KR20080059836A - Cof and lcd with the same - Google Patents

Abstract

An COF(Chip On Flexible printed circuit) and an LCD(Liquid Crystal Display) having the same are provided to buffer mechanical impacts applied from the outside by forming holes in both sides where an output pad is patterned, thereby preventing cracks from being generated in an electrode pattern configuring the output pad and accordingly manufacturing a reliable LC panel. A film(102) has a predetermined shape. An input pad(IP) is patterned in one side and the other side of the film, and configured in a location corresponding to an output pad(OP) comprising plural electrode patterns(104b) contacted with a pad unit of a display device. The input pad comprises plural electrode patterns(104a). A driving IC(Integrated Circuit)(106) is simultaneously connected to one side and the other side of the output pad and the input pad. Impact buffering holes(110a,110b) are formed according as one side and the other side of the film, where the output pad is located, are recessed.

Description

OSF and LCD including the same. {COF and LCD with the same}

1 is a perspective view schematically showing a liquid crystal display device;

2 is a schematic plan view of a liquid crystal panel in which a driving circuit is mounted;

Figure 3a is a plan view schematically showing a conventional COF, Figure 3b is a schematic cross-sectional view of the COF of Figure 3a

4 is a cross-sectional view showing a state in which a conventional COF is attached to a liquid crystal panel,

5 is a photograph of the electrode pattern of the COF in which the actual crack occurred,

6 is a plan view schematically showing a COF according to the present invention;

7 is a plan view schematically illustrating a state in which a COF is attached to a liquid crystal panel according to the present invention.

<Brief description of the main parts of the drawing>

102 film 104a, 104b electrode pattern

106: driving IC chip 110a, 110b: shock mitigation hole

IP: Input Pad OP: Output Pad

The present invention relates to a display element, and more particularly, to a chip on flexible printed circuit (COF) which is a driving IC package attached to the display element.

In general, a display device such as a semiconductor device or a liquid crystal display device is manufactured to be thin and thin for small size and light weight.

At this time, the semiconductor device or the display device is a small drive circuit packaged of a TCP type (tape carrier package type) or COF type (chip on film).

Hereinafter, the driving circuit will be described with reference to a liquid crystal display device among display elements.

1 is a view schematically showing a liquid crystal display device.

As shown in the drawing, the liquid crystal display device 30 is transparent in common on the black matrix 6 and the color filters (red, green, blue) 7a, 7b, and 7c, and the color filters 7a, 7b, and 7c. An upper substrate 5 having electrodes 9 formed thereon, and a lower substrate 10 having array wirings 26 and 24 including pixel regions P and pixel electrodes 32 and switching elements T formed on the pixel regions. And a liquid crystal 14 is filled between the upper substrate 5 and the lower substrate 10.

The lower substrate 10 is also referred to as an array substrate, and the thin film transistor T, which is a switching element, is positioned in a matrix type, and includes a gate wiring 24 and a data wiring 26 passing through the plurality of thin film transistors. Is formed.

The pixel area P is an area defined by the gate line 24 and the data line 26 intersecting with each other. The pixel electrode 32 formed on the pixel region P uses a transparent conductive metal having relatively high light transmittance, such as indium-tin-oxide (ITO).

In this case, a scanning signal flows through the gate wire 24, a data signal flows through the data wire 26, and the image signal is transferred to the pixel electrode 32 according to the scan signal. To flow.

Accordingly, an electric field is generated between the pixel electrode 32 and the common electrode 9 through which the common signal flows, thereby driving the liquid crystal 14 to display an image.

Meanwhile, a signal flowing through the gate line 24 and the data line 26 is input from an external driving system (not shown). At this time, a signal is transferred between the external driving system (not shown) and the liquid crystal panel 30. A drive circuit (not shown) is configured.

This will be described below with reference to FIG. 2.

2 is a schematic plan view of a liquid crystal panel in which a driving circuit is mounted.

As shown, the liquid crystal panel 30 is configured by bonding the first substrate 10 and the second substrate 5,

As described above, the lower substrate 10, which is the first substrate, includes a plurality of signal wirings (not shown) configured to cross each other and a switching element (not shown) and a pixel electrode (not shown) connected thereto at the intersection points. .

The data pad part A and the gate pad part B are formed at one side of the liquid crystal panel 30 and the other side not parallel thereto. Each of the pad parts A and B includes a plurality of pad electrodes that are ends of the data line (FIG. 1 26) and the gate wiring (24 of FIG. 1).

In general, when the active layer of the switching element included in the lower substrate 10 is formed of an amorphous silicon (a-Si: H) layer, a separate driving circuit 36 is required. ) Is representatively a packaged driving circuit of the TCP or COF type.

The TCP or COF type driving circuit 36 attaches one side of the film 40 having the IC chip 38 to the pad electrode (not shown), and to the other side of the IC chip 38. The PCBs 42a and 42b are attached to transfer the signals input from the PCBs 42a and 42b to the liquid crystal panel 30.

In the above-described configuration, the PCB substrate 42a positioned corresponding to the data pad portion A has a larger area than the PCB substrate 42b positioned corresponding to the gate pad portion B.

This is because most of the other driving circuits are mounted on the PCB board 42b formed in the data pad part A.

Each of the PCB substrates 42a and 42b described above uses a drive circuit 36 of a TCP type (hereinafter referred to as "TCP") or a COF type (hereinafter referred to as "COF") using a film of a flexible polymer material. Since it is used, it can be turned over to the back of the liquid crystal panel 30.

In particular, the COF is widely used because it is flexible and inexpensive as compared with the TCP, because of the thinness and shortness and the file pitch.

Hereinafter, the planar configuration and cross-sectional configuration of a conventional COF will be described in detail with reference to FIGS. 3A and 3B.

3A is a plan view schematically illustrating a conventional COF, and FIG. 3B is a cross-sectional view taken along line IV-IV of FIG. 3A.

As shown, COF (Chip on film, 50) is different from TCP because it employs a thin film (thin film) (60) further uses a separate support film 62.

That is, as shown, the support film 62 is attached to the lower portion of the thin film 60, the electrode pattern 72 is formed of a copper foil pattern through an adhesive (64).

The electrode pattern 72 is formed of a plurality of positions symmetrical to each other on one side and the other side of the thin film 60, each referred to as an input pad (IP) and an output pad (OP).

The input pad IP contacts the PCB substrates 42a and 42b described above, and the output pad OP contacts the pad portion of the liquid crystal panel 30 of FIG. 2.

At this time, unlike the TCP, the COF 50 does not form a separate opening, and directly mounts the IC chip 66 on the surface of the thin film 60.

The terminal 68 of the IC chip and the electrode patterns 72 which are the input pads and the output pads IP and OP are in contact with each other, and the contact portion is sealed with the polymer resin 70.

The COF configured as described above is attached to the liquid crystal panel and used.

Hereinafter, the cross-sectional structure of the liquid crystal panel with COF will be described with reference to FIG. 4.

4 is a cross-sectional view illustrating a state in which a conventional COF is attached to a liquid crystal panel, and FIG. 5 is a view showing a photograph of an electrode pattern of a COF in which an actual crack occurs.

As shown, the COF 50 is attached to one side of the liquid crystal panel 30 through a conductive adhesive, that is, ACF (80).

At this time, the liquid crystal panel 30 is a form in which the array substrate B2 and the color filter substrate B1 are adhered through the adhesive 84 with the liquid crystal layer LC therebetween, and the array substrate B2 is a signal. The pad unit A for receiving the input is manufactured in a form exposed to the outside of the color filter substrate B2.

A plurality of pads 86 configured in the pad part A receive a signal from the external PCB substrate (not shown) through the COF 50.

Accordingly, as shown in the drawing, one side and the other side of the COF 50 simultaneously contact the pad portion A of the liquid crystal panel and the electrode patterns of the PCB substrate (42a and 42b of FIG. 2) through the conductive adhesive 80 at the same time. It is composed.

At this time, since the COF 50 is flexible, it is possible to pass the PCB substrate (42a, 42b of FIG. 2) in contact with the rear side of the liquid crystal panel to fix it.

However, as shown in FIG. 5, the conventional COF has a much thinner thickness of the copper foil, which is the electrode pattern 64, than the TCP, so that the cracks C may be formed on the copper foil due to mechanical shock generated during the assembly process or mechanical reliability test. There is a disadvantage that occurs easily.

5, it can be seen that cracks C occur in one direction in the electrode patterns 64.

However, cracks generated in the plurality of electrode patterns 64 may occur in an area 200 μm above and below the boundary portion (SR line) between the exposed portion of the output pad OP and the unexposed portion (insulation portion). do. That is, mainly occurs in the region F of FIG.

That is, the portion F in which the crack occurs is an output pad OP in contact with the liquid crystal panel, and corresponds to a range of 200 μm up and down from the center of the output pad OP.

As such, signal defects may occur due to cracks in the electrode pattern, which may lower the reliability of the liquid crystal panel.

The present invention has been proposed to solve the above-described problem, and has as its first object to propose a COF structure in which cracks do not occur.

The second object is to produce a highly reliable liquid crystal panel by employing COF in which cracks do not occur.

COF according to the present invention as described above is a film of a predetermined shape; An output pad patterned on one side and the other side of the film, the output pad including a plurality of electrode patterns in contact with the pad portion of the display element, and an input pad configured at a position symmetrical thereto; A driving IC connected to one side and the other side of the output pad and the input pad simultaneously; It includes a shock-absorbing hole formed by inserting one side and the other side of the film in which the output pad is located.

The plurality of electrode patterns forming the output pad and the input pad may be a thin copper foil pattern.

The hole is characterized in that the semicircular shape.

A liquid crystal display according to the present invention includes a liquid crystal panel including a color filter substrate and an array substrate bonded to the color filter substrate in a form in which a pad part is exposed to the outside; An output pad bonded to the pad portion of the liquid crystal panel and composed of a plurality of electrode patterns, an input pad corresponding to and positioned in contact with the pad portion of the liquid crystal panel, a driving IC simultaneously in contact with the output and the input pad, An input pad and a driving IC, the COF including a shock-absorbing hole formed by inserting one side and the other side of the film in which the output pad is located; and a PCB substrate attached to the input pad of the COF. It is done.

The hole is characterized in that the end of the liquid crystal panel is configured on both sides of the film intersect.

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

Example

6 is a plan view schematically showing a COF according to the present invention.

As shown, the COF 100 according to the present invention is a rectangular film 102 composed of a thin film and a support film, and a plurality of electrode patterns 104a on one side and the other side of the rectangular film 102, respectively An input pad OP composed of 104b and a plurality of output pads IP are configured.

An IC chip 106 is formed at the center of the rectangular film 102, and a plurality of connection terminals positioned at one side and the other side of the IC chip 106 are respectively the input pad IP and the output pad OP. Contact with the plurality of electrode patterns 104a and 104b belonging to

The output pad OP is a part in contact with a pad portion (not shown) of the liquid crystal panel, and the input pad is in contact with an external PCB (not shown).

At this time, the shock-absorbing holes (semi-circular shape, 110a, 110b) are formed on both sides of the film 50 in which the output pad OP in contact with the liquid crystal panel is characteristic.

The light alleviating holes 110a and 110b are formed at one side and the other side of the rectangular film 102, and in particular, a portion corresponding to the center area of the output pad OP is inserted into the shape. It features. Accordingly, the shapes of the holes 110a and 110b may be mainly formed in semicircular shapes.

As described above, when the COF 100 having the shock-absorbing holes 110a and 110b is attached to the liquid crystal panel (not shown) on both sides, even if an impact is applied to the liquid crystal panel (not shown) in various situations, the hole is provided. Since the mechanical shock applied by the damper is alleviated, no severe shock is transmitted to the electrode pattern 104b constituting the output pad OP.

Therefore, there is an advantage in that a crack may be prevented from occurring in the electrode pattern 104b.

A description with reference to FIG. 7 is as follows.

7 is a plan view schematically illustrating a state in which a COF is attached to a liquid crystal panel according to the present invention.

FIG. 7 illustrates a small liquid crystal panel different from FIG. 2 and a COF attached thereto, wherein the color filter substrate 150 and the array substrate 152 are bonded to each other, and an exposed pad portion of the array substrate 152 is illustrated. The output pad 162 of the COF 160 is attached to (G) with ACF, which is a conductive adhesive.

At this time, even when a mechanical shock is applied during assembly or testing of the module, the impact can be alleviated by the impact mitigating holes 164a and 164b introduced into both sides of the output pad. There is an advantage that the crack does not occur in the electrode pattern to form.

As described above, the COF according to the present invention forms holes on both sides of which the output pads are patterned, thereby alleviating mechanical shock applied from the outside, so that cracks do not occur in the electrode pattern forming the output pads. There is an effect that can produce a liquid crystal panel.

In addition, since there is no crack in the output pad, there is an effect of reducing the defects and improving productivity and saving costs.

Claims (7)

A film of a predetermined shape; An output pad patterned on one side and the other side of the film, the output pad including a plurality of electrode patterns in contact with the pad portion of the display element, and an input pad configured at a position symmetrical thereto; A driving IC connected to one side and the other side of the output pad and the input pad simultaneously; Impact buffer hole formed by inserting one side and the other side of the film in which the output pad is located C0F comprising a. The method of claim 1, The plurality of electrode patterns constituting the output pad and the input pad is a thin copper foil pattern. The method of claim 1, The hole is characterized in that the semi-circular COF. A liquid crystal panel comprising a color filter substrate and an array substrate bonded to the color filter substrate in a form in which a pad part is exposed to the outside; An output pad bonded to the pad portion of the liquid crystal panel and composed of a plurality of electrode patterns, an input pad corresponding to and positioned in correspondence with the pad portion of the liquid crystal panel; An input pad and a driving IC, and a COF including a shock-absorbing hole formed by inserting one side and the other side of the film on which the output pad is located; PCB board attached to the input pad of the COF Liquid crystal display comprising a. The method of claim 4, wherein And a plurality of electrode patterns forming the output pad and the input pad are thin copper foil patterns. The method of claim 4, wherein The hole is a semi-circular liquid crystal display device characterized in that. The method of claim 4, wherein And a hole is formed at both sides of the film where the ends of the liquid crystal panel cross each other.

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