WO2018139638A1

WO2018139638A1 - Display device

Info

Publication number: WO2018139638A1
Application number: PCT/JP2018/002695
Authority: WO
Inventors: 弘昌橋本; 拓也三浦; 村上　俊秀
Original assignee: 日本ゼオン株式会社
Priority date: 2017-01-30
Filing date: 2018-01-29
Publication date: 2018-08-02
Also published as: JPWO2018139638A1; KR20190108564A; CN110050210A; TW201827870A; KR102638928B1; JP6977737B2; TWI746782B

Abstract

Provided is a display device comprising, in this order, a polarizer protection film, a polarizer, a retardation film, and a display element, wherein the polarizer protection film includes a substrate containing a laser absorbing agent and being capable of serving as a λ/4 plate, and the in-plane retardation Re (550) of the retardation film at a wavelength of 550 nm is 90-150 nm.

Description

Display device

The present invention relates to a display device.

Display devices are installed in various electronic devices ranging from mobile devices to large-sized TVs. Conventionally, a liquid crystal display device has been generally used as the display device. However, in recent years, electronic devices using organic electroluminescence display devices (hereinafter sometimes referred to as “organic EL display devices” as a display device) as a display device have been increasing mainly in mobile devices such as notebook computers and mobile phones. It is in.

From the viewpoint of improving the design and portability of mobile devices, it is required to make the entire mobile device modules thinner and lighter. In addition, televisions are required to be large. Further, in a display device, it is generally required to make the display screen highly delicate. Therefore, an optical film and a polarizing plate used in these display devices are also required to be thinned, widened, and improved in quality. A touch panel is often used for the display window of the display device. Among several types of touch panels, the multi-touch function that enlarges or reduces the image by hitting, flipping, and picking the screen with your fingertips, as well as excellent visibility and durability. The popularity of touch panels is high. In order to meet such demands, various studies have been conducted as shown in Patent Documents 1 to 14.

International Publication No. 2016/31776 JP 2014-191006 A JP 2010-76181 A Japanese Patent No. 582155 International Publication No. 2016/200956 International Publication No. 2014/185000 Japanese Patent Laid-Open No. 10-10523 Japanese Patent Laid-Open No. 1-204092 JP-A-3-174512 JP 2009-122454 A JP 2005-181615 A Japanese Patent Laid-Open No. 2015-031753 Japanese Patent Laid-Open No. 05-100114 Japanese Patent Laid-Open No. 10-68816

Generally, in a manufacturing process of a display device, a polarizing plate is bonded to a glass substrate of a display element via an adhesive or an adhesive. A polarizing plate is usually manufactured with a configuration in which a polarizer protective film is laminated on both sides of a polarizer in which a dichroic dye is adsorbed and oriented on a polyvinyl alcohol-based resin film. Typical examples of the polarizer protective film include a cyclic olefin film and a triacetylcellulose film. Moreover, a polarizer protective film is normally laminated | stacked on both surfaces of a polarizer through the liquid adhesive or adhesive agent containing water or an organic solvent.

It is desirable that the polarizing plate is bonded so as to reach the periphery of the glass substrate of the display element. However, the polarizer protective film may undergo dimensional changes due to the influence of the humidity and temperature of the external environment and the pressure-sensitive adhesive or adhesive used. As a countermeasure against this dimensional change, after pasting a polarizing plate having a size larger than the periphery of the display element in advance, the polarizing plate protruding from the edge of the glass substrate of the display element is cut without damaging the glass substrate. Things have been done.

Also, it is required to freely cut the polarizing plate into a desired shape without damaging the glass substrate according to the screen size of the display device.

Furthermore, in recent years, particularly in the manufacturing process of display devices, a “roll-to-panel manufacturing method” in which a roll-shaped polarizing plate and a panel including a display element are directly bonded has been adopted. The roll-shaped polarizing plate manufactured by such a roll-to-panel manufacturing method is cut into a desired dimension.

Also, as the screen size increases, there is a demand to increase the width of the film. In response to this requirement, a wide stretched film is produced by fixing the width direction end of the roll-shaped raw film produced by the melt casting method and the solution casting method with a clip and transversely stretching. Has been. However, since both ends of the stretched film have clip marks, it is usually required to cut the unnecessary portions.

On the other hand, the touch panel is generally provided with a translucent cover panel that is disposed in the display window and functions as a dielectric. And the capacitive film sensor is normally adhere | attached on the back surface of this cover panel through the adhesion layer or the contact bonding layer. This film sensor is provided on the surface of the base material, the first electrode portion provided on the surface on one side (observer side) of the base material, and the other side (display device side) of the base material. A second electrode portion. In such a film sensor, a desired portion of the surface on one side and the surface on the other side of the substrate is cut to form a conductive wiring having conductivity.

Examples of the method for cutting out the polarizer protective film and the polarizing plate into a desired shape include a mechanical cutting method using a knife and a laser cutting method using laser light. However, when mechanical cutting is performed, invisible scratches and non-uniform residual stress may be caused. Under such circumstances, in recent years, it is required to adopt a laser cutting method.

Furthermore, along with the demands for thinner, lighter, more flexible, higher quality and higher definition display devices, the polarizing plates used there are also required to be thinner, lighter, more flexible and higher performance. ing. However, these requirements are difficult to achieve simply by thinning the components of the polarizing plate such as the polarizer, the pressure-sensitive adhesive layer, the adhesive layer, and the polarizer protective film. Specifically, when the polarizing plate is made thinner, the polarizer is easily broken in the stretching direction, the polarizer and the polarizer protective film are deteriorated by the adhesive or the adhesive, or the polarizing plate is curved. At the time of reworking the polarizing plate, there was a tendency that the handleability was inferior, or the tear strength was low and the peelability was poor. Under such circumstances, there is a demand for a polarizing plate that is thin and lightweight but has durability superior to the current situation.

However, depending on the type of material, sufficient durability may not be obtained depending on the usage environment (humidity, temperature, ultraviolet rays, etc.) and usage form (adhesive used for bonding, bending use, etc.). For example, when the usage environment or usage pattern is severe, or the usage environment or usage pattern changes, the influence of the heat resistance, moisture resistance, light resistance, solvent resistance, diffraction resistance, tear resistance, etc. Properties such as property and dimensional stability may not always be sufficient.

Moreover, it may be difficult to cut | disconnect a polarizer protective film with a laser beam. If it is forcibly cut with a laser beam, cutting residue may be mixed into the polarizing plate. Moreover, the rising of the cut surface of the polarizer protective film occurred, and the polarizer protective film layer floated in the polarizing plate thus produced, resulting in a decrease in moisture resistance. Therefore, there was a problem with the workability of the polarizer protective film.
The present invention has been invented in view of the above-described problems, and includes a polarizer protective film that can be cut by a laser beam, and a display device that includes a polarizing plate that is excellent in durability against use environment and use form. The purpose is to provide.

As a result of intensive studies to solve the above problems, the present inventor has found that the polarizer protective film can be cut with a laser beam by providing the polarizer protective film with a substrate containing a laser absorbent. The present invention has been completed.
That is, the present invention includes the following.

[1] A display device comprising a polarizer protective film, a polarizer, a retardation film and a display element in this order,
The polarizer protective film contains a laser absorber and a substrate that can function as a λ / 4 plate,
The display device, wherein the retardation film has an in-plane retardation Re (550) at a wavelength of 550 nm of 90 nm to 150 nm.
[2] The base material has a first base material layer having an in-plane retardation Re (550) of 10 nm or less at a wavelength of 550 nm, and a second base material having an in-plane retardation Re (550) at a wavelength of 550 nm of 90 nm to 150 nm. A base material layer, and a conductive layer formed on at least one surface of the first base material layer,
[1] The display device according to [1], wherein the laser absorbent is contained in one or both of the first base material layer and the second base material layer.
[3] The base material is formed on at least one surface of the first base material layer that can function as a λ / 4 plate, the second base material layer that can function as a λ / 2 plate, and the first base material layer. And can function as a broadband λ / 4 plate,
[1] The display device according to [1], wherein the laser absorbent is contained in one or both of the first base material layer and the second base material layer.
[4] The display device according to [3], wherein the second base material layer is formed of a cured product of a liquid crystal composition containing a liquid crystal compound.
[5] One or both of the first base material layer and the second base material layer are
A first outer layer;
A second outer layer;
The display device according to any one of [2] to [4], including an intermediate layer provided between the first outer layer and the second outer layer.
[6] The display device according to [5], wherein the intermediate layer includes an ultraviolet absorber.
[7] The first outer layer is formed by a first outer resin having a glass transition temperature Tg _O1,
The second outer layer is formed with a second outer resin having a glass transition temperature Tg _O2,
The intermediate layer is formed of an intermediate resin having a glass transition temperature Tg _C ;
The glass transition temperature Tg _O1 of the first outer resin is lower than the glass transition temperature Tg _{C of the} intermediate resin,
The glass transition temperature Tg _O2 of the second outer resin, the lower the glass transition temperature Tg _C of the intermediate resin, [5] or [6] The display device according.
[8] The difference Tg _C −Tg _O1 between the glass transition temperature Tg _O1 of the first outer resin and the glass transition temperature Tg _C of the intermediate resin is 30 ° C. or more.
[7] The display device according to [7], wherein a difference Tg _C -Tg _O2 between the glass transition temperature Tg _O2 of the second outer resin and the glass transition temperature Tg _C of the intermediate resin is 30 ° C or higher.
[9] The display device according to any one of [2] to [8], wherein the thickness of one or both of the first base material layer and the second base material layer is 10 μm to 60 μm.
[10] The display device according to any one of [1] to [9], wherein a slow axis of the substrate intersects a transmission axis of the polarizer.
[11] The display device according to [10], wherein the crossing angle between the slow axis of the substrate and the transmission axis of the polarizer is 45 ° ± 5 °.
[12] The display device according to any one of [1] to [11], wherein the base material includes a crystalline polymer.
[13] The display device according to any one of [1] to [12], wherein the base material and the retardation film each include an alicyclic structure-containing polymer.
[14] The display device according to any one of [1] to [13], wherein the base material and the retardation film each include a stretched film.
[15] The retardation film is formed of a cured product of a liquid crystal composition containing a liquid crystal compound,
The in-plane retardation Re (450) of the retardation film at a wavelength of 450 nm and the in-plane retardation Re (550) of the retardation film at a wavelength of 550 nm are Re (450) / Re (550) <1.0. The display device according to any one of [1] to [12], wherein:
[16] The display device according to any one of [1] to [15], wherein the display element is a liquid crystal cell.
[17] The display device according to any one of [1] to [15], wherein the display element is an organic electroluminescence element.

According to the present invention, it is possible to provide a display device that includes a polarizer protective film that can be cut by a laser beam, and a polarizing plate that is excellent in durability for use environment and use form.

FIG. 1 is a cross-sectional view schematically showing a display device according to an embodiment of the present invention. FIG. 2 is a cross-sectional view schematically showing an example of a resin layer that can be included in the substrate. FIG. 3 is a cross-sectional view schematically showing a base material as an example. FIG. 4 is a cross-sectional view schematically showing a base material as an example. FIG. 5 is a cross-sectional view schematically showing an example of a liquid crystal display device as a display device according to an embodiment of the present invention. FIG. 6 is a cross-sectional view schematically showing an example of an organic EL display device as a display device according to another embodiment of the present invention. FIG. 7 is a cross-sectional view schematically showing an example of an organic EL display device as a display device according to another embodiment of the present invention. FIG. 8 is a cross-sectional view schematically showing an example of an organic EL display device as a display device according to another embodiment of the present invention. FIG. 9 is a cross-sectional view schematically showing an example of an organic EL display device as a display device according to another embodiment of the present invention.

Hereinafter, the present invention will be described in detail with reference to embodiments and examples. However, the present invention is not limited to the following embodiments and exemplifications, and can be implemented with any modifications without departing from the scope of the claims of the present invention and the equivalents thereof.

In the following description, “ultraviolet light” indicates light having a wavelength of 10 nm to 400 nm unless otherwise specified.

In the following description, the “long” shape refers to a shape having a length of 5 times or more, preferably 10 times or more, and specifically a roll. It refers to the shape of a film having such a length that it can be wound up and stored or transported. The upper limit of the length of the long shape is not particularly limited, and can be, for example, 100,000 times or less with respect to the width.

In the following description, the in-plane retardation Re of the film and the layer is a value represented by Re = (nx−ny) × d unless otherwise specified. Further, the retardation Rth in the thickness direction of the film and layer is a value represented by Rth = {(nx + ny) / 2−nz} × d unless otherwise specified. Here, nx represents a refractive index in a direction (in-plane direction) perpendicular to the thickness direction of the film and the layer and giving the maximum refractive index. ny represents the refractive index in the in-plane direction of the film and the layer and in a direction perpendicular to the nx direction. nz represents the refractive index in the thickness direction of the film and the layer. d represents the thickness of a film and a layer. The measurement wavelength is 550 nm unless otherwise specified.

In the following description, unless otherwise specified, the front direction of a surface means the normal direction of the surface, and specifically refers to the direction of the polar angle 0 ° and the azimuth angle 0 ° of the surface.

In the following description, unless otherwise specified, the “forward wavelength dispersion characteristic” means that the in-plane retardations Re (450) and Re (550) at wavelengths of 450 nm and 550 nm have a relationship of Re (450)> Re (550). Satisfying.

In the following description, unless otherwise specified, the “reverse wavelength dispersion characteristic” means that the in-plane retardations Re (450) and Re (550) at wavelengths of 450 nm and 550 nm have a relationship of Re (450) <Re (550). Satisfying.

In the following description, unless otherwise indicated, the slow axis of the film and layer represents the slow axis in the plane of the film and layer.

In the following description, the angle formed by the optical axis (polarization absorption axis, polarization transmission axis, slow axis, etc.) of each film or layer in a member having a plurality of films or layers is the above film or layer unless otherwise specified. Represents the angle when viewed from the thickness direction.

In the following description, unless otherwise specified, the term “(meth) acryloyl group” includes acryloyl group, methacryloyl group, and combinations thereof.

In the following description, a resin having a positive intrinsic birefringence value means a resin in which the refractive index in the stretching direction is larger than the refractive index in the direction perpendicular thereto unless otherwise specified. Further, the resin having a negative intrinsic birefringence value means a resin having a refractive index in the stretching direction that is smaller than a refractive index in a direction orthogonal thereto unless otherwise specified. The intrinsic birefringence value can be calculated from the dielectric constant distribution.

In the following description, “polarizing plate”, “λ / 2 plate” and “λ / 4 plate” are not limited to rigid members, unless otherwise specified, such as a resin film. The member which has is also included.

[1. Overview]
FIG. 1 is a cross-sectional view schematically showing a display device 10 according to an embodiment of the present invention.
As shown in FIG. 1, the display apparatus 10 which concerns on one Embodiment of this invention is equipped with the polarizer protective film 110, the polarizer 120, the phase difference film 130, and the display element 140 in this order. Among these, the part which consists of the polarizer protective film 110 and the polarizer 120 functions as a polarizing plate.

The polarizer protective film 110 includes a substrate 111 that can absorb laser light. The base material 111 absorbs the laser light in the portion irradiated with the laser light, and the material of the base material 111 in the portion can be sublimated. In addition, when the polarizer protective film 110 includes an optional element (not shown) other than the base material 111, when the laser light is irradiated, the optional element is heated by the material of the sublimated base material 111 to be melted or sublimated. Can result. Therefore, the polarizer protective film 110 can be easily cut by the laser light. When the polarizer protective film 110 is cut in a state where it is bonded to the polarizer 120 and the retardation film 130, the polarizer protective film is usually generated by heat generated by the substrate 111 absorbing laser light. Not only 110 but also the polarizer 120 and the retardation film 130 can be easily cut.

As described above, the display device 10 can be manufactured through the step of cutting the polarizer protective film 110 using laser light. According to the cutting | disconnection of the polarizer protective film 110 by a laser beam, generation | occurrence | production of a cutting waste can be suppressed or a cut surface can be made smooth. Thereby, in the display apparatus 10 provided with the polarizer protective film 110, it is possible to improve display quality.

In order to evaluate the ease of cutting of the polarizer protective film 110 by laser light, the cut surface is observed. The cut surface can be evaluated by the following evaluation method.
The polarizer protective film 110 and the polarizer 120 are removed from the display device as an integrated laminate without separating them. This laminated body is bonded to a glass plate (for example, thickness 0.7 mm) through an adhesive. Then, a laser beam is irradiated from the polarizer protective film side. Thus, the said cut surface can be evaluated by observing the cut surface of a polarizer protective film under a microscope in the state irradiated with the laser beam.

[2. Polarizer protective film]
In order to enable absorption of laser light, the substrate included in the polarizer protective film contains a laser absorber. Moreover, the polarizer protective film may contain arbitrary layers combining with a base material.

[2.1. Base material]
As the substrate, a film that can be cut by a laser beam can be used. Examples of the film that can be cut by laser light include 1) a film containing a polymer having a high average absorbance of laser light, and 2) a film containing a polymer having a low average absorbance of laser light and a laser absorber. Is mentioned. However, in general, a polymer having a high average absorbance of laser light has a polarity and tends to be highly hygroscopic. Therefore, as a base material, the film containing a polymer with a low average light absorbency of a laser beam and a laser absorber is preferable.

The absorbance of laser light can be measured using the “ATR method”. The “ATR method” is a method of obtaining an absorption spectrum on the surface of the measurement target by irradiating the measurement target with laser light having an arbitrary wavelength and measuring light totally reflected on the surface of the measurement target. . Within the wavelength range of the irradiated laser beam, the absorbance of light having an arbitrary wavelength is measured using the ATR method, and the average absorbance can be obtained by calculating the average value of the obtained absorbances.

[2.1.1. Laser absorber contained in substrate]
As the laser absorber, a compound capable of absorbing laser light used for cutting can be used. In general, infrared laser light is often used industrially as laser light. Here, the infrared laser beam refers to a laser beam having a wavelength in the infrared range of 760 nm or more and less than 1 mm. Therefore, it is preferable to use a compound that can absorb infrared laser light as the laser absorber. In particular, as infrared laser light, CO ₂ laser light having a wavelength in the range of 9 μm to 11 μm is widely used because it has few cracks and chips on the cut surface and good workability. There are _two types of CO ₂ laser light, one with a wavelength of 10.6 μm and one with a wavelength of 9.4 μm. In cutting processing of a polarizer protective film and a polarizing plate, one with a wavelength of 9.4 μm should be used. Recommended. For example, in the case of cutting using a laser wavelength of 9.4 μm as compared with the case of cutting using a laser wavelength of 10.6 μm, the melt projects or melts and deforms on the cut end face of the polarizing plate. Since this can be suppressed, the cut end face becomes smooth. Therefore, it is preferable to use a compound capable of absorbing laser light having a wavelength in the range of 9 μm to 11 μm as the laser absorber. In particular, it is preferable to use a compound having absorption maximums at 9.4 μm and 10.6 μm.

Preferable laser absorbers include ester compounds. The ester compound is usually a polar compound, and can effectively absorb laser light having a wavelength in the range of 9 μm to 11 μm. Examples of the ester compound include a phosphoric acid ester compound, a carboxylic acid ester compound, a phthalic acid ester compound, and an adipic acid ester compound. Among these, a carboxylic acid ester compound is preferable from the viewpoint of particularly efficiently absorbing CO ₂ laser light.

Among the ester compounds described above, those containing an aromatic ring in the molecule are preferable, and those having an ester bond bonded to the aromatic ring are particularly preferable. Such an ester compound can absorb laser light more efficiently. Therefore, among the ester compounds described above, aromatic carboxylic acid esters are preferable, and benzoic acid esters such as diethylene glycol dibenzoate and pentaerythritol tetrabenzoate are particularly preferable because of excellent laser light absorption efficiency.
Examples of such ester compounds include those described in International Publication No. 2016/31776.

Furthermore, the laser absorber is preferably one that can function as a plasticizer. In general, plasticizers can easily penetrate between polymer molecules in the resin. In particular, when a polar laser absorber is mixed with a base material containing a polar polymer, it can be well dispersed in the resin without forming a sea-island structure. Therefore, when the layer contained in the base material is formed of the resin, it is possible to suppress the local absorption of the laser light, and thus it is possible to improve the ease of cutting as the whole base material. Generally, when a polar substance and a non-polar substance are mixed, they are difficult to mix with each other, and thus haze may occur in the entire substrate.

Laser absorbers such as ester compounds may be used alone or in any combination of two or more.

The molecular weight of the laser absorber is preferably 300 or more, more preferably 400 or more, particularly preferably 500 or more, preferably 2200 or less, more preferably 1800 or less, and particularly preferably 1400 or less. By setting the molecular weight of the laser absorbent to be equal to or higher than the lower limit of the above range, bleeding out of the laser absorbent can be suppressed. In addition, by making the laser absorbent less than the upper limit, the laser absorbent can be made to function easily as a plasticizer, and the movement of the laser absorbent molecules can be accelerated after heat is applied, so that the polarizer protective film can be cut. Can be made easier.

The melting point of the laser absorber is preferably 20 ° C. or higher, more preferably 60 ° C. or higher, particularly preferably 100 ° C. or higher, preferably 180 ° C. or lower, more preferably 150 ° C. or lower, particularly preferably 120 ° C. or lower. . By setting the melting point of the laser absorbent to be equal to or higher than the lower limit of the above range, bleeding out of the laser absorbent can be suppressed. In addition, by making the laser absorbent less than the upper limit, the laser absorbent can be made to function easily as a plasticizer, and the movement of the laser absorbent molecules can be accelerated after heat is applied, so that the polarizer protective film can be cut. Can be made easier.

The laser absorber may be contained uniformly in the thickness direction of the substrate. For example, when the base material is a film having a single layer structure including only one layer, it is preferable that the base material uniformly contains a laser absorber. Moreover, when the base material is a film having a multilayer structure including a plurality of layers, all the layers included in the base material may contain a laser absorber.
Further, the laser absorbent may be unevenly distributed in the thickness direction of the base material, and thus may be contained only in a part of the base material. For example, when the base material is a film having a multilayer structure, only a part of the layers included in the base material may contain a laser absorber.

The content of the laser absorbent in the substrate can be arbitrarily set as long as the polarizer protective film can be cut with a laser beam. Therefore, it is preferable to set appropriately the content rate of the laser absorber of the layer containing a laser absorber among the layers contained in a base material in the range which can be cut | disconnected by the laser beam of a polarizer protective film. In particular, the content of the laser absorbent in the substrate is preferably set depending on whether the polymer contained in the substrate is nonpolar or polar.

Specifically, when the polymer contained in the substrate is nonpolar, the content of the laser absorber in the layer containing the laser absorber is preferably 0.1 wt% or more, more preferably 1 wt% or more, The amount is particularly preferably 2% by weight or more, preferably 10% by weight or less, more preferably 9% by weight or less, and particularly preferably 8% by weight or less. By setting the content of the laser absorbent to be equal to or higher than the lower limit of the above range, the base material can be imparted with a property capable of efficiently absorbing laser light without impairing the original optical characteristics and mechanical characteristics of the base material. Moreover, since the haze of a base material can be made low by setting it as an upper limit or less, transparency of a polarizer protective film can be made favorable. Furthermore, when the polarizer protective film is cut by laser light, it is possible to prevent the cross section of the cut polarizer protective film from becoming locally high temperature and causing large deformation due to heat melting.

When the polymer contained in the substrate is polar, the content of the laser absorber in the layer containing the laser absorber is mixed more than when the polymer contained in the substrate is nonpolar, although it depends on the mixing conditions. be able to. The property of efficiently absorbing laser light can be imparted to the substrate by the laser absorbent. Further, from the viewpoint of making it difficult to impair the original characteristics of the base material (for example, in-plane retardation and dimensional stability), it is desirable not to add too much laser absorber.

The dimensional stability of the film can be evaluated by the following evaluation method.
The film cut into 150 mm × 150 mm is used as a test piece, and the dimensions of the long film in the MD direction (flow direction) and the TD direction (width direction) are measured. Thereafter, the film is placed horizontally on a talc bath in a gear oven maintained at 150 ° C., and the deformation amounts in the MD direction and the TD direction after heating for 30 minutes are measured. The dimensional stability can be evaluated by this deformation amount.

[2.1.2. Polymer that can be contained in substrate]
The substrate usually contains a polymer in combination with the laser absorber described above. Specifically, the substrate is usually a film provided with one or more resin layers containing a polymer, and part or all of the resin layers contain a laser absorber. Under the present circumstances, it is preferable that a base material contains the polymer which has crystallinity from a viewpoint of improving solvent resistance, diffraction resistance, and tear strength. In particular, when a crystalline polymer film and an amorphous polymer film are cut with a laser beam having the same wavelength and the same output, the crystalline polymer film is curled. It is hard to produce. Therefore, from this viewpoint, a polymer having crystallinity is preferable. Here, the polymer having crystallinity refers to a polymer having a melting point Mp. The polymer having the melting point Mp means a polymer whose melting point Mp can be observed with a differential scanning calorimeter (DSC).

The base material preferably contains a nonpolar alicyclic structure-containing polymer as a polymer from the viewpoint of low hygroscopicity and low water vapor permeability. Therefore, the base material is preferably a film having a single layer structure or a multilayer structure including a resin layer containing an alicyclic structure-containing polymer.

The alicyclic structure-containing polymer is a polymer having an alicyclic structure in the repeating unit. Since the alicyclic structure-containing polymer is excellent in mechanical strength, the impact strength of the polarizer protective film can be effectively increased. Moreover, since the alicyclic structure-containing polymer has low hygroscopicity, the water vapor transmission rate of the polarizer protective film can be effectively reduced. Furthermore, the alicyclic structure-containing polymer is usually excellent in transparency, dimensional stability and lightness.

Examples of the alicyclic structure-containing polymer include a polymer that can be obtained by a polymerization reaction using a cyclic olefin as a monomer, or a hydrogenated product thereof. Moreover, as said alicyclic structure containing polymer, both the polymer which contains alicyclic structure in a principal chain, and the polymer which contains alicyclic structure in a side chain can be used. Examples of the alicyclic structure include a cycloalkane structure and a cycloalkene structure, and a cycloalkane structure is preferable from the viewpoint of thermal stability.

The number of carbon atoms contained in one alicyclic structure is preferably 4 or more, more preferably 5 or more, more preferably 6 or more, preferably 30 or less, more preferably 20 or less, Particularly preferred is 15 or less. When the number of carbon atoms contained in one alicyclic structure is within the above range, mechanical strength, heat resistance, and moldability are highly balanced.

The ratio of the repeating unit having an alicyclic structure in the alicyclic structure-containing polymer is preferably 30% by weight or more, more preferably 50% by weight or more, still more preferably 70% by weight or more, and particularly preferably 90% by weight. That's it. Heat resistance can be improved by increasing the ratio of the repeating unit having an alicyclic structure as described above.
In the alicyclic structure-containing polymer, the remainder other than the structural unit having an alicyclic structure is not particularly limited and may be appropriately selected according to the purpose of use.

As the alicyclic structure-containing polymer, either a polymer having crystallinity or a polymer having no crystallinity may be used, or both may be used in combination. By using an alicyclic structure-containing polymer having crystallinity, the impact strength, solvent resistance, diffraction resistance, and tear strength of the polarizer protective film can be particularly increased. Moreover, the manufacturing cost of a polarizer protective film can be lowered | hung by using the alicyclic structure containing polymer which does not have crystallinity.

Examples of the alicyclic structure-containing polymer having crystallinity include the following polymer (α) to polymer (δ). Among these, the polymer (β) is preferable as the alicyclic structure-containing polymer having crystallinity because a polarizer protective film having excellent heat resistance can be easily obtained.
Polymer (α): A ring-opening polymer of a cyclic olefin monomer having crystallinity.
Polymer (β): A hydrogenated product of polymer (α) having crystallinity.
Polymer (γ): An addition polymer of a cyclic olefin monomer having crystallinity.
Polymer (δ): a hydrogenated product of polymer (γ), etc., having crystallinity.

Specifically, the alicyclic structure-containing polymer having crystallinity is a ring-opening polymer of dicyclopentadiene having crystallinity, and a hydrogenated product of a ring-opening polymer of dicyclopentadiene. It is more preferable to have crystallinity, and a hydrogenated product of a ring-opening polymer of dicyclopentadiene that has crystallinity is particularly preferable. Here, the ring-opening polymer of dicyclopentadiene means that the proportion of structural units derived from dicyclopentadiene relative to all structural units is usually 50% by weight or more, preferably 70% by weight or more, more preferably 90% by weight or more, More preferably, it refers to a polymer of 100% by weight.

The polymer having an alicyclic structure having crystallinity may not be crystallized before the polarizer protective film is produced. However, after the polarizer protective film is manufactured, the alicyclic structure-containing polymer having crystallinity contained in the base material can usually have a high crystallinity by being crystallized. . The specific crystallinity range can be appropriately selected according to the desired performance, but is preferably 10% or more, more preferably 15% or more. By setting the crystallinity of the alicyclic structure-containing polymer contained in the base material to be not less than the lower limit of the above range, high heat resistance and solvent resistance can be imparted to the polarizer protective film. Crystallinity can be measured by X-ray diffraction.

The heat resistance of the polarizer protective film can be evaluated by the heat resistant temperature. The heat-resistant temperature of the polarizer protective film is usually 160 ° C. or higher, preferably 180 ° C. or higher, more preferably 200 ° C. or higher. The higher the heat-resistant temperature, the better, so there is no upper limit on the heat-resistant temperature, but in the case of a crystalline polymer, the melting point is Tm or less.

The heat resistant temperature of the film can be evaluated by the following evaluation method.
In a state where no tension is applied to the film as the sample, the film is allowed to stand for 10 minutes in an atmosphere at a certain temperature Tx. Thereafter, the surface state of the film is confirmed visually. When unevenness is not confirmed in the shape of the surface of the film, it can be seen that the heat resistant temperature of the film is equal to or higher than the temperature Tx.

The solvent resistance of the film can be evaluated by the following evaluation method.
A film (50 mm × 10 mm sample) as a sample is cut out and 1 ml of a predetermined solvent is applied. One minute after application, the solvent resistance can be evaluated by observing the appearance change of the film.

As the solvent having resistance to the polarizer protective film, a solvent used for an adhesive or an adhesive can be used. Specific examples of the solvent include aliphatic hydrocarbons such as hexane, cyclohexane and octane; aromatic hydrocarbons such as toluene and xylene; alcohols such as ethanol, 1-propanol, isopropanol, 1-butanol and cyclohexanol; methyl ethyl ketone And ketones such as methyl isobutyl ketone and cyclohexanone; esters such as ethyl acetate, butyl acetate and isobutyl acetate; monocyclics such as limonene;

Generally, when manufacturing a polarizing plate, a polarizer protective film and a polarizer are bonded by the adhesive or adhesive containing a solvent. At this time, if the polarizer protective film does not have resistance to the solvent, the quality of the polarizing plate is deteriorated, and as a result, the display quality of the display device may be lowered. However, if the alicyclic structure-containing polymer having crystallinity is used, a polarizer protective film having excellent solvent resistance can be obtained, and the above-described deterioration in quality can be suppressed.
Whether or not the polarizing plate obtained by laminating the polarizer protective film and the polarizer through an adhesive or adhesive has deteriorated the quality, has two polarizing plates placed on a polarizing microscope. When one of the polarizing plates is rotated, it can be evaluated by the clarity of black and white and the presence or absence of light leakage.

The melting point Mp of the alicyclic structure-containing polymer having crystallinity is preferably 200 ° C. or higher, more preferably 230 ° C. or higher, and preferably 290 ° C. or lower. By using an alicyclic structure-containing polymer having crystallinity having such a melting point Mp, a polarizer protective film having a further excellent balance between moldability and heat resistance can be obtained.

An alicyclic structure-containing polymer having crystallinity is excellent in folding resistance. Therefore, the polarizer protective film is preferably excellent in folding resistance. Specifically, the folding resistance of the polarizer protective film can be expressed by folding resistance. The folding resistance of the polarizer protective film provided with the substrate containing the alicyclic structure-containing polymer having crystallinity is usually 2000 times or more, preferably 2200 times or more, more preferably 2400 times or more. Since the higher folding resistance is more preferable, the upper limit of folding resistance is not limited, but the folding resistance is normally 100000 times or less.

The folding resistance can be measured by the following method by an MIT folding resistance test according to JISP8115 “Paper and paperboard—Folding strength test method—MIT testing machine method”.
A test piece having a width of 15 mm ± 0.1 mm and a length of about 110 mm is cut out from the film as a sample. At this time, the test piece is prepared so that the direction in which the film is stretched more strongly is parallel to the side of about 110 mm of the test piece. Then, using a MIT folding resistance tester (“No. 307” manufactured by Yasuda Seiki Seisakusho), the load is 9.8 N, the curvature of the bent portion is 0.38 ± 0.02 mm, the bending angle is 135 ° ± 2 °, and the bending speed is Under the condition of 175 times / minute, the test piece is bent so that a fold appears in the width direction of the test piece. This bending is continued, and the number of reciprocal bendings until the test piece breaks is measured.

The alicyclic structure-containing polymer having crystallinity as described above can be produced, for example, by the method described in International Publication No. 2016/066873.

On the other hand, the alicyclic structure-containing polymer having no crystallinity includes, for example, (1) a norbornene polymer, (2) a monocyclic olefin polymer, (3) a cyclic conjugated diene polymer, and (4) vinyl. Examples thereof include alicyclic hydrocarbon polymers and hydrogenated products thereof. Among these, a norbornene polymer and this hydrogenated product are more preferable from the viewpoint of transparency and moldability.

Examples of norbornene polymers include, for example, ring-opening polymers of norbornene monomers, ring-opening copolymers of norbornene monomers with other monomers capable of ring-opening copolymerization, and hydrogenated products thereof; addition polymers of norbornene monomers; Examples include addition copolymers with other monomers copolymerizable with norbornene monomers. Among these, a ring-opening polymer hydrogenated product of norbornene monomer is particularly preferable from the viewpoint of transparency.
The above alicyclic structure-containing polymer is selected from, for example, polymers disclosed in JP-A No. 2002-321302.

As a resin containing an alicyclic structure-containing polymer having no crystallinity, various products are commercially available. Among them, those having desired characteristics can be appropriately selected and used. Examples of such commercial products are “ZEONOR” (manufactured by ZEON CORPORATION), “ARTON” (manufactured by JSR Corporation), “Apel” (manufactured by Mitsui Chemicals), “TOPAS” (manufactured by Polyplastics Co., Ltd.). ) Product group.

Among the above-mentioned polymers, from the viewpoint of low hygroscopicity and low water vapor permeability, the polymer is preferably nonpolar, and the polymer alone has a low average absorbance of laser light. Thus, when a polymer having a low average absorbance of laser light is used, the dimensional stability due to low hygroscopicity and the effect obtained by combining the laser absorbent can be used particularly effectively. Examples of the polymer having a low average absorbance of laser light include “ZEONOR” manufactured by Nippon Zeon Co., Ltd. The average absorbance of the cyclic olefin film comprising “ZEONOR” measured at a wavelength of 9.2 μm to 10.8 μm was 0.05.

As the polymer, one type may be used alone, or two or more types may be used in combination at any ratio.

The glass transition temperature Tg of the polymer is preferably 80 ° C. or higher, more preferably 85 ° C. or higher, still more preferably 100 ° C. or higher, preferably 250 ° C. or lower, more preferably 170 ° C. or lower. A polymer having a glass transition temperature in such a range is not easily deformed or stressed when used at high temperatures, and has excellent durability.

The weight average molecular weight (Mw) of the polymer is preferably 1,000 or more, more preferably 2,000 or more, still more preferably 10,000 or more, particularly preferably 25,000 or more, preferably 1,000,000. 000 or less, more preferably 500,000 or less, still more preferably 100,000 or less, particularly preferably 80,000 or less, particularly preferably 50,000 or less. A polymer having such a weight average molecular weight has an excellent balance between moldability and heat resistance.

The molecular weight distribution (Mw / Mn) of the polymer is preferably 1.0 or more, more preferably 1.2 or more, particularly preferably 1.5 or more, preferably 10 or less, more preferably 4.0 or less, More preferably, it is 3.5 or less. Here, Mn represents a number average molecular weight. A polymer having such a molecular weight distribution is excellent in moldability.

The aforementioned weight average molecular weight (Mw) and number average molecular weight (Mn) can be measured as polyisoprene or polystyrene equivalent weight average molecular weight by gel permeation chromatography using cyclohexane as a solvent. However, when the sample does not dissolve in cyclohexane, toluene may be used as a solvent for gel permeation chromatography.

The polymer content in the substrate can be arbitrarily set according to the characteristics required of the polarizer protective film. Therefore, it is preferable to set appropriately the content rate of the said polymer in the layer containing a polymer among the layers contained in a base material according to the characteristic calculated | required by a polarizer protective film. Specifically, the content of the polymer in the polymer-containing layer is preferably 50% by weight or more, more preferably 70% by weight or more, further preferably 80% by weight or more, and particularly preferably 90% by weight. That's it.

[2.1.3. Resin layer that can be contained in substrate]
FIG. 2 is a cross-sectional view schematically showing an example of a resin layer that can be included in the substrate. As shown in FIG. 2, the resin layer 200 included in the base material preferably has a first outer layer 210, a second outer layer 220, and the first outer layer 210 and the second outer layer 220. And an intermediate layer 230 provided. The resin layer 200 may include any layer other than the first outer layer 210, the intermediate layer 230, and the second outer layer 220 as necessary. However, from the viewpoint of reducing the thickness, the resin layer 200 may include any layer. A layer having a three-layer structure not provided is preferable. In such a resin layer 200, normally, the first outer layer 210 and the intermediate layer 230 are in direct contact with no other layers in between, and the intermediate layer 230 and the second outer layer 220 are in between. Directly touching without intervening other layers.

As shown in FIG. 2, when the resin layer 200 including the first outer layer 210, the second outer layer 220, and the intermediate layer 230 includes a laser absorber, this laser absorber is usually included in the intermediate layer 230. Since the laser absorber contained in the intermediate layer 230 is prevented from moving by the first outer layer 210 and the second outer layer 220, the resin layer 200 can suppress bleed-out of the laser absorber.

The intermediate layer 230 is usually formed of a resin containing a polymer. Hereinafter, the resin forming the intermediate layer 230 is appropriately referred to as “intermediate resin”. As the polymer contained in the intermediate resin, it is preferable to use a thermoplastic polymer because the resin layer 200 is easily manufactured. As such a polymer, an alicyclic structure-containing polymer is preferable because of excellent mechanical properties, heat resistance, transparency, low hygroscopicity, dimensional stability, and lightness. Moreover, a polymer may be used individually by 1 type and may be used combining two or more types by arbitrary ratios.
The content of the polymer in the intermediate layer 230 is preferably 80.0% by weight or more, more preferably 82.0% by weight or more, particularly preferably 85.0% by weight or more, preferably 97.0% by weight or less. More preferably, it is 96.0% by weight or less, particularly preferably 95.0% by weight or less.

In addition, the intermediate layer 230 may include a laser absorber as described above. The amount of the laser absorbent in the intermediate layer 230 can be appropriately set from the range described above as the range of the content of the laser absorbent in the layer containing the laser absorbent among the layers contained in the substrate. Specifically, the amount of the laser absorber in the intermediate layer 230 is preferably 0.1% by weight or more, particularly preferably 1.0% by weight or more, preferably 10.0% by weight or less, and particularly preferably 8.0%. % By weight or less.

The intermediate layer 230 can further include an optional component in combination with the polymer and the laser absorber. As an arbitrary component, an ultraviolet absorber is mentioned, for example. Since the intermediate layer 230 containing the ultraviolet absorber can prevent the transmission of ultraviolet rays, it is possible to suppress deterioration of the members included in the display device due to the ultraviolet rays. Therefore, coloring of the polarizer by ultraviolet rays contained in external light can be suppressed, and the lifetime of the display element can be increased by suppressing ultraviolet rays from the backlight. Further, when the intermediate layer 230 includes an ultraviolet absorber, it is possible to suppress the bleed-out of the ultraviolet absorber, so that the concentration of the ultraviolet absorber in the intermediate layer 230 can be increased or the type of the ultraviolet absorber can be selected. You can increase the width. Therefore, even if the thickness of the resin layer 200 is thin, it is possible to increase the ability to suppress ultraviolet light transmission.

Furthermore, by combining a laser absorber and an ultraviolet absorber, it is possible to suppress changes in characteristics such as in-plane retardation and cut-out dimensions of the resin, and to impart a property capable of efficiently absorbing laser light to the substrate. In addition, changes in the physical properties (in-plane retardation, dimensional change, internal haze, etc.) of the substrate can be suppressed. Furthermore, film thickness unevenness can be reduced in the film forming process. In particular, when a polymer having crystallinity is combined with a laser absorber and an ultraviolet absorber, effects such as suppression of the change in physical properties can be obtained remarkably. In general, even when a nonpolar polymer (for example, an alicyclic structure-containing polymer) having a low average absorbance of laser light is mixed with a polar compound (for example, an ester compound), dispersibility becomes insufficient, It was the technical recognition of those skilled in the art that there is a tendency for the physical property change to occur easily. Therefore, the above action is unexpected from the conventional technical common sense. The reason why such an effect can be obtained by using a combination of a laser absorber and an ultraviolet absorber is not well understood, but an appropriate laser absorber and an ultraviolet absorber are like a plasticizer in the intermediate layer 230. It is thought that this has an advantageous effect on the film forming process.

The total amount of the laser absorber and the ultraviolet absorber in the intermediate layer 230 is preferably 8.0% by weight or more, particularly preferably 10.0% by weight or more, preferably 20.0% by weight or less, particularly preferably 16.0. % By weight or less. By keeping the total amount of laser absorber and ultraviolet absorber within the above range, it is possible to suppress changes in physical properties such as retardation of the resin, less leakage from the die during compound production, and suppression of fish eye generation and resin burning. can do.

As the ultraviolet absorber, a compound that can absorb ultraviolet rays can be used. Usually, an organic compound is used as such an ultraviolet absorber. Hereinafter, an ultraviolet absorber as an organic compound may be referred to as an “organic ultraviolet absorber”. By using an organic ultraviolet absorber, it is usually possible to increase the light transmittance at a visible wavelength of the base material or to reduce the haze of the base material. Therefore, the display performance of the display device can be improved.

Examples of organic UV absorbers include triazine UV absorbers, benzophenone UV absorbers, benzotriazole UV absorbers, acrylonitrile UV absorbers, salicylate UV absorbers, cyanoacrylate UV absorbers, and azomethine UV absorbers. Examples thereof include an absorbent, an indole ultraviolet absorber, a naphthalimide ultraviolet absorber, and a phthalocyanine ultraviolet absorber.

As the triazine-based ultraviolet absorber, for example, a compound having a 1,3,5-triazine ring is preferable. Specific examples of triazine-based ultraviolet absorbers include 2- (4,6-diphenyl-1,3,5-triazin-2-yl) -5-[(hexyl) oxy] -phenol, 2,4-bis And (2-hydroxy-4-butoxyphenyl) -6- (2,4-dibutoxyphenyl) -1,3,5-triazine. Examples of such commercially available triazine ultraviolet absorbers include “Tinuvin 1577” manufactured by Ciba Specialty Chemicals, “LA-F70” and “LA-46” manufactured by ADEKA.

Examples of the benzotriazole ultraviolet absorber include 2,2′-methylenebis [4- (1,1,3,3-tetramethylbutyl) -6- (2H-benzotriazol-2-yl) phenol], 2 -(3,5-di-tert-butyl-2-hydroxyphenyl) -5-chlorobenzotriazole, 2- (2H-benzotriazol-2-yl) -p-cresol, 2- (2H-benzotriazole-2 -Yl) -4,6-bis (1-methyl-1-phenylethyl) phenol, 2-benzotriazol-2-yl-4,6-di-tert-butylphenol, 2- [5-chloro (2H)- Benzotriazol-2-yl] -4-methyl-6- (tert-butyl) phenol, 2- (2H-benzotriazol-2-yl) -4,6-di- ert-Butylphenol, 2- (2H-benzotriazol-2-yl) -4- (1,1,3,3-tetramethylbutyl) phenol, 2- (2H-benzotriazol-2-yl) -4-methyl -6- (3,4,5,6-tetrahydrophthalimidylmethyl) phenol, methyl 3- (3- (2H-benzotriazol-2-yl) -5-tert-butyl-4-hydroxyphenyl) propionate / Examples include the reaction product of polyethylene glycol 300, 2- (2H-benzotriazol-2-yl) -6- (linear and side chain dodecyl) -4-methylphenol, and the like. Examples of commercially available products of such triazole ultraviolet absorbers include “ADEKA STAB LA-31” manufactured by ADEKA and “TINUVIN 326” manufactured by Ciba Specialty Chemicals.

Examples of the azomethine-based ultraviolet absorber include materials described in Japanese Patent No. 336697, and examples of commercially available products include “BONASORB UA-3701” manufactured by Orient Chemical Co., Ltd.

Examples of indole ultraviolet absorbers include materials described in Japanese Patent No. 2846091. Examples of commercially available products include “BONASORB UA-3911” and “BONASORB UA-3912” manufactured by Orient Chemical Co., Ltd. Etc.

Examples of the phthalocyanine-based ultraviolet absorber include materials described in Japanese Patent Nos. 4403257 and 3286905, and examples of commercially available products include “FDB001” and “FDB002” manufactured by Yamada Chemical Industries, Ltd. Or the like.

Particularly preferred UV absorbers are “LA-F70” manufactured by ASDEKA, a triazine UV absorber; Oriental Chemical Industry “UA-3701”, an azomethine UV absorber; and a benzotriazole UV absorber. Examples thereof include “Tinuvin 326” manufactured by BASF and “LA-31” manufactured by ADEKA. Since these are particularly excellent in the ability to absorb ultraviolet rays, the resin layer 200 having a high ultraviolet blocking ability can be obtained even if the amount is small.

As the ultraviolet absorber, one type may be used alone, or two or more types may be used in combination at any ratio.

The amount of the UV absorber in the intermediate layer 230 is preferably 3% by weight or more, more preferably 4% by weight or more, particularly preferably 5% by weight or more, preferably 20% by weight or less, more preferably 18% by weight or less. Particularly preferably, it is 16% by weight or less. When the amount of the ultraviolet absorber is not less than the lower limit of the above range, the resin layer 200 can effectively suppress the transmission of ultraviolet rays. Moreover, it is easy to make the light transmittance in the visible wavelength of the resin layer 200 high because the quantity of an ultraviolet-ray is below the upper limit of the said range. Moreover, since the gelation of the resin by the ultraviolet absorber can be suppressed at the time of manufacturing the resin layer 200, it is easy to suppress the generation of fish eyes in the resin layer 200. Here, the fish eye refers to a foreign substance that can be generated inside the layer.

Further, other examples of optional components include, for example, colorants such as pigments and dyes; plasticizers; fluorescent brighteners; dispersants; lubricants; thermal stabilizers; light stabilizers; A compounding agent such as a surfactant. One of these may be used alone, or two or more of these may be used in combination at any ratio.

The glass transition temperature Tg _C of the intermediate resin is preferably 100 ° C. or higher, more preferably 120 ° C. or higher, particularly preferably 140 ° C. or higher, preferably 180 ° C. or lower, more preferably 170 ° C. or lower, particularly preferably 165 ° C. It is as follows. The glass transition temperature Tg _C of the intermediate resin falls within the above range, so that changes in physical properties such as retardation of the intermediate layer 230 can be suppressed, or the film thickness can be stabilized during the production of the intermediate layer 230 to reduce film thickness unevenness. Can be made possible.

The thickness _{T 230} of the intermediate layer 230, the ratio _T 230 _{/ T 200} thickness _{T 230} of the intermediate layer 230 to the thickness _{T 200} of the resin layer 200 is preferably set to fall in a predetermined range. Specifically, the thickness ratio T ₂₃₀ / T ₂₀₀ is preferably 1/4 or more, more preferably 2/4 or more, preferably 80/82 or less, more preferably 79/82 or less, and particularly preferably. Is 78/82 or less. When the thickness ratio is equal to or greater than the lower limit, the resin layer 200 can effectively absorb laser light. Moreover, when the intermediate layer 230 contains an ultraviolet absorber, the transmission of ultraviolet rays can be effectively suppressed. Further, since the first outer layer 210 and the second outer layer 220 can be thickened when the thickness ratio is equal to or less than the upper limit value, the bleeding out of the laser absorber and the ultraviolet absorber can be stably suppressed, or the resin The layer 200 can be easily manufactured.

The thickness of each layer in the resin layer including a plurality of layers can be measured by the following method. A resin layer is embedded with an epoxy resin to prepare a sample piece. This sample piece is sliced to a thickness of 0.05 μm using a microtome. Then, the thickness of each layer contained in the resin layer can be measured by observing the cross section that appears by slicing using a microscope.

The first outer layer 210 is usually formed of a resin containing a polymer. Hereinafter, the resin forming the first outer layer 210 is appropriately referred to as “first outer resin”. The first outer resin preferably has a lower content of the laser absorbent than the intermediate resin contained in the intermediate layer 230, and more preferably does not contain the laser absorbent. Further, the first outer resin preferably has a lower UV absorber content than the intermediate resin contained in the intermediate layer 230, and more preferably does not contain the UV absorber.

As the polymer contained in the first outer resin, the same polymer as that contained in the intermediate resin is preferably used. Thereby, it is easy to increase the adhesive strength between the intermediate layer 230 and the first outer layer 210, or to suppress the reflection of light at the interface between the intermediate layer 230 and the first outer layer 210.
The amount of polymer in the first outer layer 210 is preferably 90.0 wt% to 100 wt%, more preferably 95.0 wt% to 100 wt%.

The first outer resin may further contain an optional component in combination with the polymer. As an arbitrary component, the same component as mentioned as an arbitrary component which the intermediate | middle layer 230 can contain is mentioned, for example.

The glass transition temperature Tg _O1 of the first outer resin is preferably lower than the glass transition temperature Tg _C of the intermediate resin. Further, the difference Tg _C −Tg _O1 between the glass transition temperature Tg _O1 of the first outer resin and the glass transition temperature Tg _C of the intermediate resin is preferably 30 ° C. or higher, more preferably 33 ° C. or higher, particularly preferably 35 ° C. or higher. It is. When the glass transition temperature difference Tg _C -Tg _O1 falls within the above range, the amount of bleed of the additive contained in the intermediate resin into the first outer resin can be suppressed. The upper limit of the glass transition temperature difference Tg _C -Tg _O1 is preferably 55 ° C. or less, more preferably 50 ° C. or less, and particularly preferably 45 ° C. or less. When the difference in glass transition temperature Tg _C -Tg _O1 is not more than the above upper limit value, the adhesion between the first outer resin and the intermediate resin can be improved.

The method for adjusting the difference Tg _C -Tg _O1 in the glass transition temperature is not particularly limited. For example, when the intermediate resin contains a component other than the polymer (for example, a laser absorber, optional component), the glass transition temperature Tg _C of the intermediate resin can be adjusted by the type and amount of the component other than the polymer. Therefore, the glass transition temperature difference Tg _C -Tg _O1 may be adjusted by adjusting the type and amount of components other than the polymer contained in the intermediate resin.

The thickness of the first outer layer 210 is preferably 3 μm or more, more preferably 5 μm or more, particularly preferably 7 μm or more, preferably 15 μm or less, more preferably 13 μm or less, and particularly preferably 10 μm or less. When the thickness of the 1st outer side layer 210 is more than the lower limit of the said range, the bleed-out of the component contained in the intermediate | middle layer 230 can be suppressed effectively. Moreover, when the thickness of the 1st outer side layer 210 is below the upper limit of the said range, the resin layer 200 can be made thin.

The second outer layer 220 is usually formed of a resin containing a polymer. Hereinafter, the resin forming the second outer layer 220 is appropriately referred to as “second outer resin”. As the second outer resin, any resin selected from the range of resins described as the first outer resin can be used. Therefore, the content component of the second outer resin can be selected and applied from the range described as the content component of the first outer resin. Thereby, the same advantage as described in the description of the first outer layer 210 can be obtained.

The glass transition temperature Tg _O2 of the second outer resin is preferably lower than the glass transition temperature Tg _C of the intermediate resin. Further, the difference Tg _C -Tg _{O 2} between the glass transition temperature Tg _{O 2} of the second outer resin and the glass transition temperature Tg _C of the intermediate resin is preferably 30 ° C. or higher, more preferably 33 ° C. or higher, particularly preferably 35 ° C. or higher. It is. Thereby, the amount of bleeding of the additive contained in the intermediate resin into the second outer resin can be suppressed. The upper limit of the glass transition temperature difference Tg _C -Tg _{O 2} is preferably 55 ° C. or lower, more preferably 50 ° C. or lower, and particularly preferably 45 ° C. or lower. When the difference Tg _C -Tg _{O 2 in} the glass transition temperature is not more than the above upper limit, the adhesion between the second outer resin and the intermediate resin can be improved.
The glass transition temperature difference Tg _C -Tg _{O 2} can be adjusted by the same method as the glass transition temperature difference Tg _C -Tg _{O 1} , for example.

The second outer resin may be a resin different from the first outer resin, or may be the same resin as the first outer resin. Among these, it is preferable to use the same resin as the first outer resin and the second outer resin. By using the same resin as the first outer resin and the second outer resin, the manufacturing cost of the resin layer 200 can be suppressed, and curling of the substrate can be suppressed.

The thickness of the second outer layer 220 can be any thickness selected from the range described as the thickness range of the first outer layer 210. Thereby, the same advantage as described in the description of the thickness of the first outer layer 210 can be obtained. In particular, the thickness of the second outer layer 220 is preferably the same as that of the first outer layer 210 in order to suppress curling of the substrate.

Further, the resin layer included in the base material is not limited to a multilayer structure layer including two or more layers like the resin layer 200 shown in FIG. 2, and is a single layer structure layer including only one layer. May be. For example, the resin layer may be a single-layered layer formed of a resin containing a polymer and a laser absorber, and further containing an optional component such as an ultraviolet absorber as necessary. As a specific example, the above-described intermediate layer itself may be used alone as a resin layer.

The amount of the volatile component contained in the resin layer is preferably 0.1% by weight or less, more preferably 0.05% by weight or less, and further preferably 0.02% by weight or less. When the amount of the volatile component is within the above range, the dimensional stability of the resin layer is improved, and the change with time in optical characteristics such as retardation can be reduced. Furthermore, the deterioration of the polarizer and the display device can be suppressed, and the display of the display device can be stably and satisfactorily maintained for a long time. Here, the volatile component is a substance having a molecular weight of 200 or less. Examples of volatile components include residual monomers and solvents. The amount of volatile components can be quantified by analyzing by gas chromatography as the sum of substances having a molecular weight of 200 or less.

The saturated water absorption rate of the resin layer is preferably 0.05% or less, more preferably 0.03% or less, particularly preferably 0.01% or less, and ideally 0%. Since the saturated water absorption rate of the resin layer is thus low, it is possible to suppress changes over time in the optical characteristics of the resin layer.

The saturated water absorption rate of the resin layer can be measured according to the following procedure according to JIS K7209.
The resin layer is dried at 50 ° C. for 24 hours and allowed to cool in a desiccator. Next, the weight (M1) of the dried resin layer is measured.
This resin layer is immersed in water in a room at a temperature of 23 ° C. and a relative humidity of 50% for 24 hours to saturate the resin layer with water. Thereafter, the resin layer is taken out of the water, and the weight (M2) of the resin layer after being immersed for 24 hours is measured.
From the measured values of these weights, the saturated water absorption rate of the resin layer can be obtained by the following formula.
Saturated water absorption (%) = [(M2−M1) / M1] × 100 (%)

The thickness of the resin layer is preferably 15 μm or more, more preferably 20 μm or more, particularly preferably 25 μm or more, preferably 50 μm or less, more preferably 45 μm or less, and particularly preferably 40 μm or less.

There is no limitation on the method for producing the resin layer. For example, the resin layer 200 including the first outer layer 210, the intermediate layer 230, and the second outer layer 220 as shown in FIG. 2 is manufactured by a manufacturing method including a step of forming a resin for forming each layer into a film shape. Can be manufactured. Examples of the resin molding method include a co-extrusion method and a co-casting method. Among these molding methods, the coextrusion method is preferable because it is excellent in production efficiency and hardly causes volatile components to remain in the obtained resin layer.

Further, the resin layer included in the base material may be a stretched film. Therefore, for example, the resin layer 200 including the first outer layer 210, the intermediate layer 230, and the second outer layer 220 as shown in FIG. 2 is formed into a film by the above-described method and then subjected to a stretching process. It may be. The stretched film is a film that has been subjected to a stretching treatment, and usually the polymer in the film is oriented by the stretching treatment. Therefore, the stretched film can have optical characteristics corresponding to the orientation of the polymer, so that optical characteristics such as retardation can be easily adjusted. In addition, the stretched film can usually be reduced in thickness by stretching, a wide film can be obtained, or the mechanical strength can be improved. Therefore, the base material which has a suitable attribute can be easily obtained by using a stretched film as a resin layer.

[2.1.4. Optically anisotropic layer that can be contained in substrate]
The base material may include an optically anisotropic layer formed of a cured product of a liquid crystal composition containing a liquid crystal compound. Here, the term “liquid crystal composition” includes not only a material containing two or more types of components but also a material containing only one type of liquid crystal compound. Usually, the cured product of the liquid crystal composition has optical anisotropy corresponding to the liquid crystal compound, and thus the optically anisotropic layer formed of the cured product has a predetermined in-plane retardation. In the following description, in order to distinguish from the optically anisotropic layer that can be included in the retardation film, the optically anisotropic layer included in the base material may be referred to as a “first optically anisotropic layer”.

A liquid crystal compound is a compound that can exhibit a liquid crystal phase when blended and aligned in a liquid crystal composition. As such a liquid crystal compound, a polymerizable liquid crystal compound is usually used. Here, the polymerizable liquid crystal compound is a liquid crystal compound that is polymerized in a liquid crystal composition in a state of exhibiting a liquid crystal phase, and can be a polymer while maintaining molecular orientation in the liquid crystal phase.

Examples of the polymerizable liquid crystal compound include compounds such as a liquid crystal compound having a polymerizable group, a compound capable of forming a side chain type liquid crystal polymer, and a discotic liquid crystal compound. Among them, light such as visible light, ultraviolet light, and infrared light is used. A photopolymerizable compound that can be polymerized by irradiating is preferred. Examples of the liquid crystal compound having a polymerizable group include, for example, JP-A Nos. 11-513360, 2002-030042, 2004-204190, 2005-263789, and 2007-119415. And rod-like liquid crystal compounds having a polymerizable group described in JP-A No. 2007-186430 and the like. Examples of the side chain type liquid crystal polymer compound include side chain type liquid crystal polymer compounds described in JP-A No. 2003-177242. Further, examples of preferable liquid crystal compounds include “LC242” manufactured by BASF and the like. As specific examples of the discotic liquid crystal compound, JP-A-8-50206, literature (C. Destrade et al., Mol. Cryst. Liq. Cryst., Vol. 71, page 111 (1981); edited by the Chemical Society of Japan) , Quarterly Chemistry Review, No. 22, Liquid Crystal Chemistry, Chapter 5, Chapter 10, Section 2 (1994); J. Zhang et al., J. Am. Chem. Soc., Vol. 116, page 2655 ( 1994)); J. Lehn et al., J. Chem. Soc., Chem. Commun., Page 1794 (1985). A liquid crystal compound may be used individually by 1 type, and may be used combining two or more types by arbitrary ratios.

The liquid crystal compound may be a reverse wavelength dispersive liquid crystal compound. Here, the reverse wavelength dispersive liquid crystal compound refers to a liquid crystal compound exhibiting reverse wavelength dispersion characteristics when homogeneously oriented. Also, the liquid crystal compound is homogeneously aligned means that a layer containing the liquid crystal compound is formed and the major axis direction of the mesogens of the molecules of the liquid crystal compound in the layer is aligned in one direction parallel to the plane of the layer. It means to make it. When the liquid crystal compound contains a plurality of types of mesogens having different alignment directions, the direction in which the longest type of mesogens is aligned is the alignment direction. Whether or not the liquid crystal compound is homogeneously aligned and the alignment direction are determined by measuring the slow axis direction using a phase difference meter represented by AxoScan (manufactured by Axometrics) and the incident angle in the slow axis direction. It can be confirmed by measuring the retardation distribution for each. By using a reverse wavelength dispersive liquid crystal compound as a part or all of the liquid crystal compound included in the liquid crystal composition, a first optical anisotropic layer exhibiting reverse wavelength dispersion characteristics can be easily obtained.

For example, a compound containing a main chain mesogen and a side chain mesogen bonded to the main chain mesogen in the molecule of the compound is preferably used as the liquid crystal compound, and more preferably used as the reverse wavelength dispersive liquid crystal compound. . In the reverse wavelength dispersive liquid crystal compound containing a main chain mesogen and a side chain mesogen, the side chain mesogen can be aligned in a direction different from the main chain mesogen in a state where the reverse wavelength dispersive liquid crystal compound is aligned. In such a case, birefringence appears as the difference between the refractive index corresponding to the main chain mesogen and the refractive index corresponding to the side chain mesogen, and as a result, when the reverse wavelength dispersive liquid crystal compound is homogeneously oriented, Inverse chromatic dispersion characteristics can be shown.

Examples of the reverse wavelength dispersible liquid crystal compound having polymerizability include compounds represented by the following formula (I).

In the formula (I), Y ¹ to Y ⁸ are each independently a chemical single bond, —O—, —S—, —O—C (═O) —, —C (═O) —. O—, —O—C (═O) —O—, —NR ¹ —C (═O) —, —C (═O) —NR ¹ —, —O—C (═O) —NR ¹ —, —NR ¹ —C (═O) —O—, —NR ¹ —C (═O) —NR ¹ —, —O—NR ¹ —, or —NR ¹ —O— is represented. Here, R ¹ represents a hydrogen atom or an alkyl group having 1 to 6 carbon atoms.

In the formula (I), G ¹ and G ² each independently represent a divalent aliphatic group having 1 to 20 carbon atoms, which may have a substituent. The aliphatic group includes one or more —O—, —S—, —O—C (═O) —, —C (═O) —O—, —O—C per aliphatic group. (═O) —O—, —NR ² —C (═O) —, —C (═O) —NR ² —, —NR ² —, or —C (═O) — may be present. Good. However, the case where two or more of —O— or —S— are adjacent to each other is excluded. Here, R ² represents a hydrogen atom or an alkyl group having 1 to 6 carbon atoms.

In the formula (I), Z ¹ and Z ² each independently represents an alkenyl group having 2 to 10 carbon atoms which may be substituted with a halogen atom.

In the formula (I), A ^x represents an organic group having 2 to 30 carbon atoms having at least one aromatic ring selected from the group consisting of an aromatic hydrocarbon ring and an aromatic heterocyclic ring. “Aromatic ring” means a cyclic structure having a broad sense of aromaticity according to the Huckle rule, that is, a cyclic conjugated structure having (4n + 2) π electrons, and sulfur, oxygen, typified by thiophene, furan, benzothiazole, etc. It means a cyclic structure in which a lone electron pair of a hetero atom such as nitrogen is involved in the π-electron system and exhibits aromaticity.

In the formula (I), A ^y is a hydrogen atom, an optionally substituted alkyl group having 1 to 20 carbon atoms, an optionally substituted alkenyl group having 2 to 20 carbon atoms, A cycloalkyl group having 3 to 12 carbon atoms which may have a substituent, an alkynyl group having 2 to 20 carbon atoms which may have a substituent, —C (═O) —R ³ , —SO ₂ An organic group having 2 to 30 carbon atoms having at least one aromatic ring selected from the group consisting of —R ⁴ , —C (═S) NH—R ⁹ , or an aromatic hydrocarbon ring and an aromatic heterocyclic ring; To express. Here, R ³ has an optionally substituted alkyl group having 1 to 20 carbon atoms, an optionally substituted alkenyl group having 2 to 20 carbon atoms, and a substituent. Or a cycloalkyl group having 3 to 12 carbon atoms or an aromatic hydrocarbon ring group having 5 to 12 carbon atoms. R ⁴ represents an alkyl group having 1 to 20 carbon atoms, an alkenyl group having 2 to 20 carbon atoms, a phenyl group, or a 4-methylphenyl group. R ⁹ is an optionally substituted alkyl group having 1 to 20 carbon atoms, an optionally substituted alkenyl group having 2 to 20 carbon atoms, and an optionally substituted carbon. It represents a cycloalkyl group having 3 to 12 carbon atoms or an aromatic group having 5 to 20 carbon atoms which may have a substituent. The aromatic ring which said ^Ax and ^Ay have may have a substituent. A ^x and A ^y may be combined to form a ring.

In the formula (I), A ¹ represents a trivalent aromatic group which may have a substituent.
In the formula (I), A ² and A ³ each independently represent a C 3-30 divalent alicyclic hydrocarbon group which may have a substituent.
In the formula (I), A ⁴ and A ⁵ each independently represents a divalent aromatic group having 6 to 30 carbon atoms which may have a substituent.
In the formula (I), Q ¹ represents a hydrogen atom or an alkyl group having 1 to 6 carbon atoms which may have a substituent.
In the formula (I), each m independently represents 0 or 1.

Examples of the liquid crystal compound represented by the formula (I) include compounds described in International Publication No. 2014/069515, International Publication No. 2015/064581, and the like.

Further, the liquid crystal compound may be a forward wavelength dispersive liquid crystal compound. Here, the forward wavelength dispersible liquid crystal compound refers to a liquid crystal compound that exhibits forward wavelength dispersion characteristics when homogeneously oriented. By using a forward wavelength dispersible liquid crystal compound as part or all of the liquid crystal compound contained in the liquid crystal composition, a first optical anisotropic layer having forward wavelength dispersion characteristics can be easily obtained.

Examples of the forward wavelength dispersible liquid crystal compound having polymerizability include compounds represented by the following formula (II).
R ^3x -C ^3x -D ^3x -C ^5x -M ^x -C ^6x -D ^4x -C ^4x -R ^4x formula (II)

In formula (II), R ^3x and R ^4x each independently represent a reactive group. R ^3x and R ^4x are, for example, (meth) acryloyl group, epoxy group, thioepoxy group, oxetane group, thietanyl group, aziridinyl group, pyrrole group, fumarate group, cinnamoyl group, isocyanate group, isothiocyanate group, amino group, hydroxyl group Group, carboxyl group, alkoxysilyl group, oxazoline group, mercapto group, vinyl group, allyl group and the like.

In the formula (II), D ^3x and D ^4x each independently represent a single bond, a linear or branched alkylene group having 1 to 20 carbon atoms, and a straight chain having 1 to 20 carbon atoms. It represents a group selected from the group consisting of a chain or branched alkylene oxide group.

In the formula (II), C ^3x to C ^6x are each independently a single bond, —O—, —S—, —SS—, —CO—, —CS—, —OCO—, —CH _2. _{-, - OCH 2 -, -} CH = N-N = CH -, - NHCO -, - OCOO -, - CH 2 COO-, and represents a group selected from the group consisting of _-CH 2 OCO-.

In the formula (II), M ^x represents a mesogenic group. Suitable mesogenic groups M ^x are unsubstituted or optionally substituted azomethines, azoxys, phenyls, biphenyls, terphenyls, naphthalenes, anthracenes, benzoates, cyclohexanecarboxylic acids 2-4 skeletons selected from the group consisting of acid phenyl esters, cyanophenylcyclohexanes, cyano-substituted phenylpyrimidines, alkoxy-substituted phenylpyrimidines, phenyldioxanes, tolans, alkenylcyclohexylbenzonitriles, O—, —S—, —S—S—, —CO—, —CS—, —OCO—, —CH ₂ —, —OCH ₂ —, —CH═N—N═CH—, —NHCO—, — OCOO _-, - CH 2 _COO-, and is formed are joined by a linking group of _-CH 2 OCO- or the like.

Examples of the substituent that the mesogenic group M ^x may have include, for example, a halogen atom, an optionally substituted alkyl group having 1 to 10 carbon atoms, a cyano group, a nitro group, —O—R ^5x , —O—. C (═O) —R ^5x , —C (═O) —O—R ^5x , —O—C (═O) —O—R ^5x , —NR ^5x —C (═O) —R ^5x , —C (═O) —NR ^5x R ^7x , or —O—C (═O) —NR ^5x R ^7x . Here, R ^5x and R ^7x represent a hydrogen atom or an alkyl group having 1 to 10 carbon atoms. When R ^5x and R ^7x are alkyl groups, the alkyl group includes —O—, —S—, —O—C (═O) —, —C (═O) —O—, —O—C. (═O) —O—, —NR ^6x —C (═O) —, —C (═O) —NR ^6x —, —NR ^6x —, or —C (═O) — may be present. (However, the case where two or more of —O— and —S— are adjacent to each other is excluded). Here, R ^6x represents a hydrogen atom or an alkyl group having 1 to 6 carbon atoms.

Examples of the substituent in the “optionally substituted alkyl group having 1 to 10 carbon atoms” include, for example, a halogen atom, a hydroxyl group, a carboxyl group, a cyano group, an amino group, and 1 to 6 carbon atoms. An alkoxy group having 2 to 8 carbon atoms, an alkoxyalkoxyalkoxy group having 3 to 15 carbon atoms, an alkoxycarbonyl group having 2 to 7 carbon atoms, and an alkyl having 2 to 7 carbon atoms Examples thereof include a carbonyloxy group and an alkoxycarbonyloxy group having 2 to 7 carbon atoms.

Examples of the liquid crystal compound represented by the formula (II) include rod-like liquid crystal compounds described in International Publication No. 2016/002765.

Also, one type of liquid crystal compound may be used alone, or two or more types may be used in combination at any ratio.

The amount of the liquid crystal compound in the liquid crystal composition can be arbitrarily set within a range in which a desired first optically anisotropic layer can be obtained, preferably 1% by weight or more, more preferably 5% by weight or more, and particularly preferably 10% by weight. Further, it is preferably 100% by weight or less, more preferably 80% by weight or less, and particularly preferably 60% by weight or less.

The liquid crystal composition may contain an arbitrary component in combination with the liquid crystal compound. Optional components include, for example, polymerization initiators, surfactants, solvents, metals, metal complexes, dyes, pigments, fluorescent materials, phosphorescent materials, leveling agents, thixotropic agents, gelling agents, polysaccharides, infrared absorbers, Examples thereof include antioxidants, ion exchange resins, and metal oxides such as titanium oxide. Reference may be made to WO 2015/064581 for optional ingredients.

The first optically anisotropic layer is a layer formed of a cured product of a liquid crystal composition containing the above liquid crystal compound, and usually contains cured liquid crystal molecules obtained from the liquid crystal compound. Here, the “cured liquid crystal molecule” means a molecule of the compound when the compound capable of exhibiting the liquid crystal phase is turned into a solid while exhibiting the liquid crystal phase. The cured liquid crystal molecules contained in the first optically anisotropic layer are usually polymers obtained by polymerizing a liquid crystal compound. Therefore, the first optically anisotropic layer usually comprises a polymer obtained by polymerizing a liquid crystal compound, and is a resin layer that can contain any component as necessary. And such a 1st optically anisotropic layer can have the optical anisotropy according to the orientation state of the said hardening liquid crystal molecule. The optical anisotropy of the first optical anisotropic layer can be expressed by in-plane retardation. The specific in-plane retardation of the first optical anisotropic layer can be set according to the in-plane retardation that the first optical anisotropic layer should have.

The thickness of the first optically anisotropic layer can be adjusted as appropriate so that the optical properties such as retardation can be in a desired range, preferably 0.5 μm or more, more preferably 1.0 μm or more, and preferably 10 μm or less. More preferably, it is 7 μm or less, particularly preferably 5 μm or less.

The first optically anisotropic layer usually comprises a step of forming a liquid crystal composition layer on a support and a step of curing the liquid crystal composition layer to obtain a first optically anisotropic layer. It can be manufactured by a method.

In this production method, a support is prepared, and a layer of a liquid crystal composition is formed on the surface of the support. As the support, a resin film is usually used. As the resin, a thermoplastic resin can be used. Among these, a resin containing an alicyclic structure-containing polymer and a cellulose ester resin are preferred from the viewpoints of transparency, low hygroscopicity, dimensional stability, and lightness.

The surface of the support may be subjected to a treatment for imparting alignment regulating force in order to promote the alignment of the liquid crystal compound in the liquid crystal composition layer. Here, the alignment regulating force of a certain surface means the property of that surface capable of aligning the liquid crystal compound in the liquid crystal composition.

Examples of the treatment for imparting the orientation regulating force include a rubbing treatment, an orientation layer forming treatment, an ion beam orientation treatment, and a stretching treatment. Among them, the stretching treatment is preferable. By subjecting the support to stretching under appropriate conditions, the polymer molecules contained in the support can be oriented. Thereby, the alignment control force which orientates a liquid crystal compound in the alignment direction of the molecule | numerator of the polymer contained in a support body can be provided to the surface of a support body.

The stretching of the support is preferably performed so that anisotropy is imparted to the support so that the slow axis can be expressed in the support. Thereby, usually, an alignment regulating force for aligning the liquid crystal compound in a direction parallel or perpendicular to the slow axis of the support is applied to the surface of the support. For example, when a resin having a positive intrinsic birefringence value is used as the support material, the slow axis parallel to the stretching direction is usually obtained by orienting the polymer molecules contained in the support in the stretching direction. Therefore, the alignment regulating force for aligning the liquid crystal compound in a direction parallel to the slow axis of the support is imparted to the surface of the support. Therefore, the extending direction of the support can be set according to the desired alignment direction in which the liquid crystal compound is to be aligned.

The stretching ratio can be set so that the birefringence Δn of the support after stretching falls within a desired range. The birefringence Δn of the support after stretching is preferably 0.000050 or more, more preferably 0.000070 or more, preferably 0.007500 or less, more preferably 0.007000 or less. When the birefringence Δn of the support after stretching is not less than the lower limit of the above range, it is possible to impart a good alignment regulating force to the surface of the support. The stretching can be performed using a stretching machine such as a tenter stretching machine.

It is preferable to use a long film as the support. By using a long film as the support, the productivity of the first optically anisotropic layer can be improved. At this time, the thickness of the support is preferably 1 μm or more, more preferably 5 μm or more, particularly preferably 30 μm or more, preferably 1000 μm or less, from the viewpoint of facilitating productivity improvement, thinning and weight reduction. More preferably, it is 300 micrometers or less, Most preferably, it is 100 micrometers or less.

Further, as the support, the above-described resin layer may be used. By using the resin layer to be included in the base material as a support, it is not necessary to prepare a support separately from the material of the base material, so that the manufacturing cost of the base material can be reduced.

The formation of the liquid crystal composition layer is usually carried out by a coating method. Specifically, the liquid crystal composition is applied to the surface of the support to form a liquid crystal composition layer. Examples of coating methods include curtain coating, extrusion coating, roll coating, spin coating, dip coating, bar coating, spray coating, slide coating, print coating, gravure coating, and die coating. Method, gap coating method, and dipping method. The thickness of the layer of the liquid crystal composition to be applied can be appropriately set according to a desired thickness required for the first optical anisotropic layer.

After forming the liquid crystal composition layer, if necessary, a step of drying the liquid crystal composition layer may be performed. Such drying can be achieved by a drying method such as natural drying, heat drying, reduced pressure drying, and reduced pressure heat drying. By such drying, the solvent can be removed from the liquid crystal composition layer.

In addition, after forming the liquid crystal composition layer, a step of aligning the liquid crystal compound contained in the layer may be performed as necessary. In this step, the liquid crystal compound is usually aligned in a direction corresponding to the alignment regulating force of the surface of the support by applying an alignment treatment to the liquid crystal composition layer. The alignment treatment is usually performed by heating the liquid crystal composition layer to a predetermined alignment temperature. The conditions for the alignment treatment can be appropriately set according to the properties of the liquid crystal composition to be used. As a specific example of the conditions for the alignment treatment, the treatment may be performed under a temperature condition of 50 ° C. to 160 ° C. for 30 seconds to 5 minutes.

However, alignment of the liquid crystal compound may be achieved immediately by application of the liquid crystal composition. Therefore, even when it is desired to align the liquid crystal compound, the alignment treatment is not necessarily performed on the layer of the liquid crystal composition.

If necessary, after drying the liquid crystal composition layer and aligning the liquid crystal compound, the liquid crystal composition layer is cured to obtain a first optically anisotropic layer. In this step, the liquid crystal compound is usually polymerized to cure the liquid crystal composition layer. As a method for polymerizing the liquid crystal compound, a method suitable for the properties of the components contained in the liquid crystal composition can be selected. Examples of the polymerization method include a method of irradiating active energy rays and a thermal polymerization method. Among them, the method of irradiating with active energy rays is preferable because heating is unnecessary and the polymerization reaction can proceed at room temperature. Here, the irradiated active energy rays can include light such as visible light, ultraviolet light, and infrared light, and arbitrary energy rays such as electron beams.

Among these, a method of irradiating light such as ultraviolet rays is preferable because the operation is simple. The temperature at the time of ultraviolet irradiation is preferably not higher than the glass transition temperature of the support, preferably not higher than 150 ° C., more preferably not higher than 100 ° C., particularly preferably not higher than 80 ° C. The lower limit of the temperature during ultraviolet irradiation can be 15 ° C. or higher. The irradiation intensity of ultraviolet rays is preferably 0.1 mW / cm ² or more, more preferably 0.5 mW / cm ² or more, preferably 1000 mW / cm ² or less, more preferably 600 mW / cm ² or less.

The first optically anisotropic layer thus obtained may be peeled off from the support if necessary.

[2.1.5. Conductive layer that can be included in substrate]
The base material may include a conductive layer in combination with the resin layer. The conductive layer is usually provided on one side or both sides of the resin layer included in the substrate. Since the resin layer is generally excellent in flexibility, a touch panel in which input with a finger is smooth can be realized by using a base material provided with a conductive layer on the resin layer. In particular, in a base material containing an alicyclic structure-containing polymer, the excellent heat resistance and low hygroscopicity of the alicyclic structure-containing polymer can be utilized. hard.

As the conductive layer, for example, a layer containing at least one conductive material selected from the group consisting of conductive metal oxides, conductive nanowires, metal meshes, and conductive polymers can be used.

Examples of the conductive metal oxide include ITO (indium tin oxide), IZO (indium zinc oxide), ZnO (zinc oxide), IWO (indium tungsten oxide), ITiO (indium titanium oxide), and AZO (aluminum zinc oxide). , GZO (gallium zinc oxide), XZO (zinc-based special oxide), IGZO (indium gallium zinc oxide), and the like. Among these, ITO is particularly preferable from the viewpoints of light transmittance and durability. One of these may be used alone, or two or more of these may be used in combination at any ratio.

Conductive layers containing conductive metal oxides are vapor deposition, sputtering, ion plating, ion beam assisted vapor deposition, arc discharge plasma vapor deposition, thermal CVD, plasma CVD, plating, and combinations thereof. The film formation method can be used. Among these, the vapor deposition method and the sputtering method are preferable, and the sputtering method is particularly preferable. In the sputtering method, since a conductive layer having a uniform thickness can be formed, it is possible to suppress the generation of locally thin portions in the conductive layer.

The conductive nanowire is a conductive substance having a needle-like or thread-like shape and a diameter of nanometer. The conductive nanowire may be linear or curved. Such a conductive nanowire can form a good electrical conduction path even with a small amount of conductive nanowires by forming gaps between the conductive nanowires and forming a mesh. A small conductive layer can be realized. In addition, since the conductive wire has a mesh shape, an opening is formed in the mesh space, so that a conductive layer having high light transmittance can be obtained. Furthermore, by using a conductive layer containing conductive nanowires, it is usually possible to obtain a substrate having excellent bending resistance.

The ratio between the thickness d and the length L of the conductive nanowire (aspect ratio: L / d) is preferably 10 to 100,000, more preferably 50 to 100,000, and particularly preferably 100 to 100,000. 10,000. When conductive nanowires having a large aspect ratio are used in this way, the conductive nanowires can cross well and high conductivity can be expressed by a small amount of conductive nanowires. As a result, a substrate having excellent transparency can be obtained. Here, “the thickness of the conductive nanowire” means the diameter when the cross section of the conductive nanowire is circular, the short diameter when the cross section of the conductive nanowire is circular, and the polygonal shape Means the longest diagonal. The thickness and length of the conductive nanowire can be measured by a scanning electron microscope or a transmission electron microscope.

The thickness of the conductive nanowire is preferably less than 500 nm, more preferably less than 200 nm, still more preferably 10 nm to 100 nm, and particularly preferably 10 nm to 50 nm. Thereby, the transparency of a conductive layer can be improved.

The length of the conductive nanowire is preferably 2.5 μm to 1000 μm, more preferably 10 μm to 500 μm, and particularly preferably 20 μm to 100 μm. Thereby, the electroconductivity of a conductive layer can be improved.

Examples of conductive nanowires include metal nanowires made of metal, conductive nanowires containing carbon nanotubes, and the like.

The content of the conductive nanowire in the conductive layer is preferably 80% by weight to 100% by weight, more preferably 85% by weight to 99% by weight, with respect to the total weight of the conductive layer. Thereby, the electroconductive layer excellent in electroconductivity and light transmittance can be obtained.

The conductive layer containing conductive nanowires can be produced by coating and drying a conductive nanowire dispersion obtained by dispersing conductive nanowires in a solvent.

The metal mesh is a thin metal wire formed in a lattice shape. As the metal contained in the metal mesh, a highly conductive metal is preferable. Examples of suitable metals include gold, platinum, silver and copper, among which silver, copper and gold are preferred, and silver is more preferred. These metals may be used individually by 1 type, and may be used combining two or more types by arbitrary ratios.

The conductive layer containing a metal mesh can be formed, for example, by applying a conductive layer forming composition containing a silver salt and forming fine metal wires in a predetermined lattice pattern by exposure processing and development processing. The conductive layer containing a metal mesh can also be formed by printing a conductive layer forming composition containing metal fine particles in a predetermined pattern. JP-A-2012-18634 and JP-A-2003-331654 may be referred to for details of such a conductive layer and a method for forming the conductive layer.

Examples of conductive polymers include polythiophene polymers, polyacetylene polymers, polyparaphenylene polymers, polyaniline polymers, polyparaphenylene vinylene polymers, polypyrrole polymers, polyphenylene polymers, and polyester polymers modified with acrylic polymers. Examples thereof include polymers. Among these, polythiophene polymers, polyacetylene polymers, polyparaphenylene polymers, polyaniline polymers, polyparaphenylene vinylene polymers, and polypyrrole polymers are preferable. Among these, a polythiophene polymer is particularly preferable. By using a polythiophene polymer, a conductive layer having excellent transparency and chemical stability can be obtained. Specific examples of the polythiophene-based polymer include: polythiophene; poly (3-C _1-8 alkyl-thiophene) such as poly (3-hexylthiophene); poly (3,4-ethylenedioxythiophene), poly (3,4 -Propylenedioxythiophene), poly [3,4- (1,2-cyclohexylene) dioxythiophene] and other poly (3,4- (cyclo) alkylenedioxythiophene); polythienylene vinylene and the like .
Moreover, the said conductive polymer may be used individually by 1 type, and may be used combining two or more types by arbitrary ratios.

The conductive layer containing a conductive polymer can be formed, for example, by applying a conductive composition containing a conductive polymer and drying it. JP, 2011-175601, A can be referred to for a conductive layer containing a conductive polymer.

The conductive layer may be formed in the entire in-plane direction of the base material, but may be patterned in a predetermined pattern. The shape of the pattern of the conductive layer is preferably a pattern that operates well as a touch panel (for example, a capacitive touch panel). For example, JP 2011-511357 A, JP 2010-164938 A, JP 2008-310550 A And the patterns described in JP-A No. 2003-511799 and JP-A 2010-541109.

The surface resistance value of the conductive layer is preferably 2000Ω / □ or less, more preferably 1500Ω / □ or less, and particularly preferably 1000Ω / □ or less. When the surface resistance value of the conductive layer is thus low, a high-performance touch panel can be realized using a base material. Although there is no particular limitation on the lower limit of the surface resistance value of the conductive layer, it is preferably 100Ω / □ or more, more preferably 200Ω / □ or more, and particularly preferably 300Ω / □ or more because of easy production.

The light transmittance of the conductive layer in the wavelength range of 400 nm to 700 nm is preferably 85% or more, more preferably 90% or more, and further preferably 95% or more.

The thickness of the conductive layer is preferably 0.01 μm to 10 μm, more preferably 0.05 μm to 3 μm, and particularly preferably 0.1 μm to 1 μm.

[2.1.6. Optical properties and thickness of substrate]
The substrate described above can usually function as a λ / 4 plate. Here, the λ / 4 plate refers to a member having in-plane retardation within a predetermined range at a wavelength of 550 nm. Specifically, the in-plane retardation of the λ / 4 plate at a wavelength of 550 nm is usually 110 nm or more, preferably 120 nm or more, more preferably 125 nm or more, and usually 165 nm or less, preferably 155 nm or less, more preferably 150 nm or less. It is. Therefore, a base material that can function as a λ / 4 plate refers to a base material having in-plane retardation in the above range at a wavelength of 550 nm. A circularly polarizing plate can be obtained by combining a substrate that can function as a λ / 4 plate with a polarizer.

The base material preferably has a high light transmittance at a visible wavelength from the viewpoint of improving the display quality of the display device. For example, the light transmittance of the substrate in the wavelength range of 400 nm to 700 nm is preferably 85% to 100%, more preferably 87% to 100%, and particularly preferably 90% to 100%.

The base material preferably has a small haze from the viewpoint of enhancing the image clarity of the display device. The specific haze of the substrate is preferably 1% or less, more preferably 0.8% or less, and particularly preferably 0.5% or less. The haze can be measured using a turbidimeter in accordance with JIS K7361-1997.

When the substrate is a single layer, the thickness of the substrate is preferably 10 μm or more, more preferably 15 μm or more, particularly preferably 20 μm or more, preferably 100 μm or less, more preferably 80 μm or less, particularly preferably 60 μm or less. It is. When the substrate is a multilayer, the thickness of each layer is preferably 10 μm or more, more preferably 15 μm or more, particularly preferably 20 μm or more, preferably 100 μm or less, more preferably 80 μm or less, and particularly preferably 60 μm or less. .

[2.1.7. First structural example of substrate]
Hereinafter, a specific configuration example of the substrate will be described with reference to the drawings.
FIG. 3 is a cross-sectional view schematically showing a base material 300 as an example. As shown in FIG. 3, the substrate 300 according to this example has a first substrate layer 310 having a small in-plane retardation Re (550) at a wavelength of 550 nm and a large in-plane retardation Re (550) at a wavelength of 550 nm. 2nd base material layer 320 and the conductive layer 330 formed in at least one surface 310U of the 1st base material layer 310 are included. The laser absorbent is included in one or both of the first base material layer 310 and the second base material layer 320. FIG. 3 shows an example in which the conductive layer 330 is formed on one surface 310U of the first base material layer 310, but the conductive layer 330 is formed on the other surface 310D of the first base material layer 310. It may be formed on both

surfaces

310U and 310D of the first base material layer 310.

The first base material layer 310 is preferably an optically isotropic layer. Therefore, the in-plane retardation Re (550) and the thickness direction retardation Rth (550) of the first base material layer 310 at a wavelength of 550 nm of the first base material layer are preferably small. Specifically, the in-plane retardation Re (550) at a wavelength of 550 nm of the first base material layer 310 is preferably 10 nm or less, more preferably 5 nm or less, particularly preferably 4 nm or less, and ideally 0 nm. is there. The retardation Rth (550) in the thickness direction at a wavelength of 550 nm of the first base material layer 310 is preferably 15 nm or less, more preferably 13 nm or less, and particularly preferably 10 nm or less. The lower limit is not particularly limited and is ideally 0 nm, but is usually 5 nm or more. Thus, when the 1st base material layer 310 is optically isotropic, when it uses for a display apparatus, coloring of a display screen can be suppressed or a viewing angle characteristic can be improved. The first base material layer 310 may have a single layer structure or a multilayer structure. Examples of the first substrate layer 310 include an alicyclic structure-containing polymer film (for example, ZEONOR film (manufactured by ZEON Corporation)), a triacetyl cellulose (TAC) film, and the like.

The in-plane retardation Re (550) of the second base material layer 320 at a wavelength of 550 nm is preferably 90 nm or more, more preferably 100 nm or more, particularly preferably 110 nm or more, preferably 150 nm or less, more preferably 145 nm. Hereinafter, it is particularly preferably 140 nm or less. Examples of the second base material layer include an obliquely stretched film (Zeonor film ZD series, manufactured by Nippon Zeon Co., Ltd.).
By combining the first base material layer 310 and the second base material layer 320 having such retardation, a base material 300 that can function as a λ / 4 plate can be realized.

As a preferred embodiment of the base material 300, one or both of the first base material layer 310 and the second base material layer 320 include a first outer layer, a second outer layer, the first outer layer and the first base layer. It is a resin layer having a multilayer structure including an intermediate layer provided between two outer layers (see FIG. 2). In such a resin layer, the component contained in the intermediate layer hardly causes bleed out. Therefore, when the intermediate layer includes a component that easily causes bleed-out, the base material 300 can be manufactured while suppressing contamination of the manufacturing equipment due to the bleed-out. Therefore, the laser absorber and the ultraviolet absorber as an optional component are preferably included in the intermediate layer.

In the base material 300 described above, the thickness of one or both of the first base material layer 310 and the second base material layer 320 is preferably 10 μm to 60 μm, more preferably 15 μm to 55 μm, and particularly preferably 20 μm to 50 μm. When the thickness of one or both of the first base material layer 310 and the second base material layer 320 falls within the above range, the self-supporting property of the polarizer protective film itself can be maintained, and the rigidity of the polarizer protective film can be maintained. Can be maintained.

[2.1.8. Second configuration example]
Hereinafter, another specific configuration example of the substrate will be described with reference to the drawings.
FIG. 4 is a cross-sectional view schematically showing a base material 400 as an example. As shown in FIG. 4, the base material 400 according to this example includes a first base material layer 410 that can function as a λ / 4 plate, a second base material layer 420 that can function as a λ / 2 plate, and a first base material. And a conductive layer 430 formed on at least one surface 410U of the layer 410. The laser absorbent is included in one or both of the first base material layer 410 and the second base material layer 420. FIG. 4 shows an example in which the conductive layer 430 is formed on one surface 410U of the first base material layer 410, but the conductive layer 430 is formed on the other surface 410D of the first base material layer 410. It may be formed on both

surfaces

410U and 410D of the first base material layer 410.

The first base material layer 410 is a layer that can function as a λ / 4 plate. Therefore, the first base material layer 410 has in-plane retardation within a predetermined range at a wavelength of 550 nm. Specifically, the in-plane retardation of the first base material layer 410 at a wavelength of 550 nm is usually 110 nm or more, preferably 120 nm or more, more preferably 125 nm or more, and usually 165 nm or less, preferably 155 nm or less, more preferably 150 nm or less.

The second base material layer 420 is a layer that can function as a λ / 2 plate. Here, the λ / 2 plate refers to a layer having in-plane retardation within a predetermined range at a wavelength of 550 nm. Specifically, the in-plane retardation of the λ / 2 plate at a wavelength of 550 nm is usually 240 nm or more, preferably 250 nm or more, usually 300 nm or less, preferably 280 nm or less, and particularly preferably 265 nm or less. Therefore, the second base material layer 420 that can function as a λ / 2 plate refers to a layer having in-plane retardation in the above range at a wavelength of 550 nm.

By including the first base material layer 410 that can function as a λ / 4 plate and the second base material layer 420 that can function as a λ / 2 plate, the base material 400 can function as a broadband λ / 4 plate. Here, the broadband λ / 4 plate refers to a λ / 4 plate that exhibits reverse wavelength dispersion characteristics. Since the broadband λ / 4 plate can exhibit the function as the λ / 4 plate in a wide wavelength range, the display device including the base material 400 that can function as the broadband λ / 4 plate particularly intends for an image observed from the front direction. The coloring which is not performed can be suppressed. Further, by combining a polarizer protective film including a base material 400 that can function as a broadband λ / 4 plate with a polarizer, a circularly polarizing plate that can function in a wide wavelength range can be realized.

However, in order to allow the base material 400 to function as a broadband λ / 4 plate, the crossing angle formed by the slow axis of the first base material layer 410 and the slow axis of the second base material layer 420 is appropriate. It is preferable to adjust to the range.
In general, a λ / 4 plate having a slow axis that forms an angle θ (λ / 4) with respect to a reference direction, and λ / that has a slow axis that forms an angle θ (λ / 2) with respect to the reference direction. When the multilayer film combining the two plates satisfies the formula (X): “θ (λ / 4) = 2θ (λ / 2) + 45 °”, the multilayer film is in the wide wavelength range. This is a broadband λ / 4 plate capable of giving in-plane retardation of approximately ¼ wavelength of the wavelength of the light passing through the film to the front direction (see Japanese Patent Application Laid-Open No. 2007-004120). Therefore, from the viewpoint of obtaining the base material 400 that can function as a broadband λ / 4 plate by combining the first base material layer 410 that can function as a λ / 4 plate and the second base material layer 420 that can function as a λ / 2 plate. The slow axis of the first base material layer 410 that can function as a λ / 4 plate and the slow axis of the second base material layer 420 that can function as a λ / 2 plate are represented by the above formula (X). It is preferable to satisfy a relationship close to. From such a viewpoint, the crossing angle formed by the slow axis of the first base material layer 410 that can function as a λ / 4 plate and the slow axis of the second base material layer 420 that can function as a λ / 2 plate is preferably Is at least 55 °, more preferably at least 57 °, particularly preferably at least 59 °, preferably at most 65 °, more preferably at most 63 °, particularly preferably at most 61 °.

As a preferred embodiment of the base material 400, the second base material layer 420 is preferably a first optical anisotropic layer formed of a cured product of a liquid crystal composition containing a liquid crystal compound. Usually, according to the hardened | cured material of a liquid crystal composition, durability can be raised and it is easy to obtain a large retardation even if it is thin. Therefore, by using the first optical anisotropic layer as the second base material layer 420, the thin base material layer 400 having particularly excellent heat resistance can be obtained.
When using a 1st optically anisotropic layer as the 2nd base material layer 420, as the 1st base material layer 410, the resin layer containing a laser absorber is normally used.

Moreover, as another preferable embodiment of the base material 400, one or both of the first base material layer 410 and the second base material layer 420 are a first outer layer, a second outer layer, and the first base material layer. A resin layer having a multilayer structure including an outer layer and an intermediate layer provided between the second outer layer is preferable (see FIG. 2). In such a resin layer, from the viewpoint of suppressing bleed-out, it is preferable that the laser absorber and the ultraviolet absorber as an optional component are contained in the intermediate layer.

In the base material 400 described above, the thickness of one or both of the first base material layer 410 and the second base material layer 420 is preferably 10 μm to 60 μm, similarly to the first structural example of the base material.

[2.2. Any layer]
The polarizer protective film may further include an arbitrary layer in combination with the base material. Examples of the arbitrary layer include an adhesive layer, an adhesive layer, a hard coat layer, an index matching layer, an easy adhesion layer, an antiglare layer, and an antireflection layer.

[2.3. Characteristics and thickness of polarizer protective film]
The polarizer protective film preferably has a high light transmittance at a visible wavelength from the viewpoint of improving the display quality of the display device. For example, the light transmittance of the polarizer protective film in the wavelength range of 400 nm to 700 nm is preferably 85% to 100%, more preferably 87% to 100%, and particularly preferably 90% to 100%.

In order to suppress deterioration of the polarizer due to external light and ultraviolet rays from the backlight, the light transmittance at a wavelength of 380 nm is preferably 1% or less, more preferably 0.5% or less, and particularly preferably 0.05. % Or less. The light transmittance can be controlled by an ultraviolet absorber.

The polarizer protective film preferably has a small haze from the viewpoint of enhancing the image clarity of the display device. The haze of the polarizer protective film is preferably 1% or less, more preferably 0.8% or less, and particularly preferably 0.5% or less.

The thickness of the polarizer protective film is not particularly limited, but is preferably 10 μm or more, more preferably 15 μm or more, particularly preferably 20 μm or more, preferably 100 μm or less, more preferably 80 μm or less, and particularly preferably 60 μm or less. It is.

[3. Polarizer]
A polarizer is an optical member having a polarization transmission axis and a polarization absorption axis. This polarizer can absorb linearly polarized light having a vibration direction parallel to the polarization absorption axis and pass linearly polarized light having a vibration direction parallel to the polarization transmission axis. Here, the vibration direction of linearly polarized light means the vibration direction of the electric field of linearly polarized light.

As a polarizer, for example, a film of an appropriate vinyl alcohol polymer such as polyvinyl alcohol or partially formalized polyvinyl alcohol, a dyeing treatment with a dichroic substance such as iodine and a dichroic dye, a stretching treatment, a crosslinking treatment, etc. The film which performed the appropriate process of these by the appropriate order and system can be used. This linear polarizer is preferably excellent in the degree of polarization. The thickness of the linear polarizer is generally 5 μm to 80 μm, but is not limited thereto.

From the viewpoint of obtaining a circularly polarizing plate by combining a polarizer protective film containing a base material that can function as a λ / 4 plate and a polarizer, the slow axis of the base material of the polarizer protective film and the transmission axis of the polarizer are: It is preferable that they intersect. At this time, the crossing angle between the slow axis of the substrate and the transmission axis of the polarizer is preferably within a predetermined range. The specific range of the crossing angle is preferably 45 ° ± 5 °, more preferably 45 ° ± 3 °, and particularly preferably 45 ° ± 1 °. When the crossing angle is adjusted to the above range, the linearly polarized light that has passed through the polarizer and entered the polarizer protective film can be converted into circularly polarized light by a base material that can function as a λ / 4 plate. By converting the linearly polarized light that has passed through the polarizer and entered the polarizer protective film into circularly polarized light, the display device with the polarizer protective film arranged on the viewer side can degrade the display quality even when viewed through polarized sunglasses. You can see the display without.

[4. Retardation film]
The retardation film is a film having an in-plane retardation Re (550) of 90 nm to 150 nm at a wavelength of 550 nm. More specifically, the in-plane retardation Re (550) at a wavelength of 550 nm of the retardation film is preferably 90 nm or more, more preferably 95 nm or more, particularly preferably 100 nm or more, preferably 150 nm or less, more preferably 145 nm. Hereinafter, it is particularly preferably 140 nm or less. A retardation film having in-plane retardation Re (550) in such a range can function as a λ / 4 plate. Therefore, a circularly polarizing plate can be obtained by a combination of a retardation film and a polarizer.

From the viewpoint of obtaining a circularly polarizing plate by combining a retardation film and a polarizer, it is preferable that the slow axis of the retardation film and the transmission axis of the polarizer intersect. At this time, the crossing angle between the slow axis of the retardation film and the transmission axis of the polarizer is preferably within a predetermined range. The specific range of the crossing angle is preferably 45 ° ± 5 °, more preferably 45 ° ± 3 °, and particularly preferably 45 ° ± 1 °. When the crossing angle is adjusted to the above range, linearly polarized light that has passed through the polarizer and entered the retardation film can be converted into circularly polarized light by the retardation film.

As the retardation film, for example, a film formed of a resin can be used. As the resin forming the retardation film, a polymer and a resin containing an optional component other than the polymer as necessary can be used. Therefore, as a retardation film, a film containing a polymer and optional components as required can be used. As this film, a single layer structure film or a multilayer structure film may be used.

As the polymer, for example, any polymer selected from the range described as the polymer that can be contained in the substrate can be used, and among them, the alicyclic structure-containing polymer is preferable. By using a retardation film containing an alicyclic structure-containing polymer, a display device having excellent durability can be obtained by utilizing the excellent properties of the alicyclic structure-containing polymer.
The amount of the polymer in the retardation film is preferably 90.0 wt% to 100 wt%, more preferably 95.0 wt% to 100 wt%. By setting the amount of the polymer within the above range, the heat-and-moisture resistance and mechanical strength of the retardation film can be effectively increased.
Moreover, as an arbitrary component, the same component as mentioned as an arbitrary component which can be contained in a base material, for example is mentioned.

The retardation film preferably includes a stretched film. This stretched film is a film obtained by subjecting a resin film to a stretching treatment, and usually the stretched film itself can be used as a retardation film. By using a stretched film, a retardation film can be easily obtained.

Also, as the retardation film, for example, an optically anisotropic layer formed of a cured product of a liquid crystal composition containing a liquid crystal compound may be used. In the following description, in order to distinguish from the first optical anisotropic layer that can be included in the substrate, the optical anisotropic layer as the retardation film may be referred to as a “second optical anisotropic layer”. As the second optical anisotropic layer, a layer included in the range described as the first optical anisotropic layer can be arbitrarily used. Usually, according to the cured product of the liquid crystal composition, durability can be increased, and even if it is thin, it is easy to obtain a large retardation. Therefore, by using the second optical anisotropic layer as a retardation film, Thinning can be achieved.

When the retardation film is the second optically anisotropic layer, the in-plane retardation Re (450) at a wavelength of 450 nm of the retardation film and the in-plane retardation Re (550) at a wavelength of 550 nm of the retardation film are: It is preferable to satisfy Re (450) / Re (550) <1.0. A retardation film having a retardation satisfying Re (450) / Re (550) <1.0 can function as a broadband λ / 4 plate. Therefore, it is possible to obtain a circularly polarizing plate that can function in a wide wavelength range by combining the retardation film and the polarizer. A retardation film having a retardation satisfying Re (450) / Re (550) <1.0 is obtained by using, for example, a liquid crystal composition containing a reverse wavelength dispersion liquid crystal as a material of the second optical anisotropic layer. Obtainable.

The thickness of the retardation film can be appropriately adjusted so that the optical properties such as retardation can be in a desired range, preferably 1.0 μm or more, more preferably 3.0 μm or more, particularly preferably 5.0 μm or more, Preferably it is 100 micrometers or less, More preferably, it is 80 micrometers or less, Most preferably, it is 55 micrometers or less.

[5. Display element]
There are various types of display elements depending on the type of display device. Examples of typical display elements include liquid crystal cells and organic electroluminescence elements (hereinafter sometimes referred to as “organic EL elements” as appropriate).

The liquid crystal cell is, for example, in-plane switching (IPS) mode, vertical alignment (VA) mode, multi-domain vertical alignment (MVA) mode, continuous spin wheel alignment (CPA) mode, hybrid alignment nematic (HAN) mode, twisted nematic A liquid crystal cell of any mode such as (TN) mode, super twisted nematic (STN) mode, or optical compensated bend (OCB) mode can be used. Such a liquid crystal cell is usually provided as a display element in a liquid crystal display device.

An organic EL element usually includes a transparent electrode layer, a light emitting layer, and an electrode layer in this order, and the light emitting layer can generate light when a voltage is applied from the transparent electrode layer and the electrode layer. Examples of the material constituting the organic light emitting layer include polyparaphenylene vinylene-based, polyfluorene-based, and polyvinyl carbazole-based materials. In addition, the light emitting layer may have a stack of layers having different emission colors or a mixed layer in which a different dye is doped in a certain dye layer. Furthermore, the organic EL element may include functional layers such as a barrier layer, a hole injection layer, a hole transport layer, an electron injection layer, an electron transport layer, an equipotential surface forming layer, and a charge generation layer. Such an organic EL element is usually provided as a display element in an organic EL display device.

[6. Any member]
The display device may include an arbitrary member other than the above-described polarizer protective film, polarizer, retardation film, and display element as necessary.
Examples of the optional member include a protective film; an optical compensation film for a liquid crystal cell; an adhesive layer and a pressure-sensitive adhesive layer that adhere members included in the display device; and the like.

[7. Production method]
The display device described above usually includes a step of preparing a polarizer protective film; a step of bonding the polarizer protective film and the polarizer directly or via an arbitrary layer; a polarizer and a retardation film directly or A step of bonding through an arbitrary layer; a step of bonding the retardation film and the display element directly or through an arbitrary layer; a step of cutting the polarizer protective film with a laser beam; Can be manufactured.

In the above manufacturing method, the order of the steps is arbitrary. For example, you may perform the process of bonding a polarizer protective film and a polarizer after the process of cut | disconnecting a polarizer protective film independently. In addition, for example, after the step of bonding the polarizer protective film and the polarizer and the step of bonding the polarizer and the retardation film, the step of cutting the polarizer protective film simultaneously with the polarizer and the retardation film May be performed.

As described above, the display device can usually be manufactured by a manufacturing method including a step of cutting the polarizer protective film with laser light. The conventional polarizer protective film has a film that does not have sufficient absorption of laser light to be cut, but the polarizer protective film having a base material containing a laser absorber can be used alone or In addition, cutting with a laser beam is possible in a state of being bonded to another member such as a polarizer and a retardation film. Therefore, generation of cutting residue can be suppressed or the cut surface can be smoothed, so that a display device with excellent display quality can be obtained. Moreover, since it is a heat-resistant polarizer protective film, a dimensional change is small even in cutting with a laser beam, and a display device with excellent display quality can be obtained. Moreover, since it is a polarizer protective film with solvent resistance, even when it bonds through an adhesive agent, degradation of a polarizer protective film is small and the display apparatus excellent in display quality can be obtained.

As the laser beam, a laser beam having a wavelength that can be absorbed by the laser absorber can be used. Among them, laser light having a wavelength in the infrared region is preferable because it is widely spread as industrial equipment. Among these, laser light having a wavelength in the range of 9 μm to 12 μm is preferable because an output suitable for cutting the polarizer protective film can be efficiently obtained and introduced at a relatively low cost. In particular, a laser beam having a wavelength of 9 μm to 11 μm is more preferable, and a laser beam having a wavelength of 9 μm to 9.5 μm is particularly preferable. Laser light having such a wavelength can be stably output when a carbon dioxide laser device is used as the laser device.

As the laser light, a Gaussian mode laser light or a laser light having a top hat energy distribution may be used. Among these, as the laser light, it is preferable to use laser light exhibiting a top hat-shaped energy distribution in at least one orientation. By using laser light having a top-hat-like energy distribution, the cut surface of the polarizer protective film can be usually a steep surface that is nearly perpendicular to the main surface of the polarizer protective film. Moreover, when the laser beam which shows energy distribution of a top hat shape is used, normally the rise of the resin of the film in the vicinity of a cut surface can be suppressed.

The laser beam may be a continuous laser beam or a pulsed laser beam, but a pulsed laser beam is preferred from the viewpoint of cutting while suppressing the generation of heat.

When cutting, the laser beam is usually irradiated so that the irradiation point of the laser beam scans the surface of the polarizer protective film along a desired line. Thereby, a polarizer protective film can be cut | disconnected in the shape to cut | disconnect. At this time, in order to move the surface of the polarizer protective film to the irradiation point of the laser light, the laser light irradiation device may be moved, the polarizer protective film may be moved, and the irradiation device and the polarizer protection. Both of the films may be moved.

[8. Specific Embodiment of Display Device]
Hereinafter, more specific embodiments of the display device will be described, but the structure of the display device is not limited to the following embodiments.

FIG. 5 is a cross-sectional view schematically showing an example of a liquid crystal display device 50 as a display device according to an embodiment of the present invention.
As shown in FIG. 5, the liquid crystal display device 50 includes a light source 510; a light source side polarizer 520; a liquid crystal cell 530 as a display element; a retardation film 540; a viewing side polarizer 550; A polarizer protective film 570 including a base material 560 that can function as a / 4 plate is provided in this order. Moreover, in FIG. 5, the base material 560 is the 2nd base material layer 561 as a 1st optically anisotropic layer formed with the hardened | cured material of the liquid-crystal composition; First outer layer 562, The intermediate | middle layer containing a laser absorber. 563 and a first base material layer 565 having a second outer layer 564 in this order; and a conductive layer 566; are shown in this order from the viewing side polarizer 550 side. The structure is not limited to this example.

In the liquid crystal display device 50, a polarizer that is emitted from a light source 510 and includes a light source side polarizer 520, a liquid crystal cell 530, a retardation film 540, a viewing side polarizer 550, and a base material 560 that can function as a λ / 4 plate. An image is displayed by the light that has passed through the protective film 570. Since the optical compensation is performed by the retardation film 540, the liquid crystal display device 50 can obtain a sufficiently wide viewing angle. The light for displaying an image is linearly polarized when it passes through the viewing-side polarizer 550, but is converted into circularly polarized light by passing through the base material 560 of the polarizer protective film 570. Therefore, in the liquid crystal display device 50, an image is displayed by circularly polarized light. Therefore, when viewed through polarized sunglasses, the image can be visually recognized.

Further, in the liquid crystal display device 50, the conductive layer 566 can function as a circuit member such as an electrode for a touch panel and wiring. Therefore, it is possible to realize the liquid crystal display device 50 including a touch panel. Here, the touch panel is provided on the display device so that the user can input information by touching a predetermined location while referring to the image displayed on the display surface of the display device as necessary. Input device. Examples of the touch panel operation detection method include a resistance film method, an electromagnetic induction mode, and a capacitance method, and a capacitive touch panel is particularly preferable. In the example shown in FIG. 5, since the conductive layer 566 is provided at a position outside (viewing side) the viewing side polarizer 550 of the liquid crystal display device 50, an out-cell type touch panel can be obtained.

In the liquid crystal display device 50 described above, the polarizer protective film 570 has a base material 560 containing a laser absorber. Therefore, the liquid crystal display device 50 can be manufactured by a manufacturing method including a step of cutting the polarizer protective film 570 with a laser beam. Therefore, when the polarizer protective film 570 is cut, it is possible to suppress the generation of cutting residue and to smooth the cut surface, and thus it is possible to realize excellent display quality.

FIG. 6 is a cross-sectional view schematically showing an example of an organic EL display device 60 as a display device according to another embodiment of the present invention.
As shown in FIG. 6, the organic EL display device 60 includes an organic EL element 610 as a display element; a retardation film 620 having a predetermined in-plane retardation and functioning as a λ / 4 plate; a polarizer 630; And a polarizer protective film 650 including a base material 640 that includes a laser absorber and can function as a λ / 4 plate. In FIG. 6, the substrate 640 includes a first outer layer 641, an intermediate layer 642 containing a laser absorber, and a second outer layer 643 in this order; a second substrate layer 644; first outer layer 645, laser absorption An example in which an intermediate layer 646 containing an agent and a first base material layer 648 provided with a second outer layer 647 in this order; and a conductive layer 649; provided in this order from the polarizer 630 side are shown. The structure of the layer 640 is not limited to this example.

In the organic EL display device 60, only a part of the linearly polarized light passes through the polarizer 630 and passes through the retardation film 620, and becomes circularly polarized light. The circularly polarized light is reflected by a component (such as a reflective electrode (not shown) in the organic EL element 610) that reflects light in the display device, and passes through the retardation film 620 again, whereby incident linearly polarized light is reflected. The linearly polarized light has a vibration direction orthogonal to the vibration direction and does not pass through the polarizer 630. Thereby, an antireflection function is achieved (for the principle of antireflection in an organic EL display device, see Japanese Patent Application Laid-Open No. 9-127858).

Further, in the organic EL display device 60, the light was emitted from the organic EL element 610 and passed through the polarizer protective film 650 including the retardation film 620, the polarizer 630, and the base material 640 that can function as a λ / 4 plate. An image is displayed by light. The light for displaying an image is linearly polarized when it passes through the polarizer 630, but is converted into circularly polarized light by passing through the base material 640 of the polarizer protective film 650. Therefore, in the organic EL display device 60, an image is displayed by circularly polarized light. Therefore, when viewed through polarized sunglasses, the image can be visually recognized.

In the organic EL display device 60, the conductive layer 649 can function as a circuit member such as an electrode for a touch panel and wiring. Therefore, it is possible to realize the organic EL display device 60 including a touch panel.

In the organic EL display device 60 described above, the polarizer protective film 650 has a base material 640 containing a laser absorber. Therefore, since the organic EL display device 60 can be manufactured by a manufacturing method including a step of cutting the polarizer protective film 650 with laser light, the display quality is excellent as in the liquid crystal display device 50. Can be realized.

FIG. 7 is a cross-sectional view schematically showing an example of an organic EL display device 70 as a display device according to still another embodiment of the present invention.
As shown in FIG. 7, the organic EL display device 70 is provided in the same manner as the organic EL display device 60 shown in FIG. 6 except that a polarizer protective film 700 is provided instead of the polarizer protective film 650. . Specifically, the organic EL display device 70 shown in FIG. 7 includes an organic EL element 610 as a display element; a retardation film 620 that has a predetermined in-plane retardation and can function as a λ / 4 plate; and a polarizer 630. And a polarizer protective film 700 including a substrate 710 that includes a laser absorber and can function as a λ / 4 plate.

Moreover, the base material 710 includes a first outer layer 721, an intermediate layer 722 containing a laser absorber, and a second outer layer 723 in this order, a second base material layer 720; a first base material layer 730 containing a laser absorber; In addition, a conductive layer 740; is provided in this order from the polarizer 630 side. The second base material layer 720 preferably has a large in-plane retardation Re (550) as described in the first configuration example of the base material. Among them, the second base material layer 720 is a λ / 4 plate. It is particularly preferable to have in-plane retardation Re (550) that can function as Moreover, it is preferable that the 1st base material layer 730 has small in-plane retardation Re (550) as demonstrated in the 1st structural example of a base material, Especially, the said 1st base material layer 730 is optical etc. It is preferable to have an in-plane retardation Re (550) of 10 nm or less so that it can function as an isotropic layer. Such an organic EL display device 70 can obtain the same advantages as the organic EL display device 60 shown in FIG.

FIG. 8 is a cross-sectional view schematically showing an example of an organic EL display device 80 as a display device according to another embodiment of the present invention.
As shown in FIG. 8, the organic EL display device 80 is provided in the same manner as the organic EL display device 60 shown in FIG. 6 except that the polarizer protective film 800 is provided instead of the polarizer protective film 650. . Specifically, the organic EL display device 80 includes an organic EL element 610 as a display element; a retardation film 620 that has a predetermined in-plane retardation and can function as a λ / 4 plate; a polarizer 630; and a laser. A polarizer protective film 800 including a base material 810 that includes an absorber and can function as a λ / 4 plate.

Moreover, the base material 810 includes the third base material layer 850 containing a laser absorbent between the first base material layer 730 and the second base material layer 720, and the organic EL display shown in FIG. It is provided in the same manner as the base material 710 of the device 70. Specifically, the substrate 810 includes a first outer layer 721, an intermediate layer 722 including a laser absorber, and a second outer layer 723 in this order, a second substrate layer 720; a third substrate including a laser absorber. A layer 850; a first base material layer 730 containing a laser absorber; and a conductive layer 740; are provided in this order from the polarizer 630 side. In order to allow the third base material layer 850 to function as an optically isotropic layer, the third base material layer 850 is similar to the first base material layer described in the first configuration example of the base material. It is preferable to have an in-plane retardation Re (550) of 10 nm or less. Such an organic EL display device 80 can obtain the same advantages as the organic EL display device 60 shown in FIG.

FIG. 9 is a cross-sectional view schematically showing an example of an organic EL display device 90 as a display device according to another embodiment of the present invention.
As shown in FIG. 9, the organic EL display device 90 is provided in the same manner as the organic EL display device 60 shown in FIG. 6 except that a polarizer protective film 900 is provided instead of the polarizer protective film 650. . Specifically, the organic EL display device 90 includes an organic EL element 610 as a display element; a retardation film 620 that has a predetermined in-plane retardation and can function as a λ / 4 plate; a polarizer 630; and a laser. A polarizer protective film 900 including a base material 910 that includes an absorber and can function as a λ / 4 plate.

Moreover, the base material 910 includes the fourth base material layer 960 containing a laser absorbent on the opposite side of the second base material layer 720 from the first base material layer 730, and the organic EL shown in FIG. It is provided in the same manner as the base material 710 of the display device 70. Specifically, the substrate 910 includes a first outer layer 961, a middle layer 962 that may contain a laser absorber, and a second outer layer 963 in this order, a fourth substrate layer 960; a first outer layer 721. A second base material layer 720 comprising an intermediate layer 722 containing a laser absorber and a second outer layer 723 in this order; a first base material layer 730 containing a laser absorber; and a conductive layer 740; from the polarizer 630 side. Prepare in this order. Such an organic EL display device 90 can obtain the same advantages as the organic EL display device 60 shown in FIG. In particular, in the organic EL display device 90, the second base material layer 720 is configured so that the function as a broadband λ / 4 plate can be exhibited by the combination of the second base material layer 720 and the fourth base material layer 960. Can function as a λ / 4 plate, and the fourth base material layer 960 can function as a λ / 2 plate. At this time, the in-plane retardation of the second base material layer 720 and the fourth base material layer 960 and the crossing angle formed by the slow axis are the first base material layer 410 and the second base material in the second structural example of the base material. It can be the same as the material layer 420 (see FIG. 4).

Hereinafter, the present invention will be described in detail with reference to examples. However, the present invention is not limited to the following examples, and can be implemented with any modifications without departing from the scope of the claims of the present invention and the equivalents thereof.

In the following description, “%” and “part” representing the amount are based on weight unless otherwise specified. Further, the operations described below were performed in a normal temperature and pressure atmosphere unless otherwise specified.

[Measurement method of retardation]
The in-plane retardation was measured using a phase difference meter (“AxoScan” manufactured by Axometrics).

[Method for evaluating processability with laser light]
The circularly polarizing plate or polarizing plate produced in the examples or comparative examples was placed on a slider as an evaluation sample. A CO ₂ laser beam having a wavelength of 9.4 μm was applied to the surface of the evaluation sample on the side of the polarizer protective film. The output of the laser beam was adjusted so that a portion other than the glass plate of the evaluation sample could be cut. Specifically, the output of the laser beam is initially set to a low output and gradually increased. When the portion other than the glass plate of the evaluation sample can be cut or the glass plate is broken, the laser beam is irradiated. Stopped. After irradiation with laser light as described above, the evaluation sample was observed and evaluated according to the following criteria.
“A”: A portion other than the glass plate of the evaluation sample could be cut without damaging the glass plate, and the cut surface was flat and in a good cut state.
“B”: A portion other than the glass plate of the evaluation sample could be cut without damaging the glass plate. However, the cut surface of the polarizer included in the evaluation sample had irregularities or bulges in the resin due to heat melting.
“C”: The evaluation sample could not be cut, or the glass plate was broken.

[Durability evaluation method by heat cycle test of circularly polarizing plate and polarizing plate]
Using the circularly polarizing plate or the polarizing plate produced in the example or comparative example as an evaluation sample, a heat cycle test was conducted using a thermal shock device (“TSA-71L-A” manufactured by Espec). In this heat cycle test, a continuous operation of cooling at a temperature of −45 ° C. for 30 minutes and then heating at a temperature of 85 ° C. for 30 minutes was defined as one cycle, and 50 cycles of cooling and heating were performed. After this heat cycle test, the crack generation state over the entire length of the circularly polarizing plate or the polarizing plate as an evaluation sample was visually observed and evaluated according to the following criteria.
“A”: The polarizer forming the polarizing plate was not cracked or cracked at all.
“B”: The polarizer forming the polarizing plate had 20 or less cracks.
“C”: The polarizer forming the polarizing plate had 20 or more cracks.

[Production Example 1. Production of thermoplastic resin (J1)]
The pellets of thermoplastic resin (J0) as a norbornene polymer (manufactured by ZEON Corporation, glass transition temperature Tg = 126 ° C.) were dried at 100 ° C. for 5 hours. 100 parts of the dried pellets and 5.0 parts of a laser absorber (pentaerythritol tetrabenzoate, molecular weight 552, melting point 102.0 ° C. to 106.0 ° C.) were mixed by a twin screw extruder. The obtained mixture was put into a hopper connected to a single screw extruder and melt-extruded from the single screw extruder to obtain a thermoplastic resin (J1). The glass transition temperature Tg of this thermoplastic resin (J1) was 105 ° C.

[Production Example 2. Production of thermoplastic resin (J3)]
Instead of the thermoplastic resin (J0) used in Production Example 1, a thermoplastic resin (J2) as a norbornene polymer (manufactured by Nippon Zeon Co., Ltd., glass transition temperature Tg = 163 ° C.) was used. In addition to the laser absorber, 12.0 parts of a benzotriazole ultraviolet absorber (“LA-31” manufactured by ADEKA) was further added. Except for the above, a thermoplastic resin (J3) was obtained in the same manner as in Production Example 1. The glass transition temperature Tg of this thermoplastic resin (J3) was 126 ° C.

[Production Example 3. Production of λ / 4 plate (Q1)]
The thermoplastic resin (J3) produced in Production Example 2 was dried at 100 ° C. for 5 hours. The dried thermoplastic resin (J3) was supplied to an extruder and melted in the extruder. The molten thermoplastic resin (J3) was extruded through a polymer pipe and a polymer filter into a sheet form from a T die onto a casting drum. The extruded thermoplastic resin (J3) was cooled to obtain a pre-stretch base material (Q0) having a thickness of 145 μm and an in-plane retardation Re (550) of 8 nm. The obtained base material (Q0) before stretching was wound up to obtain a roll.

Next, the base material (Q0) before stretching was drawn from the roll of the base material (Q0) before stretching. The drawn base material (Q0) before stretching was supplied to a tenter stretching machine and subjected to an oblique stretching process to obtain a stretched film. The oblique stretching process refers to a stretching process in an oblique direction that is neither parallel nor perpendicular to the film width direction. In this oblique stretching process, the stretching ratio was 4.0 times, and the stretching temperature was 155 ° C. The obtained stretched film had an angle of 45 ° with respect to the width direction of the stretched film. The stretched film had an in-plane retardation Re (550) of 125 nm and a thickness of 36 μm. The obtained stretched film was wound up and collected as a λ / 4 plate (Q1).

[Production Example 4. Production of λ / 4 plate (Q3)]
A double flight type single screw extruder (screw diameter D = 50 mm, effective screw length L / screw diameter D ratio L / D = 28) equipped with a 3 μm leaf disk polymer filter did. Into this single screw extruder, the thermoplastic resin (J3) produced in Production Example 2 was introduced and melted as the resin for forming the intermediate layer. The molten thermoplastic resin (J3) was supplied to the single-layer die through the feed block under the conditions of an extruder outlet temperature of 260 ° C. and an extruder gear pump rotation speed of 10 rpm. The arithmetic average roughness Ra of the die slip of this single-layer die was 0.1 μm.

On the other hand, a single screw extruder (screw diameter D = 50 mm, effective screw length L / screw diameter D ratio L / D = 28) equipped with a leaf disk-shaped polymer filter with an opening of 3 μm was prepared. . Into this single screw extruder, a thermoplastic resin (J0) was introduced and melted as a thermoplastic resin for forming the first outer layer and the second outer layer. The molten thermoplastic resin (J0) was supplied to the single-layer die through a feed block under the conditions of an extruder outlet temperature of 285 ° C. and an extruder gear pump rotation speed of 4 rpm.

Next, the first outer layer forming resin layer, the intermediate layer forming resin layer, and the second outer layer forming resin layer are discharged into a film shape including three layers. The thermoplastic resins (J0) and (J3) were coextruded from the single layer die at 280 ° C. Then, the thermoplastic resins (J0) and (J3) discharged from the single-layer die were cast on a cooling roll whose temperature was adjusted to 150 ° C. to obtain a base material (Q2) before stretching having a thickness of 70 μm. This base material (Q2) before stretching comprises a first outer layer (thickness 17.5 μm) made of thermoplastic resin (J0) / an intermediate layer (thickness 35 μm) made of thermoplastic resin (J3) / thermoplastic resin (J0). It was the film which consists of 2 types 3 layers of the 2nd outer side layer (thickness 17.5 micrometers) which consists of. Here, 2 types and 3 layers represent the structure of a 3 layer film composed of 2 types of resins. The obtained base material before stretching (Q2) was wound up to obtain a roll.

Next, the base material (Q2) before stretching was pulled out from the roll of the base material (Q2) before stretching. The drawn base material (Q2) before stretching was supplied to a tenter stretching machine and subjected to an oblique stretching process to obtain a stretched film. In this oblique stretching process, the stretching ratio was 1.47 times, and the stretching temperature was 140 ° C. The obtained stretched film had an angle of 45 ° with respect to the width direction of the stretched film. The obliquely stretched film had an in-plane retardation Re (550) of 104 nm and a thickness of 48 μm. The stretched film obtained was wound up and collected as a λ / 4 plate (Q3).

[Production Example 5. Production of λ / 2 plate (H1)]
The thermoplastic resin (J0) used in Production Example 1 was dried at 100 ° C. for 5 hours. The dried thermoplastic resin (J0) was supplied to an extruder and melted in the extruder. The molten thermoplastic resin (J0) was extruded through a polymer pipe and a polymer filter into a sheet form from a T die onto a casting drum. The extruded thermoplastic resin (J0) was cooled to obtain a base material (H0) before stretching having a thickness of 70 μm. The obtained base material (H0) before stretching was wound up to obtain a roll.

Next, the base material (H0) before stretching was pulled out from the roll of the base material (H0) before stretching. The drawn base material (H0) before stretching was supplied to a tenter stretching machine and subjected to an oblique stretching process to obtain an intermediate film. In this oblique stretching process, the stretching ratio was 1.65 times, and the stretching temperature was 140 ° C. While the obtained intermediate film was continuously conveyed in the longitudinal direction, a longitudinal stretching process was performed to obtain a stretched film. The longitudinal stretching process refers to a stretching process in the longitudinal direction of the film. In this longitudinal stretching process, the stretching ratio was 1.45 times, and the stretching temperature was 135 ° C. The obtained stretched film had an angle of 75 ° with respect to the width direction of the stretched film. The stretched film had an in-plane retardation Re (550) of 245 nm and a thickness of 30 μm. The obtained stretched film was wound up and collected as a λ / 2 plate (H1).

[Production Example 6. Production of λ / 2 plate (H2)]
The base material (Q2) before stretching was drawn from the roll of the base material (Q2) before stretching obtained in Production Example 4. The drawn base material (Q2) before stretching was supplied to a tenter stretching machine and subjected to an oblique stretching process to obtain an intermediate film. In this oblique stretching process, the stretching ratio was 1.7 times, and the stretching temperature was 131 ° C. While the obtained intermediate film was continuously conveyed in the longitudinal direction, a longitudinal stretching process was performed to obtain a stretched film. In this longitudinal stretching process, the stretching ratio was 1.5 times, and the stretching temperature was 125 ° C. The obtained stretched film had an angle of 75 ° with respect to the width direction of the stretched film. The stretched film had an in-plane retardation Re (550) of 245 nm and a thickness of 27 μm. The obtained stretched film was wound up and collected as a λ / 2 plate (H2).

[Production Example 7. Production of λ / 2 plate (H3)]
A polymerizable liquid crystal compound represented by the following formula (A1) was prepared. This liquid crystal compound is a reverse wavelength dispersive liquid crystal compound. 21.25 parts of the liquid crystal compound represented by the formula (A1), 0.11 part of a surfactant (“Surflon S420” manufactured by AGC Seimi Chemical Co.), 0.64 part of a polymerization initiator (“IRGACURE379” manufactured by BASF) And 78.00 parts of a solvent (cyclopentanone, manufactured by Nippon Zeon Co., Ltd.) were mixed to prepare a liquid crystal composition A.

A λ / 2 plate (H1) as a stretched film obtained in Production Example 5 was prepared as a support. The support was fed from a roll and transported in the longitudinal direction at room temperature of 25 ° C. The liquid crystal composition A was directly applied on the transported support using a die coater to form a layer of the liquid crystal composition A. The layer of the liquid crystal composition A was subjected to an alignment treatment at 110 ° C. for 2.5 minutes. Then, under a nitrogen atmosphere (oxygen concentration of 0.1% or less), ultraviolet rays having an integrated light quantity of 1000 mJ / cm ² are irradiated to the side opposite to the layer of the liquid crystal composition A of the support, whereby the liquid crystal composition A The layer was irradiated. The layer of the liquid crystal composition A was cured by irradiation with ultraviolet rays, and an optically anisotropic layer having a dry film thickness of 4.4 μm was formed. This obtained the multilayer film provided with a support body and the optically anisotropic layer formed on the said support body. The optically anisotropic layer was a layer formed of a cured product of the liquid crystal composition A, and contained homogeneously aligned cured liquid crystal molecules. The angle formed by the slow axis of the optically anisotropic layer with respect to the width direction of the film was 75 °. The optically anisotropic layer had an in-plane retardation Re (550) of 240 nm and functioned as a λ / 2 plate. Therefore, this optically anisotropic layer was a λ / 2 plate (H3).

[Production Example 8. Production of λ / 4 plate (Q4)]
A commercially available obliquely stretched film made of an alicyclic structure-containing polymer (the angle formed by the slow axis with respect to the width direction is 45 °, the thickness is 60 μm, and the in-plane retardation Re (550) is 141 nm) was prepared. This commercially available diagonally stretched film was used as a support instead of the λ / 2 plate (H1) used in Production Example 7. Further, the thickness of the liquid crystal composition A layer formed on the support was changed so that an optically anisotropic layer having a dry film thickness of 2.2 μm was obtained. Except for the above, a multilayer film including a support and an optically anisotropic layer formed on the support was obtained in the same manner as in Production Example 7. The optically anisotropic layer was a layer formed of a cured product of the liquid crystal composition A, and contained homogeneously aligned cured liquid crystal molecules. The angle formed by the slow axis of the optically anisotropic layer with respect to the width direction of the film was 45 °. The optically anisotropic layer had an in-plane retardation Re (550) of 139 nm and functioned as a λ / 4 plate. In addition, Re (450) / Re (550) of the optically anisotropic layer was 0.83. Therefore, this optically anisotropic layer was a λ / 4 plate (Q4).

[Production Example 9. Production of λ / 4 plate (Q6)]
As a thermoplastic resin for forming the first outer layer and the second outer layer, a thermoplastic resin (J2) was used instead of the thermoplastic resin (J0). Except for the above, a substrate before stretching (Q5) having a thickness of 70 μm was obtained in the same manner as in the method for producing a substrate before stretching (Q2) in Production Example 4. This base material (Q5) before stretching is composed of a first outer layer (thickness 17.5 μm) made of thermoplastic resin (J2) / an intermediate layer (thickness 35 μm) made of thermoplastic resin (J3) / thermoplastic resin (J2). It was the film which consists of 2 types and 3 layers of the 2nd outer side layer (thickness 17.5 micrometers) which consists of. The obtained base material before stretching (Q5) was wound up to obtain a roll.

Next, the base material (Q5) before stretching was drawn from the roll of the base material (Q5) before stretching. The drawn base material (Q5) before stretching was supplied to a tenter stretching machine and subjected to an oblique stretching process to obtain a stretched film. In this oblique stretching process, the stretching ratio was 2.0 times, and the stretching temperature was 180 ° C. The obtained stretched film had an angle of 45 ° with respect to the width direction of the stretched film. The obliquely stretched film had an in-plane retardation Re (550) of 130 nm and a thickness of 35 μm. The stretched film obtained was wound up and collected as a λ / 4 plate (Q6).

[Example 1]
A λ / 4 plate (Q1) manufactured in Production Example 3 was prepared as a polarizer protective film. This polarizer protective film, adhesive (“CS9621T” manufactured by Nitto Denko Corporation), polarizer (“HLC2-5618S” manufactured by Sanlitz Co., Ltd., thickness 180 μm, having a transmission axis in the direction of 0 ° with respect to the width direction), A pressure-sensitive adhesive (“CS9621T” manufactured by Nitto Denko Corporation) and a glass plate (thickness 0.7 mm) were laminated in this order to produce a circularly polarizing plate (P1). In the obtained circularly polarizing plate (P1), the crossing angle between the slow axis of the λ / 4 plate (Q1) and the transmission axis of the polarizer was 45 °. As a result of evaluating the workability of this circularly polarizing plate (P1) by laser light, it was “A” standard. Moreover, as a result of evaluating durability by a heat cycle test, it was “A” standard.

[Example 2]
As the polarizer protective film, the λ / 4 plate (Q3) produced in Production Example 4 was used instead of the λ / 4 plate (Q1) used in Example 1. Except for the above, a circularly polarizing plate (P2) was produced in the same manner as in Example 1. In the obtained circularly polarizing plate (P2), the crossing angle between the slow axis of the λ / 4 plate (Q3) and the transmission axis of the polarizer was 45 °. As a result of evaluating the workability of this circularly polarizing plate (P2) by laser light, it was “B” standard. Moreover, as a result of evaluating durability by a heat cycle test, it was a “B” standard.

[Example 3]
The base material before stretching (Q0) having optical isotropy obtained in Production Example 3 and the λ / 4 plate (Q1) obtained in Production Example 3 were passed through an adhesive (“CS9621T” manufactured by Nitto Denko Corporation). And laminated to obtain a laminate. This laminate was used as a polarizer protective film instead of the λ / 4 plate (Q1) used in Example 1. Except for the above, a circularly polarizing plate (P3) was produced in the same manner as in Example 1. In the obtained circularly polarizing plate (P3), the crossing angle between the slow axis of the λ / 4 plate (Q1) of the laminate and the transmission axis of the polarizer was 45 °. As a result of evaluating the workability of this circularly polarizing plate (P3) by laser light, it was “A” standard. Moreover, as a result of evaluating durability by a heat cycle test, it was “A” standard.

[Example 4]
The λ / 4 plate (Q1) obtained in Production Example 3 and the λ / 2 plate (H1) obtained in Production Example 5 were bonded via an adhesive (“CS9621T” manufactured by Nitto Denko Corporation), and the broadband A λ / 4 plate was obtained. This broadband λ / 4 plate was used as a polarizer protective film instead of the λ / 4 plate (Q1) used in Example 1. A circularly polarizing plate (P4) was produced in the same manner as in Example 1 except for the above items. In the obtained circularly polarizing plate (P4), the crossing angle between the slow axis of the λ / 4 plate (Q1) of the broadband λ / 4 plate and the slow axis of the λ / 2 plate (H1) was 60 °. . The crossing angle between the slow axis of the λ / 2 plate (H1) and the transmission axis of the polarizer was 15 °. As a result of evaluating the workability of this circularly polarizing plate (P4) by laser light, it was “A” standard. Moreover, as a result of evaluating durability by a heat cycle test, it was “A” standard.

[Example 5]
The λ / 4 plate (Q1) obtained in Production Example 3 and the λ / 2 plate (H2) obtained in Production Example 6 were bonded together via an adhesive (“CS9621T” manufactured by Nitto Denko Corporation) A λ / 4 plate was obtained. This broadband λ / 4 plate was used as a polarizer protective film instead of the λ / 4 plate (Q1) used in Example 1. A circularly polarizing plate (P5) was produced in the same manner as in Example 1 except for the above items. In the obtained circularly polarizing plate (P5), the crossing angle between the slow axis of the λ / 4 plate (Q1) of the broadband λ / 4 plate and the slow axis of the λ / 2 plate (H2) was 60 °. . The crossing angle between the slow axis of the λ / 2 plate (H2) and the transmission axis of the polarizer was 15 °. As a result of evaluating the workability of this circularly polarizing plate (P5) by laser light, it was “A” standard. Moreover, as a result of evaluating durability by a heat cycle test, it was “A” standard.

[Example 6]
The λ / 4 plate (Q1) obtained in Production Example 3 and the λ / 2 plate (H3) as the optically anisotropic layer of the multilayer film obtained in Production Example 7 were combined with an adhesive (manufactured by Nitto Denko Corporation “ CS9621T "). Thereafter, the multilayer film support was peeled off to obtain a broadband λ / 4 plate comprising a λ / 4 plate (Q1), an adhesive and a λ / 2 plate (H3) in this order. This broadband λ / 4 plate was used as a polarizer protective film instead of the λ / 4 plate (Q1) used in Example 1. Except for the above, a circularly polarizing plate (P6) was produced in the same manner as in Example 1. In the obtained circularly polarizing plate (P6), the crossing angle of the slow axis of the λ / 4 plate (Q1) of the broadband λ / 4 plate and the slow axis of the λ / 2 plate (H3) was 60 °. The crossing angle between the slow axis of the λ / 2 plate (H3) and the transmission axis of the polarizer was 15 °. As a result of evaluating the workability of this circularly polarizing plate (P6) by laser light, it was “A” standard. Moreover, as a result of evaluating durability by a heat cycle test, it was “A” standard.

[Example 7]
Instead of the λ / 4 plate (Q1) used in Example 1, the λ / 4 plate (Q6) manufactured in Production Example 9 was used as the polarizer protective film. Except for the above, a circularly polarizing plate (P7) was produced in the same manner as in Example 1. In the obtained circularly polarizing plate (P7), the crossing angle between the slow axis of the λ / 4 plate (Q6) and the transmission axis of the polarizer was 45 °. As a result of evaluating the workability of this circularly polarizing plate (P7) by laser light, it was “B” standard. Moreover, as a result of evaluating durability by a heat cycle test, it was “A” standard.

[Comparative Example 1]
As a polarizer protective film, instead of the λ / 4 plate (Q1) used in Example 1, a film before stretching (Zeonor film ZF14-100, manufactured by Nippon Zeon Co., Ltd., thickness 100 μm, resin Glass transition temperature 136 ° C.) was used. This pre-stretch film was an optically isotropic film made of a resin containing an alicyclic structure-containing polymer. A polarizing plate (P7) was produced in the same manner as in Example 1 except for the above items. As a result of evaluating the workability of this polarizing plate (P7) by laser light, it was “C” standard. Moreover, as a result of evaluating durability by a heat cycle test, it was “C” standard.

[Comparative Example 2]
As a polarizer protective film, instead of the λ / 4 plate (Q1) used in Example 1, an obliquely stretched film containing no laser absorber (“obliquely stretched phase difference film” manufactured by Nippon Zeon Co., Ltd., thickness 47 μm, in-plane The retardation Re (550) was 125 nm, and the angle formed by the slow axis with respect to the width direction of the film was 45 °. This obliquely stretched film was a commercially available film made of a resin containing an alicyclic structure-containing polymer. A circularly polarizing plate (P8) was produced in the same manner as in Example 1 except for the above items. As a result of evaluating the workability of this circularly polarizing plate (P8) by laser light, it was “C” standard. Moreover, as a result of evaluating durability by a heat cycle test, it was “C” standard.

[Example 8]
The λ produced in Production Example 4 via an adhesive (“CS9621T” manufactured by Nitto Denko Corporation) on the surface opposite to the λ / 4 plate (Q1) of the circularly polarizing plate (P1) produced in Example 1 / 4 plate (Q3) was bonded as a retardation film. Thereby, the visual recognition side member (T1) provided with a polarizer protective film, an adhesive, a polarizer, an adhesive, a glass plate, an adhesive, and a retardation film in this order was manufactured. In the obtained viewing side member (T1), the crossing angle between the transmission axis of the polarizer and the slow axis of the retardation film was 45 °.

(Manufacture of image display devices)
Two commercially available liquid crystal display devices (“iPad” (registered trademark) manufactured by Apple) equipped with a viewing side polarizing plate, a liquid crystal cell, a light source side polarizing plate, and a light source in this order were prepared.
The display surface part of one liquid crystal display device was disassembled, the viewing side polarizing plate of the liquid crystal display device was peeled off, and a viewing side member (T1) was attached instead. The viewing side member (T1) was attached so that the polarizer protective film was directed to the viewing side. Thereby, the viewing side member (T1), the liquid crystal cell as an image display element, the light source side polarizing plate, and the light source were obtained in this order from the viewing side.

(Naked eye observation)
About one liquid crystal display device which attached the visual recognition side member (T1), the color and the brightness of the display screen were visually observed with the naked eye. Moreover, about the other liquid crystal display device which has not attached the visual recognition side member (T1), the color and brightness | luminance of the display screen were visually observed with the naked eye. The above observation was performed in the front direction of the display screen. As a result, the difference between the two liquid crystal display devices was hardly discernable.

(Observation of polarized sunglasses)
About one liquid crystal display device which attached the visual recognition side member (T1), the polarized sunglasses were put on and the display screen was observed. Moreover, about the other liquid crystal display device which has not attached the visual recognition side member (T1), polarized sunglasses were mounted | worn and the display screen was observed. The above observation was performed in the tilt direction of the display screen. The inclination direction of a surface represents a direction that is neither parallel nor perpendicular to the surface. As a result, in one liquid crystal display device to which the viewing side member (T1) was attached, its brightness hardly changed even in the tilt direction compared to the front direction of the display screen. On the other hand, in the other liquid crystal display device to which the visual recognition side member (T1) is not attached, the brightness changes in the inclination direction and becomes darker than the front direction of the display screen.

[Example 9]
The λ produced in Production Example 8 via an adhesive (“CS9621T” manufactured by Nitto Denko Corporation) on the surface opposite to the λ / 4 plate (Q1) of the circularly polarizing plate (P1) produced in Example 1 / 4 plate (Q4) was bonded as a retardation film. Thereby, the visual recognition side member (T2) provided with a polarizer protective film, an adhesive, a polarizer, an adhesive, a glass plate, an adhesive, and a retardation film in this order was manufactured. In the obtained viewing side member (T2), the crossing angle between the transmission axis of the polarizer and the slow axis of the retardation film was 45 °.

(Manufacture of image display devices)
A commercially available OLED smartphone ("G Flex LGL23" manufactured by LG Electronics) having a viewing-side polarizing plate and an organic EL display element in this order was prepared.
The viewing side polarizing plate of this smartphone was peeled off, and a viewing side member (T2) was attached instead. The viewing side member (T2) was attached so that the polarizer protective film was directed to the viewing side. Thereby, an organic EL display device including a circularly polarizing plate was obtained. The luminance of the organic EL display device during black display and white display was 6.2 cd / m ² and 305 cd / m ² , respectively.

The display screen was viewed from the front direction in a state where the organic EL display device was displayed in black under the daylight on a sunny day. As a result, there was no reflection of external light on the display screen, and the display screen was black. Furthermore, when the display screen was visually observed from an oblique direction (polar angle 45 °, omnidirectional), changes in reflectance and color due to the azimuth were not observed.

DESCRIPTION OF SYMBOLS 10 Display apparatus 50 Liquid crystal display apparatus 60 Organic EL display apparatus 110 Polarizer protective film 111 Base material 120 Polarizer 130 Phase difference film 140 Display element 200 Resin layer 210 1st outer side layer 220 2nd outer side layer 230 Intermediate layer 300 Base material 310 First base material layer 320 Second base material layer 330 Conductive layer 400 Base material 410 First base material layer 420 Second base material layer 430 Conductive layer 510 Light source 520 Light source side polarizer 530 Liquid crystal cell 540 Phase difference film 550 Viewing side polarization Child 560 Base material 561 Second base material layer 562 First outer layer 563 Intermediate layer 564 Second outer layer 565 First base material layer 566 Conductive layer 570 Polarizer protective film 610 Organic EL element 620 Retardation film 630 Polarizer 640 Base Material 641 First outer layer 642 Intermediate layer 643 Second outer layer 644 Second substrate 645 first outer layer 646 intermediate layer 647 second outer layer 648 polarizer protective film first substrate layer 649 conductive layer 650

Claims

A display device comprising a polarizer protective film, a polarizer, a retardation film and a display element in this order,
The polarizer protective film contains a laser absorber and a substrate that can function as a λ / 4 plate,
The display device, wherein the retardation film has an in-plane retardation Re (550) at a wavelength of 550 nm of 90 nm to 150 nm.
The base material has a first base material layer having an in-plane retardation Re (550) of 10 nm or less at a wavelength of 550 nm, and a second base material layer having an in-plane retardation Re (550) of 90 nm to 150 nm at a wavelength of 550 nm. And a conductive layer formed on at least one surface of the first base material layer,
The display device according to claim 1, wherein the laser absorbent is included in one or both of the first base material layer and the second base material layer.
The base material is a first base material layer that can function as a λ / 4 plate, a second base material layer that can function as a λ / 2 plate, and a conductive layer formed on at least one surface of the first base material layer. And can function as a broadband λ / 4 plate,
The display device according to claim 1, wherein the laser absorbent is included in one or both of the first base material layer and the second base material layer.
The display device according to claim 3, wherein the second base material layer is formed of a cured product of a liquid crystal composition containing a liquid crystal compound.
One or both of the first substrate layer and the second substrate layer are
A first outer layer;
A second outer layer;
The display device according to claim 2, further comprising an intermediate layer provided between the first outer layer and the second outer layer.
The display device according to claim 5, wherein the intermediate layer includes an ultraviolet absorber.
Wherein the first outer layer is formed by a first outer resin having a glass transition temperature Tg O1,
The second outer layer is formed with a second outer resin having a glass transition temperature Tg O2,
The intermediate layer is formed of an intermediate resin having a glass transition temperature Tg C ;
The glass transition temperature Tg O1 of the first outer resin is lower than the glass transition temperature Tg C of the intermediate resin,
The second glass transition temperature Tg O2 of the outer resin, the lower the glass transition temperature Tg C of the intermediate resin, the display device according to claim 5 or 6, wherein.
The difference Tg C −Tg O1 between the glass transition temperature Tg O1 of the first outer resin and the glass transition temperature Tg C of the intermediate resin is 30 ° C. or more,
The display device according to claim 7, wherein a difference Tg C −Tg O 2 between the glass transition temperature Tg O 2 of the second outer resin and the glass transition temperature Tg C of the intermediate resin is 30 ° C. or more.
The display device according to any one of claims 2 to 8, wherein a thickness of one or both of the first base material layer and the second base material layer is 10 袖 m to 60 袖 m.
10. The display device according to claim 1, wherein a slow axis of the base material and a transmission axis of the polarizer intersect.
The display device according to claim 10, wherein the crossing angle between the slow axis of the substrate and the transmission axis of the polarizer is 45 ° ± 5 °.
The display device according to any one of claims 1 to 11, wherein the base material includes a crystalline polymer.
The display device according to any one of claims 1 to 12, wherein the base material and the retardation film each contain an alicyclic structure-containing polymer.
The display device according to any one of claims 1 to 13, wherein the base material and the retardation film each include a stretched film.
The retardation film is formed of a cured product of a liquid crystal composition containing a liquid crystal compound,
The in-plane retardation Re (450) of the retardation film at a wavelength of 450 nm and the in-plane retardation Re (550) of the retardation film at a wavelength of 550 nm are Re (450) / Re (550) <1.0. The display device according to any one of claims 1 to 12, which satisfies:
The display device according to any one of claims 1 to 15, wherein the display element is a liquid crystal cell.
The display device according to any one of claims 1 to 15, wherein the display element is an organic electroluminescence element.