JP2741769B2 - Liquid crystal display - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

 [Industrial Application Field] The present invention relates to, for example, a thin film transistor and a pixel electrode.
Active matrix method as one component of pixel
Related to liquid crystal display devices such as color liquid crystal display devices
is there. [Prior art] Conventional active matrix liquid crystal display
In, as shown in JP-A-61-151516,
ITO for scanning signal lines, gate electrodes, and electrode films for storage capacitors
(Indium tin oxide) film.
The electrode film of the capacitance element is branched from the scanning signal line. In addition, black matrix
A configuration for improving contrast by providing
It is known from 46626. In addition, a thin film transistor using a black matrix
JP-A-61-38931, JP-A-61-105583
It is known from the gazette. However, in each of the known examples, the storage capacitor element and the black mat
I do not focus on the relationship with Rix. [Problems to be Solved by the Invention] However, in such a liquid crystal display device, an ITO film
The sheet resistance of the scanning signal line is large
Therefore, it becomes impossible to write a signal to the pixel electrode. Therefore, the scanning signal lines, gate electrodes,
It is conceivable that the pole film is composed of a chromium film.
The scanning signal line and the electrode film of the storage capacitor are formed integrally.
And the scanning signal at the intersection of the scanning signal line and the video signal line.
Line and the video signal line have a large overlapping area.
The number of shorts between the test signal line and the video signal line increases,
Retention becomes worse. In addition, the scanning signal line and the electrode film of the storage capacitor
When configured with, the electrode film of the storage capacitor element is connected to the scanning signal line.
When branching off from the
The image becomes dark. Also, use a light-shielding metal such as a chrome film
When formed with a film, the black matrix
However, there is a problem that the aperture ratio is reduced when the cover is covered with the filter. The present invention has been made to solve the above problems.
Signal writing to the pixel electrode
Liquid crystal display device with good yield and bright image
It is an object to provide a liquid crystal display device. [Means for Solving the Problems] To achieve the above object, the present invention provides
A storage capacitor is provided at a portion where the elementary electrode and the scanning signal line overlap,
The scanning signal line is formed of a metal film, and the storage capacitance is black.
It is characterized by being exposed from the matrix. [Operation] In this liquid crystal display device, a holding container having a light shielding property is provided.
Retained because the amount is exposed from the black matrix
The capacitance electrode also contributes to the contour of the pixel,
Compared to completely covering the volume with black matrix.
The mouth ratio can be increased. In addition, amorphous silicon with high photoconductive
By applying the present invention to the liquid crystal display device used for the layers,
To prevent the thin film transistor from malfunctioning due to external light.
Can be stopped. Also, by using a chrome film for the scanning signal line,
Resistance can be reduced, and signal writing to the pixel electrode
Be faster. In addition, one color filter and the adjacent color filter
The black matrix between the
-The contrast of the displayed image is improved. In addition, the black matrix and color filter
By overlapping, black matrix and color
There is no misalignment of the filter. [Embodiment] Active matrix system to which the present invention is applied
FIG. 2 shows one pixel of the liquid crystal display section of the color liquid crystal display device of FIG.
(Main part plan view), cut along the II-II section line in FIG.
The cross section is shown in FIG. FIG. 4 (plan view of main part)
Is a main part of a liquid crystal display unit in which a plurality of pixels shown in FIG. 2 are arranged.
Is shown. As shown in FIGS. 2 to 4, the liquid crystal display device has a lower part.
A thin film is placed on the inner surface (liquid crystal side) of the transparent glass substrate SUB1.
A pixel having a transistor TFT and a transparent pixel electrode ITO
It is configured. The lower transparent glass substrate SUB1 is 1.
The thickness is about 1 mm. Each pixel has two adjacent scanning signal lines (gate signal lines).
Or horizontal signal line) GL and two adjacent video signal lines
(Drain signal line or vertical signal line) In the intersection area with DL
(Within a region surrounded by four signal lines).
The scanning signal lines GL are arranged in columns as shown in FIGS.
And a plurality of them are arranged in the row direction. Video signal
The line DL extends in the row direction and is arranged in a plurality in the column direction.
I have. The thin film transistor TFT of each pixel has 3
(Multiple) thin film transistors
Transistor) consisting of TFT1, TFT2 and TFT3.
Each of the thin film transistors TFT1 to TFT3 is substantially the same.
One size (same channel length and width)
You. That of this divided thin film transistor TFT1 to TFT3
Each is mainly composed of gate electrode GT, insulating film GI, i-type (intrinsic, in
trinsic, not doped with conductivity type determining impurities)
I-type semiconductor layer AS made of silicon (Si), a pair of source electrodes
It is composed of a pole SD1 and a drain electrode SD2. In addition,
The source / drain originally depends on the bias polarity between them.
The polarity of this liquid crystal display device is in operation
Since the source and drain are reversed during operation,
I want to be understood. However, in the following explanation, one is
And the other is fixed as drain. The gate electrode GT is formed as shown in FIG.
As shown in detail in the main part plan view), from the scanning signal line GL
Projects in the row direction (downward in FIGS. 2 and 5)
(T-shaped branch)
). That is, the gate electrode GT is substantially connected to the video signal line DL.
Is configured to extend in parallel with Gate electrode GT
Are the formation areas of the thin film transistors TFT1 to TFT3, respectively.
It is configured to protrude up to Thin film transistor
The gate electrodes GT of TFT1 to TFT3 are integrated (common
The same scanning signal line
It is formed continuously to GL. Gate electrode GT is a thin film transistor.
A large step should be formed in the transistor TFT formation region.
The first conductive film g1 is formed as a single layer so as not to be formed. No.
1 The conductive film g1 is made of, for example, chromium formed by sputtering.
A (Cr) film is formed with a thickness of about 1100 [Å]. This gate electrode GT is shown in FIG. 2, FIG. 3 and FIG.
As shown, completely cover the i-type semiconductor layer AS.
It is formed larger (as viewed from below). But
Therefore, a bag such as a fluorescent lamp is placed below the lower transparent glass substrate SUB1.
This opaque Cr gate electrode when fitted with Krite
GT becomes a shadow and the semiconductor layer AS is backlit
However, the above-mentioned conduction phenomenon caused by light irradiation, that is, TFT
The characteristics are less likely to deteriorate. The gate electrode GT book
The size is between the source and drain electrodes SD1 and SD2.
(Minimum required for gate electrode and source / drain
Width (including allowance for pole alignment) and channel
The depth length that determines the width W is between the source and drain electrodes
To the distance (channel length) L, ie, the mutual conductor
How many factors W / L determine the reactance gm
Is determined. The size of the gate electrode in this liquid crystal display device is
Of course, it is made larger than the original size described above. Only from the gate electrode GT's gate and light shielding function side
Considering that, the gate electrode GT and its wiring GL are a single layer
It may be formed integrally, in this case as an opaque conductive material
Al containing Si, pure Al, and Al containing Pd
You can choose. The scanning signal line GL is formed on the first conductive film g1 and on the first conductive film g1.
A composite film composed of the second conductive film g2 provided.
You. The first conductive film g1 of the scanning signal line GL is connected to the gate electrode.
Formed in the same manufacturing process as the first conductive film g1 of the pole GT, and
The body is made up. The second conductive film g2 is formed, for example, by sputtering.
900-4000 using aluminum (Al) film formed by
It is formed with a film thickness of about [Å]. The second conductive film g2 has a scanning signal
To reduce the resistance of signal line GL and increase the signal transmission speed (pixel
Information writing characteristics).
ing. Also, the scanning signal line GL is smaller than the width of the first conductive film g1.
Thus, the width of the second conductive film g2 is reduced. Sand
That is, the scanning signal line GL has a stepped shape on its side wall.
The surface of the insulating film GI on top of it.
It is configured so that it can be supported. The insulating film GI is provided for each of the thin film transistors TFT1 to TFT3.
Used as a gate insulating film. Insulating film GI is the gate
It is formed above the electrodes GT and the scanning signal lines GL. Absolute
The edge film GI is, for example, a silicon nitride film formed by plasma CVD.
And formed with a film thickness of about 3000 [用 い]. As mentioned above
In addition, the surface of the insulating film GI is the same as that of the thin film transistors TFT1 to TFT3.
In each forming area and scanning signal line GL forming area
Is flattened. The i-type semiconductor layer AS is formed as shown in FIG.
As shown in detail in the main part plan view),
Channel formation area of each of the thin film transistors TFT1 to TFT3
Used as an area. Thin film transistor divided into several parts
Each i-type semiconductor layer AS of TFT1 to TFT3 is
In one piece. That is, the pixel division
Each of the plurality of thin film transistors TFT1 to TFT3,
Consisting of island regions of one (common) i-type semiconductor layer AS
I have. The i-type semiconductor layer AS is an amorphous silicon film or
Formed with a crystalline silicon film and formed with a film thickness of about 1800 [Å]
I do. This i-type semiconductor layer AS is made of Si_ThreeN
_FourThe same plasma CVD is performed successively after the formation of the insulating film GI made of
Device and without exposing it to the outside
Is done. Also, dope P for ohmic contact
N⁺The type semiconductor layer d0 (FIG. 3) is also continuously
It is formed to a thickness of [Å]. After that, the lower transparent glass
Substrate SUB1 is taken out of the CVD equipment and photo processing technology
By N⁺Semiconductor layer d0 and i-type semiconductor layer AS
As shown in Fig. 3, Fig. 3 and Fig. 6,
Turned. In this way, the thin-film transistor divided into a plurality of pixels
Each i-type semiconductor layer AS of TFT1 to TFT3 is integrated
By doing so, each of the thin film transistors TFT1 to TFT3
The common drain electrode SD2 is connected to the i-type semiconductor layer AS (actually,
Is the film thickness of the first conductive film g1, N⁺Thickness of the semiconductor layer d0 and
Step corresponding to the film thickness obtained by adding the film thickness of the i-type semiconductor layer AS
Difference) from the drain electrode SD2 side to the i-type semiconductor layer AS side.
The drain electrode SD2 is disconnected.
Probability of occurrence of point defects is reduced.
be able to. In other words, in this liquid crystal display,
When the electrode SD2 climbs over the step of the i-type semiconductor layer AS.
Point defects occurring in the element can be reduced to one third. Also, although different from the layout of this liquid crystal display device, i
The video signal line DL directly passes over the semiconductor layer AS,
The excess video signal line DL is used as the drain electrode SD2.
If the video signal line DL (drain electrode SD2) is an i-type
Generation of line defects due to disconnection when going over the semiconductor layer AS
The probability of occurrence can be reduced. In other words, multiple pixels
Each of thin-film transistors TFT1 to TFT3 divided into numbers
By integrating the i-type semiconductor layer AS of
Line DL (drain electrode SD2) is once on i-type semiconductor layer AS
Because you can only get over it.
Two times at the end of the ride). The i-type semiconductor layer AS is described in detail in FIG. 2 and FIG.
As shown, the intersection of the scanning signal line GL and the video signal line DL
(Crossover part)
I have. The extended i-type semiconductor layer AS is located at the intersection.
To reduce the short circuit between the scanning signal line GL and the video signal line DL.
Is configured. Thin-film transistor TFT1 to TFT3 divided into multiple pixels
The source electrode SD1 and the drain electrode SD2 of the
2, 3 and 7 (necessary in a predetermined manufacturing process)
As shown in detail in FIG.
They are provided separately from each other. Source electrode SD1, drain
Each of the in-electrodes SD2 changes the bias polarity of the circuit
So that the source and drain are interchangeable in operation.
Has been established. In other words, a thin film transistor TFT is
Similarly, it is bidirectional. Each of the source electrode SD1 and the drain electrode SD2 is N⁺Type
From the lower side in contact with the semiconductor layer d0, the first conductive film d1, the second conductive film d1,
The conductive film d2 and the third conductive film d3 are sequentially superposed.
I have. The first conductive film d1, the second conductive film d2 and the
And the third conductive film d3 are the same as each of the drain electrodes SD2.
It is formed in one manufacturing process. For the first conductive film d1, a chromium film formed by sputtering is used.
A film thickness of 500 to 1000 [Å] (in this liquid crystal display,
(Thickness of about 00 [Å]). Chromium film
If it is formed thickly, the stress increases, so 2000 [Å]
It is formed in a range that does not exceed a certain thickness. Chrome film is N⁺
Good contact with the mold semiconductor layer d0. Chromium film will be described later
Of the second conductive film d2 to be N⁺Type semiconductor layer d0
A so-called barrier layer that prevents scattering is formed. First
As the conductive film d1, in addition to the chromium film, a high melting point metal (Mo,
Ti, Ta, W) film, refractory metal silicide (MoSi)_Two, TiS
i_Two, TaSi_Two, WSi_Two) It may be formed of a film. After patterning the first conductive film d1 by photo processing, the same
Using a mask for photo processing or using the first conductive film d1 as a mask
N⁺The type semiconductor layer d0 is removed. That is, the i-type semiconductor layer
N left on AS⁺Type semiconductor layer d0 is a layer other than the first conductive film d1.
Portions are removed by self-alignment. At this time, N⁺Mold half
The conductor layer d0 is etched so that the entire thickness is removed.
Therefore, the i-type semiconductor layer AS is also slightly etched on its surface.
However, the degree may be controlled by the etch time. Thereafter, the second conductive film d2 is formed by sputtering aluminum.
Film thickness of 3000-5500 [Å] (with this liquid crystal display
Is formed to a thickness of about 3500 [Å]. Alminium
The film is less stressed and thicker than the chromium film.
The source electrode SD1 and the drain electrode
The configuration is such that the resistance values of the pole SD2 and the video signal line DL are reduced.
Has been established. The second conductive film d2 is a thin film transistor TFT
Operation speed and signal transmission speed of video signal line DL
Is configured to be able to achieve high speed. One
That is, the second conductive line d2 improves the writing characteristics of the pixel.
Can be. As the second conductive film d2, other than the aluminum film
With silicon (Si), copper (Cu) and palladium (Pd)
It may be formed of an aluminum film contained as an additive.
No. After patterning the second conductive film d2 by the photo processing technique,
A transparent conductive film (ITO:
Nesa film) and a film thickness of 1000 to 2000 [Å]
In the display device, the thickness is about 1200 [Å]. This
The third conductive film d3 has a source electrode SD1, a drain electrode SD2 and
And video signal lines DL, and transparent pixel electrodes IT
O is configured. The first conductive film d1 of the source electrode SD1 and the first conductive film d1 of the drain electrode SD2
Each of the first conductive films d1 is an upper second conductive film d2 and a second conductive film d2.
3 Larger size on the channel formation region side than the conductive film d3
It consists of. That is, the first conductive film d1 is the first conductive film
Manufacturing process between d1, second conductive film d2 and third conductive film d3
Even if the mask misalignment occurs in the second step, the second conductive film d2 and
And a size larger than the third conductive film d3 (the first conductive film d1 to
Each channel formation region side of the third conductive film d3 is on the
(May be a line). Source
First conductive film d1 of electrode SD1, first conductive film of drain electrode SD2
Each of d1 is the gate length L of the thin film transistor TFT.
It is configured to prescribe. In this way, the thin-film transistor divided into a plurality of pixels
In the TFT1 to TFT3, the source electrode SD1 and the drain electrode S
The channel forming region side of each first conductive film d1 of D2 is
2 Larger size than the conductive film d2 and the third conductive film d3
By configuring, the source electrode SD1 and the drain electrode SD2
Between the first conductive film d1 and the thin film transistor
The gate length L of the TFT can be defined. 1st conductivity
The separation dimension (gate length L) between the films d1 depends on the processing accuracy (pattern
Thinning)
The gate length L of each of the transistors TFT1 to TFT3 is made uniform.
Can be As described above, the source electrode SD1 is connected to the transparent pixel electrode ITO.
It is connected. The source electrode SD1 is connected to the i-type semiconductor layer AS.
Step shape (film thickness of first conductive film g1, N⁺Film thickness of semiconductor layer d0
And the film thickness of the i-type semiconductor layer AS.
Along the steps). Specifically, the source
The electrode SD1 is formed along the step shape of the i-type semiconductor layer AS.
The first conductive film d1 and the first conductive film d1
Smaller side connected to transparent pixel electrode ITO compared to
And a second conductive film d2 formed by
And a third conductive film d3 connected to the first conductive film d1
ing. The first conductive film d1 of the source electrode SD1 is N⁺Type semiconductor
Good adhesion to the layer d0, and mainly the second conductive film d2
It is configured as a barrier layer against these diffused substances. Seo
The second conductive film d2 of the source electrode SD1 is made of chromium of the first conductive film d1.
The film cannot be formed thick due to increased stress, and the i-type semiconductor layer
This i-type semiconductor can't get over the step shape of AS
Configured to get over layer AS. That is, the second
The conductive film d2 is formed to be thick to provide step coverage.
Has improved. Since the second conductive film d2 can be formed thick,
Resistance value of source electrode SD1 (drain electrode SD2 and video signal line
The same applies to DL). Third
The conductive film d3 is caused by the i-type semiconductor layer AS of the second conductive film d2.
Since it is not possible to get over the step shape, the second conductive film
First conductive film dd1 exposed by reducing the size of d2
It is configured to be connected to. First conductive film d1 and third conductive film d1
The conductive film d3 not only has good adhesion, but also
The connection is small, so the connection can be made securely.
it can. Thus, the source electrode SD1 of the thin film transistor TFT
Are formed at least along the i-type semiconductor layer AS.
A first conductive film d1 as a layer and an upper portion of the first conductive film d1
And has a smaller specific resistance value than the first conductive film d1,
And a second conductive film d2 smaller in size than the first conductive film d1.
And the first conductive film exposed from the second conductive film d2.
A third conductive film d3, which is a transparent pixel electrode ITO, is connected to d1.
And by. Thin film transistor TFT and transparent pixel electrode ITO
Since the connection can be made securely, the discontinuity caused by the disconnection
Depression can be reduced. Moreover, the source electrode SD1
Is a barrier effect of the first conductive film d1 and has a small resistance value.
Second conductive film d2 (aluminum film) can be used
Therefore, the resistance value can be reduced. The drain electrode SD2 is formed integrally with the video signal line DL.
And are formed in the same manufacturing process. Drain electrode
SD2 is an L-shaped projecting in the column direction that intersects with the video signal line DL
It has a shape. That is, it is divided into a plurality of pixels
Of each of the thin film transistors TFT1 to TFT3
The pole SD2 is connected to the same video signal line DL. The transparent pixel electrode ITO is provided for each pixel.
This constitutes one of the pixel electrodes of the liquid crystal display section. Transparent pixel
The electrode ITO is a thin film transistor T divided into a plurality of pixels.
Three transparent pixel electrodes corresponding to each of FT1 to TFT3
(Divided transparent pixel electrode) divided into ITO1, ITO2 and ITO3
ing. The transparent pixel electrode ITO1 is a thin film transistor TFT1
Connected to source electrode SD1. Transparent pixel electrode ITO2
Is connected to the source electrode SD1 of the thin film transistor TFT2.
ing. The transparent pixel electrode ITO3 is a thin film transistor TFT3
Connected to source electrode SD1. Each of the transparent pixel electrodes ITO1 to ITO3 is a thin film transistor.
As in the case of each of the TFT1 to TFT3,
It is composed of Each of transparent pixel electrodes ITO1 to ITO3
This corresponds to the i-type half of each of the thin film transistors TFT1 to TFT3.
The conductor layer AS is integrally configured (each divided
The thin film transistor TFT is concentrated in one place.
Therefore, it is configured in an L-shape. In this manner, two adjacent scanning signal lines GL and two adjacent scanning signal lines GL
Of pixels arranged in the intersection area with the two video signal lines DL
A thin film transistor TFT is divided into a plurality of thin film transistors TFT1 to T
FT3, and the thin-film transistor T
Transparent pixel electrode ITO divided into multiple parts for each of FT1 to TFT3
Pixel division by connecting each of 1 to ITO3
(For example, thin film transistor TFT1)
A pixel is not a point defect as a whole
(Thin film transistors TFT2 and TFT3 are not point defects)
So that point defects as a whole pixel can be reduced
You. Further, some of the point defects obtained by dividing the pixel are
Small compared to the total area (in this liquid crystal display,
(One-third of the area of the pixel)
Can be Further, the transparent pixel electrodes ITO1 to ITO3 obtained by dividing the pixels.
Each having substantially the same size.
Therefore, the area of the point defect in the pixel can be made uniform. Further, the transparent pixel electrodes ITO1 to ITO3 obtained by dividing the pixels.
Each having substantially the same size.
Transparent pixel electrode and common transparent pixel with each of ITO1 to ITO3
Liquid crystal capacitance (Cpix) composed of electrodes ITO
Is added to each of the transparent pixel electrodes ITO1 to ITO3.
Of transparent pixel electrodes ITO1 to ITO3 and gate electrode GT
And the overlapping capacity (Cgs) generated by
Wear. In other words, each of the transparent pixel electrodes ITO1 to ITO3
Crystal volume and superposition volume can be made uniform
This marks the liquid crystal molecules of the liquid crystal LC caused by this superposition capacity.
The DC component to be added can be made uniform.
When the method of canceling the DC component of
The variation of the DC component applied to the crystal
You. On the thin film transistor TFT and the transparent pixel electrode ITO,
A protective film PSV1 is provided. The protective film PSV1 is mainly a thin film
Formed to protect the transistor TFT from moisture, etc.
Use a material that is highly transparent and has good moisture resistance.
You. The protective film PSV1 is made of, for example, an acid formed by plasma CVD.
5000 to 11000
[Å] film thickness (about 8000 [Å] in this liquid crystal display device)
(Film thickness). Outside of the protective film PSV1 on the thin film transistor TFT,
I-type semiconductor layer in which light is used as a channel forming region
A shielding film LS is provided so as not to be incident on the AS.
As shown in FIG. 2, the shielding film LS is a region surrounded by a dotted line.
Is configured within. The shielding film LS has a light shielding property.
High, for example, made of aluminum film or chromium film
And is formed to a thickness of about 1000 [Å] by sputtering. Therefore, the common semiconductor of the thin film transistors TFT1 to TFT3
The body layer AS consists of upper and lower light shielding films LS and a large gate electrode
Sandwiched by GT, outside natural light or back
The light will not hit. The light shielding film LS and the gate electrode GT
It is larger than the semiconductor layer AS and is formed in a shape similar to it,
Both are assumed to be almost the same size.
The gate electrode GT is drawn smaller than the light shielding film LS
). The backlight is placed on the upper transparent glass substrate SUB2 side.
And attach the lower transparent glass substrate SUB1 to the observation side (external
Side), in which case the light shielding film LS
The gate electrode GT of the light source functions as a light shield for natural light. The thin-film transistor TFT has a positive via on the gate electrode GT.
The source-drain channel resistance
When the bias decreases to zero, the channel resistance increases.
It is configured to work. In other words, the thin film transistor
The star TFT controls the voltage applied to the transparent pixel electrode ITO.
It is configured to: The liquid crystal LC consists of a lower transparent glass substrate SUB1 and an upper transparent glass
In the space formed between the substrate and SUB2, the orientation of the liquid crystal molecules
Specified for lower alignment film ORI1 and upper alignment film ORI2
It is enclosed. The lower alignment film ORI1 protects the lower transparent glass substrate SUB1 side.
It is formed on the film PSV1. On the inner (liquid crystal side) surface of the upper transparent glass substrate SUB2
Indicates the color filter FIL, protective film PSV2,
The pole (COM) ITO and the upper alignment film ORI2 are sequentially laminated
Is provided. The common transparent pixel electrode ITO has a lower transparent glass substrate SUB
Opposite and adjacent to the transparent pixel electrode ITO provided for each pixel on one side
Other common transparent pixels in contact with the electrode ITO
I have. The common transparent pixel electrode ITO has a common voltage Vcom
Is applied. Common voltage Vcom
Is a low-level drive voltage Vd applied to the video signal line DL.
 min and the high level drive voltage Vd max.
You. The color filter FIL is made of a resin material such as acrylic resin.
The dyed base material is formed by coloring a dye.
The color filter FIL is placed at the position facing the pixel for each pixel.
It is composed and dyed separately. That is, color
The filter FIL is, like the pixel, the two adjacent scanning signals.
Signal line GL and the adjacent two video signal lines DL
It is configured. Each pixel is an individual color filter FIL
Are divided into a plurality of parts in the predetermined color filter. The color filter FIL can be formed as follows.
it can. First, a dye group was applied to the surface of the upper transparent glass substrate SUB2.
Material is formed and red filter type by photolithography technology
The dyed substrate other than the formation area is removed. After this, the dyed substrate is
Dye with red dye, fixation process, form red filter R
To achieve. Next, by performing a similar process, the green
A filter G and a blue filter B are sequentially formed. Thus, each color filter of the color filter FIL is
By forming it in the intersection area facing the pixel,
-The scanning signal line GL and the video signal
Since each of the image signal lines DL exists,
Equivalent to each pixel and each color filter of color filter FIL
To secure the alignment margin with the data (alignment margin
Can be increased). In addition, color filters
When forming each color filter of FIL,
Alignment margin dimensions can be secured. That is, in this liquid crystal display device, two adjacent running lines
Intersection area between the scanning signal line GL and two adjacent video signal lines DL
Within the pixel, divide this pixel into multiple
The color filters of the color filter FIL are
By forming, the above-mentioned point defects can be reduced.
And the alignment margin between each pixel and each color filter
Dimensions can be secured. The protective film PSV2 changes the color filter FIL to a different color.
To prevent the dye that has been dyed from leaking into the liquid crystal LC
Is provided. The protective film PSV2 is, for example, an acrylic resin
It is formed of a transparent resin material such as fat or epoxy resin. This liquid crystal display device has a lower transparent glass substrate SUB1 side and an upper
Each layer on the transparent glass substrate SUB2 side is formed separately
After that, the lower transparent glass substrate SUB1 and the upper transparent glass substrate
Superimpose the board SUB2 and fill the liquid crystal LC between them
It is assembled. As shown in FIG. 4, each pixel of the liquid crystal display section
Multiple lines are arranged in the same column direction as the
Pixel row X₁, X_Two, X_Three, X_Four,…
You. Each pixel row X₁, X_Two, X_Three, X_Four, ... each pixel is
Thin film transistors TFT1 to TFT3 and transparent pixel electrodes ITO1 to
The arrangement position of ITO3 is the same. That is, the pixel column
X₁, X_Three, ... are the thin film transistor TFT1
To TFT3 on the left, transparent pixel electrodes ITO1 to ITO3
The position is configured on the right side. Pixel row X₁, X_Three, ... of that
Next row of pixel columns X in each row direction_Two, X_Four, ... each picture
The element is pixel row X₁, X_Three,... Each pixel
It is composed of pixels arranged symmetrically with respect to the line DL.
You. That is, pixel row X_Two, X_Four, ... each pixel is
Transistor pixels on the right side of TFT1 to TFT3 thin film transistors
The arrangement positions of the electrodes ITO1 to ITO3 are configured on the right side. Soshi
Pixel row X_Two, X_Four,... Each pixel is a pixel row X₁,
X_Three,... For each pixel in the column direction
It is arranged to be moved (shifted). That is, the pixel column
If the pixel interval of X is 1.0 (1.0 pitch), the next image
The element sequence X has a pixel interval of 1.0, and corresponds to the pixel sequence X in the preceding stage.
And is shifted by 0.5 pixel intervals (0.5 pitch) in the column direction. each
The video signal line DL extending between pixels in the row direction is connected to each pixel column X
Half a pixel interval (0.5 pitch) in the row direction.
It is configured to exist. Thus, in the liquid crystal display unit, the thin film transistor
Pixels with the same position of TFT and transparent pixel electrode ITO
A plurality of pixels are arranged in the direction to form a pixel column X, and the next stage of the pixel column X
Of the pixel row X of the preceding stage to the video signal line DL.
It is composed of pixels arranged in line symmetry with respect to
It is configured to be shifted by a half pixel interval with respect to the previous pixel row.
Fig. 8 (Pixel and color filter overlap
Pixels in the previous stage, as shown in
A pixel (for example, an image) in which a predetermined color filter of column X is formed.
Sequence X_ThreePixel on which the red filter R is formed) and the image of the next stage
Pixels in which the same color filter of the element array X is formed (for example,
Pixel row X_FourPixel on which the red filter R is formed) and 1.5
Pixel spacing (1.5 pitch) is possible. Toes
Therefore, the pixels in the previous pixel row X are the pixels in the next nearest pixel row.
Pixels with the same color filter in the elementary row and 1.5 pixels at all times
The color filter is configured to be separated by an interval.
FIL can configure RGB triangle arrangement structure
You. The RGB triangle structure of the color filter FIL
Resolution of color images
The degree can be improved. In addition, the video signal line DL is connected between each pixel column X by a half image.
Since only the elementary interval extends in the column direction, adjacent video signals
Stop crossing Route DL. Therefore, the video signal line DL
Wiring can be eliminated and the occupied area can be reduced,
Eliminate the bypass of the video signal line DL and abolish the multilayer wiring structure
be able to. A circuit diagram of the structure of the liquid crystal display unit is shown in FIG.
(Equivalent circuit diagram of crystal display section). Shown in Figure 10
XiG, Xi + 1G,... Are pixels where the green filter G is formed
Are connected to the video signal line DL. XiB, Xi + 1B, ...
Video signal connected to the pixel where blue filter B is formed
Line DL. Xi + 1R, Xi + 2R, ... are red filters R
This is a video signal line DL connected to a pixel to be formed. these
Is selected by the video signal drive circuit. Yi
Is the pixel column X shown in FIGS. 4 and 8.₁Run to choose
This is the inspection signal line GL. Similarly, each of Yi + 1, Yi + 2, ...
Is the pixel row X_Two, X_ThreeScanning signal line for selecting each of
GL. These scanning signal lines GL are connected to a vertical scanning circuit.
Has been continued. The central part in FIG. 3 shows a cross section of one pixel portion.
On the left, the lower transparent glass substrate SUB1 and the upper transparent glass
Where the external wiring is located at the left edge of the circuit board SUB2
2 shows a cross section of FIG. On the right are the transparent glass substrates SUB1 and
And the right edge of SUB2 where there is no external wiring
It shows a cross section. The sealing material SL shown on each of the left and right sides of FIG.
It is configured to seal the liquid crystal LC, and the liquid crystal filling port
Transparent glass substrates SUB1 and SU excluding (not shown)
It is formed along the entire periphery of the edge of B2. Seal material SL
Is formed of, for example, an epoxy resin. The common transparent pixel electrode IT on the upper transparent glass substrate SUB2 side
O is at least at one location due to the silver paste material SIL.
The external drawer formed on the lower transparent glass substrate SUB1 side
Connected to wiring. This external wiring is
Gate electrode GT, source electrode SD1, drain electrode SD2
Each is formed in the same manufacturing process. The alignment films ORI1 and ORI2, transparent pixel electrode ITO, common
Transparent pixel electrode ITO, protective films PSV1 and PSV2, insulating film GI
Each layer is formed inside the sealing material SL. Polarization
Plate POL consists of lower transparent glass substrate SUB1 and upper transparent glass substrate
It is formed on the outer surface of each of the plates SUB2. Liquid crystal display of another liquid crystal display to which the present invention is applied
One pixel is shown in Fig. 9A (plan view of the main part) and the lower left of the figure.
(Thin film transistor B)
Fig. 9B shows a three-fold enlarged view of the
You. In this liquid crystal display device, each pixel of the liquid crystal display section is
The aperture ratio can be improved and the liquid crystal
Reduces DC component, reduces point defects in liquid crystal display and
Black unevenness can be reduced. This liquid crystal display device is as shown in FIGS. 9A and 9B.
The i-type semiconductor layer AS in each pixel of the liquid crystal display is
Each of the transistors TFT1 to TFT3 is divided. Toes
And the thin film transistors TFT1 to TF divided into a plurality of pixels.
Each of T3 is composed of island regions of independent i-type semiconductor layer AS.
Has been established. The pixel configured in this way extends the video signal line DL.
In the row direction, each of the thin film transistors TFT1 to TFT3
Because they can be evenly distributed and placed,
Transparent pixel electrode IT connected to each of the TFT1 to TFT3
Each of O1 to ITO3 can be configured in a square shape.
Each of the transparent pixel electrodes ITO1 to ITO3 configured in a square shape
Is the direction between adjacent transparent pixel electrodes ITO in the pixel
Area can be reduced in the direction
(Aperture ratio) can be improved. Also, as shown in FIG.
The shape of the transparent pixel electrodes ITO1 to ITO3
When scanning, the scanning signal line GL or the video signal line DL
Line with a sloping angle (for example, a line at a 45 degree angle)
To change. In other words, that of the transparent pixel electrodes ITO1 to ITO3
Each is a line parallel to the scanning signal line GL or the video signal line DL.
Or when the shape is changed with orthogonal lines.
The separation area between the bright pixel electrodes ITO can be reduced.
Thus, the aperture ratio can be improved. Each of the transparent pixel electrodes ITO1 to ITO3 is a thin film transistor.
On the side opposite to the side connected to the transistor TFT
In this case, the signal is superimposed on the next scanning signal line GL in the row direction.
I have. This superposition is performed by the thin film transistors TFT1 to TFT3.
As with the gate electrode GT, a run to select that gate electrode GT
Adjacent to the scanning signal line DL (the scanning signal line DL for selecting pixels)
The scanning signal line DL of the next stage is branched into a T-shape.
I have. The branched scanning signal line GL is a thin film transistor TF.
Like the T gate electrode GT, the first conductive film (chromium film) g1
Of a single layer. The superposition is performed by a transparent pixel electrode.
Each of the poles ITO1 to ITO3 is used as one electrode, and the next scan
The signal line GL was used as a capacitive electrode line and then branched off
Capacitance element (capacitance element) whose part is the other electrode
Configure Cadd. The dielectric film of the storage capacitor Cadd is:
Used as gate insulating film of thin film transistor TFT
It is composed of the same layer as the insulating film GI. The gate electrode GT is the same as the liquid crystal display device shown in FIG.
Is formed larger than the i-type semiconductor layer AS.
In the display device, the thin film transistors TFT1 to TFT3 are independent i
Since it is formed for each type semiconductor layer AS, each thin film transistor
A large pattern is formed for each transistor TFT
Is connected to the branched gate line GL (g1). FIG. 11 shows another layout of the storage capacitance element Cadd.
9A and FIG. 9A.
The equivalent circuit of the pixel described in FIG. 11 and FIG.
Circuit diagram). The storage capacitor Cadd of the pixel shown in FIG.
Are the transparent pixel electrodes ITO1 to ITO3 and the capacitor electrode lines.
With the branched part (the other electrode of the storage capacitor Cadd)
The amount of superposition is increased, and the storage capacity is increased. Base
Basically, the holding capacitance element Cadd shown in FIG.
Is the same as the storage capacitance element Cadd shown in FIG. Fig. 12 Smell
As before, Cgs is the gate of the thin film transistor TFT
Superposition capacitance formed by electrode GT and source electrode SD1
It is. The dielectric film of the superposed capacitance Cgs is the insulating film GI.
You. Cpix is transparent pixel electrode ITO (PIX) and common transparent pixel
This is the liquid crystal capacitance formed between the electrodes ITO (COM). Liquid crystal
The dielectric film with the amount of Cpix is the liquid crystal LC, the protective film PSV1, and the alignment film OR.
I1, ORI2. Vlc is the midpoint potential. The storage capacitor Cadd is formed by a thin film transistor TFT.
When switching, the midpoint potential (pixel electrode potential) Vlc
Acts to reduce the effect of gate potential change ΔVg on
Good. This situation is represented by the following equation. ΔVlc = {(Cgs / (Cgs + Cadd + Cpix))} × ΔVg where ΔVlc represents a change in the midpoint potential due to ΔVg.
You. This change ΔVlc is the cause of the DC component applied to the liquid crystal.
However, if the storage capacitance of the storage capacitor Cadd is increased,
The smaller the value, the smaller the value. Also, the holding capacity
The element Cadd also has the effect of extending the discharge time,
The video information after the transistor TFT is turned off is accumulated for a long time. liquid
The reduction of the DC component applied to the crystal LC improves the life of the liquid crystal LC.
The previous image remains when switching the LCD screen.
Loose seizure can be reduced. As described above, the gate electrode GT completely covers the semiconductor layer AS.
Source / drain electrodes SD
1.The area of overlap with SD2 increases,
The amount Cgs increases and the midpoint potential Vlc becomes the gate (scan) signal Vg
Has the opposite effect of being more susceptible to the effects of But,
This disadvantage can be eliminated by providing the storage capacitor Cadd.
Can be eliminated. Also, the connection between the two scanning signal lines GL and the two video signal lines DL
In a liquid crystal display device having pixels in an intersection area,
Select with one of the two scanning signal lines GL
The thin film transistor TFT of the pixel to be
For each of the divided thin film transistors TFT1 to TFT3
The transparent pixel electrode ITO is divided into multiple parts (ITO1-ITO
3) Connect the divided transparent pixel electrodes ITO1 to ITO3
The pixel electrode ITO is used as one electrode for each of
The other one of the scanning signal lines DL is connected to a capacitor.
The storage capacitor Cadd which is used as a polar line and is used as the other electrode is
By configuring, as described above, the divided pixels
Only part of the pixel becomes a point defect, but the whole pixel is a point defect.
It is possible to reduce pixel point defects because
At the same time as the liquid crystal LC is applied by the storage capacitor Cadd.
Flow component can be reduced, which extends the life of the liquid crystal LC.
Can be up. In particular, by dividing pixels
The gate electrode GT and the source electrode S of the thin film transistor TFT.
Point defects caused by short circuit with D1 or drain electrode SD2
And the transparent pixel electrodes ITO1 to IT
O3 and the other electrode of the storage capacitor Cadd (capacitive
Point defects caused by short-circuit with
You. The point defect on the latter side is one third in the case of this liquid crystal display device.
become. As a result, some of the divided point defects of the pixel
Is smaller than the total area of the pixel,
Can be difficult to see. The storage capacitance of the storage capacitor Cadd is determined by the writing characteristics of the pixel.
From 4 to 8 times the liquid crystal capacitance Cpix (4 · Cpix <Cadd
<8 · Cpix), 8 to 32 times (8
・ Set to a value of about Cgs <Cadd <32 · Cgs). Further, the scanning signal line GL is connected to a first conductive film (chrome film) g1.
Composite film in which the second conductive film (aluminum film) g2 is laminated
And the other electrode of the storage capacitor Cadd, that is, a capacitor.
The branched portion of the electrode wire is connected to one of the composite membranes.
By forming a single-layer film composed of the first conductive film g1,
To reduce the resistance value of the test signal line GL and improve the write characteristics
And the other electrode of the storage capacitor Cadd
Along the stepped portion of the capacitor Cadd
Attach pole (transparent pixel electrode ITO) on insulating film GI
So that the disconnection of one electrode of the storage capacitor Cadd can be
Can be reduced. Also, the other electrode of the storage capacitor Cadd is connected to the first conductive layer of the single layer.
The second conductive film g2 which is composed of the conductive film g1 and is an aluminum film
By not configuring, due to the hillock of the aluminum film
Between the other electrode and one electrode of the storage capacitor Cadd
Can be prevented. Superimposed to form the storage capacitor Cadd
Of each of the transparent pixel electrodes ITO1 to ITO3 and the capacitance electrode line
The part between the forked part and the source electrode SD1
Similarly, when climbing over the step shape of the branched part,
The first conductive film d1 and the first conductive film d1 are connected so that the bright pixel electrode ITO is not disconnected.
And an island region composed of the second conductive film d2.
This island region reduces the area (aperture ratio) of the transparent pixel electrode ITO.
Make it as small as possible so that it does not fall. As described above, one electrode of the storage capacitance element Cadd is connected to the other electrode.
Between the insulating film GI used as the dielectric film of
The specific resistance is smaller than that of the conductive film d1 and the first conductive film d1 formed thereon.
Formed with the second conductive film d2 having a small resistance value and a small size
Forming one of the electrodes (the third conductive film d).
3) the first conductive layer exposed from the second conductive layer d2 of the underlayer.
By connecting to the film d1, the other side of the storage capacitance element Cadd
Ensure that the storage capacitor Cadd along the step based on the electrode
Since one electrode can be bonded, the storage capacitor element
Disconnection of one electrode of the child Cadd can be reduced. A storage capacitor Cadd is provided on the transparent pixel electrode ITO of the pixel.
The liquid crystal display section of the liquid crystal display device is shown in FIG. 14 (liquid crystal display section).
). liquid crystal
The display unit includes pixels, scanning signal lines GL, and video signal lines DL.
It consists of repetition of a unit basic pattern. Capacity
The final scanning signal line GL (or the first
As shown in FIG. 14, the scanning signal lines GL of the stage are common transparent.
Connect to pixel electrode (Vcom) ITO. Common transparent pixel electrode ITO
Is located on the periphery of the liquid crystal display device as shown in FIG.
Is connected to the external wiring by silver paste material SL
ing. In addition, some of the conductive layers (g1
And g2) have the same manufacturing process as the scanning signal line GL
I have. As a result, the final scanning signal line GL (capacitance electrode line)
Can be easily connected to common transparent pixel electrode ITO
You. Thus, the last stage of the capacitor electrode line is connected to the common transparent line of the pixel.
By connecting to bright pixel electrode (Vcom) ITO, the final stage
Capacitor electrode wire is integrated with a part of the conductive layer of the external wiring.
And the common transparent pixel electrode ITO is
Since it is connected to the external lead-out wiring, the final configuration is simple.
Connecting the capacitance electrode line of the step to the common transparent pixel electrode ITO
Can be. In addition, the liquid crystal display device has been applied for
DC cancellation method described in Japanese Patent Application No. 62-95125 (D
Figure 13 (Time chart)
G) to control the drive voltage of the scanning signal line DL
This further reduces the DC component applied to the liquid crystal LC.
Can be In FIG. 13, Vi is an arbitrary scanning signal.
The driving voltage of the line GL, Vi + 1 is the driving voltage of the scanning signal line GL at the next stage.
Dynamic voltage. Vee is the low level applied to the scanning signal line GL.
The bell driving voltages Vd min and Vdd are applied to the scanning signal line GL.
High level driving voltage Vd max. Each time t = t₁~
t_FourVoltage change ΔV of the midpoint potential Vlc (see FIG. 12) at
₁~ ΔV_FourIs the total capacity of the pixels (Cgs + Cpix + Cadd) as C
Then, the following equation is obtained. ΔV₁= − (Cgs / C) · V2 ΔV_Two= + (Cgs / C) · (V1 + V2)-(Cadd / C) · V2 ΔV_Three= − (Cgs / C) · V1 + (Cadd / C) · (V1 + V2) ΔV_Four= − (Cadd / C) · V1 Here, the driving voltage applied to the scanning signal line GL is sufficient.
If you have (below

Note: The DC voltage applied to the liquid crystal LC is expressed by the following equation. ΔV ₃ + ΔV ₄ = (Cadd · V2−Cgs · V1) / C Therefore, if Cadd · V2 = Cgs · V1, the DC voltage applied to the liquid crystal LC becomes zero.

〔The invention's effect〕

As described above, in the liquid crystal display device according to the present invention, since the storage capacitor having the light shielding property is exposed from the black matrix, the aperture ratio is increased as compared with the case where the storage capacitor is completely covered by the black matrix. I can do it. Thus, the effect of the present invention is remarkable.

[Brief description of the drawings]

FIG. 1 is a plan view of a main part in a predetermined manufacturing process of the pixel shown in FIG. 16, and FIG. 2 is an active element to which the present invention is applied.
FIG. 3 is a plan view of an essential part showing one pixel of a liquid crystal display portion of a matrix type color liquid crystal display device. FIG. 3 is a cross-sectional view of a portion cut along a II-II cutting line in FIG. 5 is a plan view of a main part of a liquid crystal display unit in which a plurality of pixels shown in FIG. 2 are arranged, FIGS. 5 to 7 are plan views of a main part in a predetermined manufacturing process of the pixel shown in FIG. 2, and FIG. 4 is a plan view of a main part in a state where the pixel and the color filter shown in FIG.
9A is a plan view of a principal part showing one pixel of a liquid crystal display portion of an active matrix color liquid crystal display device to which the present invention is applied, FIG. 9B is a partially enlarged view thereof, and FIG. FIG. 11 is an equivalent circuit diagram showing a liquid crystal display portion of a matrix type color liquid crystal display device, FIG.
12 is an equivalent circuit diagram of the pixel described in each of FIG. 9A and FIG. 11, FIG. 13 is a time chart showing the driving voltage of the scanning signal line by the DC canceling method, FIG. 14 and FIG. 9A and 9 are equivalent circuit diagrams showing a liquid crystal display portion of the active matrix type color liquid crystal display device shown in FIG. 11, and FIG. 16 is a liquid crystal display portion of the active matrix type color liquid crystal display device according to the present invention. 17a is a cross-sectional view of a portion cut along the line BB of FIG. 16, and FIG. 17b is a cross-sectional view of a portion cut along the line CC of FIG. FIG. 18 is a cross-sectional view of the liquid crystal display device and the periphery of the seal portion of the liquid crystal display device shown in FIG. 16, and FIG.
FIG. 3 is a plan view showing a state in which the pixel shown in the figure and a black matrix pattern are superimposed. SUB: Transparent glass substrate GL: Scan signal line DL: Video signal line GI: Insulating film GT: Gate electrode AS: i-type semiconductor layer SD: Source or drain electrode PSV: Protective film LS: … Light-shielding film LC… Liquid crystal TFT… Thin film transistor ITO (COM)… Transparent pixel electrode g, d… Conductive film Cadd… Holding capacitance element Cgs… Overlapping capacitance Cpix… Liquid crystal capacitance BM… Black matrix pattern

 ──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-59-46626 (JP, A) JP-A-61-38931 (JP, A) JP-A-61-105583 (JP, A) JP-A-2- 63020 (JP, A)

Claims (5)

(57) [Claims] 1. A liquid crystal layer is sandwiched between a first substrate having a plurality of pixel electrodes provided on a transparent substrate and a second substrate having a color filter provided at a position corresponding to each pixel electrode on the first substrate. In the liquid crystal display device, the first substrate is provided so that a plurality of scanning signal lines and a plurality of video signal lines intersect at a plurality of locations, and at the intersection of the scanning signal lines and the video signal lines. Correspondingly, the pixel electrode and the thin film transistor, the thin film transistor is a semiconductor layer made of silicon,
A gate electrode electrically connected to one of the plurality of scanning signal lines, a drain electrode electrically connected to one of the plurality of video signals, and an electrically connected pixel electrode corresponding to the gate electrode; A portion corresponding to the scanning signal line, the video signal line, and the thin film transistor on the second substrate, and completely covers the semiconductor layer of the thin film transistor and external light is applied to the semiconductor layer of the thin film transistor. A black matrix is provided so as to prevent the pixel electrode from hitting, a storage capacitor is provided at a portion where the pixel electrode overlaps a scanning signal line adjacent to the pixel electrode, and the scanning signal line is formed of a light-shielding metal film. The liquid crystal display device, wherein the capacitance is exposed from the black matrix in a plan view when viewed from the second substrate side. 2. The liquid crystal display device according to claim 1, wherein said semiconductor layer is made of amorphous silicon. 3. The liquid crystal display device according to claim 1, wherein said scanning signal line is made of a chromium film. 4. The liquid crystal display device according to claim 1, wherein said black matrix is provided between one color filter and said adjacent color filter. 5. The liquid crystal display device according to claim 4, wherein said black matrix has a portion partially overlapping said color filter.