JPH07209659A - Liquid crystal display panel - Google Patents

Abstract

PURPOSE:To prevent a sealant of a liquid crystal display panel from infiltrating into the inside. CONSTITUTION:A couple of upper and lower substrates 1 and 2 are arranged opposite each other across a specific gap to constitute a panel. This panel is sectioned into a center display area 3 and a peripheral area 4 which surrounds it. A seal material 5 is arranged along the peripheral area 4 and both the substrates 1 and 2 are adhered to each other to form an internal space containing the display the display area 3. This seal material 5 is partially removed to form an injection hole 6. Liquid crystal is injected into the internal space through the injection hole 6 to fill the display area 3. A sealant 7 is charged in the injection hole 6. A grooved recessed part 8 is formed in at least one substrate 2 across between the injection hole 6 and display area 3 to prevent the sealant 7 from infiltrating into the inside.

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. More specifically, the present invention relates to a sealing structure for liquid crystal injected into a gap between a pair of substrates bonded to each other.

[0002]

2. Description of the Related Art A general structure of a conventional liquid crystal display panel will be briefly described with reference to FIG. As shown in the figure, the upper glass substrate 101 and the lower glass substrate 102 are arranged to face each other with a predetermined gap therebetween to form a panel. This panel is divided into a central display area 103 and a peripheral area 104 surrounding the display area 103. Sealing material 10 along the peripheral region 104
5, the upper and lower substrates 101 and 102 are bonded to each other to form an internal space including the display area 103. The sealing material 105 is partially removed in advance and an injection port 106 is provided. Liquid crystal is introduced into the internal space through the injection port 106 to fill the display area 103. This liquid crystal injection is performed, for example, after the internal space is evacuated and the injection port 1
It is carried out by bringing the liquid crystal into contact with 06 and returning the atmosphere to atmospheric pressure. After injecting the liquid crystal, the injection port 106 is filled with a sealing material 107 made of epoxy resin, acrylic resin, or the like.

[0003]

The filling of the sealing material 107 utilizes the capillary phenomenon. In addition to this, a pressure difference or a temperature difference is given between the inner space of the panel and the outside to promote filling. As time passes, the sealing material 107 becomes the injection port 106.
After entering the inside of the container, a curing process is performed at the filling stage to fix it. However, the entry speed of the sealing material 107 varies depending on the individual panel, and in some cases, as shown in FIG.
As shown in, there is a case where the display area 103 is invaded. The liquid crystal filling the display area 103 is partially filled with the sealing material 107.
However, there is a problem that a normal image display cannot be performed and a display defect occurs because the image is replaced with.

As a measure for preventing the sealing material from squeezing out, a structure has been proposed in which a bank 108 is provided between the injection port 106 and the display region 103 as shown in FIG. Bank 108
Is formed at the same time as the sealant 105 is applied by printing,
It intervenes over the gap between the upper and lower substrates 101, 102. Although the bank 108 is effective in protruding a small amount of the sealing material 107, if it exceeds a certain amount, it enters the display area 103 as shown in the drawing. Further, in a small-sized high-definition liquid crystal display panel having a diagonal dimension of 1 inch or less, it may not be possible to secure a space for installing the bank 108. Alternatively, interposing the bank 108 increases the size of the substrate, which is disadvantageous in terms of cost.

[0005]

SUMMARY OF THE INVENTION In view of the above-mentioned problems of the prior art, it is an object of the present invention to effectively prevent the sealing material from protruding to the display area of a liquid crystal display panel.
The following measures have been taken in order to achieve this object. That is, the liquid crystal display panel according to the present invention has, as a basic configuration, a pair of substrates, a sealing material, a liquid crystal, and a sealing material. The pair of substrates are arranged to face each other with a predetermined gap therebetween to form a panel. The panel has a central display area and a peripheral area surrounding it. The sealing material is disposed along the peripheral area and adheres the two substrates to each other to form an internal space including the display area. An inlet is provided by partially removing the sealing material in advance. The liquid crystal is introduced into the internal space through this inlet and fills the display area. The sealing material is filled in the injection port to complete the sealed structure of the liquid crystal display panel. As a feature of the present invention, at least one of the substrates is provided with a recess for preventing the encapsulant from entering so as to cross between the injection port and the display region. For example, the recess can be provided by patterning a groove in an insulating film that covers the substrate. Alternatively, the recess may be provided by directly forming a groove on the substrate by etching or half dicing.

[0006]

According to the present invention, the recess is provided in at least one of the substrates so as to traverse between the injection port and the display region.
Therefore, the substrate gap size at the injection port is relatively reduced as compared to the recessed substrate gap size. For this reason, the liquid sealing material filled in the inlet cannot move forward from the groove-shaped concave portion due to the effect of surface tension. When the filled sealing material reaches the concave portion, it is guided along the edge of the groove-shaped concave portion by the capillary phenomenon so as to be orthogonal to the filling direction. In other words, the sealing material cannot advance beyond the recess due to the surface tension, and does not reach the display area. As a result, it becomes possible to effectively prevent the display defect due to the penetration of the sealing material, which has been a problem in the past.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will be described in detail below with reference to the drawings. FIG. 1 shows a structure of a liquid crystal display panel according to the present invention, where (A) is a plan view and (B) is a plan view.
Is a sectional view. As shown in (A), the upper glass substrate 1 and the lower glass substrate 2 are arranged to face each other with a predetermined gap therebetween to form a liquid crystal display panel. The panel is divided into a central display area 3 and a peripheral area 4 surrounding the display area 3. A sealing material 5 is arranged along the peripheral region 4, and the upper and lower substrates 1 and 2 are bonded to each other to form an internal space including the display region 3. The sealing material 5 is partially removed in advance and an injection port 6 is provided. Liquid crystal is introduced into the internal space through the injection port 6 to fill the display area 3. Further, the filling material 6 is filled with the sealing material 7 to complete the sealed state of the liquid crystal display panel. A feature of the present invention is that at least one of the substrates (for example, the lower glass substrate 2) is provided with a recess 8 for preventing the encapsulating material 7 from penetrating so as to traverse between the inlet 6 and the display region 3. . The recess 8 has a groove shape.

Continuing to refer to FIG. 1A, a method for manufacturing a liquid crystal display panel according to the present invention will be described in detail. First, the display area 3 is formed on the surface of the lower glass substrate 2. At this time, the recess 8 is also formed at the same time. Next, the sealing material 5 is applied along the peripheral region 4 surrounding the display region 3 and the recess 8 by screen printing or the like. The sealing material 5 is made of an ultraviolet curable adhesive or a thermosetting adhesive. Next, the upper glass substrate 1 is overlaid and the sealing material 5 is cured to bond the upper and lower substrates 1 and 2 to each other. In addition, when the seal material 5 is screen-printed, the injection port 6 is formed,
Pattern the screen mask. Then, the interior space including the display region 3 is evacuated to a vacuum, and the outside of the panel is returned to atmospheric pressure with the liquid crystal contacting the inlet 6. As a result, the liquid crystal is vacuum-injected into the internal space to fill the display area 3. Finally, the injection port 6 is filled with a liquid sealing material 7 and sealed. The liquid sealing material 7 enters the injection port 6 by a capillary phenomenon. At this time, in order to ensure the filling, a pressure difference or a temperature difference may be provided between the internal space of the liquid crystal panel and the outside. As the sealing material 7, for example, an ultraviolet curable acrylic resin can be used. Since the liquid sealing material 7 filled in the injection port 6 receives the surface tension, it cannot pass over the concave portion 8 and is guided laterally in parallel with the groove. This prevents the sealing material 7 from protruding to the display area 3. Finally, the sealing material 7 is cured by irradiating ultraviolet rays to complete the sealing process. Even if the sealing material 7 filled in the inlet 6 is left in an uncured state for a long time, there is no fear that it will enter the display region 3 beyond the recess 8. Therefore, unlike the conventional case, it is not necessary to manage the filling time, and a large number of pieces can be collectively cured, which leads to streamlining of the process.

FIG. 1B schematically shows a sectional structure of the liquid crystal display panel shown in FIG. The upper and lower glass substrates 1 and 2 are bonded to each other by a sealing material 5. The gap between the substrates 1 and 2 is filled with the liquid crystal 9 as described above, and is sealed by the sealing material 7. The above-mentioned recess 8 is a groove formed in the insulating film 10 that covers the lower glass substrate 2. The insulating film 10 is made of an ultraviolet curable acrylic resin and is formed to a thickness of about 1 μm. This insulating film 10 is directly exposed and developed to form groove-shaped recesses 8. The insulating film 10 is not limited to the resin material described above, and various organic materials or inorganic materials that can be patterned can be used. As the inorganic material, for example, a glass film or a silicon nitride film can be used. The recess 8 can be precisely and finely patterned by photolithography and etching. Therefore, unlike the bank 108 shown in FIG. 6, an extra space is not particularly required, and the bank 108 can be easily provided in a small and high definition active matrix liquid crystal display panel. Further, there is no need to increase the board size. The substrate gap size of the liquid crystal display panel is set to about 5 μm, for example. On the other hand, the thickness of the insulating film 10 is, for example, 1 μm.
The depth of the recess 8 corresponds to the thickness of the insulating film 10. Since there is a considerable difference in the substrate gap size between the inlet 6 and the concave portion 8, the sealing material 7 is strongly affected by the surface tension and does not flow over the concave portion 8 into the inside.

FIG. 2 is a schematic sectional view showing another embodiment of the liquid crystal display panel according to the present invention. The basic structure is the same as that of the previous embodiment shown in FIG. 1B, and corresponding parts are designated by corresponding reference numerals to facilitate understanding. The different point is that the groove is directly formed on the surface of the lower glass substrate 2 and constitutes the above-mentioned concave portion 8. This groove is obtained, for example, by directly etching the glass substrate 2 with hydrofluoric acid or the like. Alternatively, the glass substrate 2
The surface may be ground by half dicing or the like.

FIG. 3 is a schematic partial sectional view showing a specific structural example of the liquid crystal display panel shown in FIG. It should be noted that this specific example is given for the purpose of explanation, and the present invention is not limited to this. For ease of understanding, the central display area and the peripheral area where the inlet is provided are shown separately. In the display area, pixel electrodes 22 are formed in a matrix on the surface of a lower insulating substrate 21 made of quartz glass or the like.
Further, the thin film transistors 23 for switching and driving the individual pixel electrodes 22 are also formed correspondingly. An intermediate planarization layer 24 is interposed between the upper layer to which the pixel electrode 22 belongs and the lower layer to which the thin film transistor 23 belongs. The flattening layer 24 is made of, for example, an ultraviolet curable acrylic resin, and a contact hole can be opened by exposure and development processing. The upper pixel electrode 22 and the lower thin film transistor 23 are electrically connected to each other through the contact hole. The counter substrate 25 is bonded to the lower insulating substrate 21 with a predetermined gap. A counter electrode 26 is previously formed on the inner surface of the counter substrate 25. Both boards 21,2
The liquid crystal layer 27 is held between 5 to form an active matrix type display region.

On the other hand, in the peripheral region, the flattening layer 2 made of the acrylic resin is formed on the surface of the lower insulating substrate 21.
4 is extended. The flattening layer 24 is patterned into a predetermined shape at the same time when the contact hole is opened, and a groove-shaped recess 28 is provided. By interposing the recess 28, it is possible to effectively prevent the sealing material 29 from entering the inside.

FIG. 4 schematically shows the planar shape of the active matrix type liquid crystal display panel shown in FIG. As described above, the pixel electrodes 22 are integrated and formed in a matrix on the lower insulating substrate 21. Corresponding to this, a thin film transistor 23 for switching driving is also integrally formed. Gate line 30 along the row direction
And the signal line 31 is also patterned along the column direction. The gate electrode of each thin film transistor 23 corresponds to the corresponding gate line 3
0, the source electrode is connected to the corresponding signal line 31, and the drain electrode is connected to the corresponding pixel electrode 22. A vertical drive circuit 32 and a horizontal drive circuit 33, which are also thin film transistors, are integrally formed on the surface of the insulating substrate 21. The vertical drive circuit 32 has a gate line 3
The thin film transistors 23 are line-sequentially selected for each row via 0. On the other hand, the horizontal driving circuit 33 transmits the pixel electrode 2 through the selected thin film transistor 23 through the signal line 31.
The image signal is written in 2. As a result, a desired display operation can be performed. The vertical drive circuit 32 and the horizontal drive circuit 33
A lead-out electrode 34 is connected to this so as to establish electrical continuity with the outside.

A sealing material 35 is arranged along the peripheral region surrounding the display region having such a structure, and the lower insulating substrate 21 and the upper counter substrate 25 are bonded to each other. A part of the sealing material 35 is cut out and serves as an injection port. As described above, the groove-shaped concave portion 28 is patterned on the surface of the insulating substrate 21 so as to divide the injection port and the display region, and prevents the sealing material 29 from entering the inside.

[0015]

As described above, according to the present invention, at least one of the substrates is provided with a groove-shaped recess so as to cross the space between the injection port and the display region, thereby preventing the encapsulating material from entering the inside. The effect is that you can do it. The difference in the substrate gap size between the inlet and the recess is utilized to prevent the intrusion of the sealing material due to the effect of surface tension. Since the liquid encapsulating material does not proceed to the inside even if left for a long time, there is an effect that time management in the encapsulation process is unnecessary and the process can be rationalized. Since the groove-shaped recess can be formed extremely compactly, it can be applied to a small-sized liquid crystal display panel, and cost reduction can be realized by downsizing the outer shape.

[Brief description of drawings]

FIG. 1 is a schematic plan view and a sectional view showing an embodiment of a liquid crystal display panel according to the present invention.

FIG. 2 is a schematic sectional view showing another embodiment of the liquid crystal display panel according to the present invention.

FIG. 3 is a cross-sectional view showing a specific configuration example of the liquid crystal display panel shown in FIG.

FIG. 4 is a plan view showing a similar specific configuration example.

FIG. 5 is a plan view showing an example of a conventional liquid crystal display panel.

FIG. 6 is a plan view showing another example of a conventional liquid crystal display panel.

[Explanation of symbols]

 1 Substrate 2 Substrate 3 Display Area 4 Peripheral Area 5 Sealing Material 6 Injection Port 7 Sealing Material 8 Recess 9 Liquid Crystal 10 Insulating Film

Claims (3)

[Claims] 1. A pair of substrates, which are arranged to face each other with a predetermined gap therebetween and have a display region and a peripheral region surrounding the display region,
A sealing material that is disposed along the peripheral area and adheres the two substrates to each other to form an internal space that includes the display area, and an injection port provided by partially removing the sealing material in advance. In a liquid crystal display panel including a liquid crystal introduced into an internal space and a sealing material filled in the injection port, the sealing material invades at least one substrate so as to cross between the injection port and the display region. A liquid crystal display panel, which is provided with a concave portion for preventing the above. 2. The liquid crystal display panel according to claim 1, wherein the recess comprises a groove formed in an insulating film that covers the substrate. 3. The liquid crystal display panel according to claim 1, wherein the recess comprises a groove formed directly on the substrate.