KR20080001511A - LCD display device - Google Patents

Abstract

The present invention is composed of a liquid crystal panel and a PCB substrate on which a driving circuit for driving the liquid crystal panel is mounted, and one end of which is attached to the liquid crystal panel and the other end of which is attached to and connected to the PCB substrate. It is characterized in that it further comprises a dummy film to increase the adhesion between the COF and the liquid crystal panel and the PCB substrate on the outside.

Description

Liquid crystal display device {LIQUID CRYSTAL DISPLAY DEVICE}

1 is an exploded perspective view showing a conventional liquid crystal display device.

Figure 2a is a plan view showing a connection state of the liquid crystal panel and the driving circuit PCB substrate.

Figure 2b is a cross-sectional view showing a connection state of the liquid crystal panel and the driving circuit board PCB.

3 is a cross-sectional view showing one side of an edge type liquid crystal display device in which each component is assembled;

4 is a cross-sectional perspective view of a partially assembled liquid crystal display device.

5 is a partial cross-sectional perspective view of a partially assembled liquid crystal display device according to an embodiment of the present invention.

In recent years, due to the rapid development of the information and communication field, the importance of the display device for displaying various kinds of information is increasing, and the cathode ray tube, which is one of the existing display devices, has certain limitations. I could not meet. As a flat panel display, a liquid crystal display (LCD), a plasma display panel (PDP), and an electroluminescence display (ELD) have been developed to meet expectations, and research and development are actively conducted. It is becoming.

Among such display devices, the liquid crystal display device is a display device having advantages such as light weight, thinness, and low power. Due to these advantages, the liquid crystal display device is widely used not only for display devices such as notebook computers, but also for desktop computers and large TVs, and the demand for this is continuously increasing.

1 is a perspective view illustrating a conventional liquid crystal display.

As shown in the figure, a liquid crystal display device includes a liquid crystal panel 10 which fills a liquid crystal having optical anisotropy between two substrates, and changes an orientation of the liquid crystal according to an electrical signal to produce an image, and a backlight unit that supplies light to the liquid crystal panel ( 20), a support main (27; main support) for supporting the liquid crystal panel and the backlight unit, a top case (25) for fixing the edge of the liquid crystal panel from above, a liquid crystal panel and the support main, etc. It is configured to include a cover bottom (29; secured from the bottom).

In the liquid crystal panel 10, liquid crystal is injected between the first substrate and the second substrate and liquid crystal is filled between the upper substrate and the lower substrate. Although not shown, a signal line between the data line and the gate line is formed on the first substrate of the liquid crystal panel, and a thin film transistor (TFT), which is a driving element of the liquid crystal, is formed at the intersection of the lines. The data line and the gate line cross each other to form a pixel region, and a pixel electrode is formed in the pixel region. In addition, a pad region for connecting data lines and gate lines, respectively, is formed at one side of the first substrate, and in this pad region, a COF (not shown) in which a driver integrated circuit for applying a driving signal to a thin film transistor is mounted. Circuit On Film: 11) or Tape Carrier Package (TCP) is attached. COF and TCP are a kind of flexible circuit boards in which circuits are mounted on materials such as bendable films. The COF or TCP receives a signal from the PCB substrate 12 on which the liquid crystal driving circuit is mounted and supplies the signal to the data line.

The backlight unit 20 used as a light source of the liquid crystal display device is classified into a direct type and an edge type according to a method of disposing a lamp. The backlight unit used in the liquid crystal display device shown in FIG. 1 corresponds to an edge type. The direct type backlight unit is applied to a relatively large liquid crystal display device, whereas the edge type is applied to a relatively small liquid crystal display device.

Since the illustrated liquid crystal display has an edge type backlight unit, a lamp 21 for supplying light to at least one side of the liquid crystal panel 10 is disposed. The lower part of the liquid crystal panel 10 is provided with a light guide plate 24 for guiding the light from the lamp 21 toward the liquid crystal panel 10. The upper part of the light guide plate 24 diffuses light incident from the lamp 21. Optical sheets 23 such as diffusion plates for irradiating the liquid crystal panel 10 are laminated.

The lower portion of the lamp 21 is provided with a reflecting plate 22 formed of a material that reflects light. The reflecting plate 22 reflects the light emitted toward the lower side and the side of the liquid crystal panel 10 rather than the liquid crystal panel 10. It plays a role to let the exit in the direction of). The reflective plate 22 is stacked on top of the bottom cover 29, and the bottom cover 29 serves to protect and fix the backlight unit 20 from the bottom. The bottom cover has an inclined surface extending from the bottom surface and the bottom surface is fastened to the support main 27.

At this time, the top case 25 assembled on the upper portion of the liquid crystal panel 10 is manufactured in the form of a rectangular band having a flat portion and a side portion bent at a right angle. The top case 25 surrounds the edge of the liquid crystal panel 10 and the support main 27.

As described above, in order to drive the liquid crystal panel 10, a driving circuit printed circuit board (PCB) substrate 12 is connected through at least one side of the liquid crystal panel 10 through COF or TCP. In the COF or TCP, circuit wiring is formed on a thin and bendable plate-like material to apply an electrical signal of a driving circuit. Since the driving circuit portion is arranged in close contact with the back of the support main 27 or the cover bottom 16 in order to reduce the volume during the modularization process, the COF or TCP connecting the liquid crystal panel 10 and the PCB substrate 12 is the support main. It is arranged to bend along the outer periphery of (27).

However, in order to prevent the PCB substrate or the liquid crystal panel from flowing, the PCB substrate is fixed, and stress is applied to the COF or TCP portion attached to the PCB substrate. In this state, when the movement of the substrate is repeated due to the use of the liquid crystal display, or when external stress such as torsion or impact is applied, there is a problem in that the wiring part is not connected due to the attachment portion of the COF or TCP.

In order to solve the above problems, the present invention, by forming a dummy film in the COF electrically connecting the liquid crystal panel and the PCB substrate to increase the adhesion between the COF and the liquid crystal panel or the PCB substrate is applied to the external stress. The primary purpose is to prevent disconnection of wiring patterns. In addition, since the dummy film can be integrally formed by extending the insulating film, the defect of the liquid crystal display device can be reduced without any additional process or additional cost in the process. An object of the present invention is to provide a more reliable liquid crystal display device by the above method.

The present invention consists of a liquid crystal panel and a PCB substrate on which a driving circuit for driving the liquid crystal panel is mounted, and one end is attached to the liquid crystal panel and the other end is attached to and connected to the PCB substrate. In this case, the COF or TCP is characterized in that it comprises a flexible insulating film and a wiring pattern formed on the insulating film and a plurality of wirings and a dummy film formed on the outside of the wiring pattern.

The dummy film is not electrically connected to the liquid crystal panel or the PCB substrate, and is formed long in the direction in which the COF is attached to the dummy film and attached to the liquid crystal panel or the PCB substrate.

At this time, the dummy film includes extending by forming the insulating film.

The liquid crystal panel is formed by bonding a substrate on which a thin film transistor is formed and a substrate on which a color filter is formed. An optically anisotropic liquid crystal is filled between the two substrates, and when a voltage is applied, the liquid crystal layer produces an image by changing orientation. Since a voltage must be applied to drive the liquid crystal of the liquid crystal panel, it is common to mount a separate driving circuit on the PCB and connect the liquid crystal panel. Therefore, a circuit wiring for physically and electrically connecting the liquid crystal panel and the PCB board is required, which can be provided at this time is COF or TCP.

COF or TCP is formed on a flexible insulating film that can be bent to form wiring or circuits that can be electrically connected to other circuit wiring. Although COF and TCP have some differences, they are common in that circuit wiring is formed on them using flexible insulating films or tapes. COF and TCP can perform the same functions in liquid crystal display devices. . Therefore, in the present invention, both cases of COF and TCP may be provided and will be described below by representing COF.

2A and 2B are plan and cross-sectional views illustrating a connection state of a driving circuit PCB connected to a liquid crystal panel. As shown, at least one side of the liquid crystal panel 110 includes a COF 111 electrically connected to the liquid crystal panel 110. Each of the circuit wirings includes wirings for applying an electrical signal to the pixels of the liquid crystal panel. It is connected.

A wiring is formed on the COF 111 to supply an electrical signal of the driving circuit. Therefore, the COF can be used to electrically connect the liquid crystal panel and the PCB board on which the driving circuit for driving the liquid crystal panel is mounted, to supply an electrical signal along the wiring formed on the COF. The COF is attached to both ends of the liquid crystal panel and the PCB substrate. The wires formed on the COF are attached to the wires formed on the liquid crystal panel and the wires formed on the PCB, respectively, so that electrical signals from the PCB board are supplied to the liquid crystal panel through the wires of the COF. That is, in the liquid crystal display device, a signal is applied to the liquid crystal panel by the driving circuit through the COF so that an image is displayed on the liquid crystal panel. In order to connect the liquid crystal panel 110 and the PCB substrate 112 on which the driving circuit is mounted. One side of the COF 111 is attached to the liquid crystal panel 110 and the other side is attached to the PCB substrate 112. In this case, the portion where the COF 111 is attached to the liquid crystal panel 110 is a pad portion, not an area where an image appears.

If the COF or the PCB substrate is disposed on the same plane as the liquid crystal panel, the volume of the liquid crystal display device is increased. However, since the circuit board uses a flexible material (film or tape) of a bendable form, there is an advantage in that it can be variously bent. Therefore, using the bendable nature of the COF bend the COF in the U-shape along the outer periphery of the support main and then place the PCB substrate on the back of the liquid crystal panel.

Referring to the drawings, FIG. 3 is a cross-sectional view illustrating one side of an edge type liquid crystal display device in which each component is assembled, and FIG. 4 is a cross-sectional perspective view of a partially assembled liquid crystal display device.

As shown, the PCB substrate 112 for driving the liquid crystal panel 110 is disposed connected to the COF 111, and supports the COF 111 provided at the edge of the liquid crystal panel 110 to reduce volume. By bending along the outer periphery of the main 127, the PCB substrate 112 is positioned under the light guide plate 124.

However, when vibration, shock, or torsional stress is applied to the liquid crystal display device, a load is applied to the COF 111, and the COF 111 attached to the liquid crystal panel 110 or the PCB substrate 112. Problem occurs in the liquid crystal panel 110 or the PCB substrate 112. COF attached by external vibration, shock or torsion is weakening the adhesion force and eventually fall off the liquid crystal panel 110 or the PCB substrate 112, the wiring connected by the COF is broken. If such disconnection occurs, it leads to a defect of the liquid crystal display. In particular, the PCB substrate is fixed to the rear surface, but the liquid crystal panel is more frequently flown than the PCB substrate, so that disconnection occurs frequently at the edge 150 of the portion where the liquid crystal panel 110 and the COF 111 are connected. This disconnection occurs particularly well in the case of notebook computers, and the adhesion force is weakened by the torsional impact caused by the use, so that the COF is dropped and the metal wiring mounted on the COF 111 is easily broken. Therefore, a problem occurs that the circuit is defective.

Therefore, the present invention is characterized by forming a separate dummy film (dummy film) in the weak part of the COF in which disconnection frequently occurs in order to reduce the adhesion and weakening the adhesion of the main circuit wiring. As described above, the COF physically and electrically connects the liquid crystal panel and the PCB substrate. In fact, the dummy film is further formed by extending an insulating film portion in which no wires are electrically connected. The purpose is to reduce the disconnection of the main circuit wiring which is actually electrically connected by increasing the adhesion area and absorbing the impact from the dummy film even if the impact is applied from the outside.

The COF is a type of flexible printed circuit board, in which a circuit is formed of a conductive material on an insulating film or a tape (hereinafter, referred to as an insulating film). In the present invention, since a liquid crystal panel and a PCB substrate for driving the liquid crystal panel are connected, a plurality of wiring patterns are mounted on the insulating film.

Dummy film according to the present invention is characterized by extending the insulating film of the outer portion of the edge of the wiring pattern is not mounted, that is, the first wiring or the last wiring of the wiring pattern. Where the dummy film is formed corresponds to both ends of the portion attached to the liquid crystal panel or the PCB. This is because the stress applied to the COF is concentrated on the edge portion of the insulating film to reinforce the edge portion of the film to reinforce adhesion and prevent defects due to disconnection. The dummy film serves as a buffer under stress applied to the main wiring pattern, and further extends the outer side of the dummy film to attach to the dummy film, thereby increasing the adhesion area and increasing the adhesion to prevent the dummy film from falling off or disconnection.

The dummy film corresponds to a portion which is not electrically connected to the liquid crystal panel or the PCB. The dummy film does not need to be electrically connected because it is an additional configuration for preventing the attachment of the main wiring pattern and not for the electrical connection. As described above, the dummy film is formed in a portion where external stress is mainly concentrated, and since the dummy film is not electrically connected to the liquid crystal panel or the PCB, even if the attachment of the dummy film portion is reduced, there is no problem with the defect or defect of the liquid crystal display device. Not relevant

The dummy film may be formed outside of the wiring pattern, that is, where no wiring is formed. Therefore, it can form in either the outer side of a 1st wiring and a last wiring. That is, it can be formed on one side or both sides of the outer side of the wiring pattern. Alternatively, both sides of the wiring pattern as well as the upper and lower portions where the wiring is formed may be formed on all sides.

Therefore, the dummy film may be formed long in the direction in which the COF is attached. The COF is attached to electrically connect the liquid crystal panel or the PCB, and the attachment portion is formed perpendicular to the direction in which the circuit wiring is connected. The dummy film is formed long in the longitudinal direction of the attachment portion of the COF may be attached to the liquid crystal panel or the PCB substrate.

At this time, the dummy film is preferably formed by extending the insulating film. The dummy film may be separately formed and combined with the flexible insulating film and the wiring pattern. However, in the case of forming the dummy film by extending the insulating film, the same surface is connected and can be formed at one time, and there is no process of combining them. Therefore, it is preferable to form the insulating film with a long extension, and the material or other physical properties of the dummy film are the same as the insulating film.

Figure 5 shows the shape of the COF according to an embodiment of the present invention. This embodiment is a cross-sectional perspective view showing that a dummy film is formed in a portion 50 in which disconnection occurs frequently among the connection portions of the liquid crystal panel and the COF of FIG. 4B.

As shown, the COF is attached to the liquid crystal panel 210 and a wiring pattern (not shown) is formed on the insulating film 211. At this time, the COF is attached in a direction perpendicular to the direction in which the wiring pattern is formed. Therefore, the direction in which the COF is attached becomes a direction perpendicular to the direction in which the wiring pattern is formed, and is formed long along one side of the liquid crystal panel. The dummy film 202 is formed long in the direction in which the COF is attached, and can be formed on both sides of the outer side of the wiring pattern.

As shown in the above, especially, the portion where the liquid crystal panel and the COF are connected among the COF connection portions is a region in which a break occurs easily due to the stress or the flow of the liquid crystal panel in particular, and thus the dummy film is moved toward the connection region close to the liquid crystal panel. In addition, it can form widely. The connection area between the PCB and the COF is also susceptible to deformation due to the flow or torsional stress of the PCB, so that the dummy film can be formed even on the COF attached to the PCB.

Since the shape of the dummy film is to be attached to a large area in addition to the insulating film, it will be possible to form a variety of shapes for this function.

It is obvious that various changes and modifications can be made by those skilled in the art through the above description, and the scope of the present invention is not limited only to the above-listed embodiments. In particular, in the detailed description, the COF has been described as an example, but the present invention includes a flexible printed circuit board (TCP) if a circuit is formed on an insulating film. Therefore, the scope of the present invention should be defined by the scope of the claims rather than the details of the description.

The present invention is attached to a PCB substrate mounted with a liquid crystal panel and a driving circuit for driving the liquid crystal panel is formed by adding a dummy film to the COF electrically connecting the liquid crystal panel and the PCB substrate, thereby increasing the adhesion force of the COF to vibrate Even when stress such as a torsion or a torsion is applied, disconnection of the wiring pattern does not occur, thereby reducing the defect of the liquid crystal display device. In addition, since the dummy film can be formed integrally by extending the insulating film, the dummy film can be easily formed in the process, thereby improving the quality and efficiency of the liquid crystal display device.

Claims (6)

A liquid crystal panel; A PCB board on which a driving circuit for driving the liquid crystal panel is mounted; And One end is attached to the liquid crystal panel and the other end is composed of a COF or TCP attached to the PCB substrate, the COF or TCP, Flexible insulating film; A wiring pattern formed on the insulating film and formed of a plurality of wirings; And Liquid crystal display device comprising a dummy film formed on the outside of the wiring pattern. The method of claim 1, And the dummy film is not electrically connected to the liquid crystal panel or the PCB. The method of claim 1, The dummy film is formed long in the direction in which the COF is attached to the liquid crystal panel or the PCB substrate, characterized in that attached to the PCB. The method of claim 1, The dummy film is a liquid crystal display device, characterized in that formed by extending the insulating film. Flexible insulating film; A wiring pattern formed on the insulating film and formed of a plurality of wirings; And COF or TCP comprising a dummy film formed on the outside of the wiring pattern. The method of claim 5, The dummy film is COF or TCP, characterized in that formed by extending the insulating film.

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