JP2001183669A - Liquid crystal display - Google Patents

Abstract

(57) [Problem] To provide a liquid crystal display device provided with a columnar spacer made of resin so that the spacer does not easily collapse even when an external force is applied. SOLUTION: On a top surface of a gate insulating film 7 between a gate line 2 and an auxiliary capacitance line 3, a first step correction layer 3 is provided.
1 is provided, and a second step correction layer 32 is provided on the upper surface of the gate insulating film 7 and the pixel electrode 6 on the side of the gate line 2 opposite to the storage capacitance line 3. This allows
The upper surface of the overcoat film 11 under the spacer 25 becomes substantially flat over a wide range. The first and second step correction layers 31 and 32 are formed at the same time as the formation of the drain line using the same material as the drain line.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

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

[0002]

2. Description of the Related Art FIG. 4 shows a plan view of a part of a lower glass substrate side of an example of a conventional active matrix type liquid crystal display device, and FIG. 5 shows a cross-sectional view corresponding to a portion along the line XX. It is shown. However, FIG. 4 shows a plan view of the lower glass substrate side in which the overcoat film 11 shown in FIG. 5 is omitted. This liquid crystal display device includes a lower glass substrate 1 and an upper glass substrate 21.

On the lower glass substrate 1, a gate line 2 and an auxiliary capacitance line 3 are provided extending in a row direction, and a drain line 4 is provided extending in a column direction. A thin film transistor 5 as a switching element and a pixel electrode 6 are provided near the intersection. In this case, the gate line 2 and the auxiliary capacitance line 3 are provided on the upper surface of the lower glass substrate 1. The drain line 4 and the pixel electrode 6 are provided on the upper surface of the gate insulating film 7 provided on the upper surface of the lower glass substrate 1 including the gate line 2 and the like. Thin film transistor 5
Comprises a gate electrode 8 connected to the gate line 2, a drain electrode 9 connected to the drain line 4, a source electrode 10 connected to the pixel electrode 6, and the like.

As shown in FIG. 4, the auxiliary capacitance line 3 has a substantially U-shaped auxiliary capacitance electrode 3a, and the left and right sides and the upper side of the pixel electrode 6 are superimposed on the auxiliary capacitance electrode 3a. I have. In FIG. 4, an overcoat film 11 is provided in a portion other than a portion surrounded by a two-dot chain line. In FIG. 4, a square region indicated by a dashed line is a region where a prismatic spacer 25 to be described later is disposed, a region corresponding to the center of the lower side of the upper pixel electrode 6, and the lower pixel electrode 6. It consists of a region corresponding to the center of the upper side and a region therebetween.

On the other hand, a black mask 22 is provided at a predetermined position on the lower surface of the upper glass substrate 21, and red, green, and blue color filter elements 23 are provided on the lower surface. Is provided. Counter electrode 2
A rectangular column spacer 25 made of resin is provided on the lower surface of the substrate 4 at a portion corresponding to a square region indicated by a chain line in FIG.

Then, the lower glass substrate 1 and the upper glass substrate 2
1 are bonded to each other via a seal material (not shown) interposed therebetween, and a liquid crystal 26 is sealed between the two glass substrates 1 and 21 inside the seal material. In this state, the lower end surface of the spacer 25 is disposed on the overcoat film 11 in a region indicated by a chain line in FIG.

[0007]

In such a conventional liquid crystal display device, as shown in FIG. 5, there is a large step on the upper surface of the overcoat film 11 under the spacer 25 over a relatively wide range. Poor flatness. That is,
When viewed from the left side in FIG. 5, a region where the gate insulating film 7, the pixel electrode 6 and the overcoat film 11 are provided on the lower glass substrate 1, the gate line 2, the gate insulating film 7 and the There is a region where the coat film 11 is provided, a region where the gate insulating film 7 and the overcoat film 11 are provided, a region where the auxiliary capacitance line 3, the gate insulating film 7, the pixel electrode 6 and the overcoat film 11 are provided, The upper surface of the overcoat film 11 under the spacer 25 has poor flatness. As a result, when an external force is applied, pressure is unevenly applied to the prismatic spacer 25,
The spacer 25 may collapse. When such a phenomenon occurs, the gap becomes non-uniform, and the display quality deteriorates. An object of the present invention is to make a spacer hard to collapse.

[0008]

According to the present invention, a substrate provided with a switching element, a wiring connected to the switching element, and a pixel electrode connected to the switching element is provided. In a liquid crystal display device in which an opposing electrode provided on the other substrate is provided with a spacer interposed therebetween, an insulating film is provided on the wiring on the one substrate, and the wiring on the insulating film is provided on the insulating film. A step correction layer is provided in the vicinity of a corresponding region, and the spacer is provided on the step correction layer. According to this invention, the insulating film is provided on the wiring on one substrate, and the step correction layer is provided near the region corresponding to the wiring on the insulating film. The flatness can be improved, and the spacer can be made less likely to collapse.

[0009]

FIG. 1 is a plan view of a part of an active matrix type liquid crystal display device on a lower glass substrate side according to an embodiment of the present invention, and FIG. FIG. 3 shows a corresponding sectional view. However,
Also in this case, FIG. 1 shows a plan view of the lower glass substrate side with the overcoat film 11 shown in FIG. 2 omitted. In these drawings, the same portions as those in FIGS. 4 and 5 are denoted by the same reference numerals, and description thereof will be omitted as appropriate.

This liquid crystal display device is different from the conventional case shown in FIGS. 4 and 5 in that a first step correction layer 31 is provided on the upper surface of the gate insulating film 7 between the gate line 2 and the auxiliary capacitance line 3. The second step correction layer 32 is provided on the upper surface of the gate insulating film 7 and the pixel electrode 6 on the opposite side of the gate line 2 from the auxiliary capacitance line 3.

In this case, the first and second step correction layers 3
Reference numerals 1 and 32 are formed of the same material as the drain line 4, the drain electrode 9 and the source electrode 10 at the same time as their formation. Therefore, the number of manufacturing steps can be prevented from increasing. Further, in this case, the first step correction layer 31 is connected to the drain electrode 9 and the second step correction layer 32 is connected to the source electrode 10. However, the present invention is not limited to this. For example, as shown in FIG. The first step correction layer 31 may be disconnected from the drain electrode 9, and the second step correction layer 32 may be disconnected from the source electrode 10.

Now, when viewed from the left side in FIG.
Below the spacer 25, the first region where the gate insulating film 7, the pixel electrode 6, the second step correction layer 32 and the overcoat film 11 are provided on the lower glass substrate 1, the gate line 2, the gate insulating film 7 and the overlying region. The second region where the coating film 11 is provided, the gate insulating film 7, the first step correction layer 31, and the third region where the overcoat film 11 is provided, the auxiliary capacitance line 3, the gate insulating film 7, the pixel electrode 6, and the over region. A spacer arrangement surface composed of a fourth region provided with the coat film 11 is formed.

Here, the thicknesses of the gate line 2 and the auxiliary capacitance line 3 are the same as the thicknesses of the drain line 4, the drain electrode 9 and the source electrode 10, that is, the thicknesses of the first and second step correction layers 31 and 32. And Then, the total thickness of the first region and the total thickness of the fourth region are the same, and the total thickness of the second region and the total thickness of the third region are the same. Further, the total thickness of each of the first region and the fourth region is larger than the total thickness of each of the second region and the third region by the thickness of the pixel electrode 6.

Incidentally, the thickness of the pixel electrode 6 is usually 500
If the height of the spacer 25 (corresponding to the gap) is, for example, about 5 μm, which is about 1/100, it can be almost ignored. Therefore, the upper surface of the overcoat film 11 under the spacer 25 can be regarded as substantially flat over a wide range. As a result, when an external force is applied, the pressure is substantially uniformly applied to the prismatic spacers 25, and the spacers 25 can be made hard to collapse, so that the gap can be made uniform and the display quality does not deteriorate. Can be

Incidentally, since the gate line 2 and the like and the drain line 4 and the like are actually formed separately, it is difficult to make the thickness of the gate line 2 and the like equal to the thickness of the drain line 4 and the like. Therefore, when the difference between the thickness of the gate line 2 and the like and the thickness of the drain line 4 and the like is set to be within ± 200 nm, the height of the spacer 25 becomes, for example, 5 mm.
If it is about μm, it will be about 4% or less of the
The upper surface of the lower overcoat film 11 can be made substantially flat over a wide range. When an anodic oxide film is formed on the surface of the gate line 2 or the like, the difference between the total thickness of the gate line 2 or the like and the anodic oxide film and the thickness of the first and second step correction layers 31 and 32 is ± 200 nm. What is necessary is just to be within.

In the above-described embodiment, as shown by a dashed line in FIG. 1, the area where the prismatic spacer 25 is disposed is divided into a region corresponding to the center of the lower side of the upper pixel electrode 6 and the lower pixel electrode 6. Although the description has been given of the case where the region corresponds to the central portion of the upper side portion and the region therebetween, the present invention is not limited thereto, and the region between the lower central portion of the upper pixel electrode 6 and the upper central portion of the lower pixel electrode 6 may be used. Only the area between them may be used. In this case, since the thickness of the pixel electrode 6 is irrelevant, the upper surface of the overcoat film 11 below the spacer 25 can be further flattened. Further, in the above-described embodiment, the case where the cross-sectional shape of the spacer 25 is a square shape is described, but the present invention is not limited to this, and may be a rectangular shape, a circular shape, or the like.

[0017]

As described above, according to the present invention, an insulating film is provided on a wiring on one substrate, and a step correction layer is provided near a region on the insulating film corresponding to the wiring. Therefore, the flatness of the spacer arrangement surface on one of the substrates is improved, so that the spacers can be made less likely to collapse, so that the gap can be made uniform and the display quality can be prevented from deteriorating. .

[Brief description of the drawings]

FIG. 1 is a plan view of a part of a liquid crystal display device on a lower glass substrate side according to an embodiment of the present invention.

FIG. 2 is a sectional view corresponding to a portion along line XX in FIG. 1;

FIG. 3 is a plan view of a part of a lower glass substrate side of a liquid crystal display device according to another embodiment of the present invention.

FIG. 4 is a plan view of a part of a lower glass substrate side of an example of a conventional liquid crystal display device.

FIG. 5 is a sectional view corresponding to a portion along line XX in FIG. 4;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Lower glass substrate 2 Gate line 3 Auxiliary capacitance line 4 Drain line 5 Thin film transistor 6 Pixel electrode 7 Gate insulating film 8 Gate electrode 9 Drain electrode 10 Source electrode 11 Overcoat film 21 Upper glass substrate 24 Counter electrode 25 Spacer 26 Liquid crystal 31 Liquid crystal 31 First Step correction layer 32 Second step correction layer

Claims (11)

[Claims] 1. A substrate provided with a switching element, a wiring connected to the switching element, and a pixel electrode connected to the switching element, and a counter electrode facing the pixel electrode are provided. In a liquid crystal display device in which a spacer is interposed between the other substrate and a spacer, an insulating film is provided on the wiring on the one substrate, and a step is corrected near a region corresponding to the wiring on the insulating film. A liquid crystal display device, wherein a layer is provided and the spacer is provided on the step correction layer. 2. The liquid crystal display device according to claim 1, wherein the wiring is a gate line, and the insulating film is a gate insulating film. 3. The invention according to claim 2, wherein an auxiliary capacitance line is provided below the gate insulating film in parallel with the gate line, and the step correction layer is provided between the gate line and the auxiliary capacitance line. The liquid crystal display device, wherein the spacer is provided at a portion corresponding to the step correction layer and the gate line and the auxiliary capacitance line in the vicinity thereof. 4. The liquid crystal display according to claim 2, wherein the step correction layer is formed of a metal layer formed of the same material as the drain line at the same time as the formation of the drain line. apparatus. 5. The invention according to claim 3, wherein another step correction layer is provided on the one substrate on a side of the gate line opposite to the auxiliary capacitance line, and the spacer is formed of the two step correction layers. And a portion corresponding to the gate line and the auxiliary capacitance line in the vicinity thereof. 6. The invention according to claim 5, wherein the spacer is provided at a portion corresponding to adjacent sides of the two pixel electrodes disposed on both sides of the gate line. Liquid crystal display device. 7. The liquid crystal display according to claim 5, wherein the step correction layer is formed of a metal layer formed of the same material as the drain line at the same time as the formation of the drain line. apparatus. 8. The liquid crystal display device according to claim 4, wherein a difference between a thickness of the gate line and a thickness of the drain line is within ± 200 nm. 9. The method according to claim 4, wherein the difference between the total thickness of the gate line and the anodic oxide film formed on the surface thereof and the thickness of the drain line is ± 2.
A liquid crystal display device having a thickness of not more than 00 nm. 10. The liquid crystal display device according to claim 1, wherein the spacer is formed in a column shape with a resin. 11. The liquid crystal display device according to claim 10, wherein the spacer is formed on the counter electrode of the other substrate.