KR102202977B1 - Method for Fabricating Touch Sensor - Google Patents

Abstract

The present invention relates to a method of manufacturing a touch sensor capable of suppressing non-uniformity of the surface of a flexible substrate for manufacturing a touch sensor and suppressing defects during bonding and peeling with a carrier substrate using a temperature sensitive adhesive, including a conductor The step of preparing a film substrate; Bonding the protective film on the film substrate, and bonding the film substrate to which the protective film is bonded to the carrier substrate; To increase the adhesion between the film substrate and the carrier substrate, and between the protective film and the film substrate It includes; peeling the protective film in the state of lowering the adhesive force.

Description

Manufacturing method of touch sensor {Method for Fabricating Touch Sensor}

The present invention relates to a touch sensor, and specifically, a method of manufacturing a touch sensor capable of suppressing non-uniformity on the surface of a flexible substrate for manufacturing a touch sensor and suppressing defects in bonding and peeling with a carrier substrate using a temperature sensitive adhesive It is about.

As the touch input method is in the spotlight as the next-generation input method, attempts are being made to introduce the touch input method to a wider variety of electronic devices. Therefore, research and development on touch sensors that can be applied to various environments and that can accurately recognize touch are being actively conducted. have.

For example, in the case of an electronic device having a touch-type display, an ultra-thin flexible display that achieves ultra-light weight, low power and improved portability has been attracting attention as a next-generation display, and development of a touch sensor applicable to such a display has been required.

The flexible display refers to a display manufactured on a flexible substrate that can be bent, bent or rolled without loss of characteristics, and technology development is in progress in the form of flexible LCD, flexible OLED, and electronic paper.

In order to apply a touch input method to such a flexible display, a touch sensor having excellent bending and resilience and excellent flexibility and elasticity is required.

In order to manufacture a flexible substrate used for such a touch sensor, a technique related to a flexible substrate having excellent dimensional stability and low moisture transmittance has been disclosed by incorporating nanodiamond powder into a polyethylene naphthalate resin as one of the prior art. Patent No. 10-1078059)

As another method for manufacturing a flexible substrate, a technology for a polyarylate resin having a new structure improved by introducing a silicon-containing side chain into a polyarylate resin has been disclosed. (Republic of Korea Patent Publication No. 10-1992-0012125 arc)

However, the manufacturing process of such a conventional flexible substrate uses a high heat-resistant resin to suppress shape change at high temperatures in the substrate manufacturing process. This has a problem that makes it difficult to control the phase difference, so it is not applicable to the manufacturing of an actual touch sensor. There is a limit.

In order to solve the difficulty in controlling the phase difference, when a material film other than a high heat-resistant resin is used, the film surface is uneven after bonding to the carrier substrate due to wrinkles generated after heat treatment.

Such non-uniformity of the film surface causes a decrease in the precision of a subsequent process, resulting in problems such as a decrease in device characteristics and a decrease in yield.

Korean Patent Registration No. 10-1078059 Republic of Korea Patent Publication No. 10-1992-0012125

The present invention is to solve the problem of the manufacturing process of the touch sensor of the prior art, and provides a method of manufacturing a touch sensor using a temperature-sensitive adhesive to suppress defects in bonding and peeling with a carrier substrate. There is a purpose.

In the present invention, the protective film is bonded to the heat-treated conductive film using a first adhesive, and bonded to the glass using a temperature-sensitive second adhesive to separate the first and second adhesives according to the temperature of the first and second adhesives. It is an object of the present invention to provide a method of manufacturing a touch sensor capable of solving the peeling failure between a thermoplastic resin and a temperature-sensitive second adhesive.

An object of the present invention is to provide a method of manufacturing a touch sensor in which a protective film is bonded on a metal oxide layer and a glass bonding and patterning process is performed to suppress surface unevenness.

The present invention provides a method for manufacturing a touch sensor in which a material having no difficulty in controlling a phase difference is used for manufacturing a flexible substrate, and a protective film made of a protective substrate and an adhesive is bonded to the wrinkles generated after heat treatment to improve the surface unevenness phenomenon. There is a purpose.

An object of the present invention is to provide a method of manufacturing a touch sensor capable of maintaining the precision of a subsequent process by suppressing the unevenness of the film surface without using a high heat-resistant resin.

Objects of the present invention are not limited to the above-mentioned objects, and other objects not mentioned will be clearly understood by those skilled in the art from the following description.

The method of manufacturing a touch sensor according to the present invention for achieving such an object includes the steps of preparing a film substrate including a conductor; bonding a protective film on the film substrate, and attaching the film substrate to which the protective film is bonded to a carrier substrate. Bonding; It characterized in that it comprises a; increasing the adhesion between the film substrate and the carrier substrate, peeling the protective film in a state in which the adhesion between the protective film and the film substrate is lowered.

Here, by bonding the protective film on the film substrate, the surface wrinkles of the film substrate are removed, and the film substrate is bonded to the carrier substrate.

In addition, in the step of bonding the protective film on the film substrate, bonding is performed using a first pressure-sensitive adhesive, and in the step of bonding the film substrate to the carrier substrate, bonding is performed using a second pressure-sensitive adhesive different from the first pressure-sensitive adhesive.

And the first pressure-sensitive adhesive is selected from the group of polyester-based, polyether-based, urethane-based, epoxy-based, silicone-based, and acrylic-based materials, and is characterized in that it is a heat-curable or UV-curable curable adhesive.

And the second pressure-sensitive adhesive is characterized by using a temperature-sensitive pressure-sensitive adhesive that contains a side-chain crystalline polymer and exhibits adhesive strength at a temperature equal to or higher than the melting point of the side-chain crystalline polymer.

The side chain crystalline polymer is characterized in that it is made of a crosslinked polymer obtained by adding a metal chelate compound to the side chain crystalline polymer and performing a crosslinking reaction.

In addition, the side chain crystalline polymer is characterized in that it crystallizes at a temperature below the melting point and exhibits fluidity at a temperature above the melting point.

And the side chain crystalline polymer is characterized in that it consists of a copolymer obtained by polymerizing a (meth)acrylate having a linear alkyl group having 16 or more carbon atoms, a (meth)acrylate having an alkyl group having 1 to 6 carbon atoms, and a polar monomer. do.

And the metal chelate compound is characterized in that the aluminum trisacetylacetonate.

And in the step of bonding the protective film on the film substrate, a pressure-sensitive adhesive having Tg <0 is used, and in the step of bonding the film substrate to the carrier substrate, a temperature-sensitive adhesive is used, and optionally the film substrate and the carrier substrate are increased by increasing the temperature. It is characterized in that to increase the adhesion of.

In addition, when the temperature is increased to increase the adhesive strength between the film substrate and the carrier substrate, the adhesive strength of the pressure-sensitive adhesive used in the step of bonding the protective film on the film substrate is lowered.

And after the protective film is peeled off, the manufacturing step of the laminated structure including patterning of the conductor is performed, and the base film and the carrier substrate are separated.

And the conductor is a metal oxide conductor, indium tin oxide (ITO), indium zinc oxide (IZO), indium zinc oxide (IZTO), aluminum zinc oxide (AZO), gallium zinc oxide (GZO), florin tin oxide ( FTO), indium tin oxide-silver-indium tin oxide (ITO-Ag-ITO), indium zinc oxide-silver-indium zinc oxide (IZO-Ag-IZO), indium zinc oxide-silver-indium zinc oxide (IZTO) -Ag-IZTO) and aluminum zinc oxide-silver-aluminum zinc oxide (AZO-Ag-AZO).

And the material constituting the film substrate is characterized in that the thermoplastic resin.

And the material constituting the film substrate is characterized in that the cyclic olefin polymer (Cyclo-olefin polymer; COP).

The manufacturing method of the touch sensor according to the present invention has the following effects.

First, it is possible to suppress defects in bonding and peeling with a carrier substrate by using a temperature-sensitive adhesive.

Second, by bonding a protective film on the metal oxide layer and performing a glass bonding and patterning process, surface unevenness can be suppressed.

Third, it is possible to maintain the precision of subsequent processes by suppressing the unevenness of the film surface without using a high heat-resistant resin.

Fourth, since the surface unevenness is improved and the protective film is removed again afterwards, it can be easily applied to the existing process.

1 is a flow chart showing a manufacturing process of a touch sensor according to the present invention
2A to 2D are cross-sectional views showing a manufacturing process of a touch sensor according to the present invention.
3 is a graph showing the adhesive strength according to the temperature of the temperature-sensitive adhesive according to the present invention

Hereinafter, a detailed description will be given of a preferred embodiment of a method of manufacturing a touch sensor according to the present invention.

Features and advantages of the method of manufacturing a touch sensor according to the present invention will become apparent through detailed description of each embodiment below.

1 is a flow chart showing a manufacturing process of a touch sensor according to the present invention.

And Figures 2a to 2d is a cross-sectional view showing a manufacturing process of the touch sensor according to the present invention.

The present invention uses a material without difficulty in controlling the phase difference for manufacturing a flexible substrate, and improves the surface unevenness phenomenon by bonding a protective film made of a protective substrate and an adhesive to wrinkles generated after heat treatment to improve the precision of subsequent processes. I made it possible to keep it.

In particular, the heat-treated conductive film is bonded to the protective film using a first adhesive, and a temperature-sensitive second adhesive is used to bond the protective film to the glass so that the difference in adhesive strength according to the temperature of the first and second adhesives is reduced when the protective film is separated afterwards. By using it, it is possible to solve the defective peeling between the thermoplastic resin and the temperature-sensitive second adhesive.

For this purpose, the manufacturing process of the touch sensor according to the present invention includes the steps of manufacturing a thermoplastic resin including a metal oxide conductor, improving conductivity by heat treatment, bonding a protective film to the heat treated conductive film, and using a temperature sensitive adhesive. Bonding to a glass serving as a carrier substrate through a medium, peeling off the protective film, fabricating a laminated structure including patterning of a conductor, and peeling the laminated structure produced on the thermoplastic resin from the glass Thus, to manufacture a laminated structure including the electrode layer patterned on the flexible substrate.

Here, the step of bonding the protective film to the heat-treated conductive film includes bonding a protective film made of a protective substrate and an adhesive on the metal oxide layer of the laminate consisting of a metal oxide and a thermoplastic resin obtained by performing a conductive improvement step by heat treatment. will be.

By bonding the protective film to the glass serving as the carrier substrate in this way, uneven wrinkles on the film surface generated in the heat treatment process for improving conductivity are removed, and the film surface is bonded in a uniform state.

In the step of peeling the laminated structure made on the thermoplastic resin from the glass, the adhesive strength between the pressure-sensitive adhesive for the protective film and the metal oxide layer decreases by heating, and the adhesive strength between the thermosensitive adhesive and the thermoplastic resin increases to solve the peeling failure. I made it possible.

The manufacturing process of the touch sensor according to the present invention will be described in detail as follows.

First, a film substrate 21 including a metal oxide conductor 22 is manufactured (S101), and a heat treatment process for improving conductivity is performed (S102).

Here, the metal oxide is indium tin oxide (ITO), indium zinc oxide (IZO), indium zinc tin oxide (IZTO), aluminum zinc oxide (AZO), gallium zinc oxide (GZO), florin tin oxide (FTO), indium tin Oxide-silver-indium tin oxide (ITO-Ag-ITO), indium zinc oxide-silver-indium zinc oxide (IZO-Ag-IZO), indium zinc oxide-silver-indium zinc tin oxide (IZTO-Ag-IZTO) And metal oxides consisting of aluminum zinc oxide-silver-aluminum zinc oxide (AZO-Ag-AZO), and are not limited to these materials.

In addition, the material constituting the film substrate 21 is a thermoplastic resin, and it is preferable to use a COP (Cyclo-olefin polymer).

Cyclo-olefin polymer (COP) is, for example, a polymer obtained from a cyclic monomer such as norbornene, and has excellent transparency, heat resistance, and chemical resistance compared to existing olefin-based polymers, and has a birefringence and water absorption rate. This is very low and is suitable for manufacturing flexible substrates.

Here, the material constituting the film substrate 21 is not limited to a cyclic olefin polymer (COP), but a thermoplastic elastomer, a styrenic material, or an olefin-based material. (olefenic materials), polyolefin, polyurethane thermoplastic elastomers, polyamides, synthetic rubbers, polydimethylsiloxane (PDMS), polybutadiene, poly Isobutylene, poly(styrene-butadiene-styrene) [poly(styrene-butadiene-styrene)], polyurethanes, polychloroprene, polymethacrylate, polyacryl , Polycarbonate, polyaryte, polysulfone, polyimide, polyethylene terephthalate, polyethylene naphthalate, silicone, and combinations thereof It is natural that it may be selected from the group.

The film substrate may have a function of a retardation film for the purpose of reducing the pattern visibility of the touch sensor or improving the optical performance of the display.

The cross-sectional configuration in a state in which the heat treatment process for improving conductivity is performed is the same as in FIG. 2A.

It can be seen that the film substrate 21 has a curl by a heat treatment process for improving conductivity.

A protective film 23 made of a protective substrate and an adhesive is bonded on the film substrate 21 as shown in FIG. 2B. (S103) Surface wrinkles of the film substrate are removed by bonding the protective film on the film substrate. It can be seen that it is bonded to the carrier substrate in a uniform state.

Here, the protective substrate is preferably polyethylene terephthalate (PET), but is not limited thereto.

Specifically, polyester resins such as polyethylene terephthalate (PET), polyethylene isophthalate, polyethylene naphthalate, and polybutylene terephthalate; Cellulose resins such as diacetyl cellulose and triacetyl cellulose; Polycarbonate resin; Acrylic resins such as polymethyl (meth)acrylate and polyethyl (meth)acrylate; Styrene resins such as polystyrene and acrylonitrile-styrene copolymer; Polyolefin resins such as polyethylene, polypropylene, polyolefin having a cyclo-based or norbornene structure, and ethylene-propylene copolymer; Vinyl chloride resin; Amide resins such as nylon and aromatic polyamide; Imide resin; Polyethersulfone resin; Polyether ether ketone resin; Sulfide polyphenylene resin; Vinyl alcohol resin; Vinylidene chloride resin; Vinyl butyral resin; Allylate resin; Polyoxymethylene resin; It may be selected from the group consisting of a film composed of a thermoplastic resin such as an epoxy resin, and a combination thereof.

In addition, a film made of a thermosetting resin such as (meth)acrylic, urethane, acrylic urethane, epoxy, silicone, or an ultraviolet curable resin may be used.

And the pressure-sensitive adhesive constituting the protective film 23 is a polyester-based, polyether-based, urethane-based, epoxy-based, silicone-based, acrylic-based pressure-sensitive adhesive, and such a pressure-sensitive adhesive is a heat-curable or UV-curable adhesive.

Then, as shown in Fig. 2c, the step of bonding to the glass serving as the carrier substrate 25 is performed through an adhesive (S104).

The adhesive used here is a temperature sensitive adhesive.

The temperature-sensitive adhesive refers to an adhesive whose adhesive strength changes in response to temperature changes.

The temperature-sensitive adhesive used in an embodiment of the present invention is a temperature-sensitive adhesive that contains a side-chain crystalline polymer and exhibits adhesive strength at a temperature equal to or higher than the melting point of the side-chain crystalline polymer.

The side chain crystalline polymer is preferably made of a crosslinked polymer obtained by adding a metal chelate compound to the side chain crystalline polymer and performing a crosslinking reaction.

The side-chain crystalline polymer crystallizes at a temperature below the melting point, and also exhibits fluidity at a temperature above the melting point.

The side chain crystalline polymer is preferably composed of a copolymer obtained by polymerizing a (meth)acrylate having a linear alkyl group having 16 or more carbon atoms, a (meth)acrylate having an alkyl group having 1 to 6 carbon atoms, and a polar monomer.

In addition, the metal chelate compound is preferably at least one selected from an acetylacetone coordination compound of a polyvalent metal and an acetoacetic acid ester coordination compound of a polyvalent metal, and the metal chelate compound is preferably aluminum trisacetylacetonate.

Next, as shown in FIG. 2D, the protective film 23 on the film substrate 21 bonded to the glass serving as the carrier substrate 25 is peeled (S105), and the manufacturing step of the laminated structure including the patterning of the conductor is performed. .(S106)

When the laminated structure is fabricated on the film substrate 21 in this way, the glass serving as the carrier substrate 25 and the laminated structure are peeled off. (S107)

The process of peeling the protective film 23 on the film substrate 21 bonded to the glass proceeds using the change in adhesive force according to the following temperature.

3 is a graph showing the adhesive strength according to the temperature of the temperature-sensitive adhesive according to the present invention.

In an embodiment of the present invention, the protective film 23 is made of a protective substrate and a pressure-sensitive adhesive, the pressure-sensitive adhesive is a pressure-sensitive adhesive having Tg <0 or less, and the pressure-sensitive adhesive used in the step of bonding to the glass serving as the carrier substrate 25 is a temperature-sensitive adhesive. It is an adhesive whose adhesive strength increases as the temperature rises.

Therefore, when the process of peeling the protective film 23 on the film substrate 21 bonded to the glass is performed at a temperature of 40° C. or higher, the adhesive strength between the protective film adhesive and the metal oxide layer decreases as shown in the graph of FIG. 3. In addition, since the adhesive force between the temperature-sensitive adhesive and the thermoplastic resin is increased, defects in peeling can be suppressed.

The manufacturing method of the touch sensor according to the present invention uses a material without difficulty in controlling the phase difference for manufacturing a flexible substrate, and improves surface unevenness by bonding a protective film made of a protective substrate and an adhesive to wrinkles generated after heat treatment. Therefore, it is possible to maintain the precision of the subsequent process.

In addition, the heat-treated conductive film is bonded to the protective film using a first adhesive, and a temperature-sensitive second adhesive is used to bond the protective film to the glass, so that the difference in adhesive strength according to the temperature of the first and second adhesives is determined during subsequent separation of the protective film. By using it, it is possible to solve the defective peeling between the thermoplastic resin and the temperature-sensitive second adhesive.

As described above, it will be understood that the present invention is implemented in a modified form without departing from the essential characteristics of the present invention.

Therefore, the specified embodiments should be considered from a descriptive point of view rather than a limiting point of view, and the scope of the present invention is shown in the claims rather than the above description, and all differences within the scope equivalent thereto are included in the present invention. It will have to be interpreted.

21. Film base 22. Conductor
23. Protective film 24. Adhesive
25. Carrier substrate

Claims (15)

Manufacturing a film substrate including a conductor;
Heat-treating the film substrate;
Bonding a protective film on the heat-treated film substrate, and bonding the film substrate to which the protective film is bonded to a carrier substrate; And
The method of manufacturing a touch sensor, comprising: peeling the protective film while increasing the adhesion between the film substrate and the carrier substrate and lowering the adhesion between the protective film and the film substrate. The method for manufacturing a touch sensor according to claim 1, wherein the surface wrinkles of the film substrate are removed by bonding the protective film on the film substrate to be bonded to the carrier substrate. The method of claim 1, wherein in the step of bonding the protective film on the film substrate, bonding is performed using a first pressure-sensitive adhesive, and in the step of bonding the film substrate to the carrier substrate, bonding is performed using a second pressure-sensitive adhesive different from the first pressure-sensitive adhesive. A method of manufacturing a touch sensor, characterized in that. The method of claim 3, wherein the first pressure-sensitive adhesive is selected from the group of polyester-based, polyether-based, urethane-based, epoxy-based, silicone-based, and acrylic-based materials, and is a heat-curable or UV-curable curable adhesive. Manufacturing method. The method of manufacturing a touch sensor according to claim 3, wherein the second pressure-sensitive adhesive contains a side-chain crystalline polymer and uses a temperature-sensitive pressure-sensitive adhesive that exhibits adhesion at a temperature equal to or higher than the melting point of the side-chain crystalline polymer. The method for manufacturing a touch sensor according to claim 5, wherein the side chain crystalline polymer is made of a crosslinked polymer obtained by adding a metal chelate compound to the side chain crystalline polymer and performing a crosslinking reaction. The method of manufacturing a touch sensor according to claim 5, wherein the side chain crystalline polymer is crystallized at a temperature below the melting point and exhibits fluidity at a temperature above the melting point. The method according to claim 6 or 7, wherein the side-chain crystalline polymer is a polymerization of a (meth)acrylate having a linear alkyl group having 16 or more carbon atoms, a (meth)acrylate having an alkyl group having 1 to 6 carbon atoms, and a polar monomer. A method for manufacturing a touch sensor, comprising a copolymer obtained by making it. The method of claim 6, wherein the metal chelate compound is aluminum trisacetylacetonate. The method of claim 1, wherein in the step of bonding the protective film on the film substrate, an adhesive having Tg <0 is used, and in the step of bonding the film substrate to the carrier substrate, a temperature-sensitive adhesive is used,
A method of manufacturing a touch sensor, characterized in that it is possible to selectively increase the adhesion between the film substrate and the carrier substrate by increasing the temperature. The method of claim 10, wherein if the temperature is increased to increase the adhesion between the film substrate and the carrier substrate,
Method of manufacturing a touch sensor, characterized in that the adhesive strength of the pressure-sensitive adhesive used in the step of bonding the protective film on the film substrate is lowered. The method of manufacturing a touch sensor according to claim 1, wherein after the protective film is peeled off, the manufacturing step of the laminated structure including patterning of the conductor is performed, and the base film and the carrier substrate are separated. The method of claim 1, wherein the conductor is a metal oxide conductor,
Indium tin oxide (ITO), indium zinc oxide (IZO), indium zinc oxide (IZTO), aluminum zinc oxide (AZO), gallium zinc oxide (GZO), florin tin oxide (FTO), indium tin oxide-silver-indium Tin oxide (ITO-Ag-ITO), indium zinc oxide-silver-indium zinc oxide (IZO-Ag-IZO), indium zinc oxide-silver-indium zinc oxide (IZTO-Ag-IZTO) and aluminum zinc oxide- A method of manufacturing a touch sensor, characterized in that it is selected from metal oxides consisting of silver-aluminum zinc oxide (AZO-Ag-AZO). The method of claim 1, wherein the material constituting the film substrate is a thermoplastic resin. The method of claim 14, wherein the material constituting the film substrate is a cyclic olefin polymer (COP).

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