JP2017211678A - Liquid crystal display device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To solve such a problem that when the diameter of a through hole to connect a pixel electrode and a source electrode is decreased, alignment layer material is less likely to flow into the through hole.SOLUTION: An interlayer insulating film 109 made of SiN is formed on a counter electrode, and a pixel electrode 110 having a slit 1101 is formed on the film. A through hole 111 connecting the pixel electrode 110 and a source electrode of a TFT has an upper large hole, a lower small hole, and an inner wall connecting the large hole and the small hole. The pixel electrode 110 covers the through hole 111 in a direction inside a pixel of the through hole 111 but does not cover a periphery of the large hole of the through hole in a direction outside the through hole 111. Thereby, an alignment layer is easily made to flow into the through hole, starting from a pixel electrode end.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a display device, and more particularly, to a liquid crystal display device in which a decrease in transmittance is small even on a high-definition screen and pixel defects are small.

  In a liquid crystal display device, a pixel substrate and pixels having thin film transistors (TFTs) etc. are formed in a matrix, and a TFT substrate is opposed to the TFT substrate, and a color filter is formed at a location corresponding to the pixel electrode of the TFT substrate A substrate is disposed, and liquid crystal is sandwiched between the TFT substrate and the counter substrate. An image is formed by controlling the light transmittance of the liquid crystal molecules for each pixel. The pixels are surrounded by scanning lines extending in the first direction and arranged in the second direction, and video signal lines extending in the second direction and arranged in the first direction. Area.

  Since liquid crystal display devices are flat and lightweight, they are used in various fields. Small liquid crystal display devices are widely used for mobile phones, DSCs (Digital Still Cameras), and the like. A viewing angle characteristic is a problem in a liquid crystal display device. The viewing angle characteristic is a phenomenon in which luminance changes or chromaticity changes when the screen is viewed from the front and when viewed from an oblique direction. The viewing angle characteristic is excellent in an IPS (In Plane Switching) system in which liquid crystal molecules are operated by a horizontal electric field.

  There are various types of IPS systems. For example, a common electrode is formed in a flat plane, and a pixel electrode having a slit is disposed on the common electrode, and a liquid crystal is generated by an electric field generated between the pixel electrode and the common electrode. Since the method of rotating molecules can increase the transmittance, it is currently mainstream. The common electrode and the interlayer insulating film are formed on an organic passivation film that also serves as a planarization film.

  On the other hand, in a liquid crystal display device, when the pixel size is reduced as a high-definition screen, the proportion of the diameter of the through hole connecting the pixel electrode and the TFT source electrode increases.

  In order to reduce the diameter of the through hole as the pixel becomes smaller and the pixel becomes smaller, the taper angle of the wall portion of the through hole (hereinafter sometimes referred to as the taper angle of the through hole) must be increased. On the other hand, an alignment film is used for initial alignment of the liquid crystal, and this alignment film material is initially applied (before application) in a liquid state by flexographic printing or inkjet.

  When the taper angle of the through hole is increased, when the alignment film material is applied, a phenomenon occurs in which the alignment film material does not enter the through hole due to surface tension. Then, since the liquid crystal state is different in the portion where the alignment film is formed thick, light leaks from this portion, resulting in display unevenness.

  “Patent Document 1” describes a configuration in which the alignment film easily flows into the through hole by changing the height around the large hole on the upper side of the through hole. The method of changing the height around the large hole on the upper side of the through hole in “Patent Document 1” is a configuration in which a step provided in the lower layer film is reflected around the large hole on the upper side of the through hole.

  “Patent Document 2” solves the problem that the photoresist for forming the pixel electrode pattern does not enter the concave portion of the through hole, and the pixel electrode is etched in the through hole, so that the pixel electrode cannot be conductive. Therefore, a configuration is described in which a step is provided around the large hole on the upper side of the through hole so that the photoresist can easily enter the through hole. Moreover, it is described that the same problem arises also about application | coating of alignment film. The method of changing the height around the large hole on the upper side of the through hole in “Patent Document 2” is also configured to reflect the step provided on the lower layer film on the periphery of the large hole on the upper side of the through hole.

  “Patent Document 3” describes a configuration in which an inner wall of a through hole is also used as a region for image formation by using a photo-alignment process on an alignment film in an IPS liquid crystal display device. For this purpose, “Patent Document 3” describes a configuration in which a slit of a pixel electrode is formed also on the inner wall of a through hole.

JP 2007-322563 A JP 2008-275879 A JP2013-140386A

  Recently, high-definition screens such as VGA (Video Graphics Array, 640 × 480 dots) are also required for small liquid crystal display devices. Here, the dot is a set of three pixels of a red pixel, a green pixel, and a blue pixel, and thus the number of pixels is 1920 × 480. In order to enable VGA on a 3-inch screen, the minor axis of the pixel is very small, such as 32 μm.

  In order to maintain a predetermined transmittance even when the pixel becomes small, it is necessary to arrange TFTs, through holes, etc. in a small area and to make the ratio of the pixel electrode area as large as possible. When trying to reduce the area occupied by the through-hole, the taper angle of the through-hole is increased, the alignment film material is less likely to flow into the through-hole, and sesame pixel defects are generated.

  Since the configuration of Patent Document 1 or 2 is provided by providing a step in the lower layer film and reflecting this step around the large hole on the upper side of the through hole, an attempt is made to provide a height difference around the upper part of the through hole. Then, a so-called organic passivation film cannot be used. This is because the organic passivation film is formed as thick as 2 to 4 μm, so that the surface becomes flat and it is difficult to form a height difference around the through hole.

  On the other hand, depending on the type of the liquid crystal display device, it is necessary to use an organic passivation film in order to make the layer thickness of the liquid crystal layer constant. In addition, since the organic passivation film is formed with a thickness of 2 to 4 μm, if a through hole is formed in the organic passivation film, the problem that the area occupied by the through hole becomes more serious.

  FIG. 14 is a cross-sectional view showing the above problem in an IPS liquid crystal display device. In FIG. 14, a gate electrode 101 is formed on a TFT substrate 100, and a gate insulating film 102 is formed covering the gate electrode 101. A semiconductor layer 103 is formed on the gate insulating film 102 at a location corresponding to the gate electrode 101. A drain electrode 104 and a source electrode 105 are stacked on the semiconductor layer 103. An inorganic passivation film 106 is formed to cover the semiconductor layer 103, the drain electrode 104, the source electrode 105, and the like, and protects the TFT (Thin Film Transistor). On the inorganic passivation film 106, an organic passivation film 107 serving also as a planarization film is formed. The organic passivation film 107 is formed as thick as 2 to 4 μm.

  A counter electrode 108 to which a common voltage is applied is formed on the organic passivation film 107. An interlayer insulating film 109 made of SiN is formed so as to cover the counter electrode (also referred to as a common electrode) 108. A pixel electrode 110 having a slit (not shown) is formed on the interlayer insulating film 109. The pixel electrode 110 is connected to the source electrode 105 extending from the TFT through a through hole 111 formed in the interlayer insulating film 109, the organic passivation film 107 and the inorganic passivation film 106.

  An alignment film 120 is applied on the pixel electrode 110 by flexographic printing, an inkjet method, or the like. However, when the diameter of the through hole 111 is reduced, the taper angle of the through hole 111 is increased, and a phenomenon occurs in which the alignment film material that is initially liquid does not enter the through hole. Then, as shown in FIG. 14, a phenomenon occurs in which the alignment film 120 is formed thick around the through hole 111.

  As described above, when the film thickness unevenness occurs in the alignment film 120, the liquid crystal state differs from that in other regions, and thus display unevenness occurs. Since the alignment film material does not enter the through hole 111, the phenomenon that the thickness of the alignment film 120 increases around the through hole 111 does not occur only in one pixel 10, but in FIG. As shown in the hatched portion, it often occurs in a plurality of pixels 10. As a result, display unevenness is more noticeable.

  In FIG. 15, pixels 10 having pixel electrodes 110 are formed in a matrix. The pixel electrode 110 has a slit 1101 and is connected to a source electrode of a TFT (not shown) through a through hole 111. The through hole 111 penetrates the interlayer insulating film, the organic passivation film, and the inorganic passivation film. The pixel electrode 110 covers the entire through hole 111.

  FIG. 16 is a perspective view showing a part of a pixel. In FIG. 16, a pixel electrode 110 having a slit 1101 is formed on an interlayer insulating film 109 made of SiN by ITO (Indium Tin Oxide). The pixel electrode 110 covers the entire through hole 111. The alignment film material is applied on the pixel electrode 110. However, when the diameter of the through hole 111 is reduced, the alignment film material does not enter the through hole 111, and the alignment film 120 is placed around the through hole as shown in FIG. The phenomenon that it is formed thick occurs.

  An object of the present invention is to make the alignment film material easily flow into the through-hole even when the pixel size is reduced and the through-hole diameter is reduced with a high-definition screen. It is to realize a liquid crystal display device having a high-quality screen by preventing unevenness.

  The present invention overcomes the above problems, and specific means are as follows.

  (1) A common electrode is formed on the organic passivation film, an interlayer insulating film is formed to cover the common electrode, and a pixel electrode having a slit whose end is closed is formed on the interlayer insulating film. A TFT substrate having a pixel in which the TFT source electrode and the pixel electrode are electrically connected through a through hole formed in the organic passivation film and the interlayer insulating film, and a color filter in a portion corresponding to the pixel A liquid crystal display device having a substrate, wherein liquid crystal is sandwiched between the TFT substrate and the counter substrate, wherein the through hole has a large hole on the upper side and a small hole on the lower side to which the source electrode is connected; An inner wall connecting the large hole and the small hole, and the pixel electrode covers the through hole in an inner direction of the pixel of the through hole, The direction, the liquid crystal display device, characterized in that does not cover the large hole around the through hole.

  (2) A common electrode is formed on the organic passivation film, an interlayer insulating film is formed to cover the common electrode, and a pixel electrode having a slit with a closed end is formed on the interlayer insulating film. A TFT substrate having a pixel in which the TFT source electrode and the pixel electrode are electrically connected through a through hole formed in the organic passivation film and the interlayer insulating film, and a color filter in a portion corresponding to the pixel A liquid crystal display device having a substrate, wherein liquid crystal is sandwiched between the TFT substrate and the counter substrate, wherein the through hole has a large hole on the upper side and a small hole on the lower side to which the source electrode is connected; The large hole has an inner wall connecting the small hole, the planar shape of the large hole has a long diameter and a short diameter, the pixel is rectangular, and the long diameter of the large hole of the through hole is A major axis direction of the serial pixel, the slit is a liquid crystal display device, characterized in that also extends to the inner wall of the through hole.

  (3) A common electrode is formed on the organic passivation film, an interlayer insulating film is formed to cover the common electrode, and a pixel electrode having a slit with a closed end is formed on the interlayer insulating film. A TFT substrate having a pixel in which the TFT source electrode and the pixel electrode are electrically connected through a through hole formed in the organic passivation film and the interlayer insulating film, and a color filter in a portion corresponding to the pixel A liquid crystal display device having a substrate, wherein liquid crystal is sandwiched between the TFT substrate and the counter substrate, wherein the through hole has a large hole on the upper side and a small hole on the lower side to which the source electrode is connected; The large hole has an inner wall connecting the small hole, the planar shape of the large hole has a long diameter and a short diameter, and the pixel electrode includes the main pixel electrode having the slit and the mesa. A pixel electrode and a sub-pixel electrode arranged with a gap, the pixel is rectangular, the major axis of the large hole of the through hole is the minor axis direction of the pixel, and in the gap part, A liquid crystal display device, wherein a periphery of the large hole of the through hole is not covered with a pixel electrode.

(4) A common electrode is formed on the organic passivation film, an interlayer insulating film is formed to cover the common electrode, and a pixel electrode having a slit with a closed end is formed on the interlayer insulating film. A TFT substrate having a pixel having a structure in which a source electrode of the TFT and a pixel electrode are electrically connected through a through hole formed in the organic passivation film and the interlayer insulating film;
A liquid crystal display device having a counter substrate having a color filter in a portion corresponding to the pixel, and a liquid crystal sandwiched between the TFT substrate and the counter substrate, wherein the through-hole is an upper hole; A liquid crystal display device comprising: a small hole which is a lower side for connecting the source electrode; and an inner wall connecting the large hole and the small hole, wherein the small hole of the through hole is eccentric with respect to the large hole.

(5) A common electrode is formed on the organic passivation film, an interlayer insulating film is formed to cover the common electrode, and a pixel electrode having a slit with a closed end is formed on the interlayer insulating film. A TFT substrate having a pixel in which the TFT source electrode and the pixel electrode are electrically connected through a through hole formed in the organic passivation film and the interlayer insulating film, and a color filter in a portion corresponding to the pixel A liquid crystal display device having a substrate, wherein liquid crystal is sandwiched between the TFT substrate and the counter substrate,
An interval between the TFT substrate and the counter substrate is defined by a columnar spacer formed on the counter substrate, and the through hole includes a large hole on the upper side, a small hole on the lower side connecting the source electrode, the large hole, and the small hole. The small hole of the through hole is eccentric to the side of the columnar spacer closest to the through hole with respect to the large hole.

  According to the present invention, a liquid crystal display device having a high-definition screen, a small pixel area, and an organic passivation film on a TFT substrate, the liquid crystal alignment film material can be stabilized even when the through-hole diameter is small. Can be formed in the through hole. Accordingly, it is possible to prevent display unevenness due to the absence of the alignment film in the through hole or due to uneven film thickness of the alignment film around the through hole.

4 is a plan view of a pixel of the liquid crystal display device according to Embodiment 1. FIG. 4 is a perspective view of a pixel of the liquid crystal display device according to Embodiment 1. FIG. 4 is a cross-sectional view of a through hole in a pixel of a liquid crystal display device according to Embodiment 1. FIG. 6 is a plan view of a pixel of a liquid crystal display device according to Embodiment 2. FIG. 6 is a plan view of a pixel of a liquid crystal display device according to Example 3. FIG. FIG. 7 is a perspective view and a cross-sectional view of a through hole according to a fourth embodiment. FIG. 14 is a plan view of a pixel and a cross-sectional view of a through hole according to another embodiment of Example 4. 14 is a plan view of a pixel according to still another embodiment of Example 4. FIG. 14 is a plan view of a pixel according to another embodiment of Example 4. FIG. 14 is a plan view of a pixel according to another embodiment of Example 4. FIG. 14 is a plan view of a pixel according to another embodiment of Example 4. FIG. 14 is a plan view of a pixel according to another embodiment of Example 4. FIG. It is a figure which defines the cross-sectional shape of a through hole. It is sectional drawing of the through hole which shows the trouble of a prior art example. It is a top view of the display area which shows the problem of a prior art example. It is a perspective view shown with the pixel structure of a prior art example.

  The contents of the present invention will be described in detail below using examples.

  FIG. 1 is a plan view showing a pixel 10 according to the present invention. In FIG. 1, a pixel electrode 110 having a slit 1101 is formed on an interlayer insulating film 109 made of SiN. A counter electrode (not shown) is formed under the interlayer insulating film 109. When a signal voltage is applied to the pixel electrode 110, the lines of electric force are directed to the lower counter electrode through the slit 1101 of the pixel electrode 110. As a result, a lateral electric field is formed in the liquid crystal layer, and the liquid crystal molecules are rotated by the lateral electric field. Thus, an image is formed by controlling the transmittance of the liquid crystal for each pixel 10.

  The pixel electrode 110 is connected to the source electrode of the TFT through the through hole 111. The feature of the present invention is that the pixel electrode 110 does not cover the entire through hole 111, and the pixel electrode is located near the through hole 111 in the outer direction of the pixel. 110 does not exist. FIG. 2 shows this state using a perspective view. In FIG. 2, the pixel electrode 110 having the slit 1101 is formed on the interlayer insulating film 109, but the pixel electrode 110 is formed only in the inner direction of the pixel 10 on the upper side of the through hole 111, It is not formed in the direction.

  As a result, a step is formed around the upper side of the through hole 111 by the thickness of the ITO. If a step is formed on the upper side of the through hole 111, the alignment film material that is a liquid is likely to flow into the through hole 111 starting from this step. Further, the alignment film material is more easily spread and spread on SiN constituting the interlayer insulating film 109 than on ITO constituting the pixel electrode. Therefore, the alignment film material easily flows into the through hole 111 from the side where the ITO film is not present, that is, from the outside of the pixel 10. Due to these two phenomena, the alignment film material easily flows into the through hole 111 in the present invention.

  FIG. 3 is a cross-sectional view of the pixel including the TFT and the through hole 111 in this embodiment. In FIG. 3, the configuration until the interlayer insulating film 109 is formed is the same as that in FIG. A feature of the present invention is that the pixel electrode 110 formed on the interlayer insulating film 109 is formed only on one side of the through hole 111, and the pixel electrode 110 is not formed on the opposite side of the through hole 111. Is a point.

  In FIG. 3, the left side of the figure in which the TFT is formed corresponds to the outside direction of the pixel, and the right side of the figure corresponds to the inside direction of the pixel. In FIG. 3, the pixel electrode 110 is formed in the through hole 111 in the inner direction of the pixel and is connected to the source electrode 105. The pixel electrode 110 is not formed near the inner wall and the upper side of the through hole 111 in the outer direction of the pixel in FIG. 3, and the interlayer insulating film 109 is exposed. Since the alignment film material is more easily spread on the SiN constituting the interlayer insulating film 109 than on the ITO constituting the pixel electrode 110, the alignment film material flows into the through hole 111 from the outside of the pixel. In other words, unevenness in the thickness of the alignment film can be suppressed.

  FIG. 4 is a plan view of a pixel showing a second embodiment of the present invention. The through hole 111 has a large hole 1112 and a small hole 1111. The feature of FIG. 4 is that the large hole 1112 of the through hole 111 is an ellipse having a major axis in the longitudinal direction of the pixel. Therefore, the cross-sectional shape of the through hole 111 is such that the taper angle of the cross section in the major axis direction of the pixel is smaller than the taper angle of the cross section in the minor axis direction of the pixel.

  Further, the feature of FIG. 4 is that the slit 1101 of the pixel electrode 110 extends to the inner wall of the through hole 111. Therefore, a step due to the presence of the slit 1101 of the pixel electrode 110 is formed around the upper side of the through hole 111. With this step as a starting point, the alignment film material easily flows into the through hole.

  Furthermore, the taper angle of the through hole 111 on the side where the slit 1101 of the pixel electrode 110 is formed is small. The smaller the taper angle, the easier the alignment film material flows into the through hole 111. That is, in the present embodiment, the upper side of the through hole 111, that is, the large hole 1112 is elliptical, and the slit 1101 extends to the inner wall of the through hole 111. The film material is easy to flow into the through hole 111. Thereby, display unevenness due to uneven film thickness of the alignment film can be prevented.

  In the configuration of the present embodiment, the shape of the large hole 1112 of the through hole 111 is not limited to an ellipse, and the same effect can be obtained by making the major axis a rectangle whose major axis is the major axis direction of the pixel. In other words, if the large hole 1112 of the through hole 111 has a major axis and a minor axis, and the major axis is the major axis direction of the pixel, the same effect can be obtained.

  In this embodiment, the slit 1101 of the pixel electrode 110 is formed up to the inner wall of the through hole 111. In this case, by using so-called photo-alignment, the alignment process can be performed on the alignment film formed in the through hole 111. The photo-alignment is, for example, an alignment treatment that imparts uniaxial anisotropy to the alignment film by irradiating the alignment film with polarized ultraviolet rays. Therefore, since the through hole 111 can also be used as an image forming region, the transmittance of the pixel can be improved.

  FIG. 5 is a plan view showing a third embodiment of the present invention. The feature of this embodiment is that the through-hole 111 is an ellipse having a major axis in the minor axis direction of the pixel, and the pixel electrode 110 has a main pixel electrode having a slit 1101 and a sub-pixel electrode formed in the outer direction of the pixel. It is a point that is separated. A gap 112 exists between the main pixel electrode and the sub pixel electrode.

  On the long diameter side of the large hole 1112 of the through hole 111, the taper angle of the inner wall of the through hole 111 is small. In addition, on the long diameter side of the large hole 1112 of the through hole 111, ITO forming the pixel electrode 110 does not exist, and SiN forming the interlayer insulating film 109 is exposed. Further, in the gap portion 112 where no ITO is present, a step due to ITO is formed.

  That is, in this embodiment, the taper angle of the through hole 111 is small, the SiN constituting the interlayer insulating film 109 is exposed, and a step due to ITO is formed near the major axis of the large hole 1112 of the through hole 111. Therefore, the alignment film material easily flows into the through hole 111 for three reasons. Therefore, the unevenness of the screen due to the unevenness of the film thickness of the alignment film material around the through hole can be prevented.

  In the configuration of the present embodiment, the shape of the large hole 1112 of the through-hole 111 is not limited to an ellipse, and the same effect can be obtained by making the major axis a rectangle with the minor axis direction of the pixel. In more general terms, the large hole 1112 of the through hole 111 in this embodiment has a major axis and a minor axis in the plan view, and the major axis 1112 of the major hole 1112 of the through hole 111 coincides with the minor axis direction of the pixel.

  In this embodiment, the gap 112 in FIG. 5 can also be used as a slit for image formation. Thereby, the transmittance of the pixel can be improved.

  FIG. 6 is a diagram showing a fourth embodiment of the present invention. In the present embodiment, the taper angle of the inner wall of the through hole is reduced in one cross section of the through hole 111 by shifting the center of the large hole 1112 that is the upper base in the through hole 111 and the center of the small hole 1111 that is the lower base. Is.

  FIG. 6A is a perspective view of the through hole 111 showing the characteristics of the present embodiment. In FIG. 6A, the centers of the large hole 1112 and the small hole 1111 of the through hole 111 are eccentric by d. As a result, the taper angle on the left side of the through hole in FIG. 6A is smaller than the taper angle on the right side of the through hole. The alignment film material flows into the through hole more easily when the taper angle of the through hole 111 is smaller. Therefore, the alignment film material flows into the through hole 111 from the left side of FIG.

  FIG. 6B is a cross-sectional view of the through hole portion according to the present embodiment. In FIG. 6B, since the center of the small hole 1111 of the through hole 111 is eccentric to the right with respect to the center of the large hole 1112, the taper angle α on the left side of the through hole 111 is more than the taper angle β on the right side. It is getting smaller. Therefore, the alignment film material easily flows into the through hole 111 from the left side in FIG.

  Thus, by forming a portion where the alignment film material easily flows around the through hole 111, the phenomenon that the alignment film material does not flow into the through hole 111 can be prevented.

  Since the organic passivation film 107 is as thick as 2 to 4 μm, the shape of the through hole 111 is dominated by the shape of the through hole formed in the organic passivation film 107. In order to form the through hole 111 in which the large hole 1112 and the small hole 1111 are eccentric as shown in FIG. 6A or 6B, the large hole and the small hole are eccentric when the through hole is formed in the organic passivation film 107. You can do it.

  In order to decenter the center of the large hole and small hole of the through hole formed in the organic passivation film 107, when exposing the organic passivation film 107, the side where the taper angle of the through hole is desired to be reduced is exposed using half exposure. Can be formed. That is, if the organic passivation film 107 is a positive photosensitive resin, the portion irradiated with light is dissolved in the developer. Therefore, by controlling the exposure amount on the side where the taper angle is reduced in the through hole by half exposure, the amount dissolved in the developer of the photosensitive resin can be controlled in the depth direction.

  FIG. 7 shows an example in which the eccentric directions of the large hole 1112 and the small hole 1111 in the through hole 111 are defined. FIG. 7A is a plan view. In FIG. 7A, the pixel electrode 110 is formed on one side of the through hole 111, that is, the inner side of the pixel, and the pixel electrode 110 is not formed on the other side, that is, the outer side of the pixel. In FIG. 7A, the center of the small hole 1111 of the through hole 111 is eccentric to the pixel electrode 110 side, in other words, the inner direction of the pixel with respect to the center of the large hole 1112. As a result, the taper angle of the through hole 111 is smaller in the outer direction of the pixel than in the inner direction of the pixel. Therefore, the alignment film material easily flows into the through hole 111 from the outside direction of the pixel.

  FIG.7 (b) is AA sectional drawing of Fig.7 (a). In FIG. 7B, the laminated structure up to the interlayer insulating film 109 is the same as described in FIG. In the through hole 111 of FIG. 7B, the taper angle α on the left side of the drawing, that is, the outer side of the pixel is smaller than the taper angle β on the right side of the drawing, that is, the inner side of the pixel. The pixel electrode 110 extends to the inner wall and bottom of the through hole 111 inside the pixel in the through hole 111. However, the pixel electrode 110 does not exist in the outer direction of the pixel in the through hole 111. That is, as described with reference to FIG. 6A, the taper angle α of the through hole 111 is small in the outer direction of the pixel, and the interlayer insulating film 109 formed of SiN is exposed. The alignment film material can easily flow from the outside direction.

  In the liquid crystal display device, the liquid crystal layer is sandwiched between the TFT substrate 100 and the counter substrate. In order to maintain the distance between the TFT substrate 100 and the counter substrate at a predetermined value, for example, the counter substrate side Columnar spacers 150 are formed on the substrate. If the columnar spacer 150 is present in the portion where the through hole 111 is formed, the distance between the TFT substrate 100 and the counter substrate cannot be controlled.

  Therefore, in design, the columnar spacers 150 formed on the counter substrate are arranged so as to avoid the positions of the through holes 111 formed on the TFT substrate 100. However, when a pressing force is applied to the counter substrate, the tip of the columnar spacer 150 may move, and the columnar spacer 150 may fall into the through hole 111. In order to eliminate such a possibility as much as possible, it is desirable to maintain a predetermined distance between the position of the columnar spacer 150 and the position of the through hole 111.

  In the through hole 111 in which the centers of the large hole 1112 and the small hole 1111 are decentered, the small hole 1111 of the through hole 111 must be in contact with the pixel electrode 110 without fail. FIG. 8 shows a configuration in which the space s between the columnar spacer 150 and the large hole 1112 of the through hole 111 is made as large as possible when the position of the small hole 1111 is used as a reference. That is, the center of the large hole 1112 of the through hole 111 is eccentric in the inner direction of the pixel as compared with the center of the small hole 1111.

  In other words, it can be said that the center of the small hole 1111 of the through hole 111 is decentered toward the columnar spacer 150 with respect to the center of the large hole 1112. With such a configuration, the space s between the large hole 1112 of the through hole 111 and the columnar spacer 150 can be increased, so that the probability that the columnar spacer 150 falls into the through hole 111 can be reduced. In addition, since a region with a small taper angle can be formed in the through hole 111, the flow of the alignment film material can be facilitated and the occurrence of display unevenness can be suppressed.

  FIG. 9 is a plan view showing a case where the columnar spacer 150 is formed at another position. Also in FIG. 9, the center of the small hole 1111 of the through hole 111 is eccentric in the direction in which the columnar spacer 150 exists with respect to the center of the large hole 1112. Also in FIG. 9, since the space s between the large hole 1112 of the through hole 111 and the columnar spacer 150 can be increased, the probability that the columnar spacer 150 falls into the through hole 111 can be reduced. In addition, since a region with a small taper angle can be formed in the through hole 111, the flow of the alignment film material can be facilitated and the occurrence of display unevenness can be suppressed.

  A large number of columnar spacers are formed in the display region. The columnar spacer 150 in FIGS. 8 and 9 refers to the columnar spacer 150 closest to the target through hole 111. To summarize the contents shown in FIGS. 8 and 9, it can be said that the small hole 1111 of the through hole 111 is eccentric to the columnar spacer 150 side with respect to the large hole 1112.

  6 to 9, the large hole 1112 and the small hole 1111 of the through hole 111 are described as being circular. However, the shape of the large hole 1112 or the small hole 1112 of the through hole 111 is not limited to a circle, and may be a rectangular shape. Hexagon shape may be sufficient.

  FIG. 10 is a plan view of the pixel portion showing an example in which the large hole 1112 is an ellipse and the small hole 1111 is a circle in the through hole 111. In FIG. 10, the center of the small hole 1111 of the through hole 111 is decentered in the pixel inner direction from the center of the large hole 1112 which is an ellipse. With this configuration, the taper angle of the through hole 111 can be further reduced in the outer direction of the pixel of the through hole 111. Accordingly, the shape of the through hole shown in FIG. 10 can further facilitate the flow of the alignment film material into the through hole than in the case of the through hole shown in FIG.

  FIG. 11 shows an example in which the planar shape of the large hole 1112 of the through hole 111 is not an ellipse but a rectangle. At this time, the small hole 1111 of the through hole 111 is a square. In the example of FIG. 11 as well, the center of the small hole 1112 of the through hole 111 is eccentric to the inner side of the pixel from the center of the large hole 1111. This example can also facilitate the flow of the alignment film material into the through hole 111, as described with reference to FIG.

  Note that the shape of the through hole 111 is not limited to the shape of FIG. 10 or FIG. 11, and other shapes can be similarly applied. That is, in the planar shape of the through hole 111 formed in the rectangular pixel, the large hole 1112 of the through hole 111 has a major axis and a minor axis that coincide with the major axis direction of the pixel, and the center of the small hole 1111 of the through hole 111 is If the configuration is decentered inward of the pixel from the center of the large hole 1112 of the through hole 111, the same effect as in FIG. 10 or FIG. 11 can be obtained.

  FIG. 12 shows an example in which the planar shape of the large hole 1112 of the through hole 111 is an ellipse in consideration of the position of the columnar spacer 150. In the through hole 111 of FIG. 12, the center of the small hole 1111 is eccentric to the columnar spacer 150 side from the center of the elliptical large hole 1112. With this configuration, the taper angle of the inner wall opposite to the columnar spacer 150 in the through hole 111 can be reduced, so that the alignment film material can be easily flowed. In addition, since the interval s between the columnar spacer 150 and the large hole 1112 of the through hole 111 can be increased with the configuration of FIG. 12, the probability that the columnar spacer 150 falls into the through hole 111 can be reduced.

  In the configuration shown in FIG. 12, the large hole 1112 of the through hole 111 is made into an ellipse, so that the orientation film easily flows into the through hole 111 and the probability that the columnar spacer 150 falls into the through hole 111 is reduced. This effect can also be improved over the configuration shown in FIG.

  In FIG. 12, the shape of the large hole 1112 of the through hole 111 is an ellipse. However, the shape is not limited to this, and the shape of the large hole 1112 may be a rectangle or another shape. That is, in the planar shape of the through hole 111, the large hole 1112 of the through hole 111 has a long diameter and a short diameter, and the center of the small hole 1111 of the through hole 111 is closer to the columnar spacer 150 side than the center of the large hole 1112 of the through hole 111. The configuration is eccentric. The major axis of the large hole 1112 is the direction of a line connecting the center of the large hole and the columnar spacer. With such a configuration, the same effect as in FIG. 12 can be obtained. The columnar spacer 150 in this case also refers to the columnar spacer 150 closest to the target through-hole 111.

  FIG. 13 shows a cross-sectional shape of the through hole formed in the organic passivation film 107 in the through hole 111. Since the organic passivation film 107 is as thick as 2 to 4 μm, it can be considered that the cross-sectional shape of the through hole 111 is governed by the cross-sectional shape of the through hole of the organic passivation film 107. Therefore, the depth of the through hole 111, the taper angle of the through hole 111, and the like may be defined by the depth of the through hole formed in the organic passivation film 107, the taper angle, and the like.

  In FIG. 13, the depth of the through hole of the organic passivation film 107 is D. In this case, the diameter of the large hole of the through hole is measured with reference to a position x where a line connecting the upper surface of the organic passivation film and a cross section of the through hole of the organic passivation film are in contact. Further, the diameter of the small hole of the through hole is measured based on the portion y where the organic passivation film is cut.

  Further, the taper angle α of the through hole is an angle α formed by a line tangent to the inner wall of the through hole at a position D / 3 from the upper surface of the organic passivation film 107 to a line connecting the upper surface of the through hole. That is, it can be said that the smaller the angle α, the easier the alignment film material flows into the through hole.

  In this specification, an interlayer insulating film is provided over the counter electrode and a pixel electrode is provided over the interlayer insulating film. However, a structure in which the positional relationship between the pixel electrode and the counter electrode is reversed may be employed. In this case, the counter electrode may be connected to another electrode or wiring through a through hole. Even in such a structure, the present invention can be applied to the counter electrode in order to facilitate the flow of the alignment film into the through hole. In this specification, a bottom-gate TFT in which a gate insulating film is provided over a gate electrode and a semiconductor layer is provided over the gate insulating film is disclosed, but the arrangement of the gate electrode and the semiconductor layer is reversed. A TFT having a top gate structure may be used. In addition, although it is a problem of the through hole formed in the organic passivation film, there is a possibility that the same problem may occur when the taper angle becomes steep even in the case of an inorganic insulating film. It can be applied to through holes in inorganic insulating films. Further, in the configuration of FIG. 3, the interlayer insulating film 109 remains in the place where the ITO is removed, but the interlayer insulating film in the through hole taper portion and / or the peripheral portion of the through hole is removed. Such a structure may be used.

  DESCRIPTION OF SYMBOLS 10 ... Pixel, 100 ... TFT substrate, 101 ... Gate electrode, 102 ... Gate insulating film, 103 ... Semiconductor layer, 104 ... Drain electrode, 105 ... Source electrode, 106 ... Inorganic passivation film, 107 ... Organic passivation film, 108 ... Opposite Electrode (common electrode), 109 ... interlayer insulating film, 110 ... pixel electrode, 111 ... through hole, 112 ... gap, 120 ... alignment film, 150 ... columnar spacer, 1101 ... slit, 1111 ... through hole small hole, 1112 ... through hole Large hole

Claims (8)

An organic film; a common electrode formed on the organic film; an interlayer insulating film formed to cover the common electrode; a pixel electrode having a slit formed on the interlayer insulating film; and the organic film And a TFT substrate having a through hole formed in the interlayer insulating film, and a TFT electrically connected to the pixel electrode through the through hole,
A counter substrate facing the TFT substrate;
A liquid crystal display device comprising: a liquid crystal sandwiched between the TFT substrate and the counter substrate;
The through hole has an upper side located on the liquid crystal side, and an inner wall formed from the upper side toward the TFT substrate side,
The upper side has a major axis and a minor axis in plan view,
The liquid crystal display device, wherein the slit extends to the inner wall. A pixel having the pixel electrode and the TFT;
The liquid crystal display device according to claim 1, wherein the major axis is a longitudinal direction of the pixel.   The through hole further has a lower side, the lower side is present on the TFT substrate side with respect to the upper side, and the lower side has a portion that is decentered in the center direction of the pixel with respect to the upper side. The liquid crystal display device according to claim 1 or 2.   4. The liquid crystal display device according to claim 1, wherein a taper angle of the through hole in the major axis direction is smaller than a taper angle of the through hole in the minor axis direction. 5. The TFT and the pixel electrode are connected and connected through the through hole,
5. The liquid crystal display device according to claim 1, wherein the slit does not extend to a portion where the TFT and the pixel electrode are connected. 6. A TFT substrate having an organic film, a through hole formed in the organic film, a first electrode formed on the organic film, and an alignment film formed to cover the first electrode;
A counter substrate facing the TFT substrate;
A liquid crystal display device comprising: a liquid crystal sandwiched between the TFT substrate and the counter substrate;
The through hole has an upper side located on the liquid crystal side, and an inner wall formed from the upper side toward the TFT substrate side,
The upper side has a major axis and a minor axis in plan view,
The first electrode has a slit and is formed in the through hole,
The slit extends to the inner wall;
The liquid crystal display device, wherein the alignment film is a photo-alignment film. An interval between the TFT substrate and the counter substrate is defined by a spacer,
The through-hole further has a lower side, the lower side exists on the TFT substrate side with respect to the upper side, and the lower side has a portion that is eccentric to the spacer side with respect to the upper side. The liquid crystal display device according to claim 1, wherein the liquid crystal display device is a liquid crystal display device.   The liquid crystal display device according to claim 7, wherein a direction of the major axis of the through hole is a direction connecting the spacer and a center of the upper side of the through hole.

Images