JP2006154080A - Liquid crystal display - Google Patents

Abstract

In a liquid crystal display device having a wide viewing angle, the aperture ratio of a pixel is not lowered even if an auxiliary capacitor is formed.
An active matrix substrate in which a plurality of pixel electrodes having slits are provided in a matrix, a counter substrate, a vertically aligned liquid crystal layer sandwiched between both substrates, and an active matrix substrate are formed. Auxiliary capacitor for holding the potential of the pixel electrode 7, a pixel defined for each pixel electrode 7, a plurality of domains constituting the pixel and divided along the slit 7f, and for each domain The auxiliary capacitor formed of the electrode 4c is formed so as to overlap the slit 7f.
[Selection] Figure 1

Description

  The present invention relates to a vertical alignment type liquid crystal display device having a wide viewing angle.

  2. Description of the Related Art In recent years, liquid crystal display devices that are attracting attention as displays are widely used for OA devices such as personal computers, portable information devices such as mobile phones and PDAs (Personal Digital Assistants), taking advantage of their thinness and low power consumption. It has been.

  In particular, an active matrix liquid crystal display device includes a switching element such as a thin film transistor (TFT) for each pixel, which is the minimum unit of an image, and thus can display a fine image.

  This active matrix type liquid crystal display device has a well-balanced characteristic that is basically required for a display, such as high contrast, relatively high response speed, low drive voltage, and easy gradation display. Therefore, a TN (Twisted Nematic) type display method is often used. This TN type liquid crystal display device is configured to change the alignment direction of two upper and lower alignment films in contact with a liquid crystal layer formed of liquid crystal molecules so that the liquid crystal molecules are twisted when no voltage is applied. Has been.

  However, the TN liquid crystal display device has a problem that the viewing angle characteristic varies depending on the viewing direction and the viewing angle is narrow. In order to solve this viewing angle problem, vertical alignment type display systems using liquid crystal molecules having a negative dielectric anisotropy (Δε <0) have been proposed (for example, Patent Documents 1, 2, and 3). Etc.).

  For example, FIG. 12 is a schematic plan view of a liquid crystal display device 150a corresponding to the liquid crystal display device disclosed in Patent Documents 1 and 2, and FIG. 13 is a sectional view taken along line XIII-XIII in FIG. 14 is a cross-sectional view taken along line XIV-XIV in FIG.

  The liquid crystal display device 150a includes an active matrix substrate 120a, a counter substrate 130a, and a liquid crystal layer 140 sandwiched between the substrates 120a and 130a.

  The active matrix substrate 120a is obtained by arranging pixel electrodes 107 constituting one pixel in a matrix. The pixel electrode 107 has slits 107f each having a notch 107d and an opening 107e. A total of 12 sub-electrodes 107a in 6 columns and 2 rows are connected to each other and the sub-electrodes 107a are connected to each other. Part 107b.

  In the active matrix substrate 120a, a plurality of gate lines 101 extending in parallel to each other and a plurality of source lines 104 extending in a direction orthogonal to the gate lines 101 are provided along the peripheral edge of the pixel electrode 107, respectively. A capacitor line 101 b extending in parallel with the gate line 101 is provided between the gate lines 101, and a TFT 109 is provided at each intersection of the gate line 101 and the source line 104.

  The counter substrate 130a has a multilayer stacked structure in which a color filter layer 111, a common electrode 112, and an alignment film 108 are stacked in this order on an insulating substrate 110. Between the common electrode 112 and the alignment film 108, a rivet-shaped alignment regulating material (hereinafter referred to as “rivet”) protruding in an island shape corresponding to each sub-electrode 107a on the active matrix substrate 120a. 113a is provided. Here, the rivet 113a is for forming an alignment center in each sub-electrode 107a.

  The liquid crystal layer 140 is a nematic liquid crystal having electro-optical characteristics, and is composed of liquid crystal molecules having Δε <0.

  In this liquid crystal display device 150a, when no voltage is applied to the liquid crystal layer 140, only the liquid crystal molecules in the vicinity of each rivet 113a are radially inclined and centered around the rivet 113a and separated from the other rivets 113a. When the liquid crystal molecules are aligned substantially perpendicular to the surface of the active matrix substrate 120a (counter substrate 130a) and a voltage is applied to the liquid crystal layer 140, the liquid crystal molecules separated from the rivets 113a are also in the above-mentioned radial tilt alignment. It is thought to be oriented to match. Further, since the pixel is divided into a plurality of domains along the slit 107f, the alignment of liquid crystal molecules is divided for each domain. Therefore, the viewing angle characteristics during image display are uniform over all directions, and the viewing angle is widened.

  As another example, FIG. 15 is a schematic plan view of a liquid crystal display device 150b corresponding to the liquid crystal display device disclosed in Patent Document 3, and FIG. 16 is a sectional view taken along line XVI-XVI in FIG. .

  As with the liquid crystal display device 150a, the liquid crystal display device 150b includes an active matrix substrate 120b, a counter substrate 130b, and a liquid crystal layer 140 sandwiched between the substrates 120b and 130b.

  In the active matrix substrate 120b, the pixel electrodes 107 provided corresponding to the respective TFTs 109 are arranged in an oblique direction in FIG. 15 (upper left to lower right direction in the upper half region and lower left to upper right direction in the lower half region. ) Is different from the configuration of the active matrix substrate 120a.

  The counter substrate 130b has a multi-layered structure like the counter substrate 130a, and the alignment control is performed between the common electrode 112 and the alignment film 108 so as to extend between the slits 107f on the active matrix substrate 120b. A material 113b is provided.

  Here, the orientation regulating member 113b is a protruding portion that protrudes in the shape of a half-moon having a transverse cross section, and is for forming an alignment center in each domain divided along the slit 107f.

In the liquid crystal display device 150b, when no voltage is applied to the liquid crystal layer 140, only the liquid crystal molecules in the vicinity of each alignment control material 113b are inclined and aligned in a plane orthogonal to the direction in which the alignment control material 113b extends. When the liquid crystal molecules separated from the other alignment regulating materials 113b are aligned substantially perpendicular to the surface of the active matrix substrate 120b (opposing substrate 130b) and a voltage is applied to the liquid crystal layer 140, the alignment is performed. It is considered that liquid crystal molecules separated from the regulating material 113b are aligned so as to match the tilted alignment. Further, since the pixel is divided into a plurality of domains along the slit 107f, the alignment of liquid crystal molecules is divided for each domain. Therefore, when displaying an image, the viewing angle characteristics from the direction orthogonal to the slit 107f, that is, the oblique directions (upper left, lower left, upper right, and lower right) in FIG. 15 are improved, and the viewing angle is widened.
JP 2003-228073 A JP 2003-167253 A Japanese Patent Laid-Open No. 11-242225

  However, although the liquid crystal display device as described above has a wide viewing angle, there is a problem in that the aperture ratio of the pixel is lowered when an auxiliary capacitor for holding the applied voltage is formed in the pixel.

  Specifically, in the liquid crystal display device 150a, the two sub-electrodes 107a overlapping with the capacitor line 101b (capacitor electrode 104c) constituting the auxiliary capacitor 114 cannot be used for light transmission during image display. This is because the capacitor line 101b and the capacitor electrode 104c are generally formed of a light-shielding material such as a metal thin film, so that the region where the capacitor line 101b and the capacitor electrode 104c are disposed always blocks light. . As a result, by forming the auxiliary capacitor 114 in the pixel, the aperture ratio of the pixel is lowered.

  Similarly, in the liquid crystal display device 150b, the pixel electrode 107 in the region overlapping with the light-shielding capacitor line 101b (capacitor electrode 104c) cannot be used for light transmission at the time of image display. Will do.

  The present invention has been made in view of the above points, and an object of the present invention is to prevent a reduction in the aperture ratio of a pixel even when an auxiliary capacitor is formed in a liquid crystal display device having a wide viewing angle. There is.

  In the present invention, the auxiliary capacitor is formed so as to overlap with the slit of the pixel electrode.

  Specifically, the liquid crystal display device according to the present invention includes an active matrix substrate in which a plurality of pixel electrodes each having a slit that is at least one of an opening and a notch are provided in a matrix, and the active matrix substrate facing the active matrix substrate. A counter substrate disposed; a vertical alignment type liquid crystal layer sandwiched between the active matrix substrate and the counter substrate; and an auxiliary capacitor formed on the active matrix substrate for holding the potential of the pixel electrode; A liquid crystal display device comprising a pixel defined for each pixel electrode, and a plurality of domains constituting the pixel and divided along the slit, wherein the auxiliary capacitor is provided in the slit. On the other hand, the active matrix substrate is formed so as to overlap with the normal direction.

  On the liquid crystal layer side of the counter substrate, a protruding portion that protrudes for each of the domains may be provided.

  The active matrix substrate includes a plurality of gate lines extending in parallel with each other between the pixel electrodes, a plurality of source lines orthogonal to the plurality of gate lines between the pixel electrodes, the source lines, and the A switching element that switches an electrical connection with the pixel electrode, the slit is formed along both the gate line and the source line, and the auxiliary capacitor includes a capacitor electrode connected to the switching element, A capacitive line disposed opposite to the capacitive electrode, the capacitive line extending from the capacitive trunk line, and extending from the capacitive trunk line, the gate line and the source line You may be comprised by the capacity | capacitance branch line extended along both.

  The active matrix substrate includes a plurality of gate lines extending in parallel with each other between the pixel electrodes, and a plurality of source lines extending in parallel with each other so as to be orthogonal to the plurality of gate lines between the pixel electrodes. And a switching element for switching electrical connection between the source line and the pixel electrode, the slit is formed to extend obliquely with respect to the gate line and the source line, and the auxiliary capacitance is A capacitance electrode connected to the switching element, and a capacitance line disposed opposite to the capacitance electrode, the capacitance line extending along the gate line, and extending from the capacitance trunk line. And a capacity branch line that extends along the slit.

  Next, the operation of the present invention will be described.

  According to the liquid crystal display device of the present invention, since the liquid crystal layer is of the vertical alignment type, when a voltage is applied to the liquid crystal layer, for example, the liquid crystal molecules are in a radially inclined alignment state around the protrusion. A multi-tone display is possible by changing the alignment state of the liquid crystal layer in accordance with the magnitude of the voltage applied to the liquid crystal layer. In each domain in this radially inclined alignment state, the alignment direction of the liquid crystal molecules is distributed in all azimuth directions, so that a wide viewing angle characteristic can be obtained.

  In addition, since the alignment force of the liquid crystal molecules becomes weaker when they are separated from the protrusions that function as the alignment regulating material, the response speed is reduced and light leakage occurs in the region away from the protrusions with weak alignment force. There is a risk of degrading the quality. However, in the present invention, since one pixel is divided into a plurality of domains by the slits (at least one of the opening and the cutout) of each pixel electrode, the degradation of display quality is suppressed.

  Further, the auxiliary capacitor for holding the potential of the pixel electrode is formed so as to overlap the slit of the pixel electrode, and the region where the slit is formed is not used for light transmission at the time of image display. By forming the auxiliary capacitor, the aperture ratio of the pixel is not lowered. Therefore, in the liquid crystal display device having a wide viewing angle, the aperture ratio of the pixel does not decrease even if an auxiliary capacitor is formed.

  In addition, when the slit is formed along both the gate line and the source line, one pixel is divided through the slit. Therefore, by forming a plurality of domains, one pixel is formed. It becomes possible to divide the alignment of the liquid crystal layer into a plurality. Since each domain is formed in a matrix along both the gate line and the source line, the viewing angle characteristics are uniform in all directions.

  Further, in the case where the slit is formed so as to extend obliquely with respect to the gate line and the source line, one pixel is divided through the slit. Therefore, by forming a plurality of domains, 1 The alignment of the liquid crystal layer can be divided into a plurality of pixels within one pixel. Since each domain is formed continuously in an oblique direction with respect to the gate line and the source line, from the oblique direction with respect to the gate line and the source line, specifically, in the direction in which the slit extends. Thus, the viewing angle characteristics from the oblique direction orthogonal to each other are improved.

  According to the present invention, since the auxiliary capacitance is formed so as to overlap with the slit of the pixel electrode, it is possible to prevent the aperture ratio of the pixel from being lowered even if the auxiliary capacitance is formed.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In addition, this invention is not limited to the following embodiment, Other structures may be sufficient.

Embodiment 1 of the Invention
FIG. 1 is a schematic plan view showing one pixel of a liquid crystal display device 50a according to Embodiment 1 of the present invention, and FIG. 3 is a cross-sectional view taken along line III-III in FIG. 2 is a cross-sectional view taken along the line II-II in FIG.

  As shown in FIGS. 2 and 3, the liquid crystal display device 50a is sandwiched between an active matrix substrate 20a, a counter substrate 30a disposed to face the active matrix substrate 20a, and both the substrates 20a and 30a. And a liquid crystal layer 40.

  The active matrix substrate 20a is a substrate in which pixel electrodes 7 constituting one pixel are provided in a matrix. Here, the pixel electrode 7 has slits 7f including notches 7d and openings 7e extending in the vertical and horizontal directions in FIG. 1, and a total of 12 sub-electrodes in 6 columns and 2 rows. 7a and a connecting portion 7b that connects the sub-electrodes 7a.

  Hereinafter, the configuration of the active matrix substrate 20a will be described in detail.

  The active matrix substrate 20a has a multilayer laminated structure in which a gate insulating film 2, a first interlayer insulating film 5, a second interlayer insulating film 6, and an alignment film 8 are sequentially stacked on an insulating substrate 10.

  Between the insulating substrate 10 and the gate insulating film 2, there are a plurality of gate lines 1, a gate electrode 1 a, and a capacitor line 1 d composed of a capacitor trunk line 1 b and a capacitor branch line 1 c.

  The gate line 1 is provided so as to extend in parallel with each other in the horizontal direction in FIG. 1 along the peripheral edge of the pixel electrode 7, and a protruding portion protruding to the side is a gate electrode 1 a. The capacity trunk line 1b is provided between the gate lines 1 so as to overlap the slit 7f extending in the horizontal direction in FIG. The capacity branch line 1c extends from the capacity trunk line 1b, and is provided so as to overlap with the slits 7f extending in the vertical direction and the horizontal direction in FIG.

  Between the gate insulating film 2 and the first interlayer insulating film 5, a semiconductor layer 3 formed in an island shape at a position corresponding to the gate electrode 1a, a plurality of source lines 4, and formed on the semiconductor layer 3 In addition, a source electrode 4a and a drain electrode 4b provided so as to face each other, and a capacitor electrode 4c in which the drain electrode 4b is extended. The gate electrode 1a, the gate insulating film 2, the semiconductor layer 3, the source electrode 4a, and the drain electrode 4b constitute a TFT 9 that is a switching element.

  The source line 4 is provided so as to extend in parallel with each other in the vertical direction in FIG. 1 along the peripheral edge of the pixel electrode 7, and a protruding portion protruding to the side is a source electrode 4 a. The capacitive electrode 4c is provided so as to be opposed to the capacitive line 1d (the capacitive trunk line 1b and the capacitive branch line 1c).

  Between the second interlayer insulating film 6 and the alignment film 8, the pixel electrode 7 connected to the drain electrode 4b through the contact hole 7c is provided.

  Next, the counter substrate 30a and the liquid crystal layer 40 will be described.

  As shown in FIGS. 2 and 3, the counter substrate 30 a has a stacked structure in which the color filter layer 11, the common electrode 12, and the alignment film 8 are sequentially stacked on the insulating substrate 10.

  The color filter layer 11 is provided with a colored layer 11a of one color of red, green, and blue corresponding to each pixel, and a black matrix 11b is provided between the colored layers 11a. The black matrix 11b is provided so as to cover the TFT 9 on the active matrix substrate 20a.

  Between the common electrode 12 and the alignment film 8, rivets 13a protruding in an island shape are provided corresponding to the sub-electrodes 7a on the active matrix substrate 20a. Here, the rivet 13a is for forming an alignment center in each sub-electrode 7a.

  The liquid crystal layer 40 has a negative dielectric anisotropy (Δε <0) and is a vertically aligned nematic liquid crystal.

  In this vertical alignment type liquid crystal layer 40, when no voltage is applied to the liquid crystal layer 40, only the liquid crystal molecules in the vicinity of each rivet 13a are radially inclined with the rivet 13a as a center, and each of the other rivets 13a. When the liquid crystal molecules separated from the rivets 13a are aligned substantially perpendicular to the surface of the active matrix substrate 20a (opposing substrate 30a) and a voltage is applied to the liquid crystal layer 40, the liquid crystal molecules separated from the rivets 13a are also radially It is considered to be aligned to match the tilted alignment.

  In the liquid crystal display device 50 a having such a configuration, a gate signal (address signal) is supplied to the gate line 1, and a source signal (display signal) is supplied to the source line 4. This display signal is written to each pixel electrode 7 through the TFT 9 which is ON / OFF controlled by the address signal. As a result, a potential difference is generated between the pixel electrode 7 and the common electrode 12, and the liquid crystal capacitance formed by the liquid crystal layer 40, the capacitor line 1d (capacitor main line 1b and capacitor branch line 1c), the capacitor electrode 4c, and these A predetermined voltage is applied to the auxiliary capacitor 14 constituted by the gate insulating film 2 sandwiched between the two. In the liquid crystal display device 50a, an image is displayed by adjusting the transmittance of light incident from the outside by utilizing the fact that the alignment state of liquid crystal molecules changes according to the magnitude of the applied voltage.

  Next, an example is given and demonstrated about the manufacturing method of the liquid crystal display device 50a.

<Active matrix substrate manufacturing process>
Hereinafter, a manufacturing process of the active matrix substrate will be described.

  Here, FIG. 4, FIG. 5 and FIG. 6 are schematic plan views showing respective steps for producing an active matrix substrate. In addition, the area | region of the hatching pattern in a figure shows the shape of the pattern formed at each process.

  First, a titanium film (thickness of about 30 nm), an aluminum film (thickness of about 100 nm), and a titanium nitride film (thickness of about 50 nm) are sequentially formed on the entire substrate on the insulating substrate 10 such as a glass substrate by a sputtering method. Thereafter, a pattern is formed by the PEP technique to form a gate layer having the gate line 1, the gate electrode 1a, and the capacitor line 1d (capacitor trunk line 1b and capacitor branch line 1c) as shown in FIG.

  Next, a silicon nitride film (having a thickness of about 400 nm) or the like is formed on the entire substrate on which the gate layer has been formed by plasma CVD, and the gate insulating film 2 is formed.

  Next, an intrinsic amorphous silicon film (thickness of about 130 nm) and a phosphorus-doped n + amorphous silicon film (thickness of about 40 nm) are successively formed on the entire substrate on the gate insulating film 2 by plasma CVD. To do. Thereafter, an island pattern is formed on the gate electrode 1a by the PEP technique to form the semiconductor layer 3 constituted by an intrinsic amorphous silicon layer and an n + amorphous silicon layer.

  Here, although the semiconductor layer 3 may be formed from an amorphous silicon film as described above, a polysilicon film may be formed, or laser annealing is performed on the amorphous silicon film and the polysilicon film. Crystallinity may be improved.

  Next, a titanium film (thickness: 30 nm) and an aluminum film (thickness: about 100 nm) are sequentially formed by sputtering on the entire substrate on the gate insulating film 2 on which the semiconductor layer 3 is formed. Thereafter, a pattern is formed by a PEP technique to form a source layer having a source line 4, a source electrode 4a, a drain electrode 4b, and a capacitor electrode 4c, as shown in FIG.

  Next, the n + amorphous silicon layer of the semiconductor layer 3 is removed by etching using the source electrode 4a and the drain electrode 4b as a mask, thereby forming the channel portion 3a.

  Next, a silicon nitride film (thickness of about 300 nm) or the like is formed on the entire substrate on which the source layer is formed using a plasma CVD method, and then an acrylic resin film (thickness of about 3000 nm) is formed by spin coating. The first interlayer insulating film 5 and the second interlayer insulating film 6 are formed in this order.

  Next, portions of the first interlayer insulating film 5 and the second interlayer insulating film 6 corresponding to the drain electrode 4b are removed by etching to form contact holes 7c.

  Next, a transparent conductive film (thickness of about 100 nm) made of an ITO (Indium Tin Oxide) film is formed on the entire substrate on the second interlayer insulating film 6 by a sputtering method. Thereafter, the opening 7e and the notch 7d (slit 7f) are patterned by the PEP technique to form the pixel electrode 7 constituted by the sub-pixel 7a and the connecting portion 7b as shown in FIG.

  Next, an alignment film 8 is formed on the entire substrate on the pixel electrode 7 by applying a polyimide resin by a printing method.

  As described above, the active matrix substrate 20a constituting the present invention can be manufactured.

<Opposite substrate manufacturing process>
Hereinafter, a manufacturing process of the counter substrate will be described.

  First, after forming a chromium thin film with a thickness of about 100 nm on the entire substrate on the insulating substrate 10 such as a glass substrate, the black matrix 11b is formed by pattern formation by the PEP technique.

  Next, a color filter layer 11 is formed by patterning any one of red, green, and blue colored layers 11a with a thickness of about 2 μm between the black matrices 11b.

  Next, an ITO film is formed with a thickness of about 150 nm on the entire substrate on the color filter layer 11 to form the common electrode 12.

  Next, a photosensitive acrylic resin or the like is applied to the entire substrate on the common electrode 12, and then a pattern is formed by the PEP technique so as to correspond to the sub-electrode 7a on the active matrix substrate 20a, thereby forming the rivet 13a. .

  Subsequently, the alignment film 8 is formed by applying a polyimide resin by a printing method.

  As described above, the counter substrate 30a constituting the present invention can be manufactured.

<Liquid crystal display device manufacturing process>
First, a seal material made of a thermosetting epoxy resin or the like is applied to one of the active matrix substrate 20a and the counter substrate 30a in a frame-like pattern lacking a liquid crystal injection port by screen printing, and a liquid crystal is applied to the other substrate. A spherical spacer made of resin having a diameter corresponding to the thickness of the layer is dispersed.

  Instead of spraying the spherical spacers, columnar spacers made of resin may be formed on the counter substrate 30a.

  Next, the active matrix substrate 20a and the counter substrate 30a are bonded together, the sealing material is cured, and empty cells are formed.

  Next, a liquid crystal material is injected between the active matrix substrate 20a and the counter substrate 30a of the empty cell by a decompression method to form the liquid crystal layer 40. Thereafter, a UV curable resin is applied to the liquid crystal injection port, the UV curable resin is cured by UV irradiation, and the liquid crystal injection port is sealed.

  As described above, the liquid crystal display device 50a of the present invention can be manufactured.

  According to the liquid crystal display device 50a, since the liquid crystal layer 40 is a vertical alignment type, when a voltage is applied to the liquid crystal layer 40, the liquid crystal molecules are in a radially inclined alignment state around the rivet 13a. The multi-tone display can be performed by changing the alignment state of the liquid crystal layer 40 in accordance with the magnitude of the voltage applied to the liquid crystal layer 40. In each domain in this radially inclined alignment state, the alignment direction of the liquid crystal molecules is distributed in all azimuth directions, so that a wide viewing angle characteristic can be obtained.

  In general, the alignment force of the liquid crystal molecules becomes weaker when they are separated from the rivet 13a. Therefore, in a region away from the rivet 13a having a weak alignment force, the response speed may decrease, light leakage, etc., and the display quality may decrease. is there. However, in the liquid crystal display device 50a of the present invention, since one pixel is divided into a plurality of domains by the slits 7f (openings 7e and notches 7d) of each pixel electrode 7, it is possible to suppress deterioration in display quality. Can do. Further, since each domain is formed in a matrix along both the gate line 1 and the source line 4, the viewing angle characteristics are uniform in all directions.

  Furthermore, the auxiliary capacitor 14 for holding the potential of the pixel electrode 7 is formed so as to overlap the slit 7f. Specifically, the capacitor line 1d and the capacitor electrode 4c constituting the auxiliary capacitor 14 pass through the slit 7f. Since the opening 7e and the cutout 7d are formed so as to overlap with the normal direction of the active matrix substrate 20a (counter substrate 30a), a slit 7f that is not used for light transmission during image display is formed. The area is effectively used, and even if the light-shielding auxiliary capacitor 14 is formed, the aperture ratio of the pixel does not decrease.

  Further, in a liquid crystal display device having a wide viewing angle by alignment division like the conventional liquid crystal display device 150a, a slit 107f is formed between the sub-electrodes 107a, so that a voltage is directly applied to the liquid crystal layer 140. This is a region where there is no electrode for controlling the orientation of the liquid crystal molecules. For this reason, the alignment control of the liquid crystal molecules is disturbed in the vicinity of the peripheral edge of each sub-electrode 107a, and there is a possibility that the display quality is deteriorated. However, in the active matrix substrate 20a constituting the present invention, since the gate layer is disposed between the sub-electrodes 7a, the alignment disorder region near the peripheral edge of the sub-pixel electrode 7a is shielded by the gate layer. And display quality is improved. In addition, it is possible to obtain an effect of reducing display variations between products and within products due to manufacturing variations of the slit 107f.

  Furthermore, the electric field tends to concentrate at the peripheral edge of each sub-electrode 107a, and there is a possibility that a printing phenomenon may occur by displaying the same image for a long time. However, in the active matrix substrate 20a constituting the present invention, since the gate layer is arranged and shielded from light at the peripheral edge of the sub-electrode 7a where the seizure is likely to occur, the level of the seizure can be lowered.

  As described above, in the liquid crystal display device 50a of the present invention having a wide viewing angle, the aperture ratio of the pixel can be prevented from being lowered even if the auxiliary capacitor 14 is formed.

<< Embodiment 2 of the Invention >>
FIG. 7 is a schematic plan view showing one pixel of the liquid crystal display device 50b according to Embodiment 2 of the present invention, and FIG. 8 is a sectional view taken along line VIII-VIII in FIG. The same parts as those in FIGS. 1, 2, and 3 are denoted by the same reference numerals, and detailed description thereof is omitted.

  The liquid crystal display device 50b includes an active matrix substrate 20b, a counter substrate 30b disposed to face the active matrix substrate 20b, and a liquid crystal layer 40 sandwiched between the substrates 20b and 30b.

  The active matrix substrate 20b is a substrate in which pixel electrodes 7 constituting one pixel are provided in a matrix.

  Here, the pixel electrode 7 has a slit 7f extending in the diagonally vertical direction in FIG. The slit 7f is formed so as to extend from the upper left to the lower right in the upper half region in FIG. 7, and to extend from the lower left to the upper right in the lower half region in FIG.

  Hereinafter, the configuration of the active matrix substrate 20b will be described in detail focusing on differences from the active matrix substrate 20a described in the first embodiment.

  The active matrix substrate 20b has a multilayer stacked structure in which a gate insulating film 2, a first interlayer insulating film 5, a second interlayer insulating film 6, and an alignment film 8 are sequentially stacked on an insulating substrate 10.

  Between the insulating substrate 10 and the gate insulating film 2, as in the first embodiment, there are a plurality of gate lines 1, a gate electrode 1a, and a capacitor line 1d composed of a capacitor trunk line 1b and a capacitor branch line 1c. is doing.

  The capacity branch line 1c is extended from the capacity trunk line 1b, and is provided so as to overlap the slit 7f extending in the oblique direction in FIG.

  As in the first embodiment, between the gate insulating film 2 and the first interlayer insulating film 5, a semiconductor layer 3 formed in an island shape at a position corresponding to the gate electrode 1a, a plurality of source lines 4, A source electrode 4a and a drain electrode 4b are formed on the semiconductor layer 3 so as to be opposed to each other, and a capacitor electrode 4c in which the drain electrode 4b is extended.

  As in the first embodiment, the pixel electrode 7 connected to the drain electrode 4b via the contact hole 7c is provided between the second interlayer insulating film 6 and the alignment film 8.

  Next, the counter substrate 30b will be described.

  The counter substrate 30 b has a stacked structure in which the color filter layer 11, the common electrode 12, and the alignment film 8 are sequentially stacked on the insulating substrate 10.

  An alignment regulating material 13b is provided between the common electrode 12 and the alignment film 8 so as to extend between the slits 7f on the active matrix substrate 20b.

  Here, the orientation regulating member 13b is a protruding portion that protrudes in a rib shape having a semicircular cross section, and is for forming an alignment center in each domain divided along the slit 7f.

  In the vertical alignment type liquid crystal layer 40, when no voltage is applied to the liquid crystal layer 40, the liquid crystal layer 40 is tilted and aligned in a plane orthogonal to the direction in which the alignment control material 13b extends, and is separated from the other alignment control materials 13b. When the liquid crystal molecules are aligned substantially perpendicular to the surface of the active matrix substrate 20b (counter substrate 30b) and a voltage is applied to the liquid crystal layer 40, the liquid crystal molecules separated from the alignment regulating members 13b are also inclined. It is considered that the alignment is aligned with the alignment.

  As for the manufacturing method of the liquid crystal display device 50b, in the manufacturing method of the liquid crystal display device 50a described in the first embodiment, specifically, in the active matrix substrate manufacturing step, the gate layer is formed as a source layer as shown in FIG. As shown in FIG. 10, the pixel electrode 7 is formed as shown in FIG. 11, and the pattern shape of the rivet 13a may be changed in the counter substrate manufacturing step, and the description thereof is omitted.

  According to the liquid crystal display device 50b, as in the first embodiment, since the liquid crystal layer 40 is a vertical alignment type, when a voltage is applied to the liquid crystal layer 40, the liquid crystal molecules are tilted with the alignment regulating material 13b as the center. Take the state. The multi-tone display can be performed by changing the alignment state of the liquid crystal layer 40 in accordance with the magnitude of the voltage applied to the liquid crystal layer 40. In a pixel having each domain in this inclined alignment state, the alignment direction of the liquid crystal molecules is distributed in all azimuth directions, so that a wide viewing angle characteristic can be obtained.

  In general, the alignment force of the liquid crystal molecules becomes weaker when they are separated from the alignment restricting material 13b. Therefore, in a region away from the alignment restricting material 13b having a weak alignment force, a response speed is reduced, light leaks, etc., resulting in a display quality. May fall. However, in the liquid crystal display device 50b of the present invention, since one pixel is divided into a plurality of domains by the slits 7f of each pixel electrode 7, it is possible to suppress deterioration in display quality. Further, each domain is formed continuously in an oblique direction with respect to the gate line 1 and the source line 4, and specifically, from the oblique direction with respect to the gate line 1 and the source line 4, specifically, the slit 7 f. The viewing angle characteristics from the oblique direction orthogonal to the extending direction of the image, more specifically, from the oblique directions (upper left, lower left, upper right and lower right) in FIG. 7 are improved.

  Further, the auxiliary capacitor 14 for holding the potential of the pixel electrode 7 is formed so as to overlap the slit 7f as in the first embodiment. Specifically, the capacitor line 1d constituting the auxiliary capacitor 14 and Since the capacitor electrode 4c is formed so as to overlap the slit 7f in the normal direction of the active matrix substrate 20b (counter substrate 30b), the region where the slit 7f that is not used for light transmission at the time of image display is formed is effective. Therefore, even if the light-shielding auxiliary capacitor 14 is formed, the aperture ratio of the pixel can be prevented from being lowered.

  In the above embodiment, the alignment center of the liquid crystal molecules is exemplified by the rivet 13a or the alignment regulating member 13b protruding on the counter substrate. However, the pixel electrode on the active matrix substrate or the common electrode on the counter substrate is exemplified. It is also possible to form the opening for the purpose of controlling the electric field to make the alignment center of the liquid crystal molecules.

  As described above, the present invention is useful for a liquid crystal panel having a wide viewing angle because an auxiliary capacitor can be formed without reducing the aperture ratio of the pixel.

It is a plane schematic diagram of the liquid crystal display device 50a which concerns on Embodiment 1 of this invention. It is the II-II sectional view taken on the line in FIG. It is the III-III sectional view taken on the line in FIG. It is a plane schematic diagram (gate layer) which shows the manufacturing process of the active matrix substrate 20a. It is a schematic plan view (source layer) showing a manufacturing process of the active matrix substrate 20a. It is a plane schematic diagram (pixel electrode) showing a manufacturing process of the active matrix substrate 20a. It is a plane schematic diagram of the liquid crystal display device 50b which concerns on Embodiment 2 of this invention. It is the VIII-VIII sectional view taken on the line in FIG. It is a plane schematic diagram (gate layer) which shows the manufacturing process of the active matrix substrate 20b. It is a plane schematic diagram (source layer) which shows the manufacturing process of the active matrix substrate 20b. It is a plane schematic diagram (pixel electrode) showing the manufacturing process of the active matrix substrate 20b. It is a plane schematic diagram of the conventional liquid crystal display device 150a. It is the XIII-XIII sectional view taken on the line in FIG. It is the XIV-XIV sectional view taken on the line in FIG. It is a plane schematic diagram of the conventional liquid crystal display device 150b. It is the XVI-XVI sectional view taken on the line in FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Gate line 1b Capacity | capacitance trunk line 1c Capacity | capacitance branch line 1d Capacity line 4 Source line 4c Capacity electrode 7 Pixel electrode 7d Notch part 7e Opening part 7f Slit 9 TFT (switching element)
13a Rivet (protruding part)
13b Orientation regulating material (protrusion)
14 Auxiliary capacitors 20a and 20b Active matrix substrates 30a and 30b Counter substrate 40 Liquid crystal layers 50a and 50b Liquid crystal display device

Claims (4)

An active matrix substrate in which a plurality of pixel electrodes each having a slit that is at least one of an opening and a notch are provided in a matrix;
A counter substrate disposed opposite to the active matrix substrate;
A vertically aligned liquid crystal layer sandwiched between the active matrix substrate and the counter substrate;
An auxiliary capacitor formed on the active matrix substrate for holding the potential of the pixel electrode;
A pixel defined for each pixel electrode;
A liquid crystal display device that constitutes the pixel and includes a plurality of domains divided along the slit,
The liquid crystal display device, wherein the auxiliary capacitor is formed so as to overlap with the slit in a normal direction of the active matrix substrate. The liquid crystal display device according to claim 1,
The liquid crystal display device according to claim 1, wherein a protruding portion that protrudes for each of the domains is provided on the liquid crystal layer side of the counter substrate. The liquid crystal display device according to claim 1 or 2,
The active matrix substrate includes a plurality of gate lines extending in parallel with each other between the pixel electrodes, a plurality of source lines orthogonal to the plurality of gate lines between the pixel electrodes, the source lines, and the A switching element for switching electrical connection with the pixel electrode,
The slit is formed along both the gate line and the source line,
The auxiliary capacitor has a capacitor electrode connected to the switching element, and a capacitor line disposed to face the capacitor electrode,
The capacitor line is composed of a capacitor main line extending along the gate line and a capacitor branch line extending from the capacitor main line and extending along both the gate line and the source line. Display device. The liquid crystal display device according to claim 1 or 2,
The active matrix substrate includes a plurality of gate lines extending in parallel with each other between the pixel electrodes, and a plurality of source lines extending in parallel with each other so as to be orthogonal to the plurality of gate lines between the pixel electrodes. And a switching element for switching electrical connection between the source line and the pixel electrode,
The slit is formed to extend in an oblique direction with respect to the gate line and the source line,
The auxiliary capacitor has a capacitor electrode connected to the switching element, and a capacitor line disposed to face the capacitor electrode,
2. The liquid crystal display device according to claim 1, wherein the capacitor line includes a capacitor trunk extending along the gate line, and a capacitor branch extending from the capacitor trunk and extending along the slit.

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