Patent Publication Number: US-2023161204-A1

Title: Display device

Description:
CROSS REFERENCES TO RELATED APPLICATIONS 
     The present application is a continuation of U.S. patent application Ser. No. 16/586,169, filed on Sep. 27, 2019, which is a continuation of U.S. patent application Ser. No. 15/387,141, filed on Dec. 21, 2016, issued as U.S. Pat. No. 10,429,705 on Oct. 1, 2019, which application is a continuation of U.S. patent application Ser. No. 14/919,047, filed on Oct. 21, 2015, issued as U.S. Pat. No. 9,551,909 on Jan. 24, 2017, which application is a continuation of U.S. patent application Ser. No. 12/642,312, filed on Dec. 18, 2009, issued as U.S. Pat. No. 9,195,102 on Nov. 24, 2015, which application claims priority to JP 2008-324779 filed in the Japan Patent Office on Dec. 19, 2008, the entire contents of which is hereby incorporated by reference. 
    
    
     BACKGROUND 
     The present application relates to a transverse electric field driving liquid crystal panel which performs rotation control of the arrangement of liquid crystal molecules in parallel to a substrate surface by a transverse electric field generated between a pixel electrode and a counter electrode. The present application also relates to an electronic apparatus having the liquid crystal panel mounted therein. 
     At present, liquid crystal panels have various panel structures corresponding to various driving methods including a vertical electric field display type in which an electric field is generated in the vertical direction with respect to the panel surface. For example, a transverse electric field display type panel structure is suggested in which an electric field is generated in the horizontal direction with respect to the panel surface. 
     In the transverse electric field display type liquid crystal panel, the rotation direction of liquid crystal molecules is parallel to the substrate surface. That is, in the transverse electric field display type liquid crystal panel, there is little rotation of the liquid crystal molecules in the vertical direction with respect to the substrate surface. For this reason, changes in the optical characteristics (contrast, luminance, and color tone) are comparatively small. That is, the transverse electric field display type liquid crystal panel has a wider viewing angle than the vertical electric field display type liquid crystal panel. 
       FIG.  1    shows an example of the sectional structure of a pixel region constituting a transverse electric field display type liquid crystal panel.  FIG.  2    shows an example of the corresponding planar structure. 
     A liquid crystal panel  1  has two glass substrates  3  and  5 , and a liquid crystal layer  7  filled so as to be sandwiched with the glass substrates  3  and  5 . A polarizing plate  9  is disposed on the outer surface of each substrate, and an alignment film  11  is disposed on the inner surface of each substrate. Note that the alignment film  11  is used to arrange a group of liquid crystal molecules of the liquid crystal layer  7  in a predetermined direction. In general, a polyimide film is used. 
     On the glass substrate  5 , a pixel electrode  13  and a counter electrode  15  are formed of a transparent conductive film. Of these, the pixel electrode  13  is structured such that both ends of five comb-shaped electrode branches  13 A are respectively connected by connection portions  13 B. At the upper end of the pixel electrode  13  in  FIG.  2   , a rectangular contact portion  13 C is formed so as to be connected integrally to part of the electrode branches  13 A and the connection portion  13 B. 
     Meanwhile, the counter electrode  15  is formed below the electrode branches  13 A (near the glass substrate  5 ) so as to cover the entire pixel region. This electrode structure causes a parabolic electric field between the electrode branches  13 A and the counter electrode  15 . In  FIG.  1   , this electric field is indicated by a dotted-line arrow. 
     The pixel region corresponds to a region surrounded by signal lines  21  and scanning lines  23  shown in  FIG.  2   . In each pixel region, a thin film transistor for controlling the application of a signal potential to the pixel electrode  13  is disposed. The gate electrode of the thin film transistor is connected to a scanning line  23 , so the thin film transistor is turned on/off by the potential of the scanning line  23 . 
     One main electrode of the thin film transistor is connected to a signal line  21  through an interconnect pattern (not shown), and the other main electrode of the thin film transistor is connected to a contact  25 . Thus, when the thin film transistor is turned on, the signal line  21  and the pixel electrode  13  are electrically connected to each other. 
     As shown in  FIG.  2   , in this specification, a gap between the electrode branches  13 A is called a slit  31 . In  FIG.  2   , the extension direction of the slit  31  is identical to the extension direction of the signal line  21 . That is, the slit  31  is formed along the Y-axis direction of  FIG.  2   . 
     For reference,  FIGS.  3 A and  3 B  show the sectional structure around the contact  25 . 
     JP-A-10-123482 and JP-A-11-202356 are examples of the related art. 
     SUMMARY 
     In the transverse electric field display type liquid crystal panel, it is known that, as shown in  FIG.  4   , the alignment of the liquid crystal molecules is likely to be disturbed at both ends of the slit  31  (around the connection portion of the electrode branches  13 A and the connection portion  13 B or the contact  13 C). This is because the contact portion serves as a rectangular electrode, so no transverse electric field is generated and weak alignment control is performed. Further, the portion around the contact is quite uneven, so this portion causes disturbance of alignment. This phenomenon is called disclination. 
     In  FIG.  4   , regions  41  where the above-described disclination is likely to occur are shaded. In  FIG.  4   , the alignment of the liquid crystal molecules is disturbed at eight regions  41  in total. 
     If external pressure (finger press or the like) is applied to the disclination, as indicated by an arrow in the drawing, the disturbance of the arrangement of the liquid crystal molecules is expanded along the extension direction of the electrode branches  13 A. Note that the disturbance of the arrangement of the liquid crystal molecules is applied such that the arrangement of the liquid crystal molecules is rotated in a direction opposite to the electric field direction. This phenomenon is called a reverse twist phenomenon. 
       FIG.  5    shows an example of the occurrence of a reverse twist phenomenon. In  FIG.  5   , regions  43  where the arrangement of the liquid crystal molecules is disturbed are shaded. These regions extend along the extension direction of the electrode branches  13 A. 
     In the case of the liquid crystal panel being used at present, if the reverse twist phenomenon occurs, the original state is not restored after it has been left uncontrolled. This is because the disclination expanded from the upper portion of the pixel is linked with the disclination expanded from the lower portion of the pixel at the central portion of the pixel to form a stabilized state, and the alignment direction of the liquid crystal molecules in the regions  43  is not restored to the original state. As a result, the regions  43  where the reverse twist phenomenon occurs may be continuously viewed as residual images (that is, display irregularity). Hereinafter, the residual image is called a reverse twist line. 
     Accordingly, a reverse twist line is likely to remain in two electrode branches  13 A directly extending from the contact portion  13 C. In  FIG.  5   , two reverse twist lines at the central portion of the pixel region are emphasized over reverse twist lines on both sides. 
     An embodiment provides a liquid crystal panel. The liquid crystal panel includes first and second substrates arranged to be opposite each other at a predetermined gap, a liquid crystal layer filled between the first and second substrates, alignment films, a counter electrode pattern formed on the first substrate, and a pixel electrode pattern formed on the first substrate so as to have a plurality of electrode branches, the pixel electrode pattern having a partial connection branch formed around a contact so as to transversely connect a plurality of electrode branches extending from the contact from among the plurality of electrode branches. 
     The pixel electrode pattern and the counter electrode pattern may be formed on the same layer surface, or may be formed on different layer surfaces. That is, if the liquid crystal panel is a transverse electric field display type liquid crystal panel, and the pixel electrode has a slit, the sectional structure of the pixel region is not limited. 
     The cross angle between the extension direction of each slit formed by the plurality of electrode branches constituting the pixel electrode pattern and the alignment direction of liquid crystal may be equal to or larger than 7°. 
     As described above, the partial connection branch is formed in the region around the contact with weak alignment stability so as to transversely connect a plurality of electrode branches. Therefore, even though liquid crystal is pressed down by external pressure, disclination which occurs in the region around the contact can be prevented from growing toward the center of the pixel along the electrode branches so as to be confined between the region around the contact and the partial connection branch. As a result, the occurrence of display irregularity (reverse twist line) due to external pressure can be minimized. 
     Additional features and advantages are described herein, and will be apparent from the following Detailed Description and the figures. 
    
    
     
       BRIEF DESCRIPTION OF THE FIGURES 
         FIG.  1    is a diagram illustrating an example of the sectional structure of a transverse electric field display type liquid crystal panel. 
         FIG.  2    is a diagram illustrating an example of the planar structure of a transverse electric field display type liquid crystal panel. 
         FIGS.  3 A and  3 B  are diagrams showing an example of the sectional structure around a contact. 
         FIG.  4    is a diagram illustrating disclination. 
         FIG.  5    is a diagram illustrating a reverse twist phenomenon. 
         FIG.  6    is a diagram showing an appearance example of a liquid crystal panel module. 
         FIG.  7    is a diagram showing an example of the system configuration of a liquid crystal panel module. 
         FIG.  8    is a diagram showing a first pixel structure example (planar structure). 
         FIG.  9    is a diagram illustrating an occurrence example of a reverse twist line. 
         FIG.  10    is a diagram showing a second pixel structure example (planar structure). 
         FIG.  11    is a diagram illustrating the relationship between the magnitude of a cross angle and display irregularity disappearance time. 
         FIG.  12    is a diagram illustrating the relationship between the magnitude of a cross angle and the level of display irregularity. 
         FIG.  13    is a diagram illustrating the relationship between the magnitude of a cross angle and relative transmittance. 
         FIG.  14    is a diagram showing a third pixel structure example (planar structure). 
         FIG.  15    is a diagram showing a fourth pixel structure example (planar structure). 
         FIG.  16    is a diagram showing a fifth pixel structure example (sectional structure). 
         FIG.  17    is a diagram showing a sixth pixel structure example (sectional structure). 
         FIG.  18    is a diagram showing the sixth pixel structure example (planar structure). 
         FIG.  19    is a diagram showing a seventh pixel structure example (planar structure). 
         FIG.  20    is a diagram illustrating the system configuration of an electronic apparatus. 
         FIG.  21    is a diagram showing an appearance example of an electronic apparatus. 
         FIGS.  22 A and  22 B  are diagrams showing an appearance example of an electronic apparatus. 
         FIG.  23    is a diagram showing an appearance example of an electronic apparatus. 
         FIGS.  24 A and  24 B  are diagrams showing an appearance example of an electronic apparatus. 
         FIG.  25    is a diagram showing an appearance example of an electronic apparatus. 
         FIG.  26    is a diagram showing a first and second pixel structure example (planar structure). 
     
    
    
     DETAILED DESCRIPTION 
     The present application will be described as follows with reference to the drawings according to an embodiment. 
     (A) Appearance Example of Liquid Crystal Panel Module and Panel Structure 
     (B) Pixel Structure Example 1: Single Domain Structure 
     (C) Pixel Structure Example 2: Pseudo Dual Domain Structure 
     (D) Pixel Structure Example 3: Dual Domain Structure 
     (E) Pixel Structure Example 4: Dual Domain Structure 
     (F) Pixel Structure Example 5: Different Sectional Structure 
     (G) Pixel Structure Example 6: Different Sectional Structure 
     (H) Pixel Structure Example 7: Different Pixel Structure Example 
     (I) Other Examples 
     Elements which are not provided with particular drawings or descriptions herein are realized by existing techniques in the relevant technical field. Embodiments described below are only exemplary, and the application is not limited thereto. 
     (A) Appearance Example of Liquid Crystal Panel Module and Panel Structure 
       FIG.  6    shows an appearance example of a liquid crystal panel module  51 . The liquid crystal panel module  51  is structured such that a counter substrate  55  is bonded to a support substrate  53 . The support substrate  53  is made of glass, plastic, or other substrates. The counter substrate  55  is also made of glass, plastic, or other transparent substrates. The counter substrate  55  is a member which seals the surface of the support substrate  53  with a sealant interposed therebetween. 
     Note that only one substrate on the light emission side may be a transparent substrate, and the other substrate may be a nontransparent substrate. 
     Further, the liquid crystal panel  51  is provided with an FPC (Flexible Printed Circuit)  57  for inputting an external signal or driving power, if necessary. 
       FIG.  7    shows an example of the system configuration of the liquid crystal panel module  51 . The liquid crystal panel module  51  is configured such that a pixel array section  63 , a signal line driver  65 , a gate line driver  67 , and a timing controller  69  are disposed on a lower glass substrate  61  (corresponding to the glass substrate  5  of  FIG.  1   ). In this embodiment, the driving circuit of the pixel array section  63  is formed as a single or a plurality of semiconductor integrated circuits, and is mounted on the glass substrate. 
     The pixel array section  63  has a matrix structure in which white units each constituting one pixel for display are arranged in M rows×N columns. In this specification, the row refers to a pixel row of 3×N subpixels  71  arranged in the X direction of the drawing. The column refers to a pixel column of M subpixels  71  arranged in the Y direction of the drawing. Of course, the values M and N are determined depending on the display resolution in the vertical direction and the display resolution in the horizontal direction. 
     The signal line driver  65  is used to apply a signal potential Vsig corresponding to a pixel gradation value to signal lines DL. In this embodiment, the signal lines DL are arranged so as to extend in the Y direction of the drawing. 
     The gate line driver  67  is used to apply control pulses for providing the write timing of the signal potential Vsig to scanning lines WL. In this embodiment, the scanning lines WL are arranged so as to extend in the X direction of the drawing. 
     A thin film transistor (not shown) is formed in each subpixel  71 . The thin film transistor has a gate electrode connected to a corresponding one of the scanning lines WL, one main electrode connected to a corresponding one of the signal lines DL, and the other main electrode connected to the pixel electrode  13 . 
     The timing controller  69  is a circuit device which supplies driving pulses to the signal line driver  65  and the gate line driver  67 . 
     (B) Pixel Structure Example 1 
       FIG.  8    shows a pixel structure example. This pixel structure is used in an FFS (Fringe Field Switching) type liquid crystal panel. 
     Thus, the sectional structure of the pixel region is the same as shown in  FIG.  1   . That is, the counter electrode  15  is disposed below the pixel electrode  13  so as to cover the entire pixel region. 
     The pixel structure shown in  FIG.  8    has the same basic structure as the pixel structure shown in  FIG.  2   . That is, the pixel electrode  13  is structured such that both ends of comb-shaped five electrode branches  13 A are respectively connected to each other by connection portions  13 B. 
     The pixel electrode  13  has a contact portion  13 C at the upper end of the pixel region in the drawing. The contact portion  13 C is connected to the thin film transistor (not shown) through a contact  25  formed at the central portion thereof. 
     One end of the contact portion  13 C is connected to the connection portion  13 B, and the other end of the contact portion  13 C is connected to three electrode branches  13 A. 
     The three electrode branches  13 A are electrode branches  13 A other than two electrode branches  13 A at both ends from among the five electrode branches  13 A. 
     The contact portion  13 C has a large pattern area. For this reason, at the boundary between the contact portion  13 C and two slits  31  which are formed by the three electrode branches  13 A directly connected to the contact portion  13 C, alignment stability is likely to be weakened. The weak alignment stability means that reverse twist which occurs when liquid crystal is pressed down is likely to grow. 
     Accordingly, in the pixel structure example of  FIG.  8   , a partial connection branch  81  is formed around the contact portion  13 C so as to transversely connect the three electrode branches  13 A directly extending from the contact portion  13 C. With this partial connection portion  81 , the two slits  31  formed by the three electrode branches  13 A at the central portion of the pixel region can be physically divided into two regions. 
     The two slits  31  are slits where the growth of reverse twist is likely to dominantly appear when liquid crystal is pressed down. 
     However, with the partial connection branch  81 , even though liquid crystal is pressed down, the growth of the reverse twist can be confined within the slit  31  on the contact portion  13 C side and can be prevented from reaching around the center of the pixel region.  FIG.  9    shows a state where liquid crystal is pressed down due to external pressure. 
     As will be understood from the comparison of  FIGS.  9  and  5   , in the pixel region where the partial connection branch  81  is formed, a reverse twist line which remains in the pixel region is significantly reduced. In particular, a reverse twist line which occurs around the center of the pixel region can be eliminated or significantly reduced. 
     As a result, with this pixel structure, the display quality can be significantly improved over the liquid crystal panel. 
     It is preferable that the space formed between the contact portion  13 C and the partial connection branch  81  is as small as possible. For example, the space is preferably small to be close to the manufacturing limit. This is because, the narrower the space, the more the area of the pixel region to which the alignment regulation force is applied can be increased. 
     Similarly, it should suffice that the partial connection branch  81  can divide the region into two parts, so the pattern width of the partial connection branch  81  is preferably thin to be close to the manufacturing limit. 
     (C) Pixel Structure Example 2 
       FIG.  10    shows a second pixel structure example. It is assumed that this pixel structure example is also used in an FFS (Fringe Field Switching) type liquid crystal panel. 
     The pixel electrode  13  has the same basic pattern structure as the above-described pixel structure example ( FIG.  8   ). That is, the pixel electrode  13  has five electrode branches  13 A, a connection portion  13 B, a contact portion  13 C, and a partial connection branch  81 . 
     Meanwhile, in the above-described pixel structure example ( FIG.  8   ), the case where the signal lines  21  and the electrode branches  13 A are formed in parallel to the Y-axis direction has been described. 
     The pixel structure example of  FIG.  10    is different from the above-described pixel structure example in that the wirings in the pixel region are formed so as to be inclined with respect to the Y-axis direction. 
     The inclination direction is inverted between two upper and lower pixel regions arranged in the Y-axis direction. That is, a pattern which is inclined in the clockwise direction with respect to the Y-axis direction and a pattern which is inclined in the counterclockwise direction with respect to the Y-axis direction are alternately disposed along the Y-axis direction. In other words, the pixel regions in this embodiment have a vertical mirror structure with respect to the scanning line  23  extending in the X-axis direction. 
       FIG.  10    mainly shows a case where the pattern of the pixel region is inclined in the clockwise direction with respect to the Y-axis direction. The alignment direction of the alignment film  11  is parallel to the Y-axis direction. Therefore, in this pixel region, the liquid crystal molecules rotate in the counterclockwise direction by the application of an electric field. 
     Of course, a pixel region where the pattern in the pixel region is inclined in the counterclockwise direction with respect to the Y-axis direction is formed above and below the pixel region shown in  FIG.  10   . In this region, the liquid crystal molecules rotate in the clockwise direction by the application of an electric field. 
     As described above, the rotation direction of the liquid crystal molecules is inverted between the two upper and lower pixel regions, so a liquid crystal panel with a wide viewing angle can be realized. 
     The above-described pixel structure constitutes a pseudo dual domain structure. 
     Hereinafter, the preferable relationship between the alignment direction of the liquid crystal layer  7  and the extension direction of each slit  31  formed by the electrode branches  13 A will be described. Note that the alignment direction of the liquid crystal layer  7  (also referred to as “alignment direction of liquid crystal”) is defined by the orientation of dielectric anisotropy of liquid crystal, and refers to a direction with a large dielectric constant. 
     In the pixel structure of  FIG.  10   , a case where the cross angle α between the alignment direction of the liquid crystal layer  7  and the extension direction of each slit  31  formed by the electrode branches  13 A is equal to or larger than 7° is shown as a preferred structure. 
     This value is determined by the following experiment. Hereinafter, the characteristics confirmed by the inventors will be described. 
       FIG.  11    shows the characteristics which are recognized between the extension direction of the slit  31  and the alignment direction of the liquid crystal layer  7 .  FIG.  11    shows the relationship between the cross angle α and the time until display irregularity disappears. In  FIG.  11   , the horizontal axis denotes the cross angle α between the extension direction of the slit  31  and the alignment direction of the liquid crystal layer  7 , and the vertical axis denotes the time until display irregularity disappears. 
     From the experiment result shown in  FIG.  11   , when the cross angle α is smaller than 7°, it has been confirmed that display irregularity due to the reverse twist phenomenon does not disappear by itself. 
     Meanwhile, when the cross angle α is equal to or larger than 7°, it has been confirmed that display irregularity due to the reverse twist phenomenon can disappear by itself. For this reason, in  FIG.  10   , the cross angle α is shown to be equal to or larger than 7°. 
     When the cross angle α is 7°, the time until display irregularity disappears is 3.5 [seconds]. The experiment shows that, as the cross angle α becomes larger, the time until display irregularity disappears is shortened. 
     For example, when the cross angle α is 10°, it has been confirmed that display irregularity disappears in 3 [seconds]. When the cross angle α is 15°, it has been confirmed that display irregularity disappears in 2.5 [seconds]. When the cross angle α is 20°, it has been confirmed that display irregularity disappears in 1.5 [seconds]. 
     From this, it can be seen that, as the cross angle α becomes larger, the alignment regulation force of the liquid crystal molecules in the transverse electric field display type liquid crystal panel can be increased. 
       FIG.  12    shows the observation result regarding the relationship between the cross angle α and the level of display irregularity. In  FIG.  12   , the horizontal axis denotes the cross angle α between the extension direction of the slit  31  and the alignment direction of the liquid crystal layer  7 , and the vertical axis denotes the visible level of display irregularity. 
     As shown in  FIG.  12   , if the cross angle α is equal to or larger than 10°, it has been confirmed that no display irregularity is observed even when the display screen is viewed at any angle. When the cross angle α is 5°, it has been confirmed that, when the display screen is viewed from an oblique direction, slight display irregularity is observed. When the cross angle α is equal to or larger than 5° and smaller than 10°, as shown in  FIG.  12   , it has been confirmed that visibility is gradually changed. 
     However, the larger cross angle α is not necessarily the better. 
       FIG.  13    shows the confirmed transmission characteristics. In  FIG.  13   , the horizontal axis denotes the cross angle α between the extension direction of the slit  31  and the alignment direction of the liquid crystal layer  7 , and the vertical axis denotes relative transmittance. In  FIG.  13   , it is assumed that, when the cross angle α is 5°, the relative transmittance is 100%. 
     In  FIG.  13   , when the cross angle α is 5°, the maximum transmittance is obtained, and when the cross angle α is 45°, the minimum transmittance is obtained. Note that, when the cross a is 45°, the relative transmittance is about 64%. 
     As shown in  FIG.  13   , it has been seen that the cross angle α and the relative transmittance have a roughly linear relationship. From the viewpoint of transmittance, it can be seen that, as the cross angle α is smaller, better display luminance is obtained. 
     From the above-described characteristics, the inventors have considered it preferable that the cross angle α between the extension direction of the slit  31  and the alignment direction of the liquid crystal layer  7  be equal to or larger than 7° and equal to or smaller than 15°. If this condition is satisfied, the relative transmittance and the time until display irregularity disappears can be maintained appropriately. 
     Therefore, a liquid crystal panel can be realized in which, even though the reverse twist phenomenon due to finger press or the like disturbs the arrangement of the liquid crystal molecules, the disturbance can be eliminated by itself in several seconds. 
       FIG.  26    shows another pixel structure example where the pixel electrode  13  has the same basic pattern structure as in examples described above where a first pixel electrode  13  and a second pixel electrode  13  respectively have one or more slits  31  inclined in a different direction from each other (e.g., clockwise and counter-clockwise). 
     (D) Pixel Structure Example 3 
       FIG.  14    shows a third pixel structure example. This pixel structure is also used in an FFS (Fringe Field Switching) type liquid crystal panel. 
     However, in the third pixel structure, each pixel region has a dual domain structure. That is, the pixel electrode  13  is bent around the center of the pixel region (in the drawing, a rectangular region indicated by a broken line) in the Y-axis direction. 
     In  FIG.  14   , one bend point is provided, but two or more bend points may be provided to form a multi-domain structure. 
     The pixel structure shown in  FIG.  14    has a vertical mirror structure along a virtual line extending along the X-axis direction from the bend point. One contact portion  13 C and one partial connection branch  81  are provided in the pixel region. Therefore, the contact portion  13 C and partial connection branch  81  are not included in the vertical mirror structure. The vertical mirror structure includes the signal line  21  as well as the pixel electrode  13 . 
     Under this condition, the cross angle α between the alignment direction of the liquid crystal layer  7  and the extension direction of the slit  31  is set to be equal to or larger than 7°. Of course, from the viewpoint of display performance, it is preferable that the cross angle α is equal to or larger than 7° and smaller than 15°. Further, it is assumed that the alignment direction of the liquid crystal layer  7  is parallel to the Y-axis direction. 
     In the case of the pixel structure with a dual domain structure, the rotation direction of the liquid crystal molecules is inverted between the upper half portion and the lower half portion of the pixel region. That is, while the liquid crystal molecules in the upper half portion of the pixel region of the drawing rotate in the counterclockwise direction by the application of an electric field, and the liquid crystal molecules in the lower half portion of the pixel region of the drawing rotate in the clockwise direction by the application of an electric field. 
     As described above, the rotation direction of the liquid crystal molecules is inverted, so the amount of light per pixel can be made uniform even when the display screen is viewed at any angle. Therefore, a liquid crystal panel with a wider viewing angle than the first pixel structure can be realized. 
     Of course, as described above, the relationship between the alignment direction of the liquid crystal layer  7  and the extension direction of the slit  31  is optimized. Therefore, even though the reverse twist due to finger press or the like disturbs the arrangement of the liquid crystal molecules, the disturbance can be eliminated by itself in several seconds. 
     (E) Pixel Structure Example 4 
       FIG.  15    shows a fourth pixel structure example. This pixel structure corresponds to a modification of the dual domain structure shown in  FIG.  14   . That is, the pixel structure shown in  FIG.  15    corresponds to a pixel structure in which each pixel has a dual domain structure, and has the same basic pixel structure as the pixel structure shown in  FIG.  14   . 
     A difference is that a connection branch  13 D is additionally provided so as to transversely connect the bend points of the electrode branches  13 A to each other. 
     The reason is as follows. In the third pixel structure of  FIG.  14   , the rotation direction of the liquid crystal molecules is inverted at the boundary between the domains (a portion around the bend point). For this reason, the alignment regulation force is weakened at the boundary, which causes alignment disturbance. The alignment disturbance may adversely affect the disappearance of the reverse twist line phenomenon. 
     Meanwhile, in the pixel structure example of  FIG.  15   , two domains can be physically separated from each other by the connection branch  13 C which connects all the five electrode branches  13 A at the bend points. 
     For this reason, it is possible to eliminate disturbance of the arrangement of the liquid crystal molecules at the boundary between the domains. As a result, with the pixel structure shown in  FIG.  15   , the time until the reverse twist line disappears can be further shortened, as compared with the pixel structure shown in  FIG.  14   . 
     (F) Pixel Structure Example 5 
     In the above-described four pixel structure examples, the FFS type liquid crystal panel having the sectional structure described with reference to  FIG.  1    has been described. That is, a liquid crystal panel has been described which has a pixel structure in which the counter electrode  15  is disposed below the comb-shaped pixel electrode  13  so as to cover the entire pixel region. 
     Alternatively, as shown in  FIG.  16   , a liquid crystal panel  91  having a comb-shaped counter electrode  15  may be adopted. In  FIG.  16   , the corresponding elements to those in  FIG.  1    are represented by the same reference numerals. 
     In  FIG.  16   , the electrode branches  15 A of the counter electrode  15  are disposed so as to fill the spaces (slits  31 ) between the electrode branches  13 A of the pixel electrode  13 . 
     That is, the electrode branches  15 A of the counter electrode  15  are disposed so as not to overlap the electrode branches  13 A of the pixel electrode  13  in the pixel region. Of course, there is no difference in the electric field formed between the pixel electrode  13  and the counter electrode  15 . 
     (G) Pixel Structure Example 6 
     In the above-described pixel structure examples, the description has been made of the pixel structure in which the pixel electrode  13  and the counter electrode  15  are formed in different layers. 
     Alternatively, the technique which has been suggested by the inventors may also be applied to a transverse electric field display type liquid crystal panel in which the pixel electrode  13  and the counter electrode  15  are formed in the same layer. 
       FIG.  17    shows a sectional structure example corresponding to a sixth pixel structure example.  FIG.  18    shows a planar structure example corresponding to the sixth pixel structure example. Note that the liquid crystal panel has the same basic structure as the liquid crystal panel with a different pixel structure. 
     That is, the liquid crystal panel  101  includes two glass substrates  3  and  5 , and a liquid crystal layer  7  filled so as to be sandwiched with the glass substrates  3  and  5 . A polarizing plate  9  is disposed on the outer surface of each substrate, and an alignment film  11  is disposed on the inner surface of each substrate. 
     In the liquid crystal panel  101  of  FIG.  17   , the pixel electrode  13  and the counter electrode  15  are formed on the glass substrate  5 . 
     Of these, the pixel electrode  13  is structured such that one ends of comb-shaped four electrode branches  13 A are connected to each other by a connection portion  13 B. 
     Meanwhile, the counter electrode  15  in the pixel region is comb-shaped, similarly to  FIG.  16   . In  FIG.  17   , three electrode branches  15 A are formed in the pixel region, and one end of each electrode branch  15 A is connected to a common electrode line  33 . In this case, the electrode branches  15 A of the counter electrode  15  are formed in the same layer as the pixel electrode  13  so as to be fitted into the spaces between the electrode branches  13 A of the pixel electrode  13 . The common electrode line  33  is formed in a lattice shape so as to follow the signal lines  21  and the scanning lines  23 , as shown in  FIG.  18   . 
     As described above, in this pixel structure example, the electrode branches  13 A of the pixel electrode  13  and the electrode branches  15 A of the counter electrode  15  are disposed in the same layer so as to alternately appear in the X-axis direction. With this electrode structure, a parabolic electric field is generated between the electrode branches  13 A of the pixel electrode  13  and the electrode branches  15 A of the counter electrode  15 . In  FIG.  17   , this electric field is indicated by a broken line. 
     As shown in  FIG.  18   , in this pixel structure example, two electrode branches  13 A directly extend from the contact portion  13 C. Therefore, in this pixel structure, a partial connection branch  81  is formed so as to connect the two electrode branches  13 A to each other. 
     With this pixel structure, a liquid crystal panel can be realized in which a reverse twist line is unlikely to occur around the center of the pixel region due to external pressure, such as finger press or the like. 
     (H) Pixel Structure Example 7 
     In the above-described six pixel structure examples, a case where the extension direction of each slit  31  formed by the electrode branches  13 A of the pixel electrode  13  is parallel to the Y-axis direction or crosses the Y-axis direction at an acute angle has been described. 
     Alternatively, the extension direction of each slit  31  formed by the electrode branches  13 A of the pixel electrode  13  may be parallel to the X-axis direction or may cross the X-axis direction at an acute angle. 
       FIG.  19    shows an example of such a pixel structure.  FIG.  19    shows a pixel structure example when the pixel electrode  13  and the counter electrode  15  are disposed in different layers on the glass substrate  5  ( FIG.  1   ). Of course, the same pixel structure as the sixth pixel structure example may also be considered. 
     Description will be made again with reference to  FIG.  19   . In  FIG.  19   , the electrode branches  13 A of the pixel electrode  13  are formed in parallel to the scanning line  23 . Both ends of the electrode branches  13 A are connected by connection portions  13 B. For this reason, a slit  31  formed between the electrode branches  13 A extends in the X direction. 
     In this pixel structure example, the alignment regulation force is likely to be weakened at the boundary between the contact portion  13 C and the electrode branch  13 A directly extending from the contact portion  13 C. 
     However, the partial connection branch  81  is formed so as to transverse the electrode branches  13 A, so, as in the above-described pixel structure examples, a reverse twist line due to the application of external pressure in the relevant region can be effectively prevented from growing. 
     (I) Other Examples 
     (I-1) Substrate Material 
     In the above description of the examples, the substrate is a glass substrate, but a plastic substrate or other substrates may be used. 
     (I-2) Alignment Direction  1  of Alignment Film 
     Of the above-described examples, in the case of the pixel structure example 1 ( FIG.  8   ), it is assumed that the alignment direction of the liquid crystal layer  7  and the extension direction of the slit  31  cross each other at an acute angle of about 3°. 
     Of course, when the cross angle α is equal to or larger than 7°, similarly to the pixel structure example 2 ( FIG.  10   ), the generated reverse twist line can be eliminated when the liquid crystal panel is left uncontrolled. 
     (I-3) Alignment Direction  1  of Alignment Film 
     Of the above-described examples, in the case of the pixel structure example 2 ( FIG.  10   ), the pixel structure example 3 ( FIG.  14   ), and the pixel structure example 4 ( FIG.  15   ), an example where the cross angle α formed between the alignment direction of the liquid crystal layer  7  and the extension direction of the slit  31  is equal to or larger than 7° has been described. 
     Alternatively, the cross angle α may be smaller than 7°. In this case, display irregularity remains, but as described with reference to  FIG.  9   , a reverse twist line can be effectively prevented from growing at the central portion of the pixel region, so display quality can be improved. 
     (I-4) Product Examples 
     In the above description, various pixel structures capable of generating a transverse electric field have been described. Hereinafter, description will be provided for electronic apparatuses in which a liquid crystal panel having the pixel structure according to the examples (with no driving circuit mounted therein) or a liquid crystal panel module (with a driving circuit mounted therein) is mounted. 
       FIG.  20    shows a conceptual example of the configuration of an electronic apparatus  111 . The electronic apparatus  111  includes a liquid crystal panel  113  having the above-described pixel structure, a system control unit  115 , and an operation input unit  117 . The nature of processing performed by the system control unit  115  varies depending on the product type of the electronic apparatus  111 . 
     The configuration of the operation input unit  117  varies depending on the product type. A GUI (Graphic User Interface), switches, buttons, a pointing device, and other operators may be used as the operation input unit  117 . 
     It should be noted that the electronic apparatus  111  is not limited to an apparatus designed for use in a specific field insofar as it can display an image or video generated inside or input from the outside. 
       FIG.  21    shows an appearance example of a television receiver as an electronic apparatus. A television receiver  121  has a display screen  127  on the front surface of its housing. The display screen  127  includes a front panel  123 , a filter glass  125 , and the like. The display screen  127  corresponds to the liquid crystal panel according to the embodiment. 
     The electronic apparatus  111  may be, for example, a digital camera.  FIGS.  22 A and  22 B  show an appearance example of a digital camera  131 .  FIG.  22 A  shows an appearance example as viewed from the front (from the subject), and  FIG.  22 B  shows an appearance example when viewed from the rear (from the photographer). 
     The digital camera  131  includes a protective cover  133 , an imaging lens section  135 , a display screen  137 , a control switch  139 , and a shutter button  141 . Of these, the display screen  137  corresponds to the liquid crystal panel according to the embodiment. 
     The electronic apparatus  111  may be, for example, a video camcorder.  FIG.  23    shows an appearance example of a video camcorder  151 . 
     The video camcorder  151  includes an imaging lens  155  provided to the front of a main body  153  so as to capture the image of the subject, a photographing start/stop switch  157 , and a display screen  159 . Of these, the display screen  159  corresponds to the liquid crystal panel according to the embodiment. 
     The electronic apparatus  111  may be, for example, a personal digital assistant.  FIGS.  24 A and  24 B  show an appearance example of a mobile phone  161  as a personal digital assistant. The mobile phone  161  shown in  FIGS.  24 A and  24 B  is a folder type mobile phone.  FIG.  24 A  shows an appearance example of the mobile phone in an unfolded state, and  FIG.  24 B  shows an appearance example of the mobile phone in a folded state. 
     The mobile phone  161  includes an upper housing  163 , a lower housing  165 , a connection portion (in this example, a hinge)  167 , a display screen  169 , an auxiliary display screen  171 , a picture light  173 , and an imaging lens  175 . Of these, the display screen  169  and the auxiliary display screen  171  correspond to the liquid crystal panel according to the embodiment. 
     The electronic apparatus  111  may be, for example, a computer.  FIG.  25    shows an appearance example of a notebook computer  181 . 
     The notebook computer  181  includes a lower housing  183 , an upper housing  185 , a keyboard  187 , and a display screen  189 . Of these, the display screen  189  corresponds to the liquid crystal panel according to the embodiment. 
     In addition to the above-described electronic apparatuses, the electronic apparatus  111  may be, for example, a projector, an audio player, a game machine, an electronic book, an electronic dictionary, or the like. 
     It should be understood that various changes and modifications to the presently preferred embodiments described herein will be apparent to those skilled in the art. Such changes and modifications can be made without departing from the spirit and scope and without diminishing its intended advantages. It is therefore intended that such changes and modifications be covered by the appended claims.