JPH11295744A - Liquid crystal display device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a liquid crystal display device capable of preventing unevenness of display caused by gap irregularity in the outer circumferential edge part of a display area and also preventing the leakage of light from the neighborhood of the outer circumferential edge of the display area. SOLUTION: A lattices 1st light shielding film 22A is provided in a display are A on an undersurface of an upside substrate 21, an almost framed 2nd light shielding film 22B is provided on in a non-display are B on the undersurface of the upside substrate 21, the outer circumferential edge of this 2nd shading film 22B is extended up to the end face of the upside substrate 21, and a sealing materials 27 is formed in the area where the 2nd light shielding film 22B is arranged. Therefore, even if the non-display area B is reduced in size smaller than the case in which the sealing material 27 outside of the 2nd light shielding film 22B, it is possible to prevent unevenness of display in the circumferential edge part of the display area and also prevent leakage of light from the neighborhood of the outer circumferential edge of the display area.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a liquid crystal display device in which light leakage from the vicinity of the outer periphery of a display area and display unevenness due to gap unevenness at the outer periphery of the display area are prevented.

[0002]

2. Description of the Related Art FIG. 5A is a partial sectional view of an example of a conventional liquid crystal display device, and FIG. 5B is a partial bottom view of an upper substrate thereof. In this case, FIG.
FIG. 6 is a cross-sectional view corresponding to a portion along line XX in FIG. In this liquid crystal display device, a liquid crystal display panel 3 is housed between a lower case 1 and an upper case 2. The lower case 1 basically has a structure in which side walls 1b are provided on four sides of a rectangular frame-shaped lower plate 1a having a rectangular opening 4. The upper case 2 basically has side walls 2 on four sides of a rectangular frame-shaped upper plate 2 a having a rectangular display window 5.
b is provided. When the liquid crystal display panel 3 is stored in the lower case 1, the four side walls 1 b of the lower case 1 are connected to the four side walls 2 b of the upper case 2.
And are connected to each other by hooks (not shown).

[0005] The liquid crystal display panel 3 includes a lower substrate 11 and an upper substrate 21. The upper surface of the lower substrate 11 has an IT
A pixel electrode 12 made of O and a thin film transistor 13 as a switching element are provided in a matrix. An overcoat film 14 is provided on the upper surfaces of the pixel electrode 12, the thin film transistor 13, and the lower substrate 11, and an alignment film 15 is provided on a predetermined portion of the upper surface. In this case, a region where the pixel electrode 12 and the thin film transistor 13 are provided is a display region A, and a region outside the display region A is a non-display region B. The opening edge of the display window 5 of the upper case 2 is located outside the outer peripheral edge of the display area A (the right side in FIG. 5A). A first light-shielding film 22A made of chrome or the like is provided in a lattice shape in a display area A on the lower surface of the upper substrate 21, and a second light-shielding film made of the same material is provided on an inner peripheral portion of the non-display area B on the lower surface. 22B is provided in a frame shape. In this case, the first
An opening 22a is formed in a portion of the light shielding film 22A corresponding to the pixel electrode 12. Also, the second light shielding film 22B
Is located at the outer peripheral edge of the display area A, that is, located inside (to the left in FIG. 5A) the position corresponding to the opening edge of the display window 5 of the upper case 2, The outer peripheral portion is located outside (to the right in FIG. 5A) a position corresponding to the opening edge of the display window 5. In addition,
In FIG. 5B, the portions of the first light-shielding film 22A and the second light-shielding film 22B are cross-hatched (hatched). Red, green, and blue color filter elements 23 are provided on the lower surface of the first light-shielding film 22A and the like in the display area A. Color filter element 23, second light shielding film 2
2B and an overcoat film 24 on the lower surface of the upper substrate 21.
And a common electrode 25 made of ITO is provided on the lower surface thereof.
Is provided, and an alignment film 26 is provided at a predetermined location on the lower surface. In this case, the outer peripheral edge of the alignment film 26 is the second
The position corresponds to the outer peripheral edge of the light-shielding film 22 </ b> B, and also corresponds to the outer peripheral edge of the alignment film 15 of the lower substrate 11. Then, the lower substrate 11 and the upper substrate 21
Are bonded to each other via a substantially frame-shaped sealing material 27, and a liquid crystal 28 is sealed between the alignment films 15 and 26 of the substrates 11 and 21 inside the sealing material 27. In this case, the sealing material 27 is located outside the second light shielding film 22B (FIG. 5).
(A) is provided on the right side.

Next, a non-display area B on the lower surface of the upper substrate 21
The reason why the second light shielding film 22B is provided will now be described.
First, there is some backlash between the liquid crystal display panel 3 and the lower case 1, and there is some backlash between both cases 1 and 2. For this reason, it is extremely difficult to always align the opening edge of the display window 5 of the upper case 2 exactly with the boundary between the display area A and the non-display area B. Therefore, it is conceivable that the opening edge of the display window 5 of the upper case 2 is positioned inside the outer peripheral edge of the display area A in consideration of the above-mentioned play. However, in such a case, the upper case 2 covers the outer peripheral edge of the display area A, which is not preferable. Therefore, as described above, the opening edge of the display window 5 of the upper case 2 is located outside the outer peripheral edge of the display area A. However, if this is simply done, the inner peripheral portion of the non-display region B outside the display region A is exposed without being covered by the upper case 2, and light is emitted from the exposed inner peripheral portion of the non-display region B. It will leak. Therefore, as described above, the second light shielding film 22B is provided on the inner peripheral portion of the non-display area B on the lower surface of the upper substrate 21 in order to secure a light shielding area margin. That is, the inner peripheral edge of the second light shielding film 22B is located at the outer peripheral edge of the display area A, and the outer peripheral edge of the second light shielding film 22B is positioned at the display window 5 of the upper case 2.
Are located outside the opening edge of the opening. Thus, even if the above-mentioned rattling occurs, the outer peripheral edge of the display area A is not covered by the second light-shielding film 22B as well as the upper case 2, and the inner peripheral part of the non-display area B is not covered. From the light.

[0005]

However, the light-shielding area margin area described above is an intermediate gap between the gap of the display area and the gap of the seal area. The gap cannot be kept constant by the spacer, and the instability of the gap in this area affects the gap at the outer peripheral edge of the display area, causing display unevenness at the outer peripheral edge of the display area. On the other hand, in recent years, in order to respond to the demand for miniaturization of the liquid crystal display device, technological innovation has been progressing toward a non-display region on the outer periphery of the display region, that is, a reduction in the frame portion. In this case, the distance between the display region and the seal region has been increased. And the gap at this portion is less unstable, so that the gap at the outer peripheral edge of the display area is less likely to be unstable. In this case, a sufficient light-shielding area margin cannot be obtained, which causes light leakage. SUMMARY OF THE INVENTION It is an object of the present invention to provide a liquid crystal display device capable of preventing display unevenness due to gap unevenness at a display area outer peripheral edge and light leakage from the vicinity of the display area outer peripheral edge.

[0006]

According to the present invention, in order to solve the above-mentioned problems, two substrates are bonded together via a substantially frame-shaped sealing material, and a liquid crystal is provided between the two substrates inside the sealing material. In a liquid crystal display device that performs display by driving liquid crystal in a display area including a plurality of pixels, an outer peripheral portion of the display area on a surface of one of the two substrates facing the other substrate , A light-shielding film is provided at least in a region extending to the outside of the sealing material.
According to the present invention, since the light-shielding film provided along the outer periphery of the display area is formed to extend to the outside of the sealing material,
Even when the non-display area outside the display area, that is, the frame is narrowed, it is possible to reliably prevent light leakage from the vicinity of the outer periphery of the display area, and a dummy seal inside the seal material is made of the same material mixed with the same spacer. A liquid crystal display device that can be formed in the same process and that can prevent display unevenness due to gap unevenness at the outer peripheral edge of the display region can be easily manufactured.

[0007]

FIG. 1A is a sectional view of a main part of a liquid crystal display device according to a first embodiment of the present invention.
(B) shows a partial bottom view of the upper substrate. In this case, FIG. 1A is a cross-sectional view corresponding to a portion along line XX in FIG. 1B. In these figures,
5A and 5B are denoted by the same reference numerals, and description thereof will be omitted as appropriate. In FIG. 1B, the portions of the first light-shielding film 22A and the second light-shielding film 22B are cross-hatched (hatched). This liquid crystal display device is different from the liquid crystal display device shown in FIGS. 5A and 5B in that the outer peripheral edge of the second light-shielding film 22B is provided up to the end of the upper substrate 21. The point is that the sealing material 27 is formed on the light shielding film 22B.
In this embodiment, the outer peripheral portions of the alignment films 15 and 26 are located outside the display area A and inside the sealing material 27.

Thus, in this liquid crystal display device, the second
From the outer peripheral portion of the display area A to the upper substrate 2.
1 and the sealing material 27 is provided on the second light-shielding film 22B, so that the second light-shielding film 22B is formed as in the related art shown in FIGS. 5A and 5B. The non-display area B can be reduced as compared with the case where the sealing material 27 is provided outside the liquid crystal display panel, and the frame of the liquid crystal display panel 3 can be narrowed, and there is no display unevenness due to light leakage or gap failure. A liquid crystal display device is obtained.

FIG. 2A is a sectional view of a main part of a liquid crystal display device according to a second embodiment of the present invention, and FIG. 2B is a bottom view of a part of the upper substrate. . In this case, FIG. 2A is a cross-sectional view corresponding to a portion along line XX in FIG. 2B. In these figures, FIG.
(A) and (B) are given the same reference numerals and the description thereof will be omitted as appropriate. In FIG. 2B, the first light-shielding film 22A and the second light-shielding film 22B are cross-hatched (hatched). This liquid crystal display device is different from the liquid crystal display device shown in FIGS. 1A and 1B in that the portion between the overcoat film 14 and the common electrode 25 outside the display region A and inside the sealing material 27 is different. Is that a dummy seal material 31 made of the same material as the seal material 27 is interposed. In this case, spacers 32 and 33 having the same size are dispersedly arranged in the seal member 27 and the dummy seal member 31. Further, the dummy seal material 31 is provided along a necessary side of the four sides of the display area A. Further, both alignment films 15, 26
Is located outside the display area A and inside the dummy seal material 31. In this case, since the dummy seal material 31 is provided, the non-display area B becomes slightly larger, but the following effects are obtained.

First, since the dummy seal material 31 having the spacer 33 is provided inside the seal material 27, that is, just outside the display area A, the dummy seal material 31 is provided between the two substrates 11 and 21 just outside the display area A. The gap is always maintained. Therefore, the two substrates 11 and 21 can be prevented from being depressed immediately outside the display area A. As a result, the display area A near the dummy seal material 31 is displayed.
Display unevenness can be prevented from occurring at the outer peripheral edge portion. Note that both alignment films 15 in the display area A,
Since an in-plane spacer (not shown) is interposed between the substrates 26, the interval between the substrates 11 and 21 in the display area A is naturally always maintained.

Second, since the second light-shielding film 22B is provided over the entire non-display area B, the distance between the overcoat film 14 and the common electrode 25 in the non-display area B is almost the same. . Therefore, as mentioned above,
The same size as the spacers 33 dispersed in the dummy seal material 31 and the spacers 32 dispersed in the seal material 27 can be used. As a result, the dummy seal material 31 can be simultaneously formed by printing using the same material as the seal material 27. Therefore, even if the dummy sealing material 31 is provided, the number of manufacturing steps can be prevented from increasing.

In contrast, in the case of the conventional liquid crystal display device shown in FIGS. 5A and 5B, the interval between the two alignment films 15 and 26 just outside the display area A is:
It is smaller than the distance between the overcoat film 14 and the common electrode 25 in the non-display area B. Therefore, the display area A
In the case where a dummy seal material is provided between the two alignment films 15 and 26 just outside of the seal material, the diameter of the spacer dispersed in the dummy seal material must be smaller than the diameter of the spacer dispersed in the original seal material 27. In addition, the dummy seal material cannot be formed simultaneously with the seal material 27 by printing. The distance between the two alignment films 15 and 26 just outside the display area A is larger than the distance between the two alignment films 15 and 26 in the display area A depending on the presence or absence of the color filter element 23 and the like. For this reason, the same spacer as the in-plane spacer interposed between the two alignment films 15 and 26 in the display region A is used.
Even if they are interposed between the alignment films 26 and 26, they do not become spacers between the alignment films 15 and 26 just outside the display area A.

In the second embodiment, the display area A
Although the case where the dummy seal material 31 is provided along the necessary side among the four sides has been described, the present invention is not limited to this. For example, as shown in FIG. 3, a plurality of dummy seal materials 31 having an arbitrary shape are arranged at predetermined intervals along a required side or along a part of the required side among the four sides of the display area. May be provided in advance. In this case, for example, as shown in FIG. 4, the dummy seal material 31 may be formed in a circular shape. Further, the present invention is not limited to a color liquid crystal display device, and can be applied to a black and white display liquid crystal display device. Further, the present invention can be applied not only to an active matrix type liquid crystal display device but also to a simple matrix type liquid crystal display device and the like. Further, the present invention can be applied to a twisted nematic type or super twisted nematic type liquid crystal display device.

[0014]

As described above, according to the present invention, the non-display area outside the display area, that is, the non-display area outside the display area, is formed by forming the light shielding film provided along the outer periphery of the display area to the outside of the sealing material. Even when the frame is narrowed, light leakage from the vicinity of the outer peripheral edge of the display area can be reliably prevented, and a dummy seal can be formed inside the seal material in the same process using the same material mixed with the same spacer. In addition, it is possible to easily manufacture a liquid crystal display device capable of preventing display unevenness due to gap unevenness at a peripheral portion of a display area.

[Brief description of the drawings]

FIG. 1A is a cross-sectional view showing a main part of a liquid crystal display device according to a first embodiment of the present invention, and FIG. 1B is a bottom view showing a part of an upper substrate thereof.

FIG. 2A is a cross-sectional view showing a main part of a liquid crystal display device according to a second embodiment of the present invention, and FIG. 2B is a bottom view showing a part of an upper substrate thereof.

FIG. 3 is a bottom view of a part of an upper substrate showing a modification of the second embodiment;

FIG. 4 is a bottom view of a part of an upper substrate showing another modification of the second embodiment.

5A is a cross-sectional view showing a part of an example of a conventional liquid crystal display device, and FIG. 5B is a bottom view showing a part of an upper substrate thereof.

[Explanation of symbols]

 Reference Signs List 11 lower substrate 21 upper substrate 22A first light shielding film 22B second light shielding film 27 sealing material 28 liquid crystal A display area B non-display area

Claims (2)

[Claims] A liquid crystal is sealed between the two substrates inside a sealing material, and the liquid crystal is driven in a display area including a plurality of pixels. In a liquid crystal display device that performs display by using a light-shielding film, a light-shielding film is provided in a region extending from at least an outer periphery of the display region to an outer periphery of the display region on a surface of one of the two substrates facing the other substrate. A liquid crystal display device comprising: 2. The liquid crystal display device according to claim 1, wherein a dummy sealing material is formed inside the sealing material in a region where the light shielding film is provided.