TW202129377A - Optical laminate - Google Patents

Abstract

An object of the present invention is to provide an optical laminate (1) including a reflective polarizing plate (200) and an absorbent polarizing plate (100), which has both high polarization degree and high brightness. As a solution, the optical laminate (1) of the present invention includes a reflective polarizing plate (200) and an absorbent polarizing plate (100). When the luminosity factor correction polarization degree of the reflective polarizing plate (200) is Py1 [%] and the luminosity factor correction polarization degree of the absorbent polarizing plate (100) is Py2 [%], the optical laminate satisfies formula: Py1 ≥ 98.00, and formula: Py1 > Py2.

Description

Optical laminate

The present invention relates to an optical laminate.

Polarizers are widely used in image display devices such as liquid crystal display devices, and have been widely used in various mobile devices (small and medium-sized liquid crystal display devices) such as smart phones and tablet terminals in recent years. Polarizers are generally used for absorption-type polarizers with thermoplastic resin films on one or both sides of linear polarizers.

Japanese Patent Application Laid-Open No. 2017-211434 (Patent Document 1) discloses a laminated film including an adhesive layer, a polarizing film (equivalent to the above-mentioned absorption-type polarizing plate), and a reflective polarizing plate in this order.

[Prior Technical Literature]

[Patent Literature]

[Patent Document 1] JP 2017-211434 A

As described in Patent Document 1, in order to improve the brightness of the liquid crystal display device, a technique of arranging a reflective polarizer between the absorption polarizer on the backlight side and the backlight is known.

The present invention provides an optical laminate, which includes a reflective polarizer and an absorption polarizer, and the optical laminate has both high polarization and high brightness.

The present invention provides an optical laminate shown below.

[1] An optical laminate comprising a reflective polarizer and an absorptive polarizer, wherein the visual sensitivity correction polarization degree of the reflective polarizer is set to Py1[%], and the viewing angle of the absorptive polarizer When the sensitivity correction polarization is set to Py2[%], the following equations (1) and (2) are satisfied:

Py1≧98.00 (1)

Py1>Py2 (2).

[2] The optical laminate according to [1], wherein the single transmittance of the reflective polarizer is set to Ty1[%], and the visual sensitivity correction sheet of the absorptive polarizer is set to When the volume penetration rate is set to Ty2[%], the following formula (3) is more satisfied:

Ty1<Ty2 (3).

[3] The optical laminate according to [1] or [2], wherein when the visual sensitivity correction monomer transmittance of the absorption-type polarizing plate is set to Ty2[%], Ty2 is 44.5% or more.

[4] The optical laminate according to any one of [1] to [3], wherein the visual sensitivity correction polarization degree Py3 of the optical laminate is 99.85% or more.

[5] The optical laminate according to any one of [1] to [4], wherein the visual sensitivity correction monomer transmittance Ty3 of the optical laminate is 43.0% or more.

The present invention can provide an optical laminate including a reflective polarizer and an absorption polarizer, and the optical laminate has both high polarization and high brightness.

1,2,3: Optical laminate

5: Polarizer

10: The first protective film

15: The first adhesive layer

20: The second protective film

25: The second adhesive layer

30, 40: Adhesive layer

50: LCD unit

60: Backlight

100: Absorptive polarizer

200: reflective polarizer

201: The first brightness enhancement film

202: The second brightness enhancement film

Fig. 1 is a schematic cross-sectional view showing an example of the layer structure of an optical laminate.

Fig. 2 is a schematic cross-sectional view showing another example of the layer structure of the optical laminate.

Fig. 3 is a schematic cross-sectional view showing still another example of the layer structure of the optical laminate.

Fig. 4 is a schematic cross-sectional view showing an example of the layer structure of a liquid crystal display device.

Hereinafter, the optical laminate related to the present invention will be described in detail.

〔1〕The composition of the optical laminate

The optical laminate related to the present invention (hereinafter, also simply referred to as "optical laminate") includes a reflective polarizing plate and an absorptive polarizing plate.

Fig. 1 is a schematic cross-sectional view showing an example of the layer structure of the optical laminate. The optical laminate 1 shown in FIG. 1 includes a reflective polarizer 200 and an absorption polarizer 100 laminated on the reflective polarizer 200. In the optical laminate 1, the absorption-type polarizing plate 100 includes a polarizer 5 and a first protective film 10 laminated on one surface of the polarizer 5 with a first adhesive layer 15 interposed therebetween. The reflective polarizer 200 is laminated on the surface of the polarizer 5 opposite to the first protective film 10 with an adhesive (also called pressure sensitive adhesive) layer 30 interposed therebetween. The reflective polarizer 200 is separated from each other with adhesive Layer (not shown) or an adhesive layer (not shown) to laminate two brightness enhancement films (first brightness enhancement film 201 and second brightness enhancement film 202).

Fig. 2 is a schematic cross-sectional view showing another example of the layer structure of the optical laminate. The absorptive polarizer 100 constituting the optical laminate 2 shown in FIG. 2 also includes a polarizer 5 and a first protective film 10 laminated on one side of the polarizer 5 with a first adhesive layer 15 interposed therebetween. The reflective polarizer 200 constituting the optical layered body 2 is laminated on the outer surface of the first protective film 10 with the adhesive layer 30 interposed therebetween. The reflective polarizer 200 is a layer of two brightness enhancement films (the first brightness enhancement film 201 and the second brightness enhancement film 202) with an adhesive layer (not shown) or an adhesive layer (not shown) interposed between each other. .

Fig. 3 is a schematic cross-sectional view showing still another example of the layer structure of the optical laminate. The absorption type polarizing plate 100 in the optical laminate 3 shown in FIG. 3 includes a polarizer 5, a first protective film 10 laminated on one side of the polarizer 5 with a first adhesive layer 15 interposed therebetween, and The second protective film 20 is laminated on the other side of the polarizer 5 with the second adhesive layer 25 interposed therebetween. The reflective polarizer 200 is laminated on the absorptive polarizer 100 with the adhesive layer 30 interposed therebetween. The reflective polarizer 200 is a layer of two brightness enhancement films (the first brightness enhancement film 201 and the second brightness enhancement film 202) with an adhesive layer (not shown) or an adhesive layer (not shown) interposed between each other. .

As shown in FIGS. 1 to 3, the absorbing polarizer 100 and the reflective polarizer 200 are preferably laminated via an adhesive layer, or laminated via an adhesive layer. The absorbing polarizer 100 is preferably connected to the adhesive layer or the adhesive layer. The reflective polarizer 200 is preferably connected to the adhesive layer or the adhesive layer.

〔2〕Optical characteristics of reflective polarizers, absorptive polarizers and optical laminates

The reflective polarizer 200 and the absorptive polarizer 100 contained in the optical laminate satisfy the following equations (1) and (2) in terms of optical characteristics.

Py1≧98.00 (1)

Py1>Py2 (2)

In the formula, Py1 represents the visual sensitivity corrected polarization degree [%] of the reflective polarizer 200 (hereinafter, also referred to only as the "polarization degree Py1" of the reflective polarizer 200), and Py2 represents the visual sensitivity of the absorption polarizer 100 Sensitivity correction polarization degree [%] (hereinafter, also referred to only as "polarization degree Py2" of the absorption polarizer 100).

By satisfying the formula (1) and formula (2), an optical laminate with high polarization and high brightness can be provided. The inventor found that by setting the degree of polarization Py1 of the reflective polarizer 200 to 98.00% or more, and setting the degree of polarization Py1 to be relatively high with respect to the degree of polarization Py2 of the absorptive polarizer 100, an optical laminate can be realized. The high visual sensitivity of the body corrects the degree of polarization Py3 (hereinafter, also referred to only as "the degree of polarization Py3" of the optical laminate), and can realize the high brightness of the optical laminate.

From the viewpoint of both high polarization and high brightness, the polarization Py1 of the reflective polarizer 200 is preferably 98.10% or more, more preferably 98.20% or more, even more preferably 98.30% or more, and even more preferably 98.40 %above. From the point of view of both high polarization and high brightness, the polarization Py1 should be 98.50% or more, 98.70% or more, and 99.90% or more. The degree of polarization Py1 is below 100%, or below 99.98%, or below 99.96%, or below 99.94%.

From the viewpoint of achieving both high polarization and high brightness, it is also possible to increase the difference between the polarization Py1[%] and the polarization Py2[%]. From the above point of view, the difference is preferably in the following order: 0.5% or more, 1% or more, 2% or more, 3% or more, 4% or more, 5% or more (for example, 6% or more, 7% Above or above 8%). The difference is, for example, 20% or less, 18% or less, 15% or less, or 13% or less.

If the degree of polarization Py2 of the absorption polarizer 100 satisfies the above formula (2), there is no particular limitation. The absorbance P2 is usually 98% or less, and from the viewpoint of balancing high polarization and high brightness, it is preferably 96% or less, even better, 95% or less, even better, 92% or less, even better, 90% or less, and particularly good, 89% or less. The degree of polarization Py2 is usually 80% or more. From the viewpoint of taking into account both high degree of polarization and high brightness, it is preferably more than 82%, more preferably more than 85%.

From the viewpoint of achieving both high polarization and high brightness, the reflective polarizer 200 and the absorptive polarizer 100 contained in the optical laminate preferably satisfy the following formula (3).

Ty1<Ty2 (3)

In the formula, Ty1 represents the single transmittance [%] of the visual sensitivity correction of the reflective polarizer 200 (hereinafter, also referred to only as the "transmittance Ty1" of the reflective polarizer 200), and Ty2 represents the absorption polarizer The visual sensitivity of the plate 100 is corrected by the single transmittance [%] (hereinafter, only referred to as the "transmittance Ty2" of the absorption polarizer 100).

From the viewpoint of both high polarization and high brightness, the difference between the transmittance Ty2[%] and the transmittance Ty1[%] can be increased. From the above point of view, the difference is preferably 0.5% or more, more preferably 1% or more, still more preferably 2% or more, and still more preferably 2.5% or more. The difference is, for example, 10% or less, or 5% or less.

The transmittance Ty1 and the transmittance Ty2 can be selected from the range of 40% or more and 50% or less, for example. The penetration rate Ty1 and the penetration rate Ty2 are usually less than 50%. From the viewpoint of both high polarization and high brightness, the transmittance Ty2 is preferably 43% or more, more preferably 44.5% or more, even more preferably 46% or more, and even more preferably 47% or more. In addition, the transmittance Ty2 is preferably 49% or less, more preferably 48% or less, for example, 46% to 48%. Increasing the transmittance Ty2 further increases the degree of polarization Py3 of the optical laminate relative to the degree of polarization Py2 of the absorption polarizer 100 contained in the optical laminate, which is advantageous.

Optical multilayer system can express excellent polarization degree Py3. The degree of polarization Py3 is preferably 99.85% or more, and can be 99.86% or more, 99.87% or more, 99.90% or more, 99.92% or more, 99.95% or more, or 99.98% or more.

From the viewpoint of brightness enhancement, the visual sensitivity correction monomer transmittance Ty3 of the optical laminate (hereinafter, also simply referred to as the "transmittance Ty3" of the optical laminate) is preferably above 43.0%. The penetration rate Ty3 is less than 50%, usually less than 50%.

〔3〕Reflective polarizing plate

The reflective polarizer 200 is a polarization conversion element that separates the light of the backlight into penetrating polarized light and reflected polarized light or scattered light. The reflective polarizer allows the polarized light component parallel to the transmission axis to pass through while maintaining its original polarization state. When the reflective polarizer has the function of separating the light of the backlight into penetrating polarized light and reflected polarized light, the polarized light component parallel to the reflection axis maintains its original polarization state and reflects. The reflection axis is orthogonal to the penetration axis. When the reflective polarizer has the function of separating the backlight light into penetrating polarized light and scattered light, the polarized light component parallel to the scattering axis is reflected as scattered light. The scattering axis is orthogonal to the penetration axis.

Since the reflective polarizer 200 is arranged on the absorptive polarizer 100, the utilization efficiency of backlight light can be improved. Therefore, compared to the case where the reflective polarizer 200 is not used and only the absorptive polarizer 100 is used, it is Can improve the brightness of the liquid crystal display device.

As the reflective polarizer 200, commercially available products having the above-mentioned functions can be used.

The reflective polarizer 200 contained in the optical laminate may be, for example, one brightness enhancement film belonging to the polarization conversion element having the above-mentioned functions, or two or more of the brightness enhancement film, usually three or less. The best combination of 2 pieces. When two or more of the brightness enhancement films are laminated as the reflective polarizer 200, these brightness enhancement films may be laminated via an adhesive layer or an adhesive layer. When two or more of the above-mentioned brightness enhancement films are combined, they are laminated so that the penetration axes of the respective brightness enhancement films become parallel to each other. By combining two or more polarization conversion elements with the above-mentioned functions, the degree of polarization Py1 of the reflective polarizer 200 can be increased compared to a case where one polarization conversion element is formed.

Examples of the polarization conversion element having the above-mentioned function include an anisotropic reflective polarizer. Examples of the anisotropic reflective polarizer include an anisotropic multiple film that transmits linearly polarized light in one vibration direction and reflects linearly polarized light in the other vibration direction.

Regarding the degree of polarization Py1 and transmittance Ty1 of the above-mentioned reflective polarizer 200, when the reflective polarizer 200 is composed of a single brightness enhancement film that is a polarization conversion element with the above-mentioned functions, they respectively mean The degree of polarization and transmittance of the one piece of brightness enhancement film; when it is a laminate composed of two or more pieces of the brightness enhancement film having the above-mentioned function as a polarization conversion element, it means the degree of polarization of the laminate. And penetration rate. The degree of polarization and transmittance at this time include the degree of polarization and transmittance of the adhesive layer or the adhesive layer intervening between the brightness enhancement films.

The adhesive or adhesive system that forms the above-mentioned adhesive layer or adhesive layer can be those described later.

The above-mentioned adhesive layer and adhesive layer can be used, for example, not to affect the degree of polarization Py1 and transmittance Ty1 of the reflective polarizer 200, and the degree of polarization Py3 and transmittance Ty3 of the optical laminate, or substantially no effect. Influencer.

The thickness of the reflective polarizer 200 is not particularly limited. The thickness of the reflective polarizer 200 is, for example, 10 μm or more and 200 μm or less. From the viewpoint of thinning of optical laminates and liquid crystal display devices, it is preferably 10 μm or more and 100 μm or less, and more preferably 10 μm or more and 70 μm or less.

In the optical laminate, the reflective polarizer 200 is preferably laminated on the absorptive polarizer 100 such that the angle formed by the reflection axis and the absorption axis of the absorptive polarizer 100 becomes parallel or slightly parallel. The so-called parallel or slightly parallel means that the above-mentioned angle is specifically 0±5°. In terms of suppressing light leakage during black display and even improving the contrast of the liquid crystal display device, the above-mentioned angle is advantageous within the above-mentioned range.

When the reflective polarizer 200 is a laminate containing two or more films that are polarization conversion elements with the above-mentioned functions, the two or more films are preferably laminated so that their reflection axes are parallel or slightly parallel. . The so-called parallel or slightly parallel in this specification specifically means that the angle formed by the reflection axis thereof is 0±5°. In terms of suppressing light leakage during black display and even improving the contrast of the liquid crystal display device, it is advantageous for the angle to be within the above-mentioned range.

〔4〕Absorption type polarizing plate

The absorptive polarizer 100 is an optical element including a polarizer and a protective film attached to at least one side of the polarizer. The protective film can be attached to both sides of the polarizer. The so-called polarizer here is an absorption type linear polarizer with the following properties: it absorbs linearly polarized light having a vibration plane parallel to its absorption axis, and makes it perpendicular to the absorption axis (parallel to the transmission axis) The linearly polarized light of the vibrating surface penetrates.

The polarizer system may be formed by adsorbing or aligning dichroic dyes such as iodine on an oriented polyvinyl alcohol-based resin film, for example. The polarizer can be a single-layer polyvinyl alcohol resin film that allows dichroic pigments to be adsorbed orientated, or two or more layers of polyvinyl alcohol resin layers with adsorbed and oriented dichroic pigments on the base film The laminated film. Such a polarizer can be manufactured by various methods known in the art.

The above-mentioned polarizer can be manufactured, for example, by a method including the following steps: a step of uniaxially stretching a polyvinyl alcohol-based resin film; and dyeing the polyvinyl alcohol-based resin film with a dichroic dye to adsorb two The step of color pigment; the step of treating the polyvinyl alcohol resin film with the dichroic pigment adsorbed with the boric acid aqueous solution; and the step of washing with water after the treatment with the boric acid aqueous solution.

The degree of polarization Py2 and the transmittance Ty2 of the absorption polarizer 100 can be adjusted, for example, by adjusting the concentration of the dichroic pigment in the dyeing solution immersed in the polyvinyl alcohol resin film in the step of adsorbing the dichroic pigment. , The immersion time of the polyvinyl alcohol resin film, the temperature of the dyeing solution and other manufacturing conditions are controlled.

The thickness of the polarizer formed by adsorbing the oriented dichroic dye on a single-layer polyvinyl alcohol resin film is preferably 20 μm or less, more preferably 15 μm or less, and still more preferably 10 μm or less.

The polarizer may be a cured film formed by aligning a dichroic dye with a polymerizable liquid crystal compound and polymerizing the polymerizable liquid crystal compound. The polarizer is usually made by coating a composition containing a polymerizable liquid crystal compound and a dichroic dye on a base film composed of a thermoplastic resin film or the like, or an alignment layer provided on the base film, and then drying It is obtained by polymerizing and curing the polymerizable liquid crystal compound contained in the coating film by irradiation with active energy rays such as ultraviolet rays. The laminated system of the base film and the polarizer (cured film) obtained in this way can be used as the absorption-type polarizing plate 100.

The thickness of the base film for forming the above-mentioned cured film is not particularly limited. In general, from the viewpoint of workability such as strength and handling properties, the thickness of the base film is preferably 1 μm or more and 300 μm or less, more preferably 10 μm or more and 200 μm or less, and still more preferably 30 μm or more and 120 μm or less.

In the absorptive polarizer 100, the protective film to be attached to at least one side of the polarizer includes, for example, polyolefin resins such as polyethylene and polypropylene; cyclic polyolefin resins such as norbornene polymers; Polyester resins such as polyethylene terephthalate and polyethylene naphthalate; (meth)acrylic resins such as polymethyl (meth)acrylate; triacetyl cellulose, diacetyl cellulose Cellulose ester resins such as cellulose and cellulose acetate propionate; vinyl alcohol resins such as polyvinyl alcohol and polyvinyl acetate; polycarbonate resins; polystyrene resins; polyarylate resins; Polyether series resin; polyether series resin; polyamide series resin; polyimide series resin; polyetherketone series resin; polyphenylene sulfide series resin; polyphenylene oxide series resin, and the like A resin film composed of thermoplastic resins such as mixtures and copolymers.

Among the above-mentioned thermoplastic resins, it is preferable to use any one of a cyclic polyolefin resin, a polyester resin, a cellulose ester resin, and a (meth)acrylic resin, or a mixture thereof.

In addition, the so-called "(meth)acrylic acid" means "at least one of acrylic acid and methacrylic acid".

In the absorptive polarizer 100, when a protective film is attached to both sides of the polarizer, the protective film may be a film made of the same kind of resin, or a film made of a different kind of resin.

The protective film may be a protective film that also has optical functions such as a retardation film. For example: the above-mentioned film made of thermoplastic resin can be stretched (uniaxially stretched or biaxially stretched, etc.), or a liquid crystal layer is formed on the film, and the retardation film can be given an arbitrary retardation value. .

Any additives can be added to the protective film. Examples of the additive system include ultraviolet absorbers, antioxidants, smoothing agents, plasticizers, release agents, anti-coloring agents, flame retardants, nucleating agents, antistatic agents, pigments, and coloring agents.

From the viewpoint of thinning and durability of the optical laminate, the thickness of the protective film is preferably 2 μm or more and 300 μm or less, more preferably 5 μm or more and 200 μm or less, still more preferably 5 μm or more and 100 μm or less, and still more preferably 5μm or more and 50μm or less, particularly preferably 5μm or more and 30μm or less.

The refractive index of the protective film is, for example, 1.46 to 1.55.

The protective film system can be laminated on the polarizer via an adhesive layer, for example.

Examples of the adhesive system forming the adhesive layer include water-based adhesives, active energy ray-curable adhesives, and the like.

Examples of the water-based adhesive system include polyvinyl alcohol-based resin aqueous solutions, water-based two-component urethane-based emulsion adhesives, and the like.

Active energy ray curable adhesives are adhesives that are cured by irradiating active energy rays such as ultraviolet rays. Examples include: those containing polymerizable compounds and photopolymerizable initiators, those containing photoreactive resins, and those containing binder resins. And photo-reactive cross-linking agents, etc. Examples of the above-mentioned polymerizable compound systems include photopolymerization of photocurable epoxy monomers, photocurable (meth)acrylic monomers, and photocurable urethane monomers. Monomers, or oligomers derived from these monomers, etc. Examples of the photopolymerization initiator system include those that include those that generate active species such as neutral radicals, anionic radicals, and cationic radicals by irradiating active energy rays such as ultraviolet rays.

Before bonding the polarizer with the adhesive and the protective film, you can perform surface activation treatment on the bonding surface of the polarizer and/or the bonding surface of the protective film as needed, such as plasma treatment, corona treatment , Ultraviolet radiation treatment, flame (Flame) treatment, saponification treatment, etc.

(5) Adhesive layer

The adhesive system that can be used to form the adhesive layer 30 by stacking the absorbing polarizer 100 and the reflective polarizer 200 includes, for example, (meth)acrylic resin, styrene resin, silicone resin, etc. As the base polymer, an adhesive composition containing a crosslinking agent such as an isocyanate compound, an epoxy compound, and an aziridine compound is added.

The thickness of the adhesive layer 30 is, for example, 1 to 40 μm, preferably 3 to 25 μm.

The refractive index of the adhesive layer 30 is, for example, 1.46 to 1.52. When a protective film is attached to one or both sides of the polarizer, and the adhesive layer 30 is attached to the protective film, the refractive index of the adhesive layer 30 can be the same as that of the protective film, or it can be the same as that of the protective film. The refractive index is different. When the refractive indexes of the two are different, the difference is, for example, more than 0.00 and 0.06 or less, and may be 0.05 or less. The refractive index of the adhesive layer 30 may be greater than the refractive index of the protective film, or may be smaller than the refractive index of the protective film.

In order to laminate the absorbing polarizer 100 and the reflective polarizer 200, an adhesive layer can also be used instead of the adhesive layer. Examples of the adhesive system forming the adhesive layer include the above-mentioned water-based adhesives, active energy ray-curable adhesives, and the like.

〔6〕Other elements that can be added to the optical laminate arbitrarily

Other elements that can be arbitrarily added to the optical laminate include, for example: a protective film laminated on one or both sides of the optical laminate; an adhesive layer laminated on one or both sides of the optical laminate; and an adhesive layer laminated on the adhesive layer Surface separation film (release film); polarizers and reflective polarizers other than optical functional layers laminated on one or both sides of the optical laminate.

[7] Liquid crystal display device

4 is a schematic cross-sectional view showing an example of the layer structure of the liquid crystal display device. The liquid crystal display device shown in FIG. 4 includes a backlight 60, an optical laminate 1 and a liquid crystal cell 50 in this order. Fig. 4 uses the optical laminate 1 shown in Fig. 1 as an example of the optical laminate.

The optical laminate system is arranged so that the absorption-type polarizer 100 is on the side of the liquid crystal cell 50, that is, it is arranged so that the reflective polarizer 200 is on the side of the backlight 60. The optical laminated system can be laminated on the liquid crystal cell 50 via the adhesive layer 40.

The driving method of the liquid crystal cell can be any conventionally known method. The driving method of the liquid crystal cell is preferably in-plane switching (IPS) and vertical orientation (VA) modes.

In the liquid crystal display device including the optical laminate of the present invention, since the optical laminate has high polarization and high brightness, excellent visibility and brightness can be obtained.

[Example]

Hereinafter, examples and comparative examples are shown to describe the present invention more specifically. In addition, the present invention is not limited to these examples.

<Manufacturing Example 1: Manufacturing of Absorptive Polarizer A>

A 30μm thick polyvinyl alcohol film (degree of saponification: 99.9 mol% or more, average degree of polymerization of polyvinyl alcohol: about 2400) was immersed in pure water at 30°C for 30 seconds, and then immersed in iodine at 28°C: 0.45 mM, potassium iodide: 2% by mass aqueous solution for 100 seconds for dyeing. Dyed polyvinyl alcohol The film was immersed in an aqueous solution of potassium iodide: 12% by mass and boric acid: 4% by mass at 55°C for 70 seconds to perform crosslinking treatment. After the crosslinked polyvinyl alcohol film was washed with pure water at 5°C for 3 seconds, it was dried at 60°C for 150 seconds to obtain a linear polarizer (absorption type) with a thickness of 12 μm. From immersion in pure water to drying, it was processed while stretching, and the total stretching ratio was about 5.6 times.

After bonding a triacetyl cellulose (TAC) film (thickness 20 μm, refractive index 1.48, manufactured by Konica Minolta Co., Ltd.) on one side of the obtained linear polarizer via a polyvinyl alcohol-based adhesive, It was dried at °C for 5 minutes to obtain an absorption-type polarizing plate A composed of a linear polarizer/adhesive layer/TAC film.

<Manufacturing Example 2: Manufacturing of Absorptive Polarizer B>

Except that the iodine concentration of the aqueous solution used for the dyeing treatment was set to 0.40 mM, in the same manner as in Production Example 1, a linear polarizer (absorption type) having a thickness of 12 μm was obtained. The total extension ratio is about 5.6 times.

After bonding an unstretched cyclic polyolefin resin (COP) film (thickness 23μm, refractive index 1.53, manufactured by ZEON Co., Ltd.) on one side of the obtained linear polarizer through a polyvinyl alcohol-based adhesive , Dried at 80°C for 5 minutes to obtain an absorption polarizer B composed of a linear polarizer/adhesive layer/COP film.

<Manufacturing Example 3: Manufacturing of Absorptive Polarizing Plate C>

A polyvinyl alcohol film (degree of saponification: 99.9 mol% or more, average degree of polymerization of polyvinyl alcohol: about 2400) with a thickness of 20 μm was dry-stretched to be approximately 4 times. The dry stretched polyvinyl alcohol film was immersed in pure water at 40°C for 40 seconds, and then immersed in an aqueous solution of iodine: 1.3 mM and potassium iodide: 5.7% by mass at 28°C for 30 seconds to perform dyeing treatment. The dyed polyvinyl alcohol film was immersed in an aqueous solution of potassium iodide: 11% by mass and boric acid: 6.0% by mass at 70°C for 120 seconds to perform crosslinking treatment. After the cross-linked polyvinyl alcohol film was washed with 8°C pure water for 15 seconds, it was dried at 70°C for 60 seconds to obtain Linear polarizer (absorption type) with a thickness of 8μm. The polyvinyl alcohol film is processed in a state that maintains a tight state after dry stretching. The total extension ratio is about 4 times.

A TAC film (thickness 20μm, refractive index 1.48, manufactured by Konica Minolta Co., Ltd.) was laminated on one side of the obtained linear polarizer via a polyvinyl alcohol-based adhesive, and then dried at 65°C for 5 minutes to obtain a linear polarizer. Absorptive polarizer C composed of polarizer/adhesive layer/TAC film.

<Example 1: Production of optical laminate 1>

On the "APF-V3" film (thickness 26μm) made by 3M, the same "APF-V3" film was laminated via a (meth)acrylic adhesive layer (thickness 5μm, refractive index 1.48). A reflective polarizer I with a layer of "APF-V3" film/(meth)acrylic adhesive layer/"APF-V3" film. On the "APF-V3" film surface of one of the reflective polarizers I, a (meth)acrylic adhesive layer (thickness 5μm) is interposed and the absorptive polarizer A is placed on its linear polarizer side ( It is bonded to the surface of the linear polarizer where the TAC film is bonded is the opposite side) to obtain a TAC film/adhesive layer/linear polarizer/(meth)acrylic adhesive layer/reflective polarizer I The optical laminate 1 formed by the layers. In the optical laminate 1, the reflection axis of the two "APF-V3" films and the absorption axis of the linear polarizer are parallel.

<Example 2: Production of optical laminate 2>

Except that the absorptive polarizer B is used instead of the absorptive polarizer A, the rest is the same as in Example 1 to obtain a COP film/adhesive layer/linear polarizer/(meth)acrylic adhesive layer/reflective type Optical laminate 2 composed of layers of polarizing plate I. In the optical laminate 2, the reflection axis of the two "APF-V3" films and the absorption axis of the linear polarizer are parallel.

<Comparative example 1: Production of optical laminate 3>

On the surface of the absorption-type polarizer C on the linear polarizer side (the surface on the opposite side of the linear polarizer where the TAC film is attached is the opposite side), the above 3M is attached via a (meth)acrylic adhesive layer (thickness 5μm) Company system With the "APF-V3" film, an optical laminate 3 having a layer configuration of TAC film/adhesive layer/linear polarizer/(meth)acrylic adhesive layer/reflective polarizer II was obtained. The reflective polarizer II is composed of one sheet of "APF-V3" film. In the optical laminate 3, the reflection axis of the "APF-V3" film and the absorption axis of the linear polarizer are parallel.

<Comparative example 2: Production of optical laminate 4>

Except that the absorptive polarizer B is used instead of the absorptive polarizer C, the rest is the same as in Comparative Example 1, to obtain a COP film/adhesive layer/linear polarizer/(meth)acrylic adhesive layer/reflective type Optical laminate 4 composed of layers of polarizing plate II. The reflective polarizer II is composed of one sheet of "APF-V3" film. In the optical laminate 4, the reflection axis of the "APF-V3" film and the absorption axis of the linear polarizer are parallel.

<Comparative example 3: Production of optical laminate 5>

Except that the absorption-type polarizer A is used instead of the absorption-type polarizer C, the rest is the same as in Comparative Example 1, to obtain a TAC film/adhesive layer/linear polarizer/(meth)acrylic adhesive layer/reflective type Optical laminate 5 composed of layers of polarizing plate II. The reflective polarizer II is composed of one sheet of "APF-V3" film. In the optical laminate 5, the reflection axis of the "APF-V3" film and the absorption axis of the linear polarizer are parallel.

[Measurement]

(1) Measurement of the single transmittance Ty of the visual sensitivity correction and the polarization degree Py of the visual sensitivity correction

(1-1) Measurement of the single transmittance Ty1 and the polarization correction Py1 of the visual sensitivity correction of the reflective polarizer

On one side of the "APF-V3" film that is one of the reflective polarizers (in the production of optical laminates, the surface where the absorbing polarizer is attached), or on the reflective polarizer "APF-V3 "One side of the membrane (in In the production of the optical laminate, the surface of the absorbing polarizer is bonded, and the alkali-free glass plate (trade name "EAGLE XG" manufactured by CORNING, thickness 0.7mm) is bonded via a (meth)acrylic adhesive layer. The measurement sample is obtained. The measurement sample was set on a spectrophotometer with an integrating sphere ("V7100" manufactured by JASCO Corporation, 2 degree field of view; C light source), and Ty1 and Py1 were measured. The measurement sample is installed so that incident light enters from the side opposite to the alkali-free glass plate. The measurement results are shown in Table 1.

In addition, the monomer transmittance and polarization are defined by the following formulas:

Monomer transmittance (λ)=0.5×(Tp(λ)+Tc(λ))

Polarization (λ)=100×(Tp(λ)-Tc(λ))/(Tp(λ)+Tc(λ))

. Tp(λ) is the transmittance (%) when measured by the relationship between incident wavelength λnm linearly polarized light and parallel polarized light, Tc(λ) is measured by the relationship between incident wavelength λnm linearly polarized light and orthogonal polarized light Penetration rate (%).

Visual sensitivity correction monomer transmittance Ty and visual sensitivity correction polarization degree Py, for each wavelength of the monomer transmittance (λ) and polarization (λ) by JIS Z 8701 2 degree field of view (C light source) Those who have undergone visual sensitivity correction. Ty and Py are measured in a wavelength range of 380 to 780 nm with a scale of 5 nm.

(1-2) Measurement of the single transmittance Ty2 of the optical sensitivity correction and the polarization Py2 of the optical sensitivity correction of the absorption polarizer

In addition to being on the side of the linear polarizer of the absorbing polarizer, an alkali-free glass plate (trade name "EAGLE XG" manufactured by CORNING, thickness 0.7mm) is bonded via a (meth)acrylic adhesive layer. Except that the measurement sample was obtained, Ty2 and Py2 were measured in the same manner as in (1-1) above. The measurement sample is installed in such a way that incident light enters from the side of the alkali-free glass. The measurement results are shown in Table 1.

(1-3) Measurement of the monomer transmittance Ty3 and the polarization correction Py3 of the visual sensitivity correction of the optical laminate

Except for the TAC film surface or the COP film surface of the optical laminate, the alkali-free glass plate is laminated with a (meth)acrylic adhesive layer (trade name "EAGLE XG" manufactured by CORNING, thickness 0.7mm) Except for obtaining the measurement sample, the rest is the same as the above (1-1), and Ty3 and Py3 are measured. The measurement sample is installed so that incident light enters from the side opposite to the alkali-free glass plate. The measurement results are shown in Table 1.

Regarding the measurement of (1-1) to (1-3) above, the haze system of the adhesive layer and (meth)acrylic adhesive layer contained in the absorption polarizer, reflective polarizer, and optical laminate It is colorless and transparent to a negligible degree, and light absorption is also negligible. The adhesive layer and the (meth)acrylic adhesive layer are not for absorption polarizers, reflective polarizers, and optical laminates. The measured value of the penetration rate caused the influence.

(2) Measurement of brightness of optical laminate

The same measurement sample as the measurement sample prepared in (1-3) above was prepared. The measurement sample was placed on the backlight (brightness 12270 cd/m ² ) with the absorption-type polarizing plate side facing upward. The light around the measurement sample is shielded in such a way that the light of the backlight does not leak. A spectroradiometer (trade name "SR-UL1R" manufactured by TOPCON Co., Ltd.) was installed directly above the measurement sample, and the brightness was measured at a measurement angle of 1° in a dark room environment.

The measurement results are shown in Table 1. Table 1 shows relative values when the brightness displayed by the optical laminate 3 of Comparative Example 1 is set to 100.

[Table 1]

<Example 3: Production of optical laminate 6>

Except that the absorption-type polarizer A obtained in the same manner as in Example 1 was used as the absorption-type polarizer, and the visual sensitivity correction monomer transmittance Ty1 was 45.3%, and the visual sensitivity correction polarization degree Py1 was 99.94%. One brightness enhancement film (reflective polarizer III) (International Publication No. 2018/163009) was used to replace the reflective polarizer I, and the rest was the same as in Example 1, to obtain a TAC film/adhesive layer/linear polarized light Optical laminate 6 composed of sheet/(meth)acrylic adhesive layer/reflective polarizer III. In this optical laminate 6, the reflection axis of the reflective polarizer III and the absorption axis of the linear polarizer are parallel to each other.

The visual sensitivity correction monomer transmittance Ty3, visual sensitivity correction polarization degree Py3, and brightness of the optical laminate 6 were measured in the same manner as above. The result was that the visual sensitivity correction monomer transmittance Ty3 was 43.8%, and the visual sensitivity corrected polarization. The degree Py3 is 99.98%, and the brightness (relative value) is 103.

<Example 4: Production of optical laminate 7>

Except that the absorption polarizer B obtained in the same manner as in Example 2 was used as the absorption polarizer, the rest was the same as in Example 3 to obtain a COP film/adhesive layer/linear polarizer/(甲Base) Optical laminate 7 composed of an acrylic adhesive layer/reflective polarizer III layer.

In the same manner as above, the visual sensitivity correction monomer transmittance Ty3, visual sensitivity correction polarization degree Py3, and brightness of the optical laminate 7 were measured. The result was that the visual sensitivity correction monomer transmittance Ty3 was 44.3%, and the visual sensitivity was corrected. The degree of polarization Py3 is 99.98%, and the brightness (relative value) is 105.

1: Optical laminate

5: Polarizer

10: The first protective film

15: The first adhesive layer

30: Adhesive layer

100: Absorptive polarizer

200: reflective polarizer

201: The first brightness enhancement film

202: The second brightness enhancement film

Claims (5)

An optical laminated body comprising a reflective polarizer and an absorption polarizer, wherein the visibility correction polarization of the reflective polarizer is set to Py1[%], and the visibility correction polarization of the absorption polarizer is When the degree is set to Py2[%], the system satisfies the following equations (1) and (2): Py1≧98.00 (1) Py1>Py2 (2). The optical laminate according to claim 1, wherein the optical sensitivity correction monomer transmittance of the reflective polarizer is set to Ty1[%], and the optical sensitivity correction monomer transmittance of the absorptive polarizer is set to When the rate is set to Ty2[%], the system more satisfies the following formula (3): Ty1<Ty2 (3). The optical laminate according to claim 1 or 2, wherein when the visual sensitivity correction monomer transmittance of the absorption-type polarizing plate is set to Ty2[%], Ty2 is 44.5% or more. The optical layered body according to any one of claims 1 to 3, wherein the visual sensitivity correction polarization degree Py3 of the optical layered body is 99.85% or more. The optical laminate according to any one of claims 1 to 4, wherein the visual sensitivity correction monomer transmittance Ty3 of the optical laminate is 43.0% or more.

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