JP2002229030A - Method for manufacturing liquid crystal display, and liquid crystal display - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for manufacturing a liquid crystal display solving problems, such as generation of static electricity caused by liquid crystal alignment treatment with rubbing treatment, easily improving productivity and further broadening the range of choice for a substrate for the device and the liquid crystal display device. SOLUTION: A first mother substrate 10 having a polymer material layer subjected to alignment treatment is prepared; a second mother substrate 15 is press-fixed to the first mother substrate 10 and the aligned state on the first mother substrate 10 is transferred onto the second mother substrate 15; and furthermore, the second mother substrate 15 is press-fixed to the substrates 17, 21 for devices and the aligned state on the second mother substrate 15 is transferred onto the substrates for the device 17, 21.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of manufacturing a liquid crystal display device for displaying an image by using a liquid crystal, and more particularly to a method of manufacturing a liquid crystal display device having an alignment process for an alignment film.

[0002]

2. Description of the Related Art A liquid crystal display device changes a specific molecular arrangement of a liquid crystal to another different molecular arrangement by an external action such as an electric field, and displays a change in optical characteristics during the change as a visual change. It is configured to change. In order to arrange the liquid crystal molecules in a specific alignment state, it is usual to perform an alignment treatment on the surface of the glass substrate sandwiching the liquid crystal.

In a conventional twisted nematic (TN) type liquid crystal element or the like, a so-called rubbing method is used in which an alignment film such as polyimide is formed on the entire glass substrate sandwiching liquid crystal, and the alignment film is rubbed in one direction with a rubbing cloth. The law has been adopted. As a typical example of the rubbing method, the rubbing roller is moved while a rubbing roller wound with a rubbing cloth such as a cotton cloth is brought into contact with an alignment film such as polyimide on a substrate. Then, an alignment process is performed on the entire alignment film formed on the device substrate.

In an active matrix type liquid crystal display device, driving elements such as thin film transistors (TFTs) and wiring are formed on the surface of a device substrate. When performing a rubbing process on such an active matrix type liquid crystal display device, if the rubbing process is performed at a stage where the driving elements and the wirings are formed on the surface of the device substrate, the driving elements and the wirings are also rubbed. As a result, As a result, rubbing or the like may cause electrostatic breakdown. Further, there is also a problem that dust is attracted around the driving element by the rubbing process.

As a technique for solving such a problem at the time of the rubbing treatment, a sub-substrate used for an actual liquid crystal cell and a mother substrate subjected to an alignment treatment are arranged to face each other, and a primary liquid crystal material is injected between the two substrates. A technique is known in which the state of alignment of a primary liquid crystal material is preserved during alignment, and the state of alignment is successively transferred to a sub-substrate.
No. 3,794, there is a description thereof. Also, JP-A-6-3
No. 672 discloses a technique for omitting a rubbing treatment, in which an alignment material sheet made of a high molecular organic material such as polyimide is mounted on a rotating roller and transferred from the rotating roller onto a glass substrate to impart an alignment effect. Methods are known. Further, as a technique for providing a liquid crystal orientation by bringing a uniaxial member into close contact, a technique described in JP-A-6-43458 is known.

[0006]

The above-mentioned Patent No. 277379 in which a primary liquid crystal material is injected between a pair of substrates, and the alignment state is transferred to a daughter substrate by a memory function of the primary liquid crystal material.
In the technique described in Japanese Patent Application Laid-Open No. 4 (1999) -1995, it is necessary to enclose a primary liquid crystal material every time a sub-substrate is produced, which complicates the manufacturing process and makes it difficult to increase the productivity of the liquid crystal display device.

Further, in the technique disclosed in Japanese Patent Application Laid-Open No. Hei 6-3672, in which an orientation material sheet made of a high molecular organic substance is transferred from a rotating roller onto a glass substrate to impart an orientation effect, the glass substrate is heated to about 200 ° C. It is necessary to raise the temperature to a high temperature. For example, when a synthetic resin substrate is used to make the liquid crystal display device flexible, a problem occurs in the heat resistance of the substrate itself. Also, Japanese Patent Laid-Open No. 6-4
In the technique described in Japanese Patent No. 3458, in which a uniaxial member is brought into close contact to impart liquid crystal orientation, since rubbing is not performed, it is possible to solve the problem of dust.
After the application of the polymer film, a heat treatment such as annealing is required, which causes the same problem of heat resistance, and narrows the range of choice of the device substrate.

Therefore, the present invention can solve the problem of static electricity and the like generated by the liquid crystal alignment treatment by the rubbing treatment, can easily improve the productivity in the process, and can widen the choice of the device substrate. It is an object of the present invention to provide a liquid crystal display device manufacturing method and a liquid crystal display device.

[0009]

In order to solve the above-mentioned problems, a method of manufacturing a liquid crystal display device according to the present invention comprises the steps of: bonding a second mother substrate to a first mother substrate having a polymer material layer subjected to an alignment treatment; Then, the orientation state on the first motherboard is transferred onto the second motherboard, and the second motherboard is pressed against the device substrate to transfer the orientation state on the second motherboard onto the device substrate. It is characterized by doing. Various methods can be used as a method for press-bonding the substrates, for example, surface contact between the substrates can be used, and the alignment state itself is, for example, a polymer material such as an electromagnetic wave-curable resin. It is also possible to use a membrane.

According to the method of manufacturing a liquid crystal display device of the present invention, the alignment state is transferred from the first mother substrate to the second mother substrate,
The alignment state is transferred from the second mother substrate to the device substrate. The transfer of the alignment state between the substrates is performed by combining the substrates, and the transfer of the liquid crystal alignment state is not performed by direct rubbing. For example, when an electromagnetic wave-curable resin such as an ultraviolet-curable resin is used for transferring the alignment state, there is no need to heat the device substrate, and therefore, it is possible to use a required polymer substrate as the device substrate. Become.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the method for manufacturing a liquid crystal display device according to the present invention will be described below with reference to the drawings. FIGS. 1 to 3 are views showing an embodiment of a method of manufacturing a liquid crystal display device in the order of steps, and show each step which proceeds in alphabetical order.

First, as shown in FIG. 1A, a polymer film 11 is formed on a first mother substrate 10. The first mother substrate 10 can hold the polymer film 11 in particular, and if it is a material that can be rubbed by the next roller,
It can be constituted by a known material. As the first mother substrate 10, for example, a glass substrate, an aluminum substrate, stainless steel, iron, another metal substrate, or a synthetic resin substrate can be used. On the first mother substrate 10, for example, a polymer film 11 made of a polyimide film is formed on substantially the entire surface by a spin coating method, a printing method using a roll coater, or the like. As the polymer film 11, a polyamide film, a polyimide amide film, a polypeptide alcohol film, or the like may be formed in addition to the polyimide film.

Next, as shown in FIG. 1B, the polymer film 11 on the first mother substrate 10 is brought into contact with the rubbing roller 13 in order to take the mold in the alignment state. The rubbing roller 13 has a structure in which a rubbing cloth 14 such as a cotton cloth such as nylon is adhered to the roller surface. The first mother substrate 10 is moved to the right in the figure while the peripheral surface of the rubbing roller 13 is kept in contact with the surface of the polymer film 11 on the first mother substrate 10. At this time, the rubbing cloth 14 provided on the peripheral surface of the rubbing roller 13 rubs the surface of the polymer film 11 on the first mother substrate 10, and the surface 11b having no alignment state becomes the surface 11a having the alignment state. Processed. In the present embodiment, the polymer film 11 on the first mother substrate 10 is subjected to the orientation treatment by the rubbing treatment using the rubbing roller 13. The orientation state of the polymer film 11 on the substrate 10 may be formed.

Next, the first alignment treatment is performed.
The polymer film 11 on the motherboard 10 is opposed to the second motherboard 15 as shown in FIG. The second motherboard 15 can also be made of a known material similarly to the first motherboard 10 described above.
For example, glass substrate, aluminum substrate, stainless steel,
An iron, other metal substrate, a synthetic resin substrate, or the like can be used. On this second mother substrate 15, an ultraviolet curable resin layer 16 is formed. The UV-curable resin layer 16 is a resin layer formed by spin coating or another printing method, and is a wet uncured state before the second mother substrate 15 and the first mother substrate 10 are pressed. State or half-cured state. The ultraviolet curable resin layer 16 may be a single layer, but may be formed in advance, such as a primer film, in order to enhance the adhesion to the second mother substrate 15, or may be a composite layer with another layer. The ultraviolet curable resin layer 16 is formed on substantially the entire surface of the second mother substrate 15. Since the ultraviolet curable resin layer 16 is cured by receiving ultraviolet rays, at least one of the second mother substrate 15 and the first mother substrate 10 is preferably a transparent material such as a glass substrate. Note that, on the second mother substrate 15, an electron beam curable resin, another electromagnetic wave curable resin, or a layer that can function as another mold can be formed instead of the ultraviolet curable resin layer 16. Further, as the structure of the first mother substrate to be crimped to the second mother substrate 15, an aluminum substrate having a structure made of tungsten wire cloth may be used. When using a type,
It is also possible to apply a release agent or the like to the surface of the mold.

When the second mother board 15 and the first mother board 10 face each other, as shown in FIG. 2D, they are pressed by a required press device. Then, since the surface of the ultraviolet-curable resin layer 16 is in an uncured state, the surface of the ultraviolet-curable resin layer 16 follows the shape of the polymer film 11 on the first mother substrate 10 on which the alignment treatment has been performed. Is deformed. The ultraviolet curable resin layer 16 is substantially uniformly formed on the first mother substrate 10.
When the transparent substrate side is the first mother substrate 10 when it is pressure-bonded to the upper polymer film 11, it passes through the first mother substrate 10, or when the transparent substrate side is the second mother substrate 15, the second mother substrate 15 and is irradiated with ultraviolet rays. The irradiation of the ultraviolet rays may be performed all at once, or may be performed by sequentially curing the lines or spots by scanning them. The surface of the ultraviolet-curable resin layer 16 is deformed along with the shape of the polymer film 11 on the first mother substrate 10 by the irradiation of the ultraviolet light, and as a result, the alignment state on the polymer film 11 is changed to the ultraviolet-curable resin layer. 16 is transferred to the surface.

UV curable resin layer 1 on second mother substrate 15
After transferring the orientation state to the surface 16a of FIG. 6, (e) of FIG.
2, the second mother substrate 15 is opposed to the device substrate 17. Here, the device substrate 17 is a pair of substrates of a liquid crystal display device, and for example, a glass substrate or the like can be used, but polyethylene naphthalate, esters such as polyethylene terephthalate, polyamide, polycarbonate, cellulose esters such as cellulose acetate, and the like. Fluoropolymers such as polyvinylidene fluoride, polytetrafluoroethylene-cohexafluoropropylene, polyethers such as polyoxymethylene, polyacetals, polyolefins such as polystyrene, polyethylene, polypropylene and methylpentene polymers, and polyimideamides and polyetherimides Polyimide, PMMA
Acrylic can be mentioned as an example. When such a synthetic resin is used as a support, it can be formed into a rigid substrate shape that does not easily bend, but it can also be formed into a flexible film-like structure.

An alignment film 18 is formed on the device substrate 17, and the alignment film 18 is made of the same UV-curable resin as the UV-curable resin layer 16. The alignment film 18 is a resin layer formed by spin coating or another printing method, and is in an uncured wet state or a half-cured state before being pressed against the second mother substrate 15. . The alignment film 18 may be a single layer, but may be formed in advance, such as a primer film, in order to enhance the adhesion to the device substrate 17, or may be a composite layer with another layer. The alignment film 18 is formed on substantially the entire surface of the device substrate 17, and is cured by receiving ultraviolet rays. Note that the alignment film 18 on the device substrate 17 may be formed with an electron beam curable resin, another electromagnetic wave curable resin, or a layer that can function as another mold. Although not shown, a pixel electrode, a wiring layer, and the like can be formed between the alignment film 18 and the device substrate 17, and the device substrate 17 is on the counter substrate side facing the array substrate. A common electrode can be provided between the alignment film 18 and the device substrate 17.

After the second mother substrate 15 is opposed to the device substrate 17, the second mother substrate 15 and the device substrate 17 are pressed. Then, the alignment state transferred to the surface 16 a of the ultraviolet curing resin layer 16 of the second mother substrate 15 is transferred to the surface of the alignment film 18 on the device substrate 17. This process can be completed in an extremely short time since the process is performed by irradiation with ultraviolet rays, and the substrate can be prevented from being heated to a high temperature.
FIG. 2F shows the surface 18 of the alignment film 18 on the device substrate 17.
FIG. 6 is a diagram illustrating a state where an alignment state is transferred to a in a desired manner.

The above is the description of the device substrate on the array substrate side on which the pixel control element such as a thin film transistor element is formed. The alignment state can be transferred using the mother substrate.

FIG. 3 (g) is a view showing that the alignment films 23 and 18 on which the alignment states are transferred are opposed to each other. The configuration of the active matrix type liquid crystal display device manufactured according to the present embodiment is also shown in FIG. Show. The configuration on the opposite side has a structure in which a common electrode 22 is formed on an opposite side device substrate 21 and an alignment film 23 is formed thereon. On the other hand, an alignment film 18 is formed on a device substrate 17 on the array substrate side, and a thin film transistor element 19 serving as a pixel control element is also transferred. The thin film transistor element 19 is obtained by transferring a transistor element formed on another element forming substrate to a predetermined position together with the element. The thin film transistor element 19 is connected to a pixel electrode (not shown) below the alignment film 18 after the transfer. You. Note that the illustrated thin film transistor element 1
The structure 9 is an example, and the wiring and the like connected to the source / drain may be formed after the transfer.

When the opposing device substrate 21 and the device substrate 17 face each other, the liquid crystal material 25 is sealed.
The injection between the substrates can be performed by a method such as vacuum injection or capillary injection. As described above, the alignment film 23,
Since the alignment state is transferred to each surface of the substrate 18 via the first motherboard and the second motherboard, a reliable liquid crystal display is realized. In particular, from the second mother board to the device boards 17, 2
In the transfer of the alignment state to the alignment films 18 and 23, instant processing using an ultraviolet curable resin is possible. For example, even when these device substrates 17 and 21 are made of a synthetic resin material, Since the influence of heat is small, the device substrates 17 and 2
1 can be used as a part of the liquid crystal display device as it is. In other words, by using this embodiment, the range of selection of a substrate that can be used as a liquid crystal display device is expanded. Further, since the final transfer of the alignment state is not a rubbing process, problems such as static electricity do not occur, and furthermore, since the transfer is instantaneously performed by pressing the surfaces together, the productivity is improved and the throughput can be increased.

FIGS. 4A and 4B are views for explaining another embodiment of the present invention. FIG. 4A shows an example of a liquid crystal display device in which the alignment state is changed in the horizontal direction, and FIG. 4B shows a rectangular pattern. This is an example of a liquid crystal display device having different alignment states.

The liquid crystal display device 40 shown in FIG. 4A has a region 41 having a first alignment direction, a region 42 having a second alignment direction, a region 43 having a third alignment direction, and a second alignment direction. Region 42, Region 4 having first alignment direction
1 are arranged in order in the horizontal direction, and different alignment treatments are made on the polymer material film on the second mother substrate, and are collectively transferred.

The liquid crystal display device 4 shown in FIG.
5, a region 46 having a first alignment direction, a region 47 having a second alignment direction, a region 48 having a third alignment direction, a region 49 having a fourth alignment direction, and a region 50 having a fifth alignment direction are displayed on the screen. Are arranged in order from the outer side to the inner side, and different alignment treatments are made on the polymer material film on the second mother substrate, and are collectively transferred.

Even when such a liquid crystal display device having a partially different alignment state is formed, if a plurality of regions having different alignment directions are formed on the second mother substrate functioning as a mold,
Eventually, it can be transferred collectively. Therefore, a high-quality liquid crystal display device can be manufactured while increasing the throughput.

In the above embodiment, an active matrix type liquid crystal display device has been mainly described, but the present embodiment is also applicable to a simple matrix type liquid crystal display device and a method of manufacturing the same. Further, the pixel control element is not limited to the thin film transistor element, and may be an element such as an MIM element or a thin film diode. The formation of the element is not limited to transfer, and the pixel control element is formed on an element forming substrate.
It is also possible to apply the method for manufacturing a liquid crystal display device of the present embodiment to an alignment film formed thereon.

[0027]

As described above, according to the liquid crystal display device and the method of manufacturing the liquid crystal display device of the present invention, when the alignment state is transferred from the second mother substrate to the alignment film of the device substrate, ultraviolet curing is performed. Instant processing using mold resin is possible.For example, even if these device substrates are made of a synthetic resin material, the device substrate can be used as it is as a part of the liquid crystal display device because the influence of heat is small. The range of selection of a substrate that can be used as a display device is widened. In addition, since the final transfer of the alignment state is not a rubbing process, there is no problem such as static electricity, and since the transfer of the alignment state is performed from instantaneous pressure bonding of the surfaces, the productivity is improved, Throughput can be increased.

[Brief description of the drawings]

FIGS. 1A and 1B are process cross-sectional views illustrating an embodiment of a method for manufacturing a liquid crystal display device according to the present invention, in which FIG. 1A is a process cross-sectional view illustrating a process of forming a polymer film, and FIG. (C) is a process sectional view in which the first mother substrate is opposed to the second mother substrate.

FIG. 2 is a process cross-sectional view showing one embodiment of a method for manufacturing a liquid crystal display device of the present invention, in which (d) is a process cross-sectional view showing a process of transferring an alignment state by irradiation with ultraviolet light, and (e) is a second process cross-sectional view. Cross-sectional view of the process where the mother board is opposed to the device board,
(F) is a process sectional view in which the alignment state is transferred to the alignment film on the second mother substrate.

FIG. 3 is a process cross-sectional view showing one embodiment of a method for manufacturing a liquid crystal display device of the present invention, in which (g) is a process cross-sectional view in which the opposing device substrate is opposed to the device substrate; It is a process sectional view in which a liquid crystal material was sealed.

FIG. 4 is a view for explaining a liquid crystal display device according to another embodiment of the present invention, wherein FIG. 4 (a) is a schematic view showing each alignment region of the liquid crystal display device having different alignment states in the horizontal direction. FIG. 4B is a schematic diagram showing each alignment region of the liquid crystal display device in which the alignment state is changed in a rectangular pattern.

[Explanation of symbols]

 Reference Signs List 10 first mother substrate 11 polymer film 13 rubbing roller 15 second mother substrate 16 ultraviolet curable resin 17 device substrate 18 alignment film 21 facing device substrate 22 common electrode 23 alignment film 25 liquid crystal material

Claims (12)

[Claims] A first mother substrate having a polymer material layer subjected to an alignment treatment, a second mother substrate being pressed, and an alignment state on the first mother substrate is transferred onto the second mother substrate; A method for manufacturing a liquid crystal display device, wherein a second mother substrate is pressed against a device substrate to transfer an alignment state on the second mother substrate to the device substrate. 2. A curable resin is applied on the device substrate, and when the second mother substrate is pressed on the device substrate,
2. The method according to claim 1, wherein the alignment state on the second mother substrate is transferred onto the device substrate by curing the curable resin. 3. The method according to claim 2, wherein the curable resin is an electromagnetic wave curable resin. 4. A curable resin is applied on the second substrate, and when the first mother substrate is pressed against the second substrate,
2. The method according to claim 1, wherein the alignment state on the first mother substrate is transferred onto the second substrate by curing the curable resin. 5. The method according to claim 2, wherein the curable resin is an electromagnetic wave curable resin. 6. The pressure bonding between the second mother substrate and the first mother substrate and the pressure bonding between the device substrate and the second mother substrate are pressure bonding between surfaces of the respective substrates. The method for manufacturing a liquid crystal display device according to claim 1. 7. The method according to claim 1, wherein the polymer material layer of the first mother substrate has been subjected to the alignment treatment by a rubbing treatment. 8. The method according to claim 1, wherein the device substrate is formed of a synthetic resin material. 9. The method according to claim 1, wherein a pixel control element is transferred onto the device substrate after transferring the alignment state onto the device substrate. 10. A second motherboard is pressed against a first motherboard having a polymer material layer that has been subjected to an alignment treatment so as to include a partially different alignment direction, and the second motherboard is partially compressed on the first motherboard. The alignment state including the alignment direction is transferred onto the second mother substrate, and the second mother substrate is pressed against the device substrate to change the alignment state including the partially different alignment direction on the second mother substrate to the device substrate. A method for manufacturing a liquid crystal display device, wherein the liquid crystal display device is transferred onto the liquid crystal display device. 11. A second mother substrate is pressed against a first mother substrate having a polymer material layer subjected to an alignment treatment, and an alignment state on the first mother substrate is transferred onto the second mother substrate. A liquid crystal display device having a structure in which a second mother substrate is pressed against a device substrate and an alignment state on the second mother substrate is transferred onto the device substrate. 12. The liquid crystal display device according to claim 11, wherein an alignment process is performed so as to include a partially different alignment direction.