JP5286974B2 - Liquid crystal display element - Google Patents

Description

This invention relates to a liquid crystal display device having a liquid crystal layer having a horizontal alignment film and positive dielectric anisotropy.

  A liquid crystal display element having a liquid crystal layer having a positive dielectric anisotropy forms a plurality of pixels on the mutually facing inner surfaces of a pair of substrates arranged opposite to each other with a predetermined gap, by areas facing each other. And a horizontal alignment film formed so as to cover the electrodes and rubbed in a predetermined direction, and the liquid crystal layer is sealed in the gap between the pair of substrates. Yes.

This type of liquid crystal display element is desired to have a wide viewing angle. Therefore, conventionally, for each of a plurality of pixels, liquid crystal molecules are aligned at a first pretilt angle by forming a convex portion having a triangular cross section on the alignment film of one substrate and rubbing the alignment film. Forming a first liquid crystal region and a second liquid crystal region in which liquid crystal molecules are aligned at a second pretilt angle whose pretilt angle is opposite to the first pretilt angle, thereby improving viewing angle characteristics. (See Patent Document 1).
JP-A-7-333612

  However, the above-mentioned conventional liquid crystal display element is difficult to manufacture because convex portions having a triangular cross section must be formed by taper etching on alignment films provided on the inner surfaces of a pair of substrates.

  An object of the present invention is to provide a liquid crystal display element that has a wide viewing angle and can be easily manufactured.

In order to solve the above problems, an embodiment of the liquid crystal display element of the present invention includes a pair of substrates each including a first substrate and a second substrate that are opposed to each other with a predetermined gap therebetween, and the pair of substrates. A plurality of pixel electrodes arranged in a matrix in the row direction and the column direction on the inner surface of the first substrate among the mutually opposing inner surfaces, and the plurality of pixels on the inner surface of the first substrate An insulating film is provided between each of the plurality of thin film transistors provided corresponding to each of the electrodes and connected to each of the corresponding pixel electrodes, and the plurality of pixel electrodes closer to the first substrate than the plurality of pixel electrodes. It is provided in an intervening manner and overlaps with the periphery of each of the plurality of pixel electrodes in plan view, and the outer periphery is formed in a shape projecting around the pixel electrode, and the periphery and the periphery of the plurality of pixel electrodes Said part between An auxiliary electrode for generating a lateral electric field along the inner surface of the substrate, the inner surface of the second substrate, a counter electrode provided to face said plurality of pixel electrodes, wherein the plurality of the counter electrode A plurality of dielectric layers provided in correspondence with predetermined portions of the plurality of pixel electrodes on a surface facing the pixel electrodes, and a plurality of pixel electrodes and the inner surfaces of the pair of substrates, respectively. A liquid crystal having a positive dielectric anisotropy enclosed in a gap between the pair of substrates, and a horizontal alignment film which is provided so as to cover the counter electrode and the dielectric layer, each of which is rubbed in a predetermined direction. Each of the plurality of pixel electrodes is divided into regions such that the plurality of electrode portions are arranged in one column along the column direction by at least one slit provided along the row direction, The plurality of electrodes Are connected to each other in at least one connecting portion, and the auxiliary electrode is wider in the row direction and the column direction than the entire area of the slit, and overlaps with the entire area of the slit in plan view, on the counter electrode The dielectric layer is provided so as to correspond to each of the plurality of electrode portions of the pixel electrode.

  Since the liquid crystal display element of the present invention has the above-described configuration, it has a wide viewing angle and can be easily manufactured.

(First embodiment)
1 to 10 show a first embodiment of the present invention. FIG. 1 is a plan view of a part of a first substrate of a liquid crystal display element, and FIGS. 2 and 3 are II-II lines in FIG. It is an expanded sectional view of the liquid crystal display element along line III-III.

This liquid crystal display element is an active matrix liquid crystal display element in which a thin film transistor (hereinafter referred to as TFT) is an active element. As shown in FIG. 1 to FIG. A second pair of transparent substrates 1 and 2 and a first substrate of the inner surfaces facing each other of the pair of substrates 1 and 2, for example, a substrate on the opposite side to the observation side (upper side in FIGS. 2 and 3) A plurality of transparent pixel electrodes 3 arranged in a matrix in the row direction and the column direction on the inner surface of 1 (hereinafter referred to as a rear substrate), and the plurality of pixel electrodes 3 on the inner surface of the rear substrate 1 A plurality of TFTs 4 provided in the vicinity thereof and connected to the corresponding pixel electrodes 3 respectively, and provided on the inner surface of the rear substrate 1, respectively, supply gate signals and data signals to the plurality of TFTs 4. A plurality of scanning lines 10 and signal lines 11, a second substrate, i.e. the viewing side of the substrate (hereinafter, front substrate hereinafter) to the inner surface of 2, one film provided so as to face said plurality of pixel electrodes 3 A transparent electrode 15 having a shape, a liquid crystal layer 20 having positive dielectric anisotropy sealed in a gap between the pair of substrates 1 and 2, an outer surface of the rear substrate 1, and an outer surface of the front substrate 2 Are provided with a rear polarizing plate 21 and a front polarizing plate 22 , respectively.

  The TFT 4 includes a gate electrode 5 formed on the rear substrate 1, a transparent gate insulating film 6 that covers the gate electrode 5 and is formed over the entire array region of the pixel electrode 3, and the gate insulating film 6. An i-type semiconductor film 7 is formed on the gate electrode 5 so as to face the gate electrode 5, and an n-type semiconductor film (not shown) is formed on one side and the other side of the i-type semiconductor film 7. It consists of a drain electrode 8 and a source electrode 9.

  The plurality of scanning lines 10 are provided on one side of each row corresponding to each pixel electrode row including the plurality of pixel electrodes 3 arranged in the row direction on the rear substrate 1. The plurality of signal lines 11 are connected to the gate electrodes 5 of the plurality of TFTs 4. The plurality of signal lines 11 correspond to the respective pixel electrode columns formed of the plurality of pixel electrodes 3 arranged in the column direction on the gate insulating film 6. Provided on one side of these columns and connected to the drain electrodes 8 of the plurality of TFTs 4 in each column.

  The plurality of pixel electrodes 3 are formed on the gate insulating film 6, and the source electrodes 9 of the TFTs 4 corresponding to the pixel electrodes 3 are connected to the pixel electrodes 3, respectively. In this embodiment, each of the plurality of pixel electrodes 3 has two directions orthogonal to each other, that is, a horizontal width in a direction parallel to the horizontal direction of the screen and a vertical width in a direction parallel to the vertical direction of the screen. It is formed in a square shape of ˜300 μm.

  Further, the liquid crystal display element is provided on the rear substrate 1 side of the plurality of pixel electrodes 3 with the gate insulating film 6 interposed between the plurality of pixel electrodes 3 and the plurality of pixel electrodes. 3 is formed in a shape corresponding to substantially the entire circumference of each of the peripheral portions, and the outer peripheral portion extends around the pixel electrode 3, and a compensation capacitor is formed between each of the plurality of pixel electrodes 3, and the A transparent auxiliary electrode 12 that generates a horizontal electric field along the surface of the substrate 1 is provided between the outer peripheral portion and the peripheral portions of the plurality of pixel electrodes 3. In FIG. 1, parallel diagonal lines are given to portions corresponding to the auxiliary electrodes 12.

  The auxiliary electrode 12 is formed in a frame shape on the rear substrate 1 so as to correspond to substantially the entire circumference of the peripheral portion of each of the plurality of pixel electrodes 3 other than the connection portion of the TFT 4. The plurality of scanning lines 10 and signal lines 11 are provided at positions outside the auxiliary electrode 12 with respect to the pixel electrode 3.

  Each of the four sides of the auxiliary electrode 12 is formed to have a width of 4 to 6 μm, and a region having a width of 2 to 3 μm inside the center of these sides is interposed through the gate insulating film 6. A region having a width of 2 to 3 μm opposite to the peripheral edge of the pixel electrode 3 and extending outside the center extends around the pixel electrode 3.

  The auxiliary electrodes 12 respectively corresponding to the peripheral edge portions of the plurality of pixel electrodes 3 are formed continuously in each row, and are connected in common at one end or both ends of each row (not shown). ) A voltage having the same potential as that of the counter electrode 15 is applied to the auxiliary electrode 12, and a lateral electric field is generated between the auxiliary electrode 12 and the peripheral edge of the pixel electrode 3.

  Further, an overcoat insulating film 13 is provided on the inner surface of the rear substrate 1 so as to cover the plurality of TFTs 4 and the plurality of signal lines 11, and the plurality of pixel electrodes 3 are disposed in the entire arrangement region of the pixel electrodes 3. A horizontal alignment film 14 is provided.

  On the other hand, a light shielding film (black mask) 16 formed on the inner surface of the front substrate 2 so as to correspond to a region between the plurality of pixel electrodes 3 arranged in a matrix, and the plurality of pixel electrodes 3. Red, green, and blue color filters 17R, 17G, and 17B formed in correspondence with each other are provided, and the counter electrode 15 is provided on the rear substrate 1 of the color filters 17R, 17G, and 17B. It is formed on the opposite surface.

  Furthermore, the liquid crystal display element includes a plurality of dielectric bodies provided on the surface of the counter electrode 15 facing the plurality of pixel electrodes 3 so as to correspond to predetermined portions of the plurality of pixel electrodes 3, respectively. Layer 18 is provided.

  The dielectric layer 18 has a diameter of 10 to 30 μm and a thickness of 1 to 1 corresponding to the center of the plurality of pixel electrodes 3 formed in a square shape having a horizontal width and a vertical width of 100 to 300 μm, respectively. It is formed in a 2 μm circular film shape.

  Further, a horizontal alignment film 19 is provided on the inner surface of the front substrate 2 so as to cover the counter electrode 15 and the plurality of dielectric layers 18 over the entire region corresponding to the arrangement region of the plurality of pixel electrodes 3. Yes.

  The pair of substrates 1 and 2 are joined via a frame-shaped sealing material (not shown) surrounding the array region of the plurality of pixel electrodes 3. A liquid crystal layer 20 made of nematic liquid crystal having positive dielectric anisotropy is sealed in a region surrounded by the sealing material.

  The rear substrate 1 is formed with a driver mounting portion (not shown) extending outward from the front substrate 2 on one or two side edges orthogonal to each other, and the plurality of scans. The line 10 and the signal line 11 are respectively connected to a plurality of gate signal output terminals and data signal output terminals of a driver element mounted on the driver mounting portion, and a common connection portion of the plurality of auxiliary electrodes 12 in each row is Connected to the counter electrode signal output terminal of the driver element, and the counter electrode 15 is connected to the counter electrode signal output terminal of the driver element through a cross connection portion provided at the substrate joint portion by the frame-shaped sealing material Has been.

  The liquid crystal display element of this embodiment is a TN (twisted nematic) type element, and the horizontal alignment films 14 and 19 provided on the inner surfaces of the pair of substrates 1 and 2 are substantially perpendicular to each other. Has been rubbed. Each of the alignment films 14 and 19 has an alignment characteristic that aligns the liquid crystal molecules 20a with a very small pretilt angle of about 0.5 °.

  In FIG. 1, chain line arrows 14a and 19a indicate the rubbing directions of the alignment films 14 and 19. In this embodiment, the alignment film 14 of the rear substrate 1 is viewed from the observation side with respect to the horizontal direction of the screen. A rubbing process is performed from the diagonally upper left direction of the screen toward the diagonally lower right direction in a direction that intersects the clockwise direction at an angle of substantially 45 °, and the alignment film 19 of the front substrate 2 is aligned in the horizontal direction of the screen. On the other hand, rubbing is performed from the diagonally lower left direction of the screen toward the diagonally upper right direction in a direction that intersects the counterclockwise direction substantially at an angle of 45 ° as viewed from the viewing side.

The liquid crystal molecules 20a of the liquid crystal layer 20 are oriented in the vicinity of the pair of substrates 1 and 2 with their molecular major axes directed to the rubbing directions 14a and 19a of the alignment films 14 and 19, and the rubbing directions 14a and 19a. In a state in which the pair is pretilted at an angle of 2 ° or less from the upstream side (rubbing start end side) to the downstream side (rubbing end end side) in a direction away from the film surface of the alignment films 14 and 19. Between the substrates 1 and 2, the twist orientation is substantially 90 ° in the twist direction indicated by the broken line arrow in FIG.

  Further, the rear polarizing plate 21 is disposed so that its absorption axis (not shown) is substantially parallel to or substantially orthogonal to the rubbing direction 14a of the alignment film 14 of the rear substrate 1, The front polarizing plate 22 is disposed with its absorption axis (not shown) substantially orthogonal to the absorption axis of the rear polarizing plate 21 or substantially parallel.

  Since the liquid crystal display element has the above-described configuration, a region where the plurality of pixel electrodes 3 and the counter electrode 15 face each other by applying an electric field between the pixel electrode 3 and the counter electrode 15. For each of the plurality of pixels 30, two regions having different tilt directions of the liquid crystal molecules 20 a can be formed to widen the viewing angle of display.

  That is, the liquid crystal display element is a TN type element, and the liquid crystal molecules 20a of the liquid crystal layer 20 are formed between the pair of substrates 1 and 2 when no electric field is applied between the pixel electrode 3 and the counter electrode 15. Twist alignment is performed with respect to the film surfaces of the alignment films 14 and 19 on the inner surface in a pretilt direction from the upstream side to the downstream side in the rubbing directions 14a and 19a of the alignment films 14 and 19, By applying an electric field between 15, the substrate is raised from the twist alignment state with respect to the surfaces of the substrates 1 and 2.

  FIG. 4 is a schematic diagram showing the rising orientation of the liquid crystal molecules 20a due to the application of an electric field in the liquid crystal display element. In the figure, a broken line arrow E1 indicates an electric field applied between the pixel electrode 3 and the counter electrode 15. ing.

  In addition, since the liquid crystal display element includes the auxiliary electrode 12 connected to the same potential as the counter electrode 15, when the electric field E 1 is applied between the pixel electrode 3 and the counter electrode 15, 4, the electric field E <b> 1 applied between the pixel electrode 3 and the counter electrode 15 between the outer peripheral portion of the auxiliary electrode 12 and the peripheral portion of the pixel electrode 3 has substantially the same strength. A horizontal electric field (a horizontal electric field along the surface of the rear substrate 1) E2 is generated, and the liquid crystal molecules 20a near the periphery of the pixel electrode 3 are tilted along the direction of the horizontal electric field E2.

  The lateral electric field E2 is an electric field in a direction from each edge of the pixel electrode 3 toward a corresponding side of the auxiliary electrode 12, and is thus generated in a region corresponding to each edge of the pixel electrode 3. Since the horizontal electric field E2 is an electric field opposite to the direction of the horizontal electric field E2 generated in the region corresponding to the edge opposite to the edge, the tilt of the liquid crystal molecules 20a by the horizontal electric field E2 is reduced. The inclinations are opposite to each other in a region corresponding to one edge of the pixel electrode 3 in the left-right direction and a region corresponding to the other edge, and the vertical direction of the pixel electrode 3 (up and down of the screen). The region corresponding to one edge of the direction) and the region corresponding to the other edge are opposite to each other.

  In the liquid crystal display element, the alignment film 14 on the inner surface of the rear substrate 1 is crossed at a substantially 45 ° angle in the clockwise direction when viewed from the observation side with respect to the horizontal direction of the screen. Since the rubbing process is performed from the diagonally upper left direction to the diagonally lower right direction of the screen, the inclination in which the liquid crystal molecules 20a are tilted by the lateral electric field E2 in the regions corresponding to the right and lower edges of the pixel electrode 3 Is the same inclination (hereinafter referred to as forward inclination) as the pretilt inclination obtained by the rubbing direction 14a of the alignment film 14 on the inner surface of the rear substrate 1, and corresponds to the left and upper edges of the pixel electrode 3. The tilt at which the liquid crystal molecules 20a are tilted by the lateral electric field E2 is a tilt opposite to the pretilt direction obtained by the rubbing direction 14a of the alignment film 14 (hereinafter referred to as reverse tilt).

  Further, the liquid crystal display element is formed on the surface of the counter electrode 15 provided on the inner surface of the front substrate 2 so as to be opposed to the plurality of pixel electrodes 3 and corresponding to predetermined portions of the plurality of pixel electrodes 3. Since a plurality of dielectric layers 18 are provided, the electric field E1 between the pixel electrode 3 and the counter electrode 15 is caused by the voltage drop in the dielectric layer 18 due to the electric field in the region corresponding to the dielectric layer 18. 4, the pixel electrode 3 is distorted so as to spread radially from the portion corresponding to the center of the dielectric layer 18 toward the periphery of the dielectric layer 18, and the distorted electric field causes the dielectric The liquid crystal molecules 20 a in the region corresponding to the body layer 18 are tilted outward from the portion corresponding to the dielectric layer 18.

  That is, the liquid crystal molecules 20a in the peripheral region of the dielectric layer 18 are in the rubbing direction 14a on the downstream side of the rubbing direction 14a of the alignment film 14 on the inner surface of the rear substrate 1 with the dielectric layer 18 as a boundary. Tilt with a forward inclination corresponding to the above-mentioned direction, and on the upstream side of the rubbing direction 14a, it tilts with a reverse inclination relative to the rubbing direction 14a.

  Then, the liquid crystal molecules 20a in the other regions in the pixel 30 are aligned under the influence of the intermolecular force between the liquid crystal molecules 20a in the peripheral portion of the pixel 30 and the peripheral region of the dielectric layer 18. When an electric field E1 is applied between the pixel electrode 3 and the counter electrode 15, the liquid crystal molecules 20a in the pixel 30 are substantially orthogonal to the rubbing direction 14a of the alignment film 14 on the inner surface of the rear substrate 1, In addition, it is tilted at the forward inclination in the region on the downstream side (the right side and the lower side of the pixel 30) of the rubbing direction 14a with respect to the line passing through the position of the dielectric layer 18, and the upstream side of the rubbing direction 14a ( In the region on the left side and the upper side of the pixel 30, tilting is performed with the reverse inclination.

  FIG. 5 is a perspective view showing the rising alignment of the liquid crystal molecules 20a due to the application of an electric field in the liquid crystal display element, and FIG. 5 (a) shows the rising alignment of the region where the liquid crystal molecules 20a are tilted in the forward inclination. b) shows the rising alignment state of the region where the liquid crystal molecules 20a are tilted in the reverse tilt.

  Thus, according to the liquid crystal display element, the liquid crystal molecules 20a are tilted at the forward inclination by applying the electric field E1 between the pixel electrode 3 and the counter electrode 15 for each of the plurality of pixels 30. And a region where the liquid crystal molecules 20a are tilted with the reverse tilt (reverse tilt region), and a field of view of each of the two regions having different tilt directions. A wide viewing angle with a synergistic angular characteristic can be obtained.

In the liquid crystal display element, each of the plurality of pixel electrodes 3 is formed in a substantially square shape, and the dielectric layer 18 on the counter electrode 15 is formed at the center of the plurality of pixel electrodes 3, that is, Of the peripheral edge of the pixel electrode 3, the upstream side of the rubbing direction 14a of the alignment film 14 on the inner surface of the rear substrate 1, that is, the left and upper edges, and the downstream side of the rubbing direction 14a, that is, the right side and the lower side. for being provided respectively in correspondence to the intermediate vicinity of the portion of the edge, and the forward tilt region, substantially the same west the area between the opposite tilt area, the viewing angle characteristics of each of these two areas balanced A well-synthesized wide viewing angle can be obtained.

  6 shows that the pixel electrode 3 is formed in a substantially square shape, the dielectric layer 18 is provided so as to correspond to the center of the pixel electrode 3, and the alignment film 14 on the inner surface of the rear substrate 1 is provided. The forward tilt region and the reverse tilt region of the liquid crystal molecules 20a in one pixel 30 when the rubbing process is performed in a direction 14a having a substantially 45 ° angle in the clockwise direction when viewed from the observation side with respect to the left-right direction of the screen In this example, the vicinity of a diagonal line in the direction substantially orthogonal to the rubbing direction 14a of the alignment film 14 of the pixel 30 is defined as a boundary 31, and the downstream side of the rubbing direction 14a of the alignment film 14, that is, the pixel 30 The liquid crystal molecules 20a in the triangular region 30a on the lower right side are tilted forward, and the liquid crystal molecules 2 in the triangular region 30b on the upper side of the rubbing direction 14a of the alignment film 14, that is, the upper left side of the pixel 30 in the triangular region 30b. a to reverse tilt.

  FIGS. 7 to 10 are viewing angle-luminance characteristic diagrams of the liquid crystal display element of the comparative example in which the liquid crystal molecules are tilted in the forward direction in the entire pixel and the liquid crystal display element of the above-described embodiment, and FIG. FIG. 8 shows the characteristics of the time direction (up and down direction of the screen), FIG. 8 shows the characteristics of the 9 o'clock to 3 o'clock direction (left and right direction of the screen), and FIG. 10 shows the characteristics in the 4:30 to 10:30 direction (45 ° clockwise with respect to the horizontal direction of the screen). These viewing angle-luminance characteristics are viewing angle-luminance characteristics when an electric field having a gradation value of 0 to 8 is applied between the electrodes of a plurality of pixels. In each figure, L1 represents an electric field having a gradation value of 0. Characteristics when applied, L2 is a characteristic when an electric field with a gradation value of 2 is applied, L4 is a characteristic when an electric field with a gradation value of 4 is applied, and L6 is an electric field with a gradation value of 6 Characteristic L8 is a characteristic when an electric field having a gradation value of 8 is applied.

  As shown in FIG. 7A, FIG. 8A, FIG. 9A, and FIG. 10A, the liquid crystal display element of the comparative example in which the liquid crystal molecules are tilted in the whole pixel is in the 9 o'clock to 3 o'clock direction. The viewing angle-luminance characteristic is substantially symmetrical with respect to the normal direction of the screen (the viewing angle direction of 0 °), and the viewing angle range in which a display with sufficient contrast can be observed is a sufficiently wide characteristic. The viewing angle-luminance characteristics in the 12 o'clock direction, 7: 30-1: 30, and 4: 30-10: 30 are asymmetrical, and the viewing angle range in either the left or right direction is narrow.

  In contrast to this comparative example, the liquid crystal display element of the above-described example has a 6 o'clock to 12 o'clock direction as shown in FIGS. 7B, 8B, 9B, and 10B. The viewing angle-luminance characteristics in the 9 o'clock-3 o'clock direction, 7:30-1 o'clock direction, and 4:30-10 o'clock direction are all substantially symmetrical and sufficient with respect to the normal direction of the screen. The viewing angle range in which the contrast display can be observed is sufficiently wide.

  The liquid crystal display element includes a gate insulating film interposed between the plurality of pixel electrodes 3 to form a compensation capacitor with each of the plurality of pixel electrodes 3, and the plurality of pixel electrodes 3. An auxiliary electrode 12 that generates a lateral electric field E2 is provided between the peripheral edge of the counter electrode 15 and a predetermined portion of the plurality of pixel electrodes 3 on the surface of the counter electrode 15 facing the pixel electrodes 3 respectively. By providing the dielectric layer 18, a forward tilt region in which the liquid crystal molecules 20 a tilt forward when the electric field is applied between the pixel electrode 3 and the counter electrode 15, and the liquid crystal Since the reverse tilt region in which the molecules 20a are reverse tilted is formed, it can be manufactured more easily than the conventional liquid crystal display element described in Patent Document 1.

  In the above embodiment, each of the plurality of pixel electrodes 3 is formed in a substantially square shape. However, the plurality of pixel electrodes 3 may be formed in a rectangular shape. 15 on the edge of the alignment film 14 on the inner surface of the rear substrate 1 on the upstream side in the rubbing direction 14a and the edge on the downstream side in the rubbing direction 14a. By providing it corresponding to a portion in the vicinity of the middle of the part, it is possible to obtain a wide viewing angle in which the viewing angle characteristics of the forward tilt region and the viewing angle characteristics of the reverse tilt region are synergistically balanced.

(Second embodiment)
FIG. 11 is a plan view of a part of the first substrate of the liquid crystal display device according to the second embodiment of the present invention. In this embodiment, components corresponding to those of the first embodiment described above are denoted by the same reference numerals, and description of the same components is omitted.

  In the liquid crystal display element of this embodiment, on the inner surface of the rear substrate 1, one of two directions orthogonal to each other, for example, the vertical width in a direction parallel to the vertical direction of the screen is the horizontal direction of the screen. A plurality of substantially square-shaped, that is, three, three rectangular shapes, which are substantially integral multiples of the horizontal width, for example, substantially three times the rectangular shape, and are provided in parallel with the left-right direction of the screen. A plurality of pixel electrodes 40 formed in a shape divided into electrode portions 40a, 40b, and 40c are provided, and the TFT 4 is disposed between the plurality of pixel electrodes 40 on the rear substrate 1 side with respect to the plurality of pixel electrodes 40. The plurality of pixel electrodes are formed in a substantially “eye” shape corresponding to the peripheral portions of the plurality of electrode portions 40a, 40b, and 40c of the pixel electrode 40 with the gate insulating film 6 interposed therebetween. 40 with each A counter electrode 15 (see FIGS. 1 to 3) provided on the inner surface of the front substrate 2 is provided with an auxiliary electrode 42 that forms a compensation capacitor and generates a lateral electric field between the peripheral edges of the plurality of pixel electrodes 40. On the surface of the pixel electrode 40 facing the plurality of pixel electrodes 40, that is, the central portions of the plurality of electrode portions 40a, 40b, 40c of the pixel electrode 40, that is, the peripheral edges of the plurality of electrode portions 40a, 40b, 40c, respectively. Near the middle between the upstream (left and upper) edge of the alignment film 14 on the inner surface of the rear substrate 1 in the rubbing direction and the downstream (right and lower) edge of the rubbing direction 14a. A dielectric layer 18 is provided corresponding to each of the portions.

  In this embodiment, the pixel electrode 40 is formed by forming the three electrode portions 40a, 40b, and 40c into a square shape having a size of about 100 μm × 100 μm. The slit 40 divided into 40a, 40b, and 40c is formed to have a width of about 3 μm from a portion about 3 μm inside one side edge of the pixel electrode 40 to the other side edge of the pixel electrode 40.

  Further, the four side portions of the auxiliary electrode 42 corresponding to the outer peripheral edge of the pixel electrode 40 are each formed to have a width of 4 to 6 μm, and the portions corresponding to the two slits 40 are respectively set to have a width of 6 to 10 μm. The inner edges of the four sides and the side edges of the portion corresponding to the slit 40 are respectively opposed to the peripheral edges of the electrode portions 40a, 40b, and 40c with a width of 2 to 3 μm. The outer edge portions of the four side portions and portions corresponding to the inside of the slit 40 protrude around the electrode portions 40a, 40b, and 40c, respectively.

  Furthermore, the dielectric layers 18 respectively corresponding to the central portions of the electrode portions 40a, 40b, and 40c of the pixel electrode 40 are formed in a circular film shape having a diameter of 10 to 30 μm and a thickness of 1 to 2 μm. .

Since the liquid crystal display element of the second embodiment is configured as described above, the application of an electric field between the pixel electrode 40 and the counter electrode 15 causes the pixel electrode 40 and the counter electrode 15 to interact with each other. For each square area corresponding to each of the three electrode portions 40a, 40b, 40c of the pixel electrode 40 of the pixel composed of the opposed areas, the order corresponding to the rubbing direction 14a of the alignment film 14 on the inner surface of the rear substrate 1 is obtained. regions in which the liquid crystal molecules are tilted at a tilt (the forward tilt region), a region where the liquid crystal molecules are tilted in the reverse tilt (reverse tilt domain) to the rubbing direction 14a of the alignment layer 14, can be formed.

  That is, FIG. 12 shows that the alignment film 14 on the inner surface of the rear substrate 1 of the liquid crystal display element of the second embodiment is substantially 45 ° clockwise when viewed from the observation side with respect to the horizontal direction of the screen. A forward tilt region and a reverse tilt region of liquid crystal molecules in one pixel 50 when the rubbing process is performed in the angle direction 14a are shown. In this example, three electrode portions 40a and 40b of the pixel electrode 40 of the pixel 50 are shown. , 40 c for each of the square regions 51, 52, 53 corresponding to the diagonal lines 54, 55, 56 in the direction substantially perpendicular to the rubbing direction 14 a of the alignment film 14, as the rubbing direction of the alignment film 14. 14a, that is, the liquid crystal molecules in the triangular regions 51a, 52a, 53a obliquely lower right of the square regions 51, 52, 53 are forward tilted, and the rubbing direction of the alignment layer 14 Upstream of 4a, i.e. upper left triangular region 51b of the respective square regions 51, 52, 53, 52 b, the liquid crystal molecules 53b reverse tilt.

  Therefore, according to the liquid crystal display element of the second embodiment, the viewing angle can be widened and more easily manufactured compared to the conventional liquid crystal display element described in Patent Document 1.

  In the second embodiment, each of the electrode portions 40a, 40b, and 40c of the pixel electrode 40 is formed in a substantially square shape. However, the electrode portions 40a, 40b, and 40c are in a rectangular shape. In this case, the dielectric layer 18 on the counter electrode 15 may be rubbed on the alignment film 14 on the inner surface of the rear substrate 1 in the peripheral portions of the electrode portions 40a, 40b, and 40c. Viewing angle characteristics of the forward tilt region in which the liquid crystal molecules are tilted at a forward tilt by being provided corresponding to a portion near the middle between the upstream edge of the direction 14a and the downstream edge of the rubbing direction 14a. It is possible to obtain a wide viewing angle in which the viewing angle characteristics of the reverse tilt region where the liquid crystal molecules tilt with reverse tilt are well balanced.

  In the second embodiment, the pixel electrode 40 is formed in a shape divided into three electrode portions 40a, 40b, and 40c. However, the pixel electrode 40 has two or more electrode portions. You may form in the shape divided into.

1 is a plan view of a part of a first substrate of a liquid crystal display device showing a first embodiment of the present invention; The expanded sectional view of the said liquid crystal display element which follows the II-II line | wire of FIG. The expanded sectional view of the said liquid crystal display element which follows the III-III line | wire of FIG. FIG. 3 is a schematic diagram showing rising alignment of liquid crystal molecules by applying an electric field in the liquid crystal display element. FIG. 3 is a perspective view showing rising alignment of liquid crystal molecules by applying an electric field in the liquid crystal display element. FIG. 3 is a diagram showing a forward tilt region and a reverse tilt region of liquid crystal molecules in one pixel of the liquid crystal display element. FIG. 6 is a viewing angle-luminance characteristic diagram in the 6 o'clock to 12 o'clock direction of the liquid crystal display element of the comparative example in which the liquid crystal molecules are tilted in the whole pixel and the liquid crystal display element of the first embodiment. FIG. 5 is a view angle-luminance characteristic diagram in the 9 o'clock to 3 o'clock direction of the liquid crystal display element of the comparative example and the liquid crystal display element of the first example. FIG. 7 is a view angle-luminance characteristic diagram in the 7: 30-1: 30 direction of the liquid crystal display element of the comparative example and the liquid crystal display element of the first example. FIG. 6 is a view angle-luminance characteristic diagram in the 4:30 to 10:30 direction of the liquid crystal display element of the comparative example and the liquid crystal display element of the first example. The top view of a part of 1st board | substrate of the liquid crystal display element which shows 2nd Example of this invention. The figure which shows the forward tilt area | region and reverse tilt area | region of the liquid crystal molecule in one pixel of the liquid crystal display element of a 2nd Example.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1, 2 ... Substrate, 3, 40 ... Pixel electrode, 40a, 40b, 40c ... Electrode part, 41 ... Slit, 4 ... TFT, 10 ... Scanning line, 11 ... Signal line, 12, 42 ... Auxiliary electrode, 14, 19 Alignment film, 14a, 19a ... rubbing direction, 15 ... counter electrode, 16 ... light shielding film, 17R, 17G, 17B ... color filter, 18 ... dielectric layer, 20 ... liquid crystal layer, 20a ... liquid crystal molecule, 21, 22 ... Polarizing plate, 30, 50 ... pixel, 51, 52, 53 ... square region, E1, E2 ... electric field, 30a, 51a, 52a , 53a ... forward tilt region, 30b, 51b, 52b , 53b ... reverse tilt region.

Claims (8)

A pair of substrates composed of a first substrate and a second substrate disposed opposite each other with a predetermined gap;
A plurality of pixel electrodes arranged in a matrix in the row direction and the column direction on the inner surface of the first substrate of the inner surfaces facing each other of the pair of substrates;
A plurality of thin film transistors provided on the inner surface of the first substrate so as to correspond to the plurality of pixel electrodes, respectively, and connected to the corresponding pixel electrodes;
An insulating film is provided between the plurality of pixel electrodes on the first substrate side of the plurality of pixel electrodes, and overlaps with a peripheral portion of each of the plurality of pixel electrodes in plan view. An auxiliary portion for forming a lateral electric field along the inner surface of the first substrate between the outer peripheral portion and the peripheral edge portions of the plurality of pixel electrodes. Electrodes,
A counter electrode provided on the inner surface of the second substrate so as to oppose the plurality of pixel electrodes;
A plurality of dielectric layers provided corresponding to predetermined portions of the plurality of pixel electrodes on a surface of the counter electrode facing the plurality of pixel electrodes;
A horizontal alignment film provided on each of the inner surfaces of the pair of substrates so as to cover the plurality of pixel electrodes, the counter electrode, and the dielectric layer, each of which is rubbed in a predetermined direction;
A liquid crystal layer having positive dielectric anisotropy enclosed in a gap between the pair of substrates;
With
Each of the plurality of pixel electrodes is divided into regions such that the plurality of electrode portions are arranged in one column along the column direction by at least one slit provided along the row direction, and the plurality of electrode portions are Connected to each other in at least one connection,
The auxiliary electrode is wider in the row direction and the column direction than the entire area of the slit, and overlaps the entire area of the slit in plan view,
The dielectric layer on the counter electrode is provided corresponding to each of the plurality of electrode portions of the pixel electrode.
The liquid crystal display element characterized by the above-mentioned.   Of the two edges of the pixel electrode along the column direction, the slit is provided from an edge far from the thin film transistor toward an edge near the thin film transistor. The liquid crystal display element according to claim 1.   The liquid crystal display element according to claim 1, wherein the plurality of electrode portions are separated by the slits other than the connection portions. Each of the plurality of pixel electrodes has a width in the column direction that is substantially an integer multiple of a width in the row direction.
The liquid crystal display element according to claim 1, wherein each of the plurality of electrode portions is formed in a substantially square shape.   The liquid crystal display element according to claim 1, wherein the dielectric layer on the counter electrode is formed in a circular shape.   The liquid crystal display element according to claim 5, wherein the dielectric layer on the counter electrode is formed in a circular film shape having a diameter of 10 to 30 μm and a thickness of 1 to 2 μm. The horizontal alignment film provided on each inner surface of the pair of substrates are rubbed in a direction substantially orthogonal to one another, the liquid crystal molecules of the liquid crystal layer, the twist of substantially 90 ° between the pair of substrates The liquid crystal display element according to claim 1, wherein the liquid crystal display element is twist-oriented at a corner.   7. The auxiliary electrode according to claim 1, wherein the auxiliary electrode is set to the same potential as the counter electrode, and a compensation capacitor is formed between the plurality of pixel electrodes via the insulating film. A liquid crystal display element according to 1.

Images