JP2006154564A - Liquid crystal display element - Google Patents

Abstract

There is provided a vertical alignment type active matrix liquid crystal display element capable of reducing the disorder of alignment of liquid crystal molecules in a region adjacent to a TFT of a pixel and displaying a good quality image without a feeling of roughness.
SOLUTION: The inner surface of one substrate 1 provided with a plurality of pixel electrodes 3, TFTs 4, gate wirings 11 and data wirings 12 is respectively associated with at least a portion adjacent to the TFTs 4 around the plurality of pixel electrodes 3. An auxiliary electrode 14 for forming an electric field having a predetermined value is provided between the counter electrode provided on the inner surface of the other substrate.
[Selection] Figure 1

Description

  The present invention relates to a vertical alignment type active matrix liquid crystal display element using a thin film transistor (hereinafter referred to as TFT) as an active element.

A vertical alignment type active matrix liquid crystal display device is provided on the inner surface of one of a pair of substrates opposed to each other with a predetermined gap and the inner surfaces of the pair of substrates facing each other. A plurality of pixel electrodes arranged in a matrix in the direction and the column direction, and a plurality of pixel electrodes provided in the vicinity of the inner surface of the one substrate so as to correspond to the plurality of pixel electrodes and connected to the corresponding pixel electrodes, respectively. TFTs are provided on the inner surface of the one substrate along one side of each pixel electrode row and one side of each pixel electrode column, and supply gate signals and data signals to the TFTs in that row and column. A plurality of gate wirings and data wirings, provided on the inner surface of the other substrate, facing the plurality of pixel electrodes, and provided on the inner surfaces of the pair of substrates so as to cover the electrodes, respectively. A vertical alignment film consists of a liquid crystal layer having negative dielectric anisotropy is sealed in a gap between the pair of substrates (see Patent Document 1).
Japanese Patent No. 2565639

  In a vertical alignment type liquid crystal display element, liquid crystal molecules are tilted from a vertical alignment state by applying a write voltage between the electrodes for each of a plurality of pixels composed of regions where a plurality of pixel electrodes and a counter electrode face each other. To display the image.

  However, a conventional vertical alignment type active matrix liquid crystal display device is configured such that a high voltage (about 15 to 20 V) gate signal is supplied to a TFT gate electrode, whereby the TFT gate electrode and the pixel electrode adjacent to the TFT are separated. A strong horizontal electric field along the substrate surface is generated between them, and the liquid crystal molecules in the region adjacent to the TFT of the pixel behave due to the influence of the horizontal electric field, so that the alignment of the liquid crystal molecules in each pixel is disturbed. Disturbances in orientation at each time give the display a rough feeling.

  An object of the present invention is to provide a vertical alignment type active matrix liquid crystal display element which can display a good quality image with less roughness and less disorder of alignment of liquid crystal molecules for each pixel. Is.

  The liquid crystal display element according to the present invention is provided on the inner surface of one of the pair of substrates opposed to each other with a predetermined gap and the inner surfaces of the pair of substrates facing each other, in the row direction and the column. A plurality of pixel electrodes arranged in a matrix in the direction, and a plurality of TFTs provided on the inner surface of the one substrate in the vicinity thereof in correspondence with the plurality of pixel electrodes and connected to the corresponding pixel electrodes, respectively A plurality of gates provided on the inner surface of the one substrate along one side of each pixel electrode row and one side of each pixel electrode column, respectively, for supplying gate signals and data signals to the TFTs in the rows and columns; Wiring and data wiring, provided on the inner surface of the other substrate, facing the plurality of pixel electrodes, on the inner surface of the one substrate, adjacent to at least the TFT around the plurality of pixel electrodes An auxiliary electrode that faces the counter electrode and generates an electric field of a predetermined value between the counter electrode and the inner surfaces of the pair of substrates, respectively, covering the electrode And a liquid crystal layer having negative dielectric anisotropy sealed in a gap between the pair of substrates.

  In the liquid crystal display element according to the present invention, the auxiliary electrode is formed on a substrate surface of the one substrate, the pixel electrode is formed on an insulating film provided to cover the auxiliary electrode, and the TFT The connection electrode that connects the electrode on the semiconductor film and the pixel electrode is preferably formed so that the portion intersecting the auxiliary electrode is narrower than the width of the electrode on the semiconductor film of the TFT.

  Further, in this liquid crystal display element, the pixel electrode is formed in a shape in which a part of the electrode edge adjacent to the TFT is separated from the TFT, and the electrode on the semiconductor film of the TFT and the pixel It is preferable that the connection electrode for connecting the electrode is formed so as to intersect the auxiliary electrode in a region corresponding to a portion of the pixel electrode that is separated from the TFT. The auxiliary electrode is preferably provided so as to correspond to at least an edge adjacent to the TFT and the gate wiring around the pixel electrode.

  More preferably, the auxiliary electrode is provided over the entire circumference of the pixel electrode. Further, it is preferable that the auxiliary electrode is set to a potential having the same value as the potential of the counter electrode, and a region where an electric field is not substantially applied is formed between the auxiliary electrode and the counter electrode.

  The auxiliary electrode is preferably formed integrally with a capacitor electrode that forms a compensation capacitor with the pixel electrode.

  In the liquid crystal display element of the present invention, it is preferable that a slit for dividing the pixel electrode into a plurality of electrode portions is provided in each of the plurality of pixel electrodes. In that case, it is preferable that extension portions corresponding to the slits of the plurality of pixel electrodes are formed in the auxiliary electrode.

  In the liquid crystal display element of the present invention, it is preferable that a plurality of protrusions respectively corresponding to the center portions of the plurality of pixel electrodes provided on the inner surface of the one substrate are provided on the inner surface of the other substrate.

  The liquid crystal display element according to the present invention has an inner surface of one substrate provided with a plurality of pixel electrodes, TFTs, gate wirings, and data wirings so as to correspond to at least a portion adjacent to the TFTs around the pixel electrodes. Since an auxiliary electrode for generating an electric field having a predetermined value is provided between the counter electrode and the counter electrode, the voltage of the gate signal applied to the gate electrode of the TFT is between the gate electrode and the pixel electrode. Therefore, the disturbance of the orientation of the liquid crystal molecules due to the influence of the lateral electric field due to the gate signal for each of the plurality of pixels composed of regions where the plurality of pixel electrodes and the counter electrode face each other, It is possible to display an image of good quality without a feeling of roughness.

  In the liquid crystal display element according to the present invention, the auxiliary electrode is formed on a substrate surface of the one substrate, the pixel electrode is formed on an insulating film provided to cover the auxiliary electrode, and the TFT The connection electrode that connects the electrode on the semiconductor film and the pixel electrode is preferably formed so that the portion intersecting the auxiliary electrode is narrower than the width of the electrode on the semiconductor film of the TFT. By doing so, the disorder of the alignment of the liquid crystal molecules in the pixel can be further reduced.

  Further, in this liquid crystal display element, the pixel electrode is formed in a shape in which a part of the electrode edge adjacent to the TFT is separated from the TFT, and the electrode on the semiconductor film of the TFT and the pixel It is preferable that the connection electrode for connecting the electrode is formed so as to intersect with the auxiliary electrode in a region corresponding to the portion of the pixel electrode that is separated from the TFT. By doing so, the liquid crystal in the pixel is formed. The disorder of molecular orientation can be almost eliminated. In addition, the auxiliary electrode is preferably provided so as to correspond to at least an edge adjacent to the TFT and the gate wiring around the pixel electrode, and in this way, in the region adjacent to the gate wiring of the pixel. The disorder of the alignment of the liquid crystal molecules can be eliminated.

  More preferably, the auxiliary electrode is provided over the entire circumference of the pixel electrode, so that the inter-substrate electric field around the pixel (the electric field between the auxiliary electrode and the counter electrode) can be increased. The liquid crystal molecules in the pixel are made to be the same over the circumference, and the liquid crystal molecules in the pixel are aligned with each other in accordance with the writing voltage applied between the pixel electrode and the counter electrode. Can be displayed.

  Further, it is preferable that the auxiliary electrode is set to a potential having the same value as the potential of the counter electrode, and a region where no electric field is substantially applied is formed between the auxiliary electrode and the counter electrode. The periphery of the pixel is in a substantially electric-free state over the entire circumference of the pixel, and the liquid crystal molecules in the pixel are more preferably tilted and aligned in correspondence with the writing voltage for each pixel, and further excellent quality Images can be displayed.

  In addition, the auxiliary electrode is preferably formed integrally with a capacitor electrode that forms a compensation capacitor between the auxiliary electrode and the pixel electrode, whereby a sufficient aperture ratio can be obtained.

  In the liquid crystal display element of the present invention, it is desirable to provide a slit for dividing the pixel electrode into a plurality of electrode portions, respectively, in the plurality of pixel electrodes. A plurality of regions respectively corresponding to the plurality of electrode portions divided by the slits of the pixel electrode are tilted and aligned corresponding to the write voltage, and display of a high quality image without display unevenness of each pixel is displayed. be able to.

  In that case, it is preferable to form extension portions corresponding to the slits of the plurality of pixel electrodes in the auxiliary electrode, respectively, so that the inter-substrate electric field around the plurality of regions of the pixel is reduced. It is possible to display a higher quality image by making the liquid crystal molecules in each pixel the same in accordance with the write voltage for each of the plurality of regions and by aligning the liquid crystal molecules in the same manner over the entire circumference of each region.

  In the liquid crystal display element of the present invention, it is desirable to provide a plurality of protrusions respectively corresponding to the center portions of the plurality of pixel electrodes provided on the inner surface of the one substrate on the inner surface of the other substrate. By doing so, it is possible to prescribe the direction of tilting due to the application of the write voltage of the liquid crystal molecules in the pixel so that it is tilted by the protrusion from the peripheral edge of the pixel toward the center of the pixel. The liquid crystal molecules in each pixel are regularly tilted and aligned, and a good image without unevenness can be displayed.

(First embodiment)
1 to 5 show a first embodiment of the present invention. FIG. 1 is a plan view of one pixel portion of one substrate of a liquid crystal display element, and FIGS. 2 and 3 are II-II in FIG. It is sectional drawing of the liquid crystal display element which follows a line and a III-III line.

  This liquid crystal display element is a vertical alignment type active matrix liquid crystal display element in which TFTs are used as active elements. As shown in FIGS. 1 to 3, a pair of transparent layers arranged opposite to each other with a predetermined gap therebetween. A plurality of transparent pixel electrodes 3 provided on the inner surface of one of the substrates 1 and 2 and the inner surfaces of the pair of substrates 1 and 2 facing each other and arranged in a matrix in the row and column directions; A plurality of TFTs 4 provided in the vicinity of the inner surface of the one substrate 1 so as to correspond to the plurality of pixel electrodes 3 and respectively connected to the corresponding pixel electrodes 3, and an inner surface of the one substrate 1; A plurality of gate lines 11 and data lines 12 are provided along one side of each pixel electrode row and one side of each pixel electrode column, and supply gate signals and data signals to the TFTs 4 in the rows and columns. And a single-film transparent counter electrode 15 which is provided on the inner surface of the other substrate 2 and faces the plurality of pixel electrodes 3, and covers the electrodes 3 and 15 on the inner surfaces of the pair of substrates 1 and 2, respectively. And a nematic liquid crystal layer 20 having negative dielectric anisotropy sealed in a gap between the pair of substrates 1 and 2.

  Hereinafter, one substrate on which the pixel electrode 3, the TFT 4, the gate wiring 11 and the data wiring 12 are provided is referred to as a TFT substrate, and the other substrate 2 on which the counter electrode 15 is provided is referred to as a counter substrate.

  The liquid crystal display element is a color image display element, and is opposed to a region between a plurality of pixels formed by a region where the plurality of pixel electrodes 3 and the counter electrode 15 face each other on the inner surface of the counter substrate 2. A black mask 16 having a lattice film shape and red, green, and blue color filters 17R, 17G, and 17B corresponding to the respective pixel columns are provided, and the counters are provided on the color filters 17R, 17G, and 17B. An electrode 15 is formed, and the vertical alignment film 19 is formed thereon.

  The plurality of TFTs 4 include a gate electrode 5 formed on the substrate surface of the TFT 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, An i-type semiconductor film 7 formed on the gate insulating film 6 so as to face the gate electrode 5 and a blocking insulating film 8 (not shown in FIG. 1) formed so as to cover the channel region of the semiconductor film 7. And a drain electrode 9 and a source electrode 10 formed on one side and the other side of the channel region of the semiconductor film 7 via an n-type semiconductor film (not shown).

  The gate wiring 11 is formed integrally with the gate electrode 5 of the TFT 4 on the substrate surface of the TFT substrate 1, and the data wiring 12 is formed on the gate insulating film 6 and on the drain electrode 9 of the TFT 4. And is integrally formed.

  The pixel electrode 3 is formed on the gate insulating film 6, and the source electrode 10 of the TFT 4 is connected via a connection electrode 10 a extending from the source electrode 10 onto the gate insulating film 6. Connected to the pixel electrode 3.

  The TFT 4 and the data wiring 12 are covered with an overcoat insulating film 13 (not shown in FIG. 1) formed on the inner surface of the TFT substrate 1 except for the portion corresponding to each pixel electrode 3. The vertical alignment film 18 is formed thereon.

  Further, the liquid crystal display element is provided on the inner surface of the TFT substrate 1 so as to correspond to at least a portion adjacent to the gate electrode 5 of the TFT 4 around the plurality of pixel electrodes 3. An electric field having a predetermined value lower than the voltage value of the gate signal supplied to the gate electrode 5 of the TFT 4 via the gate wiring 11 is generated between the counter electrode 15 and the counter electrode 15. An auxiliary electrode 14 is provided.

  The auxiliary electrode 14 is preferably provided so as to correspond to at least an edge adjacent to the gate electrode 5 and the gate wiring 11 of the TFT 4 around the pixel electrode 3, and further provided over the entire circumference of the pixel electrode 3. Is preferred.

  In this embodiment, the auxiliary electrode 14 is provided over the entire circumference of the pixel electrode 3. In FIG. 1, in order to make the drawing easier to see, a portion corresponding to the auxiliary electrode 14 is shaded in parallel.

  The auxiliary electrode 14 is formed integrally with a capacitor electrode that forms a compensation capacitor between the auxiliary electrode 14 and the pixel electrode 3, and also serves as the capacitor electrode.

  That is, the auxiliary electrode 14 is composed of a frame-shaped metal film provided on the substrate surface of the TFT substrate 1 so as to correspond to the entire circumference of the pixel electrode 3, and each side portion of the frame-shaped metal film is The inner edge of the pixel electrode 3 is opposed to the peripheral edge of the pixel electrode 3 with the gate insulating film 6 interposed therebetween, and the outer edge of the pixel electrode 3 extends outward.

  The inner edge portion of each side portion of the frame-shaped metal film is a capacitance electrode portion that forms a compensation capacitor having the gate insulating film 6 as a dielectric layer between the inner edge portion of the pixel electrode 3 and the peripheral edge portion of the pixel electrode 3. In addition, the outer side edge of each side of the frame-shaped metal film, that is, the portion that protrudes outward from the pixel electrode 3 faces the counter electrode 15, and is predetermined between the counter electrode 15. It is an auxiliary electrode part that forms a value electric field.

  The auxiliary electrode 14 is formed on the substrate surface of the TFT substrate 1, and the pixel electrode 3 is formed on the gate insulating film 6 provided to cover the auxiliary electrode 14, and the TFT 4 The connection electrode 10 a that connects the source electrode 10 on the semiconductor film 7 and the pixel electrode 3 extends from the source electrode 10 of the TFT 4 onto the gate insulating film 6 and is connected to the pixel electrode 3. The auxiliary electrode 14 faces the counter electrode 15 in a region other than the portion where the connection electrode 10a intersects.

  Therefore, in this embodiment, the width of the portion on the semiconductor film 7 of the TFT 4, that is, the TFT 4, is set so that the portion of the connection electrode 10 a intersecting the auxiliary electrode 14 does not exceed the allowable value. The width of the portion where the connection electrode 10a intersects the auxiliary electrode 14 is narrowed, and the area of the auxiliary electrode 14 facing the counter electrode 15 is lengthened.

  Further, in this embodiment, the pixel electrode 3 is formed in a shape in which a part of the electrode edge adjacent to the TFT 4 is separated from the TFT 4, and the source electrode 10 of the TFT 4 and the pixel electrode 3 are connected. The connection electrode 10a is formed so as to intersect the auxiliary electrode 14 in a region corresponding to a portion of the pixel electrode 3 that is separated from the TFT 4.

  In this embodiment, as shown in FIG. 1, among the electrode edges of the pixel electrode 3 adjacent to the TFT 4, the electrode edge on the corner side of the pixel electrode 3 is separated from the TFT 4. Another part (for example, the central part) of the electrode edge of the part adjacent to the TFT 4 of the pixel electrode 3 may be separated from the TFT 4. The auxiliary electrodes 14 respectively corresponding to the periphery of the plurality of pixel electrodes 3 are connected to each other at the end opposite to the gate wiring 11 side for each pixel electrode row, and the auxiliary electrodes 14 in each row. Are commonly connected to an auxiliary electrode connection wiring (not shown) provided in parallel with the data wiring 12 at one end or both ends outside the array region of the plurality of pixel electrodes 3.

  The pair of substrates 1 and 2 are bonded via a frame-shaped sealing material (not shown) surrounding the array region of the plurality of pixel electrodes 3, and the liquid crystal layer 20 is interposed between the pair of substrates 1 and 2. It is enclosed in a region surrounded by the sealing material.

  The liquid crystal molecules 20a of the liquid crystal layer 20 are substantially perpendicular to the substrates 1 and 2 due to the vertical alignment properties of the vertical alignment films 18 and 19 provided on the inner surfaces of the pair of substrates 1 and 2, respectively. Oriented.

  Although not shown, the TFT substrate 1 has a protruding portion that protrudes outward from the counter substrate 2 at one end in the row direction and one end in the column direction. A plurality of gate side driver connection terminals are formed in an array on the projecting portion, and a plurality of data side driver connection terminals are arrayed on the projecting portion in the column direction.

  The plurality of gate wirings 11 are led out to the row extending portions and connected to the plurality of gate side driver connection terminals, respectively, and the plurality of data wirings 12 are connected to the column extending portions. Are connected to the plurality of data-side driver connection terminals, and the auxiliary electrode connection wiring is led out to one or both of the protruding portions in the row direction and the column direction. It is connected to the reference potential terminal of the driver connection terminals.

  Further, the inner surface of the TFT substrate 1 is led to one or both of the row direction and column direction protruding portions from the vicinity of the corner portion of the substrate bonding portion by the sealing material, and the reference potential of the driver connection terminals. A counter electrode connection wiring connected to a terminal (which may be the same terminal as the terminal to which the auxiliary electrode connection wiring is connected or another reference potential terminal) is provided, and the counter electrode 15 provided on the inner surface of the counter substrate 2 is provided. Is connected to the counter electrode connection wiring at the substrate junction, and is connected to the reference potential terminal via the counter electrode connection wiring.

  In other words, in this embodiment, the potentials of the plurality of auxiliary electrodes 14 are set to the same value as the potential of the counter electrode 15 (reference potential), and substantially between these auxiliary electrodes 14 and the counter electrode 15. A region to which no electric field is applied is formed (a region where the electric field is zero).

  Further, polarizing plates 21 and 22 are respectively arranged on the outer surfaces of the pair of substrates 1 and 2 with their transmission axes directed in a predetermined direction. In this embodiment, the polarizing plates 21 and 22 are arranged so that their transmission axes are substantially orthogonal to each other so that the liquid crystal display element performs display in a normally black mode.

  This liquid crystal display element displays an image for each of a plurality of pixels by tilting the liquid crystal molecules 20a from the vertical alignment state by applying a write voltage between the pixel electrode 3 and the counter electrode 15.

  4 and 5 are a cross-sectional view and a plan view showing a tilted alignment state of the liquid crystal molecules 20a of one pixel portion of the liquid crystal display element. The liquid crystal molecules 20a are applied to each pixel by applying the write voltage. 4, the molecular long axis is directed in the direction along the equipotential line indicated by the broken line in FIG. 4, and the liquid crystal molecules 20 a in the central part of the pixel fall down in a spiral shape from the peripheral part of the pixel toward the central part. The liquid crystal molecules 20a positioned around the liquid crystal molecules 20a are aligned so as to stand up by the action of intermolecular forces acting on each other.

  The liquid crystal display element is disposed between the inner surface of the TFT substrate 1 and the counter electrode 15 provided on the counter substrate 2 so as to correspond to at least a portion adjacent to the TFT 4 around the plurality of pixel electrodes 3. Since the auxiliary electrode 14 for forming an electric field having a predetermined value is provided, the voltage of the gate signal applied to the gate electrode 5 of the TFT 4 is applied between the gate electrode 5 and the pixel electrode 3. Therefore, it is possible to eliminate the disorder of the alignment of the liquid crystal molecules 20a due to the influence of the lateral electric field by the gate signal for each of the plurality of pixels, and display a good quality image without a feeling of roughness.

  That is, in the liquid crystal display element, the auxiliary electrode 14 is provided on the inner surface of the TFT substrate 1 so as to correspond to at least a portion adjacent to the TFT 4 around the plurality of pixel electrodes 3, and the auxiliary electrode 14 and the counter electrode 15 are provided. Since an electric field having a predetermined value lower than the voltage value of the gate signal supplied to the gate electrode 5 of the TFT 4 is formed between the TFT 4 and the gate electrode 5 of the TFT 4 as in the conventional liquid crystal display element, The supply of the gate signal generates a strong lateral electric field along the substrate surface between the TFT gate electrode and the TFT adjacent portion of the pixel electrode, and the liquid crystal molecules in the region adjacent to the pixel TFT behave due to the influence of the lateral electric field. As a result, the alignment of the liquid crystal molecules for each pixel is not disturbed.

  However, as described above, the auxiliary electrode 14 faces the counter electrode 15 in a region other than the portion where the connection electrode 10a connecting the source electrode 10 and the pixel electrode 3 of the TFT 4 intersects. At the intersection of the connection electrodes 10a, an electric field based on a data signal supplied from the source electrode 10 of the TFT 4 to the pixel electrode 3 via the connection electrode 10a and a gate signal supplied to the gate electrode 5 of the TFT 4 are provided. However, since the regions where these electric fields are generated are extremely small, the disorder of the alignment of the liquid crystal molecules 20a in the region adjacent to the TFT 4 of the pixel due to the influence of the lateral electric power is small.

  In addition, in this embodiment, the portion of the connection electrode 10a that connects the source electrode 10 of the TFT 4 and the pixel electrode 3 that intersects the auxiliary electrode 14 is within a range in which the resistance value of the portion does not exceed an allowable value. Since the width of the portion of the TFT 4 on the i-type semiconductor film 7, that is, the channel width of the TFT 4, is narrowed, and the region of the auxiliary electrode 14 facing the counter electrode 15 is made long, the gate signal to the TFT 4 The generation region of the lateral electric field due to the supply can be further reduced, and accordingly, the disorder of the alignment of the liquid crystal molecules 20a in the pixel can be further reduced.

  Furthermore, in this embodiment, the pixel electrode 3 is formed in a shape in which a part of the electrode edge adjacent to the TFT 4 is separated from the TFT 4, and the source electrode 10 and the pixel electrode 3 of the TFT 4 are formed. Since the connection electrode 10a to be connected is formed so as to intersect with the auxiliary electrode 14 in a region corresponding to the portion of the pixel electrode 3 that is separated from the TFT 4, the connection electrode 10a intersects with the portion where the connection electrode 10a intersects. An electric field is hardly generated and the strength of the electric field can be reduced. Therefore, the disorder of the alignment of the liquid crystal molecules 20a in the pixel can be almost eliminated.

  In this embodiment, the auxiliary electrode 14 is provided corresponding to the edge adjacent to the TFT 4 and the gate wiring 11 around the pixel electrode 3, so that the region adjacent to the gate wiring 11 of the pixel is provided. The disorder of the alignment of the liquid crystal molecules 20a can be eliminated.

  Furthermore, in this embodiment, since the auxiliary electrode 14 is provided over the entire circumference of the pixel electrode 3, the inter-substrate electric field (electric field between the auxiliary electrode 14 and the counter electrode 15) around the pixel is It is the same over the entire circumference of the pixel, and the liquid crystal molecules 20a in the pixel are tilted well in accordance with the write voltage applied between the pixel electrode 3 and the counter electrode 15 for each pixel. A good quality image can be displayed.

  In addition, in this embodiment, the auxiliary electrode 14 is set to a potential having the same value as the potential of the counter electrode 15 (reference potential), and the electric field between the auxiliary electrode 14 and the counter electrode 15 is substantially zero. Since the region is formed, the periphery of the pixel is in a substantially no electric field state, that is, in a state where the liquid crystal molecules 20a are aligned substantially perpendicular to the surfaces of the substrates 1 and 2. The liquid crystal molecules 20a in the pixels can be aligned so as to fall from the peripheral edge toward the center for each pixel in correspondence with the writing voltage. Therefore, the liquid crystal molecules 20a are written to the pixels for each pixel. In accordance with the voltage, the image can be tilted more favorably and an image of better quality can be displayed. In this embodiment, since the auxiliary electrode 14 is formed integrally with a capacitor electrode that forms a compensation capacitor between the auxiliary electrode 14 and the pixel electrode 3, the compensation capacitor 14 is opposed to the peripheral portion of the pixel electrode 3. As in the case where a forming electrode is provided and an auxiliary electrode for forming an electric field having a predetermined value is provided between the forming electrode and the counter electrode, the compensation capacitor forming electrode and the gate wiring and data wiring outside thereof are provided. Therefore, it is not necessary to reduce the area of the pixel electrode in order to secure a space for forming the auxiliary electrode between them, so that a sufficient aperture ratio can be obtained.

(Second Embodiment)
6 to 9 show a second embodiment of the present invention. FIG. 6 is a plan view of one pixel portion of one substrate (TFT substrate) of the liquid crystal display element, and FIG. It is sectional drawing of the liquid crystal display element which follows a VII line.

  In the liquid crystal display element of this embodiment, those corresponding to the liquid crystal display element of the first embodiment described above are denoted by the same reference numerals, and description of the same elements is omitted.

  In the liquid crystal display element of this embodiment, each of the plurality of pixel electrodes 3 provided on the inner surface of the TFT substrate 1 is provided with one slit 23a along the row direction and one slit 23b along the column direction. 3, the plurality of pixel electrodes 3 are divided into a plurality (four in this embodiment) of electrode portions 3a, 3b, 3c, and 3b having substantially the same area. The configuration is the same as that of the liquid crystal display element of the first embodiment.

  Each of the slits 23a and 23b is formed in such a length that both ends thereof are located slightly inside the electrode edge of the pixel electrode 3, and each of the electrode portions 3a and 23b divided by the slits 23a and 23b is formed. 3b, 3c and 3b are connected to each other at the edge portions on both ends of the slits 23a and 23b of the pixel electrode 3.

  In this embodiment, an electric field having a predetermined value (an electric field of 0 V in this embodiment) is formed between the TFT substrate 1 and the counter electrode 15 provided on the counter substrate 2. Extension portions 14 a and 14 b corresponding to the slits 23 a and 23 b of the plurality of pixel electrodes 3 are formed on the auxiliary electrode 14.

  The auxiliary electrode 14 is formed integrally with a capacitor electrode that forms a compensation capacitor between the auxiliary electrode 14 and the pixel electrode 3, as in the first embodiment described above. Therefore, a compensation capacitance having a sufficient capacitance value can be formed at a portion of the auxiliary electrode 14 facing the peripheral edge of the pixel electrode 3.

  Therefore, in this embodiment, the extension portions 13a and 13b of the auxiliary electrode 14 are arranged on both sides of the slits 23a and 23b of the pixel electrode 3 as shown in FIGS. It is formed to have a width that is opposed to the edge portion with a very small overlap width, and the light shielding area by the extension portions 13a and 13b of the auxiliary electrode 14 is made as small as possible to ensure a sufficient aperture ratio.

  8 and 9 are a cross-sectional view and a plan view showing a tilted alignment state of the liquid crystal molecules 20a of one pixel portion of the liquid crystal display element of this embodiment, and the liquid crystal molecules 20a include slits 23a, As shown in FIG. 8 by a broken line, a write voltage is applied between the pixel electrode 3 and the counter electrode 15 for each region corresponding to each of the plurality of electrode portions 3a, 3b, 3c, and 3d divided by 23b. The molecular long axis is directed in a direction along the equipotential line, and the liquid crystal molecules 20a in the central portion of the region are located in the periphery thereof. The liquid crystal molecules 20a are aligned so as to stand up by the action of intermolecular forces acting on each other.

  In the liquid crystal display element of this embodiment, since the plurality of pixel electrodes 3 are provided with slits 23a and 23b for dividing the pixel electrode 3 into a plurality of electrode portions, respectively, the liquid crystal display of the first embodiment described above. In addition to the effect of the element, the liquid crystal molecules 20a in the pixels are tilted and aligned in correspondence with the writing voltage for each of the plurality of regions, and display of a high quality image is eliminated without display unevenness of each pixel. Can do.

  In addition, in this embodiment, the auxiliary electrodes 14 are formed with the extension portions 14a and 14b corresponding to the slits 23a and 23b of the plurality of pixel electrodes 3, respectively. The inter-substrate electric field (the electric field between the auxiliary electrode 14 and its extended portions 14a and 14b and the counter electrode 15) can be made the same over the entire circumference of each region, so that the liquid crystal molecules 20a in the pixel are A higher-quality image can be displayed by uniformly aligning the plurality of regions in accordance with the writing voltage.

  In this embodiment, a region where the electric field is substantially zero is formed between the auxiliary electrode 14 and its extension portions 14a and 14b and the counter electrode 15 as in the first embodiment. Therefore, the periphery of the plurality of regions of the pixel is substantially in the absence of electric field over the entire circumference, and the liquid crystal molecules 20a of the plurality of regions are made uniform corresponding to the write voltage for each region. It is possible to display an image of even better quality by tilting and tilting.

  In the second embodiment, the auxiliary electrode 14 is formed with extension portions 14a and 14b corresponding to the slits 23a and 23b of the plurality of pixel electrodes 3, respectively. In this case as well, the liquid crystal molecules 20a in the pixels are tilted and aligned in correspondence with the write voltage for each of the plurality of regions, thereby eliminating the display unevenness of each pixel and producing a high-quality image. Can be displayed.

  In the second embodiment, each of the plurality of pixel electrodes 3 intersects one slit 23 a along the row direction and one slit 23 b along the column direction at the center of the pixel electrode 3. However, the direction and the number of slits for dividing the pixel electrode 3 into a plurality of electrode portions may be arbitrary.

(Third embodiment)
10 to 13 show a third embodiment of the present invention. FIG. 10 is a plan view of one pixel portion of one substrate (TFT substrate) of the liquid crystal display element. FIG. 11 is a plan view of the liquid crystal display element. It is sectional drawing which follows the XI-XI line in FIG.

  In the liquid crystal display element of this embodiment, those corresponding to the liquid crystal display element of the first embodiment described above are denoted by the same reference numerals, and description of the same elements is omitted.

  In the liquid crystal display element of this embodiment, a plurality of transparent protrusions 24 respectively corresponding to the center portions of the plurality of pixel electrodes 3 provided on the TFT substrate 1 are provided on the inner surface of the counter substrate 2. The configuration is the same as that of the liquid crystal display element of the first embodiment.

  The plurality of protrusions 24 are formed of an insulating material such as a photosensitive resin on the three color filters 17R, 17G, and 17B of red, green, and blue formed on the inner surface of the counter substrate 2. The electrode 15 is formed in a shape that covers the protrusion 24 and that a portion on the protrusion 24 protrudes along the surface of the protrusion 24.

  The vertical alignment film 19 on the inner surface of the counter substrate 2 is formed to include a portion on the protrusion 24, and the liquid crystal molecules 20 a corresponding to the protrusion 24 include liquid crystal molecules in the vicinity of the protrusion 24. 20a is oriented with its molecular long axis oriented in a direction substantially perpendicular to the surface of the protrusion 24 (hemispherical surface), and the liquid crystal molecules 20a in the vicinity of the TFT substrate 1 have their molecular long axes with respect to the substrates 1 and 2; In a state of being oriented in a substantially vertical direction.

  In this embodiment, the protrusion 24 is formed in a hemispherical shape, and among the liquid crystal molecules 20a in the vicinity of the counter substrate 2 of the liquid crystal layer 20, the liquid crystal molecules 20a around the protrusion 24 are hemispherical as shown in FIG. The protrusion 24 is oriented in an orientation state in which the molecular long axis is oriented in a direction along the radiation from the center of curvature of the protrusion 24.

  12 and 13 are a cross-sectional view and a plan view showing a tilted alignment state of the liquid crystal molecules 20a of one pixel portion of the liquid crystal display element of this embodiment, and the liquid crystal molecules 20a are provided for the pixel electrode 3 for each pixel. And the counter electrode 15 are applied with a write voltage to fall down from the periphery of the pixel in a spiral shape toward the center, and substantially perpendicular to the surface of the protrusion 24 at the center of the pixel. Align so that

  In the liquid crystal display element of this embodiment, a plurality of protrusions 24 corresponding to the center portions of the plurality of pixel electrodes 3 of the TFT substrate 1 are provided on the inner surface of the counter substrate 2, and the liquid crystal molecules 20 a in the vicinity of the protrusions 24 are provided. Since the molecular long axis is oriented in a direction substantially perpendicular to the surface of the protrusion 24, the tilting direction due to the application of the write voltage of the liquid crystal molecules 20a of each pixel is caused by the protrusion 24. The pixel can be defined to fall from the peripheral edge of the pixel toward the center of the pixel. Therefore, the liquid crystal molecules 20a of the pixels are regularly tilted and aligned, and display irregularities of the pixels are eliminated, thereby achieving high quality. An image can be displayed.

  Further, when the protrusion 24 made of an insulating material such as a photosensitive resin is provided on the counter electrode 15, electric charges are applied to the protrusion 24 when a write voltage is applied between the pixel electrode 3 and the counter electrode 15. Even after charging and no electric field between the pixel electrode 3 and the counter electrode 15, the liquid crystal molecules 20 a cause a display burn-in phenomenon in which the liquid crystal molecules 20 a are tilted to some extent by the charging voltage of the protrusions 24. In this embodiment, since the counter electrode 15 is formed so as to cover the protrusion 24, the charge to the protrusion 24 can be eliminated, and the display burn-in phenomenon can be prevented.

  In this embodiment, the protrusion 24 is formed in a hemispherical shape. However, the protrusion 24 is not limited to a hemispherical shape, and is formed, for example, in a conical shape or a truncated conical shape having a smaller diameter toward the protruding end. May be.

1 is a plan view of one pixel portion of one substrate of a liquid crystal display element showing a first embodiment of the present invention. Sectional drawing of the liquid crystal display element which follows the II-II line | wire of FIG. Sectional drawing of the liquid crystal display element which follows the III-III line | wire of FIG. FIG. 3 is a cross-sectional view showing a tilted alignment state of liquid crystal molecules in one pixel portion of the first embodiment. FIG. 3 is a plan view showing a tilted alignment state of liquid crystal molecules in one pixel portion of the first embodiment. The top view of one pixel part of one board | substrate of the liquid crystal display element which shows 2nd Example of this invention. Sectional drawing of the liquid crystal display element which follows the VII-VII line of FIG. Sectional drawing which shows the fall alignment state of the liquid crystal molecule of one pixel part of a 2nd Example. FIG. 10 is a plan view showing a tilted alignment state of liquid crystal molecules in one pixel portion of the second embodiment. 1 is a plan view of one pixel portion of one substrate of a liquid crystal display element showing a first embodiment of the present invention. Sectional drawing of the liquid crystal display element which follows the XI-XI line of FIG. FIG. 6 is a cross-sectional view illustrating a tilted alignment state of liquid crystal molecules in one pixel portion according to a third embodiment. FIG. 10 is a plan view showing a tilted alignment state of liquid crystal molecules in one pixel portion of the third embodiment.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1, 2 ... Substrate, 3 ... Pixel electrode, 4 ... TFT (Thin film transistor), 5 ... Gate electrode, 6 ... Gate insulating film, 7 ... i-type semiconductor film, 9 ... Drain electrode, 10 ... Source electrode, 10a ... Connection electrode , 11 ... gate wiring, 12 ... data wiring, 13 ... overcoat insulating film, 14 ... auxiliary electrode, 15 ... counter electrode, 16 ... black mask, 17R, 17G, 17B ... color filter, 18, 19 ... vertical alignment film, 20 ... liquid crystal layer, 20a ... liquid crystal molecule, 21, 22 ... polarizing plate, 23a, 23b ... slit, 24 ... projection.

Claims (10)

A pair of substrates opposed to each other with a predetermined gap;
A plurality of pixel electrodes provided on an inner surface of one of the pair of substrates facing each other and arranged in a matrix in a row direction and a column direction;
A plurality of thin film transistors provided on the inner surface of the one substrate so as to correspond to the plurality of pixel electrodes, respectively, and connected to the corresponding pixel electrodes;
A plurality of gate wirings provided on the inner surface of the one substrate along one side of each pixel electrode row and one side of each pixel electrode column and supplying gate signals and data signals to the thin film transistors in the rows and columns. And data wiring,
A counter electrode provided on the inner surface of the other substrate and facing the plurality of pixel electrodes;
The inner surface of the one substrate is provided so as to correspond to at least a portion adjacent to the thin film transistor around each of the plurality of pixel electrodes, is opposed to the counter electrode, and has a predetermined value between the counter electrode. An auxiliary electrode for generating an electric field;
Vertical alignment films provided on the inner surfaces of the pair of substrates so as to cover the electrodes,
A liquid crystal layer having negative dielectric anisotropy enclosed in a gap between the pair of substrates;
A liquid crystal display element comprising:   The auxiliary electrode is formed on the substrate surface of one substrate, the pixel electrode is formed on an insulating film provided to cover the auxiliary electrode, and the electrode on the semiconductor film of the thin film transistor is connected to the pixel electrode. 2. The liquid crystal display element according to claim 1, wherein the connecting electrode is formed such that a portion intersecting the auxiliary electrode is narrower than a width of the electrode on the semiconductor film of the thin film transistor.   The pixel electrode is formed in a shape in which a part of the electrode edge adjacent to the thin film transistor is separated from the thin film transistor, and the connection electrode that connects the electrode on the semiconductor film of the thin film transistor and the pixel electrode is the pixel electrode The liquid crystal display element according to claim 2, wherein the liquid crystal display element is formed so as to intersect with the auxiliary electrode in a region corresponding to a portion separated from the thin film transistor.   The liquid crystal display element according to claim 1, wherein the auxiliary electrode is provided so as to correspond to at least an edge adjacent to the thin film transistor and the gate wiring around the pixel electrode.   The liquid crystal display element according to claim 1, wherein the auxiliary electrode is provided over the entire circumference of the pixel electrode.   5. The auxiliary electrode is set to a potential substantially equal to the potential of the counter electrode, and forms a region where no electric field is substantially applied between the auxiliary electrode and the counter electrode. The liquid crystal display element in any one of -5.   The liquid crystal display element according to claim 1, wherein the auxiliary electrode is formed integrally with a capacitor electrode that forms a compensation capacitor between the auxiliary electrode and the pixel electrode.   The liquid crystal display element according to claim 1, wherein each of the plurality of pixel electrodes is provided with a slit for dividing the pixel electrode into a plurality of electrode portions.   The liquid crystal display element according to claim 8, wherein the auxiliary electrode is formed with extensions corresponding to the slits of the plurality of pixel electrodes.   2. The liquid crystal display element according to claim 1, wherein a plurality of protrusions respectively corresponding to central portions of a plurality of pixel electrodes provided on the inner surface of the one substrate are provided on the inner surface of the other substrate.

Images