JP2005078048A - Active matrix substrate, active matrix substrate manufacturing method, and liquid crystal display device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an active matrix substrate, an active matrix substrate manufacturing method, and a liquid crystal display device capable of preventing electrostatic breakdown during rubbing processing.
An active matrix substrate includes a substrate, a pixel electrode provided on the substrate, and an auxiliary capacitor provided so as to correspond to the pixel electrode. The auxiliary capacitance is arranged between the auxiliary capacitance electrode electrically connected to the pixel electrode, the auxiliary capacitance common electrode arranged to face the auxiliary capacitance electrode, and the auxiliary capacitance electrode and the auxiliary capacitance common electrode. And a dielectric layer. The active matrix substrate further includes an auxiliary capacitor common line connected to the auxiliary capacitor common electrode, an upper conductive layer electrically connected to the auxiliary capacitor common line, and between the pixel electrode, the upper conductive layer, and the auxiliary capacitor. And an interlayer insulating layer provided. The upper conductive layer is provided on at least a part of the periphery of the display area defined by the pixel electrode.
[Selection] Figure 4

Description

  The present invention relates to an active matrix substrate used for a liquid crystal display device, and more particularly to an active matrix substrate subjected to a rubbing process.

  A liquid crystal display device generally has a structure in which a liquid crystal layer is disposed between an active matrix substrate and a counter substrate which are provided to face each other. An active matrix substrate generally has a thin film transistor (hereinafter referred to as TFT) 1 as a switching element as shown in FIG. In addition, an auxiliary capacitor (Cs capacitor) 2 is connected to the drain of the TFT 1 in order to hold the writing voltage of the pixel capacitor 3. FIG. 1 is an equivalent circuit diagram of one pixel of the liquid crystal display device, and shows a connection relationship between the TFT 1, the pixel capacitor 3 and the auxiliary capacitor 2.

  FIG. 2A shows a layout pattern of the liquid crystal display device corresponding to FIG. In FIG. 2, the counter electrode is omitted. FIG. 2B is a cross-sectional view corresponding to the line A0-A1-A2 in FIG.

  As shown in FIGS. 2A and 2B, the active matrix substrate includes gate wirings 4 arranged in a row direction (left-right direction in the figure) on a substrate 25 having a base coat film 29 formed on the main surface. The auxiliary capacitance common wiring 12, the source wiring 5 arranged in the column direction (vertical direction in the figure), and the pixel electrodes 6 arranged in a matrix form. A TFT 1 is provided in the vicinity of an intersection between the gate wiring 4 and the source wiring 5. The gate electrode 4a and the source electrode 5a of the TFT 1 are electrically connected to the gate wiring 4 and the source wiring 5, respectively. The drain electrode 28 of the TFT 1 is electrically connected to the pixel electrode 6 and the auxiliary capacitance electrode 7a.

  As shown in FIG. 2B, the pixel electrode 6 and the drain electrode 28 of the TFT 1 are electrically connected through a contact hole 9 provided in the interlayer insulating film 24. Further, the drain electrode 28 and the semiconductor layer 7 are electrically connected through a contact hole 8 provided in the interlayer insulating film 11 and the gate insulating layer 10. The source electrode 5 a is electrically connected to the semiconductor layer 7 through the contact hole 8.

  The auxiliary capacitance 2 includes an auxiliary capacitance common electrode 12a and an auxiliary capacitance electrode 7a facing each other, and a dielectric layer 10a disposed therebetween. The auxiliary capacitance common electrode 12a is composed of a common layer with the auxiliary capacitance common wiring 12, and the auxiliary capacitance common electrode 12a and the auxiliary capacitance common wiring 12 are electrically connected. The dielectric layer 10a of the auxiliary capacitor 2 is composed of a common layer with the gate insulating layer 10 of the TFT1. The auxiliary capacitance electrode 7a is composed of a common layer with the semiconductor layer 7 of the TFT 1, and the auxiliary capacitance electrode 7a and the semiconductor layer 7 are electrically connected.

  In the manufacturing process of the liquid crystal display device, in order to align the liquid crystal layer in a predetermined direction, a rubbing process is performed in which a polymer film provided on the substrate surface is rubbed with a rubbing cloth. When the active matrix substrate is rubbed, the rubbing cloth and the active matrix substrate are charged by friction. When the rubbing cloth charged with static electricity and the polymer film on the pixel electrode 6 come into contact with each other, the dielectric layer 10a of the auxiliary capacitor 2 undergoes electrostatic breakdown (ESD).

  This is because, due to the static electricity, an instantaneous large current flows through the pixel electrode 6, the source electrode 5a, the drain electrode 28, and the semiconductor layer 7 through the contact holes 8 and 9, thereby causing the dielectric layer 10a. This is because a local strong electric field is applied to the. Further, since the gate insulating layer 10 constituting the dielectric layer 10a is generally as thin as about 100 nm, the electric withstand voltage is low and breakdown due to static electricity is likely to occur.

  Furthermore, if the electric field applied by static electricity is too large, not only the dielectric layer 10a but also the interlayer insulating film 11 between the auxiliary capacitance common electrode 12a and the drain electrode 28, the auxiliary capacitance common electrode 12a and the pixel electrode 6 The interlayer insulating film 24 and the interlayer insulating film 11 between them may also be destroyed.

  In order to prevent the electrostatic breakdown, there is a method using a short ring for short-circuiting signal lines. Hereinafter, a description will be given with reference to FIG.

  The short ring (common wiring) 15 is provided around the mother substrate 16 before the plurality of active matrix substrates 14 are cut out. Since the short ring 15 is removed when the active matrix substrate 14 is cut out, the short ring 15 is formed outside the outer shape of the active matrix substrate 14. All signal lines 17 of the auxiliary capacitor common line, source line and gate line of each active matrix substrate are short-circuited by this short ring 15.

Further, in Patent Document 1, a conductive member is provided on the outer periphery of a display region in an active matrix substrate of a liquid crystal display device using an MIM element as a switching element, in order to prevent an insulating layer from being destroyed by static electricity generated during rubbing processing. It is disclosed.
JP-A-6-27495

  However, the above-described method of providing the short ring (FIG. 3) and the method of providing the conductive member (Patent Document 1) cannot sufficiently prevent the electrostatic breakdown of the insulating layer of the active matrix substrate.

  The present invention has been made to solve the above-described problems, and an object of the present invention is to provide an active matrix substrate, an active matrix substrate manufacturing method, and a liquid crystal display device that can prevent electrostatic breakdown during rubbing.

  The active matrix substrate of the present invention includes a substrate, a plurality of pixel electrodes provided on the substrate, and a plurality of auxiliary capacitors provided so as to correspond to the plurality of pixel electrodes. Each of the plurality of pixel electrodes, an auxiliary capacitance electrode electrically connected to each of the plurality of pixel electrodes, an auxiliary capacitance common electrode arranged to face the auxiliary capacitance electrode, and the auxiliary capacitance electrode and the auxiliary capacitance common A plurality of auxiliary capacitors having a dielectric layer disposed between the electrodes, an auxiliary capacitor common line connected to the auxiliary capacitor common electrode, and an upper conductive layer electrically connected to the auxiliary capacitor common line And a plurality of pixel electrodes and an interlayer insulating layer provided between the upper conductive layer and the plurality of auxiliary capacitors, wherein the upper conductive layer is a display area defined by the plurality of pixel electrodes. Provided on at least a portion of the peripheral, thereby the above problems can be solved.

  In one embodiment, the display region has a substantially rectangular shape including two sides adjacent to each other, and the upper conductive layer is provided along the two sides of the display region.

  In one embodiment, the upper conductive layer is provided so as to surround the display area.

  In one embodiment, an impurity adsorption electrode is provided around the display region.

  The manufacturing method of the active matrix substrate of the present invention includes a substrate, a plurality of pixel electrodes provided on the substrate, and a plurality of auxiliary capacitors provided so as to correspond to the plurality of pixel electrodes. Each of the storage capacitors includes a storage capacitor electrode electrically connected to each of the plurality of pixel electrodes, a storage capacitor common electrode disposed to face the storage capacitor electrode, the storage capacitor electrode, A plurality of auxiliary capacitors having a dielectric layer disposed between the auxiliary capacitor common electrode, an auxiliary capacitor common line connected to the auxiliary capacitor common electrode, and electrically connected to the auxiliary capacitor common line An upper conductive layer, the plurality of pixel electrodes, an interlayer insulating layer provided between the upper conductive layer and the plurality of auxiliary capacitors, and an alignment film provided to cover the plurality of pixel electrodes. And before The upper conductive layer is a method for manufacturing an active matrix substrate, which is provided in at least a part of the periphery of the display region defined by the plurality of pixel electrodes, and includes the step of forming the alignment film, The step of forming an alignment film includes (a) a step of forming a film so as to cover at least the plurality of pixel electrodes, and (b) a rubbing cloth before rubbing the film on the plurality of pixel electrodes. Contacting the rubbing cloth and the upper conductive layer, or contacting the rubbing cloth and the film disposed on the upper conductive layer; and (c) after the step (b), A step of orienting the surface of the film in a predetermined direction by rubbing the film, thereby solving the above-mentioned problems.

  The liquid crystal display device of the present invention includes a substrate, a plurality of pixel electrodes provided on the substrate, and a plurality of auxiliary capacitors provided to correspond to the plurality of pixel electrodes, wherein the plurality of auxiliary capacitors are provided. Each of the plurality of pixel electrodes, an auxiliary capacitance electrode electrically connected to each of the plurality of pixel electrodes, an auxiliary capacitance common electrode arranged to face the auxiliary capacitance electrode, and the auxiliary capacitance electrode and the auxiliary capacitance common A plurality of auxiliary capacitors having a dielectric layer disposed between the electrodes, an auxiliary capacitor common line connected to the auxiliary capacitor common electrode, and an upper conductive layer electrically connected to the auxiliary capacitor common line An interlayer insulating layer provided between the plurality of pixel electrodes and the upper conductive layer and the plurality of auxiliary capacitors, and an alignment film provided so as to cover the plurality of pixel electrodes, The upper conductive layer is the composite layer. The active matrix substrate is bonded to the active matrix substrate by an active matrix substrate provided in at least a part of the periphery of the display region defined by the pixel electrode and a sealing material disposed in a seal region around the active matrix substrate. And a liquid crystal layer disposed in a space surrounded by the active matrix substrate, the counter substrate and the sealing material, and the upper conductive layer is formed in the sealing region of the active matrix substrate. It arrange | positions inside and the said subject is solved by this.

  In one embodiment, the active matrix substrate has an impurity adsorption electrode disposed inside the seal region.

  The present invention provides an active matrix substrate, an active matrix substrate manufacturing method, and a liquid crystal display device that can prevent electrostatic breakdown during rubbing.

  Embodiments of an active matrix substrate according to the present invention will be described below with reference to the drawings.

(Embodiment 1)
4A is a schematic diagram showing a partial layout pattern of the active matrix substrate 100 of the present embodiment, and FIG. 4B is a cross-sectional view corresponding to the line A3-A4 in FIG. 4A. is there. FIG. 5 is an overall schematic diagram of the active matrix substrate 100. The cross-sectional view corresponding to the line A0-A1-A2 in FIG. 4A is the same as FIG. FIG. 6 is an equivalent circuit diagram of a liquid crystal display device including the active matrix substrate 100.

  As shown in FIG. 4A, the active matrix substrate 100 of the present embodiment is an auxiliary matrix provided so as to correspond to the substrate 25, the pixel electrodes 6 arranged in a matrix, and the plurality of pixel electrodes 6, respectively. And a capacity 2. The auxiliary capacitance 2 includes an auxiliary capacitance electrode 7a electrically connected to the pixel electrode 6, an auxiliary capacitance common electrode 12a disposed so as to face the auxiliary capacitance electrode 7a, an auxiliary capacitance electrode 7a, and an auxiliary capacitance common electrode 12a. And a dielectric layer 10a disposed between the two.

  The active matrix substrate 100 further includes an auxiliary capacitance common wiring 12 electrically connected to the auxiliary capacitance common electrode 12a, an upper conductive layer 22 electrically connected to the auxiliary capacitance common wiring 12, the pixel electrode 6 and An interlayer insulating layer 24 provided between the upper conductive layer 22 and the auxiliary capacitor 2 is provided. The upper conductive layer 22 is provided in a non-display area 35 provided around the display area 34. The upper conductive layer 22 is formed so as to completely surround the display region 34 as shown in FIG. Here, the display area 34 is defined by an area where a plurality of pixel electrodes 6 are arranged and substantially contributes to display. On the other hand, the non-display area 35 is an area provided around the display area 34 and provided with a drive circuit and a terminal, and does not substantially contribute to display. In FIG. 5, the display area 34 is indicated by an area surrounded by a dotted line 13.

  The active matrix substrate 100 further has an alignment film (not shown) on the outermost surface of the active matrix substrate so as to cover the pixel electrodes 6.

  This alignment film is formed using a rubbing method. Hereinafter, a method for forming the alignment film will be described.

  First, a predetermined film (for example, a polymer film such as a polyimide film) is formed on the substrate so as to cover the pixel electrode 6. The polymer film may be formed so as to cover the upper conductive layer 22 in addition to the pixel electrode 6. Next, the polymer film is rubbed using a rubbing roller. The rubbing roller is a rotating roll having a rubbing cloth attached to the surface. The polymer film is rubbed (rubbed) with a rubbing cloth by rotating the rubbing roller while moving the rubbing roller relative to the substrate 100. The rubbing roller is moved relative to the polymer film so as to be rubbed from the end (non-display area 35) of the active matrix substrate 100 toward the center.

  Through the above steps, the surface of the polymer film is aligned in a predetermined direction, and an alignment film is formed.

  In the active matrix substrate 100 of this embodiment, the upper conductive layer 22 is provided on the interlayer insulating layer 24 and in the non-display region 35 so as to completely surround the display region 34. Therefore, when the rubbing process is performed on the active matrix substrate 100, the rubbing cloth is disposed on the pixel electrode if the rubbing roller is moved relative to the substrate 100 from the end of the active matrix substrate 100 toward the center. Before rubbing the polymer film, the polymer film is in contact with the upper conductive layer 22 (when no polymer film is disposed on the upper conductive layer 22) or the polymer film disposed on the upper conductive layer 22 (When a polymer film is disposed on the upper conductive layer 22). That is, the conductor that first contacts the rubbing cloth charged with static electricity directly or via the polymer film is the upper conductive layer 22.

  When the rubbing cloth charged with static electricity contacts the upper conductive layer 22 or the polymer film on the upper conductive layer 22, the upper conductive layer 22 and the rubbing cloth tend to be at the same potential. Specifically, for example, when the rubbing cloth is positively charged by friction and the upper conductive layer 22 is negatively charged, the rubbing cloth and the upper conductive layer 22 tend to be at the same potential. Since the upper conductive layer 22 is electrically connected to the auxiliary capacitance common electrode 12 a via the auxiliary capacitance common wiring 12, the charge of the auxiliary capacitance common electrode 12 a is transferred to the upper conductive layer 22 via the auxiliary capacitance common wiring 12. Move and further move to the rubbing cloth. As described above, the upper conductive layer 22 and the rubbing cloth have the same potential. At the same time, the auxiliary capacitance common wiring 12 and the auxiliary capacitance common electrode 12a connected to the upper conductive layer 22, and the rubbing cloth and the upper conductive layer 22 have the same potential.

  As described above, after the rubbing cloth comes into contact with the upper conductive layer 22 or the polymer film disposed on the upper conductive layer 22, the rubbing cloth has the polymer film on the pixel electrode 6 and the upper conductive layer 22 or Contact with the polymer film on the upper conductive layer 22.

  When the polymer film on the pixel electrode 6 and the rubbing cloth come into contact with each other, the pixel electrode 6 tends to have the same potential as that of the upper conductive layer 22 and the rubbing cloth. As described above, the upper conductive layer 22 is electrically connected to the auxiliary capacitance common electrode 12a via the auxiliary capacitance common wiring 12, and the pixel electrode is electrically connected to the auxiliary capacitance electrode 7a. The auxiliary capacitance common electrode 12a and the auxiliary capacitance electrode 7a have the same potential. Accordingly, electrostatic breakdown of the dielectric layer 10a disposed between the auxiliary capacitance electrode 7a and the auxiliary capacitance common electrode 12a is prevented.

  On the other hand, when an upper conductive layer that is not electrically connected to the auxiliary capacitance common electrode 12a is formed, even if static electricity is generated between the rubbing cloth and the upper conductive layer, the potential of the auxiliary capacitance common electrode does not change. On the other hand, when the rubbing cloth charged with static electricity contacts the polymer film on the pixel electrode, the rubbing cloth and the pixel electrode are at the same potential, and the auxiliary capacitance electrode electrically connected to the pixel electrode is the same as the rubbing cloth. Become potential. Therefore, a potential difference is generated between the auxiliary capacitance electrode and the auxiliary capacitance common electrode, and the dielectric layer disposed between the auxiliary capacitance electrode and the auxiliary capacitance common electrode is electrostatically destroyed.

  Further, in the active matrix substrate 100 of the present embodiment, the upper conductive layer 22 is provided in the non-display region 35 in the active matrix substrate 100, so that the dielectric layer is more in comparison with the active matrix substrate having the short ring shown in FIG. The electrostatic breakdown of the body layer 10a can be further prevented. Details will be described below.

  As shown in FIG. 3, since the short ring 15 is removed when the mother substrate is divided into a plurality of active matrix substrates, the short ring 15 is formed outside the outer shape of the active matrix substrate. When the rubbing cloth 30 is inserted in the direction of the arrow 23 with respect to the mother board 16, and the rubbing cloth 30 charged with static electricity and the portion 37 of the short ring 15 come into contact with each other due to frictional charging between the rubbing cloth 30 and the mother board 16. The potentials of the rubbing cloth 30 and the short ring 15 are about to be the same. Therefore, as indicated by an arrow 18 in FIG. 3, the charge of the auxiliary capacitance common electrode 12 a moves through the short ring 15 toward the rubbing cloth 30.

  However, since the short ring 15 is formed outside the outer shape of the active matrix substrate as described above, the distance from the auxiliary capacitance common electrode 12a to the short ring 15 is the upper conductive layer from the auxiliary capacitance common electrode 12a of the present embodiment. Longer than the distance up to 22. Specifically, for example, in the 3.7 type panel, the charge transfer distance from the auxiliary capacitance common electrode 12a to the short ring 15 is about 15 mm to 200 mm, and is about 2 kΩ to 5 kΩ in terms of wiring resistance value. In the case of this embodiment, the charge transfer distance from the auxiliary capacitance common electrode 12a to the upper conductive layer 22 is about 0.1 mm to 28 mm, and is about 10Ω to 2 kΩ in terms of wiring resistance value. Further, when the conventional short ring 15 is used, if the size of the active matrix substrate is increased, the charge transfer distance becomes significantly longer.

  As described above, in the active matrix substrate 100 of the present embodiment, the charge transfer distance is shorter than that of the conventional one, so that the potential difference between the auxiliary capacitance common electrode 12a and the auxiliary capacitance electrode 7a is sufficiently reduced in the rubbing process. Therefore, it is possible to prevent electrostatic breakdown of the dielectric layer 10a disposed between the auxiliary capacitance common electrode 12a and the auxiliary capacitance electrode 7a as compared with the conventional case.

  Hereinafter, the active matrix substrate 100 of Embodiment 1 will be described in more detail.

  As shown in FIGS. 2A, 4A, and 4B, the active matrix substrate 100 is arranged in the row direction on the substrate 25 on which the base coat film 29 is formed on the main surface. The gate wiring 4 and the auxiliary capacitance common wiring 12 and the source wiring 5 arranged in the column direction are provided. A switching element such as TFT 1 is provided in the vicinity of the intersection of the gate wiring 4 and the source wiring 5. The base coat film 29 can be omitted.

  The gate electrode 4a and the source electrode 5a of the TFT 1 are electrically connected to the gate wiring 4 and the source wiring 5, respectively. The drain electrode 28 of the TFT 1 is electrically connected to the pixel electrode 6 and the auxiliary capacitance electrode 7 a through the contact hole 9.

  The capacitive element 2 is formed by a dielectric layer 10a, and an auxiliary capacitance common electrode 12a and an auxiliary capacitance electrode 7a facing each other with the dielectric layer 10a interposed therebetween. In the present embodiment, as shown in FIG. 4A, the auxiliary capacitance common electrode 12 a is formed of a common layer with the auxiliary capacitance common wiring 12. 4A and 2A, the auxiliary capacitance electrode 7a is formed of a common layer with the semiconductor layer 7 of the TFT 1, and the dielectric layer 10a is formed with the gate insulating layer 10 of the TFT 1. It is formed of a common layer.

  The TFT 1 is not limited to the top gate type illustrated in FIG. 2A, and may be, for example, a bottom gate type. Further, the configuration of the capacitive element 2 is not limited to the configuration shown in FIGS. 2 (a) and 4 (a). The auxiliary capacitance common electrode 12 a only needs to be electrically connected to the auxiliary capacitance common wiring 12, and may be formed of a conductive layer different from the auxiliary capacitance common wiring 12. The auxiliary capacitance electrode 7 a may also be formed of a conductive layer different from the semiconductor layer 7. 4A illustrates the case where the auxiliary capacitance electrode 7a is disposed on the substrate 25 side with respect to the auxiliary capacitance common electrode 12a. However, the auxiliary capacitance common electrode 12a is closer to the substrate 25 than the capacitance electrode 7a. It may be arranged on the side.

  The electrical connection between the auxiliary capacitance common electrode 12a and the upper conductive layer 22 is formed as follows, for example.

  As shown in FIG. 4B, the auxiliary capacitance line 12 electrically connected to the auxiliary capacitance common electrode 12a is formed to extend in the row direction, and extends to the lower portion of the upper conductive layer 22 in the non-display area 35. It is extended. Between the upper conductive layer 22 and the auxiliary capacitance wiring 12, the interlayer insulating layer 11, the lower conductive layer 20, and the interlayer insulating layer 24 are formed in this order from the substrate 25 side. A contact hole 19 and a contact hole 39 are provided in the interlayer insulating layer 11 and the interlayer insulating layer 24, respectively. The auxiliary capacitance common electrode 12a and the upper conductive layer 22 are electrically connected to each other through the auxiliary capacitance wiring 12, the contact hole 19, the lower conductive layer 20, and the contact hole 39.

  The upper conductive layer 22 (and the lower conductive layer 20) is formed so as to surround the pixel display region 34, as shown in FIG. A predetermined DC or AC voltage is applied to the upper conductive layer 22 through the wiring 27 and the terminal pad 26 in order to maintain the voltage applied to the pixel capacitor. For example, the same voltage as the common voltage (on the opposite substrate side) is applied to the upper conductive layer 22.

  The upper conductive layer 22 is formed in the same process using, for example, the same material (for example, ITO) as the pixel electrode 6. The lower conductive layer 20 is formed in the same process using, for example, the same material as the gate wiring 5.

  As shown in FIGS. 4 and 5, the active matrix substrate 100 has an impurity adsorption electrode composed of an upper layer impurity adsorption electrode 21 and a lower layer impurity adsorption electrode 31.

  In the case of manufacturing a liquid crystal display device using the active matrix substrate 100, the active matrix substrate 100 and the counter substrate provided with the common electrode are bonded to each other with a sealing material, and the active matrix substrate 100, the counter substrate, and the sealing material are surrounded. A liquid crystal material is injected into the region. The sealing material is formed in a sealing region around (the end part) of the active matrix substrate 100 and the counter substrate.

  In a liquid crystal display device, ionic impurities may be dissolved into a liquid crystal layer from a sealing material or a color filter. In addition, the liquid crystal material itself may contain impurities. When the liquid crystal layer contains the impurities, there is a problem that display quality is deteriorated, such as display unevenness and a decrease in contrast ratio.

  If the impurity adsorption electrode is provided on the active matrix substrate 100, the impurity can be adsorbed on the impurity adsorption electrode. Therefore, impurities can be prevented from being mixed into the liquid crystal layer in the display region, so that deterioration in display quality of the liquid crystal display device can be suppressed.

  The upper conductive layer 22 is preferably provided inside the seal region of the active matrix substrate 100. This is because the charge transfer distance from the auxiliary capacitance common electrode 12a to the upper conductive layer 22 can be shortened compared to the case where the charge is provided outside the seal region, and the charge existing in the auxiliary capacitance common electrode 12a can be easily transferred. In addition, since the upper conductive layer 22 can be prevented from coming into contact with the outside air (atmosphere), the upper conductive layer 22 is not corroded. Furthermore, the size of the substrate can be reduced.

  Hereinafter, the impurity adsorption electrode will be described more specifically.

  The impurity adsorption electrode includes an upper layer impurity adsorption electrode 21 and a lower layer impurity adsorption electrode 31. The upper impurity adsorption electrode 21 and the lower impurity adsorption electrode 31 are electrically connected via the contact hole 9. The impurity adsorption electrodes 21 and 31 are formed, for example, so as to surround the display region 34 between the upper conductive layer 22 and the display region 34 in the non-display region 35. Further, the impurity adsorption electrodes 21 and 31 are provided in the non-display region 35 on the substrate center side (display region 34 side) with respect to the seal region of the substrate 100. As shown in FIG. 5, the impurity adsorption electrodes 21 and 31 are applied with a DC voltage (for example, about 8 to 12 V), for example, via the wiring 33 and the terminal pad 26 when the liquid crystal display device is driven.

  The impurity adsorption electrodes 21 and 31 may be provided only in a part of the periphery of the display region 34. However, if the impurity adsorption electrodes 21 and 31 are formed so as to surround the display region 34 as shown in FIG. Impurities can be more completely prevented from entering the display area 34 from the non-display area 35.

  The impurity adsorption electrode can be omitted. FIG. 7 shows a schematic diagram of an active matrix substrate 100A having no impurity adsorption electrode.

(Embodiment 2)
FIG. 8 is a schematic plan view of the active matrix substrate 102 of the second embodiment.

  In the active matrix substrate 100 of the first embodiment, the upper layer electrode 22 is formed in the non-display area 35 so as to surround the entire display area 34, whereas in the active matrix substrate 102 of the second embodiment, the upper layer electrode 22 is formed. Is formed only in a part of the periphery of the display area 34.

  In the active matrix substrate 102, the structure other than the upper layer electrode 22 is the same as that of the active matrix substrate 100.

  In the active matrix substrate 102 according to the second embodiment, the upper conductive layer 22 is formed along two sides of the display region 34 that intersects the rubbing direction. That is, the upper conductive layer 22 is formed along two sides adjacent to one corner of the rectangular display region 34, and is substantially diagonal from one corner of the active matrix substrate 102 in the direction of the arrow 23 in FIG. The rubbing is performed in the direction (the rubbing input direction is the upper left as viewed from the front of the substrate).

  Even when the upper layer electrode 22 is formed only in a part of the periphery of the display region 34 as in the active matrix substrate 102, if the upper layer conductive layer 22 is formed in a predetermined region in consideration of the rubbing direction, the rubbing is performed. In the process, the rubbing cloth can be brought into contact with the upper conductive layer 22 or the polymer film on the upper conductive layer before the rubbing cloth and the polymer film on the pixel electrode 6 come into contact with each other. Therefore, since the charge of the auxiliary capacitance common electrode 12a can be moved toward the rubbing cloth, the electrostatic breakdown of the dielectric layer 10a can be prevented as in the first embodiment.

  The place where the upper conductive layer 22 is formed is not limited to that illustrated in FIG. For example, when rubbing in a direction parallel to the extending direction of any side of the active matrix substrate 102, the upper conductive layer 22 along one side (upstream side in the rubbing direction) of the display region 34 intersecting the rubbing direction. May be formed.

  Note that the direction of inserting the rubbing cloth can be known by measuring the tilt direction of the liquid crystal molecules of the liquid crystal display device.

  The present invention is suitably used for an active matrix substrate for a liquid crystal display device that performs a rubbing process.

It is an equivalent circuit diagram of one pixel of a general liquid crystal display device. (A) is a schematic diagram which shows the layout pattern of the liquid crystal display device corresponding to FIG. 1, (b) is sectional drawing corresponding to the A0-A1-A2 line of (a). It is a figure for demonstrating the conventional short ring. (A) is a schematic diagram which shows the layout pattern of the active matrix substrate of Embodiment 1 of this invention, (b) is sectional drawing corresponding to the A3-A4 line of (a). 1 is a schematic diagram of an active matrix substrate of Embodiment 1. FIG. 2 is an equivalent circuit diagram of a liquid crystal display device including the active matrix substrate of Embodiment 1. FIG. 6 is a schematic diagram of an active matrix substrate of a modification example of Embodiment 1. FIG. 6 is a schematic diagram of an active matrix substrate of Embodiment 2. FIG.

Explanation of symbols

1 TFT
2 Auxiliary Capacitor 3 Pixel Capacitance 4 Gate Wiring 4a Gate Electrode 5 Source Wiring 5a Source Electrode 6 Pixel Electrode 7 Semiconductor Layer 7a Auxiliary Capacitance Electrode 8 Contact Hole 9 Contact Hole 10 Gate Insulating Layer 10a Dielectric Layer 11 Interlayer Insulating Layer 12 Auxiliary Capacitor Common Wiring 12a Auxiliary capacitance common electrode 14 Active matrix substrate 15 Short ring 16 Mother substrate 17 Signal line 20 Lower conductive layer 21 Upper layer impurity adsorption layer 22 Upper conductive layer 24 Interlayer insulating layer 25 Substrate 26 Terminal pad 27 Wiring 28 Drain electrode 29 Base coat film 30 Rubbing cloth 31 Lower layer impurity adsorption layer 33 Wiring 34 Display area 35 Non-display area 36 Charge 100 Active matrix substrate 102 Active matrix substrate

Claims (7)

A substrate,
A plurality of pixel electrodes provided on the substrate and a plurality of auxiliary capacitors provided so as to correspond to the plurality of pixel electrodes, wherein each of the plurality of auxiliary capacitors is each of the plurality of pixel electrodes An auxiliary capacitance electrode electrically connected to the auxiliary capacitance electrode, an auxiliary capacitance common electrode arranged to face the auxiliary capacitance electrode, and a dielectric layer arranged between the auxiliary capacitance electrode and the auxiliary capacitance common electrode A plurality of auxiliary capacities,
A storage capacitor common line connected to the storage capacitor common electrode;
An upper conductive layer electrically connected to the auxiliary capacitance common wiring;
An interlayer insulating layer provided between the plurality of pixel electrodes and the upper conductive layer and the plurality of auxiliary capacitors;
The upper conductive layer is an active matrix substrate provided on at least a part of a periphery of a display region defined by the plurality of pixel electrodes. The display area has a substantially square shape including two sides adjacent to each other,
The active matrix substrate according to claim 1, wherein the upper conductive layer is provided along the two sides of the display region.   The active matrix substrate according to claim 1, wherein the upper conductive layer is provided so as to surround the display region.   The active matrix substrate according to claim 1, further comprising an impurity adsorption electrode around the display area. A substrate,
A plurality of pixel electrodes provided on the substrate and a plurality of auxiliary capacitors provided so as to correspond to the plurality of pixel electrodes, wherein each of the plurality of auxiliary capacitors is each of the plurality of pixel electrodes An auxiliary capacitance electrode electrically connected to the auxiliary capacitance electrode, an auxiliary capacitance common electrode arranged to face the auxiliary capacitance electrode, and a dielectric layer arranged between the auxiliary capacitance electrode and the auxiliary capacitance common electrode A plurality of auxiliary capacities,
A storage capacitor common line connected to the storage capacitor common electrode;
An upper conductive layer electrically connected to the auxiliary capacitance common wiring;
An interlayer insulating layer provided between the plurality of pixel electrodes and the upper conductive layer and the plurality of auxiliary capacitors;
An alignment film provided to cover the plurality of pixel electrodes,
The upper conductive layer is a method for manufacturing an active matrix substrate, which is provided at least at a part of the periphery of a display region defined by the plurality of pixel electrodes,
Including the step of forming the alignment film, the step of forming the alignment film,
(A) forming a film so as to cover at least the plurality of pixel electrodes;
(B) Before the rubbing cloth rubs the film on the plurality of pixel electrodes, the rubbing cloth and the upper conductive layer are brought into contact with each other, or disposed on the rubbing cloth and the upper conductive layer. Contacting the applied membrane;
(C) A method of manufacturing an active matrix substrate, including the step of orienting the surface of the film in a predetermined direction by rubbing the film after the step (b). A substrate,
A plurality of pixel electrodes provided on the substrate and a plurality of auxiliary capacitors provided so as to correspond to the plurality of pixel electrodes, wherein each of the plurality of auxiliary capacitors is each of the plurality of pixel electrodes An auxiliary capacitance electrode electrically connected to the auxiliary capacitance electrode, an auxiliary capacitance common electrode arranged to face the auxiliary capacitance electrode, and a dielectric layer arranged between the auxiliary capacitance electrode and the auxiliary capacitance common electrode A plurality of auxiliary capacities,
A storage capacitor common line connected to the storage capacitor common electrode;
An upper conductive layer electrically connected to the auxiliary capacitance common wiring;
An interlayer insulating layer provided between the plurality of pixel electrodes and the upper conductive layer and the plurality of auxiliary capacitors;
An alignment film provided to cover the plurality of pixel electrodes,
The upper conductive layer is provided on at least a part of the periphery of the display area defined by the plurality of pixel electrodes;
A counter substrate bonded to the active matrix substrate by a sealing material disposed in a sealing region around the active matrix substrate;
A liquid crystal layer disposed in a space surrounded by the active matrix substrate, the counter substrate, and the sealing material;
The upper conductive layer is a liquid crystal display device disposed inside the seal region of the active matrix substrate. The liquid crystal display device according to claim 6, wherein the active matrix substrate has an impurity adsorption electrode disposed inside the seal region.

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