KR101296631B1 - Liquid Crystal Display Device - Google Patents

Abstract

SUMMARY OF THE INVENTION The present invention provides a liquid crystal display device which prevents afterimage generation during image switching while suppressing a manufacturing cost.

 A liquid crystal display device comprising an array substrate, a color filter substrate, and a liquid crystal layer filled between the substrates and one pixel separated into a plurality of subpixels, wherein the liquid crystal display is formed on a thin film transistor for driving the pixels. A contact hole for electrically connecting a voltage supply electrode and an electrode for applying a voltage to the liquid crystal layer is formed in a connection portion connecting the subpixels.

LCD, Pixel, Subpixel, Thin Film Transistor, Source, Drain

Description

[0001] The present invention relates to a liquid crystal display device,

1 is a cross-sectional view showing the configuration of a conventional liquid crystal display device.

2 is a cross-sectional view showing the configuration of another conventional liquid crystal display device.

3 is a cross-sectional view showing the configuration of a liquid crystal display device according to an embodiment of the present invention.

4 is a plan view showing the configuration of a liquid crystal display device according to an embodiment of the present invention.

5 is a plan view showing a configuration of a modification of the liquid crystal display device according to the embodiment of the present invention.

DESCRIPTION OF THE DRAWINGS FIG.

10: array substrate 11: first substrate

12 gate insulating layer 13 photo acryl layer

14 gate electrode 15 drain electrode

16 source electrode 17 SiN layer

18: reflective electrode 19: ITO transparent electrode

20 contact hole 30 color filter substrate

31: second substrate 33: rivet

34 hole to extract color layer 35 overcoat layer

41: data electrode 43: subpixel

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a liquid crystal display device, and more particularly, to a liquid crystal display device used for a screen of a cellular phone, a display device of a computer, and the like.

Small TFT-LCDs (Thin Film Transistor-Liquid Crystal Displays) have been widely used in mobile phones recently.

Such devices require displays that can be seen in wide viewing angles, moving images, and in direct sunlight due to their use not only indoors, but also outdoors, as well as a digital terrestrial reception environment.

In response to such a demand, semi-transmissive vertical alignment liquid crystal display devices are becoming popular. Representative structures are shown in FIGS. 1 and 2.

1 shows a conventional example in which a transparent resin layer is formed on the color filter substrate side and the cell thickness of the reflective display area is reduced.

BACKGROUND ART A liquid crystal display generally comprises an array substrate in which unit pixels are arranged in a matrix, a color filter substrate formed to face the array substrate and displaying colors, and a liquid crystal layer filled between these two substrates.

The array substrate and the color filter substrate are joined by seal lines at their periphery to form a predetermined cell gap (cell thickness).

The cell gap between these three substrates is kept uniform by spacers or rivets, and the liquid crystal layer is filled therein.

Spacers can be classified into spherical spacers and columnar spacers by the shape thereof. The spherical spacer has a fine spherical shape and is formed on the upper color filter substrate or the lower array substrate by a scattering method, and the columnar spacer is formed of a photosensitive organic film by a photo process.

In FIG. 1, 200 is an array substrate and 201 is a color filter substrate.

In the array substrate 200, the gate electrode 105 is formed on the first substrate 100 made of a transparent insulating material. A plurality of gate electrodes 105 are actually formed in parallel, but only one of them is shown in FIG.

In addition, a gate insulating layer 101 is formed on the first substrate 100 on which the gate electrode 105 is formed to insulate the gate electrode 105, and a gate electrode 105 is disposed on the gate insulating layer 101. A data electrode (not shown) that substantially intersects with is formed.

On the other hand, a plurality of data electrodes are also formed in parallel, and the gate electrode 105 and the data electrode cross each other to define each pixel region.

On the gate insulating layer 101 on which the data electrode is formed, a photoacrylic layer 102 is formed, which is a protective layer for insulating the data electrode and flattening a predetermined step.

The reflective electrode 103 is formed in a region corresponding to the reflective region on the photoacrylic layer 102. An indium tin oxide (ITO) transparent electrode 108 is formed on the photoacryl layer 102 of the transmission region and the reflection electrode 103 of the reflection region.

In addition, an alignment film (not shown) is coated on the ITO transparent electrode 108.

In the array substrate 200, a thin film transistor Tr is formed as a switching element in a region where the gate electrode 105 and the data electrode cross each other.

The thin film transistor Tr includes a gate electrode 105 formed at the lowermost portion, a drain electrode 106 and a source electrode 107 spaced apart from each other formed via a gate insulating film 101 thereon.

In addition, in this specification, what is connected to the data line to the drain electrode 106, the ITO transparent electrode 108, and the reflecting electrode 103 is called the source electrode 107. FIG.

In addition, a contact hole 122 is formed through the photoacrylic layer 102. The contact hole 122 is for connecting the source electrode 107 to the reflective electrode 103 and the ITO transparent electrode 108.

Meanwhile, the color filter substrate 201 includes a second substrate 110 made of a transparent insulating material, and a color filter layer 111 including a black matrix formed on the second substrate 110 and a sub color filter layer separated by the black matrix. ).

In addition, as shown in FIG. 1, a hole 114 for extracting a color layer is formed in a portion of the color filter layer 111, and the first overcoat layer (transparent resin layer) 115 is formed in the hole 114 for extracting the color layer. ) Is buried.

In addition, on the color filter layer 111 and the first overcoat layer 115, a second overcoat layer (transparent resin layer) 112 is formed to form a step of the color filter layer 111.

In addition, the color filter layer 111, the hole 114 for extracting the color layer, the first overcoat layer 115 and the second overcoat layer 112 are formed and then paired with the pixel electrodes formed on the array substrate 200. A common electrode (not shown) for applying an electric field to the liquid crystal layer is formed, and a columnar spacer 104 and a rivet 113 are formed thereon. And an alignment film (not shown) is apply | coated on it.

In the conventional example of FIG. 1, it is necessary to form the thick resin which consists of the 1st overcoat layer 115 and the 2nd overcoat layer 112 on the color filter substrate 201 side.

When forming these overcoat layers 115 and 112, you may apply at the same time using the same material, but in that case, it cannot flatten. Since each of the layers 115 and 112 needs to be formed separately in order to obtain a flattened overcoat layer, the configuration of FIG. 1 requires two steps for forming the overcoat layer. As a result, there has been a problem of cost up.

FIG. 2 removes the second overcoat layer 112 on the color filter substrate 201 side shown in FIG. 1 from this point of view, and forms the photoacrylic layer 120, which is a transparent resin layer, on the array substrate 200 side. There is also.

As shown in FIG. 2, the photoacrylic layer 120 is formed in the reflection region in which the TFT transistor on the array substrate 200 side is formed.

The SiN layer 121 is formed on the photoacrylic layer 120 in the reflective region and the gate insulating layer 101 in the transparent region.

In addition, a reflective electrode 103 is formed on the SiN layer 121 in the reflective region. An ITO transparent electrode 108 is formed on the reflective electrode 103 in the reflective region and the SiN layer 121 in the transparent region.

An alignment film (not shown) is coated on the ITO transparent electrode 108.

In addition, a contact hole 122 is formed through the photo acrylic layer 120 and the SiN layer 121, and the reflective electrode 103, the ITO transparent electrode 108, and the source electrode (through the contact hole 122). 107 is electrically connected.

On the other hand, a color filter layer 111 is formed on the second substrate 110 on the color filter substrate 201 side.

As shown in FIG. 2, a hole 114 for extracting the color layer is formed in a portion of the color filter layer 111, and the first overcoat layer (transparent resin layer) 115 is formed in the hole 114 for extracting the color layer. ) Is buried.

In addition, a common electrode (not shown) is formed on the color filter layer 111 and the first overcoat layer 115.

And the rivet 113 is formed thereon. An alignment film (not shown) is coated on the color filter layer 111 and the rivet 113.

Other configurations are denoted by the same reference numerals as those in Fig. 1, which are basically the same, and the description thereof is omitted here.

In the conventional example of FIG. 2, the transparent resin layer formed on the color filter substrate 201 may be filled only with a hole 114 for extracting the color layer, so that only the first overcoat layer (transparent resin layer) 115 is formed. do. Thereby, since the process for forming an overcoat layer can be reduced only once, manufacturing cost can be suppressed.

However, in the conventional example shown in Fig. 2, the problem is how to connect the reflective electrode 103 or the ITO transparent electrode 108 and the source electrode 107 extending from the thin film transistor Tr.

In the conventional example shown in FIG. 2, the contact hole 122 is formed in the center of the reflective region where the reflective electrode 103 is formed, and the reflective electrode 103 or the ITO transparent electrode 108 and the source electrode 107 are formed. We are connecting.

In this case, since there is a contact hole 122, columnar spacers (see 104 in Fig. 1) cannot be formed in the reflection region in order to hold the cell gap, so that the columnar spacers are made in addition to the pixel region.

However, since this columnar spacer itself has an orientation regulation capability and performs a different operation from the contact hole 122, the orientation to regulate the orientation is inconsistent with the original liquid crystal orientation.

For this reason, the problem that an afterimage changes simultaneously with the image displayed on a liquid crystal display device tends to arise. For example, when a black rectangle is displayed on white paper and the entire screen is replaced with white, there is a problem that a defect such as a trace of black rectangle is observed for several seconds occurs.

In addition, since the contact hole 122 is formed through the photoacrylic layer 120 and the SiN layer 121, the depth and diameter of the contact hole 122 are increased, which affects the orientation of the liquid crystal molecules.

Disclosure of Invention The present invention has been made in view of the above-mentioned problems, and an object thereof is to provide a liquid crystal display device which prevents afterimage generation during image switching while reducing manufacturing cost.

The present invention is a semi-transmissive liquid crystal display device comprising an array substrate, a color filter substrate, and a liquid crystal layer filled between the substrates, and having a plurality of pixels, wherein each pixel includes a plurality of subpixels. At least one of the subpixels is a reflection region and the other is separated into a transmission region. Each of the subpixels is connected to each other by a connecting portion, a thin film transistor is formed on the reflective region, and the cell thickness of the liquid crystal layer is formed on the thin film transistor side. In order to change, a resin layer for forming a step is formed, the resin layer covers at least a portion of the thin film transistor, and a voltage supply electrode formed in the thin film transistor for driving the pixel and an electrode for applying a voltage to the liquid crystal layer The resin layer of the connection part connecting the subpixels with a contact hole for connecting to Since the liquid crystal display device is formed in the area where the step is not formed, the stepped end portion can prevent generation of afterimages at the time of image switching while suppressing the manufacturing cost.

Hereinafter, exemplary embodiments of a liquid crystal display according to the present invention will be described with reference to the accompanying drawings.

3 and 4 are cross-sectional views and plan views showing the configuration of a liquid crystal display device according to an embodiment of the present invention.

3 and 4 illustrate an A-Si type transflective liquid crystal display as an example. In addition, the resolution of the QVGA, the screen size is 2.4 inches diagonal, vertically aligned liquid crystal display device.

In addition, a negative liquid crystal of dielectric anisotropy is used, and is vertically oriented without voltage application. However, this is one example, and the present invention is not limited to this.

3 and 4, 10 is an array substrate and 30 is a color filter substrate.

In the array substrate 10, the gate electrode 14 is formed on the first substrate 11 made of a transparent insulating material. Although only one is described in FIG. 3, a plurality of gate electrodes 14 are actually formed on the first substrate 11 in parallel.

In addition, a gate insulating layer 12 is formed on the first substrate 11 on which the gate electrode 14 is formed to insulate the gate electrode 14, and the gate electrode 14 is disposed on the gate insulating layer 12. The data electrode 41 substantially intersects with is formed.

In addition, the photoacrylic layer 13 is formed on the thin film transistor Tr side (reflection region) to insulate the data electrode 41 and form a predetermined step on the gate insulating layer 12 on which the data electrode 41 is formed. It is.

Although the thickness of the photoacrylic layer 13 may be set to arbitrary thickness, about 2 micron is suitable.

The thin film transistor Tr is a switching element and is formed in an area where the gate electrode 14 and the data electrode 41 cross each pixel area.

The thin film transistor Tr includes a gate electrode 14 formed at the lowermost portion, a drain electrode 15 and a source electrode (voltage supply electrode) 16 spaced apart from each other formed via a gate insulating film 12 thereon. It is.

The SiN layer 17 is formed on the photoacrylic layer 13 in the reflection region and the gate insulating layer 12 in the transmission region.

In addition, the reflective electrode 18 is formed on the SiN layer 17 in the reflective region, and the ITO transparent electrode (ITO) is applied to apply a voltage to the liquid crystal layer on the reflective electrode 18 of the reflective region and the SiN layer 17 of the transmissive region. 19) is formed. In addition, an alignment film (not shown) is coated on the ITO transparent electrode 19.

In the embodiment of the present invention, a source electrode extension portion 16A extending from the source electrode 16 is formed. In addition, a contact hole 20 is formed through the SiN layer 17 to electrically connect the source electrode extension 16A and the ITO transparent electrode 19.

In the present embodiment, as described above, the ITO transparent electrode 19 is formed on both sides of the reflective region where the photoacrylic layer 13 is formed and the transmissive region where the photoacrylic layer 13 is not formed.

Steps arise naturally at the boundary between the portion where the photoacrylic layer 13 is and the portion that is not.

The contact hole 20 is formed in the transmission region where the photoacrylic layer 13 is not formed and in a portion near the step portion (a position spaced by a small predetermined distance from the step portion).

The predetermined distance from the stepped portion is not particularly limited, but may be appropriately determined. In addition, as shown in FIG. 4, in the case where one pixel is divided into a plurality of subpixels, a contact hole 20 is formed at a connection portion connecting the subpixels to a position where the contact hole 20 is formed. The source electrode 16 is extended by the source electrode extension 16A.

Meanwhile, the color filter substrate 30 includes a second substrate 31 made of a transparent insulating material, and a color filter layer 32 having a black matrix formed on the second substrate 31 and a sub color filter layer separated by the black matrix. ).

As shown in Fig. 3, a portion 34 of the color filter layer 32 is formed with a hole 34 for extracting the color layer, and an overcoat layer (transparent resin layer) 35 is formed in the hole 34 for extracting the color layer. Buried

On the color filter layer 32 and the overcoat layer 35, a common electrode (not shown) is formed in pairs with the pixel electrodes formed on the array substrate 10 to apply an electric field to the liquid crystal layer.

And the rivet 33 for regulating an orientation is formed on it. On the color filter layer 32 and the rivet 33, an alignment film (not shown) for determining the initial alignment direction of the liquid crystal is applied.

The configuration of this embodiment will be described with reference to FIG.

As shown in FIG. 4, on the array substrate 10, a plurality of gate electrodes 14 arranged in parallel and a plurality of data electrodes 41 arranged in parallel while substantially crossing the gate electrodes 14 are formed. It is.

In addition, the pixel electrode is defined by the intersection of the gate electrode 14 and the data electrode 41. 4 shows a pixel area for one unit.

In each pixel area, a thin film transistor Tr is formed as a switching element for driving each pixel. In addition, in each pixel region, an ITO transparent electrode 19 is formed to apply an electric field to the liquid crystal layer.

Here, the ITO transparent electrode 19 may be formed of a transparent conductive material other than ITO.

In the present embodiment, as described above, one pixel is divided into a plurality of subpixels 43, and the connection portion (connection portion) 43A connecting each subpixel 43 is as shown in FIG. The width of the subpixel 43 is smaller than that of the portion of the subpixel 43.

In the present embodiment, as described above, the connection portion 43A connecting between the sub-pixels 43 close to the stepped portion where the ITO transparent electrode 19 is formed in the transmissive region where the photoacrylic layer 13 is not formed. The contact hole 20 for connecting the source electrode 16 and the ITO transparent electrode 19 is formed, and the source electrode 16 is extended by the source electrode extension part 16A to the position there.

In addition, a contact hole 20 is formed in a region where the source electrode extension 16A is formed, and the source electrode 16 and the ITO transparent electrode (eg, through the source electrode extension 16A and the contact hole 20). 19) is electrically connected.

As a layer structure, the source electrode 16 or the source electrode extension part 16A is provided under the SiN layer 17, the contact hole 20 is opened through the SiN layer 17, and this contact hole 20 is carried out. The ITO transparent electrode 19 is formed in the contact hole 20 so as to fill the gap (In FIG. 3, the ITO transparent electrode 19 is not formed in the contact hole 20 for the sake of simplicity of the drawing. It is formed in the shape which entered in (20). The ITO transparent electrode 19 connects the ITO transparent electrodes, which are the subpixels 43, to each other.

Moreover, in order to stabilize the orientation of the subpixel 43, especially the reflection area | region, the rivet 33 for orientation stabilization is arrange | positioned in the center of the subpixel 43 for reflection. For example, one of the rivets 33 may be replaced with a spacer made of a resist or an acrylic resin formed in a columnar shape on the color filter substrate.

That is, this columnar spacer is also arranged in the center of the subpixel 43 of the reflection area. The spacer comes into contact with the surface of the reflective electrode 18, but its inclined surface controls the orientation. This makes it possible to stabilize the orientation with respect to the columnar spacer as well, thereby achieving good display.

As described above, in the present embodiment, the overcoat layer for forming the step is not formed on the color filter substrate 30 side, but is formed on the array substrate 10 side, thereby reducing the manufacturing process and suppressing the manufacturing course.

Further, in order to electrically connect the source electrode 16 and the ITO transparent electrode 19, the contact hole 20 is located between the subpixels 43 in the transmission region, close to the step by the photoacrylic layer 13 of the array substrate. The contact hole 20 is formed only in the SiN layer 17 because the source electrode 16 is extended by the source electrode extension 16A to the position therebetween, and is formed in the connection portion 43A for connecting the The depth and diameter become small, and the influence on the orientation of liquid crystal molecules can be significantly suppressed.

In addition, the portion of the connection portion 43A between the sub-pixels 43 is easy to align the liquid crystal molecules vertically, the contribution to the white luminance is small, and because the original portion was black, the contact hole was formed in the connection portion 43A. In the case of forming (20), even if the opaque region called the source electrode extension portion 16A becomes the connection portion 43A, the decrease in the white luminance can be minimized.

In order to stabilize the orientation of the portion of the connection portion 43A, as shown in FIG. The part 50 may be formed.

The transparent electrode (not shown) on the color filter substrate 30 side has a common voltage, and has the same potential as the common electrode 45 on the array substrate 10 side.

As a result, the liquid crystal molecules are vertically aligned in the connecting portion 43A, so that the alignment with the portions on both sides of the connecting portion 43A can be divided.

In addition, an electric field is generated between the common electrode 45 on the array substrate and the ITO transparent electrode 19. The liquid crystal molecules also have an effect of stabilizing the orientation by this electric field.

In the layer structure, the subpixels are formed into the common electrode 45 and the SiN layer 17 in the gap portion, and in the connection portion 43A, the common electrode 45, the AiN layer 17, and the source electrode 16 are formed. And the contact hole 20 and the ITO transparent electrode 19.

In the above embodiment, the vertical alignment liquid crystal display device is shown, but needless to say that the present invention is also effective in the horizontal alignment, ECB, and IPS types.

The liquid crystal display device according to the present invention as described above can prevent the generation of afterimages during image switching while suppressing the manufacturing cost.

Claims (4)

In the semi-transmissive liquid crystal display device comprising an array substrate, a color filter substrate, and a liquid crystal layer filled between the substrates, and having a plurality of pixels, Each pixel has a plurality of subpixels, at least one of the plurality of subpixels is a reflection area and the remainder is separated into a transmission area, and each subpixel is connected to each other by a connecting portion, A thin film transistor is formed in the reflective region, and a stepped resin layer is formed on the thin film transistor side to change the cell thickness of the liquid crystal layer, and the resin layer covers at least a portion of the thin film transistor. A region in which the resin layer of the connection portion connecting the subpixels is formed in a contact hole for electrically connecting a voltage supply electrode formed in the thin film transistor for driving the pixel and an electrode for applying a voltage to the liquid crystal layer And a stepped end portion. delete The transflective type of claim 1, wherein a reflective electrode is formed on the resin layer to form a reflective display area, and a semi-transmissive protrusion is formed in the center portion of the reflective display area to hold a cell gap. LCD display device. 4. The transflective liquid crystal display device according to claim 1 or 3, wherein a layer of a common potential is formed between both sides of the connection portion connecting the subpixels and the subpixels.

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