KR102361783B1 - Embedded transparent electrode substrate and method for manufacturing thereof - Google Patents

Abstract

A transparent electrode substrate according to an exemplary embodiment of the present application includes a transparent substrate; an adhesive layer provided on the transparent substrate and including a groove pattern; and a metal foil pattern provided inside the groove pattern of the adhesive layer, wherein the step between the upper surface of the region in which the groove pattern of the adhesive layer is not provided and the upper surface of the metal foil pattern is not provided with the groove pattern of the adhesive layer. It is characterized in that the upper surface of the is 1㎛ to 50㎛ higher.

Description

EMBEDDED TRANSPARENT ELECTRODE SUBSTRATE AND METHOD FOR MANUFACTURING THEREOF

The present application relates to a buried type transparent electrode substrate and a method for manufacturing the same.

Recently, through the convergence of cutting-edge ICT technology and LED technology, Korea is providing information and attractions to city residents by producing not only colorful signboards but also various landscape lighting in parks and downtown areas. In particular, the transparent LED display using the ITO transparent electrode material has the advantage of applying an LED between the glass and the glass or attaching a transparent film to which the LED is applied to one side of the glass, so that the wire is not visible, so it can be produced in a luxurious way. For this reason, it is being used for interior decoration of hotels and department stores, and its importance is growing in the realization of the media façade of the exterior wall of the building.

The demand for transparent electrodes used for touch screens, etc., which are transparent yet flow electricity, has exploded with the spread of smart devices. Among them, the most used transparent electrode is Indium Tin Oxide (ITO), an oxide of indium and tin. However, indium, the main raw material of ITO transparent electrode material, is produced only in some countries, such as China, with few reserves worldwide, and the production cost is high. In addition, there is a disadvantage that the displayed LED light is not constant because the resistance value is not uniformly applied. For this reason, there is a limit to using ITO-based transparent LED as a high-performance, low-cost transparent electrode material.

It is true that ITO has been used as a transparent electrode material with the largest proportion, but research and technology development using new materials is continuously being made due to limitations such as economic feasibility and limited performance. Transparent electrode materials that are attracting attention as next-generation new materials include metal mesh, nanowire, carbon nanotube (CNT), conductive polymer, and graphene. Among them, metal mesh is a new material that accounts for 85% of the materials that have replaced ITO, and has low cost and high conductivity, so the market is expanding in terms of its utilization.

The transparent LED display using the metal mesh is easier to maintain than the existing ITO transparent display, and it is economical by reducing the manufacturing cost as well as saving resources and reducing environmental pollution significantly. In addition, it can be applied to a variety of uses, and as a new transparent electrode material, it has the potential to be applied and utilized in various products.

Korean Patent Publication No. 10-2015-0033169

An object of the present application is to provide a buried transparent electrode substrate and a method for manufacturing the same.

An exemplary embodiment of the present application is,

transparent substrate;

an adhesive layer provided on the transparent substrate and including a groove pattern; and

It includes a metal foil pattern provided inside the groove pattern of the adhesive layer,

The step difference between the upper surface of the region where the groove pattern of the adhesive layer is not provided and the upper surface of the metal foil pattern is 1 µm to 50 µm higher than the upper surface of the region where the groove pattern of the adhesive layer is not provided. A substrate is provided.

In addition, another embodiment of the present application is,

forming a structure including a transparent substrate, an adhesive layer provided on the transparent substrate, and a metal foil provided on the adhesive layer;

laminating a dry film resist (DFR) on the metal foil;

patterning the metal foil and the dry film resist to form a metal foil pattern and a dry film resist pattern;

performing a thermal bonding process at a temperature of 70° C. to 100° C. to embed the metal foil pattern and the dry film resist pattern into the adhesive layer; and

removing the dry film resist pattern and completely curing the adhesive layer

It provides a method of manufacturing a buried transparent electrode substrate comprising a.

According to an exemplary embodiment of the present application, since the metal foil pattern is formed using an inexpensive metal foil, the cost of raw materials can be reduced when manufacturing the transparent electrode substrate. In particular, according to an exemplary embodiment of the present application, after forming a metal foil pattern and a dry film resist pattern on an adhesive layer, performing a thermal bonding process at a temperature of 70° C. to 100° C., and then removing the dry film resist pattern, A buried transparent electrode substrate in which the metal foil pattern is embedded into the adhesive layer may be manufactured.

In addition, according to an exemplary embodiment of the present application, it is possible to prevent an increase in haze of the transparent electrode substrate according to the roughness of the surface of the metal foil by heat-treating it at a temperature of 70°C to 100°C after forming the metal foil pattern on the adhesive layer. .

In addition, according to an exemplary embodiment of the present application, the step between the upper surface of the region in which the groove pattern of the adhesive layer is not provided and the upper surface of the metal foil pattern is 1, the upper surface of the region in which the groove pattern of the adhesive layer is not provided. μm to 50 μm higher configuration. Accordingly, it is possible to prevent the solder from spreading to the adjacent metal electrode during a solder reflow process for mounting the LED on the electrode substrate, and short-circuit defects can be prevented.

In addition, when the solder spreads and connects to the adjacent metal electrode, short circuit failure occurs, and even when the solder further spreads out of the metal pad and does not spread to the adjacent metal electrode, the solder leaving the metal pad becomes a solder ball shape and is not deposited on the substrate. Otherwise, it may be lost and cause a short circuit in other metal electrodes. Therefore, according to an exemplary embodiment of the present application, solder reflow may be performed only in a limited specific area such as a metal pad.

1 is a diagram schematically illustrating a buried type transparent electrode substrate according to an exemplary embodiment of the present application.
2 is a diagram schematically illustrating a method of manufacturing a buried transparent electrode substrate according to an exemplary embodiment of the present application.
3 is a view schematically showing a conventional transparent electrode substrate.
4 to 8 are views showing a buried transparent electrode substrate according to Example 1 of the present application, respectively.
9 to 11 are diagrams illustrating solder reflow shapes of electrode substrates according to Example 1, Comparative Example 1, and Comparative Example 2 of the present application, respectively.
12 and 13 are diagrams schematically illustrating electrode substrates according to Comparative Examples 1 and 2 of the present application, respectively.

Hereinafter, the present application will be described in detail.

In the present application, "transparent" means having a transmittance characteristic of about 80% or more in the visible ray region (400 to 700 nm).

In the case of a transparent electrode substrate applied to a transparent LED display having a metal wire on the transparent substrate, transmittance of 70% or more and sheet resistance of 0.5 ohm/sq or less must be secured. In order to secure the transmittance and sheet resistance characteristics, the copper deposition layer having a low resistivity layer should have a thickness of 1 μm or more. A copper deposition layer of 1 μm or larger can be formed on the upper part of the transparent substrate by using sputtering, evaporation, plating, etc., but in this case, expensive deposition costs occur, adhesion of the copper deposition layer is reduced, and the lower part is transparent during the deposition process. Damage to the substrate may occur.

In addition, when a low-cost copper foil and a transparent substrate are laminated using an adhesive, the manufacturing cost can be greatly reduced and adhesion can be improved, but the surface roughness of the copper foil is transferred to the adhesive surface, thereby increasing the haze of the opening. problem arises.

In addition, in order to manufacture a buried electrode having excellent surface flatness, a resin layer is additionally applied on a transparent substrate provided with an electrode pattern, and then the residual resin layer present on the electrode is removed, or the electrode is placed on a release substrate. A method of transferring an electrode to a resin layer by coating and curing a resin layer on top of the pattern after forming the pattern can be used, but in this case, the process is complicated and manufacturing cost is increased.

In addition, if the SMT (surface-mount technology) solder screen printing for mounting the LED on the transparent electrode substrate is biased and printed, the solder is spread to the adjacent metal electrode during the reflow process, resulting in a short defects may occur. The conventional transparent electrode substrate as described above is schematically shown in FIG. 3 . Solder paste screen printing tolerance is at least 100㎛ or more on average. In order to prevent the above defects, when the separation distance between the adjacent metal electrodes is greater than or equal to a certain level, the area and position of the pad portion and the wiring portion may be limited during design.

Accordingly, in the present application, in order to secure price competitiveness, an ultra-low-priced metal foil is used as a metal layer, the haze of the transparent electrode substrate can be improved, and a buried type transparent electrode substrate capable of preventing short circuit defects during solder reflow, and An object of the present invention is to provide a manufacturing method thereof.

An embedded transparent electrode substrate according to an exemplary embodiment of the present application includes a transparent substrate; an adhesive layer provided on the transparent substrate and including a groove pattern; and a metal foil pattern provided inside the groove pattern of the adhesive layer, wherein the step between the upper surface of the region in which the groove pattern of the adhesive layer is not provided and the upper surface of the metal foil pattern is not provided with the groove pattern of the adhesive layer. It is characterized in that the upper surface of the is 1㎛ to 50㎛ higher.

In an exemplary embodiment of the present application, the transparent substrate may be a glass substrate or a transparent plastic substrate excellent in transparency, surface smoothness, handling and waterproofing properties, but is not limited thereto, and if it is a transparent substrate commonly used in electronic devices not limited Specifically, as the transparent substrate, glass; urethane resin; polyimide resin; polyester resin; (meth)acrylate-based polymer resin; It may be made of a polyolefin-based resin such as polyethylene or polypropylene. In addition, the transparent substrate may be a film having a visible light transmittance of 80% or more, such as polyethylene terephthalate (PET), cyclic olefin polymer (COP), polyethylene naphthalate (PEN), polyethersulfone (PES), polycarbonate (PC), or acetyl celluloid. The thickness of the transparent substrate may be 25 μm to 250 μm, but is not limited thereto.

In the exemplary embodiment of the present application, the metal foil pattern may use a material known in the art, and more specifically, may include a copper foil (Cu Foil) pattern or an aluminum foil (Al Foil) pattern, but limited thereto it is not going to be The metal foil pattern may have a thickness of 2 μm to 20 μm. The thickness of the metal foil pattern can be measured with a micrometer or a thickness gauge.

In the exemplary embodiment of the present application, the adhesive layer may have a refractive index of 1.45 to 1.55, and may have fluidity at a temperature of 70° C. or higher. In addition, the adhesive layer may include a thermosetting adhesive composition or a UV curing adhesive composition.

More specifically, the adhesive layer may include a silane-modified epoxy resin, a bisphenol A-type phenoxy resin, an initiator, and a silane coupling agent, but is not limited thereto.

The adhesive layer may be formed in a thickness range of 5 μm to 30 μm by using the above-described adhesive composition, comma coating, slot die coating, or the like, but is not limited thereto.

In the present application, the refractive index is a prism coupler (Prism Coupler; equipment example - Metricon's 2010/M), ellipsometer (　 equipment example - Horriba Scientific's UVISEL), Abbe Refractometer (equipment example - Kruss Corporation) AR4) can be measured. For example, a refractive index may be calculated by measuring a change in the amount of light reflected from the coating layer using a prism coupler. More specifically, a material for which a refractive index is to be measured is coated on glass or other substrate with a known refractive index by a method such as spin coating to a thickness of several μm, and then the coated sample is brought into contact with a prism. After that, when the laser is incident on the prism, most of it is totally reflected, but when a specific incident angle and conditions are satisfied, an evanescent field is generated at the interface and the light is coupled. When coupling occurs and the angle at which the intensity of light detected by the detector sharply decreases is measured, the prism coupler can automatically calculate the refractive index of the coating layer from the parameters related to the polarization mode of the light and the refractive index of the prism and the substrate.

The metal foil pattern may be manufactured from a metal foil including at least one surface of a matt surface having a relatively high ten-point average roughness (Rz). At this time, the mat surface of the metal foil faces the transparent substrate.

The metal foil pattern may include two or more types of metal foil patterns having different line widths. In addition, the metal foil pattern may include two types of metal foil patterns having different line widths, one type of metal foil pattern may have a line width of 3 μm to 30 μm, and the line width of the other type of metal foil pattern may be 50 μm or more. The metal foil pattern having a line width of 3 μm to 30 μm may serve as an electrode pattern, and the metal foil pattern having a line width of 50 μm or more may serve as an electrode pad pattern for connecting external terminals. That is, the metal foil pattern may include an electrode pattern and an electrode pad part pattern.

The line width of the electrode pattern may be 3 μm to 30 μm, 3 μm to 20 μm, and 3 μm to 10 μm, but is not limited thereto. In addition, the line width of the electrode pad part pattern may be 50 μm or more, and may be 50 μm to 1,000 μm, but is not limited thereto.

In the exemplary embodiment of the present application, the ten-point average roughness (Rz) of the lower surface of the metal foil pattern facing the transparent substrate is greater than 0.5 μm, and the ten-point average of the upper surface of the region where the groove pattern of the adhesive layer is not provided The roughness Rz may be 0.1 μm or less. In addition, the ten-point average roughness (Rz) of the lower surface of the metal foil pattern facing the transparent substrate may be greater than 0.5 μm and less than 3 μm. In addition, the ten-point average roughness Rz of the upper surface of the region where the groove pattern of the adhesive layer is not provided may be 0 to 0.1 μm. When the ten-point average roughness (Rz) of the lower surface of the metal foil pattern facing the transparent substrate is 0.5 μm or less, the metal foil has a characteristic high reflectance due to low concavities and convexities. Therefore, since it is difficult to lower the reflectance of the transparent electrode substrate manufactured therefrom, there is a disadvantage that the pattern is easily recognized by the eye due to the high reflectance. In addition, when the ten-point average roughness (Rz) of the lower surface of the metal foil pattern facing the transparent substrate is 0.5 μm or less, the adhesion between the metal foil and the adhesive layer is lowered and the metal foil pattern is formed during the process of forming the metal foil pattern (photo process) as the adhesive layer A problem of detachment may occur.

That is, when an inexpensive metal foil is laminated after providing an adhesive layer on a transparent substrate, the surface roughness of the metal foil is transferred to the surface of the adhesive layer, thereby increasing haze of the final product may occur. Accordingly, according to an exemplary embodiment of the present application, it is possible to prevent an increase in haze of the transparent electrode substrate according to the roughness of the surface of the metal foil by forming a metal foil pattern on the adhesive layer and then heat-treating it at a temperature of 70°C to 100°C.

In the present application, the ten-point average roughness (Rz) value may mean a difference between an average height of five highest peaks and an average depth of five deepest valleys in a cross-sectional curve. The Rz may be measured with a Mitutoyo SJ301 measuring device.

In the exemplary embodiment of the present application, the step difference between the upper surface of the region in which the groove pattern of the adhesive layer is not provided and the upper surface of the metal foil pattern is 1 μm to the upper surface of the region in which the groove pattern of the adhesive layer is not provided. It is characterized in that it is 50 μm higher. Accordingly, it is possible to prevent the solder from spreading to the adjacent metal electrode during a solder reflow process for mounting the LED on the electrode substrate, and short-circuit defects can be prevented.

The step difference between the upper surface of the region where the groove pattern of the adhesive layer is not provided and the upper surface of the metal foil pattern may be measured using a method known in the art. For example, a method of observing and measuring the SEM cross section, a method of measuring with a non-contact surface profiler (Optical Profiler), a method of measuring with a stylus type surface step measuring device (Alpha Step or Surfacer Profiler), etc. may be used.

In addition, a haze of a region in which the metal foil pattern of the buried transparent electrode substrate is not provided may be 5% or less.

A buried transparent electrode substrate according to an exemplary embodiment of the present application is schematically shown in FIG. 1 below.

1, the buried type transparent electrode substrate according to an exemplary embodiment of the present application includes a transparent substrate 10; an adhesive layer 20 provided on the transparent substrate 10 and including a groove pattern; and a metal foil pattern 30 provided inside the groove pattern of the adhesive layer 20, wherein the upper surface 40 of the region where the groove pattern of the adhesive layer 20 is not provided and the upper surface 50 of the metal foil pattern ) is characterized in that the upper surface 40 of the region where the groove pattern of the adhesive layer 20 is not provided is 1 μm to 50 μm higher.

In addition, the method for manufacturing a buried type transparent electrode substrate according to an exemplary embodiment of the present application includes forming a structure including a transparent substrate, an adhesive layer provided on the transparent substrate, and a metal foil provided on the adhesive layer ; laminating a dry film resist (DFR) on the metal foil; patterning the metal foil and the dry film resist to form a metal foil pattern and a dry film resist pattern; performing a thermal bonding process at a temperature of 70° C. to 100° C. to embed the metal foil pattern and the dry film resist pattern into the adhesive layer; and removing the dry film resist pattern and completely curing the adhesive layer.

A method of manufacturing an embedded transparent electrode substrate according to an exemplary embodiment of the present application includes forming a structure including a transparent substrate, an adhesive layer provided on the transparent substrate, and a metal foil provided on the adhesive layer.

Forming the structure may include: forming an adhesive layer on a metal foil, and forming a transparent substrate on the adhesive layer; Alternatively, the method may include forming an adhesive layer on a transparent substrate and forming a metal foil on the adhesive layer.

The adhesive layer may be formed in a thickness range of 5 to 30 μm by using the above-described adhesive composition, comma coating, slot die coating, or the like, but is not limited thereto.

A method of manufacturing a buried transparent electrode substrate according to an exemplary embodiment of the present application includes laminating a dry film resist on the metal foil.

The dry film resist may include materials known in the art. More specifically, the dry film resist may include a monofunctional monomer selected from the group consisting of methacrylate and its derivatives, acrylate and its derivatives, and methacrylate of methacryyloxyethyl acid phosphate and phthalic acid derivatives; Dimethacrylate and its derivatives, diacrylate and its derivatives, trimethacrylate and its derivatives, tetramethacrylate and its derivatives, triacrylate and its derivatives, and tetraacrylate and its derivatives functional monomers; and a photopolymerizable monomer selected from mixtures thereof. In general, the composition of the photosensitive layer of the dry film resist includes a photopolymerization monomer (polyfunctional monomer) that photopolymerizes by light, a photopolymerization initiator that induces radicals or radicals by light to cause photopolymerization, mechanical strength and tendability of the photopolymerization composition, and It may contain additives such as a binder polymer that imparts adhesiveness, and a dye, a stabilizer, an adhesion promoter, and a thermal polymerization inhibitor.

The method of manufacturing a buried transparent electrode substrate according to an exemplary embodiment of the present application includes forming a metal foil pattern and a dry film resist pattern by patterning the metal foil and the dry film resist.

A method of forming the metal foil pattern and the dry film resist pattern may use a method known in the art, for example, a photolithography process may be used. More specifically, the method of forming the metal foil pattern and the dry film resist pattern may include etching the metal foil after forming the dry film resist pattern on the metal foil, but is not limited thereto.

The method for manufacturing a buried transparent electrode substrate according to an exemplary embodiment of the present application includes performing a thermal bonding process at a temperature of 70° C. to 100° C., and embedding the metal foil pattern and the dry film resist pattern into the adhesive layer. do.

By performing the thermal bonding process at a temperature of 70° C. to 100° C., the metal foil pattern and the dry film resist pattern may be embedded into the adhesive layer. More specifically, the step of performing the thermal bonding process at a temperature of 70 ° C. to 100 ° C. by applying pressure to the upper portions of the metal foil pattern and the dry film resist pattern with a hot plate or a hot roll. , the metal foil pattern and the film resist pattern may be embedded in the adhesive layer.

In addition, the ten-point average roughness (Rz) of the surface of the adhesive layer before the thermal bonding process may be greater than 0.5 µm, and the ten-point average roughness (Rz) of the surface of the adhesive layer after the thermal bonding process may be 0.1 µm or less. In addition, the ten-point average roughness (Rz) of the surface of the adhesive layer before the thermal bonding process may be greater than 0.5 μm and less than 3 μm. In addition, the ten-point average roughness (Rz) of the surface of the adhesive layer after the thermal bonding process may be 0 to 0.1 μm. When the ten-point average roughness (Rz) of the surface of the adhesive layer before the thermal bonding process is 0.5 μm or less, it has a high reflectance characteristic of the metal foil due to low unevenness. Therefore, since it is difficult to lower the reflectance of the transparent electrode substrate manufactured therefrom, there is a disadvantage that the pattern is easily recognized by the eye due to the high reflectance. In addition, when the ten-point average roughness (Rz) of the surface of the adhesive layer before the thermal bonding process is 0.5 μm or less, the adhesion between the metal foil and the adhesive layer is lowered, and the metal foil pattern is detached from the adhesive layer during the process of forming the metal foil pattern (photo process) problems may arise.

That is, when an inexpensive metal foil is laminated after providing an adhesive layer on a transparent substrate, the surface roughness of the metal foil is transferred to the surface of the adhesive layer, thereby increasing haze of the final product may occur. Accordingly, according to an exemplary embodiment of the present application, after forming a metal foil pattern on the adhesive layer, a thermal bonding process is performed at a temperature of 70° C. to 100° C., thereby preventing an increase in haze of the transparent electrode substrate according to the roughness of the surface of the metal foil. can do.

The method of manufacturing a buried transparent electrode substrate according to an exemplary embodiment of the present application includes removing the dry film resist pattern and completely curing the adhesive layer. The adhesive layer may include a thermosetting adhesive composition or a UV curable adhesive composition, and the step of completely curing the adhesive layer may include thermosetting or UV curing the adhesive layer at a temperature of 120° C. or higher.

As a method of removing the dry film resist pattern, a method known in the art may be used, and more specifically, the dry film resist pattern may be removed by a spray process or an immersion process using an alkali stripper.

In addition, a method of manufacturing a buried transparent electrode substrate according to an exemplary embodiment of the present application is schematically shown in FIG. 2 below.

As shown in FIG. 2 below, in the method of manufacturing an embedded transparent electrode substrate according to an exemplary embodiment of the present application, the transparent substrate 10, the adhesive layer 20 provided on the transparent substrate 10, and the adhesive layer provided on the Forming a structure comprising a metal foil (metal foil) (60); Laminating a dry film resist (dry film resist, DFR) (70) on the metal foil (60); patterning the metal foil 60 and the dry film resist 70 to form a metal foil pattern 30 and a dry film resist pattern 80; embedding the metal foil pattern 30 and the dry film resist pattern 80 into the adhesive layer 20 by performing a thermal bonding process at a temperature of 70° C. to 100° C.; and removing the dry film resist pattern 80 and completely curing the adhesive layer 20 .

The buried transparent electrode substrate according to the exemplary embodiment of the present application may be applied as a transparent electrode of an electronic device.

The electronic device may be a heating film, a transparent LED display, a touch panel, a solar cell, or a transistor. The heating film, transparent LED display, touch panel, solar cell, or transistor may be those generally known in the art, and the electrode may be used as a transparent electrode substrate according to an exemplary embodiment of the present application.

Hereinafter, the embodiments described in the present specification are illustrated by way of Examples. However, it is not intended that the scope of the above embodiments be limited by the following examples.

< Example >

< Example 1>

A UV curable adhesive was applied on a PET film with a thickness of 250 μm using a comma coater and then dried with hot air at 100° C. for 5 minutes to form an adhesive layer having a refractive index of 1.45 to 1.55 and a thickness of 30 μm. At this time, the UV curable adhesive is, silane-modified epoxy resin KSR-277HMC70 (Kukdo Chemical) 33% by weight, silane-modified epoxy resin KSR-177 (Kukdo Chemical) 35% by weight, bisphenol A phenoxy resin YP-50E (Kukdo Chemical) Chemical) 30% by weight, cationic initiator Igacure290 (BASF) 1% by weight, and silane coupling agent KBM-403 (Shinetsu) 1% by weight.

The PET film provided with the transparent adhesive layer and the copper foil having a thickness of 8 μm were hot roll-laminated at 100° C. and 1.3 mpm (meter per minute). At this time, the transparent adhesive layer and the matt surface of the copper foil were brought into contact, the ten-point average roughness (Rz) of the matt surface of the copper foil was 1.63 µm to 2.54 µm, and the ten-point average roughness (Rz) of the shiny surface of the copper foil was 0.1 µm. .

After laminating DFR (Dry Film Resist) on the copper foil side of the copper foil laminated film, a Hexagonal DFR pattern having a line width of 20 μm was formed through exposure and development processes.

A hexagonal copper foil pattern was formed by removing the exposed copper foil using a ferric chloride-based copper etchant. At this time, the haze of the region where the copper foil pattern was not provided was 86.7%. The film on which the DFR pattern and the copper foil pattern were formed is shown in FIG. 4 below.

After the copper foil pattern and the DFR pattern are embedded in the adhesive layer by applying pressure to the upper portion of the copper foil pattern and the DFR pattern with a hot plate while the copper foil pattern film is heat treated at 100° C. for 5 minutes, an alkali stripper is used Thus, the DFR pattern was peeled off by a spray process. The film in which the copper foil pattern and the DFR pattern were embedded into the adhesive layer was shown in FIG. 5, and the film after the DFR pattern was peeled off is shown in FIG. 6 below.

Thereafter, the adhesive layer was completely cured by irradiating UV with an exposure amount of 2 J/cm ² from the opposite side of the surface on which the copper foil pattern was provided. At this time, the haze of the region where the copper foil pattern was not provided was 3.44%. In addition, the step difference between the upper surface of the region where the groove pattern of the adhesive layer is not provided and the upper surface of the metal foil pattern was 15 μm.

The surface shape of the adhesive layer before embedding the copper foil pattern and the DFR pattern into the adhesive layer is shown in FIG. 7, and the surface shape of the adhesive layer after embedding the copper foil pattern and the DFR pattern into the adhesive layer is shown in FIG. 7 and 8, it can be seen that the high roughness of the adhesive layer reflected by the surface of the copper foil is planarized after the thermal bonding process.

< comparative example 1>

In Example 1, a copper foil pattern was formed on a PET film without forming an adhesive layer, and a thermal bonding process was not performed. The structure of the electrode substrate of Comparative Example 1 is shown in FIG. 12 below.

< comparative example 2>

After forming the copper foil pattern in Example 1, the DFR pattern was peeled off. Thereafter, a thermal bonding process was performed to embed only the copper foil pattern into the adhesive layer. The structure of the electrode substrate of Comparative Example 2 is shown in FIG. 13 below.

At this time, the step difference between the upper surface of the region where the groove portion pattern of the adhesive layer is not provided and the upper surface of the copper foil pattern was zero.

< Experimental example >

Solder reflow evaluation was performed on the electrode substrates according to Example 1, Comparative Example 1, and Comparative Example 2, and the results are shown in FIGS. 9 to 11 below. More specifically, the solder reflow shape of the electrode substrate according to Example 1 is shown in FIG. 9, the solder reflow shape of the electrode substrate according to Comparative Example 1 is shown in FIG. 10, and the comparative example 2 The solder reflow shape of the electrode substrate according to FIG. 11 is shown below.

As shown in the results of FIGS. 9 to 11 below, in the case of Example 1, the step portion could prevent solder smearing, but in Comparative Examples 1 and 2, a short circuit defect due to the solder smear occurred.

As described above, according to an exemplary embodiment of the present application, since a metal foil pattern is formed using an inexpensive metal foil, there is a feature that the raw material cost can be reduced when manufacturing the transparent electrode substrate. In particular, according to an exemplary embodiment of the present application, after forming a metal foil pattern and a dry film resist pattern on an adhesive layer, performing a thermal bonding process at a temperature of 70° C. to 100° C., and then removing the dry film resist pattern, An embedded transparent electrode substrate in which the metal foil pattern is embedded into the adhesive layer may be manufactured.

In addition, according to an exemplary embodiment of the present application, it is possible to prevent an increase in haze of the transparent electrode substrate according to the roughness of the surface of the metal foil by heat-treating it at a temperature of 70°C to 100°C after forming the metal foil pattern on the adhesive layer. .

In addition, according to an exemplary embodiment of the present application, the step difference between the upper surface of the region where the groove pattern of the adhesive layer is not provided and the upper surface of the metal foil pattern is 1, the upper surface of the region where the groove pattern of the adhesive layer is not provided. μm to 50 μm higher configuration. Accordingly, it is possible to prevent the solder from spreading to the adjacent metal electrode during a solder reflow process for mounting the LED on the electrode substrate, and short-circuit defects can be prevented.

10: transparent substrate
20: adhesive layer
30: metal foil pattern
40: the upper surface of the region where the groove pattern of the adhesive layer is not provided
50: upper surface of the metal foil pattern
60: metal foil
70: dry film resist
80: dry film resist pattern
90: step

Claims (14)

transparent substrate;
an adhesive layer provided on the transparent substrate and including a groove pattern; and
It includes a metal foil pattern provided inside the groove pattern of the adhesive layer,
The step difference between the upper surface of the region where the groove pattern of the adhesive layer is not provided and the upper surface of the metal foil pattern is 1 μm to 50 μm higher than the top surface of the region where the groove pattern of the adhesive layer is not provided. is the substrate,
The buried type transparent electrode substrate of which the haze of the region not provided with the metal foil pattern of the buried type transparent electrode substrate is 5% or less. The buried transparent electrode substrate of claim 1, wherein the adhesive layer has a refractive index of 1.45 to 1.55. The method according to claim 1, wherein the ten-point average roughness (Rz) of the lower surface of the metal foil pattern facing the transparent substrate is greater than 0.5㎛,
The 10-point average roughness (Rz) of the upper surface of the region where the groove pattern of the adhesive layer is not provided is 0.1 μm or less. delete The embedded transparent electrode substrate of claim 1, wherein the adhesive layer includes a silane-modified epoxy resin, a bisphenol A-type phenoxy resin, an initiator, and a silane coupling agent. The buried type transparent electrode substrate of claim 1, wherein the metal foil pattern has a thickness of 2 µm to 20 µm. The buried transparent electrode substrate of claim 1, wherein the metal foil pattern includes a copper foil pattern or an aluminum foil pattern. The method according to claim 1, wherein the metal foil pattern comprises two types of metal foil patterns having different line widths,
The line width of one type of metal foil pattern is 3 μm to 30 μm,
The line width of the other metal foil pattern is 50 µm or more. forming a structure including a transparent substrate, an adhesive layer provided on the transparent substrate, and a metal foil provided on the adhesive layer;
laminating a dry film resist (DFR) on the metal foil;
patterning the metal foil and the dry film resist to form a metal foil pattern and a dry film resist pattern;
performing a thermal bonding process at a temperature of 70° C. to 100° C. to embed the metal foil pattern and the dry film resist pattern into the adhesive layer; and
removing the dry film resist pattern and completely curing the adhesive layer
A method of manufacturing a buried transparent electrode substrate comprising a. The method according to claim 9, wherein the step of forming the structure,
forming an adhesive layer on the metal foil, and forming a transparent substrate on the adhesive layer; or
Forming an adhesive layer on a transparent substrate, and forming a metal foil on the adhesive layer, the method of manufacturing an embedded transparent electrode substrate comprising the steps of. The method of claim 9 , wherein the adhesive layer has fluidity at a temperature of 70° C. or higher. The method according to claim 9, wherein the ten-point average roughness (Rz) of the surface of the adhesive layer before the thermal bonding process is greater than 0.5㎛,
The ten-point average roughness (Rz) of the surface of the adhesive layer after the thermal bonding process is 0.1 μm or less. The method according to claim 9, wherein the adhesive layer comprises a thermosetting adhesive composition or a UV curing adhesive composition,
The step of completely curing the adhesive layer, the method of manufacturing a buried transparent electrode substrate comprising the step of thermosetting or UV curing the adhesive layer at a temperature of 120 ℃ or more. The method of claim 9 , wherein the metal foil pattern is formed using a photolithography process.

Images