JP2022135862A - Laminated structure and touch sensor using the same - Google Patents

Abstract

To provide a laminated structure which is improved so as to overcome a problem of a conventional laminated structure having a tendency such that a protective layer formed of a non-conductive resin prevents high contact impedance and low electrostatic discharge (ESD).SOLUTION: A laminated structure 10 includes a base material 11, a silver nanowire layer 12 provided above the base material 11, and a metal layer 13 provided above the silver nanowire layer 12. The silver nanowire layer 12 includes a plurality of silver nanowires, and an indium tin oxide (ITO) coated on the plurality of silver nanowires. The total thickness of the silver nanowire layer 12 is 2.35-24 times of the thickness of the ITO.SELECTED DRAWING: Figure 1

Description

TECHNICAL FIELD The present disclosure relates to laminated structures, and more particularly to laminated structures including silver nanowire layers. The present disclosure also relates to touch sensors, and more particularly to touch sensors including the laminated structure described above.

Laminated structures comprising silver nanowires and metal layers can be applied to fabricate touch sensors. Patent Literature 1 discloses a laminated structure including metal nanowires. Conventionally, the surface of the silver nanowires in the laminated structure is covered with a protective layer made of non-conductive resin, which mainly protects the silver nanowires from scratches and peeling, It is used to enhance the adhesion between the structural substrate and the silver nanowires. Since this protective layer will be permanently attached to the surface of the substrate and silver nanowires, the protective layer should have high transparency, low haze, and It must have some optical properties such as low b*.

Furthermore, since the protective layer is permanently attached to the surface of the silver nanowires, the thickness of the protective layer plays an important factor in the efficiency of etching the silver nanowires during the etching process. In addition, since the protective layer is made of resin, it often requires an etchant with high etching selectivity. Furthermore, since the protective layer is formed of a non-conductive resin, it tends to have high contact impedance and poor electrostatic discharge (ESD) prevention properties.

China Patent No. 101689568

It is an object of the present disclosure to provide an improved laminate to overcome the problems of conventional laminate structures in which protective layers formed of non-conductive resins tend to provide high contact impedance and low electrostatic discharge (ESD) protection. The object is to provide a structure and a touch sensor including the same.

To achieve at least the above objectives, a laminate structure according to the present disclosure includes:
Base material;
a silver nanowire layer provided on top of the substrate; and a metal layer provided on top of the silver nanowire layer;
wherein said silver nanowire layer comprises:
a plurality of silver nanowires; and indium tin oxide (ITO) coated on said plurality of silver nanowires; and wherein a total thickness of said silver nanowire layer is 2.35 to 24 times the thickness of said ITO. has a thickness of

In the laminated structure, the total thickness of the silver nanowire layer can be in the range of 40-120 nm.

In the laminated structure, the thickness of the ITO included in the silver nanowire layer may be in the range of 5 to 17 nm.

In the laminated structure, the silver nanowire layer has a sheet resistance in the range of 5-100 ohms/square (ops).

The laminate structure can further include:
a second silver nanowire layer provided under the substrate; and a second metal layer provided under the second silver nanowire layer;
wherein said second silver nanowire layer comprises:
a plurality of silver nanowires; and indium tin oxide (ITO) coated on said plurality of silver nanowires; and wherein the total thickness of said second silver nanowire layer is equal to said It has a thickness of 2.35 to 24 times that of ITO.

To achieve at least the above objects, a touch sensor according to the present disclosure includes the above laminated structure.

In the above touch sensor, the silver nanowire layers and metal layers of the laminate structure can be patterned.

The touch sensor can include two layers of the stack, and all silver nanowire layers and metal layers of the stack can be patterned.

In the above touch sensor, the silver nanowire layer, the second silver nanowire layer, the metal layer, and the second metal layer in the laminated structure can all be patterned.

The laminated structures and touch sensors of the present disclosure exhibit reduced contact impedance, good ESD protection, and upgrade tolerance in reliability analysis (RA) without adversely affecting their optical requirements.

1 is a schematic cross-sectional view of a laminated structure according to a first embodiment of the present disclosure; FIG. FIG. 2 is a schematic cross-sectional view of a laminated structure according to a second embodiment of the present disclosure; FIG. 3 is a pictorial flowchart showing the manufacturing process (steps) of the touch sensor according to the third embodiment of the present disclosure. FIG. 4 is an image flow chart showing the manufacturing process of the touch sensor according to the fourth embodiment of the present disclosure. FIG. 5 is an image flow chart showing the manufacturing process of the touch sensor according to the fifth embodiment of the present disclosure.

To facilitate comprehension of the objects, features and advantages of the present disclosure, embodiments are provided along with accompanying drawings for detailed description of the present disclosure. Those skilled in the art can appreciate the advantages and benefits of the present disclosure from the content herein. While this disclosure may be practiced or applied in other embodiments, and many changes and modifications in the described embodiments can be made without departing from the spirit of this disclosure, the preferred embodiments are illustrative. It is also understood that this is merely an illustration and is not intended to limit this disclosure in any way.

In this specification and the appended claims, use of the word "a" or "the" in the singular shall be construed to include the plural unless the context dictates otherwise. be.

In this specification and the appended claims, the use of the term "or" includes the meaning of "and/or" unless the context dictates otherwise.

(First embodiment)
FIG. 1 is a schematic cross-sectional view of a laminate structure 10 according to a first embodiment of the disclosure. As shown, the laminated structure 10 in the first embodiment includes a substrate 11, a silver nanowire layer 12 provided on top of the substrate 11, and a metal layer 13 provided on top of the silver nanowire layer 12. including. The silver nanowire layer 12 includes a plurality of silver nanowires and indium tin oxide (ITO) coated on the plurality of silver nanowires.

In the laminated structure 10 according to the first embodiment, the total thickness of the silver nanowire layer 12 is eight times the thickness of the ITO (eg, 40 nm:5 nm). However, it is understood that the disclosure is not so limited. In some embodiments, the silver nanowire layer 12 is 2.35 to 24 times thicker than the ITO. As used herein, the term "total thickness of the silver nanowire layer" means the total thickness of the silver nanowire layer 12, including the thickness of the multiple silver nanowires and the thickness of the ITO.

In the laminated structure 10 according to the first embodiment, the base material 11 is made of polyethylene terephthalate (PET). Other materials suitable for substrate 11 include, but are not limited to, cyclic olefin copolymer (COP), colorless polyimide (CPI), and ultra thin glass (UTG).

In the laminated structure 10 according to the first embodiment, the total thickness of the silver nanowire layers 12 is 40 nm. However, the present disclosure is not so limited, and in some embodiments, the overall thickness of silver nanowire layer 12 has a thickness in the range of 40-120 nm.

In the laminated structure 10 according to the first embodiment, the silver nanowire layer 12 has a controlled sheet resistance of 50 ohms/square (ops). However, the present disclosure is not specifically limited in this regard, and it is understood that in some embodiments the sheet resistance for the silver nanowire layer 12 is in the range of 5-100 ops.

In the laminated structure 10 according to the first embodiment, the metal layer 13 is made of a copper material. However, the present disclosure is not so limited. Other suitable materials for forming metal layer 13 include, but are not limited to, molybdenum and aluminum.

The laminated structure 10 of the first embodiment can be non-limitingly produced according to the following steps:
(1) providing a substrate;
(2) coating the substrate with a plurality of silver nanowires;
(3) forming a silver nanowire layer by depositing ITO on a silver nanowire coated substrate by sputtering deposition; and (4) coating a metal layer on said silver nanowire layer.

(Second embodiment)
FIG. 2 is a schematic cross-sectional view of a laminate structure 20 according to a second embodiment of the disclosure. Like the laminated structure 10 in the first embodiment, the laminated structure 20 in the second embodiment also includes a substrate 11, a silver nanowire layer 12 provided on the substrate 11, and an upper portion of the silver nanowire layer 12. and a metal layer 13 provided on the . The silver nanowire layer 12 includes a plurality of silver nanowires and indium tin oxide (ITO) coated on the plurality of silver nanowires.

Compared to the laminated structure 10 in the first embodiment, the laminated structure 20 according to the second embodiment further includes a second silver nanowire layer 22 provided on the underside of the substrate 11 and a second and a second metal layer 23 provided below the silver nanowire layer 22 . The second silver nanowire layer 22 includes a plurality of silver nanowires and indium tin oxide (ITO) coated on the plurality of silver nanowires.

In the laminated structure 20 according to the second embodiment, the ratio of the total thickness of the second silver nanowire layer 22 to the thickness of the ITO, the total thickness of the second silver nanowire layer 22, and the The materials for forming the metal layer 23 are the same as those of the silver nanowire layer 12 and the metal layer 13 in the first embodiment, so they will not be described repeatedly here.

In the laminated structure 20 according to the second embodiment, the second silver nanowire layer 22 and the second metal layer 23 can be made by the same process as described in the first embodiment.

(Third embodiment)
FIG. 3 is an image flow chart showing the process of preparing the touch sensor 30 according to the third embodiment of the present disclosure. As shown in FIG. 3, the touch sensor 30 in the third embodiment includes the laminate structure 10 described in the first embodiment, and the laminate structure 10 is patterned to meet different requirements of the touch sensor 30. there is

As shown in the flowchart of FIG. 3, the process of providing the touch sensor 30 includes (steps of):
1. providing a laminated structure 10 as described in the first embodiment;
2. A photoresist 31 is applied on top of the metal layer 13 and a photolithography process is performed on the photoresist 31; ) 32 and a trace area 33 located outside the laminate structure 10;
3. etching the metal layer 13;
4. removing the remaining photoresist 31;
5. etching the silver nanowire layer 12;
6. applying a second photoresist 34 on top of the metal layer 13;
7. perform the photolithographic process again on the second photoresist 34;
8. 9. again etch metal layer 13; The remaining second photoresist 34 is removed to complete the touch sensor 30 according to the third embodiment of the present disclosure.

(Fourth embodiment)
FIG. 4 is an image flow chart showing the process of preparing the touch sensor 40 according to the fourth embodiment of the present disclosure. As shown, the touch sensor 40 in the fourth embodiment of the present disclosure includes two layers of the laminate structure described in the first embodiment (i.e., laminate structure 10 and another laminate structure 10′), The two laminate structures 10 , 10 ′ are patterned to meet different requirements of the touch sensor 40 .

As shown in the flow chart of FIG. 4, the process for preparing the touch sensor 40 in the fourth embodiment includes (the process of):
1-1 Providing a laminated structure 10 as described in the first embodiment;
1-2 Coating a photoresist 41 on top of the metal layer 13 of the laminate structure 10 and performing a photolithography process on the photoresist 41; defining an active area 42 located and a trace area 43 located outside the laminate structure 10;
1-3 etching the metal layer 13;
1-4 remove the remaining photoresist 41;
1-5 etching the silver nanowire layer 12 of the laminated structure 10;
1-6 Apply a second photoresist 44 on top of the metal layer 13;
1-7 perform the photolithographic process again on the second photoresist 44;
1-8 Etch the metal layer 13 again;
1-9 Remove the remaining second photoresist 44 to complete the driving electrode T _x for the touch sensor 40 according to the fourth embodiment of the present disclosure;
2-1 Providing another laminated structure 10' as described in the first embodiment;
2-2 Applying a third photoresist 45 on top of the metal layer 13' of the laminate structure 10', and performing a photolithography process on the third photoresist 45; the applied third photoresist 45; defines an active area 46 located in the central region of the laminate structure 10' and a trace area 47 located on the outside of the laminate structure 10';
2-3 etching the metal layer 13';
2-4 removing the remaining third photoresist 45;
2-5 etching the silver nanowire layer 12' of the laminated structure 10';
2-6 Applying a fourth photoresist 48 on top of the metal layer 13';
2-7 perform the photolithography process again on the fourth photoresist 48;
2-8 Etch the metal layer 13'again;
2-9 Remove the remaining fourth photoresist 48 to complete the sensing electrode R _x for the touch sensor 40 according to the fourth embodiment of the present disclosure; and 3-1 Step 1- A first coating layer 49 and a second coating layer 49′ are provided on top of the drive electrodes T _x formed in step 9 and the detection electrodes R _x formed in step 2-9, respectively; and a second coating. The drive electrodes T _x covered by the first covering layer 49 are overlaid on the sensing electrodes R _x covered by the layer 49 ′ to complete the touch sensor 40 of the fourth embodiment.

(Fifth embodiment)
FIG. 5 is an image flow chart showing the process of preparing the touch sensor 50 according to the fifth embodiment of the present disclosure. As shown in FIG. 5, the touch sensor 50 in the fifth embodiment includes the laminate structure 20 described in the second embodiment, and the laminate structure 20 is patterned to meet different requirements of the touch sensor 50. there is

As shown in the flow chart of FIG. 5, the process for preparing the touch sensor 50 in the fifth embodiment includes (the process of):
1. providing a laminated structure 20 as described in the second embodiment;
2. A photoresist 51 is applied to the top of the metal layer 13 of the stack 20 and the underside of the second metal layer 23 of the stack 20, and a photolithographic process is performed on the top and bottom photoresist 51, here , the pattern of applied photoresist 51 defines an active area 52 located in the central region of the laminate structure 20 and a trace area 53 located outside the laminate structure 20;
3. etching the metal layer 13 and the second metal layer 23;
4. removing the remaining photoresist 51 from both sides of the laminate structure 20;
5. etching the silver nanowire layer 12 and the second silver nanowire layer 22 of the laminate structure 20;
6. Applying a second photoresist 54 on top of the metal layer 13 and on the underside of the second metal layer 23;
7. Perform the photolithographic process again on the top and bottom second photoresist 54;
8. 8. again etch the metal layer 13 and the second metal layer 23; The remaining second photoresist 54 is removed to complete the touch sensor 50 according to the fifth embodiment of the present disclosure.

(Comparative example 1)
In order to investigate how the ITO contained in the silver nanowire layer of the laminated structure of the present disclosure affects the ESD protection ability of the laminated structure, according to the first embodiment, the ITO in the silver nanowire layer is omitted, A laminated structure is provided that replaces the conventional non-conductive acrylic material. A laminated structure manufactured in this way is used as Comparative Example 1. FIG.

(Test example 1)
In Test Example 1, the laminated structure according to the first embodiment and the laminated structure according to Comparative Example 1 are used to determine which is superior in ESD prevention performance. Both laminate structures have had metal layers removed therefrom and are subjected to electrostatic discharge stresses generated by an ESD simulation device. For laminate structures with better antistatic properties, only relatively little damage (or relatively little change in resistance) is caused by ESD stress. On the other hand, for laminate structures with poor antistatic performance, ESD stress can cause relatively severe damage, increasing the resistance of the laminate structure and breaking silver nanowires.

The test results of Test Example 1 are shown in Table 1 below (unit of measurement: ohms).

As can be seen from the test results in Table 1, the laminated structure according to the first embodiment has clearly superior anti-ESD capability compared to the laminated structure according to Comparative Example 1. This is because ITO is used for the silver nanowire layer instead of the conventional non-conductive resin in the laminated structure of the first embodiment.

(Test example 2)
In Test Example 2, according to the first embodiment, a laminated structure was produced in which the total thickness of the silver nanowire layers was controlled to be 40 nm and the sheet resistance was 50 ops. A laminated structure is used. In Test Example 2, the sample laminate structures used differ from each other only in the ratio of the total thickness of the silver nanowire layer to the thickness of the ITO.

As shown in Table 2, when the total thickness of the silver nanowire layer is the same, the laminated structure with the thickness of ITO greater than or equal to 5 nm can exhibit good anti-ESD ability. The effect of ITO thickness on the visibility of the laminate structure is further investigated. It was found that when the thickness of ITO is in the range of 5-17 nm, the laminated structure can have good anti-ESD ability and good visibility at the same time. It was also found that the visibility of the layered structure is adversely affected when the thickness of the ITO exceeds 17 nm.

Overall, in the laminated structure according to the present disclosure, the total thickness of the silver nanowire layers can range from 40 nm to 120 nm, and the thickness of the ITO can range from 5 nm to 17 nm. Therefore, the ratio of the total thickness of the silver nanowire layers in the laminated structure to the thickness of the ITO is in the range of 40:17 to 120:5. In other words, the total thickness of the silver nanowire layer can be 2.35 to 24 times the thickness of the ITO.

In conclusion, the laminated structure and the touch sensor including the same according to the present disclosure provide at least the following advantageous technical effects:
1. In the laminated structure of the present disclosure, the use of ITO in the silver nanowire layer instead of the conventional non-conductive resin can facilitate the selectivity of the etchant; i.e., in the process of etching the metal layer, The etchant can be used to etch the metal layer without damaging the silver nanowires and ITO, and the process of etching the silver nanowires and ITO also etches the silver nanowires and ITO without etching the metal layer. Other etchants can be used.
2. By combining the network scalability provided by silver nanowires and the continuous conduction provided by ITO, the laminated structure of the present disclosure exhibits reduced contact impedance, good ESD protection without adversely affecting the optical conditions of the laminated structure. , and improved tolerance in reliability analysis.
3. Corresponding to the ITO conductive thin films that are currently mainstream in the market, the laminated structure of the present disclosure can add silver nanowire thin films to the existing ITO optical thin film manufacturing process without undue changes to the manufacturing line and manufacturing process. The technology can be rapidly introduced to combine the advantages of these two types of materials and give the laminated structure even better optical and conductive properties.

Although the present disclosure has been described with particular embodiments, numerous modifications and variations can be made by those skilled in the art without departing from the scope and spirit of the disclosure as set forth in the claims.

Claims (9)

Base material;
a silver nanowire layer provided on top of the substrate; and a metal layer provided on top of the silver nanowire layer;
A laminated structure comprising
The silver nanowire layer is
a plurality of silver nanowires;
Indium tin oxide (ITO) coated on the plurality of silver nanowires; and a total thickness of the silver nanowire layer is 2.35 to 24 times the thickness of the ITO.
A laminated structure characterized by: 2. The laminated structure according to claim 1, wherein the total thickness of said silver nanowire layer is in the range of 40 nm to 120 nm. 3. The laminated structure according to claim 2, wherein the thickness of said ITO in said silver nanowire layer ranges from 5 nm to 17 nm. The laminated structure of any one of claims 1-3, wherein the silver nanowire layer has a sheet resistance in the range of 5-100 ohms/square (ops). moreover,
a second silver nanowire layer provided under the substrate; and a second metal layer provided under the second silver nanowire layer;
including
The second silver nanowire layer is
a plurality of silver nanowires;
ITO coated on the plurality of silver nanowires;
and the total thickness of the second silver nanowire layer is between 2.35 and 24 times the thickness of the ITO of the second silver nanowire layer.
Laminated structure according to any one of claims 1-4. A touch sensor comprising the laminated structure according to any one of claims 1 to 4. 7. The touch sensor of claim 6, wherein the silver nanowire layer and the metal layer of the laminated structure are patterned. The touch sensor comprises two of the laminate structures according to any one of claims 1 to 4, wherein the silver nanowire layers and the metal layers of the two laminate structures are patterned. 8. The touch sensor according to 6 or 7. 6. A touch sensor comprising the laminated structure of claim 5, wherein the silver nanowire layer, the second silver nanowire layer, the metal layer and the second metal layer are patterned.

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