JP2001042351A - Production of liquid crystal display device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce the production time of a substrate having proper flexibility by forming a liquid crystal display device having a laminar structure in which (n) layers of liquid crystal layers (wherein (n) is an integer >=2) are held by >=n+1 and <=2n-1 sheets of flexible substrates. SOLUTION: Substrates 1A, 1B are laminated with a liquid crystal layer 6A interposed to produce a liquid crystal cell B for blue display. Then a substrate 1C and the liquid crystal cell B are laminated with the liquid crystal cell 6B interposed to constitute a green display cell G, and further, a substrate 1D and the liquid crystal cells B, G are laminated with a liquid crystal layer 6C interposed to produce a liquid crystal cell R for red display. Namely, one liquid crystal cell is first produced by using two substrates, and then a liquid crystal cell having a two-layer structure is produced by using the liquid crystal cell and another substrate. Further, a liquid crystal cell having a three-layer structure is produced by using the liquid crystal cell having a two-layer structure and another substrate. Since the liquid crystal cell is produced as two units separated from each other and then laminated, each liquid crystal cell can be separately produced in parallel processes. This reduces the production time.

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 in which a plurality of liquid crystal layers are laminated.

[0002]

2. Description of the Related Art Since a display element using a liquid crystal is thin and lightweight, various uses and improvements have been studied and developed in the field of optoelectronics.

In general, in a liquid crystal display device having a plurality of liquid crystal layers laminated, two substrates are attached to each other with a gap corresponding to the thickness of the liquid crystal layer, and a liquid crystal is injected between the substrates by vacuum injection. It was usual to stack cells prepared by filling with.

Documents disclosing this type of liquid crystal display device include Japanese Patent Application Laid-Open Nos. 10-228028 and 10-24.
No. 0171 is known. However, the production method is not specifically described. In particular, in the latter case, three liquid crystal layers are sandwiched between four glass substrates, but there is a risk of breakage in the glass substrate, and the intermediate glass substrate must be polished, thereby increasing productivity. Is low.

It is an object of the present invention to provide a manufacturing method capable of mass-producing a liquid crystal display device having a multilayer structure in a simple process at low cost.

[0006]

In order to achieve the above objects, the method of manufacturing a liquid crystal display element according to the present invention comprises filling an n-layer (n-layer) by filling a liquid crystal and bonding a substrate in the same step. Is an integer of 2 or more), and a liquid crystal display element having a laminated structure in which n + 1 or more and 2n-1 or less flexible substrates are sandwiched is formed.

In the present invention, the bonding of the substrates and the filling of the liquid crystal are performed in the same step. That is, in the step of bonding the substrates, the supplied liquid crystal is filled (stretched) between the substrates. Therefore, the time required for manufacturing can be reduced. In addition, the substrate has a suitable flexibility, so there is no risk of breakage like a glass substrate, and an electrode for applying a voltage to the liquid crystal layer may be provided on the surface of the substrate facing the liquid crystal layer. It is possible.

In the present invention, the pair of substrates opposed to each other with the liquid crystal layer interposed therebetween has a peripheral portion supported by a sealing material, a spacer interposed therebetween, or at least a display region. Is preferably bonded and supported by a resin structure. The sealing material can prevent the leakage of liquid crystal, the spacer and the resin structure can accurately maintain the gap between the substrates, and especially the resin structure can increase the strength of the liquid crystal cell that holds the liquid crystal between the substrates. it can.

In the present invention, a plurality of substrates are superposed via a liquid crystal, and are preferably bonded by heating and pressing. An adhesive layer for bonding the substrate to the substrate can be omitted. When the number of substrates is n + 1, this adhesive layer may not be used at all. Therefore, a liquid crystal layer is interposed between the substrates, so that scattering and reflection of light conventionally generated in the adhesive layer are suppressed, and an improvement in transmittance can be expected.

[0010] The bonding includes (1) a method in which n + 1 substrates are overlapped with each other via a liquid crystal between the substrates, and bonding is performed at the same time; (2) a liquid crystal layer sandwiched between the substrates is formed by at least two layers.
A method of forming a stacked cell by forming layers simultaneously, and bonding another substrate while filling one surface of the stacked cell with liquid crystal; (3) forming a plurality of liquid crystal cells having a liquid crystal layer sandwiched between the substrates; (4) forming a liquid crystal cell having a liquid crystal layer sandwiched between substrates, and filling the upper and lower surfaces of the liquid crystal cell with liquid crystal, respectively. (5) One substrate is filled with liquid crystal while another substrate is bonded to form a liquid crystal cell, and one surface of the liquid crystal cell is filled with liquid crystal while another substrate is filled. A method of repeating the bonding step and bonding n + 1 substrates,
(6) A first liquid crystal cell having a liquid crystal layer sandwiched between substrates and a second liquid crystal cell having two or more liquid crystal layers sandwiched between one or more substrates than the liquid crystal layer are manufactured. First and second
Can be used to form a liquid crystal display element including three or more liquid crystal layers by stacking the above liquid crystal cells.

In the methods (1) and (2), since a plurality of liquid crystal layers are formed simultaneously, the time required for manufacturing can be shortened, and the number of times of heating the substrate is reduced, so that the deterioration of the liquid crystal is prevented. can do. In particular, these effects are high in the method (1).

In the methods (3) to (6), first, a liquid crystal cell is formed, then another liquid crystal layer is formed, and a liquid crystal cell having a laminated structure is manufactured. In addition, since the operation of the liquid crystal cell manufactured first can be checked before starting the subsequent steps, the degree of occurrence of defective products can be easily reduced. In particular, in the method (6), the latter effect is high.

In the method (5), the substrates may be sequentially bonded to the same side of the liquid crystal cell formed first, or the substrates may be bonded to the upper and lower surfaces of the liquid crystal cell formed first. You may make it match. In the former case,
Since the liquid crystal cells are stacked in order, it is easy to manufacture a liquid crystal display element.

In each of the methods (2) to (6), since the liquid crystal cell itself has flexibility by using the flexible substrate, the liquid crystal cell and the substrate or the liquid crystal are used. The bonding with the cell is as easy as the bonding between the substrate and the substrate, and there is little possibility that air bubbles are taken in at the time of the bonding.

Various devices can be used for bonding. For example, a substrate or a liquid crystal cell can be bonded between a pair of rollers that can rotate independently of each other and that can raise the temperature while filling a liquid crystal. Alternatively, a stage capable of raising the temperature and capable of adjusting the transfer position of the substrate or the liquid crystal cell may be used. The stage may have a planar shape or a cylindrical shape.

Further, as a heating means at the time of bonding, heating by a heater, induction heating using radiant heat, heating by microwave, heating by electron beam, vibration
Various means such as ultrasonic heating using frictional heat, far-infrared heating, laser light heating, and heating by Joule heat can be used.

[0017]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of a method for manufacturing a liquid crystal display device according to the present invention will be described below with reference to the accompanying drawings.

(Structure of Liquid Crystal Display Element) FIG. 1 shows an example of a liquid crystal display element obtained by the manufacturing method according to the present invention. This liquid crystal display element is a reflection type color element, and has a structure in which three liquid crystal layers 6A, 6B, 6C are sandwiched between four opposing flexible substrates 1A, 1B, 1C, 1D. The liquid crystal layer 6A reflects blue light, the liquid crystal layer 6B reflects green light, and the liquid crystal layer 6C reflects red light.

Here, the flexible substrates 1A to 1D are transparent resin film substrates, and for example, polycarbonate (PC), polyethylene terephthalate (PET), polyethersulfone (PES) or the like can be used.

The transparent electrodes 2A, 2B, 2C, 2D, 2E,
2F is patterned in a band shape on one surface of the substrates 1A and 1D and on both surfaces of the substrates 1B and 1C. Opposing band-shaped transparent electrodes intersect each other via each liquid crystal layer, and the intersection points form each pixel. I do. The transparent electrodes 2A to 2F only need to be transparent to light having a wavelength to be reflected or transmitted.
For example, an ITO film formed by sputtering is used.

The insulating films 3A, 3B, 3C, 3D, 3E, 3
F is deposited on the opposing surface of each substrate so as to cover the transparent electrode. These insulating films 3A to 3F are transparent electrodes 2A to 2F.
And the liquid crystal layers 6A, 6B, 6C. If it is not necessary due to the characteristics of the liquid crystal display element, it can be omitted or replaced with the color filter layers 4A and 4B. Here, silicon oxide was formed as the insulating films 3A to 3F by sputtering.

The color filter layers 4A and 4B are
C, 3E and the transparent electrodes 2C, 2E. The color filter layers 4A and 4B can be omitted if they are not necessary due to the characteristics of the liquid crystal display element.
The color filter layer may be any layer as long as it does not absorb the reflected light from the liquid crystal layer therebelow (the depth in the direction of direct viewing (see the arrow A)). For example, a pigment-dispersed color resist can be suitably used. Further, the color filter layer may be formed on the opposite side of the substrate in contact with the liquid crystal layer which requires the color filter layer.

Alignment films 5A, 5B, 5C, 5D, 5E, 5
F denotes color filter layers 4A and 4B, insulating films 3A to 3F,
The film is formed so as to cover the transparent electrodes 2A to 2F.
For this alignment film, for example, polyimide or the like can be used. If the characteristic of the liquid crystal display element is not necessary, it can be omitted.

The transparent electrodes 2A to 2A are provided on the flexible substrates 1A to 1D.
2F, insulating films 3A to 3F, color filter layers 4A, 4
B, the liquid crystal layers 6A, 6B, and 6C are sandwiched by substrates (hereinafter, the flexible substrate in this state is simply referred to as a substrate) on which the alignment films 5A to 5F are appropriately formed. As the liquid crystal material, for example, a nematic liquid crystal, a smectic liquid crystal, a discotic liquid crystal, a cholesteric liquid crystal, or the like can be used. When there are n liquid crystal layers, they are sandwiched between (n + 1) substrates. However, the number of substrates is (2n-
1) It is as follows. Therefore, in the case of this example having three liquid crystal layers, the number of substrates is four or five.

The thickness of the liquid crystal layers 6A, 6B, 6C is kept constant by spacers or fixed spacers 8. As the spacer, a material made of silica, divinylbenzene resin, acrylic resin, or the like can be used, and the particle size may be appropriately selected according to the gap between the substrates. Here, the fixed spacer refers to a spacer whose surface is covered with a thermoplastic resin or the like and which can be fixed to a substrate by heating or the like.

A sealing wall 7 made of resin is provided between the two substrates outside the portion where the liquid crystal layer is sandwiched. The seal wall 7 may be any as long as it can be adhered to the substrate, and a thermosetting resin or an ultraviolet curable resin made of an epoxy resin, an acrylic resin or the like can be suitably used. Seal wall 7
A spacer may be mixed therein to keep the gap between the substrates constant.

The resin structure 9 supports a vertically opposed substrate at least in the display area of the liquid crystal display element.
For example, they are arranged in a column shape. By arranging the resin structures 9 so as to be arranged between the pixels of the liquid crystal display element, it is possible to suppress the occurrence of gap unevenness as much as possible and prevent the image quality from deteriorating.

The resin structure 9 may be any as long as it can be bonded to the substrate, and for example, any of a thermoplastic resin and a polymerizable resin can be suitably used. The thermoplastic resin, for example, polyvinyl chloride resin, polyvinylidene chloride resin,
Polyvinyl acetate resin, polymethacrylate resin,
Polyacrylate resin, polystyrene resin, polyamide resin, polyethylene resin, polypropylene resin,
Fluorinated resin, polyurethane resin, polyacrylonitrile resin, polyvinyl ether resin, polyvinyl ketone resin, polyether resin, polyvinylpyrrolidone resin, saturated polyester resin, or a mixture thereof,
Examples of the polymerizable resin include an acrylic resin and an epoxy resin. Note that by using a material such as a pressure-sensitive adhesive that exhibits an adhesive ability under pressure, it is possible to bond substrates only by applying pressure after the substrates are stacked.

Back surface of substrate 1D (surface opposite to observation side)
A light absorbing layer or a light reflecting layer may be provided in accordance with the operation mode of the liquid crystal element, or the substrate 1D may be made of a light absorbing or light reflecting material. In the case of a reflective liquid crystal display device that performs display by additive color mixture such as using selective reflection by liquid crystal cholesteric phase such as chiral nematic liquid crystal, improving the contrast by providing a light absorbing layer or using a light absorbing substrate Can be. In the case of a reflection type liquid crystal display element of a subtractive color mixture type, a light reflection layer may be provided or a light reflection substrate may be used.

(Embodiments of Manufacturing Method) Each embodiment of the manufacturing method according to the present invention will be schematically described with reference to FIGS.

FIG. 2A shows the first embodiment, in which the substrate 1
A and 1B are bonded to each other with the liquid crystal layer 6A interposed therebetween to produce a liquid crystal cell B for blue display. Next, the substrate 1C and the liquid crystal cell B are bonded to each other with the liquid crystal layer 6B interposed therebetween to form a liquid crystal cell for green display. G is produced, and the substrate 1D and the liquid crystal cells B and G are bonded together with the liquid crystal layer 6C interposed therebetween to form a liquid crystal cell R for displaying red.
Is prepared. The order of manufacturing each liquid crystal cell is arbitrary. For example, the cell B may be manufactured after the cell G is manufactured, and then the cell R may be manufactured.

The point is that one liquid crystal cell is first manufactured using two substrates, and two liquid crystal cells are manufactured using this liquid crystal cell and one substrate.
Any method may be used as long as a liquid crystal cell having a layered structure is manufactured, and a liquid crystal cell having a three-layered structure is manufactured using the liquid crystal cell having the two-layered structure and one substrate.

FIG. 2B shows a second embodiment, in which a substrate 1
A, 1B and liquid crystal layers 6A, 6C between 1C, 1D, respectively.
The liquid crystal cells B and R are formed by bonding the liquid crystal cells B and R with the liquid crystal layer 6B interposed therebetween to form the liquid crystal cell G. In the second embodiment, the production of the liquid crystal cells B and R can be performed in parallel, so that the manufacturing time can be reduced as compared with the first embodiment in which the liquid crystal cells B and R are bonded one by one.

FIG. 3A shows a third embodiment.
The substrates 1B and 1C are bonded to each other with the liquid crystal layer 6B interposed therebetween to form an intermediate liquid crystal cell G. Next, the substrates 1A and 1D are interposed between the upper and lower surfaces of the liquid crystal cell G with the liquid crystal layers 6A and 6C interposed therebetween. The liquid crystal cells B and R are simultaneously formed by bonding. In the third embodiment, since the liquid crystal cells B and R are simultaneously manufactured, the manufacturing time can be reduced as compared with the first embodiment in which the liquid crystal cells B and R are bonded one by one.

FIG. 3B shows a fourth embodiment, in which the substrate 1
A, 1B, 1C and 1D are interposed between the liquid crystal layers 6A and 6A, respectively.
B and 6C are pasted together. In the fourth embodiment, only one bonding step is required, so that the manufacturing time is further reduced.

FIG. 3C shows a fifth embodiment, in which a substrate 1
A, 1B, and 1C are simultaneously bonded to each other with the liquid crystal layers 6A and 6B interposed therebetween to form liquid crystal cells B and G, and then bonded to the lower surface of the substrate 1C with the liquid crystal layer 6C interposed therebetween. To produce a liquid crystal cell R. In the fifth embodiment, the liquid crystal cells G and R are manufactured first, and then the liquid crystal cells B and
May be produced.

In short, any method may be used as long as two adjacent liquid crystal layers are simultaneously formed to form a liquid crystal cell having a laminated structure, and then another liquid crystal layer is formed using another substrate.

FIG. 4A shows a sixth embodiment.
The substrates 1B and 1C 'are bonded together with the liquid crystal layer 6B interposed therebetween to form a liquid crystal cell G, and the substrates 1C "and 1D are bonded together with the liquid crystal layer 6C interposed therebetween to form a liquid crystal cell R. Then, a substrate 1B and a substrate 1A of a liquid crystal cell G are bonded together with a liquid crystal layer 6A interposed therebetween to produce a liquid crystal cell B. Further, the liquid crystal cells B, G and a liquid crystal cell R are laminated. "Means that an adhesive is interposed or the substrate 1C ',
By fixing the periphery of 1C "with a fixing member, the layers can be laminated.

As described above, in the manufacturing method in which the liquid crystal cell is divided into two units, and then the units are stacked,
Each liquid crystal cell can be manufactured in parallel, which not only shortens the manufacturing time, but also checks the liquid crystal cells with poor display quality before the final lamination process, thereby reducing the incidence of defective products as display elements. Can be reduced, and productivity is improved. This effect is the same in the seventh embodiment described below.

FIG. 4B shows a seventh embodiment.
The substrates 1A, 1B 'are bonded together with the liquid crystal layer 6A interposed therebetween to produce a liquid crystal cell B, and the substrates 1B ", 1C, 1
D are simultaneously bonded to each other with the liquid crystal layers 6B and 6C interposed therebetween to produce liquid crystal cells G and R. Next, the liquid crystal cell B
And the liquid crystal cells G and R are stacked. The substrates 1B 'and 1B "can be laminated by interposing an adhesive or by fixing the periphery of the substrates 1B' and 1B" with a fixture.

(First Embodiment) Next, details of the first embodiment, that is, a method of attaching substrates one by one as shown in FIG. 2A will be described.

First, ITO is sputtered on a flexible substrate to form an ITO film. Thereafter, a stripe-shaped transparent electrode is formed by a photolithography process. Of these, the outer substrates 1A and 1D are provided on at least one side,
B and 1C have electrodes patterned on both surfaces.

This substrate may have an insulating film 3A to 3A on one or both sides which are bonded together via a liquid crystal layer, if necessary.
F, the alignment films 5A to 5F are coated. FIG. 5 shows the substrate 1B
Is shown as viewed from below. In the first embodiment, an insulating film, and if necessary, a color filter layer and an alignment film are formed on a substrate on which a transparent electrode has been patterned. For these films, a spin coater, a die coater, or the like can be used. As for the alignment film, for example, as shown in FIG.
The flexible substrate 1 was suction-fixed on the stage 100, the die coater 101 was rolled to apply the material 5 ′, and the material 5 ′ was formed by baking at 170 ° C. for 1 hour. The material 5 'may be appropriately selected in consideration of the compatibility with the substrate 1, the fact that impurities do not flow into the liquid crystal layer, and the like. Hereinafter, the above-described thin film forming process of the insulating film, the color filter layer, the alignment film, and the like is referred to as a film forming process.

Next, a sealing wall 7, a resin structure 9, and a spacer 8 are arranged on one or both sides of the substrate to be bonded via a liquid crystal layer. Which side of the pair of substrates to be attached may be appropriately selected. The arrangement method is such that the resin structure 9 is screen-printed at least over the entire display area so that the shape of other structures is not lost, and the sealing wall 7 in which spacers are mixed in advance is dispensed or screen-printed after the resin structure 9 is arranged. The spacer or the fixing spacer 8 is arranged on another surface of the substrate so as to be spread over at least the entire display region by a spray method so as to surround the display region. It is preferable that the sealing wall 7 is treated so as to eliminate tackiness on the surface by heating or the like before bonding. By such a process, impurities can be prevented from seeping into the liquid crystal layer. When the fixing spacers are sprayed, they may be heated at an appropriate temperature and fixed to the substrate. Hereinafter, the above-described step of disposing the seal wall, the resin structure, the spacer, and the like on the substrate is referred to as an arrangement step.

As shown in FIG. 7, the substrate having undergone the film-forming step and the arranging step is heated to a plurality of pairs of heat-pressing rollers capable of rotating independently of each other so as to sandwich the substrates 1 and 1 from both sides. When a device having three liquid crystal layers is manufactured by laminating one by one using a laminating device having 10 so as not to entrap bubbles, this process is repeated three times. Hereinafter, this step is referred to as a bonding step.

The outline of the apparatus used in the bonding step is as follows. A pair of transport rollers 111 and 11 that rotate around a direction perpendicular to the traveling directions C and C ′ for transporting and aligning the substrate.
2, and a plurality of heat-pressing roller pairs 110 that rotate around a direction orthogonal to the traveling direction C, which can rotate independently so that a plurality of substrates or liquid crystal cells can be sandwiched from both sides at once. A liquid crystal fixed-quantity discharger for supplying a fixed amount of liquid crystal material onto the substrate at a position X immediately before being wound around the heating and pressing roller pair 110 may be provided. The pressure roller pair 110 may have a mechanism for pressing each roller against the substrate surface by air pressure, spring pressure, or the like in order to press the substrate against the pressure. Further, the conveying roller pairs 111 and 112 and the heating and pressing roller pair 110 may be integrally unitized, and a guide member for guiding the substrates 1 and 1 in the direction of arrow C may be provided.

Further, in order to prevent air bubbles from being mixed into the liquid crystal layer at the time of bonding, it is desirable that the opposing substrates always have a predetermined angle or more at the bonding position. Therefore, the bonding apparatus has a member that lifts a bonding end portion of one substrate. Further, in the case where the upper and lower substrates are bonded to each other while sealing the liquid crystal in this way, the incorporation of bubbles into the gap between the substrates is not preferable from the viewpoint of display performance and reliability of the device. Therefore, it is preferable that the bonding step be performed under reduced pressure in a vacuum chamber or the like.

The order in which the substrates are bonded may be such that the substrates 1C, 1B, 1A and the substrates are sequentially stacked upward from the substrate 1D, or conversely, the substrates 1B, 1C, 1
D may be sequentially overlapped.

Each substrate is transported in the directions of arrows C and C 'by transport roller pairs 111 and 112. Preferably, the substrates are aligned using a marker or the like.

The substrates transported and aligned by the transport roller pairs 111 and 112 are bonded by the pressure roller pair 110. When bonding the upper and lower substrates, a liquid crystal material is dropped on one of the substrates. Heat-press roller pair 1
The liquid crystal is simultaneously filled between the upper and lower substrates while the gap is being set using the step 10, and the liquid crystal is sequentially expanded (extended).
The substrates are bonded as described above. At this time, a seal wall 7 and a resin structure 9 for preventing leakage of the liquid crystal after bonding are formed on one of the upper and lower substrates. The pair 110 is simultaneously crushed to a predetermined gap and serves to bond the upper and lower substrates.

When a resin that can be bonded without heating is selected as the material of the seal wall 7 and the resin structure 9 in the above-described arrangement step, the temperature of the thermocompression roller pair 110 does not need to be increased. The means for heating the substrate for bonding is
Heating by heating wire, induction heating, heating by microwave irradiation, heating by electron beam irradiation, friction heating by ultrasonic waves, heating by far infrared irradiation, heating by laser irradiation,
Heating by Joule heat by passing an electric current through the transparent electrode and a heating method using these together can be selected. When heating is required at the time of bonding, it is necessary to heat the substrate and the liquid crystal cell so that the temperature becomes uniform so as not to cause warpage or pixel shift.

Each substrate becomes an electrode terminal for connecting to a drive circuit by shifting the position of each liquid crystal layer or changing the shape of the substrate so that control signal lines can be easily connected after bonding. The structure may be stepwise so that the portion is exposed for each layer. Note that it is preferable that the electrode terminal portion of each substrate is not provided with a resin structure or a sealing wall, is not supplied with liquid crystal, and is not bonded. Further, by taking into account the bonding so that the displacement of the pixel from another substrate or the liquid crystal cell falls within half a pixel, it is possible to avoid the deterioration of the image quality of the display element.

After bonding the four substrates 1A to 1D,
If necessary, the sealing wall 7 and the resin structure 9 may be cured by heating or ultraviolet irradiation.

When forming n liquid crystal layers, the bonding step is repeated n times. According to such a method, it is possible to obtain a liquid crystal display element in which pixel shift in the stacking direction is minimized by a simple device.

(Second Embodiment) Next, details of the second embodiment will be described. In the second embodiment, as shown in FIG. 2B, in a three-layer liquid crystal layer and a four-substrate configuration, first, two liquid crystal cells B and R sandwiching the upper and lower liquid crystal layers 6A and 6C are connected. A liquid crystal cell G is formed in which a pair of liquid crystal cells are laminated and then the two liquid crystal cells are bonded together to sandwich an intermediate liquid crystal layer 6B.
This is a method for producing

First, stripe-shaped transparent electrodes 2A to 2F are formed on flexible substrates 1A to 1D, and the respective substrates are subjected to the film deposition step and the arrangement step. The details of each step are the same as in the first embodiment.

Thereafter, a pair of substrates 1A, 1B and 1C,
1D is attached to the liquid crystal layer 6 using the bonding apparatus shown in FIG.
A and 6C are attached to each other while being filled to form two liquid crystal cells. FIG. 8 shows a case where the substrates 1A and 1B sandwiching the liquid crystal layer 6A are bonded together. Although a film is formed on the back surface of the substrate 1B, it is not shown in FIG.

This bonding apparatus is composed of a flat stage 12
By fixing one end of the substrates 1A and 1B on the rod 121 on the rod 121 and performing positioning, and sliding the plane stage 120 in the direction of arrow C, the substrates 1A and 1B are heated by the heat-pressing roller 122 whose position is fixed. It is bonded by bonding while filling the liquid crystal layer 6A between the substrates 1A and 1B. The plane stage 120 has a function of fixing the substrate 1A by vacuum suction and heating. The flat stage 120 is fixed in position, and the heating and pressing roller 122 is rolled (moved while rotating) in the direction opposite to the arrow C, or both the flat stage 120 and the roller 122 are moved in opposite directions. You may.

In order to prevent air bubbles from being mixed during bonding, it is desirable that the opposing substrate 1A always have a predetermined angle or more with respect to the substrate 1B on the flat stage 120 at the time of bonding. A member for lifting the part is provided. Furthermore, the incorporation of air bubbles into the gap between the substrates is not preferable in terms of display performance and reliability of the device. For this purpose, the bonding step may be performed under reduced pressure in a vacuum chamber or the like, as described in the first embodiment. When it is difficult to vacuum-hold a large substrate by installing the apparatus under reduced pressure, it is also possible to mechanically hold the peripheral portion of the substrate.

As described above, the substrates 1A, 1B and 1C, 1
After two liquid crystal cells sandwiching each of the liquid crystal layers 6A and 6C are prepared in D, the two liquid crystal cells are bonded using a bonding apparatus shown in FIG. 8 while filling the liquid crystal layer 6B therebetween.

In the second embodiment, two liquid crystal cells can be manufactured in parallel, and as in the first embodiment,
The manufacturing time can be reduced compared to the method of laminating one layer at a time. Note that the second embodiment can be implemented using the bonding apparatus shown in FIG.

(Third Embodiment) Next, a third embodiment will be described. In the third embodiment, as shown in FIG. 3A, in a three-layer liquid crystal layer and a four-substrate configuration, first, a liquid crystal cell G sandwiching a central liquid crystal layer 6B is manufactured.
Next, a method of bonding substrates 1A and 1D to upper and lower surfaces of a liquid crystal cell G with liquid crystal layers 6A and 6C interposed therebetween is used.

First, stripe-shaped transparent electrodes 2A to 2F are formed on flexible substrates 1A to 1D, and the respective substrates are subjected to the film deposition step and the arrangement step. The details of each step are the same as in the first embodiment.

Thereafter, a pair of substrates 1B and 1C are bonded together while filling the liquid crystal layer 6B using a bonding apparatus shown in FIG. FIG. 9A shows this bonding step, in which the substrate 1C is held by vacuum suction on a flat stage 130 having heating means, and the substrate 1B is suction-held by a cylindrical stage 135 having heating means. . The flat stage 130 is movable in the direction of arrow C, and the cylindrical stage 135 is rotatable in the direction of arrow C ′ on the bonding position Y. Cylindrical stage 1
Reference numeral 35 sucks and holds the substrate 1B by a large number of suction holes 136 formed on the outer peripheral surface thereof, and sequentially releases suction at the bonding position Y. Further, an appropriate amount of liquid crystal is supplied from a dispenser or the like at the position X.

Next, as shown in FIG. 9B, the lowermost substrate 1D is suction-held on the flat stage 130, and
D, the already prepared liquid crystal cell G is superimposed on D, and the uppermost substrate 1A is sucked and held on the cylindrical stage 135.
Bonding is performed while filling the liquid crystal layers 6C and 6A therebetween. An end of the liquid crystal cell G is held by a movable holder 137, and is held at a liquid crystal supply position X so as to keep a predetermined distance and an angle from the substrate 1D.

The flat stage 130 is fixed in position, and the cylindrical stage 135 is rolled (moved while rotating) in the direction opposite to the arrow C, or both the flat stage 130 and the cylindrical stage 135 are inverted. It may be moved in the direction. The measures and the heating means for preventing air bubbles from being mixed into the liquid crystal layer are the same as in the first and second embodiments. Further, the third embodiment can be implemented using the bonding apparatus shown in FIGS. 7 and 8, and conversely, the first and second embodiments can be implemented using the bonding apparatus shown in FIG. It is also possible to carry out.

Note that, as shown in FIG. 9B, when bonding is performed using a liquid crystal cell including two or more substrates and having a liquid crystal layer between the substrates, the liquid crystal cell is compared with a single substrate. Since the flexibility tends to be poor, the resin structure immediately before the bonding and before the curing is completed is easily shifted from its original position due to the elasticity of the liquid crystal cell. Therefore, in the case where the liquid crystal cells are bonded while being bent in this manner, it is preferable that the resin structures are provided as densely as possible so that no displacement occurs.

(Fourth Embodiment) Next, a fourth embodiment will be described. In the fourth embodiment, as shown in FIG. 3B, four substrates are simultaneously bonded with each liquid crystal layer interposed therebetween.

First, the transparent electrodes 2A to 2F in the form of stripes are formed on the flexible substrates 1A to 1D, and the substrate is subjected to the film-forming step and the arranging step. The details of each step are the same as in the first embodiment.

Thereafter, as shown in FIG. 10, each of the substrates 1A to 1D is passed through a bonding apparatus having a first pressure roller pair 141, a second pressure roller pair 142, a heat pressure roller pair 143, and a transport roller pair 144. And stick them together. Each substrate is transported after being aligned by a pair of transport rollers (not shown) installed on the upstream side in each transport direction D ′, and a predetermined amount of liquid crystal is supplied from each die coater 145.

Each of the roller pairs 141 to 144 moves the substrate with an arrow D
The substrate is rotated so as to be transported in the direction, and the pressure applied to each substrate is adjusted by a spring pressure or an air pressure of an air cylinder.

The fourth embodiment can be manufactured as shown in FIG. This bonding apparatus is the same as the apparatus shown in FIG. 8, holding the substrate 1D by suction on the flat stage 120, stacking the substrate 1C with the liquid crystal layer 6C interposed therebetween, and further interposing the liquid crystal layers 6B and 6A. The substrates 1B and 1A are overlapped with each other, and pressed by a heat-pressing roller 122 to simultaneously bond the four substrates while filling the liquid crystal layer between them. The substrates are aligned at the front end in the direction of arrow C, and the rear ends are bonded together while being held by the movable holder 125.

In the fourth embodiment, an example in which four substrates are simultaneously bonded while filling three liquid crystal layers has been described. However, the present invention is not limited to this configuration, and (n +
1) The substrates can be bonded at the same time, which is efficient.

(Fifth Embodiment) Next, a fifth embodiment will be described. In the fifth embodiment, as shown in FIG. 3C, in a three-layer liquid crystal layer and a four-substrate configuration, first, liquid crystal cells B and G sandwiching the liquid crystal layers 6A and 6B are manufactured. Next, the liquid crystal layer 6C is interposed between the lower surface of the substrate 1C and the substrate 1D.
Is a method of bonding.

First, stripe-shaped transparent electrodes 2A to 2F are formed on the flexible substrates 1A to 1D, and each of the substrates is subjected to the film forming step and the arranging step. The details of each step are the same as in the first embodiment.

Thereafter, the substrates 1A, 1B and 1C are simultaneously bonded while filling the liquid crystal layers 6A and 6B therebetween. As the bonding device, any of the devices shown in FIGS. 7, 8, 9 and 10 may be used. For example, when using the apparatus shown in FIG. 10, as shown in FIG. 12, three substrates 1A, 1B, and 1C are
43, 144 and the liquid crystal layers 6A, 6 between the substrates.
Attach while filling B.

Alternatively, when the apparatus shown in FIG. 8 is used, as shown in FIG. 13, three substrates 1A, 1B,
1C is bonded between the flat stage 120 and the heat-press roller 122 while filling the liquid crystal layers 6A and 6B.

Next, the liquid crystal cell manufactured as described above and the substrate 1D are bonded together while filling the liquid crystal layer 6C therebetween.
As the bonding device, any of the devices shown in FIGS. 7, 8, 9 and 10 may be used.

(Sixth Embodiment) Next, a sixth embodiment will be described. In the sixth embodiment, as shown in FIG. 4A, in a three-layer liquid crystal layer and a five-substrate configuration, first, liquid crystal cells G and R sandwiching the liquid crystal layers 6B and 6C are manufactured. Next, on the upper surface of the substrate 1B, with the liquid crystal layer 6A interposed, the substrate 1A
Paste. Further, the liquid crystal cell R and the liquid crystal cells B and G
Are stacked.

First, stripe-shaped transparent electrodes 2A to 2F are formed on the flexible substrates 1A to 1D, and each of the substrates is subjected to the film forming step and the arranging step. The details of each step are the same as in the first embodiment. However, no film is formed on one side of the substrates 1C ′ and 1C ″.

Thereafter, the substrates 1B, 1C 'and 1C ", 1
The liquid crystal cells G and R are fabricated by bonding D while filling the liquid crystal layers 6B and 6C therebetween. As the bonding device, any of the devices shown in FIGS. 7, 8, 9 and 10 may be used. For example, the device shown in FIG. 9 can be suitably used.

Next, a liquid crystal cell B is manufactured by bonding the substrates 1B and 1A of the liquid crystal cell G manufactured as described above while filling the liquid crystal layer 6A therebetween. Also in this case, any of the devices shown in FIGS. 7, 8, 9 and 10 may be used as the bonding device.

Further, the liquid crystal cell R and the liquid crystal cells B and G are stacked. The lamination is performed by bonding the substrates 1C 'and 1C "with an adhesive or by fixing the periphery of the substrates 1C' and 1C" with a fixture.

(Seventh Embodiment) Next, a seventh embodiment will be described. In the seventh embodiment, as shown in FIG. 4B, in a three-layer liquid crystal layer and a five-substrate configuration, first, a liquid crystal cell B sandwiching a liquid crystal layer 6A, a liquid crystal layer 6B,
In this method, liquid crystal cells G and R sandwiching 6C are formed, and then liquid crystal cell B and liquid crystal cells G and R are stacked.

First, the transparent electrodes 2A to 2F in the form of stripes are formed on the flexible substrates 1A to 1D, and the substrates are subjected to the film-forming step and the arranging step. The details of each step are the same as in the first embodiment. However, no film is formed on one side of the substrates 1B ′ and 1B ″.

Thereafter, the substrates 1A and 1B 'are sandwiched between the liquid crystal layer 6
A liquid crystal cell B is prepared by bonding together while filling A.
At the same time, the substrates 1B ", 1C, and 1D are attached to each other while filling the liquid crystal layers 6B and 6C therebetween, and the liquid crystal cells G and R
Is prepared. The bonding device is shown in FIGS.
Any of the devices shown in FIG. For example, the device shown in FIG. 9 can be suitably used.

Next, the liquid crystal cells G and R and the liquid crystal cell B are stacked. The lamination is performed by bonding the substrates 1B ′ and 1B ″ with an adhesive or by fixing the periphery of the substrates 1B ′ and 1B ″ with a fixture.

(Other Embodiments) The method of manufacturing a liquid crystal display device according to the present invention is not limited to the above embodiments, but may be variously modified within the scope of the invention.

In particular, the shape of the electrodes formed on each substrate,
The presence or absence of the pattern, the insulating film, the alignment film, and the like, and the material are arbitrary.

In each of the embodiments described above, a liquid crystal display device having three liquid crystal layers laminated is described as an example. However, the present invention is not limited to this, and a liquid crystal display device having more than three liquid crystal layers laminated may be used. I do not care. For example, in the first embodiment, five substrates are sequentially bonded to laminate four liquid crystal layers, and in the second embodiment, a liquid crystal cell having one liquid crystal layer and a liquid crystal cell having two liquid crystal layers are laminated. A liquid crystal cell is used. In the third embodiment, substrates are bonded to the upper and lower surfaces of a liquid crystal cell having a laminated structure having two liquid crystal layers. In the fourth embodiment, four layers of liquid crystal are formed using five substrates. Layers are formed simultaneously, and in the fifth to seventh embodiments, 2
By using a liquid crystal cell having a three-layer structure instead of a liquid crystal cell having a layer structure, in each embodiment, a liquid crystal display element in which four liquid crystal layers are sandwiched between five substrates can be provided.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view showing a liquid crystal display device obtained by a manufacturing method according to the present invention.

FIG. 2A is a schematic explanatory diagram of a first embodiment, and FIG. 2B is a schematic explanatory diagram of a second embodiment.

3A is a schematic explanatory diagram of a third embodiment, FIG. 3B is a schematic explanatory diagram of a fourth embodiment, and FIG. 3C is a schematic explanatory diagram of a fifth embodiment.

FIG. 4A is a schematic explanatory diagram of a sixth embodiment, and FIG. 4B is a schematic explanatory diagram of a seventh embodiment.

FIG. 5 is a plan view showing a substrate subjected to a film forming step.

FIG. 6 is an explanatory view of a film forming step.

FIG. 7 is an explanatory view showing a bonding step in a bonding apparatus as a first example.

FIG. 8 is an explanatory view showing a bonding step in a bonding apparatus as a second example.

FIG. 9 is an explanatory view showing a bonding step in a bonding apparatus as a third example.

FIG. 10 is an explanatory view showing a bonding step in a bonding apparatus as a fourth example.

FIG. 11 is an explanatory view showing another bonding step in the bonding apparatus as the second example.

FIG. 12 is an explanatory view showing another bonding step in the bonding apparatus as the fourth example.

FIG. 13 is an explanatory view showing still another bonding step in the bonding apparatus as the second example.

[Explanation of symbols]

 B, G, R Liquid crystal cells 1A to 1D Substrate 6A, 6B, 6C Liquid crystal layer 7 Seal wall 8 Spacer 9 Resin structure 110, 141 to 144 Roller pair 120, 130 Planar stage 122 Heating Crimping roller 135: Cylindrical stage

 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor Jun Yamada 2-3-1, Azuchicho, Chuo-ku, Osaka-shi, Osaka F-term in Osaka International Building Minolta Co., Ltd. 2H089 HA32 LA07 MA04Y NA22 NA41 NA53 NA56 NA58 NA60 QA11 QA12 QA13

Claims (24)

[Claims] 1. An n-layer (n is an integer of 2 or more) liquid crystal layer is formed into n + 1 or more and 2n-1 or less flexible substrates by performing liquid crystal filling and substrate bonding in the same step. A method for manufacturing a liquid crystal display element, comprising forming a liquid crystal display element having a laminated structure sandwiched between substrates. 2. The method according to claim 1, wherein the number of the flexible substrates is n + 1. 3. The method according to claim 1, wherein the three liquid crystal layers are sandwiched between four flexible substrates. 4. The method according to claim 1, wherein a sealing material is provided between a pair of substrates facing each other with each liquid crystal layer interposed therebetween. 5. The method according to claim 4, wherein the sealing material is formed in an annular shape around the pair of substrates. 6. The method for manufacturing a liquid crystal display device according to claim 1, wherein a spacer is sandwiched between a pair of substrates facing each other with each liquid crystal layer interposed therebetween. . 7. The spacer according to claim 6, wherein the spacer is a fixed spacer in which spacer particles are covered with a resin material.
The manufacturing method of the liquid crystal display element described in. 8. The liquid crystal display device according to claim 1, wherein a pair of substrates facing each other via each liquid crystal layer is bonded and supported by a resin structure at least in a display area. 7. The method for manufacturing a liquid crystal display element according to claim 4 or 6. 9. The device according to claim 1, wherein an electrode is provided on a surface of each substrate facing the liquid crystal layer. A method for manufacturing a liquid crystal display device according to claim 7. 10. The method according to claim 1, wherein n + 1 substrates are overlapped with each other with a liquid crystal layer interposed between the substrates and bonded together. 10. The method for manufacturing a liquid crystal display device according to claim 6, 7, 8, or 9. 11. A laminated cell is formed by simultaneously forming at least two liquid crystal layers sandwiched between substrates to form a laminated cell, and further, another substrate is bonded while filling one surface of the laminated cell with liquid crystal. The method for manufacturing a liquid crystal display element according to claim 1, 2, 3, 4, 5, 5, 6, 7, 8, or 9. 12. The liquid crystal display device according to claim 1, wherein a plurality of liquid crystal cells having a liquid crystal layer sandwiched between substrates are formed, and the plurality of liquid crystal cells are bonded together while filling a liquid crystal therebetween. 10. The method for manufacturing a liquid crystal display device according to claim 3, claim 4, claim 5, claim 5, claim 6, claim 7, claim 8, or claim 9. 13. A liquid crystal cell in which a liquid crystal layer is sandwiched between substrates, and the substrates are bonded to each other while filling the upper and lower surfaces of the liquid crystal cell with liquid crystal. 2. The method for manufacturing a liquid crystal display device according to claim 2, claim 3, claim 4, claim 5, claim 5, claim 6, claim 7, claim 8, or claim 9. 14. A process in which one substrate is filled with liquid crystal and another substrate is attached to form a liquid crystal cell, and a step of attaching another substrate while filling one surface of the liquid crystal cell with liquid crystal is repeated. And wherein n + 1 substrates are attached to each other. Method for manufacturing a liquid crystal display element. 15. The method for manufacturing a liquid crystal display device according to claim 14, wherein the substrates are sequentially bonded to the same side of the liquid crystal cell formed first. 16. The liquid crystal cell according to claim 14, wherein each substrate is bonded to an upper surface and a lower surface of the liquid crystal cell formed first.
The manufacturing method of the liquid crystal display element described in. 17. A liquid crystal cell having a liquid crystal layer sandwiched between substrates and a stacked cell having two or more liquid crystal layers sandwiched between one or more substrates than the liquid crystal layer are manufactured. A liquid crystal display element including three or more liquid crystal layers is formed by laminating a liquid crystal cell and a liquid crystal display element. 10. The method for manufacturing a liquid crystal display device according to claim 7, 8, or 9. 18. The method for manufacturing a liquid crystal display device according to claim 10, wherein the bonding is performed by heating and pressing when bonding the substrates. 19. The liquid crystal display device according to claim 10, wherein the substrate or the liquid crystal cell is bonded to a pair of rollers that can rotate and raise the temperature independently while filling the liquid crystal with the liquid crystal. , Claim 13, Claim 14, Claim 1
19. The method for manufacturing a liquid crystal display device according to claim 17, 20 or 21. 20. The method according to claim 19, wherein the substrate or the liquid crystal cell is transported using the roller. 21. A substrate or a liquid crystal cell, which is bonded between a stage capable of raising the temperature and capable of adjusting the transfer position of the substrate or the liquid crystal cell and a roller capable of rotating and raising the temperature while filling the liquid crystal with the liquid crystal. 20. The method for manufacturing a liquid crystal display device according to claim 10, wherein the liquid crystal display element is formed by the method described in claim 10, 11, 12, 13, 13, 14, 15, 16, 17, or 18. 22. The liquid crystal display device according to claim 11, wherein a substrate or a liquid crystal cell is bonded between a pair of stages which can be moved independently and which can be heated while filling the substrate with a liquid crystal. 19. The method for manufacturing a liquid crystal display element according to claim 13, claim 14, claim 15, claim 15, claim 16, claim 17, or claim 18. 23. The method according to claim 21, wherein the stage has a cylindrical shape and is rotatable. 24. The liquid crystal according to claim 19, wherein one end of the substrate or the liquid crystal cell is held by a holder when three or more substrates or liquid crystal cells are simultaneously bonded. A method for manufacturing a display element.