JP2001281696A - Active matrix type liquid crystal display device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To suppress block separation caused by variation in electrostatic capacity between signal wiring and pixel electrodes. SOLUTION: A pixel electrode 62 is at the position bisecting both side edges, and is bent at the position of an auxiliary capacity wiring 63. Then, the part on the side of a TFT 55 from the auxiliary capacity wiring 63 is coated with a pixel electrode 62", while the part on the other side of the TFT 55 is coated with the pixel electrode 62. Thus, a coupling capacitance between the pixel electrode 62 and the source wiring 54 is reduced in this bent part. As a result, variation in the coupling capacitance between the pixel electrode 62 and the source wiring 54 in the bent part is reduced, when a misalignment occurs, and the block separation is suppressed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an active matrix type liquid crystal display device used for a liquid crystal television, a notebook personal computer or the like.

[0002]

2. Description of the Related Art FIGS. 13 and 14 are a plan view and a sectional view of a general active matrix type liquid crystal display device. The active matrix type liquid crystal display device is schematically constituted by a liquid crystal panel 1, a gate drive circuit 2, a source drive circuit 3, and a backlight 4.

Further, the liquid crystal panel 1 has an active matrix substrate 5, a counter substrate 6, a liquid crystal layer 7 interposed between the substrates 5, 6, and a deflecting plate (shown in FIG. )).

On the active matrix substrate 5, a plurality of scanning wirings (not shown) arranged in parallel, and a plurality of signal wirings arranged in parallel with the scanning wirings through an insulating film 8 at right angles. 9, a thin film transistor (TFT) 10 disposed near each intersection between the scanning wiring and the signal wiring 9, a plurality of pixel electrodes 11 disposed in a region surrounded by the scanning wiring and the signal wiring 9, and the like. Have been.

FIG. 15 is a plan view showing one pixel portion of the active matrix substrate 5. Pixel electrode 11
Is formed in the same layer as the signal wiring 9,
It is formed so as not to contact the signal wiring 9 at a predetermined distance. The TFT 10 is a three-terminal device, and the conduction of current between the drain electrode 13 and the source electrode 14 is controlled by a voltage applied to the gate electrode 12. Then, the gate electrode 12 is connected to the adjacent scanning line 15, the source electrode 14 is connected to the adjacent signal line 9, and
The drain electrode 13 is connected to the pixel electrode 11.

On the other hand, each pixel electrode 1 is
A color filter 16 is formed at a position corresponding to 1 in the order of arrangement of red, green, and blue. A black matrix 17 is formed between the color filters 16 and 16 as a light shielding film for preventing light from leaking from between the scanning wiring 15 and the signal wiring 9 and the pixel electrode 11. Further, a counter electrode 18 made of a transparent conductive material is formed on this upper layer. The gate drive circuit 2 and the source drive circuit 3 are connected to the terminals of the scanning wiring 15 and the terminals of the signal wiring 9 arranged around the liquid crystal panel 1, respectively.

Next, a method of driving the active matrix type liquid crystal display device having the above configuration will be described.

In the driving method of the active matrix type liquid crystal display device, when writing the pixel array in the n-th row, the scanning line 1 from the gate drive circuit 2 to the n-th row is used.
An ON signal (a potential at which the TFT 10 is turned on: Vgh) is input to 5n. At this time, an off signal (a potential at which the TFT 10 is turned off: Vgl) is input to the scanning lines other than the scanning line 15n. Therefore, only the TFT 10 in the n-th row is turned on. In this case, a source signal of a voltage to be charged to the pixels in the n-th row (the pixel electrode 11 and the liquid crystal layer 7) is supplied from the source drive circuit 3 to each signal line 9.

When the writing to the array of pixels in the n-th row is completed, an off signal is input to the scanning wiring 15n, while an on signal is input to the scanning wiring 15 (n + 1). By repeating the above operation, all the pixels are charged with an arbitrary voltage value. Since the transmittance of the liquid crystal layer 7 between the pixel electrode 11 and the counter electrode 18 changes depending on the voltage applied between the electrodes 11 and 18, the light from the backlight 4 is adjusted to display an arbitrary image. Is done.

By the way, a pixel electrode is provided on the interlayer insulating film, and the pixel electrode and the signal wiring are formed on different layers.
A structure in which a pixel electrode is overlaid on a signal line has also been proposed.
(JP-A-4-121712, etc.). FIG. 16 is a cross-sectional view of one pixel in an active matrix liquid crystal display device having a structure in which the pixel electrode is overlaid on a signal wiring. FIG. 17 is a plan view of the active matrix substrate shown in FIG. In such a configuration,
The pixel electrode 21 and the signal wiring 22 are formed in different layers, and the pixel electrode 21 and the signal wiring 22 are overlapped with each other with an interlayer insulating film 23 interposed therebetween.
Can be eliminated. Therefore, the area (aperture ratio) of the pixel electrode 21 can be increased, and the power consumption of the active matrix liquid crystal display device can be suppressed. 24 is an active matrix substrate,
25 is a TFT, 26 is a liquid crystal layer, 27 is a counter electrode, 28 is a counter substrate, 29 is a scanning line, 30 is a contact hole,
31 is an auxiliary capacitance electrode, and 32 is an auxiliary capacitance wiring.

However, as described above, the pixel electrode 21
In the case where the structure in which is overlapped with the signal wiring 22 is adopted, FIG.
As shown in FIG. 5, the capacitance Csd between the pixel electrode 21 and the signal wiring 22 is increased as compared with the conventional structure in which the pixel electrode 11 has a predetermined distance from the signal wiring 9. In that case,
With an increase in the capacitance Csd, the potential of the pixel is easily changed by the source signal, and a deterioration in display characteristics called shadowing occurs.

Hereinafter, this mechanism will be described using an equivalent circuit of the active matrix substrate 24 shown in FIG. That is, when the ON signal Vgh is input to the scanning line Gn and the TFT 23 is turned on, the voltage Vs1 of the signal line S1 is charged to the pixel electrode P1.

Next, when the off signal Vgl is input to the scanning line Gn and the TFT 23 is turned off, the signal line S1 is turned off.
Is supplied with a voltage Vs1 'to be written to the pixel electrode P2 of the next stage. In that case, the voltage of the pixel electrode P1 is the capacitance Cs
It changes under the influence of the voltage Vs1 'of the signal wiring S1 via d1. Assuming that the voltage of the pixel electrode P1 at that time is Vp1, Vp1 = Vs1− (Csd1 (Vs1−Vs1 ′) + Csd2 (Vs2−Vs2 ′)) / (Cp + Csd1 + Csd2) (1) Here, Cp is the capacitance of the pixel electrode (Cp = liquid crystal capacitance Clc + auxiliary electrode capacitance Ccs), and Csd1 is the signal line S1.
Csd2 is the capacitance between the signal line S2 and the pixel electrode P2, and Vs1, Vs
2 is the voltage of the signal wirings S1 and S2 when the scanning wiring Gn of the n-th column is in the on state, and Vs1 ′ and Vs2 ′ are the voltages of the scanning wiring G (n + 1) of the (n + 1) -th column. If there is a signal wiring S1,
This is the voltage of S2.

An active matrix type liquid crystal display device
In a gate line inversion drive (1H inversion drive) which is a general driving method, the polarity of a source signal is inverted for each gate line. Here, assuming that the adjacent gradations are the same, Vs = Vs1 = Vs2, Vs ′ = Vs1 ′ = Vs2 ′ (2) Therefore, from equations (1) and (2), Vp1 = Vs− (Csd1 + Csd2) / (Cp + Csd1 + Csd2) · (Vs−Vs ′) (3) Thus, in the 1H inversion drive, the amount of change in pixel potential is proportional to (Csd1 + Csd2). For this reason, shadowing appears remarkably with an increase in the capacitance Csd between the signal line S and the pixel electrode P.

On the other hand, dot inversion driving has been proposed as a driving method for suppressing a change in pixel potential due to the capacitance Csd between the signal line S and the pixel electrode P. In this dot inversion drive, the polarity of the source signal is inverted for each gate line, and a signal of the opposite polarity is also input to the source side for each source line.

In the case of the above-mentioned dot inversion driving, assuming that the adjacent gray scales are the same, Vs = Vs1 = −Vs2, Vs ′ = Vs1 ′ = − Vs2 ′ (4) From (1) and equation (4), Vp1 = Vs− (Csd1−Csd2) / (Cp + Csd1 + Csd2) · (Vs−Vs ′) (5) As described above, in the dot inversion drive, the amount of change in the pixel potential is proportional to the difference between the capacitance Csd1 and the capacitance Csd2. Therefore, the shadowing phenomenon can be greatly suppressed as compared with the case of 1H inversion driving, and the image quality of the liquid crystal display device can be improved. In particular, when the difference between the capacitance Csd1 and the capacitance Csd2 of the pixels adjacent to each other in the direction in which the scanning wiring 29 extends, the shadowing phenomenon can be significantly suppressed.

However, in that case, the following new problem occurs. That is, in the dot inversion drive, the transmittance difference due to the variation in the capacitance Csd between the signal line S and the pixel electrode P becomes large. That is, so-called block division in which the overlap width of S and the pixel electrode P is different in block units easily occurs.

For example, as shown in FIG. 19, consider a case where an alignment deviation dx occurs in the photolithography process of the pixel electrode P. In this case, the amount of overlap of the pixel electrode P with the signal line S1 increases, so that the capacitance Csd1 between the signal line S1 and the pixel electrode P increases, and conversely, the capacitance between the signal line S2 and the pixel electrode P. Csd2 decreases. FIG. 20 shows the misalignment dx in the photolithography process.
And the relationship between the capacitance Csd1 and the capacitance Csd2. As shown in FIG. 20, the difference between the capacitances Csd1 and Csd2 increases as the misalignment dx increases, and the amount of change in the pixel potential increases.

In order to solve such a problem, in an active matrix type liquid crystal display device having a structure in which the pixel electrode is overlapped on a signal wiring, a side edge of each of two pixel electrodes adjacent to each other with the signal wiring interposed therebetween. Has been proposed in which approximately 1/2 of each is completely overlapped on the signal wiring. 21 and 22 show a cross-sectional view and a plan view of a structure in which approximately の of each side edge of each adjacent pixel electrode is completely overlapped on the signal wiring. In this case, approximately one half of one side edge of the pixel electrode 45 is connected to the signal wiring 43 adjacent to one side.
Completely overlaps. Further, approximately one half of the other side edge of the pixel electrode 45 completely overlaps with the signal wiring 43 ′ adjacent to the other side. Therefore, Csd1 ≒ Csd2, and (Csd1−Csd2) in the above equation (5) decreases. further,
Since the adjacent pixel electrodes 45 ″ and 45 completely cover the signal wiring 43, even if an alignment shift occurs,
(Csd1-Csd2) hardly changes. Therefore, block separation due to shadowing as described above can be suppressed.

Reference numeral 41 denotes a TFT; 42, a scanning line;
Is an interlayer insulating film, 46 is a contact hole, 47 is an auxiliary capacitance electrode, and 48 is an auxiliary capacitance wiring.

[0021]

However, the conventional active matrix type liquid crystal display device shown in FIGS. 21 and 22 has the following problems. That is, as described above, the dot inversion driving of the active matrix type liquid crystal display device having a structure in which approximately 1/2 of the side edge of each of the adjacent pixel electrodes is completely overlapped on the signal wiring as shown in FIGS. Thereby, the shadowing phenomenon due to the coupling capacitance Csd between the signal wiring 43 and the pixel electrode 45 is suppressed, and the coupling capacitance Csd is suppressed.
Block separation due to the variation in the distance can be suppressed.

However, in the case of the above structure,
It is necessary to arrange the two pixel electrodes 45 ″ and 45 adjacent to each other on both sides of the signal wiring 43 so as to completely cover the signal wiring 43. Therefore, the signal wiring 43 is covered. At the point where the pixel electrodes 45 ″ and 45 are switched, the signal wiring 43 must be connected to the adjacent pixel electrode 4.
There are areas that cannot be covered with either 5 "or 45".
Therefore, due to misalignment between layers,
The coupling capacitance Csd between the surrounding pixel electrode 45 (45 ") and the signal wiring 43 in the above-mentioned region due to a change in the distance between the pixel electrodes 45" and 45, and, consequently, the pixel electrode 45 (45 " ) Greatly changes the coupling capacitance Csd of the portion of the signal wiring 43 covered with the pixel electrode 45 (45 ″).

For example, when the definition is 130 PPI to 200 P
In an active matrix liquid crystal display device having a high definition of PI or higher, or an active matrix liquid crystal display device in which an interlayer insulating film needs to be thinner due to its configuration, the above-described influence is increased, which is a problem.

Accordingly, an object of the present invention is to provide an active matrix type liquid crystal display device which can prevent deterioration in image quality due to coupling capacitance between a signal wiring and a pixel electrode and can suppress block separation due to the variation in coupling capacitance. Is to do.

[0025]

According to a first aspect of the present invention, a plurality of scanning lines formed on an insulating substrate, an auxiliary capacitance line disposed in parallel with the scanning lines, and A plurality of signal wirings intersecting the scanning wirings, a plurality of switching elements arranged in a matrix near each intersection of the scanning wirings and the signal wirings, and arranged in a matrix connected to output terminals of the switching elements; In the active matrix type liquid crystal display device having the pixel electrodes formed as described above, the pixel electrodes are formed such that both side edges along the signal wiring are bent to form overhang portions on both side portions. The wiring is covered in the width direction, and the auxiliary capacitance wiring is arranged so as to overlap the bent portion of the pixel electrode.

According to the above configuration, the pixel electrode is bent at both side edges along the signal wiring to form overhangs on both sides, and the overhangs cover the adjacent signal wiring in the width direction. . Therefore, the difference between the first capacitance between the pixel electrode and the signal wiring adjacent to one side and the second capacitance between the pixel electrode and the signal wiring adjacent to the other side is reduced. By performing the dot inversion drive, the shadowing phenomenon can be greatly suppressed.

At this time, an auxiliary capacitance line is arranged so as to overlap the bent portion of the pixel electrode. Therefore, the capacitance between the bent portion of the pixel electrode and the signal wiring is reduced. As a result, the change in capacitance between the signal wiring and the bent portion of the pixel electrode due to misalignment between layers is greatly reduced, and block separation that occurs when performing a photolithography process in block units is suppressed. Is done.

According to a second aspect of the present invention, a plurality of scanning lines formed on an insulating substrate, an auxiliary capacitance line disposed in parallel with the scanning lines, a plurality of signal lines intersecting the scanning lines, A plurality of switching elements arranged in a matrix near each intersection of the scanning wiring and the signal wiring,
In an active matrix liquid crystal display device having pixel electrodes connected to the output terminals of each switching element and arranged in a matrix, the pixel electrodes are formed such that both side edges along the signal wiring are bent and project over both side portions. Is formed, and the adjacent signal wiring is covered in the width direction by the both overhangs, and the auxiliary capacitance wiring has an electrode portion extending to a position overlapping the bent portion of the pixel electrode. And

According to the above structure, the pixel electrode is bent at both side edges along the signal wiring to form overhangs on both sides, and the adjacent overhanging signal wiring is covered in the width direction. . Therefore, as in the case of the first aspect, by performing the dot inversion drive, the shadowing phenomenon can be largely suppressed.

At this time, an electrode portion extending from the auxiliary capacitance wiring is arranged so as to overlap the bent portion of the pixel electrode. Therefore, similarly to the case of the first aspect, the capacitance between the bent portion of the pixel electrode and the signal wiring is reduced, and the variation in the capacitance between the pixel electrode and the signal wiring is reduced. The block separation is suppressed.

According to a third aspect of the present invention, a plurality of scanning lines formed on an insulating substrate, an auxiliary capacitance line arranged in parallel with the scanning lines, a plurality of signal lines intersecting the scanning lines, A plurality of switching elements arranged in a matrix near each intersection of the scanning wiring and the signal wiring,
In an active matrix liquid crystal display device having pixel electrodes connected to output terminals of respective switching elements and arranged in a matrix, the signal lines are bent near first and second pixel electrodes adjacent to each other. One is covered in the width direction by the first pixel electrode with the bent portion as a boundary, and the other is covered in the width direction by the second pixel electrode with the bend as a boundary.
It is characterized in that it is arranged so as to overlap the bent portion of the signal wiring.

According to the above configuration, the signal wiring is bent near the first and second pixel electrodes adjacent to each other, and one of the signal wirings is covered in the width direction by the first pixel electrode with the bent portion as a boundary, The other is covered in the width direction by the second pixel electrode. Therefore, focusing on one pixel electrode, the first capacitance between the pixel electrode and the signal wiring adjacent to one side and the first capacitance between the pixel electrode and the signal wiring adjacent to the other side are considered. (2) The difference from the capacitance is reduced, and the shadowing phenomenon is significantly suppressed by performing the dot inversion drive.

At this time, an auxiliary capacitance line is arranged so as to overlap the bent portion of the signal line. Therefore, the capacitance between the bent portion of the signal wiring and the pixel electrode is reduced. As a result, the change in the capacitance between the bent portion of the signal wiring and the pixel electrode due to the misalignment between the layers is significantly reduced, and the block separation is suppressed.

According to a fourth aspect of the present invention, there are provided a plurality of scanning lines formed on an insulating substrate, an auxiliary capacitance line disposed in parallel with the scanning lines, a plurality of signal lines intersecting the scanning lines, A plurality of switching elements arranged in a matrix near each intersection of the scanning wiring and the signal wiring,
In an active matrix liquid crystal display device having pixel electrodes connected to output terminals of respective switching elements and arranged in a matrix, the signal lines are bent near first and second pixel electrodes adjacent to each other. One is covered in the width direction by the first pixel electrode with the bent portion as a boundary, and the other is covered in the width direction by the second pixel electrode with the bend as a boundary.
It is characterized by having an electrode portion extending to a position overlapping the bent portion of the signal wiring.

According to the above configuration, the signal wiring is bent near the first and second pixel electrodes adjacent to each other, and one of the signal wirings is covered in the width direction by the first pixel electrode with the bent portion as a boundary, The other is covered in the width direction by the second pixel electrode. Therefore, as in the case of the third aspect, by performing the dot inversion drive, the shadowing phenomenon can be greatly suppressed.

At this time, an electrode portion extending from the auxiliary capacitance line is arranged so as to overlap the bent portion of the signal line. Therefore, as in the case of the third aspect, the capacitance between the pixel electrode and the bent portion of the signal line is reduced, and the capacitance between the pixel electrode and the signal line is varied. The block separation is suppressed.

The active matrix type liquid crystal display device according to the first to fourth aspects of the present invention preferably includes a light-shielding film disposed on the insulating substrate at a position between mutually adjacent pixel electrodes.

Generally, the alignment accuracy between the insulating substrate on which the pixel electrode is formed and the opposing substrate facing the insulating substrate is about ± 5 μm, whereas the alignment accuracy between the layers on the insulating substrate is about ± 5 μm. Is ± 1 μm or less. According to the configuration, the light-shielding film is disposed at a position between the pixel electrodes adjacent to each other on the insulating substrate. Therefore, the width of the light-shielding film is formed narrower than that of the black matrix arranged on the counter substrate side, and the black matrix is eliminated, thereby improving the aperture ratio.

Further, since the area of the black matrix arranged on the counter substrate side is reduced, the bonding margin between the insulating substrate and the counter substrate is widened.

Further, in the active matrix liquid crystal display device according to the first to fourth inventions, the light shielding film is
It is desirable to electrically connect to the above-mentioned auxiliary capacitance wiring or scanning wiring.

According to the above arrangement, the electric field shielding effect provided by the light shielding film disposed near the signal wiring causes
A part of the line of electric force from the signal wiring is terminated. Therefore, the first capacitance between the pixel electrode and the signal wiring adjacent to one side and the second capacitance between the pixel electrode and the signal wiring adjacent to the other side are reduced. As a result, the shadowing phenomenon caused by the difference between the first capacitance and the second capacitance is further suppressed, and the block division is further reduced.

[0042]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described in detail with reference to the illustrated embodiments. <First Embodiment> FIG. 1 is a plan view of an active matrix substrate in an active matrix type liquid crystal display device of the present embodiment. FIG. 2 is a cross-sectional view of the active matrix type liquid crystal display device taken along the line AA ′ of FIG. FIG. 3 is a cross-sectional view of the active matrix type liquid crystal display device taken along line BB ′ of FIG.

The active matrix substrate has the following configuration. That is, in FIGS. 1 to 3, a plurality of gate wirings (scanning wirings) 52 made of metal such as Al and Ta are arranged in parallel on an insulating substrate 51 serving as the active matrix substrate made of glass. The thickness of the gate wiring 52 is 2000 to 5000 degrees. Further, a plurality of source wirings 54, 54 'made of a metal such as Al, Ta or the like are arranged in the upper layer, intersecting the gate wiring 52 via a gate insulating film 53 made of SiNx or the like. The thickness of the gate insulating film 53 is 2,000 to 4
000 °, and the relative dielectric constant is about 3 to 8. The thickness of the source wirings 54 and 54 'is 1000 to 500.
0 °.

The gate wiring 52 and the source wirings 54, 5
In the vicinity of each intersection with 4 ′, amorphous silicon T
FT55 is arranged. Amorphous silicon TF
T55 is configured by stacking a gate electrode 56, a gate insulating film 53, an amorphous semiconductor layer 57, an impurity-added semiconductor layer 58, a source electrode 59, and a drain electrode 60. Gate electrode 56 is made of the same material as gate wiring 52. The source electrode 59 and the drain electrode 60 are made of the same material as the source wirings 54 and 54 '. The amorphous semiconductor layer 57 is made of amorphous silicon formed by CVD (Chemical Vapor Deposition), and has a thickness of about 500 to 2000 degrees.
The gate electrode 56 is connected to the adjacent gate wiring 52, and the source electrode 59 is connected to the adjacent source wiring 54.

An auxiliary capacitance line 63 is formed in the same layer as the gate line 52 (that is, on the insulating substrate 51), and the drain electrode 60 extends over the auxiliary capacitance line 63 via the gate insulating film 53. And the drain electrode 60
Form an auxiliary capacitance electrode 64. The interlayer insulating film 61 is made of an organic material or an inorganic material, has a thickness of 1 μm to 4 μm, and a relative dielectric constant of about 2 to 4. Then, the auxiliary capacitance electrode 64 in the interlayer insulating film 61
Is provided with a contact hole 65, and the drain electrode 60 is connected to the pixel electrode 62 by the contact hole 65 via the auxiliary capacitance electrode 64.

In the present embodiment, the auxiliary capacitance line 63 is formed by connecting the pixel electrode 62 to the TFT 55 side and the TFT 55 side.
It is arranged at a position that bisects the side. Then, the position of the auxiliary capacitance line 63 in the pixel electrode 62
Approximately の on the 55 side is the source wiring 5 adjacent on one side.
4 ′ with an interlayer insulating film 61 interposed therebetween. On the other hand, TF is larger than the position of the auxiliary capacitance line 63 in the pixel electrode 62.
Approximately の of the side opposite to T55 overlaps with the source wiring 54 adjacent to the other side via the interlayer insulating film 61.
That is, both side edges of the pixel electrode 62 are
It is bent at the position.

On the other hand, the counter substrate has the following configuration. That is, the color filters 67 are arranged on the insulating substrate 66 made of glass as the opposite substrate at positions corresponding to the respective pixel electrodes 62, 62 ', and 62 "in the order of red, green, and blue arrangement. , Each of the color filters 67,
A black matrix 68, which is a light-shielding film for preventing light from leaking between the adjacent pixel electrodes 62 'and 62 ", is disposed between the adjacent pixel electrodes 62' and 62". Furthermore, a counter electrode 69 made of a transparent conductive material is provided on the black matrix 68. It is arranged.

Then, the active matrix substrate 5
1 and the opposing substrate 66 are arranged at predetermined intervals with the pixel electrodes 62, 62 ', 62 "side and the opposing electrode 69 side facing each other, and the liquid crystal layer 70 is sandwiched between the two substrates 51, 66 with a sealing material. The active matrix type liquid crystal display device is configured by being enclosed.

As described above, in the present embodiment, the pixel electrode 62 is recessed along the contact hole 65 on the auxiliary capacitance line 63 and the auxiliary capacitance electrode 64 is formed.
(Drain electrode 60). Paying attention to the source wiring 54 on the left side in FIG.
In the portion on the fifth side, the pixel electrode 62 ″ located on the left side in FIG. 1 with respect to the source wiring 54 covers the source wiring 54.
In the portion on the 55 side, the pixel electrode 62 located on the right side in FIG. 1 with respect to the source wiring 54 covers the source wiring 54. The same applies to the source wiring 54 'on the right side in FIG.

That is, both side edges of the pixel electrode 62 are
A position bisected in the direction in which the source wiring 54 extends,
Further, it is bent at a position on the auxiliary capacitance wiring 63.

As shown in FIG.
8 is not disposed at such a position as to bisect the pixel electrode 45 into the TFT 41 side and the anti-TFT 41 side.
The bent portion of the pixel electrode 45 located at a position bisecting both side edges does not exist at the position of the auxiliary capacitance line 48. Therefore, the coupling capacitance Csd at the bent portion where the signal wiring 43 is not covered by the adjacent pixel electrodes 45 "and 45 greatly fluctuates due to the misalignment between the layers. The same applies to the case where the position of the bent portion is not at a position bisected in the extending direction of the source line 54. The point is that the auxiliary capacitance line is not arranged so as to overlap the bent portion of the pixel electrode. The fluctuation of the coupling capacitance Csd of the bent portion due to the misalignment is large.

On the other hand, in the present embodiment,
The auxiliary capacitance line 63 is arranged so as to divide the pixel electrode 62 into the TFT 55 side and the anti-TFT 55 side.
Therefore, the bent portion provided at a position bisecting both side edges of the pixel electrode 62 is located on the auxiliary capacitance wiring 63. Therefore, since the source wirings 54, 54 'and the auxiliary capacitance wiring 63 form a coupling capacitance, a part of the electric flux lines from the source wirings 54, 54' is terminated on the auxiliary capacitance wiring 63 side. The coupling capacitance Csd between the pixel electrode 62 and the source lines 54 and 54 'at the bent portion is reduced.

Therefore, even if an alignment shift occurs between the layers, the source line 5 is connected between the adjacent pixel electrodes 62 and 62 ″.
4 is not covered with the source wiring 54 in the bent portion.
And the change in the coupling capacitance Csd is small. as a result,
Coupling capacitance C between source line 54 and pixel electrode 62
The amount of change in sd1 and the coupling capacitance Csd2 between the source line 54 'and the pixel electrode 62 is greatly reduced, and the above-described block separation can be suppressed.

That is, according to the present embodiment, it is possible to suppress the block division due to the variation of the coupling capacitance Csd between the source lines 54 and 54 'and the pixel electrode 62.

<Second Embodiment> In the first embodiment, the auxiliary capacitance line 63 is connected to the pixel electrode 62 by T
It is arranged at a position where it is equally divided into the FT 55 side and the anti-TFT 55 side, that is, at the center of the pixel electrode 62. However, for reasons such as improvement of aperture ratio and improvement of manufacturing yield,
In many cases, the auxiliary capacitance wiring cannot be arranged at the center of the pixel electrode. The present embodiment addresses such a case.

FIG. 4 is a plan view of an active matrix substrate in the active matrix type liquid crystal display device of the present embodiment. FIG. 5 is a cross-sectional view of the active matrix type liquid crystal display device taken along the line CC ′ in FIG. FIG. 6 is a cross-sectional view of the active matrix type liquid crystal display device taken along the line DD ′ in FIG.

4 to 6, an active matrix substrate 71, a gate wiring 72, a gate insulating film 73, a source wiring 74, a TFT 75, an interlayer insulating film 81, a pixel electrode 82, a counter substrate 86, a color filter 87, and a black matrix 8 are shown.
8, the counter electrode 89 and the liquid crystal layer 90 are the same as those of the active matrix substrate 5 in the first embodiment shown in FIGS.
1, gate wiring 52, gate insulating film 53, source wiring 54,
54 ', TFT 55, interlayer insulating film 61, pixel electrode 62, counter substrate 66, color filter 67, black matrix 6
8, having the same configuration as the counter electrode 69 and the liquid crystal layer 70,
Works similarly.

Auxiliary capacitance line 83 in the present embodiment
Are arranged in parallel with the gate wiring 72 closer to the TFT 75 than the center of the pixel electrode 82. Then, the drain electrode 80 of the TFT 75 is extended to above the auxiliary capacitance wiring 83,
The storage capacitor electrode 84 is formed by the end of the drain electrode 80.
Is formed. Further, the auxiliary capacitance electrode 84 is connected to the pixel electrode 82 at the position of the contact hole 85.

Further, the auxiliary capacitance wiring 83 is provided with an electrode portion 91 extending below the source wiring 74 to the center of the pixel electrode 82. In this way, as shown in FIG. 4, the bent portion of the pixel electrode 82 provided at a position that bisects both side edges of the pixel electrode 82 is present on the electrode portion 91 having the same potential as the auxiliary capacitance wiring 83. .

Therefore, according to the present embodiment, even when the auxiliary capacitance line 83 cannot be arranged at the center of the pixel electrode 82, the case where the bent portion of the pixel electrode 82 exists on the auxiliary capacitance line 83 It can function similarly. That is, the source wire 74 and the electrode portion 9 at the bent portion
1 forms a coupling capacitance. As a result, the coupling capacitance Csd between the pixel electrode 82 and the source line 74 at the bent portion can be reduced.

In this case, if the pixel electrode 82 is bent on the auxiliary capacitance wiring 83, the bent position is not located at the center of the pixel electrode 82, so that Csd1 ≠ Csd2
And the value of (Csd1-Csd2) in the above equation (5) increases. Therefore, even if the dot inversion drive is adopted, the shadowing phenomenon due to the coupling capacitance Csd between the pixel electrode 82 and the source wiring 74 is likely to occur.

<Third Embodiment> FIG. 7 is a plan view of an active matrix substrate in an active matrix type liquid crystal display device of the present embodiment. FIG. 8 is a cross-sectional view of the active matrix type liquid crystal display device shown in FIG.
It is arrow sectional drawing corresponding to E '. FIG. 9 is a sectional view of the active matrix type liquid crystal display device shown in FIG.
It is arrow sectional drawing corresponding to -F '.

7 to 9, an active matrix substrate 101, a gate wiring 102, a gate insulating film 103,
TFT 105, interlayer insulating film 106, auxiliary capacitance wiring 108,
Auxiliary capacitance electrode 109, contact hole 110, counter substrate 111, color filter 112, black matrix 11
3, the counter electrode 114 and the liquid crystal layer 115 are shown in FIGS.
The active matrix substrate 51, the gate wiring 52, the gate insulating film 53, the TFT 55,
An interlayer insulating film 61, an auxiliary capacitance line 63, an auxiliary capacitance electrode 64,
Contact hole 65, counter substrate 66, color filter 6
7, black matrix 68, counter electrode 69 and liquid crystal layer 7
0 has the same configuration and functions similarly.

The pixel electrode 107 in this embodiment is
The two side edges are not bent as in the first embodiment but are formed in a straight line, and are formed in a rectangular shape. On the other hand, the source wiring 104 connects the pixel electrode 107 to the TFT 10
It is bent at the position of the auxiliary capacitance wiring 108 which is arranged at a position bisected on the 5th side and the TFT 105 side. In addition, approximately の of the source wiring 104 on the TFT 105 side with respect to the position of the auxiliary capacitance wiring 108 overlaps the pixel electrode 107 ′ located on one side via the interlayer insulating film 106. On the other hand, approximately 1/1 / the opposite side of the TFT 105 from the position of the auxiliary capacitance line 108 in the source line 104.
2 overlaps the pixel electrode 107 located on the other side via the interlayer insulating film 106.

That is, in this embodiment, the source wiring 104 is bent instead of bending both side edges of the pixel electrode as in the first embodiment. By doing so, as in the case of the first embodiment, the pixel electrode 107 and the source line 1 at the bent portion are formed.
04 can be reduced. Therefore, it is possible to suppress the above-described block separation caused by misalignment between layers.

Further, according to the present embodiment, the pixel electrode 107 can be formed in a rectangular shape as in the conventional active matrix type liquid crystal display device shown in FIGS. Therefore, the formation of the color filter 112 and the black matrix 113 is facilitated.

In this embodiment, the storage capacitor wiring 108 is connected to the pixel electrode 107 by a distance from the TFT 105 to the TFT 105 side.
It is arranged at a position bisecting the FT 105 side. However, when the auxiliary capacitance line cannot be arranged at the center of the pixel electrode 107, as in the second embodiment, the auxiliary capacitance line extends under each source line 104 to the bent portion of the source line 104. An electrode portion may be provided so that the bent portion of the source wiring 104 is present on the electrode portion having the same potential as the auxiliary capacitance wiring.

<Fourth Embodiment> FIG. 10 is a plan view of an active matrix substrate in an active matrix type liquid crystal display device of the present embodiment. FIG. 11 is a cross-sectional view of the active matrix type liquid crystal display device taken along the line GG ′ of FIG. FIG.
FIG. 11 is a cross-sectional view of the above active matrix liquid crystal display device, taken along the line HH ′ in FIG. 10.

10 to 12, an active matrix substrate 121, a gate wiring 122, a gate insulating film 12 are shown.
3, source wiring 124, TFT 125, interlayer insulating film 126,
Pixel electrode 127, auxiliary capacitance electrode 129, contact hole 130, counter substrate 131, counter electrode 134 and liquid crystal layer 1
Reference numeral 35 denotes an insulating substrate 51, a gate wiring 52, a gate insulating film 53, source wirings 54 and 54 ', a TFT 55, an interlayer insulating film 61, and a pixel electrode 6 in the first embodiment shown in FIGS.
2. It has the same configuration as the auxiliary capacitance electrode 64, the contact hole 65, the counter substrate 66, the counter electrode 69, and the liquid crystal layer 70, and functions similarly.

In the present embodiment, a light-shielding film 136 made of the same material as that of the gate wiring 122 is disposed in the same layer as the gate wiring 122 so as to shield light between the adjacent pixel electrodes 127. Therefore, the counter substrate 13
No need to dispose the black matrix 133 at a position between adjacent pixel electrodes 127 on the
It may be formed only on the FT 125.

Generally, the alignment accuracy between the active matrix substrate 121 and the counter substrate 131 is ± 5 μm.
m. On the other hand, the alignment accuracy between the layers of the active matrix substrate 121 is ± 1 μm or less. Therefore, the active matrix substrate 12
By disposing the light shielding film 136 on one side, the light shielding film 1
36 can be made narrower than the black matrix 133, and the black matrix 133 can be omitted. As a result, the area of the color filter 132 can be increased and the aperture ratio can be improved.

Further, since the area of the black matrix 133 disposed on the counter substrate 131 side is reduced, the bonding margin between the active matrix substrate 121 and the counter substrate 131 can be increased.

The light shielding film 136 is connected to the auxiliary capacitance wiring 128. Therefore, the coupling capacitance Csd between the source line 124 and the pixel electrode 127 is reduced by the electric field shielding effect of the light shielding film 136,
The shadowing phenomenon caused by the coupling capacitance Csd can be further suppressed. Further, since the absolute amount of the coupling capacitance Csd is reduced, the amount of change in the coupling capacitance Csd due to misalignment between layers is also reduced, and the block separation is further suppressed. here,
The light-shielding film 136 may be connected to the gate wiring 122 or may not be connected to the auxiliary capacitance wiring 128 or the gate wiring 122.

In this embodiment, the arrangement of the light-shielding film 136 and the deletion of the black matrix 133 due to the arrangement are applied to the first embodiment.
The present invention may be applied to the second and third embodiments without any problem. In each of the above embodiments, the pixel electrode 6
The bent portions of 2, 82, 127 and the bent portion of the source wiring 104 are provided at the centers of the respective pixel electrodes 62, 82, 107, 127. However, in order to suppress the shadowing phenomenon, it is not necessary to provide the bent portion exactly at the center of the pixel electrode. Therefore, the present invention does not limit the position of the bent portion provided in the pixel electrode or the source wiring to only the center of each pixel electrode.

Further, according to the present invention, to the extent that the same effects as in the above-described embodiments can be obtained, even if there is a portion that is not slightly covered in the width direction of the source wiring (signal wiring) on both sides of the pixel electrode. No problem.

[0076]

As is clear from the above description, in the active matrix type liquid crystal display device of the first invention, both sides of the pixel electrode are bent to form an overhang portion, and the adjacent overhang portion connects adjacent signal lines. Because it covers in the width direction,
A first portion between the pixel electrode and a signal line adjacent to one side is provided.
The difference between the capacitance and the second capacitance between the pixel electrode and the signal wiring adjacent to the other side can be reduced. Therefore, by performing the dot inversion drive, the shadowing phenomenon can be largely suppressed.

Further, since the auxiliary capacitance wiring arranged in parallel with the scanning wiring is arranged so as to overlap with the bent portion of the pixel electrode, the capacitance between the bent portion of the pixel electrode and the signal wiring is reduced. it can. Therefore, a change in capacitance between the bent portion of the pixel electrode and the signal wiring due to a misalignment between layers can be significantly reduced, and the amount of the block generated when performing the photolithography process in blocks can be reduced. This can be suppressed. That is, the block separation due to the variation in the capacitance can be suppressed.

In the active matrix type liquid crystal display device according to the second aspect of the present invention, both sides of the pixel electrode are bent to form an overhang, and the adjacent signal wiring is covered in the width direction by the both overhangs. As in the case of the first aspect, by performing the dot inversion drive, the shadowing phenomenon can be largely suppressed.

Further, since the auxiliary capacitance wiring disposed in parallel with the scanning wiring has an electrode portion extending to a position overlapping the bent portion of the pixel electrode, the auxiliary capacitance wiring is provided between the signal wiring at the bent portion of the pixel electrode. Can be reduced. Therefore, similarly to the case of the first aspect, the block separation caused by the misalignment between the layers can be suppressed.

Further, in the active matrix type liquid crystal display device according to the third aspect of the present invention, the signal wirings located near the first and second pixel electrodes adjacent to each other are bent, and one of the first and second pixel electrodes is set at the bent portion as a boundary. Since it is covered in the width direction by the pixel electrode, and the other is covered by the second pixel electrode in the width direction with the above-mentioned bend as a boundary, when attention is paid to one pixel electrode, it is adjacent to the pixel electrode on one side. The difference between the first capacitance between the signal line and the second capacitance between the pixel electrode and the signal line adjacent to the other side can be reduced. Therefore, by performing the dot inversion drive,
The shadowing phenomenon can be greatly suppressed.

Further, since the auxiliary capacitance wiring arranged in parallel with the scanning wiring is arranged so as to overlap the bent portion of the signal wiring, the capacitance between the bent portion of the signal wiring and the pixel electrode can be reduced. . Therefore, a change in capacitance between the pixel electrode and the bent portion of the signal wiring due to misalignment between layers can be significantly suppressed,
Block separation in performing the photolithography process in block units can be suppressed.

Further, in the active matrix type liquid crystal display device according to the fourth aspect of the present invention, the signal lines located near the first and second pixel electrodes adjacent to each other are bent, and one of the first pixel and the second pixel electrode is bounded by the bent portion. Since the electrode is covered in the width direction by the electrode and the other is covered by the second pixel electrode in the width direction at the boundary, the dot inversion driving is performed in the same manner as in the third aspect of the invention. The wing phenomenon can be largely suppressed.

Further, since the auxiliary capacitance line arranged in parallel with the scanning line has an electrode portion extending to a position overlapping with the bent portion of the signal line, the auxiliary capacitance line is provided between the pixel electrode and the bent portion of the signal line. Can be reduced. Therefore, similarly to the case of the third aspect, the block separation caused by the misalignment between the layers can be suppressed.

In the active matrix type liquid crystal display device according to the first to fourth aspects of the present invention, if a light-shielding film is arranged at a position between the pixel electrodes adjacent to each other on the insulating substrate, Since the alignment accuracy between the layers is smaller than the alignment accuracy between the insulating substrate and the counter substrate, the width of the light-shielding film can be narrower than the width of the black matrix arranged on the counter substrate side. Therefore, the aperture ratio can be improved in combination with the fact that the black matrix can be eliminated.

Further, since the area of the black matrix arranged on the counter substrate side is reduced, the bonding margin between the insulating substrate and the counter substrate can be increased.

Further, in the active matrix liquid crystal display device according to the first to fourth inventions, the light shielding film is
When electrically connected to the auxiliary capacitance wiring or the scanning wiring, the first electrostatic charge between the pixel electrode and the signal wiring adjacent to one side is formed by the electric field shielding effect of the light shielding film arranged near the signal wiring. The capacitance and the second capacitance between the pixel electrode and the signal wiring adjacent to the other side can be reduced. Therefore, the shadowing phenomenon caused by the difference between the first capacitance and the second capacitance can be further suppressed, and the block division can be further reduced.

[Brief description of the drawings]

FIG. 1 is a plan view of an active matrix substrate in an active matrix type liquid crystal display device of the present invention.

FIG. 2 is a sectional view taken along the line AA ′ in FIG.

FIG. 3 is a sectional view taken along the line BB ′ in FIG. 1;

FIG. 4 is a plan view of an active matrix substrate different from FIG.

FIG. 5 is a sectional view taken along the line CC ′ in FIG. 4;

FIG. 6 is a sectional view taken along the line DD ′ in FIG. 4;

FIG. 7 is a plan view of an active matrix substrate different from FIGS. 1 and 4;

FIG. 8 is a sectional view taken along the line EE ′ in FIG. 7;

FIG. 9 is a sectional view taken along the line FF ′ in FIG. 7;

FIG. 10 is a plan view of an active matrix substrate different from FIGS. 1, 4 and 7;

11 is a sectional view taken along the line GG ′ in FIG.

12 is a sectional view taken along the line HH ′ in FIG.

FIG. 13 is a plan view of a general active matrix liquid crystal display device.

14 is a cross-sectional view of one pixel portion of the active matrix liquid crystal display device shown in FIG.

15 is a plan view of one pixel portion of the active matrix liquid crystal display device shown in FIG.

FIG. 16 is a cross-sectional view of a conventional active matrix liquid crystal display device in which a pixel electrode is overlaid on a signal line.

17 is a plan view of the active matrix substrate in FIG.

18 is an equivalent circuit diagram of the active matrix substrate shown in FIG.

FIG. 19 is an explanatory diagram of misalignment of a pixel electrode.

FIG. 20 shows misalignment of pixel electrode and pixel electrode /
FIG. 6 is a diagram illustrating a relationship between capacitance and adjacent signal wiring.

FIG. 21 is a cross-sectional view of a conventional active matrix liquid crystal display device in which approximately １ of each side edge of each adjacent pixel electrode is overlapped on a signal wiring.

FIG. 22 is a plan view of the active matrix substrate in FIG. 21.

[Explanation of symbols]

51, 71, 101, 121 ... active matrix substrate, 52, 72, 102, 122 ... gate wiring (scanning wiring), 54, 54 ', 74, 104, 124 ... source wiring (signal wiring), 55, 75, 105 , 125 ... TFT, 60, 80 ... drain electrode, 61, 81, 106, 126 ... interlayer insulating film, 62, 62 ', 62 ", 82, 107, 127 ... pixel electrode, 63, 83, 108, 128 ... auxiliary Capacitance wiring, 64, 84, 109, 129: auxiliary capacitance electrode, 65, 85, 110, 130: contact hole, 66, 86, 111, 131: opposing substrate, 67, 87, 112, 132: color filter, 68, 88, 113, 133: black matrix; 69, 89, 114, 134: counter electrode; 70, 90, 115, 135: liquid crystal layer; 91: electrode section; 136: light shielding film.

 ──────────────────────────────────────────────────続 き Continued on the front page F-term (reference) 2H092 JA26 JB05 JB23 JB32 JB52 JB56 JB64 JB66 JB69 KB25 MA14 MA16 NA07 NA23 PA08 PA09 5C094 AA02 AA12 BA03 BA43 CA19 CA24 DA14 DA15 EA04 EA07 EA10 EB03 EB03 FB03 DD02 EE03 EE04 GG02 GG15 GG24 GG25 GG44 NN04 NN46 NN72 NN73

Claims (6)

[Claims] A plurality of scanning lines formed on an insulating substrate; an auxiliary capacitance line disposed in parallel with the scanning lines;
A plurality of signal wirings that intersect the scanning wirings, a plurality of switching elements arranged in a matrix near each intersection of the scanning wirings and the signal wirings, and a matrix connected to output terminals of the switching elements. In the active matrix type liquid crystal display device having the arranged pixel electrodes, the pixel electrodes are formed such that both side edges along the signal wiring are bent to form overhanging portions on both side portions, and the two overhanging portions are adjacent to each other. An active matrix liquid crystal display device, wherein a signal wiring is covered in a width direction, and the auxiliary capacitance wiring is arranged so as to overlap a bent portion of the pixel electrode. A plurality of scanning lines formed on the insulating substrate; an auxiliary capacitance line disposed in parallel with the scanning lines;
A plurality of signal wirings that intersect the scanning wirings, a plurality of switching elements arranged in a matrix near each intersection of the scanning wirings and the signal wirings, and a matrix connected to output terminals of the switching elements. In the active matrix type liquid crystal display device having the arranged pixel electrodes, the pixel electrodes are formed such that both side edges along the signal wiring are bent to form overhanging portions on both side portions, and the two overhanging portions are adjacent to each other. An active matrix liquid crystal display device, wherein a signal wiring is covered in a width direction, and the auxiliary capacitance wiring has an electrode portion extending to a position overlapping with a bent portion of the pixel electrode. 3. A plurality of scanning lines formed on an insulating substrate; an auxiliary capacitance line disposed in parallel with the scanning lines;
A plurality of signal wirings that intersect the scanning wirings, a plurality of switching elements arranged in a matrix near each intersection of the scanning wirings and the signal wirings, and a matrix connected to output terminals of the switching elements. In an active matrix type liquid crystal display device having a pixel electrode disposed, the signal wiring is bent near first and second pixel electrodes adjacent to each other, and one of the signal wirings is bounded by the bent portion as the first line.
The other is covered in the width direction by the pixel electrode, and the other is covered in the width direction by the second pixel electrode with the above-mentioned bend as a boundary, and the above-mentioned auxiliary capacitance wiring is arranged so as to overlap the bent part of the above-mentioned signal wiring An active matrix type liquid crystal display device characterized by the above-mentioned. 4. A plurality of scanning lines formed on an insulating substrate, an auxiliary capacitance line disposed in parallel with the scanning lines,
A plurality of signal wirings that intersect the scanning wirings, a plurality of switching elements arranged in a matrix near each intersection of the scanning wirings and the signal wirings, and a matrix connected to output terminals of the switching elements. In an active matrix type liquid crystal display device having a pixel electrode disposed, the signal wiring is bent near first and second pixel electrodes adjacent to each other, and one of the signal wirings is bounded by the bent portion as the first line.
The other is covered in the width direction by the pixel electrode, and the other is covered in the width direction by the second pixel electrode with the above-mentioned bend as a boundary, and the auxiliary capacitance wiring extends to a position overlapping with the bent part of the above-mentioned signal wiring. An active matrix liquid crystal display device having an electrode portion. 5. The active matrix type liquid crystal display device according to claim 1, further comprising: a light-shielding film disposed at a position between adjacent pixel electrodes on the insulating substrate. An active matrix type liquid crystal display device characterized by the above-mentioned. 6. The active matrix liquid crystal display device according to claim 5, wherein said light-shielding film is electrically connected to said auxiliary capacitance wiring or scanning wiring. .