JP2021099418A - Optical film - Google Patents

Abstract

To provide an optical film that is excellent in visible light transmission property and heat ray reflection property and has reduced redness.SOLUTION: An optical film 10 comprises: a transparent resin film 2; a first layer 11 that has a refractive index of 1.95 or more and 2.08 or less in light with a wavelength of 550 nm and is formed of oxide; a second layer 12 that is formed of silver or a silver alloy; a third layer 13 that is formed of oxide; a fourth layer 14 that is formed of silver or the silver alloy; and a fifth layer 15 that is formed of oxide. The thickness of the first layer 11 (t1), the thickness of the second layer (t2), the thickness of the third layer 13 (t3), the thickness of the fourth layer 14 (t4), and the thickness of the fifth layer 15 (t5) satisfy the conditions (A) to (F) shown below. (A) t2≥6.0(nm); (B) t2≤t4; (C) (t2+t4)≤25.0(nm); (D) 2.15≤t1/t2≤3.00; (E) t1≤t5<t3; (F) (t1+t3+t5)≤150.0(nm).SELECTED DRAWING: Figure 1

Description

The present invention relates to an optical film.

An optical film that reflects heat rays (infrared rays) while transmitting visible light is known (for example, Patent Document 1). This type of optical film is attached to, for example, the window glass of a building, an automobile, or the like, and is used to reflect sunlight (infrared rays) to prevent the temperature inside the room from rising.

Such optical films include, for example, as shown in Patent Document 1, a reflective layer made of a metal thin film for reflecting heat rays and a metal oxide thin film for enhancing visible light transmission on a resin film. It is known that the optical adjustment layers made of the above are alternately laminated.

It should be noted that an optical laminate having a structure in which layers mainly composed of silver (heat shield layer) and layers mainly composed of ZnO are alternately laminated on a glass plate instead of a resin film transmits visible light. It is known to have properties and heat insulating properties (heat ray reflecting property) (for example, Patent Document 2). This optical laminate is said to exhibit a slightly greenish color tone when viewed from the glass plate side.

Japanese Unexamined Patent Publication No. 2015-180528 Japanese Unexamined Patent Publication No. 11-34216

Since the optical film shown in Patent Document 1 has heat ray reflectivity, it easily reflects even light in the visible light region (that is, red light) close to the wavelength of the heat ray (infrared ray). Therefore, although this type of optical film is transparent, it sometimes looks like a reddish tint.

Further, as shown in Patent Document 2, in the case of an optical laminate in which a heat shield layer or the like is formed on a glass plate, the glass plate is post-processed to have various object shapes (for example, curved surfaces). It is difficult to freely mold it to fit the windshield and window film of automobiles. Therefore, as this kind of optical laminate, one in which a heat shield layer or the like is formed on a flexible resin film is required.

However, although the optical laminate using a glass plate as a base material can easily adjust the color tone and heat ray reflectivity, the optical film using a resin film as a base material can easily adjust the color tone and heat ray reflectivity. Etc. are difficult to adjust to a desired value. This is because the heat resistance of the resin film in the optical film manufacturing process (heating process) and the influence of outgas generated from the resin film are larger than expected. Due to such circumstances, it is difficult to provide an optical film using a resin film having the same performance (visible light transmittance, heat ray reflectivity, color tone, etc.) as an optical laminate using a glass plate, which is a problem. It was.

An object of the present invention is to provide an optical film having excellent visible light transmittance and heat ray reflectivity and reduced redness.

The means for solving the above-mentioned problems are as follows. That is,
<1> On a first layer composed of a transparent resin film, an oxide arranged on the resin film and having a refractive index of 1.95 or more and 2.08 or less in light having a wavelength of 550 nm, and the first layer. Arranged, a second layer made of silver or a silver alloy, arranged on the second layer, arranged on a third layer made of the oxide, and arranged on the third layer, made of the silver or the silver alloy. An optical film comprising a fourth layer and a fifth layer made of the oxide arranged on the fourth layer, wherein the thickness of the first layer (t1) and the thickness of the second layer (t2). , The thickness of the third layer (t3), the thickness of the fourth layer (t4), and the thickness of the fifth layer (t5) satisfy the conditions (A) to (F) shown below. Optical film.
(A) t2 ≧ 6.0 (nm)
(B) t2 ≤ t4
(C) (t2 + t4) ≤25.0 (nm)
(D) 2.15 ≦ t1 / t2 ≦ 3.00
(E) t1 ≦ t5 <t3
(F) (t1 + t3 + t5) ≤150.0 (nm)

<2> The optical film according to claim 1, wherein the oxide is IZO.

<3> The optical film according to <1> or <2>, which is interposed between the resin film and the first layer and includes a base layer made of silicon oxide.

<4> The optical film according to any one of <1> to <3>, wherein the total light transmittance is 70% or more.

<5> The optical film according to any one of <1> to <4>, wherein the visible light reflectance is 10% or less.

<6> The optical film according to any one of <1> to <5>, wherein the heat ray shielding rate is 50% or more and the reflected chromaticity (a ^{*) is 5.0 or less.}

<7> A base material with an optical film comprising the optical film according to any one of <1> to <6> and a transparent base material on which the optical film is laminated to support the optical film.

According to the present invention, it is possible to provide an optical film having excellent visible light transmittance and heat ray reflectivity and reduced redness.

A cross-sectional view schematically showing the configuration of the optical film according to the embodiment. Sectional drawing schematically showing the structure of the optical film which concerns on another embodiment Sectional drawing schematically showing the structure of the base material with an optical film

[Optical film]
An optical film according to an embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a cross-sectional view schematically showing the configuration of the optical film 10 according to the embodiment. As shown in FIG. 1, the optical film 10 includes a resin film 2, a first layer 11, a second layer 12, a third layer 13, a fourth layer 14, and a fifth layer 15. The first layer 11 to the fifth layer 15 are laminated on the resin film 2 in this order.

In the present specification, the first layer 11, the third layer 13, and the fifth layer 15 are each composed of an "optical adjustment layer", and the second layer 12 and the fourth layer 14 are each composed of a "heat ray reflecting layer". Become.

(Resin film)
The resin film 2 is a transparent resin film that supports a laminate such as the first layer 11. The resin film has a visible light transmittance of 90% or more while having appropriate flexibility. The resin material constituting the resin film 2 is not particularly limited as long as the object of the present invention is not impaired, and examples thereof include a polyester resin having excellent transparency. As the polyester resin, for example, polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polyethylene naphthalate and the like can be used. Further, as long as transparency is ensured, a resin material other than polyester resin may be used, for example, a polyolefin resin such as polyethylene and polypropylene, a polyamide resin such as nylon 6 and nylon 12, a polyvinyl alcohol, and an ethylene-vinyl alcohol copolymer. Vinyl alcohol resins such as, polystyrene, triacetyl cellulose, acrylic, polyvinyl chloride, polycarbonate, polyimide, polyether sulfone, cyclic polyolefins and other resin materials may be used.

The resin film 2 may be a single layer, or may have a structure in which a flattening layer (hard coat layer) is formed on both sides or one side of a core material made of a resin film. The flattening layer is made of, for example, an ultraviolet curable acrylic resin composition.

The thickness of the resin film 2 is not particularly limited as long as the object of the present invention is not impaired, but is preferably 3 μm to 200 μm, for example.

It is desirable that the resin film 2 has heat resistance. The specific heat resistant temperature of the resin film 2 is, for example, preferably 60 ° C. or higher, more preferably 100 ° C. or higher, and even more preferably 200 ° C. or higher. Further, as the resin film 2, it is preferable that the resin film 2 generates less outgas (for example, water content and low molecular weight monomer) in the process of forming the optical adjustment layer and the heat ray reflection layer, which will be described later. In order to remove water, low molecular weight monomers, etc. contained in the resin film 2 in advance, as a pretreatment of the resin film 2, for example, a treatment of heating and drying the resin film 2 at 60 ° C. to 90 ° C. in a vacuum. May be done.

Further, as long as the object of the present invention is not impaired, the surface of the resin film 2 may be subjected to surface treatment such as plasma treatment (vacuum plasma treatment, atmospheric pressure plasma treatment), corona discharge treatment, flame treatment, etc., if necessary. Good.

(Heat ray reflective layer)
The heat ray reflecting layer is made of silver or a thin film of silver alloy containing silver as a main component, and has a function of mainly reflecting heat rays (infrared rays). Examples of the silver alloy constituting the heat ray reflecting layer or a silver alloy containing silver as a main component include silver such as silver (Ag), silver-palladium alloy (AgPd), silver-palladium-copper alloy (AgPdCu), and silver-copper alloy (AgCu). Alloys can be mentioned. The proportion of silver contained in the silver alloy as a main component is 95 atomic% or more, preferably 98 atomic% or more. As the silver or silver alloy used for the heat ray reflecting layer, a silver-palladium alloy is preferable.

The thickness (t2) of the second layer 12 which is the heat ray reflecting layer is 6.0 nm or more.

Further, the thickness (t2) of the second layer 12 is equal to or less than the thickness (t4) of the fourth layer 14 which is a heat ray reflecting layer.

The total of the thickness (t2) of the second layer 12 and the thickness (t4) of the fourth layer 14 is 25.0 nm or less.

In the case of the present embodiment, the second layer 12 and the fourth layer 14 are made of the same material. In other embodiments, silver or a silver alloy containing silver as a main component may be used as long as the object of the present invention is not impaired.

(Optical adjustment layer)
The optical adjustment layer is a layer made of a thin film of oxide having a refractive index of 1.95 or more and 2.08 or less in light having a wavelength of 550 nm, and is visible light in the heat ray reflecting layer (second layer 12, fourth layer 14). It is formed for the purpose of improving the transparency of visible light while suppressing the reflection of light. The first layer 11 which is an optical adjustment layer is formed on the resin film 2. The first layer 11 of this embodiment is formed directly on the resin film 2. The second layer 12 is laminated on such a first layer 11.

The third layer 13, which is an optical adjustment layer, is formed on the second layer 12. The first layer 11 and the third layer 13 are formed so as to sandwich the second layer 12. The fourth layer 14 is laminated on the third layer 14.

The fifth layer 15, which is an optical adjustment layer, is formed on the fourth layer 14. The third layer 13 and the fifth layer 15 are formed so as to sandwich the fourth layer 14.

The optical adjustment layer is composed of an oxide having a refractive index of 1.95 or more and 2.08 or less in light having a wavelength of 550 nm. Examples of such an oxide include IZO, which is a composite oxide of _{indium oxide (In 2} O _{3) and zinc oxide (Zn O).} The refractive index of a general IZO in light having a wavelength of 550 nm is 2.00 or more and 2.05 or less.

The thickness (t1) of the first layer 11 is not particularly limited as long as the object of the present invention is not impaired, but is preferably 15.0 nm or more, more preferably 16.0 nm or more, preferably 37.0 nm or less, and 36. More preferably 0.0 nm or less.

The thickness (t1) (that is, t1 / t2) of the first layer 11 with respect to the thickness (t2) of the second layer 12 is 2.15 ≦ t1 / t2 ≦ 3.00. It should be noted that t1 / t2 is preferably 2.20 or more, and preferably 2.95 or less.

The thickness (t3) of the third layer 13 is not particularly limited as long as the object of the present invention is not impaired, but for example, 50.0 nm or more is preferable, 52.0 nm or more is more preferable, and 54.0 nm or more is particularly preferable. 75.0 nm or less is preferable, 73.0 nm or less is more preferable, and 70.0 nm or less is particularly preferable.

The thickness (t5) of the fifth layer 15 is not particularly limited as long as the object of the present invention is not impaired. For example, for example, 19.0 nm or more is preferable, 20.0 nm or more is more preferable, and 38.0 nm or less is preferable. , 37.0 nm or less is more preferable.

The thickness (t5) of the fifth layer 15 is equal to or greater than the thickness (t1) of the first layer 11 (that is, t1 ≦ t5). Further, the thickness (t3) of the third layer 13 is larger than the thickness (t5) of the fifth layer 15 (t5 <t3). Therefore, there is a relationship of t1 ≦ t5 <t3 between these thicknesses.

The total of the thickness of the first layer 11 (t1), the thickness of the third layer 13 (t3), and the thickness of the fifth layer 15 (t5) is 150.0 nm or less.

(Relationship between layers)
Between the thicknesses (t1 to t5) of the first layer 11, the second layer 12, the third layer 13, the fourth layer 14, and the fifth layer 15 described above, the relational expressions (A) to (F) shown below are shown below. ) Holds.
(A) t2 ≧ 6.0 (nm)
(B) t2 ≤ t4
(C) (t2 + t4) ≤25.0 (nm)
(D) 2.15 ≦ t1 / t2 ≦ 3.00
(E) t1 ≦ t5 <t3
(F) (t1 + t3 + t5) ≤150.0 (nm)

When the above relational expressions (A) to (F) are established between the first layer 11 and the like, the visible light transmittance and the heat ray reflectivity are excellent, and the redness is reduced.

In the case of the present embodiment, the first layer 11, the third layer 13, and the fifth layer 15 are made of the same material. In other embodiments, oxides of different materials (oxides having a refractive index of 1.95 or more and 2.08 or less in light having a wavelength of 550 nm) may be used as long as the object of the present invention is not impaired. ..

(Film formation method)
The method of forming the heat ray reflecting layer (second layer 12, fourth layer 14) and the optical adjustment layer (first layer 11, third layer 13, fifth layer 15) on the resin film 2 is particularly limited. However, it is appropriately selected according to the purpose. Examples of the film forming method include physical vapor deposition such as vacuum vapor deposition (electron beam vapor deposition, resistance heating vapor deposition), sputtering, ion plating, ion beam, ion assist, and laser ablation. Examples thereof include chemical vapor deposition (CVD) methods such as PVD) method, thermal CVD method, optical CVD method, and plasma CVD method. Among these, the physical vapor deposition (PVD) method is preferable, and the sputtering method is particularly preferable because it is easy to reliably laminate the first layer 11 on the resin film 2.

Further, as the sputtering method, a DC sputtering method having a high film forming rate is preferable. In the case of multi-layer film formation by the sputtering method, a one-chamber method may be used in which a plurality of targets are alternately or sequentially formed in one chamber, or a multi-chamber method in which a plurality of chambers are continuously formed. However, the multi-chamber method is preferable from the viewpoint of productivity and prevention of material contamination.

As the film forming temperature condition at the time of film formation using a sputtering method or the like, a low temperature condition (for example, -20 ° C. to 60 ° C. temperature range) is preferred.

(Underground layer)
FIG. 2 is a cross-sectional view schematically showing the configuration of the optical film 10A according to another embodiment. In the optical film 10A of the present embodiment, the first layer 11 is formed on the resin film 2 via the base layer 3. This is the same as that of the first embodiment except that the base layer 3 is interposed between the resin film 2 and the first layer 11. The base layer 3 may be used for the purpose of improving the adhesion of the first layer 11 to the resin film 2 and the processability of the optical film 10A. The base layer 3 is not particularly limited as long as it does not affect the optical characteristics (visible light transmission, heat ray reflectivity, redness reduction, etc.) of the optical film 10A. For example, as the base layer, A thin film of silicon oxide (SiOx) made of SiO _{2 or the like may be used.} The thickness of the base layer is preferably 3.0 nm or more and 10.0 nm or less, for example. The base layer is formed by a sputtering method or the like, like the first layer 11 or the like.

(Other layers)
Other layers such as a protective layer (barrier layer) may be formed on the optical films 10 and 10A.

(Total light transmittance)
The optical films 10 and 10A have a total light transmittance of 70% or more and are excellent in visible light transmittance. The method for measuring the total light transmittance will be described later.

(Visible light reflectance)
The optical films 10 and 10A have a visible light reflectance of 10% or less. The method for measuring the visible light reflectance will be described later.

(Heat ray shielding rate)
The optical films 10 and 10A have a heat ray shielding rate of 50% or more and are excellent in heat ray reflectivity. The method for measuring the heat ray shielding rate will be described later.

(Reflective chromaticity)
The optical films 10 and 10A have a reflection chromaticity (cci) (a ^* ) of 5.0 or less, and the redness is suppressed. The method for measuring the reflected chromaticity will be described later.

(Use)
Since the optical films 10 and 10A have excellent visible light transmission and suppress redness, even if they are attached to a window glass or the like of a building, they do not stand out to the user and do not give a sense of discomfort. Such optical films 10 and 10A are attached to various windowpanes and transparent members such as windowpanes of buildings, vehicles (for example, automobiles, trains), and windowpanes of vehicles such as ships, and are used for heat insulation and heat insulation. Can be used for.

When the optical films 10 and 10A are attached to the window glass of the building from the indoor side, for example, in winter, the heat in the room (heated room) is suppressed from being transferred to the outside through the window glass. The glass.

Here, an example of using the optical film 10 will be described with reference to FIG. FIG. 3 is a cross-sectional view schematically showing the configuration of the base material 100 with an optical film. The base material 100 with an optical film has a structure in which the optical film 10 is sandwiched between a pair of transparent glass base materials 50, 50. Transparent adhesive layers 40, 40 are formed on both sides of the optical film 10, and are attached to the glass substrates 50, 50 by utilizing them. Such a base material 10 with an optical film is used, for example, as a window glass of an automobile or a building.

Hereinafter, the present invention will be described in more detail based on Examples. The present invention is not limited to these examples.

In the examples and comparative examples shown below, each layer was formed on the resin film by using a roll-to-roll magnetron sputtering apparatus. Further, the flow rate of the gas supplied into each chamber of the sputtering apparatus was appropriately adjusted by using a predetermined mass flow controller.

[Example 1]
As a resin film, a PET film (thickness: 50 μm) was prepared. On one side of the PET, a first layer made of an IZO film, a second layer made of a silver-palladium alloy (AgPd) film, a third layer made of an IZO film, and a third layer made of a silver-palladium alloy (AgPd) film. The fourth layer and the fifth layer composed of the IZO film were formed by sputtering so as to be laminated in this order. In this way, the optical film of Example 1 was produced. The thickness (t1 to t5) of each layer is as shown in Table 1. The thickness (t1 to t5) of each layer was measured by fluorescent X-ray analysis (ZSX-100e, manufactured by Rigaku Corporation). The thickness and the like of each layer of the optical film were measured in the same manner in the following Examples and Comparative Examples. The film forming conditions for sputtering in Example 1 are as follows.

<Film formation conditions: 1st layer, 3rd layer and 5th layer>
Target: IZO target (manufactured by JX Nippon Mining & Metals Co., Ltd.), film formation pressure: 0.4 Pa, DC power: 2.5 W / cm ²
The thicknesses (t1, t3, t5) of the first layer, the third layer, and the fifth layer were adjusted by appropriately changing the film formation time.

<Film formation conditions: 2nd layer and 4th layer>
Target: Silver (AgPd) containing 1 atomic% of palladium, film formation pressure: 0.4 Pa, DC power: 0.6 W / cm ²
The thicknesses (t2, t4) of the second layer and the fourth layer were adjusted by appropriately changing the film formation time.

[Examples 2 to 9]
Each optical film of Examples 2 to 9 was produced in the same manner as in Example 1 except that the thickness of each layer was changed to the value shown in Table 1.

[Comparative Example 1]
An optical film of Comparative Example 1 was produced in the same manner as in Example 1 except that the thickness of each layer was changed to the value shown in Table 1.

[Comparative Example 2]
At the time of forming the first layer, the third layer and the fifth layer, an SZO target (ZnO containing 5 atomic% of Ti, manufactured by AGC Ceramic Co., Ltd.) was used, and the film forming conditions were set to a film forming pressure of 0.4 Pa and DC. The optical film of Comparative Example 2 was produced in the same manner as in Example 1 except that the power was set to 2.5 W / cm ^{2 and the thickness of each layer was changed to the values shown in Table 1.}

[Comparative Example 3]
At the time of forming the first layer, the third layer and the fifth layer, after using the Nb ₂ O ₅ target (manufactured by Mitsubishi Materials Corporation), the film formation conditions were set to a film formation pressure of 0.4 Pa and a DC power of 2.5 W / cm. The optical film of Comparative Example 3 was produced in the same manner as in Example 1 except that the thickness was set to ^{2 and the thickness of each layer was changed to the value shown in Table 1.}

[Comparative Example 4]
When forming the first layer, the third layer, and the fifth layer, an ITO target (manufactured by Mitsui Mining & Smelting Co., Ltd.) was used, and the film formation conditions were set to a film formation pressure of 0.4 Pa and a DC power of 2.5 W / cm ² . The optical film of Comparative Example 4 was produced in the same manner as in Example 1 except that the thickness of each layer was changed to the value shown in Table 1.

[Evaluation 1: Total light transmittance]
For each optical film of each Example and each Comparative Example, the total light transmittance (%) was measured according to JIS K 7361-1. The total light transmittance (%) is the transmittance of light from the fifth layer side toward the resin film side in each optical film. The results are shown in Table 1.

[Evaluation 2: Visible light reflectance]
For each optical film of each Example and each Comparative Example, the visible light reflectance (%) on the fifth layer side was measured according to JIS R 3106. The results are shown in Table 1.

[Evaluation 3: Heat ray shielding rate]
For each optical film of each example and each comparative example, the solar transmittance (%) of each optical film was measured in accordance with JIS R 3106, and the value obtained by subtracting the solar transmittance (%) from 100 (%). Was defined as the heat ray shielding rate (%) of each optical film. The solar transmittance (%) is the transmittance of solar radiation from the fifth layer side toward the resin film side in each optical film. The results are shown in Table 1.

[Evaluation 4: Reflected chromaticity]
For each optical film of each Example and each Comparative Example, 10 degrees from the normal direction on the 5th layer side using a D65 light source while complying with JIS Z8781-1: 2012 (CIE Lab color system). The reflected chromaticity (cci) (a ^* ) when viewed from an inclined direction was determined. The results are shown in Table 1.

As shown in Table 1, the optical films of Examples 1 to 9 have a total light transmittance of 70% or more, a visible light reflectance of 10% or less, and a heat ray shielding rate of 50% or more. The reflectance chromaticity (a ^* ) was 5 or less. These optical films are excellent in visible light transmittance and heat ray reflection, and have reduced redness. The refractive index of IZO of each example in light having a wavelength of 550 nm is 2.02.

In the optical films of Examples 1 to 9, an IZO film is used as the optical adjustment layer (first layer, third layer, and fifth layer). The IZO film is amorphous, and a smooth film surface can be easily obtained as compared with an optical adjustment layer (SZO film, Nb ₂ O _{5 film, ITO film) made of other materials.} Therefore, when a heat ray reflecting layer (second layer, fourth layer) made of an AgPd film is laminated on such an optical adjustment layer (IZO film), a smooth interface is likely to be formed between them. Therefore, in Examples 1 to 9, it is presumed that high visible light transmittance and heat shielding performance (heat ray reflectivity) are obtained as described above.

Further, the IZO film is less affected by outgas, which is a problem when a resin film is used as a base material. This is because the IZO film can be formed into an optically transparent and flat shape even under low temperature conditions in which the generation of outgas is suppressed.

Comparative Example 1 is a case where the first layer, the third layer, and the fifth layer are made of IZO as in Example 1, but the thickness (t2) of the second layer is too small. The optical film of Comparative Example 1 had a reflected chromaticity (a ^* ) of 5.7, and had a slightly reddish color. Further, the optical film of Comparative Example 1 had a low total light transmittance and a high visible light reflectance.

In Comparative Example 2, the first layer, the third layer, and the fifth layer are made of SZO, and the ratio (t1 / t2) of the thickness (t1) of the first layer to the thickness (t2) of the second layer is 3.18. (That is, when t1 is too large for t2). The refractive index of SZO in light having a wavelength of 550 nm is 2.10. The optical film of Comparative Example 2 had a reflected chromaticity (a ^* ) of 15.1 and had a considerably reddish color. Further, the optical film of Comparative Example 2 had a low total light transmittance.

In Comparative Example 3, the first layer, the third layer, and the fifth layer are composed of Nb ₂ O ₅ (indicated as “NBO” in Table 1), and when t1 / t2 = 1.36 (that is, in t2). On the other hand, when t1 is too small). The refractive index _{of Nb 2} O _{5 in} light having a wavelength of 550 nm is 2.35. The optical film of Comparative Example 3 had a reflected chromaticity (a ^* ) of 10.5, and had a considerably reddish color. Further, the optical film of Comparative Example 3 had a low total light transmittance and a high visible light reflectance.

Comparative Example 4 is a case where the first layer, the third layer, and the fifth layer are made of ITO, and the refractive index of ITO in light having a wavelength of 550 nm is 1.92, which is too small. The optical film of Comparative Example 4 had a reflective chromaticity (a ^* ) of -4.3, suppressed redness, and had a high total light transmittance, but a low heat ray reflectance.

1,1A ... Optical film, 2 ... Resin film, 3 ... Underlayer, 11 ... 1st layer, 12 ... 2nd layer, 13 ... 3rd layer, 14 ... 4th layer, 15 ... 5th layer

Claims (7)

With a transparent resin film
A first layer composed of an oxide arranged on the resin film and having a refractive index of 1.95 or more and 2.08 or less in light having a wavelength of 550 nm.
A second layer, which is arranged on the first layer and is made of silver or a silver alloy,
The third layer, which is arranged on the second layer and is composed of the oxide, and
A fourth layer arranged on the third layer and made of the silver or the silver alloy,
An optical film arranged on the fourth layer and provided with a fifth layer made of the oxide.
The thickness of the first layer (t1), the thickness of the second layer (t2), the thickness of the third layer (t3), the thickness of the fourth layer (t4), and the thickness of the fifth layer (t5). However, the optical film is characterized by satisfying the following conditions (A) to (F).
(A) t2 ≧ 6.0 (nm)
(B) t2 ≤ t4
(C) (t2 + t4) ≤25.0 (nm)
(D) 2.15 ≦ t1 / t2 ≦ 3.00
(E) t1 ≦ t5 <t3
(F) (t1 + t3 + t5) ≤150.0 (nm) The optical film according to claim 1, wherein the oxide is IZO. The optical film according to claim 1 or 2, further comprising a base layer made of silicon oxide, which is interposed between the resin film and the first layer. The optical film according to any one of claims 1 to 3, wherein the total light transmittance is 70% or more. The optical film according to any one of claims 1 to 4, wherein the visible light reflectance is 10% or less. The optical film according to any one of claims 1 to 5, wherein the heat ray shielding rate is 50% or more and the reflected chromaticity (a ^{*) is 5.0 or less.} The optical film according to any one of claims 1 to 6.
A base material with an optical film, wherein the optical film is laminated and includes a transparent base material that supports the optical film.

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