JP5446751B2 - Multilayer structure, electronic element, electronic element array, image display medium, and image display apparatus - Google Patents

Description

  The present invention relates to a laminated structure having a laminated structure in which a conductor layer is formed in a region irradiated with ultraviolet rays of a wettability changing layer containing a material whose surface free energy changes by irradiating ultraviolet rays, an electronic device, The present invention relates to an electronic element array, an image display medium, and an image display device.

  In recent years, organic thin film transistors using organic semiconductor materials have been intensively studied. Advantages of using an organic semiconductor material include high flexibility, a large area, a simplified manufacturing process, and a low cost manufacturing apparatus.

The current on / off ratio is used as a parameter indicating the characteristics of the organic thin film transistor. In the organic thin film transistor, on-current _{I ds} flowing between the source and drain electrodes in the saturation region, the formula _{I ds = μC in W (V} G -V TH) 2 / 2L
(Wherein μ is the field effect mobility, C _in is the capacitance per unit area of the gate insulating film, and the formula C _in = εε ₀ / d
(Where ε is the relative dielectric constant of the gate insulating film, ε ₀ is the vacuum dielectric constant, and d is the thickness of the gate insulating film.)
W is the channel width, L is the channel length, V _G is the gate voltage, and V _TH is the threshold voltage. )
It is represented by From this equation, it can be seen that it is effective to increase μ, decrease L, and increase W in order to increase the on-current. At this time, μ largely depends on the characteristics of the organic semiconductor material. On the other hand, L and W are derived from the structure of the organic thin film transistor. In general, in order to reduce L, the distance between the source and drain electrodes is reduced. However, since organic thin film transistors have a small μ, L is required to be 10 μm or less, preferably 5 μm or less.

  Such a source / drain electrode pattern is desired to be formed by ink jet printing. When the ink jet printing method is used, a pattern can be directly drawn, so that the material use efficiency is increased, and the manufacturing process can be simplified and the cost can be reduced. However, in the inkjet printing method, it is difficult to reduce the discharge amount, and it is difficult to form a pattern of 30 μm or less in consideration of landing accuracy due to mechanical errors and the like.

  Therefore, after changing the surface free energy by irradiating the wettability changing layer containing the material whose surface free energy changes by irradiating the ultraviolet ray, the source wettability changing layer is applied to the wettability changing layer using the inkjet printing method. A method of forming a drain electrode pattern is known. However, even if a high-power ultraviolet lamp is used, a long irradiation time is required. As a result, there is a problem that the tact time becomes long and simplification of the manufacturing process and cost reduction cannot be expected. In addition, there is a problem that the insulating property of the wettability changing layer is lowered by the ultraviolet rays irradiated when changing the surface free energy.

  Therefore, in Patent Document 1, an organic thin film transistor is formed using a material having a main chain and a side chain, the main chain is a soluble polyimide, and the side chain has two or more sites whose bonds are cleaved when absorbing the ultraviolet rays. It is manufactured.

  On the other hand, in order to reduce the power consumption, it is necessary to further reduce the thickness of the organic thin film transistor, and it is necessary to further suppress the decrease in the insulating property of the wettability changing layer due to the ultraviolet rays irradiated when changing the surface free energy. .

  In view of the above-described problems of the prior art, the present invention provides a laminated structure capable of suppressing a decrease in insulating properties of a wettability changing layer due to ultraviolet rays irradiated when changing the surface free energy, and the laminated structure. It is an object to provide an electronic device, an electronic device array, an image display medium, and an image display device.

The invention according to claim 1, in the laminated structure, on a substrate, the ultraviolet are wettability variable layer formed comprises a material that changes the surface free energy by irradiating, said of the wettability changing layer have a layered structure in which conductor layer in a region where ultraviolet rays are irradiated is formed, the material whose surface free energy changes by irradiating the ultraviolet rays, the general formula

（式中、ｎ_１及びｎ_２は、重合度であり、ｎ_１とｎ_２の和に対するｎ_２の比が１％以上３０％以下である。）
で表される有機溶媒に可溶なポリイミド又は一般式

（式中、ｎ _１ 及びｎ _２ は、重合度であり、ｎ _１ とｎ _２ の和に対するｎ _２ の比が１％以上３０％以下である。）
で表される有機溶媒に可溶なポリイミドであることを特徴とする。

(Wherein, _{n 1} and _{n 2} are the degree of polymerization, the ratio of _{n 2} to the sum of _{n 1} and _{n 2} is less than 1% to 30%.)
Soluble polyimide or general formula organic solvent in you express

(Wherein, _{n 1} and _{n 2} are the degree of polymerization, the ratio of _{n 2} to the sum of _{n 1} and _{n 2} is less than 1% to 30%.)
It is a polyimide soluble in the organic solvent represented by these.

According to a second aspect of the present invention, an electronic device includes the laminated structure according to the first aspect.

According to a third aspect of the present invention, in the electronic device according to the second aspect , a semiconductor layer and an insulator layer are further formed on the substrate .

According to a fourth aspect of the present invention, in the electronic device according to the third aspect , the semiconductor layer includes an organic semiconductor material.

According to a fifth aspect of the present invention, in the electronic device according to the third or fourth aspect , the laminated structure is formed on the insulator layer.

According to a sixth aspect of the present invention, in the electronic device according to any one of the third to fifth aspects, the wettability changing layer also serves as the insulator layer.

According to a seventh aspect of the present invention, in the electronic device according to any one of the third to sixth aspects, a plurality of the laminated structures are provided.

According to an eighth aspect of the present invention, an electronic element array includes a plurality of the electronic elements according to any one of the second to seventh aspects.

According to a ninth aspect of the present invention, in the image display medium, the electronic element array according to the eighth aspect is provided.

According to a tenth aspect of the present invention, an image display apparatus includes the image display medium according to the ninth aspect.

  ADVANTAGE OF THE INVENTION According to this invention, the laminated structure which can suppress the fall of the insulation of the wettability change layer by the ultraviolet-ray irradiated when changing a surface free energy, the electronic device and electronic device array which have this laminated structure An image display medium and an image display device can be provided.

It is sectional drawing which shows an example of the laminated structure of this invention. It is sectional drawing which shows the 1st example of the electronic device of this invention. It is sectional drawing which shows the 2nd example of the electronic device of this invention. It is sectional drawing which shows the 3rd example of the electronic device of this invention. It is a figure which shows an example of the electronic element array of this invention. It is sectional drawing which shows an example of the image display medium of this invention. It is a perspective view which shows an example of the image display apparatus of this invention.

  Next, the form for implementing this invention is demonstrated with drawing.

  FIG. 1 shows an example of a laminated structure of the present invention. In the laminated structure 10, a wettability changing layer 12 including a material whose surface free energy changes when irradiated with ultraviolet rays is formed on a substrate 11. At this time, the wettability changing layer 12 includes an ultraviolet irradiation region 12a whose surface free energy is increased by being irradiated with ultraviolet rays, and an ultraviolet non-irradiation region 12b which is not irradiated with ultraviolet rays. An ultraviolet non-irradiation region 12b having a width of 1 to 5 μm is formed between the ultraviolet irradiation regions 12a. Moreover, the conductor layer 13 is formed on the ultraviolet irradiation region 12a of the wettability changing layer 12, and has a laminated structure. Thereby, the conductor layer 13 having a fine pattern can be easily formed.

  Although it does not specifically limit as a material which comprises the board | substrate 11, Glass; Resins, such as polyester, polycarbonate, polyacrylate, polyether sulfone, polyethylene terephthalate, polyethylene naphthalate; Metals, such as SUS, etc. are mentioned, Flexibility is requested | required In that case, a resin is preferred.

  A material whose surface free energy changes by irradiating with ultraviolet rays is a general formula.

（式中、Ａは、一般式

(Where A is a general formula

（式中、Ｒ_１、Ｒ_２、Ｒ_３及びＲ_４は、それぞれ独立に、水素原子、フルオロ基又は炭素数が１〜４のアルキル基である。）
で表される基又は化学式

(Wherein R ₁ , R ₂ , R ₃ and R ₄ are each independently a hydrogen atom, a fluoro group or an alkyl group having 1 to 4 carbon atoms.)
Group or chemical formula

で表される基であり、Ｂ_１は、化学式

B ₁ is a group represented by the chemical formula

で表される基であり、Ｂ_２は、一般式

B ₂ is a group represented by the general formula

（式中、ｍは、５〜１３の整数である。）
で表される基であり、ｎ_１及びｎ_２は、それぞれ独立に、自然数であり、ｎ_１とｎ_２の和に対するｎ_２の比が１〜３０％である。）
で表されるポリアミド酸を脱水閉環反応させることにより得られる有機溶媒に可溶なポリイミド（以下、可溶性ポリイミドという）である。このとき、ｐが５未満であると、濡れ性変化層１２に紫外線を照射することによる表面自由エネルギーの変化が不十分となり、１３を超えると、可溶性ポリイミドの有機溶媒に対する溶解性が不十分となる。また、Ｒ_１、Ｒ_２、Ｒ_３及びＲ_４における炭素数が１〜４の有機基としては、メチル基、エチル基等が挙げられる。なお、濡れ性変化層１２は、基板１１上に、可溶性ポリイミドの溶液を塗布した後、焼成することにより形成される。

(In the formula, m is an integer of 5 to 13.)
In a group represented by, _{n 1} and _{n 2} are independently a natural number, the ratio of _{n 2} to the sum of _{n 1} and _{n 2} is 1 to 30%. )
Is a polyimide soluble in an organic solvent (hereinafter referred to as soluble polyimide) obtained by subjecting the polyamic acid represented by At this time, if p is less than 5, the change in surface free energy by irradiating the wettability changing layer 12 with ultraviolet light becomes insufficient, and if it exceeds 13, the solubility of soluble polyimide in an organic solvent is insufficient. Become. Examples of the organic group having 1 to 4 carbon atoms in R ₁ , R ₂ , R ₃ and R ₄ include a methyl group and an ethyl group. The wettability changing layer 12 is formed by applying a soluble polyimide solution on the substrate 11 and then baking it.

At this time, since the polyamic acid has A, a soluble polyimide can be obtained, and the wettability changing layer 12 having excellent solvent resistance can be formed. Moreover, since the carbonyl group of A is not conjugated with a benzene ring or the like, the wettability changing layer 12 having excellent insulating properties can be formed. A is preferably a group represented by the general formula (A-1) or a group represented by the chemical formula (A-2), and particularly preferably a group represented by the chemical formula (A-3). In addition, A may contain 2 or more types of groups. At this time, the content of the group represented by the chemical formula (A-3) in A is preferably 50 to 100 mol%. Moreover, A in the structural unit having a polymerization degree of n ₁ may be different from A in the structural unit having a polymerization degree of n ₂ .

B ₁ represents, since less polar, soluble polyimide is obtained in combination with B _2. Further, when the wettability changing layer 12 is used as a gate insulating film of an organic thin film transistor, it is possible to reduce gate leakage current and suppress deterioration of insulation when the gate voltage is increased. On the other hand, B ₂ can reduce the surface free energy of the wettability changing layer 12, that is, make it water repellent. B ₁ and B ₂ may each independently contain two or more groups.

the ratio of n ₂ to the sum of n ₁ and n ₂ is less than 1% change in the surface free energy by irradiating ultraviolet rays of the wettability changing layer 12 becomes insufficient, and when it exceeds 30%, the soluble polyimide Cannot be obtained. The ratio of _{n 2} to the sum of _{n 1} and _{n 2} is preferably 5 to 20 mol%.

  The polyamic acid represented by the general formula (1) has the general formula

で表されるテトラカルボン酸二無水物と、一般式

A tetracarboxylic dianhydride represented by the general formula

で表されるジアミンを、有機溶媒中で開環重付加反応させることにより得られる。なお、Ａ及びＢは、一般式（１）の定義と同様である。

Is obtained by ring-opening polyaddition reaction in an organic solvent. In addition, A and B are the same as the definition of General formula (1).

  A method for subjecting tetracarboxylic dianhydride and diamine to a ring-opening polyaddition reaction in an organic solvent is not particularly limited, but a solution obtained by dispersing or dissolving diamine (or tetracarboxylic dianhydride) in an organic solvent is stirred. While the tetracarboxylic dianhydride (or diamine) is dispersed or dissolved in an organic solvent as required, a method of adding and performing a ring-opening polyaddition reaction, while stirring the organic solvent, Examples thereof include a method in which acid dianhydride and diamine are dispersed or dissolved in an organic solvent as necessary, and then alternately added to cause ring-opening polyaddition reaction. In addition, when tetracarboxylic dianhydride and / or diamine consists of two or more types, you may carry out a ring-opening polyaddition reaction in the state which mixed several types of components previously, and you may carry out a ring-opening polyaddition reaction one by one. .

  The temperature at which the ring-opening polyaddition reaction of tetracarboxylic dianhydride and diamine in an organic solvent is usually -20 to 150 ° C, preferably 0 to 80 ° C. When this temperature is less than -20 ° C, the ring-opening polyaddition reaction may take a long time, and when it exceeds 150 ° C, a high molecular weight polyamic acid may not be obtained.

  The ratio of the total mass of tetracarboxylic dianhydride and diamine to the total mass of the polymerization system is usually 1 to 50%, preferably 5 to 30% by mass. When this ratio is less than 1%, a high molecular weight polyamic acid may not be obtained, and when it exceeds 50%, the viscosity of the polymerization system may increase and uniform stirring may not be achieved. In the initial stage, the ring-opening polyaddition reaction may be carried out with this ratio being large, and then diluted with an organic solvent.

  The organic solvent used for synthesizing the polyamic acid is not particularly limited as long as the produced polyamic acid can be dissolved. N, N-dimethylformamide, N, N-dimethylformacetamide, N-methyl -2-pyrrolidone, N-methylcaprolactam, dimethyl sulfoxide, tetramethyl urea, pyridine, dimethyl sulfone, hexamethyl sulfoxide, γ-butyrolactone and the like may be used, and two or more may be used in combination. The organic solvent may contain a solvent in which the polyamic acid does not dissolve within a range in which the produced polyamic acid does not precipitate.

  The molar ratio of diamine to tetracarboxylic dianhydride when synthesizing polyamic acid is usually 0.5 to 1.5, and the closer the molar ratio is to 1, the larger the molecular weight of polyamic acid.

  The method for subjecting the polyamic acid represented by the general formula (1) to the dehydration ring-closing reaction is not particularly limited, but it is difficult to reduce the molecular weight of the polyimide, and the reaction rate of the dehydration ring-closing reaction is easily controlled. And a method using carboxylic anhydride is preferable. Specifically, the polyamic acid is stirred in an organic solvent for 1 to 100 hours in the presence of a basic catalyst and carboxylic anhydride.

  Although it does not specifically limit as a basic catalyst, A pyridine, a triethylamine, a trimethylamine, a tributylamine, a trioctylamine etc. are mentioned, Especially, since it has moderate basicity to advance a spin-drying | dehydration ring-closing reaction, a pyridine is preferable.

  The addition amount of the basic catalyst is usually 0.5 to 30 times equivalent and preferably 2 to 20 times equivalent to the amide group of the polyamic acid.

  Although it does not specifically limit as carboxylic anhydride, Acetic anhydride, trimellitic anhydride, pyromellitic anhydride, etc. are mentioned, Especially, since a polyimide can be refine | purified easily, acetic anhydride is preferable.

  The amount of carboxylic anhydride added is usually 1 to 50 times equivalent and preferably 3 to 30 times equivalent to the amide group of the polyamic acid.

  As the organic solvent used when the polyamic acid is subjected to a dehydration ring-closing reaction, an organic solvent used when synthesizing the polyamic acid can be used.

  The temperature at which the polyamic acid is subjected to a dehydration ring-closing reaction is usually -20 to 250 ° C, preferably 0 to 180 ° C. When this temperature is less than −20 ° C., it may take a long time for the dehydration ring-closing reaction, and when it exceeds 250 ° C., a high molecular weight polyimide may not be obtained.

  The soluble polyimide reaction liquid obtained as described above may be applied when the wettability changing layer 12 is formed. However, the reaction liquid contains impurities such as a basic catalyst. It is preferable to apply a solution of a soluble polyimide dissolved in a solvent after purifying the polyimide.

  When purifying polyimide, the reaction solution is put into a stirring poor solvent to precipitate the polyimide, followed by filtration and washing with the poor solvent. Examples of the poor solvent include, but are not limited to, water; alcohols such as methanol and ethanol; hydrocarbons such as hexane, heptane and toluene. The recovered polyimide can be powdered by drying at room temperature or heating under normal pressure or reduced pressure. Further, the liquid obtained by dissolving the obtained powder in an organic solvent is poured into a poor solvent that is being stirred in the same manner as described above, and after the polyimide is precipitated, it is filtered and washed with the poor solvent. By repeating 2 to 10 times, impurities can be removed. At this time, if two or more kinds of solvents such as alcohol and hydrocarbon are used as the poor solvent, impurities can be further removed.

The reaction rate of the polyamic acid dehydration ring-closing reaction is preferably 50 to 100%, more preferably 80 to 100%, and particularly preferably 90 to 100%. When the reaction rate is less than 50%, when the wettability changing layer 12 is used as a gate insulating film of an organic thin film transistor, the wettability changing layer 12 may not be able to form a good interface with the organic semiconductor layer. As a result, the variation of the threshold voltage of the organic thin film transistor becomes large. The reaction rate of the polyamic acid dehydration ring-closing reaction is to dissolve in dimethyl sulfoxide (DMSO) -d ₆ , measure ¹ H-NMR of the soluble polyimide, and calculate the ratio of the remaining amide groups from the peak area ratio. Can be measured.

  The dehydration ring-closing reaction between the amide group and the carboxyl group remaining in the soluble polyimide can be advanced by baking after applying a solution of the soluble polyimide.

The weight average molecular weight of the soluble polyimide is usually 2 × 10 ³ to 2 × 10 ⁵ from the viewpoint of easy handling and stability of the characteristics of the wettability changing layer 12, and 5 × 10 ^{3 to} 5 × 10 ⁴ is preferable. The weight average molecular weight of the soluble polyimide can be measured using GPC (gel permeation chromatography).

  The solution of soluble polyimide may contain 2 or more types of soluble polyimide.

  The solvent contained in the soluble polyimide solution is not particularly limited as long as the soluble polyimide can be dissolved. N, N-dimethylformamide, N, N-dimethylacetamide, 2-pyrrolidone, N-methyl-2-pyrrolidone N-ethyl-2-pyrrolidone, N-vinyl-2-pyrrolidone, N-methylcaprolactam, dimethyl sulfoxide, tetramethylurea, pyridine, γ-butyrolactone and the like may be used in combination.

  Other solvents may be added to the soluble polyimide solution for the purpose of adjusting the surface tension, polarity, boiling point, ensuring the flatness of the wettability changing layer 12, and improving the wettability to the substrate 11. Examples of such solvents include ethyl cellosolve, butyl cellosolve, ethyl carbitol, butyl carbitol, ethyl carbitol acetate, ethylene glycol; 1-methoxy-2-propanol, 1-ethoxy-2-propanol, 1-butoxy-2- Propanol, 1-phenoxy-2-propanol, propylene glycol monoacetate, propylene glycol diacetate, propylene glycol-1-monomethyl ether-2-acetate, propylene glycol-1-monoethyl ether-2-acetate, dipropylene glycol, 2 -Propylene glycol derivatives such as-(2-methoxypropoxy) propanol, 2- (2-ethoxypropoxy) propanol, 2- (2-butoxypropoxy) propanol; Le, ethyl lactate, n- propyl lactate, n- butyl, etc. lactic esters such as lactic acid isoamyl. These may be used alone or in combination.

  N, N-dimethylformamide, N, N-dimethylacetamide, N-methyl-2-pyrrolidone in all solvents from the viewpoint of improving the storage stability of the soluble polyimide solution and the uniformity of the thickness of the wettability changing layer 12 The content of one or more solvents selected from γ-butyrolactone and dimethyl sulfoxide is preferably 20 to 80% by mass.

  The content of the soluble polyimide in the soluble polyimide solution can be appropriately selected according to the specifications of the coating apparatus and the thickness of the wettability changing layer 12, but is usually 0.1 to 30% by mass, 1-10 mass% is preferable.

  The soluble polyimide solution may further contain additives such as a silane coupling agent and an epoxy compound for the purpose of improving the adhesion to the substrate 11.

  As the silane coupling agent, 3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, 2-aminopropyltrimethoxysilane, 2-aminopropyltriethoxysilane, N- (2-aminoethyl) -3- Aminopropyltrimethoxysilane, N- (2-aminoethyl) -3-aminopropylmethyldimethoxysilane, 3-ureidopropyltrimethoxysilane, 3-ureidopropyltriethoxysilane, N-ethoxycarbonyl-3-aminopropyltrimethoxy Silane, N-ethoxycarbonyl-3-aminopropyltriethoxysilane, N-trimethoxysilylpropyltriethylenetriamine, N-triethoxysilylpropyltriethylenetriamine, 10-trimethoxysilyl-1,4,7-to Azadecane, 10-triethoxysilyl-1,4,7-triazadecane, 9-trimethoxysilyl-3,6-diazanonyl acetate, 9-triethoxysilyl-3,6-diazanonyl acetate, N-benzyl- 3-aminopropyltrimethoxysilane, N-benzyl-3-aminopropyltriethoxysilane, N-phenyl-3-aminopropyltrimethoxysilane, N-phenyl-3-aminopropyltriethoxysilane, N-bis (oxyethylene ) -3-aminopropyltrimethoxysilane, N-bis (oxyethylene) -3-aminopropyltriethoxysilane, and two or more of them may be used in combination.

  The epoxy compound is not particularly limited, but ethylene glycol diglycidyl ether, polyethylene glycol diglycidyl ether, propylene glycol diglycidyl ether, tripropylene glycol diglycidyl ether, polypropylene glycol diglycidyl ether, neopentyl glycol diglycidyl ether, 1, 6-hexanediol diglycidyl ether, glycerin diglycidyl ether, 2,2-dibromoneopentyl glycol diglycidyl ether, 6-glycidyl-2,4-hexanediol, N, N, N ′, N′-tetraglycidyl-m -Xylenediamine, 1,3-bis (N, N-diglycidylaminomethyl) cyclohexane, N, N, N ', N'-tetraglycidyl-4,4'-diaminodiphe Rumetan and the like, may be used in combination.

  The addition amount of the additive is usually 0.1 to 30% by mass and preferably 1 to 20% by mass with respect to the soluble polyimide.

  The method for applying the soluble polyimide solution is not particularly limited, and examples thereof include a dip coating method, a spin coating method, a transfer printing method, a roll coating method, an ink jet method, a spray method, and a brush coating method.

  When firing after the solution of the soluble polyimide is applied to the substrate, it is not particularly limited, but it is heated in an atmosphere such as air, an inert gas such as nitrogen, or a vacuum using a hot plate, an oven, or the like. The heating temperature is usually 40 to 220 ° C. and preferably 150 to 180 ° C. in order to reduce the residual amount of the solvent in the wettability changing layer 12. At this time, the heating temperature may be changed in order to improve the uniformity of the wettability changing layer 12.

  Next, the mechanism by which the surface free energy changes by irradiating the wettability changing layer 12 with ultraviolet rays will be described. When the wettability changing layer 12 is irradiated with ultraviolet rays having a wavelength of 300 nm or less, the ester bond and / or amide bond contained in the side chain of the soluble polyimide is cleaved to generate radicals. The generated radicals immediately react with moisture contained in the atmosphere to generate carboxyl groups, hydroxyl groups, and / or amino groups, so that the surface of the wettability changing layer 12 is hydrophilized. Thereby, the energy of the ultraviolet rays irradiated when changing the surface free energy of the wettability changing layer 12 can be reduced.

  On the other hand, the main chain of soluble polyimide is not easily cut even when irradiated with ultraviolet rays having a wavelength of 300 nm or less. For this reason, the wettability changing layer 12 can ensure insulation even when irradiated with ultraviolet rays having a wavelength of 300 nm or less.

  The wettability changing layer 12 may further include an insulating material such as polyimide, polyamideimide, epoxy resin, silsesquioxane, polyvinylphenol, polycarbonate, and fluorine resin. Moreover, the wettability change layer 12 may further contain a crosslinking agent together with polyvinyl phenol and polyvinyl alcohol. Thereby, the wettability change layer 12 excellent in insulation is obtained.

  In addition, when the film-forming property of soluble polyimide is inadequate, it is preferable to add the material excellent in film-forming property to the solution of soluble polyimide.

  The thickness of the wettability changing layer 12 is usually 30 nm to 3 μm, and preferably 50 nm to 1 μm. When the thickness of the wettability changing layer 12 is less than 30 nm, it may be difficult to form uniformly, and when it exceeds 3 μm, the shape of the surface may be deteriorated.

  The laminated structure of the present invention can be applied to a gate electrode of an organic thin film transistor and its wiring, a source / drain electrode and its wiring, and the like.

  FIG. 2 shows a bottom-gate thin film transistor as a first example of the electronic device of the present invention. In FIG. 2, the same components as those in FIG. 1 are denoted by the same reference numerals and description thereof is omitted. In the thin film transistor 20A, the gate electrode 21 is formed on the substrate 11, the insulator layer 22 having a larger volume resistivity than the wettability changing layer 12 and the wettability change on the substrate 11 on which the gate electrode 21 is formed. A gate insulating film in which the layers 12 are sequentially stacked is formed. Further, a conductor layer 13 is formed as a source / drain electrode in the ultraviolet irradiation region of the wettability changing layer 12, and a semiconductor layer 23 is formed in a channel region between the source / drain electrodes. Thereby, a source / drain electrode having a fine pattern can be easily formed.

  FIG. 3 shows a second example of the electronic device of the present invention. The thin film transistor 20B is the same as the thin film transistor 20A except that the insulator layer 22 is not formed and the wettability changing layer 12 is formed as a gate insulating film.

  FIG. 4 shows a third example of the electronic device of the present invention. The thin film transistor 20C is the same as the thin film transistor 20B except that a conductive layer 13 ′ is formed as a gate electrode in the ultraviolet irradiation region of the wettability changing layer 12 ′ instead of the gate electrode 21. The wettability changing layer 12 ′ contains soluble polyimide as with the wettability changing layer 12, but the material constituting the wettability changing layer 12 ′ may be the same as the wettability changing layer 12. , May be different. Thereby, a gate electrode and a source / drain electrode having a fine pattern can be easily formed.

  When the volume resistivity of the wettability changing layer 12 is large, the wettability changing layer 12 can also serve as a gate insulating film like the thin film transistors 20B and 20C, and the wettability changing layer 12 is formed as the gate insulating film. The On the other hand, when the volume resistivity of the wettability changing layer 12 is small, the insulator layer 22 and the wettability changing layer 12 having a larger volume resistivity than the wettability changing layer 12 are sequentially laminated as in the thin film transistor 20A. A gate insulating film is formed. When such a gate insulating film is irradiated with ultraviolet rays, the wettability changing layer 12 absorbs the ultraviolet rays, so that a decrease in the insulating properties of the insulator layer 22 can be suppressed.

  A method for forming the wettability changing layers 12 and 12 ′ and the insulator layer 22 is not particularly limited, and examples thereof include a transfer printing method, a spin coating method, and a dip coating method.

  The conductor layers 13 and 13 ′ and the gate electrode 21 can be formed by applying a coating liquid containing a conductive material and then heating or irradiating ultraviolet rays.

  The conductive material is not particularly limited, but metals such as gold, silver, copper, aluminum, and calcium; carbon materials such as carbon black, fullerenes, and carbon nanotubes; polythiophene, polyaniline, polypyrrole, polyfluorene, and derivatives thereof These organic π-conjugated polymers may be used, and two or more of them may be used in combination. Further, when forming the gate electrode and the source / drain electrodes, different conductive materials may be used.

  The coating liquid containing the conductive material is not particularly limited, but a solution in which the conductive material is dissolved in a solvent, a solution in which the precursor of the conductive material is dissolved in the solvent, or a dispersion in which the conductive material is dispersed in the solvent. Examples thereof include a liquid and a dispersion obtained by dispersing a conductive material precursor in a solvent.

  Although it does not specifically limit as a solvent, Since damage to a wettability change layer is small, water, various alcohols, etc. are mentioned. N, N-dimethylformamide, N, N-dimethylacetamide, 2-pyrrolidone, N-methyl-2-pyrrolidone, n-ethyl-2-pyrrolidone, N-vinyl-2-pyrrolidone, N-methylcaprolact Solvents such as dimethyl sulfoxide and tetramethylurea can also be used in the range where the damage of the wettability changing layer is small.

  As a coating liquid containing a conductive material, a dispersion liquid in which metal particles such as silver, gold, nickel, and copper are dispersed in an organic solvent or water, doped PANI (polyaniline), PEDOT (polyethylenedioxythiophene), PSS ( An aqueous solution of a conductive polymer doped with (polystyrenesulfonic acid) and the like.

  A method for applying a coating solution containing a conductive material is not particularly limited, and examples thereof include a spin coating method, a dip coating method, a screen printing method, an offset printing method, and an ink jet method. Among these, an inkjet method capable of ejecting small droplets is preferable because it is easily affected by the surface free energy of the wettability changing layer. When a normal head of a level used in a printer is used, the resolution of the ink jet method is 30 μm and the alignment accuracy is about ± 15 μm, but by using the difference in surface free energy in the wettability changing layer, A conductor layer having a simple pattern can be formed.

  Although it does not specifically limit as a material which comprises the insulator layer 22, Polyimide, polyamideimide, an epoxy resin, silsesquioxane, polyvinylphenol, a polycarbonate, a fluorine resin, poly (p-xylylene) etc. are mentioned.

  The semiconductor layer 23 may be either an inorganic semiconductor layer or an organic semiconductor layer, but an organic semiconductor layer is preferable because the manufacturing process of the thin film transistor can be simplified and the cost can be reduced.

  Although it does not specifically limit as a material which comprises an inorganic semiconductor layer, CdSe, CdTe, Si, etc. are mentioned.

  A method for forming the inorganic semiconductor layer is not particularly limited, and examples thereof include a method using a vacuum process such as sputtering, a sol-gel method, and the like.

  Although it does not specifically limit as a material which comprises an organic-semiconductor layer, Organic low molecules, such as a pentacene, anthracene, tetracene, phthalocyanine; Polyacetylene type conductive polymer; Poly (p-phenylene) and its derivative, Polyphenylene vinylene and its derivative Polyphenylene-based conductive polymers such as polypyrrole and derivatives thereof, polythiophene and derivatives thereof, heterocyclic conductive polymers such as polyfuran and derivatives thereof, and ionic conductive polymers such as polyaniline and derivatives thereof.

  A method for forming the organic semiconductor layer is not particularly limited, and examples thereof include a spin coating method, a spray coating method, a printing method, and an ink jet method.

  FIG. 5 shows a thin film transistor array as an example of the electronic element array of the present invention. The thin film transistor array 30 includes a plurality of thin film transistors 20C. 5A and 5B are a cross-sectional view and a top view, respectively.

  FIG. 6 shows an electrophoresis panel as an example of the image display medium of the present invention. In the electrophoresis panel 40, a transparent electrode 42 is formed on a transparent substrate 41, and an image display layer 43 including a microcapsule 43 a as an electrophoresis element and a binder 43 b is formed on the electrode 42. . At this time, the microcapsule 43a includes, for example, white titanium oxide particles and Isopar L (manufactured by Exxon Chemical Co., Ltd.) colored with oil blue. Further, the image display layer 43 and the thin film transistor array 30 as an active matrix substrate are bonded.

  The image display medium of the present invention is not limited to an electrophoretic panel, and may be a liquid crystal panel, an organic EL panel, or the like that combines an active matrix substrate and an image display element such as a liquid crystal element or an organic EL element. . The image display medium of the present invention can be used as electronic paper.

  FIG. 7 shows a pocket PC as an example of the image display device of the present invention. The pocket PC 50 uses an electrophoresis panel 40 as a flat screen, and an image is displayed by inputting image information from the input unit 51.

  In addition to this, the image display medium of the present invention can be applied to a copying machine, or can be embedded in a sheet portion, a windshield surface, or the like of a mobile traffic medium such as an automobile or an airplane.

  In addition to the image display medium, the electronic element array of the present invention can be applied to solar cells, RFID tags, and the like.

  The following examples specifically illustrate the present invention, and the present invention is not limited to the examples.

[Synthesis of Soluble Polyimide A]
Chemical formula

で表されるジアミン０．２モル及び化学式

0.2 mol of diamine represented by the formula and chemical formula

で表されるジアミン０．８モルをＮＭＰ（Ｎ−メチル−２−ピロリドン）１０ｇに溶解させた液を攪拌しながら、化学式

While stirring a solution obtained by dissolving 0.8 mol of a diamine represented by the formula (1) in 10 g of NMP (N-methyl-2-pyrrolidone), the chemical formula

で表されるテトラカルボン酸二無水物１．０モルをＮＭＰ１０ｇに溶解させた液を添加して、２５℃で１２時間開環重付加反応させて、ポリアミド酸を合成した。次に、ピリジン１．０モル及び無水酢酸１．０モルを添加して、アルゴンガス雰囲気下、１２０℃で４時間脱水閉環反応させた。得られた反応液を、攪拌しているメタノール中に投入して沈殿させた後、濾過した。次に、メタノールで洗浄した後、減圧乾燥した。得られた粉末をＮＭＰに溶解させ、攪拌しているヘキサン中に投入して沈殿させた後、濾過した。さらに、ヘキサンで洗浄した後、減圧乾燥し、化学式

A solution obtained by dissolving 1.0 mol of tetracarboxylic dianhydride represented by the formula (1) in 10 g of NMP was added and subjected to ring-opening polyaddition reaction at 25 ° C. for 12 hours to synthesize polyamic acid. Next, 1.0 mol of pyridine and 1.0 mol of acetic anhydride were added, and dehydration ring-closing reaction was performed at 120 ° C. for 4 hours in an argon gas atmosphere. The obtained reaction solution was poured into stirred methanol and precipitated, and then filtered. Next, after washing with methanol, it was dried under reduced pressure. The obtained powder was dissolved in NMP, poured into stirred hexane and precipitated, and then filtered. Furthermore, after washing with hexane, drying under reduced pressure, chemical formula

で表される可溶性ポリイミドＡを得た。

The soluble polyimide A represented by these was obtained.

[Synthesis of Soluble Polyimide B]
Chemical formula

で表されるジアミン０．２モル及び化学式

0.2 mol of diamine represented by the formula and chemical formula

で表されるジアミン０．８モルをＮＭＰ１０ｇに溶解させた液を攪拌しながら、化学式

While stirring a solution obtained by dissolving 0.8 mol of diamine represented by

で表されるテトラカルボン酸二無水物１．０モルをＮＭＰ１０ｇに溶解させた液を添加して、２５℃で１２時間開環重付加反応させて、ポリアミド酸を合成した。次に、ピリジン１．０モル及び無水酢酸１．０モルを添加して、アルゴンガスを注入しながら、１２０℃で４時間脱水閉環反応させた。得られた反応液を、攪拌しているメタノール中に投入して沈殿させた後、濾過した。次に、メタノールで洗浄した後、減圧乾燥した。得られた粉末をＮＭＰに溶解させ、攪拌しているヘキサン中に投入して沈殿させた後、濾過した。さらに、ヘキサンで洗浄した後、減圧乾燥し、化学式

A solution obtained by dissolving 1.0 mol of tetracarboxylic dianhydride represented by the formula (1) in 10 g of NMP was added and subjected to ring-opening polyaddition reaction at 25 ° C. for 12 hours to synthesize polyamic acid. Next, 1.0 mol of pyridine and 1.0 mol of acetic anhydride were added, and dehydration ring-closing reaction was performed at 120 ° C. for 4 hours while injecting argon gas. The obtained reaction solution was poured into stirred methanol and precipitated, and then filtered. Next, after washing with methanol, it was dried under reduced pressure. The obtained powder was dissolved in NMP, poured into stirred hexane and precipitated, and then filtered. Furthermore, after washing with hexane, drying under reduced pressure, chemical formula

で表される可溶性ポリイミドＢを得た。

The soluble polyimide B represented by this was obtained.

[Synthesis of Soluble Polyimide C]
Chemical formula

で表されるジアミン０．２モル及び化学式

0.2 mol of diamine represented by the formula and chemical formula

で表されるジアミン０．８モルをＮＭＰ１０ｇに溶解させた液を攪拌しながら、４，４'−（２，２−ヘキサフルオロイソプロピリデン）ジフタル酸二無水物１．０モルをＮＭＰ１０ｇに溶解させた液を添加して、２５℃で１２時間開環重付加反応させて、ポリアミド酸を合成した。次に、ピリジン１．０モル及び無水酢酸１．０モルを添加して、アルゴンガスを注入しながら、１２０℃で４時間脱水閉環反応させた。得られた反応液を、攪拌しているメタノール中に投入して沈殿させた後、濾過した。次に、メタノールで洗浄した後、減圧乾燥した。得られた粉末をＮＭＰに溶解させ、攪拌しているヘキサン中に投入して沈殿させた後、濾過した。さらに、ヘキサンで洗浄した後、減圧乾燥し、化学式

While stirring a solution obtained by dissolving 0.8 mol of diamine represented by the formula (1) in 10 g of NMP, 1.0 mol of 4,4 ′-(2,2-hexafluoroisopropylidene) diphthalic dianhydride is dissolved in 10 g of NMP. The solution was added and subjected to ring-opening polyaddition reaction at 25 ° C. for 12 hours to synthesize polyamic acid. Next, 1.0 mol of pyridine and 1.0 mol of acetic anhydride were added, and dehydration ring-closing reaction was performed at 120 ° C. for 4 hours while injecting argon gas. The obtained reaction solution was poured into stirred methanol and precipitated, and then filtered. Next, after washing with methanol, it was dried under reduced pressure. The obtained powder was dissolved in NMP, poured into stirred hexane and precipitated, and then filtered. Furthermore, after washing with hexane, drying under reduced pressure, chemical formula

で表される可溶性ポリイミドＣを得た。

The soluble polyimide C represented by this was obtained.

[Synthesis of Soluble Polyimide D]
Chemical formula

で表されるジアミン１．０モルをＮＭＰ１０ｇに溶解させた液を攪拌しながら、ピロメリット酸二無水物１．０モルをＮＭＰ１０ｇに溶解させた液を添加して、２５℃で１２時間開環重付加反応させて、ポリアミド酸を合成した。次に、ピリジン１．０モル及び無水酢酸１．０モルを添加して、２５℃で１２時間脱水閉環反応させた。得られた反応液を、攪拌しているメタノール中に投入して沈殿させた後、濾過した。次に、メタノールで洗浄した後、減圧乾燥した。得られた粉末をＮＭＰに溶解させ、攪拌しているヘキサン中に投入して沈殿させた後、濾過した。さらに、ヘキサンで洗浄した後、減圧乾燥し、化学式

While stirring a solution in which 1.0 mol of diamine represented by NMP is dissolved in 10 g of NMP, a solution in which 1.0 mol of pyromellitic dianhydride is dissolved in 10 g of NMP is added, and the ring is opened at 25 ° C. for 12 hours. A polyaddition reaction was carried out to synthesize polyamic acid. Next, 1.0 mol of pyridine and 1.0 mol of acetic anhydride were added, and a dehydration ring-closing reaction was performed at 25 ° C. for 12 hours. The obtained reaction solution was poured into stirred methanol and precipitated, and then filtered. Next, after washing with methanol, it was dried under reduced pressure. The obtained powder was dissolved in NMP, poured into stirred hexane and precipitated, and then filtered. Furthermore, after washing with hexane, drying under reduced pressure, chemical formula

で表される可溶性ポリイミドＤを得た。

The soluble polyimide D represented by these was obtained.

[Contact angle]
After applying a 5 mass% NMP solution of soluble polyimides A to D on a glass substrate 11 using a spin coat method, the wettability changes by sequentially heating at 80 ° C. and 200 ° C. using an oven. Layer 12 was formed. When the thickness of the wettability changing layer 12 was measured using a stylus method, all of them were 100 nm.

  Next, after a predetermined amount (see Table 1) of ultraviolet rays is irradiated onto the wettability changing layer 12 using an ultra-high pressure mercury lamp, a dispersion liquid in which silver nanoparticles are dispersed in an aqueous solvent (hereinafter referred to as silver nano ink). The contact angle of was measured using the drop method.

[Patternability]
After applying a 5 mass% NMP solution of soluble polyimides A to D on a glass substrate 11 using a spin coat method, the wettability changes by sequentially heating at 80 ° C. and 200 ° C. using an oven. Layer 12 was formed. When the thickness of the wettability changing layer 12 was measured using a stylus method, all of them were 100 nm.

  Next, the wettability changing layer 12 was irradiated with a predetermined amount (see Table 1) of ultraviolet rays through a photomask having a line shape at intervals of 5 μm using an ultrahigh pressure mercury lamp. Furthermore, after apply | coating silver nanoink to the ultraviolet irradiation area | region 12a using the inkjet method, the conductor layer 13 was formed by baking at 200 degreeC using oven, and the laminated structure 10 was obtained. (See FIG. 1).

  Next, the conductor layer 13 was observed using metallographic observation, and the patterning property was evaluated. In addition, the case where the line shape of 5 μm intervals was not formed was judged as “x”, the case where some were formed as “Δ”, the case where almost all were formed as “◯”, and the case where all were formed as “◎”.

[Evaluation results]
Table 1 shows the contact angle measurement results and the patterning evaluation results.

表１より、パターニング性は、接触角の変化と相関していることがわかる。即ち、可溶性ポリイミドＡ〜Ｃを含む濡れ性変化層１２は、紫外線の照射量が１５Ｊ／ｃｍ^２以下であっても、紫外線照射領域１２ａと紫外線非照射領域１２ｂの表面自由エネルギーの差が十分に大きいため、５μｍ間隔のライン形状の導電体層１３が形成される。一方、可溶性ポリイミドＤを含む濡れ性変化層１２は、紫外線の照射量が１５Ｊ／ｃｍ^２以下であると、紫外線照射領域１２ａと紫外線非照射領域１２ｂの表面自由エネルギーの差が不十分であるため、５μｍ間隔のライン形状の導電体層１３が形成されない。

From Table 1, it can be seen that the patterning property correlates with the change in the contact angle. That is, the wettability changing layer 12 containing the soluble polyimides A to C has a sufficient difference in surface free energy between the ultraviolet irradiation region 12a and the ultraviolet non-irradiation region 12b even when the ultraviolet irradiation amount is 15 J / cm ² or less. Because of the large size, the line-shaped conductor layer 13 having an interval of 5 μm is formed. On the other hand, if the wettability changing layer 12 containing the soluble polyimide D has an ultraviolet irradiation amount of 15 J / cm ² or less, the difference in surface free energy between the ultraviolet irradiation region 12a and the ultraviolet non-irradiation region 12b is insufficient. The line-shaped conductor layer 13 with an interval of 5 μm is not formed.

[Fabrication of Thin Film Transistor 1]
A gate electrode 21 having a thickness of 50 nm was formed on a glass substrate 11 by vapor-depositing aluminum under vacuum using a metal mask. Next, an insulator layer 22 having a thickness of 300 nm was formed on the substrate 11 on which the gate electrode 21 was formed by depositing parylene under vacuum. Further, a 5 mass% NMP solution of soluble polyimides A to C is applied onto the substrate 11 on which the insulator layer 22 is formed by using a spin coat method, and then sequentially at 80 ° C. and 200 ° C. using an oven. By heating, the wettability changing layer 12 having a thickness of 100 to 150 nm was formed. Next, an ultraviolet irradiation region was formed in the wettability changing layer 12 by irradiating ultraviolet rays of 5 J / cm ² through a photomask using an ultrahigh pressure mercury lamp. Furthermore, after applying silver nanoink to the ultraviolet irradiation region of the wettability changing layer 12 using an inkjet method, the conductive layer 13 (channel) having a thickness of 60 nm is heated by heating at 200 ° C. using an oven. A source / drain electrode having a length of 5 μm) was formed. Next, the chemical formula is applied to the channel region between the source and drain electrodes using the inkjet method.

で表される化合物のキシレン溶液を塗布した後、オーブンを用いて、１２０℃で加熱することにより、厚さが４０ｎｍの半導体層２３を形成し、薄膜トランジスタ２０Ａを得た（図２参照）。

After the application of the xylene solution of the compound represented by the formula (1), the semiconductor layer 23 having a thickness of 40 nm was formed by heating at 120 ° C. using an oven to obtain the thin film transistor 20A (see FIG. 2).

  Table 2 shows evaluation results of transistor characteristics of the obtained thin film transistor 20A.

表２より、可溶性ポリイミドＡ又はＢを用いて作製した薄膜トランジスタ２０Ａは、電界効果移動度が大きいことに加え、ゲートリーク電流及び表面リーク電流が小さく、オンオフ比が大きいことがわかる。これは、テトラカルボン酸二無水物由来の構成単位の絶縁性が大きいことに加え、濡れ性変化層１２の表面平滑性が大きいためであると考えられる。このとき、可溶性ポリイミドＡを用いた場合、可溶性ポリイミドＢを用いる場合よりも、薄膜トランジスタ２０Ｃのオンオフ比が大きく、紫外線による濡れ性変化層１２の絶縁性の低下が抑制されていることがわかる。これは、可溶性ポリイミドＡが、可溶性ポリイミドＢよりも、テトラカルボン酸二無水物由来の構成単位の絶縁性が大きいためであると考えられる。

From Table 2, it can be seen that the thin film transistor 20A manufactured using the soluble polyimide A or B has high field effect mobility, low gate leakage current and surface leakage current, and high on / off ratio. This is presumably because the surface smoothness of the wettability changing layer 12 is large in addition to the large insulating properties of the structural units derived from tetracarboxylic dianhydride. At this time, it can be seen that when soluble polyimide A is used, the on-off ratio of the thin film transistor 20C is larger than when soluble polyimide B is used, and the decrease in insulation of the wettability changing layer 12 due to ultraviolet rays is suppressed. This is presumably because soluble polyimide A has a greater insulating property of the structural unit derived from tetracarboxylic dianhydride than soluble polyimide B.

  This value was not inferior to that of the thin film transistor manufactured in the same manner as the thin film transistor 20A except that gold was deposited under vacuum using a metal mask when forming the source / drain electrodes.

  On the other hand, when soluble polyimide C is used, the field effect mobility is small, the surface leakage current is large, and the on / off ratio is small. The surface leakage current is considered to be caused by poor flatness and insulation of the wettability changing layer 12.

[Production of Thin Film Transistor 2]
Using a spin coat method, a 5 mass% cyclohexanone solution of soluble polyimides A and B is applied on a film substrate 11 and then heated at 150 ° C. using an oven to obtain a thickness of 90 nm. The property change layer 12 ′ was formed. Next, an ultra-high pressure mercury lamp was used to irradiate ² J / cm ² of ultraviolet rays through a photomask to form an ultraviolet irradiation region in the wettability changing layer 12 ′. Furthermore, after applying silver nanoink to the ultraviolet irradiation region of the wettability changing layer 12 ′ using an inkjet method, the conductive layer 13 ′ having a thickness of 50 nm is heated at 170 ° C. using an oven. (Gate electrode) was formed. Next, a 5 mass% cyclohexanone solution of soluble polyimides A and B is applied on the substrate 11 on which the wettability changing layer 12 ′ and the conductor layer 13 ′ are formed by using a spin coating method, and then an oven is used. Then, the wettability changing layer 12 having a thickness of 300 nm was formed by heating at 170 ° C. Further, an ultraviolet irradiation region was formed in the wettability changing layer 12 by irradiating with ultraviolet rays of 5 J / cm ² through a photomask using an ultrahigh pressure mercury lamp. Next, after applying silver nano ink to the ultraviolet irradiation region of the wettability changing layer 12 using an ink jet method, the conductive layer 13 (60 nm in thickness) is heated by using an oven at 170 ° C. Source / drain electrodes having a channel length of 5 μm) were formed. Furthermore, the chemical formula is applied to the channel region between the source and drain electrodes using the inkjet method.

で表される化合物のキシレン溶液を塗布した後、オーブンを用いて、１２０℃で加熱することにより、厚さが４０ｎｍの半導体層２３を形成し、薄膜トランジスタ２０Ｃを得た（図４参照）。

After applying a xylene solution of the compound represented by formula (1), the semiconductor layer 23 having a thickness of 40 nm was formed by heating at 120 ° C. using an oven to obtain a thin film transistor 20C (see FIG. 4).

  Table 3 shows the evaluation results of the transistor characteristics of the obtained thin film transistor 20C.

表３より、可溶性ポリイミドＡ又はＢを用いて作製した薄膜トランジスタ２０Ｃは、電界効果移動度が大きいことに加え、ゲートリーク電流及び表面リーク電流が小さく、オンオフ比が大きいことがわかる。これは、テトラカルボン酸二無水物由来の構成単位の絶縁性が大きいことに加え、濡れ性変化層１２の表面平滑性が大きいためであると考えられる。このとき、可溶性ポリイミドＡを用いた場合、可溶性ポリイミドＢを用いる場合よりも、薄膜トランジスタ２０Ｃのオンオフ比が大きく、紫外線による濡れ性変化層１２の絶縁性の低下が抑制されていることがわかる。これは、可溶性ポリイミドＡが、可溶性ポリイミドＢよりも、テトラカルボン酸二無水物由来の構成単位の絶縁性が大きいためであると考えられる。

From Table 3, it can be seen that the thin film transistor 20C manufactured using the soluble polyimide A or B has high field effect mobility, low gate leakage current and surface leakage current, and high on / off ratio. This is presumably because the surface smoothness of the wettability changing layer 12 is large in addition to the large insulating properties of the structural units derived from tetracarboxylic dianhydride. At this time, it can be seen that when soluble polyimide A is used, the on-off ratio of the thin film transistor 20C is larger than when soluble polyimide B is used, and the decrease in insulation of the wettability changing layer 12 due to ultraviolet rays is suppressed. This is presumably because soluble polyimide A has a greater insulating property of the structural unit derived from tetracarboxylic dianhydride than soluble polyimide B.

[Preparation of electrophoresis panel]
Using soluble polyimide A, a thin film transistor array 30 (see FIG. 5) having 32 × 32 (element pitch 500 μm) thin film transistors 20C in a two-dimensional array was produced in the same manner as the thin film transistor 20C. Note that a microcontact printing method was used when the semiconductor layer 23 was formed in an island shape.

When the transistor characteristics of the obtained thin film transistor array 30 were evaluated, the average value of the field effect mobility was 1.1 × 10 ⁻³ cm ² / V · sec, and the average value of the on / off ratio was 6 digits.

  Next, an electrophoresis panel 40 (see FIG. 6) was manufactured using the thin film transistor array 30. Specifically, a coating liquid obtained by mixing an aqueous solution of polyvinyl alcohol 43b with a microcapsule 43a enclosing titanium oxide particles and oil blue-colored isopar and a transparent transparent ITO film formed on a polycarbonate transparent substrate 41 is used. An image display layer 43 composed of microcapsules 43a and polyvinyl alcohol 43b was formed by coating on the electrode. Further, the image display layer 43 and the thin film transistor array 30 were bonded so that the substrate 11 and the transparent substrate 41 were the outermost surfaces, whereby the electrophoresis panel 40 was obtained.

  The scanning signal driver IC is connected to the bus line connected to the gate electrode 21 of the electrophoresis panel 40, the data signal driver IC is connected to the bus line connected to the source electrode, and the screen is switched every 0.5 seconds. As a result, a good still image could be displayed.

DESCRIPTION OF SYMBOLS 10 Laminated structure 11 Substrate 12, 12 'Wetting property change layer 12a Ultraviolet irradiation area | region 12b Ultraviolet non-irradiation area | region 13, 13' Conductor layer 20A, 20B, 20C Thin-film transistor 21 Gate electrode 22 Insulator layer 23 Semiconductor layer 30 Thin-film transistor array 40 Electrophoresis panel 50 Pocket PC

JP 2008-227294 A

Claims (10)

A wettability changing layer containing a material whose surface free energy is changed by irradiating ultraviolet rays is formed on the substrate, and a conductor layer is formed on a region of the wettability changing layer irradiated with the ultraviolet rays. to have a laminated structure are,
The material whose surface free energy is changed by irradiating the ultraviolet ray is a general formula

(Wherein, _{n 1} and _{n 2} are the degree of polymerization, the ratio of _{n 2} to the sum of _{n 1} and _{n 2} is less than 1% to 30%.)
Soluble polyimide or general formula organic solvent in you express

(Wherein, _{n 1} and _{n 2} are the degree of polymerization, the ratio of _{n 2} to the sum of _{n 1} and _{n 2} is less than 1% to 30%.)
A laminate structure characterized by being a polyimide soluble in an organic solvent represented by the formula: An electronic device comprising the laminated structure according to claim 1 . Electronic device according to claim 2, on the substrate, wherein the semiconductor layer and the insulator layer is further formed. The electronic device according to claim 3 , wherein the semiconductor layer includes an organic semiconductor material. Wherein on the insulating layer, an electronic device according to claim 3 or 4, characterized in that the laminated structure is formed. Electronic device according to any one of claims 3 to 5 wherein the wettability variable layer is characterized in that also serves as the insulator layer. Electronic device according to any one of claims 3 to 6, characterized in that a plurality of the laminated structure. Electronic element array and having a plurality of electronic devices according to any one of claims 2 to 7. An image display medium comprising the electronic element array according to claim 8 . An image display device comprising the image display medium according to claim 9 .

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