KR100327928B1 - Liquid crystal display device - Google Patents

Abstract

The liquid crystal display of the present invention includes a gate signal line, a source signal line intersecting the gate signal line, an interlayer insulating film formed on the gate signal line and the source signal line, and a pixel electrode formed on the interlayer insulating film, The first pixel electrode and the second pixel electrode which are adjacent to each other on both sides of the line are partially overlapped with the gate signal line sandwiched by the first pixel electrode and the second pixel electrode and the overlapping of the first pixel electrode and the gate signal line The width is different from the overlap width of the second pixel electrode and the gate signal line.

Description

[0001] LIQUID CRYSTAL DISPLAY DEVICE [0002]

The present invention relates to a liquid crystal display device used in a display portion such as a computer and an OA device. More particularly, the present invention relates to a liquid crystal display device having excellent display characteristics and high aperture ratio.

Conventionally, a liquid crystal display device using an active matrix substrate is known as a display device of a computer and an OA device. An example of a liquid crystal display device using an active matrix substrate is shown in Fig. The active matrix substrate in this example has a thin film transistor (hereinafter referred to as a TFT) as a switching element.

Referring to Fig. 26, a TFT 106 and a pixel capacitor 108 are formed in a matrix on a substrate made of glass or the like. The gate electrode of each TFT 106 is connected to the corresponding gate signal line 104 so that the TFT 106 is switched on and off in response to a signal input to the gate electrode through the gate signal line 104. The source electrode of the TFT 106 is connected to the corresponding source signal line 102, and a video signal is input to the TFT 106. [ The drain electrode of the TFT 106 is connected to one terminal of the corresponding pixel capacitor 108 with the pixel electrode. The other terminal of the pixel capacitor 108 is connected to the corresponding pixel capacitor line 110 and also to the counter electrode provided on the substrate facing the active matrix substrate.

FIG. 27 is a plan view of the active matrix substrate having such a structure, FIG. 28 is a cross-sectional view taken along line A-A 'of FIG. 27, and FIG. 29 is a cross-sectional view taken along line B-B' of FIG. 27.

27 and 28, each pixel of the liquid crystal display device includes a TFT 106 (see FIG. 26), an elongated drain electrode 125, a storage capacitor electrode 126, and a pixel electrode 140 . 29, for each pixel, a gate signal line 104, a gate insulating film 103, a semiconductor layer 134, a channel protective layer 128, a gate electrode, ^The pixel electrode 140 made of the ⁺ -Si layer 130 and the ITO (indium tin oxide) film 132, the source signal line 102 made of the metal layer, the interlayer insulating film 136, Is formed on the transparent insulating substrate 120 to form an active matrix substrate. The pixel electrode 140 is connected to the drain electrode of the TFT 106 through the connection hole 142 (see FIG. 28) formed through the interlayer insulating film 136. 28 and 29 also show a substrate 122 provided to face an active matrix substrate, and a liquid crystal layer 112 is provided between these substrates.

In the active matrix substrate having the above structure, an interlayer insulating film 136 is formed between the gate signal line 104 and the source signal line 102 and the pixel electrode 140. As a result, the periphery of the pixel electrode 104 overlaps with the signal lines 102 and 104. As a result, a liquid crystal display device having a high aperture ratio can be obtained. Moreover, the overlapped pixel electrode 104 can shield the electric field generated due to the electric potential at the signal lines, effectively restraining the alignment defect of the liquid crystal molecules.

28 and 29, a color layer 146 representing red, green, or blue constituting the light shielding layer 144 and the color filter is formed on the substrate 122 opposed to the active matrix substrate, A liquid crystal layer 112 is provided between these substrates. On the color filter, the counter electrode 148 and the alignment film 150 are formed in the order described. Another alignment film 150 is formed on the surface of the active matrix substrate in contact with the liquid crystal layer 112.

Fig. 30A is an enlarged plan view of a part of Fig. 27, in which the gate signal line 104 and the source signal line 102 are crossed with each other. 30B is a cross-sectional view taken along the line C-C 'in FIG. 30A, showing overlapping portions of the source signal line 102 and the pixel electrode 140. FIG.

Referring to FIG. 30A, vertically adjacent pixel electrodes 140 overlap with corresponding gate signal lines 104 by overlap widths dg1 and dg2, while horizontally adjacent pixel electrodes 140 correspond to corresponding Overlapping with the source signal line 102 by overlap widths ds1 and ds2. These overlapping widths generally correspond to the processing precision of the gate signal line 104 and the source signal line 102 serving as the light shielding film and the processing accuracy of the gate signal line 104 and the overlapping precision of the source signal line 102 and the pixel electrode 140 And the processing precision of the pixel electrode 140 are taken into account. Conventionally, the pixel electrode 140 overlaps the gate signal line 104 and the source signal line 102 such that the overlap widths dg1 and dg2 are equal to each other and the overlap widths ds1 and ds2 are equal to each other.

There is no problem as long as the liquid crystal display device in which the pixel electrode is overlapped with the signal line as described above is driven by the frame inversion driving method. However, when such a liquid crystal display device is driven by the gate line inversion driving method or the dot inversion driving method, the following problems arise. That is, referring to FIG. 30B, the alignment of the liquid crystal molecules 152a is poor due to the electric field generated between the adjacent pixel electrodes, and a reverse tilt region having the liquid crystal molecules 152b having the reverse pretilt angle is generated , that is, D ₁ and the alignment direction of the alignment the liquid crystal molecules (152a) of the liquid crystal molecules (152b) (see FIG. 30a) is the opposite direction. The generation of light by this reverse tilt zone causes the display characteristics of the manufactured liquid crystal display device to be extremely reduced.

A method of increasing the overlap width between the gate signal line and the source signal line and the pixel electrode is known in order to prevent light leakage of the liquid crystal display device due to orientation defects of the liquid crystal molecules. However, when the overlap width is increased, the occupancy rate of the light shielding portion is increased in the liquid crystal display device, which causes another problem that the aperture ratio is decreased.

Further, a liquid crystal display device is also known in which each pixel is divided into two portions having different alignment directions D ₁ and D ₂ of different liquid crystal molecules as shown in Figs. 31A to 31C. 31A shows a plan view of a part of a liquid crystal display device in which a gate signal line 104 and a source signal line 102 intersect with each other. 31B is a cross-sectional view taken along line C-C 'of FIG. 31A, and FIG. 31C is a cross-sectional view taken along a line D-D' of FIG. 31A.

In this liquid crystal display device, the pixel electrodes are overlapped with the signal lines so that the overlap widths dg1 and dg2 are equal to each other and overlap widths ds1 and ds2 are equal to each other, as shown in Fig. 31A. This is not a problem when the liquid crystal display device is driven by the flip-flip method. However, as in the case described above, the following problems arise when driving by the gate line inversion driving method, the source line driving method, or the dot line driving method. That is, the orientation of the liquid crystal molecules 152a becomes poor due to the electric field generated between adjacent pixel electrodes, and as shown in Figs. 31B and 31C, the reverse tilt region having the liquid crystal molecules 152b of the reverse pretilt angle Resulting in light leakage, and the display characteristics of the manufactured liquid crystal display device are extremely deteriorated.

In this case, as in the above case, the overlap width of the pixel line, the gate signal line, and the source signal line can be increased to prevent light leakage due to the orientation defect of the liquid crystal molecules. However, this causes another problem that the occupancy rate of the light-shielding portion is increased and the aperture ratio is lowered in the liquid crystal display device.

Referring again to Figures 27 and 28, a reverse tilt zone is also generated in each of the connection holes 142, or in the vicinity thereof, as indicated by reference numeral 154. This reverse tilt zone tends to occur particularly when the inner wall angle of the connection hole 142 is greater than 45. with respect to the substrate surface. The light leakage may also occur when the liquid crystal layer 112 is switched from the light-transmitting state to the light-shielding state.

Shielding material is used for the connection hole 142 or the peripheral area thereof to the storage capacitor electrode 126 in which the connection hole 142 is formed at the upper part thereof as a method for preventing light leakage at the connection hole or its peripheral part Thereby shielding the light from the light. However, it is necessary to increase the size of the storage capacitor electrode 126 in order to achieve complete shielding. This causes a problem of reducing the aperture ratio of the liquid crystal display device manufactured by actually reducing the display area of each pixel.

Japanese Patent Laid-Open No. 5-249494 discloses a method for suppressing the generation of a reverse tilt zone in an active matrix type liquid crystal display device. According to the disclosed method, the inclination step angle between the pixel electrode and the gate and source signal lines with respect to the substrate surface is set to 60 or less so that a disclination line is generated on the display screen .

However, according to the method described above, satisfactory results can not be obtained when the step difference between the pixel electrode and the gate and source signal lines exceeds 2 탆. 28, when the step difference (corresponding to the thickness of the interlayer insulating film 136) exceeds 2 mu m, a reverse tilt region is formed at or around the connection hole 142 . Therefore, in order to apply the above method to the connection hole 142, the thickness of the interlayer insulating film 136 should be 2 占 퐉 or less.

On the other hand, the interlayer insulating film 136 needs to be thick enough to have a flat surface necessary for planarizing the alignment film 150 to be formed on the interlayer insulating film 136 in contact with the liquid crystal layer 112. Therefore, it is practically difficult to set the thickness of the interlayer insulating film 136 to 2 mu m or less. Therefore, this method can not be applied to a region having a connection hole.

The liquid crystal display of the present invention comprises a gate signal, a source signal line intersecting the gate signal line, an interlayer insulating film formed on the gate signal line and the source signal line, and a pixel electrode formed on the interlayer insulating film, The overlapping widths of the first pixel electrode and the gate signal line are partially overlapped with the gate signal line sandwiched by the first pixel electrode and the second pixel electrode, Which is different from the overlap width of the pixel electrode and the gate signal line.

In one embodiment of the present invention, the first pixel electrode is located downstream of the pretilt angle direction of the liquid crystal molecule with respect to the gate signal line, the second pixel electrode is located upstream of the pretilt angle direction of the liquid crystal molecule, The overlap width of one pixel electrode and the gate signal line is larger than the overlap width of the second pixel electrode and the gate signal line.

In another embodiment of the present invention, the liquid crystal display is driven by the gate line inversion driving method.

Alternatively, the liquid crystal display of the present invention includes a gate signal, a source signal line intersecting the gate signal line, an interlayer insulating film formed on the gate signal line and the source signal line, and a pixel electrode formed on the interlayer insulating film, The third pixel electrode and the fourth pixel electrode which are not in contact with each other partially overlap with the source signal line sandwiched by the third pixel electrode and the fourth pixel electrode and the overlap width of the third pixel electrode and the source signal line is And the overlap width of the fourth pixel electrode and the source signal line is different.

In one embodiment of the present invention, the third pixel electrode is located downstream of the pretilt angular direction of the liquid crystal molecules with respect to the source signal line, the fourth pixel electrode is located upstream of the pretilt angular direction of the liquid crystal molecules, The overlap width of the three pixel electrodes and the source signal line is larger than the overlap width of the fourth pixel electrode and the source signal line.

In another embodiment of the present invention, the liquid crystal display is driven by the source line inversion driving method.

Alternatively, the liquid crystal display of the present invention comprises a gate signal, a source signal line intersecting the gate signal line, an interlayer insulating film formed on the gate signal line and the source signal line, and a pixel electrode formed on the interlayer insulating film, The first pixel electrode and the second pixel electrode which are adjacent to each other on both sides are partially overlapped with the gate signal line sandwiched by the first pixel electrode and the second pixel electrode and the overlap width of the first pixel electrode and the gate signal line is The third pixel electrode and the fourth pixel electrode which are adjacent to each other on both sides of the source signal line are different from the overlap width of the second pixel electrode and the gate signal line, and the source signal line, sandwiched by the third pixel electrode and the fourth pixel electrode, And the overlap width of the third pixel electrode and the source signal line is partially overlapped with that of the fourth pixel electrode and the source signal line Wrap width is different.

In one embodiment of the present invention, the first pixel electrode is located downstream of the pretilt angle direction of the liquid crystal molecule with respect to the gate signal line, the second pixel electrode is located upstream of the pretilt angle direction of the liquid crystal molecule, The overlap width of the one pixel electrode and the gate signal line is larger than the overlap width of the second pixel electrode and the gate signal line and the third pixel electrode is located in the downstream of the pretilt angle direction of the liquid crystal molecule with respect to the source signal line, The four pixel electrodes are positioned upstream of the pretilt angle direction of the liquid crystal molecules with respect to the source signal lines and the overlap width of the third pixel electrode and the source signal line is larger than the overlap width of the fourth pixel electrode and the source signal line.

In another embodiment of the present invention, the liquid crystal display is driven by the dot inversion driving method.

Alternatively, the liquid crystal display of the present invention includes a gate electrode, a source signal line intersecting the gate signal line, an interlayer insulating film formed on the gate signal line and the source signal line, and a pixel electrode formed on the interlayer insulating film, And a first region and a second region of each pixel electrode are partially overlapped with at least one of a gate signal line and a source signal line, And the overlap width of the signal line and the first region is different from the overlap width of the signal line and the second region and the boundary portion of the first region and the second region is covered with the shielding film crossing the signal lines.

In one embodiment of the present invention, the signal line is a source signal line, the source signal line is located downstream in the pretilt angle direction of the liquid crystal molecules in the first region, and the source signal line is the liquid crystal molecules The overlap width of the source signal line and the second region is larger than the overlap width of the source signal line and the first region.

In another embodiment of the present invention, the signal line is substantially linear, and the edge of the first area of the pixel electrode overlapping the signal line is offset from the edge of the second area overlapping the signal line.

In another embodiment of the present invention, the end of a portion of the signal lines overlapping the first region is excluded from the end of a portion of the signal lines overlapping with the second region, Is aligned with the edge of the second region that overlaps the signal line.

In another embodiment of the present invention, the liquid crystal display is driven by a source line driving method or a dot inversion driving method.

Alternatively, the liquid crystal display device of the present invention may include a gate signal, a source signal line intersecting the gate signal line, an interlayer insulating film formed on the gate signal line and the source signal line, a pixel electrode formed on the interlayer insulating film, And a drain electrode connected to the corresponding pixel electrode via a hole, wherein each of the connection holes is formed on a shielding signal line located below the corresponding drain electrode, and the central axis of the connection hole is offset from the central axis of the shielding signal line have.

In one embodiment of the present invention, the central axis of the connection hole is offset by a certain distance in the pretilt angle direction of the liquid crystal molecules from the central axis of the shielding signal line.

In another embodiment of the present invention, the distance between the central axis of the connection hole and the central axis of the shielding signal line is in the range of about 0.5 to about 1.5 mu m.

In another embodiment of the present invention, the gate electrode of each switching element is located at the center of the corresponding pixel electrode portion, and the shielding signal line is provided between the pixel electrode and the adjacent pixel electrode in the direction opposite to the pretilt angle direction of the liquid crystal molecule .

In another embodiment of the present invention, the shielding signal line forms the gate electrode of each switching element, which is located between the pixel electrode and the adjacent pixel electrode in a direction opposite to the pretilt angle direction of the liquid crystal molecule .

Therefore, according to the embodiment of the liquid crystal display of the present invention, the overlap width of the gate signal line and the first pixel electrode is different from the overlap width of the gate signal line and the second pixel electrode. Typically, the overlap width of the gate signal line and the first pixel electrode is larger than the overlap width of the gate signal line and the second pixel electrode. In the case of a liquid crystal display device using a gate line inversion driving method, the overlapping portion of the first pixel electrode among the two pixel electrodes sandwiching each gate signal line located in the downstream of the pretilt angle direction (alignment direction) A reverse tilt zone tends to be generated. In the liquid crystal display device of this embodiment, the reverse tilt region generated by the electric field generated between the adjacent pixel electrodes is covered with a large overlap width by the overlapped portion of the gate signal line and the first pixel electrode. Therefore, the liquid crystal display device of this embodiment can prevent the light leakage due to the generation of the reverse-tilt zone when the gate line inversion method is driven while maintaining a high aperture ratio.

According to another embodiment of the liquid crystal display of the present invention, the overlap width of the source signal line and the third pixel electrode is different from the overlap width of the source signal line and the fourth pixel electrode. Typically, the overlap width of the source signal line and the third pixel electrode is larger than the overlap width of the source signal line and the fourth pixel electrode. In the case of the liquid crystal display device using the source line inversion driving method, in the overlapping portion of the third pixel electrode among the two pixel electrodes switching each source signal line located in the downstream of the pretilt angle direction (alignment direction) of the liquid crystal molecules A reverse tilt zone tends to be generated. In the liquid crystal display device of this embodiment, the reverse tilt region generated by the electric field generated between the adjacent pixel electrodes is covered with a large overlap width by the overlapped portion of the source signal line and the third pixel electrode. Therefore, the liquid crystal display device of this embodiment can prevent light leakage due to the generation of the reverse tilt region when driven by the source line inversion method while maintaining a high aperture ratio.

According to another embodiment of the liquid crystal display of the present invention, the overlap width of the gate signal line and the first pixel electrode is different from the overlap width of the gate signal line and the second pixel electrode, The overlap width is different from the overlap width of the source signal line and the fourth pixel electrode. Typically, the overlap width of the gate signal line and the first pixel electrode is configured to be larger than the overlap width of the gate signal line and the second pixel electrode, and the overlap width of the source signal line and the third pixel electrode is larger than the overlap width of the source signal line and the fourth Is larger than the overlap width of the pixel electrode. In the case of the liquid crystal display device using the dot inversion driving method, the overlapping portion of the first pixel electrode among the two pixel electrodes sandwiching each gate signal line located in the downstream of the pretilt angle direction (alignment direction) , A reverse tilt region tends to be generated in the overlapped portion of the third pixel electrode among the two pixel electrodes sandwiching each source signal line located in the downstream of the pretilt angle direction (alignment direction) of the liquid crystal molecules. In the liquid crystal display device of this embodiment, the reverse tilt region generated by the electric field generated between the adjacent pixel electrodes is covered with a large overlap width by the overlapping portion of the gate signal line and the first pixel electrode, And the overlapping portion of the third pixel electrode. Therefore, the liquid crystal display device of this embodiment can prevent the light leakage due to the generation of the reverse tilt region when driven by the dot inversion method while maintaining the high aperture ratio.

According to another embodiment of the liquid crystal display of the present invention, each pixel electrode has adjacent first and second regions having liquid crystal molecules in different alignment directions. The overlap width of the signal line and the first region is different from the overlap width of the signal line and the second region. The boundary portions of the first and second regions are covered with a light shielding film formed so as to cross the signal lines. For example, the first and second regions of the pixel electrode are overlapped with the source signal line, and the source signal line is located downstream of the pretilt angular direction (alignment direction) of the liquid crystal molecules in the first region with respect to the first region While the source signal line is positioned upstream of the pretilt angular direction (alignment direction) of the liquid crystal molecules in the second region with respect to the second region. In this case, a reverse tilt zone is generated in the second area on the source signal line side. According to the present invention, typically, the overlap width of the source signal line and the second region is configured to be larger than the overlap width of the source signal line and the first region. According to such a configuration, the reverse-tilt zone generated in the overlapping portion with the source signal line can be well shielded by the overlapping portion of the wide width. Further, since the boundary portions of the first and second regions are covered with the light shielding film, light leakage from the boundary portion can be prevented.

According to another embodiment of the liquid crystal display device of the present invention, each connection hole is covered with a shielding signal line below the drain electrode, and the center axis of the connection hole does not coincide with the center axis of the shielding signal line. Typically, the center axis of each connection hole is offset in the pretilt angle direction of the liquid crystal molecules from the central axis of the shielding signal line. Therefore, the reverse-tilt zone generated at the connection hole or at the periphery thereof is completely covered by the shielding signal line. Thus, the liquid crystal display device of this embodiment can prevent the light leakage due to the generation of the reverse tilt zone while maintaining the high aperture ratio.

Therefore, the present invention provides (1) a liquid crystal display of high aperture ratio that can prevent light leakage due to generation of a reverse tilt zone between a gate signal line and a pixel electrode and / or between a source signal line and a pixel electrode, (2) To provide a liquid crystal display device with a high aperture ratio that can prevent light leakage due to the generation of a reverse tilt region even if any of the gate line inversion driving method, the source line inversion driving method, and the dot inversion driving method is used. 3) It is possible to provide a liquid crystal display device having a high aperture ratio that can prevent light leakage due to generation of a reverse tilt zone at a connection hole or a peripheral portion thereof regardless of the thickness of the interlayer insulating film.

These and other advantages of the present invention will become apparent from the detailed description of the invention with reference to the accompanying drawings.

1 is a plan view of a pixel of a liquid crystal display device according to an embodiment of the present invention;

FIG. 2A is a cross-sectional view of a liquid crystal display device taken along the line A-A 'in FIG. 1; FIG.

FIG. 2B is a cross-sectional view of the liquid crystal display device taken along the line B-B 'in FIG. 1; FIG.

FIG. 3A is an enlarged plan view of the region X of FIG. 1 where the gate signal line and the source signal line intersect; FIG.

FIG. 3B is a cross-sectional view of the liquid crystal display taken along the line C-C 'in FIG. 3A. FIG.

4 shows a gate line inversion driving method used in a liquid crystal display according to the present invention.

FIG. 5 is a plan view of an intersection of a gate signal line and a source signal line, illustrating a region where a reverse tilt region is generated in a body of a signal line and a pixel electrode when the liquid crystal display device is driven by a gate line inversion driving method;

6 illustrates a source line inversion driving method used in a liquid crystal display device according to the present invention.

7 is a plan view of an intersection of a gate signal line and a source signal line, illustrating a region in which a reverse tilt region is generated in a body of a signal line and a pixel electrode when the liquid crystal display device is driven by a source line inversion driving method;

8 illustrates a dot inversion driving method used in a liquid crystal display device according to the present invention.

9 is a plan view of an intersection of a gate signal line and a source signal line, illustrating a region in which a reverse tilt region is generated in a body of a signal line and a pixel electrode when a liquid crystal display device is driven by a dot inversion driving method;

10 is a plan view of one pixel of a liquid crystal display device according to another embodiment of the present invention.

11A is a cross-sectional view of the liquid crystal display taken along the line A-A 'in FIG.

11B is a cross-sectional view of the liquid crystal display device taken along line B-B 'in FIG.

12A is an enlarged plan view of the region Y of FIG. 10 where the source signal line and the storage capacitor electrode cross each other;

12B is a cross-sectional view taken along the line C-C 'in FIG. 12A;

12C is a sectional view taken along the line D-D 'in FIG.

13 is a plan view of one pixel of a liquid crystal display device according to still another embodiment of the present invention.

14A is a cross-sectional view of the liquid crystal display device taken along the line A-A 'in FIG.

FIG. 14B is a cross-sectional view of the liquid crystal display taken along the line B-B 'in FIG. 13; FIG.

15A is an enlarged plan view of a region Y of FIG. 13 in which a source signal line and a storage capacitor electrode cross each other;

FIG. 15B is a cross-sectional view taken along the line C-C 'in FIG. 15A. FIG.

15C is a cross-sectional view taken along the line D-D 'in FIG. 15A

16A is a plan view of a pixel of a liquid crystal display device according to still another embodiment of the present invention.

FIG. 16B is a plan view of a region around the connection hole, which describes the terms "center axis of the connection hole", "center axis of the storage capacitor electrode", and "center axis of the shield line" used herein.

17 is a cross-sectional view of the liquid crystal display device taken along the line A-A 'in FIG. 16A;

FIG. 18 is a cross-sectional view of the liquid crystal display taken along the line B-B 'in FIG. 16A; FIG.

19 is a plan view of one pixel of a liquid crystal display device according to still another embodiment of the present invention.

20 is a cross-sectional view of the liquid crystal display device taken along the line A-A 'in FIG. 19;

21 is a sectional view of the liquid crystal display device taken along the line B-B 'in FIG. 19;

22 is a plan view of one pixel of a liquid crystal display device according to still another embodiment of the present invention;

23 is a sectional view of the liquid crystal display device taken along the line A-A 'in Fig.

24 is a sectional view of the liquid crystal display device taken along the line B-B 'in FIG.

25 is a plan view of one pixel of a liquid crystal display device according to still another embodiment of the present invention.

26 is an equivalent circuit diagram of a conventional active matrix substrate;

27 is a plan view of one pixel of a conventional liquid crystal display device.

28 is a cross-sectional view of a conventional liquid crystal display device taken along the line A-A 'in FIG. 27;

29 is a sectional view of a conventional liquid crystal display device taken along the line B-B 'in FIG. 27;

30A is an enlarged plan view of a region of a conventional liquid crystal display device in which a gate signal line and a source signal line intersect.

30B is a cross-sectional view taken along the line C-C 'in FIG. 30A.

31A is an enlarged plan view of a region of a conventional liquid crystal display device in which a gate signal line and a source signal line intersect.

31B is a cross-sectional view taken along the line C-C 'in FIG. 31A;

31C is a sectional view taken along the line D-D 'in FIG.

Description of the Related Art

102: source signal line

103: Gate insulating film

104: gate signal line

112: liquid crystal layer

120: transparent insulating substrate

126: storage capacitor electrode

128: channel protection layer

Hereinafter, the present invention will be described in detail by way of example with reference to the accompanying drawings, wherein like reference numerals refer to like parts.

(Example 1)

1 is a plan view of a pixel of a liquid crystal display device according to an embodiment of the present invention. 2A is a cross-sectional view taken along line A-A 'of FIG. 1, and FIG. 2B is a cross-sectional view taken along line B-B' of FIG. FIG. 3A is an enlarged plan view of region X of FIG. 1 where gate signal line 104 and source signal line 102 intersect. 3B is a cross-sectional view taken along the line C-C 'of FIG. 3A, illustrating the superposition of the gate signal line 104 and the source signal line 102 and the pixel electrode 140. FIG.

The manufacture of a liquid crystal display device according to the present invention will be described.

First, an active matrix substrate is manufactured as follows. A gate signal line 104, a storage capacitor electrode 126, a gate insulating film 103, a semiconductor layer 134, a channel protective layer 128, and a gate electrode are formed on a transparent insulating substrate 120 made of glass or the like, And the n ⁺ -Si layer 130 serving as the source and drain electrodes are formed according to a known method in the order described. As shown in FIG. 1, one storage capacitor electrode 126 is formed for each row of pixels across the pixel substantially parallel to the gate signal line 104.

Thereafter, an ITO film 132 and a metal layer 133, which are transparent conductive films, are formed by sputtering and patterned to form the source signal line 102. In this embodiment, each source signal line 102 is preferably a bilayer structure made up of an ITO film 132 and a metal layer 133. This double dam structure is advantageous in that, for example, even if the metal layer 133 is broken, the possibility of disconnecting the source signal line is reduced because the source signal line 102 is still connected through the ITO film 132. [

After forming the layers constituting the source signal lines on the substrate 120, an interlayer insulating film 136 made of acrylic resin or the like is preferably formed to a thickness of about 2 탆 to about 4 탆. Next, a connection hole 142 is formed at a predetermined position through the interlayer insulating film 136. [

A transparent conductive film made of an ITO film or the like is formed on the interlayer insulating film 136 by, for example, sputtering, and patterned to form the pixel electrode 140. Each pixel electrode 140 is connected to the ITO layer 132 under the via hole 142 and the ITO layer 132 is connected to the drain electrode of the TFT, that is, the n ⁺ -Si layer 130 .

A process of forming the pixel electrode 140 on the interlayer insulating film 136 will be described.

3A and 3B, in this embodiment, when the pretilt angle direction (alignment direction D ₁ of the liquid crystal molecules 152a) of the liquid crystal molecules 152a is determined, the interlayer insulating film 136 The pixel electrodes 140a and 140b are formed so as to overlap with the overlap widths dg1 and dg2 which are different from the gate signal line 104 and the source signal line 102. In particular, ) and, overlapping width dg1 of the gate signal line 104, the pixel electrode (140a) located below the alignment direction D ₁ for the pixel electrode located upstream of the gate signal line 104, the alignment direction D ₁ ( The overlap widths dg1 and dg2 are about 3 占 퐉 and about 1 占 퐉, respectively, and the distance between the pixel electrode 140a and the pixel electrode 140b is larger than the overlap width dg2 between the pixel electrode 140a and the pixel electrode 140b Lt; / RTI >

Such a liquid crystal display that satisfies the relationship between the overlap widths dg1 and dg2 is a gate line inversion driving method (an inversion driving method illustrated in Fig. 4 in which pixel signals are inverted every gate line 105, i.e., every horizontal (1H) Lt; / RTI > 5 is a plan view showing an intersection of the gate signal line 104 and the source signal line 102 of the liquid crystal display device driven by the gate line inversion driving method. As shown in Fig. 5, the generated reverse tilt zone 154 is well covered by the overlapped portion of the gate signal line 104 and the pixel electrodes 140a and 140d, so that light leakage does not occur.

Alternatively, when the pretilt angle direction (alignment direction D ₁ of the liquid crystal molecules 152a) of the liquid crystal molecules 152a is determined, the pixel electrodes 140a and 140d (pixel electrodes 140b and 140c - a gate signal line (104) and a source signal line 102 and different overlap width ds1 and is formed such that each overlap as ds2. Specifically, source signal line downstream the alignment direction D ₁ with respect to the source signal line 102 ( 102) overlap width ds1 of the pixel electrode (140a) positioned on a preferably larger than the overlapping width ds2 of the pixel electrode (140d) positioned on the source signal line 102 at the upstream of the alignment direction D ₁ (ds1> For example, the overlap widths ds1 and ds2 are about 3 占 퐉 and about 1 占 퐉, respectively, and the distance between the pixel electrodes 140a and 140d is about 5 占 퐉.

Such a liquid crystal display that satisfies the relationship between the overlap widths ds1 and ds2 can be used in a source line inversion driving method (a method in which signals of opposite polarity are input to the adjacent source signal line 102, The inversion driving method illustrated in Fig. 6 in which the polarities are different). 7 is a plan view showing an intersection of the gate signal line 104 and the source signal line 102 of the liquid crystal display device driven by the source line inversion driving method. As shown in Fig. 7, the generated reverse tilt region 154 is satisfactorily covered by the overlapped portion of the source signal line 102 and the pixel electrodes 140a and 140b, so that light leakage does not occur.

Alternatively, when the pretilt angle direction (alignment direction D ₁ of the liquid crystal molecules 152a) of the liquid crystal molecules 152a is determined, the pixel electrodes 140a, 140b, 140c, and 140d are connected to the gate signal The pixel electrodes 140a and 140b (and the pixel electrodes 140d and 140c) are formed so as to overlap with the gate signal line 104 and the source signal line 102 such that they overlap with the overlap widths dg1 and dg2, And the pixel electrodes 140a and 140d (and the pixel electrodes 140b and 140c) are formed to overlap with the overlap widths ds1 and ds2, which are different from the source signal line 102. Particularly, for the gate signal line 104 the overlap width dg1 is a pixel electrode (140b) located on a gate signal line 104 in the upstream of the alignment direction D ₁ of the pixel electrode (140a) located on the gate signal line 104, downstream of the alignment direction D ₁ (Dg1 > dg2), it is preferable that the width of the alignment signal line 102 is larger than the overlap width dg2 Overlap of the pixel electrode (140a) located on the source signal line 102 downstream of the direction D ₁ width ds1 is overlap of the pixel electrode (140d) positioned on the source signal line 102 at the upstream of the alignment direction D ₁ For example, the overlap widths dg1 and ds1 are about 3 占 퐉, the overlap widths dg2 and ds2 are about 1 占 퐉, and the distance between the pixel electrodes is about 5 占 퐉 (ds1> ds2).

Such a liquid crystal display that satisfies the relationship between the overlap widths dg1 and dg2 and the overlap widths ds1 and ds2 is applicable to the dot inversion driving method (the inversion driving method illustrated in Fig. 8, which combines the gate line inversion driving method and the source line inversion driving method) Lt; / RTI > 9 is a plan view showing intersections of the gate signal line 104 and the source signal line 102 of the liquid crystal display device driven by the dot inversion driving method. 9, the generated reverse tilt region 154 is formed by overlapping the overlapping portions of the gate signal line 104 and the pixel electrodes 140a and 140d and the overlapping portions of the source signal line 102 and the pixel electrodes 140a and 140b Is covered by the overlapping portion, and light leakage does not occur.

Generally, in the overlapping portion of the gate signal line 104 and the pixel electrode 140a and the overlapping portion of the source signal line 102 and the pixel electrode 140a due to the electric field generated between the adjacent pixel electrodes, for example, A reverse tilt zone 154 is created with a width of about 1 [mu] m to about 2 [mu] m. Although the overlap width values dg1 and ds1 are not particularly limited, the size of the generated reverse tilt region, the processing precision of the gate signal line and the source signal line, the overlapping precision of the gate and source signal lines and the pixel electrode, It changes according to precision. And may be set to a value obtained by adding a tolerance of about 0.75 mu m to about 1 mu m for the stability of the width of the reverse tilt zone. The overlap width dg1 is preferably in the range of about 2 [mu] m to about 4 [mu] m, typically about 3 [mu] m. The overlap width ds1 is preferably in the range of about 2 탆 to about 4 탆, typically about 3 탆.

The magnitude of the electric field generated between adjacent pixel electrodes changes as the width of the pixel electrode changes, and the width of the generated reverse tilt region changes. Therefore, the width of the pixel electrode should be selected to be large enough to cover the width of the generated reverse-tilt zone. The width of the pixel electrode is also selected according to the potential applied to the pixel electrode. For example, when the potentials of 5 V and -5 V are applied to the pixel electrode in the inversion driving, a reverse tilt region having a width of 1 mu m to 1.5 mu m is generated. When a potential having a large absolute value is applied, a reverse tilt region having a larger width is generated. Conversely, when a potential having a small absolute value is applied, a reverse tilt region having a smaller width is generated. The distance between adjacent pixel electrodes is not particularly limited, but is preferably in the range of about 4 탆 to about 6 탆.

Subsequent to the formation of the pixel electrode, an orientation film 150 is formed on the interlayer insulating film 136 to perform rubbing treatment. Thereby, an active matrix substrate is obtained.

Next, the counter substrate is manufactured in the following manner. An opposing substrate can be manufactured before the production of the active matrix substrate.

Referring again to FIGS. 2A and 2B, a metal film made of Ta, Cr, Al, or the like is formed on a transparent insulating substrate 122 made of glass or the like by sputtering and patterned to form a light shielding layer 144. Next, a light-sensitive color resist is applied to a portion of the substrate 122 on which the light-shielding layer 144 is not formed, exposed, and developed to form a color layer 146 representing red, green, and blue. As a result, each color layer 146 is surrounded by the light shielding layer 144. Next, on the light-shielding layer 144 and the color layer 146, for example, a counter electrode 148 made of ITO or the like is formed into a predetermined shape by sputtering. Next, an alignment film 150 is formed on the counter electrode 148 to perform a rubbing process. Thus, a counter substrate is obtained.

As shown in Fig. 2B, the active matrix substrate and the counter substrate are laminated together in a known manner so as to face each other with the orientation film 150. [ The gap (cell gap) between the active matrix substrate and the opposing substrate is, for example, about 4.5 mu m, but such a value is not particularly limited and can be arbitrarily selected. After the substrate is laminated, a liquid crystal material is injected into the gap by a known method to form the liquid crystal layer 112. [ Thus, a liquid crystal display device according to the present invention is obtained.

In this embodiment, the reverse tilt region 154 shown in FIG. 3B, which is generated due to an electric field generated between adjacent pixel electrodes, is formed by overlapping portions of the gate signal line 104 and the pixel electrode 140 and / And is formed in the overlapped portion of the signal line 102 and the pixel electrode 140, so that it is shielded. Therefore, light leakage from the reverse tilt zone is prevented, and the liquid crystal display device manufactured according to the present invention exhibits excellent display characteristics. Further, in the liquid crystal display device of this embodiment, since the light leakage from the reverse tilt region can be minimized without expanding the shielding region, a high aperture ratio can be maintained.

In a 12.1 inch VGA display, the width of the gate signal lines, the distance between the pixel electrodes sandwiching the gate signal lines, the width of the source signal lines, and the distance between the pixel electrodes sandwiching the source signal lines are 18 mu m, 14 mu m, 8 mu m And 4 mu m, and the cell gap between the pixel electrode of the active matrix substrate and the opposing electrode of the counter substrate is unchanged, that is, 4.5 mu m. In this case, a reverse tilt region is generated even if the cell gap is shorter than the distance between the pixel electrodes sandwiching the gate signal line. Even in this case, the generated reverse tilt zone can be shielded according to the present invention.

In this embodiment, a liquid crystal display device in which liquid crystal molecules are uniformly oriented in a predetermined direction is described. However, the present invention is not limited to this kind, but may be applied to a liquid crystal display device in which one pixel is divided into a plurality of portions having different liquid crystal molecule orientations in order to maintain good visibility in view of wide viewing angle, It can also be applied to devices. According to the present invention, the configuration of the overlapping portion of the signal line and each pixel electrode is determined according to the alignment direction of the liquid crystal molecules. Therefore, when each pixel is divided into a plurality of portions, the configuration of the overlapping portion of the signal line and the pixel electrode must be changed in accordance with the alignment direction of the liquid crystal molecules in the vicinity of the pixel electrode.

(Example 2)

10 is a plan view of one pixel of a liquid crystal display device according to another embodiment of the present invention. FIG. 11A is a cross-sectional view of the liquid crystal display taken along the line A-A 'of FIG. 10, and FIG. 11B is a cross-sectional view of the liquid crystal display taken along the line B-B' of FIG. 12A is an enlarged plan view of the region Y of FIG. 10 where the source signal line 102 and the storage capacitor electrode 126 intersect each other. 12B is a cross-sectional view taken along line C-C 'of FIG. 12A in which the pixel electrode 140 overlaps with the source signal line 102, and FIG. 12C is a cross-sectional view of the pixel electrode 140 overlapping the source signal line 102 Sectional view taken along line D-D 'in FIG. 12A.

As shown in Fig. 12A, each pixel of the liquid crystal display of this embodiment is divided into two regions along the line corresponding to the storage capacitor electrode 126. Fig. The boundary between the two regions is shielded by the storage capacitor electrode 126. The two regions have different alignment directions D ₁ and D ₂ of the liquid crystal molecules 152a (see, for example, FIG. 12B), and the overlap width of the source signal line 102 and the corresponding two regions of the pixel electrode, Direction D ₁ and D ₂ .

The storage capacitor electrode 126 spans the entire pixel substantially parallel to the gate signal line 104, as shown in Fig. One storage capacitor electrode 126 is provided for each row of pixels.

12A and 12B, when different alignment directions D ₁ and D ₂ of the liquid crystal molecules 152a are provided as described above, the pixel electrode 140 and the corresponding source signal line 102 are adjusted as follows. That is, the overlap widths d1 and d3 of the source signal line 102 and the region of the pixel electrode 140 located downstream of the alignment direction of the liquid crystal molecules 152a (the pretilt angle direction) And the overlap widths d2 and d4 of the region of the pixel electrode 140 positioned upstream of the alignment direction of the liquid crystal molecules 152a. The overlap widths d1 and d3 are preferably equal to each other. Also, the overlap widths d2 and d4 are preferably equal to each other. The overlap widths d1 and d3 are not particularly limited, but are preferably in the range of about 2.5 占 퐉 to about 3.5 占 퐉, typically about 3 占 퐉. The overlap widths d2 and d4 are not particularly limited, but are preferably in the range of about 0.5 占 퐉 to about 1.5 占 퐉, typically about 1 占 퐉.

The electric field generated between adjacent pixel electrodes changes as the width of the pixel electrode changes, and the width of the generated reverse tilt region changes. Therefore, the width of the pixel electrode should be selected to be large enough to cover the width of the generated reverse-tilt zone. The distance between adjacent pixel electrodes is not particularly limited, but is preferably in the range of about 4 占 퐉 to about 6 占 퐉, typically about 5 占 퐉.

In this embodiment, as shown in Fig. 12A, the source signal line 102 is almost linear. An edge of a region of the pixel electrode 140, the liquid crystal molecules that are in alignment direction D ₁ which overlaps with the source signal line 102 is a pixel in the liquid crystal molecules are in the alignment direction D _2, which overlap with the source signal line 102 Is offset from the edge of the other region of the electrode (140).

When the liquid crystal display device having the above structure is driven by the dot inversion driving method as shown in Figs. 12B and 12C, the liquid crystal molecules are generated by the electric field generated between the adjacent pixel electrodes, A reverse tilt zone is generated which is tilted backward as shown in FIG. However, since such a reverse tilt region is generated in the overlapping portion of the source signal line 102 and the pixel electrode 140, it can be shielded by the overlap region. Therefore, in the liquid crystal display device of this embodiment, light leakage from the reverse tilt region can be prevented, and excellent display characteristics are exhibited. Further, in the liquid crystal display device of this embodiment, the light leakage from the reverse tilt region can be minimized without enlarging the light shielding region, so that the high aperture ratio can be maintained. This is also due to the electric field generated between the adjacent pixel electrodes sandwiching the source signal line 102, which is generated at the intersection of the source signal line 102 and the gate signal line 104, It can also be applied to tilt zone.

The same effect can be obtained when the liquid crystal display device of this embodiment is driven by the source line inversion driving method.

(Example 3)

13 is a plan view of one pixel of a liquid crystal display device according to another embodiment of the present invention. FIG. 14A is a cross-sectional view of the liquid crystal display taken along line A-A 'of FIG. 13, and FIG. 14B is a cross-sectional view of the liquid crystal display taken along line B-B' of FIG. 15A is an enlarged plan view of the region Y of FIG. 13 where the source signal line 102 and the storage capacitor electrode 126 intersect each other. 15B is a cross-sectional view taken along the line C-C 'of FIG. 15A in which the pixel electrode 140 overlaps the source signal line 102, and FIG. 15C is a cross-sectional view in which the pixel electrode 140 overlaps with the source signal line 102 Sectional view taken along the line D-D 'in Fig. 15A

As shown in Fig. 15A, each pixel of the liquid crystal display of this embodiment is divided into two regions along the line corresponding to the storage capacitor electrode 126. Fig. The boundary between the two regions is shielded by the storage capacitor electrode 126. The two regions have different alignment directions D ₁ and D ₂ of the liquid crystal molecules 152a (see, for example, FIG. 15B), and the overlap width of the source signal line 102 and the corresponding two regions of the pixel electrode, Direction D ₁ and D ₂ .

The storage capacitor electrode 126 spans the entire pixel substantially parallel to the gate signal line 104, as shown in Fig. One storage capacitor electrode 126 is provided for each row of pixels.

15A and 15B, when the different alignment directions D ₁ and D ₂ of the liquid crystal molecules 152a are provided as described above, the pixel electrode 140 and the corresponding source signal line 102 are adjusted as follows. That is, the overlap widths d1 and d3 of the source signal line 102 and the region of the pixel electrode 140 located downstream of the alignment direction of the liquid crystal molecules 152a (the pretilt angle direction) And the overlap widths d2 and d4 of the region of the pixel electrode 140 positioned upstream of the alignment direction of the liquid crystal molecules 152a. The overlap widths d1 and d3 are preferably equal to each other. Also, the overlap widths d2 and d4 are preferably equal to each other. The overlap widths d1 and d3 are not particularly limited, but are preferably in the range of about 2.5 占 퐉 to about 3.5 占 퐉, typically about 3 占 퐉. The overlap widths d2 and d4 are not particularly limited, but are preferably in the range of about 0.5 占 퐉 to about 1.5 占 퐉, typically about 1 占 퐉.

The electric field generated between adjacent pixel electrodes changes as the width of the pixel electrode changes, and the width of the generated reverse tilt region changes. Therefore, the width of the pixel electrode should be selected to be large enough to cover the width of the generated reverse-tilt zone. The distance between adjacent pixel electrodes is not particularly limited, but is preferably in the range of about 4 占 퐉 to about 6 占 퐉, typically about 5 占 퐉.

The liquid crystal display device of this embodiment is preferably configured as follows. 15A, the edge of one region of the pixel electrode 140 in which the liquid crystal molecules overlap with the source signal line 102 in the alignment direction D ₁ causes the liquid crystal molecules to overlap with the source signal line 102 And is aligned with the edge of another region of the pixel electrode 140 in the alignment direction D ₂ . Conversely, the end regions of the source signal line 102 corresponding to the area having the orientation direction D ₁ is offset from the ends of the region of the source signal line 102 corresponding to the area having the orientation direction D ₂ (i.e., The source signal line 102 is bent).

When the liquid crystal display device having the above configuration is driven by the dot inversion driving method as shown in Figs. 15B and 15C, due to the electric field generated between the adjacent pixel electrodes sandwiching the source signal line 102, A reverse tilt zone is created in which the molecules are tilted backwards as indicated by reference numeral 152b. However, since such a reverse tilt region is generated in the overlapping portion of the source signal line 102 and the pixel electrode 140, it can be shielded by the overlap region. Therefore, in the liquid crystal display device of this embodiment, light leakage from the reverse tilt region can be prevented, and excellent display characteristics are exhibited. Further, in the liquid crystal display device of this embodiment, the light leakage from the reverse tilt region can be minimized without enlarging the light shielding region, so that the high aperture ratio can be maintained. This is also due to the electric field generated between the adjacent pixel electrodes sandwiching the source signal line 102, which is generated at the intersection of the source signal line 102 and the gate signal line 104, It can also be applied to tilt zone.

The same effect can be obtained when the liquid crystal display device of this embodiment is driven by the source line inversion driving method.

In Examples 2 and 3, each pixel was vertically divided into first and second regions aligned along the source signal lines and having different alignment directions of liquid crystal molecules. Alternatively, the pixels may be divided in different directions. Embodiments 2 and 3 can also be applied to a liquid crystal display device in which each pixel is divided into first and second regions aligned along gate signal lines and having different liquid crystal molecule alignment directions. In this case, the configuration of the overlapping portions of the signal lines corresponding to the first and second regions of the pixel electrode must be determined according to the alignment direction of the affinity molecules in the first and second regions.

In Embodiments 2 and 3, the boundary portions of the first and second regions having different alignment directions of the liquid crystal molecules are shielded by the storage capacitor electrode 126. When the boundary portions of the first and second regions are at different positions, an additional light shielding portion may be provided to shield the boundary portion. For example, in the case of a liquid crystal display device in which each pixel is divided into regions aligned along the gate signal line, a light shielding portion may be provided in the direction of the source signal line across each pixel electrode.

Further, in Embodiments 2 and 3, the overlap width of the pixel electrode and the signal lines is set such that the reverse tilt region is generated by any of the flip-flip driving method, the gate line driving method, the source line driving method and the dot inversion driving method Can be changed according to the area. This can be combined with the overlapping portion of the pixel electrode and the source signal line and the overlapping portion of the pixel electrode and the gate signal line shown in Embodiment 1. [

In the liquid crystal display devices of Examples 1 to 3, each pixel electrode is insulated by the corresponding source and gate signal lines and the interlayer insulating film, and the pixel electrode is connected to the drain electrode of the corresponding TFT through the connection hole formed through the interlayer insulating film POP structure. The present invention also relates to a liquid crystal display device having no POP structure, for example, to ensure insulation between each pixel electrode and a corresponding gate and source signal line, and to ensure that the pixel electrode is connected to the drain electrode of the corresponding TFT The present invention can be applied to a liquid crystal display device in which an insulating film thinner than an interlayer insulating film is formed.

(Example 4)

16A is a plan view of one pixel of a liquid crystal display device according to still another embodiment of the present invention. 16B is an enlarged plan view of a peripheral region of the connection hole in Fig. 16A. Fig. FIG. 17 is a cross-sectional view of the liquid crystal display taken along the line A-A 'in FIG. 16A, and FIG. 18 is a cross-sectional view of the liquid crystal display taken along the line B-B' in FIG. 16A.

16A and 17, the connection hole 142 is formed on the storage capacitor electrode 126 below the elongated drain electrode 125 in the liquid crystal display device of this embodiment. However, the center axis 160 of the connection hole 142 is offset from the center axis 156 of the storage capacitor electrode 126. 16B, the term " central axis of the connection hole " as used herein refers to a direction perpendicular to the plane of Fig. 16B from the center O (160) of an outer circle of a connection hole having an arbitrary shape Axis, the term " center axis of storage capacitor electrode " and the term " shielding signal line " refer to an axis extending from the center O 'of the circumscribed circle of the generated reverse tilt zone 154 in a direction perpendicular to the plane of FIG. It is saying.

The center axis 160 of the connection hole 142 is offset from the central axis 156 of the storage capacitor electrode 126 to the alignment direction D ₃ (pretilt angular direction) of the liquid crystal molecules 152a . The distance between the central axis 160 and the central axis 156 is preferably in the range of about 0.5 占 퐉 to about 1.5 占 퐉, typically about 1.5 占 퐉. The reverse tilt zone is generated at a position where its center portion is offset from the central axis 160 of the connection hole 142 in a direction opposite to the alignment direction D ₃ of the liquid crystal molecules 152a. Thus, the generated reverse tilt zone is located on the storage capacitor electrode 126. Therefore, light leakage from the reverse tilt zone can be effectively prevented by the storage capacitor electrode 126. [ In the liquid crystal display device of this embodiment, the line width of the storage capacitor electrode 126 can be minimized and the high aperture ratio can be maintained.

The manufacture of the liquid crystal display device of this embodiment will be described with reference to Figs. 17 and 18. Fig.

First, an active matrix substrate is manufactured as follows. A gate electrode line 104, a storage capacitor electrode 126, a gate insulating film 103, a semiconductor layer 134, a channel protection layer (not shown), and a gate insulating film 103 are formed on a transparent insulating substrate 120 made of glass, And the n ⁺ -Si layer 130 serving as a source electrode and a drain electrode are formed in the described order. In this embodiment, as shown in Fig. 16A, one storage capacitor electrode 126 is formed for each row of pixels across the pixel, substantially parallel to the gate signal line 104. In Fig.

Thereafter, an ITO film 132 and a metal layer 133, which are transparent conductive films, are formed by sputtering and patterned to form the source signal line 102. In this embodiment, each source signal line 102 is preferably a bilayer structure made up of an ITO film 132 and a metal layer 133. This double dam structure is advantageous in that, for example, even if the metal layer 133 is broken, the possibility of disconnecting the source signal line is reduced because the source signal line 102 is still connected through the ITO film 132. [

After forming the layers constituting the source signal lines on the substrate 120, the interlayer insulating film 136 made of acrylic resin or the like is preferably formed to a thickness of about 2 탆 to about 4 탆, typically about 3 탆 . Next, the pixel electrode 140 is formed on the interlayer insulating film 136 by a known method or a known method. Next, an orientation film 150 is formed on the interlayer insulating film 136 to perform rubbing treatment.

Next, a connection hole 142 is formed at a predetermined position through an interlayer insulating film 136 by a predetermined method. The angle? Of the inclined inner wall of each connection hole 142 is preferably between about 45 or more and less than about 65. [ The diameter? Of the connection hole 142 is preferably about 3.5 占 퐉 to about 6 占 퐉, typically about 4 占 퐉. Due to the above-described configuration, the storage capacitor electrode 126 can effectively prevent light leakage from the reverse-tilt zone 154 as described above. Therefore, in the case of the liquid crystal display device of this embodiment, the line width of the storage capacitor electrode 126 can be minimized and the high aperture ratio can be maintained.

In this embodiment, the line width L of each storage capacitor electrode 126 is expressed by the following equation (1).

Here, d is the thickness of the interlayer insulating film 136,? Indicates the angle of the inclined inner wall of the connection hole 142,? Indicates the diameter of the connection hole 142, and n indicates the minimum light from the reverse tilt region Represents the minimum width of the light-shielding film necessary to prevent leakage.

As can be seen from the formula (1), in order to decrease the line width L of the storage capacitor electrode 126 and increase the aperture ratio of each pixel, the thickness d of the interlayer insulating film 136 is decreased, , And it is necessary to reduce the minimum width n of the light-shielding film necessary to prevent the minimum light leakage from the reverse tilt zone.

In practice, the thickness d, the diameter?, And the minimum width n have a limit value. The angle? Should be set to less than 65. in order to form the film in the connection hole 142 well, and should be set to 45. or more so that the diameter of the connection hole 142 is not too large.

After the connection hole 142 is formed, an orientation film 150 is formed on the interlayer insulating film 136 to perform rubbing treatment. Thereby, an active matrix substrate is obtained.

Next, the counter substrate is manufactured as follows. The counter substrate may be manufactured before the production of the active matrix substrate described above.

Referring again to FIGS. 17 and 18, a metal film made of Ta, Cr, Al, or the like is formed on the transparent insulating substrate 122 made of glass or the like by sputtering and patterned to form a light shielding layer 144 . Next, a light-sensitive color resist is applied to a portion of the substrate 122 on which the light-shielding layer 144 is not formed, exposed, and developed to form a color layer (color filter) 146 showing red, green, and blue colors do. As a result, each color layer 146 is surrounded by the light shielding layer 144. Next, on the light-shielding layer 144 and the color layer 146, for example, a counter electrode 148 made of ITO or the like is formed into a predetermined shape by sputtering. Next, an alignment film 150 is formed on the counter electrode 148 to perform a rubbing process. Thereby, the counter electrode is obtained.

The active matrix substrate and the counter substrate thus manufactured are laminated together by a known method so as to face the alignment film 150 with a predetermined gap (cell gap) therebetween. After the substrate is laminated, a liquid crystal material is injected into the gap by a known method to form the liquid crystal layer 112. [ Thus, a liquid crystal display device according to the present invention is obtained.

(Example 5)

19 is a plan view of one pixel of a liquid crystal display device according to still another embodiment of the present invention. FIG. 20 is a cross-sectional view of the liquid crystal display taken along the line A-A 'of FIG. 19, and FIG. 21 is a cross-sectional view of the liquid crystal display taken along the line B-B' of FIG.

Alignment direction D ₄ of the liquid crystal molecules (152a) in the liquid crystal display of the fourth embodiment shown in Figure 17 is the opposite to the orientation direction D _3. 19, each storage capacitor electrode 126 is located between adjacent pixel electrodes 140, and each gate signal line 104 crosses the center of each pixel electrode 140. [ Each elongated drain electrode 125 extends to an adjacent pixel electrode 140 and overlaps the storage capacitor electrode 126,

20, each connection hole 142 is formed on the storage capacitor electrode 126 under the elongated drain electrode 125 in the case of the liquid crystal display device of this embodiment. However, the center axis 160 of the connection hole 142 is offset from the center axis 156 of the storage capacitor electrode 126.

It is preferable that the center axis 160 of the connection hole 142 is offset from the central axis 156 of the storage capacitor electrode 126 in the alignment direction D ₄ of the liquid crystal molecules 152a. The distance between the central axis 160 and the central axis 156 is the same as that described in the fourth embodiment. The reverse tilt zone 154 is formed at a position where its central portion is offset from the central axis 160 of the connection hole 142 in the direction opposite to the alignment direction D ₄ of the liquid crystal molecules 152a. Thus, the generated reverse tilt zone is located on the storage capacitor electrode 126. Therefore, light leakage from the reverse tilt zone can be effectively prevented by the storage capacitor electrode 126. [ In the liquid crystal display device of this embodiment, the line width of the storage capacitor electrode 126 can be minimized and the high aperture ratio can be maintained.

(Example 6)

22 is a plan view of one pixel of a liquid crystal display device according to still another embodiment of the present invention. FIG. 23 is a cross-sectional view of the liquid crystal display taken along the line A-A 'in FIG. 22, and FIG. 24 is a cross-sectional view of the liquid crystal display taken along the line B-B' in FIG.

Alignment direction D ₄ of the liquid crystal molecules (152a) in the liquid crystal display of the fourth embodiment shown in Figure 17 is the opposite to the orientation direction D _3. As shown in Fig. 22, the storage capacitor electrode 126 is not formed, and each gate signal line 104 'is wider than the width of the gate signal line 104 shown in Fig. Each elongated drain electrode 125 extends to an adjacent pixel electrode 140.

23, in the case of the liquid crystal display device of this embodiment, the connection hole 142 is formed on the wide portion 125a of the elongated drain electrode 125. As shown in Fig. The center axis 160 of the connection hole 142 is offset from the center axis 156 of the shielding signal line by the wide portion 125a of the extended drain electrode 125. [

It is preferable that the central axis 160 of the connection hole 142 is offset from the central axis 156 of the shielding signal line in the alignment direction D ₄ of the liquid crystal molecules 152a. The distance between the center axis 160 and the center axis 156 is equal to the distance between the center axis 160 of the connection hole 142 and the center axis 156 of the storage capacitor electrode 126 described in Embodiment 4. [ The reverse tilt zone 154 is formed at a position where its central portion is offset from the central axis 160 of the connection hole 142 in the direction opposite to the alignment direction D ₄ of the liquid crystal molecules 152a. Thus, the generated reverse-tilt region is positioned on the light-shielding wide portion 125a of the elongated drain electrode 125. [ Therefore, light leakage from the reverse tilt region can be effectively prevented by the shielding wide portion 125a of the elongated drain electrode 125. [ In the liquid crystal display device of this embodiment, the line width of the light shielding wide portion 125a of the elongated drain electrode 125 can be minimized and the high aperture ratio can be maintained.

(Example 7)

25 is a plan view of one pixel of a liquid crystal display device according to still another embodiment of the present invention.

In this embodiment, a gate signal line 104 and a storage capacitor electrode 164 are formed on a transparent substrate (not shown). A source signal line 102, a storage capacitor electrode 126, an interlayer insulating film (not shown), and a pixel electrode (not shown) are formed on the gate insulating film, 140 are formed in the order described.

The light shielding drain electrode 124 of each TFT 106 is connected to the corresponding pixel electrode 140 through the connection hole 142a formed through the interlayer insulating film. Each light-shielding storage capacitor electrode 126 is connected to the corresponding pixel electrode 140 through a connection hole 142b formed through an interlayer insulating film.

Connection holes are offset to the alignment direction D ₄ of the liquid crystal molecules from the central axis (the central axis of the light shielding signal lines) of the drain electrode 124 of the TFT central axis (106) of a (142a). Thus, since the reverse-tilt zone generated due to the presence of the connection hole 142a is located on the drain electrode 124, it is possible to effectively prevent light leakage from such a reverse-tilt zone. Similarly, it is offset from the central axis of the central axis storage capacitor electrode 126 of the connection hole (142b) in the alignment direction D ₄ of the liquid crystal molecules. Thus, the reverse tilt zone generated by the presence of the connection hole 142b is located on the storage capacitor electrode 126, so that light leakage from such a reverse tilt zone can be effectively prevented.

In the fourth to seventh embodiments, various modifications of the present invention are possible. For example, the reverse tilt zone generated by the concave portion of the alignment film formed by inclining the inner wall of the connection hole has been described. The present invention can also be applied to a reverse tilt region generated by a concave portion of an alignment film formed by an electrode and a TFT. Embodiments 4 to 7 can be applied not only to a transparent liquid crystal display device but also to a reflective liquid crystal display device. In the case of a reflective liquid crystal display device, a light shielding film is formed on the substrate side for transmitting light.

The liquid crystal display device according to the present invention having a high aperture ratio is particularly useful for a relatively small liquid crystal display device used as a viewfinder and a projector of a video camera.

Those skilled in the art will recognize that many variations and modifications may be made without departing from the spirit and scope of the invention. Therefore, the present invention should not be limited to the above-described embodiments, but should be interpreted broadly in accordance with the matters described in the following claims.

Claims (14)

In a liquid crystal display device, A gate signal line, a source signal line intersecting the gate signal line, an interlayer insulating film formed on the gate signal line and the source signal line, and a pixel electrode formed on the interlayer insulating film, The first pixel electrode and the second pixel electrode adjacent to each other on both sides of the gate signal line partially overlap the gate signal line sandwiched by the first pixel electrode and the second pixel electrode, Wherein the first pixel electrode is located downstream of the pretilt angle direction of the liquid crystal molecules with respect to the gate signal line and the second pixel electrode is located upstream of the pretilt angle direction of the liquid crystal molecules, Wherein the overlap width of the first pixel electrode and the gate signal line is greater than the overlap width of the second pixel electrode and the gate signal line. The liquid crystal display device according to claim 1, wherein the liquid crystal display device is driven by a gate line inversion driving method. In a liquid crystal display device, A gate signal line, a source signal line intersecting the gate signal line, an interlayer insulating film formed on the gate signal line and the source signal line, and a pixel electrode formed on the interlayer insulating film, Third and fourth pixel electrodes adjacent to each other on both sides of the source signal line are partially overlapped with the source signal line sandwiched by the third pixel electrode and the fourth pixel electrode, The third pixel electrode is located downstream of the pretilt angle direction of the liquid crystal molecules with respect to the source signal line, the fourth pixel electrode is located upstream of the pretilt angular direction of the liquid crystal molecules, And the overlap width of the source signal lines is larger than the overlap width of the fourth pixel electrodes and the source signal lines. The liquid crystal display device according to claim 3, wherein the liquid crystal display device is driven by a source line inversion driving method. In a liquid crystal display device, A gate signal line, a source signal line intersecting the gate signal line, an interlayer insulating film formed on the gate signal line and the source signal line, and a pixel electrode formed on the interlayer insulating film, The first pixel electrode and the second pixel electrode adjacent to each other on both sides of the gate signal line partially overlap the gate signal line sandwiched by the first pixel electrode and the second pixel electrode, Wherein the first pixel electrode is located downstream of the pretilt angle direction of the liquid crystal molecules with respect to the gate signal line and the second pixel electrode is located upstream of the pretilt angle direction of the liquid crystal molecules, The overlap width of the gate signal lines is larger than the overlap width of the second pixel electrodes and the gate signal lines, Third and fourth pixel electrodes adjacent to each other on both sides of the source signal line are partially overlapped with the source signal line sandwiched by the third pixel electrode and the fourth pixel electrode, The third pixel electrode is located downstream of the pretilt angle direction of the liquid crystal molecules with respect to the source signal line, the fourth pixel electrode is located upstream of the pretilt angular direction of the liquid crystal molecules, And the overlap width of the source signal lines is larger than the overlap width of the fourth pixel electrodes and the source signal lines. The liquid crystal display device according to claim 5, wherein the liquid crystal display device is driven by a dot inversion driving method. In a liquid crystal display device, A gate signal line, a source signal line intersecting the gate signal line, an interlayer insulating film formed on the gate signal line and the source signal line, and a pixel electrode formed on the interlayer insulating film, Wherein each of the pixel electrodes has a first region and a second region which are adjacent to each other and have different alignment directions of liquid crystal molecules, The first region and the second region of each pixel electrode partially overlap the source signal line, The source signal line is located in the pretilt angular direction of the liquid crystal molecules in the first region, The source signal line is located in the pretilt angle direction upstream of the liquid crystal molecules in the second region, The overlap width of the second region and the source signal line is larger than the overlap width of the first region and the source signal line And a boundary portion between the first region and the second region is covered with a light shielding film crossing the source signal line. 8. The pixel electrode of claim 7, wherein the source signal line is substantially straight, and an edge of the first region of the pixel electrode overlapping the source signal line is connected to an edge of the second region of the pixel electrode overlapping the source signal line Is offset from the reference voltage. 8. The method of claim 7, wherein an end of a portion of the source signal lines overlapping the first region is offset from an end of a portion of the source signal lines overlapping the second region, The edge of the first region being aligned with the edge of the second region overlapping the source signal line. 8. The liquid crystal display device according to claim 7, wherein the liquid crystal display device is driven by a source line inversion driving method or a dot line inversion driving method. In a liquid crystal display device, A gate signal line, a source signal line intersecting the gate signal line, an interlayer insulating film formed on the gate signal line and the source signal line, a pixel electrode formed on the interlayer insulating film, and a connection hole formed through the interlayer insulating film And a drain electrode connected to the corresponding pixel electrode, Wherein each of the connection holes is formed on a shielding signal line located below a corresponding drain electrode, And the center axis of the connection hole is offset by a certain distance in the pretilt angle direction of the liquid crystal molecules from the central axis of the shielding signal line. 12. The liquid crystal display device according to claim 11, wherein the distance between the center axis of the connection hole and the center axis of the shielding signal line is within a range of about 0.5 to about 1.5 mu m. 12. The liquid crystal display device according to claim 11, wherein the gate electrodes of the respective switching elements are disposed in a deepening portion of a corresponding pixel electrode, and the shielding signal line is provided between pixel electrodes adjacent to the pixel electrode in a direction opposite to a pretilt angle direction of liquid crystal molecules And wherein the liquid crystal display device is disposed in the liquid crystal display device. The liquid crystal display according to claim 11, wherein the shielding signal line forms a gate electrode of each switching element, and the gate electrode is disposed between pixel electrodes adjacent to the pixel electrode in a direction opposite to a pretilt angle direction of liquid crystal molecules Wherein the liquid crystal display device is a liquid crystal display device.

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