JP2015175874A - Method for manufacturing cell type electrophoretic display device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for manufacturing a cell type electrophoretic display device, in which deformation of a film-like electrode substrate can be suppressed when a partition wall is formed.SOLUTION: The method for manufacturing a cell type electrophoretic display device aims to manufacture a cell type electrophoretic display device in which a partition wall is disposed between a first electrode substrate and a second electrode substrate disposed opposing to each other, and a display medium comprising at least one electrophoretic material is encapsulated in a plurality of cells segmented by the partition wall. The method includes: a calcination step of forming a partition wall-forming layer that is to be converted into the partition wall by calcination on a surface having a first electrode layer of the first electrode substrate, and calcining the partition wall-forming layer at a temperature higher than a glass transition temperature of a film substrate constituting the electrode substrate; and a cooling step of cooling the partition wall-forming layer to form the partition wall. At least the cooling step is carried out while the film substrate of the first electrode substrate is held horizontal.

Description

  The present invention relates to a method for manufacturing a cell-type electrophoretic display device applied to electronic paper or the like.

  An electrophoretic display device is a device that displays information by using electrophoretic migration, ie, particle movement, of an electrophoretic body (usually electrophoretic particles) in air or in a solvent. Usually, by applying an electric field between two substrates, the state of electrophoretic control is controlled, whereby a desired display is realized.

  In recent years, such an electrophoretic display device has attracted attention especially as an electronic paper. Electronic paper using an electrophoretic display device can have features such as visibility at a printed matter level, ease of information rewriting, low power consumption, and light weight.

  There are several types of electrophoretic display device structures. Among them, the cell-type structure partitioned by arranging a plurality of partition walls between a pair of substrates has poor display due to particle sedimentation and uneven distribution. In particular, since it is possible to suppress a reduction in contrast, it is used as a suitable material for electronic paper (see, for example, Patent Document 1). Such an electrophoretic display device may be referred to as a “cell-type electrophoretic display device”.

  As shown in FIG. 4, the cell type electrophoretic display device includes a pair of electrode substrates 21A and 21B facing each other and a partition wall portion 22 formed between the electrode substrates 21A and 21B. 22, a minute region 23 is partitioned. Note that the minute region 23 partitioned by the partition wall 22 is referred to as a cell or a pixel. In each cell 23, an electrophoretic body 25A, 25B to be electrophoresed or a display medium 24 such as ink containing the electrophoretic bodies 25A, 25B is sealed, and when an electric field is applied between the electrode substrates 21A, 21B, The electrophores 25A and 25B in the display medium 24 move and are pulled up to the display surface side X, whereby an image is formed.

JP 2011-175225 A

By the way, electronic paper or the like is required to have flexibility in order to achieve thinning and light weight and to enable high-quality image display even when bent. For this reason, use of a film-like electrode substrate in which an electrode layer is formed on a film substrate has been studied as an electrode substrate.
However, in the manufacturing method of the cell type electrophoretic display device, when the partition wall portion is formed on the electrode substrate, the partition wall portion forming layer patterned so as to have a desired cell shape is baked to form the partition wall portion. Where a firing step is required, when a film-like electrode substrate is used, there is a problem that the film substrate is deformed by the firing temperature and the planarity of the electrode substrate is impaired.
Hereinafter, the reason why such a problem occurs will be described.

In the manufacturing method of the cell-type electrophoretic display device, the partition wall portion is sufficiently cured, and in order to sufficiently remove impurities such as organic substances and low molecular components contained in the partition wall portion, the temperature is higher than the curing temperature of the partition wall portion. It is necessary to perform firing at a sufficient temperature for a sufficient time. This is because if the partition wall contains impurities, when the liquid display medium is filled in the cell, the impurity leaches out into the cell, and the charge balance of the display medium is lost due to the impurity, causing a problem in image display. This is because of this.
At this time, the firing temperature is usually set at a temperature higher than the glass transition temperature of the film substrate, and the electrode substrate is also heated at the above temperature simultaneously with the firing of the partition wall, thereby causing the film substrate to curl and swell. Deformation such as distortion will occur. For this reason, the flatness of the entire electrode substrate is impaired, and as a result, the cell gap becomes non-uniform and display defects occur.
Such deformation of the film substrate occurs even when a film substrate having a high glass transition temperature is used. Therefore, it is difficult to maintain the planarity of the film-like electrode substrate when the partition wall is formed.

  The present invention has been made in view of the above circumstances, and mainly provides a method for manufacturing a cell-type electrophoretic display device capable of suppressing deformation of a film-like electrode substrate at the time of forming a partition wall. Objective.

  As a result of intensive studies to solve the above-mentioned problems, the present inventor, at the time of cooling after firing, at least in the case of firing at a temperature higher than the glass transition temperature of the film substrate in the formation of the partition wall. In addition, the inventors have found that it is possible to prevent deformation of the film substrate and the entire electrode substrate by cooling in a state where the film substrate is held flat, and the present invention has been completed.

  That is, the present invention provides a first electrode substrate having a film substrate and a first electrode layer formed on one surface of the film substrate, and a second electrode layer formed on one surface of the support substrate and the support substrate. A second electrode substrate having a partition wall between the first electrode substrate and the second electrode substrate, wherein the first electrode layer and the second electrode layer are opposed to each other. A method for manufacturing a cell-type electrophoretic display device, wherein a display medium containing at least one kind of electrophoretic body is enclosed in a plurality of cells partitioned by the partition wall between an electrode substrate and the second electrode substrate. A firing in which a partition wall forming layer to be the partition wall is formed by firing on the surface of the first electrode substrate having the first electrode layer, and firing is performed at a temperature higher than the glass transition temperature of the film substrate. Process and A cooling step of cooling the partition wall forming layer to form the partition wall, wherein at least the cooling step is performed in a state where the film substrate of the first electrode substrate is held flat. A method for manufacturing a cell-type electrophoretic display device is provided.

  According to the present invention, at the time of forming partition walls for partitioning a plurality of cells, firing is performed at a temperature higher than the glass transition temperature of the film substrate with respect to the partition wall forming layer that becomes the partition walls by firing. By cooling in a state where the substrate is held flat, the film substrate can be prevented from being deformed when the partition wall is formed. As a result, the planarity of the first electrode substrate is maintained, and the plurality of cells in which the display medium is sealed can have a uniform cell gap, and a cell-type electrophoretic display device with good image display can be manufactured. it can.

  According to the present invention, it is possible to suppress the deformation of the film-like electrode substrate during the formation of the partition wall.

It is process drawing which shows an example of the manufacturing method of the cell-type electrophoretic display device of this invention. It is explanatory drawing explaining an example of the fixing method of the 1st electrode substrate in a cooling process. It is explanatory drawing explaining the other example of the fixing method of the 1st electrode substrate in a cooling process. It is a schematic sectional drawing which shows an example of a general cell-type electrophoretic display device.

  Hereinafter, the manufacturing method of the cell-type electrophoretic display device of the present invention will be described in detail. The manufacturing method of the cell-type electrophoretic display device of the present invention includes a film substrate, a first electrode substrate having a first electrode layer formed on one surface of the film substrate, and a support substrate and one surface of the support substrate. A second electrode substrate having a second electrode layer formed on the first electrode layer is disposed so that the first electrode layer and the second electrode layer face each other, and a partition wall is formed between the first electrode substrate and the second electrode substrate. A cell type in which a display medium including at least one kind of electrophoretic body is enclosed in a plurality of cells partitioned by the partition wall between the first electrode substrate and the second electrode substrate A method for manufacturing an electrophoretic display device, comprising: forming a partition wall forming layer to be the partition wall by baking on a surface of the first electrode substrate having the first electrode layer; and a glass transition temperature of the film substrate. Higher than And a cooling step of cooling the partition wall forming layer to form the partition wall, and at least the cooling step holds the film substrate of the first electrode substrate in a plane. It is performed by.

A method for manufacturing the cell-type electrophoretic display device of the present invention will be described with reference to the drawings. FIG. 1 is a process diagram showing an example of a method for manufacturing a cell-type electrophoretic display device of the present invention.
First, the 1st electrode substrate 1 with which the 1st electrode layer 12 was formed in the single side | surface of the film substrate 11 is prepared (FIG. 1 (a)). On the surface of the first electrode substrate 1 having the first electrode layer 12, a partition wall portion forming layer is formed for applying a partition wall material and partitioning a plurality of cells into a desired shape by exposure and development. 3 ′ is formed, and the partition wall forming layer 3 ′ is baked at a temperature T higher than the glass transition temperature of the film substrate 11 (FIG. 1B).
Next, the partition wall forming layer 3 ′ after firing is cooled to form partition walls 3. At this time, a load P is applied to the first electrode substrate 1 and cooling is performed in a state where the film substrate 11 is held flat (FIG. 1C).
Next, a transfer film 50 having a separately prepared adhesive layer 5 on one side is used, the adhesive layer 5 of the transfer film 50 is bonded to the top surface of the partition wall 3, and the adhesive layer 5 is applied to the top surface of the partition 3 by thermal transfer. (FIG. 1D). Subsequently, the display medium 6 is filled into the cells 4 partitioned by the partition walls 3 on the first electrode substrate 1 (FIG. 1E).
In a separate process, a second electrode substrate 2 in which the second electrode layer 14 is formed on one surface of the support substrate 13 is prepared, and the second electrode substrate 2 and the first electrode substrate 1 are connected via the adhesive layer 5. The cell-type electrophoretic display device 10 of the present invention is obtained by bonding (FIG. 1 (f)). Although not shown, normally, the outer periphery of the first electrode substrate 1 and the second electrode substrate 2 is for sealing after the second electrode substrate 2 and the first electrode substrate 1 are bonded via the adhesive layer 5. Sealed with a seal.
In addition, FIG.1 (b) is a baking process and FIG.1 (c) is a cooling process.

In the manufacture of the cell-type electrophoretic display device, when the partition wall partitioning the cell is formed on the electrode substrate, in order to sufficiently cure the partition wall and sufficiently remove impurities contained in the partition wall, It is necessary to perform firing at a temperature higher than the curing temperature for a sufficient time.
However, since the firing temperature at this time is higher than the glass transition temperature of the film substrate constituting the electrode substrate, the film substrate is deformed such as curl, undulation, distortion, etc. The problem arises that the performance is impaired.
Even when a film substrate having a high glass transition temperature is used, such deformation of the film substrate can occur.

As a result of intensive studies by the inventor on the above problem, the film substrate was held flat at least in the cooling step even when baking was performed at a temperature higher than the glass transition temperature of the film substrate in the baking step. It has been found that the film substrate can be prevented from being deformed when the partition wall is formed by cooling in the state.
In addition, since the partition wall is formed on the electrode substrate that is kept flat by this method, a plurality of cells in which the display medium is sealed can have a uniform cell gap, and a cell with good image display. Type electrophoretic display device can be manufactured.

  Hereinafter, each process of the manufacturing method of the cell-type electrophoretic display device of the present invention will be described.

1. Firing step In the firing step of the present invention, a partition wall forming layer that becomes a partition wall portion is formed by firing on the surface of the first electrode substrate having the first electrode layer, and is fired at a temperature higher than the glass transition temperature of the film substrate. It is a process to do.

(1) 1st electrode substrate First, the 1st electrode substrate used in this process is explained. The first electrode substrate used in this step has a film substrate and a first electrode layer formed on one surface of the film substrate. The first electrode substrate may be transparent or opaque, but may be transparent when the first electrode substrate is used on the display surface side of the cell-type electrophoretic display device. preferable.
The first electrode substrate used in the present invention may be an off-the-shelf product or a formed one.

(A) Film substrate The material of the film substrate is not particularly limited as long as it is a film made of resin, and may be transparent or opaque.
The resin used for the film substrate is preferably a resin having a glass transition temperature of 50 ° C. or higher, and more preferably a resin having a glass transition temperature of 70 ° C. or higher. This is because if the glass transition temperature is too low, the thermal stability of the film substrate is low, and the use temperature range of the obtained cell-type electrophoretic display device may be narrowed. In addition, as an upper limit of the glass transition temperature of resin used for a film substrate, it is preferable that it is 200 degrees C or less.
Examples of such resins include polypropylene (PP), polyethylene terephthalate (PET), polyethylene naphthalate (PEN), polyethersulfone (PES), polyethylene (PE), polycarbonate (PC), acrylic, and polyvinyl chloride. , Polyvinyl alcohol, polyimide, polyetherimide, polyether ether ketone, polyether ketone, polyphenylene sulfide, liquid crystal polymer, epoxy resin, silicone resin, phenol resin and the like. Among these, polyethylene terephthalate (PET) is preferable. This is because the versatility is high and the manufacturing cost of the cell type electrophoretic display device can be reduced.
In addition, when the 1st electrode substrate used for this process is used for the display surface side of a cell-type electrophoretic display device, the resin has transparency.
In addition, as an opaque film substrate, a film in which a metal film is deposited on the surface of the film substrate made of the resin facing the surface on which the first electrode layer is formed, a film obtained by kneading a dye, pigment, or the like in the resin described above. What was made into the shape can be used.

  The thickness of the film substrate is preferably in the range of 10 μm to 1 mm, and preferably in the range of 20 μm to 300 μm. If the thickness of the film substrate is smaller than the above range, the strength as the first electrode substrate may not be obtained and may be easily damaged. On the other hand, if the thickness is larger than the above range, the weight of the first electrode substrate may be increased. This is because it may become heavy and handling may be inconvenient or cost may increase.

  Moreover, when the said film substrate has transparency, it is preferable that the transmittance | permeability in visible region is 80% or more, and it is more preferable that it is 90% or more. This is because, when the transmittance of the film substrate is in the above range, it is possible to prevent a decrease in display luminance or the like when the first electrode substrate is used on the display surface side of the cell type electrophoretic display device. In addition, the transmittance | permeability of a transparent base material can be measured by JISK7361-1 (the test method of the total light transmittance of a plastic-transparent material).

(B) First electrode layer The first electrode layer may be transparent or opaque, but when the first electrode substrate is disposed on the display side surface, the first electrode layer is also transparent. It is preferable that the first electrode layer is a transparent electrode layer.

The material of the transparent electrode layer is not particularly limited as long as it is a conductive material having transparency. For example, indium tin oxide (ITO), indium zinc oxide (IZO), tin oxide, zinc oxide, indium oxide , Conductive oxides such as aluminum zinc oxide (AZO), metals such as Au, Ni, and Ag, conductive polymers such as polyaniline, polyacetylene, polyalkylthiophene derivatives, polysilane derivatives, carbon nanotubes, graphene, etc. Can do.
In addition, it is preferable that the transmittance | permeability in the visible light area | region of a transparent electrode layer is the same as the transmittance | permeability in the visible light area | region of the film substrate which has transparency mentioned above.

  The material of the electrode layer when the first electrode layer is opaque is, for example, a metal such as Cu, Ag, Au, Pt, Al, Cr, Co, or Sn, or APC (an alloy containing Ag, Pd, or Cu). The above-mentioned metal alloys such as MAM (a multilayer metal film in which a molybdenum film, an aluminum-neodymium alloy film, and a molybdenum film are laminated in this order) are included.

The thickness of the first electrode layer is not particularly limited as long as the conductivity can be ensured, but it is preferably within the range of 15 nm to 10 μm.
When the first electrode layer is a transparent electrode layer, the first electrode layer preferably has a thickness of 50% to 99%, and more preferably has a thickness of 70% to 95%. Preferably there is. The transmittance is a value measured using, for example, a spectrophotometer UV3100PC manufactured by Shimadzu Corporation.
If the thickness of the first electrode layer is less than the above range, it is difficult to form the first electrode layer with a uniform thickness, while the thickness of the first electrode layer is within the above range. In the case of exceeding, the material used for the film formation of the first electrode layer increases, and the manufacturing cost increases.

  The first electrode layer may have a pattern shape, may cover all of one surface of the film substrate, and can have a shape of a pixel electrode in a general display device. When the first electrode substrate is used on the side opposite to the display surface of the cell type electrophoretic display device, the first electrode layer usually has a display image pattern as a pixel electrode.

  The method for forming the first electrode layer is not particularly limited as long as it can be formed to have a desired thickness and pattern, and a general electrode film forming method can be used. . Specifically, PVD methods such as vacuum vapor deposition, sputtering, and ion plating, CVD, methods of applying a conductive paste, inkjet, screen printing, flexographic printing, plating, and the like can be given. In particular, when a transparent electrode layer is formed as the first electrode layer, it is preferable to use a sputtering method, a vacuum evaporation method, or a CVD method.

(C) Others The surface of the first electrode substrate opposite to the surface on which the first electrode layer is formed may have a further functional layer. When the first electrode substrate is used on the display surface side of the cell-type electrophoretic display device, as the functional layer, for example, a barrier layer, a barrier layer such as a transparent inorganic vapor deposition film, an ultraviolet cut film, an antiglare layer (AG layer) A scratch prevention layer (HC layer), an antireflection layer (AR layer), or the like is used. When the first electrode substrate is used on the non-display surface side of the cell-type electrophoretic display device, for example, a barrier layer such as a barrier film or a transparent inorganic vapor deposition film, an ultraviolet cut film, or the like is used as the functional layer. .

(2) Partition wall forming layer The partition wall forming layer formed in this step becomes a partition wall by firing, and has a desired pattern for partitioning cells by the partition wall and determining the cell shape. It is.
The material for the partition wall forming layer in this step may be any material as long as it can form a partition wall having a desired height, and can be appropriately selected according to the method for forming the partition wall forming layer described later. Specific examples of the material include a thermosetting resin, a photosensitive resin, and a dry film resist made of a photosensitive resin. Among these, a dry film resist made of a photosensitive resin is preferable because a partition wall forming layer for forming a cell having a desired shape can be easily formed using a photolithography method. The photosensitive resin is preferably a negative photosensitive resin, and examples thereof include a photosensitive polyimide resin, an acrylic resin, a photosensitive phenol resin, a photosensitive epoxy resin, a novolac resin, and a melamine resin.

The method for forming the partition wall forming layer is not particularly limited as long as it is a method capable of forming a cell having a desired shape. For example, a dry film resist film is laminated on the entire surface of the first electrode substrate having the first electrode layer, and a photolithography method for performing exposure and development, and a partition wall portion is formed on the entire surface of the first electrode substrate having the first electrode layer A mold transfer method in which a layer material is applied and the concavo-convex plate is pressed, a printing method in which printing is performed using the material of the partition wall forming layer, and the like can be used. Also, a method of separately forming a mesh processed structure using the material of the partition wall forming layer and bonding the structure portion as a partition wall forming layer to the surface of the first electrode substrate having the first electrode layer is used. Is also possible.
In addition, it does not specifically limit about the conditions in various formation methods, It sets suitably according to the material of the partition part formation layer used. The thickness of the partition wall forming layer and the shape of the cell partitioned by the partition wall forming layer in plan view are the same as those of the partition wall and cell described in “2. Cooling step” described later. is there.

(3) Firing conditions In this step, the firing temperature at which the partition wall forming layer is fired is such that impurities contained in the partition wall forming layer can be removed and the curing reaction is accelerated to deteriorate the electrical characteristics of the display medium. For example, the temperature is preferably in the range of 80 ° C to 300 ° C, and more preferably in the range of 100 ° C to 200 ° C. The firing time is preferably in the range of 10 minutes to 120 minutes, more preferably in the range of 30 minutes to 60 minutes, although it depends on the material of the partition wall forming layer and the firing temperature.
Specifically, when the film substrate is a PET film, since the glass transition temperature is 110 ° C., the firing temperature and time in this step are within the range of the firing temperature of 120 ° C. to 250 ° C., and the firing time. It is preferably within the range of 10 minutes to 120 minutes, and in particular, the firing temperature is preferably within the range of 130 ° C. to 200 ° C., and the firing time is preferably within the range of 30 minutes to 60 minutes.

This step may be performed in a state where the film substrate of the first electrode substrate is held on a flat surface or may be performed without being held on a flat surface, but is preferably performed in a state where the film substrate is held on a flat surface. This is because in the cooling step, the first electrode substrate can be cooled in a state of being held flat in this step.
Moreover, when baking is performed with the film substrate of the first electrode substrate held flat, it is preferable that a load be applied to the first electrode substrate.
Note that a method for holding the film substrate of the first electrode substrate on a plane, a method for applying a load, and the like will be described in the section “2. Cooling step” to be described later, and thus description thereof is omitted here.

2. Cooling process The cooling process in this invention is a process of cooling the said partition part formation layer and setting it as a partition part.
Moreover, this process is performed in the state which hold | maintained the film substrate of the 1st electrode substrate in the plane.

  In this step, by cooling the film substrate of the first electrode substrate in a flat state, even if the film base material is deformed due to excessive heat applied in the above-described baking step, the cooling is performed. In this case, it is possible to improve the deformation of the film substrate by being held on a flat surface.

  In this step, holding the film substrate of the first electrode substrate in a plane means holding the film substrate so as to eliminate deformation such as curling, swell, and distortion generated on the film substrate, specifically cooling. This means that the flatness of the film substrate is held at 1000 μm or less, and it is preferable that the flatness is held at 500 μm or less. In addition, about the said flatness, it can obtain | require by the method prescribed | regulated to JISB0621.

(1) Cooling method As a cooling method in this step, any method can be used as long as the film substrate of the first electrode substrate is held flat and can be uniformly cooled, for example, with respect to the first electrode substrate. A method of directly cooling air by allowing it to stand at room temperature, such as a method of directly blowing cooling air from a cooling nozzle, a method of arranging a first electrode substrate on a cooling substrate cooled by circulating a refrigerant, a method of exposing the first electrode substrate to a low temperature state, etc. Is mentioned.

  In this step, the method of holding the film substrate of the first electrode substrate in a flat surface is not particularly limited. For example, on a flat and rigid cooling substrate such as glass, a peelable adhesive layer is interposed. The method of bonding a 1st electrode substrate, the method of applying a load to at least one direction with respect to a 1st electrode substrate, and hold | maintaining to a plane etc. are mentioned. Among them, a method is preferred in which the surface of the first electrode substrate is not in contact with other members and the film substrate is held flat by applying a load in at least one direction to the surface of the first electrode substrate. This is because, in the method of bonding to a cooling substrate or the like to hold a flat surface, if there is any contamination such as dust on the bonding surface, the film substrate may swell at the mixing location.

Although the application direction of the load to the first electrode substrate is not particularly limited, it is preferable to apply the load P from the surface direction of the first electrode substrate 1 as shown in FIG.
When applying a load from the surface direction of the first electrode substrate, the first electrode substrate 1 is suspended as shown in FIG. 3 in addition to a method in which the first electrode substrate is floated and placed on a plane and pulled in the surface direction. The method of lowering etc. is mentioned.
The application direction when applying a load in the surface direction of the first electrode substrate may be at least one direction in which the first electrode substrate can be held on a plane as shown in FIG. The load P may be applied from two directions as shown in FIG.
2 and 3 are explanatory views for explaining an example of a fixing method of the first electrode substrate, and the first electrode substrate shown in FIG. 3 is a diagram seen from a plan view.

  The magnitude of the load applied to the first electrode substrate is preferably such a size that the film substrate is not deformed or damaged by the application of the load in an environment at or above the glass transition temperature. For example, when the film substrate is a PET film, the load is preferably in the range of 0.1N to 10N in an environment of 110 ° C. or higher, which is a glass transition temperature, and more preferably 0.5N to 5N. It is preferable to be within the range.

(2) Partition Wall The partition wall formed by this step defines a cell that encloses a display medium including an electrophoretic body.
The height of the partition wall is preferably in the range of 5 μm to 100 μm, and more preferably in the range of 10 μm to 50 μm. If the height of the partition wall is smaller than the above range, the amount of the display medium filled in the cells partitioned by the partition wall decreases, and sufficient display characteristics, particularly contrast may not be obtained. On the other hand, if the height of the partition wall portion is larger than the above range, the thickness of the entire cell type electrophoretic display device may be too large, and the drive voltage may increase excessively.
Examples of the cross-sectional shape of the partition wall include a rectangle and a trapezoid.

The shape of the cells partitioned by the partition walls in plan view is not particularly limited, and may be, for example, a polygon such as a circle, a lattice, a hexagon, or a triangle.
Moreover, all the cells may have the same shape in plan view, or the shape in plan view may be different for each cell. Moreover, all the sizes of the cells may be the same or may be different for each cell.

The cells partitioned by the partition walls preferably have a high aperture ratio. This is because the area per unit cell partitioned by the partition wall is increased, so that the image display area is increased and high contrast can be obtained. Specifically, the aperture ratio is preferably 70% or more, and particularly preferably 90% or more.
At this time, as the size of the cell partitioned by the partition wall, the cell pitch is preferably in the range of 0.05 mm to 1 mm, particularly preferably in the range of 0.1 mm to 0.5 mm. The cell pitch refers to the distance between the centers of adjacent cells.

3. Arbitrary process The manufacturing method of the cell-type electrophoretic display device of the present invention may have an optional process in addition to the baking process and the cooling process described above.
Hereinafter, the arbitrary process in this invention is demonstrated.

(1) Adhesive layer formation process This invention may have the process of forming an adhesive layer in the top part surface of a partition part. By forming the adhesive layer on the top surface of the partition wall, the first electrode substrate and the second electrode substrate can be bonded via the adhesive layer, and the cell filled with the display solvent can be sealed. is there.
This step corresponds to FIG. 1D in the description of FIG. 1 described above.

The method for forming the adhesive layer on the top surface of the partition wall is not particularly limited. For example, the following method can be used.
First, an adhesive is applied to a transfer film substrate made of a polyethylene terephthalate (PET) film to form a transfer film having an adhesive layer on one side. Next, the adhesive layer side surface of the transfer film is aligned with the top surface of the partition wall, and the transfer film is only subjected to its own weight or at a temperature equal to or higher than the softening temperature of the adhesive while receiving a predetermined pressing force. Heat to peel off the transfer film. By the above method, the adhesive layer can be thermally transferred to the top surface of the partition wall.

(A) Adhesive layer The material of the adhesive used in this step is not particularly limited, but a thermoplastic resin is preferred because the adhesive layer is transferred and formed on the top of the partition wall by heating and pressing. Specifically, ethylene-vinyl acetate copolymer, thermoplastic base polymer such as polyester, polyamide, polyolefin, polyurethane, natural rubber, styrene-butadiene block copolymer, styrene-isoprene block copolymer, styrene-ethylene- A resin mainly composed of a thermoplastic elastomer such as a butylene-styrene block copolymer, a styrene-ethylene-propylene-styrene copolymer, and a tackifier resin or a plasticizer is mainly used.
Further, the adhesive may contain a silane coupling agent or the like. This is because the adhesion can be improved when the adhesive layer is thermally transferred to the top surface of the partition wall.

The softening temperature of the adhesive depends on the type of the thermoplastic resin used for the adhesive, but may be the glass transition temperature (Tg) or the melting temperature (Tm) of the thermoplastic resin used, preferably 150 ° C. or less, and 120 ° C. The following is more preferable, and 80 ° C. or lower is particularly preferable.
At this time, the softening temperature of the adhesive is preferably lower than the glass transition temperature of the film substrate in the first electrode substrate. When the softening temperature of the adhesive is higher than the glass transition temperature of the film substrate, the partition wall and the first electrode substrate are caused by shrinkage caused by shrinkage of the film substrate, waviness caused by shrinkage of the film substrate, or the like. This is because the partition wall portion may be peeled off from the first electrode substrate when the transfer film is thermally peeled.
The softening temperature of the adhesive is preferably lower than the thermal decomposition temperature of the display medium. This is because if the softening temperature of the adhesive is higher than the thermal decomposition temperature of the display medium, which will be described later, the display performance may be deteriorated due to the thermal decomposition of the display medium. Note that the thermal decomposition of the display medium means that the solvent, additive, particles, and the like contained in the display medium are volatilized and the like by firing, and the chemical properties (modes) of the display medium change.

In this step, the thickness of the adhesive layer formed on the top surface of the partition wall is preferably in the range of 1 μm to 100 μm, more preferably in the range of 1 μm to 50 μm, and particularly preferably in the range of 1 μm to 10 μm. When the film thickness of the adhesive layer is smaller than the above range, sufficient adhesive force to bond the first electrode substrate and the second electrode substrate may not be obtained. This is because the thickness of the display device increases and the drive voltage may increase too much.
The film thickness of the adhesive layer formed on the transfer film substrate is the same as the above film thickness range.

(B) Other In this step, the pressing force for transferring the adhesive layer on the transfer film to the top surface of the partition wall may be a size that can be sufficiently transferred, for example, 0.01 MPa to 0.7 MPa. In particular, the range of 0.1 MPa to 0.4 Ma is preferable. If the pressing force is smaller than the above range, the transfer of the adhesive layer from the transfer film may not be sufficiently performed. On the other hand, if the pressing force is larger than the above range, the adhesive layer may be crushed and enter the cell. Etc.

  In addition, in order to improve the adhesion between the partition wall and the adhesive layer, the partition wall is subjected to a surface treatment such as ultraviolet irradiation or plasma treatment before the adhesive layer on the transfer film is transferred to the top surface of the partition wall. Alternatively, a primer layer may be formed.

  In this step, the adhesive layer is usually transferred and formed on the tops of all the partition walls. However, as long as the effects of the present invention are obtained, the adhesive layer is transferred only on the tops of some of the partition walls. It may be formed. For example, the adhesive layer may be transferred and formed only on the peripheral partition wall.

(2) Display medium filling step The present invention may have a display medium filling step of filling the display medium into a plurality of cells partitioned by the partition walls.
This step is usually performed after the above-described adhesive layer forming step. In the description of FIG. 1 described above, FIG. 1E corresponds to this step.

The display medium used in this step includes at least one or more electrophores.
As the electrophoretic material, colored, colorless, or white inorganic pigment particles or organic pigment particles can be used.
The display medium may contain a dye, a dispersion, and the like in addition to the electrophoretic body, and various known materials can be used.

  As a method for filling the display medium, for example, the following method can be used. First, an ink as a display medium is dropped from a dispenser, an ink jet, a die coat or the like on the first electrode substrate in which an adhesive layer is formed on the top surface of the partition wall, and is surfaced by a central squeegee, a doctor blade, a doctor knife, or the like. Apply the ink so that it is uniform inside, and scrape off the excess ink that protrudes from the cell with a squeegee on both ends or a doctor blade, doctor knife, etc., and finally remove the excess ink collected on one side by the wiper By scraping, ink can be filled only in the cells.

(3) Bonding step The present invention may have a bonding step of bonding the first electrode substrate and the second electrode substrate. By this step, each cell partitioned by the partition walls can be sealed with the display medium filled in the cell. Therefore, this step is preferably performed after the above-described adhesive layer forming step and display medium filling step.

(A) Second electrode substrate The second electrode substrate in this step has a support substrate and a second electrode layer formed on one surface of the support substrate.
The second electrode substrate must be transparent when the first electrode substrate is not transparent, but the second electrode substrate is transparent when the first electrode substrate is transparent. It may be present or opaque.
In addition, the 2nd electrode substrate being transparent means that the transmittance | permeability of the support substrate mentioned later and the 2nd electrode layer shows more than a desired value.

(I) Support substrate The support substrate in the second electrode substrate may be flexible or rigid.
As the support substrate having flexibility, since the same substrate as the film substrate in the first electrode substrate described in the above-mentioned section “1. Firing step” can be used, description thereof is omitted here.
On the other hand, examples of the rigid support substrate include resin plates, soda lime glass, alkali-free glass, epoxy glass (glass epoxy), quartz glass and other glass plates, ceramics, and the like.
In addition, when the second electrode substrate is transparent, the support substrate has transparency. At this time, the transmittance in the visible light region of the support substrate is the transparency described in the section of “1. Firing step” described above. It is preferable that the transmittance is the same as that of a transparent film substrate.

  Further, as the opaque support substrate, an opaque glass substrate having a rough surface facing the surface having the second electrode layer, an opaque substrate having a metal film deposited on the surface facing the surface having the second electrode layer, An opaque resin base material in which dyes and pigments are kneaded is exemplified.

  The thickness of the support substrate is preferably in the range of 10 μm to 1 mm, particularly in the range of 50 μm to 300 μm.

  Note that the surface of the support substrate may be subjected to an antioxidant treatment by plating.

(Ii) Second Electrode Layer Since the material of the second electrode layer in the second electrode substrate can be the same as the material of the first electrode layer described in the above section “1. Firing step”, here The description in is omitted.
Further, the transmittance in the visible light region when the second electrode layer is transparent is preferably equal to the transmittance in the visible light region of the support substrate.

  In addition, the shape, thickness, formation method, and the like of the second electrode layer are the same as those of the first electrode layer described in the above-mentioned section “1. Firing step”, and thus description thereof is omitted here.

(Iii) Others An arbitrary functional layer may be provided on the surface of the second electrode substrate opposite to the surface on which the second electrode layer is formed. The example of the functional layer is the same as that described in the section “1. Firing step”, and thus the description thereof is omitted here.

Further, a sealing layer for sealing may be provided on the outer periphery of the second electrode substrate. This is because the outer periphery can be sealed by the sealing layer for sealing when the first electrode substrate and the second electrode substrate are bonded.
Examples of the material for the sealing layer for sealing include those generally used as a sealing material such as an ultraviolet curable resin, a thermosetting resin, and a heat sealant.

(B) Bonding method Although it does not specifically limit as a bonding method of a 1st electrode substrate and a 2nd electrode substrate, For example, the surface in which the 2nd electrode layer of a 2nd electrode substrate is formed, and a 1st electrode substrate It can be bonded via an adhesive layer provided on the top surface of the partition wall by facing the surface on which the partition wall is formed and adhering it with a predetermined pressing force. At this time, it is assumed that the display medium is filled in the cells partitioned by the partition walls.

(4) Other steps In addition to the steps described above, the present invention provides an electrode substrate forming step for forming the first electrode substrate and the second electrode substrate, and sealing for sealing between the first electrode substrate and the second electrode substrate. Process, a half-cut process of cutting off the other electrode substrate facing each other to expose a part of the electrode layer on one electrode substrate as a lead electrode, and a drive device installation for attaching a drive device for supplying power to the lead wiring from the outside You may have a process etc.

4). Cell-type Electrophoretic Display Device The cell-type electrophoretic display device obtained by the present invention includes a film substrate 11 and a first electrode layer formed on one surface of the film substrate 11 as shown in FIG. The first electrode substrate 1 having 12 and the second electrode substrate 2 having the second electrode layer 14 formed on one surface of the support substrate 13 and the support substrate 13 are the first electrode layer 12 and the second electrode layer 14. Are arranged so as to face each other, and have a partition wall portion 3 between the first electrode substrate 1 and the second electrode substrate 2, and the partition wall portion 3 between the first electrode substrate 1 and the second electrode substrate 2 A display medium 6 including at least one kind of electrophores is enclosed in a plurality of partitioned cells 4. The first electrode substrate 1 and the second electrode substrate 2 are bonded via an adhesive layer 5 provided on the top surface of the partition wall portion 3.

In the cell-type electrophoretic display device, at least one of the first electrode substrate and the second electrode substrate has transparency, and the electrode substrate having transparency can be the display surface side of the screen.
Further, by applying an electric field between the first electrode substrate and the second electrode substrate, the electrophoretic body contained in the display medium sealed in the cell moves and is pulled up to the display surface side, so that an image is displayed. It is formed and displayed on the display surface.

  The present invention is not limited to the above embodiment. The above-described embodiment is an exemplification, and the present invention has substantially the same configuration as the technical idea described in the claims of the present invention, and any device that exhibits the same function and effect is the present invention. It is included in the technical scope of the invention.

  Hereinafter, the present invention will be described in more detail with reference to Examples and Comparative Examples.

[Example]
(Preparation of partition wall)
A partition wall was formed on the first electrode substrate by the following method.
On the first electrode substrate in which a transparent electrode (ITO) is formed on one surface of a PET film (Toyobo Cosmo Shine, 300 mm × 400 mm × thickness 0.1 mm, glass transition point 110 ° C.), negative photosensitive A resin material (manufactured by DuPont MRC Dry Film Resist Co., Ltd., dry film resist) is laminated to a thickness of 30 μm, heated at 100 ° C. for 1 minute, and then exposed using an exposure mask ( The exposure amount was 500 mJ / cm ² ), and then development using a 1% aqueous KOH solution was performed for 30 seconds.
After that, the first electrode substrate after exposure and development is weighted and applied with a hanging load of 0.5 N. In this state, baking is performed at 150 ° C. for 60 minutes, and the suspension is suspended until it cools to room temperature. A partition wall portion was obtained on a one-electrode substrate. The height of the obtained partition wall part was 20 μm.

(Production of cell-type electrophoretic display device)
Next, a cell-type electrophoretic display device was manufactured by the following method using the first electrode substrate on which the partition walls were formed.

  A transfer film having an adhesive layer made of a thermoplastic resin on one surface was prepared, and the transfer film was placed on the partition wall so that the adhesive layer side was in contact with the top of the partition wall. In this state, while applying a predetermined pressing force, the periphery of the adhesive layer was heated to a temperature exceeding its softening temperature (about 100 ° C.), and the adhesive layer was thermally transferred onto the top of the partition wall. The thickness of the adhesive layer was 10 μm.

  Subsequently, a display medium (ink) having the following components is dropped from the dispenser on the surface side having the partition wall portion of the first electrode substrate, and a squeegee treatment is performed using a urethane squeegee located in the center, so that each cell Was filled with ink. The excess ink was scraped off using a urethane squeegee located at both ends, and further wiped off with a roll wiper.

<Display medium (ink) component>
・ Electrophoretic particles (titanium dioxide): 60 parts by weight-Dispersion liquid: 40 parts by weight

  Subsequently, a silver paste (manufactured by Fujikura Kasei Co., Ltd.) was spot-applied to a part of the outer periphery of the pattern with a dispenser to form a wiring for applying an electric field.

A second electrode substrate having a Cu electrode provided on one surface of a 100 μm thick polyethylene terephthalate (PET) film (manufactured by Teijin DuPont Co., Ltd.) is placed on the adhesive layer on the partition wall and subjected to atmospheric pressure ( Under a normal pressure atmosphere), a predetermined pressing force was applied and the periphery of the adhesive layer was heated to about 100 ° C.
Thereby, the 1st electrode substrate and the 2nd electrode substrate were pasted up via the adhesion layer.

After that, it is cut into a predetermined size, and a UV curable resin (LCB-610, manufactured by EACH Sea Co., Ltd.) is applied to the periphery of the first electrode substrate and the second electrode substrate using a dispenser. It was cured by exposure (exposure amount 700 mJ / cm ² ), and sealed to obtain a cell type electrophoretic display device.

[Comparative example]
(Preparation of partition wall)
A partition wall was formed on the first electrode substrate by the following method.

  The first electrode substrate after exposure and development in Examples was placed flat on a glass plate (manufactured by Nippon Electric Glass, non-alkali glass OA10, 370 mm × 470 mm × thickness 0.7 mm), and 150 ° C. with no load. After firing under conditions of 60 minutes, it was allowed to stand until it cooled to room temperature to form partition walls on the first electrode substrate. The height of the obtained partition wall part was 20 μm.

(Production of cell-type electrophoretic display device)
A cell-type electrophoretic display device was produced in the same manner as in the example using the first electrode substrate on which the partition walls were formed.

[Evaluation]
When the 1st electrode substrate in an Example was visually confirmed, deformation | transformation, such as a curl, a wave | undulation, and distortion, did not arise in the film substrate, but the 1st electrode substrate was maintaining planarity. In addition, in the cell type electrophoretic display device obtained according to the example, good display was obtained.
On the other hand, when the first electrode substrate in the comparative example was visually confirmed, the film substrate was wavy and the first electrode substrate was deformed. Further, in the cell-type electrophoretic display device obtained by the comparative example, the cell gap of the cells defined by the partition walls became non-uniform due to the undulation of the film substrate, and display unevenness occurred.

DESCRIPTION OF SYMBOLS 1 ... 1st electrode substrate 2 ... 2nd electrode substrate 3 ... Partition part 3 '... Partition part formation layer 4 ... Cell 5 ... Adhesion layer 6 ... Display medium 10 ... Cell-type electrophoretic display device 11 ... Film substrate 12 ... 1st Electrode layer 13 ... Support substrate 14 ... Second electrode layer

Claims (1)

A first electrode substrate having a film substrate and a first electrode layer formed on one surface of the film substrate, and a second electrode substrate having a support substrate and a second electrode layer formed on one surface of the support substrate Is arranged such that the first electrode layer and the second electrode layer face each other,
A partition wall between the first electrode substrate and the second electrode substrate;
A cell type electrophoretic display device in which a display medium including at least one kind of electrophores is enclosed in a plurality of cells defined by the partition walls between the first electrode substrate and the second electrode substrate. A manufacturing method comprising:
On the surface of the first electrode substrate having the first electrode layer, a baking step of forming a partition wall forming layer to be the partition wall by baking and baking at a temperature higher than the glass transition temperature of the film substrate;
Cooling the partition wall forming layer to form the partition wall,
At least the cooling step is performed in a state where the film substrate of the first electrode substrate is held on a flat surface, and a method for manufacturing a cell-type electrophoretic display device.