JP2012053184A - Display sheet and method for manufacturing display device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a display sheet in which an air layer does not remain between a housing portion (for particles) and a hard substrate even when the sheet is laminated with the hard substrate, and to provide a method for manufacturing a display device.SOLUTION: The display sheet 21 includes a hard substrate 100 and a display layer 400 including a plurality of housing portions 40 housing electrophoretic particles 5. The display layer 400 has a plurality of recesses 42 opening to one surface of the layer, and each recess 42 is opened directly or via another recess 42 to a side face of the display layer 400. The substrate 100 includes a color filter 7 that transmits light in a predetermined wavelength region.

Description

  The present invention relates to a display sheet and a method for manufacturing a display device.

For example, an electrophoretic display using particle electrophoresis is known as an image display unit of electronic paper (see, for example, Patent Document 1). The electrophoretic display has excellent portability and power saving, and is particularly suitable as an image display unit for electronic paper.
In Patent Document 1, a substrate on which a common electrode is formed (first substrate), a circuit substrate on which a plurality of pixel electrodes are formed (second substrate), and a plurality of microcapsules provided therebetween. There is disclosed a display device having a microcapsule-containing layer (display layer). In such a display device, a desired image is displayed by applying a voltage between each pixel electrode and the common electrode and moving the electrophoretic particles in the microcapsule to the pixel electrode side or the common electrode side. It is configured. In the display device of Patent Document 1, white particles that are positively charged and black particles that are negatively charged are used as the electrophoretic particles, so that black and white display is possible.
In such a display device, in order to enable full color display, for example, it is known to use a color filter (see, for example, Patent Document 2). Specifically, full-colorization is realized by adopting a configuration in which RGB color filters are formed on the substrate so as to correspond to the pixel electrodes.

  Moreover, as a manufacturing method of the display device described in Patent Document 1, a method is used in which a display sheet in which a microcapsule-containing layer is formed on a substrate and a circuit board are prepared, and these are bonded and bonded together. It is done. Here, in the manufacturing method as described above, when the display sheet and the circuit board are bonded together, an air layer may remain between the microcapsule and the circuit board. In such a case, a desired electric field cannot be applied to the microcapsules by the air layer, so that the image display characteristics of the display device are deteriorated.

In order to remove such an air layer (to prevent the generation of an air layer), it is known to use a roll laminating method when the display sheet and the circuit board are bonded together (for example, Patent Document 3). ). In this method, the circuit board is bonded to the display sheet in order from the end while being pressed with a roll, so that an air layer is effectively prevented from being generated. However, in order to use the roll laminating method, it is important that the display sheet or the circuit board has flexibility. If these are hard, the display sheet or the circuit board may be damaged during the roll laminating. There is.
Here, in the display device that enables full color display using the color filter as described above, the color filter is usually formed on a hard glass substrate. Therefore, in such a display device, there is a problem that it is not preferable to use the roll laminating method for the reason described above.

JP 2009-205003 A JP 2002-139750 A JP 2005-529361 A

  An object of the present invention is to provide a display sheet and a method for manufacturing a display device in which an air layer does not remain between a housing portion and a substrate even when bonded to a hard substrate.

Such an object is achieved by the present invention described below.
The display sheet of the present invention has a display layer including a plurality of storage portions in which at least one kind of particles is stored,
The display layer has a plurality of recesses opened on one surface of the display layer,
Each said recessed part is open | released to the side surface of the said display layer directly or through the other said recessed part.
Thereby, even if it bonds together with a hard board | substrate, the display sheet with which an air layer does not remain between an accommodating part and a board | substrate can be provided.

In the display sheet of the present invention, it has a flat hard substrate provided on the other surface side of the display layer,
It is preferable that the substrate has a Young's modulus of 10 GPa or more.
Thereby, the display layer can be reliably supported by the substrate. In addition, it can be accurately aligned (positioned) with the opposing substrate.

In the display sheet of the present invention, it is preferable that the substrate has a color filter that transmits light in a predetermined wavelength range.
Thereby, a display sheet capable of color display is obtained.
In the display sheet of this invention, it is preferable that the depth of the said recessed part is 5 micrometers or more.
Thus, if a hard plate-like member is attached to the display layer, the air between the housing portion and the substrate can be efficiently excluded from the side surface of the display layer through at least one recess. it can.

In the display sheet of the present invention, the storage portion has a spherical shape,
The plurality of recesses are preferably formed along outer walls of the plurality of storage portions.
Thereby, formation of a recessed part becomes easy and the depth of a recessed part can be controlled easily. Further, if a hard plate-like member is attached to the display layer, first, the plate-like member and the upper end portion of the housing portion can be brought into contact with each other. Therefore, it can prevent more reliably that an air layer intervenes between an accommodating part and the said plate-shaped member.

In the display sheet of this invention, it is preferable that at least one part of the said recessed part is formed of the outer wall of the said accommodating part.
Thereby, a recessed part can be formed more easily.
The display device manufacturing method of the present invention includes a first substrate and a plurality of containers that are provided on one surface side of the first substrate and in which an electrophoretic dispersion liquid including at least one kind of electrophoretic particles is enclosed. A display layer comprising a display portion, and a second substrate provided on the surface of the display layer opposite to the first substrate,
On one surface of the first substrate, there are a plurality of recesses that are open to the surface opposite to the first substrate, and each of the recesses opens to the side surface directly or via another recess. Forming the formed display layer;
By bonding the second substrate to the display layer and applying pressure to the display layer side, gas existing between the second substrate and the accommodating portion is crushed through the recess while the plurality of recesses are crushed. And a step of discharging from the side surface of the display layer to the outside.
As a result, a display device in which no air layer remains between the second substrate and the housing portion can be manufactured.

In the display device manufacturing method of the present invention, each of the first substrate and the second substrate is hard,
It is preferable that Young's modulus of each of the first substrate and the second substrate is 10 GPa or more.
Thereby, it is possible to more reliably prevent the air layer from remaining between the second substrate and the accommodating portion. Therefore, for example, highly accurate color display using a color filter formed on a general glass substrate can be realized.

In the method for manufacturing a display device of the present invention, it is preferable to pressurize the second substrate so that pressure is uniformly applied to the entire area of the second substrate.
Thereby, damage to the first substrate and the second substrate can be prevented.
In the method for manufacturing a display device of the present invention, it is preferable that the second substrate is bonded to the display surface while maintaining a state parallel to the first substrate.
Thereby, damage to the first substrate and the second substrate can be prevented. In addition, the second substrate can be accurately aligned with respect to the first substrate.
In the method for manufacturing a display device of the present invention, it is preferable that the second substrate and the display layer are bonded in the air.
Thereby, deterioration of the display layer can be prevented.

It is sectional drawing which shows typically 1st Embodiment of the display sheet of this invention. It is a top view of the color filter layer which the display sheet shown in FIG. 1 has. It is a top view of the display layer which the display sheet shown in FIG. 1 has. It is sectional drawing which shows the state which bonded the hard board | substrate to the display sheet shown in FIG. It is sectional drawing which shows the modification of the display layer which the display sheet shown in FIG. 1 has. It is sectional drawing which shows the modification of the display layer which the display sheet shown in FIG. 1 has. It is sectional drawing which shows typically the display apparatus to which the display sheet shown in FIG. 1 is applied. It is a schematic diagram for demonstrating the action | operation of the display apparatus shown in FIG. It is a schematic diagram for demonstrating the action | operation of the display apparatus shown in FIG. It is sectional drawing which shows typically the modification of the display apparatus shown in FIG. It is sectional drawing for demonstrating the manufacturing method of the display apparatus shown in FIG. It is sectional drawing for demonstrating the manufacturing method of the display apparatus shown in FIG. It is sectional drawing for demonstrating the manufacturing method of the display apparatus shown in FIG. It is sectional drawing for demonstrating the manufacturing method of the display apparatus shown in FIG. It is sectional drawing for demonstrating the manufacturing method of the display apparatus shown in FIG. It is sectional drawing which shows the modification of the display sheet shown in FIG. It is sectional drawing which shows typically the display sheet concerning 2nd Embodiment of this invention. It is sectional drawing which shows typically the display sheet concerning 3rd Embodiment of this invention. It is sectional drawing which shows typically the display sheet concerning 4th Embodiment of this invention.

Hereinafter, the display sheet and display device manufacturing method of the present invention will be described in detail based on preferred embodiments shown in the accompanying drawings.
<First Embodiment>
1 is a cross-sectional view schematically showing a first embodiment of a display sheet of the present invention, FIG. 2 is a plan view of a color filter layer included in the display sheet shown in FIG. 1, and FIG. 3 is a display shown in FIG. 4 is a plan view of a display layer included in the sheet, FIG. 4 is a cross-sectional view illustrating a state in which a hard substrate is bonded to the display sheet illustrated in FIG. 1, and FIGS. 5 and 6 each include the display sheet illustrated in FIG. FIG. 7 is a cross-sectional view schematically showing a display device to which the display sheet shown in FIG. 1 is applied, and FIGS. 8 and 9 explain the operation of the display device shown in FIG. FIG. 10 is a cross-sectional view schematically showing a modification of the display device shown in FIG. 7, and FIGS. 11 to 15 are cross-sectional views for explaining a method of manufacturing the display device shown in FIG. 16 is a cross-sectional view showing a modification of the display sheet shown in FIG. In the following description, for convenience of explanation, the upper side in FIGS. 1 and 4 to 15 will be described as “upper” and the lower side as “lower”.

1. Display Sheet First, the display sheet of the present invention will be described.
As shown in FIG. 1, the display sheet 21 includes a hard substrate (first substrate) 100 and a display layer 400 provided on the substrate 100. In the display sheet 21 of the present embodiment, since the substrate 100 is hard, the display layer 400 can be reliably supported by the substrate 100 and can be accurately aligned with a circuit substrate 22 and the like described later.
Hereinafter, the substrate 100 and the display layer 400 will be sequentially described in detail.

1-1. Substrate (color filter substrate)
As shown in FIG. 1, a substrate 100 includes a sheet-like (flat plate-like) base 71, a grid-like black matrix 72 formed on the base 71, and a color material film formed in each gap of the black matrix 72. 73, a color filter 7 composed of a protective layer 74 formed so as to cover the black matrix 72 and the color material film 73, and a common electrode (second electrode) 4 formed on the protective layer 74. Have.

As the base 71, for example, a hard substrate such as a glass substrate is used. This facilitates the formation of the black matrix 72 and the color material film 73. The base 71 is substantially colorless and transparent. In addition, it is preferable to use a base having a Young's modulus of 10 GPa or more.
As shown in FIG. 2, a black matrix 72 is formed on one surface of the base 71. The black matrix 72 is formed in a lattice shape, and a plurality of spaces (openings) 721 having a substantially rectangular shape are formed in a matrix shape by being surrounded by the black matrix 72. For example, the black matrix 72 has a function of preventing light from leaking from a gap between adjacent color material films 73 and preventing color mixture of adjacent color material films 73, thereby improving contrast. Can be planned.

A color material film 73 is formed in each space 721. The color material film 73 has a function of transmitting light in a specific wavelength range. In the present embodiment, the color material film 73 includes a red color material film 73R, a green color material film 73G, and a blue color material film 73B. The color material films 73R, 73G, and 73B are arranged side by side, and these three color material films 73R, 73G, and 73B constitute one pixel Pix. Thereby, the full color display of the display sheet 21 is implement | achieved.
In the illustrated configuration, the arrangement of the color material films 73 is a so-called mosaic arrangement, but the arrangement of the color material films 73 is not limited to this, and may be, for example, a delta arrangement. Moreover, the formation method of the color material film 73 is not specifically limited, Well-known techniques, such as a pigment dispersion method, the dyeing method, the electrodeposition method, the printing method, the inkjet method, can be used.

The protective layer 74 has a function of protecting the black matrix 72 and the color material film 73 and a function of filling a step between the black matrix 72 and the color material film 73. Such a protective layer 74 is substantially colorless and transparent, and is made of a resin material such as PET (polyethylene terephthalate) or PEN (polyethylene naphthalate).
A common electrode 4 having a film shape is provided on the upper surface of the protective layer 74 (that is, the surface on the display layer 400 side). The common electrode 4 is light transmissive, that is, substantially colorless and transparent.

The constituent material of the common electrode 4 is not particularly limited as long as it is substantially conductive. For example, an electroconductive polymer material such as polyacetylene, polyfluorene, or a derivative thereof, or a matrix such as polyvinyl alcohol or polycarbonate. An ion conductive polymer material in which an ionic substance such as NaCl, Cu (CF ₃ SO ₃ ) ₂ is dispersed in a resin, indium oxide (IO), indium tin oxide (ITO), fluorine-doped tin oxide ( Various conductive materials such as conductive oxide materials such as FTO) can be used, and one or more of these can be used in combination.
The average thickness of the common electrode 4 is appropriately set depending on the constituent material, application, etc., and is not particularly limited, but is preferably about 0.01 μm or more and 1 μm or less, and is preferably about 0.02 μm or more and 0.5 μm or less. Is more preferable.

1-2. Display Layer The display layer 400 is provided in contact with the upper surface of the common electrode 4. The display layer 400 has a configuration in which a plurality of microcapsules (accommodating portions) 40 in which the electrophoretic dispersion liquid 10 is enclosed in a capsule body 401 are held by a binder 41.
As shown in FIG. 1, the microcapsules 40 are formed in a single layer on the substrate 100 so as to be parallel in the vertical and horizontal directions (that is, one by one without overlapping in the thickness direction), and in the thickness direction of the display layer 400 It is arranged throughout. That is, in the display layer 400, the microcapsules 40 adjacent to each other in the surface direction are in contact with each other and are arranged without being stacked in the thickness direction. The microcapsules 40 are substantially spherical (spherical) without being compressed in the vertical direction.

  The capsule strength of the microcapsule 40 is preferably 0.6 MPa or more, more preferably 1.0 MPa or more, and further preferably 3.0 MPa or more. The upper limit of the capsule strength is not particularly limited, but is about 50 MPa, for example. In addition, the capsule strength of the microcapsule 40 means the compressive strength per microcapsule measured using a micro compression tester (for example, product name: MCT-W500, manufactured by Shimadzu Corporation).

  Further, the microcapsule 40 has a capsule strength that is not crushed even when the steel ball is dropped from a height of preferably 10 cm or more, more preferably 20 cm or more, and even more preferably 30 cm or more in the steel ball drop test. preferable. In general, when the microcapsule 40 has only a capsule strength that is crushed when the steel ball is dropped from a height lower than the above height in the steel ball drop test, the display device 20 using such a microcapsule 40 is used. If it is accidentally dropped, the microcapsule 40 may be crushed by the impact of the drop, and there is a possibility that data display at that portion (pixel) cannot be performed. In the steel ball drop test, after placing the display device 20 on a butadiene rubber having a thickness of 3 mm, a steel ball having a diameter of 11 mm and a mass of 5.468 g is placed on the display layer 400 of the display device 20 from an arbitrary height. It is performed by observing with a light microscope the microcapsules 40 that are vertically dropped and are present at the location where the steel ball hits.

In addition, the microcapsule 40 has a certain degree of flexibility, and its shape changes depending on the external pressure. Therefore, the microcapsule 40 is not particularly limited. It is preferable that it is a shape.
The degree of the spherical shape of the microcapsule 40 can be expressed by using the ratio of the width of the microcapsule 40 and the height of the microcapsule 40 (the width of the microcapsule 40 / the height of the microcapsule 40) as an index. The width of the microcapsules 40 / the height (average value) of the microcapsules 40 is, for example, the average value of the particle diameter in the display layer 400 with respect to the height (thickness direction) and width (plane direction) of each microcapsule 40. Each is obtained and the ratio (width / height) of these average values is obtained.

  The width of the microcapsules 40 thus obtained / the height (average value) of the microcapsules 40 is not particularly limited, but is preferably about 1.0 or more and 1.2 or less, preferably 1.0 or more. More preferably, it is about 1.15 or less. When the width of the microcapsules 40 / the height of the microcapsules 40 are within the above range, it can be said that the microcapsules 40 are present in a state of maintaining a substantially spherical shape. In this way, the microcapsules 40 that maintain a substantially spherical shape are arranged in the display layer 400 such that those adjacent in the surface direction are in contact with each other and are not stacked in the thickness direction. As a result, the display sheet 21 including the display layer 400 exhibits high contrast.

  The particle size of the microcapsule 40 is not particularly limited, but is preferably about 5 μm or more and 300 μm or less, more preferably about 10 μm or more and 200 μm or less, and about 15 μm or more and 150 μm or less. Further preferred. If the particle size of the microcapsule 40 is less than 5 μm, depending on the hue, particle size and amount (number) of the electrophoretic particles 5 accommodated in the microcapsule 40, a sufficient display density may not be obtained. There is. On the contrary, when the particle size of the microcapsule exceeds 300 μm, the capsule strength of the microcapsule 40 may be reduced depending on the configuration of the microcapsule 40 (constituent materials, etc.). The electrophoretic properties of the electrophoretic particles 5 in the electrophoretic dispersion 10 are not sufficiently exhibited, and the driving voltage for display may be increased. The particle size of the microcapsule 40 is measured with a laser diffraction / scattering particle size distribution measuring device (for example, product name: LA-910, manufactured by Horiba, Ltd., Cole Counter Multisizer 3, Beckman Coulter, Inc.). Mean volume average particle size.

  Further, the variation coefficient of the particle size of the microcapsule 40 (that is, the narrowness of the particle size distribution) is not particularly limited, but is preferably 30% or less, more preferably 20% or less, and 10% or less. More preferably. When the variation coefficient of the particle size of the microcapsule 40 exceeds 30%, there are few microcapsules 40 having an effective particle size, and it may be necessary to use a large number of microcapsules. Further, even when the same voltage is applied between the first electrode 3 and the second electrode 4, the magnitude of the applied electric field differs between the plurality of microcapsules 40, and the display characteristics are deteriorated. There is a fear.

Note that the particle size of the microcapsules 40 and the coefficient of variation thereof greatly depend on the particle size and particle size distribution of the dispersion liquid dispersed in the aqueous medium when the microcapsules 40 are manufactured. Therefore, the microcapsule 40 having a desired particle diameter and its coefficient of variation can be obtained by appropriately adjusting the dispersion conditions of the dispersion.
The constituent material of the capsule body 401 is not particularly limited. For example, gelatin, a composite material of gum arabic and gelatin, urethane resin, melamine resin, urea resin, epoxy resin, phenol resin, acrylic resin Various resin materials such as resins, urethane resins, olefin resins, polyamides, and polyethers can be used, and one or more of these can be used in combination.

The electrophoretic dispersion liquid 10 enclosed in the capsule body 401 is obtained by dispersing (suspending) the electrophoretic particles 5 in the liquid phase dispersion medium 6. The electrophoretic particles 5 include a plurality of white particles (first particles) 5a that are positively or negatively charged, and colored particles that are charged to a polarity opposite to that of the white particles 5a and have a light reflectance lower than that of the white particles ( Second particles) 5b.
For example, the electrophoretic particles 5 are dispersed in the liquid phase dispersion medium 6 by combining one or more of paint shaker method, ball mill method, media mill method, ultrasonic dispersion method, stirring dispersion method, and the like. be able to.

  As the liquid phase dispersion medium 6, a medium having a low solubility in the capsule body 401 and a relatively high insulating property is preferably used. Examples of the liquid phase dispersion medium 6 include various types of water (for example, distilled water and pure water), alcohols such as methanol, cellosolves such as methyl cellosolve, esters such as methyl acetate, ketones such as acetone, Aliphatic hydrocarbons such as pentane (liquid paraffin), alicyclic hydrocarbons such as cyclohexane, aromatic hydrocarbons such as benzene, halogenated hydrocarbons such as methylene chloride, and aromatic heterocycles such as pyridine , Nitriles such as acetonitrile, amides such as N, N-dimethylformamide, carboxylate, silicone oil or other various oils, and the like can be used alone or as a mixture.

  Among them, the liquid phase dispersion medium 6 is preferably a material mainly composed of aliphatic hydrocarbons (liquid paraffin) or silicone oil. The liquid phase dispersion medium 6 containing liquid paraffin or silicone oil as a main component has a high aggregation suppressing effect on the electrophoretic particles 5 and has low affinity with the constituent material of the capsule body 401 (low solubility). preferable. Thereby, it can prevent or suppress more reliably that the display performance of the display apparatus 20 deteriorates with time. In addition, liquid paraffin or silicone oil is preferable from the viewpoint of excellent weather resistance and high safety because it does not have an unsaturated bond.

  Further, in the liquid phase dispersion medium 6, for example, a surfactant (anionic or cationic) such as an electrolyte or an alkenyl succinate, a metal soap, a resin material, a rubber material, an oil, a varnish, and the like, as necessary. Various additives such as a charge control agent composed of particles such as a compound, a dispersant such as a silane coupling agent, a lubricant, and a stabilizer may be added. When the liquid phase dispersion medium 6 is colored, various dyes such as anthraquinone dyes, azo dyes, and indigoid dyes may be dissolved in the liquid phase dispersion medium 6 as necessary.

  The electrophoretic particles 5 are particles that have a charge and can be electrophoresed in the liquid phase dispersion medium 6 when an electric field is applied. Any electrophoretic particle 5 may be used as long as it has a charge. Although there is no particular limitation, at least one of pigment particles, resin particles, or composite particles thereof is preferably used. used. These particles have the advantage that they are easy to manufacture and the charge can be controlled relatively easily.

  Examples of the pigment constituting the pigment particles include black pigments such as aniline black, carbon black, titanium black and copper chromite, white pigments such as titanium oxide and antimony oxide, azo pigments such as monoazo, isoindolinone, Yellow pigments such as yellow lead, red pigments such as quinacridone red and chrome vermilion, blue pigments such as phthalocyanine blue and indanthrene blue, green pigments such as phthalocyanine green, etc. They can be used in combination.

Examples of the resin material constituting the resin particles include acrylic resin, urethane resin, urea resin, epoxy resin, polystyrene, polyester, and the like, and one or more of these are combined. Can be used.
The composite particles include, for example, those in which the surface of the pigment particles is coated with a resin material or other pigment, those in which the surface of the resin particles is coated with a pigment, or a mixture in which the pigment and the resin material are mixed at an appropriate composition ratio. The particle | grains comprised by these, etc. are mentioned.

Examples of particles obtained by coating the surface of pigment particles with other pigments include those obtained by coating the surface of titanium oxide particles with silicon oxide or aluminum oxide. Such particles are suitable as white particles 5a. Used. Further, the carbon black particles or particles covering the surface thereof are suitably used as the colored particles (black particles) 5b.
Further, the shape of the electrophoretic particles 5 is not particularly limited, but is preferably spherical.

  The average particle diameter of the electrophoretic particles 5 is not particularly limited, but is preferably 0.1 to 5 μm, more preferably 0.1 to 4 μm, and still more preferably 0.1 to 3 μm. If the average particle size of the electrophoretic particles 5 is less than 0.1 μm, sufficient chromaticity cannot be obtained, and when used in an electrophoretic display device, the contrast may be lowered and the display may become unclear. . Conversely, when the average particle diameter of the electrophoretic particles 5 exceeds 5 μm, it is necessary to increase the coloring degree of the particles more than necessary, which increases the amount of pigments used and is used for electrophoretic display devices. In some cases, it is difficult to quickly move the electrophoretic particles at a portion where a voltage is applied for display, and the response speed (display response) may decrease.

In addition, the average particle diameter of the electrophoretic particles 5 means a volume average particle diameter measured with a dynamic light scattering particle size distribution measuring apparatus (for example, product name: LB-500, manufactured by Horiba, Ltd.).
The specific gravity of the electrophoretic particles 5 is preferably set to be approximately equal to the specific gravity of the liquid phase dispersion medium 6. Thereby, even after the application of voltage between the electrodes 3 and 4 is stopped, the electrophoretic particles 5 can stay in a certain position in the liquid phase dispersion medium 6 for a long time. That is, the display sheet 21 can be provided with a memory property, and the displayed information is held for a long time.

  The binder 41 included in the display layer 400 is supplied for the purpose of fixing the display layer 400 to the substrate 100, the purpose of fixing the microcapsules 40 to each other, and the like. Thereby, the durability and reliability of the display sheet 21 can be further improved. As will be described later, when the display device 20 is manufactured using the display sheet 21, the binder 41 is further provided between the pixel electrode (first electrode) 3 and the common electrode 4 included in the display device 20. For the purpose of securing the insulation of the circuit board 22 to the display sheet 21.

For the binder 41, a resin material (resin material having only an insulating property or a flow of only a small current) having excellent affinity (adhesiveness) with the substrate 100 and the capsule body 401 and having excellent insulating properties is preferably used.
Examples of the binder 41 include (meth) acrylic resins, (meth) acrylic urethane resins, polyvinyl chloride resins, polyvinylidene chloride resins, melamine resins, urethane resins, styrene resins, and alkyds. Resin, phenol resin, epoxy resin, polyester resin, polyvinyl alcohol resin, (meth) acrylic silicone resin, alkylpolysiloxane resin, silicone resin, silicone alkyd resin, silicone urethane resin, silicone polyester Resin, synthetic resin binder such as polyalkylene glycol resin, ethylene-propylene copolymer rubber, polybutadiene rubber, styrene-butanediene rubber, synthetic rubber such as acrylonitrile-butadiene rubber, or natural rubber binder Examples thereof include thermoplastic or thermosetting polymer binders such as cellulose nitrate, cellulose acetate butyrate, cellulose acetate, ethyl cellulose, hydroxypropylmethyl cellulose, and hydroxyethyl cellulose, and one or more of these are used in combination. be able to.

Among these binders 41, (meth) acrylic resins, polyester resins, urethane resins are preferable in that the dispersibility of the microcapsules 40 is relatively good and the adhesiveness between the substrate 100 and the capsule body 401 is excellent. Polyalkylene glycol resins are preferably used, and (meth) acrylic resins are particularly preferably used.
Heretofore, each part of the display layer 400 has been described.

  As shown in FIGS. 1 and 3, the display layer 400 has a plurality of recesses 42 opened on the upper surface thereof. Each recess 42 is open (communication) to the side surface 400 a of the display layer 400 directly or via another recess 42. Specifically, the recess 42a located at the edge of the display layer 400 is directly open to the side surface of the display layer 400, and the recess 42b located at the center of the display layer 400 includes the recess 42b and the display layer 400. The display layer 400 is open to the side surface via at least one recess 42 located between the side surface and the side surface of the display layer 400.

In other words, as shown in FIG. 1, when a plane that intersects with the apex of the thickest portion of the display layer 400 and is parallel to the substrate 100 is set as the reference plane F, the adjacent recesses 42 are separated from each other by the reference plane F. It communicates on the lower side.
By forming such a recess 42 in the display layer 400, it is ensured that an air layer (bubble) remains between the substrate and the display layer 400 when the substrate is attached to the upper surface of the display layer 400. Can be prevented.

  Specifically, as shown in FIG. 4A, a hard substrate 500 such as a glass substrate is placed on the upper surface of the display layer 400, and the substrate 500 is uniform in the thickness direction and in the entire region. By applying pressure so that pressure is applied to the display sheet 21 (pressing the display sheet 21), the concave portions 42 are gradually crushed together with the microcapsules 40, and at the same time, the air between the substrate 500 and the display layer 400 is at least one. It is discharged from the side surface 400 a of the display layer 400 through the recess 42. That is, at this time, the recess 42 functions as an air escape path.

Then, as shown in FIG. 4B, the recess 42 is finally crushed and an assembly having no air layer between the display layer 400 and the substrate 100 (for example, the display device 20 described later) is obtained. .
Here, the depth (average depth) of the recess 42 is preferably 5 μm or more. Thereby, the air between the microcapsule 40 and the substrate 500 can be efficiently excluded from the side surface 400 a of the display layer 400 through the at least one recess 42. The upper limit value of the depth of the recess 42 is not particularly limited, but is preferably about 20 μm. Thereby, the depth of the recess 42 becomes appropriate, and the recess 42 can be completely crushed.

Further, the surface roughness (center line surface roughness) Ra of the surface of the display layer 400 having such recesses 42 is preferably 3 μm or more. Thereby, the effect similar to the above can be exhibited.
Further, the recess 42 is formed along the outer wall of the microcapsule 40. Thereby, formation of the recess 42 is facilitated, and the depth of the recess 42 can be easily controlled. In addition, when the substrate 500 is attached to the display layer 400, first, the substrate 500 and the upper end portion of the microcapsule 40 can be brought into contact with each other. Therefore, it is possible to prevent the air layer between the microcapsule 40 and the substrate 500 more reliably.

  In this embodiment, the binder 41 is supplied so as to be approximately half the height of the display layer 400, and the upper part (upper half) of each microcapsule 40 is exposed from the binder 41 (binder layer 41 ′). ing. That is, each microcapsule 40 is held by the binder layer 41 ′, and the upper portion thereof is exposed from the binder layer 41 ′. Then, at least a part of the recess 42 is formed by the outer wall of the exposed portion of the microcapsule 40. By setting it as such a structure, the recessed part 42 can be formed more easily.

  The thickness of the binder layer 41 ′ is not particularly limited, but is preferably higher than half the particle size (average particle size) of the microcapsules 40. In other words, the thickness of the binder layer 41 ′ is preferably half or more of the thickness of the display layer 400. That is, for example, as shown in FIG. 5, the thickness of the binder layer 41 ′ is preferably about ¾ of the thickness of the display layer 400. Thereby, while the depth of the recessed part 42 becomes an appropriate depth, the quantity of the binder 41 in the display layer 400 can be made into an appropriate quantity. Therefore, when the substrate 500 is bonded to the display layer 400 and pressed, the air between the substrate 500 and the display layer 400 can be more reliably removed, and the concave portion 42 is crushed after bonding. (Can be extinguished).

Further, in the present embodiment, the portion exposed from the binder layer 41 ′ of the microcapsule 40 is exposed to the outside of the display layer 400, but is not limited thereto. For example, as shown in FIG. A film-like binder 41 may be attached to the substrate. Also in this case, the same effect as this embodiment can be exhibited.
The display sheet 21 has been described above.

2. Display Device Next, a display device (electrophoretic display device) 20 to which the display sheet 21 is applied will be described.
As illustrated in FIG. 7, the display device 20 includes a display sheet 21, a circuit board 22, and a sealing unit 9. In such a display device 20, the surface of the base 71 of the display sheet 21 constitutes the display surface 201. Hereinafter, although each part is demonstrated sequentially, since the structure of the display sheet 21 is as above-mentioned, the description is abbreviate | omitted.

2-1. Circuit Board The circuit board 22 is provided so as to face the substrate 100 with the display layer 400 interposed therebetween. Such a circuit board 22 includes a hard base 11, a circuit (not shown) including a switching element such as a TFT provided on the base 11, and a plurality of pixel electrodes (first electrodes) 3. Yes.

The base 11 is hard. For the hardness of the base 11, for example, a material having a Young's modulus of 10 GPa or more is used. Although it does not specifically limit as a constituent material of the base 11, For example, glass, quartz, various stainless steel, silicon (Si) etc. can be used.
The average thickness of the base 11 is appropriately set depending on the constituent material, application, etc., and is not particularly limited, but is preferably about 100 μm or more and 500 μm or less, and more preferably about 100 μm or more and 250 μm or less. Thereby, the display device 20 can be thinned while ensuring the strength of the display device 20.

  A layered pixel electrode 3 is provided on the surface of the base 11 on the display layer 400 side. The pixel electrode 3 has a plurality of electrodes (electrodes connected to switching elements) divided in a matrix. The pixel electrode 3 is provided so that the plurality of electrodes face the plurality of color material films 73 included in the color filter 7, that is, one electrode faces the one color material film 73. In such a display device 20, when a voltage is applied between the pixel electrode 3 and the common electrode 4, an electric field is generated between them, and this electric field acts on the electrophoretic particles 5 in the microcapsule 40.

In the present embodiment, one microcapsule 40 is positioned on one individual electrode. However, the present invention is not limited to this. For example, a plurality of (for example, about ten) on one individual electrode. The structure in which the microcapsules 40 are located may be used.
The constituent material of the pixel electrode 3 is not particularly limited as long as it is substantially conductive. For example, the same material as that of the common electrode 4 described above can be used.
The average thickness of the pixel electrode 3 is appropriately set depending on the constituent material, application, etc., and is not particularly limited, but is preferably about 0.01 μm or more and 1 μm or less, preferably about 0.02 μm or more and 0.5 μm or less. It is more preferable that

2-2. Sealing portion The sealing portion 9 is provided between the substrate 100 and the circuit board 22 and along the edges thereof. The display layer 400 is hermetically sealed by the sealing portion 9. Thereby, it is possible to prevent moisture from entering the display device 20 and more reliably prevent display performance deterioration of the display device 20.

Examples of the constituent material of the sealing portion 9 include thermoplastic resins such as acrylic resins, urethane resins, and olefin resins, epoxy resins, melamine resins, thermosetting resins such as phenol resins, and the like. Various resin materials etc. are mentioned, Among these, it can use combining 1 type (s) or 2 or more types. In addition, the sealing part 9 should just be provided as needed, and can also be abbreviate | omitted.
The configuration of the display device 20 has been described above.

3. Operation of Display Device 20 The display device 20 operates as follows.
When a voltage is applied between the pixel electrode 3 and the common electrode 4 of the display device 20, an electric field is generated between them. In accordance with this electric field, the electrophoretic particles 5 (colored particles 5 b and white particles 5 a) migrate in the liquid phase dispersion medium 6 toward either the pixel electrode 3 or the common electrode 4.

  For example, when a white particle 5a having a positive charge is used and a negative charge is used as the colored particle (black particle) 5b, as shown in FIG. 8A, when the pixel electrode 3 is set to a positive potential, The white particles 5 a move to the common electrode 4 side and gather at the common electrode 4. On the other hand, the colored particles 5b move to the pixel electrode 3 side and gather at the pixel electrode 3 (hereinafter, this state is referred to as “first state”). In the first state, the light transmitted through the color material film 73 is reflected by the white particles 5a in the microcapsules 40 and is transmitted again through the color material film 73, whereby the color of the color material film 73 is displayed. .

On the contrary, as shown in FIG. 8B, when the pixel electrode 3 is set to a negative potential, the white particles 5 a move to the pixel electrode 3 side and gather at the pixel electrode 3. On the other hand, the colored particles 5b move to the common electrode 4 side and gather at the common electrode 4 (hereinafter, this state is referred to as “second state”). In the second state, since the light transmitted through the color material film 73 is absorbed by the colored particles 5b in the microcapsules 40, black is displayed.
By selecting the first state or the second state for each pixel electrode 3, a desired image can be displayed on the display surface 201.

For example, one pixel Pix will be described. As shown in FIG. 9A, a microcapsule 40R corresponding to the color material film 73R, a microcapsule 40G corresponding to the color material film 73G, and a microcapsule corresponding to the color material film 73B. When each of the capsules 40B is in the first state, white is displayed by additive color mixture. Conversely, as shown in FIG. 9B, when the microcapsules 40R, 40G, and 40B are in the second state, black is displayed. Further, as shown in FIG. 8C, when the microcapsule 40R is set to the first state and the microcapsules 40G and 40B are set to the second state, red is displayed.
As described above, the display device 20 of the present embodiment has a configuration in which the concave portion 42 of the display layer 400 is completely eliminated, but a desired voltage is applied between the common electrode 4 and the pixel electrode 3. In this case, as long as a desired electric field can be applied to the microcapsules 40, the recesses 42 do not have to disappear completely as shown in FIG.

4). Display device manufacturing method (display device manufacturing method of the present invention)
Next, a method for manufacturing the display device 20 will be described in detail with reference to FIGS.
The manufacturing method of the display device 20 includes a process A for preparing (manufacturing) the display sheet 21, a process B for attaching the circuit board 22 to the display sheet 21 prepared in the process A, and a process C for forming the sealing portion 9. have. Hereinafter, steps A and B will be described in sequence.

4-1. Process A
The process A includes a process A1 for manufacturing the substrate 100 and a process A2 for forming the display layer 400 on the substrate 100 obtained in the process A1.
[Step A1]
First, as shown in FIG. 11A, a colorless and transparent glass substrate 200 is prepared and a base 71 is obtained. Next, as shown in FIG. 11B, a metal layer 210 made of chromium (Cr) is formed on the base 71 by, for example, a sputtering method. Next, as illustrated in FIG. 11C, a resist film M <b> 1 is formed on the metal layer 210, and the resist film M <b> 1 is patterned into a shape corresponding to the black matrix 72. Next, after the metal layer 210 is etched through the resist film M1, the resist film M1 is removed. As a result, a black matrix 72 is formed on the base 71 as shown in FIG.

  Next, a liquid (for example, a colored polyimide precursor liquid in which a red pigment is dispersed) that is a raw material of the color material film 73R is applied onto the base 71 by a spin coat method, and then dried, whereby FIG. A colored resin layer 220 as shown in FIG. Next, as shown in FIG. 11F, a resist film M1 is formed on the colored resin layer 220, and this resist film M2 is patterned into a shape corresponding to the color material film 73R. Next, after the colored resin layer 220 is etched through the resist film M2, the resist film M2 is removed. As a result, a color material film 73R is formed on the base 71 as shown in FIG. Similarly, color material films 73G and 73B are formed on the base 71, respectively. Next, as shown in FIG. 12B, a transparent and transparent resin material is applied so as to cover the black matrix 72 and the color material film 73, and dried to obtain the protective layer 74. Next, as shown in FIG. 12C, a thin film made of, for example, ITO is formed on the surface of the protective layer 74 to form the common electrode 4. Through the above steps, the substrate 100 is obtained.

[Step A2]
First, the microcapsule 40 manufactured by a known method and the binder 41 are mixed with a solvent (for example, alcohol such as ethanol) to obtain a microcapsule coating solution 300. Here, the mixing ratio of the microcapsule 40 and the binder 41 is adjusted so that the weight of the binder 41 is reduced, for example, the weight ratio of the microcapsule 40 and the binder 41 is about 2: 1 to 3: 1. It is preferable to do this. Next, as shown in FIG. 13A, the microcapsule coating liquid 300 is applied onto the common electrode 4 of the substrate 100 obtained in step A3 using, for example, a die coater. If necessary, the surface of the microcapsule coating liquid 300 applied on the common electrode 4 may be leveled with a squeegee or the like. After coating, the binder 41 is sufficiently moved downward by its own weight by being left for a predetermined time. After the binder 41 has been moved downward, the solvent is volatilized to obtain the display layer 400 in which a plurality of recesses 42 are formed as shown in FIG. Thus, the display sheet 21 is obtained.
In addition, after the display sheet 21 is obtained and before the display sheet 21 and the circuit board 22 are bonded together, adhesion of dust to the surface of the display layer 400 and contact with the outside air are prevented, and adhesion (adhesion) In order to maintain the property, a release sheet may be attached to the display layer 400 as shown in FIG.

[Step B]
For example, a circuit substrate 22 obtained by forming TFTs and pixel electrodes 3 on a hard base 11 such as a glass substrate or a ceramic substrate is prepared. Next, the circuit board 22 is bonded to the display sheet 21 obtained in the process A. This step is performed in air (atmosphere). Thereby, since the water | moisture content in the display layer 400 can be prevented from volatilizing, the display apparatus 20 excellent in the display characteristic and durability can be manufactured. A technique for preventing an air layer from interposing between the circuit board 22 and the display sheet 21 by bonding the circuit board 22 to the display sheet 21 in a vacuum is also known, but this method is used. Then, by being placed in a vacuum environment, moisture in the display layer 400 (particularly moisture contained in the binder 41) volatilizes, leading to deterioration of the display layer 400.

  Specifically, as shown in FIG. 14A, the circuit substrate 22 is displayed on the surface of the display layer 400 of the display sheet 21 obtained in step A (the surface opposite to the color filter 7) on the pixel electrode 3 side. It is placed so as to face the layer 400 and align with the display sheet 21. In this state, the circuit board 22 is only in contact with the upper part of the microcapsule 40 and the recess 42 is not crushed.

  Next, as shown in FIG. 14B, the circuit board 22 is pressed so as to be pressed against the display sheet 21. At this time, the circuit board 22 is pressurized so that the pressure is uniformly applied to the entire area of the circuit board 22. That is, the circuit board is pressed against the display sheet 21 while keeping the circuit board 22 and the display sheet 21 (substrate 100) in parallel. Thereby, damage to the hard circuit board 22 and the board 100 can be prevented. By pressing the circuit board 22 against the display sheet 21, the microcapsule 40 is deformed into a flat shape and the concave portion 42 is gradually crushed. The air existing between the circuit board 22 and the display layer 400 is discharged from the side surface of the display layer 400 through the recess 42 (as a loop) as the recess 42 is crushed. Further, when the microcapsule 40 is deformed into a flat shape, a part of the binder 41 enters the recess 42. As a result, the concave portion 42 is eliminated. Thereafter, the pressing is finished.

[Step C]
As shown in FIG. 15A, the sealing portion 9 is formed between the circuit board 22 and the substrate 100 so as to surround the display layer 400. Thereby, the display device 20 in which no air layer is interposed between the display layer 400 (microcapsule 40) and the circuit board 22 is obtained.
According to such a display device 20, when a voltage having a desired strength is applied between the common electrode 4 and the pixel electrode 3, an electric field having a desired strength corresponding to the voltage value is applied to the microcapsule 40. Therefore, the electrophoretic particles 5 in the microcapsule 40 can be surely brought into the first state or the second state. Therefore, the display device 20 can exhibit excellent display characteristics.

If an air layer is interposed between the microcapsule 40 and the circuit board 22 (pixel electrode 3), the distance between the common electrode 4 and the pixel electrode 3 is increased by the thickness of the air layer. Since the air layer functions as an insulating layer, even if a voltage having a predetermined strength is applied between the pixel electrode 3 and the common electrode 4, an electric field having a sufficient strength does not act on the microcapsules 40, and as a result. The movement of the electrophoretic particles 5 becomes insufficient, and the display characteristics of the display device 20 are deteriorated.
The first embodiment has been described above. In the present embodiment, the substrate 100 has a configuration in which the common electrode 4 is directly formed on the protective layer 74, but is not limited thereto. For example, as shown in FIG. You may use the structure which joined the base material 12 which forms the common electrode 4 on one surface of the base 2 to the color filter 7. FIG.

Second Embodiment
Next, a second embodiment of the display sheet of the present invention will be described.
FIG. 17 is a cross-sectional view schematically showing a display sheet according to the second embodiment of the present invention.
Hereinafter, although the display sheet concerning 2nd Embodiment is demonstrated, it demonstrates centering around difference with 1st Embodiment mentioned above, The description is abbreviate | omitted about the same matter.

The display sheet according to the present embodiment has the same configuration as that of the first embodiment described above except that the configuration of the display layer is different.
As shown in FIG. 17, the display layer 400 </ b> A included in the display sheet 21 </ b> A of this embodiment has a larger amount of binder 41 than the display layer 400 of the first embodiment, and the entire region of the microcapsule 40 is surrounded by the binder 41. It is. That is, unlike the first embodiment, the microcapsules 40 are not exposed from the binder 41 (binder layer 41 ′). Even in such a display layer 400A, the upper surface of the display layer 400A is wavy along the outer wall of the microcapsule 40, whereby a plurality of recesses 42 are formed.

In the present embodiment, the concave portion 42 is formed by relatively increasing the viscosity of the binder 41. The viscosity of the binder 41 is preferably 10 Pa · s or more, for example. If the viscosity is lower than this, the binder 41 may flow, and the upper surface of the display layer 400 may become flat.
Also according to the second embodiment, the same effects as those of the first embodiment described above can be exhibited.

<Third Embodiment>
Next, a third embodiment of the display sheet of the present invention will be described.
FIG. 18 is a cross-sectional view schematically showing a display sheet according to the third embodiment of the present invention.
Hereinafter, although the display sheet concerning 3rd Embodiment is demonstrated, it demonstrates centering around difference with 1st Embodiment mentioned above, The description is abbreviate | omitted about the same matter.

The display sheet according to the present embodiment has the same configuration as that of the first embodiment described above except that the configuration of the display layer is different.
As shown in FIG. 18, the display layer 400B included in the display sheet 21B of the present embodiment includes an adhesive layer 44 provided so as to cover the microcapsules 40 exposed from the binder layer 41 ′. Thereby, the circuit board 22 can be bonded to the display sheet 21 more strongly.
Also according to the third embodiment, the same effects as those of the first embodiment described above can be exhibited.

<Fourth embodiment>
Next, a fourth embodiment of the display sheet of the present invention will be described.
FIG. 19 is a cross-sectional view schematically showing a display sheet according to the fourth embodiment of the present invention.
Hereinafter, although the display sheet concerning 3rd Embodiment is demonstrated, it demonstrates centering around difference with 1st Embodiment mentioned above, The description is abbreviate | omitted about the same matter.

The display sheet according to the present embodiment has the same configuration as that of the first embodiment described above except that the configuration of the substrate (first substrate) is different.
As shown in FIG. 19, the substrate 100 </ b> C included in the display sheet 21 of the present embodiment is composed of a base material 12. That is, the color filter 7 is omitted from the embodiment shown in FIG. The display device 20 obtained using such a display sheet 21C can perform black and white display (display according to the color of the electrophoretic particles 5). The constituent material of the base 2 is not particularly limited, and for example, the same material (hard material) as that of the base 71 can be used.
According to the fourth embodiment, the same effect as that of the first embodiment described above can be exhibited.

  As mentioned above, although the manufacturing method of the display sheet and display apparatus of this invention was demonstrated based on embodiment of illustration, this invention is not limited to this, The structure of each part is arbitrary having the same function. It can be replaced with that of the configuration. In addition, any other component may be added to the present invention. The display sheet of the present invention may be a combination of any two or more configurations of the above embodiments.

  M1, M2 ... Resist film 9 ... Sealing part 10 ... Electrophoretic dispersion liquid 100, 100C ... Substrate (first substrate) 11 ... Base 12 ... Base 2 ... Base 20 ... Display device 201 ... Display surface 200 ... Glass substrate 21 ... Display sheet 21A, 21B, 21C ... Display sheet 22 ... Circuit board 210 ... Metal layer 220 ... Colored resin layer 240 ... Sheet member 3 ... Pixel electrode 300 ... Microcapsule coating solution 4 ... Common electrode 40, 40R, 40G, 40B ... Microcapsule 400, 400A, 400B ... Display layer 400a ... Side 401 ... Capsule body 41 ... Binder 41 '... Binder Layer 42, 42a, 42b ... Recess 44 ... Adhesive layer 5 ... Electrophoretic particles 5a ... White particles 5b ... Colored particles 00 ... Substrate 6 ... Liquid phase dispersion medium 600 ... Electronic paper 601 ... Main body 602 ... Display unit 7 ... Color filter 71 ... Base 72 ... Black matrix 721 ... Space 73, 73R, 73G, 73B ... Color material film 74 ... Protective layer 800 ... Display 801 ... Main body 802a ... Conveying roller pair 803 ... Hole 804 ... Transparent glass plate 805 ... Insertion port 806 ... Terminal part 807 ... Socket 808 ... Controller 809 ... Operation section

Claims (11)

Having a display layer comprising a plurality of storage portions in which at least one kind of particles is stored;
The display layer has a plurality of recesses opened on one surface of the display layer,
Each said recessed part is open | released to the side surface of the said display layer directly or through the other said recessed part. A flat hard substrate provided on the other surface side of the display layer;
The display sheet according to claim 1, wherein the Young's modulus of the substrate is 10 GPa or more.   The display sheet according to claim 2, wherein the substrate has a color filter that transmits light in a predetermined wavelength range.   The display sheet according to claim 1, wherein the depth of the recess is 5 μm or more. The accommodating portion has a spherical shape,
The display sheet according to claim 1, wherein the plurality of recesses are formed along outer walls of the plurality of storage units.   The display sheet according to claim 4, wherein at least a part of the concave portion is formed by an outer wall of the housing portion. A display layer including a first substrate, a plurality of storage portions provided on one surface side of the first substrate and encapsulating an electrophoretic dispersion liquid containing at least one kind of electrophoretic particles; and the display layer And a second substrate provided on a surface opposite to the first substrate, wherein the display device includes:
On one surface of the first substrate, there are a plurality of recesses that are open to the surface opposite to the first substrate, and each of the recesses opens to the side surface directly or via another recess. Forming the formed display layer;
By bonding the second substrate to the display layer and applying pressure to the display layer side, gas existing between the second substrate and the accommodating portion is crushed through the recess while the plurality of recesses are crushed. And a step of discharging from the side surface of the display layer to the outside. Each of the first substrate and the second substrate is hard,
The method for manufacturing a display device according to claim 7, wherein Young's modulus of each of the first substrate and the second substrate is 10 GPa or more.   The method for manufacturing a display device according to claim 7, wherein the second substrate is pressurized so that pressure is uniformly applied to the entire area of the second substrate.   The method for manufacturing a display device according to claim 7, wherein the second substrate is bonded to the display surface while maintaining a state parallel to the first substrate.   The method for manufacturing a display device according to claim 7, wherein the bonding of the second substrate and the display layer is performed in the atmosphere.

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