KR102526899B1 - Touch sensor and image display device including the same - Google Patents

Abstract

The touch sensor of the embodiments of the present invention is arranged in a row direction on the substrate layer, first sensing electrodes having protrusions formed on both ends in the row direction, and arranged in a column direction on the substrate layer and at both ends in the column direction and second sensing electrodes integrally connected to each other by connection parts formed in the first and second sensing electrodes, and bridge electrodes electrically connected to neighboring protrusions in a row direction. The protrusions are spaced apart so as to face each other with a connecting portion interposed therebetween, and the connecting portion includes a recess. Visibility of the electrodes may be reduced in an intersection area of the sensing electrodes through the protrusion and the recess.

Description

Touch sensor and image display device including the same {TOUCH SENSOR AND IMAGE DISPLAY DEVICE INCLUDING THE SAME}

The present invention relates to a touch sensor and an image display device including the same. More specifically, it relates to a touch sensor including a plurality of conductive layers and an image display device including the same.

Recently, as information technology develops, demands for the display field are presented in various forms. For example, various flat panel display devices having characteristics such as thinning, light weight, and low power consumption, such as liquid crystal display devices, plasma display devices, An electro luminescent display device, an organic light-emitting diode display device, and the like are being researched.

On the other hand, a touch panel or touch sensor, which is an input device that is attached to the display device and allows a user's command to be input by selecting instructions displayed on the screen with a person's hand or an object, is combined with the display device to provide an image display function and Electronic devices implemented together with an information input function are being developed.

The touch sensor includes sensing electrodes for converting a touch input from a user into an electrical signal through capacitance change. Since the sensing electrodes are disposed within the display area of the image display device, when the sensing electrodes are recognized by a user, image quality implemented from the image display device may be deteriorated.

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 recently been developed. However, it is necessary to design a sensing electrode to suppress a visibility phenomenon without deteriorating electrical characteristics and sensing sensitivity of the touch sensor.

Korean Patent Publication No. 2014-0092366

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

One object of the present invention is to provide an image display device including a touch sensor having improved optical and electrical characteristics.

One object of the present invention is to provide a window laminate including a touch sensor having improved optical and electrical characteristics.

1. Base layer; first sensing electrodes arranged in a row direction on the base layer and having protrusions formed at both ends in the row direction; second sensing electrodes arranged in a column direction on the base layer and integrally connected to each other by connection parts formed at both ends in the column direction; and bridge electrodes electrically connected to the adjacent protrusions in the row direction, wherein the protrusions are spaced apart from each other to face each other with the connection portion interposed therebetween, and the connection portion includes a recess.

2. The touch sensor according to 1 above, wherein the protrusion is inserted into the recess.

3. In the above 2, the connection part includes a first portion adjacent to both ends of the second sensing electrode, and a second portion having a reduced width than the first portion by the recess, the touch sensor .

4. In the above 3, the length of the recess in the column direction is 70 to 200 ㎛, the touch sensor.

5. In the above 3, the width of the second portion is 50 to 150㎛, the touch sensor.

6. The touch sensor according to 1 above, further comprising an insulating layer at least partially covering the first sensing electrodes and the second sensing electrodes on the base layer.

7. The touch sensor according to 6 above, wherein the bridge electrode crosses the recess on the insulating layer.

8. The touch sensor according to 7 above, wherein the bridge electrode includes a contact directly contacting the protruding portion of the first sensing electrode through the insulating layer.

9. The touch sensor according to 1 above, wherein the protruding portion and the corner portions of the connecting portion have a rounded shape.

10. The touch sensor according to 1 above, wherein corner portions of the bridge electrode have a rounded shape.

11. window substrate; and the touch sensor of any one of 1 to 10 above stacked on the window substrate.

12. The window laminate according to 11 above, further comprising a polarization layer disposed between the window substrate and the touch sensor or on the touch sensor.

13. display panel; and the touch sensor of any one of 1 to 10 stacked on the display panel.

In the touch sensor according to the embodiments of the present invention, for example, by adjusting the pattern shape of the intersection area of the column-direction sensing electrodes and the row-direction sensing electrodes, the electrode visibility phenomenon due to overlapping electrode patterns in the intersection area is suppressed. can do.

In some embodiments, the electrode visibility phenomenon may be additionally suppressed by rounding the pattern shape in the intersection area.

1 is a schematic plan view illustrating an example of an electrode arrangement of a capacitive type touch sensor.
2 and 3 are a plan view and a cross-sectional view respectively illustrating a cross-region structure of a touch sensor according to exemplary embodiments.
4 is a plan view illustrating a cross-region structure of a touch sensor according to some exemplary embodiments.
5 is a schematic diagram illustrating a window laminate and an image display device according to exemplary embodiments.
6 and 7 are graphs illustrating channel resistance measurement results according to a change in width of a connection part.
8 is a graph showing a channel resistance measurement result according to a change in the length of a recess included in a connection part.

Embodiments of the present invention provide a touch sensor including a protrusion and a recess in an intersection area of sensing electrodes and suppressing electrode visibility. In addition, a window laminate and an image display device including the touch sensor are provided.

With reference to the following drawings, embodiments of the present invention will be described in more detail. However, the following drawings attached to this specification 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 above-described invention, so the present invention is described in such drawings should not be construed as limited to

The terms "column direction" and "row direction" used in this application are used relatively to refer to two directions that cross each other, and do not refer to two absolute directions.

1 is a schematic plan view illustrating an example of an electrode arrangement of a capacitive type touch sensor.

Referring to FIG. 1 , the touch sensor may include, for example, first sensing electrodes 50 and second sensing electrodes 60 disposed on a base layer 100 .

The base layer 100 is used to encompass a support layer for forming the sensing electrodes 50 and 60, an interlayer insulating layer, or a film-type substrate. For example, the substrate layer 100 may be a film material commonly used in a touch sensor without particular limitation, and may include, for example, glass, polymer, and/or inorganic insulating material. Examples of the polymer include cyclic olefin polymer (COP), polyethylene terephthalate (PET), polyacrylate (PAR), polyetherimide (PEI), polyethylene naphthalate (PEN), polyphenylene sulfide (PPS), poly Allylate (polyallylate), polyimide (PI), cellulose acetate propionate (CAP), polyethersulfone (PES), cellulose triacetate (TAC), polycarbonate (PC), cyclic olefin copolymer (COC), poly Methyl methacrylate (PMMA) etc. are mentioned. Examples of the inorganic insulating material include silicon oxide, silicon nitride, silicon oxynitride, and metal oxide.

In some embodiments, a layer or film member of an image display device into which the touch sensor is inserted may be provided as the substrate layer 100 . For example, an encapsulation layer or a passivation layer included in a display panel may be provided as the base layer 100 .

The first sensing electrodes 50 and the second sensing electrodes 60 may be arranged along two different crossing directions. For example, the first sensing electrodes 50 may be arranged along the row direction (or X direction) of the upper surface of the base layer 100 . The second sensing electrodes 60 may be arranged along the column direction (or Y direction) of the upper surface of the base layer 100 .

Second sensing electrodes 60 adjacent along the column direction may be connected to each other by a connection part 65 . The connecting portion 65 may be integrally connected to the second sensing electrodes 60 and provided as a substantially single member.

A plurality of second sensing electrodes 60 may be integrally connected to each other by the connection part 65 to define a second sensing electrode column. Also, a plurality of second sensing electrode columns may be disposed along the row direction.

Each of the first sensing electrodes 50 may have an independent island pattern shape. First sensing electrodes 50 neighboring in the row direction may be electrically connected to each other through a bridge electrode 55 .

Accordingly, a first sensing electrode row including a plurality of first sensing electrodes 50 connected to each other through the bridge electrode 55 may be defined. Also, a plurality of first sensing electrode rows may be disposed along the column direction.

The first and second sensing electrodes 50 and 60 and/or the bridge electrode 55 may be, for example, indium tin oxide (ITO), indium zinc oxide (IZO), zinc oxide (ZnO), indium zinc tin A transparent conductive oxide such as oxide (IZTO) or cadmium tin oxide (CTO), a transparent conductive material such as silver nanowire (AgNW), carbon nanotube (CNT), graphene, metal mesh, or conductive polymer may be included.

In some embodiments, the bridge electrode 55 is 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), molybdenum ( Mo), calcium (Ca), or an alloy thereof.

In some embodiments, the first and second sensing electrodes 50 and 60 and/or the bridge electrode 55 may include a stacked structure of a transparent conductive oxide layer and a metal layer.

In some embodiments, the bridge electrode 55 may be formed to include a low-resistance metal to reduce channel resistance through the first sensing electrode row. In some embodiments, the first and second sensing electrodes 50 and 60 may include the above-described transparent conductive oxide to improve transmittance of the touch sensor.

Traces may branch and extend from each of the first sensing electrode row and the second sensing electrode column. For example, a first trace 70 may extend from each of the first sensing electrode rows, and a second trace 80 may extend from each of the second sensing electrode columns.

End portions of the first and second traces 70 and 80 may be gathered in a bonding area allocated to one end of the base layer 100 . The end portions may be bonded through, for example, a flexible printed circuit board (FPCB) and an anisotropic conductive film (ACF). The touch sensor driving IC chip may be electrically connected to the first and second traces 70 and 80 through the flexible printed circuit board.

The first and second trace electrodes 70 and 80 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), molybdenum (Mo), calcium (Ca), or an alloy thereof (eg, silver-palladium-copper (APC)). These may be used alone or in combination of two or more.

In an intersection area C indicated by a dotted line in FIG. 1 , the bridge electrode 55 and the connection portion 65 may cross and overlap each other in a planar direction. In addition, as shown in FIG. 3 , the bridge electrode 55 and the connection portion 65 may face each other with the insulating layer 120 interposed therebetween.

Therefore, in the intersection area C, for example, an increase in interfacial reflection due to a difference in refractive index between layers and a difference in color may cause the user to perceive the electrode.

2 and 3 are a plan view and a cross-sectional view respectively illustrating a cross-region structure of a touch sensor according to exemplary embodiments. Specifically, FIG. 3 is a cross-sectional view taken in the thickness direction along line II' of FIG. 2 .

Referring to FIGS. 2 and 3 , as described with reference to FIG. 1 , the first sensing electrodes 110 are physically connected to each other with a connection portion 135 integrally connected to the second sensing electrodes 130 interposed therebetween. can be separated The bridge electrode 115 may cross the connection portion 135 on the insulating layer 120 and overlap in a planar direction.

According to example embodiments, protrusions 112 may be formed at both ends of the first sensing electrode 110 in the row direction. The protruding parts of the neighboring first sensing electrodes 110 may be spaced apart from each other in the row direction to face each other.

The second sensing electrodes 130 may be integrally connected through connection parts 135 formed at both ends in the column direction. According to example embodiments, the connecting portion 135 may include a recess 132 concave in the row direction.

As shown in FIG. 2 , a pair of recesses 132 facing each other in the row direction may be formed in one connection part 135 . The connecting portion 135 may include a central portion whose width is reduced by the recesses 132 .

For example, the connection part 135 may include a first part 135a and a second part 135b. The first part 135a may include both ends directly connected to the second sensing electrode 130 among the connection parts 135 . The second portion 135b may include a portion narrowed in width by the recess 132 . According to example embodiments, a pair of first parts 135a may be connected to both ends of the second part 135b.

In some embodiments, the protruding part 112 included in the first sensing electrode 110 may be inserted into the recess 132 included in the connection part 135 of the second sensing electrode 130 . A pair of protrusions 112 adjacent in the row direction may face each other with a connecting portion 135 or a second portion 135b interposed therebetween.

The insulating layer 120 may at least partially cover the first and second sensing electrodes 110 and 130 . The bridge electrode 115 may electrically connect first sensing electrodes 110 adjacent to each other in the row direction on the insulating layer 120 .

As shown in FIG. 3 , the bridge electrode 115 may include a contact 115a penetrating the insulating layer 120 and contacting the first sensing electrode 110 . According to example embodiments, the contact 115a included in the bridge electrode 115 may directly contact the upper surface of the protrusion 112 of the first sensing electrode 110 .

A passivation layer 140 covering the bridge electrode 115 may be formed on the insulating layer 120 . The insulating layer 120 and the passivation layer 140 may include an organic insulating material such as a siloxane-based resin or an acrylic resin, or an inorganic insulating material such as silicon oxide, silicon nitride, or silicon oxynitride.

As described above, the protrusion 112 of the first sensing electrode 110 and the recess 132 or the second portion 135b of the second sensing electrode 130 are formed in the intersection area C shown in FIG. 1 . Through this, the area occupied by the electrode can be reduced. Accordingly, it is possible to reduce or suppress the electrode visibility phenomenon caused in the intersection area (C).

In addition, the length of the bridge electrode 115 may be reduced by reducing the distance between the protrusions 112 through the recess 132 . Therefore, it is possible to suppress or reduce the visibility of the electrode due to the overlapping of the electrode layers.

In the connection portion 135 , an excessive increase in channel resistance in the second sensing electrode column due to the second portion 135b may be prevented by relatively increasing the area of the first portion 135a.

Therefore, it is possible to reduce the overlapping area or size of the electrodes in the crossing area C to suppress electrode visibility and prevent an increase in channel resistance, thereby maintaining an appropriate signal transmission speed.

Referring back to FIG. 2 , the width (b) of the second portion 135b of the connection portion 135 may be smaller than the width (a) of the first portion 135a of the connection portion 135 . In some embodiments, a width (width in a row direction) (b) of the second portion 135b of the connecting portion 135 may be about 50 μm to about 150 μm. For example, when the width of the second portion 135b is less than about 50 μm, channel resistance of the second sensing electrode row may excessively increase. When the width of the second portion 135b exceeds about 150 μm, it may not be easy to implement the above-described electrode visibility prevention effect, and the channel resistance reduction effect may also be weakened. In one embodiment, the width of the second portion 135b may be about 50 to 100 μm.

In some embodiments, the length (length in the column direction) (c) of the recess 132 may be about 70 to 200 μm. When the length of the recess 132 is less than about 70 μm, the width of the protruding portion 112 is also excessively reduced, so that the channel resistance of the first sensing electrode row may excessively increase. In addition, since a sufficient distance between the protruding portion 112 and the connecting portion 132 is not secured, mutual signal interference may occur.

When the length of the recess 132 exceeds about 200 μm, the length of the second sensing electrode column may increase excessively, resulting in an increase in channel resistance.

Preferably, the length of the recess 132 may be about 100 to 200 μm.

4 is a plan view illustrating a cross-region structure of a touch sensor according to some exemplary embodiments.

Referring to FIG. 4 , corners of the recess 132 formed in the connection portion 137 of the protruding portion 113 included in the first sensing electrode 110 and the second sensing electrode 135 may have a rounded shape. there is. Accordingly, corner portions of the first portion 137a and the second portion 137b of the connecting portion 137 may also have a rounded shape.

As the corner portions of the electrode are rounded, it is possible to additionally suppress the visibility of the electrode due to a rapid pattern profile change. In addition, as the rounded profile is introduced, the moiré effect due to overlapping of the electrodes and wires of the display panel on which the touch sensor is mounted can be reduced.

In some embodiments, corner portions of the bridge electrode 117 may also be rounded, and the above-described electrode visibility prevention and moiré prevention may be more effectively implemented.

5 is a schematic diagram illustrating a window laminate and an image display device according to exemplary embodiments.

Referring to FIG. 5 , a window laminate 250 may include a window substrate 230, a polarization layer 210, and a touch sensor 200 according to the above-described exemplary embodiments.

The window substrate 230 includes, for example, a hard coating film, and in one embodiment, a light blocking pattern 235 may be formed on a peripheral portion of one surface of the window substrate 230 . The light-blocking pattern 235 may include, for example, a color printed pattern, and may have a single layer or multi-layer structure. A bezel area or a non-display area of the image display device may be defined by the light blocking pattern 235 .

The polarization layer 210 may include a coated polarizer or polarizer. The coating type polarizer may include a liquid crystal coating layer including a polymerizable liquid crystal compound and a dichroic dye. In this case, the polarization layer 210 may further include an alignment film 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 polarization layer 210 may be directly bonded to the one surface of the window substrate 230 or attached through the first adhesive layer 220 .

The touch sensor 200 may be included in the window laminate 250 in the form of a film or panel. In one embodiment, the touch sensor 200 may be coupled to the polarization layer 210 through the second adhesive layer 225 .

As shown in FIG. 5 , the window substrate 230 , the polarization layer 210 , and the touch sensor 200 may be disposed sequentially from the user's viewing side. In this case, since the electrode layer of the touch sensor 200 is disposed under the polarization layer 210 , it is possible to prevent electrode visibility. In addition, the electrode visibility phenomenon can be more effectively prevented through the above-described electrode structure in the intersection area C.

In one embodiment, the touch sensor 200 may be directly transferred onto the window substrate 230 or the polarization layer 210 . In one embodiment, the window substrate 230, the touch sensor 200, and the polarization layer 210 may be arranged sequentially from the user's viewing side.

The image display device may include a display panel 360 and the aforementioned window laminate 250 coupled to the display panel 360 .

The display panel 360 may include a pixel electrode 310, a pixel defining layer 320, a display layer 330, a counter electrode 340, and an encapsulation layer 350 disposed on a panel substrate 300. can

A pixel circuit including a thin film transistor (TFT) may be formed on the panel substrate 300, and an insulating film covering the pixel circuit may be formed. The pixel electrode 310 may be electrically connected to, for example, a drain electrode of a TFT on the insulating film.

The pixel defining layer 320 may be formed on the insulating layer to expose the pixel electrode 310 to define a pixel area. A display layer 330 is formed on the pixel electrode 310 , and the display layer 330 may include, for example, a liquid crystal layer or an organic emission layer.

A counter electrode 340 may be disposed on the pixel defining layer 320 and the display layer 330 . The counter electrode 340 may be provided as, for example, a common electrode or cathode of an image display device. An encapsulation layer 350 for protecting the display panel 360 may be stacked on the opposite electrode 340 .

In some embodiments, the display panel 360 and the window laminate 250 may be coupled through an adhesive layer 260 . For example, the thickness of the adhesive layer 260 may be greater than the thickness of each of the first and second adhesive layers 220 and 225, and may have a viscoelasticity of about 0.2 MPa or less at -20 to 80 °C. In this case, noise from the display panel 360 may be shielded, and damage to the window stack 250 may be suppressed by relieving interfacial stress during bending. In one embodiment, the viscoelasticity may be about 0.01 to 0.15 MPa.

Hereinafter, experimental examples including preferred embodiments are presented to aid understanding of the present invention, but these examples are only illustrative of the present invention and do not limit the scope of the appended claims, and the scope and technical spirit of the present invention It is obvious to those skilled in the art that various changes and modifications to the embodiments are possible within the scope, and it is natural that these changes and modifications fall within the scope of the appended claims.

Experimental Example 1: Measurement of channel resistance according to the width of the connection part (second part)

First sensing electrodes and second sensing electrodes having a size of 4 mm x 4 mm for each unit electrode were formed on the COP substrate. The second sensing electrodes are integrally connected by a connection part, and a recess is formed in the connection part to include a narrowed second part as shown in FIG. 2 . The first sensing electrodes are formed to include protrusions facing each other with the second part interposed therebetween. The sensing electrode was formed using ITO with a sheet resistance of 40Ω/□.

An insulating layer covering the first and second sensing electrodes was formed, and a bridge electrode was formed to connect adjacent first sensing electrodes. Specifically, a contact hole having a size of 30 μm x 30 μm penetrating the insulating layer was formed, and a conductive layer filling the contact hole was deposited and patterned on the insulating layer to form a bridge electrode.

Channel resistances through the first sensing electrode row and the second sensing electrode row of the touch sensor fabricated as described above were respectively measured.

6 and 7 are graphs illustrating channel resistance measurement results according to a change in width of a connection part.

Specifically, FIG. 6 shows that a bridge electrode having a width of 60 μm is formed using ITO having a sheet resistance of 40 Ω/□, and the width (a) of the first part included in the connection part of the second sensing electrode is 250 μm, and the recess When the length (c) is fixed to 90 μm, the change in channel resistance according to the change in the width (b) of the second portion is shown. FIG. 7 shows channel resistance results under the same conditions as those in FIG. 6 except that the bridge electrode was formed with a width of 4 μm using a metal having a sheet resistance of 0.2 Ω/□.

6 and 7, while the channel resistance (x resistance) through the first sensing electrode row remains constant, while the width of the second part exceeds about 50 μm, the channel resistance through the second sensing electrode column ( It can be seen that the increasing trend of y resistance) is gradual.

Experimental Example 2: Measurement of channel resistance according to recess length

8 is a graph showing a channel resistance measurement result according to a change in the length of a recess included in a connection part.

Specifically, in a state in which the sensing electrodes and the ITO bridge electrode are formed with the same material and size as in Experimental Example 1, and the width (a) of the first part is fixed to 250 μm and the width (b) of the second part is fixed to 75 μm A change in channel resistance was measured while changing the length (c) of the recess. The width of the protrusion included in the first sensing electrode was increased at the same rate as the length of the recess was changed.

Referring to FIG. 8 , it can be seen that as the length of the recess increases to about 70 μm or more, increases and decreases in the resistance of the first and second sensing electrodes cancel each other out, thereby suppressing an increase in total resistance. When the length of the recess was about 100 μm or more, the total resistance remained substantially constant.

As described with reference to FIGS. 6 to 8 , it was confirmed that electrode visibility can be prevented while suppressing an increase in channel resistance through size adjustment of the connecting portion and the recess.

100: base layer 110: first sensing electrode
115: bridge electrode 120: insulating layer
130: second sensing electrode 132: recess
135: connection part 135a: first part
135b second portion 140 passivation layer

Claims (13)

base layer;
first sensing electrodes arranged in a row direction on the base layer and having protrusions formed at both ends in the row direction;
second sensing electrodes arranged in a column direction on the base layer and integrally connected to each other by connection parts formed at both ends in the column direction; and
including bridge electrodes electrically connected to the protrusions adjacent to each other in the row direction;
The protrusions are spaced apart to face each other with the connecting portion interposed therebetween, the connecting portion including a recess,
the connection part
a first portion adjacent to both ends of the second sensing electrode; and
A second portion having a width reduced than that of the first portion by the recess, the first portion having a larger width than the second portion as a whole,
The touch sensor according to claim 1 , wherein the projection is inserted into the recess.
delete delete The touch sensor according to claim 1, wherein a length of the recess in the column direction is 70 to 200 μm.
The touch sensor according to claim 1, wherein the second portion has a width of 50 to 150 μm.
The touch sensor according to claim 1, further comprising an insulating layer at least partially covering the first sensing electrodes and the second sensing electrodes on the base layer.
The touch sensor according to claim 6 , wherein the bridge electrode crosses the recess on the insulating layer.
The touch sensor according to claim 7 , wherein the bridge electrode includes a contact directly contacting the protruding portion of the first sensing electrode through the insulating layer.
The touch sensor according to claim 1, wherein corners of the protruding portion and the connecting portion have a rounded shape.
The touch sensor according to claim 1, wherein corner portions of the bridge electrode have a rounded shape.
window substrate; and
A window laminate comprising the touch sensor of any one of claims 1 and 4 to 10 laminated on the window substrate.
The window laminate according to claim 11 , further comprising a polarization layer disposed between the window substrate and the touch sensor or on the touch sensor.
display panel; and
An image display device comprising the touch sensor of any one of claims 1 and 4 to 10 stacked on the display panel.

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