KR20100034100A - Plastic substrate - Google Patents

Abstract

PURPOSE: A plastic substrate is provided to obtain a clear image by reflecting external light using a reflective metal film of an internal attached reflection material type and to improve a yield by preventing air and moisture contained in the film using the metal film. CONSTITUTION: A plastic substrate comprises a plastic film(100), a metal film(110), and a resin layer(120). The metal film is arranged on the plastic film. The metal film has reflection characteristic. A conductive material is dispersed on the resin layer. The thickness of the metal layer is 10 to 1000nm. Electric conductivity is improved without the degradation of transmittance when including the metal film. The metal film functions as an electrode.

Description

Plastic substrate

The present invention relates to a plastic substrate, an electronic paper display device and a liquid crystal display device including the same.

In recent years, the liquid crystal display device which is characterized by low power consumption, low voltage operation | movement, light weight, thin type, and color display etc. is expanding rapidly to the information apparatus etc .. Among them, a reflective simple matrix liquid crystal display device having low power consumption and requiring no backlight is attracting attention as a portable terminal device.

In the simple matrix liquid crystal display device, stripe-shaped transparent electrodes are formed on two substrates, and two substrates are arranged such that the transparent electrodes are perpendicular to each other. A liquid crystal is sealed between these two base materials, the intersection of two transparent electrodes becomes a pixel electrode, and an image can be displayed by controlling a liquid crystal.

On the other hand, not only the electronic paper display device and the liquid crystal display device, most liquid crystal display devices have conventionally used glass substrates as upper and lower substrates, and thicknesses of the upper and lower glass substrates are gradually reduced to realize weight reduction. However, at present, although the thickness of the substrate is approaching the limit, it is difficult to obtain a light weight that is satisfactory. Therefore, research is being made to change the material of the substrate. As a part of this, a technology using a plastic substrate which is lighter than glass instead of glass is proposed. It became.

However, the plastic substrate may suffer from thermal, chemical, and mechanical damages during the array pattern forming process, the color filter forming process, and the like, thereby degrading the image quality characteristics of the liquid crystal display.

An example of a liquid crystal display device generally including a plastic substrate is briefly illustrated in FIG. 1A, specifically, upper and lower substrates 1 formed of plastic; Upper and lower electrodes 11 applying driving voltages of elements on the upper and lower substrates and formed of transparent electrodes; A partition wall 140 having a constant gap between the upper and lower substrates and having a two-layer structure; It may include a charged particle or a liquid crystal layer 150 injected into the cell formed by the partition particles. At this time, it may include a polarizing plate formed on the outer surface of the plastic insulating substrate used as the upper substrate and a reflecting plate and a transmissive substrate formed on the outer surface of the lower substrate, the black matrix may be formed on the upper plastic insulating substrate to define the unit pixel. The color filter may be provided in the space surrounded by the black matrix. The lower substrate may include a switching element and a pixel electrode for each unit pixel.

As an example of another flat panel display device, a cross-sectional view of an organic EL element is shown in FIGS. 1B to 1C, and the transparent electrode 110 or the reflective electrode 113 is formed on the substrate 1. Has a formed structure.

Although the thickness of the device becomes thinner and lighter with the introduction of the plastic substrate, efforts to reduce the thickness of the device and to reduce the weight of the device by integrating more functions while suppressing the deterioration of the image quality characteristics of the final applied product are still required.

On the other hand, in the reflective liquid crystal display device, since illuminance is obtained by reflecting external light, a reflective material for diffusing and reflecting external light is provided. According to the aspect provided with a reflector, there exist an external reflector system which forms a reflector in the surface on the opposite side to the liquid-crystal layer side of a board | substrate, and the internal-attachment reflector system which forms a reflector in the liquid crystal layer side surface of a board | substrate.

In the external reflector method, since the reflector is formed on the opposite side of the liquid crystal layer side of the substrate, light incident from the outside is diffusely reflected by the reflector, and the reflected light passes through the substrate and then passes through the liquid crystal layer to exit from the display screen. do. At this time, parallax occurs because the reflected light is affected by the thickness of the substrate, which causes an image blur such as a double display of the liquid crystal display or a mixed color display.

On the other hand, in the internal reflection material method, since the reflection material is formed on the surface of the liquid crystal layer side of the substrate, light incident from the outside is diffusely reflected by the reflection material, and the reflected light passes through the liquid crystal layer without passing through the substrate, It is emitted to the outside. In this case, since the reflecting material and the liquid crystal layer are close to each other, and the reflected light is not affected by the substrate thickness, parallax does not occur and image blurring does not occur.

When a board | substrate is a plastic board | substrate, ie, when a film is used, thickness can be made thinner than glass, and the parallax hardly arises by that much. However, when a color filter is provided, since one pixel is divided into color dots of one third size, the reflected light is more likely to pass through other dots than in the case of a single color, and the influence of the film thickness cannot be ignored.

Therefore, even when a film is used as the substrate, in particular, in the colored liquid crystal display device, there is a need to configure the reflector in an internally-attached reflector method.

However, there is a fear that the liquid crystal display device of the internal reflection reflecting method is complicated in structure and difficult to manufacture. In particular, when the film is used as the substrate, the film is easily stretched due to the influence of heat and humidity, and the conditions of the material and the manufacturing process are limited. For this reason, the manufacturing method which can manufacture the liquid crystal display device of the internal reflection reflector system which used the film as a board | substrate according to a design request | requirement can reduce cost and high yield.

In addition, the conventional reflective or semi-transmissive liquid crystal display manufacturing method of the reflective material is formed by photolithography using a photomask to form irregularities on the surface of the resin such as a resist film and to easily reflect light on the uneven surface. A method of forming a film to form a reflector has been proposed.

As another method of forming the irregularities on the surface of the resin, a method of forming the irregularities by the resin in which fine particles are dispersed (Japanese Patent Laid-Open No. H4-267220), phase separation at the time of curing the resin comprising two different components The method of forming an unevenness | corrugation by using it, and the method of forming an unevenness | corrugation by controlling the internal stress at the time of hardening of a light thermosetting resin material, and the like (JP-A-12-171792) are known.

However, when the electrode base material of the liquid crystal display device of the internal reflection type system using a film as a base material is produced by directly forming a reflector etc. on a film, there exist the following problems; Since the reflector needs the function to diffuse-reflect external light, the surface is provided with irregularities. Since this unevenness | corrugation is made by making the surface of a liquid crystal layer into unevenness, there exists a possibility that it may adversely affect liquid crystal drive. For this reason, the technique which performs a high leveling plan especially is needed, a cost rises and there exists a possibility that a yield may fall. Moreover, after forming the metal film used as a reflector, the chemical | medical agent process in the formation process of transparent electrodes etc. may cause damage to the reflector formed previously. In addition, since the film is used as the base material, the film is easily stretched under the influence of heat and humidity, and materials and manufacturing conditions, such as reflectors and transparent electrodes, are limited. Therefore, it is difficult to manufacture a liquid crystal display device according to design requirements. Become. In addition, the above-described problem may be further exacerbated when the electrode substrate of the transflective liquid crystal display device, which can use both the backlight and the reflected light by external light, is formed by directly forming a reflector or the like on the film.

In the case of forming the reflector therein, first, a reflector made of a metal film is formed on the entire surface of the plastic film, and then the pixel of the reflector part made of a metal film corresponding to the part of the pixel of the transparent electrode formed in a subsequent step is applied to the pixel. It is necessary to remove the reflective material of the metal film precisely so that the backlight can transmit the area smaller than the area of the portion to be made.

Then, when forming a transparent electrode above a reflector, the ITO used as a transparent electrode is formed into a film so that the part used as the pixel of a transparent electrode may overlap with the part which removed the reflector made of the metal film, and a resist film is formed on this ITO. It is necessary to adjust the position precisely, to expose and develop the resist film, to remove ITO, and to form a pattern of the transparent electrode. In this case, a high degree of positioning technology is required.

However, in the film made of plastic, elongation occurs only by performing a water washing treatment, and when it is dried, shrinkage occurs in reverse. In addition, these expansion and contraction is not stabilized immediately, but it takes a long time to stabilize. That is, when the film shrinks once, the dimension of the pattern formed on the film causes elongation for a long time, and it is difficult to obtain reproducibility related to positioning as described above.

Therefore, it is difficult to manufacture a transflective liquid crystal display device by directly forming a reflector, a transparent electrode, etc. on a film.

In addition, the conventional method of manufacturing a reflector of a reflective (transflective) type liquid crystal display device has the following problems.

In the method of forming irregularities on the surface of a resin such as a resist film by photolithography, the reflective material acts as a diffraction grating when the pattern of irregularities of the reflective material is simply repeated in the planar direction. Display defects may occur, such as color development in rainbow colors or subtle differences in positional relationships with other repetitive patterns such as wiring and black matrices, so-called moire stripes. For this reason, in the design of the photomask for forming the uneven pattern, it is not possible to use a simple repetitive pattern like a normal pixel pattern, and it is necessary to perform a complicated and difficult design. As such, it is not easy to form a reflector having a suitable diffusivity by ordinary photolithography.

In addition, the method of Unexamined-Japanese-Patent No. 4-267220 is disperse | distributing particle | grains of material different from the resin in resin, and the method of Unexamined-Japanese-Patent No. 12-193707 is phase separation at the time of hardening two different resins. The method disclosed in Japanese Patent Laid-Open No. 12-171792 discloses that part of the surface side of the resin is cured and exposed or baked so as to be uncured, thereby forming irregularities. When the reflective material is directly formed on a plastic film having a film thickness of 50 to 200 µm by such a conventional method for producing a reflective material, warpage is likely to occur in the plastic film due to stress at the time of curing the resin.

In addition, the reflecting material manufactured by the above-mentioned manufacturing method is comprised from the material with which refractive index differs substantially with the interface of resin and particle | grains, or the interface separated from each other. When the uneven surface of the reflecting material is formed on the surface on the opposite side of the liquid crystal layer side of the electrode substrate, incident light polarized on the polarizing plate is reflected by the metal film after passing through the interface of the material with different refractive indexes of the reflecting material through the liquid crystal layer.

At this time, the polarization extinction effect which the polarization degree of light falls easily arises because polarized incident light and the reflected light scattered from the metal film are refracted at the interface of materials with different refractive index. Thereby, when applying the reflecting material arrange | positioned with the structure as mentioned above to a liquid crystal display device, problems, such as the contrast ratio of a liquid crystal display screen, fall easily.

The present invention seeks to provide a plastic substrate which functions as a reflector and serves as a substrate and has light weight and high heat resistance.

The present invention also prevents the dimensional change of the film due to the high temperature generated in the deposition process of the existing transparent electrode ITO by introducing a protective layer or an electrode layer by coating and curing the organic protective layer containing a conductive material on the metal film. To provide a plastic substrate that can be.

An object of the present invention is to provide an electronic paper display device and a liquid crystal display device using a plastic substrate having a high contrast sharp image quality using high light transmittance.

The present invention also provides an electronic paper and a liquid crystal display device having a light weight by including the plastic substrate as a lower substrate.

In one embodiment of the present invention; And it provides a plastic substrate comprising a reflective metal film.

In the plastic substrate according to the embodiment of the present invention, the reflective metal film is aluminum, titanium, silver, platinum, magnesium, Single or an alloy thereof selected from tantalum and palladium, or A metal film including ITO or IZO, which may be a single layer or multiple layers of the same or different materials.

In particular, the reflective metal film may be aluminum or an alloy thereof, or magnesium or an alloy thereof.

According to another embodiment, the reflective metal film may include a lower metal film made of aluminum or an alloy thereof, or magnesium or an alloy thereof; And an upper metal film made of ITO or IZO.

In the plastic substrate according to the embodiment of the present invention, the reflective metal film may have a thickness of 10 to 1000 nm, and according to one specific embodiment, the reflective metal film may have a thickness of 50 to 300 nm.

In the plastic substrate according to one embodiment of the present invention, the plastic film may be a polyimide film.

In the plastic substrate according to a preferred embodiment of the present invention, the plastic film has an average coefficient of linear expansion (CTE) of 50.0 ppm / ° C. measured in a range of 50 to 250 ° C. by thermomechanical analysis based on a film thickness of 50 to 100 μm. It may be a polyimide film having a yellowness of 15 or less, and the plastic film has an L value of 90 or more and an a value of 5 or less when the color coordinate is measured by a UV spectrophotometer based on a film thickness of 50 to 100 μm. It may be a polyimide film having a b value of 5 or less.

The plastic substrate according to another embodiment of the present invention may further include a protective layer formed on the reflective metal film.

In this case, the protective layer may be a polyimide layer having an average linear expansion coefficient (CTE) of 50.0 ppm / ° C. or less and a yellowness of 15 or less, measured in the range of 50 to 250 ° C. by thermomechanical analysis based on a thickness of 50 to 100 μm. For example, the protective layer may be a polyimide layer having an average transmittance of 85% or more at 380 to 780 nm when the transmittance is measured with a UV spectrophotometer based on a thickness of 50 to 100 μm. In addition, the protective layer may be a polyimide layer having a transmittance of 88% or more at 550 nm and a transmittance of 70% or more at 420 nm when the transmittance is measured by a UV spectrophotometer based on a thickness of 50 to 100 μm.

The plastic substrate according to another embodiment of the present invention may include a resin layer in which a conductive material is dispersed on the reflective metal film. Another plastic substrate may include a resin layer in which a conductive material is dispersed on a protective layer.

In this case, the conductive material may be carbon nanotubes or ITO powder, and the resin layer in which the conductive material is dispersed may be formed from a polyimide varnish in which the conductive material is dispersed. According to a preferred embodiment, the resin layer in which the conductive material is dispersed may be formed from a varnish containing 0.001 to 1 parts by weight of carbon nanotubes based on 100 parts by weight of the polyimide resin solid content. According to another embodiment, the resin layer in which the conductive material is dispersed may be formed from a varnish containing 2 to 100 parts by weight of ITO powder based on 100 parts by weight of the polyimide resin solid content. At this time, the ITO powder may contain 80 to 95% by weight of indium oxide and 5 to 20 parts by weight of tin oxide.

In the plastic substrate according to the embodiment of the present invention, the resin layer in which the conductive material is dispersed may have a thickness of 10 nm to 25 μm.

Plastic substrate according to an exemplary embodiment of the present invention may be to include a chemical resistant layer formed on at least one side of the plastic film. In this case, the chemical resistant layer may be at least one resin layer selected from acrylate-based, epoxy-based, and polyimide-based resins.

Plastic substrate according to an exemplary embodiment of the present invention may be to include an inorganic layer formed on the lower portion of the plastic film.

The plastic substrate according to the exemplary embodiment of the present invention may include an inorganic layer formed under the reflective metal film.

The plastic substrate according to embodiments of the present invention may be a lower substrate of the transmissive electronic paper and the display device.

An exemplary embodiment of the present invention provides an electronic paper device including a plastic substrate including a plastic film and a reflective metal film as a lower substrate.

An exemplary embodiment of the present invention provides a liquid crystal display device including a plastic substrate including a plastic film and a reflective metal film as a lower substrate.

An exemplary embodiment of the present invention provides an OLED display device including a plastic substrate including a plastic film and a reflective metal film as a lower substrate.

The plastic substrate according to the present invention includes a reflective metal film, and when applied in the form of an internal reflective material, for example, light incident from the outside of the liquid crystal display is diffusely reflected by the metal film formed on the plastic film, and reflected light. Since it does not penetrate the plastic film, parallax is less likely to occur, and a clear image without blurring is obtained, and the metal film can block not only external air or moisture but also air or moisture contained in the film itself, so that the liquid crystal of the plastic film is especially Since it is not necessary to form a gas barrier layer on the side of the layer side, the cost can be further reduced and the yield can be improved, which is useful as a lower substrate in electronic paper display devices and liquid crystal display devices, and includes it as a lower substrate. As a result, it is possible to reduce the weight of the display device.

Hereinafter, the present invention will be described in more detail.

The present invention relates to a plastic substrate for use in electronic paper display elements, liquid crystal display devices and the like.

2 shows an example of a plastic substrate according to the present invention, referring to the plastic film 100; The metal film 110 is disposed on the plastic film and has a reflective property, and may further include a resin layer 120 in which a conductive material is dispersed.

In a subsequent process such as forming a metal film through direct deposition on the plastic film 100 or performing a TFT ARRAY process on the film, the film may be affected by heat or humidity. Can cause stretching. As a result, the plastic film constituting the plastic substrate may be limited due to limited process conditions, misalignment with subsequent layers or members, or failure to maintain horizontal (flattening) film. 100) is advantageous as the glass transition temperature is 250 ° C. or higher and the coefficient of linear expansion is small. Specifically, the average linear expansion measured in the range of 50 to 250 ° C. by the Thermomechanical Analyzer based on the film thickness of 50 to 100 μm. It may be advantageous that the coefficient (CTE) is a high heat resistant film having 50.0 ppm / ° C. or less, preferably 35.0 ppm / ° C. or less. An example thereof may include a polyimide film, but is not limited thereto.

In addition, in terms of permeability, a colorless and transparent plastic film, specifically, a polyimide film having a yellowness of 15 or less based on a film thickness of 50 to 100 μm may be preferable. In addition, a polyimide film having an average transmittance of 85% or more at 380 to 780 nm may be used as a plastic film when the transmittance is measured with a UV spectrophotometer based on a film thickness of 50 to 100 μm. When such a transparency is satisfied, it can be used as a plastic substrate for a transmissive electronic paper and a liquid crystal display device. Furthermore, the plastic film may be a polyimide film having a transmittance of 88% or more at 550 nm and a transmittance of 70% or more at 420 nm when the transmittance is measured by a UV spectrophotometer based on a film thickness of 50 to 100 μm.

In addition, when the reflective metal film is formed on the base film from the side of the reflective display using the reflective metal film of the present invention, the yellow film has a yellowness of 15 or more, based on a film thickness of 50 to 100 μm, and a UV spectrophotometer. When the transmittance is measured, a polyimide film or a plastic film having an average transmittance of 85% or less at 380 to 780 nm may also be used as the substrate. As described above, the reflective display including the reflective metal film on the base film can be used as a plastic substrate for reflective electronic paper, liquid crystal display, and OLED display regardless of the transmittance of the base film.

In addition, in terms of improving transparency by increasing transparency, the polyimide film has an L value of 90 or more, a value of 5 or less, and b value of 5 when color coordinates are measured with a UV spectrophotometer based on a film thickness of 50 to 100 μm. It may be the following polyimide film.

Such a polyimide film can be obtained by polymerizing an aromatic dianhydride and a diamine to obtain a polyamic acid, and then imidizing it. Examples of the aromatic dianhydride include 2,2-bis (3,4-dicarboxy). Phenyl) hexafluoropropane dianhydride (6-FDA), 4- (2,5-dioxotetrahydrofuran-3-yl) -1,2,3,4-tetrahydronaphthalene-1,2-dica Carboxyl anhydride (TDA) and 4,4 ′-(4,4′-isopropylidenediphenoxy) bis (phthalic anhydride) (HBDA), pyromellitic dianhydride (PMDA), One or more selected from biphenyltetracarboxylic dianhydride (BPDA) and oxydiphthalic dianhydride (ODPA), but is not limited thereto.

Examples of the aromatic diamine include 2,2-bis [4- (4-aminophenoxy) -phenyl] propane (6HMDA), 2,2'-bis (trifluoromethyl) -4,4'-diamino Biphenyl (2,2'-TFDB), 3,3'-bis (trifluoromethyl) -4,4'- diaminobiphenyl (3,3'-TFDB), 4,4'-bis ( 3-aminophenoxy) diphenylsulfone (DBSDA), bis (3-aminophenyl) sulfone (3DDS), bis (4-aminophenyl) sulfone (4DDS), 1,3-bis (3-aminophenoxy) benzene (APB-133), 1,4-bis (4-aminophenoxy) benzene (APB-134), 2,2'-bis [3 (3-aminophenoxy) phenyl] hexafluoropropane (3-BDAF ), 2,2'-bis [4 (4-aminophenoxy) phenyl] hexafluoropropane (4-BDAF), 2,2'-bis (3-aminophenyl) hexafluoropropane (3,3 ') -6F), 2,2'-bis (4-aminophenyl) hexafluoropropane (4,4'-6F) and oxydianiline (ODA), but is not limited thereto. .

There is no particular limitation in the method for producing a polyimide film using such a monomer, and as one example thereof, the aromatic diamine and the aromatic dianhydride are polymerized under a first solvent to obtain a polyamic acid solution. After imidizing the mixed acid solution, the imidized solution was added to the second solvent, filtered and dried to obtain a solid content of the polyimide resin, and a polyimide solution obtained by dissolving the obtained polyimide resin solid content in the first solvent was formed into a film. It can form into a film through a process. In this case, the second solvent may be lower in polarity than the first solvent, and specifically, the first solvent may be m-crosol, N-methyl-2-pyrrolidone (NMP), dimethylformamide (DMF), or dimethylacetate. At least one selected from amide (DMAc), dimethyl sulfoxide (DMSO), acetone, and diethyl acetate, and the second solvent may be at least one selected from water, alcohols, ethers, and ketones.

Meanwhile, in order to form a metal film having a uniform thickness in forming a metal film on the plastic film, the surface smoothness of the plastic film may be 2 μm or less, preferably 0.001 to 0.04 μm.

Since the reflective metal film 110 (hereinafter referred to as a "reflective metal film") is formed on the plastic film, the metal film is advantageously formed as a thick film in consideration of reflectivity. Is 10 to 1000 nm.

In order to improve the transmittance as compared to the reflective function, for example, when used in the transmission type electronic paper and the liquid crystal display device, the metal film is advantageously formed into a thin film. Preferably, the metal film is about 50 to 300 nm. There is no deterioration in optical properties such as transmittance, and there is an advantage of lowering the coefficient of linear expansion due to the metal film deposited on the surface of the plastic film substrate.

If the thickness of the metal film is too thick, the reflectivity or conductivity is increased, but there is a risk of cracking when bending the plastic film.

In this case, the metal film may be made of aluminum, titanium, silver, platinum, magnesium , tantalum, and palladium alone or an alloy thereof, or a film including ITO (Indium-Tin-Oxide) or IZO (Indium-Zinc-Oxide). It can be.

In the case of including such a reflective metal film, the electrical conductivity can be improved without hindering transmittance, and the reflective metal film can function as an electrode. In this regard, the reflective metal film may include an ITO or IZO thin film on top of the reflective metal film made of aluminum or an alloy thereof, or magnesium or an alloy thereof.

Such a reflective metal film is advantageous in terms of electrical conductivity, and may also perform a function of suppressing deformation of the plastic film by gas or moisture by expressing gas barrier properties and / or moisture barrier properties.

Formation of the reflective metal film on the plastic film may use sputtering, ion deposition, electroplating, or chemical vapor deposition, and the like, but is not particularly limited thereto.

According to one embodiment of the present invention, since a high heat resistant film is used as the plastic film, the process conditions for forming the reflective metal film are hardly limited as compared with the conventional plastic substrate.

When the reflective metal film is formed on the plastic film as described above, when it is applied in the form of an internal reflection reflector, light incident from the outside of the liquid crystal display device is diffusely reflected on the metal film formed on the plastic film, Since light does not penetrate the plastic film, parallax is hardly produced, and a clear image without image blur can be obtained.

Formation of the metal film on the plastic film may use sputtering, ion deposition, electroplating or chemical vapor deposition, and the like, but is not particularly limited thereto.

Plastic substrate according to an embodiment of the present invention is a resin layer 120 in which a conductive material is dispersed, specifically, carbon nanotubes directly on the reflective metal film 110 or on the protective layer 103 to be described later. Alternatively, the resin layer in which the ITO powder is dispersed may be further formed. The resin layer in which the carbon nanotubes or the ITO powder is dispersed may further improve conductivity and also function as an additional electrode layer. The resin layer in which carbon nanotubes or ITO powder is dispersed may be a layer obtained by applying a transparent varnish containing carbon nanotubes or ITO powder, and a layer formed by dispersing carbon nanotubes or ITO powder in a transparent polyimide varnish. Can be.

In this case, the carbon nanotubes in the polyimide varnish may be included in an amount of 0.001 to 1 parts by weight based on 100 parts by weight of the resin solids content in the varnish in terms of surface resistance and light transmittance of the electrode film for display.

On the other hand, carbon nanotubes are not limited in their kind, and single-walled carbon nanotubes (SWCNT), double-walled carbon nanotubes (DWCNT), multi-walled carbon nanotubes (MWCNT), and carbon nanotube surfaces are chemically or physically treated. Modified-carbon nanotubes and the like.

In addition, the method of dispersing carbon nanotubes in the varnish is not particularly limited. For example, ultrasonic dispersion, three-roll dispersion, homogenizer or physical dispersion and chemical treatment of Kneader, Mill-Blender, Ball Mill, etc. It is possible to disperse carbon nanotubes in varnishes by chemical bonding, etc.In this case, CNT can be added as in-situ during polymerization of varnish or blending after polymerization of varnish, and dispersed for proper phase separation of CNT. The method of using additives, such as an agent and an emulsifier, etc. are mentioned.

The carbon nanotube-dispersed resin layer may be formed by a spin coating method, a casting method such as a doctor blade, a spray coating method, or the like, but is not limited thereto.

Particularly, since the light that is not affected by the transmittance through the metal thin film can improve the conductivity without being particularly inhibited by the transmittance due to the unique structure of the carbon nanotubes, the resin layer in which the carbon nanotubes are dispersed is made of metal. It is preferable to form on a film | membrane.

When using ITO powder with or in place of carbon nanotubes, the content thereof may be 2 to 100 parts by weight based on 100 parts by weight of the resin solids content in the varnish.

When the ITO powder is added, the electrical properties can be adjusted according to the content of the indium-tin mixed oxide, and can also be controlled by adjusting the content of indium oxide and tin oxide in the indium-tin mixed oxide itself. The indium-tin mixed oxide (ITO) may preferably contain 80 to 95% by weight of indium oxide (In ₂ O ₃ ) and 5 to 20% by weight of tin oxide (SnO ₂ ). The indium-tin mixed oxide may be in powder form, the size of which depends on the material used and the reaction conditions, preferably having an average minimum diameter of 30 to 70 nm and an average maximum diameter of 60 to 120 nm.

The manufacturing method of the varnish containing the indium-tin mixed oxide is not particularly limited, but the indium-tin mixed oxide may be dispersed in a polyamic acid solution, and the indium-tin mixed oxide may be dispersed in 100 parts by weight of the polyamic acid solid content. ITO) to include 2 to 100 parts by weight may be advantageous in terms of maintaining the expression of the conductivity or the ductility of the film.

The method of adding the indium-tin mixed oxide in the polyamic acid solution is not particularly limited, but for example, a method of adding the indium-tin mixed oxide to the polyamic acid solution before or during polymerization, or kneading the indium-tin mixed oxide after completion of the polyamic acid polymerization The method, the method of preparing the dispersion liquid containing an indium-tin mixed oxide, and mixing this into a polyamic-acid solution are mentioned. In this case, the dispersibility of the indium-tin mixed oxide is affected by the acid-base and viscosity of the dispersion solution, and the dispersion process must be sufficiently performed because it affects the uniformity of the conductivity and the visible light transmittance. Preferred dispersion methods include triple rolls, ultrasonic dispersers, homogenizers or ball mills and the like.

Thus, in forming the resin layer in which the CNT or ITO powder is dispersed, the thickness of 10 nm to 25 μm may be advantageous in terms of suppressing the deterioration of optical properties such as transmittance of the display.

The plastic substrate according to another embodiment of the present invention may further include a layer for preventing solvent penetration into the substrate and the electrode. In the present invention, such a layer is referred to as a chemical resistant layer.

3 to 5 illustrate an example of a plastic substrate on which a chemical resistant layer is formed, and FIGS. 3 and 5 illustrate an example of forming the chemical resistant layer 102 on a lower portion of the plastic film 100. 4 illustrates an example in which the chemical resistant layer 102 is formed on and under the plastic film 100.

The composition used for forming the chemical resistant layer 102 is particularly limited so long as it is a composition that satisfies conditions of good insolubility in organic solvents and good insolubility with an organic solvent in a display manufacturing process without impairing transparency. As a specific example, the layer may include at least one resin selected from an acrylate resin, an epoxy resin, and a polyimide resin.

Forming the chemical resistant layer 102 under the plastic film 100 may prevent solvent penetration from the outside of the plastic film, and forming the chemical resistant layer 120 on the plastic film 100 may be a solvent. In addition to the function of preventing immersion, it may help to form the reflective metal film 110 on the plastic film 100.

The method of forming the chemical resistant layer 102 is not particularly limited, but for example, spin coating, casting, roll coating, or the like may be used.

Although the thickness of the chemical resistant layer 102 is not limited, the thickness of about 10 nm to 500 nm may be advantageous in terms of not impairing optical properties such as thickness uniformity and transmittance.

The plastic substrate according to another embodiment of the present invention may further form a protective layer (flattening layer) after forming the reflective metal film 110, an example of which is illustrated in FIG. 5. The protective layer 103 serves to protect the reflective metal film and to smooth the surface of the reflective metal film, and subsequently facilitates the formation of the resin layer 120 in which the conductive material is dispersed, and prevents occurrence of warping of the plastic substrate. It may be advantageous in terms of what it can do. In this respect, the protective layer may be advantageously provided with insulation without inhibiting the transmission of light reflected through the reflective metal film.

In this regard, a protective layer can be formed of a polyimide resin layer such as a polyimide film exemplified as a plastic film. For example, the protective layer is advantageously a colorless transparent resin layer having a visible light transmittance of 85% or more.

The thickness of the protective layer 103 may be sufficient to planarize the uneven surface due to the reflective metal film 110, and the thickness of the protective layer 103 is not limited, but considering the adhesive strength with the metal film layer and the ease of deposition of the organic light emitting layer. 10 nm to about 500 nm.

Plastic substrate according to another embodiment of the present invention may be provided with an inorganic layer. The plastic substrate is made of the plastic film 100 as a substrate, and since the film itself contains air or moisture, and the air permeability and moisture permeability are high, air or moisture is transferred from the outside air or the film itself to the liquid crystal layer or the organic light emitting element layer. There is a possibility that bubbles may be generated by intrusion, or the liquid crystal and the organic light emitting element may be oxidized by moisture and oxygen, resulting in deterioration and deterioration of the life of the display device. To this end, an inorganic layer may be formed on the inner surface or the outer surface of the plastic substrate as a single layer or a multilayer to be used as a barrier layer to block gas and moisture. That is, not only the air or moisture which flows in from the outside but also the air or moisture contained in the film itself can be interrupted | blocked.

An example thereof is illustrated in FIGS. 6 to 7.

6 illustrates an example in which the inorganic layer 101 is formed below the plastic film 100, and FIG. 7 illustrates a lower surface of the plastic film 100 and a lower surface of the resin layer 120 in which the conductive material is dispersed. The case where the inorganic layer 101 was formed, respectively is shown.

Of course, the reflective metal film 110, the oxide film 111, etc. may also be useful as a water and gas barrier layer without the inorganic material layer as described above, but as an embodiment for providing more sufficient water and gas barrier properties, the inorganic material The layer 101 may be further provided.

SiOx, SiNx, Al ₂ Ox-based oxides and the like may be used for the formation of the inorganic layer 101, and the formation method is not limited, and generally known inorganic deposition such as low temperature film formation method, high temperature film formation method, PECVD, etc. Method can be used. Although the thickness of the inorganic layer 101 is not limited thereto, the thickness of the inorganic layer 101 may be about 10 nm to 300 nm in consideration of the ease of deposition of the organic light emitting layer and the low permeability of gas and moisture to prevent oxidation of the metal layer, the organic layer, and the liquid crystal layer. . Moreover, a multilayer of 2-4 layers can also be formed with a protective layer.

The plastic substrate according to the embodiments of the present invention thus obtained is useful as a substrate in electronic paper display devices and flat panel display device devices, and when used as a lower substrate without a reflective metal film, without impairing the transmittance of light incident from the rear surface. The electrical conductivity is improved to achieve bright images in the transmissive display.

As such, since the substrate is made of plastic, the substrate may serve as a reflector and a transparent electrode substrate, thereby reducing the weight of the liquid crystal display.

The plastic substrate according to the present invention is useful as a lower substrate such as a reflection type electronic paper and a liquid crystal display device that implements an image by reflecting light from the outside without having an internal light source.

If the metal film is to be patterned, it is also useful as a semi-transparent electronic paper and a lower substrate such as a liquid crystal display device. For example, a metal film made of a reflective material forms a pattern at a portion corresponding to the periphery of the pixel portion of the transparent electrode. In the center of the pixel portion, for example, the portion where the metal film is removed is smaller than the area of the pixel portion, for example, in a state where the position of the pixel portion is approximately 10-20%).

In this way, the plastic substrate may be used in the transflective liquid crystal display device by adding a pattern process. In other words, when the backlight is used as the light source, the image can be displayed by transmitting light through a portion of the reflector corresponding to the pixel portion where no metal film exists. In addition, when external light is used as the light source, the external light is reflected at the portion where the metal film exists among the reflector portions corresponding to the pixel portion to display an image.

In addition, in the case of a plastic substrate, in order to form a reflective metal film and use it as an electrode, the thickness of the reflective metal film deposited on the plastic film becomes thick, which causes peeling and metal layers due to a difference in flexibility between the plastic substrate and the metal layer when the plastic substrate is bent. This can cause cracks, which can lead to loss of electrode function. However, in the case of the plastic substrate according to the embodiment of the present invention, the thickness of the reflective metal film may be reduced by introducing a resin layer in which a conductive material is dispersed along with the reflective metal film, and the reflective metal film and the reflective film on the plastic film and the film Since the resin of the resin layer in which the conductive material on the metal film is dispersed can reduce the problem of peeling and cracking of the reflective metal film due to the difference in the dimensional stability generated when bending, the display of the reflective metal film as compared to the single electrode layer of the conventional reflective metal film. And peeling resistance and uniformity against bending of the substrate can be improved.

According to the present invention, there is no particular limitation on a method of manufacturing a plastic substrate including a plastic film, a metal film, a protective layer, and a transparent electrode layer, and examples thereof include preparing a polyimide precursor solution comprising a plastic film; Producing a solution containing a partially cured intermediate by at least partly ring closing, condensing, crosslinking or polymerizing a portion of the precursor in the precursor solution; Preparing a coating liquid based on a solution containing a partially cured intermediate; Applying a coating liquid onto the workpiece; Obtaining a plastic film by heating and completely curing the coating liquid; And forming a protective layer for planarizing the surface of the metal film using the resin. And forming a resin layer including a conductive material on the surface of the metal film to form a transparent electrode layer.

Hereinafter, the present invention will be described in detail with reference to Examples, but the present invention is not limited to these Examples.

<Production of Plastic Film>

Preparation Example 1

2,2'-bis (trifluoromethyl) -4,4'-diaminobiphenyl (2,2'-TFDB) and biphenyl tetracarboxylic dianhydride (BPDA) and 2,2-bis A polyimide precursor solution (solid content 20%) was obtained by condensing (3,4-dicarboxyphenyl) hexafluoropropane dianhydride (6-FDA) in dimethylacetamide by a well-known method. This reaction process is shown in Scheme 1 below.

Subsequently, 300 g of this polyimide precursor solution was added with 2 to 4 equivalents of acetic anhydride (Acet oxide) and pyridine (Pyridine) as a chemical curing agent according to the above-mentioned procedure. After heating the polyamic acid solution at a temperature in the range of 20 to 180 ° C. at a rate of 1 to 10 ° C./min for 2 to 10 hours, the polyamic acid solution was partially imidized and cured by partially imidizing (partially curing). Korean) A solution containing an intermediate was prepared.

The following Reaction Scheme 2 shows a process of heating a precursor of polyimide to obtain a polyimide film. In the embodiment of the present invention, the precursor solution is not completely imidized to form a polyimide, but imidates only a predetermined proportion of the precursor. It was to use one.

More specifically, the polyimide precursor solution is heated and stirred under predetermined conditions to dehydrate and close the ring between the hydrogen atom and the carboxyl group of the amide group of the polyimide precursor, as shown in the following formula (1). Similarly, the form B of the intermediate portion and the form C of the imide portion are generated by the reaction. Further, in the molecular chain, form A (polyimide precursor portion) in which dehydration does not occur completely also exists.

That is, in the molecular chain in which the polyimide precursor was partially imidized, as shown in the following formula (1), structures of the shape A (polyimide precursor part), the shape B (intermediate part), and the shape C (imide part) are mixed. Will be.

Therefore, 30 g of the imidized solution mixed with the above structure was added to 300 g of water to precipitate, and the precipitated solid was finely powdered through filtration and grinding, followed by drying in a vacuum drying oven at 80 to 100 ° C. for 2 to 6 hours. To about 8 g of a resin solid powder. Through the above process, the polyimide precursor portion of [Form A] is converted into [Form B] or [Form C], and the resin solid content is dissolved in 32 g of DMAc or DMF, which is a polymerization solvent, to prepare a 20 wt% polyimide solution. Got it. This was heated for 2 to 8 hours while the temperature was raised at a rate of 1 to 10 ° C./min in a temperature range of 40 to 400 ° C. to obtain a polyimide film having a thickness of 50 μm and a thickness of 100 μm.

When the polyimide precursor partially imidated, the reaction scheme is shown in Scheme 3.

For example, under the above conditions, about 45 to 50% of the precursor is imidized and cured. The imidation ratio which a part of a precursor imidates can be easily adjusted by changing heating temperature, time, etc., and it is preferable to set it as about 30 to 90%.

In the step of imidizing a part of the polyimide precursor, water is generated when the polyimide precursor is dehydrated and closed and imidized, and this water causes hydrolysis of the amide of the polyimide precursor, cleavage of molecular chains, or the like. Since there is a risk of lowering the stability, the Azeotropic reaction using toluene, xylene, or the like is added during heating of the polyimide precursor solution or removed through volatilization of the above-mentioned dehydrating agent.

Next, an example of the process of manufacturing a coating liquid is demonstrated. First, a uniform coating liquid is prepared in the ratio of 100 weight part of solutions and 20-30 weight part of polyimide precursors to the solvent which used the partially hardened intermediate at the time of manufacture of a polyimide precursor.

Subsequently, the resin solution was cast on a film-coated plate for film or film formation such as Sus using spin coating or a doctor blade, and then a film having a thickness of 50 μm was formed through the above-mentioned high temperature drying process. In this case, the film formed was formed with the same refractive index on the entire surface of the film because the film is not subjected to a process in which only one surface is stretched based on the vertical / horizontal axis of one side of the film.

Production Example 2

The reactor was filled with 34.1904 g of N, N-dimethylacetaamide (DMAc) while passing nitrogen through a 100 ml 3-Neck round bottom flask equipped with a stirrer, a nitrogen injector, a dropping funnel, a temperature controller and a cooler. After lowering the temperature to 0 ° C., 4.1051 g (0.01 mol) of 6-HMDA was dissolved to maintain this solution at 0 ° C. 4.4425 g (0.01 mol) of 6-FDA was added thereto and stirred for 1 hour to completely dissolve 6-FDA. At this time, the concentration of the solid was 20% by weight, after which the solution was left at room temperature and stirred for 8 hours. At this time, the solution viscosity at 23 degreeC was obtained the polyamic-acid solution of 2400 cps.

After completion of the reaction, the polyamic acid solution obtained was cast to a thickness of 500㎛ ~ 1000㎛ by using a doctor blade on a glass plate and dried in a vacuum oven for 1 hour at 40 ℃, 2 hours at 60 ℃ to obtain a self standing film A polyimide film having a thickness of 50 μm was obtained by heating at 80 ° C. for 3 hours at 100 ° C., 1 hour at 100 ° C., 1 hour at 200 ° C., and 30 minutes at 300 ° C. in a high temperature furnace oven.

Production Example 3

6-HMDA 2.87357g (0.007mol) was dissolved in 32.2438g of N, N-dimethylacetaamide (DMAc) in Preparation Example 2, and 4-449 DDS 0.7449g (0.003mol) was completely dissolved, followed by 6-FDA. 4.4425 g (0.01 mol) was added and stirred for 1 hour to completely dissolve 6-FDA. At this time, the concentration of the solid was 20% by weight, after which the solution was left at room temperature and stirred for 8 hours. At this time, the polyamic-acid solution whose solution viscosity in 23 degreeC is 2300 cps was obtained.

Thereafter, a polyimide film was prepared in the same manner as in Preparation Example 2.

Preparation Example 4

In Preparation Example 2, 4.1051 g (0.01 mol) of 6-HMDA was dissolved in 32.4623 g of N, N-dimethylacetaamide (DMAc), and 3.1097 g (0.007 mol) of 6-FDA was added, followed by TDA 0.90078 g (0.003). mol) was added and stirred for 1 hour to completely dissolve 6-FDA and TDA. At this time, the concentration of the solid was 20% by weight, after which the solution was left at room temperature and stirred for 8 hours. At this time, the polyamic-acid solution whose solution viscosity in 23 degreeC is 2200 cps was obtained.

Thereafter, a polyimide film was prepared in the same manner as in Preparation Example 2.

Preparation Example 5

In Preparation Example 2, 2.9233 g (0.01 mol) of APB-133 was dissolved in 29.4632 g of N, N-dimethylacetamide (DMAc), and 4.4425 g (0.01 mol) of 6-FDA was added thereto, followed by stirring for 1 hour. 6-FDA was completely dissolved. At this time, the concentration of the solid was 20% by weight, after which the solution was left at room temperature and stirred for 8 hours. At this time, the polyamic-acid solution whose solution viscosity in 23 degreeC is 1200 cps was obtained.

Thereafter, a polyimide film was prepared in the same manner as in Preparation Example 2.

Physical properties of the polyimide films obtained from Preparation Examples 1 to 5 were measured as follows, and are shown in Table 1 below.

(1) transmittance and color coordinate

The prepared film was measured for visible light transmittance using a UV spectrometer (Varian, Cary 100).

In addition, using the UV spectrometer (Varian, Cary100) was measured for the color coordinates according to the ASTM E 1347-06 standard, the light source (Illuminant) was based on the measured value by CIE D65.

(2) yellowness

Yellowness was measured according to ASTM E313.

(3) coefficient of linear expansion (CTE)

TMA (TA Instrument, Inc., Q400) was used to measure the average coefficient of linear expansion at 50-250 ° C. according to TMA-Method.

division Thickness (㎛) Coefficient of linear expansion (ppm / ℃) Yellow road Permeability Color coordinates 380 nm to 780 nm 551 nm to 780 nm 550 nm 500 nm 420 nm L a b  Manufacture example One 50 21.6 2.46 86.9 90.5 89.8 89.3 84.6 96.22 -0.27 1.03 2 50 46 1.59 87.6 90.0 89.7 89.2 85.4 95.85 -0.12 0.99 3 50 35 2.76 87.9 89.6 89.5 89.0 58.6 95.61 -0.42 1.91 4 50 40 3.45 88.2 90.0 89.8 89.3 60.1 95.56 -0.49 2.05 5 50 46.0 6.46 83.8 88.8 87.2 84.8 73.2 94.6 0.59 5.09

Example  1 to 6 and comparative samples

On each of the plastic films (thickness 50 μm) obtained from Production Examples 1 to 5, a reflective metal film was formed by depositing a reflective metal as shown in Table 2 below, and reflectance of the formed metal film was measured.

The structure of the reflecting material used for evaluation of a reflection characteristic is demonstrated.

First, by forming a metal film on the surface of the plastic substrate by the above-described manufacturing method, and forming an electrode layer using a transparent plastic protective layer or a transparent plastic resin on the metal film, the plastic of the plastic substrate and the metal film formed thereon The board | substrate was manufactured and it was set as the evaluation sample.

The evaluation of the reflective characteristics is that the external light passes through the front portion of the liquid crystal display device as the metal film is formed under the transparent protective layer or the transparent electrode layer in the structure of the reflective liquid crystal display device in the plastic substrate. After passing through the polyimide film, the metal film was diffusely reflected.

The measuring system used for the measurement of the luminance of the reflecting material will be described.

As an example thereof is shown in Fig. 8, the luminance meter is arranged at a predetermined position on the upper portion of the plastic substrate on which the reflecting plate is formed, and the light source is arranged on the side surface of the reflecting plate. The angle formed by the incident light emitted from the light source and the reflected light is defined as the incident angle θ, and the light source can move to a predetermined position so as to vary the incident angle θ. White light was used as a light source, and the polarizing film was used as the measuring system. Subsequently, the white light is emitted from the light source while the incident angle θ is changed to a range of 7.4 ^{° to} 35.6 ^° , and the luminance angle of the light reflected by the metal film is measured by a luminance meter to investigate the dependence of the incident angle θ on the luminance. It was.

In addition, a ceramic type standard white diffuser plate was prepared, and the incident angle θ dependence of the luminance of light reflected from the standard white diffuser plate was measured by the above-described measuring method, and this was taken as the reference value of the light reflection luminance.

Then, the luminance value obtained from the plastic substrate was divided by the luminance value of the standard white diffuser plate, and the value obtained by multiplying this by 100 was obtained. That is, the relative luminance value of the plastic substrate when the luminance of the standard white diffuser plate was set to 100 was obtained.

On the other hand, the resist film provided with the unevenness | corrugation on the surface side formed on the base material, and the reflector which consists of the aluminum film formed on it were prepared. This reflector is generally used as a reflector of a reflective liquid crystal display device, and this was used as a comparative sample. Subsequently, the dependence of the incident angle (theta) dependence of the brightness | luminance of the light reflected by the comparative sample was investigated by the same method as the above, and the relative luminance value of the comparative sample when the luminance of the standard white diffuser plate was set to 100 was calculated | required.

The results are shown in Table 2 below.

  Plastic film  Reflective metal film  Reflective property evaluation  Kinds Thickness (nm) 7.4 ^о 17.7 ^о 22.3 ^о 26.6 ^о 31.8 ^о 35.6 ^о Example 1 Preparation Example 1 Mg 10 486 249 196 112 91 14 Example 2 Production Example 2 Mg 10 470 267 218 122 109 19 Example 3 Preparation Example 5 Mg 50 468 264 204 128 112 14 Example 4 Preparation Example 1 Al 10 493 278 218 99 91 11 Example 5 Production Example 2 Al 10 487 280 220 130 116 15 Example 6 Preparation Example 5 Al 50 476 284 210 138 122 29 Comparative Sample - - - 443 279 222 173 134 91

From the results in Table 2, the evaluation results of the reflection characteristics in the plastic substrate according to the metal film formation are explained. When the incident angles θ are 7.4 ^° , 17.7 ^° and 22.3 ^° , the luminance of the comparative sample and the reflected light is almost equal. However, luminance of about 2.2 to 4.4 times was obtained for the standard white diffuser plate.

As described above, the plastic substrate manufactured by the method of manufacturing the reflector according to the embodiment of the present invention obtains higher luminance than the standard white diffuser at most incident angles of the light, and at the same time the incident light having a large incident angle? It was found that the luminance of the reflection of the incident light on the side surface can be made higher than that of the comparative sample.

Alternatively, although the evaluation was performed in a state in which a transparent electrode layer was formed on a metal film in a plastic substrate, that is, a structure in which incident light was diffused and reflected through a polyimide film, a light reflectance higher than that of a standard white diffuser plate was obtained. Since the polyimide membrane had high transparency, it was confirmed that there was no problem even in such a structure.

In addition, it goes without saying that even in the form in which light is emitted from the metal film side, it has a reflection characteristic equivalent to or higher than the present evaluation result.

In addition, since the plastic substrate of the present invention has the same refractive index over the entire polyimide film, even when the incident light is arranged to diffusely reflect through the polyimide film, it can be used as a reflective material with little occurrence of polarization extinction effect.

That is, although not specifically stated, in the above-described measuring system, the luminance La when the polarizing films are arranged parallel to each other on the light source side and the luminance measurement, and the polarizing films having the polarization axes perpendicular to each other are arranged on the light source side and the luminance measurement. When the luminance Lb in one case is measured and the La / Lb value (contrast ratio) is calculated, a La / Lb value larger than that of the reflective material having a different refractive index in the conventional resin can be obtained. This means that the plastic substrate according to the present invention is a reflective material with little occurrence of polarization extinction effect.

Examples 7-16 and Comparative Examples 1-7

On each plastic film (thickness 50 μm) obtained from Production Examples 1 to 5, a reflective metal film was formed by depositing a reflective metal as shown in Table 3 below, and carbon nanotubes (SWNT, CNI) were used as transparent poly Polyimide varnish dispersed at 0.001 to 1 part by weight based on 100 parts by weight of the mid resin solid content (wherein the polyimide composition uses the polyamic acid composition obtained from Preparation Examples 1 to 5) as a thin film by casting or spraying As a result, a resin layer in which carbon nanotubes were dispersed was formed. In another embodiment, the resin layer was formed by further mixing and dispersing 2 to 100 parts by weight of ITO powder with respect to 100 parts by weight of the polyimide resin solid content in forming the resin layer in which the CNT prepared above was dispersed. Examples 15-16).

Specific types and thickness of the metal film layer, carbon nanotube or ITO powder content and thickness in the resin layer in which the carbon nanotube or ITO powder is dispersed are shown in Table 3 below.

 Plastic film Reflective metal film Conductive Material Dispersion Resin Layer Kinds Thickness (nm) Thickness (um) CNT content * ITO powder content * Example 7 Preparation Example 1 Mg 10 0.4 0.01 - Example 8 Production Example 2 Mg 10 1.2 0.01 - Example 9 Preparation Example 1 Mg 10 2.5 0.01 - Example 10 Preparation Example 5 Mg 50 2.5 0.01 - Example 11 Preparation Example 1 Al 10 0.4 0.01 - Example 12 Production Example 2 Al 10 1.2 0.01 - Example 13 Preparation Example 1 Al 10 2.5 0.01 - Example 14 Preparation Example 5 Al 50 2.5 0.01 - Example 15 Preparation Example 1 Al 10 2.5 0.01 5 Example 16 Preparation Example 1 Al 50 2.5 0.01 25 Comparative Example 1 Preparation Example 1 - - - - - Comparative Example 2 Preparation Example 1 - - 0.04 0.001 - Comparative Example 3 Preparation Example 4 - - 0.2 0.03 - Comparative Example 4 Preparation Example 4 - - 0.2 0.05 - Comparative Example 5 Preparation Example 1 - - 0.4 0.01 - Comparative Example 6 Preparation Example 1 - - 1.2 0.01 - Comparative Example 7 Production Example 2 - - 2.5 0.01 - (Note) * Displayed in parts by weight based on 100 parts by weight of the polyamic acid solid content contained in the varnish

The plastic substrates obtained from Examples 7 to 16 and Comparative Examples 1 to 7 were evaluated as follows, and the results are shown in Table 4.

(1) optical properties

Visible light transmittance was measured on a manufactured plastic substrate using a UV spectrometer (Varian, Cary 100).

From the results in Table 4 below, the comparative example shows a sharp decrease in the transmittance when the CNT content is increased to reduce the surface resistance. As a result, it can be seen that the surface resistance required by the display cannot be achieved in the case of an electrode using only CNT.

Accordingly, when the CNT transparent electrode is formed on the reflective metal film according to the embodiment of the present invention, the required amount of CNT is reduced in comparison with the electrode made of only CNT, and thus has a low surface resistance and high light transmittance of 70% or more. It can be seen that it can be used as a transparent electrode for a display.

In addition, in the case of the transparent electrode using only CNT, the resistance on the electrode surface is significantly influenced by the degree of dispersion of the CNT, which may cause difficulty in the manufacturing process including dispersion, whereas the metal film manufactured according to the embodiment of the present invention In the case of the formed transparent electrode Due to the metal layer, it is possible to perform a certain electrode function basically, this can have the effect of reducing the possibility of not realizing the image due to the loss of the electrode function in the display fabrication.

(2) surface resistance

Surface resistance measurements were measured using a high ohmmeter (Hiresta-UP MCT-HT450 (Mitsuibishi Chemical Corporation) (measurement range: 10 × 10 ⁵ to 10 × 10 ¹⁵ ) and a low ohmmeter (CMT-SR 2000N (Advanced Instrument Teshnology; AIT, 4- Point Probe System, measuring range: 10 10 ^-3 ~ 10 × 10 ⁵ ) was measured 10 times, the average value was obtained.

From the results in the following Table 4, in the case of the transparent electrode according to an embodiment of the present invention, the implementation of lower surface resistance compared to the transparent electrodes (Comparative Examples 5 to 7) having only the CNT layer based on the same amount of CNTs It can be seen that. Therefore, it can be seen that a transparent electrode having excellent transmittance can be realized compared to the transparent electrode of CNT only.

(3) presence of cracks in plastic substrates

In the case of a plastic substrate, in order to form a reflective metal film and use it as an electrode, the thickness of the reflective metal film deposited on the plastic film becomes thick, which causes peeling and cracking of the metal layer due to a difference in flexibility between the plastic substrate and the metal layer when the plastic substrate is bent. It can cause the loss of the function of the electrode. However, in the case of the plastic substrate according to the embodiment of the present invention, the thickness of the reflective metal film may be reduced by introducing a resin layer in which a conductive material is dispersed along with the reflective metal film, and the reflective metal film and the reflective film on the plastic film and the film Since the resin of the resin layer in which the conductive material on the metal film is dispersed can reduce the problem of peeling and cracking of the reflective metal film due to the difference in the dimensional stability generated when bending, the display of the reflective metal film as compared to the single electrode layer of the conventional reflective metal film. And peeling resistance and uniformity against bending of the substrate can be improved.

In this regard, specific evaluation results are not listed in Table 4.

(4) Gas and water barrier properties

Oxygen Permeability (OTR)

Mocon Oxytran 1000 was used to measure the average value 10 times at 23 ° C. and 0% RH according to ASTM D-39859.

Moisture Permeability (WVTR)

Mocon Aquatran Model 1 was used to measure the average value of 10 times at 38 ° C. and 90% RH according to ASTM F-1249.

Since the film itself contains air or moisture, and also has high air permeability and moisture permeability, air or moisture invades the liquid crystal layer or the organic light emitting element layer from outside air or the film, and bubbles are generated. And the organic light emitting device is oxidized, which may reduce the lifespan and deteriorate the display device. As a solution to this, a barrier layer for blocking gas and water may be formed by forming a multilayer of a single layer inorganic material layer or an organic layer / inorganic layer on an inner surface and / or an outer surface of a film used as a substrate. That is, not only the air and moisture of the outside air but also the air and moisture contained in the film itself can be blocked.

However, the reflective metal film included in the plastic substrate of the present invention is formed on the plastic film serving as the substrate to serve as a gas barrier layer as well as an electrode to manufacture the display device. It can be seen from the results of oxygen permeability and moisture permeability of Table 4 that the cost can be reduced and the life can be improved.

Surface Resistance (Ω / Sq) Transmittance (500nm,%) OTR (cc / M ² Day) WVTR (g / M ² Day) Example 7 2.2 x 10 ⁶ 81.2 0.025 0.068 Example 8 1.9 x 10 ⁶ 81.2 0.02 0.054 Example 9 4.2 x 10 ⁵ 83.4 0.01 0.028 Example 10 2.2 x 10 ² 80.1 0.004 0.012 Example 11 5.0 x 10 ⁵ 79.7 0.029 0.059 Example 12 2.0 x 10 ⁵ 81.5 0.022 0.051 Example 13 4.2 x 10 ⁴ 84.4 0.01 0.035 Example 14 6.0 x 10 ¹ 81.1 0.004 0.016 Example 15 3.6 x 10 ² 85.2 0.0096 0.03 Example 16 7.0 x 10 ¹ 85.6 0.0032 0.012 Comparative Example 1 > 10 ¹³ 89.3 57 17.8 Comparative Example 2 3.2 x ^{10 11} 89 20.9 8 Comparative Example 3 2.2 x 10 ³ 75 3.5 5 Comparative Example 4 1.2 x 10 ¹ 54 1.7 1.2 Comparative Example 5 3.0 x ^{10 8} 77.3 0.9 3 Comparative Example 6 1.9 x 10 ⁷ 75.2 0.5 1.1 Comparative Example 7 4.2 x 10 ⁶ 72.2 0.29 0.9

Example  17 to 29 and Comparative example  8 to 14 (Example of Preparation of Transparent Electrode Film)

On each of the plastic films obtained in Production Examples 1 to 5 , an ITO deposition film or an IZO deposition film was formed, and then an ITO deposition layer or an IZO deposition layer was patterned by photolithography and etching to form a stripe-shaped transparent electrode.

Polyimide varnish obtained by dispersing carbon nanotubes (SWNT, CNI Co., Ltd.) at 0.001 to 1% by weight of a transparent polyimide resin solid on an ITO or IZO transparent electrode, wherein the polyimide composition is obtained from Preparation Examples 1 to 5. Polyamic acid composition) was applied as a thin film by casting or spraying to form a resin layer in which carbon nanotubes were dispersed. In another embodiment, 2 to 100 based on 100 parts by weight of the polyimide resin solid content in forming the resin layer in which the CNT prepared above is dispersed. A weight part of ITO powder was further mixed and dispersed to form a resin layer (Examples 26 to 27).

 The thickness of the specific ITO or IXO deposited film, the carbon nanotube content, the ITO powder content and the thickness in the resin layer in which the carbon nanotubes are dispersed are shown in Table 5 below.

 Plastic film ITO deposition film IZO evaporation film Conductive Material Dispersion Resin Layer Thickness (nm) Thickness (nm) Thickness (um) CNT content * ITO powder content * Example 17 Preparation Example 1 50 - 0.4 0.01 ^- Example 18 Production Example 2 50 - 1.2 0.01 ^- Example 19 Preparation Example 1 50 - 2.5 0.01 ^- Example 20 Preparation Example 5 100 - 0.4 0.02 ^- Example 21 Preparation Example 1 100 - 1.2 0.02 ^- Example 22 Production Example 2 100 - 2.5 0.02 ^- Example 23 Preparation Example 1 150 - 0.4 0.05 ^- Example 24 Preparation Example 5 150 - 1.2 0.05 ^- Example 25 Preparation Example 1 150 - 2.5 0.05 ^- Example 26 Preparation Example 1 50 - 2.5 0.01 5 Example 27 Preparation Example 1 50 - 2.5 0.01 25 Example 28 Preparation Example 1 - 100 2.5 0.01 - Example 29 Preparation Example 1 - 150 2.5 0.01 - Comparative Example 8 Production Example 2 50 - - - ^- Comparative Example 9 Production Example 3 100 - - - ^- Comparative Example 10 Preparation Example 1 150 - - - ^- Comparative Example 11 Preparation Example 1 200 - - - ^- Comparative Example 12 Preparation Example 1 300 - - - ^- Comparative Example 13 Preparation Example 1 - - - - 25 Comparative Example 14 Preparation Example 1 - 150 - - - (Note) * Displayed in parts by weight based on 100 parts by weight of the polyamic acid solid content contained in the varnish

Experimental Example 2

The transparent electrode films obtained from Examples 17 to 29 and Comparative Examples 8 to 14 were evaluated as follows, and the results are shown in Table 6 below.

(1) optical properties

The visible light transmittance of the prepared transparent electrode film was measured using a UV spectrometer (Varian, Cary 100).

In the results of Table 6, as the deposition thickness of the ITO or IZO deposition layer becomes thicker, the surface resistance decreases and the transmittance increases. However, if the thickness of the ITO layer (or IZO layer) becomes thicker than 200-300 nm, bending the electrode film may cause peeling between the ITO layer (or IZO layer) and the plastic film and cracking of the ITO layer (or IZO layer). In the case of the electrode whose performance is impaired and the ITO is thick, the banding itself is difficult or the flexibility of the substrate is extremely small, thereby reducing the flexibility, which is one of the objects of the present invention.

Accordingly, when the conductive material dispersion resin layer is formed on the ITO layer (or IZO layer) according to the embodiment of the present invention, the ITO layer (or the ITO layer required for realizing the same surface resistance as compared to the transparent electrode film having only the ITO layer (or IZO layer)) IZO layer) can be reduced, and the amount of conductive material in the conductive material dispersion resin layer required at this time can also reach the surface resistance to be realized in a very small amount due to the presence of the ITO layer (or IZO layer). Inhibition of the transmittance due to the dispersion resin layer is extremely small, and since the conductive material dispersion resin layer is also a highly transparent colorless resin, it may exhibit a similar level of transmittance as compared to a thick film composed of only an ITO layer (or IZO layer). In addition, the transparent electrode film including the conductive material dispersion resin layer according to the embodiment of the present invention as described below also enables the correction function for the peeling and cracking of the ITO layer (or IZO layer).

(2) surface resistance

Surface resistance measurements include high resistance meter (Hiresta-UP MCT-HT450 (Mitsubishi Chemical Corporation), measuring range: 10 × 10 ⁵ to 10 × 10 ¹⁵ ) and low resistance meter (CMT-SR 2000N (Advanced Instrument Technology; AIT, 4- Point Probe System), measuring range: 10 × 10 ⁻³ to 10 × 10 ⁵ ), and measured 10 times to obtain an average value.

As shown in Table 6, it can be seen that the transparent electrode according to the embodiment of the present invention can realize lower surface resistance than the CNT-only transparent electrode based on the same amount of CNT. Therefore, it can be seen that a transparent electrode having excellent transmittance can be realized compared to the transparent electrode of CNT only.

(3) ITO Banding

The results in Table 4 show that as the deposition thickness of ITO becomes thicker, the surface resistance decreases and the transmittance increases. However, when the electrode film is bent due to the increase in the thickness of the ITO layer, the ITO layer may be cracked, thereby degrading its performance, and in the case of the electrode having a high ITO, banding may be difficult or the flexibility of the substrate may be extremely small, thereby reducing the flexibility. However, in the case of including the resin layer in which the conductive material is dispersed on the ITO deposition layer (or the IZO deposition layer) according to one embodiment of the present invention, the thickness of the ITO layer to achieve a relatively required surface resistance and light transmittance is reduced. Compared to the electrode film of the conventional structure, the flexibility of the transparent electrode is increased, and the resin of the resin layer in which the conductive material is dispersed, the ITO layer (or IZO layer) is protected by a flexible polymer resin on the upper and lower sides, compared to the conventional ITO electrode. It can be seen that the incidence of cracking due to bending decreases.

As described above, according to one embodiment of the present invention, the electrical conductivity is excellent, and even though the thickness is thin, the permeability can be excellent, compared to the conventional transparent electrode of CNT or ITO, low cost material A thin film and a transparent electrode having excellent permeability can be obtained.

Also, since Ag, Mg, and Ba are metals, it is possible to easily make ohmic contact at the junctions with TFT and other devices when manufacturing active matrix panels, and Ag having high work function when manufacturing organic EL devices. the transparent electrode includes the use as a Anode and a transparent electrode comprising a Ca or Mg has an advantage that can be used to Cathod e.

Surface Resistance (Ω / Sq) Transmittance (500nm,%) OTR (cc / M ² Day) WVTR (g / M ² Day) Example 17 7.0 x 10 ² 88.2 0.026 0.06 Example 18 4.7 x 10 ² 87.9 0.024 0.051 Example 19 2.8 x 10 ² 87.7 0.018 0.047 Example 20 5.0 x 10 ² 86.9 0.0085 0.035 Example 21 ^2.0 x 10 ² 86.2 0.0077 0.03 Example 22 6.0 x 10 ¹ 85.8 0.0068 0.027 Example 23 5.0 x 10 ¹ 86.3 0.006 0.022 Example 24 3.0 x 10 ¹ 85.8 0.0045 0.016 Example 25 2.3 x 10 ¹ 85.1 0.004 0.012 Example 26 4.5 x 10 ¹ 88.2 0.0038 0.011 Example 27 2.2 x 10 ¹ 88.2 0.0015 0.006 Example 28 1.5 x 10 ² 86.4 0.004 0.013 Example 29 5.2 x 10 ¹ 87.3 0.0017 0.007 Comparative Example 8 2.0 x 10 ³ 87.2 0.03 0.062 Comparative Example 9 7.0 x 10 ² 86.9 0.01 0.041 Comparative Example 10 5.0 x 10 ² 87.8 0.0069 0.027 Comparative Example 11 4.0 x 10 ¹ 87.5 0.004 0.015 Comparative Example 12 6.0 x 10 ⁰ 86.7 0.003 0.011 Comparative Example 13 4.0 x 10 ² 87.1 0.04 0.15 Comparative Example 14 8.0x10 ² 87.9 0.0045 0.019

1 is a cross-sectional view of a flat panel display device, (a) is a liquid crystal display device element, (b) to (c) is a cross-sectional view of an organic EL device.

2 is a cross-sectional view of a plastic substrate according to one embodiment of the present invention.

3 to 7 are cross-sectional views showing various embodiments of the plastic substrate of the present invention.

8 illustrates an example of a luminance measuring method for measuring reflectivity of a plastic substrate manufactured according to the present invention.

<Description of the symbols for the main parts of the drawings>

1 Glass substrate 11 ITO electrode

100: plastic substrate, 101: inorganic layer

102: UC (chemical layer), 103: protective layer (planarization layer)

110: reflective metal film, 112: metal electrode

113: reflective electrode,

120: resin layer in which conductive material is dispersed 130: alignment layer

150: liquid crystal 160: organic light emitting layer

Claims (29)

Plastic film; And A plastic substrate comprising a reflective metal film. The method of claim 1, wherein the reflective metal film is aluminum, titanium, silver, platinum, magnesium, Single or an alloy thereof selected from tantalum and palladium, or A metal film comprising ITO or IZO, wherein the plastic substrate is a single layer or a multilayer of the same or different materials. The plastic substrate according to claim 1 or 2, wherein the reflective metal film is aluminum or an alloy thereof, or magnesium or an alloy thereof. The method of claim 1, wherein the reflective metal film comprises: a lower metal film made of aluminum or an alloy thereof, or magnesium or an alloy thereof; And an upper metal film made of ITO or IZO. The plastic substrate according to claim 1, wherein the reflective metal film has a thickness of 10 to 1000 nm. 6. The plastic substrate according to claim 5, wherein the reflective metal film has a thickness of 50 to 300 nm. The plastic substrate according to claim 1, wherein the plastic film is a polyimide film. The method according to claim 1, wherein the plastic film has a polyolefin having an average coefficient of linear expansion (CTE) of 50.0 ppm / 占 폚 or less and a yellowness of 15 or less, measured by a thermomechanical method based on a film thickness of 50 to 100 μm. It is a mid film, The plastic substrate characterized by the above-mentioned. The plastic film has an L value of 90 or more, a value of 5 or less, and b value of 5 or less when the color coordinate is measured by UV spectrophotometer based on the film thickness of 50 to 100 µm. It is a polyimide film, The plastic substrate characterized by the above-mentioned. The plastic substrate of claim 1, further comprising a protective layer formed on the reflective metal film. The polyimide of claim 10, wherein the protective layer has an average linear expansion coefficient (CTE) of 50.0 ppm / ° C. or less and a yellow chromaticity of 15 or less, measured in a range of 50 to 250 ° C. by thermomechanical analysis based on a thickness of 50 to 100 μm. It is a layer, a plastic substrate. The plastic film according to claim 10 or 11, wherein the protective layer is a polyimide layer having an average transmittance of 85% or more at 380 to 780 nm when the transmittance is measured by a UV spectrophotometer based on a thickness of 50 to 100 µm. Board. The protective layer is a polyimide layer according to claim 10 or 11, having a transmittance of 88% or more at 550 nm and a transmittance of 70% or more at 420 nm when the transmittance is measured by a UV spectrophotometer based on a thickness of 50 to 100 μm. Plastic substrate, characterized in that. The plastic substrate of claim 1, further comprising a resin layer in which a conductive material is dispersed on the reflective metal film. The plastic substrate of claim 10, further comprising a resin layer on which the conductive material is dispersed. 16. The plastic substrate of claim 14 or 15, wherein the conductive material is carbon nanotubes or ITO powder. The plastic substrate according to claim 14, wherein the resin layer in which the conductive material is dispersed is formed from a polyimide varnish in which the conductive material is dispersed. 18. The plastic substrate according to claim 17, wherein the resin layer in which the conductive material is dispersed is formed from a varnish containing 0.001 to 1 parts by weight of carbon nanotubes based on 100 parts by weight of a polyimide resin solid content. 18. The plastic substrate according to claim 17, wherein the resin layer in which the conductive material is dispersed is formed from a varnish containing 2 to 100 parts by weight of ITO powder with respect to 100 parts by weight of the polyimide resin solid content. 20. The plastic substrate according to claim 16 or 19, wherein the ITO powder contains 80 to 95% by weight of indium oxide and 5 to 20 parts by weight of tin oxide. The plastic substrate according to claim 14 or 15, wherein the resin layer in which the conductive material is dispersed has a thickness of 10 nm to 25 um. The plastic substrate of claim 1, further comprising a chemical resistant layer formed on at least one surface of the plastic film. The plastic substrate according to claim 22, wherein the chemical resistant layer is at least one resin layer selected from acrylate-based, epoxy-based, and polyimide-based resins. The plastic substrate of claim 1, further comprising an inorganic layer formed under the plastic film. The plastic substrate of claim 1, further comprising an inorganic layer formed under the reflective metal film. The plastic substrate according to claim 1, wherein the plastic substrate is a lower substrate of the transmissive electronic paper and the display device. An electronic paper device comprising a plastic substrate including a plastic film and a reflective metal film as a lower substrate. A liquid crystal display comprising a plastic substrate including a plastic film and a reflective metal film as a lower substrate. Comprising a plastic substrate comprising a plastic film and a reflective metal film as a lower substrate OLED device.

Images