JPH0268524A - Liquid crystal display device - Google Patents

Abstract

PURPOSE:To prevent the corrosion of the wiring connected to external driving circuit even if the liquid crystal display device is operated in a high-temp. and high-humidity state by coating the part corresponding to the end part of a protective film for protecting the wiring connected to the external driving circuit with a non-water permeable resin. CONSTITUTION:The part corresponding to the end of the protective film 1 of the wiring 8 for connecting the liquid crystal display device formed by crimping a liquid crystal LC between upper and lower transparent glass substrates 1 and 2 to the external driving circuit is coated with the epoxy resin 7. The resin 7 may be resins except the epoxy resin as far as the resins are non-water permeable. Since the part corresponding to the protective film 1 end of the wiring 8 is coated with the non-water permeable epoxy resin 7 in such a manner, the adsorption of moisture is prevented even if the display device is operated at and under a high temp. and high humidity. The corrosion of the part corresponding to the protective film 1 end of the wiring 8 is, therefore, obviated and the disconnection of the wiring 8 is prevented.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a liquid crystal display device such as an active matrix type color liquid crystal display device in which a thin film transistor (TPT) and a pixel electrode are used as constituent elements of a pixel. It is related to.

[Conventional technology]

FIG. 9 is a sectional view showing a part of a conventional active matrix color liquid crystal display device.

In the figure, 5UB1 is the lower transparent glass substrate, 5UB2
is the upper transparent glass substrate, LC is the liquid crystal, SL is the sealing material,
8 is a wiring made of Cr, 1 is a protective film for the wiring 8, and the protective film 1 is made of SiN and is formed by plasma CVD. 2 is an oxide conductive film formed on the end of the wiring 8, and the oxide conductive film 2 is made of indium oxide (ITO) containing tin oxide.
Consisting of

3 is a flexible printed circuit board, 4 is a conductor pattern of the flexible printed circuit board 3, and one end of the conductor pattern 4 is connected to an external drive circuit (not shown). 5 is an anisotropic conductive agent that connects the other end of the conductor pattern 4 and the oxide conductive film 2; 6 is a silicone resin filled in the space formed between the upper transparent glass substrate 5UB2 and the flexible printed circuit board 3; It is.

In this liquid crystal display device, the silicone resin 6 can prevent dirt from adhering to the outer side of the sealing material SL, and since the silicone resin 6 has elastic force, no force is applied to the upper transparent glass substrate 5UB2, etc. can be prevented from acting.

[Problem to be solved by the invention]

However, in such a liquid crystal display device, since the silicone resin 6 has water permeability, the temperature is high.

When operated at high temperatures, moisture may be adsorbed to the portion of the wiring 8 corresponding to the end of the protective film 1, corroding the portion of the wiring 8 corresponding to the end of the protective film 1, and the wiring 8 may be disconnected.

This invention was made to solve the above-mentioned problems, and its purpose is to provide a liquid crystal display device in which the wiring connected to an external drive circuit does not corrode even when operated at high temperatures. do.

[Means to solve the problem]

To achieve this object, in the present invention, in a liquid crystal display device in which wiring connected to an external drive circuit is protected with a protective film, a portion of the wiring corresponding to the end of the protective film is coated with a non-water permeable resin. to be covered.

Moreover, in order to achieve the above object, in this invention,
In a liquid crystal display device in which wiring connected to an external drive circuit is protected by a protective film, an end of the protective film is positioned on an oxide conductive film formed on the wiring.

[Effect]

In these liquid crystal display devices, even when operated at high temperatures and high humidity, water-impermeable resin and oxide conductive films prevent moisture from adsorbing to the portions corresponding to the ends of the protective film of the wiring. be able to.

〔Example〕

One pixel and its surroundings in the liquid crystal display section of an active matrix type color liquid crystal display device which is an embodiment of the present invention are shown in FIG. 2 (main part plan view). A partial cross section is shown in Figure 3, and 4A in Figure 2.
-4A and 4B-4B cross sections, respectively.
Shown in Figures A and 4B. Also, in Figure 5 (plan view of main parts),
2 shows a main part of a liquid crystal display section in which a plurality of pixels shown in FIG. 2 are arranged.

As shown in FIGS. 2 to 5, the liquid crystal display device includes a
A pixel includes a thin film transistor TPT and a transparent pixel electrode PIX.

The lower transparent glass substrate SUB 1 has, for example, 1.1 [
1Ilffi].

Each pixel is located within the intersection area (4 (within the area surrounded by the signal lines). As shown in FIGS. 2 and 5, the scanning signal lines GL extend in the column direction, and a plurality of scanning signal lines GL are arranged in the row direction. The video signal lines DL extend in the row direction, and a plurality of video signal lines DL are arranged in the column direction.

The m-film transistor TPT mainly includes a gate electrode GT, an insulating film GI, and a type 1 (intrinsic, not doped with conductivity type determining impurity) amorphous Sj semiconductor layer A.
S, a pair of source electrode SDI and drain electrode SD2
It is made up of. Note that the source and drain are originally determined by the bias polarity between them, and in the circuit of this display device, the polarity is reversed during operation, so it should be understood that the source and drain are interchanged during operation. However, in the following explanation as well, for convenience, one side is fixed as a source and the other side is fixed as a drain.

As shown in the plan view of FIG.
(drawn at the lower left and lower right), it is configured in a 7-shape (branched into a T-shape) that protrudes in the row direction (upward in FIG. 2) from the scanning signal line GL. That is, the gate electrode GT is configured to extend substantially parallel to the video signal line DL. The gate electrode GT is N
r! It is formed continuously to the scanning signal line OL so as to protrude to the formation region of the a-transistor TFT.

As shown in FIG. 2, the gate electrode GT is formed to be thicker than the semiconductor MAs so as to completely cover it (as viewed from below). Therefore, when a backlight such as a fluorescent lamp is installed below the substrate 5UBI, the opaque Cr gate electrode GT casts a shadow, and the backlight light does not shine on the semiconductor layer AS, causing the conductive phenomenon caused by light irradiation described above. In other words, deterioration of the TPT off-characteristics becomes less likely to occur. The original size of the gate electrode GT is the minimum width required to span between the source/drain electrodes SDI and SC2 (including the alignment margin between the gate electrode and the source/drain electrodes), and the channel width. The depth that determines W is the distance between the source and drain electrodes (channel length)
It is determined by the factor W/L that determines the ratio to L, that is, the mutual conductance &m.

The size of the gate electrode in this embodiment is of course larger than the original size mentioned above.

Note that, if necessary, light shielding of the transistors TPTI-3, etc. from the substrate 5UB2 side can be achieved by providing a pattern such as a chromium layer, a pattern of an organic filter layer, etc. on the substrate 5UB2 side.

Source/drain electrode SD1. SD2 is 1 type 5iJWA
The gate electrode GT is in non-rectifying contact with S via a high concentration N-type Si layer N", and a gate electrode GT is arranged below it via a gate insulating film GI so as to straddle both electrodes.

The width of the scanning signal line GL is increased between two adjacent video signal lines 05 (it swells downward in Figure 2).
This expanded portion is the capacitor Cadd.
constitutes one electrode (lower electrode OL). The other electrode of the capacitor Cadd is located above it and is composed of an electrode (upper electrode CH) formed of a layer at the same level as the source/drain electrodes SDI and SC2. As is clear from the cross-sectional structure shown in FIG. 4B, the capacitor Cacld is sandwiched between the above-mentioned upper and lower capacitors [CH, CL and #! It is composed of the lamina GI. The high concentration S i M N+ located below the upper electrode CH functions as an electrode plate in terms of capacitor function, and hereinafter the upper electrode CH and the N+ layer are collectively referred to as the upper electrode CH. The above-mentioned insulator GI is patterned so as to be interrupted at the left end portion of the figure, thereby allowing the upper electrode CH to come into ohmic contact with the pixel electrode PIX. Therefore, this capacitor Ca
cid is TPT driven by a certain scanning line OL (lower side)
It is formed between the pixel electrode PIX connected to the pixel electrode PIX and the adjacent scanning line OL (upper side). The capacitor Cadd is
It is possible to reduce electrostatic noise caused by the parasitic capacitance formed between the gate electrode GT and source electrode SDI and changes in the scanning pulse applied to the scanning line GL, and to reduce the storage time of video information after the TPT is turned off. It works for a long time, and is connected substantially in parallel with the liquid crystal capacitor, which is composed of the liquid crystal layer LC and the counter electrodes (PIX, IrO2) sandwiching it, in terms of alternating current.
It acts as an auxiliary capacity, so to speak.

Next, the overall structure of the liquid crystal display panel will be explained with reference to FIG.

A protective film PSVI is provided over the thin film transistor TPT and the transparent pixel electrode PIX.

The protective film PSVI is mainly formed to protect the thin film transistor TPT from moisture, etc., and a film having high transparency and good moisture resistance is used.

The protective film PSVI is formed of, for example, a silicon oxide film or a silicon nitride film formed by plasma CVD, and
Formed with a film thickness of about [a person].

The thin film transistor TPT is configured such that when a positive bias is applied to the gate electrode GT, the channel resistance between the source and the drain decreases, and when the bias is reduced to zero, the channel resistance increases.

The liquid crystal LC is sealed between the lower transparent glass substrate 5tJB1 and the upper transparent glass substrate 5UB2, between a lower alignment film 0RII and an upper alignment film 0RI2 that set the orientation of liquid crystal molecules.

The lower alignment film 0RII is formed on the protective film PSVI on the side of the lower transparent glass substrate 5UBI.

On the inner surface (liquid crystal side) of the upper transparent glass substrate 5UB2, a color filter FIL, a protective film PSv2, a common transparent electrode (COM) ITO2, and the upper alignment film ○RI2 are disposed.
are sequentially stacked.

The common transparent electrode COM is connected to a lower transparent glass mounting plate 5UB.
It faces the transparent pixel electrode PIX provided for each pixel on the I side, and is configured to be common to a plurality of pixel electrodes prx. The common transparent electrode COM is configured to be applied with a common voltage Vcom. The common voltage V com is a low level drive voltage Vdm1n applied to the video signal line DL and a high level drive voltage V d
It is an intermediate potential between max and max.

The color filter FIL is configured by coloring a dyed base material made of a resin material such as acrylic resin with a dye.

The color filter FIL is arranged for each pixel at a position facing the pixel, and is colored differently. That is, the color filter FIL, like the pixel, is configured within the intersection area of two adjacent scanning signal lines OL and two adjacent video signal lines DL.

Color filter FIL can be formed as follows. First, a dyed base material such as gelatin is formed on the surface of the upper transparent glass substrate 5UB2, and the dyed base material other than the red filter formation area is removed using photolithography technology.

After this, the dyed base material is dyed with red dye, fixed treatment is applied,
A red filter R is formed. Next, a green filter G and a blue filter B are sequentially formed by performing similar steps.

In this way, by forming each color filter of the color filter FIL in the intersection region facing each pixel, each of the scanning signal line GL and the video signal line DL is present in each color filter l'fj17 of the color filter FIL. So,
Each pixel and color filter F correspond to their existence.
Ensure enough alignment allowance for each color filter of IL (
(increase the alignment margin). Furthermore, when forming each color filter of the color filter FIL, it is possible to ensure alignment margin between different color filters.

The protective film PSV2 is provided to prevent the dye contained in the color filter FIL from leaking into the liquid crystal LC. The protective film PSV2 is made of, for example, a transparent resin material such as acrylic resin or epoxy resin.

This liquid crystal display device has a lower transparent glass substrate 5UBl side,
Each layer on the upper transparent glass substrate 5UB2 side is formed separately, and then the upper and lower transparent glass substrates 5UBI and 5UB are formed separately.
2 are stacked on top of each other and a liquid crystal LC is sealed between the two.

The central part of FIG. 3 shows a cross section of one pixel part, while the left side shows a cross section of a part where external lead wiring is present at the left edge part of the transparent glass substrates 5UBI and 5UB2.

The right side shows a cross section of the right edge portion of the transparent glass substrates 5UBI and 5UB2 where no external lead wiring is present.

The sealing material SL shown on the left and right sides of FIG. 3 is configured to seal the liquid crystal LC.

Transparent glass substrate 5 excluding the liquid crystal filling port (not shown)
It is formed along the entire periphery of UBI and 5UB2. The sealing material SL is made of, for example, epoxy resin.

Common transparent electrode CO on the upper transparent glass substrate 5UB2 side
M is silver paste material SIL in at least one place
It is connected to an external lead wiring formed on the lower transparent glass substrate 5UBI side. This external wiring is
The transparent electrode layer is made of ITOI.

The alignment films 0RII and ○RI2, the transparent pixel electrode PI
X, the common transparent electrode COM is formed inside the sealing material SL. The polarizing plate POL has a lower transparent glass substrate 5UBI
, are formed on the outer surface of each of the upper transparent glass substrates 5UB2.

As shown in FIG. 5, a plurality of pixels of the liquid crystal display section are arranged in the same column direction as the direction in which the scanning signal line GL (Yi) extends, and the pixel columns A i , A i +1° Ai +2 .
It constitutes each of... Each pixel column Ai.

A i +l, A i +2. . . . each pixel has the same arrangement position of the thin film transistor TPT and the transparent pixel electrode PIX. In other words, pixel row Ai+
In each pixel of 1°Ai+3 (not shown), . . . , the thin film transistor TPT is arranged on the left side, and the transparent pixel electrode PIX is arranged on the right side. Pixel row A i
+1. Ai+3. . . , adjacent pixel columns Ai in the row direction, Ai÷2. Each pixel of... is in pixel column A
x +l, A l +3. . . . are arranged line-symmetrically with respect to the video signal line DL. That is, 1 pixel row Ai, Ai+2. ...
In each pixel, the thin film transistor TPT is arranged on the right side, and the transparent pixel electrode PX is arranged on the left side. Then, pixel rows Ai, Ai+2. Each pixel of . . . is a 9-pixel column Ai+1. Ai+3. Move (shift) each pixel of ... by half a pixel in the direction of one column.
It is located. In other words, each pixel interval of pixel row Ai is set to 1
．． 0 (1,0 pitch), the next pixel column Ai+
1, each pixel interval is 0, and is shifted by 0.5 pixel interval (0.5 pitch) in the column direction with respect to the previous pixel column Ax. Video signal line DL (X
i) is a half pixel interval (0, 5
It is configured to extend in the column direction.

In this way, in the liquid crystal display section, the thin film transistor T
A pixel row A is constructed by arranging a plurality of pixels with the same PT and transparent pixel electrode IT○ in the column direction. It is composed of pixels arranged line-symmetrically with respect to the signal line DL, and by moving the next pixel column by half a pixel interval with respect to the previous pixel column, it is possible to As shown in the main part plan view in the superimposed state).

A pixel in the previous pixel row A on which a predetermined color filter is formed (for example, a pixel on which a red filter R is formed in the pixel row Ai) and a pixel in the next pixel row A on which the same color filter is formed (for example, a pixel on which the same color filter is formed) (the pixel in column Ai+1 where the red filter R is formed) can be separated by 1.5 pixel intervals (1.5 pitch). In other words, the pixels in the previous pixel row A are always separated by 1.5 pixel intervals from the nearest pixel in the next pixel row on which the same color filter is formed, and the color filter FIL can configure an RGB triangular arrangement structure. Color filter FI
The triangular arrangement structure of RGB of L can improve the color mixing of each color, and therefore can improve the resolution of a color image.

Further, the video signal line DL extends in the column direction only by half a pixel interval between each pixel column A.

It no longer intersects with the adjacent video signal line DL. Therefore, it is possible to eliminate the routing of the video signal line DL and reduce the area occupied by the video signal line DL, and it is also possible to eliminate the detour of the video signal line DL and eliminate the multilayer wiring structure.

FIG. 1 is a sectional view showing a part of an active matrix color liquid crystal display device according to the present invention. In this liquid crystal display device, a portion of the wiring 8 corresponding to the end portion of the protective film 1 is coated with an epoxy resin 7. Therefore, even when operating at high temperatures and high humidity, the epoxy resin 7 can prevent moisture from adsorbing to the portion of the wiring 8 corresponding to the end of the protective film 1, thereby protecting the wiring 8. The portion corresponding to the end of the film 1 will not corrode, and the wiring 8 will not be disconnected. According to the inventors' experiments, at 40℃, 95% high temperature, and high humidity, 10
Even after operating for more than 00 hours, the portion of the wiring 8 corresponding to the end of the protective film 1 was not corroded at all.

FIG. 7 is a sectional view showing a part of another active matrix type color liquid crystal display device according to the present invention.

In this liquid crystal display device, the protective film 1a extends between the oxide conductive TM2 and the anisotropic conductive agent 5,
An end portion of the protective film 1 a is located on the oxide conductive film 2 .

Therefore, even when operating at high temperature and high humidity, the oxide conductive film 2 can prevent moisture from adsorbing to the portion of the wiring 8 corresponding to the end of the protective film 1a. The portion corresponding to the end of the protective film 1a will not corrode, and the wiring 8 will not be disconnected.

FIG. 8 is a sectional view showing a part of another active matrix type color liquid crystal display device according to the present invention.

In this liquid crystal display device, the oxide conductive film 2a extends between the wiring 8 and the protective film 1, and the end of the protective film 1 is located on the oxide conductive film 2a. For this reason,
Even if the wiring 8 is operated at high temperature and high humidity, the oxide conductive film 2a can prevent moisture from adsorbing to the portion of the wiring 8 corresponding to the end of the protective film 1.
The part corresponding to the upper edge of the protective film will not corrode.
The wiring 8 will not be disconnected.

Note that the above-mentioned oxide conductive film is the same layer as the transparent conductive film ITOI shown in FIGS. 2 to 4B, so that the number of manufacturing processes is not increased.

In the above embodiments, an active matrix color liquid crystal display device has been described, but the present invention can also be applied to other liquid crystal display devices. Further, in the above embodiments, an epoxy resin was used as the water-impermeable resin, but other water-impermeable resins may be used.

〔Effect of the invention〕

As explained above, in the liquid crystal display device according to the present invention, even if it is operated at high temperature and high humidity, it is possible to prevent moisture from adsorbing to the portion corresponding to the end of the protective film of the wiring. Therefore, the portion of the wiring corresponding to the end of the protective film will not be corroded, and the wiring will not be disconnected.

As described above, the effects of this invention are remarkable.

[Brief explanation of the drawing]

FIG. 1 is a sectional view showing a part of an active matrix color liquid crystal display device according to the present invention, and FIG. 2 is a sectional view of a liquid crystal display section of an active matrix color liquid crystal display device according to an embodiment of the present invention. FIG. 3 is a partial cross-sectional view of the color liquid crystal display device shown in FIG. 2; FIG.
4A, sectional view taken along the 4B-4B cutting line, Figure 5 is the 2nd
A plan view of the main parts of a liquid crystal display section in which a plurality of pixels are arranged as shown in the figure,
FIG. 6 is a plan view of main parts in a state in which the pixels and color filters shown in FIG. FIG. 9 is a sectional view showing a part of a conventional active matrix color liquid crystal display device. 1.1a...Protective film 2.2a...Oxide conductive film 7...Epoxy resin 8...Wiring agent Patent attorney Junnosuke Nakamura 1...-Protective film 2...Oxide conductive film Film 7 - Niboxy resin 8... Wiring Figure 4A Figure 4B Figure 1a... Protective film 2... Oxide 91 Conductive film 8... Wiring 1... Protective film 2a... Oxide conductive film 8...Wiring

Claims (1)

[Claims] 1. In a liquid crystal display device in which wiring connected to an external drive circuit is protected by a protective film, a portion of the wiring corresponding to the end of the protective film is coated with a water-impermeable resin. Characteristic liquid crystal display device. 2. A liquid crystal display device in which wiring connected to an external drive circuit is protected by a protective film, characterized in that an end of the protective film is located on an oxide conductive film formed on the wiring. LCD display device. 3. The liquid crystal display device according to claim 2, wherein the oxide conductive film is a layer on the same level as a transparent conductive film serving as a pixel electrode of the display section.