KR102522225B1 - Polarizing film, protective plate for image display device, and retardation film - Google Patents

Abstract

The polarizing film includes a first transparent resin film, an infrared reflective layer, and a polarizer in order on one side in the thickness direction, and the infrared reflective layer includes a first inorganic oxide layer, a metal layer, and a second inorganic oxide layer in this order. do.

Description

Polarizing film, protective plate for image display device, and retardation film

The present invention relates to a polarizing film, a retardation film, and a protective plate for an image display device, and more particularly, to a polarizing film, a retardation film, and a protective plate for an image display device preferably used for optical applications.

As a digital signage or information display, a large liquid crystal display is widely used. Since these large liquid crystal displays are often installed outdoors, a protective plate such as a glass plate is formed on the surface for the purpose of preventing breakage. An antireflection film is formed on the surface of the protective plate in order to prevent reflection and reflection of strong external light such as sunlight and improve visibility (see Patent Document 1).

By the way, thermal damage by sunlight is mentioned as a problem other than reflection of external light in the liquid crystal image display apparatus installed outdoors. That is, there is a problem that internal components such as liquid crystal cells are excessively heated and deteriorated. Therefore, forming an infrared reflective film on the surface of a guard plate is examined (refer to Patent Document 2).

The infrared reflective film of Patent Literature 2 discloses an infrared reflective film provided with an infrared reflective layer composed of a first metal oxide layer, a metal layer, and a second metal oxide layer in this order on a transparent film substrate.

Since the infrared reflective film of Patent Literature 2 is provided with a metal layer, it exhibits good infrared reflective ability compared to other infrared reflective films.

Japanese Unexamined Patent Publication No. 11-258592 Japanese Unexamined Patent Publication No. 2014-167617

However, the infrared reflective film of Patent Literature 2 can emit not only the near-infrared region (for example, a wavelength range of 800 to 1600 nm) but also visible light, particularly visible light close to the near-infrared region (for example, a wavelength range of 600 to 800 nm). red light) is also reflected. Therefore, there is room for improvement in suppressing the reflection of external light.

In addition, when the liquid crystal image display device is left in a wet environment such as in the rain, water may enter between the infrared reflective film of Patent Document 2 and the protective plate. At that time, water is not discharged between the infrared reflective layer (particularly, the metal layer) having a low water permeability and the protective plate, and excessive water may accumulate, resulting in cloudiness inside the protective plate, causing a problem of reduced transparency. There are cases. In addition, the presence of excessively stagnant water accelerates the corrosion of the metal layer and deteriorates the appearance in some cases. In addition, deterioration of appearance due to the presence of water does not occur in an infrared reflective film made of oxide, and is a problem inherent in an infrared reflective film having a metal layer.

An object of the present invention is to provide a protective plate for an image display device, a polarizing film, and a retardation film capable of suppressing reflection of visible light of external light while reflecting infrared rays, and suppressing a decrease in transparency and deterioration of appearance in a humid environment. there is something

In the present invention [1], a first transparent resin film, an infrared reflective layer, and a polarizer are sequentially provided on one side in the thickness direction, and the infrared reflective layer includes a first inorganic oxide layer, a metal layer, and a second inorganic oxide layer It includes a polarizing film having in order.

This invention [2] contains the polarizing film as described in [1] further equipped with the 1/4 wavelength layer between the said infrared reflection layer and the said polarizer.

In the present invention [3], a second transparent resin film is further provided between the infrared reflection layer and the polarizer, and the thickness of the second transparent resin film is 10 μm or more and 100 μm or less, [1] or [2] ] The polarizing film described in is included.

This invention [4] contains the polarizing film in any one of [1]-[3] which further equips one side of the said thickness direction of the said polarizer with the 3rd transparent resin film.

The present invention [5] includes the polarizing film described in [4], wherein the third transparent resin film is an ultraviolet ray absorbing layer.

The present invention [6] includes the polarizing film according to any one of [1] to [5] further comprising a first pressure-sensitive adhesive layer between the first transparent resin film and the infrared reflective layer.

This invention [7] contains the polarizing film in any one of [1]-[6] whose water vapor transmission rate of the said 1st transparent resin film is 5 g/m<2>*24h or more.

This invention [8] contains the polarizing film in any one of [1]-[7] whose said metal layer is a silver layer or a silver alloy layer.

In this invention [9], the said 1st inorganic oxide layer and the said 2nd inorganic oxide layer contain the polarizing film in any one of [1]-[8] containing an indium type oxide.

This invention [10] is the polarizing film according to any one of [1] to [9], a second pressure-sensitive adhesive layer formed on one side of the polarizing film in the thickness direction, and the thickness of the second pressure-sensitive adhesive layer A protective plate for an image display device having a transparent protective plate formed on one side of the direction is included.

In the present invention [11], a first transparent resin film, an infrared reflective layer, and a 1/4 wavelength layer are sequentially provided on one side in the thickness direction, and the infrared reflective layer includes a first inorganic oxide layer, a metal layer, and a second A retardation film comprising two inorganic oxide layers in order is included.

The present invention [12] includes the retardation film described in [11], further including a second transparent resin film, wherein the second transparent resin film has a thickness of 10 μm or more and 100 μm or less.

In the present invention [13], the retardation film according to any one of [11] or [12], characterized by further comprising a first pressure-sensitive adhesive layer between the first transparent resin film and the infrared reflective layer. contains

According to the protective plate for an image display device of the present invention provided with the polarizing film and retardation film of the present invention, infrared rays can be reflected. Therefore, it is possible to suppress the temperature rise of internal parts of the image display device and reduce deterioration of the image display device.

Moreover, since the reflection of visible light of external light can be suppressed, the reflection of external light can be reduced.

Moreover, in a humid environment, since the fogging of the guard plate for image display apparatuses can be suppressed, transparency can be maintained. Moreover, in a wet environment, corrosion of a metal layer can be suppressed and a favorable external appearance can be maintained.

1 : shows the side view of one Embodiment of a polarizing film.
2 : shows the side view of the guard plate provided with the polarizing film shown in FIG.
3 : shows the side view of the modified example of a polarizing film (embodiment in which each layer was changed).
4 : shows the side view of the modified example of a polarizing film (embodiment which does not have a 3rd adhesive layer and a 2nd transparent resin film).
Fig. 5 shows a side view of a modified example of a polarizing film (embodiment not provided with a third pressure sensitive adhesive layer, a second quarter wavelength layer, and a fourth pressure sensitive adhesive layer).
Fig. 6 shows a side view of a modified example of a polarizing film (embodiment not provided with a third pressure sensitive adhesive layer, a second transparent resin film, a second quarter wavelength layer, and a fourth pressure sensitive adhesive layer).
Fig. 7 shows a side view of a modified example of a polarizing film (embodiment not provided with a first pressure sensitive adhesive layer, a second transparent resin film, a second 1/4 wavelength layer, and a fourth pressure sensitive adhesive layer).
8 shows a modified example of a polarizing film (a first pressure-sensitive adhesive layer, a first quarter-wavelength layer, a third pressure-sensitive adhesive layer, a second transparent resin film, a second quarter-wavelength layer, a fourth pressure-sensitive adhesive layer, and a third transparent A side view of an embodiment not provided with a resin film) is shown.
9 : shows the side view of the polarizing film of a comparative example.
Fig. 10 shows a graph showing the relationship between the measured wavelength and the light reflectance measured in Examples.

1. Polarizing film

With reference to FIG. 1, one Embodiment of the polarizing film 1 of this invention is described.

1, the vertical direction of the paper is the vertical direction (thickness direction, first direction), the upper side of the paper is the upper side (one side of the thickness direction, one side of the first direction), and the lower side of the paper is the lower side (the other side of the thickness direction, the first direction). the other side of the direction). In addition, the left-right direction and the depth direction of the paper are plane directions orthogonal to the vertical direction. Specifically, it is based on the direction arrows in each drawing.

The polarizing film 1 has a film shape (including sheet shape) having a predetermined thickness, extending in a plane direction orthogonal to the thickness direction, and has a flat upper surface and a flat lower surface (two main surfaces). The polarizing film 1 is, for example, a part component with which an image display device (a liquid crystal image display device or the like) is equipped, in other words, it is not an image display device. That is, the polarizing film 1 is a component for manufacturing an image display device or the like, and is distributed alone without including an image display element such as a liquid crystal cell 19 or a light source 20 such as an LED, and is distributed in the industry. It is an available device.

Specifically, as shown in FIG. 1 , the polarizing film 1 is sequentially composed of the first transparent resin film 2, the first pressure-sensitive adhesive layer 3, the infrared reflection layer 4, and the first 1 /4 wavelength layer 5, 3rd adhesive layer 6, 2nd transparent resin film 7, polarizer 8, 2nd 1/4 wavelength layer 9, 4th adhesive layer (10) and the third transparent resin film (11). Preferably, the polarizing film 1 includes a first transparent resin film 2, a first pressure-sensitive adhesive layer 3, an infrared reflective layer 4, a first quarter wavelength layer 5, and a second 3 pressure-sensitive adhesive layer (6), second transparent resin film (7), polarizer (8), second quarter-wavelength layer (9), fourth pressure-sensitive adhesive layer (10), and third transparent resin film (11) consists of only Hereinafter, each layer is described in detail.

(First transparent resin film)

The 1st transparent resin film 2 is the lowermost layer of the polarizing film 1, and is a support material for ensuring the mechanical strength of the polarizing film 1. In addition, the first transparent resin film 2 transmits and discharges water penetrating into the inside of the polarizing film 1 or the protective plate 18 for an image display device to the outside of the polarizing film 1 (lower side in FIG. 1). It is a water permeable layer for

The first transparent resin film 2 has transparency, flexibility and moisture permeability.

Examples of the material constituting the first transparent resin film 2 include cellulose resins such as triacetyl cellulose (TAC), cyclic polyolefin resins such as cycloolefin polymers, such as acrylic resins, , phenyl maleimide resin, polycarbonate resin, polyester resin, polyimide resin, polyamide resin, polystyrene resin and the like. These materials can be used alone or in combination of two or more. From the viewpoints of transparency, mechanical strength, moisture permeability, optical isotropy, etc., cyclic polyolefin resins and cellulose resins are preferable, cellulose resins are more preferable, and TAC is still more preferable.

Moreover, the 1st transparent resin film 2 may contain well-known additives, such as a ultraviolet absorber mentioned later.

Also, the first transparent resin film 2 preferably has substantially no retardation. Substantially no retardation means that the retardation at a wavelength of 550 nm is, for example, 20 nm or less in the thickness direction, preferably 10 nm or less, more preferably 5 nm or less, still more preferably is 0 nm.

The thickness of the first transparent resin film 2 is, for example, 5 μm or more, preferably 10 μm or more, more preferably 20 μm or more, and, for example, 300 μm or less, preferably 200 μm or less. It is micrometer or less, More preferably, it is 100 micrometer or less.

In addition, the thickness of each layer (excluding the infrared reflective layer 4) of the first transparent resin film 2 or the like is determined by using, for example, a film thickness meter ("Digital Dial Gauge DG-205" manufactured by Peacock). can be measured using In addition, the thickness can also be measured by acquiring and observing a cross-sectional SEM image.

The water vapor transmission rate of the first transparent resin film 2 is, for example, 5 g/m 2 24 h or more, preferably 10 g/m 2 24 h or more, more preferably 30 g/m 2 24 h or more, still more preferably is 50 g/m 2 24 h or more, particularly preferably 100 g/m 2 24 h or more, and, for example, 5000 g/m 2 24 h or less, preferably 3000 g/m 2 24 h or less, more preferably is 1500 g/m 2 24 h or less, more preferably 1000 g/m 2 24 h or less, particularly preferably 800 g/m 2 24 h or less. By making the moisture permeability equal to or more than the lower limit, water penetrating into the inside of the polarizing film (1), in particular, water penetrating between the first transparent resin film (2) and the infrared reflective layer (4) can be quickly discharged to the outside, Retention of water between them can be suppressed. As a result, cloudiness of the polarizing film 1 and corrosion of the metal layer 13 can be suppressed. On the other hand, by setting the water vapor transmission rate below the above upper limit, excessive penetration of water between the first transparent resin film 2 and the infrared reflective layer 4 can be prevented, and corrosion of the metal layer 13 can be suppressed.

The water vapor transmission rate can be measured by a test according to JIS K 7129:2008 Annex B, for example. Specifically, it can be obtained by using a measuring device "PERMATRAN W3/33" manufactured by MOCON, and the test conditions are 40°C and 90% relative humidity.

Moreover, surface treatment may be given to the lower surface of the 1st transparent resin film 2 as needed. As the surface treatment, etching treatment such as sputtering, corona discharge, flame, ultraviolet irradiation, electron beam irradiation, chemical conversion, oxidation, or undercoating treatment can be performed, for example. In addition, the first transparent resin film 2 can be dust-removed and cleaned by solvent cleaning, ultrasonic cleaning, or the like.

(1st adhesive layer)

The first pressure-sensitive adhesive layer (3) adheres the first transparent resin film (2) and the infrared reflective layer (4), and further removes water present on the surface of the infrared reflective layer (4) to the first transparent resin film (2). It is a layer for discharging to the outside through or through the end of the first pressure-sensitive adhesive layer (3). The first pressure-sensitive adhesive layer 3 has a film shape (including a sheet shape), and is disposed so as to contact the upper surface of the first transparent resin film 2 over the entire upper surface of the first transparent resin film 2. has been

The 1st adhesive layer 3 is prepared with the adhesive composition. The composition of the pressure-sensitive adhesive composition is not limited, but examples thereof include acrylic pressure-sensitive adhesives, rubber-based pressure-sensitive adhesives (butyl rubber, etc.), silicone-based pressure-sensitive adhesives, polyester-based pressure-sensitive adhesives, polyurethane-based pressure-sensitive adhesives, polyamide-based pressure-sensitive adhesives, epoxy-based pressure-sensitive adhesives, and vinylalkyl ether-based pressure-sensitive adhesives. , fluororesin-based adhesives and the like, preferably acrylic-based adhesives are exemplified from the viewpoints of adhesiveness and moisture permeability.

The pressure-sensitive adhesive composition may contain, for example, additives such as a filler, antioxidant, softener, thixotropic agent, lubricant, pigment, antiscorch agent, stabilizer, ultraviolet absorber, colorant, antifog agent, and flame retardant.

The pressure-sensitive adhesive composition preferably contains an antioxidant. Although the antioxidant is not limited, Preferably a benzotriazole type compound is mentioned. Examples of the benzotriazole-based compound include 1,2,3-benzotriazole, 5-methyl-1H-benzotriazole, 4-methylbenzotriazole, and nitrobenzotriazole. Content of antioxidant with respect to an adhesive composition is 0.01 mass % or more and 10 mass % or less, for example.

The thickness of the first pressure-sensitive adhesive layer 3 is, for example, 1 μm or more, preferably 5 μm or more, more preferably 10 μm or more, and, for example, 300 μm or less, preferably 150 μm. or less, more preferably 50 μm or less. By making the thickness of the 1st adhesive layer 3 more than the said lower limit, it is excellent in bondability. Moreover, it is excellent in handleability by making the thickness of the 1st adhesive layer 3 below the said upper limit.

The thickness of the pressure-sensitive adhesive layers such as the first pressure-sensitive adhesive layer 3 can be measured using, for example, a film thickness gauge (“Digital Dial Gauge DG-205” manufactured by Peacock). In addition, the thickness can also be measured by acquiring and observing a cross-sectional SEM image.

(Infrared Reflective Layer)

The infrared reflecting layer 4 is a layer for transmitting visible light while reflecting infrared rays incident on the polarizing film 1 .

The infrared reflective layer 4 has a film shape (including a sheet shape), and is disposed so as to contact the upper surface of the first pressure sensitive adhesive layer 3 over the entire upper surface of the first pressure sensitive adhesive layer 3 .

The infrared reflective layer 4 includes a first inorganic oxide layer 12, a metal layer 13, and a second inorganic oxide layer 14 sequentially from the bottom. In short, the infrared reflective layer 4 includes the first inorganic oxide layer 12 disposed above the first pressure-sensitive adhesive layer 3, the metal layer 13 disposed above the first inorganic oxide layer 12, A second inorganic oxide layer 14 disposed above the metal layer 13 is provided. In addition, the infrared reflective layer 4 is preferably composed of only the first inorganic oxide layer 12, the metal layer 13, and the second inorganic oxide layer 14.

The thickness of the infrared reflective layer 4, that is, the total thickness of the first inorganic oxide layer 12, the metal layer 13 and the second inorganic oxide layer 14 is, for example, 20 nm or more, preferably 60 nm or more, and, for example, 150 nm or less, preferably 120 μm or less, and more preferably 100 nm or less.

(1st inorganic oxide layer)

The first inorganic oxide layer 12, together with the second inorganic oxide layer 14 described later, is an optical adjustment layer for suppressing the visible light reflection of the metal layer 13 and improving the visible light transmittance of the infrared reflection layer 4. .

In addition, it is also a barrier layer for preventing deterioration of the metal layer 13 due to penetration of components such as hydrogen and carbon contained in the first transparent resin film 2 or the first pressure-sensitive adhesive layer 3 into the metal layer 13. do.

The first inorganic oxide layer 12 is the lowermost layer in the infrared reflection layer 4 and has a film shape (including a sheet shape), and the first pressure sensitive adhesive layer 3 covers the entire upper surface of the first pressure sensitive adhesive layer 3. It is arranged so as to contact the upper surface of the layer (3).

Examples of the inorganic oxide forming the first inorganic oxide layer 12 include In, Sn, Zn, Ga, Sb, Ti, Si, Zr, Mg, Al, Au, Ag, Cu, Pd, W, and metal oxides formed from at least one metal selected from the group consisting of Fe, Pb, Ni, Nb, and Cr. Metal oxides can be further doped with metal atoms shown in the above group as needed.

The inorganic oxide is preferably an oxide containing indium oxide (indium-based oxide) from the viewpoint of ensuring excellent transparency, more preferably an indium tin composite oxide (ITO). "ITO" in this specification should just be a composite oxide containing at least indium (In) and tin (Sn), and may contain additional components other than these. Examples of the additional component include metal elements other than In and Sn, and examples thereof include metal elements shown in the above groups and combinations thereof. The content of the additional component is not particularly limited, but is, for example, 5% by mass or less.

The content of tin oxide (SnO ₂ ) contained in ITO is, for example, 0.5% by mass or more, preferably 3% by mass or more, relative to the total amount of tin oxide and indium oxide (In ₂ O ₃ ), and For example, it is 35 mass % or less, Preferably it is 20 mass % or less. The content of indium oxide (In ₂ O ₃ ) is the remainder of the content of tin oxide (SnO ₂ ). By setting the content of tin oxide (SnO ₂ ) contained in ITO within the above range, the crystallinity of the ITO film can be adjusted.

The first inorganic oxide layer 12 may be crystalline or amorphous. It is preferably amorphous. This can reduce problems in the manufacturing process (for example, a heating process for obtaining crystalline quality).

The thickness of the first inorganic oxide layer 12 is, for example, 5 nm or more, preferably 20 nm or more, and, for example, 100 nm or less, preferably 60 nm or less. When the thickness of the first inorganic oxide layer 12 is within the above range, it is easy to adjust the visible light transmittance of the infrared reflective layer 4 to a high level. The thickness of the first inorganic oxide layer 12 is measured by, for example, cross-sectional observation with a transmission electron microscope (TEM).

(metal layer)

The metal layer 13 is a layer for reflecting infrared rays and imparting transparency (visible light transmittance) together with the first inorganic oxide layer 12 and the second inorganic oxide layer 14 .

The metal layer 13 has a film shape (including sheet shape), and is disposed so as to contact the upper surface of the first inorganic oxide layer 12 and the upper surface of the first inorganic oxide layer 12 .

The metal forming the metal layer 13 is not limited as long as it is a metal with high infrared reflectance, but examples include Ti, Si, Nb, In, Zn, Sn, Au, Ag, Cu, Al, Co, Cr, and Ni. made of one metal selected from the group consisting of Pb, Pd, Pt, Cu, Ge, Ru, Nd, Mg, Ca, Na, W, Zr, Ta, and Hf, or two or more metals thereof. alloys containing

As the metal, from the viewpoint of exhibiting excellent infrared reflectivity, silver (Ag) and silver alloys are preferably used, and silver alloys are more preferably used.

The silver alloy contains silver as a main component and other metals as subcomponents. The metal element of the subcomponent is not limited. Examples of the silver alloy include Ag-Cu alloy, Ag-Pd alloy, Ag-Pd-Cu alloy, Ag-Pd-Cu-Ge alloy, Ag-Cu-Au alloy, Ag-Cu-In alloy, Ag -Cu-Sn alloy, Ag-Ru-Cu alloy, Ag-Ru-Au alloy, Ag-Nd alloy, Ag-Mg alloy, Ag-Ca alloy, Ag-Na alloy, Ag-Ni alloy, Ag-Ti alloy, Ag-In alloy, Ag-Sn alloy, etc. are mentioned. From a durable viewpoint, as a silver alloy, Preferably, Ag-Cu alloy, Ag-Cu-In alloy, Ag-Cu-Sn alloy, Ag-Pd alloy, Ag-Pd-Cu alloy, etc. are mentioned.

The silver content in the silver alloy is, for example, 80% by mass or more, preferably 90% by mass or more, and is, for example, 99.9% by mass or less. The content ratio of other metals in the silver alloy is the remainder of the above-mentioned content ratio of silver.

The thickness of the metal layer 13 is, for example, 1 nm or more, preferably 5 nm or more, more preferably 10 nm or more, still more preferably 14 nm or more, from the viewpoint of infrared reflectivity and transparency, and For example, it is 80 nm or less, preferably 30 nm or less, more preferably 25 nm or less, still more preferably 20 nm or less, and particularly preferably 15 nm or less. Especially when the thickness of the metal layer 13 is 14 nm or more and 80 nm or less, the deterioration of the external appearance by a wet environment can be further suppressed. The thickness of the metal layer 13 is measured by, for example, cross-sectional observation with a transmission electron microscope (TEM).

(Second Inorganic Oxide Layer)

The second inorganic oxide layer 14, together with the first inorganic oxide layer 12, is an optical adjustment layer for suppressing the visible light reflectance of the metal layer 13 and improving the visible light transmittance of the infrared reflection layer 4. Moreover, the 2nd inorganic oxide layer 14 is a barrier layer for preventing deterioration of the metal layer 13 by penetration of external oxygen, moisture, etc. into the metal layer 13.

The second inorganic oxide layer 14 is the uppermost layer in the infrared reflection layer 4 and has a film shape (including sheet shape), covering the entire upper surface of the metal layer 13. placed in contact with.

The inorganic oxide forming the second inorganic oxide layer 14 includes the inorganic oxides exemplified for the first inorganic oxide layer 12, preferably contains indium oxide, and more preferably is made of ITO.

When the 2nd inorganic oxide layer 14 consists of ITO, content of tin oxide ( _SnO2 ) contained in ITO is the same as that of the 1st inorganic oxide layer 12.

The second inorganic oxide layer 14 may be crystalline or amorphous. It is preferably amorphous from the viewpoint of being able to reduce problems in the manufacturing process (for example, a high-temperature heating process for obtaining crystalline quality). Moreover, from a viewpoint of moisture resistance, Preferably it is semi-crystalline which contains crystal grains in an amorphous film.

The thickness of the second inorganic oxide layer 14 is, for example, 5 nm or more, preferably 20 nm or more, and, for example, 100 nm or less, preferably 60 nm or less. When the thickness of the second inorganic oxide layer 14 is within the above range, it is easy to adjust the visible light transmittance of the infrared reflective layer 4 to a high level. The thickness of the second inorganic oxide layer 14 is measured by, for example, cross-sectional observation with a transmission electron microscope (TEM).

The ratio (T2/T1) of the thickness T2 of the second inorganic oxide layer 14 to the thickness T1 of the first inorganic oxide layer 12 (T2/T1) is, for example, 0.5 or more, preferably 0.75 or more, and, for example, For example, it is 1.5 or less, preferably 1.25 or less. When the ratio (T2/T1) is within the above range, deterioration of the metal layer 13 in a wet environment can be further suppressed.

The ratio (T2/T3) of the thickness T2 of the second inorganic oxide layer 14 to the thickness T3 of the metal layer 13 is, for example, 1.5 or more, preferably 2.0 or more, more preferably 3.0 or more, , and, for example, 10 or less, preferably 4.0 or less.

(1st 1/4 wavelength layer)

The first quarter-wavelength layer 5 is a layer for converting linearly polarized light that has passed through a polarizer 8 described later into substantially circularly polarized light.

The first 1/4 wavelength layer 5 has a film shape (including a sheet shape), and is disposed so as to contact the entire upper surface of the infrared reflective layer 4 with the upper surface of the infrared reflective layer 4 .

The retardation of the first quarter wavelength layer 5 at a wavelength of 550 nm is, for example, in the range of 137.5 nm ± 40 nm, preferably in the range of 137.5 nm ± 20 nm, more preferably 137.5 nm. It is in the range of ± 10 nm.

Further, the angle between the direction of the slow axis of the first quarter-wavelength layer 5 and the direction of the absorption axis of the polarizer 8 is, for example, in the range of 45° ± 10°, preferably 45° ± 10°. range of 2°.

As the first quarter-wavelength layer 5, specifically, a stretched film obtained by stretching a resin film, a film obtained by orientation treatment of a liquid crystal polymer, and the like are exemplified. Cyclic polyolefin resins, such as a cycloolefin polymer, polycarbonate resin, etc. are mentioned as a material of a resin film.

The thickness of the first quarter-wavelength layer 5 is, for example, 3 μm or more, preferably 10 μm or more, and, for example, 300 μm or less, preferably 100 μm or less.

(Third pressure sensitive adhesive layer)

The third pressure-sensitive adhesive layer 6 is a layer for bonding the first quarter-wavelength layer 5 and the second transparent resin film 7 together.

The third pressure-sensitive adhesive layer 6 has a film shape (including a sheet shape), and covers the entire upper surface of the first quarter-wavelength layer 5. placed in contact with.

The 3rd adhesive layer 6 is prepared with the adhesive composition. Examples of the pressure-sensitive adhesive composition include the pressure-sensitive adhesive composition described above in the first pressure-sensitive adhesive layer 3, preferably an acrylic pressure-sensitive adhesive.

The thickness of the third pressure sensitive adhesive layer 6 is, for example, 1 μm or more, preferably 5 μm or more, and, for example, 300 μm or less, preferably 150 μm or less, more preferably 50 μm or less. below By making the thickness of the 3rd adhesive layer 6 more than the said lower limit, it is excellent in bondability. Moreover, it is excellent in moisture permeability by making the thickness of the 3rd adhesive layer 6 below the said upper limit.

(Second transparent resin film)

The second transparent resin film 7 is a layer that supports the polarizer 8 (described later). Moreover, it is also a layer which reduces the quality change of the polarizer 8 in a heat environment by distributing or passing the water contained in the polarizer 8 inside the 2nd transparent resin film 7. In addition, the distance between the infrared reflective layer 4 and the transparent protective plate 17 (described later) is increased, and the water stored on the surface of the infrared reflective layer 4 is dispersed inside the second transparent resin film 7, or It is also a layer for suppressing cloudiness and corrosion of the metal layer 13 by removing water through the edge of the second transparent resin film 7.

The second transparent resin film 7 has a film shape (including sheet shape) and is disposed so as to contact the entire upper surface of the third pressure sensitive adhesive layer 6 and the upper surface of the third pressure sensitive adhesive layer 6. there is.

The materials constituting the second transparent resin film 7 include the materials described above for the first transparent resin film 2, preferably cyclic polyolefin resins and cellulose resins, more preferably A cellulose resin is mentioned, TAC is mentioned more preferably.

Moreover, the 2nd transparent resin film 7 may contain well-known additives, such as a ultraviolet absorber mentioned later.

The thickness of the second transparent resin film 7 is, for example, 3 μm or more, preferably 10 μm or more, and, for example, 200 μm or less, preferably 100 μm or less. By making the thickness of the 2nd transparent resin film 7 more than the said lower limit, it has the function of supporting the polarizer 8. Moreover, by carrying out thickness below the said upper limit, sufficient moisture permeability can be maintained and it is easy to suppress the quality change of the polarizer 8 in a thermal environment.

The water vapor transmission rate of the second transparent resin film 7 is, for example, 5 g/m 2 24 h or more, preferably 10 g/m 2 24 h or more, more preferably 30 g/m 2 24 h or more, still more preferably is 50 g/m 2 24 h or more, particularly preferably 100 g/m 2 24 h or more, and, for example, 5000 g/m 2 24 h or less, preferably 3000 g/m 2 24 h or less, more preferably is 1500 g/m 2 24 h or less, more preferably 1000 g/m 2 24 h or less, particularly preferably 800 g/m 2 24 h or less. By making the water vapor transmission rate of the 2nd transparent resin film 7 into the said range, the quality change of the polarizer 8 in a thermal environment can be reduced effectively.

(polarizer)

The polarizer 8 is a layer for converting light into linearly polarized light.

The polarizer 8 has a film shape (including a sheet shape), and is disposed so as to contact the entire upper surface of the second transparent resin film 7 with the upper surface of the second transparent resin film 7 .

As the polarizer 8, a dichroic substance (iodine, dichroic dye) is adsorbed to a hydrophilic resin film such as a polyvinyl alcohol film (PVA) or an ethylene-vinyl acetate copolymer partially saponified film, for example, and a uniaxial Stretched films and the like are exemplified. Moreover, polyethylene-type films, such as the dehydration process material of polyvinyl alcohol and the dehydrochlorination process material of polyvinyl chloride, etc. are mentioned.

The thickness of the polarizer 8 is, for example, 1 μm or more, preferably 3 μm or more, more preferably 5 μm or more, and, for example, 200 μm or less, preferably 100 μm or less, and more It is preferably 50 μm or less, more preferably 30 μm or less.

(2nd 1/4 wavelength layer)

The second quarter-wavelength layer 9 is a layer for emitting light incident from the light source 20 to the polarizer 8 as circularly polarized light.

The second quarter-wavelength layer 9 has a film shape (including sheet shape), and is disposed so as to contact the entire upper surface of the polarizer 8 with the upper surface of the polarizer 8 .

The second quarter-wavelength layer 9 should just convert linearly polarized light passing through the polarizer 8 into substantially circularly polarized light, and the same ones as the first quarter-wavelength layer 5 can be cited.

(4th pressure sensitive adhesive layer)

The fourth pressure-sensitive adhesive layer 10 is a layer for bonding the second quarter-wavelength layer 9 and the third transparent resin film 11 together.

The fourth pressure-sensitive adhesive layer 10 has a film shape (including sheet shape), and covers the entire upper surface of the second quarter-wavelength layer 9 on the upper surface of the second quarter-wavelength layer 9. placed in contact with.

The 4th adhesive layer 10 is prepared with the adhesive composition. Examples of the pressure-sensitive adhesive composition include the pressure-sensitive adhesive composition described above in the first pressure-sensitive adhesive layer 3, preferably an acrylic pressure-sensitive adhesive.

The thickness of the fourth pressure-sensitive adhesive layer 10 is, for example, 1 μm or more, preferably 5 μm or more, and, for example, 300 μm or less, preferably 150 μm or less, more preferably 50 μm or less. below

(Third transparent resin film)

The 3rd transparent resin film 11 is an ultraviolet-ray absorption layer for absorbing the ultraviolet-ray of external light and reducing deterioration of the polarizer 8.

The third transparent resin film 11 is the uppermost layer of the polarizing film 1, has a film shape (including sheet shape), and covers the entire upper surface of the fourth pressure sensitive adhesive layer 10 with a fourth pressure sensitive adhesive layer ( 10) is arranged to contact the upper surface of

The third transparent resin film 11 has ultraviolet ray absorbing properties. Specifically, it contains, for example, a transparent resin film and an ultraviolet absorber.

The material constituting the transparent resin film includes the materials described above in the first transparent resin film 2, preferably a cellulose resin, and more preferably TAC or the like.

The material of the ultraviolet absorber is not limited, but examples thereof include benzotriazole-based compounds, hydroxyphenyltriazine-based compounds, benzophenone-based compounds, salicylic acid ester-based compounds, cyanoacrylate-based compounds, and nickel complex salt-based compounds. there is.

The content of the ultraviolet absorber is, for example, 0.001% by mass or more, preferably 0.1% by mass or more, and, for example, 20% by mass or less, preferably, with respect to the total amount of the third transparent resin film 11. is 5% by mass or less.

The third transparent resin film 11 preferably has substantially no retardation.

The thickness of the third transparent resin film 11 is, for example, 1 μm or more, preferably 5 μm or more, more preferably 10 μm or more, and, for example, 300 μm or less, preferably 100 μm or less. μm or less, more preferably 70 μm or less.

(Method for producing polarizing film)

Next, a method for manufacturing the polarizing film 1 is explained. In order to manufacture the polarizing film 1, each said layer is arrange|positioned (laminated) in the above-mentioned order, for example.

Specifically, for example, (1) a first transparent resin film (2), (2) a first laminate composed of an infrared reflective layer (4) and a first quarter wavelength layer (5), (3) a second transparent A second laminate composed of a resin film (7), a polarizer (8), and a second quarter-wavelength layer (9), (4) and a third transparent resin film (11) are prepared, respectively, and these are prepared as an adhesive layer (first The pressure-sensitive adhesive layer (3), the third pressure-sensitive adhesive layer (6), and the fourth pressure-sensitive adhesive layer (10) are interposed therebetween.

As the first transparent resin film 2, the second laminate, and the third transparent resin film 11, known or commercially available ones can be used.

In the first laminate, for example, an infrared reflective layer 4 is laminated on one side of a known or commercially available first quarter-wavelength layer 5 by a dry process.

Specifically, each of the second inorganic oxide layer 14, the metal layer 13, and the first inorganic oxide layer 12 is sequentially dried on one side of the first quarter-wavelength layer 5. place

As a dry method, a vacuum deposition method, a sputtering method, an ion plating method, etc. are mentioned, for example. A sputtering method is preferred. Specifically, a magnetron sputtering method is exemplified.

Examples of the gas used in the sputtering method include inert gases such as Ar. Moreover, reactive gases, such as oxygen, can be used together as needed. In the case of using a reactive gas together, the flow rate of the reactive gas is not particularly limited, and the ratio of the flow rate of the reactive gas to the flow rate of the inert gas is, for example, 0.1/100 or more, preferably 1/100 or more. , and is, for example, 5/100 or less.

Specifically, in the formation of the first inorganic oxide layer 12 and the second inorganic oxide layer 14, an inert gas and a reactive gas are preferably used together as the gas. In formation of the metal layer 13, as a gas, an inert gas is preferably used alone.

In the case of adopting the sputtering method, the above inorganic oxides or metals constituting each layer can be used as the target material.

The power supply used in the sputtering method is not limited, and examples thereof include single use or combined use of a DC power supply, an MF/AC power supply, and an RF power supply, and preferably a DC power supply.

In this way, an infrared reflective layer 4 in which the second inorganic oxide layer 14, the metal layer 13, and the first inorganic oxide layer 12 are formed in this order is formed on one side of the first quarter-wavelength layer 5. Thus, the first laminate is obtained.

In addition, the 1st inorganic oxide layer 12 and the 2nd inorganic oxide layer 14 obtained by dry process are amorphous. Therefore, you may heat-process in order to crystallize them as needed.

Next, each film and laminate are placed through the pressure-sensitive adhesive layer.

The pressure-sensitive adhesive layer may be disposed by, for example, coating and drying a liquid pressure-sensitive adhesive composition on one side of each film or laminate, or a sheet-like pressure-sensitive adhesive composition (pressure-sensitive adhesive layer) on one side of each film or laminate. You can place it as is.

Thereby, the polarizing film 1 is obtained.

The total thickness of the polarizing film 1 is, for example, 2 μm or more, preferably 20 μm or more, more preferably 50 μm or more, still more preferably 100 μm or more, and, for example, 1000 μm or less, preferably 500 μm or less, more preferably 300 μm or less, still more preferably 200 μm or less, and particularly preferably 150 μm or less.

In this polarizing film 1, the average reflectance of near-infrared rays with a wavelength of 800 to 1600 nm is, for example, 10% or more, preferably 20% or more, more preferably 30% or more, and, for example, , 100% or less.

The visible light transmittance of the polarizing film 1 is, for example, 60% or more, preferably 80% or more, more preferably 85% or more, and, for example, 95% or less.

(action effect)

This polarizing film 1 is equipped with the 1st transparent resin film 2, the infrared reflecting layer 4, and the polarizer 8 in this order. Moreover, the infrared reflective layer 4 is equipped with the 1st inorganic oxide layer 12, the metal layer 13, and the 2nd inorganic oxide layer 14 in this order.

For this reason, since the metal layer 13 has excellent reflectance in the near-infrared region (particularly 800 to 1600 nm), temperature rise of internal parts (such as the liquid crystal cell 19) due to external light is suppressed, and deterioration of the image display device is prevented. can reduce

Moreover, this polarizing film 1 can also suppress reflected light of visible light (eg, 600-800 nm) of visible light region, especially infrared region vicinity. Specifically, the infrared reflection layer 4 slightly reflects visible light (for example, 600 to 800 nm) in the vicinity of the near infrared region. However, in this polarizing film 1, in the image display device, since the infrared reflective layer 4 is disposed on the liquid crystal cell 19 side (opposite to the protective plate 18) rather than the polarizer 8, the infrared reflective layer ( The external light that is reflected in 4) and returns to the viewing side passes through the polarizer 8 and becomes linearly polarized light in which a part of the light is absorbed. Therefore, external light returning to the viewing side is reduced, and the reflection of external light can be reduced. In addition, in the polarizing film 1 in which the first quarter wavelength layer 5 is disposed between the polarizer 8 and the infrared reflection layer 4, external light reflected in the infrared reflection layer 4 and returned to the viewing side Silver is absorbed by the polarizer 8 and is not emitted to the viewing side. Therefore, the redness derived from the reflected light of the infrared reflective layer 4 can be significantly reduced.

In addition, since the infrared reflective layer 4 is laminated on the first transparent resin film 2, water penetrating into the vicinity of the infrared reflective layer 4 can be properly discharged to the outside through the first transparent resin film 2. there is. Therefore, cloudiness of the polarizing film 1 and corrosion of the metal layer 13 can be suppressed. Therefore, the transparency of the polarizing film 1 can be maintained.

In particular, when the water vapor transmission rate of the first transparent resin film 2 is 5 g/m 2 24 h or more, water can be discharged to the outside more reliably. Therefore, cloudiness of the polarizing film 1 and corrosion of the metal layer 13 can be further suppressed.

Moreover, the 2nd transparent resin film 7 is provided between the infrared reflection layer 4 and the polarizer 8. In particular, when the thickness of the second transparent resin film 7 is 10 μm or more and 100 μm or less, a space in which water can be dispersed between the infrared reflective layer 4 and the polarizer 8 (the second transparent resin film Since (7)) occurs, clouding of the polarizing film 1 can be further suppressed.

Moreover, the polarizing film 1 further equips the 1st 1/4 wavelength layer 5 between the infrared reflecting layer 4 and the polarizer 8. Therefore, the reflection of external light can be suppressed more reliably. Specifically, external light is converted into circularly polarized light by the polarizer 8 and the first quarter-wavelength layer 5 . Thereafter, the circularly polarized light is reflected by the liquid crystal cell 19 and converted into linearly polarized light by the first 1/4 wavelength layer 5 again. Since the linearly polarized light (external light) at this time coincides with the absorption axis of the polarizer 8, it is completely absorbed by the polarizer 8.

Moreover, the polarizing film 1 further equips the upper side (visible side) of the polarizer 8 with the 3rd transparent resin film 11. And deterioration of the polarizer 8 can be reduced if the 3rd transparent resin film 11 is an ultraviolet absorption layer.

Moreover, the polarizing film 1 further equips the 1st adhesive layer 3 between the 1st transparent resin film 2 and the infrared reflection layer 4. For this reason, water accumulated on the surface of the infrared reflective layer 4 can be reliably discharged to the outside through the first transparent resin film 2 .

Moreover, infrared rays can be reflected more reliably as the metal layer 13 is a silver layer or a silver alloy layer.

Further, when the first inorganic oxide layer 12 and the second inorganic oxide layer 14 both contain indium-based conductive oxide, the visible light transmittance is further excellent.

In addition, among the members constituting the polarizing film 1, the portion lower than the polarizer 8, that is, the first transparent resin film 2, the first pressure-sensitive adhesive layer 3, the infrared reflective layer 4, the first 1 The /4 wavelength layer 5, the third pressure sensitive adhesive layer 6, and the second transparent resin film 7 constitute one embodiment of the retardation film 15 of the present invention. Specifically, one embodiment of the retardation film 15 includes a first transparent resin film 2, a first adhesive layer 3, an infrared reflective layer 4, and a first quarter wavelength layer 5 ), the third pressure sensitive adhesive layer 6, and the second transparent resin film 7 are provided in this order.

The retardation film 15 has a film shape (including sheet shape) with a predetermined thickness, extends in a plane direction orthogonal to the thickness direction, and has a flat upper surface and a flat lower surface (two main surfaces). The retardation film 15 is, for example, a part of an image display device (eg, a liquid crystal image display device), and is, in other words, not an image display device. That is, the polarizing film 1 is a component for manufacturing an image display device or the like, and is distributed alone without including an image display element such as a liquid crystal cell 19 or a light source 20 such as an LED, and is distributed in the industry. It is an available device.

This retardation film 15 can maintain transparency even in a wet environment while reflecting infrared rays. In addition, by arranging the polarizer 8, visible light reflection of external light can be effectively suppressed.

The polarizing film 1 and the retardation film 15 are provided in an optical device, for example. As an optical device, image display devices, such as a liquid crystal image display device, a light control device, etc. are mentioned, for example. More specifically, the polarizing film 1 and the retardation film 15 are preferably used as a protective plate 18 for an image display device disposed on the front surface (visible side) of the image display device.

2. Protection plate for image display device

An embodiment of the protective plate 18 for image display devices is shown in FIG. 2 .

As shown in FIG. 2, the guard plate 18 for image display devices is equipped with the polarizing film 1, the 2nd adhesive layer 16, and the transparent guard plate 17 sequentially from the bottom. In addition, the upper side is the visual recognition side, and the lower side is the liquid crystal cell side.

The second pressure sensitive adhesive layer 16 is a layer for bonding the polarizing film 1 and the transparent protective plate 17 together.

The second pressure-sensitive adhesive layer 16 has a film shape (including sheet shape), and is disposed so as to contact the entire upper surface of the third transparent resin film 11 with the upper surface of the third transparent resin film 11. has been

The 2nd adhesive layer 16 is prepared with the adhesive composition. Examples of the pressure-sensitive adhesive composition include the pressure-sensitive adhesive composition described above in the first pressure-sensitive adhesive layer 3, preferably an acrylic pressure-sensitive adhesive.

The thickness of the second pressure-sensitive adhesive layer 16 is, for example, 1 μm or more, preferably 5 μm or more, and, for example, 300 μm or less, preferably 150 μm or less, and more preferably 50 μm or less. below

The transparent protective plate 17 is a layer for protecting internal members of the image display device, such as the liquid crystal cell 19, against impact or contamination from the outside.

The transparent protective plate 17 has a substantially flat plate shape in plan view, and is disposed so as to contact the entire upper surface of the second pressure sensitive adhesive layer 16 with the upper surface of the second pressure sensitive adhesive layer 16 .

The transparent protective plate 17 is transparent and has appropriate thickness and mechanical strength.

Examples of the transparent protective plate 17 include a resin plate made of a hard resin such as an acrylic resin or a polycarbonate resin, such as a glass plate.

Further, a functional layer such as an antireflection layer (AR) may be formed on the upper and/or lower surfaces of the transparent protective plate 17 .

The thickness of the transparent protective plate 17 is, for example, 10 μm or more, preferably 500 μm or more, and, for example, 100 mm or less, preferably 10 mm or less, more preferably 5 mm or less. .

And the guard plate 18 for image display devices is used, being disposed facing the liquid crystal cell 19 and the light source 20 shown to the virtual line of FIG. 2, for example. Furthermore, although not shown, the liquid crystal cell 19 includes a liquid crystal layer, two polarizers sandwiching the liquid crystal layer, and a color filter.

The protective plate 18 for an image display device has a film shape (including sheet shape) having a predetermined thickness, extending in a plane direction orthogonal to the thickness direction, and has a flat upper surface and a flat lower surface (two main surfaces). . The protective plate 18 for image display devices is a part component with which an image display device (a liquid crystal image display device etc.) is equipped, for example, and, in short, is not an image display device. That is, the polarizing film 1 is a component for manufacturing an image display device or the like, and is distributed alone without including an image display element such as a liquid crystal cell 19 or a light source 20 such as an LED, and is distributed in the industry. It is an available device.

Since the protective plate 18 for image display devices is provided with the polarizing film 1, reflection of external light visible light can be suppressed, reflecting infrared rays. Moreover, transparency can be maintained also in a wet environment.

3. Variations

With reference to FIGS. 3-8, the modified example of the polarizing film 1 is demonstrated. In addition, in other embodiments, the same reference numerals are assigned to the same members as those of the embodiment of Fig. 1 described above, and detailed descriptions thereof are omitted.

In FIG. 1 , the polarizing film 1 includes, in order from the bottom, the first transparent resin film 2, the first pressure-sensitive adhesive layer 3, the infrared reflection layer 4, and the first quarter wavelength layer ( 5), the third pressure sensitive adhesive layer 6, the second transparent resin film 7, the polarizer 8, the second quarter wavelength layer 9, the fourth pressure sensitive adhesive layer 10, Although the third transparent resin film 11 is provided, for example, as shown in FIG. 3, the first quarter wavelength layer 5 and the second transparent resin film 7 may be interchanged. Further, The second quarter wavelength layer 9 and the third transparent resin film 11 may be interchanged. That is, the polarizing film 1 includes, in order from the bottom, the first transparent resin film 2, the first pressure-sensitive adhesive layer 3, the infrared reflective layer 4, the second transparent resin film 7, 3rd adhesive layer 6, 1st 1/4 wavelength layer 5, polarizer 8, 3rd transparent resin film 11, 4th adhesive layer 10, 2nd 1/ A 4-wavelength layer 9 may be provided.

In this case, the retardation film 15 shown in FIG. 3 includes, in order from the bottom, the first transparent resin film 2, the first pressure-sensitive adhesive layer 3, the infrared reflective layer 4, and the second transparent resin film 2. A resin film (7), a third pressure sensitive adhesive layer (6), and a first quarter wavelength layer (5) are provided.

The polarizing film 1 and retardation film 15 shown in FIG. 3 also exhibit the same effect as the polarizing film 1 and retardation film 15 shown in FIG.

Moreover, as shown in FIG. 4 in addition to embodiment shown in FIG. 3, the polarizing film 1 does not need to be provided with the 3rd adhesive layer 6 and the 2nd transparent resin film 7. That is, the polarizing film 1 shown in FIG. 4 includes, in order from the bottom, the first transparent resin film 2, the first adhesive layer 3, the infrared reflection layer 4, and the first quarter wavelength A layer (5), a polarizer (8), a third transparent resin film (11), a fourth pressure-sensitive adhesive layer (10), and a second quarter-wavelength layer (9) are provided.

In this case, the retardation film 15 shown in FIG. 4 includes, in order from the bottom, the first transparent resin film 2, the first pressure-sensitive adhesive layer 3, the infrared reflective layer 4, and the first 1 /4 wavelength layer 5 is provided.

The polarizing film 1 and retardation film 15 shown in FIG. 4 also exhibit the same effect as the polarizing film 1 and retardation film 15 shown in FIG. Preferably, the polarizing film 1 and the retardation film 15 shown in FIG. 1 can be further reduced by providing the second transparent resin film 7 to further reduce cloudiness and corrosion of the metal layer 13. can be heard

Moreover, as shown in FIG. 5, the polarizing film 1 does not need to be equipped with the 3rd adhesive layer 6, the 2nd 1/4 wavelength layer 9, and the 4th adhesive layer 10. That is, the polarizing film 1 shown in FIG. 5 includes, in order from the bottom, the first transparent resin film 2, the first adhesive layer 3, the infrared reflection layer 4, and the first quarter wavelength A layer (5), a second transparent resin film (7), a polarizer (8), and a third transparent resin film (11) are provided.

In addition, the retardation film 15 shown in FIG. 5, in order from the bottom, the 1st transparent resin film 2, the 1st adhesive layer 3, the infrared reflection layer 4, and the 1/4 wavelength A layer (5) and a second transparent resin film (7) are provided.

The polarizing film 1 and retardation film 15 shown in FIG. 5 also exhibit the same effect as the polarizing film 1 and retardation film 15 shown in FIG.

Moreover, as shown in FIG. 6, the polarizing film 1 includes the third pressure sensitive adhesive layer 6, the second transparent resin film 7, the second quarter wavelength layer 9, and the fourth pressure sensitive adhesive. It is not necessary to provide the layer 10. That is, the polarizing film 1 shown in FIG. 6 includes, in order from the bottom, the first transparent resin film 2, the first adhesive layer 3, the infrared reflection layer 4, and the first quarter wavelength A layer (5), a polarizer (8), and a third transparent resin film (11) are provided.

In addition, the retardation film 15 shown in FIG. 6, in order from the bottom, the 1st transparent resin film 2, the 1st adhesive layer 3, the infrared reflection layer 4, and the 1/4 wavelength layer (5).

The polarizing film 1 and retardation film 15 shown in FIG. 6 also exhibit the same effect as the polarizing film 1 and retardation film 15 shown in FIG. Preferably, the polarizing film 1 and the retardation film 15 shown in FIG. 1 can be further reduced by providing the second transparent resin film 7 to further reduce cloudiness and corrosion of the metal layer 13. can be heard

Moreover, as shown in FIG. 7, the polarizing film 1 is comprised of the 1st adhesive layer 3, the 2nd transparent resin film 7, the 2nd 1/4 wavelength layer 9, and the 4th adhesive The layer 10 may not be provided, and the first 1/4 wavelength layer 5 and the third pressure-sensitive adhesive layer 6 may be interchanged. That is, the polarizing film 1 shown in FIG. 7 includes, in order from the bottom, the first transparent resin film 2, the infrared reflective layer 4, the third adhesive layer 6, and the first quarter wavelength A layer (5), a polarizer (8), and a third transparent resin film (11) are provided.

In addition, the retardation film 15 shown in FIG. 7 includes, in order from the bottom, the first transparent resin film 2, the infrared reflective layer 4, the third adhesive layer 6, and the first quarter wavelength layer (5).

The polarizing film 1 and retardation film 15 shown in FIG. 7 also exhibit the same effect as the polarizing film 1 and retardation film 15 shown in FIG. Preferably, by providing the first pressure-sensitive adhesive layer 3 and the second transparent resin film 7, the polarizing film (1) shown in FIG. ) and retardation film 15.

Moreover, as shown in FIG. 8, the polarizing film 1 includes the first pressure-sensitive adhesive layer 3, the first quarter-wavelength layer 5, the third pressure-sensitive adhesive layer 6, and the second transparent resin. It is not necessary to provide the film 7, the 2nd quarter wavelength layer 9, the 4th adhesive layer 10, and the 3rd transparent resin film 11. That is, the polarizing film 1 shown in FIG. 8 is equipped with the 1st transparent resin film 2, the infrared reflecting layer 4, and the polarizer 8 sequentially from the bottom.

The polarizing film 1 shown in FIG. 8 also exhibits the same effect as the polarizing film 1 shown in FIG. 1 . Preferably, by providing the first pressure-sensitive adhesive layer 3 and the second transparent resin film 7, cloudiness and corrosion of the metal layer 13 can be further reduced, and the first quarter-wavelength layer By providing (5), the polarizing film 1 and retardation film 15 shown in FIG. 1 can be mentioned from a viewpoint which can reliably reduce the reflection of external light.

In addition, in the polarizing film 1 shown in FIGS. 1-8, the 3rd transparent resin film 11 was made into the ultraviolet ray absorbing layer, but, for example, the 3rd transparent resin film may be a non-ultraviolet absorbing layer. In this case, the 2nd adhesive layer 16 in the protective plate 18 for image display devices is preferably made into the adhesive layer which can absorb ultraviolet rays. Specifically, the second pressure-sensitive adhesive layer 16 contains, for example, an ultraviolet absorber. Such a protective plate 18 for an image display device also exhibits the same effect as the protective plate 18 for an image display device provided with the polarizing film 1 shown in FIGS. 1 to 8 .

Moreover, although not shown, the infrared reflection layer 4 may contain layers other than the 1st inorganic oxide layer 12, the metal layer 13, and the 2nd inorganic oxide layer 14. For example, a second metal layer and a third inorganic oxide layer may be provided on the side opposite to the metal layer 13 of the second inorganic oxide layer 14, and the second metal layer of the third inorganic oxide layer and may further include a third metal layer and a fourth inorganic oxide layer on the opposite side.

In addition, one side or both sides of the first transparent resin film 2 may be further provided with functional layers such as, for example, an antifouling layer, an adhesion layer, a water repellent layer, an antireflection layer, and an oligomer prevention layer, depending on required functions. can be applied appropriately. The functional layer preferably consists of a layer containing an organic resin.

Example

Examples and comparative examples are shown below to explain the present invention more specifically. In addition, this invention is not limited to Examples and Comparative Examples at all. In addition, the specific numerical values such as the blending ratio (content ratio), physical property value, and parameter used in the following description are the blending ratio (content ratio) corresponding to those described in the above "mode for carrying out the invention" ), physical property values, parameters, etc. can be replaced with the upper limit value (numerical value defined as “below” or “less than”) or lower limit value (numerical value defined as “above” or “exceeding”) of the corresponding description.

Example 1

As shown in FIG. 1, a TAC film (thickness of 65 μm, first transparent resin film), an acrylic pressure-sensitive adhesive layer (thickness of 23 μm, first pressure-sensitive adhesive layer), an infrared reflective layer, a λ/4 plate (thickness of 50 μm, first 1 /4 wavelength layer), acrylic adhesive layer (thickness 23 μm, third adhesive layer), TAC film (thickness 40 μm, second transparent resin film), polarizer (thickness 22 μm, iodine-impregnated PVA), λ/4 plate ( 50 μm thick, 2nd 1/4 wavelength layer), acrylic adhesive layer (23 μm thick, 4th adhesive layer), TAC film containing ultraviolet absorber (60 μm thick, 3rd transparent resin film), in this order from the bottom Laminated so as to be arranged, the polarizing film of the Example was prepared.

Further, as the infrared reflective layer, a laminate composed of amorphous ITO (thickness 40 nm, first inorganic oxide layer), silver-copper alloy (thickness 8 nm, metal layer) and amorphous ITO (thickness 40 nm, second inorganic oxide layer) used

Next, as shown in Fig. 2, an acrylic pressure-sensitive adhesive layer (thickness: 23 μm, second pressure-sensitive adhesive layer) and a low-reflection glass plate (thickness: 5 mm, transparent protective plate) were laminated in this order on the upper surface of the polarizing film, and for image display devices A protective plate was prepared.

Example 2

Except having changed the thickness of the metal layer of an infrared reflecting layer to 12 nm, it carried out similarly to Example 1, and manufactured the polarizing film and the protective plate for image display devices.

Example 3

Except having changed the thickness of the metal layer of an infrared reflecting layer to 20 nm, it carried out similarly to Example 1, and manufactured the polarizing film and the protective plate for image display devices.

Comparative Example 1

As shown in FIG. 9, a TAC film (thickness: 65 μm, first transparent resin film), an acrylic pressure-sensitive adhesive layer (thickness: 23 μm, first pressure-sensitive adhesive layer), λ/4 plate (thickness: 50 μm, first quarter wavelength) layer), polarizer (thickness 22 μm, iodine-impregnated PVA), TAC film (thickness 40 μm, second transparent resin film), acrylic adhesive layer (thickness 23 μm, third adhesive layer), λ/4 plate (thickness 50 μm) , the second 1/4 wavelength layer) and the infrared reflective layer were stacked so as to be arranged in this order from the bottom to prepare a polarizing film of a comparative example.

In addition, the same infrared reflective layer as the infrared reflective layer of Example 1 was used.

Next, in the same manner as in Example 1, an acrylic pressure-sensitive adhesive layer (thickness: 23 μm, second pressure-sensitive adhesive layer) and a low-reflection glass plate (thickness: 5 mm, transparent protective plate) were sequentially laminated on the upper surface of the polarizing film, and an image of a comparative example was obtained. A protective plate for a display device was manufactured.

(permeability)

The moisture permeability of the first transparent resin film, the second transparent resin film, and the third transparent resin film was measured at a temperature of 40°C and a relative humidity of 90% using a water vapor transmission rate measuring device ("PERMATRAN W3/33" manufactured by MOCON). conditions were measured. The water vapor permeability of each transparent resin film was 200 g/m 2 24 h or more and 800 g/m 2 24 h or less.

(reflectivity)

Visible light and infrared light were irradiated to the protective plate for image display devices of each Example and Comparative Example using a spectrophotometer ("U-4100", manufactured by Hitachi High-Technologies Corporation), and the light reflectance at each wavelength was measured. . A graph at this time is shown in FIG. 10 . Moreover, Table 1 shows the average reflectance (average value of reflectance at a wavelength of 5 nm pitch) in the near-infrared region in the range of 800 to 1600 nm.

As is clear from FIG. 10 , in the polarizing films of Examples 1 and 2, reflection of visible light (particularly, red light having a wavelength of 600 to 800 nm) is reduced with respect to the polarizing film of Comparative Example 1. Moreover, it is also clear that infrared rays with a wavelength of 800 to 1600 nm are reflected satisfactorily. In addition, it can be seen that Example 2 reflects more infrared rays while having substantially the same reflectance of visible light as Example 1. Moreover, the polarizing film of Example 3 has a structure which reflects many large infrared rays compared with Comparative Example 1. Therefore, in the wavelength range of 750 to 800 nm in the vicinity of the infrared region, although reflection is increased compared to Comparative Example 1, in the visible region of wavelengths 600 to 750 nm or less, visible light reflection is smaller than in Comparative Example 1. From this, it can be seen that even when the infrared reflectance was set as a polarizing film of high infrared reflection exceeding 40%, the reflection of a majority of the red visible light wavelength region could be effectively suppressed.

(Cloudy under humid environment)

First, the haze before humidification was measured for the protective plate for image display devices of each Example and Comparative Example using a haze meter ("HGM-2DP", manufactured by Suga Test Instruments). Moreover, after mounting the protective plate for image display apparatuses of each Example and a comparative example on wet conditions of 60 degreeC and 95 %RH for 500 hours, the haze after humidification was measured. Table 1 shows these results.

(Exterior)

After the protective plate for image display device of each Example and Comparative Example was placed under wet conditions of 60 ° C. and 95% RH for 500 hours, the appearance of the protective plate for image display device by optical microscope observation (observation area: 300 cm 2 ) (specifically, , petechial corrosion of the infrared reflective layer) was evaluated.

The case where no appearance defect (corrosion) with a maximum length of 400 μm or more was not observed was evaluated as ◎, the case in which almost no appearance defect (corrosion) with a maximum length of 400 μm or more was hardly observed was evaluated as ○, and the appearance defect with a maximum length of 400 μm or more Cases in which defects were scattered were evaluated as ×. The results are shown in Table 1.

In addition, although the said invention was provided as embodiment of an illustration of this invention, this is only a mere illustration and should not be interpreted limitedly. Modifications of the present invention obvious to those skilled in the art are included in the claims described later.

The polarizing film, the protective plate for an image display device, and the retardation film of the present invention can be applied to various industrial products, and are preferably used, for example, for members for liquid crystal displays and the like.

1: Polarizing film
2: first transparent resin film
3: 1st adhesive layer
4: infrared reflective layer
5: 1st 1/4 wavelength layer
7: second transparent resin film
8: Polarizer
11: third transparent resin film
12: first inorganic oxide layer
13: metal layer
14: second inorganic oxide layer
15: retardation film
16: second adhesive layer
17: transparent protective plate
18: protective plate for image display device

Claims (13)

A first transparent resin film, an infrared reflective layer, and a polarizer are sequentially provided on one side in the thickness direction,
The infrared reflective layer includes a first inorganic oxide layer, a metal layer, and a second inorganic oxide layer in order,
The polarizing film, characterized in that the second inorganic oxide layer is semi-crystalline containing crystal grains in an amorphous film. According to claim 1,
A polarizing film further comprising a 1/4 wavelength layer between the infrared reflective layer and the polarizer. According to claim 1 or 2,
A second transparent resin film is further provided between the infrared reflective layer and the polarizer,
A polarizing film characterized in that the second transparent resin film has a thickness of 10 μm or more and 100 μm or less. According to claim 1 or 2,
The polarizing film characterized by further comprising a third transparent resin film on one side of the polarizer in the thickness direction. According to claim 4,
The polarizing film characterized in that the third transparent resin film is an ultraviolet ray absorbing layer. According to claim 1 or 2,
A polarizing film characterized by further comprising a first pressure-sensitive adhesive layer between the first transparent resin film and the infrared reflective layer. According to claim 1 or 2,
A polarizing film characterized in that the moisture permeability of the first transparent resin film is 5 g/m 2 24 h or more. According to claim 1 or 2,
The polarizing film characterized in that the metal layer is a silver layer or a silver alloy layer. According to claim 1,
The polarizing film characterized in that the first inorganic oxide layer and the second inorganic oxide layer contain an indium-based oxide. The polarizing film according to claim 1 or 2,
a second pressure-sensitive adhesive layer formed on one side of the polarizing film in the thickness direction;
A protective plate for an image display device characterized by comprising a transparent protective plate formed on one side of the second pressure-sensitive adhesive layer in the thickness direction. A first transparent resin film, an infrared reflective layer, and a 1/4 wavelength layer are sequentially provided on one side in the thickness direction,
The infrared reflective layer includes a first inorganic oxide layer, a metal layer, and a second inorganic oxide layer in order,
The second inorganic oxide layer is a phase difference film, characterized in that the semi-crystalline containing crystal grains in the amorphous film. According to claim 11,
Further comprising a second transparent resin film,
Retardation film, characterized in that the thickness of the second transparent resin film is 10 μm or more and 100 μm or less. According to claim 11 or 12,
Retardation film, characterized in that it further comprises a first pressure-sensitive adhesive layer between the first transparent resin film and the infrared reflective layer.

Images