JP4853533B2 - Liquid crystal display element - Google Patents

Description

  The present invention relates to a vertical alignment type liquid crystal display element.

  The vertical alignment type liquid crystal display element includes a plurality of pixel electrodes arranged in a matrix on the inner surface of one of the opposing inner surfaces of a pair of substrates facing each other with a gap, and the plurality of pixels A plurality of thin film transistors provided corresponding to the electrodes and connected to the corresponding pixel electrodes, a plurality of scanning lines and signal lines for supplying gate signals and data signals to the thin film transistors, and an inner surface of the other substrate, A counter electrode for forming a plurality of pixels is provided by regions facing each of the plurality of pixel electrodes, a vertical alignment film is provided on each inner surface of the pair of substrates, and a negative dielectric anisotropy is formed in a gap between the pair of substrates. The liquid crystal layer having the property is enclosed (see Patent Document 1).

Japanese Patent No. 2565639

  In the vertical alignment type liquid crystal display element, liquid crystal molecules are tilted from a vertical alignment state by applying a voltage between the electrodes for each of a plurality of pixels including regions where a plurality of pixel electrodes and a counter electrode face each other. The liquid crystal molecules of each pixel are aligned so as to fall down toward the electrode surface when the voltage is applied.

  However, in the conventional vertical alignment type liquid crystal display element, the direction in which the liquid crystal molecules are tilted by application of a voltage is unstable. For this reason, the tilted alignment state of the liquid crystal molecules in each pixel varies, and the display is rough.

  An object of the present invention is to provide a vertical alignment type liquid crystal display element capable of stably aligning and aligning liquid crystal molecules of each pixel by applying a voltage, and displaying a good quality image without a feeling of roughness. Is.

The liquid crystal display element of the present invention is arranged so that the first substrate and the second substrate face each other through a liquid crystal layer made of a liquid crystal having a negative dielectric anisotropy,
A liquid crystal display element in which a pixel electrode is divided into a plurality of electrode portions for each display pixel, and the pixel electrode is connected to a thin film transistor for each display pixel ,
It is arranged at a position corresponding to the center of each electrode part, and has a convex part formed at a height lower than the thickness of the liquid crystal layer,
The convex portion is
A gate insulating film covering the gate of the thin film transistor;
A plurality of insulating layers formed on the gate insulating film so as to have a shape smaller than the electrode portion and gradually decreasing from the lower layer toward the upper layer;
A semiconductor film or a metal film, which is disposed between the insulating layers adjacent to each other above and below and formed in a shape larger than the insulating film in contact with the upper layer side;
It is characterized by having.
Further, the liquid crystal display element of the present invention is arranged so that the first substrate and the second substrate face each other through a liquid crystal layer made of a liquid crystal having a negative dielectric anisotropy,
A liquid crystal display element formed such that a pixel electrode having a plurality of electrode portions for dividing the alignment direction of the liquid crystal layer is connected to a thin film transistor for each display pixel,
It is arranged at a position corresponding to the center of each electrode part, and has a convex part formed at a height lower than the thickness of the liquid crystal layer,
The convex portion is
A gate insulating film covering the gate of the thin film transistor;
A plurality of insulating layers formed on the gate insulating film so as to have a shape smaller than the electrode portion and gradually decreasing from the lower layer toward the upper layer;
A semiconductor film or a metal film, which is disposed between the insulating layers adjacent to each other above and below and formed in a shape larger than the insulating film in contact with the upper layer side;
It is characterized by having.
Further, the liquid crystal display element of the present invention is arranged so that the first substrate and the second substrate face each other through a liquid crystal layer made of a liquid crystal having a negative dielectric anisotropy,
A liquid crystal display element formed such that a pixel electrode provided with a plurality of slits for dividing the alignment direction of the liquid crystal layer is connected to a thin film transistor for each display pixel,
It is disposed at a position corresponding to the center between two adjacent slits, and has a convex portion formed at a height lower than the thickness of the liquid crystal layer,
The convex portion is
A gate insulating film covering the gate of the thin film transistor;
A plurality of insulating layers formed on the gate insulating film so as to have a shape smaller than the pixel electrode and gradually decreasing from the lower layer toward the upper layer;
A semiconductor film or a metal film, which is disposed between the insulating layers adjacent to each other above and below and formed in a shape larger than the insulating film in contact with the upper layer side;
It is characterized by having.
Further, the liquid crystal display element of the present invention is arranged so that the first substrate and the second substrate face each other through a liquid crystal layer made of a liquid crystal having a negative dielectric anisotropy,
A pixel electrode is connected to the thin film transistor for each display pixel,
A liquid crystal display device in which the convex portion of the linear shape for dividing the orientation direction of the liquid crystal layer is formed on the display each pixel in a region corresponding to the pixel electrode,
The convex portion is
A gate insulating film covering the gate of the thin film transistor;
A plurality of insulating layers formed on the gate insulating film so as to have a shape smaller than the pixel electrode and gradually decreasing from the lower layer toward the upper layer;
A semiconductor film or a metal film that is disposed between the insulating layers adjacent to each other above and below and formed in a shape larger than the insulating film in contact with the upper layer side, and
The liquid crystal layer is formed at a height lower than the thickness of the liquid crystal layer.

According to the present invention , it is possible to display a good quality image without a rough feeling.

1 is a plan view of a part of one substrate of a liquid crystal display device showing a first embodiment of the present invention; The expanded sectional view which follows the II-II line | wire in FIG. 1 of the liquid crystal display element of a 1st Example. The expanded sectional view which follows the III-III line | wire in FIG. 1 of the liquid crystal display element of a 1st Example. FIG. 3 is a cross-sectional view schematically showing an alignment state of liquid crystal molecules when no voltage is applied between electrodes in one pixel of the liquid crystal display element of the first embodiment. Sectional drawing which showed typically the orientation state of the liquid crystal molecule when a voltage is applied between the electrodes in one pixel of the liquid crystal display element of a 1st Example. The top view which showed typically the orientation state of the liquid crystal molecule when a voltage is applied between the electrodes in one pixel of the liquid crystal display element of a 1st Example. The top view of a part of one board | substrate of the liquid crystal display element which shows 2nd Example of this invention. The top view which showed typically the orientation state of the liquid crystal molecule when a voltage is applied between the electrodes in one pixel of the liquid crystal display element of a 2nd Example. Sectional drawing of a part of one board | substrate of the liquid crystal display element which shows the 3rd Example of this invention. Sectional drawing of a part of one board | substrate of the liquid crystal display element which shows the modification of a 3rd Example. Sectional drawing of a part of one board | substrate of the liquid crystal display element which shows the 4th Example of this invention. The top view of a part of one board | substrate of the liquid crystal display element which shows the 5th Example of this invention. The expanded sectional view which follows the XIII-XIII line | wire in FIG. 12 of the liquid crystal display element of a 5th Example. Sectional drawing which showed typically the orientation state of the liquid crystal molecule when a voltage is not applied between the electrodes in one pixel of the liquid crystal display element of a 5th Example. Sectional drawing which showed typically the orientation state of the liquid crystal molecule when a voltage is applied between the electrodes in one pixel of the liquid crystal display element of a 5th Example. The top view of a part of one board | substrate of the liquid crystal display element which shows the 6th Example of this invention.

(First embodiment)
1 to 6 show a first embodiment of the present invention. FIG. 1 is a plan view of a part of one substrate of a liquid crystal display element, and FIGS. 2 and 3 are II views of the liquid crystal display element in FIG. It is an expanded sectional view which follows the -II line and the III-III line.

  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. 3, a pair of facing each other with a predetermined gap therebetween. Of the mutually opposing inner surfaces of the transparent substrates 1 and 2 and the pair of substrates 1 and 2, one substrate, for example, the substrate opposite to the display viewing side (upper side in FIGS. 2 and 3) (hereinafter, rear A plurality of transparent pixel electrodes 3 arranged in a matrix in the row direction (left-right direction in FIG. 1) and column direction (up-down direction in FIG. 1) on the inner surface of the substrate 1, and the rear substrate 1 And a plurality of TFTs 5 connected to the corresponding pixel electrodes 3, and provided on the inner surface of the rear substrate 1, and gate signals and data signals are supplied to the TFTs 5. A plurality of scanning lines 14 and signal lines 15 to be supplied, and an inner surface of the rear substrate 1 are provided corresponding to the respective central portions of the plurality of pixel electrodes 3 and correspond to other regions of the pixel electrodes 3. A plurality of convex portions 13 projecting from the inner surface of the substrate and an inner surface of the other substrate, that is, an observation-side substrate (hereinafter referred to as a front substrate) 2, and a plurality of regions are respectively provided to face the plurality of pixel electrodes 3. In the gap between the pair of substrates 1 and 2, the single-layer transparent counter electrode 20 that forms the pixel 28, the vertical alignment films 25 and 26 provided on the inner surfaces of the pair of substrates 1 and 2, respectively. And an encapsulated liquid crystal layer 27 having negative dielectric anisotropy.

  The plurality of TFTs 5 include a gate electrode 6 formed on the substrate surface of the rear substrate 1 and a transparent gate insulating film 7 that covers the gate electrode 6 and is formed over the entire region of the plurality of pixel electrodes 3. And an i-type semiconductor film 8 formed on the gate insulating film 7 so as to face the gate electrode 6, and a blocking insulating film formed on a central portion serving as a channel region of the i-type semiconductor film 8. 9, a drain electrode 11D and a source electrode 11S formed on one side and the other side of the i-type semiconductor film 8 via an n-type semiconductor film 10, and an overcoat insulating film formed thereon It consists of twelve. In FIG. 1, the overcoat insulating film 12 and the vertical alignment film 25 are omitted.

  The plurality of scanning lines 14 are arranged on the plate surface of the rear substrate 1 along one side of each pixel electrode row, and the gate electrodes 6 of the plurality of TFTs 5 respectively corresponding to the plurality of pixel electrodes 3 in each row. And is integrally formed.

  The plurality of signal lines 15 are arranged on the gate insulating film 7 along one side of each pixel electrode column, and the drains of the plurality of TFTs 5 respectively corresponding to the plurality of pixel electrodes 3 in each column. It is formed integrally with the electrode 11D and is covered with the overcoat insulating film 12 of the TFT 5.

  The plurality of pixel electrodes 3 are formed on the gate insulating film 7 so that the TFT connection portions of the pixel electrodes 3 are stacked on the overcoat insulating film 12. The contact hole is connected to the source electrode 11S of the TFT5.

  Each of the plurality of pixel electrodes 3 is formed in an elongated rectangular shape whose width in the row direction is substantially an integer of the width in the column direction, for example, substantially 1/3. It consists of a transparent conductive film such as an ITO film provided with slits 4 that are divided into a plurality of substantially square (three in this embodiment) electrode portions 3a, 3b, 3c arranged in the longitudinal direction, The convex portion 13 corresponds to a central portion (square central portion) of three electrode portions (hereinafter referred to as square electrode portions) 3a, 3b, 3c formed in a substantially square shape of the pixel electrode 3, respectively. Is provided.

  The slit 4 of the pixel electrode 3 is provided in parallel to the row direction from near one side edge of the pixel electrode 3 to the other side edge, and each of the electrode portions 3a, 3b, 3c They are connected to each other at a portion between one side edge of the electrode 3 and the end of the slit 4.

  The convex portion 13 is made of a laminated film of the same film as all or part of the plurality of films 6, 7, 8, 9, 10, 11 D and 11 S, 12 constituting the TFT 5.

  In this embodiment, the convex portion 13 is made of the same film as all of the plurality of films constituting the TFT 5, that is, the lower metal film 6 a made of the same metal film as the gate electrode 6 and the scanning line 14, and the gate insulation. A lower semiconductor film 8a, an intermediate insulating film 9a, an upper semiconductor film 10a made of the same semiconductor film or insulating film as the film 7, the i-type semiconductor film 8, the blocking insulating film 9, and the n-type semiconductor film 10, and the drain electrode 11D. The upper metal film 11a made of the same metal film as the source electrode 11S and the upper insulating film 12a made of the same insulating film as the overcoat insulating film 12 are formed.

  Note that the gate insulating film 7 in the laminated film forming the convex portion 13 is formed over the entire arrangement region of the plurality of pixel electrodes 3, and thus the convex portion 13 is formed on the pixel electrode 3. With respect to the inner surface of the substrate corresponding to the other region, that is, the film surface of the region other than the portion corresponding to the convex portion 13 in the region corresponding to the pixel electrode 3 of the gate insulating film 7, the lower metal film 6a, The lower semiconductor film 8a, the intermediate insulating film 9a, the upper semiconductor film 10a, the upper metal film 11a, and the upper insulating film 12a protrude by a height corresponding to the total value of the respective film thicknesses.

  In this embodiment, the lower metal film 6a is formed in a circular film having a predetermined diameter, and the lower semiconductor film 8a is formed with respect to the diameter of the raised portion of the gate insulating film 7 on the lower metal film 6a. The convex portion is formed by sequentially decreasing the diameter of the three-layer film of the intermediate insulating film 9a and the upper semiconductor film 10a, the diameter of the upper metal film 11a, and the diameter of the upper insulating film 12a at a predetermined ratio. 13 is formed in a substantially truncated cone shape (a truncated cone shape having a stepped peripheral surface) having a circular planar shape and gradually decreasing in diameter from the base to the top.

  The pixel electrode 3 is formed on the gate insulating film 7 so as to cover the convex portion 13 and a portion corresponding to the convex portion 13 is formed on a portion other than the convex portion 13 (on the gate insulating film 7. The vertical alignment film 25 is formed over the entire arrangement region of the plurality of pixel electrodes 3.

  Further, on the inner surface of the rear substrate 1, a capacitor electrode 16 that forms a compensation capacitor 19 with the plurality of pixel electrodes 3 is further provided. In FIG. 1, in order to easily distinguish the capacitive electrodes 16, the portions corresponding to the capacitive electrodes 16 are shaded in parallel.

  The capacitor electrode 16 is made of a transparent conductive film such as an ITO film, and is formed on the plate surface of the rear substrate 1 so as to correspond to the peripheral portion excluding the TFT connection portion of the pixel electrode 3 and the slit 4. The gate insulating film 7 is opposed to the peripheral edge portions of the three square electrode portions 3a, 3b, 3c of the pixel electrode 3 with the gate insulating film 7 interposed therebetween, and the gate insulating film 7 is interposed between the pixel electrode 3 and the dielectric layer. Compensation capacitor 19 is formed.

  Note that the inner peripheral edge of the frame-shaped portion corresponding to the peripheral edge of the pixel electrode 3 is opposed to the peripheral edge of the pixel electrode 3, and the outer peripheral edge of the frame-shaped portion is the outer peripheral edge of the pixel electrode 3. Extending outward, both side edges of the part corresponding to the slit 4 are formed to have a width facing opposite edges of the square electrode parts 3a, 3b, 3c of the pixel electrode 3, The compensation capacitor 19 is formed by a portion of the capacitor electrode 16 facing the pixel electrode 3.

  The capacitor electrodes 16 respectively corresponding to the plurality of pixel electrodes 3 are integrally connected to each pixel electrode row on the side opposite to the TFT connection side of the pixel electrode 3, and the capacitor electrodes 16 of each row are further connected. Are commonly connected to a capacitor electrode connection line (not shown) provided in parallel with the signal line 15 at one end or both ends outside the array region of the plurality of pixel electrodes 3.

  On the other hand, on the inner surface of the front substrate 2, a plurality of pixels 28 having regions in which a plurality of pixel electrodes 3 provided on the inner surface of the rear substrate 1 and a counter electrode 20 provided on the inner surface of the front substrate 2 face each other. And a color filter 22R, 22G, 22B of three colors of red, green, and blue respectively corresponding to the plurality of pixels 28, and the color filters 22R, 22G, The counter electrode 20 is formed on 22B, and the vertical alignment film 26 is formed thereon.

  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, and are surrounded by the sealing material between the substrates 1 and 2. A liquid crystal layer 27 made of nematic liquid crystal having negative dielectric anisotropy is sealed in the gap.

  Although not shown, the rear substrate 1 has a protruding portion that protrudes outward from the front substrate 2 at both or one end in the row direction and the column direction, and the plurality of scanning lines. 14 and the signal line 15 are respectively connected to a plurality of driver connection terminals arranged in the overhanging portion, and the capacitor electrode connection lines in which the capacitor electrodes 16 of the respective rows are commonly connected are connected to the overhanging portion in the plurality of the plurality of driver connecting terminals. It is connected to the capacitor electrode terminals arranged together with the driver connection terminals.

  Further, on the inner surface of the rear substrate 1, a counter electrode terminal (the same terminal as the capacitor electrode terminal) that is led out from the vicinity of the corner portion of the substrate bonding portion by the sealing material to the protruding portion and arranged side by side with the driver connection terminal Or a different terminal may be provided), and a counter electrode connection line connected to the inner surface of the front substrate 2 is connected to the counter electrode connection line at the substrate bonding portion, The counter electrode terminal is connected to the counter electrode terminal.

  Although not shown in the figure, the liquid crystal display element includes a pair of polarizing plates respectively disposed on the outer surfaces of the pair of substrates 1 and 2. The liquid crystal display element is of a normally black mode in which, for example, the display is black when no voltage is applied between the pixel electrode 3 and the counter electrode 20, and the pair of polarizing plates are respectively The transmission axes are arranged substantially perpendicular to each other.

  In this liquid crystal display element, for each of a plurality of pixels 28 composed of regions where the plurality of pixel electrodes 3 and the counter electrode 20 face each other, a voltage is applied between the electrodes 3 and 20 to bring the liquid crystal molecules from a vertically aligned state. The liquid crystal molecules of each pixel 28 are aligned so as to fall from the edge of the pixel 28 toward the center by applying the voltage.

  FIG. 4 is a cross-sectional view schematically showing the alignment state of liquid crystal molecules when no voltage is applied between the electrodes 3 and 20 in one pixel 28 of the liquid crystal display element, and FIG. FIG. 6 is a cross-sectional view schematically showing an alignment state of liquid crystal molecules when a voltage is applied between the electrodes 3 and 20 in FIG. 6, and FIG. 6 shows a state in which a voltage is applied between the electrodes 3 and 20 in the one pixel 28. It is the top view which showed typically the orientation state of the liquid crystal molecule. 4 and 5, the convex portion 13 is simplified.

  As shown in FIG. 4, when no voltage is applied between the electrodes 3 and 20, the liquid crystal molecules 27a of the liquid crystal layer 27 are formed on the vertical alignment films 25 and 26 provided on the inner surfaces of the pair of substrates 1 and 2, respectively. Due to the vertical alignment property, the substrate is oriented substantially perpendicularly to the surfaces of the substrates 1 and 2 in a region other than the portion corresponding to the convex portion 13, and the portion on the rear substrate 1 side in the portion corresponding to the convex portion 13. The liquid crystal molecules 27a in the vicinity of the convex portion 13 are aligned with the molecular major axis in a direction substantially perpendicular to the top and peripheral surfaces of the convex portion 13, and the liquid crystal molecules 27a in the vicinity of the front substrate 2 are It is oriented in a state of being oriented substantially perpendicular to the front substrate 2 surface.

  In the liquid crystal display element, the plurality of pixel electrodes 3 are each formed into an elongated rectangular shape, and a plurality of (three) electrode portions 3a each having a substantially square shape in which the rectangular shape is arranged in the longitudinal direction. A plurality of square electrode portions 3a, 3b, 3b of the pixel electrode 3 formed on the inner surface of the substrate 1 after the plurality of pixel electrodes 3 are provided. Since the convex portions 13 are provided in correspondence with the central portions of 3c, when a voltage is applied between the electrodes 3 and 20, each of the square electrode portions 3a, 3b and 3c of the pixel electrode 3 corresponding to the square electrode portions 3a, 3b and 3c. The liquid crystal molecules 27a in the region are respectively induced by the potential distribution in the vicinity of the convex portion 13 and the behavior of the liquid crystal molecules in the peripheral portion of each pixel portion, and as shown in FIG. 5 and FIG. From the peripheral edge of the Oriented fallen to a constant.

  That is, in the liquid crystal display element, since the pixel electrode 3 is formed so as to cover the convex portion 13, each square electrode portion 3 a of the pixel electrode 3 is applied by applying a voltage between the electrodes 3 and 20. , 3b, 3c, the electric field generated in each region corresponds to the potential of the portion corresponding to the convex portion 13 as shown in the equipotential line e in FIG. The electric field is biased toward the front substrate 2 side.

  Therefore, the liquid crystal molecules 27a are applied to the periphery of the region along the equipotential line e for each region corresponding to each of the square electrode portions 3a, 3b, 3c of the pixel electrode 3 by applying the voltage. From the portion toward the center portion, the portion corresponding to the center of the convex portion 13 is stably tilted with the portion in the tilting direction as the center.

  As described above, the liquid crystal display element is disposed on the inner surface of the substrate 1 after the plurality of pixel electrodes 3 are provided in the pair of substrates 1 and 2 so as to correspond to the respective central portions of the plurality of pixel electrodes 3. Since the plurality of convex portions 13 projecting from the inner surface of the substrate corresponding to other regions of the pixel electrode 3 are provided, the negative dielectric anisotropy enclosed in the gap between the pair of substrates 1 and 2 is reduced. The liquid crystal molecules 27a of the liquid crystal layer 27 are provided between the electrodes 3 and 20 for each of the plurality of pixels 28 each having a region in which the plurality of pixel electrodes 3 and the counter electrode 20 provided on the inner surface of the front substrate 2 face each other. By applying a voltage to the pixel 28, it is possible to stably tilt and orient the pixel 28 from the edge toward the center, and display an image of good quality without a feeling of roughness.

  In addition, since the pixel electrode 3 is formed so as to cover the convex portion 13 in the liquid crystal display element, the liquid crystal molecules 27a are moved from the edge of the pixel 28 toward the center by applying the voltage. Furthermore, it is possible to stably tilt and align and display a higher quality image.

  Further, in the liquid crystal display element, the plurality of pixel electrodes 3 are each formed in an elongated rectangular shape, and the rectangular shapes are arranged in a plurality of substantially square electrode portions 3a, 3b, 3c arranged in the longitudinal direction thereof. The liquid crystal is formed by the conductive film provided with the slits 4 to be divided, and the convex portion 13 is provided in correspondence with the central portions of the plurality of electrode portions 3a, 3b, 3c of the pixel electrode 3, respectively. By applying the voltage, the molecules 27a can be stably tilted and oriented from the peripheral portion toward the center portion for each of the regions corresponding to the plurality of electrode portions 3a, 3b, 3c of the pixel electrode 3. Further, even when the aspect ratio of the pixel electrode is increased in order to increase the pixel definition, a stable alignment state can be obtained.

  Further, in the liquid crystal display element, the convex portion 13 is formed on the same film as all of the plurality of films 6, 7, 8, 9, 10, 11 D and 11 S, 12 constituting the TFT 5, that is, the gate electrode 6 and The lower metal film 6a made of the same metal film as the scanning line 14, the gate insulating film 7, the lower semiconductor made of the same semiconductor film or insulating film as the i-type semiconductor film 8, the blocking insulating film 9 and the n-type semiconductor film 10. The film 8a, the intermediate insulating film 9a, the upper semiconductor film 10a, the upper metal film 11a made of the same metal film as the drain electrode 11D and the source electrode 11S, and the upper insulating film 12a made of the same insulating film as the overcoat insulating film 12 Therefore, the protrusion 13 is formed without increasing the manufacturing cost of the liquid crystal display element by using the formation process of the TFT 5. Door can be.

  In the above embodiment, the convex portion 13 is formed by a laminated film of the same films 6a, 7, 8a, 9a, 10a, 11a, and 12a as all of the plurality of films constituting the TFT 5. The protrusion 13 is the same film as a part of the plurality of films constituting the TFT 5, for example, the lower metal film 6a, the gate insulating film 7, the upper metal film 11a, and the upper insulating film. You may form by a laminated film with 12a.

(Second Embodiment)
7 and 8 show a second embodiment of the present invention. FIG. 7 is a plan view of a part of one substrate (rear substrate) of the liquid crystal display element, and FIG. 8 shows the liquid crystal display element of this embodiment. It is the top view which showed typically the orientation state of the liquid crystal molecule when a voltage is applied between the electrodes in one pixel. In FIG. 7, 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, each of the plurality of pixel electrodes 3 is formed of a transparent conductive film formed in an elongated rectangular shape, and the capacitor electrode 16 that forms the compensation capacitor 19 is provided as a TFT connection portion of the pixel electrode 3. The pixel electrode 3 is provided in correspondence with the peripheral edge, and on the inner surface of the substrate 1 on which the plurality of pixel electrodes 3 are provided, corresponding to the center of each of the plurality of pixel electrodes 3, and in the longitudinal direction of the pixel electrode 3. Are provided with an elongated convex portion 13a extending over substantially the entire length, and the other configuration and the cross-sectional structure of the convex portion 13a are the same as those of the first embodiment.

  In this liquid crystal display element, the convex portion 13a is provided over substantially the entire length in the longitudinal direction of the pixel electrode 3 so as to correspond to the central portion of the pixel electrode 3 in the narrow direction. By applying a voltage between the electrodes 3 and 20, as shown in FIG. 8, the pixel 28 is stably tilted and oriented from the edge on both sides in the longitudinal direction toward the center, and a good quality image without a feeling of roughness. Can be displayed. Further, even when the aspect ratio of the pixel electrode is increased in order to increase the pixel definition, a stable alignment state can be obtained.

(Third embodiment)
FIG. 9 is a sectional view of a part of one substrate (rear substrate) of a liquid crystal display device according to a third embodiment of the present invention. In FIG. 9, parts corresponding to those of the first embodiment described above are given the same reference numerals, and explanations of the same parts are omitted.

  In this embodiment, in the liquid crystal display element of the first embodiment, the convex portion 13 is formed by using all the films 6, 7, 8, 9, 10, 11D and 11S, 12 of the plurality of films constituting the TFT 5 or A laminated film of the same film as a part (in the figure, a laminated film of the same films 6 a, 7, 8 a, 9 a, 10 a, 11 a, 12 a as all of the plurality of films constituting the TFT 5) and a capacitance for forming the compensation capacitor 19 The electrode 16 is formed of a laminated film of a conductive film 16a made of the same transparent conductive film. According to this embodiment, the protrusion 13 is formed by using the process of forming the TFT 5 and the compensation capacitor 19. The liquid crystal display element can be formed without increasing the manufacturing cost.

  In this embodiment, a conductive film 16a made of the same transparent conductive film as the capacitor electrode 16 is formed on the plate surface of the rear substrate 1, and the same metal as the gate electrode 6 and the scanning line 14 of the TFT 5 is formed thereon. A lower metal film 6a made of a film is formed. As in the modification of the third embodiment shown in FIG. 10, the lower metal film 6a is formed on the plate surface of the rear substrate 1, and the upper metal film 6a is formed thereon. Alternatively, the conductive film 16a may be formed.

  Further, the third embodiment and its modification can be applied to the convex portion 13a of the second embodiment described above.

(Fourth embodiment)
FIG. 11 is a sectional view of a part of one substrate (rear substrate) of a liquid crystal display device according to the fourth embodiment of the present invention. In FIG. 11, parts corresponding to those of the first embodiment described above are given the same reference numerals, and explanations of the same parts are omitted.

  In the liquid crystal display element of this embodiment, a plurality of TFTs 5 are provided between the drain electrode 11D and the source electrode 11S and the overcoat insulating film 12, and a transparent protective insulating film 18 is provided over the signal line 15 from the TFT portion. A capacitor electrode 16 made of a transparent conductive film such as an ITO film is formed on the side edge of the protective insulating film 18 that covers the signal line 15, and the overcoat insulating film 12 is connected to the signal line from the TFT portion. 15 is formed to have a width that covers substantially the entire protective insulating film 18, and the pixel electrode 3 is formed so that its edge overlaps the edge of the overcoat insulating film 12. A compensation capacitor 19 having the overcoat insulating film 12 as a dielectric layer is formed between the edge of the pixel electrode 3 and in this embodiment, the capacitor electrode 16 is connected to the image electrode. The outer peripheral edge portion overhangs outwardly of the electrode 3, and its over connecting portion of the entire circumference and adjacent capacitor electrodes 16 and 16, two-layer membrane electrode formed by laminating a low-resistance film 17 made of a metal film.

  In FIG. 11, the low resistance film 17 is formed on the protective insulating film 18 and the capacitor electrode 16 is formed on the low resistance film 17. On the contrary, the capacitor electrode 16 is formed on the protective insulating film 18. The capacitor electrode 16 may be formed, and the low resistance film 17 may be formed thereon.

  In this embodiment, the TFT 5 is formed on the inner surface of the substrate 1 on which the plurality of pixel electrodes 3 are provided, corresponding to the center portions of the plurality of square electrode portions 3a, 3b, 3c of the pixel electrode 3, respectively. The same film as all of the plurality of films constituting the gate electrode, that is, the lower metal film 6a made of the same metal film as the gate electrode 6 and the scanning line 14, the gate insulating film 7, the i-type semiconductor film 8, the blocking insulating film 9 and a lower semiconductor film 8a made of the same semiconductor film or insulating film as the n-type semiconductor film 10, an intermediate insulating film 9a, an upper semiconductor film 10a, an upper metal film 11a made of the same metal film as the drain electrode 11D and the source electrode 11S, An upper insulating film 12a made of the same insulating film as the overcoat insulating film 12, a second intermediate insulating film 18a made of the same insulating film as the protective insulating film 18, and the overcoat film Each film of the upper insulating film 12a made of the same insulating film as the insulating film 12 and the same film as the capacitor electrode 16 on which the low resistance film 17 is laminated, that is, an intermediate metal film made of the same metal film as the low resistance film 17 17a and a convex part formed of a laminated film of the conductive film 16a made of the same transparent conductive film as the capacitor electrode 16 and having a substantially truncated cone shape (a circumferential surface having a stepped truncated cone shape). 13 is provided, and the pixel electrode 3 is formed thereon.

  In the liquid crystal display element of this embodiment, the convex portion 13 is made up of the same films 6 a, 7, 8 a, 9 a, 10 a, 11 a, 17 a, 12 a as the plurality of films constituting the TFT 5, and the low resistance film 17. Since the convex portion 13 made of a laminated film of the same film 17 a and 16 a as the laminated capacitive electrode 16 is provided, the convex portion 13 is formed into a liquid crystal display by using the formation process of the TFT 5 and the compensation capacitance 19. It can be formed without increasing the manufacturing cost of the element.

  In this embodiment, the convex portion 13 is formed by laminating the same films 6 a, 7, 8 a, 9 a, 10 a, 11 a, 17 a, 12 a and the low resistance film 17 as the plurality of films constituting the TFT 5. The convex portion 13 is formed of the same film as a part of the plurality of films constituting the TFT 5, for example, the lower part. Capacitance in which the metal film 6a, the gate insulating film 7, the upper metal film 11a, the second intermediate insulating film 18a, the upper insulating film 12a, and the low resistance film 17 are stacked. You may form by the laminated film of the film | membranes 17a and 16a same as the electrode 16. FIG.

  Moreover, the formation structure of the compensation capacitor 19 and the convex portion 13 of this embodiment can also be applied to the second embodiment described above.

(Fifth embodiment)
12 to 15 show a fifth embodiment of the present invention. FIG. 1 is a plan view of a part of one substrate (rear substrate) of the liquid crystal display element, and FIG. 13 is a plan view of the liquid crystal display element in FIG. It is an expanded sectional view which follows a XIII-XIII line. In FIG. 12 and FIG. 13, the same reference numerals are given to the components corresponding to the first embodiment described above, and the description of the same components is omitted.

  In the liquid crystal display element of this embodiment, the plurality of pixel electrodes 3 are provided on the inner surface of the substrate 1 so as to correspond to the central portions of the plurality of square electrode portions 3a, 3b, 3c of the pixel electrode 3, respectively. It is formed in a shape having a predetermined ratio with respect to the area of each square electrode portion 3a, 3b, 3c of the pixel 28, for example, 25 to 50% of the area of the square electrode portions 3a, 3b, 3c. A plurality of convex portions 13 are provided, and light incident on a portion corresponding to the convex portion 13 from the observation side (the outer surface side of the front substrate 2) is reflected on the inner surface of the rear substrate 1 and emitted to the observation side. The reflective display unit 28a and a plurality of transmissive display units 28b other than the reflective display unit 28a that transmit the light incident from the side opposite to the observation side (the outer surface side of the rear substrate 1) and emit the light to the observation side. First and second for forming every pixel 28 It is those in which a reflection film 23 and 24, other configurations are the same as those in the first embodiment.

  In this embodiment, the convex portion 13 is made of the same laminated film as that of the first embodiment, and is substantially formed in a truncated cone shape (a circumferential surface is a stepped cone shape). .

In this embodiment, the convex portion 13 is formed of a laminated film of the same film as all of the plurality of films constituting the TFT 5, and a part of the plurality of films constituting the TFT 5 A film for forming the convex portion 13 made of the same film, for example, two films of the drain electrode 11D and the source electrode 11S and the overcoat insulating film 12 among the plurality of films constituting the TFT 5, and the convex portion 13 The two films of the upper metal film 11a made of the same metal film as the drain electrode 11D and the source electrode 11S and the upper insulating film 12a made of the same insulating film as the overcoat insulating film 12 are formed as the reflection film. formed in a substantially film thickness becomes 1/2 of the liquid crystal layer thickness d ₂ of the liquid crystal layer thickness d ₁ of the display unit 28a is the transmissive display portion 14b, the light incident from the observation side reciprocates through the liquid crystal layer 27 The product [Delta] nd ₁ transmitted to the liquid crystal of the birefringence anisotropy Δn of the reflective display unit 28a for emitting to the observation side of the liquid crystal layer thickness d _1, substantially one of the product [Delta] nd ₂ of the transmissive display portion 14b / 2 is set.

  In this embodiment, the first and second reflective films 23 and 24 are made of the same metal film as the gate electrode 6 and the scanning line 14 of the TFT 5 in the laminated film forming the convex portion 13. The lower metal film 6a and the upper metal film 11a made of the same metal film as the drain electrode 11D and the source electrode 11S are formed.

  Of these reflective films 23 and 24, the first reflective film 23 made of the lower metal film 6a is formed into a circular film having a diameter corresponding to the diameter of the base of the truncated conical convex portion 13, The second reflective film 24 made of the upper metal film 11a is formed in a circular film having a smaller diameter than the first reflective film 23, and the second reflective film 24 is incident from the observation side. Of the light transmitted through the liquid crystal layer 27, the light incident on the second reflection film 24 is reflected to the observation side, and the first reflection film 23 is incident from the observation side and is incident on the liquid crystal layer 27. Of the light transmitted through the second reflection film 24 and incident on the outer peripheral portion of the first reflection film 23 (the portion protruding around the second reflection film 24) through the periphery of the second reflection film 24 Reflect to the side.

  That is, among the plurality of regions respectively corresponding to the square electrode portions 3a, 3b, and 3c of the pixel electrode 3 of the pixel 28, the circular region corresponding to the convex portion 13 at the center of these regions. A reflective display portion 28a is formed, and the transmissive display portion 28b is formed by a region around the reflective display portion 28a of the plurality of regions.

  This liquid crystal display element includes a plurality of pixel electrodes 3, TFTs 5, scanning lines 14, signal lines 15, and a plurality of convex portions 13, and the inner surface of the rear substrate 1 on the opposite side of the pair of substrates 1 and 2 from the observation side. The convex portion 13 is formed in a shape having an area with a predetermined ratio with respect to the area of the pixel 28, and is incident on the rear substrate 1 from the observation side to a portion corresponding to the convex portion 13 The reflective display unit 28a that reflects the emitted light and emits it to the observation side, and the transmissive display unit 28b other than the reflective display unit 28a that transmits the light incident from the opposite side to the observation side and emits it to the observation side Are provided for each of the plurality of pixels 28, so that a reflective display that uses external light, which is light in the usage environment of the liquid crystal display element, and an observation side of the liquid crystal display element, Is from a surface light source (not shown) placed on the opposite side It can be performed transmissive display and utilize.

  Further, in this embodiment, the reflective films 23 and 24 are formed of the lower metal film 6a made of the same metal film as the gate electrode 6 and the scanning line 14 of the TFT 5 in the laminated film forming the convex portion 13, and Since the drain electrode 11D and the upper metal film 11a made of the same metal film as the source electrode 11S are formed, the reflective films 23 and 24 are formed using the TFT 5 formation process, thereby reducing the manufacturing cost of the liquid crystal display element. It can be formed without increasing.

  FIG. 14 is a cross-sectional view schematically showing the alignment state of liquid crystal molecules when no voltage is applied between the electrodes 3 and 20 in one pixel 28 of the liquid crystal display element of this embodiment, and FIG. 3 is a cross-sectional view schematically showing an alignment state of liquid crystal molecules when a voltage is applied between the electrodes 3 and 20 in one pixel 28. FIG. In FIGS. 14 and 15, the convex portion 13 is simplified.

  As shown in FIG. 14, when no voltage is applied between the electrodes 3 and 20, the liquid crystal molecules 27a of the liquid crystal layer 27 are formed on the vertical alignment films 25 and 26 provided on the inner surfaces of the pair of substrates 1 and 2, respectively. Due to the vertical alignment property, the substrate is oriented substantially perpendicularly to the surfaces of the substrates 1 and 2 in a region other than the portion corresponding to the convex portion 13, and the portion on the rear substrate 1 side in the portion corresponding to the convex portion 13. The liquid crystal molecules 27a in the vicinity of the convex portion 13 are aligned with the molecular major axis in a direction substantially perpendicular to the top and peripheral surfaces of the convex portion 13, and the liquid crystal molecules 27a in the vicinity of the front substrate 2 are It is oriented in a state of being oriented substantially perpendicular to the front substrate 2 surface.

  When a voltage is applied between the electrodes 3 and 20, the liquid crystal molecules 27 a in the respective regions corresponding to the respective square electrode portions 3 a, 3 b and 3 c of the pixel electrode 3 are respectively distributed in potential in the vicinity of the convex portion 13. Induced by the behavior of the liquid crystal molecules at the periphery of each pixel portion, as shown in FIG. 15, each region is stably tilted and oriented from the peripheral portion to the central portion of the region.

  That is, in this liquid crystal display element, since the pixel electrode 3 is formed so as to cover the convex portion 13, each square electrode portion 3 a of the pixel electrode 3 is applied by applying a voltage between the electrodes 3 and 20. , 3b and 3c, the electric field generated in each region corresponds to the potential of the portion corresponding to the convex portion 13 as shown in the equipotential line e in FIG. The electric field is biased toward the front substrate 2 side.

  Therefore, the liquid crystal molecules 27a are applied to the periphery of the region along the equipotential line e for each region corresponding to each of the square electrode portions 3a, 3b, 3c of the pixel electrode 3 by applying the voltage. From the portion toward the center portion, the portion corresponding to the center of the convex portion 13 is stably tilted with the portion in the tilting direction as the center.

  Therefore, in this liquid crystal display element, the liquid crystal molecules 27a are stably tilted from the edge of the pixel 28 toward the center by applying a voltage between the electrodes 3 and 20 for each of the plurality of pixels 28. It is possible to display an image with a good quality without a feeling of roughness in both the reflective display and the display.

  In addition, since the pixel electrode 3 is formed so as to cover the convex portion 13 in the liquid crystal display element, the liquid crystal molecules 27a are moved from the edge of the pixel 28 toward the center by applying the voltage. Furthermore, it is possible to stably tilt and align and display a higher quality image.

  In this embodiment, the convex portion 13 is formed of a laminated film having the same film as all of the plurality of films constituting the TFT 5, but the convex portion 13 is formed of FIGS. 9, 10, and 11. You may form by the same laminated film as the Example shown in.

  The convex portion 13 may be formed of a laminated film that is the same film as a part of the plurality of films constituting the TFT 5, and in this case, the convex portion 13 constitutes the TFT 5. A stack including at least one of a lower metal film 6a made of the same metal film as the gate electrode 6 and the scanning line 14 and an upper metal film 11a made of the same metal film as the drain electrode 11D and the source electrode 11S. It is formed by a film.

(Sixth embodiment)
FIG. 16 is a plan view of a part of one substrate (rear substrate) of a liquid crystal display device according to the sixth embodiment of the present invention. The liquid crystal display device of this embodiment is a pixel in the second embodiment described above. The elongated convex portion 13a extending over substantially the entire length in the longitudinal direction of the electrode 3 is formed into a shape having an area with a predetermined ratio (for example, 25 to 50%) with respect to the area of the pixel 28, and the convex portion 13a is formed. As in the convex portion 13 of the fifth embodiment described above, the first and second for forming the reflective display portion 28a and the transmissive display portion 28b other than the reflective display portion 28a for each of the plurality of pixels 28. In this structure, at least one of the reflective films 23 and 24 is provided.

  In the fifth and sixth embodiments, the reflection films 23 and 24 are formed of at least one metal film among the laminated films forming the protrusions 13 and 13a. 13 and 13a may be formed of a plurality of transparent films, and a reflective film for forming the reflective display portion 28a and the transmissive display portion 28b for each of the plurality of pixels 28 may be provided on the outer surface of the rear substrate 1. .

  DESCRIPTION OF SYMBOLS 2 ... Substrate, 3 ... Pixel electrode, 3a, 3b, 3c ... Electrode part, 4 ... Slit, 5 ... TFT, 6 ... Gate electrode, 7 ... Gate insulating film, 8 ... i-type semiconductor film, 9 ... Blocking insulating film, DESCRIPTION OF SYMBOLS 10 ... n-type semiconductor film, 11D ... Drain electrode, 11S ... Source electrode, 12 ... Overcoat insulating film, 16 ... Capacitance electrode, 17 ... Low resistance film, 13, 13a ... Convex part, 6a ... Lower metal film, 8a ... Lower semiconductor film, 9a ... intermediate insulating film, 10a ... upper semiconductor film, 11a ... upper metal film, 12a ... upper insulating film, 16a ... conductive film, 17a ... intermediate metal film, 18a ... second intermediate insulating film, 19 ... Compensation capacitance, 20 ... counter electrode, 21 ... light shielding film, 22R, 22G, 22B ... color filter, 23, 24 ... reflection film, 25, 26 ... vertical alignment film, 27 ... liquid crystal layer, 27a ... liquid crystal molecule, 28 ... pixel , 28a ... reflection display section 28b ... the transmissive display portion.

Claims (11)

The first substrate and the second substrate are arranged to face each other through a liquid crystal layer made of a liquid crystal having a negative dielectric anisotropy,
A liquid crystal display element in which a pixel electrode is divided into a plurality of electrode portions for each display pixel, and the pixel electrode is connected to a thin film transistor for each display pixel ,
It is arranged at a position corresponding to the center of each electrode part, and has a convex part formed at a height lower than the thickness of the liquid crystal layer,
The convex portion is
A gate insulating film covering the gate of the thin film transistor;
A plurality of insulating layers formed on the gate insulating film so as to have a shape smaller than the electrode portion and gradually decreasing from the lower layer toward the upper layer;
A semiconductor film or a metal film, which is disposed between the insulating layers adjacent to each other above and below and formed in a shape larger than the insulating film in contact with the upper layer side;
A liquid crystal display element comprising:   The liquid crystal display element according to claim 1, wherein the semiconductor film or the metal film is formed in a shape in which an end face of an insulating film in contact with a lower layer side is exposed. 3. The liquid crystal display element according to claim 1, wherein the semiconductor film or the metal film is formed of the same material as any of the films constituting the thin film transistor at the same time. Each of the insulating layer and the semiconductor film or the metal film in the convex portions, the liquid crystal display device according to any one of claims 1 to 3, respectively, characterized in that it is formed in a circular shape. The liquid crystal layer is arranged such that liquid crystal molecules are aligned perpendicular to the substrate surfaces when no voltage is applied between the pixel electrode and the counter electrode disposed to face the pixel electrode. the liquid crystal display device according to any one of claims 1 to 4, characterized in that it is set to. Capacitor electrodes which are set to the counter electrode and the same potential, according to claim 5, characterized in that it is arranged between two of said protrusions adjacent to each other in and the pixel electrode in the lower layer side of the pixel electrode Liquid crystal display element. The liquid crystal display element according to claim 6 , wherein the capacitor electrode is disposed so as to close a slit interposed between two adjacent electrode portions in the pixel electrode. The liquid crystal display device according to any one of claims 1 to 7, wherein the electrode portions are electrically connected by a predetermined connecting portion in the pixel electrode. The first substrate and the second substrate are arranged to face each other through a liquid crystal layer made of a liquid crystal having a negative dielectric anisotropy,
A liquid crystal display element formed such that a pixel electrode having a plurality of electrode portions for dividing the alignment direction of the liquid crystal layer is connected to a thin film transistor for each display pixel,
It is arranged at a position corresponding to the center of each electrode part, and has a convex part formed at a height lower than the thickness of the liquid crystal layer,
The convex portion is
A gate insulating film covering the gate of the thin film transistor;
A plurality of insulating layers formed on the gate insulating film so as to have a shape smaller than the electrode portion and gradually decreasing from the lower layer toward the upper layer;
A semiconductor film or a metal film, which is disposed between the insulating layers adjacent to each other above and below and formed in a shape larger than the insulating film in contact with the upper layer side;
A liquid crystal display element comprising: The first substrate and the second substrate are arranged to face each other through a liquid crystal layer made of a liquid crystal having a negative dielectric anisotropy,
A liquid crystal display element formed such that a pixel electrode provided with a plurality of slits for dividing the alignment direction of the liquid crystal layer is connected to a thin film transistor for each display pixel,
It is disposed at a position corresponding to the center between two adjacent slits, and has a convex portion formed at a height lower than the thickness of the liquid crystal layer,
The convex portion is
A gate insulating film covering the gate of the thin film transistor;
A plurality of insulating layers formed on the gate insulating film so as to have a shape smaller than the pixel electrode and gradually decreasing from the lower layer toward the upper layer;
A semiconductor film or a metal film, which is disposed between the insulating layers adjacent to each other above and below and formed in a shape larger than the insulating film in contact with the upper layer side;
A liquid crystal display element comprising: The first substrate and the second substrate are arranged to face each other through a liquid crystal layer made of a liquid crystal having a negative dielectric anisotropy,
A pixel electrode is connected to the thin film transistor for each display pixel,
A liquid crystal display device in which the convex portion of the linear shape for dividing the orientation direction of the liquid crystal layer is formed on the display each pixel in a region corresponding to the pixel electrode,
The convex portion is
A gate insulating film covering the gate of the thin film transistor;
A plurality of insulating layers formed on the gate insulating film so as to have a shape smaller than the pixel electrode and gradually decreasing from the lower layer toward the upper layer;
A semiconductor film or a metal film that is disposed between the insulating layers adjacent to each other above and below and formed in a shape larger than the insulating film in contact with the upper layer side, and
A liquid crystal display element having a height lower than the thickness of the liquid crystal layer.

Images