JP2007103221A - Transparent conductive film and electroluminescent element formed by using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a transparent conductive film hardly generating flatness defects such as curl and warp on a display body even if it is thin. <P>SOLUTION: On the transparent conductive film formed by laminating a transparent conductive layer (B) on a biaxially oriented polyester film (A), a difference between a maximum and a minimum values of a plane orientation coefficient of the biaxially oriented polyester film (A) in a range of 50 cm square defined in this text is 0.007 or less, and an average value of the plane orientation coefficient is 0.11 to 0.15. The electroluminescent element is constituted by using the above transparent conductive film. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an excellent transparent conductive film which is thin and has no poor planarity such as curling and warping.

A transparent display requires a transparent electrode. For example, in an electroluminescence element, a light emitting layer, a dielectric layer, an insulator layer, and a back electrode (metal foil or the like) are sequentially formed on a transparent conductive film in which a transparent conductive layer is laminated on a transparent film ( Patent Document 1) or a thin electroluminescent element in which a layer coated with a conductive resin layer is formed as the back electrode has been proposed (Patent Document 2).
JP-A-1-81112 JP-A-5-347186

  In recent years, with the demand for further thinning of display devices and the like, the transparent conductive film has also been required to be thinner. However, when each layer necessary as a display element such as a light emitting layer, a dielectric layer, and an insulator layer having the above-described electroluminescence element configuration is laminated on a thin transparent conductive film, the transparent conductive film is included. It has been found that the phenomenon that the display body curls into various shapes occurs, which causes warping and poor flatness.

  In view of the background of the prior art, the present invention is intended to provide a transparent conductive film that is less likely to cause flatness defects such as curling and warping on a display body even if it is thin.

  The present invention employs the following means in order to solve such problems. That is, the transparent conductive film of the present invention is a transparent conductive film in which a transparent conductive layer (B) is laminated on a biaxially stretched polyester film (A), and the biaxially stretched polyester film (A) is 50 cm square. The difference between the maximum value and the minimum value of the plane orientation coefficient defined in the text in the range is 0.007 or less, and the average of the plane orientation coefficients is 0.11 to 0.15 It is.

  Moreover, the electroluminescent element of this invention is comprised using this transparent conductive film, It is characterized by the above-mentioned.

  According to the present invention, it is possible to provide a transparent conductive film that is thinner and is less prone to poor flatness such as curling and warping. Therefore, for example, a transparent electrode for a flexible display using liquid crystal, electroluminescence, or the like, or A transparent electrode of an electroluminescence element used for a backlight for a mobile phone or an advertisement can be provided.

  The present invention has intensively studied the above-mentioned problem, that is, a transparent conductive film that is difficult to cause flatness defects such as curling and warping even if it is thin, and the variation and average of the plane coefficient are controlled within a specific range. In other words, when a transparent conductive layer was laminated on a biaxially stretched polyester film having specific planar characteristics, it was found that a transparent conductive film that can solve such problems at once can be provided. is there.

  That is, when the film is thick, the display body does not curl, warp, or have poor flatness. From this, it is conceivable to select a film having a high rigidity. However, as the film thickness decreases, the rigidity decreases in inverse proportion to the cube of the film thickness, which makes it difficult to solve the problem. Yes. By using a biaxially stretched polyester film having low rigidity and having the above-mentioned specific planar characteristics, the present invention can produce a transparent conductive film that can be made thinner and less likely to curl, warp and have poor planarity. Is found.

  The polyester constituting the biaxially stretched polyester film used in the transparent conductive film of the present invention is a general term for polymers having an ester bond in the main chain, and usually a polycondensation of a dicarboxylic acid component and a glycol component. It can be obtained by reacting. Here, examples of the dicarboxylic acid component include fragrances such as terephthalic acid, 2,6-naphthalenedicarboxylic acid, isophthalic acid, diphenyldicarboxylic acid, diphenylsulfonedicarboxylic acid, diphenoxyethanedicarboxylic acid, 5-sodiumsulfonedicarboxylic acid, and phthalic acid. Aliphatic dicarboxylic acids, oxalic acid, succinic acid, adipic acid, sebacic acid, dimer acid, maleic acid, fumaric acid and other aliphatic dicarboxylic acids, cyclohexanedicarboxylic acid and other alicyclic dicarboxylic acids, and paraoxybenzoic acid and other oxycarboxylic acids And so on. Examples of the glycol component include aliphatic glycols such as ethylene glycol, propanediol, butanediol, pentanediol, hexanediol, and neopentylglycol, polyoxyalkylene glycols such as diethylene glycol, polyethylene glycol, and polypropylene glycol, and cyclohexanedimethanol. And aromatic glycols such as bisphenol A and bisphenol S.

  The polyester of the biaxially stretched polyester film (A) used for the transparent conductive film of the present invention is not particularly limited, but the ethylene terephthalate unit and / or the ethylene 2,6-naphthalate unit is 95 mol% of the constituent components. It is preferable to contain above. 97 mol% or more is more preferable.

  The polyester of the biaxially stretched polyester film (A) used for the transparent conductive film of the present invention preferably has a melting point of 246 to 280 ° C. from the viewpoint of heat resistance. More preferably, it is 250-275 degreeC.

  The production method of the biaxially stretched polyester film (A) in the present invention is not particularly limited. For example, after drying the polyester as necessary, it is supplied to a known melt extruder and melted to form a sheet from a slit die. Or it extrudes in a tube shape, and it adheres to a casting drum by systems, such as an electrostatic application, and solidifies by cooling, and an unstretched sheet is obtained. As a film forming method, there are a tubular method, a tenter method, etc., but in terms of film quality, a tenter method is preferable, and the film is stretched in the longitudinal direction and then stretched in the width direction, or stretched in the width direction and then stretched in the longitudinal direction. A sequential biaxial stretching method of stretching and a simultaneous biaxial stretching method of stretching the longitudinal direction and the width direction almost simultaneously are desirable.

  In the biaxially stretched polyester film (A) used for the transparent conductive film of the present invention, the difference between the maximum value and the minimum value of the plane orientation coefficient in the 50 cm square range (hereinafter referred to as variation) is 0.007 or less. It is necessary. Here, the plane orientation coefficient of the film is nMD as the longitudinal refractive index of the film, nTD as the refractive index in the width direction of the film, and nZD as the refractive index in the thickness direction of the film. nMD + nTD) / 2−nZD.

  Furthermore, the variation in the plane orientation coefficient is preferably 0.005 or less, and more preferably 0.003 or less, because it is possible to more effectively prevent poor planarity.

  The refractive index and the plane orientation coefficient (fn) are measured by the following means. That is, using a sodium D line (wavelength 589 nm) as a light source and methylene iodide as a mounting liquid, the refractive index in the longitudinal direction, the width direction, and the thickness direction (respectively nX, nY, and nZ) was obtained with an Abbe refractometer. The plane orientation coefficient fn is obtained by calculating fn = (nX + nY) / 2−nZ.

  Specifically, the maximum value and the minimum value of the plane orientation coefficient in the range of 50 cm square of the film are obtained by cutting the film 50 cm square into a 10 cm square and cutting it into a grid pattern with 25 samples The surface orientation coefficient was measured and calculated by the above method by cutting out the longitudinal direction 2 cm and the width direction 1 cm from the center of the 25 samples, and the variation which is the difference between the maximum value and the minimum value of the surface orientation coefficient was obtained. is there.

  The measurement was performed three times with the position in the width direction being constant for the same film, and the average of the difference between the maximum value and the minimum value was obtained to determine the variation in the plane orientation coefficient. In the present invention, the measurement surface of the sample is obtained by measuring the plane orientation coefficient of the film surface opposite to the surface brought into close contact with the casting drum during film formation.

  In calculating and measuring the absolute value of the difference between the plane orientation coefficients of both sides of the film, 10 sample pieces of 2 cm square were taken from any place on the film, the thickness was measured with a dial gauge, and the refractive index was measured. The measurement was performed on both sides of the film.

  The method of setting the variation in the plane orientation coefficient within such a range to 0.007 or less is not particularly limited, but is a method for suppressing driving spots of a motor used for film formation, a melt-extruded polymer casting drum For example, a method for suppressing the spots at the time of adhesion to the film and the spots at the time of stretching. For example, as a method for suppressing unevenness at the time of casting and obtaining a uniform unstretched sheet, a method using a tape-like electrode as an electrode when the polymer is brought into close contact with the drum by electrostatic application is preferable. Compared to the wire electrode that has been used conventionally, the tape electrode concentrates the electric charge at the contact point between the drum and the film, and is effective in suppressing the plaque, and the occurrence of the plaque due to the flickering of the electrode itself From the viewpoint of suppressing the above, a tape electrode is preferable.

  On the other hand, as a method for suppressing the occurrence of spots during stretching, stretching conditions and stretching methods, more specifically, when a roll is used for stretching, the roundness of the roll, the uniformity of the roll surface, and the temperature uniformity of the film And the like. Among these methods, a method of stretching in the air between rolls in which the film is not in contact with the heating roll is preferable, and it is preferable to suppress fluttering of the film when stretching in the air. Further, as a method for uniformizing the temperature of the film, a method of sufficiently heating in the preheating section before stretching, and a method of preheating at a temperature higher than the stretching temperature are preferable. Specifically, when using a preheating roll, the same temperature is used. It is preferable to heat the film using at least two set rolls.

  Furthermore, the biaxially stretched polyester film (A) used for the transparent conductive film of the present invention needs to have an average of the plane orientation coefficients of 0.11 to 0.15. When the average of the plane orientation coefficient is less than 0.11, the variation becomes large, causing problems in flatness such as warpage in the drying process, and when the average of the plane orientation coefficient exceeds 0.15, The flatness is inferior. The average of such plane orientation coefficients is more preferably in the range of 0.127 to 0.145. A method for setting the average of the plane orientation coefficients within such a range is not particularly limited, but can be achieved by, for example, setting stretching conditions and heat treatment conditions in an appropriate range. From the viewpoint of productivity, it is preferable to stretch the film at a high ratio by increasing the stretching temperature. However, stretching at a high temperature tends to cause variation in stretching tension, which is not preferable from the viewpoint of alignment spots. Thus, when a roll is used for stretching, silicone and ceramic are preferable as the roll surface, and it is particularly preferable to use a non-adhesive silicone made of roll surface material. Furthermore, when a means for simultaneous biaxial stretching is adopted, the stretching tension tends to be uniform, which is preferable from the viewpoint of alignment spots. Moreover, you may extend | stretch by raising a film temperature uniformly to high temperature in a short time using a radiant heat.

  The biaxially stretched polyester film (A) used for the transparent conductive film of the present invention has a dimensional change rate of −0 in the longitudinal direction of the film before and after the heating and the width direction perpendicular thereto when heated at 150 ° C. for 30 minutes. It is more preferable that the content is in the range of 0.5 to + 0.5% because it is possible to prevent poor planarity in the step of drying each stack constituting the display element.

  Here, the rate of dimensional change before and after heating of the polyester film is determined by cutting the film into a square of 150 mm in the longitudinal direction and 150 mm in the direction perpendicular to the film, and then using an iron pen in the longitudinal direction and the direction perpendicular to the center of the cut film. In each case, a mark line of 100 mm is provided. Read the mark before heat treatment with calipers, set the length before treatment (L0), heat the film for 30 minutes in an oven at 150 ° C., cool it for 30 minutes or more at room temperature, The length is read with calipers, and the dimensional change rate is calculated by the following equation as the post-processing length (L).

Dimensional change rate before and after heating (%) = [(L−L0) / L0] * 100
In the biaxially stretched polyester film (A) used for the transparent conductive film of the present invention, the relationship between the film thickness t (unit: μm) and the absolute value Δf of the difference between the plane orientation coefficients of both sides of the film is expressed by the following formula (1). Satisfaction is preferable in terms of preventing poor planarity in the drying process.

0.001 ≦ Δf · t ≦ 0.700 (1)
If Δf · t exceeds 0.700, the degree of deformation may greatly differ between the front and back of the film in the drying step, which is not preferable. On the other hand, when Δf · t is less than 0.001, the flatness is deteriorated, which is not preferable. In order to hold the electroluminescent coating layer, the film thickness t is
10-250 micrometers is preferable. The effect of the present invention is remarkably exhibited in a thin film having a film thickness of 10 μm to 130 μm.

The biaxially stretched polyester film (A) used for the transparent conductive film of the present invention has a carbonyl relaxation time (τ1) and a phenyl group at a relaxation time T1ρ measured by solid high-resolution nuclear magnetic resonance spectroscopy (NMR). It is preferable from the viewpoint of planarity in the drying step that the relationship between the relaxation times (τ2) of the quaternary carbon satisfies the following formula (2).
1.8 ≦ τ1 / τ2 ≦ 50 (2)
If (τ1 / τ2) is within such a range, a crystalline and amorphous intermediate phase in which the mobility in the polyester molecular chain is suppressed is formed, and the structure is maintained even after the drying step. As a result, it is possible to exhibit excellent impact resistance. Therefore, if (τ1 / τ2) is less than 1.8, the molecular chain mobility is weakly suppressed, the flatness may be deteriorated, and the flatness after molding may be inferior. On the other hand, if (τ1 / τ2) exceeds 50, the mobility may be suppressed too much and the flatness may be deteriorated.

  The method of setting the relationship between τ1 and τ2 within such a range is not particularly limited, but is achieved by optimizing the intrinsic viscosity of the polyester, the catalyst, the amount of diethylene glycol, the stretching conditions and the heat treatment conditions during film production, and the like. be able to.

  About the manufacturing method of these biaxially stretched polyester films (A) preferable to use for the transparent conductive film of this invention, it is disclosed by Unexamined-Japanese-Patent No. 2000-289024, Unexamined-Japanese-Patent No. 2001-347565, and Unexamined-Japanese-Patent No. 2002-103443. Means can be employed.

  In order to increase the adhesion between the biaxially stretched polyester film (A) and the transparent conductive layer (B), the film / sheet is coated with the adhesive resin after the film / sheet, or the film / sheet, Alternatively, it is preferable to perform a surface treatment such as a discharge treatment.

  Here, the film means a film having a thickness of 1 μm or more and 2 mm or less.

  As the transparent conductive layer (B) laminated on the biaxially stretched polyester film (A), it is preferable to have conductivity and transparency when forming a thin film, for example, gold, silver, platinum, palladium, rhodium. Metal-based transparent conductivity such as tin oxide, indium oxide, antimony oxide, titanium oxide, zinc oxide, zirconium oxide, or conductive metal oxide such as indium oxide-tin oxide and tin oxide-antimony oxide It is preferable because the conductive thin film exhibits high conductivity while maintaining transparency. Among them, a conductive metal oxide having the same conductivity but high transparency is more preferable. Particularly preferred are indium oxide, tin oxide, zinc oxide, or two or more of these compounds. These metal conductive thin films can be formed by a vacuum deposition method, a sputtering method, an ion plating method or the like.

  These transparent conductive layers (B) may be a single layer or may be a multilayer of two or more layers. The thickness of the transparent conductive layer (B) is not particularly limited, but the surface electrical resistance value is preferably 1Ω / □ to 1000Ω / □, more preferably 30Ω / □ to 1000Ω / □. The total light transmittance in the visible light region of the transparent conductive layer (B) is 50% or more, preferably 70% or more.

  Regarding the surface electrical resistance, it is better to lower the surface electrical resistance value of the transparent conductive film in order to increase the light emission luminance of the electroluminescence element. However, the power consumption increases at 1Ω / □ or less, which is uneconomical. In view of this balance, it is preferably 30Ω / □ or more and 1000Ω / □ or less. The higher the total light transmittance, the more light emitted from the electroluminescence light can be transmitted. Therefore, the light emission luminance of the electroluminescence element is preferably increased. However, if the total light transmittance is 50% or more, there is no practical problem, but 70% or more. If it exists, it is more preferable at the point which light emission luminance becomes high.

  The surface resistance value here is measured by placing a measurement electrode on the dielectric layer by a four-probe method based on JIS R1637, and the total light transmittance is measured based on JIS K7105. It is.

  As the transparent conductive layer (B) of the transparent conductive film of the present invention, a conductive polymer can also be used. Examples of the conductive polymer include polypyrrole, polythiophene, polyfuran, polyselenophene, polyaniline, polyparaphenylene, polyfluorene, and derivatives thereof, and copolymers thereof in terms of transparency, conductivity, and flexibility. Any one kind or a mixture of two or more kinds of conductive polymers selected from the above can be used. Among them, it is selected from polythiophene, polyalkylfluorene, polyfluorene, polyparaphenylene, polyparaphenylene vinylene derivatives and copolymers thereof that are soluble or dispersible in water or other solvents by introducing side chains. More preferably, at least one kind of conductive polymer is excellent in transparency and conductivity, can be coated on a film / sheet, and can uniformly form a conductive polymer film having an appropriate thickness. used. In particular, conductive polymers containing polydioxythiophene, especially conductive polymers made of polyethylenedioxythiophene (PEDOT) and polystyrene sulfonic acid (PSS), can be easily dissolved or dispersed in water or other solvents. Further, it is most preferably used because it can be coated on a polymer film and a film having particularly high transparency and conductivity can be formed.

  A method for preparing a resin liquid in which a conductive polymer composed of polyethylenedioxythiophene and polystyrenesulfonic acid is dissolved or dispersed in water or other solvent is disclosed in JP-A-7-90060, Japanese Patent No. 3210211, or International Publication. The means proposed in the 02/067273 pamphlet can be employed.

  Addition of particles such as polystyrene particles and acrylic resin particles to the conductive polymer increases the slipperiness, so that it is easy to stack the cut film / sheet when cutting the film / sheet to the display screen size. The features of. Moreover, the addition of the resin increases the strength of the transparent conductive layer (B) and improves the stability of quality such as rubbing and scratch durability.

  The method of laminating the conductive polymer on the biaxially stretched polyester film (A) includes an electrolytic polymerization method, a vapor deposition method, a coating method (coating method), and the like, which can be appropriately selected depending on the application and the conductive organic material, and is particularly limited. It is not a thing. However, the conductive polymer that is soluble in water or other solvents is laminated by the coating method because it can be laminated uniformly with a specified thickness on a wide substrate such as a film / sheet and a long length. More preferred. The coating method is not particularly limited, and an appropriate method can be selected and used according to the application.

  The thickness of the transparent conductive layer (B) using the conductive polymer differs depending on the type of the conductive polymer, and should be appropriately determined according to the surface resistance value and the light transmittance. Specifically, the thickness is about 400 nm to 5 μm. The more preferable thickness is from 500 nm to 2 μm in terms of surface resistance and light transmittance. If it is less than 400 nm, the surface resistance value becomes high, and if it exceeds 5 μm, the light transmittance decreases due to light absorption of the conductive polymer.

  Hereinafter, the present invention will be described by way of examples. The characteristic values in the examples are evaluated by the following methods. The evaluation was carried out in a room controlled at a room temperature of 20 to 25 ° C. and a relative humidity of 40 to 65%.

(1) The rate of dimensional change before and after heating of the polyester film was cut in a 150 mm square in the direction perpendicular to the longitudinal direction of 150 mm, and 100 mm each with an iron pen in the longitudinal direction and the direction perpendicular to the center of the cut out film. A marked line was set. Read the marked line before heat treatment with calipers and set it to the length before treatment (L0). After the film has been heated in an oven at 150 ° C. for 30 minutes and then cooled at room temperature for 30 minutes or more, the length of the marked line provided before treatment is caliper. The length after reading processing (L). The dimensional change rate was calculated by the following formula.
Dimensional change rate before and after heating (%) = [(L−L0) / L0] * 100.

  (2) Melting | fusing point of polyester Polyester was crystallized, it measured with the temperature increase rate of 10 degree-C / min with the differential scanning calorimeter (DSC7 type | mold by Perkin-Elmer Co., Ltd.), and the peak temperature of melting was made into melting | fusing point.

(3) Refractive index and plane orientation coefficient (fn) are sodium D line (wavelength 589 nm) as a light source, methylene iodide is used as a mounting solution, and the refractive index in the longitudinal direction, width direction, and thickness direction is measured with an Abbe refractometer. (Respectively nX, nY, nZ) were determined. The plane orientation coefficient fn is fn = (nX + nY) / 2−nZ
Was calculated.

  The maximum value and the minimum value of the plane orientation coefficient in the range of 50 cm square of the film are obtained by cutting the film 50 cm square into a 10 cm square in a grid pattern by making the measurement surface of the film constant, For 25 samples, the plane orientation coefficient was measured and calculated by the above-described method, and the variation, which is the difference between the maximum value and the minimum value of the plane orientation coefficient, was obtained.

  The measurement was performed three times with the position in the width direction being constant for the same film, and the average of the difference between the maximum value and the minimum value was obtained to determine the variation in the plane orientation coefficient. In this example, the measurement surface of the sample was measured for the plane orientation coefficient of the film surface opposite to the surface brought into close contact with the casting drum during film formation.

  In calculating and measuring the absolute value of the difference between the plane orientation coefficients of both sides of the film, 10 sample pieces of 2 cm square were taken from any place on the film, the thickness was measured with a dial gauge, and the refractive index was measured. Was measured on both sides of the film.

  (4) The surface resistance value was measured by placing a measurement electrode on the dielectric layer by a four-probe method based on JIS R1637.

  (5) Total light transmittance, b * value: measured based on JIS K7105.

(6) The warpage and flatness of the electroluminescence element were determined by visual observation by leaving the back electrode side facing down on a standard stone board. Judgment criteria were as follows, and a “good” judgment was accepted.
○ Judgment: No warping and no undulation on the plane ▲ Judgment: No warping but a bumpy undulation on the plane x Judgment: State with warping [Examples 1 to 3]
In Examples 1 to 3, the polyethylene terephthalate was sufficiently vacuum-dried, and then melt-extruded at 280 ° C. and adhered to the casting drum to obtain an unstretched sheet. At that time, a tape-like electrode was used as the electrostatic application electrode. Next, the biaxially stretched polyester film was obtained by successively biaxially stretching the unstretched sheet. At that time, the stretching conditions were such that the preheating temperature before stretching in the longitudinal direction was 115 ° C. (5 seconds), the stretching temperature was 113 ° C., and the magnification was 3.1 times while the film was in the air at a stretching speed of 65000% / min. Once the film temperature was cooled to 35 ° C., a pre-stretching preheating temperature of 95 ° C. (5 seconds) was set in the orthogonal direction, and stretching in the width direction was performed at a stretching temperature of 120 ° C. and a magnification of 3.2 times. After stretching, heat treatment was performed at a temperature of 190 ° C. (6 seconds). The thickness of the film was adjusted by changing the melt extrusion amount and changing the thickness of the unstretched sheet. The film obtained by this method was conveyed so as to be heated in a hot air oven heated to 200 ° C. for 1 minute to obtain a polymer film as a base material (A).

An ITO thin film (transparent conductive layer (B)) was formed on the substrate (A) using a roll-up DC pulsing magnetron sputtering apparatus so that the surface resistance value was 400Ω / □. The sputtering conditions were an ITO target (indium oxide (90 wt%) and tin oxide (10 wt%) sintered target (sintering density 99% or more)), and a sputtering apparatus up to a vacuum degree of 4 × 10 ⁻³ Pa. After evacuating the inside, an Ar / O ₂ mixed gas containing 3.5 mol% oxygen was introduced to make the degree of vacuum 4 × 10 ⁻² Pa, and then sputtered at a substrate speed of 3 m / min. Table 1 shows the evaluation results of the obtained transparent conductive film.

  The obtained transparent conductive film was cut into a 50 cm square, and an inorganic electroluminescence layer was formed by the following method in order to produce 25 electroluminescence elements in an arbitrary arrangement.

  First, 30 parts of a fluororesin binder, 40 parts of an organic solvent methyl ethyl ketone and 30 parts of a fluorescent phosphor are mixed on the transparent conductive layer (B) of the transparent conductive film, screen-printed, and heated at 120 ° C. for 3 minutes with a far-infrared heater. The phosphor layer (C) was formed by drying.

  Next, 30 parts of fluororesin, 40 parts of organic solvent methyl ethyl ketone and 30 parts of barium titanate are mixed, screen-printed, and heated and dried with a far-infrared heater at 120 ° C. for 3 minutes to form a dielectric layer (D ) Was formed. Furthermore, a commercially available silver carbon paste (TS-5201 manufactured by Tanaka Kikinzoku Kogyo Co., Ltd.) is applied so that the dry film thickness is 12 μm, and dried at 150 ° C. for 3 minutes with a far infrared heater to form the back electrode layer (E). did.

On the transparent conductive layer (B) of the transparent conductive film, a portion where the transparent conductive layer (B) is previously exposed is left, and a copper twisted wire having a total cross-sectional area of 0.2 mm ² is used as a lead wire (F) for soldering. The electrode on the transparent conductive film side is attached, and a copper twisted wire having a total cross-sectional area of 0.2 mm ² is soldered to an arbitrary portion on the silver carbon paste layer as a lead wire (F) to obtain an electrode on the back electrode side. .

  After the electrode is formed, a commercially available UV curable moisture-proof paint (DuPont UV Encap 5018) is screen-printed on the entire inorganic electroluminescence layer side so that the dry film thickness is 25 μm. The resin was heat-dried at 85 ° C. for 2 minutes, and further irradiated with a high-pressure mercury lamp having an energy intensity of 100 w / cm to crosslink and cure the resin to form a moisture-proof layer (G). Twenty-five electroluminescent elements were cut out with a cutter to complete the electroluminescent elements.

As a result of visually judging the warpage and flatness of the completed electroluminescence element, as shown in Table 1, a good electroluminescence element could be obtained. (FIG. 2 shows an example of forming an electroluminescence element)
Example 4
After obtaining a base material (A) composed of a biaxially stretched polyester film (modified) in the same manner as in Examples 1 to 3, the conductive material composed of polyethylene dioxythiophene (PEDOT) and polystyrene sulfonic acid (PSS). A polymer aqueous solution (solid content concentration: 0.7%) (trade name: Orgacon N300 NEW manufactured by Agfa-Gevaert NV) was applied so that the film thickness after drying was 1.2 μm, and a transparent conductive layer (B ) Was formed. Table 1 shows the evaluation results of the obtained transparent conductive film.

  An electroluminescence element was completed in the same manner as in Examples 1 to 3. As a result of visually judging the warpage and flatness of the completed electroluminescence element, as shown in Table 1, a good electroluminescence element could be obtained.

[Comparative Examples 1-3]
The longitudinal direction stretching method of Examples 1 to 3 is maintained as it is, the stretching temperature is 115 ° C., the stretching ratio is 3.5 times, and other products (the description has been revised as the sample of the comparative example was changed). A base material (A) comprising a biaxially stretched polyester film (modified) having the physical properties shown in Table 1 under the same membrane conditions was obtained. Thereafter, a transparent conductive film was completed in the same manner as in Examples 1 to 3.

  The evaluation results of the obtained transparent conductive film are as shown in Table 1. The plane orientation coefficient was high, and the difference in plane orientation coefficient within 50 cm square was also large. A bias was observed in the in-plane orientation of the film due to an increase in the draw ratio.

  Further, an electroluminescence element was completed in the same manner as in Examples 1 to 3. As a result of visual judgment of warpage and flatness of the electroluminescent element after completion, as shown in Table 1, in the comparative example, the directionality of the in-plane orientation of the film was impaired and the orientation was biased. When processed into an electroluminescent element It is thought that the in-plane flatness was lost. This tendency becomes more significant as the thickness of the polymer film becomes thinner. Not only does the flat surface have irregular undulations, but the device warps greatly, and there is no commercial value as an electroluminescence device. (Fixed overall)

  It can be used as a transparent conductive film that is an important constituent material of an electroluminescence element used as a backlight necessary for a display device of information equipment, and a backlight suitable for a particularly thin display device can be provided.

It is the schematic which shows an example of the composite transparent base material cross section of this invention. It is the schematic which shows an example of the electroluminescent element cross section using this invention.

Explanation of symbols

1. Substrate (A) made of polymer film or sheet
2. Transparent conductive layer (B)
3. Phosphor layer (C)
4). Dielectric layer (D)
5. Back electrode layer (E)
6). Lead wire (F)
7). Moisture-proof layer (G)

Claims (12)

  In the transparent conductive film in which the transparent conductive layer (B) is laminated on the biaxially stretched polyester film (A), the plane orientation coefficient defined in the main text in the range of 50 cm square of the biaxially stretched polyester film (A). A transparent conductive film having a difference between a maximum value and a minimum value of 0.007 or less and an average of the plane orientation coefficients of 0.11 to 0.15.   When the biaxially stretched polyester film (A) is heated at 150 ° C. for 30 minutes, the dimensional change rate defined in the text in the longitudinal direction of the film before and after the heating and in the width direction perpendicular thereto is −0.5 to +0. The transparent conductive film according to claim 1, which is within a range of 5%.   The transparent conductive film according to claim 1 or 2, wherein the biaxially stretched polyester film (A) has a melting point of 246 to 280 ° C.   In the biaxially stretched polyester film (A), 95 mol% or more of the constituent components of the polyester are ethylene terephthalate units and / or 2,6-ethylene naphthalate units. Sex film. The relationship of the following formula (1) is satisfied when the thickness of the biaxially stretched polyester film (A) is t (unit: μm) and the absolute value of the difference between the plane orientation coefficients of both surfaces of the substrate is Δf. The transparent conductive film in any one of -4.
0.001 ≦ Δf · t ≦ 0.700 (1)   The transparent conductive layer (B) has a surface resistance measured in accordance with JIS R1637 in the range of 30Ω / □ or more and 1000Ω / □ or less, and its total light transmittance measured in accordance with JIS K7105 is 70. It is% or more. The transparent conductive laminate according to any one of claims 1 to 5.   The transparent conductive film according to claim 1, wherein the transparent conductive layer (B) comprises a metal-based transparent conductive thin film.   The transparent conductive film according to claim 7, wherein the metal-based transparent conductive thin film is composed of a thin film made of a conductive metal oxide.   The transparent conductive film according to claim 8, wherein the metal oxide is a thin film made of at least one compound selected from indium oxide, tin oxide, and zinc oxide.   The transparent conductive film according to claim 1, wherein the transparent conductive layer (B) is made of a conductive polymer.   The conductive polymer is one or two or more kinds of conductive polymers selected from polypyrrole, polythiophene, polyfuran, polyselephene, polyaniline, polyparaphenylene, polyfluorene and derivatives thereof, and copolymers thereof. The transparent conductive film according to claim 10, which is a thin film made of a mixture.   The electroluminescent element comprised using the electroconductive film in any one of Claims 1-11.

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