JP5004908B2 - Liquid crystal display - Google Patents

Description

  The present invention relates to a display device, and more particularly to a structure of a liquid crystal display device that can be repaired when a defect such as wiring occurs in a process.

  Since the liquid crystal display device is flat and lightweight, the application is expanding in various fields such as a large display device such as a TV, a mobile phone, and a DSC (Digital Still Camera).

  In a liquid crystal display device, there are a TFT substrate in which pixel electrodes and thin film transistors (TFTs) are formed in a matrix, and a counter substrate in which color filters are formed at locations corresponding to the pixel electrodes of the TFT substrate, facing the TFT substrate. The liquid crystal is sandwiched between the TFT substrate and the counter substrate. An image is formed by controlling the light transmittance of the liquid crystal molecules for each pixel.

  Each pixel is supplied with a video signal from a video signal line via a thin film transistor (TFT). The TFT is turned on and off by supplying a scanning signal from the scanning line. When a TFT becomes defective, the corresponding pixel also becomes defective, resulting in a screen defect. If the number of screen defects exceeds a certain number, the liquid crystal display panel itself becomes defective.

  Therefore, even if a TFT becomes defective, if there is a means for compensating for this in some way, the manufacturing yield of the liquid crystal display panel can be improved, and the cost of the liquid crystal display device can be reduced. “Patent Document 1” describes a configuration in which a spare TFT is arranged for each pixel in addition to the main TFT, and the spare transistor is used when the main TFT becomes defective.

  In “Patent Document 1”, when a spare transistor is used, first, the main TFT is separated from the pixel electrode. At the same time, a configuration is described in which a pixel electrode and a TFT and a video signal line and a TFT are connected using a correction line. In “Patent Document 1”, the correction line is formed by laser CVD.

  Further, in “Patent Document 2”, when a scanning line or a video signal line is disconnected, a conductive metal layer formed over a part of a pixel electrode is irradiated with a laser, and the wiring is formed by laser welding. A configuration for repairing disconnection of a scanning line or a video signal line is described.

JP 2007-292878 A JP 09-1113930 A

  In the technique described in “Patent Document 1”, it is possible to separate a normal TFT and connect a spare TFT to a video signal line and a pixel electrode for each pixel. However, the technique described in “Patent Document 1”. Then, it is necessary to form a correction line by laser CVD. Laser CVD has a slow film formation speed, and it takes time to form a correction line. Further, the correction line by laser CVD has high resistance, and the response to the scanning signal or the video signal becomes slow.

  The technique described in “Patent Document 2” can avoid that all the pixels on the video signal line where the disconnection has occurred or all the pixels on the scanning line where the disconnection has occurred become defective. However, since the video signal line or the scanning line is repaired by the conductive metal layer formed on the pixel electrode, the corresponding pixel electrode becomes defective. In addition, a process for forming a conductive metal layer is added.

  The present invention overcomes the above-described problems, and even if a TFT becomes defective in each pixel, it is not necessary to form an additional pattern for repair when the corresponding pixel is repaired by using a spare TFT. In addition, there is provided a means that does not take a long time for the repair process and can suppress an increase in resistance after the repair.

  The present invention overcomes the above problems, and a main TFT that is normally used and a spare TFT that is used when the main TFT becomes defective are arranged. When the main TFT becomes defective, the main TFT is disconnected from the video signal line and the pixel electrode, and the spare TFT is connected to the video signal line and the pixel electrode.

  The present invention makes it possible to disconnect the main TFT and connect the spare TFT using laser cutting and laser welding by adopting a new configuration of the configuration and peripheral configuration of the main TFT and the configuration and peripheral configuration of the spare TFT. To do.

  According to the present invention, even when the TFT in the pixel portion becomes defective, it is possible to prevent the pixel from becoming defective by forming the spare TFT in advance. Yield can be improved.

  Further, according to the present invention, when the main TFT becomes defective, the main TFT is insulated from the video signal line and the pixel electrode by using laser cutting, and the spare TFT is formed in advance using laser welding. Since it is possible to operate by connecting to the wiring, the process of operating the spare TFT can be performed easily and in a short time.

  The present invention provides an effective configuration for operating a pixel as usual by using a spare TFT when a TFT formed in the pixel becomes defective. The contents of the present invention will be described below in detail according to examples.

  FIG. 1 is a sectional view of the present embodiment, and FIG. 2 is a plan view of the present embodiment. FIG. 1 is a cross-sectional view of an IPS (In Plane Switching) type liquid crystal display device. In the present invention, a main TFT and a spare TFT are arranged in each pixel, but the basic structure is the same. In this embodiment, the IPS system will be described as an example. However, the present invention can be similarly applied to other driving systems such as TN (Twisted Nematic) and VA (Vertical Alignment).

  FIG. 1 is a cross-sectional view in the vicinity of a TFT of an IPS to which the present invention is applied, and corresponds to a cross-sectional view along AA in FIG. In FIG. 1, a scanning line 300 is formed on a TFT substrate 100 made of glass. The scanning line 300 is made of an Al (aluminum) alloy. A first scanning branch line and a second scanning branch line are formed on the scanning line via a slit. The first scanning branch line and the second scanning branch line are used when the spare TFT is operated as will be described later.

  A gate insulating film 102 is formed of SiN so as to cover the scanning line 300, the first scanning branch line 301, and the second scanning branch line 302. A semiconductor layer 103 is formed of a-Si on the gate insulating film 102 at a position facing the scanning line 300. a-Si is formed by plasma CVD. Although a-Si forms a channel portion of the TFT, an n + Si layer 1031 is formed on the a-Si across the channel portion. This is to make ohmic contact with the source electrode 104 and the drain electrode 105. A source electrode 104 and a drain electrode 105 are formed on the n + Si layer 1031.

  The drain electrode 105 is connected to the video signal line 200, and the source electrode 104 is connected to the pixel electrode 110 through a through hole (not shown). The source electrode 104 and the drain electrode 105 are simultaneously formed in the same layer. In this embodiment, the source electrode 104 or the drain electrode 105 is made of an Al alloy.

  An inorganic passivation film 106 is formed of SiN so as to cover the TFT. The inorganic passivation film 106 protects the TFT, particularly the channel portion, from impurities. A pixel electrode 110 (not shown) is formed on the inorganic passivation film 106. The pixel electrode 110 is a comb-like electrode and is made of ITO, which is a transparent conductive film. When a video signal is applied to the pixel electrode 110, lines of electric force are generated between the pixel electrode 110, the liquid crystal molecules are rotated, and the amount of light transmitted through the liquid crystal layer is controlled. An alignment film 120 is formed on the pixel electrode 110.

  FIG. 2 is a plan view showing a first embodiment of the present invention. In FIG. 2, the video signal line 200 extends in the vertical direction, and the scanning line 300 extends in the horizontal direction. In the display area, the scanning lines 300 are arranged at equal pitches in the vertical direction, and the video signal lines 200 are arranged at equal pitches in the horizontal direction. A scanning line hole 310 is present at the intersection of the scanning line 300 and the video signal line 200. This is because the capacity of the video signal line 200 and the scanning line 300 is reduced. The pixel electrode 110 exists in a region surrounded by the scanning line 300 and the video signal line 200.

  A main TFT 10 and a spare TFT 20 are formed on the scanning line 300. Therefore, the scanning line 300 also serves as a gate electrode for the main TFT 10 and the spare TFT 20. In a normal state, the main TFT 10 has a role as a switching TFT, and the spare TFT 20 is not connected to the video signal line 200 or the pixel electrode 110 and is in a floating state.

  In FIG. 2, the drain electrode 105 of the main TFT 10 is branched from the video signal line 200 and extends on the semiconductor layer 103, and has a W shape. Two source electrodes 104 are arranged at a position surrounded by the drain electrode 105. Therefore, four channel portions are formed in the main TFT 10.

  In FIG. 2, the source electrode 104 is connected to the pixel electrode 110 through the through hole 111. A common electrode 108 is formed below the pixel electrode 110 via an interlayer insulating film and a gate insulating film 102 (not shown).

  In FIG. 2, a spare TFT 20 that is not normally used is formed on the scanning line 300. A semiconductor layer 103 is formed on the scanning line 300, a U-type drain electrode 105 is formed on the semiconductor layer 103, and a source electrode 104 is disposed inside the drain electrode 105. A first scanning branch line 301 branched from the scanning line 300 is disposed below the source electrode 104 of the spare TFT 20. Further, a second scanning branch line 302 branched from the scanning line 300 is disposed below the drain electrode 105 of the spare TFT 20.

  The source electrode 104 and the drain electrode 105 of the spare TFT 20 are normally not connected to the pixel electrode 110 or the video signal line 200, and the spare TFT 20 is in a floating state. When the main TFT 10 becomes defective for some reason, the main TFT 10 is disconnected from the pixel electrode 110 or the video signal line 200 to be in a floating state, and the spare TFT 20 is connected to the pixel electrode 110 and the video signal line 200 instead. Specifically, it is as follows.

  First, a laser is applied to the position of the cutting line indicated by the dotted line LS in FIG. 2 to cut this portion. Cutting by the laser is a connection portion between the drain electrode 105 of the main TFT 10 and the video signal line 200 and a connection portion between the source electrode 104 and the pixel electrode 110. As a result, the main TFT 10 is separated from the pixel electrode 110 and the video signal line 200, and the main TFT 10 is brought into a floating state.

  The other part of the cutting line by the laser is the base part of the first scanning branch line 301 and the second scanning branch line 302. As a result, the first scanning branch line 301 and the second scanning branch line 302 are separated from the scanning line 300.

  Thereafter, at the position of LW, the source electrode 104 of the spare TFT 20 and the first scanning branch line 301, and the first scanning branch line 301 and the pixel electrode 110 are connected by laser welding. The pixel electrode 110 and the first scanning branch line 301 are connected to a connection electrode 1051 formed in the same layer as the source electrode 104 by laser welding, and the connection electrode 1051 is connected to the pixel electrode 110 through the through hole 111. In this way, the source electrode 104 of the spare TFT 20 and the pixel electrode 110 are connected via the first scanning branch line 301.

  Similarly, the drain electrode 105 of the spare TFT 20 and the second scanning branch line 302, and the second scanning branch line 302 and the video signal line 200 are connected by laser welding. Then, the drain electrode 105 of the spare TFT 20 and the video signal line 200 are connected via the second scanning branch line 302. In this way, the spare TFT 20 functions as a switching TFT for the pixel electrode 110.

  As described above, the feature of the present invention is that when the spare TFT 20 is operated, the image signal line 200 or the pixel electrode 110 is connected via the first scanning branch line 301 or the second scanning branch line 302 branched from the scanning line 300. Since the connection is made, there is no need to provide a process for forming a conductive film for connection. Also, laser welding is very fast and requires very little time for repair.

  The general process of laser welding is as shown in FIG. In FIG. 3A, the gate insulating film 102 is formed on the first scanning branch line 301 branched from the scanning line 300, and the drain electrode 105 of the spare TFT 20 is formed on the gate insulating film 102. . In a normal state, the first scanning branch line 301 and the drain electrode 105 of the spare TFT 20 are insulated by the gate insulating film 102. The source electrode 104 and the first scanning branch line 301 of the spare TFT 20 are made of an Al alloy.

  When the main TFT 10 becomes defective and it is desired to use the spare TFT 20, the laser LA is partially irradiated as shown in FIG. This laser power is selected such that the gate insulating film 102 is evaporated but the source electrode 104 of the spare TFT 20 is fused. Then, as shown in FIG. 3B, the source electrode 104 of the spare TFT 20 is melted by the laser and welded to the hole portion of the gate insulating film 102 evaporated by the laser. Therefore, the source electrode 104 of the spare TFT 20 and the first scanning branch line 301 are brought into conduction. Since the source electrode 104 is made of an Al alloy, such laser welding can be easily performed.

  The connection between the connection electrode 1051 formed from the Al electrode and extending from the pixel electrode 110 in FIG. 2 in the same layer as that of the source electrode 104 and the first scanning branch line 301 is also performed in the same manner as in FIG. On the other hand, since the first scanning branch line 301 is separated from the scanning line 300 by the cutting line, it is not affected by the scanning signal.

  The connection between the drain electrode 105 of the spare TFT 20 of FIG. 2 and the video signal line 200 is the same. That is, the drain electrode 105 of the spare TFT 20 and the second scanning branch line 302 are connected by a mechanism as shown in FIG. 3, and the connection between the second scanning branch line 302 and the video signal line 200 is also a mechanism as shown in FIG. Is done by. Since the drain electrode is also made of an Al alloy, laser welding can be easily performed. Further, since the second scanning branch line 302 is separated from the scanning line 300 by laser cutting, the second scanning branch line 302 is not affected by the scanning signal.

  As described above, in this embodiment, the spare TFT 20 is connected to the video signal line 200 and the pixel electrode 110 via the first scanning branch line 301 or the second scanning branch line 302 by using laser welding. The process takes a short time and the connection resistance can be kept small. Further, since it can be performed for each pixel, it is very effective for repairing a pixel defect.

  In the first embodiment, the video signal line 200 and the second scanning branch line 302 intersect even when the main TFT 10 is operated. Therefore, the capacity of the video signal line 200 and the second scanning branch line 302 increases. As the capacity of this portion increases, the switching speed decreases. The second embodiment of the present invention shown in FIG. 4 enables the operation of the spare TFT 20 while suppressing the capacitance between the video signal line 200 and the scanning line 300.

  4 corresponds to FIG. 8, and the CC section of FIG. 4 corresponds to FIG. In FIG. 4, the video signal line 200 extends in the vertical direction. A scanning line 300 extends in the horizontal direction so as to intersect with the video signal. In the display area, the scanning lines 300 are arranged at equal pitches in the vertical direction, and the video signal lines 200 are arranged at equal pitches in the horizontal direction. A pixel electrode exists in a region surrounded by the scanning line 300 and the video signal line 200. The main TFT 10 and the spare TFT 20 are installed on the scanning line 300. In the normal state, the main TFT 10 is connected to the video signal line 200. In FIG. 4, the pixel electrode 110 and the connection between the pixel electrode 110 and the main TFT 10 are omitted.

  When a defect occurs in the main TFT 10, the connection between the main TFT 10 and the video signal line 200 and the connection between the main TFT 10 and the pixel electrode 110 are disconnected by laser irradiation. Instead, it is necessary to connect the spare TFT 20 to the video signal line 200. In this embodiment, the spare TFT 20 and the video signal line 200 are connected using the drain electrode 105 and the common wiring 1081 of the spare TFT 20.

  Normally, as shown in FIG. 8, the drain electrode 105 and the common wiring 1081 are insulated by a gate insulating film 102. When it is desired to operate the spare TFT 20, the common wiring 1081 in FIG. 4 is cut by a laser as indicated by a dotted line LS. Thereafter, the portion of the spare TFT 20 where the drain electrode 105 is overlapped with the cut common wiring 1081 is irradiated with laser to connect the cut common wiring 1081 and the source electrode 104 of the spare TFT 20. The portion irradiated with laser for connection corresponds to the portion of the arrow in FIG.

  Similarly, the cut common wiring 1081 and the video signal line 200 are connected by laser welding. Connection by laser welding is the same as described in FIG. Note that, when the common wiring 1081 is cut, it seems that no common voltage is applied to the common electrode 108 after that portion, but in reality, the common electrode 108 is connected to the common electrode on the right side of the figure via the common wiring 1081. 108, even if the common wiring 1081 is cut at one place, the common voltage is not applied to the common electrode 108.

  As described above, in this embodiment, when the spare TFT 20 is connected to the video signal line 200, the common line 1081 is used instead of a part of the scan line 300. Since it is not necessary to make it wide, an increase in capacitance between the video signal line 200 and the scanning line 300 can be suppressed.

  In addition, the capacitance is reduced by removing a part of the scanning line 300 at a portion where the video signal line 200 and the scanning line 300 intersect. Further, the capacitance is reduced by removing a part of the scanning line from under the drain electrode of the main TFT 10 and under the drain electrode of the spare TFT 20.

  Although the relationship between the source electrode and the pixel electrode of the spare TFT is not shown in FIG. 4, it may be configured as in the first embodiment or may be configured as in the third embodiment described later. . In FIG. 8, which is a BB cross-sectional view of FIG. 4, the connection between the source electrode and the pixel electrode of the spare TFT can be configured as in Example 3 described later.

  5 is a cross-sectional view taken along the line CC of FIG. In FIG. 5, scanning lines 300 and common wirings 1081 are arranged at a predetermined interval. The scanning line 300 and the common wiring 1081 are formed in the same layer at the same time. A common electrode 108 is formed on the TFT substrate by ITO, which is a transparent conductive film, and the common electrode 108 is connected to the common wiring 1081.

  8 is a cross-sectional view taken along the line BB in FIG. Scan lines 300 are formed on the TFT substrate. The scanning lines 300 are separated through slits, but this is for reducing the gate-drain capacitance, not for operating the spare TFT 20 as in the first embodiment.

  In FIG. 8, when operating the spare TFT 20, the drain electrode 105 of the spare TFT 20 and the common wiring 1081 are connected by laser welding indicated by an arrow. This point is different from the first embodiment. In FIG. 8, for example, the pixel electrode connection part 1101 described in the third embodiment and the source electrode 104 of the spare TFT 20 can be connected by laser welding in FIG. The other configurations in FIG. 8 are the same as those described with reference to FIG.

  As described above, according to this embodiment, it is possible to disconnect the defective main TFT 10 from the circuit and operate the spare TFT 20 while suppressing an increase in capacitance between the video signal line 200 and the scanning line 300. I can do it.

  FIG. 6 is a plan view showing a third embodiment of the present invention. In FIG. 6, the video signal line 200 extends in the vertical direction, and the scanning line 300 extends in the horizontal direction. A main TFT 10 and a spare TFT 20 are formed on the scanning line 300. Therefore, the scanning line 300 also serves as the gate electrode 101 of the main TFT 10 and the spare TFT 20, as in FIG.

  In FIG. 6, the first scanning branch line 301 that exists in FIG. 2 does not exist. In this embodiment, when a problem occurs in the main TFT 10, when the spare TFT 20 is connected to the pixel electrode 110, the pixel electrode connection portion 1101 formed by extending a part of the pixel electrode 110 is used, and the pixel electrode is used. The connection part 1101 and the source electrode 104 of the spare TFT 20 are connected. Note that the pixel electrode connection portion 1101 is formed at the same time as the pixel electrode 110 is formed because it is a part of the pixel electrode 110.

  The pixel electrode connection part 1101 and the source electrode 104 of the spare TFT 20 are connected by laser welding. The state of this connection is shown in FIG. In FIG. 7A, the pixel electrode 110 before connection and the source electrode 104 of the spare TFT 20 are insulated via the inorganic passivation film 106. On the other hand, as shown in FIG. Then, the pixel electrode connection portion 1101 and the inorganic passivation film 106 formed of ITO in the portion irradiated with the laser are evaporated.

  The source electrode 104 of the spare TFT 20 formed of the Al alloy also melts or evaporates, but the residue of the Al alloy remains and adheres to the wall of the hole formed by the laser, and the pixel electrode connection portion 1101 and the source electrode 104 of the spare TFT 20 Will be connected. That is, such laser welding is possible because the source electrode is made of an Al alloy.

  Returning to FIG. 6, since the pixel electrode 110 and the source electrode 104 of the spare TFT 20 are directly connected, the first scanning branch line 301 and the through hole 111 formed in the pixel as shown in FIG. The connection electrode 1051 to be connected to is unnecessary. Accordingly, it is possible to suppress an increase in the capacitance of the gate and the drain in the normal operation state in which the main transistor is operating.

  In the present invention, the scanning line hole 310 formed at the intersection of the video signal line 200 and the scanning line 300 is made larger than that in the first embodiment. In FIG. 6, unlike FIG. 2, the first scanning branch line 301 is not necessary. In other words, unlike FIG. 2, the slit formed in the scanning line 300 is unnecessary in FIG. Therefore, the resistance of the scanning line 300 can be reduced accordingly. That is, even if the resistance slightly increases at the intersection between the scanning line 300 and the video signal line 200, the increase in resistance can be suppressed for the entire scanning line 300. In the configuration of FIG. 6, since a large hole is formed in the scanning line 300 and the area where the scanning line 300 and the video signal line 200 overlap can be reduced, the capacity between the scanning line 300 and the video signal line 200 is reduced. I can do it.

  9 is a cross-sectional view taken along the line DD of FIG. In FIG. 9, a scanning line 300 and a second scanning branch line 302 are formed on the TFT substrate. When the second TFT is operated, laser welding is performed by applying a laser to the drain electrode portion of the second TFT as indicated by an arrow in FIG. Further, by irradiating the pixel electrode connecting portion 1101 extending from the pixel electrode 110 with a laser, as described in FIG. 7, the source electrode of the second TFT and the pixel electrode connecting portion 1101 are connected by laser welding. . The other configuration in FIG. 9 is the same as that described in FIG.

  Each embodiment in the above description has been described on the assumption of an IPS liquid crystal display device. However, the present invention is not limited to the IPS method, and can be applied to other types of liquid crystal display devices. Further, the TFT structure has been described as a so-called bottom gate type in which the gate electrode is below the semiconductor layer, but the present invention can be applied to a so-called top gate in which the gate electrode in the TFT structure is above the semiconductor. The invention can be applied. The source electrode 104, the drain electrode 105, and the scanning line 300 have been described using an example of an Al alloy, but other than the Al alloy, a Cu (copper) alloy, a Mo (molybdenum) alloy, a W (tungsten) alloy, Cr The present invention can be applied even if any of (chrome) alloys is used.

1 is a cross-sectional view of a liquid crystal display device of Example 1. FIG. 1 is a plan view of Example 1. FIG. 3 is a schematic diagram of laser welding in Example 1. FIG. 6 is a plan view of Example 2. FIG. 3 is a partial cross-sectional view of Example 2. FIG. 6 is a plan view of Example 3. FIG. 6 is a schematic diagram of laser welding in Example 3. FIG. 6 is a cross-sectional view of a liquid crystal display device of Example 2. FIG. 6 is a cross-sectional view of a liquid crystal display device of Example 3. FIG.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 10 ... Main TFT, 20 ... Spare TFT, 100 ... TFT substrate, 102 ... Gate insulating film, 103 ... Semiconductor layer, 104 ... Source electrode, 105 ... Drain electrode, 106 ... Inorganic passivation film, 108 ... Common electrode, 110 ... Pixel Electrode 111 ... Through hole 120 ... Alignment film 200 ... Video signal line 300 ... Scanning line 301 ... First scanning branch line 302 ... Second scanning branch line 310 ... Scanning line hole 1031 ... n + Si layer 1051... Connection electrode, 1081. Common wiring, 1101.

Claims (9)

The scanning lines extend in the first direction and are arranged in the second direction, the video signal lines extend in the second direction and are arranged in the first direction, and the scanning lines and the video signal lines A liquid crystal display device in which pixel electrodes are arranged in an enclosed area,
A first TFT and a second TFT are disposed on the scanning line,
The drain electrode of the first TFT is connected to the video signal line, the source electrode of the first TFT is connected to the pixel electrode,
The scanning line is divided into a first portion and a second portion by a first slit extending in a direction in which the scanning line extends, and the scanning line extends in a direction in which the scanning line extends. The second slit is divided into the second part and the third part,
The first portion of the scanning line extends under a connection electrode that is electrically connected to the pixel electrode, and the first portion of the scanning line and the connection electrode are insulated via an insulating layer. ,
A third portion of the scanning electrode extends below the video signal line, and the third portion of the scanning line and the video signal line are insulated via an insulating layer;
The channel portion of the second TFT is present on the second portion of the scan line;
The source electrode of the second TFT extends over the first portion of the scan line, and the source electrode of the second TFT and the first portion of the scan line are insulated via an insulating layer. Has been
The drain electrode of the second TFT extends over the third portion of the scan line, and the drain electrode of the second TFT and the third portion of the scan line are interposed via an insulating layer. A liquid crystal display device characterized by being insulated.   2. The liquid crystal display device according to claim 1, wherein the drain electrode and the source electrode of the second TFT are formed of any one of an Al alloy, a Cu alloy, a Mo alloy, a W alloy, and a Cr alloy. The scanning lines extend in the first direction and are arranged in the second direction, the video signal lines extend in the second direction and are arranged in the first direction, and the scanning lines and the video signal lines A liquid crystal display device in which pixel electrodes are arranged in an enclosed area,
A first TFT and a second TFT are disposed on the scanning line,
The drain electrode of the first TFT is connected to the video signal line, the source electrode of the first TFT is connected to the pixel electrode,
A common line extends in a first direction parallel to the scanning line;
The drain electrode of the second TFT extends over the common wiring, and the common wiring and the drain electrode of the second TFT are insulated via an insulating layer;
The liquid crystal display device, wherein the second TFT is in a float state.   A part of the scanning line is removed at the intersection of the scanning line and the video signal line, a part of the scanning line is removed under the drain electrode of the first TFT, and the second 4. The liquid crystal display device according to claim 3, wherein a part of the scanning line is removed under the drain electrode of the TFT. The scanning lines extend in the first direction and are arranged in the second direction, the video signal lines extend in the second direction and are arranged in the first direction, and the scanning lines and the video signal lines A liquid crystal display device in which pixel electrodes are arranged in an enclosed area,
A first TFT and a second TFT are disposed on the scanning line,
The drain electrode of the first TFT is connected to the video signal line, the source electrode of the first TFT is connected to the pixel electrode,
The scanning line is divided into a first part and a second part by a slit extending in a direction in which the scanning line extends,
A channel portion of the second TFT is present on the first portion of the scan line;
The second portion of the scanning line extends below the video signal line, and the second portion of the scanning line and the video signal line are insulated via an insulating layer,
A pixel electrode connection portion that is electrically connected to the pixel electrode extends to above the source electrode of the second TFT, and the pixel electrode connection portion and the source electrode of the second TFT are insulated via an insulating layer. A liquid crystal display device.   6. The liquid crystal display device according to claim 5, wherein the source electrode and the drain electrode of the second TFT are formed of any one of an Al alloy, a Cu alloy, a Mo alloy, a W alloy, and a Cr alloy. The scanning lines extend in the first direction and are arranged in the second direction, the video signal lines extend in the second direction and are arranged in the first direction, and the scanning lines and the video signal lines A liquid crystal display device in which pixel electrodes are arranged in an enclosed area,
A first TFT and a second TFT are disposed on the scanning line,
The drain electrode of the first TFT is connected to the video signal line, the source electrode of the first TFT is connected to the pixel electrode,
The scanning line is divided into a first portion and a second portion by a first slit extending in a direction in which the scanning line extends, and the scanning line extends in a direction in which the scanning line extends. The second slit is divided into the second part and the third part,
The first portion of the scanning line extends under a connection electrode that is electrically connected to the pixel electrode, and the first portion of the scanning line and the connection electrode are insulated via an insulating layer. ,
A third portion of the scanning electrode extends below the video signal line, and the third portion of the scanning line and the video signal line are insulated via an insulating layer;
The channel portion of the second TFT is present on the second portion of the scan line;
The source electrode of the second TFT extends over the first portion of the scan line, and the source electrode of the second TFT and the first portion of the scan line are insulated via an insulating layer. Has been
The drain electrode of the second TFT extends over the third portion of the scan line, and the drain electrode of the second TFT and the third portion of the scan line are interposed via an insulating layer. For insulated liquid crystal display devices
The source electrode and drain electrode of the first TFT are cut by a laser, the source electrode of the second TFT and the first portion of the scanning line are connected by laser welding, and the second TFT The drain electrode and the third portion of the scanning line are connected by laser welding, the first portion of the scanning line and the second portion of the scanning line are insulated by laser cutting, and the scanning A method of manufacturing a liquid crystal display device, wherein the third portion of the line and the second portion of the scanning line are insulated by laser cutting. The scanning lines extend in the first direction and are arranged in the second direction, the video signal lines extend in the second direction and are arranged in the first direction, and the scanning lines and the video signal lines A liquid crystal display device in which pixel electrodes are arranged in an enclosed area,
A first TFT and a second TFT are disposed on the scanning line,
The drain electrode of the first TFT is connected to the video signal line, the source electrode of the first TFT is connected to the pixel electrode,
A common line extends in a first direction parallel to the scanning line;
The drain electrode of the second TFT extends over the common wiring, and the common wiring and the drain electrode of the second TFT are insulated via an insulating layer;
For the liquid crystal display device in which the second TFT is in a float state,
The drain electrode of the first TFT is cut by a laser, the drain electrode of the second TFT and the common wiring are connected by laser welding at a first connection portion, and the video signal line and the common wiring are connected to the second TFT. Connected by laser welding at the connection of
A method of manufacturing a liquid crystal display device, wherein the common wiring is cut by a laser outside of the first connection portion and the second connection portion. The scanning lines extend in the first direction and are arranged in the second direction, the video signal lines extend in the second direction and are arranged in the first direction, and the scanning lines and the video signal lines A liquid crystal display device in which pixel electrodes are arranged in an enclosed area,
A first TFT and a second TFT are disposed on the scanning line,
The drain electrode of the first TFT is connected to the video signal line, the source electrode of the first TFT is connected to the pixel electrode,
The scanning line is divided into a first part and a second part by a slit extending in a direction in which the scanning line extends,
A channel portion of the second TFT is present on the first portion of the scan line;
The second portion of the scanning line extends below the video signal line, and the second portion of the scanning line and the video signal line are insulated via an insulating layer,
A pixel electrode connection portion that is electrically connected to the pixel electrode extends to above the source electrode of the second TFT, and the pixel electrode connection portion and the source electrode of the second TFT are insulated via an insulating layer. For liquid crystal display devices
The drain electrode and the source electrode of the first TFT are cut by a laser, the source electrode of the second TFT and the pixel electrode connection portion are connected by laser welding, and the drain electrode of the second TFT Connecting the second portion of the scan line by laser welding;
A method of manufacturing a liquid crystal display device, wherein the second portion of the scanning line is cut by a laser to insulate the first portion of the scanning line from the second portion of the scanning line.

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