KR19980026755A - Liquid crystal display module - Google Patents

Abstract

The present invention relates to a connection between a liquid crystal display panel and TCP. By widening the width of the portion where the ITO pad and the TAB-IC pad are connected on the liquid crystal display panel to form an OLB pad in a dog-bone form, and arranging the positions of the connection portions in a zigzag shape, the pads are subjected to high resolution in the connection process. Even when the pad size is reduced and the pad pitch is reduced, defects such as a short circuit caused by contact of adjacent pads or an open phenomenon caused by misalignment of the pads can be reduced.

Description

Liquid crystal display module

1 is a cross-sectional view showing an example of mounting a tape carrier package module for a conventional liquid crystal display panel.

2 is a plan view illustrating a connection pad and a TAB-IC pad of a conventional liquid crystal display panel.

3 is a plan view illustrating a connection pad and a TAB-IC pad of a liquid crystal display panel according to an exemplary embodiment of the present invention.

* Description of the symbols for the main parts of the drawings *

2: substrate 4: pad

6: protective film 8: sealing material

10 common electrode 12 black matrix

14 color filter 16 ITO pad

18: anisotropic conductive film 20: drive integrated circuit

22: outer lead (TAB-IC pad) 24: synthetic resin film

26: Tape Carrier Package

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a liquid crystal display, and more particularly, to a junction structure between a liquid crystal display panel and a tape carrier package (TCP) on which a driving integrated circuit is mounted.

As the modern society rapidly develops into an information society, the transmission and processing of information are very important issues. From the point of view of information transfer, the most easily understood by a person is image information transmitted through a screen. Therefore, various apparatuses for transmitting image information are developing, and to date, cathode ray tubes (CRTs) have become mainstream. In addition to cathode ray tubes, thin-film transistor liquid crystal displays, which are recently attracting attention, are applied to personal computers and liquid crystal televisions based on advantages such as thinness, light weight, low power consumption, and delicate image realization.

The physical structure of the thin film transistor liquid crystal display is a form in which a printed wiring board (PCB) and a liquid crystal display panel are connected through a tape carrier package (TCP), and a liquid crystal display panel using a thin film transistor as a switching element is again used. The thin film transistor substrate, the color filter substrate, and the liquid crystal material therebetween are broadly classified.

The liquid crystal display configured in this form is converted into a signal input to the TCP through the PCB substrate into a signal enabling the display device to be driven on the driver integrated circuit and driven independently through each pad and terminal formed in the TCP.

In general, the operation of electrically connecting the liquid crystal display panel with the TCP and the PCB is called mounting. First, the connection between the liquid crystal display panel and TCP uses an anisotropic conductive film instead of lead, depending on the specificity of the material and the fixation of the pitch of about 0.2 mm or less. And although the connection of TCP and printed wiring board uses lead, the use of an anisotropic conductive film is anticipated by the trend of the high-definition pitch in the future.

Currently, the mounting method used in the liquid crystal display is divided into a tape automated bonding (TAB) method and a chip on glass (COG) method.

In the TAB connection method, a pattern is designed on a synthetic resin film, and thermal curing of a large-scale integrated circuit thermocompression-bonded to the synthetic resin film is performed to cut the formed TAB tape to an appropriate size to open the electrode portion of the liquid crystal display panel and the electrode portion of the driving integrated circuit. To squeeze. In the TAB method, an anisotropic conductive film is used as a connection material, so that high-density mounting is possible, which is advantageous for miniaturization and light weight of the liquid crystal display device.

The COG connection method mounts the driving integrated circuit directly on the panel of the liquid crystal display without using a tape-carrier. However, there is an advantage in minimizing the mounting area, reducing the cost, and improving the reliability. Since the high level of technology is required to directly connect the circuits, the development of technology for improving the yield is pointed out as a problem.

Next, the liquid crystal display substrate and the connection portion of the TCP mounted in the TAB method will be described in detail with reference to the accompanying drawings.

1 is a cross-sectional view showing an example of mounting by a TAB method of a TCP module for a conventional liquid crystal display panel.

As shown in FIG. 1, the tape carrier package 26 including the outer lead 22 formed on the synthetic resin film 24 and the drive integrated circuit 20 mounted thereon is formed through the anisotropic conductive film 18. As shown in FIG. It is connected to the liquid crystal display substrate 2. A concrete connection portion is an ITO pad 16 patterned on the outer lead 22 and the liquid crystal display substrate 2.

The anisotropic conductive film 18 containing the conductive particles is made of a thermosetting resin to bond the thin film transistor substrate 2 and the tape carrier package 26 to transfer electric signals by moving electric current by the conductive particles therein. Do it.

The liquid path 2 consists of a thin film transistor substrate and the color filter 14 formed on it. In the color filter substrate 14 on which the black matrix 12 and the common electrode 10 are formed, the pad 4 and the protective film 6 made of an organic insulator are sequentially coated on the front surface, and the pad 4 on the top thereof. The ITO pad 16 is connected to the thin film transistor substrate and the encapsulant 8 formed thereon.

In the tape carrier package 26, the driving integrated circuit 20 is positioned at the center of the top surface of the synthetic resin 24 film and connected to the integrated circuit 20 to form a plurality of outer leads 22. ) Is referred to as TAB-IC, and the outer lead 22 at this time is referred to as a TAB-IC pad. In particular, the portion where the TAB-IC pad 22 and the ITO pad 16 of the liquid crystal display panel 2 are connected is referred to as an outer lead bonding (OLB) pad.

FIG. 2 is a plan view showing a conventional OLB pad, and shows section A in detail in the cross-sectional view of the liquid crystal display shown in FIG.

As shown in FIG. 2, the adhesive part of the conventional OLB pad has a rectangular shape.

In such a conventional structure, an anisotropic conductive film is present in a section where two pads overlap and electrical connection is performed at the same time as bonding.

However, in such a structure, as the pad size is reduced due to the high resolution and the pitch between the pads decreases, more precision is required in the correspondence between the ITO pad and the TAB-IC pad during the process, and thus the contact between adjacent pads is required. There is a problem in that a defect such as an open caused by a short phenomenon or misalignment of a pad increases.

SUMMARY OF THE INVENTION An object of the present invention is to solve such a problem and to stabilize the final display characteristics by arranging the connection portions of the ITO pads and the TAB-IC pads of the liquid crystal display substrate and the positions of the connection portions to cross each other.

In the implementation of the liquid crystal display panel module according to the present invention for achieving the above object, the connection portion of the ITO pad or the TAB-IC pad on the liquid crystal display panel is widened so that the final connection portion is dog-bone (dog) after connecting the two pads. It forms the shape of bone) and arranges it by crossing the position of connection part in zigzag form.

In the case of the liquid crystal display module according to the present invention, the liquid crystal display is reduced in defects such as open phenomenon caused by misalignment between the ITO pad on the panel and the TAB-IC pad or short circuit due to contact between adjacent pads.

Next, embodiments of the liquid crystal display according to the present invention will be described in detail with reference to the accompanying drawings so that those skilled in the art may easily implement the present invention.

FIG. 3 is a plan view of the OLB pad connecting portion according to the embodiment of the present invention, which shows the section A in detail in the cross-sectional view of the liquid crystal display mounting shown in FIG.

In the liquid crystal display according to the present exemplary embodiment, the width of the contact surface between the ITO pad 16a and the TAB-IC pad 22a is extended to deform the connection portion of the OLB pad from a rectangle to a dog bone shape. As shown in FIG. 3, when the pad pitch, which is the distance between adjacent pads, is represented by D _P , the width of the pad is represented by D _W , and the width of the pad contacting surface is represented by D _d , the respective line widths are compared. In this case, D _P D _d D _w has a relationship. At this time, since D _P is larger than D _d , the gap is secured so that the contact surface does not overlap with the expanded connection portion of the adjacent line even when the width of the contact surface is extended compared with the conventional one.

In addition, the possibility of the overlap can be further reduced by patterning to intersect the connection sites of the pads.

In addition, since there is a relationship between D _d D _w , even if a misalignment occurs during the patterning of the pad, a process margin of D _d -D _W is secured compared to the conventional one, thereby reducing the open phenomenon between the two pads.

Therefore, in the connection of the OLB pad unit according to the present invention, the width of the contact surface is wider than the width of the pad to form a dog-bone, thereby securing process margins and improving defects.

Claims (6)

A liquid crystal display module comprising a liquid crystal display panel including a plurality of pads and a tape carrier package including a plurality of leads transmitting a driving signal to the liquid crystal display panel, wherein a width of the pad, the lead, and a connection surface is greater than the pad. Liquid crystal display module larger than the width of the pad. In claim 1, The width of the connection surface of the pad and the lead is greater than the width of the lead. In claim 1, And a connection surface of the pad intersects with an adjacent connection surface in a zigzag form. In claim 1, And a width of the connection portion is wider than a pad pitch. In claim 1, The liquid crystal display module of which the width | variety of the connection surface of the pad is larger than the width of the pad. In claim 1, A liquid crystal display module, wherein a width of a connection surface of the lead is larger than a width of the lead.