JP2000330122A - Production of liquid crystal display device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for the production of a liquid crystal display device by which the hardening state of a sealing resin by UV rays used to bond a pair of transparent substrates as well as to seal a liquid crystal in a liquid crystal panel can be easily checked in the production process and occurrence of failures due to an unhardened part of the sealing resin or decrease in yield can be prevented. SOLUTION: A peeling film 3 and a base film 5 which can be visually distinguished from the peeling film 3 are formed on each of an upper transparent substrate 1 and a lower transparent substrate 2 having the same form as transparent substrates which constitute a product (liquid crystal panel). Then a UV- curing sealing resin 4 is applied and the substrates are laminated and irradiated with UV rays in the same process as the production process of the liquid crystal panel, and then the upper transparent substrate 1 is peeled from the lower transparent substrate 2 and observed. This inspection is carried out periodically and prior to the production of liquid crystal panels.

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.

[0002]

2. Description of the Related Art A liquid crystal panel constituting a liquid crystal display device is composed of:
At least one of the pair of transparent substrates on which a display electrode is formed is provided with a spacer on one side, and the other is coated with a UV-curable sealing resin on the periphery of the substrate,
The pair of transparent substrates are overlapped, and the seal resin is irradiated with ultraviolet light under pressure to be cured, thereby bonding the pair of transparent substrates and injecting a liquid crystal between the bonded pair of transparent substrates. Manufactured. Conventionally, as an inspection method for confirming whether a predetermined amount of ultraviolet light has been irradiated and cured on the sealing resin, the amount of ultraviolet light to be irradiated is measured using an ultraviolet illuminance measuring device, or the ultraviolet light path of the ultraviolet irradiation device and The inspection was performed by visually inspecting the transparent platen to be superimposed.

[0003]

In a liquid crystal display device, when a pair of transparent substrates are opposed to each other and bonded together, and an uncured portion is formed in a sealing resin for enclosing the liquid crystal, the sealing is incomplete and the sealing portion is incomplete. Leakage of the liquid crystal injected in a later step may occur, or uncured sealing resin components may elute into the liquid crystal and contaminate the liquid crystal, which may reduce the reliability and yield of the liquid crystal display device. Conventionally, the cured state of the seal resin is confirmed by the above-described method. In the method of measuring with a UV illuminance measuring device, the average UV irradiation amount in a wide range can be confirmed, but the foreign matter present locally exists. For example, there is a problem that it is not possible to detect the occurrence of an uncured portion of the seal resin due to the shielding of the ultraviolet light by the above-described method. In addition, in the visual inspection, it is possible to detect an uncured portion of the seal resin without leaking due to a detection error that misses an abnormality or a light-blocking foreign material, or a distortion of an ultraviolet light path due to a scratch on a transparent surface plate that cannot be visually detected. There was a problem that it was not possible.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and it is possible to easily confirm the cured state of a sealing resin for sealing a liquid crystal by ultraviolet rays in a manufacturing process by bonding a pair of transparent substrates. It is another object of the present invention to provide a method of manufacturing a liquid crystal display device that can prevent the occurrence of a defect and a decrease in yield due to an uncured portion of a sealing resin.

[0005]

According to a method of manufacturing a liquid crystal display device according to the present invention, a pair of transparent substrates having at least one of them on which a display electrode is formed are opposed to each other and adhered to each other. In a method of manufacturing a liquid crystal display device having an ultraviolet-curable sealing resin for sealing liquid crystal sandwiched between substrates, a peeling film is formed on one of a pair of inspection transparent substrates each having the same shape as the pair of transparent substrates. The step of forming, the step of applying an ultraviolet-curable sealing resin to one of the pair of transparent substrates for inspection, and the pair of transparent substrates for inspection are laminated via the ultraviolet-curable sealing resin,
It includes a step of irradiating ultraviolet rays to cure the ultraviolet-curable seal resin, and a step of peeling off and observing the pair of transparent substrates for inspection. Further, the peeling film is formed of a film which is adhered to the cured portion of the ultraviolet-curable seal resin and peeled off, and does not adhere to the uncured portion of the ultraviolet-curable seal resin. In addition, a base film having a film quality that is visually distinguishable from the peeling film is formed below the peeling film. The peeling film is colored so that it can be visually identified on the inspection transparent substrate. In addition, the method includes a step of performing a physical treatment such as rubbing the region where the ultraviolet-curable seal resin is formed after the pair of inspection transparent substrates is peeled off. Also,
After the pair of transparent substrates for inspection are peeled off, the cured portion of the ultraviolet-curable seal resin is not dissolved, and the uncured portion is washed with a dissolving chemical. The inspection process is performed before the actual product is put into the process and periodically.

[0006]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiment 1 Hereinafter, a method for manufacturing a liquid crystal display device according to an embodiment of the present invention will be described with reference to the drawings. 1, 2 and 3 show Embodiment 1 of the present invention.
FIG. 1 is a view for explaining a method of confirming a cured state of a sealing resin in the production of a liquid crystal display device according to the present invention. FIG. 1 shows a pair of transparent substrates for inspection having the same shape as a liquid crystal panel used for inspecting the cured state of a sealing resin. FIG. 2 is a schematic view showing an ultraviolet irradiation step, and FIG. 3 is a view for explaining a method for inspecting the cured state of the sealing resin.

In the drawing, 1 is an upper transparent substrate of a pair of transparent substrates for inspection having the same shape as the liquid crystal panel, and 2 is a lower transparent substrate of a pair of transparent substrates for inspection having the same shape as the liquid crystal panel. Reference numeral 3 denotes a peeling film formed on the upper transparent substrate 1, for example, a polyimide resin film or the like. 4 is an ultraviolet-curable sealing resin (hereinafter referred to as a sealing resin), 5
Is a base film formed below the release film 3 on the upper transparent substrate 1 and is constituted by a film that can be visually distinguished from the release film 3. For example, ITO (Indium Tin Oxid) which is a transparent conductive film
e) is used. Reference numeral 6 denotes a peeling portion of the peeling film 3 which is adhered to the cured sealing resin 4 and peeled off. 7 is an ultraviolet lamp, 8 is ultraviolet light emitted from the ultraviolet lamp 7, 9, 1
Reference numeral 0 denotes an upper surface plate and a lower transparent surface plate used when irradiating the superimposed upper transparent substrate 1 and lower transparent substrate 2 with ultraviolet light 8, and the ultraviolet light 8 is irradiated from the lower transparent surface plate 10 side. . Numeral 11 is a light source for shielding the ultraviolet light 8 radiated to the sealing resin 4 from light.
This is a foreign substance that has adhered to 0. Reference numeral 12 denotes a sealing resin which is in an uncured state after the irradiation step of the ultraviolet light 8.

Next, a method of manufacturing the liquid crystal display according to the present embodiment will be described. First, in a manufacturing process of a liquid crystal panel of a liquid crystal display device, at least one of a pair of transparent substrates on which a display electrode is formed is overlapped via an ultraviolet-curable sealing resin, and irradiated with ultraviolet light to seal. In the step of curing the resin, a pair of transparent substrates for inspection (upper transparent substrate 1 and lower transparent substrate 2) having the same shape as the transparent substrate constituting the liquid crystal panel are prepared,
After a base film 5 and a peeling film 3 are formed on one transparent substrate, for example, an upper transparent substrate 1, the lower transparent substrate 2 is overlapped with a lower transparent substrate 2 via a sealing resin 4, and ultraviolet rays 8 are irradiated from the lower transparent substrate 2 side. To cure the sealing resin 4 (FIG. 1)
(A)).

Next, after irradiating a predetermined amount of ultraviolet rays 8 to the sealing resin 4, the upper transparent substrate 1 and the lower transparent substrate 2 are peeled off as shown in FIG. At this time, the upper transparent substrate 1
Since the peeling film 3 is formed on the lower transparent substrate 2, the cured sealing resin 4 and the peeled portion 6 of the peeling film 3 at the portion bonded to the sealing resin 4 are fixed to the lower transparent substrate 2 side. In the above, a portion where the peeling film 3 remains and the sealing resin 4 where the peeling film 3 is hardened are adhered and peeled, and a portion where the base film 5 is exposed occurs. Note that since the base film 5 is a film that can be visually distinguished from the peeling film 3, and in this embodiment, an ITO film is used, the seal resin 4 is cured, and the peeling film 3 is peeled off to expose the base film 5. The portion where the peeling film 3 is left and the portion where the peeling film 3 remains can be easily distinguished visually by the difference in the color of the reflected light.

As shown in FIG. 2, when the sealing resin 4 is irradiated with the ultraviolet light 8 and a foreign substance 11 for shielding the ultraviolet light 8 is adhered to the lower transparent platen 10, the sealing resin 4 in that portion is not exposed. Is not irradiated with a predetermined amount of ultraviolet light 8 and becomes uncured. When the upper transparent substrate 1 and the lower transparent substrate 2 are peeled off after being irradiated with the ultraviolet light 8, the peeling film 3 is hardened in the application region of the seal resin 4 on the upper transparent substrate 1 as shown in FIG. The portion where the base film 5 is exposed by being adhered to and peeled off from the seal resin 4 and the portion where the uncured seal resin 12 is adhered on the peeling film 3 can be visually distinguished. Further, in the lower transparent substrate 2, as shown in FIG. 3B, in the application region of the sealing resin 4, there is a peeling portion 6 of the peeling film 3 peeled off by being bonded to the cured sealing resin 4. The part and the part to which the uncured sealing resin 12 is attached can be visually identified.

According to the present embodiment, the transparent substrate constituting the product (liquid crystal panel) has the same shape, and one of the substrates has a base film 5 and a release film that can be visually distinguished from the release film 3. A pair of inspection transparent substrates (upper transparent substrate 1 and lower transparent substrate 2) on which 3 is formed are prepared, and the sealing resin 4 is applied and superposed and irradiated with ultraviolet rays 8 in the same process as the production of the liquid crystal panel. Then, by peeling and observing the upper transparent substrate 1 and the lower transparent substrate 2, the presence of the uncured portion of the sealing resin 4 can be easily visually identified, and the failure due to the uncured portion of the sealing resin 4 can be determined. Generation and reduction in yield can be prevented. In addition, by performing the above-described inspection before and during product introduction into the same process, it is possible to detect the occurrence of uncured portions in the seal resin 4 due to foreign substances brought in during the process. Mass production of non-defective products can be prevented.

Embodiment 2 FIG. In the first embodiment, the base film 5 and the peeling film 3 are formed on the upper transparent substrate 1. However, as shown in FIG. 4, the upper transparent substrate 1 having only the peeling film 13 colored with a pigment or the like is used. Also according to the first embodiment
The same effect can be obtained. FIG. 4 is a cross-sectional view showing a pair of inspection transparent substrates having the same shape as a liquid crystal panel used for inspecting a cured state of a sealing resin according to Embodiment 2, FIG. 5 is a schematic view showing an ultraviolet irradiation step, and FIG. FIG. 4 is a diagram for explaining a method of inspecting a cured state of a seal resin.
In the figure, reference numeral 13 denotes a peeling film colored by a pigment or the like.
For example, a film made of polyvinyl alcohol colored with a pigment is used. Reference numeral 14 denotes a peeling portion of the peeling film 13 which is adhered to the cured seal resin 4 and peeled off. The other configuration is the same as that of the first embodiment, and the description is omitted.

Next, a method of manufacturing the liquid crystal display according to the present embodiment will be described. A pair of inspection transparent substrates (upper transparent substrate 1 and lower transparent substrate 2) having the same shape as the transparent substrate constituting the liquid crystal panel and having a peeling film 13 formed on one (upper transparent substrate 1) are prepared. Then, after irradiating the sealing resin 4 with a predetermined amount of ultraviolet light 8 as in the first embodiment, the upper transparent substrate 1 and the lower transparent substrate 2 are peeled off as shown in FIG. The peeling upper transparent substrate 1 has a peeling film 1
3, the cured sealing resin 4 and the peeling portion 14 of the peeling film 13 adhered to and peeled from the sealing resin 4 are fixed to the lower transparent substrate 2 side, and in the upper transparent substrate 1,
There is a portion where the peeling film 13 remains and a portion where the peeling film 13 is peeled off. Since the peeling film 13 is a film colored with a pigment or the like, a portion where the sealing resin 4 is cured and the peeling film 13 is peeled off and a portion where the peeling film 13 remains are visually observed. Can be easily identified.

As shown in FIG. 5, when the sealing resin 4 is irradiated with the ultraviolet light 8, if a foreign substance 11 that shields the ultraviolet light 8 adheres to the lower transparent platen 10, the sealing resin 4 in that part is removed. Is not irradiated with a predetermined amount of ultraviolet light 8 and becomes uncured. When the upper transparent substrate 1 and the lower transparent substrate 2 are peeled off after being irradiated with the ultraviolet light 8, the peeling film 13 is hardened in the application region of the seal resin 4 on the upper transparent substrate 1 as shown in FIG. A portion that has been peeled off by bonding to the peeled seal resin 4 and an uncured seal resin 12 on the peeling film 13.
The portion to which is attached can be visually identified. In the lower transparent substrate 2, as shown in FIG. 6B, in the application region of the sealing resin 4, there is a peeling portion 14 of the peeling film 13 that is peeled off by being bonded to the cured sealing resin 4. The part and the part to which the uncured sealing resin 12 is attached can be visually identified.

Embodiment 3 FIG. 7 is a diagram for explaining a method of inspecting a cured state of a seal resin according to Embodiment 3 of the present invention. In the figure, reference numeral 15 denotes an uncured portion of the seal resin diffused by a physical process such as a brush process.
Note that the other configuration is the same as that of the first or second embodiment, and a description thereof will be omitted. In this embodiment, the lower transparent substrate 2 as shown in FIG. 3B or FIG. 6B which is formed and peeled by the same method as in the first or second embodiment is used, and the sealing resin 4 is used. Is rubbed with a brush or the like. The portion where the sealing resin 4 is cured by the irradiation of the ultraviolet rays is not removed by rubbing with a brush, but the uncured portion 15 of the sealing resin is diffused by rubbing with a brush.

According to the present embodiment, the lower transparent substrate 2 formed and peeled in the same manner as in the first or second embodiment is sealed by applying a physical force such as rubbing with a brush. Identification of the uncured portion of the resin can be made easier.

Embodiment 4 In the third embodiment, the separated lower transparent substrate 2 is subjected to a physical treatment such as rubbing with a brush. However, as shown in FIG. 8, the separated lower transparent substrate 2 is formed using a chemical such as an organic solvent. The same effect as in the third embodiment can be obtained by dissolving only the uncured seal resin after washing. FIG. 8 is a diagram for explaining a method for inspecting a cured state of a seal resin according to Embodiment 4 of the present invention. In the figure, reference numeral 16 denotes an uncured portion of the sealing resin dissolved and removed by washing using a chemical such as an organic solvent. Note that other configurations are the same as those in the first or second embodiment.
Therefore, the description is omitted.

In the present embodiment, FIG. 3 is formed and peeled by the same method as in the first or second embodiment.
(B) or lower transparent substrate 2 as shown in FIG.
Then, the region where the seal resin 4 is formed is cleaned using a chemical such as an organic solvent (for example, acetone). The portion where the seal resin 4 is cured by the irradiation of the ultraviolet rays is not dissolved by washing with an organic solvent or the like, but the uncured portion 16 of the seal resin is dissolved and removed by washing with an organic solvent or the like. Note that the release films 3 and 1 in the first or second embodiment are used.
By using a solvent that does not dissolve 3, the films 3 and 13 for peeling can be left.

[0019]

As described above, according to the present invention, a predetermined film is formed on an inspection transparent substrate having the same shape as that of a transparent substrate constituting a product (liquid crystal panel), and the same process as that for manufacturing the liquid crystal panel is performed. After applying and irradiating an ultraviolet-curable sealing resin and irradiating with ultraviolet rays, the pair of inspection transparent substrates is peeled off and observed, so that the presence of an uncured portion of the sealing resin can be easily visually identified. Therefore, a defect due to an uncured portion of the seal resin can be efficiently detected, and the yield of the liquid crystal display device can be improved. In addition, by conducting the above-mentioned inspection before and during product launch into the same process,
The occurrence of uncured portions of the sealing resin due to foreign substances brought in during the process can also be detected, and the occurrence of a large number of defective products due to the uncured sealing resin can be prevented.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view showing a pair of transparent substrates for inspection used for inspecting a cured state of a sealing resin in manufacturing a liquid crystal display device according to Embodiment 1 of the present invention.

FIG. 2 is a schematic view showing a step of irradiating a sealing resin with ultraviolet rays in manufacturing the liquid crystal display device according to Embodiment 1 of the present invention.

FIG. 3 is a diagram for explaining a method for inspecting a cured state of a seal resin according to the first embodiment of the present invention.

FIG. 4 is a cross-sectional view showing a pair of transparent substrates for inspection used for inspecting a cured state of a sealing resin in manufacturing a liquid crystal display device according to Embodiment 2 of the present invention.

FIG. 5 is a schematic view showing a step of irradiating a sealing resin with ultraviolet rays in manufacturing a liquid crystal display device according to Embodiment 2 of the present invention.

FIG. 6 is a view for explaining a method for inspecting a cured state of a sealing resin according to a second embodiment of the present invention.

FIG. 7 is a diagram for explaining a method for inspecting a cured state of a sealing resin according to a third embodiment of the present invention.

FIG. 8 is a diagram for explaining a method for inspecting a cured state of a seal resin according to a fourth embodiment of the present invention.

[Explanation of symbols]

1 upper transparent substrate, 2 lower transparent substrate, 3 release film,
4 UV-curable seal resin, 5 base film, 6 peeling part, 7 UV lamp, 8 UV, 9 upper surface plate, 1
0 lower transparent surface plate, 11 foreign matter, 12 seal resin in an uncured state, 13 peeling film, 14 peeling part, 1
5, 16 Uncured part of seal resin.

Claims (7)

[Claims] 1. An ultraviolet-curing type in which a pair of transparent substrates on each of which a display electrode is formed are opposed to and bonded to at least one of them, and a liquid crystal sandwiched between the pair of transparent substrates is sealed. In a method for manufacturing a liquid crystal display device having a sealing resin, a step of forming a peeling film on one of a pair of inspection transparent substrates each having the same shape as the pair of transparent substrates, and any one of the pair of inspection transparent substrates A step of applying the ultraviolet-curable sealing resin to one of them, and the pair of inspection transparent substrates are overlapped with each other via the ultraviolet-curable sealing resin,
A method for manufacturing a liquid crystal display device, comprising: a step of irradiating ultraviolet rays to cure the ultraviolet-curable sealing resin; and a step of peeling off and observing the pair of transparent substrates for inspection. 2. The peeling film is formed of a film which is adhered to a cured portion of the UV-curable sealing resin and peeled off, and does not adhere to an uncured portion of the UV-curable sealing resin. Item 2. The method for manufacturing a liquid crystal display device according to Item 1. 3. The method for manufacturing a liquid crystal display device according to claim 2, wherein a base film having a film quality that is visually distinguishable from the peeling film is formed under the peeling film. . 4. The method according to claim 2, wherein the peeling film is colored so as to be visually distinguishable on the inspection transparent substrate. 5. After peeling off a pair of transparent substrates for inspection,
The method for manufacturing a liquid crystal display device according to any one of claims 1 to 4, further comprising a step of performing a physical treatment such as rubbing on a region where the ultraviolet-curable seal resin is formed. 6. After peeling off a pair of transparent substrates for inspection,
The method for manufacturing a liquid crystal display device according to any one of claims 1 to 4, further comprising a step of washing a cured portion of the ultraviolet-curable seal resin with a solution that does not dissolve and an uncured portion with a soluble chemical. 7. The inspection process according to claim 1, wherein the inspection process is performed before the actual product is put into the process and periodically.
7. The method for manufacturing a liquid crystal display device according to any one of claims 6 to 6.