KR20200037977A - Touch sensor and method of fabricating the same - Google Patents

Abstract

According to embodiments of the present invention, a touch sensor comprises: a separation layer; a first protective layer formed on the separation layer; and an electrode layer disposed on the first protective layer and including sensing electrodes. The elastic modulus and thickness of the first protective layer can satisfy a predetermined relational expression. Through improved elastic properties of the first protective layer, damage to a pad in a high temperature bonding process can be prevented.

Description

Touch sensor and its manufacturing method {TOUCH SENSOR AND METHOD OF FABRICATING THE SAME}

The present invention relates to a touch sensor and a method for manufacturing the same. More specifically, the present invention relates to a touch sensor including a conductive pattern and an insulating layer and a method for manufacturing the same.

The touch screen panel is an input device that allows a user's command to be input by selecting an instruction displayed on a screen such as an image display device with a human hand or an object. The touch screen panel is disposed on the front face of the image display device to convert a contact position directly contacting a human hand or object into an electrical signal. Accordingly, the instruction content selected at the contact position can be transmitted as an input signal.

The touch screen panel may include a touch sensor substrate and touch sensing electrodes arranged on the touch sensor substrate. In addition, a circuit member such as a flexible printed circuit board (FPCB) may be combined with the touch screen panel to connect the touch sensing electrodes to a driving integrated circuit (IC) chip.

In order to connect the FPCB with the touch sensing electrodes, a heat-pressing process of the FPCB may be performed on a bonding pad disposed on the touch sensor substrate. In this case, the touch sensor substrate may be deformed by the heat-pressing process performed at a high temperature, in which case cracking of the bonding pad may occur and bonding failure may occur.

In addition, in recent years, in order to be applied to an image display device such as a thin-type smart phone having flexible characteristics, the thickness of the touch screen panel also needs to be reduced, and accordingly, it is not easier to implement desirable characteristics of the touch sensor substrate.

For example, as in Korean Patent Publication No. 2014-0092366, a touch screen panel in which a touch sensor is combined with various image display devices has been developed, but it has not provided a method for securing sufficient circuit connection reliability and mechanical stability as described above. .

Korean Patent Publication No. 2014-0092366

One object of the present invention is to provide a touch sensor having improved mechanical and electrical reliability.

One object of the present invention is to provide a method of manufacturing a touch sensor having improved mechanical and electrical reliability.

One object of the present invention is to provide a window stack or an image display device including the touch sensor.

1. separation layer; A first protective layer formed on the separation layer; And an electrode layer disposed on the first protective layer and including sensing electrodes, wherein the first protective layer satisfies Expression 1 below:

[Equation 1]

5.2 × 10 ³ MPa * ㎛ ² ≤TD ² ≤5.2 × 10 ⁴ MPa * ㎛ ²

 (In Formula 1, T represents the modulus of elasticity (MPa) at 25 ° C of the first protective layer, and D represents the thickness (µm) of the first protective layer).

2. In the above 1, the rate of change of the elastic modulus defined by the following Equation 2 of the first protective layer is 15% or less, the touch sensor:

[Equation 2]

Modulus of elasticity change (%) = {(25 ° C modulus-140 ° C modulus) / (25 ° C modulus)} × 100.

3. In the above 1, the elastic modulus at 25 ℃ of the first protective layer is 1000 to 2500 MPa, the touch sensor.

4. In the above 1, the thickness of the first protective layer is 0.5 to 10㎛, touch sensor.

5. In the above 1, the tensile strength of the first protective layer is 30 to 60 N / mm ² , the touch sensor.

6. In the above 1, wherein the first protective layer satisfies the following equation 3, a touch sensor:

[Equation 3]

5 N / mm ² * ㎛≤I / D ≤25 N / mm ² * ㎛

(In formula 3, I represents the tensile strength (N / mm ² ) of the first protective layer, and D represents the thickness (µm) of the protective layer).

7. In the above 1, the glass transition temperature of the first protective layer is 150 to 210 ℃, touch sensor.

8. In the above 1, further comprising a second protective layer formed on the electrode layer, the second protective layer satisfies the expression (1), the touch sensor.

9. The touch sensor according to the above 1, wherein the first protective layer is formed from a curable resin composition.

10. forming a separation layer on the carrier substrate; Forming a first protective layer satisfying the following Equation 1 on the separation layer; Forming an electrode layer including sensing electrodes on the first protective layer; And peeling the carrier substrate from the separation layer.

[Equation 1]

5.2 × 10 ³ MPa * ㎛ ² ≤TD ² ≤5.2 × 10 ⁴ MPa * ㎛ ²

 (In Formula 1, T represents the modulus of elasticity (MPa) at 25 ° C of the first protective layer, and D represents the thickness (µm) of the first protective layer).

11. The method of 10 above, wherein the forming of the electrode layer includes forming traces electrically connected to the sensing electrodes and pads connected to ends of the traces.

12. The method of 11 above, further comprising the step of heat-pressing the pads and the flexible circuit board (FPCB).

13. The method of manufacturing a touch sensor according to the above 12, wherein the rate of change of elastic modulus defined by the following Equation 2 of the first protective layer is 15% or less.

[Equation 2]

Modulus of elasticity change (%) = {(25 ° C modulus-140 ° C modulus) / (25 ° C modulus)} × 100.

14. Window substrate; And a touch sensor according to any one of 1 to 9 above.

15. The window laminate according to the above 14, further comprising an optical layer disposed between the window substrate and the touch sensor.

16. display panel; And a touch sensor stacked on the display panel and according to any one of 1 to 9 above.

17. The image display device according to claim 16, further comprising a point adhesive layer bonding the display panel and the touch sensor to each other.

According to embodiments of the present invention, a protective layer covering electrodes of a touch sensor is formed, and the protective layer has an improved modulus of elasticity at a high temperature and has an improved tensile strength, thereby providing a heat-pressing process for a flexible printed circuit board (FPCB). The electrodes or pads can be sufficiently protected. Therefore, it is possible to suppress cracks, peelings, and defects in bonding of the pads by the above-mentioned heat pressing process.

In some embodiments, a separation layer may be formed under the protection layer, and the separation layer may be substantially provided as a substrate together with the protection layer. Therefore, a separate substrate or substrate may be omitted to implement a thin touch sensor.

1 is a schematic cross-sectional view showing a touch sensor according to example embodiments.
2 is a schematic plan view for explaining the structure of an electrode layer according to example embodiments.
3 to 6 are schematic cross-sectional views illustrating a method of manufacturing a touch sensor according to example embodiments,
7 is a schematic cross-sectional view illustrating a window stack and an image display device according to example embodiments.

Embodiments of the present invention includes a separation layer, a protective layer, and an electrode layer, and provides a touch sensor and a method of manufacturing the electrode layer with reliability improved by mechanical properties of the protective layer. In addition, a window stack or image display device including the touch sensor is provided.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. However, the following drawings attached to the present specification are intended to illustrate preferred embodiments of the present invention, and serve to further understand the technical idea of the present invention together with the contents of the present invention, so the present invention is described in such drawings. It should not be interpreted as being limited to the matter.

1 is a schematic cross-sectional view showing a touch sensor according to example embodiments.

Referring to FIG. 1, the touch sensor may include a first protective layer 110, an electrode layer 120, and a second protective layer 130 sequentially stacked from the top surface of the separation layer 100.

The separation layer 100 may include a polymer organic film, and includes, as non-limiting examples, polyimide-based polymers, polyvinyl alcohol-based polymers, polyamic acid-based polymers, polyamides ( polyamide) polymer, polyethylene polymer, polystylene polymer, polynorbornene polymer, phenylmaleimide copolymer polymer, polyazobenzene polymer, polyphenyl Polyphenylenephthalamide-based polymer, polyester-based polymer, polymethyl methacrylate-based polymer, polyarylate-based polymer, cinnamate-based polymer, coumarin Polymer materials such as polymers based on polymers, phthalimidine polymers, chalcone polymers, aromatic acetylene polymers, etc. The. These may be used alone or in combination of two or more.

In some embodiments, the separation layer 100 is formed on a carrier substrate 50 (see FIG. 3), such as a glass substrate, and is formed to facilitate a peeling process from the carrier substrate after the touch sensor is formed. Can be.

The first protective layer 110 may be formed on the top surface of the separation layer 100. The first protective layer 110 is provided as a support layer for forming the electrode layer 120, and may function as a protective layer for electrode patterns included in the electrode layer 120.

The first protective layer 110 may include an organic insulating material or an inorganic insulating material. When the first protective layer 110 includes an inorganic insulating material, for example, silicon oxide, silicon nitride, silicon oxynitride, and the like may be included.

When the first protective layer 110 includes an organic insulating material, for example, it may be formed using a curable resin composition. The curable resin composition may include a curable resin and a solvent.

The curable resin is, for example, epoxy resin cyclic olefin polymer (COP), styrene resin, vinyl chloride resin, acrylic resin, polyphenylene ether resin, polyarylene sulfide resin, polycarbonate resin, polyester Resins, polyamide resins, polyethersulfone resins, polysulfone resins, polyimide resins, rubbers, elastomers, and the like.

The solvent is alcohol-based (methanol, ethanol, isopropanol, butanol, propylene glycol methoxy alcohol, etc.), ketone-based (methyl ethyl ketone, methyl butyl ketone, methyl isobutyl ketone, diethyl ketone, dipropyl ketone, etc.), acetate-based (Methyl acetate, ethyl acetate, butyl acetate, propylene glycol methoxy acetate, etc.), cellosolve type (methyl cellosolve, ethyl cellosolve, propyl cellosolve, etc.), hydrocarbon type (normal hexane, normal heptane, benzene, toluene, xyl Solvents such as Ren), and these may be used alone or in combination of two or more.

The curable resin composition may further include a curing agent. The curing agent may include, for example, a compound capable of crosslinking with the curable resin, such as an amino group, a carboxyl group, a hydroxyl group, an epoxy group, and an isocyanate group.

The curable resin composition may further include additives such as inorganic particles (eg, silicate, zirconia, alumina, titania, etc.), sensitizers, surfactants, antifoaming agents, and the like.

The electrode layer 120 may include electrode patterns such as sensing electrodes, traces, and pads for touch sensing. The structure and / or structure of the electrode layer 120 will be described in more detail with reference to FIG. 2.

The second protective layer 130 may cover or passivate the electrode patterns included in the electrode layer 120 together with the first protective layer 110. The second protective layer 130 may include an organic insulating material or an inorganic insulating material. In some embodiments, the second protective layer 130 may include an insulating material that is substantially the same as or similar to the first protective layer 110.

According to exemplary embodiments, the first protective layer 110 may satisfy a relationship between elastic modulus (eg, tensile modulus) (T: MPa) and thickness (D: μm) represented by Equation 1 below. .

[Equation 1]

5.2 × 10 ³ MPa * ㎛ ² ≤TD ² ≤5.2 × 10 ⁴ MPa * ㎛ ²

Within the range of Equation 1, the change in elastic modulus at high temperature of the first protective layer 110 is suppressed so that the first protective layer 110 is substantially a substrate for the electrode patterns of the electrode layer 130 in a high temperature or heating process. Provided, it is possible to maintain desirable elastic properties.

When the TD ² value of the first protective layer 110 is less than about 5.2 × 10 ³ MPa * ㎛ ² , it is easily damaged or deformed in a high-temperature process, for example, the pad and the first during the bonding process of the flexible printed circuit board (FPCB) The protective layer 120 may be damaged or damaged.

When the TD ² value of the first protective layer 110 exceeds about 5.2 × 10 ⁴ MPa * µm ² , the elasticity provided through the first protective layer 110 is weakened, so that the impact spreads or absorbs when the FPCB is pressed. It may not be. Therefore, cracks or breakage of the pad may be caused by the pressing.

In some embodiments, the elastic modulus of the first protective layer 110 may be in the range of about 1000 to 2500 MPa at 25 ° C. The thickness of the first protective layer 110 may be about 0.5 to 10㎛. Within the range of the elastic modulus and thickness, it is possible to more effectively maintain proper support stiffness for the electrode pattern while absorbing the impact in the pressing process within the range.

According to exemplary embodiments, the rate of change of the modulus of elasticity at 140 ° C compared to the modulus of elasticity at 25 ° C of the first protective layer 110 is about 15% or less, and preferably about 10% or less. The elastic modulus change rate may be defined by Equation 2 below.

[Equation 2]

Modulus of elasticity change (%) = {(25 ℃ modulus-140 ℃ modulus) / (25 ℃ modulus)} × 100

Accordingly, the elastic properties of the first protective layer 110 are maintained even in a high temperature and heating process, so that the electrode pattern can be more stably supported and protected.

In some embodiments, the glass transition temperature (Tg) of the first protective layer 110 may be about 150 ° C or higher. In this case, the effect of suppressing the elastic modulus change at the high temperature described above can be secured more easily. Preferably, the glass transition temperature (Tg) of the first protective layer 110 may range from about 150 to 210 ° C.

In some embodiments, the tensile strength of the first protective layer 110 may range from about 30 to 60 N / mm ² . Within this range, resistance and support in the pressurization process can be secured.

In some embodiments, the first protective layer 110 may satisfy a relationship between tensile strength (I: N / mm ² ) and thickness (D: μm) represented by Equation 2 below.

[Equation 3]

5 N / mm ² * ㎛≤I / D ≤25 N / mm ² * ㎛

When the I / D shown in Equation 3 is satisfied, a change in elastic modulus is suppressed even in a high-temperature heating process, and process stability through the first protective layer 110 may be further improved.

According to exemplary embodiments, the second protective layer 130 may also satisfy elastic modulus, thickness, and tensile strength values and characteristics substantially the same as or similar to the first protective layer 110 described above. In this case, as the improved passivation effect is provided at the top and bottom of the electrode layer 120, the electrode patterns included in the electrode layer 120 may be protected from mechanical damage such as cracks and peeling.

As illustrated in FIG. 1, a first protective film 150 and a second protective film 155 may be formed on the bottom surface of the separation layer 100 and the top surface of the second protective layer 130, respectively. The first and second protective films 150 may include, for example, a release film. For example, the first and second protective films may include resin materials such as polyethylene (PE), polyethylene terephthalate (PET), polymethyl methacrylate (PMMA), and the like.

2 is a plan view illustrating a structure of an electrode layer according to example embodiments. For example, FIG. 2 shows the electrode layer structure of a mutual capacitance type touch sensor.

2, the touch sensor may include, for example, sensing electrodes 210 and 230, traces 217 and 237 and pads 250 disposed on the first protective layer 110. You can.

The sensing electrodes 210 and 230 may include first sensing electrodes 210 and second sensing electrodes 230.

The first sensing electrodes 210 may be arranged, for example, in a column direction or a Y-axis direction. In some embodiments, the first sensing electrodes 210 may be physically separated into island-type unit electrodes, respectively. In this case, the first sensing electrodes 210 neighboring in the column direction may be electrically connected to each other by the bridge electrode 215.

Accordingly, a first sensing electrode row extending in the column direction may be formed by the plurality of first sensing electrodes 210. Also, a plurality of the first sensing electrode columns may be arranged along a row direction (or X-axis direction).

The second sensing electrodes 230 may be arranged, for example, in a row direction (eg, X direction). Accordingly, a second sensing electrode row extending in the row direction may be formed by the second sensing electrodes 230. Also, a plurality of the rows of the second sensing electrodes may be arranged along the column direction.

In some embodiments, the second sensing electrodes 230 neighboring in the second direction may be physically or electrically connected to each other by a connection part 235. For example, the connection unit 235 is integrally formed at the same level as the second sensing electrodes 230 and may be provided as a substantially single member with the second sensing electrodes 230.

For example, an insulating layer (not shown) that at least partially covers the connection portion 235 is formed, and a bridge electrode 215 is formed on the insulating layer, so that adjacent first sensing electrodes 210 are second. The sensing electrodes 230 may be electrically connected to each other through the bridge electrode 215 while maintaining insulation.

In some embodiments, the first sensing electrodes 210 are integrally connected along the first direction by a connection unit, and the second sensing electrodes 230 may be electrically connected to each other through a bridge electrode.

The sensing electrodes 210 and 230 and / or the bridge electrode 215 are silver (Ag), gold (Au), copper (Cu), aluminum (Al), platinum (Pt), palladium (Pd), chromium (Cr) ), Titanium (Ti), tungsten (W), niobium (Nb), tantalum (Ta), vanadium (V), iron (Fe), manganese (Mn), cobalt (Co), nickel (Ni), zinc (Zn) ), Tin (Sn) or alloys thereof (eg, silver-palladium-copper (APC)). These may be used alone or in combination of two or more.

The sensing electrodes 210 and 230 and / or the bridge electrode 215 are, for example, indium tin oxide (ITO), indium zinc oxide (IZO), zinc oxide (ZnO), indium zinc tin oxide (IZTO), cadmium It may also include a transparent conductive oxide such as tin oxide (CTO).

For example, the first The active region A is defined in the central region of the protective layer 110, and the sensing electrodes 210 and 230 can be defined on the active region A. The active area A may be a substantial sensing area in which a user's touch is sensed.

The peripheral area of the active area A may be provided as a trace area. The trace area may overlap with a bezel portion of the image display device, for example. The traces 217 and 237 may include first traces 217 and second traces 237.

For example, the first traces 217 may branch and extend from each of the first sensing electrode rows. The second traces 237 may branch from each of the second sensing electrode rows and extend.

The traces 217 and 237 extend toward one end of the first protective layer 110 and may be collected in the bonding region B. Each of the traces 217 and 237 in the bonding area B may be connected to the pads 250. In some embodiments, the pad 250 may be a terminal portion integrally connected with the distal ends of each trace 217 and 237.

The bonding region B may be provided as a bonding region for electrically connecting the sensing electrodes 210 and 230 and the driving integrated circuit IC through the pads 250. According to exemplary embodiments, a circuit connection structure such as an FPCB may be bonded to the pad 250 in the bonding area B.

Accordingly, physical touch information input to the touch sensor is converted into an electrical signal due to a difference in capacitance through the first sensing electrode 210 and the second sensing electrode 230, and the electrical signal is applied to the pad 250. For example, touch sensing may be implemented by being transmitted to the driving IC.

As described above, the FPCB may be bonded to the pad 250 through the bonding region B. For example, an intermediary structure such as an anisotropic conductive film (ACF) may be inserted between the pad 250 and the FPCB to perform a high temperature compression process. In this case, the pad 250 may be damaged by pressure, and the first protective layer 110 substantially provided as the base layer may be damaged and deformed together.

However, as described above, the first protective layer 110 has elastic modulus, thickness, and / or tensile strength characteristics so that changes in elastic modulus at high temperatures are suppressed, thereby providing improved shock absorption and high temperature reliability. Accordingly, it is possible to reduce or prevent damage such as cracking or peeling of the pad 250, thereby improving touch sensing reliability and sensitivity.

In some embodiments, as described with reference to FIG. 1, the second protective layer 130 may be formed on the electrode layer 120. For example, a portion of the second protective layer 130 may be removed to expose the pads 250 to perform the bonding process with the FPCB. The pressurization process may be performed while the FPCB partially overlaps with the upper surface of the second protective layer 130.

In this case, since the second protective layer 130 also has substantially the same or similar elasticity, thickness, and / or tensile strength characteristics as the first protective layer 110, the pads 250 are provided through improved shock absorption and high temperature stability. Can protect.

In some embodiments, the sensing electrodes included in the electrode layer 120 are provided as independent sensing domains, so that they can be driven in a self-capacitance method. In this case, traces may be extended from each sensing electrode to be connected to each pad.

3 to 6 are cross-sectional views illustrating a method of manufacturing a touch sensor according to example embodiments. Detailed description of materials described with reference to FIGS. 1 and 2 is omitted.

Referring to FIG. 3, the separation layer 100 and the first protective layer 110 may be sequentially formed on the carrier substrate 50.

As the carrier substrate 50, a glass substrate can be used, for example. Separation layer 100 is a slit coating, knife coating, spin coating, casting, micro gravure coating, gravure coating, bar coating, roll coating, wire bar coating, dip coating, spray coating, screen printing using the above-described polymer material, It can be formed through coating and / or printing processes such as gravure printing, flexo printing, offset printing, inkjet coating, dispenser printing, nozzle coating, capillary coating, and the like.

The first protective layer 110 may be formed through, for example, a baking process after the above-described curable resin composition is applied on the separation layer 100. The modulus and tensile strength of the first protective layer 110 may be controlled by adjusting the type and content of the curable resin and the crosslinking agent included in the curable resin composition, baking temperature, and time. According to exemplary embodiments, the first protective layer 110 may be formed to satisfy the above-described TD ² value range.

In some embodiments, the first protective layer 110 may be formed using an inorganic insulating material such as silicon oxide. In this case, the first protective layer 110 may be formed through a vapor deposition process such as chemical vapor deposition (CVD) or vacuum deposition.

Referring to FIG. 4, the electrode layer 120 may be formed on the first protective layer 110, and the second protective layer 130 may be formed on the electrode layer 120.

For example, a conductive film including a metal and / or a transparent conductive oxide may be formed on the first protective layer 110. The conductive film may be formed through, for example, a physical vapor deposition process such as a sputtering process, chemical vapor deposition, plasma deposition, thermal deposition, thermal oxidation, anodization, or cluster ion beam deposition.

Thereafter, the conductive layer may be etched to form an electrode layer 120 including sensing electrodes 210 and 230, traces 217 and 237 and pads 250 as shown in FIG. 2.

The second protective layer 130 may be formed through, for example, similar materials and processes substantially the same as or similar to the first protective layer 110. According to exemplary embodiments, the second protective layer 130 may also be formed to satisfy the above-described TD ² value.

In one embodiment, the second protective layer 130 may be formed to expose the pads 250 for the FPCB bonding process.

Referring to FIG. 5, a second protective film 155 may be formed on the second protective layer 130, and the carrier substrate 50 may be peeled off from the separation layer 100.

Accordingly, a stacked structure of the separation layer 100 and the first protective layer 120 is substantially provided as the substrate of the electrode layer 120 or the touch sensor, and a separate substrate may be omitted. Accordingly, a substantially thin touch sensor or film touch sensor of a substrate-less type may be provided.

Referring to FIG. 6, the first protective film 150 may be attached on the bottom surface of the separation layer 100.

The first and second protective films 150 and 155 may function as a release film. For example, when the touch sensor is applied to the image display device, the first and second protective films 150 and 155 may be removed.

In some embodiments, a bonding process for bonding the pads 250 and the FPCB to each other on the second protective layer 130 after removing the second protective film 155 may be further performed. During the bonding process, mechanical damage such as cracks and peeling of the pads 250 may be suppressed by improved elastic properties of the first and second protective layers 110 and 130.

7 is a schematic cross-sectional view illustrating a window stack and an image display device according to example embodiments.

Referring to FIG. 7, the window stack 350 may include the above-described touch sensor 300 and the window substrate 330.

The window substrate 330 includes, for example, a hard coating film, and in one embodiment, a light blocking pattern 335 may be formed on a peripheral portion of one surface of the window substrate 330. The light blocking pattern 335 may include, for example, a color print pattern, and may have a single layer or multi-layer structure. The bezel area or the non-display area of the image display device may be defined by the light blocking pattern 335.

For example, traces and pads included in the touch sensor 300 are disposed in the bezel area defined by the light blocking pattern 335, and are protected and protected by the first and second protective layers 110 and 130. Can be supported.

The window stack 350 may further include an optical layer 310. The optical layer 310 may include various optical films or optical structures included in the image display device, and may include a coated polarizer or polarizing plate in some embodiments. The coated polarizer may include a liquid crystal coating layer including a polymerizable liquid crystal compound and a dichroic dye. In this case, the optical layer 310 may further include an alignment layer for imparting alignment to the liquid crystal coating layer.

For example, the polarizing plate may include a polyvinyl alcohol-based polarizer and a protective film attached to at least one surface of the polyvinyl alcohol-based polarizer.

The optical layer 310 may be directly bonded to the one surface of the window substrate 330 or may be attached through the second point adhesive layer 320. In one embodiment, the optical layer 310 may be combined with the touch sensor 300 through the first point adhesive layer 325.

As illustrated in FIG. 7, the window substrate 330, the optical layer 310, and the touch sensor module 300 may be arranged in order from the user's viewing side. In this case, since the sensing electrodes of the touch sensor module 300 are disposed under the optical layer 310 including the polarizer or the polarizing plate, electrode visibility may be more effectively prevented.

The image display device according to example embodiments may include a display panel 460 and a window stack 350 stacked on the display panel 460.

The display panel 460 includes a pixel electrode 410, a pixel defining layer 420, a display layer 430, a counter electrode 440 and an encapsulation layer 450 disposed on the panel substrate 400. You can.

The panel substrate 400 may include glass or a flexible resin material, and when the flexible resin material is included, the image display device may be provided as a flexible display.

A pixel circuit including a thin film transistor (TFT) is formed on the panel substrate 400, and an insulating layer covering the pixel circuit may be formed. The pixel electrode 410 may be electrically connected to the drain electrode of the TFT, for example, on the insulating film.

The pixel defining layer 420 may be formed on the insulating layer to expose the pixel electrode 410 to define a pixel region. The display layer 430 is formed on the pixel electrode 410, and the display layer 430 may include, for example, a liquid crystal layer of a liquid crystal display (LCD) device or an organic light emitting layer of an organic light emitting diode (OLED) device. .

The counter electrode 440 may be disposed on the pixel defining layer 420 and the display layer 430. The counter electrode 440 may be provided as, for example, a common electrode or a cathode of the image display device. An encapsulation layer 450 for protecting the display panel 460 may be stacked on the counter electrode 440.

In some embodiments, the display panel 460 and the window stack 350 may be combined through the point adhesive layer 360. For example, the thickness of the point adhesive layer 360 may be greater than the thickness of each of the first and second point adhesive layers 320 and 325, and the viscoelasticity at -20 to 80 ° C may be about 0.2 MPa or less. In this case, noise from the display panel 460 can be shielded, and interfacial stress can be relaxed during bending to suppress damage to the window stacked body 350. In one embodiment, the viscoelasticity may be about 0.01 to 0.15MPa.

Hereinafter, characteristics of the touch sensor laminate of the present invention will be described in more detail through specific experimental examples. The examples included in the following experimental examples are only illustrative of the present invention and do not limit the scope of the appended claims, and various changes and modifications to the examples are possible within the scope of the present invention and technical thought. It is obvious to, and it is natural that such variations and modifications fall within the scope of the appended claims.

Examples and comparative examples

Soda lime glass having a thickness of 700 µm is used as a carrier substrate, and a separation layer composition containing melamine-based resin, cinnamate-based resin, and propylene glycol monomethyl ether acetate is coated on the carrier substrate to produce 100 Pre-baking at ~ 130 ° C for 2 minutes and post-baking at 150 ~ 180 ° C for 5 minutes to form a separation layer (thickness: 300nm).

On the separation layer, a curable resin composition containing 30 parts by weight of an epoxy resin, 20 parts by weight of a COP resin, 1 part by weight of EPHE-3150CE (manufactured by Dicel) as a curing agent, and diethyl glycol glycol methyl ethyl ether as a solvent was applied. . Thereafter, the applied film was prebaked at 110 ° C for 2 minutes in a convection oven. Thereafter, the post-baking was performed at 230 ° C for 30 minutes to form a 3 μm-thick protective layer.

The tensile modulus at 25 ° C and 140 ° C of the protective layer was measured, respectively, and the rate of change in elastic modulus at 140 ° C was calculated. Specifically, the tensile modulus was measured according to the method of ASTM D638 using Shimazdu AG-X equipment. The tensile strength of the protective layer was measured according to the method of ASTM D638 using AG-X equipment of Shimazdu.

Thereafter, after depositing ITO on the protective layer to a thickness of 45 nm at a temperature of 25 ° C., an ITO layer was annealed at 230 ° C. for 30 minutes to form a bonding pad to prepare a touch sensor sample according to Example 1.

Example 2

A touch sensor sample was prepared through the same process as in Example 1, except that the thickness of the protective layer was 2 μm.

Example 3

A touch sensor sample was prepared through the same process as in Example 1, except that 20 parts by weight of the epoxy resin and 20 parts by weight of the COP resin were used in the curable resin composition, and the thickness of the protective layer was 6 μm.

Comparative Example 1

A touch sensor sample was prepared through the same process as in Example 1, except that 20 parts by weight of the epoxy resin and 20 parts by weight of the COP resin were used as the curable resin, and the thickness of the protective layer was 1 μm.

Comparative Example 2

A touch sensor sample was prepared through the same process as in Example 1, except that 25 parts by weight of the epoxy resin and 10 parts by weight of the COP resin were used as the curable resin, and the thickness of the protective layer was 2 μm.

Comparative Example 3

A touch sensor sample was prepared through the same process as in Example 1, except that 20 parts by weight of the epoxy resin and 20 parts by weight of the COP resin were used as the curable resin and the thickness of the protective layer was 2 μm.

Comparative Example 4

A touch sensor sample was prepared through the same process as in Example 1, except that 25 parts by weight of the epoxy resin and 10 parts by weight of the COP resin were used as the curable resin and the thickness of the protective layer was 9 μm.

Bonding pad crack evaluation

A pressing process was performed for 10 seconds at a pressure of 1 MPa at 140 ° C using FPCB on the bonding pads of the touch sensor samples of Examples and Comparative Examples. After the pressing process, it was evaluated as "○" when no crack was observed on the bonding pad and "X" when crack was observed.

Table 1 shows the evaluation results.

Example 1 Example 2 Example 3 Comparative Example 1 Comparative Example 2 Comparative Example 3 Comparative Example 4 Protective layer
Thickness (D: μm) 3 2 6 One 2 2 9 Protective layer
Modulus of elasticity
(T: MPa) 25 ^o C 1452 1452 1100 1100 1220 1100 1220 140 ^o C 1363 1363 1020 26 520 26 520 Modulus of elasticity change (%) 6.1 6.1 7.2 97.6 57.4 97.6 57.4 TD ² (MPa * ㎛ ² ) 1.3 × 10 ⁴ 5.8 × 10 ³ 3.9 × 10 ⁴ 1.1 × 10 ³ 4.8 × 10 ³ 4.4 × 10 ³ 9.8 × 10 ⁴ Protective layer tensile strength
(I: N / mm ² ) 50 40 45 90 10 150 50 I / D (N / mm ² * ㎛) 16.6 20 7.5 90 5 75 5.5 Protective layer Tg ( ^o C) 201 201 178 130 75 70 125 Cracking ○ ○ ○ × × × ×

Referring to Table 1, in the case where the protective layer satisfying the TD ² value according to the exemplary embodiments is formed, the rate of change of the elastic modulus is suppressed to less than 10%, and pad cracking does not substantially occur even in a high temperature bonding process. .

100: separation layer 110: first protective layer
120: electrode layer 130: second protective layer
150: first protective film 155: second protective film
210: first sensing electrode 215: bridge electrode
217: first trace 230: second sensing electrode
237: second trace 250: pad

Claims (17)

Separation layer;
A first protective layer formed on the separation layer; And
A touch sensor disposed on the first protective layer and including an electrode layer including sensing electrodes, wherein the first protective layer satisfies Expression 1 below:
[Equation 1]
5.2 × 10 ³ MPa * ㎛ ² ≤TD ² ≤5.2 × 10 ⁴ MPa * ㎛ ²
(In Formula 1, T represents the modulus of elasticity (MPa) at 25 ° C of the first protective layer, and D represents the thickness (µm) of the first protective layer).
The touch sensor according to claim 1, wherein the rate of change of the elastic modulus defined by the following Equation 2 of the first protective layer is 15% or less:
[Equation 2]
Modulus of elasticity change (%) = {(25 ° C modulus-140 ° C modulus) / (25 ° C modulus)} × 100.
The touch sensor according to claim 1, wherein the first protective layer has an elastic modulus at 25 ° C of 1000 to 2500 MPa.
The method according to claim 1, The thickness of the first protective layer is 0.5 to 10㎛, touch sensor.
The method according to claim 1, The tensile strength of the first protective layer is 30 to 60 N / mm ² , the touch sensor.
The touch sensor according to claim 1, wherein the first protective layer satisfies Expression 3 below:
[Equation 3]
5 N / mm ² * ㎛≤I / D ≤25 N / mm ² * ㎛
(In formula 3, I represents the tensile strength (N / mm ² ) of the first protective layer, and D represents the thickness (µm) of the protective layer).
The touch sensor according to claim 1, wherein the glass transition temperature of the first protective layer is 150 to 210 ° C.
The touch sensor according to claim 1, further comprising a second protective layer formed on the electrode layer, wherein the second protective layer satisfies Equation 1.
The touch sensor according to claim 1, wherein the first protective layer is formed from a curable resin composition.
Forming a separation layer on the carrier substrate;
Forming a first protective layer satisfying the following Equation 1 on the separation layer;
Forming an electrode layer including sensing electrodes on the first protective layer; And
A method of manufacturing a touch sensor, comprising peeling the carrier substrate from the separation layer:
[Equation 1]
5.2 × 10 ³ MPa * ㎛ ² ≤TD ² ≤5.2 × 10 ⁴ MPa * ㎛ ²
(In Formula 1, T represents the modulus of elasticity (MPa) at 25 ° C of the first protective layer, and D represents the thickness (µm) of the first protective layer).
The method of claim 10, wherein forming the electrode layer comprises forming traces electrically connected to the sensing electrodes and pads connected to ends of the traces.
The method of claim 11, further comprising heat-pressing the pads and a flexible circuit board (FPCB).
The method for manufacturing a touch sensor according to claim 12, wherein a rate of change in elastic modulus defined by the following Equation 2 of the first protective layer is 15% or less.
[Equation 2]
Modulus of elasticity change (%) = {(25 ° C modulus-140 ° C modulus) / (25 ° C modulus)} × 100.
Window substrates; And
A window stack comprising the touch sensor according to any one of claims 1 to 9.
The window stack according to claim 14, further comprising an optical layer disposed between the window substrate and the touch sensor.
Display panel; And
An image display device, which is stacked on the display panel and includes a touch sensor according to any one of claims 1 to 9.
The image display apparatus of claim 16, further comprising a point adhesive layer bonding the display panel and the touch sensor to each other.

Images