JPH09236808A - Production of liquid crystal display panel - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a method for manufacturing a liquid crystal display panel in which vicinity of peripheral parts of a pair of substrates disposed to face each other are joined by sealing and space between substrates inside the sealing is packed with liquid crystal, in particular a manufacturing method in which a pair of substrates are joined at uniform intervals over a whole display region. SOLUTION: A thermosetting type adhesive 3' for sealing and a photosetting type adhesive 4' for a temporarily fastening member are adhered on a surface of the substrate 1. Then, the adhesive 3' for sealing is subjected to a prebaking treatment and the substrate 2 is superposed on the substrate 1 across the adhesive 3' for sealing and the adhesive 4' for the temporarily fastening member. Thereafter the adhesive 4' for the temporarily fastening member is cured while the substrate 2 is pressed toward the substrate 1 so that an adhered part of the adhesive 4' for the temporarily fastening member is pressed more strongly than an adhered part of the adhesive 3' for sealing. The adhesive 3' for sealing is cured while the substrate 2 is pressed toward the substrate 1 to execute a postbaking treatment.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a liquid crystal display panel in which a gap between a pair of substrates is filled with liquid crystal, and more particularly,
The present invention relates to a manufacturing method in which a pair of substrates are bonded at uniform intervals over the entire display area.

In recent years, liquid crystal display panels have been supplied in large quantities to many OA devices and the like, and as demand has greatly increased, it has been desired to supply inexpensive and highly reliable products with improved display quality. ing.

[0003]

2. Description of the Related Art In a liquid crystal display panel, a peripheral portion of a pair of substrates having desired electrode patterns and the like is joined by a seal having a loop pattern, and liquid crystals are filled between the substrates surrounded by the seals.

The gap between the pair of bonded substrates is made uniform by the spherical spacers scattered on the substrates and the fiber-like spacers mixed in the seal. Generally, a thermosetting adhesive is used for the seal. ing.

When the pair of substrates are joined by the seal, the positional relationship between the substrates is accurately determined prior to the joining which requires heat treatment for 1 hour or more, and then a photo-curing adhesive is generally used. Temporary stopping is done.

FIG. 4 is an explanatory view of a substrate bonding method in a conventional liquid crystal display panel, where 1 is a first substrate (glass substrate) on which desired electrodes and the like are formed, and 2 is a desired electrode and the like. Also, a second substrate (glass substrate), 3 is a seal, 4 is a temporary fixing member, and 5 is a liquid crystal.

In FIG. 4 (a), a sealing adhesive 3'which is a thermosetting resin and a temporary fixing member which is a photosetting resin are provided on the surface of the substrate 1 on which the desired electrodes 6 are formed. The adhesive 4 ′ is applied, and a large number of spherical spacers 8 are scattered on the electrodes 6 and the like.

The adhesive 3'containing a solvent for forming a paste that is easy to apply is prebaked after application, for example, 90 ° C., in order to prevent the solvent from being mixed in the liquid crystal 5 and impairing the display quality. Heat treatment is performed at 100 ° C. for about 5 minutes to 10 minutes to remove the solvent, and the substrate 2 is joined after being semi-cured.

In FIG. 4B, a substrate 2 having desired electrodes 7 and the like formed on its lower surface is superposed on the substrate 1, and an appropriate pressing force F, for example, the size of the substrates 1 and 2 is 300 mm × 400 m.
In the case of m, while pressing the substrate 2 against the substrate 1 with a pressing force F of 200 Kg to 500 Kg, the adhesive 4'is irradiated with ultraviolet light UV of an appropriate intensity at room temperature.

As a result, the adhesive 4'is cured and becomes the temporary fixing member 4, and the temporary joining of the substrate 1 and the substrate 2 is performed. Then, as shown in FIG. 4 (c), an appropriate pressing force F '
While pressing the substrate 2 against the substrate 1 with the spacer 8
And post-baking treatment of the adhesive 3'in a state of being in contact with the substrate 2, for example, by heating at 130 ° C to 150 ° C for about 1 to 2 hours, the adhesive 3'softened in the heating process is crushed by the pressing force F '. Then, when the post-baking process is performed to cure the adhesive 3'with the spacer 8 in contact with the substrate 1 and the substrate 2, the cured adhesive 3'becomes the seal 3 and the joining of the substrate 1 and the substrate 2 is completed. .

Therefore, the liquid crystal 5 is filled in the gap between the substrates 1 and 2 surrounded by the seal 3, and unnecessary portions around the substrates 1 and 2 are cut and removed to complete the liquid crystal display panel.

[0012]

In the above-mentioned conventional method of joining the substrate 1 and the substrate 2, the substrate 2 is pressed against the substrate 1 between a surface plate having a smooth upper surface and a surface plate having a smooth lower surface. The substrates 1 and 2 are sandwiched so that the adhesive 3'for sealing is used at the time of curing the adhesive 4'for the temporary fixing member at room temperature.
Is a semi-cured state.

Therefore, when the temporary fixing member 4 and the seal 3 are brought close to each other, the spacer 9 inside the adhesive 3'is formed by the spacer 9 in the adhesive 3'when forming the temporary fixing member 4 which cures the adhesive 4'at room temperature. It is difficult to press the substrate 2 so as to be sandwiched between the two substrates, that is, the pressing force F that crushes the semi-cured adhesive 3 ′ so that the spacer 9 is sandwiched between the substrates 1 and 2 without damaging the substrate 2. It was difficult to add.

Therefore, for example, when the diameter of the spacer 9 is 8 μm, the thickness of the temporary tacking member 4 is about 14 μm, and the thickness of the temporary tacking member 4 interferes with the post-baking of the adhesive 3 ', and the thickness of the seal 3 is disturbed. It is difficult to make the thickness the same as the diameter of the spacer 9 and the display quality in the vicinity of the seal 3 is impaired.

By increasing the distance between the seal 3 and the temporary fixing member 4, the thickness of the seal 3 can be made equal to the diameter of the spacer 9, that is, even if the thickness of the temporary fixing member 4 is about 14 μm. The thickness of the seal 3 is 8 μm, which is the same as the diameter of the spacer 9.
It is possible to set the degree.

However, if the distance between the seal 3 and the temporary fixing member 4 is increased, the substrates 1 and 2 larger than the conventional ones are required, which increases the manufacturing cost of the liquid crystal panel and the panel in the subsequent steps. It becomes troublesome to handle.

[0017]

[Means for Solving the Problems] The purpose of the present invention is to make the seal thickness the same as the spacer diameter in the seal and to secure the display quality in the vicinity of the seal without separating the seal from the temporary fixing member. The present invention relates to a step of depositing a thermosetting adhesive for sealing and a photocurable adhesive for temporary fixing member on the surface of a first substrate, a pre-baking treatment step for the adhesive for sealing, and a step for sealing. A step of stacking a second substrate on the first substrate while sandwiching an adhesive agent and the adhesive agent for the temporary fixing member, and a portion to which the temporary adhesive agent has been applied is applied with the sealing adhesive agent. And pressing the second substrate against the first substrate so that the second substrate is pressed against the first substrate so that the second substrate is pressed against the first substrate so that the second substrate is pressed against the first substrate. Post-baking while curing the sealing adhesive while To comprising the management step, a method of manufacturing a liquid crystal display panel.

In the method of manufacturing the liquid crystal display panel according to the present invention, the part of the substrate corresponding to the temporary adhesive is pressed more strongly than the part corresponding to the sealing adhesive. And
The substrate pressing force of the portion corresponding to the temporary adhesive is stronger than the substrate pressing force in the conventional method, but the pressed substrate absorbs the strong pressing force and is not damaged.

Therefore, the thickness of the temporary tacking member according to the method of the present invention can be made thinner than the thickness of the temporary tacking member in the conventional method, and the seal is sealed with the adhesive for sealing during the next post-baking of the sealing adhesive. It is possible to make the diameter of the spacer the same as that of the spacer, and the display quality of the display panel near the seal can be secured.

[0020]

1 is a perspective view showing the outer appearance of a liquid crystal display panel according to an embodiment of the present invention, FIG. 2 is an explanatory view of main manufacturing steps in the embodiment of the present invention, and FIG. 3 is an embodiment of the present invention. It is explanatory drawing of the pressing tool used for formation of the temporary stop member in the example.

In FIG. 1A, the liquid crystal display panel 11
A pair of substrate 1 and substrate 2, for example, a TFT substrate 1 on which a TFT or the like is formed and a substrate 2 on which a color filter or the like is formed.
Are joined by a seal 12 near the periphery thereof and temporary fixing members 13 provided at four corners. The seal 12 and the temporary fixing member 13 have almost the same thickness, or the thickness of the temporary fixing member 13 is different from that of the seal 12. Is formed to be slightly smaller than the thickness of.

In FIG. 1B, 8 is a substrate 1 and a substrate 2.
Spherical spacers sandwiched between the electrodes, etc. forming surface, 9 is a seal 1
2 is a fibrous spacer in 2, and the spacer 8 is sandwiched between the electrode 6 and the like formed on the upper surface of the substrate 1 and the electrode 7 and the like formed on the lower surface of the substrate 2, and the spacer 9 is formed on the upper surface of the substrate 1. It is in a state of being sandwiched by the lower surface of the substrate 2.

Thus, the seal 12 and the temporary fixing member 1
The substrate 1 and the substrate 2 joined by 3 are filled with the liquid crystal 5 in the space surrounded by the seal 12, and the peripheral unnecessary portions of the substrate 1 and the substrate 2 are cut and removed.
Is completed.

In FIG. 2A, the liquid crystal display panel 11
On the surface of the substrate 1 on which the electrodes 6 are formed in the display area of
A loop-shaped sealing adhesive 3'containing a spacer (generally glass fiber) 9 and a spot-shaped temporary adhesive 4 '
Is applied, and spacers 8 are scattered on the electrodes 6 and the like.

The spacer 8 is of ordinary type, for example, a diameter of 5
A sphere made of plastic with a size of about μm is used.
The adhesive 3'and the adhesive 4'are applied by an ordinary method such as a dispenser or screen printing, and the thermosetting adhesive 4'is prebaked to remove the solvent contained in the adhesive 4 '. It has been removed.

In FIG. 2B, the substrate 2 is overlaid on the substrate 1. At that time, the substrate 2 is accurately positioned with respect to the substrate 1 so that the electrode 7 and the like properly correspond to the electrode 6 and the like.

Next, as shown in FIG. 2 (c), the adhesive 4'is irradiated with ultraviolet light UV of a predetermined intensity in a state where the substrate 2 is pressed against the substrate 1, and the temporary fixing member 13 in which the adhesive 4'is cured. To complete.

At this time, the pressing force F ₁ of the portion to which the adhesive 4'is applied is appropriately stronger than the pressing force F ₂ of the other portions, that is, the thickness of the adhesive 4'is equal to the diameter of the spacer 9. The pressing force F ₁ is the same or slightly reduced. However, the pressing force F ₂ is the pressing force in the conventional method (see FIG. 4).
Equivalent to F.

Then, as shown in FIG. 2 (d), when the post-baking temperature is applied, the adhesive 3'softens and the spacer 9 is sandwiched between the substrate 1 and the substrate 2.
_When the post-baking process of the adhesive 3'is performed while pressing the substrate 2 toward the substrate 1 at 3, the adhesive 3'is cured to form the seal 12, and the bonding between the substrate 1 and the substrate 2 is completed.

In FIG. 3 (a), 21 is a base, 22 is a surface plate whose upper surface is smoothed and which is mounted on the base 21,
Reference numeral 23 is a surface plate whose bottom surface is smoothed, 24 is a shaft for supporting the surface plate 23, and the shaft 24 moves up and down by a hydraulic cylinder or an air cylinder. Press down toward 22.

Protrusions 25 having appropriate flexibility, for example, protrusions 25 to which an acetate film having a thickness of about 40 μm is attached are formed at predetermined portions at the four corners of the rectangular platen 23. In FIG. 3B, the substrate 1 on which the adhesive 3 ′ and the adhesive 4 ′ are adhered and the substrate 2 which is accurately positioned and overlapped on the substrate 1 are mounted on the surface plate 22, and then the surface plate 23 is mounted. Then, the substrate 2 is lowered and a predetermined pressing force is applied toward the substrate 1.

As described with reference to FIG. 1C, the pressing force is such that the thickness of the adhesive 4'is equal to or slightly smaller than the diameter of the adhesive 3'spacer 9 and is bonded with a pressing force F ₁ . agent 4 'presses the deposition unit, the adhesive 3' deposition unit are those pressed by the pressing force F ₁ is smaller than the pressing force F _2, ultraviolet UV to the adhesive 4 'while adding the pressing force Is irradiated, the adhesive 4'is cured and the temporary fixing member 13 is completed.

The convex portion 25 contacting the substrate 2 damages the substrate 2.
This is done because appropriate softness is required to prevent damage.
In the example, acetate film is used and the pressing force F₁Is pressed
Force F _TwoThe thickness of the convex portion 25 in order to make it larger appropriately
Pressing force F_TwoIs the same as the pressing force F in the conventional method.
Then, it is preferable to set the thickness of the convex portion 25 to 40 μm.
Results were obtained.

[0034]

As described above, according to the present invention, in a liquid crystal display panel using a thermosetting adhesive as a sealant and a photocurable adhesive as a temporary fixing member,
It is possible to make the thickness of the temporary stop member equal to or less than the seal thickness without separating the seal and the temporary stop member and damaging the substrate. It is the same as the spacer diameter, and the display quality near the seal can be secured.

[Brief description of drawings]

FIG. 1 is a perspective view showing an appearance of a liquid crystal display panel according to an embodiment of the present invention.

FIG. 2 is an explanatory view of main manufacturing steps in an embodiment of the present invention.

FIG. 3 is an explanatory view of a pressing tool used for forming a temporary fixing member in an example of the present invention.

FIG. 4 is an explanatory view of a substrate bonding method in a conventional liquid crystal display panel.

[Explanation of symbols]

 1, 2 Substrate 3'Adhesive for sealing 4'Adhesive for temporary fixing member 8,9 Spacer 11 Liquid crystal display panel 12 Seal 13 Temporary fixing member

Claims (3)

[Claims] 1. A step of depositing a thermosetting adhesive for sealing and a photocurable adhesive for a temporary fixing member on the surface of a first substrate, a pre-baking treatment step of the adhesive for sealing, and the seal. Stacking the second substrate on the first substrate with the adhesive for adhesive and the adhesive for temporary fixing member sandwiched between the adhesive and the adhesive for sealing. The second part so that it is pressed more strongly than
Curing the temporary adhesive while pressing the first substrate toward the first substrate, and curing the sealing adhesive while pressing the second substrate toward the first substrate. And a post-baking treatment step for allowing the liquid crystal display panel to be manufactured. 2. When the second substrate is pressed toward the first substrate, a convex portion is formed at a corresponding portion of the photocurable adhesive for the temporary fixing member, and a surface plate is used. The method for manufacturing a liquid crystal display panel according to claim 1, wherein the liquid crystal display panel is manufactured. 3. The convex portion abutting on the second substrate,
The method for manufacturing a liquid crystal display panel according to claim 2, wherein the second substrate is formed of a member having flexibility that does not damage the second substrate.