JPH07199171A - Liquid crystal display device - Google Patents

Abstract

PURPOSE:To provide a liquid crystal display device which reduces the problem or degredation in picture quality due to the step of a light shielding film or a black matrix by selectively providing the light shielding film on the surface of a transparent substrate and burying a transparent resin film in intervals of the light shielding film with the same film thickness as the light shielding film. CONSTITUTION:A liquid crystal panel where a polarizing plate is provided on the outside of a substrate SUB2 is provided, and a black matrix BM consisting of an organic or inorganic light absorbing material and an organic resin is selectively provided on one face of the transparent glass substrate SUB2. A transparent resin film FU is buried in intervals of the black matrix BM with the same film thickness as the black matrix BM to make the transparent resin film FU and the black matrix BM approximately flat, and a color filter FIL is provided on intervals of the black matrix BM, and a transparent picture element electrode and an oriented film are provided on it. Since the black matrix BM and the transparent resin film FU are made approximately flat, the variance in threshold voltage of liquid crystal and the occurrence of domains are reduced.

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 in which a light-shielding film is selectively provided on the surface of a transparent substrate which constitutes a liquid crystal display panel (liquid crystal display element), and in particular, one transparent substrate is black. The present invention relates to a color liquid crystal display device provided with a matrix and a color filter.

[0002]

2. Description of the Related Art Generally, a liquid crystal display device is formed by stacking two transparent glass substrates with a predetermined gap so that the surfaces on which the transparent pixel electrodes for display and the alignment film are laminated face each other. With the frame-shaped sealing material at the edge between,
Attach both substrates, seal the liquid crystal inside the sealing material between both substrates from the liquid crystal sealing port provided in a part of the sealing material, seal it, and install or paste the polarizing plate on the outside of both substrates. A liquid crystal display panel, a backlight arranged below the liquid crystal display panel to supply light to the liquid crystal display panel, a drive circuit board (printed board) arranged outside the outer peripheral portion of the liquid crystal display panel, and It is configured to include a frame-shaped body that is a molded product that holds each member, and a metal frame that houses each of these members and has a liquid crystal display window opened.

FIG. 17 is a cross-sectional view of an essential part of a transparent glass substrate provided with a black matrix and a color filter among two transparent glass substrates constituting a liquid crystal display panel of a conventional liquid crystal display device.

That is, in a color liquid crystal display device, as shown in FIG.
One transparent glass substrate SU of the transparent glass substrates
A black matrix BM for clarifying the contour of each pixel is selectively formed around each pixel on one surface of B2, and a pixel portion (black portion) where the black matrix BM does not exist between the black matrixes BM on the black matrix BM. Red color filter FIL in the opening of the matrix BM)
(R), a green color filter FIL (G), and a blue color filter FIL (B) are sequentially formed. Although not shown, a protective film for the color filter, a transparent pixel electrode, and an alignment film are sequentially formed thereon.

[0005]

Problem to be Solved by the Invention Black Matrix B
After forming M, three color filter FIL (R),
When forming (G) and (B), each color filter F
Even if there is a misalignment between the IL and the black matrix BM, each color filter FIL is adjusted so as not to cause an eye open.
Is formed so that the peripheral edge portion of the black matrix partially overlaps the black matrix BM. Therefore, as shown in FIG.
Due to this overlap, the edge around the color filter FIL becomes high, and a step equivalent to the film thickness of the black matrix BM occurs at the edge. When a liquid crystal display device is assembled using the transparent glass substrate SUB2 having such a step, the step causes unevenness in the thickness of the liquid crystal layer, a difference in the threshold voltage of the liquid crystal, and a domain difference. It is a cause of deterioration of image quality. In particular, when an organic resin film colored in black is used as the material of the black matrix, the problem of reflection due to the reflection of external light on the liquid crystal display screen can be eliminated, but in order to block external light, the black The film thickness of the matrix is required to be 1 to 2 μm, and there is a large step difference as compared with the case where a thin vapor-deposited metal film made of Cr (chrome) or the like is used as the material of the black matrix, and the above-mentioned problem of image quality deterioration becomes large. Particularly, in the case of an active matrix type color liquid crystal display device using a thin film transistor or the like as a switching element, it is necessary to secure an optical density of at least 2.5, preferably at least 3.0, for the black matrix.
If the black matte film is to be formed from the black organic resin film, the film thickness becomes 3 to 5 μm, and an extremely large step is generated, so that the color filter cannot be formed thereon.

An object of the present invention is to provide a liquid crystal display device capable of reducing the problem of image quality deterioration due to the step of the light shielding film or the black matrix.

[0007]

In order to achieve the above object, the present invention provides a liquid crystal display device in which a light shielding film is selectively provided on the surface of a transparent substrate, and a transparent resin film is provided between the light shielding films. It is characterized in that the light-shielding film is embedded with a film thickness almost equal to the film thickness.

More specifically, two transparent glass substrates are stacked with a predetermined gap so that the surfaces on which the transparent pixel electrodes and the alignment film are provided face each other, and the periphery of the edge between the two substrates is laminated. While bonding the both substrates by a frame-shaped sealing material, sealing the liquid crystal inside the sealing material, and having a liquid crystal display panel provided with a polarizing plate outside the both substrates, and, In a liquid crystal display device in which a black matrix made of an organic or inorganic light-absorbing substance and an organic resin is selectively provided on the surface of one of the transparent glass substrates, a transparent resin film is provided between the black matrices to form the black matrix. The black matrix and the transparent resin film are almost flattened by embedding the same thickness, and a color filter is provided between the black matrix and the black matrix. To provide a liquid crystal display device provided with the alignment film and the transparent pixel electrode on top. The thickness of the black matrix made of an organic resin film is about 0.5 to 4 μm.
m.

[0009]

In the liquid crystal display device of the present invention, the space between the selectively provided light-shielding film or black matrix is filled with a transparent resin film with substantially the same thickness, and the light-shielding film or black matrix and the transparent resin film are substantially flattened. Therefore, the variation in the thickness of the liquid crystal layer is reduced, the variation in the threshold voltage of the liquid crystal and the occurrence of domains are reduced, and the problem of image quality deterioration due to the step of the black matrix can be reduced.

[0010]

The invention, further objects of the invention and further features of the invention will be apparent from the following description with reference to the drawings.

Example 1 FIGS. 1 (a) to 1 (d) show a transparent glass substrate on which a black matrix and a color filter of an example of a liquid crystal display device of the present invention are formed. FIG. 3 is a cross-sectional view of main process steps showing a method for manufacturing one transparent glass substrate of the glass substrates).

First, a negative type photosensitive resin film CK-2000 manufactured by Fuji Hunt Technology Co., Ltd., in which a black pigment is dispersed, is formed on a transparent glass substrate SUB2 by a known photolithography technique to have a film thickness of about 1.5 μm. A black matrix BM was formed (FIG. 1 (a)).

Next, a negative transparent photosensitive resin film CT manufactured by Fuji Hunt Technology Co., Ltd. is applied thereon by spin coating or a roll coater so as to have the same film thickness as the black matrix BM, and the transparent resin film FU. After forming, the transparent glass substrate SUB2 was irradiated with ultraviolet rays UV from the back surface to expose the entire surface (FIG. 1 (b)).

Next, when the transparent resin film FU is developed and post-baked, the transparent resin film FU which was slightly present on the black matrix BM is removed, and the black matrix BM has a transparent film of almost the same thickness as the transparent resin film FU. The black matrix BM and the transparent resin film FU were embedded with the resin film FU, and the black matrix BM and the transparent resin film FU were substantially flattened (FIG. 1C). The post-baking is performed to sufficiently cure the transparent resin film FU.

To form a red color filter as the first color filter, a photosensitive red resin film CR-2000 manufactured by Fuji Hunt Technology Co., Ltd. in which a red pigment is dispersed is applied, and then photolithography is performed. By the technique, a portion other than the formation region of the red color filter is removed and patterned to form a red color filter FI.
L (R) was formed. Then, in the same manner, a green color filter F was prepared using a photosensitive green resin film CG-2070 manufactured by Fuji Hunt Technology Co., Ltd. in which a green pigment was dispersed.
Photosensitive blue resin film CB manufactured by Fuji Hunt Technology Co., Ltd. in which IL (G) is formed and then a blue pigment is dispersed.
A blue color filter FIL (B) was formed using -2000 (FIG. 1 (d)).

After that, although not shown, a protective film for the color filter, a transparent pixel electrode, and an alignment film are sequentially formed thereon, and then the alignment film is subjected to alignment treatment to complete the color filter substrate (see FIG. 3).

In this embodiment, the color filter FIL is used.
On the surfaces of (R), (G), and (B), no step due to the conventional black matrix as shown in FIG. 17 was found. Therefore, when the liquid crystal display panel is assembled by combining this transparent glass substrate SUB2 with the other transparent glass substrate (see FIG. 3) on which a thin film transistor, a transparent pixel electrode, an alignment film and the like are formed, a step of the color filter causes It is possible to suppress the phenomenon that the image quality is deteriorated due to unevenness in the thickness of the liquid crystal layer, a difference in the threshold voltage of the liquid crystal, and a domain.

Embodiment 2 In this embodiment, instead of exposing the entire back surface of the transparent resin film FU shown in FIG. 1 (b), a mask for black matrix exposure and a mask of a reversal pattern are used from the front surface of the transparent resin film. The FU was exposed, developed, and prebaked to obtain the state of FIG. Others are the same as in the first embodiment. In this embodiment, the pattern of the transparent resin film FU and the black matrix B are used.
It is necessary to minimize the misalignment with the M pattern.

Example 3 In this example, as shown in FIG. 1 (b), a transparent resin film FU was applied, the entire surface of the transparent glass substrate SUB2 was exposed, and then the surface of the transparent glass substrate SUB2 was polished. Then, the state shown in FIG. Others are the same as in the first embodiment. In this embodiment, the transparent resin film FU need not be a photosensitive resin film, and a thermally crosslinkable transparent resin film can be used, for example.

Although the negative type photosensitive resin film is used in the above embodiment, a positive type photosensitive resin film may be used. For example, when the positive type is used as the photosensitive transparent resin film FU, the transparent resin film FU is exposed using a mask having the same pattern as the mask for black matrix exposure. Further, as the transparent resin film FU, an acrylic resin film or an epoxy resin film other than the above films may be used. In the above-described embodiment, the resin film in which the pigment is dispersed in advance is used to form the black matrix BM and the color filter FIL, but after the colorless resin film is formed by coating,
Each may be colored.

In the present embodiment, since the problem of display deterioration due to the step of the black matrix can be solved, a black matrix using an organic resin film, which must be thick in order to obtain a high light-shielding rate, is used. Can be realized. Therefore, when the transparent glass substrate SUB2 provided with the black matrix BM is on the display screen side (observation side), the inner surface of the transparent glass substrate SUB2 is a black matrix BM occupying a large area of the display screen.
Since an organic resin film is formed instead of a metal film such as Cr, the external light on the display screen side is reflected on the outside of the display screen, making the screen difficult to see (looks like a mirror), reducing the contrast, and displaying quality. Can be suppressed.
In addition, the light of the backlight emitted from the other transparent glass substrate side on which a thin film transistor or the like that is combined with the transparent glass substrate SUB2 is formed is transparent glass substrate S.
The black matrix BM formed on the inner surface of the UB2 reflects the light inward, and the semiconductor layer serving as a channel formation region of the thin film transistor is exposed to light, which causes a conductive phenomenon due to light irradiation.
The problem that the off characteristic of the thin film transistor is deteriorated can be prevented because the black matrix BM is made of an organic resin film and does not reflect light.

<< Active Matrix Liquid Crystal Display Device >>
Embodiments in which the present invention is applied to an active matrix type color liquid crystal display device to which the present invention can be applied will be described below. In the drawings described below, components having the same function are designated by the same reference numeral, and repeated description thereof will be omitted.

<< Outline of Matrix Section >> FIG. 2 is a plan view showing one pixel and its periphery of an active matrix type color liquid crystal display device to which the present invention is applied, and FIG.
-3 is a view showing a section taken along a cutting line, and FIG.
It is sectional drawing in a cutting line.

As shown in FIG. 2, each pixel has two adjacent scanning signal lines (gate signal lines or horizontal signal lines) GL.
And an adjacent two video signal lines (drain signal line or vertical signal line) DL are intersected with each other (in a region surrounded by four signal lines). Each pixel includes a thin film transistor TFT, a transparent pixel electrode ITO1 and a storage capacitor element Cadd. The scanning signal lines GL extend in the left-right direction in the figure, and a plurality of scanning signal lines GL are arranged in the vertical direction. Video signal line DL
Extend in the up-down direction and are arranged in the left-right direction.

As shown in FIG. 3, a thin film transistor TFT and a transparent pixel electrode ITO1 are formed on the lower transparent glass substrate SUB1 side with respect to the liquid crystal layer LC, and a color filter FIL and a light-shielding film are provided on the upper transparent glass substrate SUB2 side. A black matrix pattern BM is formed. Silicon oxide films SIO formed by dipping or the like are provided on both surfaces of the transparent glass substrates SUB1 and SUB2.

On the inner (liquid crystal LC side) surface of the upper transparent glass substrate SUB2, a light shielding film BM and a color filter FI are provided.
L, protective film PSV2, common transparent pixel electrode ITO2 (CO
M) and the upper alignment film ORI2 are sequentially stacked.

<< Outline of Matrix Periphery >> FIG. 5 is a plan view of a main part around the matrix (AR) of the display panel PNL including the upper and lower glass substrates SUB1 and SUB2, and FIG. 6 is a seal corresponding to the upper left corner of the panel of FIG. It is a figure which shows the enlarged plane near the part SL. Further, in FIG. 7, the cross section of FIG. 3 is centered,
The left side is a cross section taken along line 7a-7a in FIG. 6, and the right side is an external connection terminal DTM to which the video signal drive circuit is to be connected.
It is a figure which shows the cross section of the vicinity. Similarly, FIG. 8 is a diagram showing a cross section near the external connection terminal GTM to which the scanning circuit is to be connected on the left side, and a cross section near the seal portion where there is no external connection terminal on the right side.

[0028] Any For this panel In the manufacture of, if small size divided from simultaneously processing a plurality fraction of the device in one glass substrate for increased throughput, manufacturing facilities if large size shared In each type of product, a standardized glass substrate is processed, and then the size is reduced to a size suitable for each product. In each case, the glass is cut after going through one step. 5 and 6 show the latter example. FIG. 5 shows a state after cutting the upper and lower substrates SUB1 and SUB2.
FIG. 6 shows a state before cutting, where LN is the edge of both substrates before cutting, and CT1 and CT2 are the substrates SUB1 and SUB2, respectively.
Indicates the position to be cut. In either case, the size of the upper substrate SUB2 is smaller than the lower substrate SUB1 so that the external connection terminal groups Tg and Td (subscripts omitted) (upper side and left side in the figure) are exposed in the completed state. Is more restricted to the inside. The terminal groups Tg and Td are respectively a scanning circuit connecting terminal GTM and a video signal circuit connecting terminal D, which will be described later.
A plurality of TMs and their lead-out wiring portions are collectively named in units of a tape carrier package TCP (FIGS. 14 and 15) on which an integrated circuit chip CHI is mounted. The lead wiring from the matrix portion of each group to the external connection terminal portion is inclined toward both ends. This is because the arrangement pitch of the package TCP and the connection terminal pitch of each package TCP are equal to the terminals DT of the display panel PNL.
This is to match M and GTM.

Between the transparent glass substrates SUB1 and SUB2, along the edge thereof, except for the liquid crystal filling port INJ, the liquid crystal LC
A seal pattern SL is formed so as to seal the. The sealing material is made of epoxy resin, for example. The common transparent pixel electrode ITO2 on the upper transparent glass substrate SUB2 side is connected to at least one of the lead wirings INT formed on the lower transparent glass substrate SUB1 side by the silver paste material AGP at four corners of the panel in this embodiment. ing. The lead wiring INT is formed in the same manufacturing process as a gate terminal GTM and a drain terminal DTM described later.

The orientation films ORI1 and ORI2, the transparent pixel electrode ITO1 and the common transparent pixel electrode ITO2, and their respective layers are formed inside the seal pattern SL. Polarizing plate P
OL1 and POL2 are lower transparent glass substrates SUB, respectively.
1. Formed on the outer surface of the upper transparent glass substrate SUB2. The liquid crystal LC is enclosed in a region partitioned by a seal pattern SL between a lower alignment film ORI1 and an upper alignment film ORI2 that set the orientation of liquid crystal molecules. The lower alignment film ORI1 is a protective film P on the lower transparent glass substrate SUB1 side.
It is formed on top of SV1.

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 applied to the substrate SUB2.
Formed on the side, the lower transparent glass substrate SUB1 and the upper transparent glass substrate SUB2 are overlapped, the liquid crystal LC is injected from the opening INJ of the sealing material SL, and the injection port INJ is sealed with epoxy resin or the like to form the upper and lower substrates. It is assembled by cutting.

<< Thin Film Transistor TFT >> Next, referring to FIG.
Returning to FIG. 3, the configuration on the TFT substrate SUB1 side will be described in detail.

The thin film transistor TFT has a gate electrode G
When a positive bias is applied to T, the channel resistance between the source and the drain decreases, and when the bias is zero, the channel resistance increases.

A plurality of (two) thin film transistors TFT1 and TFT2 are redundantly provided in each pixel. Each of the thin film transistors TFT1 and TFT2 has substantially the same size (channel length and channel width are the same), and has a gate electrode GT, a gate insulating film GI, and an i-type (intrinsic,
intrinsic, conductivity type determination impurities are not doped)
It has an i-type semiconductor layer AS made of amorphous silicon (Si), a pair of source electrodes SD1 and a drain electrode SD2. It should be understood that the source and drain are originally determined by the bias polarity between them, and the polarity is inverted during operation in the circuit of this liquid crystal display device, so it should be understood that the source and drain are switched during operation. However, in the following description, for convenience, one is fixed as the source and the other is fixed as the drain.

<< Gate Electrode GT >> The gate electrode GT is formed in a shape protruding in the vertical direction from the scanning signal line GL (branched into a T shape). The gate electrode GT projects so as to extend beyond the respective active regions of the thin film transistors TFT1 and TFT2. Thin film transistor TFT
The gate electrodes GT of the TFT 1 and the TFT 2 are integrally formed (as a common gate electrode) and are formed continuously with the scanning signal line GL. In this example, the gate electrode GT is formed of the single-layer second conductive film g2. An aluminum (Al) film formed by sputtering, for example, is used as the second conductive film g2, and an Al anodic oxide film AOF is provided thereon.

The gate electrode GT is formed larger than it so as to completely cover the i-type semiconductor layer AS (as viewed from below), and is devised so that the i-type semiconductor layer AS is not exposed to outside light or backlight light. .

<< Scanning Signal Line GL >> The scanning signal line GL is the second
It is composed of a conductive film g2. The second conductive film g2 of the scanning signal line GL is formed in the same manufacturing process as the second conductive film g2 of the gate electrode GT, and is integrally formed. Also, an Al anodic oxide film AOF is provided on the scanning signal line GL.

<< Insulating Film GI >> The insulating film GI is used as a gate insulating film for applying an electric field to the semiconductor layer AS in the thin film transistors TFT1 and TFT2 together with the gate electrode GT. The insulating film GI is formed on the gate electrode GT and the scanning signal line GL. As the insulating film GI, for example, a silicon nitride film formed by plasma CVD is selected and is formed to a thickness of 1200 to 2700Å (in this embodiment, about 2000Å). As shown in FIG. 6, the gate insulating film GI is formed so as to surround the entire matrix portion AR, and the peripheral portion is removed so as to expose the external connection terminals DTM and GTM. The insulating film GI is a scanning signal line G
It also contributes to the electrical insulation between L and the video signal line DL.

<< i-type semiconductor layer AS >> i-type semiconductor layer AS
In this example, each of the thin film transistors TFT1 and TFT2 is formed as an independent island, and is made of amorphous silicon and has a thickness of 200 to 2200Å (2 in this example.
The film thickness is about 000Å). The layer d0 is a phosphorus (P) -doped N (+)-type amorphous silicon semiconductor layer for ohmic contact, the i-type semiconductor layer AS exists on the lower side, and the conductive layer d2 (d3) exists on the upper side. It is left only where you do.

The i-type semiconductor layer AS is also provided between both the intersections (crossover portions) of the scanning signal lines GL and the video signal lines DL. The i-type semiconductor layer AS at the intersection reduces the short circuit between the scanning signal line GL and the video signal line DL at the intersection.

<< Transparent Pixel Electrode ITO1 >> Transparent Pixel Electrode I
TO1 constitutes one of the pixel electrodes of the liquid crystal display section.

The transparent pixel electrode ITO1 is the source electrode SD1 of the thin film transistor TFT1 and the thin film transistor T.
It is connected to both source electrodes SD1 of FT2. Therefore, even if a defect occurs in one of the thin film transistors TFT1 and TFT2, if the defect causes a side effect, an appropriate portion is cut by laser light or the like, and if not, the other thin film transistor operates normally. You can leave it alone because it does. The transparent pixel electrode ITO1 is composed of the first conductive film d1.
Is a transparent conductive film (Indium-Tin) formed by sputtering.
-Oxide ITO: Nesa film), 1000-200
With a thickness of 0Å (in this embodiment, a film thickness of about 1400Å)
It is formed.

<< Source Electrode SD1, Drain Electrode SD
2 >> Each of the source electrode SD1 and the drain electrode SD2 is composed of a second conductive film d2 in contact with the N (+) type semiconductor layer d0 and a third conductive film d3 formed thereon.

The second conductive film d2 is a chromium (Cr) film formed by sputtering and is formed to a thickness of 500 to 1000 Å (in this embodiment, about 600 Å). If the Cr film is formed thicker, the stress increases.
It is formed within a range not exceeding the film thickness of 0Å. Cr film is N
It is used for the purpose of improving adhesion to the (+) type semiconductor layer d0 and preventing Al of the third conductive film d3 from diffusing into the N (+) type semiconductor layer d0 (so-called barrier layer). Second
As the conductive film d2, in addition to the Cr film, refractory metal (Mo, T
i, Ta, W) film, refractory metal silicide (MoS
An i ₂ , TiSi ₂ , TaSi ₂ , WSi ₂ ) film may be used.

The third conductive film d3 is formed by sputtering Al to a thickness of 3000 to 5000 Å (400 in this embodiment).
0 Å) formed. The Al film has less stress than the Cr film and can be formed to have a large film thickness, and the source electrode SD1, the drain electrode SD2 and the video signal line DL can be formed.
Of the gate electrode GT and the i-type semiconductor layer AS are ensured (step coverage is improved).

After patterning the second conductive film d2 and the third conductive film d3 with the same mask pattern, an N (+) type film is formed by using the same mask or by using the second conductive film d2 and the third conductive film d3 as a mask. The semiconductor layer d0 is removed. That is,
The N (+) type semiconductor layer d0 remaining on the i type semiconductor layer AS
The portions other than the second conductive film d2 and the third conductive film d3 are removed by self-alignment. At this time, the N (+) type semiconductor layer d
Since 0 is etched so that the entire thickness thereof is removed, the surface portion of the i-type semiconductor layer AS is also slightly etched, but the degree may be controlled by the etching time.

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

<< Protective Film PSV1 >> Thin Film Transistor TF
A protective film PSV1 is provided on the T and the transparent pixel electrode ITO1. The protective film PSV1 is formed mainly for protecting the thin film transistor TFT from moisture and the like,
Use one with 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 1 μm.
It is formed with a film thickness of about m.

As shown in FIG. 6, the protective film PSV1 is formed so as to surround the entire matrix portion AR, the peripheral portion is removed so as to expose the external connection terminals DTM and GTM, and the common electrode of the upper substrate side SUB2 is formed. COM to the lower substrate SUB
Silver paste A on the lead wire INT for connecting the external connection terminal 1
The part connected by GP is also removed. Protective film PSV1
Regarding the thickness relationship between the gate insulating film GI and the gate insulating film GI, the former is made thicker in consideration of the protection effect, and the latter is made thin in the transconductance gm of the transistor. Therefore, as shown in FIG.
The protective film PSV1 having a high protective effect is formed so as to be larger than the gate insulating film GI so as to protect the peripheral portion over as wide a range as possible.

<< Light-shielding film BM >> Upper transparent glass substrate SUB
On the second side, external light or backlight is exposed to the i-type semiconductor layer A.
A light shielding film BM is provided so as not to enter S. Figure 2
The closed polygonal contour line of the light-shielding film BM shown in (3) indicates an opening inside which the light-shielding film BM is not formed. The light shielding film BM is formed of an organic resin film added with a black pigment. In this embodiment, a negative photosensitive resin film CK-2000 manufactured by Fuji Hunt Technology Co., Ltd. is formed to a thickness of about 1.5 μm. A space between the light shielding films BM is filled with a transparent resin film FU to be flattened, and a color filter FIL is formed thereon. In this embodiment, the transparent resin film FU is formed of a negative type transparent photosensitive resin film CT manufactured by Fuji Hunt Technology Co., Ltd. The light shielding film BM may be formed of, for example, an aluminum film or a chromium film having a high light shielding property, and for example, the chromium film is formed by sputtering to have a thickness of about 1300Å.

Therefore, the thin film transistors TFT1 and TF
The i-type semiconductor layer AS of T2 is sandwiched by the upper and lower light-shielding films BM and the large gate electrode GT,
External natural light or backlight does not hit. The light-shielding film BM is formed in a lattice shape around each pixel (so-called black matrix), and the effective display area of one pixel is partitioned by this lattice. Therefore, the outline of each pixel is the light-shielding film BM.
Improves clarity and contrast. That is, the light blocking film BM has two functions of blocking the i-type semiconductor layer AS and serving as a black matrix.

Since the edge portion of the transparent pixel electrode ITO1 on the base side in the rubbing direction (the lower right portion in FIG. 2) is also shielded by the light shielding film BM, even if a domain occurs in the above portion, the domain cannot be seen. The display characteristics do not deteriorate.

The light-shielding film BM is also formed in a frame shape in the peripheral portion, and its pattern has a plurality of dots-like openings.
It is formed continuously with the pattern of the matrix portion shown in FIG. As shown in FIGS. 7 and 8, the light shielding film BM in the peripheral portion is extended to the outside of the seal portion SL to prevent leakage light such as reflected light caused by a mounting machine such as a personal computer from entering the matrix portion. . On the other hand, the light-shielding film BM is kept inside by about 0.3 to 1.0 mm from the edge of the substrate SUB2.
It is formed so as to avoid the cutting region of UB2.

<< Color Filter FIL >> The color filter FIL is formed in a stripe shape by repeating red, green and blue at positions facing the pixels. The color filter FIL is formed to have a large size so as to cover all of the transparent pixel electrode ITO1, and the light shielding film BM overlaps with the edge portions of the color filter FIL and the transparent pixel electrode ITO1.
It is formed inside the peripheral portion of TO1.

The color filter FIL can be formed as follows. First, a dyeing base material such as an acrylic resin is formed on the surface of the upper transparent glass substrate SUB2, and the dyeing base material other than the red filter forming region is removed by a photolithography technique. After that, the dyed substrate is dyed with a red dye and a fixing process is performed to form a red filter R. Next, the green filter G and the blue filter B are sequentially formed by performing the same process.

<< Protective Film PSV2 >> The protective film PSV2 is provided to prevent the dye of the color filter FIL from leaking to the liquid crystal LC. The protective film PSV2 is formed of a transparent resin material such as acrylic resin or epoxy resin.

<< Common Transparent Pixel Electrode ITO2 >> The common transparent pixel electrode ITO2 opposes the transparent pixel electrode ITO1 provided for each pixel on the lower transparent glass substrate SUB1 side, and the optical state of the liquid crystal LC is the pixel electrode ITO1. And the common transparent pixel electrode ITO2 change in response to a potential difference (electric field). A common voltage Vcom is applied to the common transparent pixel electrode ITO2. In this embodiment, the common voltage Vcom is the minimum level drive voltage Vdmin and the maximum level drive voltage V applied to the video signal line DL.
Although it is set to an intermediate DC potential with respect to dmax, an AC voltage may be applied if it is desired to reduce the power supply voltage of the integrated circuit used in the video signal drive circuit to about half. For the planar shape of the common transparent pixel electrode ITO2, see FIG.

<< Structure of Storage Capacitance Element Cadd >> The transparent pixel electrode ITO1 is formed so as to overlap the adjacent scanning signal line GL at the end opposite to the end connected to the thin film transistor TFT. In this superposition, as is clear from FIG. 4, the transparent pixel electrode ITO1 is used as one electrode PL2 and the adjacent scanning signal line GL is used as the other electrode PL.
A holding capacitance element (electrostatic capacitance element) Cadd which is 1 is configured. The dielectric film of the storage capacitor Cadd is an insulating film G used as a gate insulating film of the thin film transistor TFT.
I and the anodic oxide film AOF.

The storage capacitor element Cadd is formed in a portion where the width of the second conductive film g2 of the scanning signal line GL is widened. The second conductive film g2 at the portion intersecting the video signal line DL is thinned in order to reduce the probability of short circuit with the video signal line DL.

Even if the transparent pixel electrode ITO1 is broken in the step portion of the electrode PL1 of the storage capacitor Cadd, the second conductive film d2 and the third conductive film d2 formed so as to cross the step.
The defect is compensated by the island region formed of the conductive film d3.

<< Gate Terminal Section >> FIG. 9 is a diagram showing a connection structure from the scanning signal line GL of the display matrix to its external connection terminal GTM. (A) is a plane and (B) is B of (A). -B shows a cross section taken along the line B. The drawing corresponds to the lower part of FIG. 6, and the diagonal wiring portions are shown as straight lines for convenience.

AO is a mask pattern for photographic processing, in other words, a photoresist pattern for selective anodic oxidation. Therefore, this photoresist is removed after anodization,
The pattern AO shown in the figure does not remain as a finished product, but since the oxide film AOF is selectively formed on the gate line GL as shown in the cross-sectional view, its locus remains. In the plan view, with respect to the photoresist boundary line AO, the left side is a region covered with the resist and not anodized, and the right side is a region exposed from the resist and anodized. Anodized A
The oxide Al ₂ O ₃ film AOF is formed on the surface of the L layer g2, and the volume of the conductive portion therebelow is reduced. Of course, the anodic oxidation is performed by setting an appropriate time and voltage so that the conductive portion remains. The mask pattern AO does not intersect with the scanning line GL by a single straight line, but is bent in a crank shape and intersects.

In the figure, the AL layer g2 is hatched for easy understanding, but the region which is not anodized is patterned in a comb shape. This is because whiskers are generated on the surface when the width of the Al layer is wide. Therefore, by narrowing the width of each one and arranging a plurality of them in parallel, whiskers can be prevented and wire breakage can be prevented. The aim is to minimize the probability of and the sacrifice of conductivity. Therefore, in this example, the portion corresponding to the base of the comb is also displaced along the mask AO.

The gate terminal GTM has a Cr layer g1 which has good adhesion to the silicon oxide SIO layer and which has a higher electrical contact resistance than Al or the like.
Further, the surface thereof is protected and is composed of a transparent conductive layer d1 of the same level (same layer, simultaneously formed) as the pixel electrode ITO1.
In addition, the conductive layers d2 and d3 formed on the gate insulating film GI and on the side surfaces thereof have their regions so that the conductive layers g2 and g1 are not etched together due to pinholes or the like during the etching of the conductive layers d3 and d2. It remains as a result of being covered with photoresist. In addition, the ITO layer d1 which extends over the gate insulating film GI and extends rightward is one in which the same measures are taken more thoroughly.

In the plan view, the gate insulating film GI is formed on the right side of the boundary line and the protective film PSV1 is formed on the right side of the boundary line, and the terminal portion GTM located at the left end is formed.
Are exposed from them to allow electrical contact with external circuitry. Although only one pair of the gate line GL and the gate terminal is shown in the figure, in actuality, a plurality of such pairs are vertically arranged as shown in FIG. 6 to form the terminal group Tg (FIG. 6). The left end of the gate terminal is
It extends beyond the cutting region CT1 of the substrate and is short-circuited by the wiring SHg. Such a short-circuit line S in the manufacturing process
Hg is useful for supplying power during anodization and preventing electrostatic breakdown during rubbing of the alignment film ORI1.

<< Drain Terminal DTM >> FIG. 10 is a diagram showing the connection from the video signal line DL to the external connection terminal DTM, (A) shows the plane, and (B) shows B of (A).
-B shows a cross section taken along the line B. The drawing corresponds to the vicinity of the upper right of FIG. 6, and although the orientation of the drawing is changed for convenience, the right end direction corresponds to the upper end portion (or the lower end portion) of the substrate SUB1.

TSTd is an inspection terminal, which is not connected to an external circuit, but is wider than the wiring portion so that a probe needle or the like can come into contact therewith. Similarly, the drain terminal D
The width of the TM is also wider than that of the wiring portion so that the TM can be connected to an external circuit. The inspection terminals TSTd and the external connection drain terminals DTM are alternately arranged in a zigzag pattern in the vertical direction, and the inspection terminals TSTd terminate without reaching the end portion of the substrate SUB1 as shown in the figure, but the drain terminal DTM.
6 further extend beyond the cutting line CT1 of the substrate SUB1 to form a terminal group Td (subscripts omitted) as shown in FIG. 6, all of which are interconnected to each other to prevent electrostatic breakdown during the manufacturing process.
Shorted by Hd. The drain connection terminal is connected to the opposite side of the matrix of the video signal lines DL in which the inspection terminals TSTd are present, and conversely the inspection terminal is placed on the opposite side of the matrix of the video signal lines DL in which the drain connection terminals DTM are present. Are connected.

The drain connection terminal DTM has the Cr layer g1 and the ITO layer d1 for the same reason as the above-mentioned gate terminal GTM.
Is formed of two layers, and is connected to the video signal line DL at a portion where the gate insulating film GI is removed. The semiconductor layer AS formed on the end portion of the gate insulating film GI is for etching the edge of the gate insulating film GI in a tapered shape. The protective film PSV1 is, of course, removed on the terminal DTM to connect to an external circuit. AO is the anodizing mask described above, and its boundary line is formed so as to largely surround the entire matrix. In the figure, the left side of the boundary line is covered with the mask, but the layer g2 is covered in the part not covered in this figure. This pattern is not directly relevant as it does not exist.

The lead wiring from the matrix portion to the drain terminal portion DTM is, as shown in FIG. 7C, a video signal line DL immediately above the layers d1 and g1 at the same level as the drain terminal portion DTM. Although the layers d2 and d3 of the same level are laminated part way up to the middle of the seal pattern SL, this minimizes the probability of disconnection and facilitates electrical contact.
The purpose is to protect the l layer d3 as much as possible with the protective film PSV1 and the seal pattern SL.

<< Equivalent Circuit of Entire Display Device >> FIG. 11 shows a wiring diagram of the equivalent circuit of the display matrix portion and its peripheral circuits.
Although the figure is a circuit diagram, it is drawn corresponding to the actual geometrical arrangement. AR is a matrix array in which a plurality of pixels are two-dimensionally arranged.

In the figure, X means a video signal line DL, and subscripts G, B and R are added corresponding to green, blue and red pixels, respectively. Y represents the scanning signal line GL, and subscripts 1, 2, 3, ..., End are added according to the order of scanning timing.

The video signal lines X (subscripts omitted) are alternately connected to the upper (or odd) video signal drive circuit He and the lower (or even) video signal drive circuit Ho.

The scanning signal line Y (subscript omitted) is connected to the vertical scanning circuit V.

The SUP is a TFT liquid crystal display device for displaying information for a CRT (cathode ray tube) from a power supply circuit for obtaining a plurality of divided and stabilized voltage sources from one voltage source and a host (upper processing unit). It is a circuit including a circuit for exchanging information for use.

<< Function of Storage Capacitance Element Cadd >> The storage capacity element Cadd functions to reduce the influence of the gate potential change ΔVg on the midpoint potential (pixel electrode potential) Vlc when the thin film transistor TFT switches. This situation is expressed by the following equation.

ΔVlc = {Cgs / (Cgs + Cadd + Cpix)} × ΔVg where Cgs is the gate electrode G of the thin film transistor TFT
Parasitic capacitance formed between T and source electrode SD1, C
pix is a capacitance formed between the transparent pixel electrode ITO1 (PIX) and the common transparent pixel electrode ITO2 (COM), ΔV
lc represents a change amount of the pixel electrode potential due to ΔVg. This variation ΔVlc causes a direct current component applied to the liquid crystal LC, but the value can be reduced as the holding capacitance Cadd is increased. Further, the storage capacitor element Cadd also has the function of prolonging the discharge time, and thus the thin film transistor TFT
Accumulates video information for a long time after is turned off. The reduction of the direct current component applied to the liquid crystal LC improves the life of the liquid crystal LC,
It is possible to reduce so-called burn-in in which the previous image remains when the liquid crystal display screen is switched.

As described above, since the gate electrode GT is made large enough to completely cover the i-type semiconductor layer AS, the overlap area with the source electrode SD1 and the drain electrode SD2 is increased, and the parasitic capacitance Cgs is increased accordingly. The reverse effect is that the midpoint potential Vlc is easily affected by the gate (scanning) signal Vg. However, this demerit can be eliminated by providing the storage capacitor element Cadd.

The holding capacitance of the holding capacitance element Cadd is 4 to 8 times (4.C
pix <Cadd <8 · Cpix), 8 to 3 for parasitic capacitance Cgs
Set to a value about twice (8 · Cgs <Cadd <32 · Cgs).

The first-stage scanning signal line GL (Y ₀ ) used only as the storage capacitor electrode line is the common transparent pixel electrode ITO2.
Set to the same potential as (Vcom). In the example of FIG. 6, the scanning signal line at the first stage is short-circuited to the common electrode COM through the terminal GT0, the lead wire INT, the terminal DT0 and the external wiring. Alternatively, the storage capacitor electrode line Y ₀ in the first stage is the scanning signal line Ye in the last stage.
It may be connected to nd, connected to a DC potential point (AC ground point) other than Vcom, or connected to receive one extra scanning pulse Y ₀ from the vertical scanning circuit V.

<< Overall Configuration of Liquid Crystal Display Module >> FIG.
[Fig. 3] is an exploded perspective view showing each component of the liquid crystal display module MDL.

SHD is a frame-shaped shield case (metal frame) made of a metal plate, LCW is its display window, PNL.
Is a liquid crystal display panel, SPB is a light diffusion plate, MFR is an intermediate frame, BL is a cold cathode fluorescent lamp as a light source of a backlight, BLS is a backlight support, and LCA is a lower case. In this arrangement, the respective members are stacked to assemble the module MDL.

The module MDL is a shield case SH.
The whole is fixed by the claw CL and the hook FK provided on D.

The intermediate frame MFR is formed in a frame shape so as to have an opening corresponding to the display window LCW, and the frame portion has a diffusion plate SPB, a backlight support BLS, and various circuit components in accordance with their shapes and thicknesses. There are irregularities and openings for heat dissipation.

The lower case LCA also serves as a reflector of backlight light, and a reflection mountain RM is formed corresponding to the fluorescent tube BL so as to reflect light efficiently.

<< Display Panel PNL and Drive Circuit Board PCB
1 >> FIG. 13 is a top view showing a state in which the video signal drive circuits He and Ho and the vertical scanning circuit V are connected to the display panel PNL shown in FIG.

CHI is a driving IC chip for driving the display panel PNL (the lower three are driving ICs on the vertical scanning circuit side).
Chips, 6 each on the left and right are drive I on the video signal drive circuit side
C chip). TCP is a tape carrier package in which a driving IC chip CHI is mounted by a tape automated bonding method (TAB) as will be described later with reference to FIGS. 14 and 15, and PCB1 is a driving in which the TCP, the capacitor CDS and the like are mounted. It is divided into three parts on the circuit board. FGP is a frame ground pad,
A spring-like fragment FG provided by cutting into the shield case SHD is soldered. FC is a flat cable that electrically connects the lower drive circuit board PCB1 and the left drive circuit board PCB1, and the lower drive circuit board PCB1 and the right drive circuit board PCB1. As the flat cable FC, as shown in the figure, a plurality of lead wires (phosphor bronze material plated with Sn) sandwiched between a striped polyethylene layer and a polyvinyl alcohol layer are used.

<< TCP Connection Structure >> FIG. 14 shows a sectional structure of a tape carrier package TCP in which an integrated circuit chip CHI, which constitutes the scanning signal driving circuit V and the video signal driving circuits He and Ho, is mounted on a flexible wiring board. FIG. 15 is a cross-sectional view of essential parts showing a state in which it is connected to the liquid crystal display panel, in this example, the video signal circuit terminal DTM.

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 and has inner end portions (commonly called inner leads). ) Is the integrated circuit C
The HI bonding pad PAD is connected by a so-called face-down bonding method. Terminals TTB, T
Outer end portions (commonly called outer leads) of TM correspond to the input and output of the semiconductor integrated circuit chip CHI,
CRT / TFT conversion circuit / power supply circuit S by soldering, etc.
A liquid crystal display panel P is formed on the UP by an anisotropic conductive film ACF.
Connected to NL. The package TCP has a protective film PS whose front end exposes the connection terminal DTM on the panel PNL side.
Since it is connected to the panel so as to cover V1, and therefore the external connection terminal DTM (GTM) is covered by at least one of the protective film PSV1 and the package TCP, it is strong against electric contact.

BF1 is a base film made of polyimide or the like, and SRS is a solder resist film for masking the solder so that it will not stick to an unnecessary place 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 a silicone resin SIL is further filled between the package TCP and the upper substrate SUB2 for multiple protection.

<< Drive Circuit Board PCB2 >> Intermediate Frame M
As shown in FIG. 16, the drive circuit board PCB2 of the liquid crystal display LCD held and housed in the FR is L-shaped, and has electronic parts such as ICs, capacitors and resistors mounted thereon. This drive circuit board PCB2 is provided with a power supply circuit for obtaining a plurality of divided and stabilized voltage sources from one voltage source, and information for a CRT (cathode ray tube) from a host (upper processing unit). A circuit SUP including a circuit for converting into information for a TFT liquid crystal display device is mounted. CJ is a connector connecting portion to which a connector (not shown) connected to the outside is connected. The drive circuit board PCB2 and the inverter circuit board PCB3 are electrically connected by a backlight cable through a connector hole provided in the intermediate frame MFR.

Drive circuit board PCB1 and drive circuit board PC
B2 is electrically connected by a foldable flat cable FC. When assembled, drive circuit board PCB
2 is stacked on the back side of the drive circuit board PCB1 by bending the flat cable FC by 180 ° and fitted into a predetermined recess of the intermediate frame MFR.

Although the present invention has been specifically described based on the above embodiments, the present invention is not limited to the above embodiments and can be variously modified without departing from the scope of the invention. Is. For example, although the organic resin film is used as the black matrix BM in the above embodiments, an aluminum film, a chromium film or the like having a high light shielding property may be formed by the sputtering method or the vapor deposition method. Further, the present invention is applicable not only to the active matrix type liquid crystal display device but also to a simple matrix type liquid crystal display device.

[0093]

As described above, according to the present invention, the space between the selectively provided light-shielding film or the black matrix is filled with the transparent resin film with substantially the same thickness, and the light-shielding film or the black matrix and the transparent resin film are formed. Is almost flattened,
Variations in the thickness of the liquid crystal layer are reduced, variations in the threshold voltage of the liquid crystal and domains are reduced, and display quality can be improved.

[Brief description of drawings]

FIG. 1A to FIG. 1D are process cross-sectional views showing a method of manufacturing a transparent glass substrate having a black matrix and a color filter according to an embodiment of the liquid crystal display device of the present invention.

FIG. 2 is a main-portion plan view showing one pixel and its periphery of a liquid crystal display portion of an active matrix type color liquid crystal display device to which the present invention is applied.

FIG. 3 is a cross-sectional view showing one pixel and its periphery taken along the section line 3-3 in FIG.

FIG. 4 is a cross-sectional view of the additional capacitance Cadd taken along the line 4-4 in FIG.

FIG. 5 is a plan view for explaining the configuration of the matrix peripheral portion of the display panel.

FIG. 6 is an enlarged plan view of a corner portion of a display panel including electrical connection portions of upper and lower substrates.

FIG. 7 is a cross-sectional view showing the vicinity of a panel angle and the vicinity of a video signal terminal portion on both sides, with the pixel portion of the matrix at the center.

FIG. 8 is a cross-sectional view showing a scan signal terminal on the left side and a panel edge portion without an external connection terminal on the right side.

FIG. 9 is a plan view and a cross-sectional view showing the vicinity of a connecting portion between a gate terminal GTM and a gate wiring GL.

FIG. 10 is a plan view and a cross-sectional view showing the vicinity of a connecting portion between a drain terminal DTM and a video signal line DL.

FIG. 11 is a circuit diagram including a matrix portion of an active matrix type color liquid crystal display device and its periphery.

FIG. 12 is an exploded perspective view of a liquid crystal display module.

FIG. 13 is a top view showing a state in which a peripheral drive circuit is mounted on a liquid crystal display panel.

FIG. 14 is a diagram showing a cross-sectional structure of a tape carrier package TCP in which an integrated circuit chip CHI forming a drive circuit is mounted on a flexible wiring board.

FIG. 15 is a main-portion cross-sectional view showing a state where the tape carrier package TCP is connected to the video signal circuit terminal DTM of the liquid crystal display panel PNL.

FIG. 16: Peripheral drive circuit board PCB1 (top surface visible)
It is a top view which shows the connection state of power supply circuit circuit board PCB2 (a lower surface is visible).

FIG. 17 is a cross-sectional view of a main part of a transparent glass substrate provided with a conventional black matrix and color filters.

[Explanation of symbols]

SUB2 ... Transparent glass substrate, BM ... Black matrix, FU ... Transparent resin film, FIL (R) ... Red color filter, FIL (G) ... Green color filter, FIL
(B) ... Blue color filter.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Akiko Kubo 3300 Hayano, Mobara-shi, Chiba Hitachi, Ltd. Electronic Device Division (72) Inventor Tatsuo Hamamoto 3300 Hayano, Mobara-shi, Chiba Hitachi, Ltd. Electronic Device Business (72) Inventor Shoya Izumi 3300 Hayano, Mobara-shi, Chiba Hitachi, Ltd. Electronic Device Division

Claims (3)

[Claims] 1. A liquid crystal display device in which a light-shielding film is selectively provided on the surface of a transparent substrate which constitutes a liquid crystal display panel, and a transparent resin film is provided between the light-shielding films so as to have a film thickness substantially equal to that of the light-shielding film. Liquid crystal display device characterized by being embedded. 2. Two transparent glass substrates are stacked with a predetermined gap therebetween so that the surfaces provided with the transparent pixel electrodes and the alignment film face each other, and are provided in a frame shape around the edge between the two substrates. Affixing both substrates with a sealing material,
A liquid crystal display panel is provided in which a liquid crystal is sealed inside the sealing material, and a polarizing plate is provided outside the both substrates, and an organic or inorganic light-absorbing substance is provided on one surface of the transparent glass substrate. In a liquid crystal display device in which a black matrix composed of a transparent resin film and an organic resin is selectively provided, the black matrix and the transparent resin film are filled with a transparent resin film between the black matrices with a film thickness substantially equal to the black matrix. And a color filter provided between the black matrix and the black matrix, and the transparent pixel electrode and the alignment film provided on the color filter. 3. Two transparent glass substrates are stacked with a predetermined gap therebetween so that the surfaces provided with the transparent pixel electrodes and the alignment film face each other, and are provided in a frame shape around the edge between the two substrates. Affixing both substrates with a sealing material,
A liquid crystal display panel is provided in which a liquid crystal is sealed inside the sealing material, and a polarizing plate is provided outside the both substrates, and an organic or inorganic light-absorbing substance is provided on one surface of the transparent glass substrate. In a liquid crystal display device selectively provided with a black matrix having a film thickness of about 0.5 to 4 μm and made of an organic resin, a transparent resin film is embedded between the black matrices to have a film thickness substantially equal to that of the black matrix. , The black matrix and the transparent resin film are substantially flattened, a color filter is provided between them on the black matrix, and a protective film of the color filter, the transparent pixel electrode, and the alignment film are provided thereon. A liquid crystal display device characterized by being provided in sequence.