JP2001255555A - Liquid crystal display device and array substrate - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a liquid crystal display device and an array substrate which can dissolve the occurrence of residue of a contact hole, reduce display unevenness and improve productivity. SOLUTION: The array substrate has a switching element, a insulating layer formed on the switching element and a pixel electrode formed on the insulating layer, in the shape of an array. The contact hole for electrically connecting the terminal of the switching element with the pixel electrode is formed on the insulating layer. A corresponding position with the contact hole of the pixel electrode is located from the center of the pixel electrode in a corner, the pixel electrode is disposed in the direction, in which the corresponding position with the contact hole faces the center side of the array in the two sides or the four sides of the array directed opposite to each other.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a liquid crystal display device and an array substrate, and more particularly to a liquid crystal display device and an array substrate capable of reducing display unevenness.

[0002]

2. Description of the Related Art In recent years, light-weight, small-sized, and high-definition liquid crystal display devices have been used in the field of information equipment mainly for computers and the field of video equipment mainly for televisions.

The main structure of such a liquid crystal display device which is generally used is a glass substrate having electrodes and a liquid crystal layer sandwiched between the glass substrates.

More specifically, for example, in a color active matrix type liquid crystal display device, a thin film transistor (switching element) using amorphous silicon or polysilicon as a semiconductor layer and a thin film transistor are formed on an array substrate as a first substrate. The connected pixel electrodes are formed in a matrix shape, and the scanning lines and signal lines connected to the pixel electrodes are formed in a vertical and horizontal stripe shape.

On the other hand, on a counter substrate which is a second substrate,
A color filter having three primary color layers and a counter electrode are formed. Further, a spacer (spacer material) for keeping a distance is provided (enclosed) between the two substrates, and an adhesive formed around the substrates except for the liquid crystal encapsulation opening is further provided. It is fixed at.

As another structure, a switching element and a pixel having a vertical structure on an array substrate are used in order to eliminate the need for precision of bonding accuracy between the two substrates and to improve the aperture ratio of the pixel. Some devices form a color filter layer or a transparent insulating film between the electrodes. In such a structure, it is necessary to form a contact hole in the color filter layer in order to electrically connect (contact) the switching element and the pixel electrode.

[0007]

In a liquid crystal display device having a structure in which a contact hole is formed in a color filter layer, uniform formation of the contact hole over the entire display screen poses a problem. If formed uniformly, the electrical contact between the switching element and the pixel electrode will be good in any pixel, but if it is not uniform, a pixel whose electrical contact will be poor will be formed, and the display will take place in that part. Is uneven.

More specifically, for example, as shown in FIG. 5, a switching element 12 is formed on a substrate 11, a resin 13 to be a color filter is applied thereon, and the switching element 12 is formed by patterning and developing with a photomask. The contact holes 14 are selectively removed. At this time, debris of resin 13 and the like (residue 1
If 5) remains, the electrical contact between the pixel electrode 16 to be formed later and the switching element 12 becomes poor, and the pixel electrode 16 does not function as a display pixel.

[0009] In particular, such non-uniformity is likely to occur in a display area of a display device and near a non-display area.
This is because, in the process of forming the color filter layer, the pattern formed on the substrate on which the display region and the non-display region are to be formed is different between the display region and the non-display region. This is because the film thickness at the time of application of the resin material is thicker in the above-described portion near the non-display region than in other portions.

In other words, when the resin is applied over the entire surface with a spinner, the coating thickness is determined while being influenced by a certain pattern having irregularities, but the thickness differs when the certain pattern breaks down. That's what it means.

When the thickness is thicker than other portions, in forming a contact hole by patterning and development using a photomask, the resin is removed in a development step based on a portion having a normal thickness, so that the thicker resin layer tends to remain as a residue because of the thicker resin layer. Become. For example, a film thickness difference of about 1 μm may occur, and a residue close to this may be generated.

For this reason, in the display area of the display device, which is close to the non-display area, there is a case where a poor electrical contact between the switching element and the pixel electrode occurs. Therefore,
Depending on the degree of occurrence, the yield of products is affected and productivity is impaired.

The present invention has been made in consideration of the above-described problems, and provides a liquid crystal display device and an array substrate which can eliminate display residue and reduce display unevenness and improve productivity by eliminating contact holes. The purpose is to do.

[0014]

In order to solve the above-mentioned problems, a liquid crystal display device according to the present invention comprises an array substrate, an opposing substrate arranged opposite to the array substrate, an array substrate and the opposing substrate. A liquid crystal interposed therebetween, wherein the array substrate has a switching element, an insulating layer formed on the switching element, and pixel electrodes formed on the insulating layer in an array. In the insulating layer, a contact hole for electrically connecting the switching element and the pixel electrode is formed, and a position corresponding to the contact hole of the pixel electrode is located at a corner from a center of the pixel electrode. The contact holes corresponding to the pixel electrodes arranged on at least two opposing sides of the outermost periphery of the pixel electrodes formed in the array, the center of each corresponding pixel electrode; Ri and wherein, characterized in that arranged on the center side of the array substrate.

As a result, at least at two opposing sides of the array, a certain distance from the non-display area where no pixel is required to the contact hole is secured.

Therefore, it is possible to form the contact hole avoiding the thicker portion of the color filter, and the generation of the residue of the contact hole is eliminated. Therefore, the electrical contact between the switching element and the pixel electrode is ensured even in a portion near the non-display region, and the occurrence of display unevenness is reduced.

Further, a liquid crystal display device according to the present invention has an array substrate, a counter substrate disposed to face the array substrate, and a liquid crystal sandwiched between the array substrate and the counter substrate, The array substrate includes a switching element, an insulating layer formed on the switching element, and a pixel electrode formed on the insulating layer in an array.
In the insulating layer, a contact hole for electrically connecting the switching element and the pixel electrode is formed, and a position corresponding to the contact hole of the pixel electrode is at a corner from a center of the pixel electrode, The contact holes corresponding to the pixel electrodes arranged on the outermost periphery among the pixel electrodes formed in the array are arranged closer to the center of the array substrate than the center of each corresponding pixel electrode. And

As a result, the distance from the non-display area where no pixel is required to the contact hole is secured to some extent on the four sides of the array.

Therefore, the contact hole can be formed not only in the upper and lower portions but also in the left and right portions while avoiding the thicker portion of the color filter film, and the generation of the residue in the contact hole can be eliminated. Therefore, the electrical contact between the switching element and the pixel electrode is ensured even in a portion near the non-display region, and the occurrence of display unevenness is reduced.

[0020]

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

FIG. 1 is a diagram showing the arrangement of pixel electrodes and the positions of their respective contact holes in the liquid crystal display device according to the first embodiment of the present invention. As shown in FIG. 1, a pixel electrode 1 is formed on a contact hole 2 formed in each pixel. The arrangement pitch of the pixel electrodes 1 can be, for example, about 100 μm in length and about 30 μm in width.

In this embodiment, the pixels in which the contact holes 2 are arranged above the pixel electrodes 1 in FIG. 1 are arranged in a matrix (array), and the pixel electrodes in the first row in FIG. Only 1 is arranged in a direction rotated by 180 degrees (FIG. 1). As a result, both the pixels in the first row and the pixels in the last row secure a certain distance from the non-display area where no pixel is required to the contact hole.

Therefore, it is possible to form the contact hole avoiding the thicker portion of the color filter film, and the residue of the contact hole is eliminated. Therefore, the electrical contact between the switching element and the pixel electrode is ensured even in a portion near the non-display region, and the occurrence of display unevenness is reduced.

The following is an example of a manufacturing process for confirming this.

For this purpose, a process of forming a thin film transistor element or the like by repeating film formation and patterning can be used in the same manner as a general process of forming an active matrix element.

First, a gate line is formed on a transparent substrate by sputtering with a film thickness of about 0.3 μm using molybdenum, and a pattern is formed in a predetermined shape by photolithography. A gate insulating film layer made of silicon dioxide or silicon nitride having a thickness of 0.15 μm is formed thereon, and a semiconductor layer of a thin film transistor is provided thereon. Further thereon, a 0.3 μm thick ITO (indium tin)
A signal line made of oxide (indium tin oxide) and a source electrode are formed to form a thin film transistor. At this time, these patterns are formed in accordance with the positions of the contact holes as shown in FIG.

Subsequently, a photosensitive resist CR-2000 (manufactured by Fuji Hunt Electronics Technology Co., Ltd.) in which a red pigment was dispersed was applied on the entire surface with a spinner, and
After drying at 0 ° C. for 10 minutes, only the portion where the red colored layer is to be formed is irradiated with ultraviolet rays. 200m exposure
Exposure is performed so as to be J / cm2. Then, development is performed for 20 seconds with a 1 wt% aqueous solution of potassium hydroxide,
By firing at 60 ° C. for 60 minutes, a red colored layer (red color filter) is formed. The pattern of the photomask is such that the contact holes are arranged as shown in FIG.

Similarly, by repeatedly forming green and blue colored layers (color filters), a color filter layer in which the thickness of each colored layer is 1.5 μm is obtained. Here, CG-2000 (manufactured by Fuji Hunt Electronics Technology Co., Ltd.) is used for the green coloring material, and C is used for the blue coloring material.
B-2000 (same as above) can be used.

Thereafter, ITO is sputtered to a thickness of about 0.1 μm to form a pixel electrode, and a pattern is formed in a predetermined shape by photolithography so as to be connected to a source electrode terminal of the thin film transistor through a contact hole. The pattern formation of the pixel electrode has a shape in which only the first row is inverted by 180 degrees as shown in FIG.

Further, a photosensitive black resin is applied with a spinner, dried at 90 ° C. for 10 minutes, and then a spacer portion (7 μm
.Times.15 .mu.m) and an exposure amount of 3
Exposure is performed at 00 mJ / cm2. Then pH = 11.
By developing with an alkaline aqueous solution of No. 5 and baking at 200 ° C. for 60 minutes, a spacer and a light-shielding layer on the outer peripheral portion of the display area are formed.

An array substrate obtained by such a process and an opposite substrate on which a common electrode is formed are coated with an alignment film material AL-1051 (manufactured by Nippon Synthetic Rubber Co., Ltd.) to form an alignment film. A rubbing treatment is performed, and the liquid crystal ZLI-47 is bonded by using an adhesive XN-215 (manufactured by Mitsui Synthetic Rubber Co., Ltd.) made of an epoxy thermosetting resin.
92 (manufactured by E. Merck), and the inlet is sealed with an ultraviolet curable resin to form a liquid crystal cell.

On both sides of this liquid crystal cell, LLC is used as a deflecting plate.
2-9218S (manufactured by Sanritz Co., Ltd.) can be attached and assembled into a module, which can be used for assembling a liquid crystal display device.

If the module thus obtained is driven for image display, a high-quality image can be obtained without any bright spot failure due to contact failure (inability to control the brightness by a signal) or display unevenness.

A contact hole adjacent to the non-display area of the array substrate is formed by an AFM (atomic f
orce microscope) and SEM (sc
annealing electron microscoping
By observing in e), it can be actually confirmed that there is no residue in the contact hole. Further, it can be confirmed that there is no residue in the contact hole by IR (infrared) spectrum and SIMS.

Next, a second embodiment of the present invention will be described with reference to FIG.

FIG. 9 is a diagram showing the arrangement of pixel electrodes and the positions of their respective contact holes in a liquid crystal display device according to a second embodiment of the present invention. As shown in FIG. 1, a pixel electrode 1 is formed on a contact hole 2 formed in each pixel.

In this embodiment, each two adjacent rows of pixels are 1
A matrix is formed as a set in directions different from each other by 80 degrees. In this case, the contact holes of each pixel are arranged so as to be arranged inside two rows (FIG. 2). As a result, both the pixels in the first row and the pixels in the last row secure a certain distance from the non-display area where no display pixel is required to the contact hole.

Therefore, it is possible to form the contact hole avoiding the thicker portion of the color filter film, and the generation of the residue in the contact hole is eliminated. Therefore, the electrical contact between the switching element and the pixel electrode is ensured even in a portion near the non-display region, and the occurrence of display unevenness is reduced.

This embodiment can also be manufactured by the same steps as in the above embodiment. One of the differences in that case is that the contact holes 2 are formed in a photomask at the time of forming the color filter layer in an arrangement as shown in FIG.

If the module thus obtained is actually driven for image display, a high-quality image can be obtained without any bright spot failure or display unevenness due to contact failure.

In this embodiment, as compared with the first embodiment, the arrangement pattern of the pixels is uniform over the entire display, and the occurrence of local defects due to irregularities in the arrangement pattern is further suppressed. I can do it.

That is, according to the present embodiment, since the pixel-shaped formation pattern can be regularized over the entire display section, defects due to local pattern irregularities can be reduced.

Next, a third embodiment of the present invention will be described with reference to FIG.

FIG. 11 is a diagram showing the arrangement of pixel electrodes and the positions of their respective contact holes in a liquid crystal display device according to a third embodiment of the present invention. As shown in FIG. 1, a pixel electrode 1 is formed on a contact hole 2 formed in each pixel.

In this embodiment, the pixels in which the contact holes are arranged on the lower right side of the pixel electrodes in the same figure are arranged in a matrix, and only the last row in the figure has the pixel electrode shape parallel to the rows. In this case, the pixel electrodes are arranged symmetrically with respect to a line parallel to the column only in the last column (FIG. 3). Thus, the distance from the non-display area, which does not require display pixels, to the contact hole is secured to some extent in both the pixels in the first row and the pixels in the last row. Thus, the distance from the non-display area, which does not need to be, to the contact hole is secured to some extent.

Therefore, the contact hole can be formed not only in the upper and lower portions but also in the left and right portions so as to avoid the thicker portion of the color filter film, and the generation of the residue in the contact hole can be eliminated. Therefore, the electrical contact between the switching element and the pixel electrode is ensured even in a portion near the non-display region, and the occurrence of display unevenness is reduced.

This embodiment can be manufactured by the same steps as in the first embodiment. One of the differences is that the contact holes 2 are formed in a photomask at the time of forming the color filter layer in the arrangement shown in FIG.

If the module thus obtained is actually driven for image display, a high-quality image can be obtained without any bright spot failure or display unevenness due to contact failure.

That is, according to the present embodiment, the pixel electrodes are arranged on the four sides of the array so that the positions corresponding to the contact holes are directed toward the center of the array. A certain distance to the hole is ensured, and it is possible to form the contact hole not only in the upper and lower portions but also in the left and right portions while avoiding the thick portion of the color filter film thickness, thereby eliminating the residue of the contact hole. Therefore, the electrical contact between the switching element and the pixel electrode is ensured even in a portion near the non-display region, and the occurrence of display unevenness is reduced.

Next, a fourth embodiment of the present invention will be described with reference to FIG.

FIG. 11 is a diagram showing the arrangement of pixel electrodes and the positions of their respective contact holes in a liquid crystal display device according to a fourth embodiment of the present invention. As shown in FIG. 1, a pixel electrode 1 is formed on a contact hole 2 formed in each pixel.

In this embodiment, a set of four pixels in which contact holes are arranged in one corner direction of a pixel electrode are arranged in a matrix, and each set is formed of a contact hole. The corner where is located
The pixel electrodes are symmetrically formed and arranged so as to be close to the center of each pixel (FIG. 4). This ensures a certain distance from the non-display area where no pixels are required for the pixels in the first row and the pixels in the last row to the contact hole, and the necessity for both the pixels in the first column and the pixels in the last column. Thus, a certain distance from the non-display area to the contact hole is secured.

Therefore, it is possible to form the contact hole not only in the upper and lower portions but also in the left and right portions while avoiding the thick portion of the color filter film, thereby eliminating the residue of the contact hole. Therefore, the electrical contact between the switching element and the pixel electrode is ensured even in a portion near the non-display region, and the occurrence of display unevenness is reduced.

This embodiment can be manufactured by the same steps as in the first embodiment. One of the differences in that case is that the contact holes 2 are formed in a photomask at the time of forming the color filter layer in an arrangement as shown in FIG.

If the module thus obtained is actually driven for image display, a high-quality image can be obtained without any bright spot failure or display unevenness due to contact failure.

That is, according to the present embodiment, the pixel electrodes are arranged on the four sides of the array so that the positions corresponding to the contact holes are directed toward the center of the array. A certain distance to the hole is ensured, and it is possible to form the contact hole not only in the upper and lower portions but also in the left and right portions while avoiding the thick portion of the color filter film thickness, thereby eliminating the residue of the contact hole. Therefore, the electrical contact between the switching element and the pixel electrode is ensured even in a portion near the non-display region, and the occurrence of display unevenness is reduced.

Further, in this embodiment, as compared with the first and third embodiments, the arrangement pattern of pixels is uniform over the entire display, and the occurrence of local defects due to irregularities in the arrangement pattern. Can be further suppressed.

That is, according to the present embodiment, the formation pattern of the pixel shape can be regularized over the entire display section, so that defects due to local irregularity of the pattern can be reduced.

[0059]

As described in detail above, according to the present invention,
Since the pixel electrodes are arranged at least on two opposing sides of the array so that the positions corresponding to the contact holes face the center of the array, a certain distance from the non-display area where no pixels are required to the contact holes is secured. ,
The contact hole can be formed avoiding the thicker portion of the color filter film, and the generation of the contact hole residue can be eliminated. Therefore, the electrical contact between the switching element and the pixel electrode is ensured even in a portion near the non-display region, and the occurrence of display unevenness is reduced.

[Brief description of the drawings]

FIG. 1 is a diagram showing an arrangement of pixel electrodes and a position of each contact hole in a liquid crystal display device or an array substrate according to a first embodiment of the present invention.

FIG. 2 is a diagram showing an arrangement of pixel electrodes on a liquid crystal display device or an array substrate according to a second embodiment of the present invention and positions of respective contact holes thereof.

FIG. 3 is a diagram showing an arrangement of pixel electrodes on a liquid crystal display device or an array substrate according to a third embodiment of the present invention and positions of respective contact holes thereof.

FIG. 4 is a view showing an arrangement of pixel electrodes on a liquid crystal display device or an array substrate according to a fourth embodiment of the present invention and positions of respective contact holes thereof.

FIG. 5 is a diagram illustrating residues generated in a contact hole.

[Explanation of symbols]

 1 pixel electrode 2 contact hole

Continued on front page F-term (reference) 2H092 JA26 JA28 JA35 JA38 JA39 JA42 JA43 JA44 JA46 JB13 JB23 JB32 JB33 JB38 JB52 KA12 KA16 KA18 KB14 KB23 MA05 MA08 MA14 MA15 MA16 MA18 MA19 MA20 MA35 MA37 MA41 NA01 NA09 NA09 A09 PA08 PA09 AA42 AA43 AA48 AA55 BA03 BA43 CA19 CA20 CA24 DA13 DB04 EA04 EA05 EB02 ED03 FA01 FB01 FB02 FB12 FB15 GB10 5G435 AA04 AA17 BB12 CC09 GG12 KK05

Claims (10)

[Claims] 1. An array substrate, comprising: a counter substrate disposed to face the array substrate; and a liquid crystal sandwiched between the array substrate and the counter substrate. An insulating layer formed on the switching element and pixel electrodes formed on the insulating layer are arranged in an array, and the insulating layer electrically connects the switching element and the pixel electrode. And a corresponding position of the pixel electrode with the contact hole is located at a corner from the center of the pixel electrode, and at least two opposing sides of the outermost periphery of the arrayed pixel electrodes. The liquid crystal display, wherein the contact holes corresponding to the arranged pixel electrodes are arranged closer to the center of the array substrate than the center of each corresponding pixel electrode. Location. 2. An array substrate, comprising: a counter substrate disposed to face the array substrate; and a liquid crystal sandwiched between the array substrate and the counter substrate; wherein the array substrate includes a switching element; An insulating layer formed on the switching element and pixel electrodes formed on the insulating layer are arranged in an array, and the insulating layer electrically connects the switching element and the pixel electrode. A position corresponding to the contact hole of the pixel electrode is located at a corner from the center of the pixel electrode, and a pixel electrode arranged at the outermost periphery among the pixel electrodes formed in an array is formed. The liquid crystal display device according to claim 1, wherein the corresponding contact holes are arranged closer to the center of the array substrate than the center of each corresponding pixel electrode. 3. The liquid crystal display device according to claim 1, wherein the pixel electrodes are arranged so that the directions thereof are inverted by 180 degrees for each adjacent column or row of the array. Liquid crystal display. 4. The liquid crystal display device according to claim 2, wherein the pixel electrodes arranged on one side of the outermost periphery are arranged in columns or rows of the array with respect to the shape of the pixel electrode formed on the side adjacent to the one side of the outermost periphery. 3. The liquid crystal display device according to claim 2, wherein the liquid crystal display device has a line-symmetric shape with respect to the rows. 5. The liquid crystal display device according to claim 2, wherein the pixel electrodes are arranged so as to have a line-symmetric shape with respect to the column and the row for each pixel in each column and each row. The liquid crystal display device according to claim 2. 6. An array comprising a switching element, an insulating layer formed on the switching element, and a pixel electrode formed on the insulating layer, wherein the insulating layer includes the switching element and the A contact hole for electrically connecting the pixel electrode to the pixel electrode; a position corresponding to the contact hole of the pixel electrode is located at a corner from a center of the pixel electrode; and among the pixel electrodes formed in the array, The array substrate, wherein the contact holes corresponding to the pixel electrodes arranged on at least two opposing sides of the outermost periphery are arranged closer to the center of the array substrate than the center of each corresponding pixel electrode. 7. An array comprising a switching element, an insulating layer formed on the switching element, and a pixel electrode formed on the insulating layer, wherein the insulating layer includes the switching element and the A contact hole for electrically connecting the pixel electrode to the pixel electrode; a position corresponding to the contact hole of the pixel electrode is located at a corner from a center of the pixel electrode; and among the pixel electrodes formed in the array, The array substrate, wherein the contact holes corresponding to the pixel electrodes arranged at the outermost periphery are arranged closer to the center of the array substrate than the center of each corresponding pixel electrode. 8. The liquid crystal display device according to claim 6, wherein the pixel electrodes are arranged so that the directions thereof are inverted by 180 degrees for each adjacent column or row of the array. Array substrate. 9. The liquid crystal display device according to claim 7, wherein the pixel electrodes arranged on one side of the outermost periphery are arranged in columns or rows of the array with respect to the shape of the pixel electrode formed on the side adjacent to the one side of the outermost periphery. The array substrate according to claim 7, wherein the array substrate has a line-symmetrical shape with respect to a row. 10. The liquid crystal display device according to claim 7, wherein the pixel electrode is arranged in each column and each row in each column.
The array substrate according to claim 7, wherein the array substrate is arranged so as to have a line-symmetric shape with respect to the row.