JP2004309571A - Manufacturing method of liquid crystal display - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent occurrence of a dropping trace of a liquid crystal in a manufacturing method of a liquid crystal display. <P>SOLUTION: The manufacturing method of the liquid crystal display wherein the liquid crystal is encapsulated between a TFT substrate 3 as a driving element substrate and a color filter substrate 2 comprises a dropping step for dropping the liquid crystal on one surface of the color filter substrate 2 and a sticking step for superposing and sticking the color filter substrate 2 and the TFT substrate 3 on which the liquid crystal is not dropped to each other after the dropping step. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a method for manufacturing a liquid crystal display device in which liquid crystal is sealed by dropping liquid crystal on one of two substrates and bonding the substrate to the other substrate.
[0002]
[Prior art]
Conventionally, in order to manufacture a liquid crystal display device, it is necessary to obtain a structure in which liquid crystal is sealed between two glass substrates. As a method for this, as described in Japanese Patent Publication No. Hei 8-20627 (Patent Document 1), a sealant is arranged in a rectangular frame shape on the surface of one of two substrates, and There has been known a technique in which liquid crystal is dropped on the inside, the liquid crystal is bonded to the other substrate, and a sealant is solidified. This method is generally referred to as a "dropping method", as distinguished from an "injection method" in which liquid crystals are injected from an injection port provided in a sealant after the substrates are bonded to each other. In addition to the dropping method, there is a technique disclosed in Japanese Patent Application Laid-Open No. 2002-107740 (Patent Document 2) as a technique for optimizing the amount of liquid crystal to be dropped to prevent the occurrence of a defect.
[0003]
Further, as described in Japanese Patent Application Laid-Open No. 2001-117105 (Patent Document 3), there is also a technique in which liquid crystal is dropped on both of two substrates, and the liquid crystal dropping surfaces are opposed to each other and bonded.
[0004]
[Patent Document 1]
Japanese Patent Publication No. Hei 8-20627
[Patent Document 2]
JP 2002-107740 A
[Patent Document 3]
JP 2001-117105 A
[Problems to be solved by the invention]
In the case of performing the dropping method as described above, when a lighting inspection is performed after a structure in which liquid crystal is sealed by bonding two substrates together, a trace of liquid crystal dropped (hereinafter, referred to as a “drop trace”). Occasionally observed. Such a drop mark should not be present in a liquid crystal display device.
[0008]
Then, an object of the present invention is to provide a manufacturing method of a liquid crystal display device which can prevent a drop mark from occurring.
[0009]
[Means for Solving the Problems]
In order to achieve the above object, a method of manufacturing a liquid crystal display device according to the present invention is a method of manufacturing a liquid crystal display device by enclosing liquid crystal between a driving element substrate and a color filter substrate, comprising: A dropping step of dropping liquid crystal on one surface of the substrate; and a bonding step of stacking and bonding the color filter substrate and the driving element substrate not dropping liquid crystal after the dropping step. By adopting this method, the drop of liquid crystal is not performed on the driving element substrate but only on one surface of the color filter substrate, so that it is possible to prevent the formation of the drop mark.
[0010]
In the above invention, preferably, before the laminating step, a sealing agent disposing step of forming a frame shape of a photocurable resin as a sealing agent on one of the driving element substrate and the color filter substrate, and the laminating step Irradiating light from the side of the color filter substrate to cure the photocurable resin. By employing this method, irradiation is performed from the side of the color filter substrate, so that the sealing agent can be cured without shielding the irradiation light by wiring or the like.
[0011]
Preferably, in the above invention, the laminating step is performed by stacking the driving element substrate from above the color filter substrate. By employing this method, the bonding step can be performed without moving the color filter substrate after dropping the liquid crystal.
[0012]
Preferably, in the above invention, the laminating step is performed by stacking the color filter substrate, the surface of which the liquid crystal is dropped on the lower side, on the upper side of the driving element substrate. By adopting this method, since the color filter substrate is already on the upper side when the laminating step is completed, light irradiation for curing the sealant can be performed from the upper side as it is.
[0013]
BEST MODE FOR CARRYING OUT THE INVENTION
(substrate)
First, the structures of a color filter substrate and a TFT (Thin Film Transistor) substrate commonly used in each embodiment according to the present invention will be described.
[0014]
As shown in FIG. 1, the color filter substrate 2 has a structure in which a color filter layer 21, a counter electrode 22, and a polyimide alignment film 23 are stacked and arranged in this order on a glass substrate 20. On the other hand, in the TFT substrate 3, as shown in FIG. 2, a TFT element 32 as a driving element and an ITO (Indium-Tin Oxide) transparent pixel electrode 31 are regularly and repeatedly arranged on the upper surface of a glass substrate 30. The upper side is covered with an insulating layer 33, and a polyimide alignment film 34 is further disposed on the upper side.
[0015]
(Embodiment 1)
(Production method)
With reference to FIGS. 3 to 7, a method of manufacturing the liquid crystal display device according to the first embodiment of the present invention will be described.
[0016]
As shown in FIGS. 3 and 4, a sealant 4, which is an ultraviolet-curable resin, is arranged in a frame shape on the upper surface of the color filter substrate 2, and a liquid crystal is dropped inside the frame shape made of the sealant 4 as a dropping step. I do. The liquid crystal can be dropped using a device such as a dispenser. Since the dropped liquid crystal has a surface tension, it remains as a liquid crystal droplet 1 on the upper surface of the color filter substrate 2 and remains in a certain area. The dropping of the liquid crystal is repeated while changing the position on the upper surface of the color filter substrate 2, and as a result, as shown in FIGS. 3 and 4, the liquid crystal drops 1 are arranged at many points.
[0017]
Next, as a bonding step, as shown in FIG. 5, a TFT substrate 3 on which no liquid crystal is dripped is coated with a polyimide alignment film 34 (see FIG. 2) from above the color filter substrate 2 in a vacuum atmosphere, as shown in FIG. The two substrates are overlapped as shown in FIG. Further, when the distance between the color filter substrate 2 and the TFT substrate 3 is reduced and the sealant 4 comes into contact with both the color filter substrate 2 and the TFT substrate 3, the atmosphere is returned to the atmospheric pressure. Then, due to the atmospheric pressure, the sealant 4 sandwiched between the color filter substrate 2 and the TFT substrate 3 is crushed to some extent, and the liquid crystal is filled inside the uncured sealant 4.
[0018]
Next, this structure is placed on the stage 5 as shown in FIG. Alternatively, the bonding step may be performed on stage 5 from the beginning. Light for curing the sealant 4 is irradiated from the upper side in the drawing, that is, from the TFT substrate 3 side. In this case, since the sealant 4 is an ultraviolet curable resin, the ultraviolet rays 11 are irradiated. The ultraviolet irradiation may be performed after a mask for concealing a portion not to be irradiated with ultraviolet light is arranged above the TFT substrate 3. The irradiation of the ultraviolet rays 11 cures the sealant 4. Alternatively, if the curing is not sufficient or if it is desired to ensure the curing, a heat treatment is performed after irradiation with ultraviolet rays using a sealant that also has thermosetting properties to cure the uncured portion of the sealant. In particular, in the present embodiment, the ultraviolet rays 11 are radiated from the side of the TFT substrate 3, so that the illuminating light is blocked in the shaded portions such as the wiring included in the TFT substrate 3, and the sealant 4 is sufficiently cured. May not be done. Therefore, it is preferable to perform heat treatment after irradiation.
[0019]
By curing the sealant 4, a structure in which the liquid crystal 10 is sealed between two substrates (also referred to as a “liquid crystal panel”) is completed. A liquid crystal display device can be obtained by connecting a drive circuit or the like to this structure as needed.
[0020]
(Action / Effect)
In the liquid crystal display device obtained by the manufacturing method according to the present embodiment, no drop mark was generated even in the lighting inspection after completion.
[0021]
On the other hand, for comparison, a color filter substrate and a TFT substrate having the same structure are used, and liquid crystal is dropped only on the TFT substrate side instead of the color filter substrate. When the ultraviolet ray was irradiated from the side of the TFT substrate with the mark on the upper side, a drop mark was observed in the lighting inspection after completion.
[0022]
(Embodiment 2)
(Production method)
With reference to FIGS. 3 to 6 and FIG. 8, a method of manufacturing the liquid crystal display device according to the second embodiment of the present invention will be described.
[0023]
Each process up to the laminating process shown in FIGS. 3 to 6 is the same as that described in the first embodiment.
[0024]
Next, the structure is turned upside down, and the color filter substrate 2 is placed on the upper side and the TFT substrate 3 is placed on the lower side, so that the structure is placed on the stage 5 as shown in FIG. Light for curing the sealant 4 is irradiated from the upper side in the figure, that is, from the color filter substrate 2 side. In this case, since the sealant 4 is an ultraviolet curable resin, the ultraviolet rays 11 are irradiated. The ultraviolet irradiation may be performed after a mask for concealing a portion not to be irradiated with the ultraviolet light is arranged above the color filter substrate 2. The irradiation of the ultraviolet rays 11 cures the sealant 4. Alternatively, if the curing is not sufficient or if it is desired to ensure the curing, if the sealing agent also has a thermosetting property, heat treatment after ultraviolet irradiation to cure the uncured portion of the sealing agent. It may be.
[0025]
The subsequent steps are the same as those described in the first embodiment.
(Action / Effect)
In the manufacturing method of the liquid crystal display device according to the present embodiment, after the laminating step, the structure is turned upside down and irradiation is performed from the color filter substrate 2 side before irradiation with light for curing the sealant. Unlike the case where irradiation is performed from the side of the TFT substrate 3, the sealing agent 4 can be efficiently cured without the irradiation light being shielded by wiring or the like in the TFT substrate 3.
[0026]
In the liquid crystal display device obtained by the manufacturing method according to the present embodiment, no drop mark was generated even in the lighting inspection after completion.
[0027]
On the other hand, for comparison, using a color filter substrate and a TFT substrate having the same structure, liquid crystal is dropped only on the TFT substrate side, not on the color filter substrate, and the liquid crystal is bonded in the same manner, and the upper side, that is, the color filter substrate side When UV irradiation was performed from the above, a drop mark was observed in the lighting inspection after completion.
[0028]
(Embodiment 3)
(Production method)
Referring to FIGS. 3, 4, 9, and 10, a method for manufacturing the liquid crystal display device according to the third embodiment of the present invention will be described.
[0029]
The dropping step is the same as that described in the first embodiment. That is, as shown in FIGS. 3 and 4, liquid crystal is dropped on the upper surface of the color filter substrate 2 to obtain a liquid crystal in which the liquid crystal drops 1 are arranged at many points.
[0030]
Next, the color filter substrate 2 is turned upside down so that the surface on which the liquid crystal is dropped faces downward. The liquid crystal droplet 1 can remain on the surface of the color filter substrate 2 due to the surface tension both when the color filter substrate 2 is inverted and in the bonding step described later. Then, as a laminating step, the color filter substrate 2 is brought close to the TFT substrate 3 on which no liquid crystal is dropped as shown in FIG. Overlap. Further, when the distance between the color filter substrate 2 and the TFT substrate 3 is reduced and the sealant 4 comes into contact with both the color filter substrate 2 and the TFT substrate 3, the atmosphere is returned to the atmospheric pressure. Then, similarly to the laminating process of the first embodiment, the sealing agent 4 sandwiched between the color filter substrate 2 and the TFT substrate 3 is crushed to some extent by the atmospheric pressure, and the uncured sealing agent 4 The liquid crystal is filled.
[0031]
Next, this structure is placed on the stage 5 with the color filter substrate 2 on the upper side, that is, the posture as it is. Alternatively, the bonding step may be performed on stage 5 from the beginning. By doing so, it is not necessary to replace the structure obtained after the laminating step on the stage 5, which is convenient. In a state where the structure is placed on the stage 5, as shown in FIG. 8, ultraviolet rays 11 are irradiated from the side of the color filter substrate 2, that is, the upper side in FIG. . The details of the irradiation step and the steps thereafter are the same as those described in the second embodiment.
[0032]
(Action / Effect)
In the liquid crystal display device obtained by the manufacturing method according to the present embodiment, no drop mark was generated even in the lighting inspection after completion.
[0033]
In each of the above embodiments, the sealant 4 is disposed on the same substrate surface on which the liquid crystal is dropped. However, the substrate on which the sealant 4 is disposed need not be the same as the substrate on which the liquid crystal is dropped. Absent. The same effect can be obtained by arranging the sealant 4 on the surface of the TFT substrate 3 while dropping the liquid crystal on the color filter substrate 2.
[0034]
In each of the above embodiments, the example of the ultraviolet curable resin is given as the material of the sealant 4 and the example of ultraviolet light is given as the light for curing the sealant 4, but in applying the present invention, Not limited to combinations. A material that cures with light other than ultraviolet light may be used as a sealant, and irradiation with appropriate light for curing the sealant may be performed. Even in that case, the effects of the present invention can be obtained.
[0035]
In FIG. 4, the liquid crystal droplets 1 are arranged in a number of points arranged in a matrix, but the arrangement of the liquid crystal on the color filter substrate is not limited to such a pattern. Other patterns may be arranged as long as an appropriate amount of liquid crystal is arranged on the color filter substrate.
[0036]
In each of the above embodiments, the mating substrate to be bonded to the color filter substrate is a TFT substrate, but a driving element substrate provided with some driving element other than the TFT element instead of the TFT element may be used.
[0037]
In each of the above embodiments, the substrate on which the sealant is disposed is a color filter substrate, but the sealant may be disposed on the drive substrate side instead of the color filter substrate. In this case, the timing of performing the step of disposing the sealant may be before or after the dropping step, or may be performed simultaneously with the dropping step.
[0038]
The above embodiments have been described on the assumption that one liquid crystal sealing portion is formed by bonding one set of substrates 2 and 3 and one liquid crystal panel is manufactured as a result. The present invention can be applied to a case where a plurality of liquid crystal sealing portions are formed by bonding the substrates 2 and 3 to produce a plurality of liquid crystal panels as a result, that is, a so-called “multi-pane” case.
[0039]
Further, in the ultraviolet irradiation step, the ultraviolet may be irradiated from below with the color filter substrate 2 facing downward and the TFT substrate 3 facing upward. In this case, the stage 5 needs to be made of a light-transmitting material such as quartz so that ultraviolet rays can be transmitted. However, if the stage 5 is made of quartz or the like, the cost for the stage 5 increases. Further, when a light-transmitting stage such as quartz is used, a normal suction stage may not be used for fixing the substrate. In addition, when a light-transmitting stage such as quartz is used, the area to be masked when irradiating ultraviolet rays is different due to a difference in the number of pieces to be taken in the case of multi-face mounting or a difference in the size of the liquid crystal sealing portion. , Mask replacement is required. For these reasons, the ultraviolet irradiation device may be complicated for fixing the substrate or exchanging the mask, and the productivity may be deteriorated. Therefore, as described in Embodiment Modes 2 and 3, it is preferable to irradiate ultraviolet rays from above with the color filter substrate 2 facing upward.
[0040]
Note that the above-described embodiment disclosed this time is illustrative in all aspects and is not restrictive. The scope of the present invention is defined by the terms of the claims, rather than the description above, and includes all modifications within the scope and meaning equivalent to the terms of the claims.
[0041]
【The invention's effect】
ADVANTAGE OF THE INVENTION According to this invention, generation | occurrence | production of a drip mark can be prevented.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view of a color filter substrate.
FIG. 2 is a sectional view of a TFT substrate.
FIG. 3 is a cross-sectional view of the color filter substrate after performing a dropping step of the method for manufacturing a liquid crystal display according to Embodiments 1 to 3 according to the present invention.
FIG. 4 is a plan view of the color filter substrate after performing a dropping step of the method for manufacturing a liquid crystal display according to Embodiments 1 to 3 according to the present invention.
FIG. 5 is a first explanatory diagram of a bonding step of the method for manufacturing a liquid crystal display device in Embodiment 1 based on the present invention.
FIG. 6 is a second explanatory view of the bonding step of the method for manufacturing the liquid crystal display device according to the first embodiment based on the present invention.
FIG. 7 is an explanatory diagram of an irradiation step of the method for manufacturing the liquid crystal display device according to the first embodiment based on the present invention.
FIG. 8 is an explanatory view of an irradiation step of the method for manufacturing a liquid crystal display device according to the second embodiment of the present invention.
FIG. 9 is a first explanatory view of a bonding step of the method for manufacturing a liquid crystal display device in Embodiment 3 based on the present invention.
FIG. 10 is a second explanatory diagram of the bonding step of the method for manufacturing the liquid crystal display device in the third embodiment according to the present invention.
[Explanation of symbols]
Reference Signs List 1 liquid crystal droplet, 2 color filter substrate, 3 TFT substrate, 4 sealant, 5 stage, 10 liquid crystal, 11 ultraviolet rays, 20 glass substrate, 21 color filter layer, 22 counter electrode, 23 polyimide alignment film, 30 glass substrate, 31 ITO Transparent pixel electrode, 32 TFT element, 33 insulating layer, 34 polyimide alignment film.

Claims (4)

A method for manufacturing a liquid crystal display device by enclosing liquid crystal between a driving element substrate and a color filter substrate,
A dropping step of dropping liquid crystal on one surface of the color filter substrate,
A method of manufacturing the liquid crystal display device, comprising: laminating the color filter substrate and the driving element substrate not dripping liquid crystal after the dropping step. A sealing agent disposing step of forming a frame shape of a photocurable resin as a sealing agent on one of the driving element substrate and the color filter substrate before the laminating step,
Irradiating light for curing the photocurable resin from the side of the color filter substrate after the laminating step,
A method for manufacturing a liquid crystal display device according to claim 1. The method of manufacturing a liquid crystal display device according to claim 1, wherein the bonding step is performed by stacking the driving element substrate from above the color filter substrate. 2. The manufacturing of the liquid crystal display device according to claim 1, wherein the laminating step is performed by stacking the color filter substrate on which the surface on which the liquid crystal is dropped is directed downward to the upper side of the driving element substrate. Method.

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