JP2006017981A - Liquid crystal display device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To obtain a liquid crystal display device with high display quality, in which a desired ground electric potential is input in an IC for driving, even in the case an inner wire and a front frame are brought into contact with each other. <P>SOLUTION: The IC 7 for driving a display section 5a is mounted on the insulating substrate 4 of the liquid crystal display device, and at the same time, inner wires 9 to input a signal from an external circuit and a power supply to the IC 7 for driving are formed on the peripheral section 5b of the insulating substrate 4. An outermost wire to be nearest to the edge of the insulating substrate 4 out of the inner wires 9 is a ground wire 9a to input a ground power supply. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

The present invention is formed on an insulating substrate that constitutes a liquid crystal display panel, on a peripheral portion on an insulating substrate that inputs a signal and power from an external circuit to a driving IC that supplies a signal to a scanning line or a signal line. The present invention relates to a liquid crystal display device having a conductive film (hereinafter referred to as internal wiring).

  In a conventional liquid crystal display device, a plurality of semiconductor chips for driving the liquid crystal display device are connected face-down on a glass substrate, and input wiring is wired from the wiring substrate to the semiconductor chip (see, for example, Patent Document 1).

Japanese Patent Laid-Open No. 5-100240 (2nd page, FIG. 1)

  In a conventional liquid crystal display device, a scribe and break method is generally used as a dividing method in a dividing process of a panel manufacturing process for dividing a bonded glass substrate (hereinafter referred to as a cell) into a predetermined size. Occasionally, glass chipping occurred at the edge of the glass substrate. Thereby, the input wiring located in the peripheral part of a glass substrate is exposed to the surface of a display panel from the chip | tip part of a glass substrate, and contacts with the front frame of metal potential of a liquid crystal display device. For this reason, a desired signal or power supply from an external circuit is not input to the driving IC, and there is a problem that a display defect of the liquid crystal display device occurs.

The present invention has been made to solve the above-described problems. Even when the input wiring (internal wiring) and the front frame are in contact with each other, a desired ground potential can be input to the driving IC. A high quality liquid crystal display device is obtained.

  In the liquid crystal display device according to the present invention, the outermost peripheral wiring closest to the edge of the insulating substrate among the internal wirings for inputting the signal and power from the external circuit to the driving IC is provided on the peripheral portion of the insulating substrate. A ground wiring for inputting a ground power supply to the driving IC is used.

  According to the present invention, since the outermost peripheral wiring closest to the edge of the insulating substrate is a ground wiring for inputting the ground power to the driving IC, the internal wiring positioned at the peripheral edge of the glass substrate is not chipped of the glass substrate. A desired ground potential can be input to the driving IC even if it is exposed from the portion to the surface of the liquid crystal display panel and is in contact with a metal-made front frame of the display device.

Embodiment 1 FIG.
1 is an exploded perspective view showing a liquid crystal display device according to Embodiment 1 for carrying out the present invention, FIG. 2 is a plan view showing a part of a liquid crystal display panel mounted on the liquid crystal display device of FIG. 1, and FIG. [FIG. 3] It is a fragmentary sectional view which shows the manufacturing process of the part along the III-III line | wire of the liquid crystal display panel shown in FIG. 1, 2, and 3, the liquid crystal display device includes a backlight having a light guide plate 1 and a linear light source 2 disposed on at least one side of the light guide plate 1, and a backlight disposed on the front side of the backlight. The liquid crystal display panel 3 controls the light transmittance.

The liquid crystal display panel 3 includes two insulating substrates 4 facing each other, a spacer for holding the two insulating substrates 4 at equal intervals, a sealing material for bonding the two insulating substrates 4, and two insulating materials. A sealing material that seals after injecting liquid crystal between the substrate 4, an alignment film that imparts initial alignment to the liquid crystal, and a polarizing plate that has a function of transmitting only a specific polarization component with respect to light from the backlight. Composed. In the first embodiment, a glass substrate is used as the insulating substrate 4.

Of the two insulating substrates 4 facing each other, the electrode substrate 4a, which is one of the insulating substrates 4, is provided with a plurality of gate wirings and a plurality of source wirings. A thin film transistor (hereinafter referred to as TFT) which is a switching element is disposed. The pixel electrodes connected to the TFTs are arranged in a matrix to form the display unit 5a. The counter substrate 4b, which is the other insulating substrate, is provided with a counter electrode made of a transparent conductive film, a color filter layer for color display, a black matrix disposed between the pixels, and the like.

An electrode terminal 6 to which signals and power are supplied from an external circuit (not shown) is formed on the peripheral edge 5b located outside the display portion 5a on the electrode substrate 4a, and a driving IC 7 for driving the display portion 5a is provided with Chip On. It is mounted by the Glass (hereinafter referred to as COG) method. The driving IC 7 includes an input bump 7a and an output bump 7b, and the output bump 7b is connected to the driving IC output terminal 6b of the lead wiring 8 connected to the gate wiring or the source wiring.

The input bump 7a is connected to the driving IC input terminal 6a, and an internal wiring 9 connecting the electrode terminal 6 and the driving IC input terminal 6a is formed on the peripheral edge 5b of the electrode substrate 4a. As described above, the signal input to the driving IC 7 and the power supply are input from the external circuit via the electrode terminal 6 on the electrode substrate 4a.
In the pattern design of the internal wiring 9, the internal wiring 9 having a resistance value that does not cause an abnormality in the output of the driving IC 7 is laid out in a routable area determined by the size restriction of the liquid crystal display device.

The internal wiring 9 for inputting a signal and power to the driving IC 7 is classified into a signal system and a power system. The signal system is for a shift register clock, the start pulse, etc., the power system is a level shifter, and the output buffer power VGG. In total, about ten wires such as the ground power supply GND and the logic power supply VDD are drawn.

In particular, in the first embodiment, the outermost peripheral wiring closest to the edge of the electrode substrate 4a among the internal wirings 9 is used as the ground wiring 9a for inputting the ground power to the driving IC 7.

In the first embodiment, the shortest length L from the glass cutting line 17 to the position crossing the ground wiring 9a is longer than 0.7 mm in consideration of glass chipping caused by the empty cell cutting process described later. Thus, the outermost peripheral wiring of the internal wiring 9 is laid out. However, the present invention is not limited to this. You may lay out.

In addition, the liquid crystal display panel 3 and the backlight are held by the middle frame 12 that supports the liquid crystal display panel 3, the metal front frame 13, and the rear frame 14 on the backlight including the optical sheets 10 and the reflection sheet 11. The liquid crystal display device is configured.

The front frame 13 has a rectangular opening 13a substantially corresponding to the display portion 5a of the liquid crystal display panel 3, a rectangular ring-shaped horizontal portion 13b surrounding the opening 13a from four sides, and an outer periphery of the horizontal portion 13b. The vertical portion 13c extends downward from the whole.

The optical sheets 10 are diffusion sheets provided close to the light exit surface of the light guide plate 1, and the optical sheets 10 may be prism sheets or are composed of a plurality of sheets. Or nothing.

In addition, the reflection sheet 11 is provided in the vicinity of the surfaces other than the entrance surface and the exit surface of the light guide plate 1 and uses a diffuse reflection material having a reflectivity of 90% or more. .

Next, the manufacturing process of the electrode substrate 4a of the liquid crystal display panel 3 will be described.
First, a metal made of Cr, Al or the like serving as the first conductive film is deposited on the insulating substrate 4 such as a glass substrate by sputtering, and patterned by photolithography and etching to form the internal wiring 9 and the TFT gate electrode and A gate wiring (not shown) is formed (FIG. 3A).

Next, a gate insulating film 15 as a first insulating film, a non-doped amorphous semiconductor film, and an amorphous semiconductor film doped with an n-type impurity are successively deposited by CVD, and a non-doped amorphous semiconductor is formed by photolithography and etching. The film and the amorphous semiconductor film doped with n-type impurities are patterned to form a semiconductor layer and a contact layer (not shown).

Further, a metal such as Cr serving as the second conductive film is deposited by sputtering, and patterned by photolithography and etching to form TFT source and drain electrodes and source wiring (not shown).
At this time, only the gate insulating film 15 remains in the portion where the internal wiring 9 is formed (FIG. 3B).

Next, a passivation film 16 which is a second insulating film is deposited by CVD (FIG. 3C).
Next, contact holes (not shown) are formed in the gate insulating film 15 and the passivation film 16.

Finally, ITO (Indium Tin Oxide), which becomes a transparent conductive film so as to cover the contact hole, is deposited by sputtering, patterned by photolithography and etching, and the pixel electrode connected to the drain electrode through the contact hole (Not shown), a driving IC output terminal 6b connected to the lead-out wiring 8, and a driving IC input terminal 6a and an electrode terminal 6 connected to the internal wiring 9 are formed. The drive IC output terminal 6b, the drive IC input terminal 6a or the electrode terminal 6 is not formed of ITO, and the input bump 7a or the output bump 7b of the drive IC 7 or the output terminal of the external circuit is directly drawn out. The wiring 8 or the internal wiring 9 may be connected. The electrode substrate 4a is formed by the above process.

Next, in order to facilitate understanding of the present invention, a process of mounting the driving IC 7 on the electrode substrate 4a will be described before describing the dividing process of the panel manufacturing process.
First, ACF (Anisotropic Conductive Film) (not shown) is pasted on the driving IC input terminal 6a and the driving IC output terminal 6b formed on the peripheral edge 5b of the electrode substrate 4a.

Next, after a plurality of input bumps 7a and output bumps 7b made of Au formed on the back surface of the driving IC 7 and the driving IC input terminal 6a and the driving IC output terminal 6b are accurately aligned, a heating and pressing tool is used. Is used for thermocompression bonding.

The conditions at this time are, for example, a heating temperature of 170 to 200 ° C., a time of 10 to 20 seconds, and a pressure of 30 to 100 Pa. By thermocompression bonding, the input bumps 7a and the output bumps 7b are connected by the conductive particles of the ACF sandwiched between the input bumps 7a and the drive IC input terminals 6a, the output bumps 7b of the drive ICs 7 and the drive IC output terminals 6b. The driving IC input terminal 6a and the driving IC output terminal 6b become conductive.

In other words, the driving IC 7 is electrically connected to the driving IC input terminal 6a and the driving IC output terminal 6b of the electrode substrate 4a by thermocompression bonding via the ACF.
Note that the insulation of the ACF is maintained because an insulating epoxy resin exists around the conductive particles in the horizontal direction.

Subsequently, an ACF is also used for connection between an FPC (Flexible Printed Circuit) (not shown) for connection with an external input and an electrode terminal 6 for external input. The FPC is composed of a polyimide film having a thickness of about 30 to 70 μm, a copper foil having a thickness of 8 to 25 μm, and a polyimide solder resist.

Finally, an insulating coating material is applied to the electrode terminal 6 including the internal wiring 9 between the driving IC 7 and the FPC.
As the coating material, silicon resin, acrylic resin, fluororesin, urethane resin or the like is mainly used, and is applied using a dispenser. By applying the coating material to the electrode terminal 6, corrosion of the wiring can be prevented.

Next, an assembly process of the liquid crystal display device will be described. In the liquid crystal display device according to this embodiment, the liquid crystal display panel 3 on which the driving IC 7 is mounted on the electrode substrate 4a is mounted on the backlight serving as a flat light source, and the front frame 13 is fitted from the front side of the liquid crystal panel 3. It is assembled by inserting. The FPC connected to the electrode substrate 4a is connected to a circuit board (not shown).

Here, the order of the manufacturing process is before the step of mounting the driving IC 7 on the electrode substrate 4a, but an empty cell (cell containing no liquid crystal) in which the electrode substrate 4a and the counter substrate 4b are bonded together is used. The dividing process of the panel manufacturing process for dividing into a predetermined size will be described. The description of the manufacturing method of the counter substrate 4b, the assembly process of injecting the liquid crystal by overlapping the electrode substrate 4a and the counter substrate 4b, and the like will be omitted.

In the empty cell dividing step, the laminated glass substrate is divided into panel sizes, and a liquid crystal injection port is formed in the glass substrate.
The method of dividing a single plate and an empty cell is the same, but in the case of single plate division, the break bar is pushed up from the back side with the scribe line facing up, while in the case of empty cell division, the break is made with the scribe line behind. It is a method of hitting the bar from the front side, and the method of applying the force in the break process is different. Further, the flow of dividing the empty cell scribes the electrode substrate 4a, inverts the electrode substrate 4a, breaks the electrode substrate 4a, scribes the counter substrate 4b, inverts the counter substrate 4b, and breaks the counter substrate 4b.

When making a cut line (vertical crack) on the surface of the cell by a scriber (scribe machine), the cut line put on the cell surface generates a deviation amount (scribe perpendicular angle) from an ideal straight line. In addition, when a cell is divided by a break machine, the set dimension at the time of the break causes a deviation amount from the actual divided size. In the first embodiment, a range of 0.2 mm to the left and right with respect to the glass dividing line 17 that should be originally set is set as a region (width 2d) that may be panel-divided.

Moreover, when a cell is divided by a scriber, glass chipping may occur from the panel cross section. This glass chipped portion 18 has a chip of length l from the edge of the glass substrate which is a panel section. In the first embodiment, a description will be given assuming that a chip having a general length of 0.5 mm is generated as the length l of the glass chipped portion 18.

When a glass chip having a length l reaching the internal wiring 9 occurs in the electrode substrate 4a, the internal wiring 9 is exposed from the glass chipping portion 18 to the surface of the electrode substrate 4a. Here, in order to support the liquid crystal display panel 3 from the front side of the display panel 3 by the metal front frame 13 described above, the internal wiring 9 and the front frame come into contact with each other.

However, in the first embodiment, since the outermost peripheral wiring closest to the edge of the electrode substrate 4a among the internal wirings 9 is the ground wiring 9a, the driving is not affected by the ground potential of the front frame 13. A desired ground potential can be input to the IC 7 and a liquid crystal display device with high display quality can be obtained.

In the first embodiment, the shortest length L from the glass cutting line 17 to the position crossing the ground wiring 9a is longer than 0.7 mm. Even if the glass chipped portion 18 is cut into the inner side by a width of 0.2 mm and the length l of the glass chipped portion 18 is 0.5 mm, the ground that is the outermost peripheral wiring of the internal wiring 9 is formed by the glass chipped portion 18. There is no disconnection of the wiring 9a.

In the first embodiment, the ground wiring 9a is laid out so that the shortest length L from the glass dividing line 17 to the position crossing the ground wiring 9a is longer than 0.7 mm. What is necessary is just to set the shortest length L so that following Formula (1) may be satisfy | filled with the magnitude | size of the glass chip | tip by the cutting apparatus actually used.
L> d + 1 (1)

Further, if the width of the ground wiring 9a is w, the shortest length L that satisfies the following expression (2) may be set so that the glass chipped portion 18 does not reach the ground wiring 9a.
L> d + 1 + w (2)

Further, it is preferable to set the shortest length L for narrowing the frame by narrowing the width of the peripheral edge portion 5b located outside the display portion 5a as much as possible. For example, the shortest length L is set so as to satisfy the following expression (3), which is a position where the glass chipped portion 18 will reach the ground wiring 9a.
L = d + 1 + w (3)

Furthermore, in this Embodiment 1, although the glass chipping produced during the cutting process of a panel manufacturing process was demonstrated, there exists the same effect also about the glass chipping which may occur during conveyance of the electrode substrate 1a.

In the first embodiment, the internal wiring 9 is formed of a metal such as Cr as the first conductive film in the same process as the gate electrode and the gate wiring of the TFT. However, Cr or the like as the second conductive film is formed. The metal may be formed in the same process as the source and drain electrodes of TFT and the source wiring.

Embodiment 2. FIG.
FIG. 4 is a plan view showing a part of a liquid crystal display panel according to Embodiment 2 for carrying out the present invention, and FIG. 5 shows a part of another liquid crystal display panel according to Embodiment 2 for carrying out the present invention. FIG. 4 and 5, the same reference numerals as those in FIGS. 1, 2, and 3 indicate the same or corresponding parts, and the description thereof is omitted. Of the plurality of input bumps 7 a made of Au formed on the back surface of the driving IC 7, the ground bump 19 of the driving IC 7 connected to the ground wiring 9 a is at least one other input bump with respect to the electrode terminal 6. It is arranged closer to 7a. For example, as shown in FIG. 4, it is arranged between other adjacent input bumps 7a.
The ground wiring 9a is the outermost peripheral wiring that is closest to the edge of the electrode substrate 4a so as not to cross the internal wiring 9 that bypasses the other input bumps 7a and is connected to the other input bumps 7a under the driving IC 7. Arranged as.

The only difference from the first embodiment is that the ground bump 19 is disposed between the other adjacent input bumps 7a, and the ground wiring 9a bypasses the other input bumps 7a under the driving IC 7. Except for the operational effects of the ground bump 19 described later, the same operational effects as in the first embodiment are obtained.

In the second embodiment, the ground wiring 9a is connected to the driving IC 7 even when the driving IC 7 arranged between the other adjacent input bumps 7a is supplied according to the specifications of the driving IC manufacturer. By bypassing the other input bumps 7a below, the ground wiring 9a can be wired as the outermost peripheral wiring outside the driving IC 7.

In the second embodiment, the ground wiring 9a bypasses the other input bump 7a under the driving IC 7. However, as shown in FIG. 5, it is connected to the other input bump 7a through an insulating layer. The ground wiring 9a can also be wired as the outermost peripheral wiring by intersecting with the internal wiring 9.

In this case, for example, the internal wiring 9 connected to the other input bumps 7a is formed of the metal such as Cr serving as the first conductive film in the same process as the gate electrode and the gate wiring of the TFT, and the ground wiring 9a is formed as the second wiring. By forming the TFT with a metal such as Cr as the conductive film in the same process as the source and drain electrodes and the source wiring of the TFT, the internal wiring 9 and the ground wiring 9a connected to the other input bumps 7a through the gate insulating film 15 are formed. And can be crossed.

Embodiment 3 FIG.
FIG. 6 is a plan view showing a part of a liquid crystal display panel according to Embodiment 3 for carrying out the present invention. 6, the same reference numerals as those in FIGS. 1 to 5 denote the same or corresponding parts, and the description thereof is omitted. The liquid crystal display panel 3 according to Embodiment 3 is based on a TAB (Tape Automated Bonding) method. On the peripheral edge 5b, each driving IC 7 is provided by a TCP (Tape Carrier Package) 20 which is a connection wiring board mounted on a flexible board.

The internal wiring 9 for the driving IC 7 is drawn from the electrode terminal 6 along the peripheral edge and connected to the TCP 20 on which the driving IC 7 is mounted. Then, it is electrically connected to the driving IC 7 on the TCP 20. That is, the internal wiring 9 is formed on the peripheral edge portion 5b of the electrode substrate 4a, and inputs signals and power from an external circuit to the driving IC 7. Of the internal wiring 9, the outermost peripheral wiring closest to the edge of the electrode substrate 4 a is a ground wiring 9 a that inputs a ground power to the driving IC 7.

The only difference is that the driving ICs 7 are arranged on the peripheral edge 5b in a TCP (Tape Carrier Package) 20 mounted on a flexible substrate, and the same action as in the first embodiment is obtained. There is an effect.

It is a disassembled perspective view which shows the liquid crystal display device in Embodiment 1 for implementing this invention. It is a top view which shows a part of liquid crystal display panel mounted in the liquid crystal display device of FIG. It is a fragmentary sectional view which shows the manufacturing process of the part along the III-III line | wire of the liquid crystal display panel shown in FIG. It is a top view which shows a part of liquid crystal display panel in Embodiment 2 for implementing this invention. It is a top view which shows a part of other liquid crystal display panel in Embodiment 2 for implementing this invention. It is a top view which shows a part of liquid crystal display panel in Embodiment 3 for implementing this invention.

Explanation of symbols

4 Insulating substrate 4a Electrode substrate 5a Display portion 5b Peripheral portion 6 Electrode terminal 7 Driving IC
7a Input bump 9 Internal wiring 15 Gate insulating film 17 Panel cutting line 18 Glass notch 19 Ground bump 20 TCP

Claims (8)

A driving IC for driving the display unit is mounted on the insulating substrate on which the display unit is formed, and a signal and a power source from an external circuit are input to the driving IC at a peripheral portion of the insulating substrate. In the liquid crystal display device forming the internal wiring,
2. The liquid crystal display device according to claim 1, wherein, among the internal wirings, the outermost peripheral wiring closest to the edge of the insulating substrate is a ground wiring for inputting a ground power supply to the driving IC. A driving IC for driving the display unit is disposed on the insulating substrate on which the display unit is formed via a connection wiring board, and the driving IC is connected to the driving IC from an external circuit on the peripheral portion of the insulating substrate. In the liquid crystal display device forming the internal wiring for inputting the signal and power of
2. The liquid crystal display device according to claim 1, wherein, among the internal wirings, the outermost peripheral wiring closest to the edge of the insulating substrate is a ground wiring for inputting a ground power supply to the driving IC. The driving IC has a plurality of input bumps and output bumps,
Among the input bumps, a ground bump of the driving IC connected to the ground wiring is arranged closer to at least one other input bump with respect to an electrode terminal to which a signal or power is supplied from the external circuit. And
The liquid crystal display device according to claim 1, wherein the ground wiring does not intersect with an internal wiring that bypasses the other input bump and is connected to the other input bump under the driving IC. The driving IC has a plurality of input bumps and output bumps,
Among the input bumps, a ground bump of the driving IC connected to the ground wiring is arranged closer to at least one other input bump with respect to an electrode terminal to which a signal or power is supplied from the external circuit. And
The liquid crystal display device according to claim 1, wherein the ground wiring intersects with an internal wiring connected to the other input bump through an insulating layer. The insulating substrate is a glass substrate, L is the shortest length from a glass cutting line that should be originally to a position that crosses the ground wiring, and there is a possibility that the panel may be cut to the glass cutting line. When the width is d and the length of the glass chipped portion from the edge of the glass substrate that is a panel cross section is l,
L> d + 1
5. The liquid crystal display device according to claim 1, wherein: When the width of the ground wiring is w,
L> d + 1 + w
The liquid crystal display device according to claim 5, wherein: When the width of the ground wiring is w,
L = d + l + w
The liquid crystal display device according to claim 5, wherein: The insulating substrate is a glass substrate, and the shortest length L from the glass cutting line to the position crossing the ground wiring is longer than 0.7 mm. The liquid crystal display device according to any one of claims.

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