each signal terminal of the gate driver and the data driver to correspond to each pad of the pad part; Selecting a terminal to which the same signal is input from among the signal terminals of the gate driver and the data driver; Measuring contact resistances between the terminals of each of the selected driving units and pads of the pad unit bonded corresponding to the terminals; And determining whether bonding between the driving unit and the pad unit is normally performed based on the measured contact resistance.

According to the present invention, when bonding is performed for signal connection at the time of manufacturing a liquid crystal display, it is easy to measure whether bonding is normally performed.

LCD, bonding, contact resistance, monitoring window, pad

Description

Liquid crystal display and method for measuring bonding state in manufacturing thereof

1 is a diagram schematically illustrating a structure of a liquid crystal display according to an exemplary embodiment of the present invention.

FIG. 2 is a view schematically illustrating a structure of a pad portion on a substrate for bonding with a driving portion in a liquid crystal display according to an exemplary embodiment of the present invention.

3 is a structural diagram for measuring a bonding state in the manufacture of a liquid crystal display according to a first embodiment of the present invention.

4 is a structural diagram of a pad unit for measuring a bonding state in manufacturing a liquid crystal display according to a second exemplary embodiment of the present invention.

The present invention relates to a liquid crystal display device, and more particularly, to a method for measuring a chip bonding state in a liquid crystal display device.

The liquid crystal display is one of the most widely used flat panel display devices. The liquid crystal layer between the two substrates and the two substrates on which the plurality of electrodes for generating the electric field are formed and attached to the outer surface of each substrate polarizes light. It consists of two polarizing plates, and is a display device for controlling the amount of light transmitted by rearranging the liquid crystal molecules of the liquid crystal layer by applying a voltage to the electrode. A thin film transistor is formed on one substrate of the liquid crystal display, which serves to switch the voltage applied to the electrode.

In the center portion of the substrate where the thin film transistor is formed, a display area where a screen is displayed is located. In the display area, a plurality of signal lines, that is, a plurality of gate lines and data lines, are formed in the row and column directions, respectively. The pixel electrode is formed in the pixel region defined by the intersection of the gate line and the data line, and the thin film transistor controls the data signal transmitted through the data line according to the gate signal transmitted through the gate line, and sends it out to the pixel electrode.

Outside the display area, a plurality of gate pads and data pads are respectively connected to the gate line and the data line, and the pads are directly connected to an external driving integrated circuit to receive gate and data signals from the outside and receive the gate line and data. Deliver on the line.

A gate printed circuit board and a data printed circuit board are attached to the thin film transistor substrate through a thermocompression bonding process using an anisotropic conducting film (ACF). Between the thin film transistor substrate and the printed circuit board for data, it is connected to a data signal transmission film (FPC) equipped with a data driving integrated circuit that converts an electrical signal into a data signal and outputs it to a data pad and a data line. It is. In addition, a film for gate signal transmission is mounted between the thin film transistor substrate and the gate printed circuit board, in which a gate driving integrated circuit is mounted, which converts an electrical signal into a gate signal and outputs the result to a gate pad and a gate line.

In the structure in which the data driver integrated circuit and the gate driver integrated circuit are connected to the thin film transistor substrate and the printed circuit board through the transfer film, an anisotropic conductive film is placed on the pad formed on the thin film transistor substrate (or the printed circuit board), After placing the pad of the wiring formed in the film for transmission so as to correspond to the pad of the board | substrate on the anisotropic conductive foil, bonding is performed using ACF. As a result, the conductive particles (hereinafter referred to as "conductive balls") contained in the anisotropic conductive film are broken, and conduction is generated between the pad on the substrate and the transfer film so that a signal can be transmitted.

However, in this bonding process, the conductive balls do not break evenly. If the conductive ball is not broken in the form for normal signal transmission during the compression between the pad of the transfer film and the pad on the substrate, distortion occurs during signal transmission.

In the related art, a separate measuring instrument or a method of visually confirming a pressure state using a pressurized paper was used to monitor the breaking form of the conductive ball. However, the cost of using a separate device is increased, or a problem such as delay in the manufacturing process due to the addition of a separate process for monitoring the state of the conductive ball using a pressurized paper.

On the other hand, in a structure in which the data driver integrated circuit and the gate driver integrated circuit are connected to the thin film transistor substrate and the printed circuit board through the transfer film, an integrated circuit is provided on the transfer film between the pads formed on the thin film transistor substrate and the substrate to be connected. The mounting space is required to increase the size, and there is a disadvantage in that a poor contact occurs when the integrated circuit is attached on the transfer film.

In order to solve this disadvantage, a structure of a chip on glass (COG) type in which a data driving integrated circuit and a gate driving integrated circuit are directly mounted on a thin film transistor substrate is used.

When the integrated circuit is mounted in such a COG type structure, the lead of the integrated circuit is placed on a conductive material (or anisotropic conductive film) positioned on a pad formed on the substrate, and then bonding is performed using the ACF. As a result, the conductive balls contained in the conductive paste are broken, and conduction occurs between the pads on the substrate and the integrated circuit, thereby enabling signal transmission.

However, in this bonding process, a contact resistance occurs between the integrated circuit and the pad, and the magnitude of the contact resistance is not known, so it is not possible to confirm whether a signal is normally transferred between the integrated circuit and the pad on the substrate. In particular, when the screen is configured using a plurality of integrated circuits, the magnitude of the signal transmitted to each integrated circuit is different due to the contact resistance, and thus there is a problem that a deviation occurs on the reproduced screen.

Therefore, the technical problem to be achieved by the present invention is to easily measure whether the bonding is normally performed when bonding between the devices for signal connection in the liquid crystal display device.

In order to solve the above technical problem, in the liquid crystal display according to the aspect of the present invention, a plurality of gate lines and data lines are formed in row and column directions, respectively, and the gates are respectively defined in regions defined by intersections of the gate lines and data lines. A substrate including a pad unit having a plurality of pixels having switching elements connected to a line and a data line, the pad unit having a plurality of pads for signal transmission to one side of each gate line and data line; A gate driver supplying a gate driving signal to the gate line; And a data driver for supplying an image data signal to the data line, wherein the gate driver and the data driver are connected to a pad part on the substrate and are provided on a transfer film for transmitting a signal to the gate line and the data line. The pad unit further supplies a corresponding signal, and the pad unit further includes a monitoring window made of a transparent material in which a part of the region is checked to bond the conductive film to the transfer film using the conductive material. .

In the liquid crystal display according to another aspect of the present invention, a plurality of gate lines and data lines are formed in row and column directions, respectively, and are connected to the gate lines and data lines in regions defined by intersections of the gate lines and data lines, respectively. A substrate including a pad unit having a plurality of pixels having a switching element, the pad unit having a plurality of pads for signal transmission to one side of each gate line and a data line; A gate driver supplying a gate driving signal to the gate line; And a data driver for supplying an image data signal to the data line, wherein each signal terminal of the gate driver and the data driver is bonded to the pad part on the substrate through a conductive material containing conductive particles and mounted on the substrate. The pad part may further include a monitoring window made of a transparent material in a part of the area so as to check the deformation state of the conductive particles when bonding the conductive part including the conductive film.

In the liquid crystal display having the above characteristics, the monitoring window includes a first monitoring window located at a first point of the pad part and a second monitoring window located at a second point of the pad part.

In addition, according to another aspect of the present invention, a method of measuring a bonding state in manufacturing a liquid crystal display device includes a plurality of gate lines and data lines formed in rows and columns, respectively, in regions defined by intersections of the gate lines and data lines. A plurality of pixels having a switching element connected to the gate line and the data line are formed, and a liquid crystal including a substrate including a pad unit having a plurality of pads for signal transmission to one side of each gate line and data line. A method of bonding a gate driver for supplying a gate driving signal to the gate line and a data driver for supplying an image data signal to the data line in a display device, the method comprising: forming a monitoring window on the pad part in which a region is made of a transparent material Doing; After the conductive material including the conductive particles is positioned on the pad part, a wire is formed to be connected to each signal terminal of the gate driver and the data driver, and a pad for connecting the pad part on the substrate is formed for each wire. Bonding the transfer film on the conductive material to perform bonding; And determining whether the bonding is normally performed by checking the deformation state of the conductive particles generated during the bonding through the transparent area of the monitoring window of the pad unit.

Here, the judging step determines whether the bonding is normally performed based on the deformation state of the conductive particles and the number of the deformed conductive particles confirmed through the monitoring window.

In addition, according to another aspect of the present invention, a method of measuring a bonding state in manufacturing a liquid crystal display device includes a plurality of gate lines and data lines formed in rows and columns, respectively, in regions defined by intersections of the gate lines and data lines. A plurality of pixels having a switching element connected to the gate line and the data line are formed, and a liquid crystal including a substrate including a pad unit having a plurality of pads for signal transmission to one side of each gate line and data line. A method of bonding a gate driver for supplying a gate driving signal to the gate line and a data driver for supplying an image data signal to the data line in a display device, the conductive material including conductive particles in the pad part. Positioning the; Positioning and bonding each signal terminal of the gate driver and the data driver to correspond to each pad of the pad part; Selecting a terminal to which the same signal is input from among the signal terminals of the gate driver and the data driver; Measuring contact resistances between the terminals of each of the selected driving units and pads of the pad unit bonded corresponding to the terminals; And determining whether bonding between the driving unit and the pad unit is normally performed based on the measured contact resistance.

Here, the contact resistance measuring step selects two terminals connected to each other in each driving unit, and then measures contact resistance between the selected terminal and pads of the pad unit bonded to the selected terminal, respectively.

In addition, in the bonding state determination step, it may be determined that the bonding is normally performed when the contact resistance measured between the selected terminal and the pad is the same.

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

First, a description will be given of measuring whether bonding is normally performed when bonding chips in a liquid crystal display device having a COG structure.

1 illustrates a schematic planar structure of a COG type liquid crystal display device according to a first exemplary embodiment of the present invention, and FIG. 2 schematically illustrates a structure of a pad part formed on the thin film transistor substrate illustrated in FIG. 1. have.

In the liquid crystal display according to the first exemplary embodiment of the present invention, a plurality of integrated circuits, for example, a data driver 11, are formed at edge portions of the thin film transistor substrate 100 bonded to the color filter substrate constituting the LCD panel 110. 1n) and a plurality of gate drivers 21-2m are located.

The thin film transistor substrate 100 includes a plurality of gate lines 111 and data lines 112, and a plurality of pad portions P1 to Pn are formed at one end of each line as shown in FIG. 2. In FIG. 2, only a pad portion connected to a gate line or a data line is briefly illustrated.

As illustrated in FIG. 2, a plurality of pads are formed in each pad portion P1 to Pn to be connected to each lead terminal of one driving unit (gate driving unit or data driving unit), and each pad may include a gate line (or data). Line).

Accordingly, the data driver and the gate driver are bonded to the pad parts P1 to Pn formed on the thin film transistor substrate 100 as shown in FIG. 2 by a thermocompression bonding process.

In the liquid crystal display device having such a structure, the contact resistance generated by the bonding is measured so that a signal is uniformly transmitted between each driver and the pad portion on the substrate.

3 illustrates a structure for measuring contact resistance generated after bonding the driving unit with the pad on the substrate.

There is a signal connected to each other in the chip, that is, the driver. For example, ground terminals are connected to each other, and terminals to which the same signal is input are connected to each other. Therefore, in the first embodiment of the present invention, two terminals to which the same signal is input are selected from among the plurality of terminals of the driving unit.

As shown in FIG. 3, a connection resistance Rin exists between two selected terminals to which the same signal is input, and generally has a low value that can be ignored.

Each lead of the driver is connected to each pad of the pad part for signal transmission of each data line or gate line formed on the thin film transistor substrate 100. Specifically, a conductive material containing conductive balls or the like is attached to each lead of the driving unit to form bumps of the driving unit, and bonding the bumps of the driving unit and the pads on the substrate 100 with pressure and heat using an ACF. Let's do it. As a result, the conductive balls of the bumps are broken so that conduction is formed to transmit signals between the driver and the pads on the substrate. At this time, the contact resistance is generated according to the bonding between the bump of the driving unit and the pad on the substrate. If the conductive ball is not broken, the contact resistance is large, and if the conductive ball is broken normally, the contact resistance is small.

As described above, in order to bond each driving unit to the substrate 100 and check whether the bonding is performed correctly for each driving unit, as shown in FIG. 3, a lead, that is, a terminal through which the same signal is transmitted, is selected. The contact resistances R1 and R2 are respectively measured by connecting a resistance meter (not shown) to both ends of the pads P11 and P1n on the substrate connected to the bumps B1 and B2 of the selected terminal.

The contact resistance R1 measured between the bump B1 of the first terminal and the corresponding pad P11 of the substrate connected and the contact measured between the corresponding pad P1n of the substrate connected with the bump B2 of the second terminal By comparing the resistance (R2) value, it is determined that the signal distortion occurs between terminals to which the same signal should be transmitted when the measured deviation value of the resistance value is more than the minimum value. It is determined that the signal is not transmitted because it is not broken. When the signal is not transmitted, the contact resistance between the corresponding terminal and the pad becomes very large, and thus the bonding state between the terminal and the pad can be determined based on the resistance value. In addition, by measuring the contact resistance between the terminals to which the same signal is transmitted, it is possible to determine the signal transmission state more accurately.

Based on the determination result, the resistance variation between the driving units can be made small so that abnormalities such as image quality variation for each specific region can not be issued. This contact resistance measurement is the same as the contact resistance measurement generated when bonding the terminal and the pad of the driving unit as described above, in addition to the contact resistance measurement occurring when the terminal of the driving unit is bonded on the PCB substrate or when bonding the FPC. Can be applied.

Meanwhile, the bonding state may be determined by monitoring the state of the conductive ball broken during bonding.

Next, a second embodiment of the present invention for determining the bonding state by monitoring the deformation state of the conductive ball will be described.

The liquid crystal display according to the second embodiment of the present invention may be a COG type liquid crystal display device as in the first embodiment, and a TCP (tape carrier package) in which the driving unit is connected to the pad unit on the substrate by FPC. Type liquid crystal display device.

Herein, the case where the pad portion on the substrate is bonded to the FPC in the TCP type liquid crystal display will be described as an example. However, the present invention is not limited thereto, and the same applies to the case where the driving portion is bonded to the pad portion on the substrate in the COG type liquid crystal display. Can be applied.

4 illustrates a pad portion structure of the liquid crystal display for determining a bonding state according to the second embodiment of the present invention.

In the second embodiment of the present invention, monitoring windows M1 and M2 are formed in each pad portion formed on the thin film transistor substrate in order to monitor the conductive balls whose state is deformed during bonding. In FIG. 4, only one pad part structure is enlarged.

Specifically, as shown in FIG. 4, in the second embodiment of the present invention, the pad portion P1 to which a plurality of gate lines or data lines are connected is a plurality of pads p11 to p1n to be connected to each pad of the FPC. Are formed, and monitoring windows M1 and M2 for monitoring the conductive balls are formed on the left and right sides of the plurality of pads p11 to p1n.

Each of the pads P11 to p1n and the monitoring windows M1 and M2 is made of metal, but the monitoring windows M1 and M2 are made of a transparent metal in a predetermined area. That is, in order to monitor the conductive balls, a certain area, for example, a center area of the monitoring windows M1 and M2 is formed of a transparent electrode.

As described above, each pad portion on the thin film transistor substrate includes a monitoring window. Then, an anisotropic conductive film is placed on each pad portion having such a structure, and then the FPC having the pad as shown in FIG. The pads are positioned to correspond to the pads of the pads. Next, when the FPC is pressed using a crimping head (not shown), the conductive ball contained in the anisotropic conductive film positioned between the pad portion on the substrate and the FPC is broken to enable signal transmission between the pad portion and the pad of the FPC. In addition, pressure is applied between the monitoring window formed on both sides of the pad portion and the FPC, so that the conductive ball is broken.

At this time, the breaking state of the conductive ball may vary according to the compression between the pad part and the FPC. For example, in order to form a conduction between one pad, the conductive ball may be broken even if the conductive ball is broken more than a set number. Even if this broken or the conductive ball is broken, a defect may occur such that the shape does not become a form capable of forming a conduction.

In particular, when the pressure applied to the pad portion is uniform, the pressure applied to each pad and the pressure applied to the monitoring windows formed on the left and right sides of the pad portion are the same, but the pressure applied to the left and right sides is not equal due to the failure of the pressure process. May occur. Therefore, the deformation state of the conductive ball according to the pressure applied to the monitoring windows M1 and M2 through the transparent areas of the monitoring windows M1 and M2 is measured to determine whether the pressing process is normally performed.

That is, when the deformation state of the conductive ball confirmed through the monitoring window M1 formed on the left side of the pad portions p11 to p1n and the deformation state of the conductive ball confirmed through the monitoring window M2 formed on the right side are not the same. In this case, it is determined that the crimping process is not performed normally, and when the number of broken conductive balls measured through the left and right monitoring windows M1 and M2 is different from each other, it is determined that the pressure is not uniformly applied. .                     

Further, although pressure is uniformly applied to the pad portion, the pressure applied may be less than the set pressure. In this case, the number of broken conductive balls measured on the left or right monitoring window of the pad part is compared with the set number, and when it is smaller than the set number, it is determined that the bonding process is not performed normally because a pressure lower than the set pressure is applied.

As described above, according to the second embodiment of the present invention, after bonding between the pad portion of the thin film transistor substrate and the FPC without using a separate device, it is immediately possible to check whether the corresponding bonding process is normally performed. .

On the other hand, in the COG type liquid crystal display device, as described above, a monitoring window is formed on each pad portion on the substrate, and a bonding process is performed by compressing the driving units, and then bonding between the driving unit and each pad unit is performed through the monitoring window. It can be easily confirmed whether it was made normally. Forming the monitoring window in the liquid crystal display of the COG type can be easily devised through the above second embodiment, and thus a detailed description thereof will be omitted.

The invention is susceptible to various modifications and implementations without departing from the scope of the following claims.

As described above, according to the present invention, when bonding is performed for signal connection at the time of manufacturing a liquid crystal display, it is easy to measure whether bonding is normally performed.

In particular, in manufacturing a liquid crystal display device having a COG structure, contact resistance generated during bonding between each driving integrated circuit and a pad on a substrate can be easily measured, and bonding is normally performed based on the measured contact resistance value. It can be easily determined that the signal transmission is performed correctly.

In addition, by forming a monitoring window having a transparent area on the pad portion on the substrate and bonding between the pad portion of the thin film transistor substrate and the FPC or the driving integrated circuit without using a separate device, the bonding process is performed normally. You can check immediately.

Claims (8)

delete delete delete delete delete A plurality of gate lines and data lines are formed in row and column directions, respectively, and a plurality of pixels having switching elements connected to the gate lines and data lines are formed in regions defined by intersections of the gate lines and data lines. And a gate driver for supplying a gate driving signal to the gate line in a liquid crystal display including a substrate including a pad unit having a plurality of pads connected to one side of each gate line and a data line for signal transmission. In the method of bonding a data driver for supplying a data signal to the pad portion, Positioning a conductive material including conductive particles in the pad part; Bonding each signal terminal of the gate driver and the data driver to correspond to each pad of the pad part; Selecting a terminal to which the same signal is input from among the signal terminals of the gate driver and the data driver; Measuring contact resistances between the terminals of each of the selected driving units and pads of the pad unit bonded corresponding to the terminals; And Determining whether bonding between the driving unit and the pad unit is normally performed based on the measured contact resistance; Bonding state measurement method at the time of manufacturing a liquid crystal display containing a. The method of claim 6, In the step of measuring the contact resistance, when selecting two terminals connected to each other in each driving unit, and then manufacturing a liquid crystal display device for measuring the contact resistance between the selected terminal and the pad of the pad unit bonded corresponding to the selected terminal. How to measure the bonding state of The method of claim 6, The bonding state determination step A method of measuring bonding state at the time of manufacturing a liquid crystal display device in which it is determined that the bonding is normally performed when the contact resistance measured between the selected terminal and the pad is the same.

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