JP2008170987A - In-plane switching type liquid crystal display device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a high-quality in-plane switching type liquid crystal display device having a wide opening by suppressing a crosstalk by enhancing a shielding effect against a leakage electric field from a scanning line and reducing a light shielding region.
In an in-plane switching type liquid crystal display device, a drive electrode 5 and a counter electrode 6 are formed in the same layer on a protective film 10 formed in a layer above the scanning line 2 and the signal line 3, and the counter electrode 6 is formed. A projection surface on the substrate side of a part close to the scanning line 2 is formed to be enlarged above the scanning line 2 so as to fill a gap with the scanning line 2.
[Selection] FIG.

Description

  The present invention relates to an in-plane switching type (hereinafter referred to as IPS type) liquid crystal display device that drives a liquid crystal by generating an electric field parallel to an array substrate, and more particularly, leakage from wiring. The present invention relates to a structure of a high-brightness liquid crystal display device in which an aperture ratio is increased by reducing the influence of an electric field and reducing a light shielding region.

  In an active matrix liquid crystal display device, an in-plane switching method (that is, an IPS method) in which the direction of an electric field applied to the liquid crystal is parallel to the array substrate is mainly used as a method for obtaining a wide viewing angle. (For example, refer to Patent Document 1). It has been clarified that when this method is employed, there is almost no change in contrast and inversion of gradation levels when the viewing angle direction is changed (see Non-Patent Document 1, for example).

JP-A-8-254712 M.Oh-e, etc., AsiaDisplay, 95, pp. 577-580

  FIG. 18 schematically shows the structure of one pixel of a conventional IPS liquid crystal display device. FIG. 18 (a) is a plan view thereof, and FIG. 18 (b) is a cross-sectional view of FIG. It is sectional drawing in A '. FIG. 19 is an equivalent circuit of one pixel constituting the pixel electrode of the IPS liquid crystal display device, and FIG. 20 is a circuit configuration diagram illustrating a circuit of the IPS liquid crystal display device. In FIG. 18, 1 is a glass substrate, 2 is a scanning line, 3 is a signal line, 4 is a thin film transistor (TFT), 5 is a drive electrode, 6 is a counter electrode, 7 is a storage capacitor, 8 is a common wiring, and 9 is gate insulation. Films 10 and 10 are protective films, 11 is a liquid crystal, 12 is a black matrix (BM), 14 is a contact hole, 15 is a source electrode, and 16 is a drain electrode. Reference numeral 20 denotes an array substrate (comprised of a glass substrate 1, a signal line 3, a drive electrode 5, a counter electrode 6 and the like), 30 denotes a counter substrate disposed facing the array substrate 20, and 40 denotes a signal line 3. And the counter electrode 6, 50 is an opening. 19 and 20, the same reference numerals as those in FIG. 18 represent the same or equivalent elements as those in FIG.

  The schematic configuration and operation of a conventional IPS liquid crystal display device will be described with reference to FIGS. In FIG. 20, the scanning line 2 connected to the scanning line driving circuit and the signal line 3 connected to the signal line driving circuit intersect at almost right angles, so that a plurality of grids surrounded by the scanning line 2 and the signal line 3 are obtained. Shaped pixels. A thin film transistor (TFT Thin-Film-Transistor) is provided at each intersection of the scanning line 2 and the signal line 3 forming the lattice-like pixel.

  FIG. 19 shows this state by an equivalent circuit. The thin film transistor (TFT) 4 is a semiconductor element having three electrodes, a gate electrode, a source electrode 15, and a drain electrode 16. The gate electrode is connected to the scanning line 2 extending from the scanning line driving circuit, and the source electrode 15 is driven by a signal line. Connected to the signal line 3 connected to the circuit. The remaining drain electrode 16 is connected to the drive electrode 5 and drives the liquid crystal by an electric field generated between the counter electrode 6. Reference numeral 13 denotes a storage capacitor that holds electric charges between the drive electrode 5 and the counter electrode 6. Next, the structure of one pixel will be described with reference to FIGS. 18 (a) and 18 (b). A pixel formed by intersecting the scanning line 2 and the signal line 3 is provided with a driving electrode 5 and a counter electrode 6 for driving the liquid crystal layer, and a thin film transistor (TFT) 4. The thin film transistor (TFT) 4 has three electrodes, and the scanning line 2 connected to the scanning line driving circuit shown in FIG. 20 is connected to the gate electrode of the thin film transistor (TFT) 4 and the scanning line driving circuit outputs it. A scanning signal to be applied is applied to the gate electrode of the thin film transistor (TFT) 4.

  The signal line 3 connected to the signal line driving circuit is connected to the source electrode 15 of the thin film transistor 4 (TFT) and transmits a video signal output from the signal line driving circuit. The drain electrode 16 of the thin film transistor (TFT) 4 is connected to the drive electrode 5 through the contact hole 14 as shown in FIG. In the same pixel, the counter electrode 6 is provided so as to face and mesh with the drive electrode 5. The counter electrode 6 is connected to the common wiring 8. The common wiring 8 connects the counter electrode 6 provided in each pixel on the array substrate 20.

  Next, the structure of the pixel cross section will be described with reference to FIG. Reference numeral 1 denotes a glass substrate, on which a drive electrode 5 and a counter electrode 6 are formed. The same layer as the drive electrode 5 and the counter electrode 6 is not shown in FIG. 18B. The scanning line 2 and the common wiring 8 are also formed. Next, the gate insulating film 9 is laminated, and the signal line 3 is formed on the gate insulating film 9. Although not shown in FIG. 18B, the storage capacitor forming electrode 7 is also formed in the same layer as the signal line 3. A protective film 10 is further laminated on the signal line 3 to form an array substrate 20. The array substrate 20 and the counter substrate 30 are overlaid, and the liquid crystal 11 is sealed between the array substrate 20 and the counter substrate 30 to manufacture an IPS liquid crystal display device.

  Since the IPS liquid crystal display device is a method of driving an liquid crystal by generating an electric field along the surface of the array substrate 20 between the drive electrode 5 and the counter electrode 6 provided on the array substrate 20, the counter substrate 30 is An electrodeless substrate without electrodes. The counter substrate 30 is provided with a black matrix (BM) 12 that is a light-shielding film. Although not shown, the backlight provided on the lower side of the array substrate in FIG. Light leaking from the gap 40 is shielded.

  A region surrounded by a broken line 50 indicates an opening per pixel, and plays a role of a window through which light having a backlight as a light source is transmitted. However, the light from the backlight is blocked by the drive electrode 5, the counter electrode 6, the black matrix 12, and the like, and as a result, the image quality of the liquid crystal display is greatly affected. Therefore, it is a problem to reduce the ratio of the area of the drive electrode 5, the counter electrode 6, the black matrix 12, and the like occupying the area of the opening 50.

  The configuration of the pixel of the conventional IPS liquid crystal display device has been described with reference to FIGS. Next, the operation of the IPS liquid crystal display device will be described. A thin film transistor (TFT) 4 provided in each pixel and having a gate electrode connected to the scanning line 2, a source electrode 15 connected to the signal line 3, and a drain electrode 16 connected to the drive electrode 5 is a semiconductor switching element. Is controlled. When a scanning signal is applied to the gate electrode of the thin film transistor (TFT) 4 from the scanning line driving circuit via the scanning line 2, all the thin film transistors (TFT) 4 in the row are switched on.

  When the gate electrode is switched on, the video signal transmitted from the signal line drive circuit flows to the drain electrode 16 via the source electrode 15 and is written to the drive electrode 5 connected to the drain electrode 16. The charge written to the drive electrode 5 is held between the counter electrode 6 and the current charge is held until the gate electrode is turned on again and a new video signal charge is written. In other words, the drive electrode 5 and the counter electrode 6 function as a kind of capacitor in that charges are written while the gate electrode is turned on, and the written charges are stored as they are when the gate electrode is turned off. Plays. The storage capacitor 13 shown in FIG. 19 increases the storage power of the capacitor. The storage capacitor 13 is formed by stacking the storage capacitor forming electrode 7 and the common wiring 8 with the gate insulating film 9 interposed therebetween. .

  By the way, in the conventional IPS type liquid crystal display device shown in FIG. 18, between the signal line 3 provided at the side edge of one pixel and the counter electrode 6 formed in parallel with the signal line 3. An electric field is generated due to the potential difference between the signal line 3 and the counter electrode 6. FIG. 21 shows an electric field generated between the signal line 3 and the counter electrode 6 of a conventional IPS liquid crystal display device having an array substrate in which the drive electrode 5 and the counter electrode 6 are formed below the signal line 3. It is a figure which shows the influence which it has on the electric field which generate | occur | produces between the drive electrode 5 and the counter electrode 6, and was obtained by simulating the change of the electric potential generate | occur | produced between the drive electrode 5 and the counter electrode 6. FIG. FIG. 21 shows the calculation of the potential at the upper or lower portion of the window when a white window is displayed in a halftone with a relative transmittance of 50%.

  The drive electrode 5 is formed between the two counter electrodes 6 and it is desirable for the liquid crystal to be driven accurately that the potential distribution is symmetrical about the drive electrode 5. Referring to FIG. 21, the potential distribution in the region near the signal line 3 of the opening 50 is strongly influenced by the leakage electric field from the electric field generated between the signal line 3 and the counter electrode 6, and the potential distribution is You can see that it is asymmetric. This electric field is generated along the surface of the glass substrate 1 and causes problems such as crosstalk. For example, when a white window is displayed in a black display as shown in FIG. 22, a display problem called “vertical crosstalk” occurs in which the luminance at the top and bottom of the window changes with respect to the other black display. To do.

  Hereinafter, an example of a normally black mode (a mode in which black is displayed when no voltage is applied) will be described with reference to FIG. When the window pattern as shown in FIG. 22 is displayed, the signal line 3 of the pixel in the window portion and the upper and lower portions of the window in the screen is opposed to the opposite electrode 6 during the selection period of the black display portion. 6 is applied, and a voltage necessary for white display is applied during the selection period of the white display portion.

  It is considered that a voltage having a value obtained by averaging the absolute value of the potential difference between the electrodes is effectively applied to the liquid crystal 11. Therefore, for example, when the black display selection period and the white display selection period are the same, an effective potential equal to that in the halftone display is applied between these signal lines 3 and the counter electrode 6. At this time, the liquid crystal above the gap 40 between the signal line 3 and the counter electrode 6 is in a transmission mode by an electric field in a direction parallel to the glass substrate 1 generated between the signal line 3 and the counter electrode 6. Furthermore, the electric field generated by the potential difference between the signal line 3 and the counter electrode 6 also affects the electric field between the drive electrode 5 and the counter electrode 6, and changes the liquid crystal in the black display portion to the transmission mode. As a result, crosstalk occurs.

  In order to prevent the occurrence of such vertical crosstalk, leakage light transmitted through the gap 40 between the signal line 3 and the counter electrode 6 is blocked by a black matrix 12 (hereinafter abbreviated as BM) formed on the counter substrate 30. In addition, the drive electrode 5 and the counter electrode 6 are separated from the counter electrode 6 and the signal line 3 at the end on the opening 50 side, and an electric field generated between the signal line 3 and the counter electrode 6 is generated between the drive electrode 5 and the counter electrode 6. It is necessary to prevent interference with the electric field between them. However, when the drive electrode 5 and the counter electrode 6 are separated from the signal line 3 and the width of the counter electrode 6 adjacent to the signal line 3 is increased, the aperture ratio of the opening 50, that is, surrounded by a broken line in FIG. The ratio of the area obtained by subtracting the area of the drive electrode 5 and the counter electrode 6 from the area of the opening 50 to the area of the opening 50 is reduced, and the image quality is deteriorated. Therefore, in order to develop a high-quality liquid crystal display device, it is a problem to shield the electric field generated between the signal line 3 and the counter electrode 6 adjacent to the signal line 3 without reducing the aperture ratio. It was.

  Further, as apparent from FIG. 18B, the surface of the protective film 10 which is the upper layer film of the array substrate 20 has a step, and the distance (gap) from the counter substrate 30 is not constant. Therefore, uneven brightness tends to occur, causing deterioration in image quality. Further, since the step portion is provided, not only a defect due to a crack or the like of the array substrate 20 occurs during manufacturing, but also the wiring on the array substrate 20 may be disconnected at the step portion, so that the yield rate and reliability of the product are increased. There was a problem in improving.

  In addition, light having a backlight as a light source is transmitted as leakage light from the gap 40, and the image quality is deteriorated. A black matrix 12 is provided on the counter substrate 30 in order to shield this leakage light. However, when the array substrate 20 and the counter substrate 30 are overlapped, an error may occur. In consideration of this error, the black matrix 12 is formed large with a slight margin. However, when the black matrix 12 is enlarged to enhance the light shielding effect, there is a problem that the aperture ratio decreases.

  The present invention has been made to solve the above-described problems, and in an IPS liquid crystal display device using an electric field in a direction parallel to a glass substrate, the shielding effect against a leakage electric field from a wiring is enhanced and light shielding is performed. A first object is to provide a high-quality liquid crystal display device having a wide opening (that is, a high aperture ratio) by reducing the area. It is a second object of the present invention to provide a high-quality liquid crystal display device by improving the yield rate by suppressing the occurrence of defects such as cracks in the array substrate 20 and disconnection of wiring, thereby reducing the production cost. Is.

  An IPS type liquid crystal display device according to the present invention comprises a plurality of pixels arranged in a matrix, comprising scanning lines for transmitting scanning signals, signal lines for transmitting video signals, and regions surrounded by the scanning lines and the signal lines. A thin film transistor provided in the pixel region, connected to the scanning line and the signal line, for switching a video signal based on a scanning signal, a driving electrode connected to the thin film transistor, and facing the driving electrode An array substrate having a counter electrode disposed thereon, a counter substrate provided to face the array substrate, and being sealed between the array substrate and the counter substrate, wherein the drive electrode and the counter electrode are Liquid crystal that is driven by generating an electric field parallel to the substrate surface, and the drive electrode and the counter electrode are disposed above the scanning line and the signal line. The counter electrode is formed in the same layer on the protective film formed on the substrate, and the projection surface on the substrate side of the part close to the scanning line is placed above the scanning line so as to fill the gap with the scanning line. The counter electrode is formed so as to surround the drive electrode in each of the pixel regions, and the counter electrode of each pixel region adjacent to the pixel region in the scanning line direction and the pixel region And the counter electrode of each pixel region adjacent in the signal line direction and the counter electrode of the pixel region are connected.

  In the IPS type liquid crystal display device according to the present invention, the projection surface on the substrate side of the part close to the signal line of the counter electrode is formed to extend above the signal line so as to fill the gap with the signal line. To do.

  In the IPS liquid crystal display device according to the present invention, the projection surface on the substrate side of the portion adjacent to the scanning line and the signal line of the counter electrode has a lattice shape covering the entire surface of the scanning line and the signal line. It is.

  In the IPS liquid crystal display device according to the present invention, the projection surface on the substrate side of the portion close to the scanning line of the counter electrode is formed to extend above the thin film transistor.

  In the IPS liquid crystal display device according to the present invention, the drain electrode of the thin film transistor has an enlarged electrode portion that forms a storage capacitor.

  In the IPS liquid crystal display device according to the present invention, the common wiring is formed in the same layer as the scanning line, and the signal line is formed in a layer above the common wiring and the scanning line.

  In the IPS liquid crystal display device according to the present invention, the counter electrode is connected to the common line through the contact hole in each of the pixel regions.

  The IPS liquid crystal display device according to the present invention has a terminal portion, and the uppermost layer film of the terminal portion is formed in the same layer as the drive electrode and the counter electrode.

  In the IPS liquid crystal display device according to the present invention, the protective film has a flat shape made of resin.

  According to the IPS liquid crystal display device of the present invention, since the drive electrode and the counter electrode are formed in a layer close to the liquid crystal different from the signal line, the liquid crystal can be driven more efficiently. Accordingly, it is possible to widen the distance between the drive electrode and the counter electrode, and the aperture ratio can be improved.

  In addition, since the projection surface on the substrate side of the portion close to the scanning line of the counter electrode is formed on the scanning line so as to fill the gap with the scanning line, it is formed from the gap between the counter electrode and the scanning line. Not only can light leakage be prevented, but also the influence of the leakage electric field generated from the scanning line on the liquid crystal can be suppressed.

  Further, in each of the pixel regions, the counter electrode is formed so as to surround the drive electrode, and the counter electrode is connected to the counter electrode of the pixel region adjacent in the scanning line direction and the signal line direction. The width of the counter electrode can be increased without reducing the area of the opening. Therefore, the resistance of the counter electrode can be lowered, and the wiring load can be reduced. In addition, even if a disconnection occurs in the counter electrode, the potential is supplied from the counter electrode in contact with the counter electrode in another pixel region, so that it is possible to suppress the occurrence of display defects and improve reliability.

  Further, according to the IPS type liquid crystal display device of the present invention, the projection surface onto the substrate in the part close to the signal line of the counter electrode is formed to be enlarged above the signal line so as to fill the gap with the signal line. Therefore, not only can light leakage from the gap between the counter electrode and the signal line be prevented, but also the influence of the leakage electric field generated from the signal line on the liquid crystal can be suppressed.

  Further, according to the IPS type liquid crystal display device of the present invention, the projection surface on the substrate side of the portion close to the scanning line and the signal line of the counter electrode has a lattice shape covering the entire surface of the scanning line and the signal line. The leakage electric field from the scanning line and the signal line can be efficiently shielded, and the influence of the leakage electric field on the liquid crystal can be suppressed.

  According to the IPS liquid crystal display device of the present invention, since the projection surface on the substrate side of the portion close to the scanning line by the counter electrode is formed on the thin film transistor, the counter electrode is a light shielding film of the thin film transistor. And the light leakage of the thin film transistor can be suppressed.

  According to the IPS liquid crystal display device of the present invention, since the drain electrode of the thin film transistor has an enlarged electrode portion that forms the storage capacitor, the storage capacitor can hold the charge (voltage) of the drive electrode and the counter electrode. .

  According to the IPS liquid crystal display device of the present invention, the common wiring is formed in the same layer as the scanning line, and the signal line is formed in an upper layer than the common wiring and the scanning line. Defects can be suppressed.

  Further, according to the IPS type liquid crystal display device of the present invention, the counter electrode is connected to the common wiring through the contact hole in each of the pixel regions. Further, the common electrode formed on the substrate can be further suppressed, the resistance is further lowered, and the load is reduced, so that driving can be facilitated.

  Further, according to the IPS liquid crystal display device of the present invention, the uppermost layer film of the terminal portion can be formed in the same layer as the drive electrode and the counter electrode, so that the manufacturing process can be reduced.

  According to the IPS liquid crystal display device of the present invention, since the protective film has a flat shape made of resin, the gap between the surface of the array substrate and the counter substrate is accurately and uniformly formed over the entire display screen. In addition, the rubbing treatment required for the alignment of the liquid crystal is uniformly performed, and the alignment disorder can be reduced, so that a liquid crystal display device with less luminance unevenness can be realized over the entire display screen. In addition, the defect occurrence rate due to cracks or the like in the step portion of the protective film is reduced, and the yield can be improved.

Embodiment 1 FIG.
Hereinafter, an embodiment will be described with reference to the drawings. In the figure, the same reference numerals as in the prior art represent the same or equivalent ones as in the prior art. FIG. 1 is a sectional view schematically showing the structure of one pixel of an IPS liquid crystal display device according to Embodiment 1, and FIG. 2 is a plan view thereof. 1 shows a cross-sectional view taken along the line AA shown in FIG. In the figure, 1 is a glass substrate, 2 is a scanning line, 3 is a signal line, 4 is a thin film transistor (TFT), 5 is a drive electrode, 6 is a counter electrode, 7 is a storage capacitor, 8 is a common wiring, 9 is a gate insulating film Reference numeral 10 denotes a protective film, 11 denotes a liquid crystal, 12 denotes a black matrix (BM), 14 denotes a contact hole, 15 denotes a source electrode of the transistor, and 16 denotes a drain electrode of the transistor. Reference numeral 20 denotes an array substrate (consisting of a glass substrate 1, a signal line 3, a drive electrode 5, a counter electrode 6, etc.), 30 denotes a counter substrate serving as a display screen disposed facing the array substrate 20, and 40 Is a gap between the signal line 3 and the counter electrode 6, and 50 is an opening of the pixel. 3 shows an IPS liquid crystal display device in which a channel protective film type thin film transistor 21 which is a kind of thin film transistor 4 (TFT) is provided as the thin film transistor 4 (TFT) used in the IPS liquid crystal display device shown in FIG. FIG. 3A is a plan view, and FIG. 3B is a cross-sectional view.

  Next, the structure of the pixel of the IPS liquid crystal display device will be described with reference to FIGS. In the figure, reference numeral 1 denotes a glass substrate, and a scanning line 2 is formed on the glass substrate 1. A gate insulating film 9 is laminated so as to cover the scanning line 2, and the signal line 3 is provided on the gate insulating film 9. A protective film 10 is laminated on the signal line 3, and a drive electrode 5 and a counter electrode 6 are provided on the protective film 10. The array substrate 20 has a structure as described above. The substrate 30 provided so as to face the array substrate 20 is a counter substrate that sandwiches the liquid crystal 11 with the array substrate 20. The IPS liquid crystal display device generates an electric field along the surface of the array substrate 20 and drives the liquid crystal 11 by controlling the direction of the electric field.

  FIG. 2 is a plan view of the IPS liquid crystal display device shown in FIG. In FIG. 2, 2 is a scanning line, 3 is a signal line, and a region surrounded by the scanning line 2 and the signal line 3 is one pixel. Reference numeral 4 denotes a thin film transistor (TFT) provided at the intersection of the scanning line 2 and the signal line 3. Of the three electrodes of the thin film transistor 4, the gate electrode is connected to the scanning line 2 and the source electrode 15 is connected to the signal line 3. ing. Of the three electrodes of the thin film transistor 4, the drain electrode 16 is connected to the drive electrode 5 through the contact hole 14 in the upper layer through the protective film 10 (not shown). The counter electrode 6 is provided so as to be engaged with the drive electrode 5, and the counter electrode 6 is formed in the same layer as the common wiring 8 and connected to each other. Although not shown, the common wiring 8 connects the counter electrode 6 of another adjacent pixel. The drive electrode 5, the counter electrode 6, and the common wiring 8 are simultaneously formed in a layer above the signal line 3.

  Reference numeral 7 denotes a storage capacitor for holding the potential of the drive electrode 5, which is formed by laminating the counter electrode 6 and the drain electrode 16 vertically. Reference numeral 40 denotes a gap between the signal line 3 and the counter electrode 6, and the black matrix 12 provided on the counter substrate 30 shown in FIG. 1 blocks leakage light transmitted through the gap 40 using a backlight as a light source. is there. Reference numeral 50 denotes an opening. If the area of the opening is increased, a high-quality liquid crystal display can be obtained. Note that the IPS liquid crystal display device holds the electric charge written to the drive electrode 5 connected to the drain electrode 16 of the thin film transistor 4 between the drive electrode 5 and the counter electrode 6 provided on the array substrate 20, and is made of glass. Since the liquid crystal 11 is driven by generating an electric field along the surface of the substrate 1, the counter substrate 30 is an electrodeless substrate without electrodes. Hereinafter, an example of the process flow of the array substrate constituting the pixels of the IPS liquid crystal display device according to the first embodiment will be described.

  4, 5, and 6 are diagrams showing the process flow of the array substrate. 4 to 6 are diagrams showing the array substrate, and the diagram on the right side is a diagram showing a terminal portion for mounting the scanning line 2 on the scanning line driving circuit. In FIG. 4, in step 1, the scanning line 2 is formed on a glass substrate 1 as a simple substance such as Cr, Al, Mo, Ta, Cu, Al—Cu, Al—Si—Cu, Ti, W, or an alloy thereof, or A transparent material such as ITO (Indium Tin Oxide) or a structure in which these are laminated is formed with a thickness of about 50 nm to 800 nm. This scanning line 2 also functions as a gate electrode of the thin film transistor 4. As an etching method when forming the scanning line 2, taper etching having a trapezoidal cross section is shown in FIG. 4 as an example, but an etching method having a rectangular cross section may be used.

  In step 2, the gate insulating film 9, amorphous silicon, and amorphous silicon doped with impurities such as phosphorus are continuously deposited so as to cover the scanning line 2, and then the amorphous silicon is patterned to form the thin film transistor 4 in a channel etch type. is there. The gate insulating film 9 is made of a transparent insulating film such as silicon nitride or silicon oxide, an oxide film of a gate electrode material (that is, a material of the scanning line 2), or a laminated film thereof, and the thickness is about 200 nm to 600 nm. Is appropriate. Further, microcrystalline silicon doped with impurities such as phosphorus may be used instead of amorphous silicon doped with impurities such as phosphorus.

  In step 3, the signal line 3 is formed simultaneously with the source electrode 15 and the drain electrode 16 of the thin film transistor 4. The signal line 3 also functions as the source electrode 15. This signal line 3 is made of Cr, Al, Mo, Ta, Cu, Al—Cu, Al—Si—Cu, Ti, W alone, an alloy containing these as a main component, a transparent material such as ITO, or the like. It is formed with a laminated structure. In step 4, the protective film 10 is formed of a transparent insulating film such as silicon nitride or silicon oxide, and a part of the protective film on the drain electrode 16 of the thin film transistor 4 is used to electrically connect the drive electrode 5 and the drain electrode 16. Is removed to form a contact hole 14. At the same time, the gate insulating film 9 and the protective film 10 are removed from the terminal portion of the scanning line 2 and the protective film 10 is removed from the terminal portion of the signal line 3 so that the external circuit can be electrically connected to the scanning line 2 and the signal line 3. To do.

  In step 5, the drive electrode 5 and the counter electrode 6 are made of Cr, Al, Mo, Ta, Cu, Al—Cu, Al—Si—Cu, Ti as electrodes for forming an electric field in the horizontal direction with respect to the substrate surface. , W alone, an alloy thereof, a transparent material such as ITO, a structure in which these are laminated, or a laminated structure including these. The drive electrode 5 is connected to the drain electrode 16 through the contact hole 14. The counter electrode 6 is connected to the common wiring 8. The counter electrode 6 is overlapped with the drain electrode 16 through the protective film 10 to form a storage capacitor 7 for holding the potential of the drive electrode 5. Through the above five steps, the array substrate 20 having the drive electrode 5 and the counter electrode 6 above the signal line 3 (that is, on the counter substrate 30 side) and can apply an electric field in the horizontal direction to the substrate surface is A channel etch type thin film transistor can be used in the photolithography process.

  In the process flow of the array substrate described above, the terminals are formed using the same metal layer as the scanning lines 2, but the terminals may be formed using ITO. The ITO may be formed in the same layer as the scanning line 2, the signal line 3, or the common wiring 8. Further, although the signal wiring 3 is straight etched, it is desirable to perform taper etching. Further, when the signal line 3 is formed with a structure in which Al is laminated on Cr, if the Cr is patterned after patterning Al, the overetching is applied to the Cr, so that it becomes a wrinkle structure and causes breakage. In order to prevent this, if the Al is etched again after the Cr patterning and the Al is receded from the end face of the Cr, it is possible to prevent the formation of the eaves structure. For the etching of Al, taper etching may be used. In this method, the signal line 3 is different from Cr, Al, Mo, Ta, Cu, Al—Cu, Al—Si—Cu, Ti, W alone, an alloy mainly composed of these, or a transparent material such as ITO 2. It can be applied to the case where it is formed with a laminated structure of metals of more than kinds.

  In FIG. 4, the drive electrode 5 and the counter electrode 6 are formed in the same layer. However, as shown in FIG. 5, the drive electrode 5 is formed simultaneously with the signal line 3, and then the protective film 10 is formed using silicon nitride or the like. The counter electrode 6 may be formed after the formation. In this case, the drive electrode 5 and the counter electrode 6 are formed in separate layers. Further, instead of the thin film transistor 4 (TFT) used in the array substrate 20 shown in FIG. 4, a channel protective film type transistor 21 which is a kind of the thin film transistor 4 may be used. FIG. 6 is a diagram showing a process flow of the array substrate formed using the channel protective film type transistor 21.

  The array substrate 20 shown in FIG. 6 constitutes the pixel of the IPS type liquid crystal display device shown in FIG. 3, and has more layers than the array substrate 20 shown in FIG. This is because, after the scanning line 2 is formed, a gate insulating film 9, amorphous silicon, and a channel protective film are continuously deposited so as to cover the scanning line 2, and then a channel protective film 21 is formed, and the channel protective film 21 is used as a mask. Impurities such as P are ion-implanted into amorphous silicon to form an n layer to form a channel protective film transistor (step 2 in FIG. 6).

  The characteristic structure of the array substrate 20 of the IPS-type liquid crystal display device according to the first embodiment is that the drive electrode 5 and the counter electrode 6 are on the array substrate 20 above the signal line 3 (that is, on the counter substrate 30 side). It is arranged. With this arrangement, the formation of the contact hole 14 and the step of removing the protective film 10 from the terminal portion of the signal line 3 and the step of removing the insulating film 9 and the protective film 10 from the terminal portion of the scanning line 2 are performed at once. I can do it. Therefore, the number of masks can be reduced by one and the manufacturing cost can be reduced.

  Further, since the drive electrode 5 and the counter electrode 6 are formed in a layer on the counter substrate 30 side with the signal line 3 being different from the layer, the opening shown in FIG. 2 can be estimated as will be described later in Embodiment 5. It has been found that the influence of the electric field generated by the potential difference between the counter electrode 6 provided adjacent to the signal line 3 at the end of the part 50 and the signal line 3 can be reduced. Therefore, the counter electrode at the end of the opening 50 can be brought close to the signal line 3, and the area of the opening 50 can be increased.

  In FIG. 1, since the drive electrode 5 and the counter electrode 6 are in direct contact with the liquid crystal sandwiched between the array substrate 20 and the counter substrate 30, the liquid crystal can be driven efficiently. The interval between the electrodes 6 can be widened. Therefore, the effect that the aperture ratio is further improved can be obtained.

Embodiment 2. FIG.
FIG. 7 schematically shows the structure of the pixel electrode of the liquid crystal display device according to the second embodiment. FIG. 7 (a) is a plan view thereof, and FIG. 7 (b) is an A view of FIG. 7 (a). FIG. 8 is a diagram showing a process flow of the array substrate. In the figure, 1 is a glass substrate, 2 is a scanning line, 3 is a signal line, 4 is a thin film transistor (TFT), 5 is a drive electrode, 6 is a counter electrode, 7 is a storage capacitor, 8 is a common wiring, and 9 is a gate insulating film. 10 is a protective film, 11 is a liquid crystal, 12 is a black matrix, 14 is a contact hole, 15 is a source electrode of the transistor, 16 is a drain electrode of the transistor, and 18 is a through hole. Reference numeral 20 denotes an array substrate (consisting of a glass substrate 1, a signal line 3, a drive electrode 5, a counter electrode 6, etc.), 30 denotes a counter substrate serving as a display screen disposed facing the array substrate 20, and 40 Is a gap between the signal line 3 and the counter electrode 6, and 50 is an opening of the pixel.

  In the first embodiment, the common wiring 8 is formed in the same layer as the counter electrode 6. However, in the second embodiment, as shown in FIG. 8, the common wiring 8 is formed on the same layer as the scanning line 2, that is, on the glass substrate 1. A common wiring 8 is formed. The source electrode 15 is connected to the signal line 3, the signal line 3 is formed on the scanning line 2 and the common wiring 8 through the gate insulating film 9, and further the drive electrode 5 through the protective film 10. A counter electrode 6 is formed. The drive electrode 5 is connected to the drain electrode 16 through the contact hole 14, and the counter electrode 6 is connected to the common wiring 8 through the through hole 18. As for the thin film transistor (TFT) 4, a channel protective film type thin film transistor may be used.

  In the IPS liquid crystal display device according to the second embodiment, the drive electrode 5 and the counter electrode 6 are formed in a layer close to the liquid crystal different from the signal line 3 as in the first embodiment, so that the liquid crystal is driven more efficiently. Therefore, the aperture ratio can be improved by increasing the distance between the drive electrode 5 and the counter electrode 6. Further, since the common wiring 8 and the scanning line 2 are formed in the same layer, the common wiring 8 is formed on the flat glass substrate 1 together with the scanning line 2, and the common wiring 8 is disconnected at the step portion. Can be suppressed, and the occurrence of defect rate can be reduced. Therefore, the reliability of the product is also improved. In the first embodiment, the counter electrode 6 cannot be thinned because the resistance of the common wiring 8 is lowered. However, in the second embodiment, the counter electrode 6 can be thinned. By reducing the thickness of the counter electrode 6, variations in electrode spacing are reduced, and a liquid crystal display device with less luminance unevenness over the entire screen can be realized.

Embodiment 3 FIG.
FIG. 9 schematically shows the structure of one pixel of the liquid crystal display device according to the third embodiment. FIG. 9A is a plan view, and FIG. 9B is A in FIG. 9A. FIG. 10 is a process flow of the array substrate. In the figure, 1 is a glass substrate, 2 is a scanning line, 3 is a signal line, 4 is a thin film transistor (TFT), 5 is a drive electrode, 6 is a counter electrode, 7 is a storage capacitor, 8 is a common wiring, and 9 is a gate insulating film. 10 is a protective film, 11 is a liquid crystal, 12 is a black matrix, 14 is a contact hole, 15 is a source electrode of the transistor, and 16 is a drain electrode of the transistor. Reference numeral 20 denotes an array substrate (consisting of a glass substrate 1, a signal line 3, a drive electrode 5, a counter electrode 6, etc.), 30 denotes a counter substrate serving as a display screen disposed facing the array substrate 20, and 40 Is a gap between the signal line 3 and the counter electrode 6, and 50 is an opening of the pixel.

  When the array substrate 20 was formed, the protective film 10 was formed of a transparent insulating film such as silicon nitride or silicon oxide, and the surface of the protective film 10 had a step. However, in Embodiment 3, the protective film 10 is formed using a material such as an acrylic-melamine system or an acrylic-epoxy system having a function of flattening the surface of the layer to be formed, so that FIG. 10), as shown in FIG. 10, the surface level difference of the protective film 10 is eliminated and the surface is flattened.

  In the IPS-type liquid crystal display device according to the third embodiment, the surface of the protective film 10 is flattened, so that the distance (gap) between the surface of the array substrate 20 and the counter substrate 30 is uniformly uniform over the entire display screen. This makes it possible to manufacture a liquid crystal display device with less luminance unevenness over the entire screen. In addition, the defect occurrence rate due to cracks or the like in the step portion of the protective film 10 is reduced, and the yield is improved. In addition, a high-quality liquid crystal display device can be realized with uniform rubbing treatment necessary for liquid crystal alignment and less alignment disorder.

  Similarly to the first embodiment, since the drive electrode 5 and the counter electrode 6 are provided in a layer closer to the liquid crystal than the layer in which the signal line 3 is formed, the liquid crystal can be driven efficiently. Since the interval between the counter electrodes 6 can be widened, there is an effect that the aperture ratio is also improved.

Embodiment 4 FIG.
FIG. 11 schematically shows the structure of one pixel of the IPS liquid crystal display device according to the fourth embodiment. FIG. 11 (a) is a plan view, and FIG. 11 (b) is FIG. 11 (a). It is sectional drawing in AA '. In the figure, 1 is a glass substrate, 2 is a scanning line, 3 is a signal line, 4 is a thin film transistor (TFT), 5 is a drive electrode, 6 is a counter electrode, 7 is a storage capacitor, 8 is a common wiring, and 9 is a gate insulating film. Reference numeral 10 denotes a protective film, 11 denotes a liquid crystal, 14 denotes a contact hole, 15 denotes a source electrode of the thin film transistor (TFT) 4, and 16 denotes a drain electrode of the thin film transistor (TFT). Reference numeral 20 denotes an array substrate (consisting of a glass substrate 1, a signal line 3, a drive electrode 5, a counter electrode 6 and the like), 30 denotes a counter substrate serving as a display screen disposed facing the array substrate 20, 60 Is a light-shielding film provided on the glass substrate 1.

  In the pixel structure of the liquid crystal display device according to the first to third embodiments, the fourth embodiment blocks light leaked from the gap 40 (see FIG. 18A) between the signal line 3 and the counter electrode 6. The light shielding film 60 is formed on the glass substrate 1. The structure of the liquid crystal display device according to the fourth embodiment will be described below with reference to FIGS. 11 (a) and 11 (b).

  In FIG. 11B, a light shielding film 60 is formed on the glass substrate 1. Although not shown in FIG. 11B, the scanning line 2 is also formed in the same layer as the light shielding film 60. The scanning line 2 also functions as a gate electrode of a thin film transistor (TFT) 4. A gate insulating film 9 is laminated on the scanning line 2 and the light shielding film 60. The signal line 3 is formed on the gate insulating film 9 at a position overlapping the light shielding film 60. A thin film transistor (TFT) 4 is also formed on the gate insulating film 9. The thin film transistor (TFT) 4 may be either a channel etch type TFT or a channel protective film type TFT. The source electrode 15 and the drain electrode 16 of the thin film transistor (TFT) 4 are also formed in the same layer as the signal line 3, and the protective film 10 is further laminated. Subsequently, a contact hole 14 is formed in the protective film 10, and the drive electrode 5 provided on the protective film 10 and the drain electrode of the thin film transistor (TFT) 4 provided on the gate insulating film 9 are connected via the contact hole 14. Connect.

  Similar to the drive electrode 5, the counter electrode 6 is also formed on the protective film 10. The counter electrode 6 is provided so as to overlap the light shielding film 60 through the drain electrode 16 and the protective film 10 to form a storage capacitor 7 that holds the potential of the drive electrode 5. The counter electrode 6 is connected to a common wiring 8 provided on the same layer. Broken lines are shown at both ends of the pixel in FIG. This broken line indicates the position of the light shielding film 60 provided on the glass substrate 1 shown in FIG. 11B in FIG. As shown by the broken line, the opposing electrodes 6 at both ends are formed so as to overlap the light shielding film 60, thereby covering the gap 40 (see FIG. 18A) between the signal line 3 and the opposing electrode 6. I understand.

  In the fourth embodiment, the drive electrode 5 and the counter electrode 6 are formed on the protective film 10, but the drive electrode 5 and the signal line 3 are simultaneously formed on the gate insulating film 9, and a protective film is formed using silicon nitride or the like. After the formation, the counter electrode 6 may be formed. In this case, the drive electrode 5 and the counter electrode 6 are formed in separate layers. In the fourth embodiment, since the light shielding film 60 is formed on the glass substrate 1, light leakage from the gap 40 (not shown) between the signal line 3 and the counter electrode 6 does not occur. The width of the matrix (BM) 12 can be reduced, or the black matrix 12 need not be shielded from light in the direction of the signal line 3. Therefore, the black matrix 12 can be omitted, and a large opening can be obtained.

  The liquid crystal display device is manufactured by stacking and combining the array substrate 20 and the counter substrate 30 with a color filter, enclosing the liquid crystal 11 between these substrates, and connecting a drive circuit. However, an overlay error may occur in the process of superimposing the array substrate 20 and the counter substrate 30, and the overlay error is ensured so that the black matrix 12 can reliably block light leaked from the gap 40 of the array substrate 20. In consideration of this, it was necessary to make a large light-shielding area (see FIG. 18A). Therefore, by providing the light shielding film 60 on the array substrate 20, it is possible to reliably shield the light transmission part such as the gap 40, and there is no need to consider the overlay error between the array substrate 20 and the counter substrate 30. It was. Therefore, the black matrix 12 can be gathered to the minimum necessary size, and the opening can be enlarged.

  Further, in the IPS liquid crystal display device according to the fourth embodiment, similarly to the IPS liquid crystal display device according to the first embodiment, the drive electrode 5 and the counter electrode 6 are provided in a layer close to the liquid crystal. Can be driven and the interval between the electrodes can be widened, so that the aperture ratio can be improved.

Embodiment 5. FIG.
FIG. 12 schematically shows the structure of one pixel of the IPS liquid crystal display device according to the fifth embodiment. FIG. 12 (a) is a plan view thereof, and FIG. 12 (b) is a diagram of FIG. 12 (a). It is sectional drawing in AA '. In the figure, 1 is a glass substrate, 2 is a scanning line, 3 is a signal line, 4 is a thin film transistor (TFT), 5 is a drive electrode, 6 is a counter electrode, 7 is a storage capacitor, 8 is a common wiring, 9 is a gate insulating film 10 is a protective film, 11 is a liquid crystal, 12 is a black matrix, 14 is a contact hole, 15 is a source electrode of the transistor, and 16 is a drain electrode of the transistor. Reference numeral 20 denotes an array substrate (comprised of a glass substrate 1, a signal line 3, a drive electrode 5, a counter electrode 6 and the like), and 30 denotes a counter substrate serving as a display screen disposed facing the array substrate 20. .

  In the fifth embodiment, similarly to the first embodiment, the drive electrode 5 and the counter electrode 6 are formed in an upper layer than the signal line 3, and the counter electrode 6 is formed so as to cover the signal line 3. 3 is configured to be less affected by the leakage electric field from 3 and to prevent leakage light from 40 between the signal line 3 and the counter electrode 6 (see FIG. 18A). . FIG. 13 shows a result of simulating a change in potential generated between the drive electrode 5 formed so as to cover the signal line 3 and the counter electrode 6 formed in the same layer as the drive electrode 5. FIG. FIG. 13 shows the calculated potential at the upper or lower portion of the window when a white window is displayed in a halftone with a relative transmittance of 50%.

  FIG. 21 showing the potential distribution in the array substrate 20 of the conventional IPS liquid crystal display device having the drive electrode 5 and the counter electrode 6 below the signal line 3 is compared with FIG. Since the electric field generated by the potential difference with the counter electrode 6 is shielded by the counter electrode 6 disposed at the upper part so as to cover the signal line 3, the region near the signal line 3 in the opening 50 and the signal line 3 It can be seen that the potential distribution in the remote region is almost symmetrical.

  As described above, in the array substrate 20 of the IPS liquid crystal display device according to the fifth embodiment, the drive electrode 5 and the counter electrode 6 are provided above the signal line 3, and the counter electrode 6 is provided so as to cover the signal line 3. As a result, the influence of the electric field generated between the signal line 3 and the counter electrode 6 on the electric field generated between the drive electrode 5 and the counter electrode 6 can be greatly reduced. The counter electrode 6 can be made closer to the signal line 3, and the total area of the opening 50 can be increased.

  Further, since the counter electrode 6 is formed so as to cover the signal line 3, the leakage light can be reliably shielded and the black matrix 12 can be eliminated. Therefore, since the area of the opening 50 can be increased, a high-brightness liquid crystal display device can be provided, and the process of providing the black matrix 12 can be reduced, so that productivity is improved and cost is reduced. Liquid crystal display devices can now be manufactured. Further, as in the first embodiment, since the drive electrode 5 and the counter electrode 6 are formed in a layer close to the liquid crystal, the liquid crystal can be driven efficiently, the distance between the electrodes can be increased, and the aperture ratio is also improved. The

Embodiment 6 FIG.
FIG. 14 schematically shows the structure of one pixel of the IPS liquid crystal display device according to the sixth embodiment. FIG. 14 (a) is a plan view, and FIG. 14 (b) is FIG. 14 (a). It is sectional drawing in AA. The pixel configuration of the IPS liquid crystal display device according to the sixth embodiment shown in FIG. 14 is basically the same as the pixel configuration of the IPS liquid crystal display device according to the fifth embodiment shown in FIG. Therefore, explanation is omitted. Although the case where the counter electrode 6 having a structure that completely covers the signal line 3 is provided in the fifth embodiment, the counter electrode 6 of the pixel of the IPS liquid crystal display device according to the sixth embodiment shown in FIG. Alternatively, the counter electrode 6 having a structure covering a part of the signal line 3 may be used.

  According to the sixth embodiment, since the counter electrode 6 is formed so as to cover a part of the signal line 3, the electric field generated by the potential difference between the signal line 3 and the counter electrode 6 is generated by the drive electrode 5 and the counter electrode 6. The influence on the electric field between the signal lines 3 and the counter electrode 6 can be reduced, and the leakage light that passes through the gap 40 between the signal line 3 and the counter electrode 6 can be blocked. The black matrix 12 can be eliminated, and a high-brightness liquid crystal display device with a wide opening can be realized. Further, by eliminating the black matrix 12, the process of providing the black matrix 12 can be reduced, so that the productivity is improved. It can also be seen that the area where the signal line 3 and the counter electrode 6 overlap is reduced, so that the occurrence of short-circuit defects between the signal line 3 and the counter electrode 6 is reduced. Furthermore, since the area where the signal line 3 and the counter electrode 6 overlap is reduced, the capacitance between the signal line 3 and the counter electrode 6 can be reduced, the wiring load is reduced, and driving is facilitated.

Embodiment 7 FIG.
FIG. 15 schematically shows the structure of one pixel of the IPS liquid crystal display device according to the seventh embodiment. FIG. 15 (a) is a plan view thereof, and FIG. 15 (b) is a diagram of FIG. 15 (a). It is sectional drawing in AA '. The configuration of the pixel of the IPS liquid crystal display device according to the seventh embodiment shown in FIG. 15 is the same as the configuration of the pixel of the IPS liquid crystal display device according to the fifth embodiment shown in FIG. Omitted. In the pixel structure of the liquid crystal display device according to the sixth embodiment, for example, as shown in FIG. 14, the seventh embodiment is formed by enlarging the counter electrode 6 over the scanning line 2, and using the counter electrode 6, The counter electrode 6 of another pixel adjacent to this pixel is connected.

  By using such a structure, the width of the counter electrode 6 is increased, the resistance of the counter electrode 6 is reduced, and the load is reduced, so that driving is facilitated. Further, even if the common wiring 8 is disconnected, the potential is supplied from the counter electrode 6 on the scanning line 2, so that there is no display defect. Therefore, the reliability of the product is improved. Note that the structure of the counter electrode 6 according to the seventh embodiment can be applied not only to the seventh embodiment but also to other embodiments, and it goes without saying that the same effect can be obtained.

Embodiment 8 FIG.
FIG. 16 schematically illustrates a cross-sectional structure of the storage capacitor portion in one pixel of the liquid crystal display device according to the eighth embodiment. In the figure, 17 is an electrode for increasing the storage capacity formed on the glass substrate 1, and 16 is a drain electrode of a thin film transistor (TFT). As shown in the figure, the liquid crystal display device according to the eighth embodiment is held. The capacitor portion is formed by laminating the electrode 17 for increasing the storage capacitor on the layer separate from the drain electrode 16 of the thin film transistor (TFT) via the gate insulating film 9 (for example, the layer of the scanning line 2). Yes. In this manner, by forming the electrode of the storage capacitor portion in a laminated structure, the area of the electrode for forming the storage capacitor can be reduced, and as a result, the opening 50 (not shown) of the pixel is formed. Can be wide.

Embodiment 9 FIG.
FIG. 17 is a diagram illustrating a process flow of the array substrate according to the ninth embodiment. In FIG. 17, 1 is a glass substrate, 2 is a scanning line, 3 is a signal line, 4 is a thin film transistor (TFT), 5 is a drive electrode, 6 is a counter electrode, 8 is a common wiring, 9 is a gate insulating film, and 10 is a protective film. 14 is a contact hole, 15 is a source electrode of the transistor, 16 is a drain electrode of the transistor, and 19 is a second protective film. The array substrate 20 includes a glass substrate 1, a signal line 3, a drive electrode 5, a counter electrode 6, and the like.

  In the ninth embodiment, the second protective film 19 is formed on the array substrate 20 shown in FIGS. Therefore, the structure of one pixel of the liquid crystal display device according to the ninth embodiment is the same as that of the first embodiment. A method for manufacturing the liquid crystal display device according to the ninth embodiment will be described below. The process flow of the array substrate in the ninth embodiment is the same as that in the first embodiment up to the step of forming the counter electrode 6. The ninth embodiment is characterized in that the second protective film 19 is formed on the upper layer of the counter electrode 6.

  By forming the second protective film 19 between the drive electrode 5 and the counter electrode 6, a short circuit between the drive electrode 5 and the counter electrode 6 due to foreign matter can be prevented, and the yield is improved. Further, since the level difference between the drive electrode 5 and the counter electrode 6 can be flattened, a high-quality liquid crystal display device can be realized in which the rubbing treatment necessary for the alignment of the liquid crystal is uniformly performed and the alignment is not disturbed.

1 is a cross-sectional view showing a structure of one pixel of an IPS liquid crystal display device according to a first exemplary embodiment; 1 is a plan view showing a structure of one pixel of an IPS liquid crystal display device according to a first exemplary embodiment; FIG. 2 is a plan view and a cross-sectional view showing a structure of one pixel of the IPS liquid crystal display device according to the first exemplary embodiment. FIG. 3 is a diagram showing a process flow of the array substrate of the IPS liquid crystal display device according to the first exemplary embodiment; FIG. 3 is a diagram showing a process flow of the array substrate of the IPS liquid crystal display device according to the first exemplary embodiment; FIG. 3 is a diagram showing a process flow of the array substrate of the IPS liquid crystal display device according to the first exemplary embodiment; FIG. 6 is a plan view and a cross-sectional view illustrating a structure of one pixel of an IPS liquid crystal display device according to a second embodiment. FIG. 6 is a diagram showing a process flow of an array substrate of an IPS liquid crystal display device according to a second exemplary embodiment; FIG. 6 is a plan view and a cross-sectional view showing a structure of one pixel of an IPS liquid crystal display device according to a third exemplary embodiment. FIG. 10 is a diagram showing a process flow of an array substrate of an IPS liquid crystal display device according to a third exemplary embodiment; FIG. 6 is a plan view and a cross-sectional view illustrating a structure of one pixel of an IPS liquid crystal display device according to a fourth embodiment. FIG. 6 is a plan view and a cross-sectional view showing a structure of one pixel of an IPS liquid crystal display device according to a fifth exemplary embodiment. It is a figure which shows electric potential distribution when a drive electrode and a counter electrode exist in a layer above a signal line. FIG. 10 is a plan view and a cross-sectional view showing a structure of one pixel of an IPS liquid crystal display device according to a sixth embodiment. FIG. 10 is a plan view and a cross-sectional view showing the structure of one pixel of an IPS liquid crystal display device according to a seventh embodiment. FIG. 10 is a cross-sectional view illustrating a structure of one pixel of an IPS liquid crystal display device according to an eighth embodiment; FIG. 10 is a diagram illustrating a process flow of an array substrate of an IPS liquid crystal display device according to a ninth embodiment; It is the top view and sectional drawing which show the structure of one pixel of the conventional IPS type | mold liquid crystal display device. It is a figure which shows the equivalent circuit of 1 pixel of the conventional IPS type | mold liquid crystal display device. It is a block diagram which shows the structure of the conventional IPS type | mold liquid crystal display device. It is a figure which shows potential distribution when a drive electrode and a counter electrode are in a lower layer from a signal line. It is a figure which shows crosstalk.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Glass substrate 2 Scan line 3 Signal line 4 Thin-film transistor (TFT) 5 Drive electrode 6 Counter electrode 7 Retention capacity 8 Common wiring 9 Gate insulating film 10 Protective film 11 Liquid crystal 12 Black matrix (BM)
13 Holding Capacitance 14 Contact Hole 15 Source Electrode 16 Drain Electrode
17 Electrode for increasing retention capacity 18 Through hole 19 Second protective film 20 Array substrate 21 Channel protective film 30 Counter substrate 40 Gap 50 Opening 60 Light shielding film

Claims (9)

A scanning line for transmitting a scanning signal, a signal line for transmitting a video signal, a plurality of pixel areas arranged in a matrix, and a plurality of pixel areas arranged in a matrix. An array substrate comprising: a thin film transistor connected to a line and the signal line, and switching a video signal based on a scanning signal; a drive electrode connected to the thin film transistor; and a counter electrode arranged to face the drive electrode When,
A counter substrate provided to face the array substrate;
In an in-plane switching type liquid crystal display device comprising a liquid crystal sealed between the array substrate and the counter substrate and driven by generating an electric field parallel to the drive electrode and the counter electrode.
The drive electrode and the counter electrode are formed in the same layer on a protective film formed in an upper layer than the scanning line and the signal line,
The counter electrode is formed by enlarging a projection surface on the substrate side of a portion close to the scanning line up to the scanning line so as to fill a gap with the scanning line,
In each of the pixel regions, the counter electrode is formed so as to surround the drive electrode, and the counter electrode of each pixel region adjacent to the pixel region in the scanning line direction and adjacent to the pixel region in the signal line direction. An in-plane switching type liquid crystal display device, wherein the counter electrode of each pixel region is connected to the counter electrode of the pixel region. The said counter electrode forms the projection surface to the board | substrate side of the site | part close | similar to the said signal line expanding to the said signal line so that the gap | interval with the said signal line may be filled. The in-plane switching type liquid crystal display device described. 2. The counter electrode according to claim 1, wherein a projection surface on the substrate side of a portion close to the scanning line and the signal line has a lattice shape covering the entire surface of the scanning line and the signal line. Item 3. The in-plane switching liquid crystal display device according to Item 2. 4. The counter electrode according to claim 1, wherein the counter electrode is formed by enlarging a projection surface on a substrate side of a portion close to the scanning line to the top of the thin film transistor. In-plane switching type liquid crystal display device. 5. The in-plane switching liquid crystal display device according to claim 1, wherein the drain electrode of the thin film transistor has an enlarged electrode portion that forms a storage capacitor. 6. The common wiring is formed in the same layer as the scanning line, and the signal line is formed in an upper layer than the common wiring and the scanning line. In-plane switching type liquid crystal display device. The in-plane switching liquid crystal display device according to claim 6, wherein in each of the pixel regions, the counter electrode is connected to the common line through a contact hole. The in-plane according to claim 1, further comprising a terminal portion, wherein the uppermost layer film of the terminal portion is formed in the same layer as the drive electrode and the counter electrode. Switching type liquid crystal display device. 9. The in-plane switching type liquid crystal display device according to claim 1, wherein the protective film has a flat shape made of a resin.

Images