JPH0815716A - Liquid crystal display device - Google Patents

Abstract

PURPOSE:To obtain a liquid crystal display device which permits reduction of the outside dimensions of a circuit board in spite of an increase in the number of data lines of display data with an increase in the number of display colors and is consequently capable of realizing a reduction in size by consisting of this circuit board of glass or plastic and forming the wirings of the circuit board by patterning by a photoetching technique. CONSTITUTION:This liquid crystal display element PNL is formed by superposing two sheets of transparent glass substrates in such a manner that the surfaces respectively provided with transparent pixel electrodes and oriented films face each other at a specified interval and sealing liquid crystals therebetween. The wirings of the circuit board CB which consists of the glass and patterned with the wirings by the photoetching technique are anisotropically conductive films ACF connected by a tape carrier package TCP packaged with an integrated circuit chip. The circuit board CB is composed of the glass and the wirings of the circuit board CB are formed by patterning by the photoetching technique, by which the wirings and the pitches are made finer and the wiring density is increased.

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 including a liquid crystal display element and a circuit board for driving the same.

[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,
A liquid crystal display in which both substrates are bonded together, liquid crystal is sealed inside the sealing material between both substrates through a liquid crystal sealing port provided in a part of the sealing material, and a polarizing plate is provided outside both substrates. An element (that is, a liquid crystal display panel or a liquid crystal display unit), a backlight arranged below the liquid crystal display element for supplying light to the liquid crystal display element, and a driving unit arranged outside the outer peripheral portion of the liquid crystal display element. It includes a circuit board, a frame-shaped body that is a molded product that holds each of these members, and a metal frame that houses each of these members and has a liquid crystal display window opened.

The liquid crystal display element and the circuit board are electrically connected by a tape carrier package (TCP) having an integrated circuit chip (driver) for driving the liquid crystal mounted thereon.

The active matrix type liquid crystal display device is provided with a non-linear element (switching element) corresponding to each of a plurality of pixel electrodes arranged in a matrix. Since the liquid crystal in each pixel is theoretically always driven (duty ratio 1.0), the contrast of the active matrix method is better than that of the so-called simple matrix method, which employs the time division driving method.
In particular, it is becoming an indispensable technology for color liquid crystal display devices. A typical example of the switching element is a thin film transistor (TFT).

An active matrix type liquid crystal display device using thin film transistors is disclosed in, for example, Japanese Unexamined Patent Publication No. 63-309921, "1.
2.5-inch active matrix color LCD ", Nikkei Electronics, pages 193-210, 1986 12
Known on the 15th of March, published by Nikkei McGraw-Hill, Inc.

In a conventional active matrix type liquid crystal display device, thin film transistors, scanning signal lines and video signal lines are formed, and the scanning signal lines and video signal lines are driven around a liquid crystal display element in which liquid crystal is sealed. A circuit board is provided on which peripheral circuit wirings for generating liquid crystal display data and liquid crystal display timing signals required by the integrated circuit chip and transmitting them to each integrated circuit chip are formed. The liquid crystal display element and the circuit board are electrically connected by a tape carrier package in which an integrated circuit chip is mounted on a tape carrier. That is, the output terminal of the drive wiring of the circuit board and the input terminal of the tape carrier package are connected by soldering, and the output terminal of the tape carrier package and the input terminal of the scanning signal line or the video signal line of the liquid crystal display element are connected. It is electrically connected through the anisotropic conductive film. The tape carrier package is placed mainly on the circuit board between the liquid crystal display element and the circuit board.

FIG. 9 is a sectional view showing a connection between a conventional liquid crystal display element, a printed circuit board and a tape carrier package.

The PNL is a liquid crystal display element (that is, a liquid crystal display panel or a liquid crystal display unit), the PCB is a printed circuit board on which wiring is formed by printing, and the TCP is a tape carrier package on which an integrated circuit chip is mounted. , SLD is a solder connection portion for connecting an output terminal (not shown) of the signal wiring of the printed circuit board PCB and an input terminal of the tape carrier package TCP, AC
F is an anisotropic conductive film that connects the output terminal of the tape carrier package TCP and the input terminal of the liquid crystal display element PNL.

[0009]

When the number of display colors of the liquid crystal display device increases and the number of data lines of display data (the number of video signal lines) increases, in the conventional liquid crystal display device, the peripheral circuit wiring is printed on the printed circuit board. Since it is formed by the method, there is a problem that the miniaturization of the wiring pitch is restricted, and even when a multilayer substrate is used, the outer dimension of the printed board becomes large, especially the width, and the outermost dimension of the liquid crystal display device becomes large.

At present, the market of notebook-sized personal computers and word processors in which a liquid crystal display device is mounted as a display unit is rapidly expanding, and there is a strong demand for reducing the width of a so-called frame portion around the display screen as much as possible. ing. Since the width of the frame portion is mainly determined by the width of the circuit board arranged on the outer peripheral portion of the liquid crystal display element, the width of the circuit board must be reduced in order to reduce the width of the frame portion. However, with the recent trend of increasing the number of display colors of liquid crystal display devices, multi-gradation display, high definition, and large screen, electric signal lines and power supplies supplied to the tape carrier package through the circuit board. The number of wirings such as lines is increasing, and the width of the frame portion is increasing. In order to reduce the width of the circuit board as much as possible and increase the number of connections, the wiring and pitch of the circuit board must be miniaturized to increase the connection density. Although the width of the tape carrier package has been reduced due to the progress of semiconductor technology, the width of the driving circuit board has not been reduced.

It is an object of the present invention to reduce the external dimensions of the circuit board even if the number of display colors increases and the number of display data lines increases, and as a result, downsizing can be realized. An object is to provide a liquid crystal display device.

[0012]

In order to achieve the above object, the present invention defines two insulating substrates made of glass or plastic so that the surfaces on which the transparent pixel electrodes and the alignment film are provided face each other. Are overlapped with each other with a gap therebetween, the both substrates are bonded together by a seal material provided in a frame shape around the edge between the both substrates, and liquid crystal is sealed between the both substrates inside the seal material. In a liquid crystal display device including a liquid crystal display element, a semiconductor integrated circuit chip for driving the liquid crystal display element, and a circuit board for driving the liquid crystal display element, the circuit board is made of glass or plastic, It is characterized in that the wiring (including terminals) of the circuit board is patterned by a photoetching technique (photolithography technique and etching technique).

Further, the liquid crystal display element and the circuit board are electrically connected by a tape carrier package on which the semiconductor integrated circuit chip is mounted.

Alternatively, the semiconductor integrated circuit chip is mounted on the surface of the insulating substrate of one of the both substrates, and the one of the insulating substrate and the circuit substrate is formed by a flexible printed circuit or a bonding wire. It is characterized by being electrically connected.

Further, one of the insulating substrates constituting the liquid crystal display element and the circuit substrate are made of the same material.

Further, one of the insulating substrates constituting the liquid crystal display element and the circuit substrate are formed of a single substrate made of the same material.

Further, the wiring of the circuit board is provided in multiple layers via an insulating film.

Further, one of the wirings is a solid layer which is connected to the ground or to which a predetermined voltage of a DC power source is applied.

A drive wiring is provided as a lower layer wiring (not limited to one layer) on the circuit board, and the solid layer is provided as an upper layer wiring on the circuit board via a first insulating film. A second insulating film is provided thereover.

Further, an opening is provided in the first insulating film and the second insulating film in a direction perpendicular to the circuit board surface, and a connection output terminal of the drive wiring is exposed in the opening. In addition, the solid layer has a pattern that avoids the opening.

The plurality of connection output terminals each extend in a first linear direction in a plane parallel to the circuit board surface, and are connected to the connection output terminals by the tape carrier package or the flexible. A plurality of connecting input terminals of the printed circuit extend in a second linear direction that traverses the first linear direction (eg, perpendicular to the first linear direction) in a plane parallel to the circuit board surface. And the opening exposing the connection output terminal is the first
Is arranged obliquely with respect to the linear direction or the second linear direction.

Further, the connection terminal portion and the tape carrier package or the flexible printed circuit are electrically connected via an anisotropic conductive film.

[0023]

In the present invention, the circuit board is made of glass or plastic, and the wiring of the circuit board is patterned and formed by the photoetching technique, whereby the wiring and the pitch can be miniaturized and the wiring density can be improved. it can.

By forming the insulating substrate constituting the liquid crystal display element and the circuit substrate from the same material of glass and plastic, the linear expansion coefficient of both can be made the same, and between them. Connected tape carrier package, flexible printed circuit,
Alternatively, it is possible to suppress the occurrence of stress on the bonding wire, so that the mechanical strength can be improved.

[0025]

Embodiments of the present invention will be described in detail below with reference to the drawings.

Example 1 FIG. 1 is a sectional view showing the connection between a liquid crystal display element, a circuit board and a tape carrier package showing Example 1 of the present invention.

The PNL is a liquid crystal display device in which 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 liquid crystal is sealed between them. (That is, a liquid crystal display panel or a liquid crystal display unit, which will be described in detail later), CB is made of glass,
A circuit board whose wiring is patterned by a known photoetching technique, TCP is a tape carrier package on which an integrated circuit chip is mounted, ACF is an output terminal (not shown) of the signal wiring of the circuit board CB, and an input terminal of the tape carrier package TCP (not shown). That is, the input side outer lead),
And an anisotropic conductive film that connects the output terminal of the tape carrier package TCP (that is, the outer lead on the output side) and the input terminal of the liquid crystal display element PNL.

In this embodiment, since the circuit board CB is made of glass and the wiring of the circuit board CB is formed by patterning by the photo-etching technique, the wiring and the pitch can be miniaturized and the wiring density can be increased. That is,
In the case of a conventional printed circuit board, the wiring width is 0.15m
m, the wiring pitch was about 0.3 mm, but in the case of the circuit board CB of this embodiment, the width of the wiring is 0.01 mm and the wiring pitch is about 0.02 mm. Therefore, the outer dimensions of the circuit board CB, especially the width of the circuit board CB can be reduced. As a result, the external dimensions of the liquid crystal display device, particularly the dimensions of the frame portion can be reduced, and a small-sized liquid crystal display device with a large screen can be provided.

Further, since the transparent glass substrates (SUB1 and SUB2 in FIG. 7) and the circuit board CB which compose the liquid crystal display element PNL are made of the same glass material, they have the same linear expansion coefficient. It is possible to prevent the tape carrier package TCP to be connected from being stressed by thermal shock or thermal cycle. Therefore, the mechanical strength can be improved and the connection reliability of the wiring can be improved.

Embodiment 2 FIG. 2 is a sectional view showing the connection between a liquid crystal display element and a circuit board showing Embodiment 2 of the present invention.

CHI is a semiconductor integrated circuit chip for driving the liquid crystal display element PNL, and FPC is a flexible printed circuit for electrically connecting the circuit board CB and the liquid crystal display element PNL.

In this embodiment, the bumps which are the connection terminals formed directly on the bottom surface of the integrated circuit chip CHI are connected to the terminal portions of the liquid crystal display element PNL via the anisotropic conductive film ACF to form the liquid crystal display element PNL. The circuit board CB is an anisotropic conductive film A using a flexible printed circuit FPC.
It is connected via CF. Also in this embodiment, the circuit board C
B is made of glass, and the wiring is patterned by the photo-etching technique.
The effect is obtained.

Example 3 FIG. 3 is a cross-sectional view showing the connection between a liquid crystal display element and a circuit board showing Example 3 of the present invention.

The present example is different from the structure of Example 2 in FIG. 2 in that a known bonding wire BW is used for connecting the liquid crystal display element PNL and the circuit board CB. In addition,
As the bonding wire BW, in order to prevent a short circuit of the signal line due to contact between the bonding wires BW, a covered wire covered with an insulating layer is used, or bonding is performed by sequentially changing the arc height or shape of the bonding wire BW. Go. Also in this embodiment, the same operation as in the first embodiment,
The effect is obtained.

Embodiment 4 FIG. 4A is a partial plan view of a circuit board showing Embodiment 4 of the present invention, and FIG. 4B is a sectional view taken along the line AA of FIG.

In this embodiment, first, a signal wiring SW made of a metal film is patterned as a first layer wiring (lower layer wiring) on a circuit board CB made of glass by a photoetching technique, and a silicon oxide film is formed thereon. A passivation film PAS1 made of an insulating film such as a (SiO ₂ film) or a silicon nitride film (Si ₃ N ₄ film) is formed.

Next, a solid layer AW made of a metal film is formed thereon as a second layer wiring (upper layer wiring). Solid layer A
W strengthens the ground line and removes the influence of noise that enters from the outside or that is generated inside the liquid crystal display device.
It is provided in order to obtain stable display quality and to suppress the generation of unnecessary radiated radio waves that cause EMI (electro magnetic interference). Solid layer AW
Is supplied with a ground potential of 0 V, a logic power supply voltage of 5 V, 3.3 V, or the like through a through hole (not shown). The metal layer forming the signal wiring SW and the solid layer AW includes aluminum (A
l), chromium (Cr), refractory metal (Mo, Ti, T
a, W) or refractory metal silicide (MoS
It is possible to use at least one layer of i ₂ , TiSi ₂ , TaSi ₂ , WSi ₂ ) film.

Next, a passivation film PAS2 is formed thereon as a second-layer insulating film with the same material as the passivation film PAS1.

Finally, on the passivation films PAS1 and PAS2 on the predetermined positions of the signal wiring SW, the tape carrier package TCP in the case of the embodiment 1 of FIG. 1 and the flexible printed film in the case of the embodiment 2 of FIG. Circuit FP
C, or in the case of the third embodiment of FIG. 3, a through hole TH is formed to connect the wiring of the bonding wire BW and the signal wiring SW. The pattern of the solid layer AW is a pattern that avoids the through hole TH, as shown in FIG.

In this embodiment, the signal wiring S on the circuit board CB is used.
W is formed by extending in parallel to the length direction of the circuit board CB (direction of arrow B), and the wiring of the tape carrier package TCP or the like is formed on the circuit board CB perpendicular to the signal wiring SW.
Are formed in parallel with each other in the width direction (direction of arrow C). Therefore, the plurality of through holes TH for connecting to the signal wiring SW are oblique to the extension direction of the wiring of the signal wiring SW and the tape carrier package TCP (or the length direction and the width direction of the circuit board CB). It is arranged. The signal wiring SW is laid out in the order of input to the integrated circuit chip.

Although the circuit board CB made of glass is used in the first to fourth embodiments, a circuit board made of plastic may be used. In particular, when the insulating substrate forming the liquid crystal display element PNL is made of plastic, if the circuit board CB is made of the same plastic material, the linear expansion coefficient of both becomes the same, and the tape carrier package TCP or the like connected between the both. It is effective because it can suppress the stress that occurs in the first place and improves the mechanical strength.

<< Active Matrix Liquid Crystal Display Device >>
An embodiment in which the present invention is applied to an active matrix type color liquid crystal display device 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.

<< 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 display window, PNL is a liquid crystal display element (liquid crystal display panel), SPB is a light diffusion plate,
MFR is an intermediate frame, BL is a backlight, BLS is a backlight support, and LCA is a lower case, and the modules MDL are assembled by stacking the members in a vertical arrangement relationship as shown in the figure.

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 that an opening corresponding to the display window LCW is provided, and the frame portion has a diffusion plate SPB, a backlight support BLS, and various circuit components in accordance with the shapes and thicknesses thereof. There are irregularities and openings for heat dissipation.

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

The drive circuit board CB1 of the module MDL shown in this figure is made of the same glass as the material of the liquid crystal display element PNL, and the wiring of the drive circuit board CB1 is patterned by the photoetching technique. Therefore, since the wiring density can be improved, the drive wiring board CB1
Can be reduced in size, which is advantageous for miniaturization of the module MDL and can improve reliability against heat stress.

<< Outline of Matrix Section >> FIG. 6 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. 6 is a cross-sectional view taken along the line 3-3 of FIG. 6), and is a cross-sectional view showing the vicinity of the liquid crystal display element angle and the vicinity of the video signal terminal portion on both sides.

As shown in FIG. 6, 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. 7, a thin film transistor TFT and a transparent pixel electrode ITO1 are formed on the lower transparent glass substrate SUB1 side based on the liquid crystal layer LC, and a color filter FIL and a light-shielding film are formed 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 surface (liquid crystal LC side) 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.

<< Thin Film Transistor TFT >> Next, referring to FIG.
Returning to FIG. 7, 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 has a shape protruding vertically 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). Gate insulating film GI
Are 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 also contributes to the electrical insulation between the scanning signal line GL 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, where the i-type semiconductor layer AS is present on the lower side and the conductive layer d2 (d3) is present on the upper side. Only left.

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
Adhesion to the ⁺ type semiconductor layer d0 is improved, and the third conductive film d
3 Al is used for the purpose of preventing diffusion of Al into the N ⁺ type semiconductor layer d0 (so-called barrier layer). As the second conductive film d2, in addition to the Cr film, refractory metals (Mo, Ti,
Ta, W) film, refractory metal silicide (MoSi ₂ , T)
_{iSi 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 5000Å (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, using the same mask or the second conductive film d2 and the third conductive film d3 as a mask, the N ⁺ type semiconductor layer is formed. d0 is removed. That is, i
The N ⁺ type semiconductor layer d0 remaining on the type semiconductor layer AS is self-aligned except for the second conductive film d2 and the third conductive film d3. At this time, the N ⁺ type semiconductor layer d0 is etched so that the entire thickness thereof is removed,
The surface of the i-type semiconductor layer AS is slightly etched, but the degree thereof 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.

The protective film PSV1 is formed so as to surround the entire matrix portion AR, and the peripheral portion has the external connection terminal DT.
Removed to expose M and GTM, and SU on the upper substrate side
A portion for connecting the common electrode COM of B2 to the lead wire INT for connecting the external connection terminal of the lower substrate SUB1 with the silver paste AGP is also removed. Regarding the thickness relationship between the protective film PSV1 and the gate insulating film GI, the former is made thicker in consideration of the protective effect, and the latter is made thin in the transconductance gm of the transistor. Therefore, the protective film PSV1 having a high protective effect is formed 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 7
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, for example, an aluminum film or a chromium film having a high light-shielding property, and in this embodiment, the chromium film is formed by sputtering to 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. 6) 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.

As shown in FIG. 6, the light-shielding film BM is also formed in a frame shape in the peripheral portion, and its pattern is formed continuously with the pattern of the matrix portion shown in FIG. There is. As shown in FIGS. 6 and 7, 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 retained inside about 0.3 to 1.0 mm from the edge of the substrate SUB2, and is formed so as to avoid the cut region of the substrate SUB2.

<< 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 faces 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.

<< Equivalent Circuit of Entire Display Device >> FIG. 8 shows a connection 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 that displays information for a CRT (cathode ray tube) from a power supply circuit or a host (upper processing unit) to obtain a plurality of divided and stabilized voltage sources from one voltage source. It is a circuit including a circuit for exchanging information for use.

Although the present invention has been specifically described based on the embodiments, the present invention is not limited to the above embodiments, and it goes without saying that various modifications can be made without departing from the scope of the invention. . For example, the fourth embodiment shown in FIG.
In the above, the signal wiring SW is provided as the lower layer wiring and the solid layer AW is provided as the upper layer wiring, but conversely, the solid layer AW may be provided as the lower layer wiring and the signal wiring SW may be provided as the upper layer wiring. Further, in the embodiments shown in FIGS. 1 to 5, the circuit board CB and the substrate forming the liquid crystal display element PNL are separately formed, but the circuit board CB and the substrate forming the liquid crystal display element PNL are separated by one. You may comprise integrally by the board | substrate of a sheet. Further, although the examples shown in FIGS. 5 to 8 are applied to the active matrix type liquid crystal display device, the present invention is also applicable to the simple matrix type liquid crystal display device.

[0085]

As described above, according to the present invention,
Since the wiring and pitch of the circuit board can be made finer and the wiring density can be increased, the external dimensions of the circuit board can be reduced, and as a result, the liquid crystal display device can be miniaturized. Further, by forming the circuit board and the substrate of the liquid crystal display element with the same material, the linear expansion coefficient of both becomes the same, so that it is possible to suppress the thermal stress generated in the electrical connection means provided between the both. The connection reliability of wiring can be improved.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing a connection between a liquid crystal display element, a circuit board, and a tape carrier package according to a first embodiment of the present invention.

FIG. 2 is a cross-sectional view showing a connection between a liquid crystal display element and a circuit board according to a second embodiment of the present invention.

FIG. 3 is a cross-sectional view showing a connection between a liquid crystal display element and a circuit board according to a third embodiment of the present invention.

4A is a partial plan view of a circuit board showing a fourth embodiment of the present invention, and FIG. 4B is a sectional view taken along the line AA of FIG.

FIG. 5 is an exploded perspective view of a liquid crystal display module according to an embodiment of the present invention.

FIG. 6 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. 7 is a cross-sectional view showing the vicinity of a liquid crystal display element 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 circuit diagram including a matrix portion of an active matrix type color liquid crystal display device and its periphery.

FIG. 9 is a cross-sectional view showing a connection between a conventional liquid crystal display element, a printed circuit board, and a tape carrier package.

[Explanation of symbols]

PNL ... Liquid crystal display element, CB ... Circuit board, TCP ... Tape carrier package, ACF ... Anisotropic conductive film, CHI
... integrated circuit chip, FPC ... flexible printed circuit, BW ... bonding wire, SW ... signal wiring, PAS1, PAS2 ... passivation film, AW ...
Solid layer, TH ... through hole.

 ─────────────────────────────────────────────────── ─── Continuation of front page (72) Inventor Toru Watanabe 3300 Hayano, Mobara-shi, Chiba Hitachi, Ltd. Electronic Devices Division

Claims (11)

[Claims] 1. Two insulating substrates made of glass or plastic are superposed with a predetermined gap therebetween so that the surfaces provided with the transparent pixel electrodes and the alignment film face each other, and the insulating substrates are provided around the edge between the two substrates. A liquid crystal display element formed by bonding the two substrates with a frame-shaped sealing material and sealing liquid crystal between the two substrates inside the sealing material, and a semiconductor integrated circuit for driving the liquid crystal display element. In a liquid crystal display device including a chip and a circuit board for driving the liquid crystal display element, the circuit board is made of glass or plastic, and the wiring of the circuit board is patterned by a photoetching technique. Liquid crystal display device. 2. An insulating substrate made of two pieces of glass or plastic is superposed with a predetermined gap so that the surfaces provided with the transparent pixel electrode and the alignment film are opposed to each other, and the insulating substrates are provided around the edge between the both substrates. A liquid crystal display element formed by bonding the two substrates with a frame-shaped sealing material and sealing liquid crystal between the two substrates inside the sealing material, and a semiconductor integrated circuit for driving the liquid crystal display element. In a liquid crystal display device including a chip and a circuit board for driving the liquid crystal display element, the circuit board is made of glass or plastic, and wiring of the circuit board is patterned by a photoetching technique, and the liquid crystal The display element and the circuit board are electrically connected by a tape carrier package on which the semiconductor integrated circuit chip is mounted. The liquid crystal display device. 3. Two insulating substrates made of glass or plastic are superposed at a predetermined gap so that the surfaces provided with the transparent pixel electrodes and the alignment film face each other, and the insulating substrates are provided around the edge between the two substrates. A liquid crystal display element formed by bonding the two substrates with a frame-shaped sealing material and sealing liquid crystal between the two substrates inside the sealing material, and a semiconductor integrated circuit for driving the liquid crystal display element. In a liquid crystal display device including a chip and a circuit board for driving the liquid crystal display element, the circuit board is made of glass or plastic, and the wiring of the circuit board is patterned by a photoetching technique. The semiconductor integrated circuit chip is mounted on the surface of one of the insulating substrates, and the one of the insulating substrate and the circuit substrate is a flexible print. The liquid crystal display device characterized by being electrically connected by a circuit or the bonding wire. 4. The liquid crystal display device according to claim 1, 2 or 3, wherein one of the insulating substrate and the circuit substrate which constitute the liquid crystal display element is made of the same material. 5. The liquid crystal display device according to claim 1, wherein one of the insulating substrate and the circuit substrate forming the liquid crystal display element is made of one substrate made of the same material. 6. The liquid crystal display device according to claim 1, wherein the wiring of the circuit board is provided in multiple layers via an insulating film. 7. The liquid crystal display device according to claim 6, wherein one of the wirings is a solid layer which is connected to the ground or to which a predetermined voltage of a DC power source is applied. 8. A drive wiring is provided as a lower layer wiring on the circuit board, the solid layer is provided as an upper layer wiring via an insulating film, and an insulating film is provided thereon. The liquid crystal display device according to claim 6, which is characterized in that. 9. A drive wiring is provided as a lower wiring on the circuit board, the solid layer is provided as an upper wiring via a first insulating film, and a second insulating film is provided thereon. An opening is provided in the first insulating film and the second insulating film in a direction perpendicular to the surface of the circuit board,
7. The liquid crystal display device according to claim 6, wherein the connection terminal of the drive wiring is exposed, and the solid layer has a pattern that avoids the opening. 10. A drive wiring is provided as a lower wiring on the circuit board, the solid layer is provided as an upper wiring via a first insulating film, and a second insulating film is provided thereon. An opening is provided in the first insulating film and the second insulating film in the direction perpendicular to the circuit board surface, and a connection output terminal of the drive wiring is exposed in the opening, and The solid layer has a pattern for avoiding the opening, and the plurality of connection output terminals respectively extend in a first linear direction in a plane parallel to the circuit board surface,
The plurality of connecting input terminals of the tape carrier package or the flexible printed circuit connected to the connecting output terminal crosses the first linear direction in a plane parallel to the circuit board surface. 7. The opening extending in a linear direction and exposing the connecting output terminal is arranged obliquely with respect to the first linear direction or the second linear direction. Liquid crystal display device. 11. The connection terminal portion and the tape carrier package or the flexible printed circuit are electrically connected to each other through an anisotropic conductive film. Liquid crystal display device.