JP2002350882A - Liquid crystal display panel - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a liquid crystal display panel wherein the problem of the unevenness generated on the periphery of an injection port of a liquid crystal and a sealing material can be eliminated. SOLUTION: In the liquid crystal display panel 1 wherein two transparent substrates 2 having at least a transparent electrode and an alignment layer are stuck to each other with a prescribed gap via a frame-shaped sealing material 3 disposed in a non-display area enclosing a display area and the liquid crystal is injected in the gap by capping the injection port 4 formed in the sealing material 3, a frame-shaped second sealing material 3B having a second injection port 4B in the position which is not opposed to the injection port 4A formed in the sealing material 3A is formed in the non-display area inside the frame-shaped sealing material 3A.

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 panel having a structure effective as a measure against unevenness that has occurred near a sealing material for bonding two transparent substrates.

[0002]

2. Description of the Related Art First, the structure of a general liquid crystal display panel will be briefly described with reference to FIG.

The liquid crystal display panel 11 has two transparent substrates 12 arranged substantially in parallel at an interval, and the two transparent substrates 12 are made of a transparent material such as ITO (indium tin oxide). An electrode and an alignment film are provided.

[0006] The outer periphery between the transparent substrates 12 is adhered to each other with a predetermined gap provided by a frame-shaped sealing material 13 and sealed, and both the transparent substrates 12 and the sealing material 13 are sealed.
The liquid crystal is sealed in the enclosed space surrounded by. FIG. 6 shows the positional relationship between the transparent substrate 12 and the sealing material 13, and the illustration of the other components is omitted.

Conventionally, a TN type or STN type liquid crystal display panel 11 has often been used as the liquid crystal display panel 11 having such a configuration. In recent years, however, a chiral agent comprising an optically active substance has been added to nematic liquid crystal. By
Many reflective liquid crystal display panels 11 using a chiral nematic liquid crystal that forms a cholesteric phase at room temperature have been researched and developed.

In the reflection type liquid crystal display panel 11 using the chiral nematic liquid crystal, a predetermined voltage is applied to change the liquid crystal phase between a planar state exhibiting selective reflection and a focal conic state exhibiting a fine scattering state. Can be displayed.

In brief, the principle of the selective reflection is described. The chiral nematic liquid crystal is sandwiched between a pair of substrates, and the director, which is the arrangement direction of the chiral nematic liquid crystal, is the central axis of the twist that rotates at regular intervals. When arranged so that the helical axis (spiral axis) is perpendicular to the substrate on average, circularly polarized light corresponding to the direction of the twist is reflected. The center wavelength of the reflected light is the distance (pitch) on the helical axis during one rotation of the director of the chiral nematic liquid crystal parallel to the substrate and the two-dimensional plane parallel to the substrate surface of the nematic liquid crystal. And the average refractive index. The phenomenon that such a chiral nematic liquid crystal reflects circularly polarized light of a specific wavelength based on its pitch and the refractive index of the liquid crystal is called selective reflection.

The liquid crystal display panel 11 using a chiral nematic liquid crystal having such properties has a panel design substantially the same as that of a general TN type or STN type liquid crystal display panel 11 for components other than the liquid crystal. In addition, an alignment process and a deflection film are not necessary in the process, and the production can be performed without requiring any special production equipment.

[0009]

However, the liquid crystal display panel 11 using a chiral nematic liquid crystal needs to apply a higher voltage than the above-mentioned general TN type or STN type liquid crystal display panel. Therefore, a liquid crystal having a large dielectric constant is generally used as the chiral nematic liquid crystal for the purpose of saving power. Liquid crystals having a large dielectric constant have a sensitive property of easily reacting with other substances, and are liable to undergo hydrolysis.

A liquid crystal having a large dielectric constant has a high affinity for ionic impurities and contains many impurities such as hydrolyzate and ionic impurities. Then, these impurities are adsorbed on the surface of the alignment film in the display region near the liquid crystal injection port 14, and a fan-shaped unevenness as shown by hatching in the injection port 14 portion in FIG.

In a reliability test of a product in an environment of high temperature and high humidity (80 ° C. × 90%), in addition to the problem of the fan-shaped unevenness, depending on the type of liquid crystal, moisture is sealed. The liquid crystal enters the display region from the material 13, and the liquid crystal is hydrolyzed, thereby causing a new problem that unevenness is generated in a portion of the inner circumference of the sealing material 13 indicated by hatching in FIG. 6.

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and an object of the present invention is to provide a liquid crystal display panel which can solve the problem of unevenness occurring around a liquid crystal injection port and a sealing material of the liquid crystal display panel. It is assumed that.

[0013]

In order to achieve the above object, a liquid crystal display panel according to a first aspect of the present invention is characterized in that at least two transparent substrates having a transparent electrode and an alignment film surround a display area. A liquid crystal display panel in which liquid crystal is injected into the gap by providing a predetermined gap through a frame-shaped sealing material arranged in the display area and sealing the injection port of the sealing material, In the non-display area inside the frame-shaped sealing material, a frame-shaped second sealing material having a second injection port is formed at a position not facing the injection port of the sealing material. .

By adopting such a configuration, the positions of the injection port of the sealing material formed on the outside and the injection port of the second sealing material formed on the inside are shifted, and the liquid crystal to be injected is shifted. Has a configuration in which a flow distance is provided before reaching the display area, so that the liquid crystal to be injected can adsorb impurities that cause unevenness before reaching the display area. Also, the invasion of moisture, which causes unevenness in the peripheral portion of the sealing material, is diffused into the liquid crystal in a gap between the sealing material formed outside and the second sealing material formed inside. Can be. Therefore, it is possible to prevent the display quality from deteriorating due to the occurrence of the unevenness in the display area in the frame-shaped second sealing material formed inward.

According to a second aspect of the present invention, there is provided a liquid crystal display panel according to the first aspect, wherein the sealing material is formed in a gap between the sealing material and the second sealing material. In the liquid crystal flow path from the inlet to the injection port of the second sealant, a bank wall for blocking the flow of liquid crystal is formed in the liquid crystal flow path formed at a short distance.

By adopting such a configuration, the flow path from the injection port of the sealing material formed outside to the injection port of the second sealing material of the injected liquid crystal is formed by the sealing material and the second sealing material. In particular, by using only the flow path of the long-distance liquid crystal formed in the gap with the sealing material, it is possible to obtain a time for allowing the impurities contained in the liquid crystal to be adsorbed on the alignment film. It is possible to prevent non-uniformity caused by the adsorption of the light from reaching the display area.

A liquid crystal display panel 1 according to claim 3.
The feature of the liquid crystal display panel according to claim 1,
Of the liquid crystal flow paths from the sealing material injection port formed in the gap between the sealing material and the second sealing material to the second sealing material injection port, the liquid crystal flow paths formed at short distances At least one obstruction wall for meandering and flowing the liquid crystal therein.

By adopting such a configuration, the liquid crystal injected from the injection port of the sealing material formed outside can be used for the short distance formed in the gap between the sealing material and the second sealing material. Even when distributing through liquid crystal distribution channels,
By meandering in the flow path, it is possible to obtain time for allowing the impurities included in the liquid crystal to be adsorbed on the alignment film, and to surely ensure that unevenness due to the adsorption of the impurities by the alignment film reaches the display region. Can be prevented.

[0019]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a liquid crystal display panel 1 according to the present invention will be described below with reference to FIGS.

FIG. 1 shows a first embodiment of a liquid crystal display panel 1 according to the present invention.
It is explanatory drawing which shows the seal structure in embodiment.

Between the two transparent substrates 2 of the liquid crystal display panel 1 shown in FIG. 1, a frame-shaped sealing material 3 having an injection port 4 is formed in two layers, and a sealing material formed outside is formed. The material 3 (hereinafter, first sealing material 3A) has a frame shape having a liquid crystal injection port 4 (hereinafter, first injection port 4A) projecting outward, and is similar to the conventional frame-shaped sealing material 3. It is formed by design and process. In addition, the sealing material 3 formed inside is
(Hereinafter, the second sealing material 3B) is formed in a frame shape for opening the liquid crystal injection port 4 (hereinafter, the second injection port 4B). In the present embodiment, the second injection port 4B is The first inlet 4A is formed so as to open on the opposite side to the opening direction. More specifically, the second injection port 4B is located on the side of the second sealing material 3B extending substantially parallel to the side of the first sealing material 3A that is adjacent to the side opposite to the side on which the first injection port 4A is formed. It is formed at a position substantially symmetric with the first injection port 4A.

The opening position of the second inlet 4B is
The position is not limited to the position of the present embodiment, and may be any position that does not face the first injection port 4A. Therefore, as shown in FIG. 2, on the side of the second sealing material 3B extending substantially parallel to the side where the first inlet 4A is formed, the position is shifted from the first inlet 4A. Alternatively, as shown in FIG. 3, it may be formed on the side of the second sealing material 3B extending substantially perpendicular to the side on which the first inlet 4A is formed.

The inlet 4B of the second sealing material 3B is
The liquid crystal sealed by closing the first injection port 4A of the first sealing material 3A is not limited to the convection in the closed space surrounded by the transparent substrate 2 and the first sealing material 3A. It is necessary to design, and for that purpose, it seems that it is most appropriate to form only one inlet 4 of the second sealing material 3B.

The first sealing material 3A and the second sealing material 3B are spaced from each other by a sufficient distance for the liquid crystal to be injected to flow therethrough. It is formed in a non-display area on the alignment film of the liquid crystal display panel 1.

Note that the liquid crystal display panel 1 of the present embodiment is
After the liquid crystal is injected, the injection port 4 sealed by the sealing material is the first injection port 4A of the first sealing material 3A formed outside, and the second injection port 4B is kept open. Becomes

In the liquid crystal display panel 1 of the present embodiment having such a configuration, the formation positions of the first injection port 4A of the first sealing material 3A and the second injection port 4B of the second sealing material 3B are shifted. Since the flow distance of the liquid crystal is provided before the injected liquid crystal reaches the display area, impurities causing unevenness may be generated on the surface of the alignment film before the injected liquid crystal reaches the display area. And the second inlet 4B
Since the liquid crystal injected into the display region from the liquid crystal is purified, it is possible to prevent the display region in the second sealing material 3B from causing the unevenness caused by the adsorption of the impurities and deteriorating the display quality. Can be.

The unevenness that has occurred in the peripheral portion of the sealant is also caused by the infiltration of moisture from the first sealant 3A formed outside to the inside of the first sealant 3A and the second sealant 3B. The liquid crystal can be diffused into the liquid crystal in the gap portion, and the momentum of the second sealing material 3B can be eliminated. Therefore, it is possible to prevent the unevenness that has occurred on the entire periphery of the seal from occurring in the display area in the second seal material 3 and deteriorating the display quality.

FIG. 4 shows a liquid crystal display panel 1 of the present invention.
It is explanatory drawing which shows the seal structure in 2nd Embodiment.

The liquid crystal display panel 1 shown in FIG.
Of the two clockwise and counterclockwise flow paths 7 from the first inlet 4A to the second inlet 4B formed in the gap between the sealing material 3A and the second sealing material 3B, The sealing structure has a bank wall 5 for blocking the flow of liquid crystal formed in the formed clockwise circulation channel 7.

More specifically, of the double frame-shaped sealing material 3, a first injection port opening to the first sealing material formed outside is formed by moving the first injection port to either side. Second injection port 4B opening to second sealing material 3B formed inward
With the first injection port 4 of the first sealing material 3A formed outside.
On the side extending substantially parallel to the side where A is formed, the opening is shifted to the side opposite to the first injection port 4A. The liquid crystal display panel 1 according to the present embodiment further includes a first inlet 4A to a second inlet in a flow path 7 formed in a gap between the first seal 3A and the second seal 3B. A bank wall 5 for blocking the flow of the liquid crystal is formed in the clockwise circulation path 7 formed in a short distance among the two circulation paths 7 clockwise and counterclockwise up to 4B.

In the liquid crystal display panel 1 of this embodiment having such a configuration, the flow path 7 of the liquid crystal injected from the first injection port 4A to the second injection port 4B is formed by the first sealing material 3A. By providing only a long-distance flow path 7 formed counterclockwise in the figure in the gap between the first sealing material 3B and the second seal material 3B, the impurities contained in the liquid crystal are adsorbed on the surface of the alignment film disposed in the gap. Since a sufficient time and distance can be obtained, and the liquid crystal injected into the display area from the second injection port 4B can be purified, impurities in the display area due to the alignment film can be surely obtained. It is possible to prevent the occurrence of non-uniformity due to the adsorption of the particles.

FIG. 5 is an explanatory view showing a seal structure of a liquid crystal display panel 1 according to a third embodiment of the present invention.

The liquid crystal display panel 1 shown in FIG.
Of the liquid crystal flow paths 7 from the first injection port 4A to the second injection port 4B formed in the gap between the seal material 3A and the second seal material 3B, the flow paths 7 are formed in a short distance. The seal structure has at least one obstacle wall for meandering and flowing the liquid crystal.

More specifically, the liquid crystal display panel 1 of the present embodiment shown in FIG. 5 is different from the liquid crystal display panel of the second embodiment in that the bank wall 5 in the second embodiment is replaced by a clockwise flow path 7 formed in the short distance. A plurality of obstruction walls 6 for meandering and flowing the liquid crystal therein are formed. The obstacle wall 6 is provided between the first sealing member 3 and the gap forming the flow path 7 of the liquid crystal.
A first obstruction wall 6 </ b> A, which is formed to be slightly perpendicular to the width direction of the gap and substantially perpendicularly from the inner wall of the second seal material A, and the second sealing material 3.
The second obstacle wall 6B is formed substantially perpendicularly from the outer wall of B and slightly shorter than the width of the gap. By arranging these obstacle walls 6A and 6B alternately, a clockwise liquid crystal flow path 7 formed in a short distance.
Inside, a path for meandering and flowing the liquid crystal is formed.

In the liquid crystal display panel 1 of this embodiment having such a structure, the liquid crystal injected from the first injection port 4A is formed in the gap between the first sealing material 3A and the second sealing material 3. Even in the case of flowing through the short flow path 7, the meandering in the flow path 7 can sufficiently obtain the time and distance for allowing the impurities contained in the liquid crystal to be adsorbed on the alignment film. In addition, it is possible to reliably prevent unevenness due to the adsorption of impurities by the alignment film from reaching the display region.

Here, results of a reliability test of the liquid crystal display panel 1 of the present invention will be described.

In this test, the cell size was 60 mm × 30
mm, and the first sealing material 3A is formed by printing so that the sealing width is 0.8 to 1.0 mm.
The second sealing material 3B is formed by printing so that the width is 0.3 to 1.0 mm. Then, the five types of liquid crystal display panels 1 having the respective seal structures shown in FIGS. 1 to 5 of the above-described embodiment of the present invention, the first seal material 3A and the second seal material 3B are formed in a double form. Further, an experiment was performed using a total of six types of liquid crystal display panels including one type of test liquid crystal display panel in which the first injection port 4A and the second injection port 4B were formed at the same position.

The test consisted of being left for 1000 hours in a high-temperature, high-humidity environment of 80 ° C. × 90%.

As a result, the liquid crystal display panel prepared for the test, in which the first injection port 4A and the second injection port 4B are positioned so as to overlap each other, is placed within the display area of the liquid crystal display panel from the first sealing material 3A. There was no influence on the unevenness which was considered to be caused by the hydrolysis of the infiltrated water, but the fan-shaped unevenness generated at the injection port 4 affected the unevenness.

On the other hand, in the liquid crystal display panel 1 having the sealing structure shown in FIGS. 1 to 5 shown in the embodiment of the present invention, fan-shaped unevenness, hydrolysis of water entering from the periphery of the first sealing material. Thus, good display quality was able to be shown without affecting any of the unevenness caused by the above.

The present invention is not limited to the above-described embodiment, but can be variously modified as needed.

The number of obstruction walls for meandering and distributing the liquid crystal is not limited to the number of the present embodiment, and the flow path of the liquid crystal forming the obstruction wall is also particularly limited to the first sealing material. Not limited to a flow path formed with a short distance from the second seal material, for example, an obstacle wall can be formed in any flow path as needed.

[0043]

As described above, according to the liquid crystal display panel of the present invention, by the time the liquid crystal to be injected reaches the inside of the display area, it is sufficient to adsorb impurities causing unevenness to the surface of the alignment film. By providing a configuration in which a circulation distance is provided and a configuration in which moisture that penetrates from the peripheral portion of the sealing material is diffused into the liquid crystal, unevenness is exerted on the display area in the frame-shaped second sealing material. It is possible to obtain a good display quality by preventing the display from spreading.

[Brief description of the drawings]

FIG. 1 is an explanatory view showing a seal structure in a first embodiment of a liquid crystal display panel of the present invention.

FIG. 2 is an explanatory view showing another example of the first embodiment.

FIG. 3 is an explanatory view showing still another example of the first embodiment.

FIG. 4 is an explanatory view showing a seal structure in a second embodiment of the liquid crystal display panel of the present invention.

FIG. 5 is an explanatory view showing a seal structure in a third embodiment of the liquid crystal display panel of the present invention.

FIG. 6 is an explanatory view showing a seal structure and a problem in a conventional liquid crystal display panel.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Liquid crystal display panel 2 Transparent substrate 3 Sealing material 3A 1st sealing material 3B 2nd sealing material 4 Injection port 4A 1st injection port 4B 2nd injection port 5 Embankment wall 6 Obstacle wall 6A 1st obstacle wall 6B 2nd obstacle wall 7 Distribution channel

Claims (3)

[Claims] 1. A sealing method comprising the steps of: bonding two transparent substrates having at least a transparent electrode and an alignment film with a predetermined gap provided therebetween through a frame-shaped sealing material disposed in a non-display area surrounding a display area; In a liquid crystal display panel in which liquid crystal is injected into the gap by sealing an injection port of a material, the non-display region inside the frame-shaped sealing material further does not face the injection port of the sealing material. A liquid crystal display panel, wherein a frame-shaped second sealing material having a second injection port at a position is formed. 2. A liquid crystal flow path, which is formed at a short distance from a liquid crystal flow path from an inlet of the seal material formed in a gap between the seal material and the second seal material to an inlet of the second seal material. 2. The liquid crystal display panel according to claim 1, wherein a bank wall for blocking the flow of the liquid crystal is formed in the flow path of the liquid crystal. 3. The liquid crystal flow path from the inlet of the seal material formed in the gap between the seal material and the second seal material to the inlet of the second seal material is formed at a short distance. The liquid crystal display panel according to claim 1, wherein at least one obstacle wall for meandering and flowing the liquid crystal is formed in the flow path of the liquid crystal.