JP2007298842A - Liquid crystal display - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent loss of a numerical aperture due to deviation of substrates opposed to each other in a liquid crystal display. <P>SOLUTION: Photo-alignment parallel to a short side of one picture element (PEL) 70 on a TFT substrate side in a plan view is performed in reverse directions in its two sub regions (1) and (2) formed by bisecting the PEL 70 along its long side direction, photo-alignment parallel to the long side of the PEL 70 in a plan view is performed in directions alternately different from each other in three regions of a region [2] formed by uniting two middle regions of divided four regions formed by dividing a color filter 80 on a color filter 80 side equally into four parts along its long side direction, a region [1] and a region [3] which are adjacent to the region [2], a scanning line 2 is disposed so as to be superposed on a boundary 2a between the sub regions (1) and (2) on the PEL 70 side and alignment division lines 9 and 10 are disposed so as to be superposed on a boundary 7a between an upper half part and an lower half part of the sub region (1) and a boundary 8a between an upper half part and a lower half part of the sub region (2), respectively. Even when both substrates deviate from each other, the alignment division lines 9 and 10 on the color filter 80 side are included in the widths of auxiliary capacitance lines 7 and 8 on the PEL 70 side. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a liquid crystal display device, and more particularly to improvement of the aperture ratio.

  In general, a liquid crystal display device is lightweight, thin, and has low power consumption. Therefore, the liquid crystal display device is widely used as a display device for a television, a mobile phone, and the like. Since it is much more advantageous in terms of the above than (CRT), it is rapidly replacing CRT.

  In particular, an active matrix type liquid crystal display device using a thin film transistor (hereinafter also referred to as a TFT (Thin Film Transistor)) as a switching element is excellent in high-speed response and suitable for high definition, and high image quality of a display screen. It is an excellent method for realizing enlargement and color imaging.

  The active matrix liquid crystal display device for color display is a rectangular picture element defined by a signal line and a scanning line that are arranged on a transparent substrate such as glass so as to be partitioned by the signal line and the scanning line. A TFT substrate in which a pixel electrode is formed in the region and a TFT is connected to each of the pixel electrodes, and a common electrode corresponding to the wiring and electrode on the TFT substrate, disposed opposite to the TFT substrate. And the color filter have a configuration in which a liquid crystal layer is sandwiched between a color filter substrate disposed on a transparent substrate such as glass.

  In the TFT substrate, the scanning lines are usually arranged along the horizontal direction of the screen, the signal lines are arranged in the vertical direction so as to intersect with the scanning lines, and are defined by being divided by the scanning lines and the signal lines. In general, the picture element has a rectangular short side along the scanning line and a long side along the signal line.

  An electric field is formed by applying different voltages to the pixel electrode of the TFT substrate and the common electrode of the color filter substrate, thereby changing the alignment of the liquid crystal molecules and adjusting the light transmittance to produce an image. Is displayed.

  An alignment film for controlling the alignment of liquid crystal molecules is laminated on the surface of the TFT substrate and the color filter substrate on the side in contact with the liquid crystal layer so as to cover the electric wirings and the color filter. In such a liquid crystal display device, one of the major development themes is to improve the viewing angle of the display device, that is, to widen the viewing angle.

  There are various approaches for improving the viewing angle. A 4DRTN (4 Domain Reverse Twisted Nematic) mode is one of them, but prior to the description, a conventional RTN (Reverse Twisted Nematic) mode will be described with reference to FIG.

  In this RTN mode, the orientation direction (the direction of the tilde indicated by an arrow in the drawing) in the orientation film of the picture element 40 on the TFT substrate side and the corresponding picture element 50 on the color filter substrate side is the picture element 40, In addition to being parallel to one side of the 50 rectangles, the chilled directions of both substrates are orthogonal to each other. When the liquid crystal layer is sandwiched between such two substrates, the liquid crystal molecules 60 in the layer stand upright in the thickness direction of the layer as shown in FIG. When the electric field is turned on, the liquid crystal is tilted as shown in FIG. 4B, the display is white, and as shown in FIG. 4C, the liquid crystal at the middle position in the thickness direction of the liquid crystal layer sandwiched between the two substrates. When viewed from the normal direction of the substrate, that is, in a plan view, the orientation direction of the molecule 60 is 45 ° with respect to the reference side with respect to one side of the pixel rectangle.

  A conventional VA mode by photo-alignment will be described with reference to FIG. As shown in FIG. 5 (a), each picture element on the TFT substrate side is divided into four regions (subregions) which are cross-cut, and the orientation direction in each subregion is as shown by the arrows in the figure. Make adjacent things different. In each color filter region on the color filter substrate side, as shown in FIG. 5B, the four regions are divided into four regions corresponding to the sub regions on the TFT substrate side. The orientation directions are different from each other. At this time, the orientation direction is opposite between the sub-region on the TFT substrate side and the corresponding region on the color filter substrate side.

  Then, at the middle position in the thickness direction of the liquid crystal layer, as shown in FIG. 5C, with reference to one side of the rectangle of the picture element, 45 °, 135 °, 225 °, 315 ° with respect to that side. Four regions facing the direction of are formed. Due to the presence of the four regions (hereinafter also referred to as domains) having different orientation directions of the liquid crystal molecules, the appearance of the liquid crystal molecules is averaged within the picture element, and the viewing angle is expanded.

  On the other hand, in the 4DRTN mode, an alignment process as shown in FIG. 6 is performed to form such four domains. 6A is a TFT substrate side, and FIG. 6B is a color filter substrate side, each showing one picture element 70 and one corresponding color filter 80 in plan view. In either case, the orientation direction (tilde direction) of the liquid crystal molecules at the position in contact with the alignment film surface is indicated by a thick arrow. Note that the alignment mode on the color filter substrate side shown in FIG. 6B is drawn with the alignment direction seen through the substrate from the surface opposite to the surface on which the alignment film is formed.

  On the TFT substrate side, as shown in FIG. 6A, with respect to the sub-region in which one picture element 70 is divided into two equal parts in the left-right vertical direction, the sub-region on the left side of the drawing is upward, and the sub-region on the right side is downward. Has been subjected to orientation treatment.

  On the color filter substrate side, as shown in FIG. 6B, a region corresponding to one picture element 70 on the TFT substrate side, that is, R (red), G (green), B on the color filter substrate side. A region 80 corresponding to one of (blue) is equally divided in the upper and lower parts of the drawing, and an orientation treatment is applied in the right direction in the divided upper region and in the left direction in the lower region.

  When the liquid crystal layer is sandwiched between the TFT substrate subjected to such an alignment treatment and the color filter substrate, the one close to the TFT substrate is in contact with the alignment film surface of the TFT substrate in the direction of the arrow in FIG. Due to the aligned liquid crystal molecules and those close to the color filter substrate side, the liquid crystal molecules that are in contact with the alignment film surface of the color filter substrate and aligned in the direction of the arrow in FIG. As shown in FIG. 6C, the molecules in the center of the liquid crystal layer in the thickness direction are in a direction of 45 ° with respect to one side of the picture element 70, as the posture propagates sequentially from the adjacent one. Turn to face.

  Then, at an intermediate position in the thickness direction of the liquid crystal layer, when viewed in plan, an area oriented in a direction of 45 ° with respect to one side of the picture element 70 is divided into cross-sections as shown in FIG. Four are formed in the shape. The cross-shaped lines that divide the four regions in plan view are orientation dividing lines, and on the display, black display that does not transmit light is performed. The four regions partitioned by the cross alignment dividing line are domains, and in each of the four domains, the orientation direction of the liquid crystal molecules in the middle position in the thickness direction of the liquid crystal layer corresponds to one side of the rectangle of the pixel 70. Thus, they are oriented at 45 °, 135 °, 225 °, and 315 °.

  Thus, even in the 4DRTN mode, as in the conventional RTN mode, it is possible to obtain four domains in which the orientation of liquid crystal molecules is different in one picture element 70. Since the alignment process is required 8 times for both the substrate and the color filter substrate, the 4DRTN mode has an advantage that the alignment process for each substrate is halved, and the alignment process is only half that time.

  6 (a) and 6 (b), the direction of optical orientation of the picture element 70 of the TFT substrate and the color filter 80 of the color filter substrate (the tilde direction indicated by the arrow in the figure) is an example, and the TFT The substrate side may be along the horizontal direction of the figure, the color filter substrate side may be along the vertical direction of the figure, and so on. It is optional. In short, it is only necessary that the orientation directions of the sub-region on the TFT substrate side and the corresponding region on the color filter substrate side are orthogonal to each other.

  Incidentally, there is photo-alignment as one method of the alignment process. Photo-alignment is performed by, for example, irradiating UV light (ultraviolet rays) from a direction oblique to the normal direction of the surface on which the substrate is aligned, that is, the surface on which the alignment film is formed. The plan view is the arrows in FIGS. 6 (a) and 6 (b). This photo-alignment has an advantage that the substrate is not scratched or dust is not scattered unlike a normal rubbing process.

  When this photo-alignment is performed, in order to change the direction of light irradiation in an adjacent region, a mask is applied to the other region where the photo-orientation is to be performed in a certain direction. Then, in that state, light is applied to one area that is not masked, and then the mask is replaced, and light is irradiated in the opposite direction to the other area that was not previously irradiated with light. .

  By the way, these RTN mode and 4DRTN mode are techniques for improving the viewing angle, but the boundary part of the four domains is different in the direction in which the liquid crystal molecules are tilted and is parallel to the polarization axis (one side of the pixel rectangle). However, since the liquid crystal molecules are tilted at 0 °, 90 °, 180 °, and 270 °, a black display portion (alignment dividing line) that does not transmit light is formed, and there is a disadvantage that the aperture ratio is substantially reduced.

  Here, as in the RTN mode and the 4DRTN mode, the “MVA (multi-domain VA)” method, which is a technique generally used as a technique for obtaining four domains, will be described. In this case, as shown in FIG. 7, the projections 11 zigzag in the direction of 45 ° with respect to the rectangular sides of the picture elements 70 on the surface of the picture elements 70, or electrodes that are electrically equivalent to the projections 11. The notches 12 are formed, and the projections 11 and the notches 12 propagate the forces for tilting the liquid crystal molecules in the directions of 45 °, 135 °, 225 °, and 315 ° to obtain four domains.

  In this method, if the interval between the zigzag formations (the protrusions 11 and the notches 12) is too wide, the propagation efficiency of the force for tilting the liquid crystal molecules decreases, and the liquid crystal molecules cannot be normally tilted. In design, the interval between the formed products must be narrowed. Therefore, the density of the boundary portion between the four domains is increased, and in this case, the aperture ratio is substantially reduced.

  On the other hand, in the RTN mode and the 4DRTN mode, the direction in which the liquid crystal molecules are tilted is guided not by the propagation of the molecular behavior of the liquid crystal molecules but by the pretilt in the alignment film, so the four domains can be designed freely. A liquid crystal display device having a smaller loss of aperture ratio than the “MVA (multi-domain VA)” method can be obtained. However, since an alignment division line for black display is formed, it cannot be denied that the aperture ratio is lowered by this.

  Therefore, when the viewing angle is expanded by the alignment division, the TFT substrate side and the color filter substrate side are suppressed in order to prevent the aperture ratio from being lowered due to the generation of the black alignment division lines as described above. The alignment dividing lines generated in (1) are designed to overlap as much as possible when the two substrates are viewed in plan.

  However, when the TFT substrate and the color filter substrate are combined in the manufacturing process of the liquid crystal display device, if there is a deviation (fitting misalignment) in the direction along the substrate surface, the alignment overlapped on the TFT substrate side and the color filter substrate side. There is a problem in that the dividing line is separated, and the alignment dividing line of the other substrate enters a region where light is originally transmitted on one substrate side, resulting in a loss in aperture ratio. This shift between the TFT substrate and the color filter substrate is difficult to control, and the order of error is large compared to the production of a mask during photo-alignment.

  Therefore, according to the present invention, when an opposing substrate (typically a TFT substrate and a color filter substrate) subjected to alignment processing is combined with each other in an RTN mode or 4DRTN mode liquid crystal display device, the opposing substrates are aligned in the plane direction. It is an object of the present invention to suppress the loss of the aperture ratio that occurs when they are shifted.

In order to achieve the above object, according to the present invention, a rectangular rectangular picture element electrode in which scanning lines and signal lines are arranged vertically and horizontally on the surface of a transparent substrate and TFTs of switching elements are connected is formed in a matrix. A TFT substrate having an alignment film laminated thereon and a counter substrate having an alignment film laminated on the surface of a transparent substrate, the liquid crystal layer between In a liquid crystal display device sandwiching
A short side direction of the rectangular picture element electrode is parallel to the scanning line, and regions having different orientation directions in one picture element are formed by being divided in parallel to the short side of the rectangular picture element by photo-alignment. The configuration is adopted.
Here, the rectangle is cut out in detail from the original pixel electrode in order to avoid the active element portion or to avoid an electrical short circuit between the substrates at the spacer portion that determines the substrate interval. In addition, the present specification simply refers to a rectangle including a case where there is a convex portion.

  At that time, it is possible to employ a configuration in which the irradiation pattern boundary of the photo alignment of the TFT substrate is aligned with a region that does not transmit light when a voltage is applied.

  Furthermore, at that time, it is possible to adopt a configuration in which the irradiation pattern boundary of the photo alignment of the counter substrate is aligned with a region that does not transmit light when a voltage is applied.

  According to such a configuration, for example, with reference to the embodiment shown in FIGS. 1 and 3 in the following embodiment, first, the alignment division line (the black display portion) on the TFT substrate side is overlapped with the scanning line. Originally, it is not affected by the misalignment between the substrates when bonding the substrates, but the alignment division of the boundary between the first and second regions on the side of the color filter substrate that is the opposite substrate The line is above the first auxiliary capacitance line on the TFT substrate side in plan view, and the alignment dividing line at the boundary between the second and third regions is also the second auxiliary capacitance line on the TFT substrate side. Include on top of. This auxiliary capacitance line has a wide width so that it has a coupling capacitance, and even if a shift occurs when fitting the counter substrates, the order of the deviation is absorbed. is there.

  Therefore, even if the misalignment of the two substrates occurs to the extent of the shift order of the two substrates, the alignment dividing line on the color filter substrate side does not enter the transmission region on the TFT substrate side.

  In each of the above configurations, a configuration in which the irradiation direction of the photo alignment and the average alignment direction of the liquid crystal molecules have an angle of 45 ° can be employed.

  By adopting such a configuration, the number of times of light irradiation can be halved, so that the productivity of the product of the present invention is improved.

  A configuration in which the ratio C of the short side to the long side of the rectangular picture element electrode is 1: 3> C ≧ 1: 6 can be adopted.

  Since the present invention is configured as described above, in an active matrix type liquid crystal display device in which alignment division such as 4DRTN mode or RTN mode is performed, the TFT substrate and a counter substrate (for example, a color filter substrate) are fitted. Even if a shift occurs, the alignment dividing line on the counter substrate side does not enter the transmission region (opening region) on the TFT substrate side, and loss of the aperture ratio can be prevented at that point.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1A shows a configuration of electric wiring around one picture element 70 of the TFT substrate of the liquid crystal display device of the present embodiment and a division form of regions having different orientation directions, and FIG. The area of the color filter substrate corresponding to the picture element 70, ie, one color filter 80 such as R (red), G (green), B (blue), etc., is schematically divided into regions with different orientation directions. It is shown. First, the configuration will be described. In the following embodiments, the alignment treatment for the alignment film is based on “photo-alignment”.

  Usually, one picture element of a liquid crystal display device is defined by a vertically long rectangular area partitioned by a signal line arranged in the vertical direction of the display surface and a scanning line arranged in the horizontal direction. In this embodiment, a rectangular pixel defined by a signal line and a scanning line in the normal case is used as a short side of the rectangular shape. A region that has moved by a half of the short side along the long side and has moved by a half of the long side along the long side is defined as a new picture element 70. In the present embodiment, this picture element 70 is used as a reference, and is different from the above-mentioned normal picture element. However, hereinafter, when simply referred to as a picture element, it is the newly defined picture element 70. Say.

  As a result, the signal line 1 of the above-described normal liquid crystal display device has a shape that runs in the center of the short side of the new picture element 70, and the picture element 70 is divided into two halves by the signal line 1. It becomes a shape. In the present embodiment, the pixel electrodes 3 and 4 are formed in the respective regions on both sides of the signal line 1 that is divided into two in the vertical division, and the TFTs 5 and 6 are formed on the respective pixel electrodes 3 and 4. Is connected.

  In addition, according to the form of the picture element 70 of the present embodiment, the scanning line 2 of the present embodiment is not along the short side of the picture element 70 as usual, but the longitudinal center of the picture element 70 is It runs parallel to the short side of the picture element 70. The gate electrode of the TFTs 5 and 6 is connected to the scanning line 2.

  Further, perpendicular to the signal line 1, the reference picture element 70 is arranged in the middle in the longitudinal direction of each reference picture element 70 in the upper and lower regions divided by the scanning line 2, and on the short side of the reference picture element 70. The first and second auxiliary capacitance lines 7 and 8 are arranged in parallel. Both the first and second auxiliary capacitance lines 7 and 8 are wider than the width of the signal line 1 and the scanning line 2 in order to provide a coupling capacitance here.

  The signal line 1, the scanning line 2, and the two auxiliary capacitance lines 7 and 8 naturally correspond to all the picture elements 70 that are adjacent to the reference picture element 70 represented in the figure in the vertical and horizontal directions. In the following, since the configuration related to the picture element 70 represented in this figure is common to all other picture elements 70, the explanation will be made on one picture element 70 in this figure.

  As will be described later, the pixel electrodes 3 and 4 disposed on both sides of the signal line 1 are “R” (red) on the color filter substrate side corresponding to the pixel 70 in one pixel 70. One of the color filters 80 of “G” (green) and “B” (blue) is to be displayed in a bright part and a dark part. In this embodiment, the left side of the signal line 1 in FIG. “Bright part” for bright display and “dark part” for dark display on the right side. Of course, it is arbitrary whether the left and right picture element electrodes 3 and 4 are made to correspond to "bright part" or "dark part".

  The display of the color display of one picture element 70 as “bright part” and “dark part” will be described later. First, the main substrate of the present invention, which is a counter substrate (TFT) at the time of manufacturing a liquid crystal display device. A configuration for preventing a decrease in the aperture ratio based on “fitting misalignment” between the substrate and the color filter substrate) will be described with reference to FIGS.

  In this embodiment, as a form of multi-domain formation for improving the viewing angle, first, as shown in FIG. 1A, on the TFT substrate side, the scanning line 2 that runs in the center in the longitudinal direction of the picture element 70 is used. The picture elements are divided into upper and lower parts of the figure, and each is a sub-region having a different orientation process. Reference numerals (1) and (2) are attached to the upper and lower sub-regions divided by the scanning line 2, respectively.

  Next, on the color filter substrate side, as a multi-domain formation form in one color filter 80 corresponding to one pixel 70 on the TFT substrate side described above, regions having different alignment processes are shown in FIG. The structure is as follows.

  That is, on the way from the upper edge of the color filter 80 to the lower edge along the long side, the position of a quarter of the long side is set as the boundary 9 of the region having a different orientation direction. This boundary coincides with the width center 7a of the first auxiliary capacitance line 7 on the TFT substrate side.

  Then, the next boundary 10 is set at a position that is a half of the long side from the boundary line 9 along the long side of the color filter. This boundary 10 coincides with the width center 8a of the second auxiliary capacitance line 8 on the TFT substrate side.

  The three regions of the color filter 80 divided by the two boundary lines 9 and 10 are denoted by [1] to [3] in order from the top to the bottom of the drawing. Next, FIG. 2 shows the orientation of the above alignment division regions (1), (2) and [1] to [3]. As described at the beginning, the orientation is based on the photo orientation.

  First, on the TFT substrate side, as indicated by an arrow in FIG. 2A, in the subregion (1), an alignment process is performed from the right to the left in the drawing, and in the subregion (2), from the left in the drawing. Alignment processing toward the right is performed.

  On the other hand, the alignment film in the regions [1] to [3] on the color filter substrate side has a direction orthogonal to the alignment direction on the TFT substrate side, as shown by an arrow in FIG. The photo-alignment of the up-down direction is given and the direction is different by [1]-[3].

  In the area [1], the orientation in the plan view is downward, the adjacent [2] is the upward orientation, and the area [3] adjacent to the bottom of [2] The same downward orientation is made. In the area of the color filter 80, the boundaries 9 and 10 of the areas become the alignment dividing lines 9 and 10, and a black line that does not transmit light is displayed on the display.

  In order to fabricate the TFT substrate of (a) and the color filter substrate of (b) configured as described above, first, in the TFT substrate, the signal line 1, the scanning line 2, and the auxiliary capacitance lines 7, 8 are formed on the substrate. After the pixel electrodes 3 and 4 and the TFTs 5 and 6 are formed, and on the color filter substrate side, after forming the common electrode and the color filter 80, each is sensitive to ultraviolet rays such as a polysiloxane material. A vertical alignment film is formed.

  On the TFT substrate side, for example, first, a photomask is applied laterally to the sub-region of (2). Of course, as described above, this photomask is arranged not only for one picture element 70 but also for all picture elements 70 in the row direction adjacent to the left and right and the column direction adjacent vertically. As a result, only the sub-region (1) in (a) is exposed.

  The TFT substrate in this state is irradiated with polarized UV light (ultraviolet rays) obliquely from above and from the right to the left in a plan view. As a result, the (1) sub-region of each picture element 70 is subjected to light orientation in the left direction in plan view.

  Next, the photomask is removed, and the photomask is applied in the lateral direction to the sub-region of (1) of all the picture elements 70 that are first irradiated with UV light. Then, only the sub-region (2) in FIG. 2 (a) is exposed.

  The TFT substrate in this state is irradiated with polarized UV light obliquely from above and in plan view, from left to right in the figure. As a result, the (2) sub-region of each picture element 70 is optically oriented in the right direction in plan view. In this way, a photo-alignment having a pattern as shown in FIG. 2A is finally formed.

  Subsequently, in the same manner, such a mask and light irradiation are performed to form a photo-alignment having a pattern as shown in FIG. 2B on the alignment film of the color filter 80 on the color filter substrate side. Here, FIG. 2A shows the alignment film surface of the TFT substrate as viewed from above, and FIG. 2B shows the alignment film as viewed from the surface opposite to the color filter substrate where the alignment film is formed. It is drawn in the shape of see-through.

  When the TFT substrate and the color filter substrate in which the alignment film is subjected to photo-alignment in the above-described form are sealed with the respective photo-aligned surfaces facing each other and a liquid crystal layer interposed therebetween, the background As described in the technical section, the orientation direction of the liquid crystal molecules at the intermediate position of the liquid crystal layer in one picture element 70 is as shown by a thick arrow in a plan view in FIG. 2C when an electric field is applied. .

  That is, in each of the “bright part” and the “dark part”, the four areas having different orientations of the liquid crystal molecules in plan view are divided into the rectangular areas of the “bright part” and “dark part” in the vertically long direction. It is formed in the shape. The orientation directions of the liquid crystal molecules in these four regions are 45 °, 135 °, 225 °, and 315 ° with respect to one side as a reference of each region. In the case of the present embodiment, the 4DRTN mode is formed in such a form in each of “bright part” and “dark part”. The significance of the formation form of the 4DRTN mode in each of the “bright part” and “dark part” will be described later.

  The object of the present invention is to provide an orientation on the color filter 80 side based on the “fitting misalignment” in the direction along the substrate surface when fitting the two substrates when manufacturing such a 4DTR mode liquid crystal display device. The purpose of this is to prevent the dividing lines 9 and 10 (which are black lines on the display) from entering the light transmission region of the picture element 70 on the TFT substrate side. Description will be made with reference to FIG.

  As shown in FIG. 1A, on the surface on which the alignment film on the TFT substrate side is formed, a boundary line 2a between two sub-regions (1) and (2) in which one picture element 70 is divided into two equal parts. Is an alignment dividing line, and as described above, this is a black display that does not transmit light in display. Therefore, in the TFT substrate, this black display portion is overlapped with the width center 2a of the scanning line 2 that originally does not transmit light to prevent the loss of the opening.

  On the other hand, on the color filter substrate side, the surface of the alignment film of one color filter 80 is divided into three regions labeled [1] to [3] as shown in FIG. The vertical dimension of each of the three divided areas is 1: 2: 1, and the dimension corresponding to “1” is the upper half of (1) obtained by dividing the vertical dimension on the picture element 70 side into four. As already mentioned, it is equal to that of the region. Also in this color filter 80, two boundary lines 9, 10 of [1] and [2] and [2] and [3] are alignment dividing lines, and a black display which does not allow light to pass is displayed. Part.

  Here, the upper sides of the outer shapes of one picture element 70 of the TFT substrate and one color filter 80 of the corresponding color filter substrate are drawn side by side equally. That is, this corresponds to a state in which there is no “displacement” between the two substrates when the substrates are bonded with the surfaces on the alignment film facing each other.

  At this time, the alignment dividing line 9 at the boundary between [1] and [2] on the color filter 80 side is the boundary 7a between the upper half and the lower half of the subregion (1) on the pixel 70 side (indicated by a one-dot chain line). The alignment dividing line 10 at the boundary between [2] and [3] on the color filter 80 side is the boundary 8a (the upper half and the lower half of the subregion (2) on the pixel 70 side. It is on a straight line.

  In other words, the alignment dividing line 9 at the boundary between [1] and [2] on the color filter 80 side is in line with the width center 7a of the first auxiliary capacitance line 7 on the pixel 70 side, and the color filter The alignment dividing line 10 at the boundary between [2] and [3] on the 80 side is in line with the width center 8a of the second auxiliary capacitance line 8 on the pixel 70 side. In the state of FIG. 1, it is assumed that the color filter substrate on the right side of the drawing is shifted downward in the drawing (“shift” is indicated by α in the drawing). That is the state of FIG.

  Referring to FIG. 3, the two alignment division lines 9 and 10 on the color filter 80 side are the same as the first auxiliary capacitance line 7 on the picture element 70 side, even if the color filter substrate and the TFT substrate are displaced. The second auxiliary capacitance line 8 is included in the width direction. In the figure, the first and second auxiliary capacitance lines 7 and 8 of the picture element 70 are extended to the drawing on the color filter 80 side by a two-dot chain line, and the alignment dividing lines 9 and 10 on the color filter 80 side are the first. 1 and the second auxiliary capacitance lines 7 and 8 are included in the width.

  As described above, the first and second auxiliary capacitance lines 7 and 8 are generally set to have a width larger than that of the scanning line 2 in order to have a coupling capacitance here. The width is such that even if a shift occurs in the fitting between the TFT substrate and the color filter substrate, the order of the deviation is absorbed, and the present invention uses this form. .

  Therefore, in the color filter substrate having the alignment division form on the color filter 80 side as shown in FIG. 2B, even if there is a misalignment (deviation: α) between the TFT substrate and the alignment division line 9, 10 is included in the width of the first and second auxiliary capacitance lines 7 and 8 on the picture element 70 side, and does not enter the light transmission region, so that there is no possibility of loss of the aperture ratio.

  On the other hand, the alignment dividing line 2a on the picture element 70 side is formed so as to overlap with the scanning line 2 formed on the TFT substrate, and the scanning line 2 is originally a portion through which light does not pass. The relative “deviation” α does not affect the original aperture ratio.

  Since there is no alignment dividing line in the region [2] on the color filter 80 side corresponding to the scanning line 2 of the TFT substrate or the alignment dividing line 2a superimposed on the scanning line 2, In the area [2], there is no black display element that enters the light transmission area on the TFT substrate side. Thus, in the liquid crystal display device according to the present embodiment to which the present invention is applied, there is no possibility that the aperture ratio is lost even if the “shift” occurs when the TFT substrate and the color filter substrate are fitted. The above configuration corresponds to claim 1 of the present invention.

  Next, each of the picture elements 70, which is one of the configurations of the present embodiment, is divided into two equal parts, and the picture element electrodes 3, 4 corresponding to the two divided areas are respectively divided. Thus, the display of “bright” and “dark” in one picture element 70 will be described.

  The display of “bright” and “dark” in this configuration means “R” (red), “G” (green), and “B” (blue) on the color filter substrate side corresponding to one picture element 70. One of the color filters 80 is displayed with an average brightness with a difference between brightness and darkness, and as a result, a viewing angle relating to “color” when the display surface is viewed obliquely. It tries to improve the dependency.

  Conventionally, in order to divide one picture element 70 into two regions and make one “bright” and the other “dark”, as shown in FIG. Are divided in the long side direction (vertical direction in the figure) to form a “bright part” and a “dark part”. However, in this case, between the picture elements 70 adjacent in the short side direction of the picture element 70, “ A shift of the “optical center of gravity” (indicated by a black circle in the figure) that is the center of the “bright portion” occurs, and the “optical center of gravity” corrugates along the short side direction of the picture element 70 as schematically shown in the figure. The display was blurred.

  Therefore, in this embodiment, the “bright part” and the “dark part” are not divided into upper and lower parts (in the long side direction of the rectangular picture element), but as shown in FIG. In other words, the deviation of the “optical center of gravity” (indicated by a black circle in the figure) is eliminated. When the “bright part” and the “dark part” are divided into left and right, the center of the “bright part” that is the “optical center of gravity” of each picture element is located in the middle of the long side direction of the picture element 70, and the short side direction of the picture element 70 This is because the “optical center of gravity” is not shifted in the short side direction of the picture element 70 and display blur does not occur.

  By the way, even in this vertically divided method, the deviation B of the “optical center of gravity” occurs in the long side direction of the picture element 70, but the degree of the deviation is one third of the deviation A of the “optical center of gravity” in the short side direction. As a whole display device, the degree of display blur can be greatly reduced.

  As an electrical driving method for displaying “bright part” and “dark part” in this vertically divided system, one signal on the scanning line 2 has two kinds of voltages. That is, different voltages are applied to the two auxiliary capacitance lines 7 and 8 so that one is bright and the other is dark.

  The above is a configuration for enlarging the viewing angle by displaying “bright part” and “dark part” in the present embodiment. The orientation modes in the “bright part” and “dark part” are as described above. The significance of the 4DRTN mode alignment process is described.

  The form of the 4DRTN mode is that the four areas generated in each of the “bright part” and “dark part” are four in the long side direction by a boundary line parallel to the short side of each of the “bright part” and “dark part”. The three boundary lines were equally divided, and black display was obtained corresponding to the orientation dividing lines. The reason why the four regions are formed in this manner is that the alignment form as shown in FIG. 2 is adopted.

  However, in order to form four regions with different orientations in each of the “bright part” and “dark part”, the “bright part” and “dark part” are respectively shown in FIGS. 65 (a) and 65 (b). When the orientation processing as shown is performed, the orientation dividing lines in the “bright part” and “dark part” at that time are cross-shaped as shown in FIG. The total length of the black display by the cross shape is the sum of the vertical dimension and the horizontal dimension of each of “bright part” and “dark part”.

  On the other hand, when the alignment process as in the present embodiment is adopted, the alignment dividing lines in the “bright part” and the “dark part” are parallel to the rectangular short sides of the “bright part” and the “dark part”. The total length of the alignment dividing lines for black display is only three times the short side, and this length is shorter than the total length of the cross-shaped black display. That is, the loss of the aperture ratio is smaller in the orientation processing mode of the present embodiment.

  Further, as compared with the case where the alignment is divided into the ten o'clock shape, the loss of transmittance that occurs when the TFT substrate and the counter substrate are bonded to each other is small, and the effect of the present invention is further exhibited. In this configuration, the ratio C between the short side and the long side of the rectangular pixel electrode is 1: 3> C ≧ 1: 6, which corresponds to claim 5 of the present invention.

  The present invention is widely applicable to active matrix liquid crystal display devices in general, and liquid crystal televisions or liquid crystal monitors provided with the active matrix liquid crystal display devices.

(A) shows the configuration of the electrical wiring around one picture element of the TFT substrate of the liquid crystal display device of the present embodiment and the division form of the region for forming the photo-alignment, and (b) shows the picture element. FIG. 3 schematically shows a division form of a region for forming a photo-alignment for one color filter on the corresponding color filter substrate side. (A) and (b) are patterns of photo-alignment treatment for both substrates for generating the 4DRTN mode in this embodiment, respectively, and (c) is a liquid crystal layer between both substrates based on the photo-alignment treatment. It is the top view which showed typically the orientation pattern of the liquid crystal molecule of an intermediate position. These are the schematic diagrams which showed the advantage of this embodiment. These are the perspective views which showed typically the mode of the orientation of the liquid crystal in a RTN mode in the state of an electric field off in (a), and the state of an electric field on in (b). Shows the pattern of the photo-alignment treatment for both substrates for VA mode generation by the conventional photo-alignment, respectively in (a) and (b), and (c) shows the liquid crystal based on the processes of (a) and (b). The alignment state of the liquid crystal molecules at the middle position in the layer thickness direction is schematically shown in plan view. (A) and (b) show patterns of photo-alignment processing for both substrates for generating 4DRTN mode, respectively, and (c) shows a liquid crystal layer thickness direction intermediate position based on the processing of (a) and (b). The alignment state of the liquid crystal molecules is schematically shown in plan view. Fig. 4 schematically shows the MVA method. FIG. 9A and FIG. 9B schematically show the fluctuation of the “optical center of gravity” in each of FIGS.

Explanation of symbols

1 signal line 2 scanning line 2a boundary (width center of scanning line)
3, 4 Pixel electrode 5, 6 TFT
7 first auxiliary capacitance line 8 second auxiliary capacitance line 7a, 8a boundary line (width center of auxiliary capacitance line)
9, 10 Orientation dividing line 11 Protrusion 12 Notch 70 Picture element 80 Color filter α Relative shift amount of the counter substrate (color filter substrate) with respect to the TFT substrate

Claims (6)

Scanning lines and signal lines cross vertically and horizontally on the surface of a transparent substrate, rectangular pixel electrodes connected with TFTs of switching elements are arranged in a matrix, and alignment films are stacked to cover them. A TFT substrate,
A counter substrate in which an alignment film is laminated on the surface of the transparent substrate,
In the liquid crystal display device in which the surface on which the alignment film is formed is opposed and the liquid crystal layer is sandwiched therebetween,
A short side direction of the rectangular picture element electrode is parallel to the scanning line, and regions having different orientation directions in one picture element are formed by being divided in parallel to the short side of the rectangular picture element by photo-alignment. A liquid crystal display device.   2. The liquid crystal display device according to claim 1, wherein the irradiation pattern boundary of the photo alignment of the TFT substrate is aligned with a region that does not transmit light when a voltage is applied.   3. The liquid crystal display device according to claim 2, wherein an irradiation pattern boundary of the photo alignment of the counter substrate is aligned with a region that does not transmit light when a voltage is applied.   2. The liquid crystal display device according to claim 1, wherein the photo-alignment irradiation direction and the average alignment direction of the liquid crystal molecules have an angle of 45 [deg.].   5. The liquid crystal display device according to claim 1, wherein a ratio C of a short side to a long side of the rectangular picture element electrode is 1: 3> C ≧ 1: 6.   A liquid crystal television or a liquid crystal monitor comprising the liquid crystal display device according to claim 1.

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