JPH112841A - Liquid crystal display device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain the display device of high picture quality reduced in longitudinal smears by arranging a video signal wire and a color filter layer so that they overlap with each other when viewed perpendicularly to the planes of substrates. SOLUTION: On a 1st substrate (TFT substrate) SUB1 as an active matrix substrate, a counter electrode CT and a pixel electrode PX are arranged. On a 2nd substrate SUB2 as a color filter substrate, on the other hand, a black matraix BM and a color filter layer FIL are formed and on them, an overcoat film OC is formed. Then the video signal line DL and color filter layer-FIL overlap with each other when viewed from a direction perpendicular to the planes of the substrates SUB1 and SUB2. Here, the overlap quantity OLQ between the video signal line DL and color filter layer FIL is 2 μm. Thus, light leaking between the video signal line DL and counter electrode CT is reducible.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a liquid crystal display device, and more particularly to a horizontal electric field type liquid crystal display device capable of suppressing the occurrence of vertical smear and enabling high-quality image display.

[0002]

2. Description of the Related Art Active matrix type liquid crystal display devices are widely used as image display means for monitoring various information terminals and other devices.

When this type of liquid crystal display device is classified according to the driving mode of the liquid crystal, it is roughly classified into a "vertical electric field system" and a "lateral electric field system".

A vertical electric field type liquid crystal display device has a liquid crystal composition (hereinafter, simply referred to as a liquid crystal or a liquid crystal layer), each of which corresponds to a unit pixel on a liquid crystal layer side of a transparent substrate which is disposed to face each other. On the surface of the region, a pixel electrode made of a transparent electrode and a common electrode are provided so as to face each other, and light transmitted through the liquid crystal layer by an electric field generated perpendicularly to the transparent substrate between the pixel electrode and the common electrode. The modulation is performed.

On the other hand, a liquid crystal display device of the in-plane switching mode employs a transparent substrate disposed opposite to each other with a liquid crystal layer interposed therebetween.
A pixel electrode and a counter electrode are provided on a region surface corresponding to a unit pixel on one or both of the liquid crystal layers, and the liquid crystal is generated between the pixel electrode and the counter electrode by an electric field component generated substantially in parallel with the transparent substrate. The light transmitted through the layer is modulated.

The liquid crystal display device of the horizontal electric field type is different from the liquid crystal display device of the vertical electric field type in that a clear image can be recognized even when the display surface is observed from a large angle field of view. It has become known.

[0007] A liquid crystal display device having such a configuration is described in detail in, for example, Japanese Patent Application Laid-Open No. 6-160878.

The above-mentioned in-plane switching mode liquid crystal display device displays an image, for example, a first substrate forming an active matrix substrate and a second substrate forming a color filter substrate, which are opposing transparent substrates. A backlight unit serving as a light source is housed and integrated in a housing formed of an upper shield case and a lower case. A polarizing plate is attached to both sides of the first and second substrates so that only a certain amount of polarized light is transmitted.

Further, for example, on the color filter substrate, a black matrix is formed at least in a region corresponding to at least a region where a thin film transistor is formed on the active matrix substrate and a region where transmitted light cannot be controlled, such as around a wiring.

In the case of the horizontal electric field method, the liquid crystal is driven by an electric field generated between the pixel electrode and the counter electrode and substantially parallel to the plane of the substrate. In this case, if a low-resistance material is present on the color filter substrate, the lines of electric force generated from the pixel electrode or the counter electrode are terminated by the low-resistance material, the electric field intensity decreases, and the driving voltage increases.

Therefore, generally, a high-resistance resin composition is used as a black matrix forming material. In this case, the OD value (abbreviation of Optical Density) is not sufficiently large as compared with a black matrix using a metal material, so that the light shielding characteristics of the black matrix itself deteriorate.

In the prior art, no countermeasures against such a decrease in light-shielding characteristics are taken into account, and accordingly,
No problem has been raised with respect to blocking transmitted light in areas that do not work properly.

[0013]

In the above-mentioned prior art in-plane switching type liquid crystal display device, there is a region where the liquid crystal cannot operate normally because it cannot be controlled by a scanning signal or a video signal input from an external circuit. In particular, light is transmitted in this portion even though black is displayed due to different applied voltages between the video signal wiring and the pixel electrode or the counter electrode adjacent to the video signal wiring. Sometimes.

In order to shield this portion from light, a black matrix is formed on the color filter substrate to block the light. However, the OD value is so low that the light cannot be completely blocked in some cases.
This causes a problem that crosstalk occurs.

The above-mentioned crosstalk refers to, for example, a phenomenon in which, when a window screen is displayed at the center of the screen, the luminance of the background color changes in the vertical or horizontal direction at the same width as the window width.

Crosstalk generated in a vertical electric field type liquid crystal display device is caused by the influence of the potential of another pixel during the holding period due to capacitive coupling of a pixel electrode, a wiring electrode, a counter electrode and the like. In the design, the influence is reduced by optimizing the above capacity ratio. However, the crosstalk that is a problem to be solved by the present invention is not due to such capacitive coupling, and the luminance of the background color changes in the same width as the window width due to the effect of leaked light that cannot be completely blocked. It is caused by that.

Accordingly, an object of the present invention is to provide a liquid crystal display device in which crosstalk caused by the influence of the above-mentioned leaked light is prevented.

[0018]

In order to achieve the above object, a first means of the present invention is to form a plurality of scanning signal wirings and video signal wirings near an intersection of the scanning signal wirings and the video signal wirings. A switching element, a pixel electrode to which a driving voltage is applied via the switching element,
A first substrate constituting an active matrix substrate including a counter electrode arranged so as to apply an electric field substantially parallel to the plane of the substrate together with the pixel electrode, a black matrix formed of a resin composition, A liquid crystal composition is sandwiched between a second substrate constituting a color filter substrate on which a color filter layer arranged corresponding to a pixel is formed, and a plane of each substrate is interposed between the pixel electrode and a counter electrode. In a liquid crystal display device that performs image display by changing the light transmittance of the liquid crystal composition by an electric field component generated substantially in parallel, when viewed from a direction perpendicular to the plane of each substrate, the video signal wiring and It is characterized in that at least a part of the color filter layer is arranged so as to overlap.

The second means of the present invention comprises: a plurality of scanning signal wirings and video signal wirings; a switching element formed near an intersection of the scanning signal wiring and the video signal wiring; A first substrate forming an active matrix substrate including a pixel electrode to which a voltage is applied, and a counter electrode disposed so as to apply an electric field substantially parallel to the plane of the substrate together with the pixel electrode;
A liquid crystal composition is sandwiched between a black matrix formed of a resin composition and a second substrate forming a color filter substrate formed with a color filter layer disposed corresponding to each pixel, and is opposed to the pixel electrode. In a liquid crystal display device that performs image display by changing the light transmittance of the liquid crystal composition by an electric field component generated substantially in parallel with the plane of each substrate between electrodes and a direction perpendicular to the plane of each substrate. When viewed from above, an end of the color filter layer in a direction parallel to the video signal wiring is arranged inside the line width of the video signal wiring.

Further, a third means of the present invention comprises a plurality of scanning signal wirings and video signal wirings, a switching element formed near an intersection of the scanning signal wiring and the video signal wiring, and a driving device via the switching element. A first substrate constituting an active matrix substrate, comprising: a pixel electrode to which a voltage is applied; and a counter electrode disposed so as to apply an electric field substantially parallel to the plane of the substrate together with the pixel electrode. Black matrix composed of an object and a color filter layer arranged corresponding to each pixel.
The liquid crystal composition is sandwiched between the substrates, and the light transmittance of the liquid crystal composition is changed by an electric field component generated substantially in parallel with the plane of each substrate between the pixel electrode and the counter electrode. In a liquid crystal display device for displaying an image, the color filter layers adjacent in the direction parallel to the scanning signal lines are arranged so as to overlap each other on the black matrix.

Still further, according to a fourth aspect of the present invention, a plurality of scanning signal wirings and video signal wirings, a switching element formed near an intersection of the scanning signal wirings and the video signal wirings, A pixel electrode to which a drive voltage is applied, and a counter electrode disposed so as to apply an electric field substantially parallel to a plane of a substrate together with the pixel electrode, and one of the pixel electrode and the counter electrode is provided. A first substrate which is arranged in parallel with the video signal wiring to form an active matrix substrate, and a second substrate which is formed with a black matrix made of a resin composition and a color filter layer arranged corresponding to each pixel Between the pixel electrode and the counter electrode, and an electric field component generated substantially in parallel with the plane of each substrate between the pixel electrode and the counter electrode. In a liquid crystal display device that performs image display by changing the transmittance, when viewed from a direction perpendicular to the plane of each of the substrates, an end of the color filter layer in a direction parallel to the video signal wiring is formed in an adjacent pixel. It is characterized in that it is arranged inside the width of a pixel electrode or a counter electrode arranged in parallel adjacent to a video signal wiring.

The fifth means of the present invention comprises a plurality of scanning signal wirings and video signal wirings, a switching element formed near an intersection between the scanning signal wirings and the video signal wirings, and a driving device via the switching element. A pixel electrode to which a voltage is applied, and a counter electrode arranged to apply an electric field substantially parallel to the plane of the substrate together with the pixel electrode, and one of the pixel electrode and the counter electrode is Active
A liquid crystal composition is sandwiched between a first substrate constituting a matrix substrate and a second substrate having a black matrix composed of a resin composition and a color filter layer arranged corresponding to each pixel, In a liquid crystal display device which performs image display by changing the light transmittance of the liquid crystal composition by an electric field component generated substantially in parallel with the plane of each substrate between a pixel electrode and a counter electrode, an adjacent color filter layer A color filter material having a chromaticity different from that of the color filter material is formed on at least a part of a black matrix disposed to face the video signal wiring, and an end of the color filter material in a direction parallel to the video signal wiring. A portion is disposed inside the width of the pixel electrode or the counter electrode which is disposed adjacent to and parallel to the video signal wiring.

According to the above-mentioned means of the present invention, leakage light generated between the video signal wiring and the counter electrode is shielded, so-called vertical smear is reduced, and a high-quality display device is obtained.

Still other objects and features of the present invention will become apparent from the following description with reference to the drawings.

[0025]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of the present invention will be described in which the present invention is applied to an active matrix type color liquid crystal display device. In the drawings described below, components having the same function are denoted by the same reference numerals, and a repeated description thereof will be omitted.

<< Planar Configuration of Matrix Unit (Pixel Unit) >> FIG. 7 is a plan view showing one pixel of the active matrix type color liquid crystal display device of the present invention, a light-shielding region of the black matrix BM and its periphery.

As shown in FIG. 7, each pixel has a scanning signal line (gate signal line or horizontal signal line) GL, a counter voltage signal line (counter electrode line) CL, and two adjacent video signal lines (drain). The signal line or the vertical signal line) is arranged in an intersecting region with the DL (in a region surrounded by four signal lines).

Each pixel includes a thin film transistor TFT, a storage capacitor Cstg, a pixel electrode PX, and a counter electrode CT. The scanning signal lines GL and the counter voltage signal lines CL extend in the left-right direction in FIG. The video signal lines DL extend in the up-down direction, and a plurality of video signal lines DL are arranged in the left-right direction. The pixel electrode PX is connected to the thin film transistor TFT, and the counter electrode CT is integrated with the counter voltage signal line CL.

The pixel electrode PX and the counter electrode CT are opposed to each other, and the alignment state of the liquid crystal LC is controlled by an electric field between each pixel electrode PX and the counter electrode CT, and the transmitted light is modulated to control the display. The pixel electrode PX and the counter electrode CT are formed in a comb-like shape, and each is an electrode that is elongated in the vertical direction in FIG.

The number O (number of comb teeth) of the counter electrode CT in one pixel is equal to the number P (number of comb teeth) of the pixel electrode PX and O =
It is configured to always have the relationship of P + 1 (O = 2, P = 1 in this embodiment). This is because the counter electrode CT and the pixel electrode PX are alternately arranged, and the counter electrode CT is always adjacent to the video signal line DL.

Thus, the counter electrode CT and the pixel electrode PX are
The electric field lines from the video signal line DL can be shielded by the counter electrode CT so that the electric field between them is not affected by the electric field generated from the video signal line DL.

Since the potential of the counter electrode CT is always supplied from the outside by the counter voltage signal line CL, the potential is stable. Therefore, there is almost no change in potential even adjacent to the video signal line DL. In addition, since the geometric position of the pixel electrode PX from the video signal line DL becomes farther,
The parasitic capacitance between the pixel electrode PX and the video signal line DL is greatly reduced, and the fluctuation of the pixel electrode potential Vs due to the video signal voltage can be controlled.

As a result, crosstalk (defective image quality called vertical smear) occurring in the vertical direction can be suppressed.

The electrode width W between the pixel electrode PX and the counter electrode CT
Each of p and Wc is set to 6 μm, which is set sufficiently larger than 4.5 μm which exceeds the maximum set thickness of the liquid crystal layer described later.
It is preferable to have a margin of 20% or more in consideration of processing variations in manufacturing. Therefore, it is preferable that the margin be sufficiently larger than 5.4 μm.

Thus, the electric field component applied to the liquid crystal layer parallel to the substrate surface becomes larger than the electric field component in the direction perpendicular to the substrate surface, and it is possible to suppress an increase in the voltage for driving the liquid crystal. The maximum value of the electrode width Wp, Wc of each electrode is
It is preferable that the distance be smaller than the distance L between the pixel electrode PX and the counter electrode CT.

This is because, if the distance between the electrodes is too small, the curvature of the lines of electric force becomes severe, and the region where the electric field component perpendicular to the substrate surface is larger than the electric field component parallel to the substrate surface increases. This is because an electric field component parallel to the above cannot be efficiently applied to the liquid crystal layer. Therefore, the pixel electrode PX and the counter electrode C
The interval L between T needs to be larger than 7.2 μm if the margin is 20%. In this embodiment, the diagonal is about 1
Since the pixel pitch is about 60 μm because the resolution is 4.5 cm (5.7 inches) and the resolution is 640 × 480 dots, the distance L> 7.2 μm by dividing the pixel into two.
Was realized.

The electrode width of the video signal line DL is set to 8 μm, which is slightly wider than the pixel electrode PX and the counter electrode CT in order to prevent disconnection, and the interval between the video signal line DL and the counter electrode CT is short-circuited. In order to prevent this, an interval of about 1 μm is provided, a video signal line DL is formed on the upper side of the gate insulating film, and a counter electrode CT is formed on the lower side.

On the other hand, the electrode interval between the pixel electrode PX and the counter electrode CT changes depending on the liquid crystal material used. this is,
Since the electric field strength that achieves the maximum transmittance varies depending on the liquid crystal material, the electrode spacing is set according to the liquid crystal material, and within the range of the maximum amplitude of the signal voltage set by the withstand voltage of the video signal driving circuit (signal side driver) used. , So that the maximum transmittance can be obtained. When a liquid crystal material described later is used, the electrode interval is about 15 μm.

In this embodiment, a black matrix BM is formed on the gate line GL, the counter voltage signal line CL, the thin film transistor TFT, the drain line DL, and between the drain line DL and the counter electrode CT in plan view.

<< Cross-Sectional Structure of Matrix (Pixel) >> FIG. 8 shows a thin film transistor TF taken along the line 4-4 in FIG.
FIG. 9 is a cross-sectional view of the storage capacitor Cstg taken along the line 5-5 in FIG. 7, and FIG. 10 is a cross-sectional view of the vicinity of one pixel electrode in the image display area of the horizontal electric field type liquid crystal display substrate. It is sectional drawing of a part.

As shown in FIG. 10, a thin film transistor TFT, a storage capacitor Cstg (not shown), and an electrode group C are provided on the lower transparent glass substrate SUB1 side with respect to the liquid crystal layer LC.
T, PX are formed, and a color filter FIL and a black matrix B for shading are formed on the upper transparent glass substrate SUB2 side.
An M pattern is formed. Although not publicly known,
As proposed in Japanese Patent Application No. 7-198349 by the same applicant, it is also possible to form the pattern of the light-shielding black matrix BM on the lower transparent glass substrate SUB1 side.

On the inner surface (on the liquid crystal LC side) of each of the transparent glass substrates SUB1 and SUB2, alignment films ORI11 and ORI12 for controlling the initial alignment of the liquid crystal are provided. Polarizing plates POL1 and POL2 whose polarization axes are orthogonally arranged (crossed Nicol arrangement) are provided on the outer surfaces of each.

Next, the lower transparent glass substrate SUB1 side (T
The configuration of the FT substrate will be described in detail.

TFT Substrate << Thin Film Transistor >> The thin film transistor TFT operates so that the channel resistance between the source and the drain decreases when a positive bias is applied to the gate electrode GT, and the channel resistance increases when the bias is set to zero.

As shown in FIG. 8, the thin film transistor TFT has a gate electrode GT, a gate insulating film GI, and an i-type (intrinsic, not doped with a conductivity type determining impurity) amorphous silicon (Si) made of i. Type semiconductor layer AS, a pair of source electrode SD1, drain electrode SD
2

It should be understood that the source and the drain are originally determined by the bias polarity between them, and in the circuit of this liquid crystal display device, the polarity is inverted during the operation, so that it is understood that the source and the drain are switched during the operation. However, in the following description, one is fixed and the other is fixed as a drain for convenience.

<< Gate Electrode GT >> The gate electrode GT is formed continuously with the scanning signal line GL, and a part of the scanning signal line GL is configured as the gate electrode GT. The gate electrode GT is a portion exceeding the active region of the thin film transistor TFT, and is formed larger than that so as to completely cover the i-type semiconductor layer AS (as viewed from below).

Thus, in addition to the role of the gate electrode GT, the gate electrode GT is designed so that external light and backlight do not hit the i-type semiconductor layer AS. In this example, the gate electrode GT is formed of a single-layer conductive film g1. As the conductive film g1, for example, an aluminum (Al) film formed by sputtering is used, and an anodic oxide film AOF of Al is provided thereon.

<< Scanning Signal Line GL >> The scanning signal line GL is formed of the conductive film g1. The conductive film g1 of the scanning signal line GL is formed in the same manufacturing process as the conductive film g1 of the gate electrode GT, and is integrally formed. Through this scanning signal line GL, a gate voltage Vg is supplied from an external circuit to the gate electrode GT.

An anodic oxide film AOF of Al is also provided on the scanning signal line GL. The portion that intersects with the video signal line DL is made thin to reduce the probability of short-circuit with the video signal line DL, and is made bifurcated so that even if it is short-circuited, it can be separated by laser trimming.

<< Counter Electrode CT >> The counter electrode CT is formed of the same conductive film g1 as the gate electrode GT and the scanning signal line GL. Also, an anodic oxide film A of Al is formed on the counter electrode CT.
An OF is provided. The counter electrode CT has an anodic oxide film A
Since they are completely covered with the OF, even if they are brought as close as possible to the video signal lines, they will not be short-circuited.

Further, they may be configured to cross each other. The counter electrode CT is configured to apply a counter voltage Vcom. In this embodiment, the counter voltage Vc
om is a potential lower than an intermediate DC potential between the minimum level drive voltage Vdmin and the maximum level drive voltage Vdmax applied to the video signal line DL by a feedthrough voltage ΔVs generated when the thin film transistor element TFT is turned off. However, if you want to reduce the power supply voltage of the integrated circuit used in the video signal drive circuit to about half,
An AC voltage may be applied.

<< Counter Voltage Signal Line CL >> Counter Voltage Signal Line C
L is composed of the conductive film g1. The conductive film g1 of the counter voltage signal line CL is formed in the same manufacturing process as the conductive film g1 of the gate electrode GT, the scanning signal line GL, and the counter electrode CT, and is formed integrally with the counter electrode CT.

The counter voltage Vcom is supplied to the counter electrode CT from an external circuit through the counter voltage signal line CL. or,
An anodic oxide film AOF of Al is also provided on the counter voltage signal line CL. Note that the portion that intersects with the video signal line DL is
Like the scanning signal line GL, it may be made thinner to reduce the probability of short-circuiting with the video signal line DL, or it may be split into two parts so that even if it is short-circuited, it can be separated by laser trimming.

<< Insulating Film GI >> The insulating film GI is used as a gate insulating film for applying an electric field to the semiconductor layer AS together with the gate electrode GT in the thin film transistor TFT. The insulating film GI is formed above the gate electrode GT and the scanning signal line GL.

As the insulating film GI, for example, plasma CVD
The silicon nitride film formed by
It is formed to a thickness of nm (240 nm in this embodiment).

The gate insulating film GI is formed in the matrix portion A
R is formed so as to surround the entirety of R, and the peripheral portion is removed so as to expose the external connection terminals DTM and GTM. Also,
The insulating film GI also contributes to electrical insulation between the scanning signal lines GL and the counter voltage signal lines CL and the video signal lines DL.

<< i-type semiconductor layer AS >> i-type semiconductor layer AS
Is amorphous silicon and is formed with a thickness of 20 to 220 nm (about 200 nm in this embodiment). Layer d
Numeral 0 denotes an N (+)-type amorphous silicon semiconductor layer doped with phosphorus (P) for ohmic contact. An i-type semiconductor layer AS is present on the lower side, and a conductive film d1 (d2) is present on the upper side. It is left only in places.

The i-type semiconductor layer AS is also provided between the scanning signal line GL and the intersection of the counter signal line CL and the video signal line DL. The i-type semiconductor layer AS at the intersection reduces a short circuit between the scanning signal line GL and the opposing signal line CL and the video signal line DL at the intersection.

<< Source electrode SDI, drain electrode SD
2 >> Each of the source electrode SDI and the drain electrode SD2 is composed of a conductive film d1 in contact with the N (+) type semiconductor layer d0 and a conductive film d2 formed thereon.

The conductive film d1 is formed of a chromium (Cr) film formed by sputtering to a thickness of 50 to 100 nm (about 60 nm in this embodiment). Since the stress increases when the Cr film is formed to have a large thickness, the Cr film has a thickness of 200 nm.
It is formed in a range that does not exceed a certain thickness. Cr film is N
To improve the adhesion to the (+) type semiconductor layer d0,
2 is used for the purpose of a so-called barrier layer that prevents Al from diffusing into the N (+) type semiconductor layer d0.

As the conductive film d1, a refractory metal (Mo, Ti, Ta, W) film or a refractory metal silicide (MoSi ₂ , TiSi ₂ , TaSi ₂ , WSi ₂ ) film may be used in addition to the Cr film. .

The conductive film d2 is formed by sputtering Al
It is formed to a thickness of 0 to 500 nm (about 400 nm in this embodiment). The Al film has a smaller stress than the Cr film and can be formed to have a large thickness.
It has functions of reducing the resistance values of D1, the drain electrode SD2, and the video signal line DL, and ensuring the step over caused by the gate electrode GT and the i-type semiconductor layer AS (to improve the step coverage).

After patterning the conductive films d1 and d2 with the same mask pattern, the N (+) type semiconductor layer d0 is removed using the same mask or using the conductive films d1 and d2 as a mask. That is, the i-type semiconductor layer AS
The remaining N (+) type semiconductor layer d0 is a conductive film d1,
Portions other than the conductive film d2 are removed by self-alignment.
At this time, since the N (+)-type semiconductor layer d0 is etched so as to completely remove its thickness, the i-type semiconductor layer A is removed.
Although the surface portion of S is also slightly etched, its degree may be controlled by the etching time.

<< Video Signal Line DL >> The video signal line DL is composed of the second conductive film d2 and the third conductive film d3 in the same layer as the source electrode SD1 and the drain electrode SD2. The video signal line DL is formed integrally with the drain electrode SD2.

<< Pixel Electrode PX >> The pixel electrode PX is the second conductive film d of the same layer as the source electrode SD1 and the drain electrode SD2.
2, the third conductive film d3. Also, the pixel electrode P
X is formed integrally with the source electrode SD1.

<< Storage Capacitor Cstg >> The pixel electrode PX is formed so as to overlap the counter voltage signal line CL at the end opposite to the end connected to the thin film transistor TFT. This superposition is, as is clear from FIG.
A storage capacitor (capacitance element) Cstg is formed in which the pixel electrode PX is one electrode PL2 and the counter voltage signal line CL is the other electrode PL1. The dielectric film of the storage capacitor Cstg includes an insulating film GI used as a gate insulating film of the thin film transistor TFT and an anodic oxide film AOF.

As shown in FIG. 7, the storage capacitor Cstg is formed in the conductive film g1 of the counter voltage signal line CL in plan view.

In this case, the storage capacitor Cstg is made of aluminum because the material of the electrode positioned below the insulating film GI is formed of Al and the surface thereof is anodized. It is possible to obtain a storage capacitor which is less likely to cause adverse effects due to a point defect (short-circuit with an electrode positioned on the upper side) caused by a so-called hillock or the like.

<< Protective Film PSV1 >> Thin Film Transistor TF
On T, a protective film PSV1 is provided. Protective film PS
V1 is formed mainly to protect the thin film transistor TFT from moisture and the like, and uses a material having high transparency and good moisture resistance. The protective film PSV1 is formed of, for example, a silicon oxide film or a silicon nitride film formed by a plasma CVD apparatus, and has a thickness of about 500 nm.

The protective film PSV1 is formed so as to surround the entire matrix portion AR, and the peripheral portion has an external connection terminal DT.
M and GTM have been removed to expose. Regarding the thickness relationship between the protective film PSV1 and the gate insulating film GI, the former is made thicker in consideration of the protective effect, and the latter is made thinner in consideration of the transconductance gm of the transistor.

[0072] The color filter substrate Next, FIG. 7, back to FIG. 10, the upper transparent glass substrate SUB
The configuration of the two sides (color filter substrate) will be described in detail.

<< Light shielding film BM >> Upper transparent glass substrate SUB
On the second side, an unnecessary gap (pixel electrode PX and counter electrode CT)
Transmitted light from the gap other than the gap between
A light-shielding film BM (a so-called black matrix) is formed so as not to lower the contrast ratio and the like. Light shielding film BM
Also serves to prevent external light or backlight light from entering the i-type semiconductor layer AS. That is, the i-type semiconductor layer AS of the thin film transistor TFT is sandwiched between the upper and lower light-shielding films BM and the large gate electrode GT, so that external natural light or backlight does not shine.

The closed polygonal outline of the light-shielding film BM shown in FIG. 7 indicates an opening in which the light-shielding film BM is not formed. This contour pattern is an example.

In a horizontal electric field type liquid crystal display device, a black matrix having the highest possible resistance is suitable.
Generally, a resin composition is used. For this resistance standard,
Although it is not publicly known, Japanese Patent Application No. 7-1919 filed by the same applicant
No. 94. That is, if the specific resistance of the liquid crystal composition LC is described as 10 ^N as 10 ^N , then the specific resistance of the black matrix BM is 10 ^N Ω · cm or more, and the specific resistance of the black matrix BM is 10 M
When written as 10 ^M and 10 ^M Ω · cm or more and, N>
9, and M> 6. Or N> 13,
It is desirable that the relationship satisfy M> 7.

It is also desirable to use a resin composition as a material for forming the black matrix from the viewpoint of reducing the surface reflection of the liquid crystal display device.

Further, as compared with the case where a metal film such as Cr is used for the black matrix, an etching process of the metal film is not required, so that the manufacturing process of the color filter substrate can be simplified. When a metal film is used, the manufacturing steps are: 1) metal film formation, 2) resist coating, 3) exposure, 4) development, 5)
Metal film etching, 6) resist stripping.

On the other hand, when a resin is used,
1) resin application, 2) exposure, and 3) development, and the process can be significantly shortened.

However, the resin composition has a lower light-shielding property than a metal film. Increasing the thickness of the resin improves the light-shielding properties, but increases the variation in the thickness of the black matrix. This means that, for example, when there is a thickness variation of ± 10%, when the thickness of the black matrix is 1.0 μm, ± 0.1 μm,
This is because when it is 2 μm, it becomes ± 0.2 μm.

When the thickness of the black matrix is increased, the variation in the thickness of the color filter substrate increases, and it becomes difficult to improve the gap accuracy of the liquid crystal display substrate.
For the above reasons, it is desirable that the thickness of the resin is 2 μm or less.

In order to increase the OD value to about 4.0 or more at a film thickness of 1 μm, for example, when blackening by increasing the carbon content, the specific resistance of the black matrix BM is about 10 ⁶
Ω · cm or less and cannot be used at present. OD
The value can be defined as the value obtained by multiplying the extinction coefficient by the film thickness.

For this reason, in this embodiment, the light shielding film BM
Is formed of a resin composition obtained by mixing a black inorganic pigment into a resist material, and is formed to a thickness of about 1.3 ± 0.1 μm. Examples of the inorganic pigment include palladium and electroless plated Ni. Further, the specific resistance of the black matrix BM was set to about 10 ⁹ Ω · cm, and the OD value was set to about 2.0.

The calculation results of the light transmission amount when this resin composition black matrix BM is used are shown below.

OD value = log (100 / Y) Y = ∫A (λ) · B (λ) · C (λ) dλ / ∫A (λ)
C (λ) dλ Here, A is the visibility, B is the transmittance, C is the light source spectrum, and λ is the wavelength of the incident light.

When light is shielded by a film having an OD value of 2.0, Y = 1% is obtained from the above equation (1), and the incident light intensity is 4000 cd /
Assuming m ² , about 40 cd / m ² of light will be transmitted. This light intensity is sufficiently bright to be visually recognized by humans.

The light-shielding film BM is also formed in a frame shape in the peripheral portion, and its pattern is a pattern in which a plurality of openings are provided in a dot shape as shown in FIG.
Are formed continuously with the pattern of the matrix section shown in FIG.

<< Color Filter FIL >> The color filter FIL is formed in a stripe shape by repeating red, green and blue at a position facing the pixel. The color filter FIL is formed so as to overlap the edge portion of the light shielding film BM.

In the present invention, the plane layout of the overlapping portion is defined. Details will be described later.

The color filter FIL can be formed, for example, as follows. First, the upper transparent glass substrate SU
A dye base such as an acrylic resin is formed on the surface of B2, and the dye base other than the red filter formation region is removed by photolithography. Thereafter, the dyed base material is dyed with a red dye and subjected to a fixing treatment to form a red filter R. Next, the green filter G,
Blue filters B are sequentially formed.

<< Overcoat Film OC >> The overcoat film OC is provided to prevent the dye of the color filter FIL from leaking to the liquid crystal LC and to flatten the steps formed by the color filter FIL and the light shielding film BM. The overcoat film OC is formed of, for example, a transparent resin material such as an acrylic resin or an epoxy resin.

[0091] The liquid crystal layer and the polarizing plate Subsequently, the liquid crystal layer, orientation film, described polarizing plate or the like.

<< Liquid Crystal Layer >> As the liquid crystal material LC, the dielectric anisotropy Δ △ is positive and its value is 13.2, and the refractive index anisotropy Δn
Is 0.081 (589 nm, 20 ° C.), a dielectric anisotropy Δ △ is negative and the value is −7.3, and a refractive index anisotropy Δn is 0.053 (589 nm, 20 ° C.). The nematic liquid crystal of C) was used.

The thickness (gap) of the liquid crystal layer was more than 2.8 μm and less than 4.5 μm when the dielectric anisotropy Δ △ was positive.
This is because the retardation Δn · d exceeds 0.25 μm.
When it is less than 32 μm, a dielectric constant characteristic having almost no wavelength dependence within the visible light range is obtained, and most of the liquid crystal having a positive dielectric anisotropy Δ △ has a birefringence anisotropy Δn of 0. 0.07 or more
This is because it is less than 09.

On the other hand, when the dielectric anisotropy Δ △ was negative, the thickness (gap) of the liquid crystal layer was more than 4.2 μm and less than 8.0 μm. This is because, like the liquid crystal having a positive dielectric anisotropy Δε, the retardation Δn · d exceeds 0.25 μm by 0.32 μm.
Most of the liquid crystal having a negative dielectric anisotropy Δ △ has a birefringence anisotropy Δn of more than 0.04 to suppress the dielectric anisotropy Δ △ is negative.
This is because it is less than 6.

Further, the maximum transmittance can be obtained when the liquid crystal molecules are rotated by 45 ° from the rubbing direction to the electric field direction by a combination of an alignment film and a polarizing plate described later. The thickness (gap) of the liquid crystal layer is controlled by polymer beads.

The liquid crystal material LC is not particularly limited as long as it is a nematic liquid crystal. Dielectric anisotropy △ ε
The larger the value, the lower the driving voltage, and the smaller the refractive index anisotropy Δn, the smaller the thickness (gap) of the liquid crystal layer.
Can be made thicker, the liquid crystal filling time can be shortened, and the gap variation can be reduced.

<< Orientation Film >> Polyimide is used as the orientation film ORI. The rubbing direction RDR is parallel to each other between the upper and lower substrates, and the angle φLC between the applied electric field direction EDR and the angle φLC.
Is 75 °. FIG. 11 shows the relationship.

The rubbing direction RDR and the applied electric field direction E
The angle with DR is 45 ° or more and less than 90 ° when the dielectric anisotropy △ ε of the liquid crystal material is positive, and is more than 0 ° and 45 ° or less when the dielectric anisotropy △ ε is negative. Is fine.

<< Polarizing Plate >> G1220DU (trade name) manufactured by Nitto Denko Corporation was used as the polarizing plate POL. As shown in FIG. 11, the polarization transmission axis MAX1 of the lower polarizing plate POL1 was used.
With the rubbing direction RDR, and the upper polarizer POL
The polarization transmission axis MAX2 is orthogonal to it.

As a result, it is possible to obtain a normally closed characteristic in which the transmittance increases as the voltage applied to the pixel of the present invention (the voltage between the pixel electrode PX and the counter electrode CT) increases.

Further, in the liquid crystal display device referred to as the in-plane switching method disclosed in the present invention, when a high potential such as static electricity is applied from outside the surface on the upper substrate SUB2 side, display abnormalities occur. . Therefore, a layer of a transparent conductive film having a sheet resistance of 1 × 10 ⁸ Ω / □ or less is formed further above or on the surface of the upper polarizing plate POL2, or a sheet resistance of 1 × is provided between the polarizing plate and the transparent substrate. I of 10 ⁸ Ω / □ or less
Forming a layer of a transparent conductive film such as TO, or mixing conductive particles such as ITO, SnO ₂ , and In ₂ O _{3 with} the adhesive layer of the polarizing plate to reduce the sheet resistance to 1 × 10 ⁸ Ω / □ or less. It becomes necessary. Regarding this measure, it is not publicly known, but in Japanese Patent Application No. 7-264443 filed by the same applicant,
There is a detailed description of the improvement of the shield function.

<< Configuration around Matrix >> FIG. 12 shows a display panel PNL including upper and lower glass substrates SUB1 and SUB2.
2 is a plan view of a main part around a matrix (AR) of FIG. FIG. 13 shows an external connection terminal GTM to which a scanning circuit is connected on the left side.
It is sectional drawing of a vicinity.

In the manufacture of this panel, if the size is small, a plurality of devices are simultaneously processed on a single glass substrate and then divided in order to improve the throughput. If the size is large, the manufacturing equipment is shared. For each type, a glass substrate of a standardized size is processed and then reduced to a size suitable for each type. In each case, the glass is cut after passing through a single process.

FIGS. 12 and 13 show examples of the latter.
12 and 13, the upper and lower substrates SUB1 and SUB2 are used.
LN indicates the edge of both substrates before cutting. In any case, in the completed state, the external connection terminal group T
The size of the upper substrate SUB2 is limited to the inside of the lower substrate SUB1 so that g, Td, and the terminal CTM are present (the upper side and the left side in the figure) so as to expose them.

The terminal groups Tg and Td are respectively a scanning circuit connection terminal GTM and a video signal circuit connection terminal DT described later.
M and a plurality of lead wiring portions are collectively named for a unit of a tape carrier package TCP (see FIGS. 14 and 13) on which the integrated circuit chip CHI is mounted.

The lead wiring from the matrix section of each group to the external connection terminal section is inclined as approaching both ends. This is because the display panel P is set in the arrangement pitch of the package TCP and the connection terminal pitch in each package TCP.
This is for adjusting to the terminals DTM and GTM of the NL.

The counter electrode terminal CTM is connected to the counter electrode CT.
Is a terminal for applying a counter voltage from the outside. The counter electrode signal line CL in the matrix portion is connected to a scanning circuit terminal GTM.
, And the common voltage signal lines are grouped together by a common bus line CB to form a common electrode terminal CT
M.

Between the transparent glass substrates SUB1 and SUB2, along the edges thereof, except for the liquid crystal filling opening INJ, the liquid crystal L
A seal pattern SL is formed so as to seal C.
The sealing material is made of, for example, an epoxy resin.

The layers of the alignment films ORI1 and ORI2 are formed inside the seal pattern SL. Polarizing plates POL1, P
OL2 is formed on the outer surfaces of the lower transparent glass substrate SUB1 and the upper transparent glass substrate SUB2, respectively.

The etching LC is sealed in a region partitioned by the seal pattern SL between the lower alignment film ORI1 and the upper alignment film ORI2 for setting the direction of the liquid crystal molecules.
The lower alignment film ORI1 is formed above the protective film PSV1 on the lower transparent glass substrate SUB1 side.

In this liquid crystal display device, various layers are separately stacked on the lower transparent glass substrate SUB1 side and the upper transparent glass substrate SUB2 side, and the seal pattern SL is formed on the substrate SUB2.
Side, the lower transparent glass substrate SUB1 and the upper transparent glass substrate SUB2 are overlapped with each other to form a seal pattern SL
The liquid crystal LC is injected from the opening INJ, the inlet INJ is sealed with an epoxy resin or the like, and the upper and lower substrates are cut to be assembled.

<< Equivalent Circuit of Entire Display Device >> FIG. 15 is a schematic explanatory diagram of peripheral circuits of a liquid crystal display device according to the present invention.
As shown in the figure, the liquid crystal display substrate is constituted by a set of a plurality of pixels in which an image display unit is arranged in a matrix,
Each pixel is configured to independently control the modulation of transmitted light from a backlight disposed behind the liquid crystal display substrate.

An active pixel area is provided on an active matrix substrate SUB1, which is one of the components of the liquid crystal display substrate.
The gate signal line GL and the counter voltage signal line CL, which extend in the x direction (row direction) and are arranged in parallel in the y direction (column direction), extend in the y direction while being insulated from the AR, and extend in the x direction. The provided drain signal line DL is formed.

Here, a unit pixel is formed in a rectangular area surrounded by each of the gate signal line GL, the counter voltage signal line CL, and the drain signal line DL.

The liquid crystal display substrate is provided with a vertical scanning circuit V and a video signal driving circuit H as external circuits, and the vertical scanning circuit V sequentially supplies a scanning signal (voltage) to each of the gate signal lines GL. From the video signal drive circuit H to the drain signal line DL in accordance with the timing.
Is supplied with a video signal (voltage).

The vertical scanning circuit V and the video signal driving circuit H are supplied with power from the liquid crystal driving power supply circuit 3 and input image information from the CPU 1 after being divided into display data and control signals by the controller 2 respectively. It is supposed to be.

<< Driving Method >> FIG. 16 is a driving waveform diagram of the liquid crystal display device of the present invention. The opposite voltage is VCH and VCL.
Value AC rectangular wave and the scanning signal VG
(I-1) The non-selection voltage of VG (i) is changed by two values of VCH and VCL every scanning period. The amplitude width of the counter voltage and the amplitude value of the non-selection voltage are the same.

The video signal voltage is a voltage obtained by subtracting half of the amplitude of the counter voltage from the voltage to be applied to the liquid crystal layer.

The counter voltage may be DC, but by converting it to AC, the maximum amplitude of the video signal voltage can be reduced, and a video signal drive circuit (signal-side driver) having a low withstand voltage can be used.

<< Function of Storage Capacitance Cstg >> Storage Capacitance Cs
tg is written to the pixel (thin film transistor TFT
Is provided for long storage of video information (after the power is turned off).

In the method of applying an electric field parallel to the substrate surface used in the present invention, unlike the method of applying the electric field perpendicular to the substrate surface, the capacitance (the so-called liquid crystal capacitance) formed by the pixel electrode and the counter electrode is different. Since there is almost no storage, the storage Cstg is an essential component.

The storage capacitor Cstg also functions to reduce the effect of the gate potential change ΔVg on the pixel electrode potential Vs when the thin film transistor TFT switches. This situation is represented by the following equation.

ΔVs = [Cgs / (Cgs + Cstg +
Cpix)] × ΔVg where Cgs is a parasitic capacitance formed between the gate electrode GT and the source electrode SDI of the thin film transistor TFT,
Cpix represents a capacitance formed between the pixel electrode PX and the counter electrode CT, and ΔVs represents a change in pixel electrode potential due to ΔVg, a so-called feedthrough voltage.

This change ΔVs causes a DC component applied to the liquid crystal LC, but the value can be reduced as the storage capacitance Cstg is increased.

The reduction of the DC component applied to the liquid crystal LC is as follows.
It is possible to improve the life of the liquid crystal LC and reduce so-called burn-in in which a previous image remains when the liquid crystal display screen is switched.

As described above, since the gate electrode GT is made large so as to completely cover the i-type semiconductor layer AS, the area of overlap with the source electrode SDI and the drain electrode SD2 increases, and therefore the parasitic capacitance Cgs increases. The pixel electrode potential Vs has an adverse effect of being easily affected by the gate (scanning) signal Vg. However, the storage capacity Cs
By providing tg, this disadvantage is also eliminated.

<< Manufacturing Method >> Next, a method of manufacturing the above-described liquid crystal display device on the substrate SUB1 side will be described.

FIG. 17, FIG. 18 and FIG. 19 are explanatory views of the manufacturing process of the liquid crystal display device according to the present invention. In FIG. 17, the central characters are the abbreviations of the process names. The right side of the thin film transistor TFT portion shown in the drawing shows the flow of processing viewed from the cross-sectional shape near the gate terminal. Also,
Except for Step B and Step D, Step A to Step I are divided corresponding to each photographic process (photolithography), and any cross-sectional view of each process is a stage where the processing after the photographic process is completed and the photoresist is removed. Is shown.

In the present invention, photographic processing refers to a series of operations from application of a photoresist, through selective exposure using a mask to development of the photoresist, and a repetitive description will be omitted. Description will be given below according to the divided steps.

Step A (FIG. 17) A 300 nm thick Al-Pd or Al-Pd is formed on a lower transparent glass substrate SUB1 made of AN635 glass (trade name).
Conductive film g made of W, Al-Ta, Al-Ti-Ta, etc.
1 is provided by sputtering. After the photographic processing, the conductive film g1 is selectively etched with a mixed acid solution of phosphoric acid, acid and glacial acetic acid. Thereby, the gate electrode GT, the scanning signal line GL, the counter electrode CT, the counter voltage signal line CL, and the electrode PL
1, gate terminal GTM, first conductive layer of common bus line CB, first conductive layer of counter electrode terminal CTM, gate terminal GT
An anodizing bus line SHg (not shown) connecting M and an anodizing pad (not shown) connected to the anodizing bus line SHg are formed.

Step B (FIG. 17) After forming the anodic oxidation mask AO by direct writing, a solution in which 3% tartaric acid was adjusted to PH 6.25 ± 0.05 with ammonia and diluted 1: 9 with ethylene glycol solution was used. The substrate SUB1 is immersed in an anodic oxidizing solution to adjust the formation current density to 0.5 mA / cm ² (constant current formation).

Next, anodic oxidation is performed until the formation voltage 125 V required for obtaining a predetermined alumina (Al ₂ O ₃ ) film thickness is reached. Thereafter, it is desirable to maintain this state for several tens of minutes (constant voltage formation). This is a uniform Al ₂ O
_This is important for obtaining _three films. Thereby, the conductive film g1 is anodized, and the gate electrode GT and the scanning signal line G
L, counter electrode CT, counter voltage signal line CL and electrode PL1
An anodic oxide film AOF having a thickness of 180 bnm is formed thereon.

Step C (FIG. 17) A transparent conductive film g2 made of an ITO film having a thickness of 140 nm is provided by sputtering. After the photographic processing, the transparent conductive film g2 is selectively etched with a mixed acid solution of hydrochloric acid and nitric acid as an etchant, thereby forming the uppermost layer of the gate terminal GTM, the drain terminal DTM, and the second conductive film of the counter electrode terminal CTM. I do.

Step D (FIG. 18) Ammonia gas, silane gas, and nitrogen gas are introduced into the plasma CVD apparatus to form a 220-nm-thick Si nitride film, and silane gas and hydrogen gas are introduced into the plasma CVD apparatus to form a film. After an i-type amorphous Si film having a thickness of 200 nm is provided, a silane gas, a hydrogen gas, and a phosphine gas are introduced into a plasma CVD apparatus to form an N (+)-type amorphous Si film having a thickness of 30 nm.

Step E (FIG. 18) After the photographic processing, the N (+)-type amorphous Si film and the i-type amorphous Si film are selectively etched using SF6 as a dry etching gas, whereby i An island of the type semiconductor layer AS is formed.

Step F (FIG. 18) After the photo processing, the Si nitride film is selectively etched using SF6 as a dry etching gas.

Step G (FIG. 19) A conductive film d1 made of Cr having a thickness of 60 nm is provided by sputtering, and an Al-P film having a thickness of 400 nm is further formed.
A conductive film d2 made of d, Al-Si, Al-Ta, Al-Ti-Ta, or the like is provided by sputtering. After the photographic processing, the conductive film d2 is etched with the same liquid as in Step A,
The conductive film d1 is etched with a ceric ammonium nitrate solution, and the video signal line DL, the source electrode SD1, the drain electrode SD2, the pixel electrode PX, the electrode PL2, the second conductive layer, the third conductive layer and the drain of the common bus line CB are formed. Terminal D
A bus line SHd (not shown) for short-circuiting TM is formed. Next, SF6 is introduced into the dry etching apparatus,
By etching the N (+) type amorphous Si film,
The N (+) type semiconductor layer d0 between the source and the drain is selectively removed.

Step H (FIG. 19) An ammonia gas, a silane gas, and a nitrogen gas are introduced into a plasma CVD apparatus to form a 500-nm-thick Si nitride film. After photographic processing, SF is used as the drain etching gas.
The protective film PSV1 is formed by selectively etching the Si nitride film by a photolithography technique using No. 6.

<< Display Panel PNL and Drive Circuit Board PCB
1 >> FIG. 20 is a top view showing a state where the display panel PNL, the video signal driving circuit H, and the vertical scanning circuit V shown in FIG. 12 are connected.

CH1 is a drive IC chip for driving the display panel PNL (the lower five are drive ICs on the vertical scanning circuit side).
Chip, drive ICs on the left side of the 10 video signal drive circuits
Chip). TCP is a tape carrier package in which the driving IC chip CH1 is mounted by a tape automated bonding (TAB) method as shown in FIGS. 14 and 13, and PCB1 is a driving circuit in which the above-described TCP, capacitors and the like are mounted. The substrate is divided into two, one for a video signal drive circuit and one for a scan signal drive circuit.

FGP is a frame ground pad.
A spring-shaped fragment provided by cutting into the shield case SHD is soldered. FC is the lower drive circuit board PC
This is a flat cable for electrically connecting B1 to the left drive circuit board PCB1.

As shown in the figure, the flat cable FC is formed by sandwiching and supporting a plurality of lead wires (phosphor bronze material plated with Sn) with a striped polyethylene layer and a polyvinyl alcohol layer. use.

<< Connection Structure of TCP >> FIG.
FIG. 13 is a diagram showing a cross-sectional structure of a tape carrier package in which an integrated circuit chip CHI constituting a scanning signal driving circuit V and a video signal driving circuit H is mounted on a flexible wiring board, and FIG. FIG. 3 is a cross-sectional view of a main part showing a pair connected to a scanning signal circuit terminal GTM.

In the figure, TTB is an input terminal / wiring portion of the integrated circuit CHI, and TTM is an output terminal / wiring portion of the integrated circuit CHI, which is made of, for example, Cu. The bonding pads PAD of the integrated circuit CHI are connected to the leads by a so-called face-down bonding method.

The outer ends (commonly called outer leads) of the terminals TTB and TTM are respectively connected to the semiconductor integrated circuit chips CH
Corresponds to input and output of I, CRT /
Anisotropic conductive film AC for TFT conversion circuit / power supply circuit SUP
F connects to the liquid crystal display panel PNL.

[0146] The package TCP is connected to the panel PNL so that the tip end covers the protective film PSV1 exposing the connection terminal GTM on the panel PNL side. Therefore,
Since the outer connection terminal GTM (DTM) is covered with at least one of the protective film PSV1 and the package TCP, the outer connection terminal GTM (DTM) is resistant to electric contact.

BF1 is a base film made of polyimide or the like, and SRS is a solder resist film for masking so that the solder does not stick to unnecessary portions during soldering. The gap between the upper and lower glass substrates outside the seal pattern SL is protected by an epoxy resin EPX or the like after cleaning, and the space between the package TCP and the upper substrate SUB2 is further filled with a silicon resin SIL to multiplex protection.

<< Drive Circuit Board PCB2 >> Drive Circuit Board P
The CB2 has electronic components such as an IC, a capacitor, and a resistor mounted thereon. The drive circuit board PCB2 includes a power supply circuit for obtaining a plurality of divided and stabilized voltage sources from one voltage source, and a CR (Crystal Control Unit) from a host (upper processing unit).
A circuit SUP including a circuit for converting information for T (cathode ray tube) into information for a TFT liquid crystal display device is mounted. C
J is a connector connection portion to which a connector (not shown) connected to the outside is connected.

Drive Circuit Board PCB1 and Drive Circuit Board PC
B2 is electrically connected by a joiner JN such as a flat cable FC.

<< Overall Configuration of Liquid Crystal Display Module >> FIG.
Is an exploded perspective view showing each component of the liquid crystal module, SHD is a frame-shaped shield case (metal frame) made of a metal plate, WD is its display window, PNL is a liquid crystal display panel, SPS is a light diffusion plate, GLB is a light guide, RFS is a reflection plate, BL is a fluorescent tube of a backlight, MCA is a lower case (backlight case), and each member is stacked in a vertical arrangement relationship as shown in the figure to obtain a module MD.
L is assembled.

The module MDL is a shield case SHD
The whole is fixed by the claws and hooks provided on the rim. Here, the housing MD is a module MDL.
And the backlight case MCA.

The backlight case MCA has a shape that houses the backlight fluorescent tube BL, the light diffusion plate SPS, the light guide GLB, and the reflection plate RFS. The backlight case MCA is disposed on the side of the light guide GLB. Light from tube BL to light guide G
A uniform backlight is formed on the display surface by the LB, the reflection plate RFS, and the light diffusion plate SPS, and the light is emitted toward the liquid crystal display panel PNL.

The backlight fluorescent tube BL is connected to an inverter circuit board, and serves as a power supply for the backlight fluorescent tube BL.

Embodiment 1 FIG. 1 is a schematic sectional view of one pixel showing the structure of a first embodiment of the liquid crystal display device according to the present invention.

A first substrate (TFT substrate) SUB1, which is an active matrix substrate, is made of a glass substrate, and the counter electrode CT and the pixel electrode PX are formed on the TFT substrate SUB1.
Are arranged in different layers by the gate insulating film GI.

The pixel electrode P is provided on the substrate via a TFT.
A video signal line DL for supplying a video signal to X is arranged. A polarizing plate is arranged on the surface of the first substrate SUB1 opposite to the surface on which the wiring is formed.

On the other hand, the second substrate SUB2, which is a color filter substrate, expresses a color with a black matrix BM for blocking unnecessary leakage light and preventing the TFT from being irradiated with external light. A color filter layer FIL composed of red, green, and blue is formed, and an overcoat film OC is formed thereon.

On the surface of the second substrate SUB2 opposite to the surface on which the black matrix BM and the like are formed, a polarizing plate POL is provided.
2 is affixed.

Both the TFT substrate (first substrate) SUB1 and the color filter substrate (second substrate) SUB2 are provided with alignment films ORI1 and ORI respectively at the interface in contact with the liquid crystal layer LC.
2 are formed.

The feature of this embodiment lies in the layout of the video signal line DL and the color filter layer FIL. That is, in the present embodiment, the video signal line DL and the color filter layer FIL are configured to overlap when viewed from a direction perpendicular to the plane of the substrate. In this embodiment, the overlap amount OL1 between the video signal line DL and the color filter layer FIL is 2 μm.
As the overlap amount OL1 is larger, the margin at the time of overlapping (joining) the TFT substrate and the color filter substrate can be improved.

FIG. 2 is a schematic sectional view of one pixel of a liquid crystal display device having a conventional structure for explaining the effect of this embodiment.

In this conventional structure, the color filter layer FI
Although L is configured to overlap the black matrix BM, the color filter layer FIL does not overlap with the video signal line DL when viewed from a direction perpendicular to the plane of the substrate, and has a layout separated by an interval NL. ing.

In the liquid crystal display device of the horizontal electric field type, the above structural difference greatly affects the characteristics of vertical smear. In the case of a vertical electric field type liquid crystal display device, vertical smear is generated due to parasitic capacitance between a wiring and a pixel electrode. However, in the case of the horizontal electric field type liquid crystal display device, vertical smear does not occur due to the parasitic capacitance but occurs in the following two modes.

That is, one of them is that the video signal line DL and the pixel electrode PX are affected by the supply voltage of the video signal line DL.
And an electric field is generated between the pixel electrodes PX and the counter electrode CT. The other is light leakage from between the video signal line DL and the counter electrode CT. This is because the liquid crystal molecules are rotated by the electric field generated between the video signal line DL and the counter electrode CT to generate transmitted light.

Most of this transmitted light is a black matrix B
Although the light is shielded by M, light leakage occurs because the OD value of the resin material constituting the black matrix BM is insufficient. In particular, in the case of a horizontal electric field type liquid crystal display device,
When a metal material is used for the black matrix BM, the effective electric field intensity applied to the liquid crystal molecules is reduced, thereby increasing the driving voltage.

Therefore, a resin material capable of realizing high resistance is generally used as the material of the black matrix for the horizontal electric field. Since the resin material has a lower OD value than the metal material, there is a problem in the light shielding characteristics. The former video signal line D
The influence of the leakage electric field from L can be reduced by optimally designing the electrode width between the video signal line DL and the counter electrode CT on the TFT substrate. However, the latter effect of light leakage requires the development of materials and the like, and countermeasures are difficult.

FIG. 3 is a schematic diagram of a display screen showing an example of an evaluation pattern of vertical smear, in which a white display window pattern is displayed at the center of the screen and the background color is black.

Here, in this evaluation, the width of the window in the vertical direction was set to 幅 of the width Y in the vertical direction of the screen. At the evaluation points shown in the figure, the luminance difference between when the window pattern is displayed and when it is not displayed is evaluated.

When the luminance when the window pattern is displayed at the evaluation point is A and the luminance when the window pattern is not displayed is B, the intensity of the vertical smear is (A−
B) / B × 100 (%).

Table 1 shows the evaluation results of the vertical smear of this example.

[0171]

[Table 1]

As shown in Table 1, the strength of the vertical smear of the conventional structure was 6
It can be seen that, in contrast to 0%, in the case of the structure of the present embodiment, it could be reduced to 10%.

The method of manufacturing the structure of this embodiment is the same as that of the conventional structure, so that the number of manufacturing steps does not need to be increased.

Embodiment 2 FIG. 4 is a schematic sectional view of one pixel showing the structure of a liquid crystal display according to a second embodiment of the present invention.

The outline of the configuration of the present embodiment is the same as that of the first embodiment (FIG. 1), and the description thereof will be omitted.

This embodiment is characterized in that the black matrix B
The color filter layers FIL adjacent to each other on M are overlapped. In this embodiment, the overlap width OL2 between the adjacent color filter layers is 2 μm.

When the vertical smear of the liquid crystal display device of this embodiment is evaluated by the same method as in the first embodiment, the same result as in the first embodiment (Table 1) is obtained. This is because, when looking at the structure on the color filter substrate side corresponding to between the video signal line DL and the counter electrode CT, the substrate SUB2, the black matrix BM,
This is because it is composed of the color filter layer FIL and the overcoat film OC, and has the same structure as that of the first embodiment.

In this embodiment, there is no increase in the number of manufacturing steps.

<< Embodiment 3 >> FIG. 5 is a schematic sectional view of one pixel showing the structure of a liquid crystal display device according to a third embodiment of the present invention. In FIG. 1, the cross section of one pixel and the counter electrode of an adjacent pixel are shown. Since the outline of the configuration is the same as that of the first embodiment (FIG. 1), the description is omitted.

The present embodiment is characterized in that the color filter layer FI
L is configured to overlap with the counter electrode CT of the adjacent pixel. With such a structure, the video signal line D
Looking at the structure on the color filter substrate SUB2 side corresponding to between L and the counter electrode CT, the structure includes the substrate SUB2, the black matrix BM, the color filter layer FIL, and the overcoat film OC.

Therefore, as compared with the first embodiment (FIG. 1) and the second embodiment (FIG. 4), it is possible to further reduce the leakage light generated between the video signal line DL and the counter electrode CT. .

Table 2 shows the evaluation results of the vertical smear in the structure of this example.

[0183]

[Table 2]

Since this evaluation method is the same as that in the first embodiment, the description is omitted. For reference, the evaluation result of the vertical smear of the conventional structure shown in FIG. 2 is also shown.

From Table 2, it can be seen that the vertical smear in the case of the conventional structure is 6
In contrast to 0%, the structure of the present embodiment can reduce it to 8%.

The strength of the vertical smear of this embodiment is 1 in Embodiment 1.
The reduction from 0% to 8% is due to the fact that the film contributing to the light shielding between the video signal line DL and the counter electrode CT is increased by one color filter layer. Also, in this embodiment, there is no increase in the number of manufacturing steps.

Embodiment 4 FIG. 6 is a schematic sectional view of one pixel showing the structure of a fourth embodiment of the liquid crystal display device according to the present invention. Since the outline of the configuration of the present embodiment is the same as that of the first embodiment (FIG. 1), the description is omitted.

The present embodiment is characterized in that a B (blue) color filter material is provided on a black matrix BM formed at the boundary between R (red) and G (green) pixels, and the G and B pixels Is to form an R color filter material on the black matrix BM formed at the boundary of the pixel and a G color filter material on the black matrix BM formed at the boundary between the B and R pixels.

The evaluation result of the vertical smear in this structure is the value shown in Table 2 as in the third embodiment. This is because the cross-sectional structure of the color filter substrate SUB2 corresponding to between the video signal line DL and the counter electrode CT is the same as that of the third embodiment.

In this embodiment, the number of manufacturing steps does not increase.

[0191]

As described above, according to the present invention,
It is possible to obtain a high-quality liquid crystal display device with improved light-shielding properties of a backlight leakage light generated between a video signal wiring and a counter electrode of a horizontal electric field type liquid crystal display device, effectively reducing vertical smear. it can.

[Brief description of the drawings]

FIG. 1 is a schematic cross-sectional view of one pixel showing a configuration of a first embodiment of a liquid crystal display device according to the present invention.

FIG. 2 is a schematic cross-sectional view of one pixel of a liquid crystal display device having a conventional structure for explaining the effect of the first embodiment of the liquid crystal display device according to the present invention.

FIG. 3 is a schematic diagram of a display screen showing an example of an evaluation pattern of vertical smear.

FIG. 4 is a schematic cross-sectional view of one pixel showing the configuration of a second embodiment of the liquid crystal display device according to the present invention.

FIG. 5 is a schematic sectional view of one pixel showing a configuration of a third embodiment of the liquid crystal display device according to the present invention.

FIG. 6 is a schematic cross-sectional view of one pixel showing the configuration of a fourth embodiment of the liquid crystal display device according to the present invention.

FIG. 7 is a plan view showing one pixel of an active matrix type color liquid crystal display device of the present invention, a light shielding region of a black matrix BM, and its periphery.

8 is a sectional view of the thin film transistor TFT taken along the line 4-4 in FIG. 7;

9 is a diagram showing a storage capacitance Cstg along a line 5-5 in FIG. 7;
FIG.

10A and 10B are a cross-sectional view of the vicinity of an electrode of one pixel and a cross-sectional view of a peripheral portion of the substrate in an image display area of a liquid crystal display substrate of a horizontal electric field type.

FIG. 11 is an explanatory diagram of a rubbing direction and an electric field direction of an alignment film.

FIG. 12 is a plan view of a main part around a matrix (AR) of a display panel PNL including upper and lower glass substrates SUB1 and SUB2.

FIG. 13 shows an external connection terminal G connected to a scanning circuit on the left side.
It is sectional drawing of TM vicinity.

FIG. 14 is an explanatory diagram of a sectional structure of an output side and an input side of a gate TCP.

FIG. 15 is a schematic explanatory diagram of a peripheral circuit of a liquid crystal display device according to the present invention.

FIG. 16 is a driving waveform diagram of the liquid crystal display device of the present invention.

FIG. 17 is an explanatory diagram of the manufacturing process of the liquid crystal display device according to the present invention.

FIG. 18 is an explanatory diagram of the manufacturing process of the liquid crystal display device according to the present invention.

FIG. 19 is an explanatory diagram of a manufacturing process of the liquid crystal display device according to the present invention.

20 is a top view illustrating a state where the display panel PNL, the video signal driving circuit H, and the vertical scanning circuit V illustrated in FIG. 12 are connected.

FIG. 21 is an exploded perspective view showing each component of the liquid crystal module.

[Explanation of symbols]

TFT Thin film transistor AS Amorphous silicon film GL Scan signal line DL Video signal line BM Black matrix PX Pixel electrode CT Counter electrode CL Counter voltage signal line Cstg Storage capacitance d0 N (+) type semiconductor layer d1 First conductive film d2 Second conductivity Film SD1 Source electrode SD2 Drain electrode GI Gate insulating film GT Gate electrode AOF Anodized film of gate electrode SUB1 Lower transparent glass substrate (active matrix substrate: TFT substrate: first substrate) PL1 Storage capacitor lower electrode SUB2 Upper transparent glass substrate (Color filter substrate:
POL1, POL2 ... Polarizing plate FIL Color filter layer OC Overcoat film LC Liquid crystal E Electric field SL Sealing material ORI1, ORI2 Alignment film PSV1 Passivation film RDR Rubbing direction EDR Applied electric field direction MAX1, MAX2 Transmission axis of polarizing plate PNL Display panel CTM Terminal connection part Tg, Td External connection terminal group LN Board size before cutting CB Common bus line INJ Liquid crystal sealing port BFI Base film SRS Solder resist film EPX Epoxy resin FGP Frame ground pad PCB Drive circuit board TTB Integrated circuit CHI Input terminal / wiring section FC flat cable TTM Output terminal / wiring section of integrated circuit CHI.

Continued on the front page (72) Inventor Shigeru Matsuyama 3300 Hayano Mobara-shi, Chiba Pref.Electronic Device Division, Hitachi, Ltd. (72) Inventor Masayuki Hikiba 3300 Hayano, Mobara-shi, Chiba Pref.

Claims (5)

[Claims] A plurality of scanning signal lines and video signal lines; a switching element formed near an intersection of the scanning signal line and the video signal line; and a pixel electrode to which a drive voltage is applied via the switching element. A first substrate constituting an active matrix substrate including a counter electrode arranged so as to apply an electric field substantially parallel to the plane of the substrate together with the pixel electrode, a black matrix formed of a resin composition, A liquid crystal composition is sandwiched between a second substrate constituting a color filter substrate on which a color filter layer arranged corresponding to a pixel is formed, and a plane of each substrate is interposed between the pixel electrode and a counter electrode. In a liquid crystal display device that performs image display by changing the light transmittance of the liquid crystal composition by an electric field component generated substantially in parallel, a direction perpendicular to the plane of each substrate is used. A liquid crystal display device characterized in that the video signal wiring and at least a part of the color filter layer are arranged so as to overlap when viewed. 2. A plurality of scanning signal lines and video signal lines, a switching element formed near an intersection of the scanning signal line and the video signal line, and a pixel electrode to which a driving voltage is applied via the switching element. A first substrate comprising an active matrix substrate comprising a counter electrode disposed so as to apply an electric field substantially parallel to the plane of the substrate together with the pixel electrode, a black matrix comprising a resin composition, A liquid crystal composition is sandwiched between a second substrate constituting a color filter substrate on which a color filter layer arranged corresponding to a pixel is formed, and a plane of each substrate is interposed between the pixel electrode and a counter electrode. In a liquid crystal display device that performs image display by changing the light transmittance of the liquid crystal composition by an electric field component generated substantially in parallel, a direction perpendicular to the plane of each substrate is used. A liquid crystal display device, wherein, when viewed, an end of a color filter layer in a direction parallel to the video signal wiring is arranged inside a line width of the video signal wiring. 3. A plurality of scanning signal lines and video signal lines, a switching element formed near an intersection of the scanning signal line and the video signal line, and a pixel electrode to which a driving voltage is applied via the switching element. A first substrate comprising an active matrix substrate comprising a counter electrode disposed so as to apply an electric field substantially parallel to the plane of the substrate together with the pixel electrode, a black matrix comprising a resin composition, A liquid crystal composition is sandwiched between a second substrate on which a color filter layer arranged corresponding to a pixel is formed, and a liquid crystal composition is generated between the pixel electrode and a counter electrode in substantially parallel with the plane of each substrate. In a liquid crystal display device which performs image display by changing the light transmittance of the liquid crystal composition by an electric field component, color filter layers adjacent in a direction parallel to the scanning signal line are mutually separated. A liquid crystal display device which is arranged so as to overlap on the black matrix. 4. A plurality of scanning signal lines and video signal lines, a switching element formed near an intersection of the scanning signal line and the video signal line, and a pixel electrode to which a driving voltage is applied via the switching element. A counter electrode disposed so as to apply an electric field substantially parallel to the plane of the substrate together with the pixel electrode, and one of the pixel electrode and the counter electrode is disposed in parallel with the video signal wiring. A liquid crystal composition is sandwiched between a first substrate constituting an active matrix substrate and a second substrate having a black matrix composed of a resin composition and a color filter layer arranged corresponding to each pixel. Performing image display by changing the light transmittance of the liquid crystal composition by an electric field component generated substantially in parallel with the plane of each substrate between the pixel electrode and the counter electrode. In the liquid crystal display device, when viewed from a direction perpendicular to the plane of each of the substrates, an end of the color filter layer in a direction parallel to the video signal wiring is arranged adjacent to and parallel to a video signal wiring in an adjacent pixel. A liquid crystal display device, which is arranged inside the width of the pixel electrode or the counter electrode. 5. A plurality of scanning signal lines and video signal lines, a switching element formed near an intersection of the scanning signal line and the video signal line, and a pixel electrode to which a driving voltage is applied via the switching element. A counter electrode disposed so as to apply an electric field substantially parallel to the plane of the substrate together with the pixel electrode, and one of the pixel electrode and the counter electrode is disposed in parallel with the video signal wiring. A liquid crystal composition is sandwiched between a first substrate constituting an active matrix substrate and a second substrate having a black matrix composed of a resin composition and a color filter layer arranged corresponding to each pixel. Performing image display by changing the light transmittance of the liquid crystal composition by an electric field component generated substantially in parallel with the plane of each substrate between the pixel electrode and the counter electrode. In crystal display device, a color filter material having a chromaticity different from that of the adjacent color filter layer, and formed on at least a part of the black matrix, wherein the video signal lines and disposed opposite,
In addition, an end of the color filter material in a direction parallel to the video signal wiring is arranged inside a width of the pixel electrode or the counter electrode arranged adjacent to and parallel to the video signal wiring. Liquid crystal display device.