JP3469732B2 - Liquid crystal display - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a dot matrix type liquid crystal display device, and more particularly to a liquid crystal display device in which fluctuations in effective gap length are suppressed.

[0002]

2. Description of the Related Art A conventional dot matrix type liquid crystal display device (for example, Japanese Patent Laid-Open No. 7-311378) will be described with reference to FIG. As shown in the figure, this type of liquid crystal display device includes a striped color filter 8 of R, G, and B colors, a plurality of first electrodes 10 arranged in a direction orthogonal to the stripe direction of the color filter 8, and an alignment. A first substrate 2 having a main surface on which a film 11 is formed, and a second substrate having a main surface on which a plurality of second electrodes 14 and an alignment film 15 arranged facing the color filter 8 are formed. 3, a spacer 4 for forming a predetermined gap length is arranged between the main surfaces of the first substrate 2 and the second substrate 3, and a liquid crystal 5 is enclosed in the gap. . Since the portion where the first electrode 10 and the second electrode 14 intersect with each other with the liquid crystal 5 interposed therebetween constitutes a pixel, the spacer 4 maintains the gap length in this pixel region as the effective gap length d to be constant. Is located in.

By the way, this type of liquid crystal display device is
Has a groove (not shown) located between the adjacent first electrodes 10 and a groove 20 located between the adjacent color filters 8 on the main surface of the second substrate 3. The surface also has a groove 16 located between the adjacent second electrodes 14. Since the grooves 16 and 20 form a space d2 longer than the size of the spacer 4, the grooves 16 and 20 are oscillated by an externally applied vibration of the spacer 4 which should normally be located in the pixel region. When the number of spacers 4 captured in the groove increases, it becomes difficult to maintain the effective gap length d accurately. That is, the grooves 16, 20
When the gap length is defined by the spacer 4 captured in the above, the number of places where the gap length is defined to be shorter than the proper proper value increases, and as a result, the thickness of the liquid crystal is likely to be uneven and the display quality is improved. Occurs, which causes a decrease in

[0004]

SUMMARY OF THE INVENTION In view of the above points, the present invention mainly aims to provide a liquid crystal display device having a uniform display of effective gap length and good display quality.

[0005]

According to the present invention, there is provided a first substrate having a stripe-shaped color filter and a main surface having a plurality of first electrodes arranged in a direction orthogonal to the stripe direction of the color filter. A second substrate having a main surface on which a plurality of second electrodes, the number of which is larger than the number of the first electrodes arranged facing the color filter, is formed; the first substrate and the second substrate; In a liquid crystal display device comprising a spacer that forms a gap at a predetermined interval between the main surfaces of the first substrate and a liquid crystal filled in the gap, the main surface along the first electrode of the first substrate is A convex portion having a height substantially equal to the depth of the groove is formed so as to face the groove formed on the main surface of the second substrate along the interval between the second electrodes.

The present invention also includes a first substrate having a stripe-shaped color filter, a plurality of first electrodes arranged in a direction orthogonal to the stripe direction of the color filter, and a main surface on which an alignment film is formed. A second substrate having a main surface on which a plurality of second electrodes and an alignment film arranged facing the color filter are formed, and a predetermined distance between the main surfaces of the first substrate and the second substrate. And a liquid crystal enclosed in the gap, wherein the main surface of the second substrate has a groove along the interval between the second electrodes. The color filters are adjacent to each other, and the adjacent portions are protruded upward corresponding to the depth of the groove to have a mountain shape, and the gap length along the first electrode is constant regardless of the existence of the groove. So that And it features.

[0007]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a sectional view of a liquid crystal display device 1 according to an embodiment of the present invention, and the same parts as those in FIG. 2 are designated by the same reference numerals. As shown in the figure, the liquid crystal display device 1 of this embodiment includes a first substrate 2, a second substrate 3 arranged to face the first substrate 2, a first substrate 2 and a second substrate. It is provided with a plurality of spacers 4 and liquid crystal 5 arranged between the three. Although not shown, in addition to this configuration, a polarizing plate,
A retardation plate, a light diffusion plate, a light source unit, a drive circuit board, and the like can be arranged and configured as necessary.

On the main surface of the first substrate 2, that is, on one surface of the transparent base material 6 such as a glass substrate, a black matrix 7 having a high light-shielding property such as metallic chromium and an opening of the black matrix 7 are covered. The formed color filters 8 of R, G, B three primary colors are formed in stripes. The color filter 8 includes three primary color filters 8r, 8g,
The regions 8b are adjacent to each other in the region shielded by the black matrix 7, and the adjacent portions 8w are formed so as to have a mountain shape protruding upward. Therefore, the adjacent portions 8w having a mountain shape are arranged in a stripe shape along the stripe direction of the color filter 8, but are arranged in a region shielded from light by the black matrix 7, so that the thickness of the adjacent portions 8w is increased. It is possible to prevent the occurrence of optical influence on the color filter 8 that operates.

A transparent protective film 9 is formed on the color filter 8 so as to cover the color filter 8 with a thickness of about 0.5 to 2 μm, and the stripe direction of the color filter 8 is formed on the protective film 9. A plurality of first electrodes 10 for scanning arranged in orthogonal directions are formed with a thickness of about 0.3 to 0.4 μm. An alignment film 11 made of polyimide or the like is formed with a thickness of about 0.1 μm so as to cover them. On the surface of the alignment film 11 located on the main surface of the first substrate 2, a plurality of adjacent portions 8w forming the mountain-shaped shape of the color filter 8 are provided, so that a plurality of protrusions that are relatively upwardly projected as compared with others are provided. The stripe-shaped convex portion 12 is formed. Since the protruding portion 12 is formed by the result that the protruding state of the adjacent portion 8w is flattened by the protective film 9 and the electrode 10 thereon, the protruding height of the protruding portion 12 is the protruding height of the adjacent portion 8w. Fluctuates accordingly. In consideration of this in advance, the protruding height of the adjacent portion 8w is set so that the protruding height of the convex portion 12 is approximately the same as the depth of the groove 16.

On the main surface of the second substrate 3, that is, on one surface of the transparent base material 13 such as a glass substrate, the plurality of first electrodes 1 are formed.
0 in the direction orthogonal to the arrangement direction of the color filters 8, that is, in the same direction as the stripe direction of the color filter 8, a plurality of second electrodes 14 for signals arranged so as to face the respective color filters 8r, 8g, 8b. It is formed with a thickness of about 2 to 0.3 μm. Second electrode 14 for signal corresponding to color display
Are arranged at a pitch that is about three times as large as that of the first scanning electrodes 10, and therefore have a number three times as many as the first scanning electrodes 10. An alignment film 15 made of polyimide or the like is formed with a thickness of about 0.1 μm so as to cover them. Second
The surface of the alignment film 15 located on the main surface of the substrate 3 of
A plurality of grooves 16 having a depth corresponding to the thickness of the electrode 14.
Are formed in stripes along the plurality of second electrodes 14.

The first substrate 2 and the second substrate 3 are sealed with a sealant (not shown) at the peripheral portions of the main surfaces facing each other with a plurality of spacers 4 interposed. The liquid crystal 5 injected from the injection port (not shown) of the sealing agent is sealed in the gap portion between the facing main surfaces. The spacer 4 is provided in the pixel region formed at the intersection between the first electrode 10 and the second electrode 14 with the space between the main surfaces of the first substrate 2 and the second substrate 3 facing each other, particularly the liquid crystal 5 interposed. In order to keep the effective gap length d at a specified value (a value selected from the range of 4 to 12 μm), it has a spherical shape, and its diameter is 4 to 12 μm corresponding to the specified effective gap length d. It is decided by selecting from the range of.

Since the number of the signal second electrodes 14 is about three times that of the scanning first electrodes 10 corresponding to the color display, the number of the grooves 16 is also the number of the scanning first electrodes 10. In comparison with the case of 10, the spacer 4 is trapped in the groove 16 at a rate of about 3 times larger than that in the groove of the first electrode 10.

Conventionally, when a spacer is trapped in the groove 16, as shown in FIG. 2, the depth of the groove 20 between the color filters facing the groove 16 is also added, and the size of the spacer 4 is increased. As a result of the spacer 4 being positioned in the gap length d2 portion exceeding the above, the spacer function could not be exhibited.

However, as described above, this groove 16
Since the adjoining portion 8w of the color filter 8 which is opposed to the above has a mountain shape protruding upward, the influence of the groove 20 between the conventional color filters can be eliminated, and
By offsetting the depth of the groove 16 by the height of the convex portion 12 where the adjacent portion 8w is located, the influence of the depth of the groove 16 can be canceled. Therefore, the convex portion 1
The height of 2 is set to be substantially the same as the depth of the groove 16 (about 0.2 to 0.3 μm, which is almost the same as the thickness of the second electrode 14). By doing so, the groove 1
The gap length d1 in 6 can be set to be substantially the same as the size of the spacer 4, and this gap length d1 can be kept substantially the same as the effective gap length d.

In the above example, the adjacent portion 8w which is projected by the protective film 9 and the electrode 10 which are present on the adjacent portion 8w.
Therefore, the height dimension of the adjacent portion 8w required to offset the depth of the groove 16 needs to be set relatively higher than the height of the convex portion 12. However, the black matrix 7, the color filter 8, the protective film 9, the electrode 1
When the structure or arrangement such as 0 is changed, the height dimension of the adjacent portion 8w is also changed according to the change situation. For example, the height dimension of the adjacent portion 8w is set to be lower as the distance from the color filter 8 to the liquid crystal 5 is shorter, and is set higher when the black matrix 7 is not provided.

Originally, the spacer 4 is supposed to be arranged in the pixel region in order to make the gap length in the pixel region equal to the effective gap length d. However, the spacer 4 is separated from the pixel region by an external force such as vibration and the groove 16 is formed. Occasionally, it will be captured by. However, even if a part of the spacer 4 to be arranged in the pixel region is captured by the groove 16, the gap length d1 of the groove 16 is set to be the effective gap length d. 4 can also function as a spacer that holds the effective gap length d of the pixel region. As a result, the spacers 4 mainly in the pixel area
And the spacer 4 in the auxiliary groove 16 keeps the gap length along the first electrode 10 at the effective gap length d.

Further, of the grooves located around the pixel region, the ratio of the groove 16 is about 70 to 80%, which is very large. Therefore, the gap length variation caused by the groove 16 portion is as described above. By improving, the gap length variation can be greatly improved. In particular, when increasing the size of the screen, it is required to keep the effective gap length d uniform over the entire range of the screen. Therefore, by improving the gap length variation as described above, the display unevenness on the liquid crystal screen is reduced. Therefore, the display quality can be kept good.

The present invention is not limited to the above embodiments, and the structure and arrangement of the black matrix 7, the color filter 8, the protective film 9, the electrode 10, etc. may be modified within the scope of the present invention. You can also

[0019]

As described above, according to the present invention, the gap length variation due to the groove formed along the interval portion of the second electrode can be eliminated by effectively utilizing the color filter, It is possible to keep the effective gap length uniform in the entire range of the screen, reduce display unevenness on the liquid crystal screen, and maintain good display quality.

[Brief description of drawings]

FIG. 1 is a cross-sectional view of essential parts of a liquid crystal display device according to an embodiment of the present invention.

FIG. 2 is a cross-sectional view of a main part of a liquid crystal display device according to a conventional example.

[Explanation of symbols] 1 Liquid crystal display 2 First substrate 3 Second substrate 4 spacers 5 liquid crystal 8 color filters 10 First electrode 12 convex 14 Second electrode 16 grooves

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Masayuki Kametani               3-201 Minamiyoshikata, Tottori City, Tottori Prefecture               Tori Sanyo Electric Co., Ltd.                (56) Reference literature JP-A-7-311378 (JP, A)                 JP-A-2-87118 (JP, A)                 JP-A-7-191332 (JP, A)                 JP-A-8-122753 (JP, A)                 JP-A-8-122763 (JP, A)

Claims (2)

(57) [Claims] 1. A stripe-shaped color filter, a first substrate having a main surface on which a plurality of first electrodes arranged in a direction orthogonal to the stripe direction of the color filter are formed, and facing the color filter. The first arranged
A second substrate having a main surface on which a plurality of second electrodes, the number of which is larger than the number of electrodes, are formed, and a spacer for forming a gap at a predetermined interval between the main surfaces of the first substrate and the second substrate And a liquid crystal enclosed in the gap, in a liquid crystal display device, the main surface of the first substrate along the first electrode,
A liquid crystal display device, wherein a convex portion having a height substantially equal to a depth of the groove is formed so as to face a groove formed on the main surface of the second substrate along a space between the second electrodes. . 2. A stripe-shaped color filter, a first substrate having a main surface on which a plurality of first electrodes arranged in a direction orthogonal to the stripe direction of the color filter are formed, and facing the color filter. A second substrate having a main surface on which a plurality of arranged second electrodes are formed, and a spacer for forming a gap at a predetermined interval between the main surfaces of the first substrate and the second substrate, A liquid crystal display device having a liquid crystal enclosed in the gap, wherein the color filter is adjacent to each other in the liquid crystal display device having a groove along the interval between the second electrodes on the main surface of the second substrate; A liquid crystal characterized in that an adjacent portion is protruded upward in accordance with the depth of the groove to have a mountain shape so that a gap along the first electrode is constant regardless of the existence of the groove. Display device.