JP5292320B2 - Liquid crystal display - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an MVA mode liquid crystal display which is capable of further improving virtual aperture ratio. <P>SOLUTION: The liquid crystal device includes a TFT 214 in each pixel, and a pixel electrode 215 which is electrically connected to the TFT 214. The TFT 214 is connected to a gate bus line 211 and a data bus line 212. One pixel is divided into four regions, and a fine electrode part 215b which extends into different direction by each region is provided at the pixel electrode 215. Also, a cut portion is provided at the part which is the chip part of the fine electrode part 215b but does not contribute to aligning liquid crystal molecules in the direction of a slit 215a, that is the part which has no opposing fine electrode part. <P>COPYRIGHT: (C)2010,JPO&amp;INPIT

Description

  The present invention relates to an MVA (Multi-domain Vertical Alignment) mode liquid crystal display device, and more particularly to a liquid crystal display device in which a polymer that determines the direction in which liquid crystal molecules are tilted when a voltage is applied is formed in a liquid crystal layer.

  In general, a liquid crystal display device includes a liquid crystal panel in which liquid crystal is sealed between two substrates and polarizing plates disposed on both sides of the liquid crystal panel. A pixel electrode is formed for each pixel on one substrate of the liquid crystal panel, and a common electrode common to each pixel is formed on the other substrate. When a voltage is applied between the pixel electrode and the common electrode, the alignment direction of the liquid crystal molecules changes according to the voltage, and as a result, the amount of light transmitted through the liquid crystal panel and the polarizing plates on both sides thereof changes. A desired image can be displayed on the liquid crystal display device by controlling the applied voltage for each pixel.

  In a TN (Twisted Nematic) mode liquid crystal display device that has been widely used, liquid crystal having positive dielectric anisotropy is used, and liquid crystal molecules are twisted between two substrates. However, the TN mode liquid crystal display device has a disadvantage that viewing angle characteristics are not sufficient. In other words, in the TN mode liquid crystal display device, when the liquid crystal panel is viewed from an oblique direction, the color tone and contrast are remarkably deteriorated, and in extreme cases, the light and dark are reversed.

  As a liquid crystal display device with excellent viewing angle characteristics, an IPS (In-Plane Switching) mode liquid crystal display device and an MVA (Multi-domain Vertical Alignment) mode liquid crystal display device are known. In the IPS mode liquid crystal display device, linear pixel electrodes and common electrodes are alternately arranged on one substrate, and when a voltage is applied between these pixel electrodes and the common electrode, the voltage depends on the voltage. The direction of the liquid crystal molecules changes in a plane parallel to the substrate surface.

  However, although the IPS mode liquid crystal display device has excellent viewing angle characteristics, a voltage is applied in a direction parallel to the substrate surface, so that the orientation of the liquid crystal molecules above the pixel electrode and the common electrode can be controlled. Can not. Therefore, the IPS mode liquid crystal display device has a disadvantage that the substantial aperture ratio is low and the screen becomes dark unless a strong backlight is used.

  In the MVA mode liquid crystal display device, a pixel electrode is formed on one substrate, and a common electrode is formed on the other substrate. Further, in a general MVA mode liquid crystal display device, a bank-like protrusion made of a dielectric extending in an oblique direction is formed on a common electrode, and a slit parallel to the protrusion is provided on the pixel electrode. ing.

  In an MVA mode liquid crystal display device, liquid crystal molecules are aligned in a direction perpendicular to the substrate surface when no voltage is applied. When a voltage is applied between the pixel electrode and the common electrode, the liquid crystal molecules are It is tilted and oriented at an appropriate angle. At this time, a plurality of regions (domains) in which the liquid crystal molecules fall in different directions are formed in one pixel by slits and bank-like projections provided in the pixel electrode. In this manner, by forming a plurality of regions in which the liquid crystal molecules are tilted in different directions in one pixel, good viewing angle characteristics can be obtained.

  However, in the above-described MVA mode liquid crystal display device, the substantial aperture ratio is reduced due to the slits and protrusions. Therefore, although not as much as the IPS mode liquid crystal display device, the MVA mode liquid crystal display device is substantially different from the TN mode liquid crystal display device. An aperture ratio is low and a strong backlight is required. For this reason, this type of MVA mode liquid crystal display device is hardly employed in notebook personal computers that require low power consumption.

  Japanese Patent Application Laid-Open No. 2003-149647 discloses an MVA mode liquid crystal display device developed to eliminate the above-mentioned drawbacks. FIG. 1 is a plan view showing the MVA mode liquid crystal display device. Note that FIG. 1 shows a region for two pixels.

  A plurality of gate bus lines 11 extending in the horizontal direction (X-axis direction) and a plurality of data bus lines 12 extending in the vertical direction (Y-axis direction) are formed on one substrate constituting the liquid crystal panel. Yes. An insulating film (gate insulating film) is formed between the gate bus line 11 and the data bus line 12, and the gate bus line 11 and the data bus line 12 are electrically separated. Each rectangular area defined by the gate bus line 11 and the data bus line 12 is a pixel area.

  In each pixel region, a TFT (Thin Film Transistor) 14 and a pixel electrode 15 are formed. As shown in FIG. 1, the TFT 14 uses a part of the gate bus line 11 as a gate electrode, and a semiconductor film (not shown) serving as an active layer of the TFT 14 is formed above the gate electrode. A drain electrode 14a and a source electrode 14b are connected to both sides of the semiconductor film in the Y-axis direction. The source electrode 14 b of the TFT 14 is electrically connected to the data bus line 12, and the drain electrode 14 a is electrically connected to the pixel electrode 15.

  In the present application, of the two electrodes connected to the semiconductor film serving as the active layer of the TFT, the electrode connected to the data bus line is called a source electrode, and the electrode connected to the pixel electrode is called a drain electrode. Yes.

  The pixel electrode 15 is formed of a transparent conductor such as ITO (Indium-Tin Oxide). In the pixel electrode 15, slits 15 a are formed so that the alignment directions of liquid crystal molecules when a voltage is applied are four directions. That is, the pixel electrode 15 is divided into four regions with a center line parallel to the X axis and a center line parallel to the Y axis as boundaries. A plurality of slits 15a extending in a direction of 45 ° with respect to the X axis is formed in the first region (upper right region), and a direction of 135 ° with respect to the X axis is formed in the second region (upper left region). A plurality of slits 15a extending in the direction of 225 ° with respect to the X-axis are formed in the third region (lower left region), and the fourth region (lower right region). Are formed with a plurality of slits 15a extending in the direction of 315 ° with respect to the X-axis. A vertical alignment film (not shown) made of polyimide is formed on the pixel electrode 15.

  On the other substrate, a black matrix, a color filter, and a common electrode are formed. The black matrix is made of, for example, a metal such as Cr (chrome) or a black resin, and is disposed at a position facing the gate bus line 11, the data bus line 12, and the TFT 14. There are three types of color filters, red, green and blue, and one color filter is arranged for each pixel. The common electrode is made of a transparent conductor such as ITO and is formed on the color filter. A vertical alignment film made of polyimide is formed on the common electrode.

  These two substrates are arranged to face each other with a spacer (not shown) interposed therebetween, and a liquid crystal having negative dielectric anisotropy is sealed between them to constitute a liquid crystal panel. . Hereinafter, of the two substrates constituting the liquid crystal panel, the substrate on which the TFT is formed is referred to as a TFT substrate, and the substrate disposed to face the TFT substrate is referred to as a counter substrate.

  In the MVA mode liquid crystal display device shown in FIG. 1, when no voltage is applied to the pixel electrode 15, the liquid crystal molecules are aligned substantially perpendicular to the substrate surface. When a voltage is applied to the pixel electrode 15, as schematically shown in FIG. 1, the liquid crystal molecules 10 are tilted in the direction in which the slits 15a extend, and the tilt directions of the liquid crystal molecules are different from each other in one pixel. A region (domain) is formed. Thereby, light leakage in an oblique direction is suppressed, and good viewing angle characteristics are ensured.

  By the way, in the MVA mode liquid crystal display device shown in FIG. 1, immediately after the voltage is applied to the pixel electrode 15, the liquid crystal molecules 10 are tilted inward (in the direction toward the center of the pixel) or outward (in the direction toward the outside of the pixel). ) Is not decided whether to fall. First, the direction in which the liquid crystal molecules 10 on the tip side (data bus line 12 side) of the slit 15a falls is determined inward by the electric field at the end of the pixel electrode 15, and then the direction in which the liquid crystal molecules 10 fall propagates toward the center of the pixel. I will do it. For this reason, it takes time for all the liquid crystal molecules 10 in one pixel to fall in a predetermined direction, and there is a disadvantage that the response time becomes long.

  In the above-mentioned Japanese Patent Application Laid-Open No. 2003-149647, a liquid crystal added with a polymerization component (monomer) is sealed between a pair of substrates, and a voltage is applied between the pixel electrode and the common electrode so that the liquid crystal is directed in a predetermined direction. It is described that after the alignment, ultraviolet rays are irradiated to polymerize a polymerization component to form a polymer in a liquid crystal layer. In the liquid crystal display device thus manufactured, the direction in which the liquid crystal molecules are tilted is determined by the polymer in the liquid crystal layer, so that all of the pixels in the pixel are simultaneously applied with a voltage between the pixel electrode and the common electrode. The liquid crystal molecules start to fall in a predetermined direction, and the response time is remarkably shortened.

  JP-A-11-95221 and JP-A-8-36186 also describe the addition of a polymerization component to the liquid crystal.

JP 2003-149647 A JP-A-11-95221 JP-A-8-36186

  Generally, in a vertical alignment (VA) mode liquid crystal display device, it is known that the gradation luminance characteristic when viewed from the front is different from the gradation luminance characteristic when viewed from an oblique direction. The mode liquid crystal display device has the same drawbacks. FIG. 2 shows gradation luminance characteristics and directions of 90 ° azimuth and 60 ° polar angle when viewed from the front in an MVA mode liquid crystal display device, with gradation on the horizontal axis and transmittance on the vertical axis. It is a figure which shows the gradation luminance characteristic when it sees from (the diagonally upper direction). In this application, the angle between the straight line formed by projecting the line of sight on the liquid crystal panel and the X axis of the liquid crystal panel is called the azimuth, and the angle formed between the normal line and the line of sight of the liquid crystal panel. Is called the polar angle. In FIG. 2, the area from black to white is divided into 256 gradations. Each gradation corresponds to a voltage applied to the pixel electrode, and the voltage applied to the pixel electrode increases as the gradation value increases. Furthermore, in FIG. 2, the transmittance is shown as a relative value when the transmittance (Twhite) during white display is 1.

  As can be seen from FIG. 2, in the conventional MVA mode liquid crystal display device, the gradation transmittance characteristic when viewed from the front is greatly different from the gradation transmittance characteristic when viewed from the oblique direction. In this case, a good display quality can be obtained, but there is a drawback that the display quality deteriorates when viewed from an oblique direction. In particular, as can be seen from FIG. 2, in the conventional MVA mode liquid crystal display device, the gradation transmittance characteristic when viewed from an oblique direction is larger than the gradation transmittance characteristic when viewed from the front, The brightness difference is reduced during intermediate gradation display. For this reason, when viewed from an oblique direction, a phenomenon that the image looks whitish compared to when viewed from the front (wash out) occurs, and display quality deteriorates. In addition, since the refractive index anisotropy of the liquid crystal has a wavelength dependency, the color may change between when viewed from the front and when viewed from an oblique direction.

  Furthermore, the slits 15a of the pixel electrode 15 as shown in FIG. 1 are formed by photolithography, but the slit width is reduced due to variations in the film thickness of the photoresist film and a slight difference in exposure amount (shot unevenness) during stepper exposure. Variation occurs. This causes variations in the optical characteristics of the pixels and causes display unevenness. For example, a tile-like pattern may be seen when halftone display is performed on the entire panel surface.

  Furthermore, it is desired to improve the substantial aperture ratio and further reduce the power consumption. Furthermore, further improvement in response characteristics is desired for recent liquid crystal display devices.

  In view of the above, an object of the present invention is to provide an MVA mode liquid crystal display device which has a high substantial aperture ratio and can be applied to a notebook personal computer, and has a good display quality when viewed from an oblique direction. is there.

  Another object of the present invention is to provide an MVA mode liquid crystal display device capable of further improving the substantial aperture ratio.

  Still another object of the present invention is an MVA mode liquid crystal which has a high substantial aperture ratio and can be applied to a notebook personal computer, avoids display unevenness due to a photolithography process, and has a good display quality. It is to provide a display device.

  Still another object of the present invention is to provide an MVA mode liquid crystal display device which has a high substantial aperture ratio and can be applied to a notebook personal computer and has a good response characteristic.

The above-described problem is that the first and second substrates arranged opposite to each other, the liquid crystal having negative dielectric anisotropy sealed between the first and second substrates, and the liquid crystal A polymer that is formed by polymerizing the added polymerization component and determines a direction in which liquid crystal molecules fall when a voltage is applied, and the first substrate includes a gate bus line extending in a first direction, and the first substrate A data bus line extending in a second direction different from one direction, a switching element formed for each pixel and electrically connected to the gate bus line and the data bus line, formed for each pixel, A plurality of strip-like fine electrode portions extending obliquely with respect to the data bus line and a pixel electrode constituted by a connection electrode portion electrically connecting them to each other, and adjacent to the data bus line The tip of the fine electrode Having a notch in a portion not facing the adjacent fine electrode portion of the part be solved by a liquid crystal display device according to claim.

  Liquid crystal molecules between the fine electrode portion and the bus line are aligned in a direction different from the direction in which the fine electrode portion extends. For this reason, a dark part occurs between the fine electrode part and the bus line, which causes a substantial decrease in the aperture ratio. By reducing the distance between the fine electrode portion and the bus line, the area where the dark portion is generated can be reduced, and the substantial aperture ratio can be improved. However, in this case, the capacity between the fine electrode portion and the bus line is increased, and display quality is deteriorated due to crosstalk.

  By the way, the portion of the tip portion of the fine electrode portion that does not face the adjacent fine electrode does not contribute to aligning the liquid crystal molecules in a predetermined direction, while increasing the parasitic capacitance with the bus line. ing. Therefore, in the present invention, a notch is provided in a portion of the tip portion of the fine electrode portion that does not face the adjacent fine electrode. Thereby, the substantial aperture ratio can be improved while suppressing the occurrence of crosstalk.

FIG. 1 is a plan view showing an example of a conventional MVA mode liquid crystal display device. FIG. 2 is a diagram showing gradation luminance characteristics when viewed from the front in a conventional MVA mode liquid crystal display device and gradation luminance characteristics when viewed from the direction of an azimuth angle of 90 ° and a polar angle of 60 °. . FIG. 3 is a plan view showing the liquid crystal display device according to the first embodiment of the present invention. FIG. 4 is a schematic cross-sectional view of the liquid crystal display device of the first embodiment. FIG. 5 is a diagram illustrating transmittance-applied voltage characteristics when viewed from the front of the liquid crystal display device of the first embodiment and transmittance-applied voltage characteristics when viewed from an oblique direction. FIG. 6 is a plan view showing a liquid crystal display device according to a second embodiment of the present invention. FIG. 7 is a plan view showing a liquid crystal display device according to a third embodiment of the present invention. FIG. 8 is a plan view showing a liquid crystal display device according to a fourth embodiment of the present invention. FIG. 9 is a plan view showing a liquid crystal display device according to a fifth embodiment of the present invention. FIG. 10 is a schematic view showing the orientation of liquid crystal molecules in a conventional MVA liquid crystal display device. FIG. 11: is a top view which shows the liquid crystal display device of Example 1 of the 6th Embodiment of this invention, and its one part enlarged view. FIG. 12 is a plan view and a partially enlarged view showing a liquid crystal display device according to Example 2 of the sixth embodiment of the present invention. FIG. 13 is a plan view and a partially enlarged view showing a liquid crystal display device according to Example 3 of the sixth embodiment of the present invention. FIG. 14 is a plan view showing a liquid crystal display device according to a seventh embodiment of the present invention. FIG. 15 is a cross-sectional view taken along the line II in FIG. FIG. 16 is a diagram illustrating the relationship between the pixel capacitance ratio and the voltage ratio. FIG. 17 is a diagram illustrating transmittance characteristics and alignment characteristics in the liquid crystal display device of the seventh embodiment. FIG. 18 is a plan view showing a liquid crystal display device according to an eighth embodiment of the present invention. FIG. 19 is a diagram showing transmittance characteristics and alignment characteristics in the liquid crystal display device of the eighth embodiment. FIG. 20 is a plan view showing another example of the liquid crystal display device of the eighth embodiment. FIG. 21 is a plan view showing a liquid crystal display device according to a ninth embodiment of the present invention. FIG. 22 is a diagram showing transmittance characteristics in the liquid crystal display device of the ninth embodiment. FIGS. 23A and 23B are diagrams showing light transmission states when a voltage is applied in a liquid crystal display device (with no black matrix) in which the distance between the fine electrode portion and the data bus line is 7 μm or 5 μm. FIGS. 24A and 24B are diagrams showing light transmission states when a voltage is applied in a liquid crystal display device (with a black matrix) in which the distance between the fine electrode portion and the data bus line is 7 μm or 5 μm. FIGS. 25A and 25B are diagrams showing the results of examining the transient characteristics of the liquid crystal display device from when a voltage is applied to the liquid crystal until the alignment is stabilized using a high-speed camera. FIG. 26 is a plan view showing a liquid crystal display device according to Example 1 of the tenth embodiment. FIG. 27 is a plan view showing a liquid crystal display device according to Example 2 of the tenth embodiment. FIG. 28 is a plan view showing a liquid crystal display device according to Example 3 of the tenth embodiment. FIG. 29 is a plan view showing a liquid crystal display device according to Example 4 of the tenth embodiment. FIG. 30 is a diagram showing the relationship between the white display voltage, the directly connected pixel electrode ratio, and the gamma shift amount. FIG. 31 is a plan view showing a liquid crystal display device (part 1) according to an eleventh embodiment of the present invention. FIG. 32 is a plan view showing a liquid crystal display device (part 2) according to the eleventh embodiment of the present invention. FIG. 33 is a plan view showing a liquid crystal display device (part 3) according to the eleventh embodiment of the present invention. FIG. 34 is a plan view showing a liquid crystal display device (part 4) according to the eleventh embodiment of the present invention.

  Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings.

(First embodiment)
FIG. 3 is a plan view of the liquid crystal display device according to the first embodiment of the present invention, and FIG. 4 is a schematic cross-sectional view of the liquid crystal display device. FIG. 3 shows a region for two pixels.

  As shown in FIG. 4, the liquid crystal panel 100 includes a TFT substrate 110, a counter substrate 130, and a liquid crystal layer 140 made of liquid crystal having negative dielectric anisotropy sealed between them. Polarizing plates 141a and 141b are disposed on both sides of the liquid crystal panel 100 in the thickness direction, respectively. The liquid crystal layer 140 contains a polymer formed by polymerizing a polymerization component (monomer or oligomer) added to the liquid crystal by ultraviolet irradiation.

  As shown in FIG. 3, a plurality of gate bus lines 112 extending in the horizontal direction (X-axis direction) and a plurality of data bus lines 117 extending in the vertical direction (Y-axis direction) are formed on the TFT substrate 110. Yes. Each rectangular area defined by the gate bus line 112 and the data bus line 117 is a pixel area. In addition, an auxiliary capacitor bus line 113 is formed on the TFT substrate 110 so as to be parallel to the gate bus line 112 and cross the center of the pixel region. In the present embodiment, one of the polarizing plates 141 a and 141 b is arranged with its absorption axis parallel to the gate bus line 112, and the other is arranged with its absorption axis parallel to the data bus line 117.

  For each pixel region, a TFT 118, three subpixel electrodes 121a to 121c, control electrodes 119a and 119c, and an auxiliary capacitance electrode 119b are formed. The subpixel electrodes 121a to 121c are made of a transparent conductor such as ITO, and are provided with slits 122 that define the alignment direction of liquid crystal molecules when a voltage is applied.

  Hereinafter, the structure of the TFT substrate 110 and the counter substrate 130 will be described in more detail with reference to the plan view of FIG. 3 and the schematic cross-sectional view of FIG.

  A gate bus line 112 and an auxiliary capacitance bus line 113 are formed on a glass substrate 111 that is a base of the TFT substrate 110. The gate bus line 112 and the auxiliary capacitor bus line 113 are formed of a metal film formed by stacking, for example, Al (aluminum) -Ti (titanium).

On the gate bus line 112 and the auxiliary capacitor bus line 113, a first insulating film (gate insulating film) 114 made of, for example, SiO ₂ or SiN is formed. A semiconductor film (for example, an amorphous silicon film or a polysilicon film) 115 to be an active layer of the TFT 118 is formed in a predetermined region on the first insulating film 114. A channel protective film 116 made of SiN or the like is formed on the semiconductor film 115, and a drain electrode 118 a and a source electrode 118 b of the TFT 118 are formed on both sides of the channel protective film 116.

  On the first insulating film 114, a data bus line 117 connected to the source electrode 118b of the TFT 118, control electrodes 119a and 119c connected to the drain electrode 118a, and an auxiliary capacitance electrode 119b are formed. ing. As shown in FIG. 4, the auxiliary capacitance electrode 119b is formed at a position facing the auxiliary capacitance bus line 113 with the first insulating film 114 interposed therebetween. The auxiliary capacitance bus line 113, the auxiliary capacitance electrode 119b, and the first insulating film 114 therebetween constitute an auxiliary capacitance. The control electrodes 119a and 119c are formed along the center line of the pixel region parallel to the Y axis, and the storage capacitor electrode 119b is formed along the center line of the pixel region parallel to the X axis.

  The data bus line 117, the drain electrode 118a, the source electrode 118b, the control electrodes 119a and 119c, and the auxiliary capacitance electrode 119b are formed of, for example, a metal film formed by stacking Ti / Al / Ti.

  On the data bus line 117, the drain electrode 118a, the source electrode 118b, the control electrodes 119a and 119c, and the auxiliary capacitance electrode 119b, a second insulating film 120 made of, for example, SiN is formed. Three subpixel electrodes 121 a to 121 c are formed on the second insulating film 120. As shown in FIG. 4, the subpixel electrode 121a is capacitively coupled to the control electrode 119a via the second insulating film 120, and the subpixel electrode 121c is capacitively coupled to the control electrode 119c via the second insulating film 120. Are connected. The subpixel electrode 121b is electrically connected to the auxiliary capacitance electrode 119b through a contact hole 120a provided in the second insulating film 120.

  As shown in FIG. 3, the sub-pixel electrode 121a is disposed on the upper side of the pixel region, and is divided into two symmetrical regions (domain control regions) with a center line parallel to the Y axis as a boundary. A plurality of slits 122 extending in the direction of approximately 45 ° with respect to the X axis are formed in the right region, and a plurality of slits 122 extending in the direction of approximately 135 ° with respect to the X axis are formed in the left region. Yes.

  The sub-pixel electrode 121b is disposed at the center of the pixel region, and is divided into four regions (domain control regions) by a center line parallel to the X axis and a center line parallel to the Y axis. A plurality of slits 122 extending in a direction of approximately 45 ° with respect to the X axis are formed in the first region on the upper right, and a plurality of slits 122 extending in a direction of approximately 135 ° with respect to the X axis are formed in the second region on the upper left. A slit 122 is formed, a plurality of slits 122 extending in the direction of about 225 ° with respect to the X axis are formed in the lower left third region, and a lower right fourth region is formed with respect to the X axis. A plurality of slits 122 extending in the direction of about 315 ° are formed.

  The sub-pixel electrode 121c is disposed below the pixel region, and is divided into two symmetrical regions (domain control regions) with a center line parallel to the Y axis as a boundary. A plurality of slits 122 extending in a direction of approximately 225 ° with respect to the X axis are formed in the left region, and a plurality of slits 122 extending in a direction of approximately 315 ° with respect to the X axis are formed in the lower right region. Is formed. The width of the slit 122 of each of the subpixel electrodes 121a to 121c is, for example, 3.5 μm, and the interval between the slits (the width of the fine electrode portion) is, for example, 6 μm.

  In the specification of the present application, of the pixel electrode or the sub-pixel electrode, the band-like conductor portion between the slits is referred to as a fine electrode portion, and the portion that electrically connects the base ends of the fine electrode portion to each other is the connection electrode portion. It is called.

  A vertical alignment film (not shown) made of polyimide or the like is formed on these subpixel electrodes 121a to 121c.

  On the other hand, a black matrix (light-shielding film) 132, a color filter 133, and a common electrode 134 are formed on one surface side (lower side in FIG. 4) of the glass substrate 131 that is the base of the counter substrate 130. .

  The black matrix 132 is disposed at a position facing the gate bus line 112, the data bus line 117, and the TFT 118 on the TFT substrate 110 side. There are three types of color filters 133, red, green, and blue, and one color filter is arranged for each pixel region. One pixel is constituted by three pixels of the adjacent red pixel, green pixel, and blue pixel, and various colors can be displayed.

  The common electrode 134 is formed of a transparent conductor such as ITO and is disposed on the color filter 133 (lower side in FIG. 4). A vertical alignment film (not shown) such as polyimide is formed on the common electrode 134 (on the lower side in FIG. 4).

  In the liquid crystal display device of this embodiment configured as described above, when a display signal is applied to the data bus line 117 and a predetermined voltage (scanning signal) is applied to the gate bus line 112, the TFT 118 is turned on and the control electrode Display signals are transmitted to 119a and 119c and the auxiliary capacitance electrode 119b. Since the subpixel electrode 121b is connected to the auxiliary capacitance electrode 119b via the contact hole 120a, the voltage of the subpixel electrode 121b becomes the same as the voltage of the display signal.

On the other hand, a voltage corresponding to the capacitance value between the control electrodes 119a and 119c is applied to the subpixel electrodes 121a and 121c. Here, the voltage of the display signal is V _D , the capacitance value between the subpixel electrodes 121a and 121c and the counter electrode is C1, and the capacitance value between the subpixel electrodes 121a and 121c and the control electrodes 119a and 119c is C2. Then, the voltage V1 applied to the subpixel electrodes 121a and 121c is V1 = V _D · C2 / (C1 + C2).

  That is, a voltage lower than that of the pixel electrode 121b is applied to the subpixel electrodes 121a and 121c, and two regions having different transmittance-applied voltage characteristics (TV characteristics) exist in one pixel. Then, the total transmittance-applied voltage characteristic is obtained by combining the transmittance-applied voltage characteristics of each region. As described above, it is known that display quality deterioration when a screen is viewed obliquely is avoided by forming a plurality of regions having different transmittance-applied voltage characteristics in one pixel.

  In the present embodiment, the threshold value of the transmittance-applied voltage characteristic in the region where the sub-pixel electrode 121b (that is, the sub-pixel electrode connected to the TFT without passing through capacitive coupling: hereinafter referred to as a directly-connected pixel electrode) is arranged. And the threshold value of the transmittance-applied voltage characteristic in the region where the sub-pixel electrodes 121a and 121c (sub-pixel electrodes connected to the TFT through capacitive coupling: hereinafter referred to as capacitive-coupled pixel electrodes) are arranged Each capacitance value C1, C2 is set so that becomes 1V. In this embodiment, the ratio of the area of the region where the subpixel electrode 121b (directly connected pixel electrode) is arranged to the area of the region where the subpixel electrodes 121a and 121c (capacitive coupling pixel electrode) are arranged is 4 : 6. These capacitance values C1 and C2 and the area ratio may be set as appropriate according to desired gradation luminance characteristics.

  FIG. 5 shows the transmittance-applied voltage characteristics when viewed from the front of the liquid crystal display device of the present embodiment (Example), with the horizontal axis representing gradation and the vertical axis representing transmittance. It is a figure which shows the transmittance | permeability-applied voltage characteristic when it sees. FIG. 5 shows transmittance-applied voltage characteristics when the conventional liquid crystal display device having the structure shown in FIG. 1 is viewed from an oblique direction. As can be seen from FIG. 5, the liquid crystal display device of this embodiment has a smaller swell of the transmittance-applied voltage characteristic when viewed in an oblique direction than the liquid crystal display device of the conventional example. From this, it can be seen that the liquid crystal display device of the present embodiment has improved display quality when viewed from an oblique direction as compared with the conventional liquid crystal display device shown in FIG.

  It should be noted that in the boundary portion of each region where the extending direction of the slit 122 is different from each other, that is, the region along the center line of the pixel region parallel to the X axis and the region along the center line of the pixel region parallel to the Y axis. When applied, the liquid crystal molecules are aligned in a direction parallel to the X-axis or Y-axis (that is, a direction parallel to or orthogonal to the absorption axes of the polarizing plates 141a and 141b), and thus light is not transmitted. In this embodiment, since the control electrodes 119a and 119c and the auxiliary capacitance electrode 119b are provided at the boundary portion, the decrease in the aperture ratio due to the provision of the control electrodes 119a and 119c and the auxiliary capacitance electrode 119b is minimized. Can do.

  Hereinafter, a method for manufacturing the liquid crystal display device of the present embodiment will be described.

  First, a glass substrate 111 serving as a base for the TFT substrate 110 is prepared. Then, a metal film formed by laminating, for example, Al (aluminum) / Ti (titanium) is formed on the glass substrate 111, and the metal film is patterned by a photolithography method to form the gate bus line 112 and the auxiliary capacitor. Bus line 113 is formed. In this case, for example, the gate bus lines 112 are formed at a pitch of about 300 μm in the vertical direction.

Next, a first insulating film (gate insulating film) 114 made of an insulator such as SiO ₂ or SiN is formed on the entire upper surface of the glass substrate 111. Then, a semiconductor film (amorphous silicon film or polysilicon film) 115 serving as an active layer of the TFT 118 is formed in a predetermined region on the first insulating film 114.

  Next, a SiN film is formed on the entire upper surface of the glass substrate 111, and the SiN film is patterned by photolithography to form a channel protective film 116 on a region to be a channel of the semiconductor film 115.

  Next, an ohmic contact layer (not shown) made of a semiconductor film into which impurities are introduced at a high concentration is formed on the entire upper surface of the glass substrate 111. Thereafter, for example, a metal film formed by laminating Ti / Al / Ti, for example, in this order is formed on the glass substrate 111, and the metal film and the ohmic contact layer are patterned by a photolithography method. An electrode 118a, a source electrode 118b, control electrodes 119a and 119c, and an auxiliary capacitance electrode 119b are formed. In this case, for example, the data bus lines 117 are formed at a pitch of about 100 μm in the horizontal direction.

Next, a second insulating film 120 made of an insulator such as SiO ₂ or SiN is formed on the entire upper surface of the glass substrate 111. Then, a contact hole 120a reaching the storage capacitor electrode 119b is formed in the second insulating film 120.

  Next, ITO is sputtered on the entire upper surface of the glass substrate 111 to form an ITO film. This ITO film is electrically connected to the auxiliary capacitance electrode 119b through the contact hole 120a. Thereafter, the ITO film is patterned by a photolithography method to form subpixel electrodes 121a to 121c. As described above, the slits 122 extending in the oblique direction are formed in the sub-pixel electrodes 121a to 121c.

  Next, polyimide is applied to the entire upper surface of the glass substrate 111 to form an alignment film. In this way, the TFT substrate 110 is completed.

  Next, a method for manufacturing the counter substrate 130 will be described.

  First, a glass substrate 131 serving as a base for the counter substrate 130 is prepared. Then, a black matrix 132 is formed on a predetermined region of the glass substrate 131 with Cr (chrome) or black resin. The black matrix 132 is formed, for example, at a position facing the gate bus line 112 and the source bus line 117 on the TFT substrate 110 side.

  Next, red, green, and blue color filters 133 are formed on the glass substrate 131 using a red photosensitive resin, a green photosensitive resin, and a blue photosensitive resin.

  Next, ITO is sputtered on the entire upper surface of the glass substrate 131 to form the common electrode 134, and then polyimide is applied on the common electrode 134 to form an alignment film. In this way, the counter substrate 130 is completed.

  The TFT substrate 110 and the counter substrate 130 manufactured as described above are arranged to face each other, and a liquid crystal having a negative dielectric anisotropy is sealed between them to form a liquid crystal panel 100. For example, a polymerization component having a photofunctional group (diacrylate, methacrylate, or the like) as a polymerization component is added in advance to the liquid crystal at 0.3 wt% with respect to the liquid crystal. Further, the distance (cell gap) between the TFT substrate 110 and the counter substrate 130 is set to, for example, 3.5 to 4 μm.

  Next, a predetermined signal is applied to the gate bus line 112 to turn on the TFT 118 of each pixel, and a predetermined voltage is applied to the data bus line 117. Thereby, a voltage is applied between the subpixel electrodes 121a to 121c and the common electrode 134, and the liquid crystal molecules in the pixel are aligned in a predetermined direction. After the orientation of the liquid crystal molecules is sufficiently stabilized, the monomers in the liquid crystal are polymerized by irradiating with ultraviolet rays. The polymer formed in the liquid crystal layer in this manner determines the direction in which the liquid crystal molecules fall when a voltage is applied.

  Thereafter, polarizing plates 141a and 141b are respectively arranged on both sides in the thickness direction of the liquid crystal panel 100, and a driving circuit and a backlight are attached. In this way, the liquid crystal display device of this embodiment is completed.

(Second Embodiment)
FIG. 6 is a plan view showing a liquid crystal display device according to a second embodiment of the present invention. In FIG. 6, the same components as those in FIG. 3 are denoted by the same reference numerals, and detailed description thereof is omitted.

  In the present embodiment, two subpixel electrodes 152a and 152b are formed in one pixel region. The sub-pixel electrode 152a (directly connected pixel electrode) is disposed in the upper region in the pixel region, and is divided into four regions (domain control regions) by a center line parallel to the X axis and a center line parallel to the Y axis. ing. A plurality of slits 153 extending in a direction of approximately 45 ° with respect to the X axis are formed in the first region on the upper right, and a plurality of slits 153 extending in a direction of approximately 135 ° with respect to the X axis are formed in the second region on the upper left. A slit 153 is formed, a plurality of slits 153 extending in the direction of approximately 225 ° with respect to the X axis are formed in the lower left third region, and a lower right fourth region is formed with respect to the X axis. A plurality of slits 153 extending in the direction of about 315 ° are formed.

  The sub-pixel electrode 152b (capacitive coupling pixel electrode) is disposed in a lower region within the pixel region. The area of the subpixel electrode 152b is larger than that of the subpixel electrode 152a, and is divided into four regions (domain control regions) by a centerline parallel to the X axis and a centerline parallel to the Y axis, like the subpixel electrode 152a. Yes. A plurality of slits 153 extending in the direction of approximately 45 ° with respect to the X axis are formed in the first region on the upper right, and the second region in the upper left extends in a direction of approximately 135 ° with respect to the X axis. A plurality of slits 153 are formed, a plurality of slits 153 extending in the direction of approximately 225 ° with respect to the X axis are formed in the lower left third region, and an X axis is formed in the lower right fourth region. On the other hand, a plurality of slits 153 extending in the direction of about 315 ° are formed.

  A control electrode 151a extending along the center line of the pixel region parallel to the Y axis is formed below the subpixel electrodes 152a and 152b. The control electrode 151a is electrically connected to the drain electrode of the TFT 118.

  Further, below the subpixel electrode 152a, an auxiliary capacitance bus line 113 and an auxiliary capacitance electrode 151b are formed along the center line of the subpixel electrode 152a parallel to the X axis. The auxiliary capacity bus line 113 is formed in the same layer (layer) as the gate bus line 112. The auxiliary capacitance electrode 151b is formed in the same layer as the control electrode 151a, and is connected to the control electrode 151a. A first insulating film (corresponding to the insulating film 114 in FIG. 4) is formed between the auxiliary capacitor bus line 113 and the auxiliary capacitor electrode 151b. The first insulating film, the auxiliary capacitor bus line 113, and the auxiliary capacitor bus line 113 are provided. An auxiliary capacitor is constituted by the capacitor electrode 151b. The auxiliary capacitance electrode 151b is electrically connected to the sub-pixel electrode 152a through a contact hole 154 formed in the second insulating film (corresponding to the insulating film 120 in FIG. 4).

  Further, a control electrode 151c is formed below the subpixel electrode 152b along the center line of the subpixel electrode 152b parallel to the X axis. The control electrode 151c is also formed in the same layer as the control electrode 151a, and is electrically connected to the control electrode 151a. The control electrode 151c is capacitively coupled to the subpixel electrode 152b through the second insulating film.

  Since the structure of the counter substrate is basically the same as that of the first embodiment, the description thereof is omitted here. Also in this embodiment, a liquid crystal to which a polymerization component such as diacrylate is added is sealed between the TFT substrate and the counter substrate, and a voltage is applied between the pixel electrode (sub-pixel electrodes 152a and 152b) and the common electrode. Is applied to align the liquid crystal molecules in a predetermined direction, and then irradiated with ultraviolet rays to polymerize the polymerization components, thereby forming a polymer in the liquid crystal layer.

  Also in this embodiment, since two regions having different transmittance-applied voltage characteristics are provided in one pixel as in the first embodiment, deterioration in display quality when the screen is viewed from an oblique direction is avoided. The effect that it is done.

  In the present embodiment, the auxiliary capacitance bus line 113 and the auxiliary capacitance electrode 151b are formed along the center line of the sub-pixel electrode 152a parallel to the X axis. This portion is a domain boundary, and liquid crystal molecules are tilted in a direction parallel to the X axis when a voltage is applied. Therefore, even if there is no auxiliary capacitance bus line 113 and auxiliary capacitance electrode 151b, light is transmitted through this portion. do not do. Therefore, a decrease in transmittance due to the formation of the auxiliary capacitance bus line 113 and the auxiliary capacitance electrode 151b is avoided. In the present embodiment, it is possible to adjust the capacitance value of the auxiliary capacitance by adjusting the length and width of the auxiliary capacitance electrode 151b, and there is an advantage that the design flexibility of the capacitance value of the auxiliary capacitance is high. is there.

  Similarly, since the control electrode 151c is formed along the center line of the sub-pixel electrode 152b parallel to the X axis, a decrease in transmittance due to the formation of the control electrode 151c is avoided. Further, by adjusting the length and width of the control electrode 151c, it is possible to adjust the coupling capacitance value between the control electrodes 151a and 151c and the sub-pixel electrode 152b. There is also an advantage of high.

(Third embodiment)
FIG. 7 is a plan view showing a liquid crystal display device according to a third embodiment of the present invention. 7, the same components as those in FIG. 3 are denoted by the same reference numerals, and detailed description thereof is omitted.

  Also in this embodiment, two subpixel electrodes 162a and 162b are formed in one pixel region. The sub-pixel electrode 162a (directly connected pixel electrode) is disposed in the upper region in the pixel region, and is divided into four regions (domain control regions) by a center line parallel to the X axis and a center line parallel to the Y axis. ing. A plurality of slits 163 extending in a direction of approximately 45 ° with respect to the X axis are formed in the first region on the upper right, and a plurality of slits 163 extending in a direction of approximately 135 ° with respect to the X axis are formed in the second region on the upper left. A slit 163 is formed, a plurality of slits 163 extending in the direction of about 225 ° with respect to the X axis are formed in the lower left third region, and a lower right fourth region is formed with respect to the X axis. A plurality of slits 163 extending in the direction of about 315 ° are formed.

  The sub-pixel electrode 162b (capacitive coupling pixel electrode) is disposed in the lower region within the pixel region. The area of the subpixel electrode 162b is larger than that of the subpixel electrode 162a, and is divided into four regions (domain control regions) by a centerline parallel to the X axis and a centerline parallel to the Y axis, like the subpixel electrode 162a. Yes. A plurality of slits 163 extending in the direction of approximately 315 ° with respect to the X axis are formed in the first region on the upper right, and the second region in the upper left extends in a direction of approximately 225 ° with respect to the X axis. A plurality of slits 163 are formed, a plurality of slits 163 extending in a direction of approximately 135 ° with respect to the X axis are formed in the lower left third region, and an X axis is formed in the lower right fourth region. On the other hand, a plurality of slits 163 extending in a direction of approximately 45 ° are formed.

  A control electrode 161a is formed below the sub-pixel electrodes 162a and 162b along the center line of the pixel region parallel to the Y axis. The control electrode 161a is electrically connected to the drain electrode 118a of the TFT 118.

  In addition, below the subpixel electrode 162a, an auxiliary capacitance bus line 113 and an auxiliary capacitance electrode 161b are formed along the center line of the subpixel electrode 162a parallel to the X axis. The auxiliary capacity bus line 113 is formed in the same layer as the gate bus line 112. The auxiliary capacitance electrode 161b is formed in the same layer as the control electrode 161a, and is electrically connected to the control electrode 161a. A first insulating film (corresponding to the insulating film 114 in FIG. 4) is formed between the auxiliary capacitance bus line 113 and the auxiliary capacitance electrode 161b, and the auxiliary capacitance bus line 113, the auxiliary capacitance electrode 161b, and between them. The first insulating film constitutes an auxiliary capacitor. The auxiliary capacitance electrode 161b is electrically connected to the sub-pixel electrode 162a through a contact hole 164 formed in the second insulating film (corresponding to the insulating film 120 in FIG. 4).

  Further, a control electrode 161c is formed below the end of the subpixel electrode 162b. The control electrode 161c is also formed in the same layer as the control electrode 161a and is electrically connected to the control electrode 161a. The control electrode 161c is capacitively coupled to the subpixel electrode 162b through the second insulating film.

  Also in this embodiment, since the structure of the counter substrate is basically the same as that of the first embodiment, the description of the counter substrate is omitted here. Also in this embodiment, a liquid crystal to which a polymerization component such as diacrylate is added is sealed between the TFT substrate and the counter substrate, and a voltage is applied between the pixel electrode (sub-pixel electrodes 162a and 162b) and the common electrode. Is applied to orient the liquid crystal molecules in a predetermined direction, and then the ultraviolet ray is irradiated to polymerize the polymerization component.

  In the second embodiment described above (see FIG. 6), the liquid crystal molecules between the subpixel electrode 152a and the subpixel electrode 152b are tilted in the direction parallel to the X axis when a voltage is applied. A dark line is generated between the pixel electrode 152b and the pixel electrode 152b. On the other hand, in this embodiment, since the gap between the two subpixel electrodes 162a and 162b extends in the same direction as the slit 163 in the vicinity thereof, the liquid crystal molecules between the subpixel electrodes 162a and 162b are slit when a voltage is applied. Inclined in the same direction as 163. Thereby, no dark line is generated between the sub-pixel electrodes 162a and 162b, and the substantial aperture ratio is improved.

  Also in this embodiment, two regions having different transmittance-applied voltage characteristics are provided in one pixel as in the first embodiment, so that the display quality deteriorates when the screen is viewed from an oblique direction. The effect is to be avoided.

(Fourth embodiment)
FIG. 8 is a plan view showing a liquid crystal display device according to a fourth embodiment of the present invention.

  In this embodiment, as shown in FIG. 8, the data bus line 177 is formed in a zigzag shape bent in a direction of approximately 45 ° or 315 ° with respect to the X axis. However, the gate bus line 122 is formed in parallel to the X-axis as in the first to third embodiments.

  Three subpixel electrodes 172a, 172b, and 172c and a TFT 118 are formed for each pixel region defined by the gate bus line 122 and the data bus line 177. Also in this embodiment, the TFT 118 uses a part of the gate bus line 122 as a gate electrode, and the drain electrode 118b and the source electrode 118a are arranged to face each other with the gate bus line 122 interposed therebetween. A control electrode 171 having a shape bent along the center line of the pixel region is formed below the sub-pixel electrodes 172a to 172c. The control electrode 171 is formed on the first insulating film (corresponding to the insulating film 114 in FIG. 3), and is electrically connected to the drain electrode 118b of the TFT 118.

  The sub-pixel electrode 172a (capacitive coupling pixel electrode) is divided into two regions (domain control regions) by the center line. A slit 173 extending in the direction of approximately 315 ° with respect to the X axis is provided in the right region, and a slit 173 extending in the direction of approximately 135 ° with respect to the X axis is provided in the left region.

  The sub-pixel electrode 172b (directly connected pixel electrode) is disposed in the bent portion at the center of the pixel region, and includes a first region in which a slit 173 extending in a direction of approximately 45 ° with respect to the X-axis is formed, and the X-axis With respect to the X axis, a second region in which the slit 173 is formed, a third region in which the slit 173 is extended in the direction of approximately 225 ° with respect to the X axis, and a 315 with respect to the X axis. It is divided into a fourth region in which a slit 173 extending in the direction of ° is formed. The sub-pixel electrode 172b is electrically connected to the control electrode 171 through a contact hole 174 provided in a second insulating film (corresponding to the insulating film 120 in FIG. 3).

  The sub-pixel electrode 172c (capacitive coupling pixel electrode) is divided into two regions (domain control regions) by the center line. A slit 173 extending in the direction of approximately 45 ° with respect to the X axis is provided in the right region, and a slit 173 extending in the direction of approximately 225 ° with respect to the X axis is provided in the left region. The subpixel electrodes 172a and 172c are capacitively coupled to the control electrode 171 through the second insulating film.

  Also in this embodiment, since the structure of the counter substrate is basically the same as that of the first embodiment, the description of the counter substrate is omitted here. Also in this embodiment, a liquid crystal added with a polymerization component such as diacrylate is sealed between the TFT substrate and the counter substrate, and a voltage is applied between the pixel electrodes (sub-pixel electrodes 172a to 172c) and the common electrode. Is applied to orient the liquid crystal molecules in a predetermined direction, and then the ultraviolet ray is irradiated to polymerize the polymerization component.

  In the first to third embodiments, the slit of the subpixel electrode extends in the directions of 45 °, 135 °, 225 °, and 315 ° with respect to the X axis, and the liquid crystal molecules are inclined in the same direction as the slit. However, since electric lines of force are generated outward at the end of the subpixel electrode, the liquid crystal molecules between the subpixel electrode and the data bus line are tilted in a direction parallel to the X axis. On the other hand, one of the two polarizing plates sandwiching the liquid crystal panel is arranged with the absorption axis parallel to the X axis, and the other is arranged with the absorption axis parallel to the Y axis. In this case, in the liquid crystal display devices of the first to third embodiments, a dark portion is generated between the subpixel electrode and the data bus line, and the substantial aperture ratio is reduced.

  Therefore, in the present embodiment, as shown in FIG. 8, the data bus line 177 extends in the direction of approximately 45 ° or 315 ° with respect to the gate bus line 122 in advance, and the subpixel electrodes 172a to 172c The liquid crystal molecules between the data bus line 177 and the polarization axis of the polarizing plate are inclined in a direction of 45 °. Accordingly, no dark portion is generated between the sub-pixel electrodes 172a to 172c and the data bus line 177, the substantial aperture ratio is improved as compared with the first to third embodiments, and a brighter display is possible. The effect of becoming. When the liquid crystal display device according to the present embodiment was actually manufactured and its transmittance was examined, the transmittance was improved by about 5% as compared with the liquid crystal display device having the structure shown in FIG.

  Also in the liquid crystal display device of this embodiment, since a plurality of regions having different transmittance-applied voltage characteristics are formed in one pixel, an effect of improving display quality when the screen is viewed from an oblique direction is obtained. It is done.

(Fifth embodiment)
FIG. 9 is a plan view showing a liquid crystal display device according to a fifth embodiment of the present invention. This embodiment is different from the fourth embodiment in that the shape of the subpixel electrode is different, and the other structure is the same as that of the fourth embodiment. A detailed description thereof is omitted with reference numerals.

  In the liquid crystal display device of the fourth embodiment shown in FIG. 8, many slits 173 are formed in the subpixel electrodes 172a to 172c. These slits 173 are formed by a photolithography method. That is, a photoresist is applied on the ITO film to be the subpixel electrodes 172a to 172c, followed by stepper exposure, development processing, and etching of the ITO film using the remaining photoresist film as a mask. However, since the slit 173 is fine, the slit width varies due to variations in the film thickness of the photoresist film and a slight difference in exposure amount (shot unevenness) during stepper exposure, which affects the optical characteristics. It is conceivable that the display quality deteriorates.

  Therefore, in the fifth embodiment, the slits 183 are formed only at the ends and the bent portions of the subpixel electrodes 182a to 182c (corresponding to the subpixel electrodes 172a to 172c of the fourth embodiment). In the liquid crystal display device of this embodiment, when polymerizing a polymerization component (monomer) added to the liquid crystal, a voltage is applied compared to the liquid crystal display device of the fourth embodiment, and the liquid crystal molecules are in a predetermined direction. The time until orientation is increased. However, since the orientation direction of the liquid crystal molecules is determined by the polymer in the liquid crystal layer in actual use, response characteristics equivalent to those of the liquid crystal display device of the fourth embodiment can be obtained.

(Sixth embodiment)
The sixth embodiment of the present invention will be described below.

  As described above, in the liquid crystal display device shown in FIG. 1, the slit width varies due to the photolithography process, and a tile-shaped pattern may be seen when halftone display is performed. The inventors of the present application conducted various experiments and studies to solve such problems. As a result, when the thickness (cell gap) of the liquid crystal layer is d, the width of the conductor portion (that is, the fine electrode portion) between the slits is L, and the slit width is S, the following equation (1) is satisfied. The inventors have found that by setting the values of d, L, and S, display unevenness due to the photolithography process can be prevented.

L + d−S ≧ 4 μm (1)
For example, the thickness d of the liquid crystal layer may be 4 μm, the width L of the fine electrode portion may be 6 μm, and the slit width S may be 3.5 μm.

  When a liquid crystal display device was actually manufactured under the above conditions, it was confirmed that generation of tile-shaped patterns could be prevented. However, there is a new problem that the luminance at the time of white display is lowered. This is considered to be due to the following reasons.

  When a voltage is applied between the pixel electrode and the common electrode, liquid crystal molecules (liquid crystal molecules having negative dielectric anisotropy) tend to fall in a direction perpendicular to the lines of electric force generated from the pixel electrodes. As shown in FIG. 10, the liquid crystal molecules 203 on the tip end side (data bus line 202 side) of the fine electrode portion 201 are tilted toward the center of the pixel simultaneously with the voltage application. In addition, on the slit 204 and the fine electrode portion 201, the liquid crystal molecules 203 that try to fall in opposite directions collide with each other, and finally, under the influence of the liquid crystal molecules 203 at the tip portion of the fine electrode portion 201, these The liquid crystal molecules 203 fall in the direction in which the slit 204 extends.

  However, since the liquid crystal molecules 203 between the tip of the fine electrode part 201 and the data bus line 202 are tilted in a direction substantially perpendicular to the data bus line 202 when a voltage is applied, a dark part is generated in this part. When the width of the fine electrode part 201 is wide (for example, 6 μm), the area that becomes a dark part increases, and thus the luminance decreases.

  In order to reduce the dark area, it is conceivable to extend the fine electrode part 201 to reduce the distance between the fine electrode part 201 and the data bus line 202. However, simply reducing the distance between the fine electrode portion 201 and the data bus line 202 increases the parasitic capacitance between the fine electrode portion 201 and the data bus line 202, causing crosstalk and degrading display quality. Will be invited. That is, there is a trade-off relationship between improvement of luminance and suppression of crosstalk.

  The inventors of the present application observed in detail the alignment state of liquid crystal molecules in a liquid crystal display device having a pixel electrode having the shape shown in FIG. As a result, the liquid crystal molecules 203 are tilted almost perpendicularly to the data bus line 202 in the portion (the portion indicated by A in FIG. 10) where there is no opposing fine electrode portion 201 in the tip portion of the fine electrode portion 201. found. Since the tip portion of the fine electrode portion 203 is close to the data bus line 202, it causes a parasitic capacitance to increase.

  Therefore, in the present embodiment, as shown in FIG. 11, the distance between the fine electrode portion 215b and the data bus line 212 is reduced, and the liquid crystal molecules are arranged in the direction of the slit 215a at the tip portion of the fine electrode portion 215b. A notch is provided in a portion that does not contribute to orientation, that is, a portion that does not have an opposing fine electrode portion (a portion surrounded by a circle in FIG. 11), thereby avoiding an increase in parasitic capacitance. Thereby, the transmittance at the time of white display is improved, power saving is possible, and deterioration of display quality is avoided.

  In FIG. 11, 211 denotes a gate bus line, 212 denotes a data bus line, 214 denotes a TFT, and 215 denotes a pixel electrode. Also, the alternate long and short dash line in the enlarged view of FIG. 11 indicates the tip position of the fine electrode portion in the conventional MVA mode liquid crystal display device.

  It is extremely difficult to form a fine electrode portion with a sharp tip at the photolithography process, and usually the tip of the fine electrode portion is rounded. Moreover, a slight change in conditions in the photolithography process causes variations in roundness, which causes variations in optical characteristics. For this reason, at the time of designing, it is preferable that the tip shape of the fine electrode portion is an arc shape or a polygonal shape with a predetermined curvature.

  Further, the inventors of the present application further observed the alignment state of the liquid crystal molecules in the liquid crystal display device having the pixel electrode having the shape shown in FIG. 10, and as a result, the vicinity of the base end portion (the portion indicated by B in FIG. 10) of the slit 204. Then, it has been found that the liquid crystal molecules 203 do not tilt in the 45 ° direction, which is a factor of decreasing white luminance. This is considered to be due to the following reason.

  The trunk portion of the pixel electrode (the portion connecting the fine electrode portions to each other: the connection electrode 205) is formed in parallel to the gate bus line 202. The liquid crystal molecules 203 in the region B sandwiched between the connection electrode 205 and the fine electrode part 201 collide with each other in an attempt to fall in a direction orthogonal to the lines of electric force generated from the connection electrode 205 and the fine electrode part 201, and finally. Falls in the direction in which both are balanced, that is, in the direction of a line that bisects the angle formed by the connection electrode 205 and the fine electrode portion 201. Since this direction deviates from the direction in which the slit 204 extends, the transmittance during white display is low.

  Therefore, in the present embodiment, the shape of the base end portion of the slit is a shape that is line symmetric with respect to the center line of the slit. Specifically, for example, as shown in FIG. 12, the shape of the base end side of the slit 215a is a rectangular shape, or isosceles triangle is shown in FIG. As a result, the liquid crystal molecules 203 at the base end of the slit 215a are tilted in the direction of the center line of the slit 215a, and the luminance is improved.

  Hereinafter, the result of actually manufacturing the liquid crystal display device of this embodiment and examining the characteristics thereof will be described in comparison with a comparative example. In the liquid crystal display devices of these examples and comparative examples, the structure of the counter substrate is the same as that of the liquid crystal display device of the first embodiment. In addition, a liquid crystal added with diacrylate (liquid crystal with negative dielectric anisotropy) was sealed between the TFT substrate and the counter substrate, and then a predetermined voltage was applied between the pixel electrode and the common electrode. In this state, ultraviolet rays are irradiated to form a polymer in the liquid crystal layer. In addition, polarizing plates are arranged on both sides of the liquid crystal panel.

(Comparative Example 1)
A liquid crystal display device having a pixel electrode as shown in FIG. 1 was manufactured. The thickness d of the liquid crystal layer of the liquid crystal display device of Comparative Example 1 is 3.8 μm, the width L of the fine electrode portion is 3 μm, and the slit width S is 3.5 μm. The value of L + d−S is 3.3 μm, which does not satisfy the above-described formula (1). When halftone display was performed on the entire surface of the liquid crystal display device of Comparative Example 1, a tile-shaped pattern was observed.

(Comparative Example 2)
A liquid crystal display device having a pixel electrode as shown in FIG. 1 was manufactured. In the liquid crystal display device of Comparative Example 2, the thickness d of the liquid crystal layer is 4 μm, the width L of the fine electrode portion is 3 μm, and the slit width S is 3.5 μm. The value of L + d−S is 3.5 μm, which does not satisfy the above-described formula (1). When intermediate gradation display was performed on the entire surface of the liquid crystal display device of Comparative Example 2, a tile-shaped pattern was observed.

(Comparative Example 3)
A liquid crystal display device having a pixel electrode as shown in FIG. 1 was manufactured. In the liquid crystal display device of Comparative Example 3, the thickness d of the liquid crystal layer is 4 μm, the width L of the fine electrode portion is 6 μm, and the slit width S is 3.5 μm. The value of L + d−S is 6.5 μm, which satisfies the above-described expression (1). When intermediate gradation display was performed on the entire surface of the liquid crystal display device of Comparative Example 3, no tile-shaped pattern was observed. However, when the luminance of the liquid crystal display device during white display was measured, it was found that the liquid crystal display device was about 10% lower than the liquid crystal display device of Comparative Example 2.

Example 1
A liquid crystal display device having pixel electrodes as shown in FIG. 11 was manufactured. In the liquid crystal display device of Example 1, the thickness d of the liquid crystal layer is 4 μm, the width L of the fine electrode portion is 6 μm, and the slit width S is 3 μm. The value of L + d−S is 7 μm, which satisfies the above-described formula (1). When intermediate gradation display was performed on the entire surface of the liquid crystal display device of Example 1, no tile-shaped pattern was observed. Further, when the luminance of this liquid crystal display device during white display was measured, it was found that the liquid crystal display device was improved by about 7% as compared with the liquid crystal display device of Comparative Example 3.

(Example 2)
A liquid crystal display device having pixel electrodes as shown in FIG. 12 was manufactured. The thickness d of the liquid crystal layer of the liquid crystal display device of Example 2 is 4 μm, the width L of the fine electrode portion is 6 μm, and the slit width S is 3 μm. The value of L + d−S is 7 μm, which satisfies the above-described formula (1). When intermediate gradation display was performed on the entire surface of the liquid crystal display device of Example 2, no tile-shaped pattern was observed. Further, when the luminance of the liquid crystal display device during white display was measured, it was found that the liquid crystal display device was improved by about 7.1% as compared with the liquid crystal display device of Comparative Example 3.

(Example 3)
A liquid crystal display device having a pixel electrode as shown in FIG. 13 was manufactured. The thickness d of the liquid crystal layer of the liquid crystal display device of Example 3 is 4 μm, the width L of the fine electrode portion is 6 μm, and the slit width S is 3 μm. The value of L + d−S is 7 μm, which satisfies the above-described formula (1). When intermediate gradation display was performed on the entire surface of the liquid crystal display device of Example 3, no tile pattern was observed. Further, when the luminance of the liquid crystal display device during white display was measured, it was found that the liquid crystal display device was improved by about 7.1% as compared with the liquid crystal display device of Comparative Example 3.

  By comparing these Examples 1 to 3 and Comparative Examples 1 to 3, the liquid crystal display device of this embodiment is effective in improving display quality, and has high transmittance during white display and effective in power saving. It was confirmed that there was.

(Seventh embodiment)
The seventh embodiment of the present invention will be described below.

  In the liquid crystal display device of the first embodiment, the aperture ratio can be increased because there are no structures such as protrusions and wide slits. However, if the auxiliary capacity is not sufficiently increased with respect to the pixel capacity, the voltage applied to the liquid crystal is greatly reduced within one frame period (about 16.7 ms), and the transmission intensity is saturated before the peak. This is a phenomenon called a two-stage response. If the transmission intensity is saturated at 90% or less due to the two-stage response, the response speed of the liquid crystal panel cannot be shortened even if the liquid crystal rises sharply. Therefore, in the present embodiment, the capacity value of the auxiliary capacitor is increased while maintaining the aperture ratio, and the above problem is solved. Hereinafter, a specific description will be given with reference to FIGS. 14 and 15.

  FIG. 14 is a plan view showing one pixel of a liquid crystal display device according to a seventh embodiment of the present invention, and FIG. 15 is a cross-sectional view taken along the line II in FIG. In FIG. 14, the polarizing plate is not shown.

  As shown in FIG. 14, a plurality of gate bus lines 312 extending in the horizontal direction (X-axis direction) and a plurality of data bus lines 317 extending in the vertical direction (Y-axis direction) are formed on the TFT substrate 310. Yes. A storage capacitor bus line 313 is formed in parallel with the gate bus line 312 at the center of the rectangular pixel area defined by the gate bus line 312 and the data bus line 317.

  In addition, auxiliary capacitance lower electrodes 313a and 313c, TFT 318, auxiliary capacitance electrode 319b, control electrodes 319a and 319c, and first to third subpixel electrodes 321a to 321c are formed for each pixel region. The auxiliary capacitance lower electrodes 313a and 313c are formed along the center line of the pixel region parallel to the Y axis, and are electrically connected to the auxiliary capacitance bus line 313.

  The TFT 318 uses a part of the gate bus line 312 as a gate electrode, and a drain electrode 318a and a source electrode 318b are arranged to face each other with the gate bus line 312 interposed therebetween.

  The control electrodes 319a and 319c are formed at positions facing the storage capacitor lower electrodes 313a and 313c with the first insulating film 314 interposed therebetween, and are electrically connected to the drain electrode 318a. The auxiliary capacitance electrode 319b is formed at a position facing the auxiliary capacitance bus line 313 with the first insulating film 314 interposed therebetween, and is electrically connected to the control electrodes 319a and 319c. The auxiliary capacitance bus line 313 and the auxiliary capacitance lower electrodes 313a and 313c, the auxiliary capacitance electrode 319b, the control electrodes 319a and 319c, and the first insulating film 314 therebetween constitute an auxiliary capacitance.

  The subpixel electrodes 321 a to 321 c are formed of a transparent conductor such as ITO, and are disposed on the second insulating film 320 along the data bus line 317. As shown in FIG. 14, the sub-pixel electrode 321a (capacitive coupling pixel electrode) is arranged in the upper region of the pixel region, and is divided into two regions (domain control regions) with a center line parallel to the Y axis as a boundary. Has been. A slit 322 extending in the direction of 45 ° with respect to the X axis is formed in the right region, and a slit 322 extending in the direction of 135 ° with respect to the Y axis is formed in the left region. The subpixel electrode 321a is capacitively coupled to the control electrode 319a through the second insulating film 320.

  The sub-pixel electrode 321b (directly connected pixel electrode) is disposed at the center of the pixel region, and is divided into four regions (domain control regions) with a center line parallel to the X axis and a center line parallel to the Y axis as boundaries. ing. A slit 322 extending in the direction of 45 ° with respect to the X axis is formed in the upper right region, and a slit 322 extending in the direction of 135 ° with respect to the X axis is formed in the upper left region. A slit 322 extending in the direction of 225 ° with respect to the X axis is formed in the region, and a slit 322 extending in the direction of 315 ° with respect to the X axis is formed in the lower right region. The subpixel electrode 321b is electrically connected to the auxiliary capacitance electrode 319b through the contact hole 320a.

  The sub-pixel electrode 321c (capacitive coupling pixel electrode) is disposed in a lower region of the pixel region, and is divided into two regions (domain control regions) with a center line parallel to the Y axis as a boundary. A slit 322 extending in the direction of 315 ° with respect to the X axis is formed in the right region, and a slit 322 extending in the direction of 225 ° with respect to the X axis is formed in the left region. The subpixel electrode 319c is capacitively coupled to the control electrode 319c through the second insulating film 320.

  Hereinafter, the structure of the TFT substrate 310 and the counter substrate 330 will be described in more detail with reference to the plan view of FIG. 14 and the cross-sectional view of FIG.

  A gate bus line 312, an auxiliary capacitance bus line 313, and auxiliary capacitance lower electrodes 313 a and 313 c are formed on a glass substrate 311 which is a base of the TFT substrate 310. The gate bus line 312, the auxiliary capacitance bus line 313, and the auxiliary capacitance lower electrodes 313 a and 313 c are simultaneously formed by patterning, for example, a metal film formed by laminating Al—Ti by photolithography.

A first insulating film (gate insulating film) 314 made of SiO ₂ or SiN is formed on the gate bus line 312, the auxiliary capacitor bus line 313, and the auxiliary capacitor lower electrodes 313 a and 313 c. In a predetermined region of the first insulating film 314, a semiconductor film (amorphous silicon or polysilicon film) 315 serving as an active layer of the TFT 318 is formed. A channel protective film 316 made of SiN or the like is formed on the semiconductor film 315, and a drain electrode 318a and a source electrode 318b of the TFT 318 are formed on both sides of the channel protective film 316.

  In addition, on the first insulating film 314, a data bus line 317 connected to the source electrode 318b of the TFT 318, control electrodes 319a and 319c connected to the drain electrode 318a, and an auxiliary capacitance electrode 319b are formed. ing. As shown in FIG. 15, the auxiliary capacitance electrode 319b is formed at a position facing the auxiliary capacitance bus line 313 with the first insulating film 314 interposed therebetween. The control electrode 319a is formed at a position facing the auxiliary capacitance lower electrode 313a with the first insulating film 314 interposed therebetween, and the control electrode 319c is opposed to the auxiliary capacitance lower electrode 313c with the first insulating film 314 interposed therebetween. Formed in position.

  The data bus line 317, the drain electrode 318a, the source electrode 318b, the control electrodes 319a and 319c, and the auxiliary capacitance electrode 319b are simultaneously formed by patterning a metal film formed by stacking, for example, Ti / Al / Ti by photolithography. It is formed.

  A second insulating film 320 made of, for example, SiN is formed on the data bus line 317, the drain electrode 318a, the source electrode 318b, the control electrode 319a, and the auxiliary capacitance electrode 319b. Subpixel electrodes 321 a to 321 c are formed on the second insulating film 320. As described above, the sub-pixel electrodes 321a to 321c are each provided with the slit 322 extending in an oblique direction with respect to the X axis. In this embodiment, the width of each slit 322 provided in the subpixel electrodes 321a to 321c is 3.5 μm, and the width of the conductor portion (fine electrode portion) between the slits 322 is 6 μm.

  The subpixel electrode 321a is capacitively coupled to the control electrode 319a via the second insulating film 320, and the subpixel electrode 321b is connected to the auxiliary capacitance electrode 319b via the contact hole 320a formed in the second insulating film 320. The sub-pixel electrode 321c is capacitively coupled to the control electrode 319c through the second insulating film 320.

  A vertical alignment film (not shown) made of polyimide or the like is formed on the control electrodes 319a to 319c.

  On the other hand, a black matrix 332, a color filter 333, and a common electrode 334 are formed on the glass substrate 331 that is the base of the counter substrate 330 (on the lower side in FIG. 15).

  The black matrix 332 is made of, for example, a metal such as Cr or black resin, and is disposed at a position facing the gate bus line 312, the data bus line 317, the auxiliary capacitance bus line 313, and the TFT 318 on the TFT substrate 310 side. There are three types of color filters 333, red, green, and blue, and one color filter is arranged for each pixel region.

  The common electrode 334 is made of a transparent conductor such as ITO and is disposed on the color filter 333 (lower side in FIG. 15). A vertical alignment film (not shown) made of polyimide or the like is formed on the common electrode 334 (on the lower side in FIG. 15).

  Between the TFT substrate 310 and the counter substrate 330, a liquid crystal layer 340 made of liquid crystal having negative dielectric anisotropy sealed between the substrates 310 and 330 is disposed. In the liquid crystal layer 340, a polymer that determines the alignment direction of liquid crystal molecules when a voltage is applied is formed. This polymer is formed by polymerizing a polymerization component (a monomer such as diacrylate) added to the liquid crystal by irradiating ultraviolet rays with a voltage applied between the sub-pixel electrodes 321a to 321c and the common electrode 334. It has been done.

  In the present embodiment, a liquid crystal having a negative dielectric anisotropy is used. When a liquid crystal having a positive dielectric anisotropy is used, liquid crystal molecules are aligned parallel to the substrate surface when no voltage is applied, so that the applied voltage cannot be increased when the polymerization components are polymerized. For this reason, it becomes difficult to make the alignment direction of the liquid crystal molecules the direction in which the slit extends.

  In the present embodiment, since the storage capacitor lower electrodes 313a and 313c and the control electrodes 319a and 319c are arranged at the boundary portions of the domain control regions where the alignment directions of the liquid crystal molecules are different from each other, that is, the portions where light is not transmitted. The auxiliary capacity can be increased without reducing the aperture ratio. Conversely, the width of the auxiliary capacitor bus line 313 and the auxiliary capacitor electrode 319b may be reduced by an amount corresponding to the capacitance formed by the auxiliary capacitor lower electrodes 313a and 313c and the control electrodes 319a and 319c. The aperture ratio can be increased while securing the capacitance value.

  FIG. 16 is a diagram illustrating the relationship between the horizontal axis representing the pixel capacitance ratio (ratio between auxiliary capacitance and pixel capacitance) and the vertical axis representing the voltage ratio. However, here, the thickness (cell gap) of the liquid crystal layer is 4 μm, the thickness of the first insulating film between the auxiliary capacitance bus line and the auxiliary capacitance lower electrode, the auxiliary capacitance electrode and the control electrode is 0.33 μm, The amount of change in dielectric constant Δε of the liquid crystal is −3.5, and the aperture ratio is 53%. The voltage ratio is the ratio between the writing voltage in white display and the voltage applied to the liquid crystal layer, and the writing voltage in white display is 1.

  In this case, the auxiliary capacitance of the liquid crystal display device of the first embodiment shown in FIG. 3 is 1.5 in terms of the pixel capacitance ratio. On the other hand, the auxiliary capacity of the liquid crystal display device of this embodiment is 2.5 in terms of the pixel capacity ratio. When the difference in the pixel capacitance ratio is converted into the voltage ratio applied to the liquid crystal, it is 0.92 in the liquid crystal display device of the first embodiment and 0.94 in the liquid crystal display device of the present embodiment. It has been found that when the voltage ratio is smaller than the voltage ratio at which the transmission intensity is 90%, the response speed of the liquid crystal panel does not increase even when the rise of the liquid crystal molecules is steep. The voltage at which the transmission intensity is 90% affects not only the optical characteristics of the liquid crystal but also the alignment uniformity of the liquid crystal molecules. In both the first embodiment and the liquid crystal display device of the present embodiment, the voltage ratio at which the transmission intensity was 90% was 0.93. From these, it can be seen that the liquid crystal display device of this embodiment has good response characteristics.

  The liquid crystal display device of the first embodiment and the liquid crystal display device of the present embodiment were actually manufactured, and the response speed was measured. That is, the response speed defined by the sum of the rise time (τr) from 10% to 90% and the fall time (τf) from 90% to 10% was measured. As a result, it was confirmed that the response speed of the liquid crystal display device of the first embodiment was 20 ms, whereas the response speed of the liquid crystal display device of the present embodiment was as short as 12 ms.

(Eighth embodiment)
The eighth embodiment of the present invention will be described below.

  In the liquid crystal display device of the seventh embodiment, different voltages are applied to the subpixel electrode 321b directly connected to the TFT 318 and the subpixel electrodes 321a and 321c connected to the TFT 318 through capacitive coupling. A potential difference is generated between the subpixel electrode 321b and the subpixel electrodes 321a and 321c. Due to this potential difference, the alignment direction of the liquid crystal molecules between the sub-pixel electrode 321b and the sub-pixel electrodes 321a and 321c is shifted from the direction in which the slit 322 extends. Such a phenomenon is called azimuth fluctuation (or φ fluctuation). When azimuth blurring occurs, the birefringence of the liquid crystal locally decreases, dark lines are generated, and the light transmittance decreases.

  FIG. 17 is a diagram illustrating transmittance characteristics and alignment characteristics in the liquid crystal display device of the seventh embodiment. 17 in FIG. 17 indicates an auxiliary capacitor lower electrode (corresponding to the auxiliary capacitor lower electrodes 313a and 313c in FIG. 14), 4 indicates a control electrode (corresponding to the control electrodes 319a and 319c in FIG. 14), and 1 indicates a TFT. Directly connected subpixel electrodes (corresponding to the subpixel electrode 321b in FIG. 14) are shown. Reference numeral 3 denotes subpixel electrodes capacitively coupled to the control electrode 4 (corresponding to the subpixel electrodes 321a and 321c in FIG. 14).

  As shown in FIG. 17, since a potential difference is generated between the subpixel electrodes 1 and 3, a phenomenon (azimuth fluctuation) occurs in which the alignment direction of the liquid crystal molecules deviates from the direction in which the slit extends. Then, the portion where the azimuth angle blur has occurred becomes a dark line due to a decrease in the birefringence of the liquid crystal. In the liquid crystal display device of the seventh embodiment, as indicated by 9 in FIG. 17, both sides of the fine electrode portion (the fine electrode portion closest to the subpixel electrode 1) at the edge of the subpixel electrode 3 (right side of FIG. 17). A dark line is generated in each portion surrounded by a broken line in the figure.

  Therefore, in the present embodiment, the generation of dark lines between the subpixel electrode directly connected to the TFT and the subpixel electrode connected to the TFT through capacitive coupling is suppressed, thereby realizing a substantial improvement in the aperture ratio. Hereinafter, a specific description will be given with reference to FIG.

  FIG. 18 is a plan view showing one pixel of the liquid crystal display device according to the eighth embodiment of the present invention. In FIG. 18, the same components as those in FIG. 14 are denoted by the same reference numerals, and description of overlapping portions is omitted.

  In the present embodiment, the auxiliary capacitance lower electrode 341 and the control electrode 345 are provided below the region between the subpixel electrode 321b directly connected to the TFT 318 and the subpixel electrodes 321a and 321c capacitively coupled to the control electrodes 319a and 319c. Has been placed. The auxiliary capacitance lower electrode 341 is formed in parallel with the slit 322 in the vicinity thereof, and is connected to the auxiliary capacitance lower electrodes 313a and 313c. The control electrode 345 is formed at a position facing the storage capacitor lower electrode 341 with the first insulating film interposed therebetween, and is connected to the control electrodes 319a and 319c.

  As described above, in the liquid crystal display device of this embodiment, the control electrode 345 having the same potential as the drain electrode 318a of the TFT 318 is formed below the region between the subpixel electrode 321b and the subpixel electrodes 321a and 321c. ing. Accordingly, a horizontal electric field is generated between the sub-pixel electrode 321b and the sub-pixel electrodes 321a and 321c, and an oblique electric field is generated between the sub-pixel electrodes 321a and 321c and the control electrode 345.

  Since the electric field strength (electric field density) is proportional to the potential difference and the distance between the electrodes, the distance between the subpixel electrode 321b and the subpixel electrodes 321a and 321c is set to 3.5 μm (same as the width of the slit 322). When the thickness of the insulating film between the control electrode 345 and the sub-pixel electrodes 321a and 321c is 0.33 μm, the influence of the oblique electric field on the liquid crystal molecules is larger than the influence of the horizontal electric field on the liquid crystal molecules. Will be bigger. For this reason, a dark line is generated only in the sub-pixel electrode 321b of the fine electrode portion at the end of the sub-pixel electrodes 321a and 321c, and the substantial aperture ratio is improved.

  FIG. 19 is a diagram showing transmittance characteristics and orientation characteristics in the liquid crystal display device of the present embodiment. In FIG. 19, the same components as those in FIG. As shown in FIG. 19, in the liquid crystal display device of this embodiment, dark lines are generated only on one side of the fine electrode portion (the portion surrounded by a broken line in FIG. 19) at the edge of the subpixel electrode 3. do not do. From comparison between FIG. 19 and FIG. 17, it can be seen that the liquid crystal display device of this embodiment has a substantially improved aperture ratio compared to the liquid crystal display device shown in FIG.

  In this embodiment, since the auxiliary capacitance lower electrode 341 is formed below the control electrode 345, the auxiliary capacitance is further increased as compared with the liquid crystal display device of the seventh embodiment. This has the advantage that the response time of the liquid crystal panel is further shortened.

  As shown in FIG. 20, the width of the auxiliary capacitance bus line 313 and the auxiliary capacitance electrode 319b may be reduced by the amount of the capacitance formed by the control electrode 345 and the auxiliary capacitance lower electrode 341. Thereby, there exists an advantage that a substantial aperture ratio improves further.

  When the difference in pixel capacitance ratio is converted into a voltage ratio applied to the liquid crystal, the voltage ratio is 0.96 in the liquid crystal display device shown in FIG. 18, and the voltage ratio is 0.94 in the liquid crystal display device shown in FIG. Also, the liquid crystal display devices shown in FIGS. 18 and 20 were actually manufactured, and their response speeds were measured. As a result, the response speed of the liquid crystal display device shown in FIG. 18 was 10 ms, and the response speed of the liquid crystal display device shown in FIG. 20 was 12 ms.

(Ninth embodiment)
FIG. 21 is a plan view showing one pixel of the liquid crystal display device according to the ninth embodiment of the present invention. In FIG. 21, the same components as those in FIG. 18 are denoted by the same reference numerals, and detailed description thereof is omitted.

  In the present embodiment, subpixel electrodes 351a and 351b are formed between the subpixel electrode 321b (directly connected pixel electrode) and the subpixel electrodes 321a and 321c (capacitive coupling pixel electrodes). These sub-pixel electrodes 351a and 351b are also formed of ITO in the same manner as the sub-pixel electrodes 321a to 321c. The subpixel electrodes 351a and 351b extend in the same direction as the fine electrode portions of the subpixel electrodes 321a to 321c in the vicinity thereof.

  The auxiliary capacitance lower electrode 341 and the control electrode 345 are formed in a region between the subpixel electrodes 351a and 351b and the subpixel electrodes 321a and 321c. The sub-pixel electrodes 351a and 351b are capacitively coupled to the control electrodes (the control electrodes 319a and 345 or the control electrodes 319c and 345) through the second insulating film. In the present embodiment, since the capacitance between the subpixel electrode 351 and the control electrode is large, a voltage higher than that of the control electrodes 321a and 321c is applied to the subpixel electrodes 351a and 351b. That is, in the present embodiment, the applied voltage decreases in the order of the control electrode 321b, the control electrodes 351a and 351b, and the control electrodes 321a and 321c.

  As described above, in the present embodiment, the potential difference between adjacent subpixels is smaller than that in the case where the subpixel electrode 351 is not provided. Thereby, generation | occurrence | production of the dark line by an azimuth | direction blurring can be reduced further.

  FIG. 22 is a diagram showing transmittance characteristics in the liquid crystal display device of the present embodiment. 22, the same components as those in FIG. 19 are denoted by the same reference numerals. From comparison between FIG. 22 and FIG. 19, it can be seen that the substantial aperture ratio of the liquid crystal display device of this embodiment is further improved as compared with the liquid crystal display device shown in FIG.

  When the difference in pixel capacitance ratio is converted into a voltage ratio applied to the liquid crystal, the voltage ratio is 0.94 in the liquid crystal display device of this embodiment. Moreover, as a result of actually manufacturing the liquid crystal display device of the present embodiment and measuring the response speed, the response speed was 12 ms.

(Tenth embodiment)
The tenth embodiment of the present invention will be described below.

  As described above, in the liquid crystal display device shown in FIG. 1, disorder of the alignment of liquid crystal molecules occurs at the base end portion and the tip end portion of the slit when a voltage is applied, which causes a substantial decrease in the aperture ratio. The substantial aperture ratio can be improved by extending the fine electrode portion to the vicinity of the data bus line.

  FIGS. 23A, 23B, 24A, and 24B are diagrams showing light transmission states when a voltage is applied in a liquid crystal display device in which the distance between the fine electrode portion and the data bus line is 7 μm or 5 μm. It is. However, FIGS. 23A and 23B show the light transmission state when there is no black matrix (BM), and FIGS. 24A and 24B both show the black matrix (BM). The light transmission state at a certain time is shown. Further, the widths of the fine electrode portions are all 6 μm, and the slit widths are all 3.5 μm.

23 (a) and 23 (b), it can be seen that a dark portion is generated at the tip portion of the fine electrode portion due to the disturbance of the liquid crystal molecules. From comparison between FIG. 23A and FIG. 23B, it can be seen that when the distance between the fine electrode portion and the data bus line is reduced, the dark area is reduced. In an actual liquid crystal display device, as shown in FIGS. 24A and 24B, the space between the fine electrode portion and the data bus line is covered with a black matrix. When the luminance of the liquid crystal display device in FIGS. 24A and 24B was measured, the luminance of the liquid crystal display device in FIG. 24A was 170 cd / m ² , and the luminance of the liquid crystal display device in FIG. Was 181 cd / m ² .

  As described above, by extending the fine electrode portion to the vicinity of the data bus line and covering the space between the fine electrode portion and the data bus line with a black matrix, the substantial aperture ratio of the liquid crystal display device is increased, and the luminance is increased. Can be improved. However, if the distance between the fine electrode portion and the data bus line is further reduced, display quality is deteriorated due to crosstalk.

  FIGS. 25A and 25B are diagrams showing the results of examining the transient characteristics of the liquid crystal display device from when a voltage is applied to the liquid crystal until the alignment is stabilized using a high-speed camera. However, FIG. 25A shows the transient characteristics of the liquid crystal display device in which linear polarizing plates are arranged on both sides of the liquid crystal panel, and FIG. 25B shows circular polarizing plates (linear polarizing plates + 1 /) on both sides of the liquid crystal panel. The transient characteristic of the liquid crystal display device which has arrange | positioned 4 wavelength plate is shown. The distance between the fine electrode portion and the data bus line is 7 μm, the width of the fine electrode portion is 6 μm, and the slit width is 3.5 μm. In a normal liquid crystal display device, 16.7 ms is one frame.

  It can be seen from FIGS. 25A and 25B that the luminance and response speed can be improved by using a circularly polarizing plate. However, since the circularly polarizing plate is more expensive than the linearly polarizing plate, the circularly polarizing plate may not be used depending on the application of the liquid crystal display device. FIG. 25A shows that the liquid crystal molecules at the base end portion and the tip end portion of the slit take time until the alignment is stabilized.

  Therefore, in this embodiment, the luminance and response characteristics of the liquid crystal display device are improved by improving the alignment of the liquid crystal molecules on the base end side and the front end side of the slit of the pixel electrode. The liquid crystal display device of the present embodiment will be described more specifically by Examples 1 to 4 shown below.

  In the following embodiments, a film made of a dielectric may be formed in the same shape as the slit instead of the slit. The dielectric film can also control the alignment direction of the liquid crystal molecules in the same manner as the slit, so that the same effect can be obtained.

Example 1
FIG. 26 is a plan view showing one pixel of the liquid crystal display device according to Example 1 of the tenth embodiment.

  On the TFT substrate, a gate bus line 412 extending in the horizontal direction (X-axis direction) and a data bus line 417 extending in the vertical direction (Y-axis direction) are formed. A storage capacitor bus line 413 is formed in parallel with the gate bus line 412 at the center of the rectangular pixel area defined by the gate bus line 412 and the data bus line 417.

  In addition, a TFT 418, a control electrode 419a, an auxiliary capacitance electrode 419c, and a pixel electrode 421 are formed for each pixel region.

  The TFT 418 uses a part of the gate bus line 412 as a gate electrode, and a drain electrode 418a and a source electrode 418b are arranged to face each other with the gate bus line 412 interposed therebetween. The control electrode 419a is electrically connected to the drain electrode 418a of the TFT 418. The auxiliary capacitance electrode 419c is formed at a position facing the auxiliary capacitance bus line 413 across the first insulating film, and is electrically connected to the drain electrode 418a of the TFT 418 via the control electrode 419a. .

  The pixel electrode 421 is formed of a transparent conductor such as ITO, and has four regions (domain control regions) in which the alignment directions of liquid crystal molecules are different from each other with a center line parallel to the X axis and a center line parallel to the Y axis as boundaries. ). In the upper right first region, a slit 422a extending in the 45 ° direction with respect to the X axis, a slit 422b extending in the 65 ° direction, and a slit 422c formed by combining a slit extending in the 45 ° direction and a slit extending in the 65 ° direction. Is formed. The upper left second region is formed by combining a slit 422d extending in the 135 ° direction with respect to the X axis, a slit 422e extending in the 115 ° direction, and a slit extending in the 135 ° direction and a slit extending in the 115 ° direction. A slit 422f is formed. Further, in the lower left third region, a slit 422g extending in the 225 ° direction with respect to the X axis, a slit 422h extending in the 245 ° direction, and a slit extending in the 225 ° direction and a slit extending in the 245 ° direction are combined. A slit 422i is formed. Furthermore, in the lower right fourth region, a slit 422j extending in the 315 ° direction with respect to the X axis, a slit 422k extending in the 295 ° direction, and a slit extending in the 315 ° direction and a slit extending in the 295 ° direction are combined. A slit 422m is formed.

  The pixel electrode 421 is electrically connected to the auxiliary capacitance electrode 419c through a contact hole 420a formed in the second insulating film. The surface of the pixel electrode 421 is covered with a vertical alignment film made of polyimide or the like.

  26 indicates the position of the edge of the black matrix formed on the counter substrate. Also in the liquid crystal display device of Example 1, the structure of the counter substrate is basically the same as that of the first embodiment, and therefore, the description thereof is omitted here. Further, in the liquid crystal display device of Example 1, a liquid crystal layer made of a liquid crystal having a negative dielectric anisotropy is disposed between the TFT substrate and the counter substrate, and added to the liquid crystal in the liquid crystal layer. A polymer formed by polymerizing the polymerized component (monomer or oligomer) by irradiating with ultraviolet rays in a state where a voltage is applied to the liquid crystal is included. This polymer determines the alignment direction of liquid crystal molecules when a voltage is applied.

  In the liquid crystal display device as shown in FIG. 1, for example, liquid crystal molecules in the vicinity of the connection electrode portion arranged along the center line of the pixel electrode parallel to the Y axis in the first region are electrically generated from the connection electrode portion. A force that tends to fall in a direction perpendicular to the connection electrode portion (a direction of 0 °) is generated by the force line. In addition, a force is applied to the liquid crystal molecules in the vicinity of the connection electrode portion by the slit so as to tilt in the 45 ° direction with respect to the X axis. As a result, the liquid crystal molecules in the vicinity of the connection electrode portion fall in a direction in which these two forces are balanced. That is, the direction in which the liquid crystal molecules in the vicinity of the connection electrode part tilt is smaller than 45 ° with respect to the X axis.

  On the other hand, in the liquid crystal display device of Example 1 shown in FIG. 26, for example, in the first region, the direction of the slit in the vicinity of the connection electrode portion is larger than 45 °. Can be tilted in the 45 ° direction. Thereby, generation | occurrence | production of the dark part in the connection electrode part vicinity is suppressed, and the transmittance | permeability improves. Moreover, since the alignment stability of the liquid crystal molecules in the vicinity of the connection electrode portion is improved, the response characteristics are improved.

(Example 2)
FIG. 27 is a plan view showing one pixel of a liquid crystal display device according to Example 2 of the tenth embodiment. The liquid crystal display device according to the second embodiment is different from the liquid crystal display device according to the first embodiment shown in FIG. 26 in that the shape of the slit provided in the pixel electrode is different. 27, the same components as those in FIG. 26 are denoted by the same reference numerals, and detailed description thereof is omitted.

  In the liquid crystal display device of Example 2, as shown in FIG. 27, the pixel electrode 441 is divided into four regions (domain control regions) with a center line parallel to the X axis and a center line parallel to the Y axis as boundaries. Each region is provided with a slit 442 extending in a direction parallel to the X axis. When a voltage is applied, all the liquid crystal molecules in each region are aligned along the slit 442 in the direction toward the center. That is, when a voltage is applied, the liquid crystal molecules in the upper right and lower right regions are tilted in the 180 ° direction with respect to the X axis, and the liquid crystal molecules in the upper left and lower left regions are tilted in the 0 ° direction with respect to the X axis.

  In the liquid crystal display device of the second embodiment, since the number of alignment divisions is 2, the viewing angle characteristics are worse than that of the liquid crystal display device of the first embodiment in which the alignment division number is 4. However, since the direction in which the liquid crystal molecules are tilted on the front end side (data bus line side) of the slit 442 coincides with the direction of the slit, there is an advantage that alignment failure on the front end side of the slit 442 is avoided. In addition, the alignment stability of the liquid crystal molecules on the tip side of the slit 442 is improved.

(Example 3)
FIG. 28 is a plan view showing one pixel of a liquid crystal display device according to Example 3 of the tenth embodiment. The liquid crystal display device of the third embodiment is different from the liquid crystal display device of the first embodiment shown in FIG. 26 in that the shape of the slit provided in the pixel electrode is different. 28, the same components as those in FIG. 26 are denoted by the same reference numerals, and detailed description thereof is omitted.

  Also in the liquid crystal display device of Example 3, as shown in FIG. 28, the pixel electrode 451 is divided into four regions (domain control regions) with a center line parallel to the X axis and a center line parallel to the Y axis as boundaries. Yes. In the upper right first region, a slit 452a extending in the 45 ° direction with respect to the X axis and a slit 452b extending in the 25 ° direction are provided. In the upper left second region, a slit 452c extending in the 135 ° direction with respect to the X axis and a slit 452d extending in the 155 ° direction are provided. Further, a slit 452e extending in the 225 ° direction with respect to the X axis and a slit 452f extending in the 205 ° direction are provided in the lower left third region. Furthermore, a slit 452g extending in the 315 ° direction with respect to the X axis and a slit 452h extending in the 335 ° direction are provided in the lower right fourth region.

  Also in the third embodiment, one pixel region is divided into four regions (domain control regions) in which the alignment directions of the liquid crystal molecules are different from each other by the slit provided in the pixel electrode 451. Each region is provided with a slit extending in the direction of 45 °, 135 °, 225 ° or 315 ° with respect to the X axis, and a slit extending in the direction of 25 °, 155 °, 205 ° or 335 °. . Thereby, compared with the liquid crystal display device shown in FIG. 1, it is possible to suppress the occurrence of a dark portion on the leading end side (data bus line side) of the slit.

Example 4
FIG. 29 is a plan view showing one pixel of a liquid crystal display device according to Example 4 of the tenth embodiment. The liquid crystal display device according to the fourth embodiment is different from the liquid crystal display device according to the first embodiment shown in FIG. 26 in that the shape of the slit provided in the pixel electrode is different. 29, the same components as those in FIG. 26 are denoted by the same reference numerals, and detailed description thereof is omitted.

  Also in the liquid crystal display device according to the fourth embodiment, as shown in FIG. 29, the pixel electrode 461 is divided into four regions (domain control regions) with a center line parallel to the X axis and a center line parallel to the Y axis as boundaries. ing. In the first area on the upper right, a slit whose base end side (connection electrode portion side) extends in a direction of 45 ° with respect to the X axis and whose distal end side (data bus line side) extends in a direction of 25 ° with respect to the X axis. 462a is provided. The upper left second region is provided with a slit 462b whose proximal end extends in a direction of 135 ° with respect to the X axis and whose distal end extends in a direction of 155 ° with respect to the X axis. Furthermore, the lower left third region is provided with a slit 462c whose base end side extends in the direction of 225 ° with respect to the X axis and whose front end side extends in the direction of 205 ° with respect to the X axis. Furthermore, the lower right fourth region is provided with a slit 462d whose proximal end extends in a direction of 315 ° with respect to the X axis and whose distal end extends in a direction of 335 ° with respect to the X axis.

  Also in the fourth embodiment, one pixel region is divided into four regions having different alignment directions of liquid crystal molecules by slits provided in the pixel electrode 461. And since the front end side of each slit is provided at an angle close to a right angle with respect to the data bus line 417, the occurrence of a dark portion at the front end of the slit can be suppressed. In addition, the alignment stability of the liquid crystal molecules at the slit tip is improved. Furthermore, it has been confirmed that by increasing the width of the fine electrode portion on the data bus line side as in Example 4, the occurrence of display unevenness due to stepper exposure when patterning the ITO film is suppressed. .

(Eleventh embodiment)
As described above, by forming the subpixel electrode (directly connected pixel electrode) directly connected to the TFT and the subpixel electrode (capacitively coupled pixel electrode) connected to the TFT through capacitive coupling in one pixel, the diagonal direction is obtained. Deterioration of display quality when viewed can be suppressed.

  In FIG. 30, the white display voltage is taken on the horizontal axis, and the area ratio of the directly connected pixel electrode to the entire area of the pixel electrode (direct connected pixel electrode ratio) is taken on the vertical axis. It is a figure which shows the relationship. In FIG. 30, a directly connected pixel electrode ratio of 0% indicates that only a capacitively coupled pixel electrode is present, and a directly connected pixel electrode ratio of 100% indicates that only a directly connected pixel electrode is present. The gamma shift amount is the average of the difference between the gamma value when the liquid crystal panel is viewed from the front and the gamma value when viewed from the direction of a polar angle of 60 ° (in the direction of 60 ° with respect to the normal of the panel). This value indicates that the smaller the gamma shift amount, the better the display quality when viewed from an oblique direction.

  In the liquid crystal display device (conventional example) shown in FIG. 1, since the directly connected pixel electrode ratio is 100%, the gamma shift amount is 2 when the white display voltage is 6 V from FIG. In addition, it can be seen from FIG. 30 that when the directly connected pixel electrode ratio is 10 to 40% and the white display voltage is 4 V, the amount of gamma shift is 1 or less, and the display quality is good when viewed from an oblique direction. However, in this case, since the white display voltage is low, the screen becomes dark. When the white display voltage is 6 V, if the area ratio of the directly connected pixel electrode is 10 to 70%, bright display is possible and the gamma shift amount is 1.4 or less, which is relatively high when viewed from an oblique direction. Good display quality can be maintained. Therefore, the area ratio of the directly connected pixel electrode is preferably 10 to 70%.

  FIG. 31 is a plan view showing a liquid crystal display device (part 1) according to an eleventh embodiment of the present invention. In this liquid crystal display device, the width L1 of the fine electrode portion of the directly connected pixel electrode 511b is 5 μm, the slit width S1 is 3.5 μm, the width L2 of the fine electrode portion of the capacitively coupled pixel electrodes 511a and 511c is 4 μm, and the slit width S2 is The ratio of the area M of the directly connected pixel electrode 511b and the area S of the capacitively coupled pixel electrodes 511a and 511c is set to M: S = 5: 5.

  FIG. 32 is a plan view showing a liquid crystal display device (part 2) according to the eleventh embodiment of the present invention. In this liquid crystal display device, the width L1 of the fine electrode portion of the directly connected pixel electrode 511b is 6 μm, the slit width S1 is 3.5 μm, the width L2 of the fine electrode portion of the capacitively coupled pixel electrodes 511a and 511c is 4 μm, and the slit width S2 is The ratio between the area M of the directly connected pixel electrode 511b and the area S of the capacitively coupled pixel electrodes 511a and 511c is set to M: S = 5: 5.

  FIG. 33 is a plan view showing a liquid crystal display device (part 3) according to the eleventh embodiment of the present invention. In this liquid crystal display device, the width L1 of the fine electrode portion of the directly connected pixel electrode 511b is 6 μm, the slit width S1 is 3.5 μm, the width L2 of the fine electrode portion of the capacitively coupled pixel electrodes 511a and 511c is 4 μm, and the slit width S2 is The ratio between the area M of the directly connected pixel electrode 511b and the area S of the capacitively coupled pixel electrodes 511a and 511c is set to M: S = 4: 6.

  FIG. 34 is a plan view showing a liquid crystal display device (part 4) according to the eleventh embodiment of the present invention. In this liquid crystal display device, the width L1 of the fine electrode portion of the directly connected pixel electrode 511b is 6 μm, the slit width S1 is 3.5 μm, the width L2 of the fine electrode portion of the capacitively coupled pixel electrodes 511a and 511c is 4 μm, and the slit width S2 is The ratio of the area M of the directly connected pixel electrode 511b to the area S of the capacitively coupled pixel electrodes 511a and 511c is set to M: S = 3: 7.

  Increasing the width of the fine electrode portion can suppress the occurrence of display unevenness due to stepper exposure when patterning the ITO film, but weakens the alignment regulating force on the liquid crystal molecules. As shown in FIGS. 31 to 34, the width of the fine electrode portion of the direct connection pixel electrode 511b is increased, and the width of the fine electrode portion of the capacitively coupled pixel electrodes 511a and 511c is reduced, thereby restricting alignment with respect to liquid crystal molecules. It is possible to prevent display unevenness due to stepper exposure while maintaining the force. Further, by setting the directly connected pixel electrode ratio within the range of 10 to 70%, the amount of gamma shift is reduced, and the display quality when viewed from an oblique direction is improved.

  In the first embodiment described above (see FIG. 3), a plurality of regions in which transmittance-applied voltage (TV characteristics) are different from each other by providing a directly connected pixel electrode and a capacitively coupled pixel electrode in one pixel. However, the transmittance-applied voltage characteristics in one pixel can also be changed within one pixel by changing the conditions (such as the ultraviolet intensity and the wavelength of the ultraviolet rays) when polymerizing the polymerization component added to the liquid crystal. A plurality of different regions can be formed.

  In addition, when the polymerization component added to the liquid crystal is polymerized, ultraviolet light may be irradiated by changing the voltage application condition in the red (R) pixel, the green (G) pixel, and the blue (B) pixel. As a result, the gamma characteristics of the red (R) pixel, the green (G) pixel, and the blue (B) pixel can be made uniform, and a liquid crystal display device with extremely little color shift can be realized.

  Furthermore, a region where monomer polymerization conditions are different from each other within one pixel, or a plurality of regions where the surface energy of the substrate surface is different from each other may be provided, and then the polymerization component added to the liquid crystal may be polymerized. A plurality of regions having different transmittance-applied voltage characteristics can be formed in one pixel. For example, by partially forming a resin film on the substrate, the conditions when the monomer added to the liquid crystal is polymerized and the surface energy of the substrate surface can be changed.

  In addition, a plurality of regions having different transmittance-applied voltage characteristics in one pixel can be obtained by providing a plurality of regions having different widths and slit widths (line and space) of the fine electrode portion in one pixel. Can be formed.

  Furthermore, in all of the above-described embodiments, the polymerization component added to the liquid crystal is polymerized by ultraviolet irradiation. However, the polymerization component may be polymerized by heat treatment, and polymerization is performed by using both ultraviolet irradiation treatment and heat treatment. The components may be polymerized.

  In each of the embodiments described above, an optical retardation film having a slow axis in a direction parallel to the substrate surface (liquid crystal panel surface) may be disposed in order to compensate for the optical anisotropy of the liquid crystal layer. .

  Hereinafter, various aspects of the present invention will be collectively described as supplementary notes.

(Supplementary Note 1) First and second substrates disposed to face each other;
A liquid crystal having negative dielectric anisotropy sealed between the first and second substrates;
Formed by polymerizing polymerization components added to the liquid crystal, and having a polymer that determines the direction in which liquid crystal molecules fall when a voltage is applied,
The first substrate includes, for each pixel, a switching element, a first sub-pixel electrode configured by a plurality of strip-shaped fine electrode portions and connection electrode portions that electrically connect them to each other, and a plurality of A second sub-pixel electrode configured by a band-shaped fine electrode portion and a connection electrode portion that electrically connects them to each other;
A common electrode facing the first and second subpixel electrodes is formed on the second substrate,
A first voltage is applied to the first subpixel electrode via the switching element, and a second voltage lower than the first voltage is applied to the second subpixel electrode. A characteristic liquid crystal display device.

  (Supplementary note 2) The liquid crystal display device according to supplementary note 1, wherein the first sub-pixel electrode is directly connected to the switching element.

  (Supplementary note 3) The liquid crystal display device according to supplementary note 1, wherein the second subpixel electrode is connected to the switching element through capacitive coupling.

  (Supplementary note 4) The liquid crystal display device according to supplementary note 3, wherein each of the first and second subpixel electrodes is divided into a plurality of regions in which the extending directions of the fine electrode portions are different from each other. .

  (Supplementary note 5) The supplementary note 4 is characterized in that the electrodes constituting the capacitive coupling are disposed below the first and second subpixel electrodes and along boundaries of the plurality of regions. The liquid crystal display device described.

  (Additional remark 6) Furthermore, it has the auxiliary capacity electrode which is electrically connected to the said 1st subpixel electrode, and comprises an auxiliary capacity, and the said auxiliary capacity electrode is arrange | positioned along the boundary of the said several area | region. Item 5. The liquid crystal display device according to appendix 4, wherein

  (Appendix 7) Further, a gate bus line to which a signal for turning on and off the switching element is supplied, a data bus line to be connected to the switching element and to which a display signal is supplied, and a first and a second encapsulating the liquid crystal The liquid crystal display device according to appendix 1, further comprising: a first polarizing plate and a second polarizing plate arranged with a second substrate interposed therebetween.

  (Supplementary Note 8) The direction in which the fine electrode portions of the first and second subpixel electrodes extend is a direction intersecting both the gate bus line and the data bus line, and the first and second polarizing plates. The liquid crystal display according to appendix 7, wherein an absorption axis of one of the polarizing plates is parallel to the gate bus line and an absorption axis of the other polarizing plate is a direction perpendicular to the gate bus line. apparatus.

  (Supplementary note 9) The liquid crystal display device according to supplementary note 7, wherein the data bus line has a bent shape.

  (Supplementary note 10) The liquid crystal display device according to supplementary note 9, wherein at least a part of the data bus line extends in a direction orthogonal to a direction in which the fine electrode portion extends.

  (Supplementary note 11) The liquid crystal display device according to supplementary note 10, wherein slits are provided only in end portions and bent portions of the first and second subpixel electrodes.

(Additional remark 12) The 1st and 2nd board | substrate arrange | positioned facing each other,
A liquid crystal having negative dielectric anisotropy sealed between the first and second substrates;
Formed by polymerizing polymerization components added to the liquid crystal, and having a polymer that determines the direction in which liquid crystal molecules fall when a voltage is applied,
The first substrate is formed with a pixel electrode composed of a switching element, a plurality of strip-shaped fine electrode portions, and a connection electrode portion that electrically connects them to each other for each pixel,
A liquid crystal display device having a notch in a portion of the tip portion of the fine electrode portion that does not face an adjacent fine electrode portion.

  (Supplementary note 13) The supplementary note 12, wherein L + d−S ≧ 4 μm is satisfied, where L is a width of the fine electrode portion, S is a distance between the fine electrodes, and d is a thickness of the liquid crystal layer. Liquid crystal display device.

  (Supplementary Note 14) Further, a gate bus line to which a signal for turning on and off the switching element is supplied, a data bus line to which a display signal is supplied connected to the switching element, and a first and a second encapsulating the liquid crystal Item 13. The liquid crystal display device according to appendix 12, wherein the liquid crystal display device includes first and second polarizing plates arranged with a second substrate interposed therebetween.

(Additional remark 15) The 1st and 2nd board | substrate arrange | positioned facing each other,
A liquid crystal having negative dielectric anisotropy sealed between the first and second substrates;
Formed by polymerizing polymerization components added to the liquid crystal, and having a polymer that determines the direction in which liquid crystal molecules fall when a voltage is applied,
The first substrate is formed with a pixel electrode composed of a switching element, a plurality of strip-shaped fine electrode portions, and a connection electrode portion that electrically connects them to each other for each pixel,
The liquid crystal display device according to claim 1, wherein the shape of the region between the fine electrode portions on the base end side of the fine electrode portion is a shape that is line-symmetric with respect to the center line of the region between the fine electrode portions.

  (Supplementary note 16) The liquid crystal display device according to supplementary note 15, wherein a shape of a region between the fine electrode portions on the base end side of the fine electrode portion is a rectangular shape.

  (Supplementary note 17) The liquid crystal display device according to supplementary note 15, wherein the shape of the region between the fine electrode portions on the base end side of the fine electrode portion is an isosceles triangle.

  (Supplementary note 18) Furthermore, a gate bus line to which a signal for turning on and off the switching element is supplied, a data bus line to which a display signal is supplied connected to the switching element, and a first and Item 16. The liquid crystal display device according to appendix 15, wherein the liquid crystal display device includes first and second polarizing plates arranged with a second substrate interposed therebetween.

(Supplementary note 19) first and second substrates disposed opposite to each other;
A liquid crystal having negative dielectric anisotropy sealed between the first and second substrates;
Formed by polymerizing polymerization components added to the liquid crystal, and having a polymer that determines the direction in which liquid crystal molecules fall when a voltage is applied,
The first substrate is formed with a pixel electrode composed of a switching element, a plurality of strip-shaped fine electrode portions, and a connection electrode portion that electrically connects them to each other for each pixel,
A portion of the distal end portion of the fine electrode portion that is not opposed to the adjacent fine electrode portion has a notch, and the shape of the region between the fine electrode portions on the proximal end side of the fine electrode portion is between the fine electrode portions. A liquid crystal display device having a shape which is line-symmetric with respect to the center line of the region.

(Supplementary note 20) first and second substrates disposed to face each other;
Liquid crystal sealed between the first and second substrates;
Formed by polymerizing polymerization components added to the liquid crystal, and having a polymer that determines the direction in which liquid crystal molecules fall when a voltage is applied,
On the first substrate,
A gate bus line extending in one direction,
A data bus line extending in a direction crossing the gate bus line;
An auxiliary capacity bus line parallel to the gate bus line;
Switching elements formed for each pixel region partitioned by the gate bus line and the data bus line;
The first switching element includes a plurality of band-shaped fine electrode portions and connection electrode portions that electrically connect them to each other, and has a plurality of domain control regions in which alignment directions of liquid crystal molecules are different from each other. A directly connected first subpixel electrode;
The liquid crystal molecules are arranged in the same pixel region as the first sub-pixel electrode, and are composed of a plurality of strip-shaped fine electrode portions and connection electrode portions that electrically connect them to each other, and the alignment directions of the liquid crystal molecules are mutually A second subpixel electrode having a plurality of different domain control regions;
An auxiliary capacitance electrode disposed at a position facing the auxiliary capacitance bus line across the first insulating film;
A capacitor is connected to the second subpixel electrode via a second insulating film, connected to the switching element, disposed at a position facing a boundary portion of the domain control region of the first and second subpixel electrodes. A control electrode to be coupled;
A storage capacitor lower electrode connected to the storage capacitor bus line and disposed at a position facing the control electrode across the first insulating film;
A liquid crystal display device, wherein a common electrode facing the first and second subpixel electrodes is formed on the second substrate.

  (Supplementary note 21) The supplementary note 20, wherein the first subpixel electrode is electrically connected to the auxiliary capacitance electrode through a contact hole formed in the second insulating film. Liquid crystal display device.

  (Supplementary note 22) The liquid crystal display device according to supplementary note 20, wherein the auxiliary capacitance electrode is disposed at a position facing a boundary of a domain control region of the first subpixel electrode.

  (Supplementary Note 23) In a region between the first and second subpixel electrodes, a second auxiliary capacitor lower electrode connected to the auxiliary capacitor lower electrode, and the first insulating film connected to the control electrode are provided. 21. The liquid crystal display device according to appendix 20, further comprising a second control electrode sandwiched and opposed to the second auxiliary capacitor lower electrode.

  (Supplementary Note 24) A third subpixel electrode capacitively coupled to the control electrode is formed between the first and second subpixel electrodes, and the second auxiliary capacitance lower electrode and the second control electrode are 24. The liquid crystal display device according to appendix 23, wherein the liquid crystal display device is disposed between the third subpixel electrode and the first subpixel electrode.

  (Supplementary Note 25) A voltage lower than a voltage applied to the first subpixel electrode and higher than a voltage applied to the second subpixel electrode is applied to the third subpixel electrode. 25. A liquid crystal display device according to appendix 24.

  (Supplementary note 26) The liquid crystal display device according to supplementary note 20, wherein the storage capacitor bus line and the control electrode are orthogonal to each other at the center of the pixel region.

  (Supplementary note 27) The liquid crystal display device according to supplementary note 20, wherein the liquid crystal is aligned perpendicular to the substrate surface when no voltage is applied.

(Supplementary note 28) first and second substrates disposed to face each other;
A liquid crystal having negative dielectric anisotropy sealed between the first and second substrates;
Formed by polymerizing polymerization components added to the liquid crystal, and having a polymer that determines the direction in which liquid crystal molecules fall when a voltage is applied,
On the first substrate, for each pixel, a switching element and a pixel electrode divided into a plurality of regions in which alignment directions of liquid crystal molecules are different from each other are formed,
The pixel electrode is composed of a plurality of band-shaped fine electrode portions formed for each region and a connection electrode portion for electrically connecting them, and the width of the pixel edge of the fine electrode portion is the center of the pixel. A liquid crystal display device characterized by being wider than the side width.

  (Supplementary note 29) The liquid crystal display device according to supplementary note 28, wherein the fine electrode portions of the pixel electrode are arranged substantially line-symmetrically or point-symmetrically.

  (Supplementary note 30) The liquid crystal display device according to supplementary note 28, wherein the polymerization of the polymerization component is performed by ultraviolet irradiation treatment, heat treatment, or a composite treatment thereof.

  (Supplementary note 31) The liquid crystal display device according to supplementary note 28, further comprising an optical retardation film having a slow axis in a direction parallel to the substrate surfaces of the first and second substrates enclosing the liquid crystal.

(Supplementary Note 32) First and second substrates disposed opposite to each other;
A liquid crystal having negative dielectric anisotropy sealed between the first and second substrates;
Formed by polymerizing polymerization components added to the liquid crystal, and having a polymer that determines the direction in which liquid crystal molecules fall when a voltage is applied,
On the first substrate, for each pixel, a switching element and a pixel electrode divided into a plurality of regions in which alignment directions of liquid crystal molecules are different from each other are formed,
2. The liquid crystal display device according to claim 1, wherein the pixel electrode is provided with two or more fine electrode portions having different extending directions in each region.

(Supplementary note 33) first and second substrates disposed to face each other;
A liquid crystal having negative dielectric anisotropy sealed between the first and second substrates;
Formed by polymerizing polymerization components added to the liquid crystal, and having a polymer that determines the direction in which liquid crystal molecules fall when a voltage is applied,
On the first substrate, for each pixel, a switching element and a pixel electrode divided into a plurality of regions in which alignment directions of liquid crystal molecules are different from each other are formed,
The liquid crystal display device, wherein the pixel electrode includes a plurality of fine electrode portions extending in a direction orthogonal to the data bus line.

(Supplementary Note 34) First and second substrates disposed opposite to each other;
A liquid crystal having negative dielectric anisotropy sealed between the first and second substrates;
Formed by polymerizing polymerization components added to the liquid crystal, and having a polymer that determines the direction in which liquid crystal molecules fall when a voltage is applied,
For each pixel, the first substrate is formed with a switching element and first and second subpixel electrodes divided into a plurality of regions in which alignment directions of liquid crystal molecules are different from each other.
The first subpixel electrode is composed of a plurality of band-shaped fine electrode portions extending in a predetermined direction for each region and a connection electrode portion electrically connecting them, and is directly connected to the switching element. And
The second subpixel electrode includes a plurality of band-shaped fine electrode portions extending in a predetermined direction for each region and a connection electrode portion that electrically connects them to each other, and performs the switching via capacitive coupling. Connected to the element,
The liquid crystal display device, wherein the width of the fine electrode portion of the first subpixel electrode is wider than the width of the fine electrode portion of the second subpixel electrode.

  (Supplementary note 35) The liquid crystal display device according to supplementary note 34, wherein in each of the first and second subpixel electrodes, the fine electrode portions are arranged substantially line-symmetrically or point-symmetrically.

  (Supplementary note 36) The liquid crystal display device according to supplementary note 34, wherein the polymerization of the polymerization component is performed by ultraviolet irradiation treatment, heat treatment, or a composite treatment thereof.

  (Supplementary note 37) The liquid crystal display device according to supplementary note 34, further comprising an optical retardation film having a slow axis in a direction parallel to the substrate surfaces of the first and second substrates enclosing the liquid crystal.

(Supplementary Note 38) First and second substrates disposed to face each other;
A liquid crystal having negative dielectric anisotropy sealed between the first and second substrates;
Formed by polymerizing polymerization components added to the liquid crystal, and having a polymer that determines the direction in which liquid crystal molecules fall when a voltage is applied,
For each pixel, the first substrate is formed with a switching element and first and second subpixel electrodes divided into a plurality of regions in which alignment directions of liquid crystal molecules are different from each other.
The first subpixel electrode is composed of a plurality of band-shaped fine electrode portions extending in a predetermined direction for each region and a connection electrode portion for electrically connecting them, and is directly connected to the switching element. And
The second subpixel electrode includes a plurality of band-shaped fine electrode portions extending in a predetermined direction for each region and a connection electrode portion that electrically connects them to each other, and performs the switching via capacitive coupling. Connected to the element,
The liquid crystal display device, wherein an area ratio of the first subpixel electrode to a total area of the first subpixel electrode and the second subpixel electrode is 10 to 70%.

  (Supplementary note 39) The liquid crystal display device according to supplementary note 38, wherein the fine electrode portions of the pixel electrode are arranged substantially line-symmetrically or point-symmetrically.

  (Supplementary note 40) The liquid crystal display device according to supplementary note 38, wherein the polymerization of the polymerization component is performed by ultraviolet irradiation treatment, heat treatment, or a composite treatment thereof.

  (Supplementary note 41) The liquid crystal display device according to supplementary note 38, further comprising an optical retardation film having a slow axis in a direction parallel to the substrate surfaces of the first and second substrates enclosing the liquid crystal.

  (Supplementary note 42) The liquid crystal according to any one of supplementary notes 1, 12, 15, 19, 20, 28, 32, 33, 34, and 38, wherein a slit is provided between the fine electrode portions. Display device.

  (Supplementary note 43) Any one of Supplementary notes 1, 12, 15, 19, 20, 28, 32, 33, 34, and 38, wherein a band-shaped dielectric film is formed between the fine electrode portions. A liquid crystal display device according to 1.

1, 3, 121a to 121c, 152a, 152b, 162a, 162b, 172a to 172c, 182a to 182c, 321a to 321c, 351a, 351b ... sub-pixel electrodes,
2, 313a, 313c, 341 ... auxiliary capacitor lower electrode,
4, 119a, 119c, 151a, 151c, 161a, 161c, 171, 313a, 313c, 319a, 319c, 345, 419a ... control electrodes,
11, 112, 211, 312, 412 ... gate bus lines,
12, 117, 177, 202, 212, 317, 417 ... data bus line,
14, 118, 214, 318, 418 ... TFT,
15, 215, 421, 441, 451, 461 ... pixel electrodes,
110, 310 ... TFT substrate,
111, 131, 311, 331 ... glass substrate,
113, 313, 413 ... auxiliary capacity bus line,
114, 120, 314, 320 ... insulating film,
115, 315 ... semiconductor film,
116, 316 ... channel protective film,
119b, 151b, 161b, 313b, 319b, 419c ... auxiliary capacitance electrode,
122,153,163,173,183,204,215a, 322,422a-422k. 422m, 422, 452a to 452h, 462a to 462d ... slits,
130, 330 ... counter substrate,
132,332 ... black matrix,
133,333 ... color filter,
134, 334 ... Common electrode,
140, 340 ... liquid crystal layer,
141a, 141b ... polarizing plates,
201, 215b ... fine electrode part,
205 ... Connection electrode part,
511b ... Directly connected pixel electrode (subpixel electrode),
511a, 511c... Capacitive coupling pixel electrodes (subpixel electrodes).

Claims (3)

First and second substrates disposed opposite each other;
A liquid crystal having negative dielectric anisotropy sealed between the first and second substrates;
Formed by polymerizing polymerization components added to the liquid crystal, and having a polymer that determines the direction in which liquid crystal molecules fall when a voltage is applied,
The first substrate is
A gate bus line extending in a first direction;
A data bus line extending in a second direction different from the first direction;
A switching element formed for each pixel and electrically connected to the gate bus line and the data bus line;
A plurality of strip-shaped fine electrode portions that are formed for each pixel and extend obliquely with respect to the data bus line, and a pixel electrode that includes a connection electrode portion that electrically connects them to each other;
A liquid crystal display device having a notch in a portion of the tip portion of the fine electrode portion adjacent to the data bus line that does not face the adjacent fine electrode portion. 2. The liquid crystal display according to claim 1, wherein L + d−S ≧ 4 μm is satisfied, where L is a width of the fine electrode portion, S is a distance between the fine electrodes, and d is a thickness of the liquid crystal layer. apparatus. Furthermore, it has the 1st and 2nd polarizing plate arrange | positioned on both sides of the 1st and 2nd board | substrate which enclosed the said liquid crystal,
2. The liquid crystal display device according to claim 1, wherein a signal for turning on and off the switching element is supplied to the gate bus line, and a display signal is supplied to the data bus line.

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