JP5098286B2 - Electrophoretic display device, electronic apparatus, and method of manufacturing electrophoretic display device - Google Patents

Description

  The present invention relates to an electrophoretic display device, an electronic apparatus, and a method for manufacturing an electrophoretic display device.

The conventional electrophoretic display device disclosed in Patent Document 1 is manufactured by pasting an electrophoretic sheet after forming an organic transistor on a substrate.
2005-201956 gazette

However, in the conventional method of manufacturing an electrophoretic display device, since the source electrode and the drain electrode are formed on the substrate and the semiconductor layer is formed thereon, the semiconductor layer is formed on the uneven surface, which is uniform. It was difficult to form a film with a sufficient thickness. In addition, since it is difficult to form a semiconductor layer having a flat surface, as a result, the interface with the gate insulating film formed thereover is not a flat surface, which causes variations in transistor characteristics. Was getting bigger.
Further, in the conventional manufacturing method, the adhesive layer for bonding the substrate on which the transistor is formed and the substrate having the electrophoretic layer is in direct contact with the electrophoretic layer. In general, the adhesive layer has low insulating properties, and when the adhesive layer is in direct contact with the electrophoretic layer, a leakage current with an adjacent pixel is caused, resulting in a deterioration in display quality.

  Therefore, an object of the present invention is to improve display quality and element characteristics of an electrophoretic display device.

An electrophoretic display device according to the present invention includes a common electrode layer formed on a first substrate, an electrophoretic layer formed on the common electrode layer, an insulating layer formed on the electrophoretic layer, and the insulating layer A first member including a gate electrode formed thereon, a gate insulating film formed so as to cover a surface including the gate electrode, and a semiconductor layer formed on the gate insulating film; and a second substrate A second member having a drain electrode integrally formed with the source electrode and the pixel electrode formed thereon, and disposed so that the semiconductor layer is sandwiched between the source electrode and the drain electrode; An adhesion between the first member and the second member, which is provided in the pixel electrode region in a region where the source electrode and the drain electrode are not formed, and bonds the first member and the second member With layers and That.
Accordingly, the first member and the second member are bonded via the adhesive layer, and the semiconductor substrate and the substrate having the electrophoretic layer are not bonded to each other in the insulating layer as in the prior art. There is no need to use a material having a high insulating property. For this reason, it is possible to prevent a leakage current from adjacent pixels caused by the adhesive material directly contacting the electrophoretic layer, thereby improving display quality.

  In addition, since the semiconductor layer is formed over the flat gate insulating film, the interface between the gate insulating film and the semiconductor layer is flattened. Therefore, carriers are smoothly transported in the channel, and the characteristics of the transistor can be improved.

  In addition, compared to the conventional case where the semiconductor layer is formed on a substrate with uneven source and drain electrodes, the coating film profile can be controlled more easily, and variation in transistor characteristics from pixel to pixel can be suppressed. Therefore, the display quality of the display device can be improved.

The electrophoretic display device according to the present invention includes a common electrode layer formed on a first substrate, an electrophoretic layer formed on the common electrode layer, an insulating layer formed on the electrophoretic layer, A first member having a gate electrode formed on the insulating layer, a gate insulating film formed so as to cover a surface including the gate electrode, and a semiconductor layer formed on the gate insulating film; A second member having a drain electrode integrally formed with a source electrode and a pixel electrode formed on a substrate, and disposed so that the semiconductor layer is sandwiched between the source electrode and the drain electrode; An area between the first member and the second member where the source electrode and the drain electrode are not formed is provided in the pixel electrode region , and bonds the first member and the second member. With an adhesive layer, The second substrate may have a recess in a region between the source electrode and the drain electrode, and the semiconductor layer may be accommodated in the recess so as not to contact the second substrate. Good.
Thereby, when the first member and the second member are bonded together, it is possible to prevent the second substrate and the semiconductor layer from being in direct contact with each other. Accordingly, formation of an interface trap level caused by the semiconductor layer being in contact with the second substrate can be prevented, and the characteristics of the transistor are further improved.

Furthermore, in the electrophoretic display device according to the present invention, a groove is formed in a part of the pixel electrode formed integrally with the drain electrode, and the adhesive layer is formed on the pixel electrode side with the groove as a boundary. It is desirable that
As a result, the adhesive forming the adhesive layer does not spread from the groove to the tip when the adhesive is applied or pressed, and wetting and spreading of the adhesive to the drain electrode can be prevented.

  The electronic device of the present invention includes all devices including the above-described electrophoretic display device as a display unit, and includes a display device, a television device, an electronic book, an electronic paper, a clock, a calculator, a mobile phone, and a portable information terminal. Etc.

In the method for manufacturing an electrophoretic display device according to the present invention, a common electrode layer is formed on a first substrate, an electrophoretic layer is formed on the common electrode layer, an insulating layer is formed on the electrophoretic layer, Forming a first member by forming a gate electrode on the insulating layer, forming a gate insulating film so as to cover a surface including the gate electrode, and forming a semiconductor layer on the gate insulating film; Forming a second member by forming a drain electrode in which a source electrode and a pixel electrode are integrally formed on a second substrate; and the source electrode and the drain of the second member Forming a bonding layer in the pixel electrode region in a region where no electrode is formed; and the first layer through the bonding layer so that the semiconductor layer is sandwiched between the source electrode and the drain electrode. Member and said second Those having a step of bonding the wood.

  Accordingly, the first member and the second member are bonded via the adhesive layer, and the semiconductor substrate and the substrate having the electrophoretic layer are not bonded to each other in the insulating layer as in the prior art. There is no need to use a material having a high insulating property. For this reason, it is possible to prevent a leakage current from adjacent pixels caused by the adhesive material directly contacting the electrophoretic layer, thereby improving display quality.

  In addition, since the semiconductor layer is formed over the flat gate insulating film, the interface between the gate insulating film and the semiconductor layer is flattened. Therefore, carriers are smoothly transported in the channel, and the characteristics of the transistor can be improved.

  In addition, compared to the conventional case where the semiconductor layer is formed on a substrate with uneven source and drain electrodes, the coating film profile can be controlled more easily, and variation in transistor characteristics from pixel to pixel can be suppressed. Therefore, the display quality of the display device can be improved.

In the method for manufacturing an electrophoretic display device according to the present invention, in the step of forming the second member, the second substrate is etched using the source electrode and the drain electrode as a mask. It is desirable to include a step of forming a recess in a region where the source electrode and the drain electrode are not provided on the substrate.
Thereby, when the first member and the second member are bonded together, it is possible to prevent the second substrate and the semiconductor layer from being in direct contact with each other.

Furthermore, in the method for manufacturing an electrophoretic display device according to the present invention, the step of forming the second member includes a step of forming a groove in a part of a pixel electrode formed integrally with the drain electrode, In the step of forming a layer, it is desirable to form the adhesive layer on the pixel electrode side with the groove as a boundary.
Thereby, the adhesive forming the adhesive layer does not spread from the groove to the tip, and wetting and spreading of the adhesive to the drain electrode can be prevented.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
Embodiment 1 FIG.
A method for manufacturing the electrophoretic display device 10 according to the first embodiment of the present invention will be described with reference to FIGS. FIGS. 1A to 1E and FIGS. 2A to 2D show cross sections of the electrophoretic display device 10.
(Creation of the first member)
First, the first member 100 including the common electrode layer, the electrophoresis layer, the insulating layer, the gate electrode, the gate insulating film, and the semiconductor layer is formed.
First, as shown in FIG. 1A, a transparent conductive film (common electrode layer) 102 is formed on a transparent substrate (first substrate) 101. The transparent substrate 101 is not particularly limited as long as it has transparency such as a glass substrate or a plastic substrate, but it is preferable to use a plastic substrate that is lightweight, flexible, and inexpensive. The transparent conductive film 102 is made of, for example, ITO (Indium Tin Oxide).

  Next, as illustrated in FIG. 1B, the electrophoretic layer 103 is formed over the transparent conductive film 102. The electrophoretic layer 103 is formed by uniformly applying microcapsules 1031 encapsulating an electrophoretic dispersion.

Hereinafter, a method for forming the electrophoretic layer 103 will be described.
The microcapsule 1031 can be created using an existing method. For example, various microencapsulation methods such as an interfacial polymerization method, an in-situ polymerization method, a phase separation method, an interfacial precipitation method, and a spray drying method can be used.
In addition, in order to obtain the microcapsules 1031 having a uniform size, for example, the microcapsules 1031 can be sieved or sorted using a filtration method, a specific gravity difference class method, or the like.
The average particle size of the microcapsule 1031 is preferably about 20 to 200 μm, and more preferably about 30 to 100 μm. By setting the average particle diameter of the microcapsules within the above range, the flatness of the electrophoretic layer 103 is improved. Thereby, the thickness of the insulating layer formed on the electrophoretic layer 103 described later can be reduced, and the electrophoresis can be controlled more favorably.

The microcapsule 1031 produced as described above is dispersed in a dispersion medium containing a binder material to prepare a microcapsule dispersion.
As the dispersion medium, a highly hydrophilic solvent (such as an aqueous solvent) is preferable. As the aqueous solvent, water such as distilled water and pure water is particularly preferable, but other lower alcohols such as methanol, ethanol, isopropanol, and butanol may also be used. Further, a lower hydrophobic substituent such as a methoxy group may be introduced into the lower alcohol. By using such an aqueous solvent, permeation of the solvent into the microcapsule 1031 is suppressed, and swelling and dissolution of the microcapsule 1031 due to permeation of the solvent are more reliably prevented.

The concentration (content) of the binder material in the microcapsule dispersion excluding the microcapsules is preferably 50 wt% or less, and more preferably about 0.05 to 25 wt%.
By setting the concentration of the binder material as described above, the viscosity of the microcapsule dispersion can be set to a suitable value, and in the step of supplying the microcapsule dispersion so as to fill the gaps of the microcapsules described later, The microcapsule can be easily and reliably moved.
The viscosity of the microcapsule dispersion is preferably about 1 to 1000 cP (25 ° C.), more preferably about 2 to 700 cP (25 ° C.).
In addition, the content of the microcapsule 1031 in the microcapsule dispersion is preferably about 10 to 80 wt%, and more preferably about 30 to 60 wt%.
When the content of the microcapsules 1031 is set in the above range, the microcapsules 1031 are easily arranged one by one (in a single layer) without overlapping in the thickness direction.

The microcapsule dispersion obtained as described above is supplied onto the transparent conductive film 102. As a method for supplying the microcapsule dispersion, various coating methods such as a spin coating method, a dip coating method, and a spray coating method can be used.
Further, the microcapsule dispersion liquid is applied so that the thickness of the microcapsule dispersion liquid becomes uniform, and more preferably, the microcapsules 1031 are arranged one by one without overlapping in the thickness direction. This is performed using a jig such as a squeegee for uniformly applying the dispersion liquid to the transparent substrate 101.

Next, as illustrated in FIG. 1C, the insulating layer 104 is formed over the electrophoretic layer 103.
Since the microcapsule 1031 has a spherical shape, when the microcapsule 1031 is disposed on the transparent conductive film 102, the surface is slightly uneven. The thickness of the insulating layer 104 may be set such that the unevenness can be reduced to such an extent that the formation of a gate electrode or a gate insulating film to be formed later is not affected. The insulating layer 104 is formed of the electrophoretic layer 103 and the pixel electrode. It is better to be as thin as possible. Preferably it is about 50 nm to 10 μm, more preferably about 200 nm to 2 μm.

  As a material of the insulating layer 104, any material can be used as long as it has insulating properties and smoothness and is formed by a method that does not damage the microcapsule 1031 during film formation. Both organic materials and inorganic materials can be used. For example, examples of the organic material include polymer films such as polymethyl methacrylate, polyvinyl phenol, polyimide, polystyrene, polyvinyl alcohol, and polyvinyl acetate, and parylene films. Examples of the inorganic material include silicon oxide, silicon nitride, aluminum oxide, and oxide. Examples thereof include metal oxides such as tantalum, and metal composite oxides such as barium strontium titanate and lead zirconium titanate. Moreover, it is also possible to use in combination of 2 or more of these.

  In the prior art, in this insulating layer 104, a separately formed semiconductor substrate and a substrate having an electrophoretic layer are bonded, and thus it is necessary to use an adhesive material for the insulating layer 104. Adhesive materials such as epoxy resins are generally difficult to remove impurities completely, and when such adhesive materials are in direct contact with the electrophoretic layer, they cause leakage current with adjacent pixels, resulting in display quality. It was the cause of the decline. However, in the present invention, it is not necessary to use an adhesive material for the insulating layer 104 and a highly insulating material can be used, so that display quality can be improved.

Next, as illustrated in FIG. 1D, the gate electrode 105 is formed over the insulating layer 104.
Examples of the material of the gate electrode 105 include Cr, Al, Ta, Mo, Nb, Cu, Ag, Au, Pt, Pd, In, Ni, Nd and alloys using these metals, InO ₂ , SnO ₂ , ITO. Conductive oxides such as polyaniline, polypyrrole, polythiophene, polyacetylene, etc., or acids such as hydrochloric acid, sulfuric acid, sulfonic acid, Lewis acids such as PF ₆ , AsF ₅ , FeCl ₃ , iodine, etc. And materials having conductivity, such as those added with dopants such as metal atoms such as halogen atoms, sodium and potassium, or conductive composite materials in which carbon black or metal particles are dispersed.
The gate electrode 105 is formed by performing photo-etching on the conductive film formed using the above material. Further, if the metal film is deposited on the insulating layer 104 through a metal through mask having a hole with a predetermined shape, the gate electrode 105 can be formed without etching.
Further, a polymer mixture containing conductive particles such as fine metal particles and graphite may be used as the material. In the case of forming the gate electrode 105 from such a solution, the electrode can be formed more easily and at low cost by performing solution patterning such as an ink jet method.
Further, when forming the gate electrode 105, it is desirable to simultaneously form an alignment mark for the last bonding of the first member 100 and the second member 200.

  Next, as illustrated in FIG. 1E, a gate insulating film 106 is formed over the gate electrode 105. The material of the gate insulating film 106 has an insulating property and is usually used as a gate insulating film of an organic transistor, that is, can form a good interface with a semiconductor layer formed on the gate insulating film 106. There is no particular limitation as long as it is, for example, a polymer film such as polyvinyl phenol, polyimide, polystyrene, polyvinyl alcohol, polymethyl methacrylate, polyvinyl acetate, or organic materials such as parylene film, silicon oxide, silicon nitride, aluminum oxide, tantalum oxide, etc. Inorganic materials such as metal oxides, metal composite oxides such as barium strontium titanate and lead zirconium titanate can be used. Moreover, you may use combining 1 type or 2 types or more of these.

Next, as illustrated in FIG. 2A, the semiconductor layer 107 is formed for each pixel over the gate insulating film 106. Examples of the material of the semiconductor layer 107 include poly (3-alkylthiophene), poly (3-hexylthiophene) (P3HT), poly (3-octylthiophene), poly (2,5-thienylenevinylene) (PTV), Poly (para-phenylene vinylene) (PPV), poly (9,9-dioctylfluorene) (PFO), poly (9,9-dioctylfluorene-co-bis-N, N '-(4-methoxyphenyl) -bis -N, N'-phenyl-1,4-phenylenediamine) (PFMO), poly (9,9-dioctylfluorene-co-benzothiadiazole) (BT), fluorene-triallylamine copolymer, triallylamine-based polymer, Fluorene-bithiophene co-weight such as poly (9,9-dioctylfluorene-co-dithiophene) (F8T2) Polymer organic semiconductor materials such as isomers, C60, metal phthalocyanines or substituted derivatives thereof, acene molecular materials such as anthracene, tetracene, pentacene, and hexacene, or α-oligothiophenes, specifically, quarter thiophene (4T), sexithiophene (6T), and low molecular organic semiconductors such as octathiophene can be used alone or in combination.
As a method for forming these organic semiconductors, general film forming methods such as a vapor deposition method, a CVD method, a casting method, a pulling method, a Langmuir Blodget method, a spray method, an ink jet method, and a silk screen method can be used.

  Before the semiconductor layer 107 is formed, a substrate surface treatment for forming the semiconductor layer 107 may be performed on the gate insulating film 106. This treatment includes, for example, a surface treatment using a surface modifier such as hexamethyldisilazane, cyclohexene, octadecyltrichlorosilane, an organic cleaning treatment using acetone, isopropyl alcohol, etc., an acid such as hydrochloric acid, sulfuric acid, acetic acid, or a hydroxylation. Examples include alkali treatment such as sodium, potassium hydroxide, calcium hydroxide, ammonia, UV ozone treatment, fluorination treatment, plasma treatment such as oxygen or argon, and formation of Langmuir Blodgett film, one of these or Two or more treatments can be performed. These treatments can be performed uniformly on the entire surface of the substrate, or may be performed only on a portion where the semiconductor layer 107 is formed or a portion where the semiconductor layer 107 is not formed.

Further, treatment for reducing interface traps between the gate insulating film 106 and the semiconductor layer 107 may be performed as necessary. Further, in order to increase the patterning accuracy, a lyophilic / liquid repellent region may be provided.
Although not shown, the gate electrode 105 and the corresponding semiconductor layer 107 are electrically connected. For example, a wiring made of a transparent electrode or the like is drawn from the gate electrode 105 to the outer peripheral portion of the insulating layer 104 to form a first conduction terminal. In addition, a second conduction terminal drawn from the semiconductor layer 107 is formed at a position corresponding to the first conduction terminal on the outer periphery of the gate insulating film 106. An anisotropic conductive layer is provided between the first conduction terminal and the second conduction terminal, thereby making electrical connection.

Next, the 2nd member 200 provided with the source electrode and the drain electrode is created.
FIG. 2B shows a state in which the source electrode 202 and the drain electrode 203 are formed over the substrate (second substrate) 201.

  As the substrate 201, a plastic substrate, a glass substrate, a silicon substrate, a metal substrate such as aluminum or stainless steel, a semiconductor substrate such as GaAs, and a substrate obtained by bonding these substrates can be used. In particular, a plastic substrate is preferable because it is flexible, lightweight, and inexpensive. As the plastic substrate, either a thermoplastic resin or a thermosetting resin may be used as a raw material. For example, polyolefins such as polyethylene, polypropylene, ethylene-propylene copolymer, ethylene-vinyl acetate copolymer (EVA), cyclic polyolefin, modified polyolefin, polyvinyl chloride, polyvinylidene chloride, polystyrene, polyamide, polyimide, polyamideimide, Polycarbonate, poly- (4-methylbenten-1), ionomer, acrylic resin, polymethyl methacrylate, acrylic-styrene copolymer (AS resin), butadiene-styrene copolymer, polio copolymer (EVOH), polyethylene Polyester such as terephthalate, polybutylene terephthalate, polyethylene naphthalate, precyclohexane terephthalate (PCT), polyether, polyetherketone, polyetheretherketone Polyetherimide, polyacetal, polyphenylene oxide, modified polyphenylene oxide, polyarylate, aromatic polyester (liquid crystal polymer), polytetrafluoroethylene, polyvinylidene fluoride, other fluororesins, styrene, polyolefin, polyvinyl chloride, polyurethane , Fluoroelastomers, chlorinated polyethylene, and other thermoplastic elastomers, epoxy resins, phenolic resins, urea resins, melamine resins, unsaturated polyesters, silicone resins, polyurethanes, etc., or copolymers and blends mainly composed of these Body, polymer alloy, etc., and a laminate in which one or more of these are laminated can be used.

First, the source electrode 202, the data line 206, the drain electrode 203, and the pixel electrode 205 are formed on the substrate 201. The source electrode 202 and the data line 206, and the drain electrode 203 and the pixel electrode 205 are integrally formed, respectively. Materials for the source electrode 202 (data line 206) and the drain electrode 203 (pixel electrode 205) include Cr, Al, Ta, Mo, Nb, Cu, Ag, Au, Pt, Pd, In, Ni, Nd, and their Alloys using metals, etc., conductive oxides such as InO ₂ , SnO ₂ , ITO, etc., conductive polymers such as polyaniline, polypyrrole, polythiophene, polyacetylene, and acids such as hydrochloric acid, sulfuric acid, sulfonic acid, PF ₆ , Materials having conductivity such as Lewis acids such as AsF ₅ and FeCl ₃ , dopants such as halogen atoms such as iodine, metal atoms such as sodium potassium, and conductive composite materials in which carbon black or metal particles are dispersed Is mentioned. For example, the source electrode 202 and the drain electrode 203 are formed by performing photo-etching on a conductive film formed using the above material. In addition, if a metal film is deposited on the substrate 201 through a metal through mask having a hole having a predetermined shape, the source electrode 202 and the drain electrode 203 can be formed without performing etching.
Further, a polymer mixture containing conductive particles such as fine metal particles and graphite may be used as the material. When the source electrode 202 and the drain electrode 203 are formed from such a solution, the electrode can be formed more easily and at low cost by performing solution patterning such as an ink jet method. Further, the source electrode 202 and the drain electrode 203 may be formed using different materials.

Next, an adhesive layer 204 is formed as illustrated in FIG.
The adhesive layer 204 is formed by applying an adhesive using an inkjet method, a dispensing method, or the like. Further, when the first member 100 and the second member 200 are bonded together, the semiconductor layer 107 and the adhesive layer 204 are formed so as not to contact each other. That is, it is desirable to avoid the regions of the source electrode 202 and the drain electrode 203 and to form the pixel electrode 205 region and the outer peripheral portion of the pixel electrode 205 region.
When thermocompression bonding or the like is performed when the first member 100 and the second member 200 are bonded together, the adhesive spreads slightly. However, the adhesive has a high conductivity because of many impurities, and the pixel spreads across adjacent electrodes. Cause leakage current. For this reason, it is preferable that the amount of the adhesive to be applied is the minimum necessary amount that can be accommodated in the pixel after the pressure bonding.

  There are no particular limitations on the material used as the adhesive, and curing agents such as amine curing agents, polyamide curing agents, acid and acid anhydride curing agents, imidazole curing agents, phenolic resins, urea resins, melamine resins, Epoxy resin / polyester adhesive, epoxy resin / nitrile rubber adhesive, epoxy resin / acrylic elastomer adhesive, and epoxy resin / urethane adhesive, emulsion adhesive, synthesis Known adhesive materials such as rubber adhesives, elastic adhesives, modified acrylate adhesives, acrylic adhesives, and silicone adhesives can be used. Further, polyolefins such as polyethylene and polypropylene, and thermoplastic resins such as vinyl acetate resins may be used.

  The adhesive layer 204 formed over the pixel electrode 205 forms a capacitive component between the pixel electrode 205 and the electrophoretic layer 103 when the first member 100 and the second member 200 are bonded to each other. Is preferably as thin as possible while ensuring the necessary adhesiveness, and preferably has a thickness of about 100 nm to 2 μm in the state after bonding.

  In addition, by mixing a conductive material into the adhesive, the adhesive itself can be used as a part of the pixel electrode. Thereby, the display quality of the display device can be improved. As such a conductive adhesive, for example, a conductive material (conductive particles) such as gold, silver, nickel, carbon, etc. in a non-conductive material such as a glass material, a rubber material, and a polymer material. Various composite materials mixed with conductivity, that is, conductive materials in conductive rubber, epoxy, urethane, acrylic and other adhesive compositions in which conductive materials are mixed in rubber materials Mixed conductive adhesive or conductive paste, polyolefin, polyvinyl chloride, polystyrene, ABS resin, nylon (polyamide), ethylene vinyl acetate copolymer, polyester, acrylic resin, epoxy resin, urethane resin, etc. Examples thereof include a conductive resin in which a conductive material is mixed in a resin.

Finally, as shown in FIG. 2D, the first member 100 and the second member 200 are bonded together to form the electrophoretic display device 10.
When the first member 100 and the second member 200 are bonded together, the first member 100 and the second member 200 are bonded together in alignment with the alignment marks formed when the gate electrode 105 is formed, and adjusted so that both wiring patterns match.

  As described above, according to the first embodiment of the present invention, since the first member 100 and the second member 200 are bonded via the adhesive layer 204, the conventional insulating layer 104 and the semiconductor substrate There is no need to use an adhesive material for the insulating layer 104 as in the case of bonding a substrate having an electrophoretic layer, and a highly insulating material can be used. For this reason, it is possible to prevent a leakage current from adjacent pixels caused by the adhesive material directly contacting the electrophoretic layer, thereby improving display quality.

  In addition, according to Embodiment 1, the semiconductor layer 107 is formed over the flat gate insulating film 106, so that the interface between the gate insulating film 106 and the semiconductor layer 107 is flattened. Therefore, carriers are smoothly transported in the channel, and the characteristics of the transistor can be improved.

  In addition, compared to the conventional case where the semiconductor layer 107 is formed on a substrate with uneven source and drain electrodes, the coating film profile can be controlled more easily, and variation in transistor characteristics from pixel to pixel can be suppressed. Therefore, the display quality of the display device can be improved.

Note that since the adhesive preferentially spreads over the pixel electrode with good wettability, a part of the pixel electrode 205 is removed before applying the adhesive, and the drain electrode 203 is in contact with the semiconductor layer 107. The spread of the adhesive may be prevented. FIG. 3 is a plan view of the electrophoretic display device 10. As shown in the figure, by removing a part around the boundary between the drain electrode 203 and the pixel electrode 205 to form the groove A and then applying the adhesive, the adhesive does not spread from the groove A to the tip, It is possible to prevent the adhesive from spreading on the drain electrode 203.
Moreover, when forming an electrode pattern, you may design to the pattern which can prevent a wetting spread. Further, in order to control the wetting and spreading, a part of the electrode may be subjected to a liquid repellent treatment.

(Example)
(First member 100)
First, the first member 100 is created.
(Transparent substrate 101)
A polyethylene naphthalate substrate (manufactured by Teijin DuPont Films, "Teonex Q65" (registered trademark)) to be the transparent substrate 101 is subjected to degreasing treatment by ultrasonic cleaning for 30 minutes using isopropyl alcohol as a solvent.

(Transparent conductive film 102)
Next, a transparent conductive film 102 (ITO) with a thickness of 200 nm is uniformly formed on the entire surface of the transparent substrate 101 that has been degreased.

(Electrophoresis layer 103)
Next, a microcapsule in which fine particles of carbon black as a black particle and titanium oxide fine particles as a white particle are dispersed in gum arabic is applied on the ITO of the substrate, and a squeegee (a plate-shaped jig) is placed at a distance of 100 μm from the substrate. A uniform layer (electrophoretic layer 103) of microcapsules is formed by passing the film while maintaining the above.

(Insulating layer 104)
Next, the substrate on which the microcapsule layer is formed is placed in a vacuum chamber, and a parylene film (insulating layer 104) is formed to a thickness of 500 nm at room temperature. Thus, the substrate surface on which the gate electrode 105 is formed can be planarized.

(Gate electrode 105)
Next, the surface of the parylene film is subjected to UV ozone treatment for 5 minutes to improve the lyophilicity of the surface. Next, a gold fine particle dispersion liquid (manufactured by Vacuum Metallurgy Co., Ltd., trade name “Perfect Gold”) in which gold fine particles having a diameter of 10 nm are dispersed in toluene is applied to the parylene film surface in a pattern by an ink jet method and then baked at 100 ° C. for 1 hour. To form a gate electrode 105 (and a scanning line). At this time, an alignment pattern for bonding with the second member 200 is simultaneously formed.

(Gate insulating film 106)
Next, as the gate insulating film 106, a SiO ₂ film is uniformly formed with a thickness of 200 nm by plasma CVD.

(Semiconductor layer 107)
Next, a coating solution in which poly (3-hexylthiophene) was dissolved in xylene at a concentration of 0.5 wt% was prepared, and the coating solution was applied only to the portion on the gate insulating film 106 where the transistor was formed using an inkjet coating apparatus. Thereafter, drying is performed at 100 ° C. for 10 minutes to remove xylene as a solvent, and an organic semiconductor layer (semiconductor layer 107) having a thickness of 100 nm is formed.

(Second member 200)
Next, a second member 200 to be bonded to the first member 100 is created.
(Substrate 201, source electrode 202, drain electrode 203)
A flexible substrate in which a 200 nm SiN insulating film is formed on a 100 μm thick stainless steel substrate is used as the substrate 201. A gold thin film having a thickness of 100 nm is formed on this substrate by sputtering, and photoetching is performed to pattern the source electrode 202 (data line 206) and drain electrode 203 (pixel electrode 205), and the alignment mark for bonding. Form.

(Adhesive layer 204)
A liquid in which a dispersion of PEDOT / PSS, which is a conductive polymer, is mixed in an epoxy resin is applied to the pixel electrode region on the substrate using a dispenser, and the solvent is baked on a hot plate at 40 ° C. for 10 minutes. The adhesive layer 204 is formed by removing.

  Finally, the first member 100 and the second member 200 are bonded together with alignment marks, and the electrophoretic display device 10 is completed.

Embodiment 2. FIG.
4A and 4B are views showing a method for manufacturing the electrophoretic display device 10 according to the second embodiment of the present invention. As shown in FIG. 4A, in Embodiment 2, after the source electrode 202 (data line 206) and the drain electrode 203 (pixel electrode 205) are formed over the substrate 201 of the second member 200, the electrodes are masked. As a result of etching the substrate 201, a recess 207 is formed in a region where no electrode is provided. Accordingly, as illustrated in FIG. 4B, when the first member 100 and the second member 200 are bonded to each other, the substrate 201 and the semiconductor layer 107 can be prevented from being in direct contact with each other.

  Accordingly, holes and electrons can be doped at the interface between the semiconductor layer 107 and the substrate 201, and interface trap levels can be prevented, so that the characteristics of the transistor can be improved.

Any method can be used for etching the substrate 201 as long as the source electrode 202 and the drain electrode 203 are not damaged. Wet etching with an acid such as hydrofluoric acid, nitric acid, hydrochloric acid, or sulfuric acid, sodium hydroxide, Wet etching with bases such as potassium oxide, calcium hydroxide, ammonia, etc., wet etching with aromatic solvents, ketone solvents, alcohol solvents, organic solvents, dry etching using oxygen plasma, argon plasma, CF ₄ plasma, etc. Can be used.

Electronic Device FIG. 5 is a perspective view illustrating a specific example of an electronic device to which the electrophoretic display device of the present invention is applied. FIG. 5A is a perspective view illustrating an electronic book which is an example of the electronic apparatus. The electronic book 1000 includes a book-shaped frame 1001, a cover 1002 that can be rotated (openable and closable) with respect to the frame 1001, an operation unit 1003, and the electrophoretic display device of the present invention. Display unit 1004.

  FIG. 5B is a perspective view illustrating a wrist watch that is an example of an electronic apparatus. The wristwatch 1100 includes a display unit 1101 configured by the electrophoretic display device of the present invention.

  FIG. 5C is a perspective view illustrating electronic paper which is an example of the electronic apparatus. This electronic paper 1200 includes a main body portion 1201 formed of a rewritable sheet having the same texture and flexibility as paper, and a display portion 1202 formed of an electrophoretic display device of the present invention.

  Note that the range of electronic devices to which the electrophoretic display device of the present invention can be applied is not limited to this, and includes a wide range of devices that utilize changes in visual color tone accompanying the movement of charged particles.

1A to 1E are diagrams showing a method for manufacturing an electrophoretic display device according to Embodiment 1. FIG. 2A to 2D are diagrams showing a method for manufacturing the electrophoretic display device according to the first embodiment. FIG. 3 is a diagram showing an electrophoretic display device according to a modification of the first embodiment. 4A and 4B are diagrams illustrating a method for manufacturing the electrophoretic display device 10 according to the second embodiment. 5A to 5C are diagrams showing examples of electronic devices according to the present invention.

Explanation of symbols

10 electrophoretic display device, 100 first member, 101 transparent substrate, 102 transparent conductive film, 103 electrophoretic layer, 1031 microcapsule, 104 insulating layer, 105 gate electrode, 106 gate insulating film, 107 semiconductor layer, 200 second Member 201 substrate 202 source electrode 203 drain electrode 204 adhesive layer 205 pixel electrode 206 data line 207 recess

Claims (7)

A common electrode layer formed on the first substrate; an electrophoretic layer formed on the common electrode layer; an insulating layer formed on the electrophoretic layer; a gate electrode formed on the insulating layer; A first member including a gate insulating film formed so as to cover a surface including the gate electrode, and a semiconductor layer formed on the gate insulating film;
A second member having a drain electrode integrally formed with a source electrode and a pixel electrode formed on a second substrate, and arranged so that the semiconductor layer is sandwiched between the source electrode and the drain electrode When,
An area between the first member and the second member in which the source electrode and the drain electrode are not formed is provided in the pixel electrode region , and the first member and the second member are bonded. An electrophoretic display device comprising an adhesive layer. A common electrode layer formed on the first substrate; an electrophoretic layer formed on the common electrode layer; an insulating layer formed on the electrophoretic layer; a gate electrode formed on the insulating layer; A first member having a gate insulating film formed to cover the surface including the gate electrode, and a semiconductor layer formed on the gate insulating film;
A second member having a drain electrode integrally formed with a source electrode and a pixel electrode formed on a second substrate, and arranged so that the semiconductor layer is sandwiched between the source electrode and the drain electrode When,
An area between the first member and the second member in which the source electrode and the drain electrode are not formed is provided in the pixel electrode region , and the first member and the second member are bonded. An adhesive layer
The second substrate has a recess in a region between the source electrode and the drain electrode, and the semiconductor layer is accommodated in the recess so as not to contact the second substrate. Electrophoretic display device. Are grooves formed in a part of the drain electrode and the pixel electrode which is formed integrally,
The electrophoretic display device according to claim 1, wherein the adhesive layer is formed on the pixel electrode side with the groove as a boundary.   An electronic apparatus comprising the electrophoretic display device according to any one of claims 1 to 3. Forming a common electrode layer on the first substrate; forming an electrophoretic layer on the common electrode layer; forming an insulating layer on the electrophoretic layer; forming a gate electrode on the insulating layer; Forming a first member by forming a gate insulating film so as to cover a surface including the gate electrode, and forming a semiconductor layer on the gate insulating film;
Forming a second member by forming a drain electrode in which a source electrode and a pixel electrode are integrally formed on a second substrate;
Forming an adhesive layer on the pixel electrode region in a region where the source electrode and the drain electrode of the second member are not formed;
A method of manufacturing an electrophoretic display device comprising a step of bonding the first member and the second member through the adhesive layer so that the semiconductor layer is sandwiched between the source electrode and the drain electrode . The step of forming the second member includes
Etching the second substrate using the source electrode and the drain electrode as a mask, and forming a recess in a region of the second substrate where the source electrode and the drain electrode are not provided. The method for manufacturing an electrophoretic display device according to claim 5, wherein: The step of forming the second member includes
Includes the step of forming a groove in a portion of the pixel electrode formed integrally with the drain electrode,
In the step of forming the adhesive layer,
The method for manufacturing an electrophoretic display device according to claim 5, wherein the adhesive layer is formed on the pixel electrode side with the groove as a boundary.

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