JPH11167091A - Manufacture of liquid crystal display device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To manufacture a hard transparent substrate and a flexible transparent substrate in combination by a device for the hard transparent substrate without using a device for rolling the flexible transparent substrate and investing much facility cost. SOLUTION: A flexible sheet 42 is formed which has a size corresponding flexible transparent substrates 18 each having an ITO layer 30 for a transparent electrode 24 formed on one surface. A peelable adhesive material 34 is used to stick the flexible sheet 42 on a base plate 52 of nearly the same size with the ITO layer 30 up. Transparent electrodes 24 are formed by working the ITO layer 30 of the flexible sheet 42 on the base plate 52. The flexible sheet 42 is peeled off the adhesive material 34. On one surface of a hared sheet 40 of size corresponding to hard transparent substrates 16, transparent electrodes 22 are formed corresponding to the respective hard transparent substrates 16. The hard sheet 40 and flexible sheet 42 are adhered and assembled having the transparent electrodes 22 and 24 opposite each other.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a method for manufacturing a liquid crystal display device, and more particularly, to a method for manufacturing a liquid crystal display device having a hard transparent substrate and a flexible transparent substrate.

[0002]

2. Description of the Related Art In recent years, liquid crystal display devices have been widely used as means for displaying visible information in electronic devices such as computers, electronic organizers, pagers and mobile phones.

This liquid crystal display device is generally formed by enclosing liquid crystal in a gap formed between a pair of transparent substrates, a so-called cell gap.

[0004] The pair of transparent substrates may be formed of a hard material such as glass which does not bend, or may be formed of a flexible material such as a plastic film.

In a liquid crystal display device with an input function, a hard transparent substrate such as glass which is not bent is disposed at the center, and a transparent substrate made of a flexible material is disposed above and below the transparent substrate. There is also known a display device which is formed to be thin and lightweight, and to reduce the displacement due to parallax by forming the display device.

Meanwhile, a transparent substrate made of a hard material such as glass which does not bend usually flows, for example, while a mother glass plate is mounted on a magazine in single sheets and flows, whereas a transparent substrate made of a flexible material is used. The transparent substrate makes continuous use of, for example, a roll film by utilizing its features.

Therefore, when an attempt is made to form a liquid crystal display device by combining a transparent substrate made of a hard material and a transparent substrate made of a flexible material, in addition to an apparatus for manufacturing a transparent substrate made of a hard material, a flexible substrate is required. Therefore, a manufacturing apparatus for roll processing of a transparent substrate made of a conductive material is required, and the equipment cost is increased.

[0008] The present invention has been made in view of such a point, and in the case of manufacturing by combining a hard transparent substrate and a flexible transparent substrate, a manufacturing apparatus for roll processing of a flexible transparent substrate. It is an object of the present invention to provide a method of manufacturing a liquid crystal display device which can be manufactured without using a transparent substrate and can be manufactured by a manufacturing apparatus for a hard transparent substrate without a large capital investment.

[0009]

According to one aspect of the present invention, there is provided a liquid crystal display device having a hard transparent substrate having a transparent electrode on an inner surface thereof and a flexible transparent substrate. Forming a flexible sheet having a size corresponding to a plurality of the flexible transparent substrates by cutting a flexible material having a conductive layer for the transparent electrode formed on one surface thereof. Using a peelable adhesive material, attaching the flexible sheet to a base plate having substantially the same size with the conductive layer facing, and the flexible sheet attached to the base plate. Processing the conductive layer to form a plurality of predetermined patterns of transparent electrodes corresponding to the respective flexible transparent substrates, and peeling the flexible sheet on which the transparent electrodes are formed from the adhesive. And a rigid sheet having a size corresponding to the plurality of rigid transparent substrates. Forming a plurality of transparent electrodes in a predetermined pattern wherein corresponding to each rigid transparent substrate to the surface,
Bonding the hard sheet and the flexible sheet each having the transparent electrode formed thereon, with the transparent electrodes facing each other, and assembling the rigid sheet and the flexible sheet.

According to the present invention, the flexible sheet is flowed in a state where the flexible sheet is adhered to the base plate with the adhesive material to form the electrodes. The positioning can be reliably performed by the base plate, and the electrodes can be formed using the manufacturing apparatus for the hard transparent substrate.
It is not necessary to use a manufacturing apparatus for roll processing, so that capital investment is not required and equipment cost can be reduced.

Then, after forming the electrodes, the flexible sheet is peeled off and assembled with the hard sheet, thereby making it possible to carry out the same production as before.

According to a second aspect of the present invention, in the first aspect, the adhesive has a small adhesive strength between the flexible substrate-side adhesive surface and the base plate-side adhesive surface.

According to the present invention, in addition to the first aspect,
By making the adhesive strength of the adhesive material smaller on the flexible substrate side than on the base plate side, when peeling the flexible sheet, the adhesive material peels off from the base plate together with the flexible sheet. In addition, it is possible to prevent the adhesive from being difficult to peel off from the flexible sheet, and to reliably peel off only the flexible sheet while the adhesive is adhered to the base plate.

According to a third aspect of the present invention, in the first aspect, the adhesive is formed of a material whose adhesive strength decreases at least on the flexible substrate-side adhesive surface when irradiated with ultraviolet rays. .

According to the present invention, in addition to the first aspect,
By performing the ultraviolet irradiation, the adhesive strength of the adhesive surface on the flexible substrate side is reduced, so that the flexible sheet can be reliably separated from the adhesive. In this case, the UV irradiation
For example, by using a UV cleaning process after forming the electrodes, the process can be performed without increasing the number of processes.

According to a fourth aspect of the present invention, in any one of the first to third aspects, the pressure-sensitive adhesive has a flexibility capable of following shrinkage of the flexible sheet.

According to the present invention, in addition to any one of the first to third aspects, the adhesive follows the heat shrinkage of the flexible sheet. Stress can be prevented, and disconnection of the electrodes can be prevented, and quality can be maintained.

According to a fifth aspect of the present invention, in any one of the first to fourth aspects, the flexible sheet is adhered and fixed to the base plate with a protective film attached to a surface on the conductive layer side. After the fixing, the protective film is removed.

According to the present invention, in addition to any one of the first to fourth aspects, the flexible sheet can be adhered to the base plate while the conductive layer is protected by the protective film. Dirt and scratches can be prevented.

[0020]

Embodiments of the present invention will be described below in detail with reference to the drawings.

FIGS. 1 to 5 are views showing a method of manufacturing a liquid crystal display device according to an embodiment of the present invention.

First, the liquid crystal display device will be described prior to the description of the manufacturing method. As shown in FIG. 16 and a flexible transparent substrate 18, and a liquid crystal 20 sealed in a gap formed between the rigid transparent substrate 16 and the flexible transparent substrate 18, a so-called cell gap.

The hard transparent substrate 16 is located on the display surface side (upper side in the figure) and is made of a hard material that does not bend, such as glass or hard plastic.

On the inner surface of the hard transparent substrate 16, an IT
The transparent electrode 22 is formed by O (Indium Tin Oxide). Although not shown, a polarizing plate is adhered to the outer surface of the hard transparent substrate 16.

The flexible transparent substrate 18 is located on the back side of the display (lower side in the figure) and is made of, for example, a transparent material such as polycarbonate (PC), polyacrylate (PAr), or polyether sulfone (PES). A gas barrier layer made of ethylene vinyl alcohol (EVA) or another material, and a surface layer made of epoxy resin or the like are laminated on the front and back of the plastic film, if necessary. Is done.

On the inner side surface of the flexible transparent substrate 18, a transparent electrode
Is formed. Further, a polarizing plate (not shown) is adhered to the outer surface of the flexible transparent substrate 18, and a backlight unit (not shown) is arranged further outside the polarizing plate. The rigid transparent substrate 16 and the flexible transparent substrate 1
The polarization axes of the polarizing plates on the eight side face each other at a predetermined angle in order to obtain the polarization transmittance required for displaying visible information.

On the transparent electrodes 22 and 24, the alignment film 4
4 and 46 are formed.

As described above, the front transparent hard substrate 16 is formed of a hard material, and the rear flexible transparent substrate 18 is formed of a flexible material. It is possible to achieve a reduction in weight as compared with.

Further, by using the hard transparent substrate 16 on the front side as a hard material, it is less liable to be bent as compared with the case where both the front and back substrates are formed of a flexible material, and is easy to handle when incorporated into an electronic device. Even if a small external force is applied to the liquid crystal display device 10 from the rigid transparent substrate 16 side, no local recess is formed in the rigid transparent substrate 16 and the rigid transparent substrate 1
Flexible transparent substrate 1 made of a flexible material even if 6 is slightly recessed
8 deforms following the deformation of the hard transparent substrate 16,
It is possible to prevent color unevenness of the display surface and the generation of bubbles in the liquid crystal, and further, it is possible to prevent the first and transparent electrodes 22 and 24 from cracking, thereby preventing display defects.

A connection terminal 26 is formed on the inner surface of the hard transparent substrate 16, and the transparent electrode 22 of the hard transparent substrate 16 and the transparent electrode 24 of the flexible transparent substrate 18 are formed on the connection terminal 26, respectively. Connected. The transparent electrode 24 is formed on the flexible transparent substrate 18 by an anisotropic conductive adhesive 28 provided between the rigid transparent substrate 16 and the flexible transparent substrate 18.
From the side to the hard transparent substrate 16 side.

As described above, by providing the connection terminals 26 of the transparent electrodes 22 and 24 on the hard transparent substrate 16 on the front side having good heat resistance, it is possible to connect the drive circuit at a high thermocompression bonding temperature. For example, connection without short-circuiting by ACF (Anisotropic Conductive Film) is possible, and the number of parts and the number of connection steps can be reduced as compared with the case where heat sealing is used. In the present embodiment, a liquid crystal driving I
TCP (Tape Carrier Package) 38 with C36
Are bonded by thermocompression bonding using an ACF.

Next, a method of manufacturing the above-described liquid crystal display device 10 will be described.

The liquid crystal display device 10 is manufactured through the steps of electrode formation, printing, assembly, liquid crystal injection, and polarizing plate sticking.

In the electrode forming step, first, a flexible conductive substrate, for example, an ITO layer 30 (see FIGS. 1 and 2) is formed on the surface (one surface) by sputtering. A roll-shaped plastic film made of a material is prepared. A protective film 32 is attached to the plastic film so as to cover the ITO layer 30 (see FIGS. 1 and 2).

Next, the roll-shaped plastic film is cut, and the flexible sheet 4 corresponding to a plurality of flexible transparent substrates 16 and having a size of, for example, about A4 size.
2 (see FIGS. 1 and 2).

Next, as shown in FIGS. 1 and 2, a flexible sheet 32 is formed by using a peelable adhesive material 34 and having the same size as the flexible sheet 42 with the ITO layer 30 facing up. It is attached and fixed on the base plate 52.

The adhesive material 34 is configured such that the adhesive strength of the flexible substrate-side adhesive surface 34b is lower than that of the base plate-side adhesive surface 34a. For example, if an acrylic resin or an epoxy resin is used for the adhesive material 34, the adhesive strength of the resin will be changed to the material of the mating base plate 52 and the flexible transparent substrate 16, and the substrate base plate side adhesive surface 34a The adhesive strength to the flexible substrate-side adhesive surface 34b is lower than the adhesive strength to the adhesive.

By doing so, it is possible to reliably peel off only the flexible sheet 42 with the adhesive material 34 adhered to the base plate 52 side.

As described above, from the beginning, the base plate side adhesive surface 34a
The present invention is not limited to the case where the adhesive strength of the flexible substrate-side adhesive surface 34b to each material is changed, and at least the flexible substrate-side adhesive surface 34b is formed of a material such as acrylic resin whose adhesive strength is reduced by ultraviolet irradiation. Thus, only the flexible sheet 42 can be reliably peeled off.

The pressure-sensitive adhesive material 34 has flexibility that can follow the contraction of the flexible sheet 42. In order to follow the contraction of the flexible sheet 42, the adhesive material 34 must be made of a soft material such as an acrylic resin, for example.
The thickness is preferably about 00 μm.

By doing so, the flexible sheet 42
Can be prevented from exerting an excessive stress on the flexible sheet 42 at the time of heat shrinkage, disconnection of the transparent electrode 24 can be prevented, and quality can be maintained.

The base plate 52 is made of a non-deflectable hard material such as glass, hard plastic, or metal, so that the flexible sheet 42 can be easily positioned when processed by flowing. I have. Therefore, the size of the base plate 52 is preferably larger than the flexible sheet 32 so that the flexible sheet 42 does not protrude.

The flexible sheet 42 is attached to the base plate 52 with the protective film 32 attached, and after the flexible sheet 42 is attached, the protective film 32 is peeled off. Dirt and scratching of the layer 30 can be prevented.

On the hard transparent substrate 16 side, sputtering is performed on the surface (one surface) of the hard sheet 40 having a size of, for example, A4 size corresponding to the plurality of hard transparent substrates 16, similarly to the flexible sheet 42. Transparent conductive layer,
For example, an ITO layer 54 is formed.

Next, the flexible sheet 42 and the hard sheet 40 adhered and fixed to the base plate 52 are stored in a magazine and transported, and are subjected to photolithography, that is, as shown in FIGS. 1 (A1) and 1 (A2). , ITO layer 3 of flexible sheet 42
0 and the resist liquid 56 on the ITO layer 54 of the hard sheet 40.
Is applied, exposure is performed in a predetermined pattern as shown in FIGS. (B1) and (B2), and development is performed as shown in FIGS. (C1) and (C2). After performing the etching (as shown), (E1) and (E1)
By removing the resist solution as shown in 2),
The transparent electrodes 24 and 22 (ITO electrodes) having a predetermined pattern are formed on the flexible sheet 42 and the hard sheet 40.

Next, in the printing step, as shown in FIGS. 7F and 7F, the alignment films 46 and 44 are printed on the flexible sheet 42 and the hard sheet 40, and after firing, the alignment films 4 are formed.
A rubbing process is performed on the layers 6 and 44 to give them an orientation.

The processing up to this point is performed by storing the flexible sheet 42 in the magazine and transporting it in the same manner as the hard sheet 40 in a state where the flexible sheet 42 is adhered and fixed on the base plate 52 with the adhesive material 34.

As described above, by processing the flexible sheet 42 while fixing it on the base plate 52, it is possible to accurately position the flexible sheet 42 with reference to the base plate 52.
The processing of the flexible sheet 42 can also be automated. Also,
Since the adhesive material 34 has the flexibility to follow the contraction of the flexible sheet 42, even if the flexible sheet 42 contracts by heating, the flexible sheet 42 is subjected to an excessive stress and the transparent electrode 24 can be prevented from being disconnected.

In the assembling step, first, as shown in FIG. 9G, the sealing material 14 is printed around the respective portions of the hard sheet 40 corresponding to the substrates, and the anisotropic conductive material is applied to predetermined portions of the respective portions corresponding to the substrates. The adhesive 28 is printed. In addition, spacers 12 for keeping the cell thickness constant are dispersed and arranged on portions corresponding to the respective substrates 16 of the hard sheet 40 and fired.

The flexible sheet 42 is peeled off from the base plate 52.

In this case, since the adhesive strength of the flexible substrate-side adhesive surface 34b of the adhesive material 34 is smaller than that of the base plate-side adhesive surface 34a, only the flexible sheet 42 is reliably peeled off. When the flexible substrate-side adhesive surface 34b is formed of a material whose adhesive strength is reduced by ultraviolet irradiation, the alignment film 4
By performing the UV cleaning after the formation of 6, the film can be easily peeled off without providing another step.

Further, before or after the peeling, the connecting terminal portion facing portion 48 in the portion corresponding to each substrate of the flexible sheet 42 is provided.
Is cut and removed by shearing, die cutting, or the like, and the connection terminal portion 2 is removed.
6 can be exposed (see FIGS. 4 and 5). In this case, the peripheral portion and the space between the adjacent connection terminal portion facing portions 48 are left so that the portions corresponding to the respective substrates do not fall apart.

Next, as shown in FIG. 1H, the hard sheet 40 and the flexible sheet 42 are pressed against each other and dried to cure the sealing material 14. As a result, a plurality of liquid crystal cells before filling the liquid crystal, that is, empty cells are completed.

Then, the flexible sheet 42 and the hard sheet 40 are cut into a strip shape in which the bonded rigid transparent substrate 16 and the flexible transparent substrate 18 are arranged in a line. In this case, the cutting of the second sheet 42 is performed by using a round tooth cutter or the like so that each of the strip-shaped flexible transparent substrates 18 is
It is preferable that the outer shape be smaller than the outer shape of the flexible transparent substrate 16 in the subsequent steps.

By this cutting, the liquid crystal injection port 50 is opened, and the injection port is arranged on one side of the strip.

In the liquid crystal injection step shown in FIG. 1 (I), a plurality of empty cells arranged in a strip shape in the above step are placed at positions separated from the liquid crystal in a container having a liquid crystal storage below. Place and evacuate the container. After that, the inside of the container is returned to the atmospheric pressure with the filling port in the liquid crystal storage. Then, the liquid crystal 20 is filled in the cell by the pressure difference and the capillary phenomenon.

After sealing with a sealant, a plurality of cells arranged in a strip shape are washed.

In this case, since the connection terminal portion opposing portion 48 of the flexible transparent substrate 18 is cut off, liquid crystal does not enter this portion, thereby reducing the amount of liquid crystal 20 used and simplifying cell cleaning. I can do it. In this strip-like state, the lighting test can be efficiently performed using the connection terminal portions 26 exposed from the connection terminal portion facing portions 48 of the flexible transparent substrate 18.

Thereafter, each unit cell is cut, and the process proceeds to a polarizing plate attaching step.

In the polarizing plate attaching step, a polarizing plate is attached to the hard transparent substrate 16 and the flexible transparent substrate 18.

As described above, the flat panel type liquid crystal display device 1
Completed as 0.

The present invention is not limited to the above-described embodiment, but can be variously modified within the scope of the present invention.

For example, in the above embodiment, a plastic film is used as the flexible transparent substrate. However, the present invention is not limited to this example, and a plastic plate thicker than the film can be used.

Further, a type using a reflector instead of the backlight can be used.

Further, when coloring caused by a phase shift due to wavelength becomes a problem, a retardation plate can be used in addition to the polarizing plate.

Further, the manufacturing method of the present invention can be applied to manufacturing a flexible movable substrate on the input device side in a liquid crystal display device with an input function.

Further, a liquid crystal display device can be formed by using flexible substrates instead of the hard transparent substrate on the front side.

[Brief description of the drawings]

FIG. 1 is a schematic process diagram illustrating a method for manufacturing a liquid crystal display device according to an embodiment of the present invention.

FIG. 2 is a side view showing a state where the flexible sheet of FIG. 1 is attached to a base plate using an adhesive.

FIG. 3 is a cross-sectional view of the liquid crystal display device manufactured by the method of manufacturing the liquid crystal display device of FIG.

FIG. 4 is a plan view showing a state where the flexible sheet and the hard sheet of FIG. 1 are assembled.

FIG. 5 is a partially enlarged sectional view of FIG. 4;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Liquid crystal display device 12 Spacer 14 Sealing material 16 Hard transparent substrate 18 Flexible transparent substrate 20 Liquid crystal 22 Transparent electrode 24 Transparent electrode 26 Connection terminal part 30 ITO layer as a conductive layer 32 Protective film 34 Adhesive material 40 Hard sheet 42 Flexible Sheet 52 Base plate 54 ITO layer as conductive layer

Claims (5)

[Claims] 1. A method of manufacturing a liquid crystal display device having a hard transparent substrate having a transparent electrode provided on an inner surface thereof and a flexible transparent substrate, wherein a conductive layer for the transparent electrode is formed on one surface. Forming a flexible sheet having a size corresponding to the plurality of flexible transparent substrates by cutting a flexible material, and using a peelable adhesive material to attach the flexible sheet to the conductive layer on the front side. And affixing them on a base plate having substantially the same dimensions, and processing the conductive layer of the flexible sheet attached on the base plate to form a plurality of flexible transparent substrates corresponding to the respective flexible transparent substrates. Forming a transparent electrode having a predetermined pattern; removing the flexible sheet on which the transparent electrode is formed from the adhesive; and forming a transparent sheet on one surface of a hard sheet having a size corresponding to a plurality of the hard transparent substrates. Multiple transparent patterns with a predetermined pattern corresponding to each rigid transparent substrate Manufacturing a liquid crystal display device, comprising: forming a pole; and bonding and assembling the hard sheet and the flexible sheet each having the transparent electrode formed thereon, with the transparent electrodes facing each other. Method. 2. The method for manufacturing a liquid crystal display device according to claim 1, wherein the adhesive has a small adhesive strength between the base plate side adhesive surface and the flexible substrate side adhesive surface. 3. The method for manufacturing a liquid crystal display device according to claim 1, wherein the adhesive has at least an adhesive surface on a flexible substrate side formed of a material whose adhesive strength is reduced by ultraviolet irradiation. . 4. The method for manufacturing a liquid crystal display device according to claim 1, wherein the pressure-sensitive adhesive has a flexibility capable of following shrinkage of the flexible sheet. 5. The flexible sheet according to claim 1, wherein the flexible sheet is attached and fixed to the base plate with a protective film attached to a surface on the conductive layer side. A method for manufacturing a liquid crystal display device, comprising: