KR20040087452A - Liquid crystal display module - Google Patents

Abstract

PURPOSE: An LCD(Liquid Crystal Display) module is provided to prevent that picture quality is degraded by resistance difference between fan-out lines. CONSTITUTION: A plurality of fine holes(57) are formed in a pad to expose a bottom metal(53) to a protective film(51). An ITO(Indium Tin Oxide) pattern(59) is formed on the protective film to be contacted with bottom metal parts exposed through the fine holes. The number of the fine holds are increased from a pad connected with the shortest fan-out line to a pad connected with the longest fan-out line. The number of conductive balls in an ACF(Anisotropic Conductive Film) inserted between the pad and the TCP pattern exists more in the pad connected with the longest fan-out line than the pad connected with the shortest fan-out line.

Description

Liquid crystal display module

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a liquid crystal display module, and more particularly, to a pad structure in a liquid crystal panel for preventing deterioration of screen quality due to a difference in resistance of a fan-out line.

In general, an LCD module includes a liquid crystal panel (LC panel) in which a lower substrate and an upper substrate displaying an image are bonded to each other under an intervening liquid crystal layer, and a PCB for applying a predetermined image signal to the liquid crystal panel. Printed Circuit Board (hereinafter, referred to as PCB) and a Tape Carrier Package (TCP) for electrically connecting the liquid crystal panel and the PCB.

Here, the PCB typically includes a gate PCB connected with the gate pads and a data PCB connected with the data pads. Recently, the gate PCB has been omitted.

In the TCP, a drive film IC is mounted on a flexible film, and several leads connected to the drive drive IC are arranged on both sides of the film, and the TCP is a tab (TAB). Tape Automated) bonding, that is, the pad of the liquid crystal panel and the electrode of the PCB by a method of thermocompression bonding TCP through an anisotropic conductive film having a plurality of conductive balls therein (hereinafter referred to as ACF). Terminals and TCP are each electrically connected by conductive balls.

1 is a plan view illustrating a conventional liquid crystal display module without a gate PCB.

As shown, a source PCB 15 for applying a predetermined image signal is disposed above the liquid crystal panel 10, and electrode terminals (not shown) of the PCB 15 and the liquid crystal panel 10 are disposed. The data pads (not shown) disposed at the upper edge of the lower substrate 1 of the lower substrate 1 are electrically connected by tap bonding using the TCP 13 mounted with the drive drive IC 11.

However, the above-described conventional liquid crystal display module has a problem in screen quality for the following reasons.

In general, several pads having the same pitch on one side and the upper edge of the lower substrate are arranged in a row at regular intervals, and each gate and data line and a fan-out line of the display unit arranged in a matrix form are arranged. Is connected through. Here, the fan-out line is not formed separately, but merely names the gate and data line portions disposed between the pad portion and the display portion.

However, when TCP is tab bonded to such a pad structure, as shown in FIG. 2, routing lines respectively connected to the pad 20a disposed in the middle and the pad 20n disposed at the outermost portion, that is, The resistance is more than doubled between the fan-outlines 25a and 25n, and the difference in resistance becomes more serious when applied to a high-definition product. In the end, the liquid crystal panel shows a block. The display quality is poor because different luminance is displayed in units of).

FIG. 3 is a cross-sectional view illustrating a pad structure in a conventional liquid crystal panel. As shown in FIG. 3, the pad 30 has a pixel on a bottom metal layer 33 which is a gate or data line metal exposed by opening the passivation layer 35. An ITO pattern 39, which is an electrode material, is contacted.

In FIG. 3, reference numeral 31, which is not described, denotes a lower substrate, and 37, a hole.

Accordingly, an object of the present invention is to provide a liquid crystal display module which is designed to solve the above problems, and to prevent deterioration of screen quality due to a difference in resistance between fan-out lines.

1 is a plan view showing a conventional liquid crystal display module.

2 is an enlarged plan view corresponding to part A of FIG. 1;

3 is a cross-sectional view illustrating a pad structure in a conventional liquid crystal panel.

4 is a plan view illustrating a pad unit in a liquid crystal display module according to an exemplary embodiment of the present invention.

5 is a cross-sectional view illustrating a pad structure in a liquid crystal panel according to the present invention.

6 is a plan view for comparing and explaining the pad structure in the liquid crystal panel according to the prior art and the present invention.

Explanation of symbols on the main parts of the drawings

40, 50: Pad 44a to 44n: Fan-out line

49,59: ITO pattern 51: lower substrate

53: bottom metal 55: protective film

57: fine hole

In order to achieve the above object, the present invention is anisotropic having a plurality of conductive balls therein between the pads of the liquid crystal panel and the electrode terminals of the PCB arranged in a row spaced apart at regular intervals of several pieces having the same pitch In the liquid crystal display module electrically connected to each other by thermal bonding of TCP under the conductive film, a plurality of fine holes are formed on the pad to expose the bottom metal to the passivation layer, and are exposed through the fine holes on the passivation layer. The ITO pattern is formed to be in contact with the bottom metal parts, and the fine holes exposing the bottom metal have the shortest fan- such that the resistance difference according to the length between the fan-out lines disposed between the pad and the display part is minimized. The number of pads connected to the line from the pad to the longest fan-out line is increased so as to increase the number It provides a liquid crystal display module.

Here, the number of conductive balls in the anisotropic conductive film interposed between the pad and the TCP is greater in the pad connected with the longest fan-out line than in the pad connected with the shortest fan-out line.

According to the present invention, by controlling the number of holes exposing the bottom metal, when the electrical connection by the anisotropic conductive film having a conductive ball and the TCP is made, the number of conductive balls interposed between the pad and the TCP can be adjusted, Accordingly, the difference in resistance according to the length between the fan-out lines can be minimized, so that a good display quality of the liquid crystal panel can be obtained.

(Example)

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

4 is a plan view illustrating a pad unit in a liquid crystal display module according to an exemplary embodiment of the present invention, FIG. 5 is a cross-sectional view illustrating a pad structure in a liquid crystal panel according to the present invention, and FIG. It is a top view for comparing and explaining the pad structure in the liquid crystal panel which concerns.

Referring to FIG. 4, the liquid crystal display module of the present invention has a resistance according to the length of the routing line, that is, the fan-out lines 44a to 44n, in which the pads 40 in the liquid crystal panel are disposed between the pad and the display unit. The contact area between the bottom metal (not shown) and the ITO pattern 49 has a structure different from each other so as to minimize the difference.

That is, in the design of the pad in the liquid crystal panel, each pad 40 forms a plurality of fine holes to expose the bottom metal in the passivation layer, and then the bottom metal exposed through the fine holes on the passivation layer. The ITO pattern 49 is formed to be in contact with the portions, and the number of the fine holes increases from the pad connected with the shortest fan-out line 44a to the pad connected with the longest fan-out line 44n. Form.

In other words, as shown in FIG. 5, in the pad according to the present invention, a plurality of fine holes 57 are formed in the passivation layer 55 to expose the bottom metal 53, and the passivation layer 55 is formed on the passivation layer 55. The ITO pattern 59 is formed to contact the bottom metal 53 through the fine holes 57.

Accordingly, in the conventional pad 30, the bottom metal 33 is exposed by a single hole 37 as shown in the left figure of FIG. 6, and the ITO pattern (not shown) is contacted through the hole 37. However, the pad 50 according to the present invention has an ITO pattern contacted through the holes 57 where the bottom metal 53 is exposed by the plurality of micro holes 57, as shown in the right figure of FIG. 6. You have a structure.

In this case, as the number of the fine holes is adjusted, the contact area between the bottom metal and the ITO pattern is different, and in particular, when the TCP is thermocompression-bonded to the pad under the presence of the anisotropic conductive film having conductive balls, As a result, the number of conductive balls that electrically connect the pad and the TCP is different, so the resistance between the pad and the TCP is also different.

As a result, although there may be a difference in the resistance between lines due to the difference in the length between the fan-out lines, the length between the fan-out lines is compensated for by adjusting the number of conductive balls interposed between the pad and the TCP. The difference in resistance due to the difference can be compensated for, so that the difference in resistance between the gate lines and the data lines due to the fan-out line can be minimized, and consequently the resistance between the lines can be kept uniform so that Good screen quality can be obtained.

As described above, the present invention by adjusting the number of the hole while forming a hole to expose the bottom metal to a fine size, it is possible to adjust the number of conductive balls interposed between the pad and TCP, and thus, fan-out By compensating for the difference in resistance between the lengths of the lines by the difference in contact resistance depending on the number of conductive balls interposed between the pad and the TCP, the resistance in each of the lines can be kept relatively uniform, and thus, the liquid crystal panel A good screen quality of can be obtained.

Meanwhile, although specific embodiments of the present invention have been described and illustrated, modifications and variations can be made by those skilled in the art. Accordingly, the following claims are to be understood as including all modifications and variations as long as they fall within the true spirit and scope of the present invention.

Claims (2)

A plurality of pads having the same pitch are spaced at regular intervals and electrically connected to each other by thermally compressing TCP between the pads of the liquid crystal panel arranged in a row and the electrode terminals of the PCB through an anisotropic conductive film having a plurality of conductive balls therein. In the connected liquid crystal display module, The pad has a structure in which a plurality of fine holes are formed to expose a bottom metal on the passivation layer, and an ITO pattern is formed on the passivation layer so as to contact the bottom metal portions exposed through the passage holes. The fine holes exposing the bottom metal are the longest from the pad connected to the shortest fan-out line so that the resistance difference according to the length between the fan-out lines disposed between the pad and the display portion is minimized. The liquid crystal display module, characterized in that the number is formed to increase as the pad connected to the fan-out line. The method of claim 1, wherein the number of conductive balls in the anisotropic conductive film sandwiched between the pad and the TCP is greater in the pad connected to the longest fan-out line than in the pad connected to the shortest fan-out line. Liquid crystal display module characterized in that.