JP2005115049A - Active matrix substrate - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an active matrix substrate superior in durability with respect to static electricity and reliability in the display operation. <P>SOLUTION: The active matrix substrate 1 is provided with a plurality of scan lines 3, a plurality of signal lines 4, a plurality of spare wiring pieces 7, and a pixel semiconductor element connected at each point of intersection between the scan line 3 and the signal line 4, for switching a drive signal for a pixel electrode, and is further provided with a TFT (thin-film transistor) element 10 for performing the switching so that each of the scan line 3, the signal line 4, and the spare wiring piece 7 is connected, when the drive signal is not entered into the substrate, and is disconnected, when the drive signal is entered into the substrate. Accordingly, when the drive signal is not entered, the substrate is protected from a high voltage applied thereto due to the static electricity. When the drive signal is inputted, the occurrence of leakage failure of the scan line 3 and the signal line 4 can be prevented. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to an active matrix substrate, and more particularly to an active matrix substrate that performs display by applying a driving voltage to a pixel electrode via a switching element and driving a liquid crystal by a potential difference with a counter electrode.

  2. Description of the Related Art Conventionally, in an active matrix liquid crystal display device, individual independent pixel portions are arranged in a matrix on a liquid crystal panel, and pixel electrodes and switching elements are provided in these pixel portions, respectively.

  The active matrix liquid crystal display device applies a driving voltage signal (driving signal) to a pixel electrode through a switching element, and the pixel electrode and a counter electrode arranged to face the pixel electrode through a liquid crystal The liquid crystal is driven by the potential difference between the first and second images, and the image is displayed on the liquid crystal panel by modulating the transmitted light or reflected light.

  In the liquid crystal display device, an MIM (Metal Insulator Metal) element or a TFT (Thin Film Transistor) element is used as a switching element. In particular, a liquid crystal panel using TFT elements is currently most widely used as an active matrix liquid crystal display device in terms of quality and cost.

  In the liquid crystal display device using the above TFT element, a scanning line for inputting a scanning signal for controlling the switching element and a driving signal for an image displayed on the liquid crystal panel are input to a pixel portion arranged in a matrix. Signal lines for input are arranged vertically and horizontally.

  In many liquid crystal display devices, when a scanning line or a signal line is defective, a spare wiring is provided so as to be connected to the scanning line or the signal line using a laser or the like.

  By the way, switching elements such as TFT elements are generally weak against strong electric fields. For this reason, when the static electricity which generate | occur | produces in the manufacturing process of a liquid crystal display device, a mounting process, etc. is input into a scanning line or a signal line undesirably, the said switching element may be destroyed (electrostatic destruction).

  The spare wiring is used when a scanning line or a signal line has a defect, and is originally installed in an electrically floating state. For this reason, the spare wiring has an extremely high impedance, and when a high voltage due to static electricity is applied, dielectric breakdown due to the high voltage is caused at the intersection with the scanning line or the signal line, resulting in an electrical failure. May occur. Even in the case where dielectric breakdown does not occur, the potential of the scanning line or signal line is pushed up to the vicinity of the potential of the spare wiring, and as a result, the operation of the switching element may be defective.

  Therefore, a protection circuit for connecting adjacent scanning lines or signal lines or a protection circuit for connecting spare wirings and scanning lines or signal lines may be provided in the vicinity of the input terminals of the scanning lines, signal lines, and spare wirings. Has been done. These techniques are disclosed in Patent Document 1, for example.

  FIG. 4 is a plan view schematically showing a configuration of a conventional active matrix substrate 51. The liquid crystal panel is configured by bonding an active matrix substrate 51 and a counter substrate 52 together with a sealing material (not shown), and enclosing liquid crystal (not shown) between the substrates 51 and 52.

  On the active matrix substrate 51, a plurality of scanning lines 53 and a plurality of signal lines 54 are arranged vertically and horizontally. Each area divided by the scanning line 53 and the signal line 54 becomes a pixel portion 55, and the pixel portion 55 is arranged in a matrix to constitute an effective display area 56.

  On the active matrix substrate 51, a plurality of spare wirings 57 are disposed on the input side and the non-input side of the signal line 54.

  Further, on the active matrix substrate 51, the scanning line input terminal 58, the signal line input terminal 59, and the terminal portion 63 of the spare wiring 57 are provided at the end of each scanning line 53, each signal line 54, and each spare wiring. Each is formed. The protection circuit 60 is disposed on the active matrix substrate 51 between the adjacent scanning lines 53, between the adjacent signal lines 54, between the adjacent spare wirings 57, between the preliminary wiring 57 and the scanning lines 53, and Provided between the spare wiring 57 and the signal line 54. All the protection circuits 60 have the same structure.

  FIG. 5 shows an electrical circuit diagram of the protection circuit 60. As shown in FIG. 5, the protection circuit 60 has a diode ring structure in which two diode-connected switching elements (semiconductor elements) 60a and 60b are connected in opposite directions and in parallel.

  As for the switching element 60a of the protection circuit 60, the source part and the gate part are short-circuited. Since the source part and the gate part are short-circuited, the switching element 60a functions as a diode. Both the source part and the gate part of the switching element 60a are electrically connected to the drain part of the switching element 60b and any one of the scanning line 53, the signal line 54, and the spare wiring 57. . The drain part of the switching element 60a is electrically connected to the wiring adjacent to the wiring to which both the source part and the gate part are connected, and is connected to the source part and the gate part of the switching element 60b. Yes.

  On the other hand, in the switching element 60b, the source part and the gate part are short-circuited. Since the source part and the gate part are short-circuited, the switching element 60b functions as a diode. Both the source part and the gate part of the switching element 60b are electrically connected to the drain part of the switching element 60a. The drain part of the switching element 60b is connected to the source part and the gate part of the switching element 60a.

  FIG. 6 shows a plan view of the protection circuit 60. Here, description will be made assuming that the protection circuit 60 is provided between the spare wiring 57 and the scanning line 53.

  As shown in FIG. 6, the switching element 60 a is configured by providing a semiconductor thin film 67 or the like on a metal film 65 a formed integrally with the spare wiring 57. A metal layer 69a serving as a source wiring is connected to the source portion of the semiconductor thin film 67, and a metal layer 69b serving as a drain wiring is connected to the drain portion. The metal layer 69 b is connected to a metal film 65 b formed integrally with the scanning line 53.

  On the other hand, the switching element 60 b is configured by providing a semiconductor thin film 67 or the like on a metal film 65 b formed integrally with the scanning line 53. A metal layer 69a serving as a source wiring is connected to the source portion of the semiconductor thin film 67, and a metal layer 69b serving as a drain wiring is connected to the drain portion. The metal layer 69b is connected to the metal film 65a.

  In the protection circuit 60 shown in FIG. 6, when the spare wiring 57 is charged by static electricity or the like, the charge is released to the scanning line 53 through the switching element 60a. When charge is generated in the scanning line 53, the charge is released to the spare wiring 57 through the switching element 60b.

  As described above, when a high voltage due to static electricity is applied to any one of the scanning line 53, the signal line 54, and the spare wiring 57, the protection circuit 60 causes the charge to flow into the other adjacent wiring, and the specific wiring Concentration of the electric field on the wiring can be avoided. Therefore, it is possible to prevent the occurrence of defects due to the above-described electrostatic breakdown. Furthermore, it is possible to prevent the above-described dielectric breakdown and increase of the potential of the signal line 4 at the intersection 64 between the spare wiring 57 and the signal line 4.

Further, as shown in FIG. 6, the channel length of the switching elements 60 a and 60 b of the protection circuit 60 is L, and the channel width is W. By changing the W / L ratio, the resistance values of the switching elements 60a and 60b functioning as diodes can be controlled.
Japanese Patent Laid-Open No. 11-271722 (publication date: October 8, 1999)

  However, in the above-described conventional configuration, the resistance value of the protection circuit 60 is set within a certain range in order to allow the charge to escape to other wirings and to perform the display operation without trouble even when used in the display device. There was a need.

  That is, static electricity applied to a certain wiring is discharged to the adjacent wiring according to the time constant determined by the resistance value of the protection circuit 60. It is important to make it as short as possible. From this point, it is desirable to set the resistance value of the protection circuit 60 as small as possible. On the other hand, in order for the liquid crystal display device to be driven without a problem in display and not to cause a problem in reliability, it is necessary to set a lower limit of a resistance value between signal lines or between scanning lines. By providing this lower limit, there was a limit to improving resistance to static electricity.

  In the conventional configuration, the protection circuit is designed and manufactured so that the W / L ratio becomes a predetermined value so that the resistance value of the protection circuit satisfies the lower limit. There was a problem that variation in the ratio had to be suppressed. This is because if there is a protective circuit with a large variation in W / L ratio and a low resistance value between signal lines or between scan lines, the drive signal leaks to the adjacent wiring.

  The present invention has been made in view of the above problems, and an object of the present invention is to provide an active matrix substrate having high resistance to static electricity and high reliability of display operation.

  In order to solve the above problems, an active matrix substrate of the present invention includes a plurality of scanning lines arranged in parallel, a plurality of signal lines arranged in parallel so as to intersect the scanning lines, In an active matrix substrate including a scanning line and each signal line and a pixel semiconductor element that is connected to each intersection of the scanning line and switches a driving signal to the pixel electrode, between the scanning line and each signal line, A switching element is provided that is connected when a drive signal is not input to the pixel electrode and that is switched off when a drive signal is input to the pixel electrode.

  In order to solve the above problems, an active matrix substrate of the present invention includes a plurality of scanning lines arranged in parallel and a plurality of signal lines arranged in parallel so as to intersect the scanning lines. A pixel semiconductor element that is connected to each scanning line and each signal line at each intersection thereof and performs switching of a driving signal to the pixel electrode, and at least one input side and non-input side of the scanning line or signal line In addition, in an active matrix substrate including a plurality of spare wirings arranged so as to intersect the scanning lines or the signal lines, a driving signal is supplied to the pixel electrode between the scanning lines, the signal lines, and the spare wirings. A switching element is provided which is connected when not inputted and switched so as to be cut off when a driving signal is inputted to the pixel electrode.

  As described above, the active matrix substrate according to the present invention connects between the scanning lines and the signal lines when no driving signal is input to the pixel electrode, and when the driving signal is input to the pixel electrode. A switching element that switches to shut off is provided.

  With the above configuration, when no drive signal is input to the pixel electrode, that is, when the display device is not lit when used in a display device, the scanning lines and the signal lines are connected and short-circuited. Therefore, even when a high voltage due to static electricity is applied to either the scanning line or the signal line, all the scanning lines and the signal line are discharged, so that a high voltage is not locally applied. As a result, the pixel semiconductor elements connected to the scanning lines and the signal lines are not destroyed by the high voltage, and electrostatic breakdown can be prevented.

  In the case of the above conventional configuration, it is necessary to provide a lower limit to the resistance value of the protection circuit. However, in this configuration, there is no such limitation, and when the drive signal is not input, the resistance value between the lines is reduced as much as possible. Can do. Therefore, the high voltage due to static electricity can be dispersed at a higher speed than before, and the resistance to static electricity can be further improved.

  Further, with the above configuration, when a drive signal is input to the pixel electrode, that is, when the display device is turned on when used in a display device, the scanning line and the signal line are disconnected (disconnected). Therefore, a drive signal input to one certain scanning line or signal line does not leak to other scanning lines or signal lines, and an electrical failure due to a leakage failure can be solved more reliably. Thereby, when used in a display device, the reliability of the display operation is improved.

  Therefore, it is possible to provide an active matrix substrate having high resistance to static electricity and high display operation reliability.

  In addition, as described above, the active matrix substrate according to the present invention has a plurality of spare lines arranged on the input side and the non-input side of at least one of the scanning lines or signal lines so as to intersect the scanning lines or signal lines. Switching that connects between the wiring and each of the scanning line, signal line, and spare wiring when the drive signal is not input to the pixel electrode and is switched off when the drive signal is input to the pixel electrode Device.

  By providing the spare wiring, when there is a defect in the scanning line or the signal line, the spare wiring can be connected to the defective line and repaired.

  In addition, with the above configuration, when a drive signal is not input to the pixel electrode, that is, when it is not lit when used in a display device, the scan lines, signal lines, and spare lines are connected and short-circuited. The Therefore, even if a high voltage due to static electricity is applied to any one of the scanning lines, signal lines, and spare wirings, all the scanning lines, signal lines, and spare wirings are discharged and no high voltage is locally applied. Can be. As a result, the pixel semiconductor elements connected to the scanning lines and the signal lines are not destroyed by the high voltage, and electrostatic breakdown can be prevented. Further, even when a high voltage due to static electricity is applied to the spare wiring, it is possible to prevent dielectric breakdown at the intersection between the spare wiring and the scanning line or the signal line, and to prevent the potential of the scanning line or the signal line from being pushed up.

  Further, with the above configuration, when a drive signal is input to the pixel electrode, that is, when the display device is turned on when used in a display device, the scanning line, the signal line, or the spare line is blocked. As a result, the electrical failure due to the leak failure can be solved more reliably, and the reliability of the display operation is improved.

  Therefore, it is possible to provide an active matrix substrate having high resistance to static electricity and high display operation reliability.

  An embodiment of the present invention will be described below with reference to FIG. FIG. 1 is a plan view schematically showing the configuration of the active matrix substrate 1 of the present embodiment.

  The active matrix substrate 1 is used for a liquid crystal panel of a liquid crystal display device. In the liquid crystal panel, an active matrix substrate 1 and a counter substrate 15 are bonded together by a sealing material (not shown), and the space between the substrates 1 and 15 is increased. The liquid crystal (not shown) is sealed in.

  On the active matrix substrate 1, a plurality of scanning lines 3 and a plurality of signal lines 4 are arranged so as to cross each other. Each region divided by the scanning line 3 and the signal line 4 becomes a pixel portion 5, and the effective display region 6 is configured by arranging the pixel portions 5 in a matrix.

  Further, a plurality of spare wirings 7 are arranged on the input side and the non-input side of the signal line 4 so as to cross the signal line 4. The spare wiring 7 is connected to the signal line 4 and repaired when a defect is found in one of the signal lines 4. Therefore, when there is no defect, the spare wiring 7 is not connected to the signal line 4.

  Further, when a high voltage due to static electricity is applied to one or a plurality of scanning lines 3, signal lines 4, and spare lines 7, the active matrix substrate 1 is protected to protect the active matrix substrate 1 from the high voltage. , Common wirings 16 and 17 and TFT elements 10 and 11 are provided. Detailed descriptions of the common wirings 16 and 17 and the TFT elements 10 and 11 will be described later.

  Further, on the active matrix substrate 1, scanning line input terminals 8 and signal line input terminals 9 are formed at the ends of the scanning lines 3 and the signal lines 4, respectively. , Terminals 13 are formed. Signals are input to the scanning line 3, the signal line 4, and the spare wiring 7 via the scanning line input terminal 8, the signal line input terminal 9, and the terminal 13, respectively.

  Further, the active matrix substrate 1 includes a region 19 that is removed from the active matrix substrate 1 by cutting the active matrix substrate 1 along the dividing line 2 after the lighting inspection is completed.

  In the active matrix substrate 1, a plurality of terminals 18, 12, and 14 for lighting inspection are provided in a region 19 outside the terminals 8, 9, and 13 where external circuits are to be mounted. A plurality of scanning lines 3 are electrically bundled and connected to each terminal 18 by a short-circuit wiring in order to perform a lighting inspection more easily, and the terminal 12 is also connected to perform a lighting inspection more easily. For example, it is divided into a plurality of terminals 12R, 12G, and 12B corresponding to each color of red (R), green (G), and blue (B). A plurality of signal lines 4 for R, G, and B are electrically bundled and connected to each terminal 12R, 12G, and 12B by short-circuit wiring. On the other hand, each terminal 14 is connected to a terminal 13 of the corresponding spare wiring 7.

  FIG. 2 is a plan view of the pixel portion 5 in the active matrix substrate 1 described above. As shown in the figure, in the region of the pixel portion 5 divided by the scanning lines 3 and the signal lines 4 in the active matrix substrate 1, there are TFT elements (semiconductor elements for pixels) 33, pixel electrodes 34, auxiliary capacitance wirings. 35, a contact hole 24, and a transparent conductive film 25 are formed.

  The scanning line 3 is connected to the gate electrode of the TFT element 33. A scanning signal for controlling the TFT element 33 is input to the scanning line 3 via the scanning line input terminal 8. In response to the scanning signal, the TFT element 33 switches ON / OFF.

  The signal line 4 is connected to the source electrode of the TFT element 33. A driving signal applied to the pixel electrode 34 is input to the signal line 4 via the signal line input terminal 9. The drive signal is input to the pixel electrode 34 via the signal line 4 and the TFT element 33.

  In the pixel portion 5 located at the intersection of the scanning line 3 to which the scanning signal is input and the signal line 4 to which the driving signal is input, the TFT element 33 is turned on and the driving signal is input to the pixel electrode 34. When the active matrix substrate 1 is used in a liquid crystal display device, when the drive signal is input to the pixel electrode 34, the pixel electrode 34 and a counter electrode (illustrated) arranged to face the pixel electrode 34 through the liquid crystal are illustrated. The liquid crystal is driven by the potential difference between the liquid crystal panel and the transmitted light or the reflected light, and an image is lit on the liquid crystal panel. Therefore, in order to cause a drive signal to be input to the pixel electrode 34 in any one of the pixel units 5 and to light it, both the scan signal and the drive signal are applied to the scan line 3 and the signal line 4 corresponding to the pixel unit 5. Must be entered.

  A pixel electrode 34 is connected to the drain electrode of the TFT element 33, and one terminal of the auxiliary capacitor of the pixel unit 5 is connected via the transparent conductive film 25. The auxiliary capacity wiring 35 functions as the other terminal of the auxiliary capacity. The auxiliary capacitance line 35 is connected to a counter electrode (not shown) arranged to face the pixel electrode 34. The pixel electrode 34 is connected to the drain electrode of the TFT element 33 through a contact hole 24 formed so as to penetrate an interlayer insulating film 32 described later.

The TFT element 33 has a configuration as shown in FIG. 3 and is formed as follows. A gate electrode 26 is formed on a transparent insulator substrate 31 made of glass or the like, and a gate insulating film 27 is formed so as to cover the gate electrode 26. A semiconductor thin film 28 is formed on the gate electrode 26 via a gate insulating film 27. A source electrode 29a made of an n ⁺ -silicon layer is formed on the source part of the semiconductor thin film 28, and a drain electrode 29b made of an n ⁺ -silicon layer is also formed on the drain part.

  A metal layer 30a serving as a source wiring is connected to the source electrode 29a, and a metal layer 30b serving as a drain wiring is connected to the drain electrode 29b. The surface of the TFT element 33 is covered with an interlayer insulating film 32. Further, a pixel electrode 34 is formed on the interlayer insulating film 32. The pixel electrode 34 is connected to the metal layer 30 b on the drain side of the TFT element 33 through the contact hole 24.

  Next, the characteristic structure in the active matrix substrate 1 of this embodiment for the purpose of protecting the substrate from high voltage application due to static electricity will be described.

  As shown in FIG. 1, the active matrix substrate 1 is provided between a common wiring 17 for short-circuiting each of the scanning lines 3, the signal lines 4, and the spare wiring 7, and between each wiring and the common wiring 17. A plurality of TFT elements 10, a common wiring 16 connected to the gate electrode of each TFT element 10, and a high level or a low level voltage applied to the gate electrode of each TFT element 10 via the common wiring 16. TFT element 11 is provided.

  The TFT element 10 is, for example, an n-channel MOS transistor, and when a voltage higher than a predetermined level (high level voltage) is applied to the gate electrode, the drain-source becomes conductive (ON state). On the other hand, when a voltage less than a predetermined voltage (low level voltage) is applied to the gate electrode, the drain-source is cut off (OFF state).

  The drain-source of the TFT element 10 is connected between the scanning line 3, the signal line 4, the spare wiring 7, and the common wiring 17. Therefore, when all the TFT elements 10 are turned on, the scanning lines 3, the signal lines 4, and the spare wirings 7 are connected. Conversely, when all the TFT elements 10 are turned off, the scanning lines 3, the signal lines 4, and the spare wirings 7 are disconnected. That is, the TFT element 10 is a switching element that switches between the scanning line 3, the signal line 4, and the spare wiring 7 between a connection state and a cutoff state in accordance with a signal input to the gate electrode.

  The common wiring 16 is connected to the gate electrode of each TFT element 10 and is also connected to the drain terminal of the TFT element 11.

  The TFT element 11 is provided for applying a high level or low level voltage to the gate electrode of each TFT element 10 through the common wiring 16, and is, for example, an n-channel MOS transistor. The drain terminal of the TFT element 11 is connected to the terminal 20 through the common wiring 16 and the resistor 21. A voltage having a predetermined value is applied to the terminal 20. The source terminal of the TFT element 11 is grounded. Further, a drive signal applied to the pixel electrode 34 via the TFT element 33 for lighting the pixel unit 5 is input to the gate terminal of the TFT element 11 at the same time as being applied to the pixel electrode 34.

  When a drive signal is input to the gate electrode of the TFT element 11, the drain-source is brought into conduction, and the drain terminal has a low level potential. Therefore, the TFT element 11 outputs a low level signal to the gate electrode of the TFT element 10 through the common wiring 16.

  On the other hand, when a drive signal is not input to the gate electrode of the TFT element 11, the drain-source is cut off, and the drain terminal has a high level potential. Therefore, the TFT element 11 outputs a high level signal to the gate electrode of the TFT element 10 via the common wiring 16.

  Thus, the TFT element 11 is wired so as to be a NOT circuit with respect to the input drive signal. It can be said that a drive signal is input to the gate electrode of the TFT element 10 via a NOT circuit.

  When the pixel unit 5 is turned on, that is, when a drive signal is input to the pixel electrode 34 and the TFT element 11, the TFT element 11 is connected to the gate electrode of the TFT element 10 via the common wiring 16 and a low level signal. Output voltage (OFF output). As a result, the drain and source of the TFT element 10 are cut off (OFF state), and the scanning line 3, the signal line 4, and the spare wiring 7 are disconnected. That is, the TFT element 10 switches between the scanning lines 3, the signal lines 4, and the spare wiring 7 when the driving signal is input to the pixel electrode 34.

  As a result, when the pixel unit 5 is lit, leakage current (leakage current) is not generated between the respective wirings, and electrical problems can be solved.

  When the pixel unit 5 is not lit, that is, when a drive signal is not input to the pixel electrode 34 and the TFT element 11, the TFT element 11 is connected to the gate electrode of the TFT element 10 through the common wiring 16 at a high level. Is output (ON output). As a result, the drain-source of the TFT element 10 becomes conductive (ON state), and the wirings of the scanning line 3, the signal line 4, and the spare wiring 7 are connected and short-circuited. That is, the TFT element 10 switches so that the scanning lines 3, the signal lines 4, and the spare wiring 7 are connected when no driving signal is input to the pixel electrode 34.

  As a result, when the pixel portion 5 is not lit, even if a high voltage is applied to one of the scanning line 3 and the signal line 4 due to static electricity, the high voltage is applied to the scanning line 3, the signal line 4, and It is distributed over all the lines of the spare wiring 7, and local high voltage application can be avoided. Thereby, the TFT element 33 connected to the scanning line 3 or the signal line 4 to which a high voltage is applied is not electrostatically destroyed.

  Further, even when a high voltage is applied to any one of the spare wirings 7 due to static electricity, the high voltage is distributed to all the scanning lines 3, the signal lines 4, and the spare wirings 7, and the local high voltage Application can be avoided. As a result, it is possible to prevent dielectric breakdown from occurring at the intersection between the spare wiring 7 and the signal line 4 to which a high voltage is applied.

  Further, it is possible to prevent the potential of the signal line 4 that intersects the spare wiring 7 to which a high voltage is applied from being raised. Thereby, characteristic deterioration of the TFT element 33 connected to the signal line 4 can be prevented.

  In the present embodiment, the spare wiring 7 is disposed on the input side and the non-input side of the signal line 4 so as to intersect the signal line 4. However, the spare wiring 7 may be arranged so as to intersect the scanning line 3 on the input side and the non-input side of the scanning line 3 in order to repair the defective scanning line 3. Furthermore, the scanning lines 3 and the signal lines 4 may be arranged on both the input side and the non-input side.

  In the present embodiment, the active matrix substrate 1 provided with the spare wiring 7 has been described. This is a preferable configuration that can be immediately repaired when the scanning line 3 or the signal line 4 is defective. However, the present invention is not limited to this, and only the scanning lines 3 and the signal lines 4 which are the minimum necessary configuration for lighting the pixel unit 5 are provided, and the spare wiring 7 may not be provided. In this case, the TFT element 10 switches between the scanning line 3 and the signal line 4 between a connected state and a cut-off state in accordance with the presence or absence of a drive signal input to the pixel electrode 34. In other words, the TFT element 10 connects between the scanning line 3 and the signal line 4 when the drive signal is not input to the pixel electrode 34 and blocks when the drive signal is input to the pixel electrode 34. Switch.

  In the present embodiment, the driving signal is input to the TFT element 11, but the configuration is not limited thereto, and a configuration in which a scanning signal is input may be used. The TFT element 11 outputs an OFF signal to the TFT element 10 when the driving signal is input to the pixel electrode 34, that is, when the pixel unit 5 is lit, and the driving signal is input to the pixel electrode 34. When there is no light, that is, when the pixel portion 5 is not lighted, an ON signal may be output to the TFT element 10. In order to light the pixel portion 5, it is necessary to simultaneously input the drive signal and the scan signal to the signal line 4 and the scan line 3, so that even if the TFT element 11 uses the drive signal, the scan signal is used. However, the same effect can be obtained.

  The active matrix substrate of the present invention can be applied to an active matrix liquid crystal display device because it has high resistance to static electricity and high display operation reliability.

1 is a plan view showing a configuration of an active matrix substrate according to an embodiment of the present invention. It is a top view of the pixel part in said active matrix substrate. FIG. 3 is a cross-sectional view taken along line A-A ′ in the pixel portion of FIG. 2. It is a top view which shows schematically the structure of the conventional active matrix substrate. It is a circuit diagram of the protection circuit provided in the conventional active matrix substrate. It is a top view of the said protection circuit.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Active matrix substrate 3 Scanning line 4 Signal line 7 Preliminary wiring 10 TFT element (switching element)
33 TFT elements (semiconductor elements for pixels)
34 Pixel electrode

Claims (2)

A plurality of scanning lines arranged in parallel, a plurality of signal lines arranged in parallel so as to intersect the scanning lines, and each scanning line and each signal line are connected to each other at each intersection, and a pixel In an active matrix substrate including a pixel semiconductor element that switches a drive signal to an electrode,
A switching element is provided that connects between the scanning line and the signal line when a drive signal is not input to the pixel electrode, and is switched to be cut off when the drive signal is input to the pixel electrode. Active matrix substrate. A plurality of scanning lines arranged in parallel, a plurality of signal lines arranged in parallel so as to intersect the scanning lines, and each scanning line and each signal line are connected to each other at each intersection, and a pixel A pixel semiconductor element for switching the drive signal to the electrode, and a plurality of spares arranged on at least one input side and non-input side of the scan line or signal line so as to intersect the scan line or signal line In an active matrix substrate comprising wiring,
A switching element is provided that connects between the scanning line, the signal line, and the spare wiring when the drive signal is not input to the pixel electrode, and is switched to be cut off when the drive signal is input to the pixel electrode. An active matrix substrate characterized by that.

Images