CN111863315A

CN111863315A - Transparent conductive film and touch screen

Info

Publication number: CN111863315A
Application number: CN201910365204.8A
Authority: CN
Inventors: 余飞; 候晓伟
Original assignee: Nanchang OFilm Display Technology Co Ltd
Current assignee: Nanchang OFilm Display Technology Co Ltd
Priority date: 2019-04-30
Filing date: 2019-04-30
Publication date: 2020-10-30

Abstract

The invention provides a transparent conductive film, which comprises a substrate film, wherein the substrate film is sequentially provided with a second hard coating, a base material, a first hard coating and an optical adjusting layer; the transparent conducting layer is formed on the surface, far away from the first hard coating, of the optical adjusting layer; the metal layer is formed on the surface, away from the optical adjusting layer, of the transparent conducting layer; wherein the substrate film has a thermal shrinkage ratio in the longitudinal direction (MD) and the width direction (TD) of 0.1% or less when heated at 150 ℃ for 30 min. Because the thermal shrinkage rate of the substrate film is small, the size of the material cannot be greatly changed due to the high temperature during the formation of the transparent conductive layer, and the problem of wrinkles during the formation of the conductive layer can be effectively solved. In addition, because the dimensional change is small, the alignment precision is high when the device is bonded with other elements, and the device is easy to bond. In addition, the invention also provides a touch screen.

Description

Transparent conductive film and touch screen

Technical Field

The invention relates to a transparent conductive film and a touch panel.

Background

With the development of display technology, current mobile terminals such as mobile phones, smart watches, smart bracelets and the like have a tendency to be light, thin and bendable. Therefore, for a touch screen used in a portable terminal, flexibility, lightness and thinness are also gradually required, a transparent conductive film is a core element of a capacitive touch screen, and in order to meet market demands, plastic films are increasingly used as conductive film substrates.

When a conductive layer such as Indium Tin Oxide (ITO) is formed as a transparent conductive film, or when a metal wiring layer such as copper or silver is formed, the plating temperature is high, and particularly, the temperature is instantaneously raised in the sputtering plating, and further, the subsequent ITO crystallization process is also performed at a high temperature. If the conductive layer is formed by coating the nano-material ink, the curing process is also performed at a high temperature. Therefore, the conductive film is generally kept at a temperature of 120-170 ℃ for several minutes to several hours. However, the glass transition temperature of the plastic film is generally low and is often stretched, and when the plastic film is subjected to the above temperature for a long time and then cooled to room temperature, the film tends to shrink and undergo a large dimensional change. And because the size change is large, the alignment precision is poor when the conductive film is attached to other elements, and the conductive film is easy to deviate.

Disclosure of Invention

The invention provides a transparent conductive film and a touch screen, aiming at solving the problems that the conductive film in the prior art is easy to shrink and has large size change when the transparent conductive layer is formed.

The present invention in a first aspect provides a transparent conductive film comprising:

a substrate film comprising: the substrate comprises a first surface and a second surface which are oppositely arranged; a first hard coat layer formed on the first surface; a second hard coating layer formed on the second surface; the optical adjusting layer is formed on the surface of the first hard coating layer far away from the substrate;

The transparent conducting layer is formed on the surface, far away from the first hard coating, of the optical adjusting layer;

the metal layer is formed on the surface, away from the optical adjusting layer, of the transparent conducting layer;

wherein the substrate film has a thermal shrinkage ratio in the longitudinal direction (MD) and the width direction (TD) of 0.1% or less when heated at 150 ℃ for 30 min.

Because the thermal shrinkage rate of the substrate film is small, the size of the material cannot be greatly changed due to the high temperature during the formation of the transparent conductive layer, and the problem of wrinkles during the formation of the conductive layer can be effectively solved. In addition, because the dimensional change is small, the alignment precision is high when the device is bonded with other elements, and the device is easy to bond.

Preferably, the substrate film has a heat shrinkage rate of 0.05 to 0.07% in the MD direction when heated at 150 ℃ for 30 minutes, and a heat shrinkage rate of 0.03 to 0.04% in the TD direction when heated at 150 ℃ for 30 minutes.

The substrate film has small thermal shrinkage and good dimensional stability, and can prevent wrinkle deformation caused by heating in the subsequent production process.

Preferably, the difference between the heat shrinkage rates of the substrate film in the MD and TD directions when heated at 150 ℃ for 30 minutes is 0.01-0.04%.

The difference of the heat shrinkage rates of the substrate film in two directions is kept in a small range, the film shrinks uniformly as a whole, the size variation difference in the MD and TD directions is small, and the problem of wrinkling is prevented.

Preferably, the substrate film has been heat-treated at a temperature of 150 ℃ and 220 ℃ for a time of 20-600 s.

The substrate film is subjected to a heat treatment before the conductive layer is formed, namely, the substrate film is cooled to room temperature after being subjected to a thermal deformation, and then enters the next high-temperature process. In the heating treatment process, gas and water absorbed by impurities in the substrate film can be separated out, products obtained after hydrolysis of the micromolecule substances can be dehydrated again to form micromolecule substances, the micromolecule substances which are not completely polymerized and the micromolecule substances which are formed after dehydration again, and molecular branched chains and short molecular chains which are broken in the film stretching process can be rearranged on the macromolecular long chains which are freely stretched, so that the atom position and the molecular structure in the base material are adjusted, atoms and molecules in the whole film reach a stable state, the physical stress in various materials and among various materials is eliminated, more stable physical size is obtained, and the influence of temperature change in the subsequent production and processing process on the size of the film is greatly weakened. The heat treatment is carried out at a higher temperature and in a shorter time, so that the substrate film can quickly reach a stable state at the higher temperature, the deformation in the subsequent process is prevented, and the substrate film is prevented from being damaged due to long-time overheating.

Preferably, the heat treatment temperature is higher than a temperature at which the transparent conductive layer is formed.

The heat treatment temperature is higher than the temperature for forming the transparent conductive layer, on one hand, the error of the instrument is balanced, on the other hand, the temperature of the substrate film when the substrate film is subjected to the heat treatment is the same as or higher than the temperature for forming the conductive layer, so once the stable size is reached, the subsequent lower temperature can not generate larger deformation to cause the wrinkle phenomenon.

Preferably, the substrate film subjected to heat treatment is left standing for more than 2 hours to form the transparent conductive layer.

After heat treatment, standing is carried out to enable active molecules in the violent movement rearrangement to gradually stop moving, the interior reaches a new balance to become a stable state, and deformation is not easy to occur during heating in a subsequent process.

Preferably, the material of the substrate is polycycloolefin or polycarbonate.

The two are novel amorphous polymer materials, and compared with the traditional PET, PE and the like, the two are more stable in size at high temperature, smaller and uniform in birefringence, and the formed film is uniform in color. And has higher hardness, excellent light transmission and lower breaking tensile strength.

Preferably, the first hard coating layer contains a plurality of particles, and the surface of the metal layer forms a plurality of protrusions; alternatively, the second hard coat layer contains a plurality of particles, and a plurality of protrusions are formed on the surface of the second hard coat layer.

When the transparent conductive film is rolled into a cylindrical shape, there is a problem that metal layers of adjacent transparent conductive films are stuck to each other and are pressure-bonded. The particles are added into the hard coating to form bulges on the surface of the metal layer, and the bulges can enable the adjacent metal layers to form point contact, thereby avoiding the occurrence of adhesion and compression joint.

Preferably, the distribution density of the protrusions is 100-²。

When the distribution density of the protrusions is too high, the haze value of the transparent conductive film is too high, the light transmittance is reduced, and the appearance and the optical effect of the transparent conductive film are seriously affected. And if the distribution density of the protrusions is too small, the effect of blocking resistance is limited. Within the density range, the transparent conductive film can better give consideration to both the anti-blocking effect and the optical effect.

A second aspect of the present invention provides a touch panel, including two transparent conductive films according to any one of the first aspect, wherein the two transparent conductive films are attached to each other; the touch screen comprises a touch area and a lead area, and the metal layer is located in the lead area; the touch area comprises electrodes formed by etching the transparent conductive layer; the lead area comprises leads formed by etching the metal layer and the transparent conductive layer positioned in the lead area.

In the touch panel, the lead is directly etched from the metal layer and the transparent conductive layer. Therefore, it is not necessary to form a lead wire electrically connected to the electrode by a screen printing method. Compared with the traditional touch screen, the width of the electrode lead wire directly formed by the yellow light process can be further reduced without silk-screen printing, so that the effective touch area is further increased.

Drawings

In order to more clearly illustrate the technical solution in the embodiments of the present invention, the drawings used in the description of the embodiments will be briefly introduced below.

FIG. 1 is a schematic diagram of a stacked structure of a transparent conductive film according to a preferred embodiment of the present invention;

FIG. 2 is a schematic diagram of another stacked structure of a transparent conductive film according to a preferred embodiment of the present invention;

FIG. 3 is a schematic diagram of a stacked structure of another transparent conductive film according to a preferred embodiment of the present invention;

FIG. 4 is a schematic diagram of a stacked structure of a touch panel according to a preferred embodiment of the invention;

FIG. 5 is a schematic diagram of a stacked structure of another touch screen in accordance with a preferred embodiment of the present invention;

10, a transparent conductive film; 101. a substrate film; 11. a substrate; 12. a first hard coat layer; 13. an optical adjustment layer; 14. a transparent conductive layer; 15. a metal layer; 16. a second hard coat layer; 17. particles; 18. a protrusion; 19. an optically clear adhesive; 200. a touch screen; 210. a touch area; 220. a lead region; 211. an electrode; 221. and (7) leading wires.

Detailed Description

In order to make the aforementioned objects, features and advantages of the present invention comprehensible, embodiments accompanied with figures are described in detail below. In the following description, numerous specific details are set forth in order to provide a thorough understanding of the present invention. This invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein.

It will be understood that when an element is referred to as being "secured to" another element, it can be directly on the other element or intervening elements may also be present. When an element is referred to as being "connected" to another element, it can be directly connected to the other element or intervening elements may also be present. The terms "vertical," "horizontal," "left," "right," and the like as used herein are for illustrative purposes only.

Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. The terminology used in the description of the invention herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. As used herein, the term "and/or" includes any and all combinations of one or more of the associated listed items.

Referring to fig. 1 to 3, a transparent conductive film 10 in a preferred embodiment of the invention includes a substrate film 101, a transparent conductive layer 14 and a metal layer 15, wherein the substrate film 101 includes a substrate 11, a first hard coating 12, a second hard coating 16, an optical adjustment layer 13, a first hard coating, a second hard coating, a third hard coating, a fourth hard coating, a fifth hard coating,

the substrate 11 includes a first surface (an upper surface shown in fig. 1) and a second surface (a lower surface shown in fig. 1) that are oppositely disposed. The first surface and the second surface are only used for distinguishing the two surfaces of the substrate 11, and the positions of the first surface and the second surface can be interchanged. The substrate 11 is formed of an amorphous polymer film. Since the amorphous polymer film has a smaller birefringence and is more uniform than the crystalline polymer film, color unevenness in the transparent conductive film 10 of the present invention can be eliminated. The in-plane birefringence of the amorphous polymer film used in the present invention is preferably 0 to 0.001, and more preferably 0 to 0.0005. The variation in-plane birefringence of the amorphous polymer film used in the present invention is preferably 0.0005 or less, and more preferably 0.0003 or less.

The birefringence and the variation thereof can be achieved by selecting an appropriate type of amorphous polymer film. Specifically, in the present embodiment, the substrate 11 is polycycloolefin or polycarbonate. The thickness of the substrate 11 formed of the amorphous polymer thin film is 20 μm to 200 μm. The reason for this is that when the thickness of the substrate is set to a value within the above range, the coatability of the hard coat layer and the subsequent lamination property of the transparent conductive film can be made excellent, and the generation of outgas due to the transparent plastic film substrate can be suppressed.

The first hard coat layer 12, the optical adjustment layer 13, the transparent conductive layer 14, and the metal layer 15 are sequentially formed on the first surface of the base material 11. The second hard coat layer 16 is formed on the second surface of the substrate 11. Wherein:

the first hard coat layer 12 protects the first surface of the substrate 11. The first hard coat layer 12 contains a binder resin. The binder resin includes, for example, a curable resin composition based on ultraviolet rays or electron beams. The curable resin composition preferably contains a polymer obtained by addition reaction of a glycidyl acrylate polymer and acrylic acid. Alternatively, the curable resin composition preferably contains a multifunctional acrylate polymer (pentaerythritol, dipentaerythritol, etc.). The curable resin composition further contains a polymerization initiator. The second hard coat layer 15 has the same function and material composition as the first hard coat layer 12, and thus, will not be described herein.

The first hard coat layer 12 and the second hard coat layer 16 have a thickness of 0.5 to 5 μm and the same thickness. When the thicknesses of the two hard coatings are within the above ranges, the laminated structure has good scratch resistance.

The optical adjustment layer 13 is used to improve the optical effect of the transparent conductive film 11. Specifically, after patterning the transparent conductive layer 14 in the subsequent step, the difference in reflectance between the portion having the transparent conductive layer 14 and the portion not having the transparent conductive layer is reduced, and the pattern of the transparent conductive layer 14 is difficult to recognize. The material forming the optical adjustment layer 13 is, for example, a urethane polymer. The thickness of the optical adjustment layer 13 is preferably 50nm to 500 nm. If the optical adjustment layer 13 is too thin, the matching refractive index cannot be adjusted, and the laminated structure cannot achieve high transmittance; if the optical adjustment layer 13 is too thick, the transmittance is low and the haze is high. When the thickness of the optical adjustment layer 13 is within the above range, the above requirements can be satisfied. The refractive index of the optical adjustment layer 13 is preferably set to a value between the refractive index of the first hard coat layer 12 and the refractive index of the transparent conductive layer 14. Therefore, the transition effect can be realized on the propagation path of the light.

The transparent conductive layer 14 is formed on the surface of the optical adjustment layer 13. The transparent conductive layer 14 has a transmittance in the visible light region (380nm-780nm) of 80% or more and a surface resistance value per unit area (unit: Ω/m)²) Is 500 omega/m²The following layers are formed. The thickness of the transparent conductive layer 14 is preferably 15nm to 100nm, more preferably 15nm to 80nm, and still more preferably 20nm to 50 nm. The transparent conductive layer 14 is formed of, for example, any one of Indium Tin Oxide (ITO), indium zinc oxide, or an indium oxide-zinc oxide composite. Or may be formed of any one or two or more of nanomaterials such as metal nanowires, graphene, or carbon nanotubes.

The metal layer 15 is formed on the surface of the transparent conductive layer 14. The metal layer 15 is used to form a wiring outside the touch input region when the transparent conductive film of the present invention is used for a touch panel, for example. The material for forming the metal layer 15 is typically copper, silver, or a copper-nickel alloy, and any metal having excellent conductivity other than copper may be used. The thickness of the metal layer 15 is preferably 20nm to 500nm, more preferably 100nm to 300 nm.

In the present example, the thermal shrinkage rates in the longitudinal direction (MD) and the width direction (TD) of the substrate film 101 when heated at 150 ℃ for 30min were 0.1% or less.

In the present embodiment, the heating shrinkage rate in the longitudinal direction (MD direction) and the heating shrinkage rate in the width direction (TD direction) of the substrate film 101 are calculated in the following manner. Specifically, the substrate film 101 was cut into a size (test piece) of 100mm in width and 100mm in length, a cross mark was drawn on the test piece side along a line of 80mm in length in each of the MD direction and the TD direction, and the lengths (mm) of the marks in the MD direction and the TD direction were measured by an olympus digital mini-measuring microscope STM5 (manufactured by olympus optical industries). Then, the test piece was subjected to heat treatment (150 ℃ C., 30 min). The resulting mixture was allowed to stand and cool at room temperature for 1 hour, and the lengths of the marks in the MD and TD were measured again, and the measured values were substituted into the following formulas to determine the respective heating shrinkage ratios in the MD and TD.

The heat shrinkage ratio (%) × 100 [ [ length of mark before heating (mm) -length of mark after heating (mm) ]/length of mark before heating (mm) ].

Since the thermal shrinkage of the base film 101 is small, the material size does not change significantly at high temperature when the transparent conductive layer 14 is formed, and the problem of wrinkles occurring when the transparent conductive layer 14 is formed can be effectively suppressed. In addition, because the dimensional change is small, the alignment precision is high when the device is bonded with other elements, and the device is easy to bond.

Further, in this embodiment, the substrate film 101 has a thermal shrinkage rate in the MD direction of 0.05 to 0.07% when heated at 150 ℃ for 30min, and the substrate film 101 has a thermal shrinkage rate in the TD direction of 0.03 to 0.04% when heated at 150 ℃ for 30 min.

In this embodiment, the difference between the heat shrinkage rates in the MD and TD directions of the substrate film 101 when heated at 150 ℃ for 30min is 0.01 to 0.04%.

The difference in the heat shrinkage rates in both directions of the substrate film 101 is maintained within a small range, the film shrinks uniformly as a whole, and the difference in the dimension changes in the MD and TD directions is small, preventing the problem of wrinkles.

In the present embodiment, the substrate film 101 has been subjected to heat treatment, and the transparent conductive layer 14 is formed on the surface of the substrate film 101 subjected to heat treatment. The heat treatment temperature of the substrate film 101 is 150-220 ℃, preferably 170-200 ℃, and more preferably 180-190 ℃. The heat treatment time of the substrate film 101 is 20 to 600s, preferably 30 to 200s, and more preferably 60 to 120 s.

Before the conductive layer 14 is formed, the substrate film 101 is subjected to a heat treatment, i.e., a thermal deformation, cooled to room temperature, and then subjected to the next high-temperature process. In the heating treatment process, gas and water absorbed by impurities in the substrate film 101 can be separated out, products obtained after hydrolysis of the small molecular substances can be dehydrated again to form the small molecular substances, the small molecular substances which are not completely polymerized and the small molecular substances which are formed after dehydration again, and molecular branched chains and short molecular chains which are broken in the film stretching process can be rearranged on the macromolecular long chains which are freely stretched, so that the atom position and the molecular structure in the substrate are adjusted, atoms and molecules in the whole film reach a stable state, the physical stress in various materials and among various materials is eliminated, more stable physical dimensions are obtained, and the influence of temperature change in the subsequent production and processing process on the dimensions of the film is greatly weakened. The heat treatment is carried out at a higher temperature for a shorter time, so that the substrate film 101 quickly reaches a stable state at the higher temperature, the deformation in the subsequent process is prevented, and meanwhile, the substrate film 101 is prevented from being damaged due to long-time overheating.

In this embodiment, the heat treatment temperature of the substrate film 101 is higher than the temperature at the time of forming the transparent conductive layer 14. It is preferable that the difference between the heat treatment temperature and the temperature at which the transparent conductive layer is formed is greater than 10 ℃. The heat treatment temperature is higher than the temperature for forming the transparent conductive layer, on one hand, the error of the instrument is balanced, on the other hand, the temperature of the substrate film when the substrate film is subjected to the heat treatment is the same as or higher than the temperature for forming the conductive layer, so once the stable size is reached, the subsequent lower temperature can not generate larger deformation to cause the wrinkle phenomenon.

In this embodiment, the substrate film 101 subjected to the heat treatment is left to stand for 2 hours or more to form the transparent conductive layer 14. Preferably 2 to 48 hours, more preferably 8 to 24 hours. After heat treatment, standing is carried out to enable active molecules in the violent movement rearrangement to gradually stop moving, the interior reaches a new balance to become a stable state, and deformation is not easy to occur during heating in a subsequent process.

Further, the first hard coat layer 12 and/or the second hard coat layer 16 contain a plurality of particles 17 to form a plurality of protrusions 18 on the surface of the conductive film. Specifically, the particles 17 may be randomly or may be distributed in the first hard coat layer 12 and/or the second hard coat layer 16 in a predetermined regular (e.g., uniform) distribution. The particles 17 may be spherical, ellipsoidal, or other suitable shapes, and may be amorphous particles. In this embodiment, the particles 17 are spherical.

With continued reference to fig. 1 to 3, the particles 17 may be contained in only the first hard coat layer 12 or the second hard coat layer 16, or may be contained in both the first hard coat layer 12 and the second hard coat layer 16, thereby obtaining the transparent conductive film 10 with the protrusions 18 formed on both sides. When the first hard coat layer 12 contains the particles 17, a plurality of protrusions 18 are formed on the surface of the metal layer 15.

The first hard coat layer 12 is taken as an example for explanation:

the particles 17 protrude from the surface of the first hard coat layer 12, so that the surface of the first hard coat layer 12 forms a convex region, and the region of the first hard coat layer 12 not provided with the particles 17 forms a flat region. Since the optical adjustment layer 13, the transparent conductive layer 14, and the metal layer 15 are sequentially stacked on the surface of the first hard coat layer 12, the surface shapes of the three layers are the same as the surface shape of the first hard coat layer 12. Therefore, a plurality of projections 18 are formed in the region of the metal layer 13 corresponding to the particles 17.

Similarly, when the particles 17 are contained in the second hard coat layer 16, the surface thereof also forms convex regions.

When the transparent conductive film 10 is manufactured in a roll-to-roll process, the particles 17 form a plurality of protrusions 18 on the surface of the metal layer 15. Therefore, when the transparent conductive film 10 is curled, the plurality of protrusions 16 can make point contact between two adjacent metal layers, thereby preventing adhesion and pressure contact between the metal layers.

The size of the particles 17 in the direction perpendicular to the surface of the substrate 11 may be larger than the thickness of the flat region; or less than or equal to the thickness of the flat region, in which case there is a gap between the particles 17 and the surface of the substrate 11 to form a convex region (not shown) on the surface. That is, it is equivalent to suspending the particles 17 in the first hard coat layer 12 and/or the second hard coat layer 16, and thus, the particles 17 do not come into direct contact with the surface of the substrate 11. Therefore, even if the surface of the particle 17 has an irregular protruding structure, the base material 11 is not damaged.

In the present embodiment, the first hard coat layer 12 and the second hard coat layer 16 each contain particles 17, so that a plurality of convex regions are formed on both sides of the transparent conductive film 10. Therefore, when the transparent conductive film 10 is rolled, the number of points of point contact between two adjacent metal layers increases, and therefore the anti-blocking and anti-pressure contact effects are more excellent.

The material of the particles 17 is silica, zirconia, a silicone polymer, an acrylic polymer, or a styrene polymer, or a composite of the above materials, and may be other suitable materials. In the present embodiment, the particles 17 are made of the same material as the first hard coat layer 12 and the second hard coat layer 16.

Since the material of the particles 17 is the same as that of the first hard coat layer 12 and the second hard coat layer 16, the optical parameters are also the same. Therefore, at the interface of the particle 17 and the hard coat layer, light transmission is less affected, and the particle 17 and the hard coat layer are more closely integrated. When light passes through the first hard coat layer 12 and the second hard coat layer 16 containing the particles 17, the distortion of the propagation path thereof is small. Therefore, the transparent conductive film 10 can prevent the optical properties from being adversely affected while achieving the purpose of blocking resistance and bonding resistance.

In order to achieve better anti-blocking and anti-bonding effects, there are corresponding requirements for the surface roughness of the transparent conductive film 10 and the density of the protrusions 18.

In the present embodiment, the distribution density of the protrusions 18 is 100-3000/mm 2.

When the distribution density of the protrusions 18 is too high, the haze value of the transparent conductive film 10 is too high, and the light transmittance is lowered, thereby seriously affecting the appearance and the optical effect of the transparent conductive film 10. Whereas if the distribution density of the protrusions 18 is too small, the effect of blocking resistance is limited. Within the above density range, the transparent conductive film 10 can preferably achieve both the anti-blocking and optical effects.

Wherein the distribution density of the protrusions 18 can be changed by adjusting the shape, size and content of the particles 17.

Further, in the present embodiment, the height of the plurality of projections 18 in the direction perpendicular to the surface of the metal layer 15 is 0.1 to 0.5 μm.

The height of the bump 18 refers to the height of the bump 18 protruding from the surface of the metal layer 15. Because of the small size of the particles 17, it is difficult to precisely control the height of each protrusion 18. Therefore, the height of the projection 18 may be controlled within the above height range. It should be noted that, in actual production, since it is difficult to accurately control each particle 17, it is difficult to avoid that the height of the projection 18 formed by a very small portion of the particle 17 is outside the above range. However, the effect of the portion of the projection 18 is negligible. And the height of the projections 18 may also refer to an arithmetic average of the heights of a number of projections 18 within a predetermined range.

In general, the higher the height of the projections 18, the better the anti-blocking effect. However, as the height increases, the size of the particles 17 needs to be increased, so that the haze value of the transparent conductive film 10 is increased, and the optical effect of the transparent conductive film 10 is seriously affected to a certain extent. Within the above height range, the transparent conductive film 10 can achieve both the anti-blocking effect and the optical effect.

In addition, the invention also provides a touch screen. Referring to fig. 4 and 5, a touch panel 200 according to a preferred embodiment of the present invention is made of the transparent conductive film 10 of the above-mentioned embodiment. Wherein:

touch screen 200 includes a touch region 210 and a lead region 220. Specifically, the touch region 210 is located in the middle of the touch screen 200, and the lead line regions 220 are disposed around the circumference of the touch region 210. Metal layer 15 is located at lead pad 220. The transparent conductive layer 14 in the touch area 210 is etched to form an electrode 211. The plurality of electrodes 211 form an electrode pattern. The metal layer 15 in the lead region 220 and the transparent conductive layer 14 in the lead region 220 are etched to form the lead 221, i.e. the lead 221 has a double-layer structure. Then, the two etched transparent conductive films 10 are bonded to each other with an optically transparent adhesive 19 to form the touch panel 200. The electrodes of the two transparent conductive films 10 are spatially crossed with each other to form a driving electrode and a sensing electrode of a capacitive structure.

In this embodiment, the second hard coat layers 16 of the two etched transparent conductive films 10 are bonded to each other to form the touch panel 200. In other embodiments, touch screen 200 may also be formed by second hard coat layer 16 attached to touch pad 210 and lead pad 220.

In the touch screen, the metal layer 15 and the transparent conductive layer 14 are directly etched to obtain the lead 221, and the width of the electrode lead directly formed by the yellow light process can be further reduced without silk printing, so that the effective touch space of the touch screen is further increased.

The technical features of the embodiments described above may be arbitrarily combined, and for the sake of brevity, all possible combinations of the technical features in the embodiments described above are not described, but should be considered as being within the scope of the present specification as long as there is no contradiction between the combinations of the technical features.

The above description is only for the purpose of illustrating the preferred embodiments of the present invention and is not to be construed as limiting the invention, and any modifications, equivalents and improvements made within the spirit and principle of the present invention are intended to be included within the scope of the present invention. Therefore, the protection scope of the present patent shall be subject to the appended claims.

Claims

1. A transparent conductive film comprising:

a substrate film comprising: the substrate comprises a first surface and a second surface which are oppositely arranged; a first hard coat layer formed on the first surface; a second hard coating layer formed on the second surface; and an optical adjusting layer formed on the surface of the first hard coating layer far away from the substrate;

the transparent conducting layer is formed on the surface, far away from the first hard coating, of the optical adjusting layer; and

Characterized in that the substrate film has a thermal shrinkage of less than 0.1% in the longitudinal direction (MD) and the width direction (TD) when heated at 150 ℃ for 30 minutes.

2. The transparent conductive film according to claim 1, wherein the substrate film has a thermal shrinkage rate in the MD direction of 0.05 to 0.07% when heated at 150 ℃ for 30 minutes, and the substrate film has a thermal shrinkage rate in the TD direction of 0.03 to 0.04% when heated at 150 ℃ for 30 minutes.

3. The transparent conductive film according to claim 1, wherein the difference between the thermal shrinkage rates in the MD and TD directions of the substrate film when heated at 150 ℃ for 30 minutes is 0.01-0.04%.

4. The transparent conductive film of claim 1, wherein the substrate film has been heat treated at a temperature of 150 ℃ and 220 ℃ for a period of 20-600 s.

5. The transparent conductive film according to claim 2, wherein the heat treatment temperature is higher than a temperature at which the transparent conductive layer is formed.

6. The transparent conductive film according to claim 2, wherein the substrate film is left standing for 2 hours or more to form the transparent conductive layer.

7. The transparent conductive film according to claim 1, wherein the substrate is polycycloolefin or polycarbonate.

8. The transparent conductive film according to claim 1, wherein the first hard coat layer contains a plurality of particles, and a plurality of protrusions are formed on the surface of the metal layer; alternatively, the second hard coat layer contains a plurality of particles, and a plurality of protrusions are formed on the surface of the second hard coat layer.

9. The transparent conductive film as claimed in claim 8, wherein the distribution density of the protrusions is 100-3000 protrusions/mm²。

10. A touch panel comprising two transparent conductive films according to any one of claims 1 to 9, wherein the two transparent conductive films are adhered to each other; the touch screen is provided with a touch area and a lead area, and the metal layer is located in the lead area; the touch area comprises electrodes formed by etching the transparent conductive layer; the lead area comprises leads formed by etching the metal layer and the transparent conductive layer positioned in the lead area.