JP3383055B2 - LCD panel - Google Patents

Description

Description: 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. 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 it. Sealing material 10 along the peripheral area 104
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 has been partially removed in advance, and an inlet 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, by evacuating the internal space and then filling the injection port 1.
This is carried out by bringing the liquid crystal into contact with 06 and returning the surroundings to atmospheric pressure. After the liquid crystal is injected, a sealing material 107 made of an epoxy resin, an acrylic resin, or the like is filled in the injection port 106. [0003] The filling of the sealing material 107 utilizes a capillary phenomenon. In addition, a pressure difference or a temperature difference between the internal space and the outside of the panel is provided to promote filling. With the passage of time, the sealing material 107 is
, And is fixed by performing a curing process at the stage of filling. However, the penetration speed of the sealing material 107 varies depending on the individual panel.
As shown in FIG. The liquid crystal filled in the display area 103 is partially filled with the sealing material 107.
Therefore, there is a problem that normal image display cannot be performed and a display defect occurs. As a measure for preventing the sealing material from protruding, for example, a structure in which a bank 108 is provided between the injection port 106 and the display area 103 as shown in FIG. 6 has been proposed. Embankment 108
Is formed at the same time as the printing application of the sealing material 105, for example.
It intervenes over the gap between the upper and lower substrates 101 and 102. The bank 108 has an effect on a small amount of the sealing material 107 protruding, but if it exceeds a certain amount, it enters the display area 103 as shown in the figure. In a small high-definition liquid crystal display panel having a diagonal dimension of 1 inch or less, a space for providing the bank 108 may not be secured. Alternatively, the presence of the bank 108 increases the size of the substrate, which is disadvantageous in cost. SUMMARY OF THE INVENTION In view of the above-mentioned problems of the prior art, an object of the present invention is to effectively suppress the protrusion of a sealing material from a display area of a liquid crystal display panel.
The following measures were taken to achieve this purpose. That is, the liquid crystal display panel according to the present invention has, as a basic configuration, a pair of substrates, a sealant, a liquid crystal, and a sealant. 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 sealant is disposed along the peripheral region and bonds the two substrates together to form an internal space including the display region. An injection port is provided by partially removing the sealing material in advance. The liquid crystal is introduced into the internal space through this inlet to fill the display area. The sealing material is filled into the injection port to complete the hermetic structure of the liquid crystal display panel. As a feature of the present invention, when providing a concave portion for preventing the invasion of the sealing material in at least one of the substrates so as to cross between the injection port and the display region, a groove is formed in the insulating film covering the substrate by photolithography and etching. The recess is provided by patterning. The sealing material filled in the injection port reaches the recess
When it arrives, the recessed part having the groove shape due to the capillary phenomenon
Guided along the edge. According to the present invention, at least one of the substrates is provided with a concave portion so as to cross between the injection port and the display region.
Therefore, the substrate gap size at the injection port is relatively reduced as compared with the substrate gap size of the concave portion. For this reason, the liquid sealing material filled in the injection port cannot move forward from the groove-shaped concave portion due to the effect of surface tension. When filled sealing material having reached the recess, is guided so as to perpendicular to the filling direction along the edge of the recess having a groove shape due to a capillary phenomenon. In other words, the sealing material can not be proceeding from the recess by surface tension, it is not possible to reach the display area. This makes it possible to effectively prevent display defects caused by invasion of the sealing material, which has conventionally been a problem. Preferred embodiments of the present invention will be described below in detail with reference to the accompanying drawings. 1A and 1B show a structure of a liquid crystal display panel according to the present invention, wherein FIG. 1A is a plan view and FIG.
Is a sectional view. As shown in FIG. 1A, an upper glass substrate 1 and a lower glass substrate 2 are arranged to face each other with a predetermined gap therebetween to form a liquid crystal display panel. This panel is divided into a central display area 3 and a peripheral area 4 surrounding it. A sealing material 5 is provided along the peripheral area 4, and the upper and lower substrates 1 and 2 are adhered to each other to form an internal space including the display area 3. The sealing material 5 has been partially removed in advance, and an inlet 6 is provided. Liquid crystal is introduced into the internal space through the injection port 6 to fill the display area 3. Further, a sealing material 7 is filled in the inlet 6 to complete the hermetically 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 concave portion 8 for preventing the intrusion of the sealing material 7 so as to cross between the injection port 6 and the display region 3. . The recess 8 has a groove shape. Referring to FIG. 1A, a method of 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, a sealing material 5 is applied by screen printing or the like along the display area 3 and the peripheral area 4 surrounding the recess 8. The sealing material 5 is made of an ultraviolet curable adhesive or a thermosetting adhesive. Next, the upper glass substrate 1 is overlapped, the sealing material 5 is cured, and the upper and lower substrates 1 and 2 are joined to each other. In addition, when the sealing material 5 is screen-printed, the injection port 6 is formed,
Pattern the screen mask. Next, the inside space including the display area 3 is evacuated to vacuum and the outside of the panel is returned to the atmospheric pressure while the liquid crystal is in contact with 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 inlet 6 by capillary action. 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 inlet 6 receives the surface tension, it cannot exceed the recess 8 and is guided to the side parallel to the groove. This prevents the sealing material 7 from protruding from the display area 3. Finally, the sealing material 7 is cured by irradiating ultraviolet rays to complete the sealing step. Even if the sealing material 7 filled in the inlet 6 is left uncured for a long time, there is no fear that the sealing material 7 will enter the display area 3 beyond the recess 8. Therefore, there is no need to manage the filling time as in the conventional case, and a large number of the units can be cured at once, leading to a streamlining 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 joined to each other by a sealing material 5. The gap between the two substrates 1 and 2 is filled with the liquid crystal 9 as described above, and is sealed by the sealing material 7. The recess 8 described above is formed by a groove formed in the insulating film 10 covering the lower glass substrate 2. The insulating film 10 is made of an ultraviolet curable acrylic resin and has a thickness of about 1 μm. The insulating film 10 is directly exposed and developed to form a groove-shaped concave portion 8 by patterning. Note that the insulating film 10 is not limited to the above-described resin material, and various patternable organic or inorganic materials 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, no extra space is required, and it can be easily provided in a small and high-definition active matrix liquid crystal display panel. Also, there is no need to increase the dimensions of the substrate. The substrate gap size of the liquid crystal display panel is set to, for example, about 5 μm. On the other hand, the thickness of the insulating film 10 is, for example, 1 μm.
m, and the depth of the concave portion 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 recess 8, the sealing material 7 is strongly affected by the surface tension, and does not flow into the inside beyond the recess 8. FIG. 2 is a schematic sectional view showing another embodiment of the liquid crystal display panel according to the present invention. The basic configuration is the same as that of the previous embodiment shown in FIG. 1B, and corresponding portions are denoted by corresponding reference numerals to facilitate understanding. The difference is that a groove is formed directly on the surface of the lower glass substrate 2 to constitute the above-described recess 8. This groove is obtained by, for example, directly etching the glass substrate 2 with hydrofluoric acid or the like. Alternatively, the glass substrate 2
May be ground by half dicing or the like. FIG. 3 is a schematic partial sectional view showing a specific configuration example of the liquid crystal display panel shown in FIG. It should be noted that this specific example is given for explanation, and the present invention is not limited to this. For easy understanding, a central display area and a peripheral area where an injection port is provided are shown separately. In the display region, 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, a thin film transistor 23 for switchingly driving the individual pixel electrodes 22 is also integratedly formed. 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 can open a contact hole by exposure and development processing. The upper pixel electrode 22 and the lower thin film transistor 23 are electrically connected to each other via the contact hole. The opposite substrate 25 is joined to the lower insulating substrate 21 via a predetermined gap. A counter electrode 26 is formed on the inner surface of the counter substrate 25 in advance. Both substrates 21,2
5, the liquid crystal layer 27 is held to form an active matrix type display area. On the other hand, in the peripheral region, the flattening layer 2 made of acrylic resin is formed on the surface of the lower insulating substrate 21.
4 extend. The flattening layer 24 is patterned into a predetermined shape simultaneously with the opening of the contact hole, and a groove-shaped concave portion 28 is provided. By interposing the concave portion 28, the intrusion of the sealing material 29 into the inside can be effectively prevented. FIG. 4 schematically shows a planar shape of the active matrix type liquid crystal display panel shown in FIG. As described above, the pixel electrodes 22 are integrally formed on the lower insulating substrate 21 in a matrix. Correspondingly, a thin film transistor 23 for switching drive is also formed integrally. Also, the gate line 30 extends along the row direction.
Are formed in a pattern, and the signal lines 31 are also formed in a pattern along the column direction. The gate electrode of each thin film transistor 23 has a 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. On the surface of the insulating substrate 21, a vertical drive circuit 32 and a horizontal drive circuit 33 also formed of thin film transistors are formed integrally. The vertical drive circuit 32 has a gate line 3
The thin film transistor 23 is selected line-sequentially for each row via 0. On the other hand, the horizontal drive circuit 33 is connected to the pixel electrode 2 through the selected thin film transistor 23 through the signal line 31.
2 is written with an image signal. Thus, a desired display operation can be performed. The vertical drive circuit 32 and the horizontal drive circuit 33
Is connected to an extraction electrode 34 to establish electrical continuity with the outside. A sealing material 35 is provided along a peripheral area surrounding the display area having such a structure, and joins the lower insulating substrate 21 and the upper counter substrate 25 to each other. A part of the sealing material 35 is cut out to serve as an injection port. As described above, the groove-shaped concave portion 28 is formed by patterning on the surface of the insulating substrate 21 so as to separate the injection port from the display region, thereby preventing the sealing material 29 from entering the inside. 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, so that the inside of the sealing material is formed. There is an effect that intrusion can be prevented. The penetration of the sealing material into the inside is prevented by the effect of the surface tension utilizing the difference in the substrate gap size between the inlet and the recess. Even if left for a long time, the liquid sealing material does not proceed inside, so that time management in the sealing step becomes unnecessary, and the process can be streamlined. Since the groove-shaped concave portion can be formed extremely compact, it can be applied to a liquid crystal display panel having a small size, and cost reduction can be realized by downsizing the outer shape.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic plan view and a sectional view showing one 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 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. [Description of Signs] 1 Substrate 2 Substrate 3 Display area 4 Peripheral area 5 Sealing material 6 Inlet 7 Sealing material 8 Depression 9 Liquid crystal 10 Insulating film

────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-60-67927 (JP, A) JP-A-5-232497 (JP, A) JP-A-2-67523 (JP, A) JP-A-5-1995 281533 (JP, A) JP-A-5-6845 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) G02F 1/1341

Claims (1)

(57) [Claims 1] A pair of substrates which are disposed to face each other with a predetermined gap therebetween and have a display region and a peripheral region surrounding the display region;
A sealing member disposed along the peripheral region and bonding the two substrates to each other to form an internal space including the display region; and an injection port provided by partially removing the sealing material in advance. A concave portion including a liquid crystal introduced into the internal space and a sealing material filled in the injection port, and blocking entry of the sealing material into at least one substrate so as to cross between the injection port and the display region. the liquid crystal display panel provided, the recess, Ri Na <br/> from the groove which is patterned photolithographically and etching the insulating film covering the substrate, the sealing material to the recess which is filled in the infusion inlet When reached, hair
Conducted along the edge of the groove-shaped recess due to capillary action
The liquid crystal display panel, characterized in that Ru him.