JP2009128466A - Liquid crystal display device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a liquid crystal display device capable of improving transmittance of an electrode in which slits are formed. <P>SOLUTION: Each of a plurality of pixels 3 that forms a display unit 2 is constituted of: at least first and second substrates 12 and 29 that is arranged oppositely to each other with liquid crystal molecules M disposed therebetween; and a common electrode 22 and a pixel electrode 24 that are disposed on one substrate of the first and the second substrates 12 and 29 with an insulating film 23 disposed therebetween so as to drive the liquid crystal molecules. In the electrode of the common electrode 22 and the pixel electrode 24 that is disposed closer to the liquid crystal molecules, at least a pair of slit forming regions A1 and A2 having a plurality of slits S1 and S2 having a predetermined tilt angle with respect to a rubbing direction and parallel to each other are disposed so that the slits S1 and S2 are axially symmetric with respect to a line orthogonal to the longitudinal direction of the pixel 3 and outer edges 31 and 32 on the sides opposite to the other slit forming region of the slit forming regions A1 and A2 are formed in parallel to the slits S1 and S2 formed in the inner part thereof. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a liquid crystal display device, and more particularly to a liquid crystal display device capable of improving transmittance.

  As a liquid crystal display device capable of obtaining a high contrast and a wide viewing angle, a liquid crystal display device that controls the orientation of liquid crystal molecules using an electric field in a substantially horizontal direction with respect to two transparent substrates, that is, FFS (Fringe-Field Switching) ) Mode and IPS (In-Plain Switching) mode are known. In this liquid crystal display device, one transparent substrate is provided with both a pixel electrode to which a display signal is supplied and a common electrode to which a common potential is supplied.

  The case where the liquid crystal display device is in the FFS mode will be described. For example, a plurality of linear portions and slits are alternately arranged in parallel on the pixel electrode, and the pixel electrode and the common electrode face each other with an insulating film therebetween. Be placed. The liquid crystal molecules are initially aligned according to the rubbing direction of the alignment film. When a display signal is applied to the pixel electrode, the liquid crystal molecules correspond to an electric field extending from the linear portion of the pixel electrode to the common electrode extending below the slit, that is, an electric field substantially in the horizontal direction with respect to the transparent substrate. The orientation direction is controlled. Optical control is performed through the liquid crystal molecules, and white display or black display is performed.

By the way, as this main FFS mode liquid crystal display device, for example, the first and second transparent insulating substrates are arranged to face each other at a predetermined distance through a liquid crystal layer containing a plurality of liquid crystal molecules, and are arranged on the first transparent substrate. A plurality of gate pass lines and data pass lines are formed and arranged in a matrix form so as to limit unit pixels, thin film transistors are provided at intersections with these, and counter electrodes made of a transparent conductor are arranged in each unit pixel. A plurality of upper and lower slits that form a fringe field together with the counter electrode are insulated from the counter electrode and arranged in each unit pixel, and are arranged with a predetermined inclination that is symmetrical about the long side of the pixel. Further, a fringe field switching mode liquid crystal display device having a configuration including a pixel electrode made of a transparent conductor has been proposed (for example, References 1).
JP 2002-182230 A (first page, FIG. 3)

  However, in the conventional example described in Patent Document 1, a rectangular pixel electrode is disposed in a region surrounded by the gate pass line and the data pass line, and the pixel electrode has a short side parallel to the gate pass line. A plurality of slits that are inclined in parallel with each other and a case in which an upper slit and a lower slit having an inclination angle that is symmetrical at the center position in the longitudinal direction of the pixel electrode are formed. Although the transmittance can be improved, the pixel electrode is formed in a rectangular shape and a slit that is inclined with respect to the short side is formed on the pixel electrode. A right-angled triangular electrode portion remains between the slit and the outer peripheral edge, and there is an unsolved problem that the transmittance is reduced at this portion.

  Therefore, the present invention has been made paying attention to the above-mentioned unsolved problems of the conventional example, and an object thereof is to provide a liquid crystal display device capable of improving the transmittance of an electrode forming a slit.

  In order to achieve the above object, a liquid crystal display device according to a first embodiment includes at least a pair of substrates facing each other with a liquid crystal layer interposed between pixels forming a display portion and one substrate of the pair of substrates. A common electrode and a pixel electrode that drive the liquid crystal molecules of the liquid crystal layer that are provided and arranged with an insulating film interposed therebetween, and the electrode on the liquid crystal layer side of the common electrode and the pixel electrode has a rubbing direction At least a pair of slit forming regions having slits inclined at a predetermined angle with respect to the angle between the longitudinal direction of the pixel and the longitudinal direction of the slit, and the pair of slits. An outer peripheral edge of one of the formation regions opposite to the other slit formation region is formed substantially parallel to the longitudinal direction of the slit.

In the first embodiment, the electrode on the liquid crystal layer side of the common electrode and the pixel electrode has at least a pair of slit forming regions having slits inclined at a predetermined angle with respect to the rubbing direction and the longitudinal direction of the pixel The slits are arranged so that the angle formed with the longitudinal direction of the slits is a complementary angle, and the outer peripheral edge of one of the pair of slit forming regions opposite to the other slit forming region is the slit. Since the outer shape of the electrode can be formed in a trapezoidal shape with a multi-slit configuration, there is no extra electrode portion on the opposite outer peripheral edge parallel to the slit of the electrode on which the slit is formed. Therefore, the transmittance of the pixel can be improved.
Further, in the liquid crystal display device according to the second mode, in the first mode, in each of the pair of slit forming regions, a plurality of slits formed in the electrode on the liquid crystal layer side are formed in parallel to each other. It is characterized by.

In the second embodiment, since a plurality of slits formed in the electrode on the liquid crystal layer side are formed in parallel with each other in each slit forming region, the transmittance in each slit forming region can be improved.
Furthermore, the liquid crystal display device according to a third aspect is the liquid crystal display device according to the first aspect or the second aspect, wherein the slit extends to one of the opposing outer peripheral edges in the longitudinal direction of the slit of the electrode on the liquid crystal layer side. The electrode has a comb shape.

In this 3rd form, since the electrode is made into the comb-tooth shape, the transmittance | permeability can be improved more.
Furthermore, the liquid crystal display device according to the fourth aspect is the liquid crystal display device according to any one of the first aspect to the third aspect, wherein the pair of slit formation regions of one electrode is disposed in the pixel. It is characterized by being.

In the fourth embodiment, since the electrode corresponding to one pixel is composed of electrodes having a multi-slit structure in which a pair of slit forming regions are formed, the transmittance between the pair of slit forming regions is reduced by narrowing the interval therebetween. Can be improved.
Still further, the liquid crystal display device according to the fifth mode is applied to one of the common electrode and the pixel electrode in the outer peripheral edge portion of one slit formation region of the electrode in which the slit is formed in the fourth mode. An active control unit for controlling the voltage is formed.

In the fifth embodiment, since the active control unit is formed at the outer peripheral edge of one slit formation region of the multi-slit configuration electrode, the active control unit can arrange the active control unit at the corner of the pixel, The transmittance of the entire pixel can be improved.
A liquid crystal display device according to a sixth aspect is the liquid crystal display device according to any one of the first to third aspects, adjacent to the other pixel of one of the pixels adjacent to the slit arrangement direction. The slit forming region and the slit forming region adjacent to one pixel of the other pixel are arranged so that the slits are parallel to each other.

In the sixth embodiment, since the slits of the adjacent slit forming regions of the adjacent pixels are arranged in parallel, a parallel slit is formed across the adjacent pixels in the slit arrangement direction. It is possible to form continuous pixels in the slit arrangement direction.
Furthermore, the liquid crystal display device according to a seventh aspect supplies the gate signal to the gate of the active control unit that controls the voltage applied to the pixel electrode at the boundary position between the pair of slit formation regions in the sixth aspect. A gate line is provided.

In the seventh embodiment, since the active control unit is arranged between the pair of slit formation regions in the pixel, the active control unit can be arranged using the switching unit in the slit direction in which the transmittance decreases. A pixel region having a slit configuration can be designed to a minimum.
Furthermore, the liquid crystal display device according to the eighth mode is characterized in that, in the seventh mode, the active control section is bent and intersects the gate line twice.

  In the sixth embodiment, since the active control section bends and intersects the gate line twice, the area of the thin film transistor formation region can be reduced and the ratio of the displayable region, that is, the aperture ratio can be improved.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 is a plan view showing an embodiment in which the present invention is applied to a liquid crystal display device operating in a normally black FFS mode. In FIG. 1, reference numeral 1 denotes a liquid crystal display device including a display unit. 2 includes a plurality of pixels 3 arranged in a matrix. In FIG. 1, only some pixels 3 of the display unit 2 are shown.

  As shown in FIG. 1, the display unit 2 is formed in a rectangular shape in which the X direction is a horizontal direction and the Y direction is a vertical direction, and a plurality of gate lines to which pixel selection signals are supplied along the horizontal direction. 4 are arranged at a predetermined interval, and drain lines 5 to which display signals are supplied are arranged at a predetermined interval along the vertical direction. The horizontal direction of the display unit 2 is set to be parallel to the absorption axis of the polarized sunglasses when the display unit 1 is viewed through the polarized sunglasses.

A pixel 3 is arranged in a pixel region surrounded by the gate line 4 and the drain line 5. Each pixel 3 is provided with a thin film transistor TR having the gate line 4 as a gate electrode at the upper left corner of the pixel formation region.
As shown in the cross-sectional view of FIG. 2, the pixel 3 has a first transparent substrate 12 made of glass or the like having a multilayer structure and a first polarizing plate 11 formed on the lower surface facing the backlight 10. A buffer film 13 is formed on the upper surface of the first transparent substrate 12, and an active layer 14 made of U-shaped polysilicon as viewed in FIG. The gate insulating film 15 is disposed so as to cover the active layer 14.

  On the upper surface of the gate insulating film 15 facing the active layer 14, the gate line 4 is disposed so as to pass through the active layer 14 twice to form a double gate structure. The gate insulating film 15 and the gate line 4 are covered with an interlayer insulating film 16. On the interlayer insulating film 16, a drain line 5 connected to the drain 17 of the thin film transistor TR through the contact hole CH1 and a source electrode 19 connected to the source 18 through the contact hole CH2 are arranged.

The drain line 5 and the source electrode 19 are covered with a passivation film 20, and a planarizing film 21 is formed on the passivation film 20. The passivation film 20 is not always necessary and can be omitted.
On the planarizing film 21, a common electrode 22 having an opening 22 a is disposed at a position facing the source electrode 19. For example, the common electrode 22 is formed as a solid film in the display effective region where the pixels 3 are arranged, and a common potential is supplied to the common electrode 22 through a contact hole (not shown) in the region where the pixels 3 are not arranged. It is connected to an electrode wire (not shown). Further, it may be formed in a strip shape connected in parallel to the gate line or the drain line, or the common electrode line may be connected to each pixel.

A pixel electrode 24 is disposed on the common electrode 22 via an insulating film 23. The pixel electrode 24 is connected to the source electrode 19 through a contact hole CH 3 formed through the insulating film 23, the opening 22 a of the common electrode 22, the planarizing film 21, and the passivation film 20.
The pixel electrode 24 is covered with an alignment film 25, and the rubbing direction of the alignment film 25 is set to be parallel to the transmission axis of the first polarizing plate 11.

  A second transparent substrate 29 having a color filter 27 and an alignment film 28 on the lower surface is disposed on the alignment film 25 via a liquid crystal layer 26 having liquid crystal molecules M. Here, the rubbing direction of the alignment film 28 has the same rubbing direction as the alignment film 25 described above. The liquid crystal molecules M of the liquid crystal layer 26 are initially aligned according to the rubbing direction of the alignment films 25 and 28 and are homogeneously aligned.

Further, a second polarizing plate 30 having a transmission axis orthogonal to the first polarizing plate 11 is disposed on the upper surface of the second transparent substrate 29.
The rubbing direction of the alignment films 25 and 28 coincides with the horizontal direction (X direction) as shown in FIG. As shown in FIG. 3, the pixel electrode 24 has a double slit configuration having a pair of first slit formation region A1 and second slit formation region A2 having a vertically symmetrical slit shape at the center in the longitudinal direction of the pixel 3. ing.

In the first slit formation region A1, a plurality of slits S1 having a rectangular shape inclined by a predetermined angle + θs1 with respect to the rubbing direction of the alignment films 25 and 28 are formed in parallel with a predetermined interval L1 in the vertical direction.
In the second slit formation region A2, a plurality of slits S2 having a rectangular shape inclined by a predetermined angle −θs1 with respect to the rubbing direction of the alignment films 25 and 28 are formed in parallel in the vertical direction with a predetermined interval L1. ing.

Therefore, the first slit forming region A1 and the second slit forming region A2 are arranged such that the angle formed by the longitudinal direction of the pixel 3 and the longitudinal direction of the slits S1 and S2 is a complementary angle.
The pixel electrode 24 is formed such that the outer peripheral edge 31 on the first slit forming region A1 side is a short side parallel to the slit S1 at a position away from the outermost peripheral slit S1 by a predetermined distance L2. The outer peripheral edge 32 on the slit forming area A2 side is formed to be a short side parallel to the slit S2 at a position separated from the outermost slit S2 by L2.

The pixel electrode 24 is formed with opposed outer peripheral edges 33 and 34 having relatively long long sides extending along the drain line 5 in the vertical direction by individually connecting the left and right ends of the outer peripheral edges 31 and 32, respectively. The outer peripheral edges 31 to 34 are formed in a trapezoidal shape.
Here, each of the slits S1 and S2 of the first slit region A1 and the second slit region A2 is between the pixel electrode 24 that is the upper electrode and the common electrode 22 that is the lower electrode formed through the insulating film 23. It is an opening for driving the liquid crystal molecules M with an electric field generated by applying a voltage. By forming a plurality of slits S1 parallel to the vertical direction (Y direction) in each of the slit regions A1 and A2, the transmittance in each of the slit regions A1 and A2 can be improved.

Then, the slit S1 of the first slit formation region A1 has, for example, an inclination angle + θs1 with respect to the rubbing direction of the alignment films 25 and 28 in order to prevent the rotation direction of the liquid crystal molecules M of the liquid crystal layer 26 from being indefinite. It is set to a value about +5 degrees to +15 degrees, preferably about +5 degrees larger.
In addition, the slit S2 of the second slit formation region A2 also has an inclination angle −θs1 with respect to the rubbing direction of the alignment films 25 and 28 in order to prevent the rotation direction of the liquid crystal molecules M of the liquid crystal layer 26 from being indefinite. For example, it is set to a value that is about -5 degrees to -15 degrees, preferably about -5 degrees smaller.

  Further, the slits S1 and S2 are formed such that both end portions in the longitudinal direction are inside a predetermined distance L3 with respect to the opposing outer peripheral edges 33 and 34 of the pixel electrode 24 facing the both end portions. Eventually, the pixel electrode 24 has a trapezoidal shape with the outer electrode portions 35 and 36 forming the opposing outer peripheral edges 31 and 32 and the outer electrode portions 37 and 38 forming the opposing outer peripheral edges 33 and 34. And 38 are connected by a connecting electrode portion 39 forming slits S1 and S2.

Furthermore, the slits S1 and S2 at the boundary position between the first slit formation region A1 and the second slit formation region A2 are formed so that the connection electrode portions 39 overlap each other at the position of the outer electrode portion 37, and the outer electrode portion 38 side. In addition, a slit S3 having an end opened to the outer peripheral edge 34 is formed.
Depending on the resolution of the photolithography process, the slit S3 is opened on the outer peripheral edge 34 side when the inclination angles + θs1 and −θs1 with respect to the rubbing direction of the slits S1 and S2 are small and the slit width is small, as shown in FIG. In the case of the shape, when the inclination angles + θs1 and −θs1 are large and the slit width is large, the outer electrode portion 38 side end portion can be closed.

When the pixel electrode 24 is patterned, the corner may be slightly rounded by a photolithography process. In order to avoid this roundness as much as possible, if the pattern of the mask used for patterning is a pattern considering the optical proximity effect, the roundness can be suppressed to a level that can be ignored.
The thin film transistor TR described above is formed in the lower left corner of the second slit formation region A2 of the pixel electrode 24.

  Further, as shown in FIG. 1, at least the outer electrode portion 35 of the pixel electrode 24 and the drain line 5 are arranged so that they partially overlap each other when viewed from above, so that the end portion of the slit S1 is drained. It can be brought closer to the line 5 and the transmittance in the pixel 3 can be further improved. Further, by arranging the outer electrode portion 35 of the pixel electrode 24 and the gate line 4 so as not to overlap each other, the outer electrode portion 35 and the common electrode 22 that is a lower electrode formed larger than the pixel electrode 24 Thus, the liquid crystal molecules M between the outer electrode portion 35 and the gate line 4 can be controlled by the electrolysis, and the transmittance in the pixel 3 can be further improved.

  The operation of the liquid crystal display device 1 having the above configuration will be described with reference to FIG. 2. In an off state where no electric field is generated between the common electrode 22 and the pixel electrode 24, the liquid crystal molecules M of the liquid crystal layer 26 are homogeneously aligned. The long axis direction is, for example, parallel to the transmission axis of the first polarizing plate 11. At this time, the light of the backlight 10 linearly polarized by the first polarizing plate 11 passes through the liquid crystal layer 26 with the polarization axis as it is and enters the second polarizing plate 30. However, this light is absorbed by the second polarizing plate 30 because its polarization axis is perpendicular to the transmission axis of the second polarizing plate 30. That is, the display is black (normally black).

  On the other hand, in the ON state in which an electric field is generated between the common electrode 22 and the pixel electrode 24, the major axis of the liquid crystal molecules M of the liquid crystal layer 26 is substantially horizontal with respect to the first transparent substrate 12 according to the electric field. Rotate. At this time, the light of the backlight 10 linearly polarized by the first polarizing plate 11 becomes elliptically polarized light due to birefringence in the liquid crystal layer 26, and enters the second polarizing plate 30. Among the elliptically polarized light, a component that coincides with the transmission axis of the second polarizing plate 30 is emitted and white display is performed.

At this time, the outer peripheral edges 31 and 32 of the outer electrode portions 35 and 36 of the pixel electrode 24 are formed in parallel with the slits S1 and S2, respectively, so that the outer shape of the pixel electrode 24 is larger than that of a rectangular shape. There is no extra margin in the electrode portions 35 and 36, and the transmittance of each pixel 3 can be improved.
In addition, since the thin film transistor TR has a double gate structure in which the gate line 4 passes through the active layer 14 twice, the area of the thin film transistor formation region can be reduced and the ratio of the displayable region, that is, the aperture ratio can be improved.

  When each pixel 3 on which the pixel electrode 24 is arranged operates by so-called line inversion driving, display signals having different polarities are supplied to the pixel electrodes 24 of the pixels 3 adjacent in the vertical direction. Therefore, a desired display may not be obtained by processing between different display signals, and a display defect may occur in the vicinity of the boundary between the pixels 3. In order to avoid this problem, it is preferable to separate the pixel electrodes 24 of the pixels 3 adjacent in the vertical direction as much as possible. However, if the separation distance is too large, the transmittance is lowered.

  Therefore, the distance between the opposing outer peripheral edge 31 of one pixel electrode 24 and the opposing outer peripheral edge 32 of the other pixel electrode 24 is such that the liquid crystal molecules M outside the opposing outer peripheral edges 31 and 32 of the pixel electrode 24 are rotated by a desired electric field. It is preferable to make the range equal to or slightly larger than twice the range in which the value can be obtained. For example, among adjacent pixel electrodes 24, if the distance between the outer peripheral edge 31 of one pixel electrode 24 and the outer peripheral edge 32 of the other pixel electrode 24 is D1, 5 μm <D1 <15 μm, which is a preferable example Is 7 μm <D1 <10 μm.

  In the first embodiment, when the end shape of the slit S1 is rounded, there is a region where the rotation direction of the liquid crystal molecules M is reversed with respect to a desired direction. Disclination, which is a phenomenon in which the area to be displayed is black and the transmittance is reduced, occurs. In order to suppress the occurrence of this disclination, it is necessary to form the end shape of the slit S1 without rounding. As a mask used in the photolithography process for this purpose, as shown in FIG. In addition, the opening electrode formation mask 100 is used.

  In the opening electrode forming mask 100, a basic light-transmitting pattern portion 113 corresponding to the shape of the slit S1 is formed at a position facing the first slit forming region A1 of the pixel electrode 24 with respect to the non-light-transmitting pattern portion 112. A basic light-transmitting pattern portion 114 corresponding to the shape of the slit S2 is formed at a position facing the second slit formation region A2. Further, the correction light-transmitting pattern portions 115, 116, and 117, which suppress the occurrence of disclination by expanding the basic light-transmitting pattern portions 113 and 114 to the portions where the disclination occurs in the basic light-transmitting pattern portions 113 and 114, 118 is formed.

  Here, the part where the disclination occurs in the basic translucent pattern portion 113 is the slit S1 because the slit S1 of the first slit formation region A1 is inclined in the positive direction, that is, counterclockwise with respect to the rubbing direction. Is the corner of the second quadrant and the fourth quadrant where the X direction is the longitudinal direction of the slit and the Y direction is the width direction of the slit. Further, the disclination portion of the basic translucent pattern portion 114 has the XY coordinates because the slit S2 of the second slit forming area A2 is inclined in the negative direction, that is, in the clockwise direction with respect to the rubbing direction. In the system, it becomes the corner E of the first quadrant and the third quadrant.

  Since each of the correction translucent pattern portions 115 to 118 has the same shape, the correction translucent pattern 115 will be described as a representative. The correction translucent pattern 115 communicates with the basic translucent pattern portion 113 so that the basic translucent pattern portion 113 extends into the non-transparent pattern portion 112 as shown in an enlarged view in FIG. Is formed. The correction translucent pattern 115 communicates with the basic translucent pattern portion 113, and extends in a direction inclined by, for example, 45 degrees counterclockwise with respect to the longitudinal direction, that is, the X axis, for example, a strip-shaped pattern portion 119. And a triangular pattern portion 120 formed at an extended end of the band-shaped pattern portion 119, for example, a right-angled isosceles triangle.

Here, the width dimension B of the band-shaped pattern part 119 and the extension dimension C from the end of the basic light transmission pattern 113 to the tip of the triangular pattern part 120 are set smaller than the width dimension A of the basic light transmission pattern part 113. Yes.
As an example of the dimensions, when the slit width S of the pixel electrode 24 formed after etching is about 4.0 μm, the width dimension A of the basic translucent pattern portion 114 can be about 3.4 μm. In this case, the extension dimension C of the correction translucent pattern portion 116 can be about 1.75 μm, and the width dimension B can be about 1.4 μm.

  In a high-definition liquid crystal display device, the width dimension A of the basic light-transmitting pattern portion 114 is often set to the minimum dimension near the resolution limit of the exposure apparatus. Therefore, normally, even if the minimum dimension of the pattern of the opening electrode formation mask is smaller than the resolution of the exposure apparatus, it cannot be exposed to a desired dimension and shape. Here, by utilizing the optical proximity effect, it is possible to obtain a fine pattern having a resolution lower than that of the exposure apparatus. This is to correct the shape of the peripheral portion of the basic pattern portion by providing a pattern portion for correcting the shape and dimensions in consideration of light diffraction etc. in the peripheral portion of the basic pattern portion near the resolution limit of the exposure apparatus, This is based on the ability to form a pattern with an accuracy higher than the resolution of the exposure apparatus. In the example of FIG. 4, the exposure pattern has an arc shape at the end in the longitudinal direction due to the limit of the resolution of the exposure apparatus only with the basic light transmission pattern portion 113, but the correction light transmission pattern portion 115 is provided. Thus, the arc shape can be corrected to obtain an exposure pattern that is very close to a rectangle.

  Therefore, in order to use the optical proximity effect, the dimension of the correction translucent pattern portion 115 is set smaller than the minimum dimension of the basic translucent pattern portion 113. In the above example, if the resolution of the exposure apparatus is about 3 μm, the minimum dimension of the basic light-transmitting pattern portion 113 is set to about 3.4 μm, which is larger than the resolution of the exposure apparatus of about 3 μm. The minimum dimension can be set to 1.4 μm, which is smaller than the resolution of the exposure apparatus of 3 μm.

  In such an opening electrode forming mask 100, the minimum dimension of the basic translucent pattern portion 113 is set within the allowable range of the resolution of the exposure apparatus in accordance with a general exposure mask manufacturing method, and the longitudinal direction of the basic translucent pattern portion 113 is set. It is possible to use a light-transmitting pattern formed on the end so as to provide a correction light-transmitting pattern portion 115 having a small dimension exceeding the resolution of the exposure apparatus.

The correction translucent pattern portions 116 to 118 are also formed in the same shape that is symmetrical with the correction translucent pattern portion 115, although detailed illustration is omitted.
When exposure is performed using the opening electrode formation mask 100 having the above-described configuration, light passes through the basic light-transmitting pattern portions 113 and 114 and the correction light-transmitting pattern portions 115 to 118, and the photosensitive resist is exposed. . Since the characteristics of the photosensitive resist change when it is exposed, the exposed portion can be removed by using an appropriate developer, whereby the photosensitive resist becomes the basic light-transmitting pattern portions 113 and 114. An opening is formed in the photosensitive resist in the same shape. The pixel electrode 24 having the slits S1 and S2 having a shape corresponding to the opening of the photosensitive resist is obtained by etching the transparent conductive material film for the pixel electrode using the photosensitive resist having the opening formed in this manner. Is formed.

Next, a second embodiment of the present invention will be described with reference to FIGS.
In the second embodiment, a thin film transistor TR is formed at the boundary between the first slit forming part A1 and the second slit forming part A2.
That is, in the second embodiment, as shown in FIG. 6, the thin film transistor TR is formed at the boundary between the first slit forming region A1 and the second slit forming portion A2 of the pixel electrode 24 in the pixel 3, and the vertical direction In other words, the pixel 3 adjacent to the drain line 5 has the same configuration as that of the first embodiment except that the direction of the pixel electrode 24 is reversed left and right. Are denoted by the same reference numerals, and detailed description thereof will be omitted.

In the second embodiment, the absolute values of the inclination angles + θs1 and −θs1 of the slits S1 and S2 in the first slit formation region A1 and the second slit formation region A2 are set to be larger than those in the first embodiment described above. Has been.
In addition, slits S1 'and S2' at the boundary position between the first slit forming area A1 and the second slit forming area A2 are communicated with each other on the outer peripheral electrode portion 37 side as shown in an enlarged view in FIG. At the same time, the outer peripheral electrode portion 38 side is closed at a position away from the outer peripheral electrode portion 37 by a distance L5 larger than the distance L2, and the transistor counter electrode portion 40 is formed.

  Then, as shown in FIG. 7, a U-shaped active layer 14 as viewed in FIG. 6 is formed facing the lower side of the transistor counter electrode portion 40, and between the drain 17 and the source 18 of this active layer 14. A thin film transistor TR having a double gate structure is formed so that the gate line 4 passes twice. The source 18 of the thin film transistor TR is electrically connected to the transistor counter electrode portion 40 through the contact hole CH2, the source electrode 19, and the contact hole CH3.

  According to the second embodiment, the transistor counter electrode portion 40 facing the thin film transistor TR is formed at the boundary position between the first slit forming area A1 and the second slit forming area A2 in which the inclination directions of the slits S1 and S2 are different, As shown in FIG. 7, the transistor counter electrode portion 40 is connected to the source 18 of the thin film transistor TR, and the gate line 4 is disposed so as to cross the active layer 14 of the thin film transistor TR twice. As shown, the gate line 4 can be disposed so as to cross the central portion of one pixel 3 in the vertical direction, and the design for minimizing the pixel 3 can be performed.

In addition, as described above, the thin film transistor TR has a double gate structure, so that the configuration can be reduced in size, and the space between the first slit formation region A1 and the second slit formation region A2 can be narrowed. Can be minimized.
Further, since the adjacent pixel electrodes 24 are reversed left and right, the slits S1 or S2 are continuous in parallel between the adjacent pixels 3, and there is no break between the pixels 3, so that the adjacent pixels 3 The transmittance can be improved.

Next, a third embodiment of the present invention will be described with reference to FIGS.
In the third embodiment, the pixel electrode is formed in a comb shape.
That is, in the third embodiment, as shown in FIGS. 9 and 10, the outer electrode portion 38 on the right side of the pixel electrode 24 in the first embodiment described above is not formed, and the pixel electrode 24 is formed in a comb shape. Except for the above, the configuration is the same as that of FIG. 1 and FIG. 3 described above, and the same reference numerals are given to the corresponding parts to FIG. 1 and FIG.

According to the third embodiment, since the outer electrode portion 38 of the pixel electrode 24 in the first embodiment is not formed, and the pixel electrode 24 is a comb-like pixel electrode, the end of the slit S1 is not formed, The transmittance can be improved.
Also in the third embodiment, it is necessary to form the comb-like pixel electrode 24 without rounding the end shape in order to prevent disclination, and this is used in the photolithography process for this purpose. As the mask, an opening electrode formation mask 200 as shown in FIG. 11 is used.

  The opening electrode forming mask 200 has basic light-transmitting pattern portions 213 and 214 corresponding to the shapes of the slits S1 and S2 at positions facing the slits S1 and S2 of the pixel electrode 24 with respect to the non-light-transmitting pattern portion 212. Further, the non-transparent pattern portion 215 for correction that suppresses the occurrence of disclination by reducing the basic translucent pattern portions 213 and 214 to the portion where the disclination of the basic translucent pattern portions 213 and 214 occurs. 216 and basic translucent pattern portions 313 and 214 are formed to form correction translucent pattern portions 217 and 218 that suppress the occurrence of disclination.

  Here, the part where the disclination of the basic translucent pattern portion 213 occurs is inclined in the positive direction, that is, counterclockwise with respect to the rubbing direction like the slit S1, as in the first embodiment described above. When the center point of the slit S1 is the origin of the XY coordinates, the X direction is the longitudinal direction of the slit, and the Y direction is the width direction of the slit, the corners of the second quadrant and the fourth quadrant are obtained. . Further, when the disclination portion of the basic translucent pattern portion 214 is inclined in the negative or clockwise direction with respect to the rubbing direction like the slit S2, the first quadrant in the XY coordinate system is used. And the corner E of the third quadrant.

  As shown in the enlarged view of FIG. 12, the non-transparent pattern portion 215 for correction has a shape in which the non-transparent pattern portion 212 is expanded into the basic translucent pattern portion 213, in other words, the basic translucent pattern portion 213 is reduced. The non-transparent pattern portion 212 is connected to the non-transparent pattern portion 212, and is connected to the non-transparent pattern portion 212 so as to extend at an angle of 45 degrees counterclockwise with respect to the longitudinal direction, that is, the X axis. The band-shaped non-light-transmitting pattern portion 219 having a narrow width and the triangle non-light-transmitting pattern portion 220 formed at an extended end of the band-shaped non-light-transmitting pattern portion 219, for example, a right-angled isosceles triangle.

Here, the width dimension I of the band-shaped non-transparent pattern portion 219 and the extension dimension J from the end of the non-translucent pattern 212 to the tip of the triangular non-transparent pattern portion 220 are the width dimension H of the non-transparent pattern portion 212. Is set smaller than.
For example, when the width of the elongated electrode portion of the pixel electrode 24 formed after etching, that is, the width W of the line is about 3.0 μm, the width H of the non-light-transmitting pattern portion 212 is about 3. In this case, the extension dimension J of the non-transparent pattern portion for correction 216 can be about 1.5 μm, and the width dimension I can be about 1.4 μm.

  As described above with reference to FIGS. 4 and 5, by using the optical proximity effect, it is possible to obtain a fine pattern below the resolution of the exposure apparatus. In the example of FIG. With only the non-transparent pattern 212, the arc shape is corrected by providing a fine correction non-transparent pattern portion 215 in an arc shape at the end in the longitudinal direction due to the limit of the resolution of the exposure apparatus. Thus, the exposure pattern can be made substantially rectangular.

  Therefore, in order to use the optical proximity effect, the dimension of the correction non-light-transmitting pattern part 215 is set smaller than the minimum dimension of the basic light-transmitting pattern part 214 or the non-light-transmitting pattern 212. In the above example, assuming that the resolution of the exposure apparatus is about 3 μm, the minimum dimension of the basic translucent pattern portion 214 is set to about 3.6 μm, which is larger than the resolution of the exposure apparatus of about 3 μm, and the non-transparent pattern for correction The minimum dimension of the portion 216 can be about 1.4 μm, which is smaller than the resolution of the exposure apparatus of 3 μm.

  In such an opening electrode forming mask 200, the minimum dimension of the basic light-transmitting pattern portion 213 is set within the allowable range of the resolution of the exposure apparatus in accordance with a general exposure mask manufacturing method, and the longitudinal light-transmitting pattern portion 213 is arranged in the longitudinal direction. A light-transmitting pattern formed so that a correction light-transmitting pattern portion 215 having a small dimension exceeding the resolution of the exposure apparatus can be provided at the end.

Further, the correction translucent pattern portions 216 and 218 have the same configuration as the correction translucent pattern portion 117 of FIGS. 4 and 5 described above, and the correction translucent pattern 217 has a configuration of the correction translucent pattern. 215 and line symmetry.
In the third embodiment, the case where the pixel electrode 24 of the first embodiment described above is comb-shaped has been described. However, the present invention is not limited to this, and the pixel electrode of the second embodiment described above. May be comb-shaped.

  In the first to third embodiments, the pixel electrode 24 of the common electrode 22 and the pixel electrode 24 is disposed on the liquid crystal molecule M side, and the first slit formation region A1 and the first slit forming region A1 having the slits S1 and S2 are used. Although the case where the two-slit formation region A2 is formed has been described, the present invention is not limited to this, and when the common electrode 22 is disposed on the liquid crystal molecule M side, the common electrode 22 is used instead of the pixel electrode 24. The first slit forming area A1 and the second slit forming area S2 having the slits S1 and S2 may be formed.

  Furthermore, in the first to third embodiments, the active layer 14 of the thin film transistor TR is formed in a U shape, and the active layer 14 has a double gate structure so that the gate line 4 crosses twice. Although described above, the present invention is not limited to this, and as shown in FIG. 13, the active layer 14 is formed in a straight line, and the branching portion branches into the gate line 4 at the position of the active layer 14 accordingly. 300 may be formed so that the active layer 14 has a double gate structure in which the gate line 4 crosses twice.

  In the first to third embodiments, the case where the pixel 3 operates in the normally black FFS mode has been described. However, the present invention is not limited to this, and the normally white FFS mode is used. The present invention can also be applied to a liquid crystal display device that operates according to the above. In this case, the relationship between the transmission axes of the first polarizing plate 11 and the second polarizing plate 30 and the rubbing direction of the alignment films 25 and 28 may be changed corresponding to the normally white type.

1 is a plan view showing a liquid crystal display device according to a first embodiment of the present invention. It is sectional drawing on the AA of FIG. It is a top view which shows the pixel electrode of FIG. It is a top view which shows the mask for opening part application applied to 1st Embodiment. It is a figure which shows the detail of the correction | amendment translucent pattern part of FIG. It is a top view which shows the liquid crystal display device of the 2nd Embodiment of this invention. It is sectional drawing on the AA line of FIG. It is a top view which shows the pixel electrode of FIG. It is a top view which shows the liquid crystal display device of the 3rd Embodiment of this invention. FIG. 10 is a plan view showing the pixel electrode of FIG. 9. It is a top view which shows the mask for opening part application applied to 3rd Embodiment. It is a figure which shows the detail of the correction | amendment non-translucent pattern part of the mask for opening part formation. It is a top view which shows the other structure of a thin-film transistor.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Liquid crystal display device, 2 ... Display part, 3 ... Pixel, 4 ... Gate line, 5 ... Drain line, 10 ... Back light, 11 ... 1st polarizing plate, 12 ... 1st transparent substrate, 13 ... Buffer film , 14 ... Active layer, 15 ... Gate insulating film, 16 ... Interlayer insulating film, 17 ... Drain, 18 ... Source, 19 ... Source electrode, 20 ... Passivation film, 21 ... Planarization film, 22 ... Common electrode, 23 ... Insulation Film, 24 ... pixel electrode, 25 ... alignment film, 26 ... liquid crystal layer, 27 ... color filter, 28 ... alignment film, 29 ... second transparent substrate, 30 ... second polarizing plate, TR ... thin film transistor, A1 ... first 1 slit forming area, A2 ... second slit forming area, S1, S2 ... slit, 31, 32 ... opposing outer peripheral edge, 33, 34 ... opposing outer peripheral edge, 35 to 38 ... outer electrode part, 39 ... connecting electrode part, 40 ... transistor counter electrode, 1 DESCRIPTION OF SYMBOLS 0 ... Mask for opening part, 112 ... Non-light-transmitting pattern part, 113, 114 ... Basic light-transmitting pattern part, 115-118 ... Light-transmitting pattern part for correction, 200 ... Mask for opening part forming, 212 ... Non-light-transmitting Pattern part, 213, 214 ... Basic light transmission pattern part, 215, 217 ... Correction non-light transmission pattern part, 216, 218 ... Correction light transmission pattern part

Claims (8)

A pixel forming the display portion drives at least a pair of substrates opposed to each other with a liquid crystal layer interposed therebetween, and liquid crystal molecules of the liquid crystal layer provided on one of the pair of substrates with an insulating film interposed therebetween. A common electrode and a pixel electrode,
Of the common electrode and the pixel electrode, the electrode on the liquid crystal layer side includes at least a pair of slit forming regions having slits inclined at a predetermined angle with respect to the rubbing direction, and the longitudinal direction of the pixel and the longitudinal direction of the slit. The angle formed is a complementary angle, and the outer peripheral edge of the one slit forming region on the side opposite to the other slit forming region is substantially parallel to the longitudinal direction of the slit. A liquid crystal display device characterized in that the liquid crystal display device is formed.   2. The liquid crystal display device according to claim 1, wherein in each of the pair of slit forming regions, a plurality of slits formed in the electrode on the liquid crystal layer side are formed in parallel to each other.   The said slit is extended to one of the opposing outer periphery of the longitudinal direction of the said slit of the electrode of the said liquid crystal layer side, and the said electrode is made into the comb-tooth shape. Liquid crystal display device.   4. The liquid crystal display device according to claim 1, wherein the pair of slit formation regions are disposed in the pixel. 5.   The liquid crystal display device according to claim 4, wherein an active control unit that controls a voltage applied to the pixel electrode is formed at an outer peripheral edge of the one slit forming region.   The slit forming area adjacent to the other pixel of the one of the pixels adjacent to the slit arrangement direction and the slit forming area adjacent to one of the other pixels are parallel to each other. The liquid crystal display device according to claim 1, wherein the liquid crystal display device is disposed on the liquid crystal display device.   The gate line for supplying a gate signal to a gate of an active control unit that controls a voltage applied to the pixel electrode is disposed at a boundary position between the pair of slit formation regions. Liquid crystal display device.   The liquid crystal display device according to claim 7, wherein the active controller is bent and intersects the gate line twice.

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