JP2001154205A - Active matrix liquid crystal display device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an active matrix liquid crystal display device with a high aperture ratio and excellent display quality. SOLUTION: Scanning lines 62 and signal lines 50 are arranged in a matrix and simultaneously auxiliary capacitance lines 52 in parallel with the scanning lines, TFTs(thin film transistors) 28 and stripe-shaped coloring layers of three colors are arranged on an array substrate. Pixel electrodes 51 are arranged on the respective coloring layers and connected to the corresponding TFTs through contact holes 81a, 81b and 81c formed on the coloring layers. Also plural post spacers 36 are arranged on the array substrate. The respective post spacers are placed on the boundary parts between the adjacent two coloring layers and arranged between the two adjacent contact holes.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an active matrix type liquid crystal display device in which display pixel electrodes are formed by using thin film transistors (hereinafter referred to as TFTs) as switching elements.

[0002]

2. Description of the Related Art In recent years, while having a high density and a large capacity,
Practical use of liquid crystal display devices capable of obtaining high-performance and high-definition display has been promoted. There are various types of liquid crystal display devices. Among them, an active matrix type liquid crystal display device is preferred because of its small crosstalk between adjacent pixels, high-contrast display, transmission-type display, and easy area enlargement. Liquid crystal display devices are widely used.

In this active matrix type liquid crystal display device, TFs are formed in a plurality of areas defined by a plurality of scanning lines and a plurality of signal lines provided in directions crossing each other.
An array substrate having pixel electrodes provided in a matrix using T as a switching element is provided.

A color filter made of a colored layer having a thickness of 2 to 4 microns is provided on an array substrate, and a pixel electrode formed thereon and a source electrode of a TFT element formed below are connected via a contact hole. Attempts have been made to enable color display. In this case, since the coloring layer conventionally provided on the counter substrate side can be formed on the array substrate side, a good color display independent of the assembly accuracy of the array substrate and the counter substrate can be obtained.

[0005] Attempts have also been made to form a spacer for holding a gap between the array substrate and the opposing substrate in a non-display portion on the array substrate. In this case, by forming the spacer on a flat portion of the coloring layer, a favorable display with high contrast can be obtained.

[0006]

However, the thickness of the colored layer is as large as 2 to 4 microns, and a contact for connecting a pixel electrode formed above the colored layer to a source electrode of a TFT formed below the colored layer. It is difficult to finely process the hole. When the pixel pitch becomes smaller, the diameter of the contact hole becomes about half of the width of the stripe-shaped colored layer, and the contact hole provided on the colored layer and the contact hole provided on the colored layer of the adjacent pixel are formed. Of the colored layer for forming the spacers becomes smaller.

Therefore, in order to provide a spacer in a flat region of the colored layer, the contact hole and the spacer must be arranged on the monochromatic colored layer in the longitudinal direction of the colored layer. In addition, the metal wiring provided below the spacer becomes thick, and the aperture ratio is significantly reduced.

The present invention has been made in view of such a problem, and an object of the present invention is to prevent a decrease in aperture ratio.
An object of the present invention is to provide an active matrix liquid crystal display device having high display quality.

[0009]

In order to achieve the above object, a liquid crystal display device according to the present invention comprises a plurality of scanning lines provided on an insulating substrate and a plurality of scanning lines provided intersecting the scanning lines. A switching element provided near each intersection of the scanning line and the signal line, a plurality of auxiliary capacitance lines provided to intersect with the signal line, the scanning line, the signal line, A plurality of stripe-shaped colored layers covering the auxiliary capacitance lines and the switching elements; a plurality of pixel electrodes connected to the switching elements and formed on the colored layers; and arranged on the colored layers. An array substrate having a plurality of columnar spacers,
A counter substrate disposed opposite to the array substrate with a predetermined gap provided by the column spacer, and a liquid crystal layer sealed in a gap between the array substrate and the counter substrate; each of the column spacers Is characterized in that it is provided so as to overlap the boundary between two adjacent colored layers.

Further, according to the liquid crystal display device of the present invention, each of the coloring layers has a contact hole for connecting each of the pixel electrodes and the switching element, and each of the columnar spacers is adjacent to each other. The two colored layers are provided between two contact holes adjacent to each other.

According to the liquid crystal display device having the above structure, the columnar spacer for maintaining the gap between the array substrate and the counter substrate is provided at the boundary between two adjacent colored layers, ie, between the colored layer and the adjacent colored layer. Are provided in the overlapping portion of the. In addition, the columnar spacers are provided in gaps between contact holes provided in adjacent coloring layers. Therefore, the contact holes and the columnar spacers can be efficiently arranged on the metal wiring, and a higher aperture ratio can be obtained. Thus, the transmittance can be improved, and a liquid crystal display device which is bright and consumes less power can be realized.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, an active matrix type liquid crystal display device according to an embodiment of the present invention will be described in detail with reference to the drawings. As shown in FIGS. 1 to 3, the liquid crystal display device 10 includes an array substrate 12 provided with a coloring layer as a color filter, and a counter substrate 20 which is disposed facing the array substrate with a predetermined cell gap. , And a liquid crystal layer 90 is sandwiched between the array substrate and the counter substrate.

The periphery of the array substrate 12 and the counter substrate 20 are joined to each other by a sealing material 19 arranged so as to surround the outer periphery of the display area 40 of the liquid crystal display device. A liquid crystal injection port 35 is formed in a part of the sealing material 19, and the liquid crystal injection port 35 is sealed with a sealing material 33 after the liquid crystal is injected.

The opposing substrate 20 is formed by sequentially forming a transparent electrode 86 made of ITO and an alignment film 89 on a transparent substrate 84 made of glass.

As shown in FIGS. 2 and 3, the array substrate 12 having a color filter includes a transparent substrate 60 made of glass, on which a plurality of scanning lines 62 and a plurality of scanning lines 62 are provided in parallel. The auxiliary capacitance wiring 52 and the signal line 50 orthogonal to these via an insulating film 75 are arranged. In the vicinity of each intersection between the scanning line 62 and the signal line 50, a Tch of an Nch LDD structure is used as a switching element.
FT28 is connected. Each region surrounded by the auxiliary capacitance wiring 52 and the signal line 50 has a pixel electrode 51
Are connected to the source electrode of the TFT 28.

At the same time as the TFT 28, the display area 40
A liquid crystal driving circuit is formed in the periphery, and TFTs 30 and 31 and a plurality of wirings are provided in the vicinity of the display area to operate the liquid crystal driving circuit.

Then, a protective insulating film 79 is provided so as to cover the TFT 28 and the liquid crystal driving circuit, and a green colored layer 25G, a blue colored layer 25B, and a red colored layer 25R each having a stripe shape made of an organic insulating film are provided thereon. Are located. The pixel electrode 51 is disposed on these coloring layers, and the source of the TFT 28 via the contact holes 81 a, 81 b, 81 c formed in the coloring layer and the protective insulating film 79 and the upper electrode 78 of the auxiliary capacitance wiring 52. It is connected to the electrode 67. Further, an alignment film 88 is disposed on the entire surface of the transparent substrate 60 so as to cover the pixel electrode 51 and the coloring layer.

On the glass substrate 60 of the array substrate 12, a rectangular frame pattern 32 made of a black colored layer having a predetermined width is formed so as to surround the outer peripheral edge of the display area 40. The frame pattern 32 is formed thicker than the other colored layers 25G, 25B, 25R. Further, at the same time as the frame pattern 32, the auxiliary capacitance wiring 52
A large number of columnar spacers 36 are formed at a desired density on the top. Each columnar spacer 36 is provided on an overlapping portion of two adjacent coloring layers, that is, on a boundary portion.
Holes 81a, 81 provided in the two colored layers
b, 81c.

The array substrate 12 and the opposing substrate 2
Numeral 0 indicates that the peripheral portions are adhered to each other by the sealing material 19, and the cell gap between these substrates is maintained at a predetermined value by a large number of columnar spacers 36.

Next, a more detailed structure of the active matrix type liquid crystal display device will be described together with a manufacturing method thereof. First, an a-Si film is formed on a light transmitting insulating substrate 60 such as a high strain point glass substrate or a quartz substrate by a CVD method or the like.
Deposit about 0 nm. This was annealed in a furnace at 450 ° C. for 1 hour, and then irradiated with a XeCl excimer laser to obtain a-
The Si film is polycrystallized to form a polysilicon film. Then,
The polysilicon film is patterned by a photoetching method to form a channel layer of a TFT 28 (hereinafter, referred to as a pixel TFT) in a pixel portion in a display region and TFTs 30 and 31 (hereinafter, referred to as a circuit TFT) in a liquid crystal drive circuit region. A channel layer is formed.

Next, a silicon oxide film 61 serving as a gate insulating film is formed to a thickness of 100 nm on the entire surface of the insulating substrate 60 by the CVD method.
To a degree. Subsequently, a single element such as Ta, Cr, Al, Mo, W, Cu, or a laminated film or an alloy film thereof is deposited on the entire surface of the silicon oxide film 61 to a thickness of about 400 nm, and is patterned into a predetermined shape by a photoetching method. The scanning line 62, the gate electrode 63 of the pixel TFT 28 extending the scanning line, the gate electrodes 64 and 65 of the circuit TFTs 30 and 31, the auxiliary capacitance wiring 52, and various wirings in the drive circuit area are formed.

Subsequently, impurities are implanted into the channel layer by ion implantation or ion doping using the gate electrodes 63, 64 and 65 as a mask, and the drain electrode 66 and the source electrode 67 of the pixel TFT 28 and the Nch type circuit TFT 31 are formed. The source electrode 69 and the drain electrode 70 are formed. The impurity is implanted at an acceleration voltage of 80 keV for 5
At a dose of × 10 ¹⁵ atoms / cm ² , PH ₃ /
Phosphorus and high concentration injected by H _2.

Next, the pixel TFT 28 and the Nch type circuit TFT 31 in the drive circuit area are covered with a resist so as not to be doped with impurities, and then the Pch type circuit TFT 3 is formed.
Using the 0 gate electrode 64 as a mask, boron is implanted at a high concentration of B ₂ H ₆ / H ₂ at an acceleration voltage of 80 keV and a dose of 5 × 10 ¹⁵ atoms / cm ² ,
The source electrode 72 and the drain electrode 73 of the ch-type circuit TFT 30 are formed.

Then, an Nch type LDD (Lighty Doped
Drains) 74a, 74b, 74c, and 74d are implanted to form impurities, and the substrate is annealed to activate the impurities. Further, an interlayer insulating film 75 made of a silicon oxide film is deposited on the entire surface of the insulating substrate 60 to a thickness of about 500 nm by using, for example, PECVD.

Subsequently, the contact hole 76 reaching the drain electrode 66 of the pixel TFT 28, the contact hole 77 reaching the source electrode 67, and the contact holes reaching the source electrode and the drain electrode of the circuit TFTs 30 and 31 are interlayer-insulated by photoetching. Formed on the film 75.

Next, Ta, Cr, A
l, Mo, W, Cu, etc., or a laminated film or alloy film of about 500 nm is deposited, patterned into a predetermined shape by a photoetching method, and the signal line 50 connected to the drain electrode 66 of the pixel TFT 28 is formed. The upper electrode 78 of the auxiliary capacitor connected to the source electrode 67 and various wirings of the circuit TFTs 30 and 31 in the liquid crystal drive circuit area are formed.

Next, a protective insulating film 79 made of SiNx is formed on the entire surface of the insulating substrate 60 by the PECVD method, and contact holes 80 respectively reaching the upper electrodes 36 are formed by the photo etching method.

Subsequently, an ultraviolet curable acrylic green resist solution is applied to the insulating substrate 60 by spinner coating to a thickness of 3 μm.
It is applied with a film thickness of about. Thereafter, pre-baking is performed at about 90 ° C. for about 5 minutes, and 150 m
Exposure is performed with ultraviolet light having an intensity of J / cm ² . The photomask pattern used here has a stripe-shaped pattern corresponding to the green coloring layer 25G and a circular pattern corresponding to the contact hole 81a for connecting the pixel electrode 51 and the upper electrode 78.

Subsequently, the contact hole 81 is developed by using an aqueous solution of TMAH (tetramethylammonium hydride) of about 0.1% by weight for about 60 seconds, washed with water, and post-baked at about 20 ° C. for about 1 hour.
A striped green colored layer 25G having a was formed.

Next, with the same configuration, a striped blue colored layer 25B having a contact hole 81b and a striped red colored layer 25R having a contact hole 81c are formed in the same steps. At this time, the pattern edge of the green coloring layer 25G was configured to be covered with the blue coloring layer 25B and the red coloring layer 25R. this is,
As described above, this is achieved by making the exposure mask used when processing each colored layer to be compatible.

Subsequently, for example, lTO is formed to a thickness of about 100 nm on the coloring layers 25R, 25G, and 25B by a sputtering method, and is patterned into a predetermined shape by a photo-etching method. At the same time, the pixel electrode 51 and the upper electrode 78 of the auxiliary capacitance line are connected.

Next, a black colored layer of about 5 μm is applied to the entire surface and patterned, so that the frame pattern 32 surrounding the outer periphery of the display area 40 and the boundary between the adjacent striped colored layers are formed. A plurality of columnar spacers 36 located respectively are formed.

Thereafter, an alignment film material made of polyimide was applied to the entire surface of the insulating substrate 60, and an alignment process was performed to form an alignment film 88, thereby obtaining an array substrate 12 having a color filter.

On the other hand, ITO is deposited to a thickness of about 100 nm on the transparent insulating
6, an alignment film material made of polyimide is applied to the entire surface of the substrate, and an alignment process is performed to form an alignment film 89, whereby the counter substrate 20 is obtained.

The sealing material 19 is applied to the outer peripheral portion of the counter substrate 20 formed as described above except for the liquid crystal injection port 35. The opposing substrate 20 and the array substrate 12 provided with the color filters are bonded together on the outer peripheral side of the frame pattern 32 with the sealing material 19, whereby an empty cell is completed.

Next, a nematic liquid crystal material to which a chiral material has been added is vacuum-injected into the cell from the liquid crystal injection port 35, and after the injection, the liquid crystal injection port 35 is sealed using an ultraviolet curable resin as a sealing material 33. Stop. Thereafter, a polarizing plate (not shown) is attached to both sides of the cell, whereby the liquid crystal display device 10 is completed.

The liquid crystal display device 10 configured as described above
According to this, each columnar spacer 36 is provided on the boundary between the adjacent stripe-shaped colored layers and the contact holes 81 formed in these colored layers.
a, 81b, 81c. Therefore, the columnar spacers 36 and the contact holes can be efficiently arranged on a metal wiring such as the auxiliary capacitance wiring 52, so that the metal wiring can be formed thinner as compared with the related art.

Accordingly, even in a high-definition active matrix type liquid crystal display device having a fine pixel pitch, it is not necessary to arrange the columnar spacers 36 in the longitudinal direction of the coloring layer and the contact holes, and a high aperture ratio can be obtained.
A bright and low power consumption liquid crystal display device can be obtained.

The present invention is not limited to the above-described embodiment, but can be variously modified within the scope of the present invention. For example, as in the second embodiment shown in FIG.
Each of the contact holes 81a, 81b, 81c is not limited to a circular shape, and may be formed in a vertically long elliptical shape. That is, the cross-sectional shape of each contact hole is formed such that the diameter of the stripe-shaped colored layer along the width direction is smaller than the diameter of the colored layer along the longitudinal direction.

According to such a configuration, even in a high-definition active matrix type liquid crystal display device with a fine pixel pitch, a sufficient installation space for providing a columnar spacer between adjacent contact holes can be ensured. And a high aperture ratio can be obtained.

Further, as in the third embodiment shown in FIG. 5, each columnar spacer 36 may be formed in an elongated elliptical cross section extending along the longitudinal direction of the striped colored layer. . Even in such a configuration, a high aperture ratio can be obtained as in the above-described embodiment.

Further, as shown in FIG. 6, a substantially elliptical contact hole 81 extending along the longitudinal direction of the colored layer.
The same effect can be obtained by simultaneously employing a, 81b, 81c and the columnar spacer 36 having a substantially elliptical cross section.

In the embodiment shown in FIGS. 4 to 6, the other structure is the same as that of the above-described first embodiment, and the same parts are denoted by the same reference numerals and detailed description thereof will be omitted. Description is omitted.

In the above-described embodiment, the case where the frame pattern 32 is formed simultaneously with the columnar spacer in the display area and using the same material has been described.
The frame pattern may be formed by overlapping colors or three colors. Further, the columnar spacer is not limited to the colored layer and may be formed of a transparent insulating layer. In this case, the same operation and effect can be obtained.

[0045]

As described above in detail, according to the present invention, a contact hole is provided by providing a columnar spacer for maintaining a gap between an array substrate and a counter substrate on a boundary between adjacent colored layers. And the columnar spacers can be efficiently arranged on the metal wiring, so that an active matrix type liquid crystal display device having a high aperture ratio, excellent display quality, and low brightness and low power consumption can be provided.

[Brief description of the drawings]

FIG. 1 is a perspective view showing an active matrix type liquid crystal display device according to an embodiment of the present invention.

FIG. 2 is an enlarged plan view showing a part of an array substrate of the liquid crystal display device.

FIG. 3 is a sectional view taken along the line ABCDEF of FIG. 1;

FIG. 4 is a plan view schematically showing a colored layer, a scanning line, an auxiliary capacitance wiring, a contact hole, and a columnar spacer of an array substrate of a liquid crystal display device according to a second embodiment of the present invention.

FIG. 5 is a plan view schematically showing a coloring layer, a scanning line, an auxiliary capacitance wiring, a contact hole, and a columnar spacer of an array substrate of a liquid crystal display device according to a third embodiment of the present invention.

FIG. 6 is a plan view schematically showing a colored layer, a scanning line, an auxiliary capacitance line, a contact hole, and a columnar spacer of an array substrate of a liquid crystal display device according to a third embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 ... Liquid crystal display device 12 ... Array substrate 20 ... Counter substrate 25R, 25G, 25B ... Coloring layer 28 ... Pixel TFT 30, 31 ... Circuit TFT 32 ... Frame pattern 36 ... Column spacer 40 ... Display area 50 ... Signal line 51 ... Pixel Electrode 52: auxiliary capacitance line 75: interlayer insulating film 78: upper electrode of auxiliary capacitance line 81a, 81b, 81c: contact hole 90: liquid crystal layer

 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor Masashi Goto 1-9-2 Hara-cho, Fukaya-shi, Saitama F-term in the Toshiba Fukaya Plant (reference) 2H089 LA09 LA16 NA05 NA12 QA11 TA09 TA12 2H092 JA46 JB32 JB64 NA07 PA03 PA08 5C094 AA08 AA10 AA22 AA36 AA43 AA48 BA03 BA43 CA19 CA24 DA13 DB01 DB04 DB10 EA04 EA05 EA10 EB02 EC03 ED03 FA01 FB12 FB15

Claims (6)

[Claims] A plurality of scanning lines provided on an insulating substrate; a plurality of signal lines provided intersecting the scanning lines;
A switching element provided near each intersection of the scanning line and the signal line; a plurality of auxiliary capacitance lines provided to intersect the signal line; a scanning line, a signal line, an auxiliary capacitance wiring, and a switching device. A plurality of striped colored layers covering the element, a plurality of pixel electrodes connected to the switching elements and formed on the colored layer, and a plurality of columnar spacers arranged on the colored layer An array substrate comprising: a counter substrate disposed so as to face the array substrate with a predetermined gap by the columnar spacer; and a liquid crystal layer sealed in a gap between the array substrate and the counter substrate. Wherein each of the columnar spacers is provided so as to overlap a boundary between two adjacent colored layers. 2. Each of the coloring layers has a contact hole for connecting each of the pixel electrodes and a switching element, and each of the columnar spacers is provided in two adjacent coloring layers and is adjacent to each other. 2. The liquid crystal display device according to claim 1, wherein the liquid crystal display device is provided between two combined contact holes. 3. The liquid crystal display device according to claim 2, wherein the contact holes of each of the coloring layers and the columnar spacers are arranged on the auxiliary capacitance wiring. 4. The liquid crystal display device according to claim 1, wherein each of the columnar spacers is provided at an intersection of the auxiliary capacitance line and the signal line. 5. Each of the contact holes has a cross-sectional shape in which a diameter of the colored layer along a longitudinal direction is larger than a diameter of the colored layer along a width direction. The liquid crystal display device according to any one of claims 1 to 4. 6. Each of the columnar spacers has a cross-sectional shape in which the diameter of the colored layer along the longitudinal direction is larger than the diameter of the colored layer along the width direction. 6. The liquid crystal display device according to any one of 1 to 5.