JP4435511B2 - Liquid crystal display - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a liquid crystal display device in which driver ICs (integrated circuits) are directly mounted on an array substrate.
[0002]
[Prior art]
In a known liquid crystal display device, an array substrate and a color filter substrate are opposed to each other, and a liquid crystal filled between the substrates operates to perform display. A substrate in which the array substrate and the color filter substrate face each other and liquid crystal is filled between the substrates is called a liquid crystal cell.
[0003]
In the array substrate, a plurality of signal lines and a plurality of gate lines are arranged vertically and horizontally, and switching elements called TFTs (thin film transistors) are provided at intersections thereof. The gate of the TFT is connected to the gate line, and the source is connected to the signal line. A pixel electrode is connected to the drain of the TFT. When a voltage is applied to the pixel electrode, an electric field is generated between the pixel electrode and the common electrode provided on the color filter substrate, and the liquid crystal operates. In other words, a gate voltage is applied to the gate line and the TFT is turned on. When a signal voltage is applied to the signal line at that time, a voltage is applied to the pixel electrode and the liquid crystal operates.
[0004]
In order to apply the gate voltage and the signal voltage, a driver IC is mounted on the liquid crystal cell, and a desired voltage is applied from the driver IC to the gate line and the signal line. The driver IC is mounted on the liquid crystal cell using a well-known mounting method called TAB (tape automated bonding) or COF (chip on flexible printed circuit) or a flexible printed circuit board called FPC (flexible printed circuit board). This is done using technology that incorporates a driver IC.
[0005]
When the array substrate is a horizontally long rectangle, the driver IC is mounted via the TAB / COF on the horizontal side of the array substrate and the TAB or FPC on the vertical side, so a large number of TAB / COFs are used. Yes. Thus, there is no need to use TAB / COF, and in order to reduce the cost for these, there is a technique of directly wiring bus wiring instead of TAB / COF or FPC to the array substrate. In the array substrate 52 of the liquid crystal cell 51 shown in FIG. 8, bus wiring is drawn to the driver mounting portion 58 which is a portion not facing the color filter substrate 54. Then, the driver IC 56 is mounted directly on the array substrate 52 by a mounting method called COG (chip on glass).
[0006]
In order to supply power to the driver ICs 56 on the array substrate 52, as shown in FIG. 9, a plurality of driver ICs 56 may be connected by a bus wiring 60 to supply power to all the driver ICs 56 from one place. In this case, the through wiring 61 is provided in the chip 56 and below the chip 56 for wiring. This is effective when the driver mounting portion 58 is narrow and the power supply bus wiring 60 cannot be drawn for each driver IC 56. Since the area of the driver mounting portion 58 is not increased, the liquid crystal cell 51 does not increase. For example, the width of the driver mounting portion 58 is about 2 mm, and the width of the wirings 60 and 61 is about 200 μm.
[0007]
With the increase in size and definition of the liquid crystal display device 50, the total amount of current flowing through the entire liquid crystal display device 50 is increasing. For example, an XGA (extended graphics array) liquid crystal display device 50 has 3072 signal lines, and even if a current of 1 mA flows per line, the total current amount is about 3A. Therefore, since the value of the current passed through the wirings 60 and 61 also increases, the cross-sectional area of the wirings 60 and 61 needs to be increased. Since the thickness of the wirings 60 and 61 that can be formed in the manufacturing process of the array substrate 52 is very thin, about 2000 to 3000 mm, it is necessary to increase the width of the wirings 60 and 61 accordingly. However, the narrowing of the frame of the liquid crystal display device 50 has progressed, and this becomes a problem as the width of the driver mounting portion 58 cannot be increased. Moreover, in order to reduce the number of the wirings 60 and 61, as shown in FIG. 9, the wirings 60 and 61 are provided in series. As a result, since a large current flows through the wirings 60 and 61, a large burden is applied to the joint between the driver IC 56 and the wirings 60 and 61, and the wirings 60 and 61 may be melted.
[0008]
[Problems to be solved by the invention]
SUMMARY OF THE INVENTION An object of the present invention is to provide a liquid crystal display device corresponding to a narrow frame of a liquid crystal cell and reducing a burden on a connection portion between a driver IC and a wiring due to a large current flowing in the wiring.
[0009]
[Means for Solving the Problems]
The gist of the liquid crystal display device of the present invention is that an array substrate in which a plurality of electrode lines are formed vertically and horizontally, and an electrode line at a peripheral edge of the array substrate are exposed, and the color filter is opposed to the array substrate with a certain interval. A substrate; a non-display area of the array substrate; and an insulating layer formed at a position facing the color filter substrate and covering the electrode lines; a power supply wiring formed on the insulating layer; and the array substrate And a driver IC connected to the electrode line and a lead-out line connecting the power supply line and the driver IC. Since the insulating layer is formed in the non-display area and the power supply wiring is formed thereon, the wiring width of the power supply wiring is wider than that of the conventional power supply wiring. Therefore, when a high current is passed through the driver IC, the power supply wiring is less likely to melt.
[0010]
The insulating layer is a resin (polymer). The insulating layer composed of this resin is formed by a method of applying and curing a liquid resin, or a method of adhering a film-like resin by an adhesive or thermocompression bonding, and can easily form a resin layer. .
[0011]
There are a plurality of power supply lines and lead lines, and the power supply lines and the lead lines cross each other through an insulating film. The number of power supply lines is determined by the number of terminals of the driver IC. However, when there are a plurality of power supply lines, the number of lead lines is also plural. Therefore, three-dimensional crossing is performed via the insulating film.
[0012]
There are a plurality of the power supply lines and lead lines, and the power supply lines are divided into two at the location where the power supply lines and the lead lines intersect in a non-contact manner, and the power supply lines are divided into two under the insulating layer. Provide a bypass line to connect the wiring. In addition to providing an insulating film on the power supply wiring, it is also possible to realize a three-dimensional crossover between the power supply wiring and the lead-out wiring using an insulating layer.
[0013]
DETAILED DESCRIPTION OF THE INVENTION
An embodiment of a liquid crystal display device according to the present invention will be described with reference to the drawings. In the liquid crystal display device 10 of the present invention, an insulating layer 22 is provided in the non-display area 20 of the array substrate 12 of the liquid crystal cell 11 shown in FIGS. 1A and 1B, and a power supply wiring 24 is provided on the insulating layer 22. Power is supplied to the driver IC 16 by the lead wiring 26 formed and branched from the power supply wiring 24. In FIG. 1B, gate lines and the like on the array substrate 12 are omitted. As shown in FIG. 2, a desired signal voltage is applied to the gate line 28 or the like connected to the terminal (bump) 30b of the driver IC 16, and the liquid crystal display device 10 operates.
[0014]
More specifically, as shown in FIGS. 1A and 1B and FIGS. 3A and 3B, the liquid crystal display device 10 is opposed to the array substrate 12 with a certain distance from the array substrate 12. In the color filter substrate 14 and the array substrate 12, the insulating layer 22 facing the color filter substrate 14 and formed in the non-display area 20, the power supply wiring 24 formed on the insulating layer 22, and the array substrate 12 includes a driver IC 16 disposed in the driver mounting portion 18 that is a region where the color filter substrate 14 does not face, and a lead-out wiring 26 that connects the power supply wiring 24 and the driver IC 16.
[0015]
In FIGS. 3A and 3B, the number of the power supply lines 24 is different because it differs depending on the product of the liquid crystal display device 10, and the number of the power supply lines 24 is arbitrary. In FIG. 3B, a transfer 33 is provided, and this transfer 33 supplies a common potential to the color filter substrate 14.
[0016]
The array substrate 12 has electrode lines such as signal lines and gate lines formed vertically and horizontally on the surface of a glass substrate, and these electrode lines are drawn out to the peripheral edge. A TFT is provided at the intersection of the signal line and the gate line. A gate line is connected to the gate of the TFT, and a signal line is connected to the source of the TFT. A pixel electrode is connected to the drain of the TFT. Liquid crystal is sealed between the array substrate 12 and the color filter substrate 14, and the liquid crystal operates when a voltage is applied to the pixel electrode. The liquid crystal display device 10 performs display by operating the liquid crystal. The display area 19 is an area in which liquid crystal is sealed, and the non-display area 20 is an area that is hidden by a casing that supports the liquid crystal cell 11 when configured as the liquid crystal display device 10. In general, the driver mounting portion 18 is also a non-display area, but in this specification, the peripheral portion is referred to as a non-display area where the array substrate 12 and the color filter substrate 14 face each other. The liquid crystal is prevented from leaking from the liquid crystal cell 11 by the seal 32.
[0017]
As shown in FIG. 2, a desired voltage is applied from the driver IC 16 to the gate line 28 and the signal line. The array substrate 12 and the color filter substrate 14 are different in size. When the array substrate 12 and the color filter substrate 14 face each other, part of the gate lines 28 and signal lines drawn to the peripheral edge of the array substrate 12 are exposed. The driver IC 16 is mounted on a driver mounting portion 18 that is an area on the array substrate 12 where the color filter substrate 14 does not face. That is, the driver IC 16 is directly mounted on the array substrate 12.
[0018]
The insulating layer 22 is stacked on the non-display area 20 of the array substrate 12 where the array substrate 12 and the color filter substrate 14 face each other and the liquid crystal is not sealed. The insulating layer 22 is formed of a photosensitive or non-photosensitive organic resin insulating film. The insulating layer 22 is formed by a method in which a liquid resin (polymer) is applied and cured, or a method in which a film-like resin is bonded by an adhesive or thermocompression bonding. The insulating layer 22 covers the gate line 28 and the signal line as an insulator in the non-display area 20 together with a passivation layer described later. As an example, there is a method in which a photosensitive acrylic resin is used for the insulating layer 22 and, after coating, a predetermined contact hole is provided by exposure / development and then baked and cured.
[0019]
By providing the resin for forming the insulating layer 22 also in the display area 19 of the array substrate 12, the signal lines and the pixel electrodes can be overlapped, and the aperture ratio of the liquid crystal display device 10 can be increased. . The insulating layer 22 is stacked on a passivation layer (not shown) that protects the gate lines 28 and the signal lines formed on the glass substrate constituting the array substrate 12. The passivation layer is made of an insulator such as an oxide film or a nitride film.
[0020]
The power supply to the driver IC 16 is performed by forming a power supply wiring 24 on the insulating layer 22 and forming a lead wiring 26 from the power supply wiring 24 to the driver IC 16. A terminal (bump) 30 a of the driver IC 16 is connected to one end of the lead wiring 26, and the other end is connected to the power supply wiring 24.
[0021]
The power supply wiring 24 and the lead-out wiring 26 are provided by forming a material such as silver, copper, or gold on the insulating layer 22 using a known method such as screen printing, vacuum deposition, or plating.
[0022]
In general, the driver IC 16 has a plurality of terminals 30a. There are also a plurality of power supply lines 24 and lead lines 26. Therefore, as shown in FIG. 1B and FIG. 4, the power supply wiring 24 and the lead-out wiring 26 are three-dimensionally crossed via the insulating film 34. As shown in FIG. 5, the insulating film 34 is formed on the power supply wiring 24 where the three-dimensional crossover is performed.
[0023]
In the present invention, the array substrate 12 and the color filter substrate 14 that have not been conventionally used are opposed to each other, and the power supply wiring 24 is formed in the non-display region 20. Accordingly, it is possible to form the power supply wiring 24 having a width wider than that of the conventional one, the resistance of the power supply wiring 24 is reduced, and a high current can flow through the power supply wiring 24 and the lead-out wiring 26. As an example, the width of the power supply wiring 24 is about 300 μm, the distance between the power supply wirings 24 is about 100 μm, the width of the lead-out wiring 26 is about 50 μm, and the distance between the lead-out wirings 26 is about 50 μm. In this case, even if a current of about 3 A is applied, the power supply wiring 24 and the lead-out wiring 26 can withstand without melting.
[0024]
As mentioned above, although embodiment of this invention was described, this invention is not limited to said embodiment. As shown in FIGS. 4 and 5, the insulating film 34 is provided and the lead-out wiring 26 is formed thereon. However, the power supply wiring 24 and the lead-out wiring 26 may be three-dimensionally crossed by other methods. For example, as shown in FIG. 6, the power supply wiring 24 and the lead-out wiring 26 are formed on the same insulating layer 22. The power supply wiring 24 is divided into two at the position where the three-dimensional crossover is performed, and the divided power supply wiring 24 is connected by a bypass line 40. The bypass line 40 is formed on a passivation layer that protects the gate line 28 and the like. In other words, the bypass line 40 is formed on the lower surface of the insulating layer 22. The power supply wiring 24 and the bypass line 40 are connected by providing a contact hole 42 in the insulating layer 22 and embedding a conductor in the contact hole 42.
[0025]
As shown in FIG. 7, a passivation layer 38 may be formed to protect the power supply wiring 24 and the lead-out wiring 26. The passivation layer 38 is formed of an oxide film or a nitride film. The passivation layer 38 is formed on the array substrate 12 other than the area where the terminal 30 of the driver IC 16 is connected. The passivation layer 38 is formed by forming an organic material such as polyimide by a known screen printing, dispensing, or photo process, or patterning a silicon nitride film formed by sputtering or CVD (chemical vapor deposition) by a photo etching process. Alternatively, it is formed by a method such as mask sputtering.
[0026]
In FIGS. 3A and 3B, the power supply wiring 24 is provided on the insulating layer 22 made of a polymer. However, power is supplied on a passivation layer (not shown) that is an insulating layer for protecting the gate line 28. The wiring 24 may be formed. As shown in FIGS. 4 and 5, an insulating film 34 is provided at a location where the power supply wiring 24 and the lead-out wiring 26 cross each other.
[0027]
As shown in FIG. 1, the array substrate 12 is rectangular, and driver mounting portions 18 are provided on two sides thereof. In general, the power supply wiring 24 is formed in the non-display area 20 adjacent to the driver mounting portion 18 in the non-display area 20, but power is also supplied to the non-display area 20 not adjacent to the driver mounting portion 18 as necessary. The wiring 24 may be formed.
[0028]
Although the embodiment of the present invention has been described above, the present invention is not limited to the above embodiment. In addition, the present invention can be implemented in a mode in which various improvements, modifications, and changes are made based on the knowledge of those skilled in the art without departing from the spirit of the present invention.
[0029]
【The invention's effect】
According to the present invention, a power supply wiring is provided at a location where wiring has not been conventionally performed, whereby a wiring having a wide wiring width and low resistance can be performed. When supplying power to the driver IC, since the width of the power supply wiring is wide, the power supply wiring is less likely to be blown by a high current. In addition, since wiring is performed in a region where power supply wiring has not been formed in the past, the space of the array substrate can be effectively used, and it is possible to cope with the so-called framed portion of the liquid crystal display device.
[Brief description of the drawings]
1A and 1B are views showing a liquid crystal display device of the present invention, in which FIG. 1A is a top view and FIG. 1B is an enlarged view of a main part of an array substrate.
FIG. 2 is a diagram illustrating connection of a power supply wiring and a gate line to a driver IC.
3 is a cross-sectional view taken along the line XX ′ of FIG. 1B, FIG. 3A is a cross-sectional view of eight power supply wirings, and FIG. 3B is a cross-sectional view at a position where a transfer is provided; is there.
4 is a cross-sectional view taken along the line YY ′ of FIG. 1B showing the position where the lead-out wiring is provided on the insulating film on the power supply wiring.
FIG. 5 is a diagram showing an insulating film provided on a power supply wiring.
FIG. 6 is a diagram in which a power supply wiring and a lead-out wiring are three-dimensionally crossed by providing a bypass line.
FIG. 7 is a diagram in which a passivation layer is provided on a power supply wiring.
FIG. 8 is a diagram of a liquid crystal display device in which a driver IC is mounted on a driver mounting portion.
FIG. 9 is a diagram in which driver ICs are connected in series.
[Explanation of symbols]
10, 50: Liquid crystal display device 11, 51: Liquid crystal cell 12, 52: Array substrate 14, 54: Color filter substrate 16, 56: Driver IC
18, 58: Driver mounting portion 19: Display area 20: Non-display area 22: Insulating layer (polymer)
24: Power supply wiring 26: Lead-out wiring 28: Gate lines 30a, 30b: Terminal (bump)
32: Seal 33: Transfer 34: Insulating film 36: Protective film 38: Passivation layer 40: Bypass line 42: Contact hole 60: Bus wiring 61: Through wiring

Claims (4)

An array substrate having a plurality of electrode lines formed vertically and horizontally;
So as to expose the electrode line of the periphery of the array substrate and a color filter substrate facing with a predetermined gap between the array substrate,
An insulating layer that is formed in a non-display area of the array substrate and is opposed to the color filter substrate and covers the electrode lines;
A power supply wiring formed on the insulating layer;
A driver IC arranged at a position not facing the color filter substrate of the array substrate and connected to the electrode line;
A lead-out line connecting the power supply line and the driver IC;
Including a liquid crystal display device.   The liquid crystal display device according to claim 1, wherein the insulating layer is a resin insulating film.   3. The liquid crystal display device according to claim 1, wherein there are a plurality of power supply lines and lead lines, an insulating film is provided on the power supply lines, and the power supply lines and the lead lines cross each other through the insulating film. .   There are a plurality of power supply lines and lead lines, and the power supply lines are divided into two parts where the power supply lines and the lead lines intersect in a non-contact manner, and the power supply lines are divided into two parts under the insulating layer. The liquid crystal display device according to claim 1, wherein a bypass line for connecting the wiring is provided.

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