JP5213596B2 - Liquid crystal display - Google Patents

Description

The present invention relates to a liquid crystal display device. In particular, the auxiliary capacitance can be increased as compared with the conventional liquid crystal display device while maintaining the aperture ratio without increasing the formation area of the auxiliary capacitance lower electrode. The present invention relates to a liquid crystal display device in which talk or the like hardly occurs.

A liquid crystal display device has characteristics of light weight, thinness, and low power consumption as compared with a CRT (cathode ray tube), and thus is used in many electronic devices for display. The liquid crystal display device changes the direction of liquid crystal molecules aligned in a predetermined direction by rubbing the alignment film by an electric field,
An image is displayed by changing the amount of light transmitted or reflected.

Liquid crystal display devices include TN (Twisted Nematic) mode and VA (Vertical Alignment).
) Mode, MVA (Multi-domain Vertical Alignment) mode, etc., are often used, and in particular, in recent years, they have a wide viewing angle characteristic and a high aperture ratio. Many mode liquid crystal display devices have been adopted.
Among these, a general configuration of a conventional TN mode liquid crystal display device will be described with reference to FIGS.

FIG. 9 is a plan view of one sub-pixel of a conventional TN mode liquid crystal display device. FIG. 10 shows FIG.
It is sectional drawing of XX. 11 is a cross-sectional view taken along line XI-XI in FIG. 12 is a schematic equivalent circuit diagram of one sub-pixel portion of the liquid crystal display device shown in FIG. FIG. 13 is a diagram showing voltage waveforms of respective portions of one subpixel of the liquid crystal display device shown in FIG.

The conventional liquid crystal display device 50 has a configuration in which a liquid crystal LC is sealed between an array substrate AR and a color filter substrate CF that are arranged to face each other. The array substrate AR is the first transparent substrate 1
A plurality of scanning lines 12 and signal lines 13 are formed in a matrix on the first transparent substrate 11 with a gate insulating film 14 interposed therebetween. Further, an auxiliary capacitance lower electrode 15 and a pixel electrode 16 are provided for each region surrounded by the scanning line 12 and the signal line 13, and the pixel electrode 1
6 is equivalently represented by a liquid crystal capacitance CLC in FIG. Usually, liquid crystal capacitance CLC
The auxiliary capacitor Cs formed by the auxiliary capacitor lower electrode 15 and the drain electrode D serving as the auxiliary capacitor upper electrode is connected in parallel. One end of the liquid crystal capacitor CLC is connected to a thin film transistor TFT (Thin Film Transistor) as a driving switching element, and the other end is connected to the surface of the second transparent substrate 22 via a color filter layer 23 and a top coat layer 24. A predetermined common potential Vc is applied to the common electrode 25 provided.

The source electrode S of the TFT is connected to the signal line 13 and supplied with the image signal Vs.
The drain electrode D of the FT is connected to one end of the liquid crystal capacitor CLC, that is, the pixel electrode 16 through the contact hole 17. Further, the gate electrode G of the TFT is connected to the scanning line 12 so that a gate pulse Vg having a predetermined voltage is applied. In the liquid crystal display device 50 shown here, the TFTs, the scanning lines 12 and the signal lines 13 are covered so as to cover them.
An interlayer film 19 is provided flat on the entire surface of the first transparent substrate 11 with a passivation film 18 so as to have a predetermined height. The pixel electrode 16 is provided on the surface of the interlayer film 19 having a predetermined height, and the cell gap is kept constant.
It is connected to the drain electrode D of FT. A liquid crystal LC is sealed between the pixel electrode 16 and the common electrode 25.

In the liquid crystal display device 50, a coupling capacitor is formed between the liquid crystal capacitor CLC and the gate electrode G. This coupling capacitance is a combination of the stray capacitance component CSD between the pixel electrode 16 and the scanning line 12 and the parasitic capacitance component CGD between the gate region and the drain region inside the TFT, and the latter parasitic capacitance component CGD is combined. It is dominant and its value varies considerably from one TFT to another.

The voltage waveform of each part of this one pixel will be described with reference to FIG. In the liquid crystal display device 50, the common potential Vc applied to the common electrode 25 is periodically inverted, and accordingly, a bias voltage that periodically inverts the image signal Vs applied to the signal line 13 is superimposed. Has been. First, when the gate pulse Vg is applied to the gate electrode G during the selection period of a predetermined subpixel, the TFT of this subpixel is turned on. At this time, the image signal Vs supplied from the signal line 13 is written to the pixel electrode 16 via the TFT, and so-called sampling is performed. Next, when this sub-pixel enters a non-selection period, the application of the gate pulse Vg is stopped and a low level gate voltage is applied, and the TFT is turned off, but the written image signal is held in the liquid crystal capacitor CLC. Yes.

When the transition from the selection period to the non-selection period occurs, the rectangular wave gate pulse Vg suddenly falls from the high level to the low level. At this time, the charge accumulated in the liquid crystal capacitance CLC by the coupling via the coupling capacitance described above is obtained. Discharge instantaneously. This causes a voltage shift ΔV (not shown) in the image signal Vs written to the pixel electrode 16. Accordingly, since the coupling capacitance value varies for each sub-pixel of the liquid crystal display device 50, the voltage shift ΔV also varies. As a result, the display screen of the liquid crystal display device 50 is periodically changed, So-called flickers and afterimages are produced and display quality is significantly deteriorated.

Conventionally, in order to suppress the absolute amount and variation of the voltage shift ΔV, a countermeasure has been taken in which the auxiliary capacitor Cs connected in parallel to the liquid crystal capacitor CLC is formed larger. That is, a charge sufficient to supplement the amount of charge discharged through the coupling capacitor is stored in advance in the auxiliary capacitor Cs. The auxiliary capacitor Cs is arranged by superposing the auxiliary capacitor lower electrode 15 independent of the other electrodes on the drain electrode D of the TFT electrically connected to the pixel electrode 16 serving as the auxiliary capacitor upper electrode in plan view. , A so-called Cs o for applying a voltage common to the common electrode 25 to the auxiliary capacitor lower electrode 15
n Common type storage capacity type is often used.

In recent years, miniaturized liquid crystal display devices for portable devices have been improved in definition, and accordingly, crosstalk due to parasitic capacitance between electrodes / wiring is likely to occur, so that a large auxiliary capacitance Cs is required. ing. In order to ensure such a large auxiliary capacity, the following Patent Document 1
In JP-A-5-265035, a liquid crystal display in which a first auxiliary capacitance electrode and a pixel electrode are overlapped, and a second auxiliary capacitance electrode connected to the auxiliary capacitance line is overlapped with the first auxiliary capacitance electrode. An apparatus invention is disclosed. Further, in the following Patent Document 2 (Japanese Patent Laid-Open No. 5-265036), the auxiliary capacitance electrode and the auxiliary capacitance line are formed separately and superimposed on different layers, and the first auxiliary capacitance is formed between the pixel electrode and the auxiliary capacitance line. And a liquid crystal display device in which a second auxiliary capacitance is formed between the auxiliary capacitance electrode and the auxiliary capacitance line. Patent Document 3 listed below discloses an invention of a liquid crystal display device in which an auxiliary capacitance wiring is formed from a transparent conductive layer and a metal layer having a narrow width formed on the surface thereof to increase the aperture ratio. ing
JP-A-5-265035 Japanese Patent Laid-Open No. 5-265036 JP-A-5-323378

However, in the liquid crystal display devices disclosed in Patent Documents 1 and 2, the auxiliary capacitor Cs is formed in the pixel electrode region, and if this dimension is set large, the aperture ratio of the pixel is sacrificed. It becomes impossible to obtain a good display contrast and to secure the transmittance (brightness). Further, in the liquid crystal display device disclosed in Patent Document 3, since the opaque auxiliary capacitance wiring portion can be narrowed, even if the aperture ratio can be improved,
Since the auxiliary capacitance is formed by the pair of auxiliary capacitance electrodes, there is a limit to increase of the storage capacitance. In particular, with the increase in definition of small liquid crystal display devices for portable devices, the ratio of signal lines or scanning lines other than the pixel electrodes also increases, so that the aperture ratio of the pixel decreases as the auxiliary capacitance Cs increases. The problem of this appears remarkably.

The present invention has been made to solve the above-mentioned problems of the prior art, and the auxiliary capacitance is maintained in the liquid crystal display of the conventional example while maintaining the aperture ratio without increasing the formation area of the auxiliary capacitance lower electrode. An object of the present invention is to provide a liquid crystal display device which can be increased more than the device, has a large aperture ratio, and is less likely to cause flicker, crosstalk, and the like.

In order to achieve the above object, the liquid crystal display device of the present invention comprises:
A first substrate and a second substrate disposed opposite to each other with a liquid crystal layer interposed therebetween;
On the liquid crystal layer side of the first substrate, a plurality of scanning lines and signal lines formed in a matrix with a first insulating film interposed therebetween are provided in the vicinity of intersections of the plurality of scanning lines and signal lines. A switching element, a storage capacitor line formed in parallel with the scanning line between the first insulating film and the first substrate, a storage capacitor lower electrode electrically connected to the storage capacitor line, and a plan view in the said first on an auxiliary capacitor is formed on the surface of the insulating film electrode position overlapping the auxiliary capacitor lower electrode, before Symbol switching element, the signal line, the storage capacitor upper electrode and an exposed portion of the first A second insulating film that covers a surface of the insulating film; a pixel electrode that is formed for each region partitioned by the scanning line and the signal line; and that is electrically connected to the switching element and the auxiliary capacitor upper electrode; First alignment film covering the surface of the pixel electrode Equipped with a,
A common electrode formed on the liquid crystal layer side of the second substrate; a second alignment film covering a surface of the common electrode;
A liquid crystal display device comprising:
At least one of the first substrate and the second substrate includes a columnar spacer whose top is in contact with the other of the first substrate and the second substrate,
A first auxiliary capacitor having the first insulating film as a dielectric is formed between the auxiliary capacitor upper electrode and the auxiliary capacitor lower electrode, and the surface of the columnar spacer is formed by the pixel electrode and the first alignment film . by coating, between the pixel electrode of the common electrode and the top surface of the columnar spacers, or by coating the surface of the columnar spacers in the second alignment film and the common electrode, the pixel electrode A second auxiliary capacitor is formed between the columnar spacer and the common electrode on the top surface;
An area of the top surface of the columnar spacer is formed to be equal to or smaller than an area of the auxiliary capacitor upper electrode, and the first alignment film or the second alignment film covering the top surface of the columnar spacer is Capacitance formation of the second auxiliary capacitor is performed by forming a dielectric of the second auxiliary capacitor with the first alignment film and the second alignment film in contact with the second alignment film or the first alignment film. area of the region is, that have the same or is it smaller than forming the area of the capacitance forming region of the first auxiliary capacitor.

In the liquid crystal display device of the present invention, as in the case of the liquid crystal display device of the conventional example, the first auxiliary capacitor using the first insulating film between the auxiliary capacitor upper electrode and the auxiliary capacitor lower electrode as a dielectric is formed. Yes. In addition, in the liquid crystal display device of the present invention, at least one of the first substrate and the second substrate is provided with a column spacer whose top is in contact with the other of the first substrate and the second substrate. The surface is covered with the pixel electrode and the first alignment film or the common electrode and the second alignment film. Therefore, in the liquid crystal display device of the present invention, the second auxiliary capacitance is formed between the common electrode and the pixel electrode on the top surface of the columnar spacer or between the pixel electrode and the common electrode on the top surface of the columnar spacer.

Therefore, according to the liquid crystal display device of the present invention, the first same as the case of the liquid crystal display device of the conventional example.
Since the second auxiliary capacitance is provided in addition to the auxiliary capacitance, the total auxiliary capacitance can be increased as compared with the conventional liquid crystal display device, and the liquid crystal display device is less likely to cause flicker and crosstalk. It becomes. On the contrary, according to the liquid crystal display device of the present invention, if the size of the total auxiliary capacitance is made the same as the auxiliary capacitance of the liquid crystal display device of the conventional example, the area of the auxiliary capacitance forming region is reduced. Since it can be made smaller than in the case of a liquid crystal display device, a liquid crystal display device having a large aperture ratio and capable of bright display. In the liquid crystal display device of the present invention, the same effect can be obtained regardless of whether the columnar spacer is formed on the first substrate or the second substrate.

In the liquid crystal display device of the present invention, the first alignment film and the second alignment layer on the top surface of the columnar spacers, that are in contact with each other and the second alignment layer or the first alignment layer.

When the first alignment film or the second alignment film on the top surface of the columnar spacer is in contact with the second alignment film or the first alignment film, the common electrode and the pixel electrode on the top surface of the columnar spacer or the pixel electrode and the columnar spacer A second auxiliary capacitor using the first alignment film and the second alignment film as a dielectric is formed between the top electrode and the common electrode. As a result, since both the first alignment film and the second alignment film are thin, the size of the second auxiliary capacitance is larger than when the first alignment film and the second alignment film are not in contact with each other. The effects of the present invention are more prominent.

In the liquid crystal display device of the present invention, the area of the top surface of the columnar spacer is not smaller or equal than the area of the storage capacitor upper electrode.

In the liquid crystal display device of the present invention, when the area of the top surface of the columnar spacer is increased, the size of the second auxiliary capacitor can be increased in proportion thereto. However, if the area of the top surface of the columnar spacer increases, the alignment disorder of the liquid crystal due to the presence of the alignment film on the side surface of the columnar spacer increases. It was decided to make it smaller.

In the liquid crystal display device of the present invention, it is preferable that the top portion of the columnar spacer is formed at a position overlapping the auxiliary capacitor upper electrode in plan view.

The auxiliary capacitor upper electrode is usually made of a metal material such as aluminum or an aluminum alloy, and is therefore light-shielding. Therefore, if the columnar spacer for forming the second auxiliary capacitance is formed at a position overlapping the auxiliary capacitance upper electrode in plan view, the opening degree is not reduced particularly by providing the columnar spacer. Therefore, according to the liquid crystal display device of the present invention, the aperture is not reduced while increasing the total auxiliary capacity. Therefore, even with the same aperture as the liquid crystal display device of the conventional example, more flicker and crosstalk are possible. Thus, the liquid crystal display device is less likely to occur.

In the liquid crystal display device of the present invention, it is preferable that the top of the columnar spacer is formed so as not to protrude from the auxiliary capacitor upper electrode in plan view.

If the top of the columnar spacer protrudes from the storage capacitor upper electrode in plan view, the disorder of liquid crystal alignment due to the alignment film formed on the side surface of the columnar spacer becomes visible, and part of the columnar spacer is This is not preferable because the transmitted light is shielded, leading to a decrease in the aperture.

In the liquid crystal display device of the present invention, it is preferable that a planarizing film made of a transparent resin layer is formed between the pixel electrode and the second insulating film.

If a planarizing film made of a transparent resin layer is formed between the pixel electrode and the second insulating film, the thickness (cell gap) of the liquid crystal layer is made uniform, so that the display image quality is improved, Since the formation region of the pixel electrode can be widened, the opening degree is improved.

The best mode for carrying out the present invention will be described below with reference to the embodiments and drawings. However, the embodiments shown below are not intended to limit the present invention to those described herein. The present invention can be equally applied to various modifications without departing from the technical idea shown in the claims. In each drawing used for the description in this specification, each layer and each member are displayed in different scales so that each layer and each member can be recognized on the drawing. However, it is not necessarily displayed in proportion to the actual dimensions.

FIG. 1 is a plan view of one sub-pixel that is seen through the color filter substrate of the liquid crystal display device of the first embodiment. 2 is a cross-sectional view taken along line II-II in FIG. 3 is a cross-sectional view taken along line III-III in FIG. FIG. 4 is a cross-sectional view corresponding to FIG. 2 in the liquid crystal display device of the second embodiment.
FIG. 5 is a cross-sectional view corresponding to FIG. 3 in the liquid crystal display device of the second embodiment. FIG. 6 is a plan view of one sub-pixel represented by seeing through the color filter substrate of the liquid crystal display device of the third embodiment. 7 is a cross-sectional view taken along line VII-VII in FIG. 8 is a cross-sectional view taken along line VIII-VIII in FIG.

[First Embodiment]
A liquid crystal display device 10A according to the first embodiment will be described with reference to FIGS. 1 to 3
The same reference numerals are given to the same components as those of the conventional liquid crystal display device 50 shown in FIGS. The array substrate AR of the liquid crystal display device 10A has a plurality of scans made of a metal such as aluminum or molybdenum on the first transparent substrate 11 made of transparent insulating glass or the like on the side facing the liquid crystal LC. The lines 12 are formed in parallel at equal intervals,
Further, the auxiliary capacitance line 15a is formed in parallel between the adjacent scanning lines 12 on the scanning line 12 side, and the auxiliary capacitance line 15a at the position where each pixel is to be formed is formed wide so that the auxiliary capacitance lower electrode 15 is formed.
It has become. Note that the scanning line 12 is formed so that the formation position of the gate electrode G of the TFT is partially wide.

A gate insulating film 14 made of silicon nitride, silicon oxide, or the like is laminated so as to cover the scanning line 12, the auxiliary capacitance line 15a, and the exposed portion of the glass substrate 11. This gate insulating film 14 corresponds to the first insulating film of the present invention. A semiconductor layer 20 made of amorphous silicon, polycrystalline silicon, or the like is formed on the gate insulating film 14 where the gate electrode G is to be formed. A plurality of signal lines 13 made of a metal such as aluminum or molybdenum are formed on the gate insulating film 14 so as to intersect the scanning lines 12, and the source electrode S of the TFT extends from the signal line 13. The source electrode S is in partial contact with the surface of the semiconductor layer 20.

Further, a drain electrode D formed simultaneously with the same material as the signal line 13 and the source electrode S is provided on the gate insulating film 14, and the drain electrode D is disposed in proximity to the source electrode S so as to form the semiconductor layer 20. Partially touching. The drain electrode D is a gate insulating film 14.
In FIG. 1 and FIG. 2, the both ends on the signal line 13 side of the auxiliary capacitance lower electrode 15 are extended so as to partially cover the surface of the auxiliary capacitance and the auxiliary capacitance lower electrode 15. in this case,
The drain electrode D becomes the auxiliary capacitance upper electrode, and the first auxiliary capacitance of each sub-pixel is formed by the overlapping portion of the drain electrode D and the auxiliary capacitance lower electrode 15 in plan view. The portion of the drain electrode D that partially covers the auxiliary capacitance lower electrode 15 corresponds to the auxiliary capacitance upper electrode of the present invention. Further, a region surrounded by the scanning lines 12 and the signal lines 13 corresponds to one sub-pixel region. The gate electrode G, the gate insulating film 14, the semiconductor layer 20, the source electrode S, and the drain electrode D constitute a TFT serving as a switching element.
Is formed.

Further, a passivation film 18 made of, for example, silicon nitride or silicon oxide is laminated so as to cover the exposed portions of the signal line 13, the TFT, and the gate insulating film 14, and the surface of the passivation film 18 is made of a transparent resin material such as a photoresist. Interlayer film 1 having a flat surface
9 are stacked. This passivation film 18 corresponds to the second insulating film of the present invention. A contact hole 17 is formed in the passivation film 18 and the interlayer film 19 at a position corresponding to the drain electrode D of the TFT.

In each subpixel, a transparent conductive material such as ITO (Indium Thin Oxide) or IZO (Indium Zinc Oxide) is provided so as to cover the inner surface of the contact hole 17, the surface of the interlayer film 19, and the inner surface of the opening 19a of the interlayer film 19. A pixel electrode 16 made of a conductive material is formed. Further, a first alignment film 21 made of polyimide, for example, is laminated on the surface of the pixel electrode 16 so as to cover all the pixels.

The color filter substrate CF is formed on the display area of the second transparent substrate 22 made of transparent insulating glass or the like on the side facing the liquid crystal LC, for example, corresponding to each pixel. A striped color filter layer 23 composed of any one of red (R), green (G), and blue (B) is provided. Further, a top coat layer 24 made of a transparent resin layer is formed on the surface of the color filter layer 23, and a common electrode 25 is laminated on the surface of the top coat layer 24 over the entire surface of the color filter substrate CF. A second alignment film 26 made of, for example, polyimide is laminated on the surface of the common electrode 25.

In the liquid crystal display device 10A of the first embodiment, for each pixel, the surface of the top coat layer 24 of the color filter substrate CF is superimposed on the drain electrode D serving as the storage capacitor upper electrode in plan view. A columnar spacer 30A is formed at a position to be used. The top surface of this columnar spacer 30 is formed in an area slightly narrower than the drain electrode D,
Further, in order to prevent the aperture ratio from being lowered, it is arranged so as not to protrude beyond the drain electrode D in plan view. The side surfaces and the top surface of the columnar spacer 30A are covered with the common electrode 25 and the second alignment film 26 from the color filter substrate CF. On the surface of the color filter substrate AR facing the liquid crystal LC, a light shielding member 31 is provided at a position corresponding to the base of the columnar spacer 30A, and at a position corresponding to the scanning line 12, the signal line 13 and the TFT of the array substrate AR. Is formed.

The array substrate AR and the color filter substrate CF thus formed are opposed to each other, and a sealing material is provided around both substrates to bond both substrates together.
TN liquid crystal display device 10A according to the first embodiment is obtained. Note that a backlight device having a well-known light source, a light guide plate, a diffusion sheet, and the like (not shown) is arranged below the array substrate AR, as in the case of the conventional liquid crystal display device.

In the liquid crystal display device 10 according to the first embodiment, the common electrode 25 formed on the top surface of the columnar spacer 30A is disposed so as to face the pixel electrode 16, the first alignment film 21, and the second alignment film 26. Will be. As a result, the thickness of the first alignment film 21 and the second alignment film 26 is significantly smaller than the thickness of the liquid crystal layer LC, so that the columnar spacer 30A is interposed between the pixel electrode 16 and the common electrode 25. On the top surface, a capacitor having the first alignment film 21 and the second alignment film 26 as dielectrics is formed. This capacitor corresponds to the second auxiliary capacitance of the present invention.

Therefore, in the liquid crystal display device 10A of the first embodiment, the first auxiliary capacitance is formed between the auxiliary capacitance lower electrode 15 and the drain electrode D corresponding to the auxiliary capacitance upper electrode, and the pixel electrode 16 and the common electrode 25 In the meantime, the second auxiliary capacitance is formed on the top surface of the columnar spacer 30A. Therefore, according to the liquid crystal display device 10A of the first embodiment, since the second auxiliary capacitor is provided in addition to the first auxiliary capacitor similar to the case of the liquid crystal display device of the conventional example, the liquid crystal display device of the conventional example is provided. Compared to the case, the total auxiliary capacity can be increased, and flicker and crosstalk are less likely to occur. Conversely, if the size of the total storage capacitor is made the same as the storage capacitor of the conventional liquid crystal display device, the area of the storage capacitor forming region can be made smaller than that of the conventional liquid crystal display device. Liquid crystal display device 10 having a large aperture ratio and capable of bright display
A is obtained.

In the liquid crystal display device 10A of the first embodiment, when the area of the top surface of the columnar spacer 30A is increased, the size of the second auxiliary capacitor can be increased in proportion thereto. However, when the area of the top surface of the columnar spacer 30A increases, the columnar spacer 30
Since the disorder of the alignment of the liquid crystal molecules due to the presence of the second alignment film 26 on the side surface of A becomes larger, the area of the top surface of the columnar spacer 30 is equal to or larger than the area of the drain electrode D that is the storage capacitor upper electrode. It is preferable to make it small.

[Second Embodiment]
In the liquid crystal display device 10A of the first embodiment, the columnar spacer 30A is replaced with the color filter substrate CF.
An example provided on the side is shown. However, the columnar spacer can also be provided on the array substrate AR side. A liquid crystal display device according to the second embodiment in which such columnar spacers are provided on the array substrate AR side will be described with reference to FIGS. 4 is a cross-sectional view corresponding to FIG. 2 of the liquid crystal display device 10A of the first embodiment, and FIG. 5 is a cross-sectional view corresponding to FIG. 3 similarly, and the color of the liquid crystal display device 10B of the second embodiment. A plan view of one subpixel shown through the filter substrate is as follows:
Since it is the same as the liquid crystal display device 10A of the first embodiment, the same reference numerals are given to portions having the same configuration as the liquid crystal display device 10A of the first embodiment, with reference to FIG. Is omitted.

In the liquid crystal display device 10B according to the second embodiment, the columnar spacer 30B is formed on the surface of the interlayer film 19 of the array substrate AR, and the side surface and the top surface of the columnar spacer 30B are sequentially formed on the pixel electrode 16 and the first alignment film 21. It is coated with. And color filter substrate C
On the F side, as in the case of the conventional example, the top coat layer 24 is successively formed on the surface of the color filter layer 23.
The common electrode 25 and the second alignment film 26 are covered, and the surface of the second alignment film 26 is substantially flat. The first alignment film 21 on the top surface of the columnar spacer 30B is in direct contact with the second alignment film 26 of the color filter substrate CF. Therefore, in the liquid crystal display device 10B of the second embodiment, as in the case of the liquid crystal display device 10A of the first embodiment, the top surface of the columnar spacer 30B is between the pixel electrode 16 and the common electrode 25. A capacitor having the first alignment film 21 and the second alignment film 26 as dielectrics, that is, a second auxiliary capacitor is formed. Therefore, the liquid crystal display device 10B of the second embodiment has substantially the same effect as the liquid crystal display device 10A of the first embodiment.

[Third Embodiment]
A liquid crystal display device 10C according to the second embodiment will be described with reference to FIGS. 6-8.
The same reference numerals are assigned to the same components as those of the liquid crystal display device 10A of the first embodiment, and the detailed description thereof is omitted. The configuration of the liquid crystal display device 10C of the third embodiment is different from that of the liquid crystal display device 10A of the first embodiment in that the columnar spacers 30C formed on the color filter substrate CF are in the shape of elongated ribs. is there. When the columnar spacer 30C has such a long and narrow rib shape, the liquid crystal display devices 10A and 10B of the first and second embodiments are used.
However, since the columnar spacer 30C can be arranged at a position away from the display area of one subpixel, the alignment of liquid crystal molecules in the display area is disturbed due to the presence of the columnar spacer 30C. Therefore, a liquid crystal display device with good display image quality is obtained. 6 shows an example in which the columnar spacer 30C has a substantially trapezoidal shape in which the scanning line 12 side has a long side portion and the opposite side to the scanning line 12 has a short side portion in a plan view. With such a shape, even when the color filter substrate CF is pressed from the outside, the cross-sectional area necessary for maintaining the cell gap is secured, and the disorder of the alignment of the liquid crystal molecules on the short side can be reduced. As a result, a good display image quality can be obtained.

In each of the first to third embodiments, the case of the TN mode liquid crystal display device has been described. However, the present invention is not limited to the VA mode, the MVA mode, and the OCB (Op) excellent in high-speed response.
The present invention is equally applicable to a vertical electric field type liquid crystal display device such as a tically compensated bend mode. In the first to third embodiments, the pixel electrode 16 is formed on the surface of the interlayer film 19. However, the interlayer film 19 is not necessarily required. The present invention is also applicable to a liquid crystal display device formed on the surface of the two insulating film 18.

FIG. 3 is a plan view of one sub pixel that is seen through a color filter substrate of the liquid crystal display device of the first embodiment. It is sectional drawing of the II-II line of FIG. It is sectional drawing of the III-III line | wire of FIG. It is sectional drawing corresponding to FIG. 2 in the liquid crystal display device of 2nd Embodiment. It is sectional drawing corresponding to FIG. 3 in the liquid crystal display device of 2nd Embodiment. It is a top view for 1 sub-pixel represented by seeing through the color filter substrate of the liquid crystal display device of a 3rd embodiment. It is sectional drawing of the VII-VII line of FIG. It is sectional drawing of the VIII-VIII line of FIG. It is a top view for 1 sub pixel of the liquid crystal display device of the conventional TN mode. It is sectional drawing of the XX line of FIG. It is sectional drawing of the XI-XI line of FIG. FIG. 10 is a schematic equivalent circuit diagram of one sub-pixel portion of the liquid crystal display device shown in FIG. 9. It is a figure which shows the voltage waveform of each part of 1 sub pixel of the liquid crystal display device shown in FIG.

Explanation of symbols

10A to 10C: liquid crystal display device 11: first transparent substrate 12: scanning line 13: signal line
14: Gate insulating film 15: Lower capacitance lower electrode 15a: Auxiliary capacitance line 16: Pixel electrode 1
7: Contact hole 18: Passivation film 19: Interlayer film 20: Semiconductor layer 2
1: first alignment film 22: second transparent substrate 23: color filter layer 24: topcoat layer 25: common electrode 26: second alignment film 30A to 30C: columnar spacer 31: light shielding layer AR: array substrate CF: color Filter substrate LC: Liquid crystal

Claims (4)

A first substrate and a second substrate disposed opposite to each other with a liquid crystal layer interposed therebetween;
On the liquid crystal layer side of the first substrate, a plurality of scanning lines and signal lines formed in a matrix with a first insulating film interposed therebetween are provided in the vicinity of intersections of the plurality of scanning lines and signal lines. A switching element, a storage capacitor line formed in parallel with the scanning line between the first insulating film and the first substrate, a storage capacitor lower electrode electrically connected to the storage capacitor line, and a plan view in the said first on an auxiliary capacitor is formed on the surface of the insulating film electrode position overlapping the auxiliary capacitor lower electrode, before Symbol switching element, the signal line, the storage capacitor upper electrode and an exposed portion of the first A second insulating film that covers a surface of the insulating film; a pixel electrode that is formed for each region partitioned by the scanning line and the signal line; and that is electrically connected to the switching element and the auxiliary capacitor upper electrode; First alignment film covering the surface of the pixel electrode Equipped with a,
A common electrode formed on the liquid crystal layer side of the second substrate; a second alignment film covering a surface of the common electrode;
A liquid crystal display device comprising:
At least one of the first substrate and the second substrate includes a columnar spacer whose top is in contact with the other of the first substrate and the second substrate,
A first auxiliary capacitor having the first insulating film as a dielectric is formed between the auxiliary capacitor upper electrode and the auxiliary capacitor lower electrode, and the surface of the columnar spacer is formed by the pixel electrode and the first alignment film . by coating, between the pixel electrode of the common electrode and the top surface of the columnar spacers, or by coating the surface of the columnar spacers in the second alignment film and the common electrode, the pixel electrode A second auxiliary capacitor is formed between the columnar spacer and the common electrode on the top surface;
An area of the top surface of the columnar spacer is formed to be equal to or smaller than an area of the auxiliary capacitor upper electrode, and the first alignment film or the second alignment film covering the top surface of the columnar spacer is Capacitance formation of the second auxiliary capacitor is performed by forming a dielectric of the second auxiliary capacitor with the first alignment film and the second alignment film in contact with the second alignment film or the first alignment film. area of the region is, the first auxiliary capacitor of the capacitor formation region liquid crystal display device area that is equal to or formed it smaller than the of.   The liquid crystal display device according to claim 1, wherein a top portion of the columnar spacer is formed at a position overlapping with the storage capacitor upper electrode in plan view.   The liquid crystal display device according to claim 1, wherein a top portion of the columnar spacer is formed so as not to protrude from the auxiliary capacitance upper electrode in a plan view.   The liquid crystal display device according to claim 1, wherein a planarizing film made of a transparent resin layer is formed between the pixel electrode and the second insulating film.

Images