JPH0519268A - Liquid crystal display element - Google Patents

Abstract

PURPOSE:To suppress the peeling of sealing and to improve the reliability and yield of the element by reinforcing at least a part of the outer peripheral part of the sealing with an adhesive. CONSTITUTION:The adhesive 7 is stuck to the outer periphery of the sealing parts of the liquid crystal display element constituted by forming the sealing parts by using a sealant 4 between a pair of transparent substrates 1 and 2 having transparent electrodes on the inner side and sealing a liquid crystal therebetween to intensify the strength of the sealing parts. The adhesive 7 may be stuck to the entire outer periphery or a part thereof in such a case. More particularly preferably the adhesive 7 is recommended to be applied to the part where only the one substrate 2 protrudes to the outer side of the sealing parts since there are taking-out electrodes in the corner parts of the substrates 1 facing each other. The reason thereof lies in that the sealing peels in some cases when force is applied to this projecting part. Then, the effect is higher in the case of use of plastic film substrates with which the strength of the substrates themselves is inferior to glass substrates. The adhesive 7 consists preferably of the same material as the sealant 4.

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 particular, the present invention relates to a liquid crystal display element capable of suppressing peeling of a seal at a seal portion and improving reliability and yield of the element.

[0002]

2. Description of the Related Art In a conventional liquid crystal display element, a liquid crystal display element is formed by simply printing a sealant on the seal portion by screen printing and adhering the periphery of the cell. This type of liquid crystal display element is disclosed in, for example, Japanese Patent Application Laid-Open No. 2-29625. Hereinafter, a specific description will be given with reference to the drawings.

FIG. 5 is a plan view and a schematic sectional view showing the structure of a conventional liquid crystal display element. In FIG. 5, reference numerals 31 and 32 denote transparent substrates, and the transparent substrates 31 and 32 are arranged to face each other with a predetermined space therebetween via a spacer 33. Further, the transparent substrates 31 and 32 around the transparent substrate 31 are disposed. Sealant between
34 are provided. 35 is a liquid crystal filled so as to be surrounded by the sealant 34 and the transparent substrates 31 and 32, and 36
Is a liquid crystal 35 filled in the transparent substrates 31, 32 and the sealant 34.
It is a sealant for sealing.

In a conventional liquid crystal display element, a pair of transparent substrates 31 and 32 each having a transparent electrode formed in a desired pattern are arranged to face each other with a predetermined space therebetween via a spacer 33.
A sealant is applied around the overlapping portion of the pair of transparent substrates 31 and 32.
Both are adhered at 34, liquid crystal 35 is further injected from the injection port, and finally sealed with a sealant 36.

[0005]

However, in the above-mentioned conventional liquid crystal display element, the sealant 34 and the spacer 33 are used.
Since the two transparent substrates 31 and 32 are overlapped with each other through the above, and the extraction electrode portion is usually one transparent substrate 32, it is formed in the vicinity of the extraction electrode in the subsequent manufacturing process or device. In the part at the time of sealing, FIG.
When a force (F ₁ ) is applied as shown by the arrow in FIG.
As shown in (b), the sealant 34 is peeled off from the transparent substrate 32, the liquid crystal 35 flows out, and bubbles are generated inside the element, which lowers the reliability of the element and lowers the yield. there were. In particular, when a plastic film substrate was used, the expansion and contraction of the substrate was large, so that the sealant 34 itself was easily peeled off, and as shown in part A of FIG.

Therefore, an object of the present invention is to provide a liquid crystal display device capable of suppressing peeling of a seal and improving the reliability and yield of the device.

[0007]

According to another aspect of the present invention, there is provided a liquid crystal display device in which a seal portion is formed between a pair of transparent substrates having a transparent electrode inside by using a sealant to seal a liquid crystal. In, at least a part of the outer peripheral portion of the seal is reinforced with an adhesive. According to a second aspect of the invention, in addition to the configuration of the first aspect of the invention, the adhesive is made of the same material as a sealing agent or a sealing agent.

According to a third aspect of the present invention, one of the transparent substrates is projected to the outside of the seal portion, and an adhesive is reinforced from the outside of the seal portion in the vicinity of the seal portion in the non-overlapping portion of the pair of transparent substrates. It will be. Claim 4
In the invention described above, an adhesive is formed so as to sandwich the pair of transparent substrates at the corners of the pair of transparent substrates where the liquid crystal inlets overlap.

According to a fifth aspect of the present invention, in the seal portion,
At least one hole having a diameter smaller than the seal width is provided, and when a pair of transparent substrates are superposed, the adhesive is leached to the upper portions of the pair of transparent substrates and cured.

[0010]

First, the operation of the present invention will be described. In the present invention, first, after forming a transparent conductive film such as In ₂ O ₃ —SnO ₂ (ITO) or SnO ₂ to be a transparent electrode on a transparent substrate, a desired electrode pattern is formed.
The transparent substrate is made of glass, polyether sulfone (P
A plastic film such as ES), polycarbonate (PC), polyethylene terephthalate (PET), or the like can be used. Then, a single-layer or multi-layer thin film having alkali resistance, gas barrier properties, etc. is formed on the substrate as needed.

Next, after forming an overcoat layer such as a color filter layer, a light shielding layer and an insulating layer on the substrate on which the transparent electrode is formed, an alignment film is formed and an alignment treatment represented by rubbing is performed. The overcoat layer may or may not be formed. Next, a sealant is printed on the substrate thus formed, a spacer material for making the cell gap uniform is sprinkled, and the electrodes are overlapped with the electrodes opposed to each other to form a cell before enclosing the liquid crystal.

Next, the liquid crystal is injected from the injection port and the injection port is closed with a sealant to seal the liquid crystal. At the time of injection, if a pressure is mechanically applied from the outside of the substrate and the inside of the cell is depressurized to perform the injection, the cell gap can be made uniform. Next, an adhesive is applied to the outer periphery of the seal portion to increase the mechanical strength of the seal portion. At this time, the adhesive may be applied to the entire outer peripheral portion or only a part thereof. Particularly preferably, since the extraction electrodes are provided at the corner portions of the opposing substrates, the adhesive may be attached to the portion where only one substrate projects outside the seal portion. This is because the seal may peel off when a force is applied to the protruding portion shown in FIGS. When a plastic film substrate is used, the strength of the substrate itself is inferior to that of glass, which is even more effective.

The adhesive may be a sealant or a sealant, but other adhesives may be used. Further, since the adhesive used here does not directly contact the liquid crystal, it is not necessary to consider the characteristics required for the sealant and the sealant such as liquid crystal resistance and gas barrier property. Therefore, it is also possible to use a thermosetting resin adhesive including a natural adhesive, an epoxy adhesive, a thermoplastic resin adhesive, a rubber adhesive, or the like. Further, the step of applying the adhesive may be performed before or after enclosing the liquid crystal, or after attaching the polarizing plate.

Next, the operation of the invention of claim 5
explain. First, In, which becomes a transparent electrode on a transparent substrate,₂O
₃-SnO₂(ITO), SnO ₂Form a transparent conductive film such as
After the formation, a desired electrode pattern is formed. On a transparent substrate
Is glass, polyether sulfone (PES),
Polycarbonate system (PC), polyethylene terephthalate
Use plastic film such as PET (PET)
be able to. And the substrate has alkali resistance and gas
A single-layer or multi-layer thin film with real properties etc.
Form. Then, a color plate is formed on the substrate on which the transparent electrode is formed.
Filter layers, light-shielding layers, insulating layers, etc.
After forming the film, an alignment film is formed and the alignment film typified by rubbing is formed.
Process. Even if the overcoat layer is formed,
Either may be omitted.

Next, a portion where a seal is formed on the substrate,
For example, one or a plurality of holes are formed in a portion where the seal is easily peeled off, such as a corner portion of the cell. The substrate may be opened before the transparent conductive film is formed, after the transparent conductive film is formed, or after the overcoat layer is formed. Next, a sealant is printed on one of the substrates, a spacer for making the cell gap constant is formed on the other substrate, and the substrates are stacked and pressed with a roller or an air bag. At this time, the sealant oozes out from the holes opened in the substrate. Viewed in cross section, since the substrate is limited to the T-type (or the inverted T-type), the sealing strength of the portion opened in the substrate is stronger than the structure in which the sealant is only sandwiched, so that the seal peeling can be prevented. Also, the positions of the holes need not be the same on both substrates, and they may be the same as H
Even if it is a pattern, it does not matter.

Next, the liquid crystal is injected from the injection port and the injection port is closed with a sealant to seal the liquid crystal. At the time of injection, if a pressure is mechanically applied from the outside of the substrate and the inside of the cell is depressurized and injection is performed, the cell gap can be made uniform. The holes that open in the board are used to stack the boards,
After the sealant is cured, a hole smaller than the seal width may be opened, and a sealant, a sealant, another adhesive, or the like may be poured into the hole and fitted therein.

Further, after the polarizing plate is attached, a hole smaller than the seal width may be opened, and a resin such as an adhesive may be poured and fitted in the same manner as described above. The adhesive may be a sealant or a sealant, but a completely different adhesive may be used. Further, since the adhesive used here does not directly contact the liquid crystal, it is not necessary to consider the characteristics required for the sealant and the sealant such as liquid crystal resistance and gas barrier property. Therefore, it is also possible to use a thermosetting resin adhesive including a natural adhesive, an epoxy adhesive, a thermoplastic resin adhesive, a rubber adhesive, or the like. Alternatively, without using an adhesive, the seal portion may be fitted with one or a large number of pins such as metal or resin having a diameter smaller than the seal width. The pin may be used, and it may be before or after the polarizing plate is attached as in the above.

[0018]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to the drawings. FIG. 1 is a plan view and a cross-sectional schematic view showing a configuration of a liquid crystal display element according to an embodiment of the present invention. In FIG. 1, reference numerals 1 and 2 denote transparent substrates, and the transparent substrates 1 and 2 are arranged to face each other with a spacer 3 interposed therebetween. Further, the transparent substrates 1 and 2 around the transparent substrate 1 are disposed. A sealant 4 is provided between them. Further, 5 is a liquid crystal filled so as to be surrounded by the sealant 4 and the transparent substrates 1 and 2, and 6 is a seal for sealing the liquid crystal 5 filled in the transparent substrates 1 and 2 and the sealant 4. It is an agent. An adhesive 7 is formed so as to reinforce a part of the outer peripheral portion of the seal.

Next, a method of manufacturing the liquid crystal display device will be described. PES substrates 1 and 2 on which a gas barrier film is formed
An ITO film is formed on 640 lines on one substrate and on the other
After forming a pattern of 480 stripes and forming an alignment film of polyamide resin, a rubbing process is performed, one substrate is printed with a sealant, and the other substrate is sprinkled with spacers 3 for bonding. Then, the liquid crystal 5 is injected from the injection port and sealed. The liquid crystal 5 remaining on the cell surface is washed to once prepare a liquid crystal cell, and thereafter, an adhesive 7 made of an epoxy resin is attached to the four corners of the cell as in the area A of FIG. 1 (a). At this time, as shown in FIG.
The upper and lower substrates 1 and 2 are sandwiched.

As described above, in this embodiment, since the corner portion of the cell where the seal is easily peeled off is reinforced with the adhesive 7, the peeling of the seal at the corner portion of the cell can be suppressed. Therefore, the reliability and yield of the device can be improved. Although the adhesive 7 made of an epoxy resin is used in the present embodiment, the present invention is not limited to this, and a material used for a sealing agent or a sealing agent may be used for the adhesive 7. .

In this embodiment, the adhesive 7 is applied only to a part of the outer peripheral portion of the seal, but it may be applied to the entire outer peripheral portion of the seal. In this embodiment, the adhesive 7 is applied after the liquid crystal 5 is filled, but the adhesive 7 may be applied after the substrates 1 and 2 are superposed, and in this case, the seal peeling can be prevented before the injection.

Regarding the ITO pattern, 640
The number of lines may not be 480 × 480, and may be appropriately configured in various patterns. The substrate is not limited to the PES substrate and may be another plastic film substrate or a glass substrate. Next, in the present invention, a liquid crystal display element may be formed and configured as follows.

First, an ITO film is formed on a PET substrate,
After forming 640 stripe patterns on one substrate and 480 stripe patterns on the other substrate, an alignment film of polyamide resin is formed. Then, a rubbing process is performed, spacers are scattered on one substrate, and a sealant is printed on the other substrate. When printing this sealing agent, the sealing agent is increased only in the corners so that the sealing agent will protrude from the substrate when superposed. By curing the sealant in this manner, the process shown in FIG.
Similar to the above-described embodiment shown in (b), the upper and lower substrates can be sandwiched. Then, by enclosing the liquid crystal thereafter to fabricate the liquid crystal display element, the same effect as that of the above-described embodiment can be obtained. Further, similar to the above-described embodiment, the shape of the pattern and the type of the substrate may be within the scope of the gist of the present invention.

Next, in the present invention, a liquid crystal display element may be formed as follows. First, an ITO film is formed on a PET substrate, 640 stripe patterns are formed on one substrate, and 480 stripe patterns are formed on the other substrate, and then a polyamide resin alignment film is formed. Next, a rubbing process is performed, spacers are scattered on one substrate, and a sealant is printed on the other substrate and bonded. Then, liquid crystal is injected through the injection port, and the sealant is applied as shown in FIG.
As shown in (b), the upper and lower substrates are attached so as to be sandwiched, and the liquid crystal is sealed by sealing. In this case, the same effect as that of the above embodiment shown in FIG. 1 can be obtained. Further, similar to the above-described embodiment, the shape of the pattern and the type of the substrate may be within the scope of the gist of the present invention.

Next, in the present invention, a liquid crystal display element may be formed and constructed as follows. Here, Figs.
Will be explained. An ITO film is formed on the PES substrates 1 and 2 on which the gas barrier film is formed, and a stripe pattern of 640 lines is formed on one substrate and 480 lines is formed on the other side.
Form a 40 x 480 dot pattern. Then, a hole of 1 mmΦ is formed in the sealed portion of both the substrates 1 and 2. The place to make a hole is as shown in B part of FIGS.
Use the four corners where the seal peels easily. Next, FIG.
As shown in (a) and (b), an alignment film of polyamide resin is formed and subjected to rubbing treatment, and thermosetting epoxy resin is applied to one of the substrates 1 and fine powder of SiO ₂ and Ti ₂ O _{3 is used as} a filler. Print the mixed sealant 4 on the other substrate 2
Spacers 3 are sprinkled on the substrates and the substrates 1 and 2 are attached to each other.
The width of the seal after bonding will be 1.8 mm to 2.5 mm,
The sealant 4 seeps out from the holes made in the substrates 1 and 2,
It spreads from mm to 2.5 mm and hardens by sandwiching the substrates 1 and 2. Finally, the liquid crystal 5 is injected from the injection port, and the liquid crystal 5 is sealed by closing the injection port with the sealant 6 (Fig. 3) (Fig. 4 (c)-
(D)). Here, the holes are opened in a square shape, but it is also possible to form holes at several places as necessary or to open them in non-corner portions to prevent peeling of the seal. The sealing agent 4 is not limited to the above-mentioned one, and may be one that uses an ultraviolet curable type or one that uses another resin.

Next, in the present invention, a liquid crystal display element may be formed as follows. I on the PET substrate
A TO film is formed and 640 × 4 is formed by forming a stripe pattern of 640 on one substrate and 480 on the other substrate.
Form a pattern of 80 dots. Next, an alignment film of polyimide resin is formed, a rubbing process is performed, a sealant is printed on one substrate, and then spacers are sprinkled and bonded to the other substrate. Then, liquid crystal is injected from the injection port and sealed, and the liquid crystal remaining on the cell surface is washed to produce a liquid crystal cell. After that, a 1 mmΦ hole is opened at the corner of the cell, and epoxy resin is applied to the opened hole. To fill. Then, the epoxy resin is cured so that the upper and lower substrates 1 and 2 are sandwiched (FIG. 4C). In this way, peeling of the seal at the corners of the cell can be prevented. The same resin as the sealant can be used as the epoxy resin.
Alternatively, the polarizing plate may be attached and then opened to fill the resin. In this embodiment, the opening is made after the liquid crystal is injected, but it is also possible to make the opening before the injection of the liquid crystal to cure the resin and then to fill the liquid crystal.

Next, in the present invention, a liquid crystal display element may be formed as follows. I on the PET substrate
A TO film is formed and a stripe pattern of 640 on one substrate and 400 on the other substrate is formed.
Form a pattern of 00 dots. Next, an alignment film of polyimide resin is formed, a rubbing process is performed, one substrate is printed with a sealant, and the other substrate is sprinkled with spacers and bonded. The seal width at this time is from 1.8 mm
It will be 2.5 mm. Then, liquid crystal is injected from the injection port to seal it, and the liquid crystal remaining on the surface of the cell is washed to produce a liquid crystal cell, and then a corner of the cell with a diameter smaller than the seal width from 0.6 mm to 1.5 mm Mated with mm pin. The pin reinforces the seal and prevents peeling of the seal.

[0028]

According to the present invention, it is possible to suppress peeling of the seal and improve the reliability and yield of the device.

[Brief description of drawings]

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

2A and 2B are schematic plan and sectional views showing the configuration of a liquid crystal display device applicable to the present invention.

FIG. 3 is a schematic plan view showing a configuration of a liquid crystal display element applicable to the present invention.

FIG. 4 is a diagram illustrating a method of manufacturing a liquid crystal display element applicable to the present invention.

5A and 5B are a plan view and a cross-sectional schematic view showing a configuration of a liquid crystal display element of a conventional example.

FIG. 6 is a diagram illustrating a problem of a conventional example.

[Explanation of symbols]

1 transparent substrate 2 transparent substrate 3 spacers 4 Sealant 5 liquid crystal 6 Sealant 7 adhesive

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor San-ichi Sakurai             1-3-3 Nakamagome, Ota-ku, Tokyo Stocks             Company Ricoh (72) Inventor Yumi Matsuki             1-3-3 Nakamagome, Ota-ku, Tokyo Stocks             Company Ricoh

Claims (5)

[Claims] 1. In a liquid crystal display device in which a sealant is formed between a pair of transparent substrates having a transparent electrode inside and a liquid crystal is sealed, at least a part of the outer periphery of the seal is reinforced with an adhesive. Liquid crystal display device characterized by. 2. The liquid crystal display element according to claim 1, wherein the adhesive is made of the same material as a sealing agent or a sealing agent. 3. One of the transparent substrates is projected outward from a seal portion, and an adhesive is reinforced from the outside of the seal portion in the vicinity of the seal portion in a portion where a pair of transparent substrates do not overlap each other. The liquid crystal display element according to claim 1 or 2. 4. An adhesive is formed at a corner portion of a pair of transparent substrates where the liquid crystal injection ports overlap with each other so as to sandwich the pair of transparent substrates.
3. The liquid crystal display device according to any one of items 1 to 2. 5. The seal portion is provided with at least one hole having a diameter smaller than the seal width, and when a pair of transparent substrates are superposed, the adhesive is leached to the upper portions of the pair of transparent substrates and cured. The liquid crystal display device according to claim 1, wherein the liquid crystal display device is formed by: