KR20200014225A - Circular polarizer and display device - Google Patents

Abstract

When a circular polarizing plate provided in an endurance test for a high temperature and high humidity environment is left at the room temperature, a problem that the in-plane uniformity of a reflected color deteriorates over time is improved. As the circular polarizing plate in which a polarizing plate and a retardation film are laminated, the polarizing plate provides a polarizer and a protective film. Provided is the circular polarizing plate, in which the protective film is disposed on an opposite side to a retardation film side in the polarizer, the moisture permeability of the protective film is 450 g / m^2 · 24 hours or less, and a dimensional shrinkage rate of the circular polarizing plate is 4.1 × 10-4 mm / hour or less.

Description

Circular polarizer and display device {CIRCULAR POLARIZER AND DISPLAY DEVICE}

The present invention relates to a circular polarizing plate and a display device.

In recent years, image display apparatuses typified by organic electroluminescent (hereinafter, also referred to as organic EL) display devices are rapidly spreading. The circularly polarizing plate provided with a polarizer and retardation film ((lambda) / 4 board) is mounted in an organic electroluminescence display. By disposing the circular polarizing plate, reflection of external light can be prevented, and the visibility of the screen can be improved.

With the rise of the organic EL display device, as the demand for thinning the image display device becomes stronger, the thickness of the circular polarizing plate is also required. From the retardation film which shape | molded the conventional resin film, changing into the retardation film formed from the liquid crystal compound which can be thinned as a material is examined (for example, refer patent document 1). The retardation film using a polymerizable liquid crystal compound is manufactured by coating and aligning a polymeric liquid crystal compound on a base material, performing light irradiation as needed, and fixing an orientation state.

When the circularly polarizing plate provided for the durability test for a high temperature, high humidity environment was left at room temperature, there existed a problem that the in-plane uniformity of a reflection color deteriorated with time. Specifically, when the circular polarizing plate was rectangular, there was a problem that the reflection colors near the four short sides of the circular polarizing plate changed to blue or red, respectively.

[Patent Document 1] Japanese Patent Application Publication No. 2017-54093

An object of the present invention is to provide a circularly polarizing plate having a small change in reflection color even when placed in a high temperature, high humidity environment and then placed in a room temperature environment.

[1] A circularly polarizing plate in which a polarizing plate and a retardation film are laminated, wherein the polarizing plate includes a polarizer and a protective film, and the protective film is disposed on the side opposite to the retardation film side in the polarizer, and the moisture permeability of the protective film. Is 450 g / m 2 · 24 hours (hr.) Or less, and the dimensional shrinkage rate of the circular polarizing plate is 4.1 × 10 ⁻⁴ mm / hr. Circular polarizing plate which is below.

[2] The shape of the main surface is substantially rectangular, and the slow axis of the retardation film is parallel to the long side direction of the circular polarizing plate, and the slow axis of the retardation film and the absorption axis of the polarizer. The circularly polarizing plate as described in [1] whose magnitude | size of this angle is about 45 degrees.

[3] The circularly polarizing plate according to [1] or [2], in which the retardation film includes a layer on which a polymerizable liquid crystal compound is cured, and an adhesive layer is disposed on the side opposite to the polarizing plate side in the retardation film. .

[4] The circularly polarizing plate according to any one of [1] to [3], further comprising a display panel.

[5] The circularly polarizing plate according to [4], which is bendable.

[6] The circular polarizing plate according to [4] or [5], further comprising a touch sensor and a window film, wherein the display panel, the touch sensor, the polarizer, and the window film are laminated in this order.

[7] The circularly polarizing plate according to [4] or [5], further comprising a touch sensor, wherein the display panel, the polarizer, and the touch sensor are laminated in this order.

[8] The circularly polarizing plate according to [7], further comprising a window film, wherein a display panel, a polarizer, a touch sensor, and a window film are laminated in this order.

[9] A display device in which the circularly polarizing plate according to any one of [1] to [8] is laminated on a display element via the pressure-sensitive adhesive layer.

According to the present invention, even after being placed in a high temperature, high humidity environment, a circularly polarizing plate having a small change in reflection color can be provided.

1 is an example of schematic sectional drawing which shows the laminated constitution of a circularly polarizing plate.
2 is a top view of a sample for evaluation.

Circular Polarizing Plate

The circular polarizing plate of the present invention includes a polarizing plate and a retardation film. The polarizing plate and the retardation film can be laminated through, for example, an adhesive layer. As an adhesive layer, the adhesive layer and adhesive bond layer mentioned later are mentioned, for example. Examples of the adhesive layer include an aqueous adhesive layer and an activated energy ray curable adhesive layer. In this invention, a polarizing plate means the laminated body which consists of a polarizer and the protective film bonded to the single side | surface or both surfaces of a polarizer.

Hereinafter, with reference to FIG. 1, an example of the laminated constitution of the circularly polarizing plate of this invention is demonstrated. In addition, in FIG. 1, the adhesive bond layer for bonding the polarizer 10, the protective film 11, and the protective film 12, respectively is not shown. In the circular polarizing plate 100 illustrated in FIG. 1A, the first protective film 11 is laminated on one surface of the polarizer 10, and the second protective film () is formed on the other surface of the polarizer 10. The retardation film 2 containing the polarizing plate 1 in which 12) was laminated | stacked, and the layer 20 in which the polymeric liquid crystal compound was hardened | cured has the laminated constitution laminated | stacked through the adhesive layer 13. As shown in FIG. In addition, the circular polarizing plate 100 has the adhesive layer 14 in the surface on the opposite side to the polarizing plate 1 in the retardation film 2. The pressure-sensitive adhesive layer 14 may be a pressure-sensitive adhesive layer for bonding to an organic EL display element or the like. In FIG.1 (a), both the protective film 11 and the protective film 12 may exist in the range which the water vapor transmission rate of a protective film mentions later, and may exist in the range which a water vapor transmission rate of only one protective film mentions later. It is preferable that the circularly polarizing plate of this invention shows the water vapor transmission rate in the range which the protective film laminated | stacked on the surface of the polarizer's visual recognition side mentions later.

In the circular polarizing plate 101 illustrated in FIG. 1B, the first protective film 11 is laminated on one surface of the polarizer 10, and the second protective film () is formed on the other surface of the polarizer 10. The polarizing plate 1 in which 12) was laminated | stacked, and the retardation film 2 have the laminated constitution laminated | stacked through the adhesive layer 13. In the circular polarizing plate 101, the retardation film 2 is a layer structure in which the layer 20 on which the polymerizable liquid crystal compound is cured and the layer 21 on which the polymerizable liquid crystal compound is cured are laminated through the adhesive layer 15. Has Moreover, the circular polarizing plate 101 has the adhesive layer 14 in the surface on the opposite side to the polarizing plate 1 in the retardation film 2. The pressure-sensitive adhesive layer 14 may be a pressure-sensitive adhesive layer for bonding to an organic EL display element or the like. The circular polarizing plate of this invention may have the laminated constitution in which the protective film was laminated | stacked on one surface of the polarizer, and the retardation film was laminated | stacked on the other surface of the polarizer. A polarizer and a protective film can be laminated | stacked through an adhesive layer as mentioned above. In addition, a polarizer and retardation film can be laminated | stacked through an adhesive layer.

As shown in FIG. 1, the retardation film may have one layer or two layers. In addition, the retardation film may have the orientation film for orientating a polymeric liquid crystal compound in the manufacturing step.

The circular polarizer may have layers other than the layer shown in FIG. 1. As a layer which the circularly polarizing plate may further have, a front plate, a light shielding pattern, etc. are mentioned. The front plate may be arranged on the side opposite to the side on which the retardation film in the polarizing plate is laminated. As a front plate, glass, a touch sensor, a window film, etc. are mentioned. The window film usually includes a hard coat layer on at least one surface of the transparent substrate. The touch sensor is a member formed by stacking an insulating layer, an electrode layer, and a base material. The electrode layer has a sensing pattern formed of a transparent electrode and a bridge electrode, and a sensing line. The transparent electrode, the bridge electrode, and the sensing line can be produced by known materials and methods. The insulating layer and base material in a touch sensor can be produced by a well-known method. The display panel may be a bendable display panel. CLAIMS 1. A circular polarizing plate comprising: a circular polarizing plate further comprising a display panel (eg, a bendable display panel); A circular polarizer further comprising a display panel (eg, a bendable display panel), a touch sensor, and a window film, wherein the display panel, the touch sensor, the polarizer, and the window film are stacked in this order; A circular polarizer further comprising a display panel (eg, a bendable display panel) and a touch sensor, wherein the display panel, the polarizer, and the touch sensor are stacked in this order; A circular polarizer further comprising a display panel (eg, a bendable display panel) and a window film, wherein the display panel, the polarizer, the touch sensor, and the window film are stacked in this order; Etc. can be mentioned.

The light shielding pattern can be formed on the surface on the polarizing plate side in the front plate. The light shielding pattern is formed in a frame (non-display area) of the image display device, and can prevent the wiring of the image display device from being visually recognized by the user.

The shape of the main surface of the circular polarizing plate may be substantially rectangular. The main surface means the surface having the largest area corresponding to the display surface. Substantially a rectangle is a shape in which at least one of four corners (edges) is cut off to form an obtuse angle or a rounded shape, or a recess (cutout) in which a part of the main surface is recessed in the in-plane direction, or a round or oval shape. Or a perforated portion cut out into a shape such as a polygon, a combination thereof, or the like.

The size of the circular polarizing plate is not particularly limited. When the circular polarizing plate is substantially rectangular, the length of the long side is preferably 6 cm or more and 35 cm or less, more preferably 10 cm or more and 30 cm or less, and the length of the short side is preferably 5 cm or more and 30 cm or less, and 6 cm It is more preferable that it is 25 cm or more.

In the circular polarizing plate of the present invention, the angle between the slow axis of the retardation film and the absorption axis of the polarizer is preferably about 45 °. About 45 degrees means 45 +/- 10 degrees.

When the shape of the circular polarizing plate is substantially rectangular, the slow axis of the retardation film may be parallel to the long side direction or the short side direction, and the magnitude of the angle formed between the slow axis of the retardation film and the absorption axis of the polarizer is approximately 45 degrees. It may be °. In the case of such an axial structure, the effect of this invention is remarkable.

The circularly polarizing plate had a dimensional shrinkage rate of 4.1 × 10 ⁻⁴ mm / hr. It is as follows. The dimensional shrinkage rate of the circularly polarizing plate was 4.0 × 10 ⁻⁴ mm / hr. It is preferable that it is the following. By setting it as such a relatively slow range of dimensional change behavior, since stress relaxation applied to a retardation film occurs in parallel with shrinkage of a circularly polarizing plate, it is guessed that the change of a phase difference value can be suppressed.

By examination of the present inventors, it became clear that the change of the reflection color of a circularly polarizing plate is caused by the change of the phase difference value of a retardation film. In addition, it became clear that the change of the retardation value of the retardation film was caused by the dimensional change of the circularly polarizing plate caused by the ingress and ingress of moisture. By setting the dimensional shrinkage rate of the circularly polarizing plate in such a range, it is possible to reduce the dimensional change (specifically, shrinkage due to the release of water) due to the inflow and outflow of moisture when the transition from the high temperature and high humidity environment to the room temperature environment occurs. . As a result, it is thought that the stress which arises in the edge part of a circularly polarizing plate can be reduced, and the change of a phase difference value can be made small. The dimensional shrinkage rate of the circular polarizing plate was 0.5 × 10 ⁻⁴ mm / hr. Ideally, it may be 1.0 × 10 ⁻⁴ mm / hr. The above may be sufficient. By making the dimensional shrinkage rate of a circular polarizing plate into this range, the external appearance defect resulting from shifting of the adhesive on the display element side can also be suppressed.

The dimensional shrinkage rate of the circular polarizing plate can be measured as follows. The circularly polarizing plate is cut out to a size of 50 mm in the slow axis direction of the retardation film and 50 mm in the fast axis direction of the retardation film. The cut circular polarizing plate is bonded to an alkali-free glass (manufactured by Corning, product name: Eagle XG) having a thickness of 0.4 mm, and placed in an oven of a high-temperature, high-humidity environment (60 ° C, 95% relative humidity) for 168 hours. Immediately after taking out from an oven in a room temperature environment (temperature 23 degreeC, relative humidity 55%), the dimension of a circularly polarizing plate is measured, and also the dimension of the circularly polarizing plate at the time of storing for 24 hours in a room temperature environment is measured. The dimensional shrinkage rate of the circularly polarizing plate is calculated from the slope of the dimensional change. In addition, in each measurement mentioned above, the dimension of the slow-axis direction of retardation film is measured.

The dimensional shrinkage rate of the circular polarizing plate can be controlled as follows. Control of the dimensional shrinkage rate of the circularly polarizing plate can be controlled by controlling the rate of moisture evaporation from the polarizer having the highest amount of moisture. For example, control of a dimensional shrinkage rate is possible by adjusting the moisture permeability of the protective film of a polarizer and the thickness of a polarizer. As described later, as the moisture permeability of the protective film of the polarizer is lower, the shrinkage of the polarizing plate is suppressed, and as a result, the dimensional shrinkage rate of the circular polarizing plate tends to be smaller. The smaller the thickness of the polarizer, the smaller the entrance and exit of moisture from the polarizer, and therefore, the dimensional shrinkage rate of the circular polarizing plate tends to be smaller.

It is preferable that it is 0.25% or less, as for the dimensional shrinkage rate of a circular polarizing plate in the fast axis direction of a retardation film, It is more preferable that it is 0.20% or less, It is further more preferable that it is 0.15% or less. When the rate of dimensional change satisfies this range, the change in the reflection color is further reduced. Although a lower limit is not specifically limited, 0.0% or more may be sufficient as the dimensional shrinkage rate of a circular polarizing plate in the fast-axis direction of a retardation film.

It is preferable that it is 0.15% or less in a retardation film slow axis direction, as for the dimensional shrinkage rate of a circular polarizing plate, It is more preferable that it is 0.10% or less, It is further more preferable that it is 0.08% or less. When the rate of dimensional change satisfies this range, the change in the reflection color is further reduced. Although a lower limit is not specifically limited, 0.0% or more of the dimensional shrinkage rate of a circularly polarizing plate may be sufficient in the retardation film slow axis direction.

The dimensional shrinkage rate of the circular polarizing plate can be measured as follows. The circularly polarizing plate is cut out to a size of 50 mm in the slow axis direction of the retardation film and 50 mm in the fast axis direction of the retardation film. The cut circular polarizing plate is bonded to an alkali free glass (manufactured by Corning, product name: Eagle XG) having a thickness of 0.4 mm, and placed in an oven of a high temperature and high humidity environment (temperature 60 ° C, relative humidity 95%) for 168 hr. Using a two-dimensional dimensional measuring device (device name: VMR-12072 manufactured by Nikon), the dimensions of the circularly polarizing plate (initial size) and the circularly polarizing plate immediately after taking this out of the oven were measured using a two-dimensional formula. The dimensional shrinkage rate of the polarizing plate is calculated.

Dimensional shrinkage rate (%) of circular polarizing plate = (initial dimension-dimensions after heating) / initial dimension * 100

The dimensional shrinkage rate of the circular polarizing plate can be controlled as follows. The control of the dimensional shrinkage ratio of the polarizing plate is first performed by suppressing the shrinking force of the polarizer, and secondly by selecting the protective film of the polarizer having a low water vapor permeability and hardly shrinkage expansion by water.

<Polarizing plate>

In this invention, a polarizing plate means the laminated body which consists of a polarizer and the protective film bonded to the single side | surface or both surfaces of a polarizer. The protective film with which a polarizing plate is equipped may have surface treatment layers, such as a hard-coat layer mentioned later, an antireflection layer, an antistatic layer, and the like. A polarizer and a protective film can be laminated | stacked through an adhesive bond layer or an adhesive layer, for example. The member with which a polarizing plate is equipped is demonstrated below.

(1) polarizer

It is preferable that the contraction force of the polarizer in this invention is 3.0 N or less in 80 degreeC environment. The shrinkage force here is the contraction force in the absorption axis direction of a polarizer, and refers to the contraction force per 2 mm of width. As for the contraction force of a polarizer, it is more preferable that it is 2.40 N or less, and it is still more preferable that it is 2.10 N or less. By setting the shrinkage force of the polarizer in such a range, it is possible to reduce the dimensional change (specifically, shrinkage due to the release of water) of the circularly polarizing plate due to the entrance and exit of water when the high temperature and high humidity environment is shifted to the room temperature environment. As a result, it is thought that the stress which arises in the edge part of a circularly polarizing plate can be reduced, and the change of a phase difference value can be made small. The contracting force of the polarizer may be 0.0 N or more, 0.1 N or more, or 1.0 N or more. By making shrinkage force of a polarizer into this range, appropriate polarization performance is easy to be provided. The shrinkage force of the polarizer is controlled by, for example, adjusting the thickness of the polarizer, or adjusting the crosslinking conditions and stretching conditions of the stretching step.

The shrinkage force of the polarizer can be measured using a thermomechanical analyzer (device name: TMA / SS7100 manufactured by HITACHI). In the said measurement, the polarizer cut to width 2mm and length 50mm so that an absorption axis direction may become a long side can be used as a test piece. This measurement is performed in the dimensional constant mode, and the distance between the chucks is 10 mm. After leaving the test piece in a room having a temperature of 23 ° C. and a relative humidity of 55% for 24 hours or more, the temperature setting in the sample room was increased from 23 ° C. to 80 ° C. for 1 minute, and after the temperature was raised, the temperature in the sample room was maintained at 80 ° C. Set it. After the temperature was raised and left for 4 hours, the shrinkage force in the absorption axis direction of the test piece was measured under an environment of 80 ° C.

The polarizer of the polarizing plate is an absorption type polarizer having the property of absorbing linearly polarized light having a vibration plane parallel to the absorption axis and transmitting linearly polarized light having a vibration plane perpendicular to the absorption axis (parallel to the transmission axis). Can be. As a polarizer, the polarizer which adsorbed and oriented a dichroic dye to the uniaxially stretched polyvinyl alcohol-type resin film can be used suitably. The polarizer is, for example, a step of uniaxially stretching a polyvinyl alcohol-based resin film; Adsorbing a dichroic dye by dyeing a polyvinyl alcohol-based resin film with a dichroic dye; Treating a polyvinyl alcohol-based resin film adsorbed with a dichroic dye with a crosslinking solution such as an aqueous boric acid solution; And it can manufacture by the method containing the process of water washing after the process by a crosslinking liquid.

As polyvinyl alcohol-type resin, what saponified polyvinyl acetate type resin can be used. As polyvinyl acetate type resin, the copolymer etc. with the other monomer copolymerizable with vinyl acetate besides the polyvinyl acetate which is a homopolymer of vinyl acetate are mentioned. Examples of the other monomer copolymerizable with vinyl acetate include unsaturated carboxylic acids, olefins, vinyl ethers, unsaturated sulfonic acids, (meth) acrylamides having an ammonium group, and the like.

In this specification, "(meth) acryl" means at least one selected from acryl and methacryl. The same applies to "(meth) acryloyl", "(meth) acrylate" and the like.

The saponification degree of polyvinyl alcohol-type resin is 85-100 mol% normally, and 98 mol% or more is preferable. The polyvinyl alcohol-based resin may be modified, for example, polyvinyl formal or polyvinyl acetal modified with aldehydes may be used. The average polymerization degree of polyvinyl alcohol-type resin is 1000-10000 normally, and 1500-5000 are preferable. The average polymerization degree of polyvinyl alcohol-type resin can be calculated | required based on JISK6726.

What formed such a polyvinyl alcohol-type resin into a film is used as a far film of a polarizer (polarizer). The method of forming a polyvinyl alcohol-type resin into a film is not specifically limited, A well-known method is employ | adopted. Although the thickness of a polyvinyl alcohol-type raw film is not specifically limited, In order to make thickness of a polarizer into 15 micrometers or less, it is preferable to use 5-35 micrometers. More preferably, it is 20 micrometers or less.

Uniaxial stretching of a polyvinyl alcohol-type resin film can be performed before dyeing, simultaneously with dyeing, or after dyeing of a dichroic dye. When uniaxial stretching is performed after dyeing, this uniaxial stretching may be performed before or during crosslinking treatment. In addition, you may uniaxially stretch in several of these steps.

At the time of uniaxial stretching, you may extend | stretch uniaxially between the rolls from which a circumferential speed differs, and may extend | stretch uniaxially using a hot roll. Moreover, uniaxial stretching may be dry stretching which extends | stretches in air | atmosphere, and wet extending | stretching may be performed in the state which swelled the polyvinyl alcohol-type resin film using a solvent and water. The draw ratio is usually 3 to 6 times.

As a method of dyeing a polyvinyl alcohol-type resin film with a dichroic dye, the method of immersing the said film in the aqueous solution containing a dichroic dye is employ | adopted, for example. As a dichroic dye, iodine and a dichroic organic dye are used. On the other hand, it is preferable that the polyvinyl alcohol-type resin film is immersed in water before a dyeing process.

As a crosslinking process after dyeing with a dichroic dye, the method of immersing the dyed polyvinyl alcohol-type resin film in boric acid containing aqueous solution is employ | adopted normally. When using iodine as a dichroic dye, it is preferable that this boric acid containing aqueous solution contains potassium iodide.

The thickness of a polarizer is 20 micrometers or less normally, Preferably it is 15 micrometers or less, More preferably, it is 13 micrometers or less, More preferably, it is 10 micrometers or less, Especially preferably, it is 8 micrometers or less. The thickness of a polarizer is 2 micrometers or more normally, and it is preferable that it is 3 micrometers or more. By examination of the present inventors, it became clear that the change of the reflection color of a circularly polarizing plate is caused by the change of the phase difference value of a retardation film. In addition, it became clear that the change of the retardation value of the retardation film depends on the dimensional shrinkage rate (specifically, shrinkage due to the release of water) of the circularly polarizing plate due to the entry and exit of moisture. Such a dimensional change is caused by shifting from a high temperature, high humidity environment to a room temperature environment. Therefore, from the viewpoint of reducing the effect of shrinkage of the polarizer, it is effective to prevent the change in color from making the thickness of the polarizer 15 µm or less.

As a polarizer, as described in Unexamined-Japanese-Patent No. 2016-170368, you may use the thing in which the dichroic dye was oriented in the cured film by which the liquid crystal compound was superposed | polymerized. As a dichroic dye, what has absorption in the range of wavelength 380-800 nm can be used, and it is preferable to use an organic dye. As a dichroic dye, an azo compound is mentioned, for example. The liquid crystal compound is a liquid crystal compound capable of polymerizing while being oriented, and may have a polymerizable group in a molecule. Moreover, you may form a polarizer from the dichroic dye which has liquid crystal, as described in the international publication 2011/024891 pamphlet.

(2) protective film

In the circular polarizing plate of the present invention, the moisture permeability of the protective film disposed on the side opposite to the retardation film side in the polarizer is 450 g / m 2 · 24 hr. 300 g / m 2 · 24 hr. It is preferable that it is the following and 150 g / m <2> * 24hr. More preferably, it is 100 g / m <2> * 24 hr. More preferably, it is 50 g / m <2> * 24 hr. You may do this. The lower limit of the moisture permeability of such a protective film is not specifically limited, 0 g / m <2> * 24hr. May be in excess.

When a protective film shows such a water vapor transmission rate, a protective film prevents penetration | invasion of water into a polarizer in a high humidity environment, and elongation of the polarizing plate by which a polarizer swells with water is suppressed. In addition, since the intrusion of moisture is prevented in advance, it is considered that the shrinkage of the polarizing plate generated when the polarizer spouts moisture when the transition from a high humidity environment to a relatively dry room temperature environment is also suppressed. Thus, the phase difference value change of the retardation film by the stress propagation to the retardation film which the expansion-contraction and contraction of the polarizing plate itself generate | occur | produce can be prevented, As a result, the change of a reflection color can be suppressed.

In order to satisfy the range of the said water vapor transmission rate, polyolefin resin, polyester resin, polycarbonate resin, or (meth) acrylic resin can be used for the material of such a protective film.

The water vapor transmission rate of a protective film may be a value measured based on JISZ0220, and temperature and humidity conditions can be 40 degreeC and 90% RH.

When a circular polarizing plate is substantially rectangular and a protective film is a stretched film, it is preferable that the extending direction of a protective film and the short side direction of a circular polarizing plate are substantially parallel. If the extending direction and the short side direction exist in such a relationship, there exists a tendency for the color change of a circularly polarizing plate to become small regardless of the direction of the slow axis of a retardation film. When the stretching direction of the protective film is parallel to the short side, the shrinkage force in the stretching direction of the protective film due to the stretching relaxation of the polarizer and the protective film under a high temperature environment is smaller than that when parallel to the long side, and the color change is small. I think I lose.

The fact that the extending direction of a protective film and the short side direction of a circular polarizing plate are substantially parallel includes not only the case where both are parallel, but also the case where the angle which both make is 0 +/- 10 degrees. The angle formed by the stretching direction of the protective film and the short side direction of the circular polarizing plate is preferably 0 ± 5 °.

The protective film laminated | stacked on the visual recognition side of a polarizer, and a display element side is a thermoplastic resin which has a translucent (preferably optically transparent), for example, linear polyolefin resin (polypropylene resin etc.), ring shape Iii) polyolefin resins such as polyolefin resins (norbornene resins, etc.); Cellulose resins such as triacetyl cellulose and diacetyl cellulose; Polyester resins such as polyethylene terephthalate and polybutylene terephthalate; Polycarbonate resins; (Meth) acrylic resins such as methyl methacrylate resin; Polystyrene resin; Polyvinyl chloride resins; Acrylonitrile butadiene styrene resin; Acrylonitrile-styrene resins; Polyvinyl acetate type resin; Polyvinylidene chloride-based resins; Polyamide-based resins; Polyacetal resins; Modified polyphenylene ether resins; Polysulfone resins; Polyether sulfone resin; Polyarylate resins; Polyamideimide resin; It may be a film made of polyimide resin or the like. In this invention, it is preferable that a protective film is a film which consists of polyolefin resin, cellulose resin, or (meth) acrylic-type resin.

As chain | strand polyolefin resin, polyethylene resin (polyethylene resin which is a homopolymer of ethylene and copolymer mainly ethylene), polypropylene resin (polypropylene resin which is a homopolymer of propylene, and copolymer mainly propylene) and In addition to the homopolymer of the same linear olefin, the copolymer which consists of 2 or more types of linear olefins is mentioned.

Cyclic polyolefin type resin is a generic term of resin superposed | polymerized using a cyclic olefin as a polymerization unit, For example, Unexamined-Japanese-Patent No. 1-240517, Unexamined-Japanese-Patent No. 3-14882, and Unexamined-Japanese-Patent No. 3 The resin described in -122137 grade | etc., Is mentioned. Specific examples of the cyclic polyolefin resin include ring-opening (co) polymers of cyclic olefins, addition polymers of cyclic olefins, copolymers of cyclic olefins with chain olefins such as ethylene and propylene (typically random copolymers), and these Graft polymers modified with unsaturated carboxylic acids and derivatives thereof, and hydrides thereof. Especially, norbornene-type resin using norbornene-type monomers, such as a norbornene and a polycyclic norbornene-type monomer, is used suitably as cyclic olefin.

Polyester-based resin is resin which has an ester bond except the following cellulose ester-type resin, and what consists of polycondensates of polyhydric carboxylic acid or its derivative (s) and a polyhydric alcohol is common. Divalent dicarboxylic acid or its derivative can be used as polyhydric carboxylic acid or its derivative, For example, terephthalic acid, isophthalic acid, dimethyl terephthalate, and dimethyl naphthalene dicarboxylic acid are mentioned. Divalent diol can be used as a polyhydric alcohol, For example, ethylene glycol, a propanediol, butanediol, neopentyl glycol, cyclohexane dimethanol is mentioned. As a representative example of polyester resin, the polyethylene terephthalate which is a polycondensate of terephthalic acid and ethylene glycol is mentioned.

(Meth) acrylic-type resin is resin which makes the compound which has a (meth) acryloyl group the main structural monomer. Specific examples of the (meth) acrylic resins include poly (meth) acrylic acid esters such as polymethyl methacrylate; Methyl methacrylate- (meth) acrylic acid copolymer; Methyl methacrylate- (meth) acrylic acid ester copolymer; Methyl methacrylate-acrylic acid ester- (meth) acrylic acid copolymer; Methyl (meth) acrylate-styrene copolymers (MS resin and the like); Copolymers of methyl methacrylate with a compound having an alicyclic hydrocarbon group (for example, methyl methacrylate-cyclohexyl copolymer, methyl methacrylate-norbornyl copolymer, etc.); . Preferably, a polymer having a poly (meth) acrylic acid C _1-6 alkyl ester such as methyl poly (meth) acrylate as the main component is used, and more preferably, methyl methacrylate as the main component (50 to 100% by weight, Preferably, the methyl methacrylate type resin made into 70 to 100 weight%) is used.

Cellulose ester-type resin is ester of a cellulose and a fatty acid. Specific examples of the cellulose ester-based resin include cellulose triacetate, cellulose diacetate, cellulose tripropionate, and cellulose dipropionate. Moreover, these copolymers and the thing in which one part of hydroxyl group was modified by another substituent are mentioned. Among these, cellulose triacetate (triacetyl cellulose) is particularly preferable.

Polycarbonate resin is an engineering plastic which consists of a polymer in which the monomeric unit couple | bonded through the carbonate group.

Although the thickness of a protective film is 1-100 micrometers normally, it is preferable that it is 5-60 micrometers from a viewpoint of strength, handleability, etc., It is more preferable that it is 10-55 micrometers, It is further more preferable that it is 15-40 micrometers.

The protective film bonded to one side or both sides of a polarizer may be comprised with the same kind of thermoplastic resin, and may be comprised with the heterogeneous thermoplastic resin. Moreover, thickness may be the same and may differ. Moreover, it may have the same phase difference characteristic, and may have a different phase difference characteristic.

As described above, at least one of the protective films has a hard coat layer, an antiglare layer, a light diffusion layer, an antireflection layer, a low refractive index layer, an antistatic layer, and an antifouling layer on its outer surface (surface opposite to the polarizer). You may have a surface treatment layer (coating layer) like (iii). In addition, the thickness of a protective film includes the thickness of a surface treatment layer.

A protective film can be bonded to a polarizer through an adhesive bond layer or an adhesive layer, for example. As an adhesive agent which forms an adhesive bond layer, an aqueous adhesive agent, an active energy ray curable adhesive agent, or a thermosetting adhesive agent can be used, Preferably it is an aqueous adhesive agent and an active energy ray curable adhesive agent. As an adhesive layer, what is mentioned later can be used.

As an aqueous adhesive agent, the adhesive agent which consists of polyvinyl alcohol-type resin aqueous solution, an aqueous two-component urethane emulsion adhesive, etc. are mentioned. Especially, the aqueous adhesive which consists of aqueous solution of polyvinyl alcohol-type resin is used suitably. As polyvinyl alcohol-type resin, in addition to the vinyl alcohol homopolymer obtained by saponifying polyvinyl acetate which is a homopolymer of vinyl acetate, the polyvinyl alcohol-type air obtained by saponifying the copolymer of vinyl acetate and the other monomer copolymerizable with this. The modified polyvinyl alcohol polymer etc. which partially modified | polymerized or these hydroxyl groups can be used. The aqueous adhesive may include a crosslinking agent such as an aldehyde compound (glyoxal, etc.), an epoxy compound, a melamine compound, a methylol compound, an isocyanate compound, an amine compound, a polyvalent metal salt, and the like.

When using an aqueous adhesive agent, after bonding a polarizer and a protective film, it is preferable to perform the drying process for removing the water contained in an aqueous adhesive agent. After a drying process, you may provide the curing process cured at the temperature of 20-45 degreeC, for example.

The said active energy ray curable adhesive agent is an adhesive agent containing the curable compound hardened | cured by irradiation of active energy rays, such as an ultraviolet-ray, visible light, an electron beam, and X-ray, Preferably it is an ultraviolet curable adhesive agent.

The curable compound may be a cationically polymerizable curable compound or a radically polymerizable curable compound. As a cationically polymerizable curable compound, For example, an epoxy type compound (compound which has one or two or more epoxy groups in a molecule), an oxetane type compound (compound which has one or two or more oxetane rings in a molecule), or these Combinations. As a radically polymerizable curable compound, it is a (meth) acrylic-type compound (compound which has one or two or more (meth) acryloyloxy groups in a molecule), the other vinyl type compound which has a radically polymerizable double bond, for example, or A combination of these. You may use together a cationically polymerizable curable compound and a radically polymerizable curable compound. The active energy ray curable adhesive usually further contains a cationic polymerization initiator and / or a radical polymerization initiator for initiating the curing reaction of the curable compound.

When bonding a polarizer and a protective film, in order to improve adhesiveness, you may surface-treat at least any one of these bonding surfaces. Examples of the surface activation treatment include dry treatment such as corona treatment, plasma treatment, discharge treatment (glow discharge treatment, and the like), flame treatment, ozone treatment, UV ozone treatment, ionizing active line treatment (ultraviolet treatment, electron beam treatment, and the like); Wet processes, such as the ultrasonication, saponification process, and anchor coat process using solvents, such as water and acetone, are mentioned. These surface activation processes may be performed independently and may combine 2 or more.

When the protective film is bonded to both surfaces of the polarizer, the adhesive for bonding these protective films may be the same kind of adhesive or different kinds of adhesives.

<Phase difference film>

The circularly polarizing plate of this invention has a retardation film, and a retardation film contains a retardation layer. A stretched film may be sufficient as a retardation layer, and the material of a stretched film is employ | adopted by what was illustrated to resin which forms the above-mentioned protective film. In this case, the retardation layer may be a stretched film made of polyolefin resin or polycarbonate resin. It is preferable that a retardation layer has a layer comprised from the composition containing a polymeric liquid crystal compound. The layer comprised from the composition containing a polymeric liquid crystal compound means the layer which hardened the polymeric liquid crystal compound specifically ,. In this specification, the layer which gives retardation of (lambda) / 2, the layer (positive A layer), positive C layer, etc. which give a phase difference of (lambda) / 4 may be named generically, and may be called retardation layer. In addition, the retardation film may contain the orientation film mentioned later.

As a layer which gives the phase difference of (lambda) / 2, Preferably it means the layer whose in-plane phase difference value in wavelength 550nm is 200-280 nm, More preferably, means the layer whose in-plane phase difference value is 215-265 nm. do. As a layer which gives the phase difference of (lambda) / 4, Preferably it means the layer whose in-plane phase difference value in wavelength 550nm is 100-160 nm, More preferably, means the layer whose in-plane phase difference value is 110-150 nm. do. The positive C layer may be a layer having a refractive index of nx ≒ ny <nz. The retardation value in the thickness direction of the positive C layer may be -50 nm to -150 nm and may be -70 nm to -120 nm at a wavelength of 550 nm. The retardation layer may exhibit positive wavelength dispersion or may exhibit reverse wavelength dispersion.

The layer on which the polymerizable liquid crystal compound is cured is formed, for example, on an alignment film formed on a substrate. The base material may have a function of supporting an alignment film, and may be a base material formed long. This base material can function as a mold release support body, and can support the retardation layer for transcription | transfer. Moreover, it is preferable to have the adhesive force of the grade so that the surface can peel. As said base material, the resin film exemplified as a material of the said protective film is mentioned.

Although it does not specifically limit as thickness of a base material, It is preferable to set it as the range of 20 micrometers or more and 200 micrometers or less, for example. If the thickness of the substrate is 20 µm or more, strength is imparted. On the other hand, when thickness is 200 micrometers or less, when cutting a base material and making it into a base material of a sheet | leaf, the increase of a process waste and abrasion of a cutting blade can be suppressed.

In addition, the base material may be given various blocking prevention processes. Examples of the antiblocking treatment include a treatment for easily adhering the treatment, a filler to overcome the filler, and the like, and an embossing (knurling treatment). By performing such a blocking prevention process with respect to a base material, the sticking | bonding of the base materials at the time of winding up a base material, what is called blocking can be prevented effectively, and it becomes possible to manufacture an optical film with high productivity.

The layer which hardened the polymeric liquid crystal compound is formed on a base material through an orientation film. That is, the layer laminated | stacked in order of a base material and an oriented film, and the layer which hardened the polymeric liquid crystal compound is laminated | stacked on the said oriented film.

The alignment film is not limited to the vertical alignment film, and may be an alignment film for horizontally aligning the molecular axis of the polymerizable liquid crystal compound, or may be an alignment film for tilting the molecular axis of the polymerizable liquid crystal compound. As an oriented film, it is preferable that it has solvent tolerance which does not melt | dissolve by coating etc. of the composition containing the polymeric liquid crystal compound mentioned later, and has heat resistance in heat processing for removal of a solvent and the orientation of a liquid crystal compound. Examples of the alignment film include a groove alignment film in which an uneven pattern or a plurality of grooves are formed and aligned on an alignment film, an optical alignment film, and a surface containing an alignment polymer. The thickness of the alignment film is usually in the range of 10 nm to 10000 nm, preferably in the range of 10 nm to 1000 nm, more preferably 500 nm or less, and still more preferably in the range of 10 nm to 200 nm.

As resin used for an oriented film, if it is resin used as a material of a well-known aligning film, it will not specifically limit, The hardened | cured material etc. which hardened the conventionally well-known monofunctional or polyfunctional (meth) acrylate type monomer in presence of a polymerization initiator are used. It is available. Specifically, as the (meth) acrylate monomer, 2-ethylhexyl acrylate, cyclohexyl acrylate, diethylene glycol mono 2-ethylhexyl ether acrylate, diethylene glycol monophenyl ether acrylate, tetraethylene glycol, for example Monophenyl ether acrylate, trimethylol propane triacrylate, lauryl acrylate, lauryl methacrylate, isobornyl acrylate, isobornyl methacrylate, 2-phenoxyethyl acrylate, tetrahydrofurfuryl acryl Latex, 2-hydroxypropyl acrylate, benzyl acrylate, tetrahydrofurfuryl methacrylate, 2-hydroxyethyl methacrylate, benzyl methacrylate, cyclohexyl methacrylate, methacrylic acid, urethane acrylate, etc. Can be illustrated. In addition, as resin, these 1 type may be sufficient and 2 or more types of mixtures may be sufficient.

Although it does not specifically limit about the kind of polymeric liquid crystal compound used by this embodiment, From the shape, it is a rod-shaped type (rod-shaped liquid crystal compound) and a disk-shaped type (disk-shaped liquid crystal compound, Discotic liquid crystal compound). In addition, there are low molecular type and high polymer type, respectively. On the other hand, a polymer generally means that the degree of polymerization is 100 or more (polymer physics-phase transition dynamics, Masao Doi, 2 pages, Iwanami Bookstore, 1992).

In this embodiment, any polymeric liquid crystal compound can also be used. Moreover, you may use 2 or more types of rod-like liquid crystal compounds, 2 or more types of discotic liquid crystal compounds, or a mixture of a rod-shaped liquid crystal compound and a discotic liquid crystal compound.

In addition, as a rod-shaped liquid crystal compound, what was described, for example in Claim 1 of Unexamined-Japanese-Patent No. 11-513019, or Paragraph [0026]-[0098] of Unexamined-Japanese-Patent No. 2005-289980 can be used suitably. have. Examples of the discotic liquid crystal compound include those described in paragraphs [0020] to [0067] of JP 2007-108732 A, or paragraphs [0013] to [0108] of JP 2010-244038 A. It can use suitably.

The polymerizable liquid crystal compound may use two or more types together. In that case, at least 1 type has 2 or more polymerizable groups in a molecule | numerator. That is, it is preferable that the layer which hardened the said polymeric liquid crystal compound is a layer in which the liquid crystal compound which has a polymeric group was fixed by superposition | polymerization and formed. In this case, after forming the layer, it is no longer necessary to exhibit liquid crystal.

The polymerizable liquid crystal compound has a polymerizable group capable of carrying out a polymerization reaction. As the polymerizable group, a functional group capable of addition polymerization reaction such as a polymerizable ethylenically unsaturated group or a ring polymerizable group is preferable. More specifically, as a polymerizable group, a (meth) acryloyl group, a vinyl group, a styryl group, an allyl group, etc. are mentioned. Especially, a (meth) acryloyl group is preferable. In addition, a (meth) acryloyl group is a concept containing both a methacryloyl group and an acryloyl group.

The layer which hardened the polymeric liquid crystal compound can be formed by coating the composition containing a polymeric liquid crystal compound on an alignment film, for example, and irradiating an active energy ray, as mentioned later. The said composition may contain components other than the polymerizable liquid crystal compound mentioned above. For example, it is preferable that a polymerization initiator is contained in the said composition. As the polymerization initiator, for example, a thermal polymerization initiator or a photopolymerization initiator is selected according to the type of the polymerization reaction. For example, as a photoinitiator, the (alpha)-carbonyl compound, the acyloin ether, the (alpha) -hydrocarbon substituted aromatic acyloin compound, a polynuclear quinone compound, the combination of a triarylimidazole dimer, and p-aminophenyl ketone, etc. are mentioned. . It is preferable that it is 0.01-20 mass% with respect to the total solid in the said coating liquid, and, as for the usage-amount of a polymerization initiator, it is more preferable that it is 0.5-5 mass%.

A polymerizable monomer may be contained in the said composition from the point of the uniformity of a coating film, and the strength of a film | membrane. A radically polymerizable or cationically polymerizable compound is mentioned as a polymerizable monomer. Especially, a polyfunctional radically polymerizable monomer is preferable.

As a polymerizable monomer, what can copolymerize with the polymerizable liquid crystal compound mentioned above is preferable. It is preferable that it is 1-50 mass% with respect to the total mass of a polymeric liquid crystal compound, and, as for the usage-amount of a polymeric monomer, it is more preferable that it is 2-30 mass%.

Surfactant may be contained in the said composition from the point of the uniformity of a coating film, and the strength of a film | membrane. As surfactant, a conventionally well-known compound is mentioned. Especially, especially a fluorine compound is preferable.

A solvent may be contained in the said composition, and an organic solvent is used preferably. As the organic solvent, for example, amide (e.g., N, N-dimethylformamide), sulfoxide (e.g., dimethyl sulfoxide), heterocyclic compound (e.g., pyridine), hydrocarbon (e.g., benzene, hexane), alkyl halide ( For example, chloroform, dichloromethane), esters (e.g. methyl acetate, ethyl acetate, butyl acetate), ketones (e.g. acetone, methyl ethyl ketone), ethers (e.g. tetrahydrofuran, 1,2-dimethoxyethane) Can be mentioned. Especially, alkyl halide and ketone are preferable. Moreover, you may use together 2 or more types of organic solvents.

The said composition contains various orientation agents, such as a vertical orientation promoter, such as a polarizer interface side vertical aligning agent and an air interface side vertical aligning agent, and horizontal alignment promoters, such as a polarizer interface side horizontal aligning agent and an air interface side horizontal aligning agent. You may be. In addition to the above components, the composition may contain an adhesion improving agent, a plasticizer, a polymer, and the like.

The said active energy ray contains an ultraviolet-ray, visible light, an electron beam, and X-ray, Preferably it is an ultraviolet-ray. As the light source of the active energy ray, for example, low pressure mercury lamp, medium pressure mercury lamp, high pressure mercury lamp, ultra high pressure mercury lamp, xenon lamp, halogen lamp, carbon arc lamp, tungsten lamp, gallium lamp, excimer laser, wavelength range 380 nm to 440 nm An LED light source which emits light, a chemical lamp, a black light lamp, a microwave excited mercury lamp, a metal halide lamp, etc. are mentioned.

Irradiation intensity of an ultraviolet-ray is 100 mW / cm <2> -3,000 mW / cm <2> normally. The ultraviolet irradiation intensity is preferably an intensity in a wavelength range effective for activating a cationic polymerization initiator or a radical polymerization initiator. The time to irradiate an ultraviolet-ray is 0.1 second-10 minutes normally, Preferably it is 0.1 second-5 minutes, More preferably, it is 0.1 second-3 minutes, More preferably, it is 0.1 second-1 minute.

In this embodiment, it is preferable that the thickness of retardation layer is 0.5 micrometer or more. Moreover, it is preferable that it is 10 micrometers or less, and, as for the thickness of the said retardation layer, it is more preferable that it is 5 micrometers or less. In addition, the above-mentioned upper limit and lower limit can be combined arbitrarily. Sufficient durability can be acquired as the thickness of a phase difference layer is more than the said lower limit. If the thickness of the retardation layer is below the upper limit, it can contribute to the thinning of the circular polarizing plate. The thickness of the retardation layer can be adjusted so that a desired in-plane retardation value of the layer giving a phase difference of λ / 4, a layer giving a phase difference of λ / 2, or a positive C layer, and a phase difference value in the thickness direction are obtained.

The retardation film may include one layer of the cured polymerizable liquid crystal compound, or may include two or more layers of the cured polymerizable liquid crystal compound. When the retardation film includes two layers of a cured polymerizable liquid crystal compound, the two layers are a layer giving a phase difference of λ / 4 and a positive C layer, or a layer giving a phase difference of λ / 4 and λ / 2. It is preferable that it is a layer which gives the phase difference of. In the case where the retardation film includes two layers of the cured polymerizable liquid crystal compound, the retardation film is prepared by producing a cured layer of the polymerizable liquid crystal compound on the alignment film, respectively, and laminating both of them through an adhesive layer or an adhesive layer. It may be manufactured. After laminating both, the substrate and the alignment film can be peeled off. It is preferable that it is 3-30 micrometers, and, as for the thickness of the retardation film in this invention, it is more preferable that it is 5-25 micrometers.

<Adhesive layer>

An adhesive layer can be comprised by the adhesive composition which has resin, such as (meth) acrylic-type, rubber type, urethane type, ester type, silicone type, and polyvinyl ether type as a main component. Especially, the adhesive composition which uses (meth) acrylic-type resin which is excellent in transparency, weather resistance, heat resistance, etc. as a base polymer is suitable. The pressure-sensitive adhesive composition may be an active energy ray curing type or a thermosetting type. The thickness of an adhesive layer is 3-30 micrometers normally, Preferably it is 3-25 micrometers.

As (meth) acrylic-type resin (base polymer) used for an adhesive composition, (meth), such as butyl (meth) acrylate, ethyl (meth) acrylate, isooctyl (meth) acrylate, and 2-ethylhexyl (meth) acrylate, for example The polymer or copolymer which uses 1 type, or 2 or more types of acrylate ester as a monomer is used suitably. It is preferable to copolymerize a polar monomer to a base polymer. Examples of the polar monomers include (meth) acrylic acid, 2-hydroxypropyl (meth) acrylate, hydroxyethyl (meth) acrylate, (meth) acrylamide, N, N-dimethylaminoethyl (meth) acrylate, and glycy The monomer which has a carboxyl group, a hydroxyl group, an amide group, an amino group, an epoxy group, etc. like a dill (meth) acrylate is mentioned.

Although the adhesive composition may contain only the said base polymer, it usually contains a crosslinking agent further. As a crosslinking agent, it is a bivalent or more metal ion, and forms a carboxylic acid metal salt between a carboxyl group; A polyamine compound, forming an amide bond between carboxyl groups; Polyepoxy compounds and polyols, forming ester bonds with carboxyl groups; It is a polyisocyanate compound and what forms an amide bond between carboxyl groups is illustrated. Especially, a polyisocyanate compound is preferable.

<Front plate>

The front plate is disposed on the viewing side of the polarizing plate. The front plate may be laminated to the polarizing plate through an adhesive layer. As an adhesive layer, the adhesive layer and adhesive bond layer mentioned above are mentioned, for example. The front plate can be laminated on the protective film 11 in the polarizing plate 1 via an adhesive layer.

As a front plate, the window film etc. which comprise a hard-coat layer in at least one surface of glass and a resin film are mentioned. As glass, high permeation glass and tempered glass can be used, for example. When using a thin transparent face material especially, the glass which chemically strengthened is preferable. The thickness of glass can be 100 micrometers-5 mm, for example.

The window film including the hard coat layer on at least one surface of the resin film may have a flexible property as opposed to conventional glass. The thickness of a hard coat layer is not specifically limited, For example, 5-100 micrometers may be sufficient.

Examples of the resin film include cycloolefin derivatives having units of monomers containing cycloolefins such as norbornene or polycyclic norbornene monomers, cellulose (diacetyl cellulose, triacetyl cellulose, acetyl cellulose butyrate, isobutyl ester cellulose, Propionyl cellulose, butyryl cellulose, acetyl propionyl cellulose) ethylene-vinyl acetate copolymer, polycycloolefin, polyester, polystyrene, polyamide, polyetherimide, polyacryl, polyimide, polyamideimide, polyethersulfone, Polysulfone, polyethylene, polypropylene, polymethylpentene, polyvinyl chloride, polyvinylidene chloride, polyvinyl alcohol, polyvinyl acetal, polyether ketone, polyether ether ketone, polyether sulfone, polymethyl methacrylate, polyethylene tere Phthalate, Paul The film may be formed of a polymer such as ributylene terephthalate, polyethylene naphthalate, polycarbonate, polyurethane or epoxy. An unstretched, uniaxial or biaxially oriented film can be used for the resin film. These polymers can be used individually or in mixture of 2 or more types, respectively. As the resin film, a polyamideimide film or polyimide film excellent in transparency and heat resistance, a monoaxial or biaxially stretched polyester film, a cycloolefin derivative film that is excellent in transparency and heat resistance, and can cope with the enlargement of the film, polymethyl Preferred are methacrylate films and triacetyl cellulose and isobutyl ester cellulose films that are transparent and optically anisotropic. The thickness of a resin film is 5-200 micrometers, Preferably, 20-100 micrometers may be sufficient.

The hard coat layer can be formed by curing a hard coat composition containing a reactive material that forms a crosslinked structure by irradiating light or thermal energy. The said hard coat layer can be formed by hardening of the hard-coat composition containing a photocurable (meth) acrylate monomer or an oligomer, a photocurable epoxy monomer, or an oligomer simultaneously. The photocurable (meth) acrylate monomer may include one or more selected from the group consisting of epoxy (meth) acrylate, urethane (meth) acrylate, and polyester (meth) acrylate. The said epoxy (meth) acrylate can be obtained by making the carboxylic acid which has a (meth) acryloyl group react with an epoxy compound.

The hard coat composition may further include one or more selected from the group consisting of a solvent, a photoinitiator and an additive. The additive may include one or more selected from the group consisting of inorganic nanoparticles, a leveling agent and a stabilizer, and in addition, each component generally used in the art may include, for example, an antioxidant, a UV absorber, a surfactant, It may further include a lubricant, antifouling agent and the like.

<Shading Pattern>

The light shielding pattern may be provided as at least a part of the bezel or the housing of the display device to which the front plate or the front plate is applied. The light shielding pattern can be formed on the display element side in the front panel. The light shielding pattern can hide each wiring of the display device so that it is not visually recognized by a user. The color and / or material of the light shielding pattern is not particularly limited, and may be formed of a resin material having various colors such as black, white, and gold. In one embodiment, the thickness of the light shielding pattern may be 2 µm to 50 µm, preferably 4 µm to 30 µm, and more preferably 6 µm to 15 µm. Further, in order to suppress bubble mixing due to the step between the light shielding pattern and the display portion and the visibility of the boundary portion, a shape can be given to the light shielding pattern.

<Method for Manufacturing Circular Polarizing Plate>

A method of manufacturing the circular polarizing plate will be described by taking the circular polarizing plate 100 shown in FIG. 1A as an example. The circular polarizing plate 100 can be manufactured by laminating the polarizing plate 1 and the retardation film 2 through the pressure-sensitive adhesive layer 13.

The polarizing plate 1 can manufacture the polarizer 10 and the protective films 11 and 12 laminated | stacked through an adhesive bond layer, respectively. After preparing a elongate member and joining each member by roll-to-roll, it may cut and manufacture to a predetermined shape, and may cut together after cutting each member to a predetermined shape. After bonding the protective films 11 and 12 to the polarizer 10, you may provide a heating process and a humidity control process.

The retardation film 2 can be manufactured as follows, for example. An alignment film is formed on a base material, and the coating liquid containing a polymeric liquid crystal compound is coated on the alignment film. Active energy rays are irradiated in the state which orientated the polymerizable liquid crystal compound to cure the polymerizable liquid crystal compound. The pressure-sensitive adhesive layer 14 formed on the release film is laminated on the cured layer of the polymerizable liquid crystal compound. Subsequently, the substrate and / or the alignment film are peeled off. Subsequently, the pressure-sensitive adhesive layer 13 formed on the release film is laminated on the protective film 12. The retardation film 2 may prepare a long member, bond each member with a roll-to-roll, and then cut and manufacture the sheet in a predetermined shape. good.

And the circularly-polarizing plate 100 can be manufactured by peeling the peeling film laminated | stacked on the adhesive layer 13, and bonding the retardation film 2 and the polarizing plate 1 through the adhesive layer 13.

<Use>

The circular polarizing plate can be used for various display devices. The display device is a device having a display element, and includes a light emitting element or a light emitting device as a light emitting source. As the display device, for example, a liquid crystal display device, an organic EL display device, an inorganic electroluminescent display (hereinafter also referred to as an inorganic EL) display device, an electron emission display device (for example, an electric field emission display device (also referred to as an FED)), Surface field emission display (also called SED), electronic paper (display using electronic ink or electrophoretic element, plasma display, projection type display (e.g. grating light valve (also called GLV)) display, digital micromirror device And a piezoelectric ceramic display, etc. The liquid crystal display device includes any of a transmissive liquid crystal display device, a transflective liquid crystal display device, etc. These display devices include two-dimensional images. The display device may be a display device, or a stereo display device may display a three-dimensional image. It can use especially effectively for a device or an inorganic EL display device.

EXAMPLES

(1) measuring method of film thickness

It measured using MH-15M which is a digital micrometer by Nikon Corporation.

(2) Measurement method of phase difference value

It measured using the phase difference measuring apparatus KOBRA-WPR (made by Oji Keisoku Kiki Co., Ltd.).

(3) contraction force of polarizer

It cut into 2 mm in width and 50 mm in length by the super cutter (made by Ogino Seiki Seisakusho) so that an absorption axis direction might become a long side. The obtained rectangular chip was used as a test piece. The shrinkage force of the test piece was measured using the thermomechanical analyzer (SAI Nano Technology Co., Ltd. make, model TMA / 6100). This measurement was performed in dimensional constant mode, and the distance between chucks was 10 mm. After leaving the test piece at 23 ° C for 55% of the room for 24 hours or more, the temperature setting in the sample chamber was raised from 23 ° C to 80 ° C for 1 minute, and after the temperature was raised, the temperature in the sample chamber was set to be maintained at 80 ° C. After the temperature was raised and left for 4 hours, the shrinkage force in the long side direction of the test piece was measured under an environment of 80 ° C. In this measurement, the static load was 0 mN, and a SUS probe was used for the jig.

(4) dimensional shrinkage rate of circular polarizer

The dimensional shrinkage rate of the circular polarizing plate was measured as follows. The circularly polarizing plate was cut out to a size of 50 mm in the slow axis direction of the retardation film and 50 mm in the fast axis direction of the retardation film. The cut circular polarizing plate was bonded to an alkali-free glass (manufactured by Corning, product name: Eagle XG) having a thickness of 0.4 mm, and placed in an oven of a high temperature, high humidity environment (temperature 60 ° C, 95% relative humidity) for 168 hours (hr). The dimension of the circularly polarizing plate was measured immediately after taking out from the oven in room temperature environment (temperature 23 degreeC, relative humidity 55%). Then, after storing for 24 hours in room temperature environment, the dimension of the circular polarizing plate was again measured, and the dimensional shrinkage rate of the slow axis direction of the circular polarizing plate was calculated from the inclination of the dimensional change.

(5) moisture permeability of protective film

The water vapor transmission rate of the protective film was measured based on JIS Z 0208. Temperature and humidity conditions were 40 degreeC and 90% RH.

(6) dimensional shrinkage of circular polarizer

The dimensional shrinkage rate of the circular polarizing plate was measured as follows. The circularly polarizing plate was cut out to a size of 50 mm in the slow axis direction of the retardation film and 50 mm in the fast axis direction of the retardation film. The cut circular polarizing plate was bonded to an alkali free glass (manufactured by Corning, product name: Eagle XG) having a thickness of 0.4 mm, and placed in an oven of a high temperature and high humidity environment (temperature 60 ° C, 95% relative humidity) for 168 hr. Using a two-dimensional dimensional measuring device, the circular polarizing plate (initial dimension) before being put into the oven and the slow axis direction of the circular polarizing plate immediately after taking it out of the oven were measured, and the dimensional shrinkage ratio of the circular polarizing plate was determined by the following equation. Calculated.

Dimensional shrinkage rate (%) of circular polarizing plate = (initial dimension-dimensions after heating) / initial dimension * 100

[Production of Phase Difference Layer A]

5 parts (weight average molecular weight: 30,000) and 95 parts of cyclopentanone (solvent) of the photo-alignment material of the following structure were mixed, and the obtained mixture was stirred at 80 degreeC for 1 hour, and the composition A for oriented film formation was obtained.

2 parts which are 1.0 parts of leveling agents (F-556; DIC Corporation make), and a polymerization initiator with respect to 100 parts of mixtures which mixed the polymeric liquid crystal compound 1 shown below and the polymeric liquid crystal compound 2 in the mass ratio of 90:10. -Dimethylamino-2-benzyl-1- (4-morpholinophenyl) butan-1-one ("Irgacure 369 (Irg369)", manufactured by BASF Japan) was added.

Furthermore, N-methyl-2-pyrrolidone (NMP) was added so that solid content concentration might be 13%, and the composition A for liquid crystal cured film formation was obtained by stirring at 80 degreeC for 1 hour.

The polymeric liquid crystal compound 1 was manufactured by the method of Unexamined-Japanese-Patent No. 2010-31223. In addition, the polymeric liquid crystal compound 2 was manufactured according to the method of Unexamined-Japanese-Patent No. 2009-173893. Each molecular structure is shown below.

(Polymerizable Liquid Crystal Compound 1)

(Polymerizable Liquid Crystal Compound 2)

[Manufacture of laminated body which consists of a base material, the orientation film, and the layer which hardened the polymeric liquid crystal compound]

As a base material, the corona treatment was performed on the 50-micrometer-thick cycloolefin type film (brand name "ZF-14-50" by the Nippon Xeon company). The composition A for oriented film formation was apply | coated to the surface in which corona treatment was performed with the bar coater. The coating film was dried at 80 ° C. for 1 minute. The dry coating film was irradiated with polarized UV at an axial angle of 45 degrees using the polarizing UV irradiation apparatus [trade name "SPOT CURE SP-9" of Ushio Denki Corporation, and the alignment film was obtained. Irradiation of polarization UV was performed so that the accumulated light amount in wavelength 313nm might be 100 mJ / cm <2>.

Subsequently, the composition A for forming a liquid crystal cured film was applied onto the alignment film using a bar coater. The coating film was dried at 120 ° C. for 1 minute. The dry coating film was irradiated with ultraviolet rays using a high pressure mercury lamp (trade name: "Unicure VB-15201BY-A" by Ushio Denki Corp.). The irradiation process of ultraviolet-ray was performed in nitrogen atmosphere so that the accumulated light amount in wavelength 365nm may be 500 mJ / cm <2>. Thus, the laminated body which consists of a layer (phase difference layer A) which the base material, the orientation film, and the polymeric liquid crystal compound hardened | cured was obtained.

(Measurement of phase difference value)

The retardation layer A had Re (450) = 121 nm, Re (550) = 142 nm, and Re (650) = 146 nm as phase difference values Re (λ) in each wavelength. As a result, Re (450) / Re (550) = 0.85 and Re (650) / Re (550) = 1.03 were calculated. The retardation layer A was a layer giving a phase difference of λ / 4.

[Production of Phase Difference Layer B]

The composition was prepared in the following order. To 100 parts of Paliocolor LC242 (registered trademark of BASF Corporation) which is a polymerizable liquid crystal compound, 0.1 part of F-556 as a leveling agent and 3 parts of Irgacure 369 as a polymerization initiator were added.

Cyclopentanone was added so that solid content concentration might be 13%, and the composition B for liquid crystal cured film formation was obtained. As the composition B for forming the alignment film, San Eva SE610 manufactured by Nissan Chemical Industries, Ltd. was used.

As a base material, the corona treatment was performed on the 50-micrometer-thick cycloolefin type film (brand name "ZF-14-50" by the Nippon Xeon company). The composition B for oriented film formation was apply | coated with the bar coater on the surface to which corona treatment was performed. The coating film was dried at 80 ° C. for 1 minute to obtain an alignment film.

The composition B for liquid crystal cured film formation was apply | coated on the oriented film using the bar coater, and it dried at 90 degreeC for 120 second. About a coating film, it irradiates an ultraviolet-ray using a high pressure mercury lamp ("Unicure VB-15201BY-A", the product made by Ushio Denki Co., Ltd.) (in nitrogen atmosphere, accumulated light quantity in wavelength 365nm: 500 mJ / cm <2>). ) Thus, the laminated body which consists of the layer (phase difference layer B) which the base material, the orientation film, and the polymeric liquid crystal compound hardened | cured was obtained.

(Measurement of phase difference value)

The retardation layer B was calculated with Rth (550) = -70 nm. In addition, the retardation layer B was a positive C plate.

[Production of Retardation Film C]

Corona treatment (800 W, 10 m / min, bar width 700 mm, 1 Pass) was performed on the phase difference layer A in the laminated body produced by [Production of phase difference layer A]. The adhesive composition prepared below was coated on this corona treated surface using the coating machine (bar coater by Daiichi Rika Co., Ltd.) so that the thickness of an adhesive bond hardening layer might be set to 1 micrometer, and the adhesive composition layer was formed. . The adhesive composition layer formed on the retardation layer A and the retardation layer B obtained by the above-mentioned [production of retardation layer B] were bonded together using the sticking apparatus ("LPA3301" by Fujipla Co., Ltd.). From the retardation layer B side, ultraviolet-ray was irradiated with the belt conveyor ultraviolet irradiation apparatus (the lamp used "H bulb" by Fusion UV Systems, Inc.), and the adhesive composition was hardened, and retardation film C was obtained. In the UVA region, the irradiation intensity was 390 mW / cm 2 and the accumulated light amount was 420 mJ / cm 2, and in the UVB region, the 400 mW / cm 2 and the accumulated light amount was 400 mJ / cm 2. As for retardation film C, the base material, the orientation film, the retardation layer A, the adhesive bond layer, the retardation layer B, the alignment film, and the base material were laminated | stacked in this order.

[Preparation of Adhesive Layer]

The following adhesive layer A and the adhesive layer B were prepared.

Adhesive layer A: 5 micrometer-thick sheet-like adhesive ("NCF 'L2" by the lintech Co., Ltd.)

Adhesive layer B: 25-micrometer-thick sheet-like adhesive ("P-3132" by Lintec Corporation)

[Preparation of Adhesive Composition]

After mixing the cationically curable components a1 to a3 shown below, the cation polymerization initiator and the sensitizer shown below were further mixed. The obtained mixture was degassed and the photocurable adhesive composition was prepared. In addition, the following compounding quantity is based on solid amount.

Cationic curable component a1 (70 parts): 3 ', 4'-epoxycyclohexylmethyl 3', 4'-epoxycyclohexanecarboxylate (trade name: CEL2021P, manufactured by Daicel Co., Ltd.)

Cationic curable component a2 (20 parts): neopentyl glycol diglycidyl ether (trade name: EX-211, manufactured by Nagase Chemtex Co., Ltd.)

Cationic curable component a3 (10 parts): 2-ethylhexyl glycidyl ether (trade name: EX-121, manufactured by Nagase Chemtex Co., Ltd.)

Cationic polymerization initiator (2.25 parts (solid amount)): Brand name: 50% propylene carbonate solution of CPI-100 (manufactured by San Afro Co., Ltd.)

Sensitizer (2 parts): 1,4-diethoxynaphthalene

[Preparation of Protective Film]

The following protective film was prepared. Table 1 shows the moisture permeability of the protective films A to C.

Protective film A: Cyclic polyolefin-based resin film (Trade name "Aton" made by JSR Corporation) of thickness 15micrometer

Protective film B: Cyclic polyolefin type resin film of 13 micrometers in thickness (brand name "ZF14-013" made by Nippon Xeon Co., Ltd.]]

Protective film C: Film which formed hard coat layer of thickness 7 micrometers in triacetyl cellulose film of thickness 25 micrometers (trade name "25KCHC-HC" of the plate | board Insatsu Corporation).

Protective film D: 20-micrometer-thick triacetyl cellulose film [trade name "ZRG20SL" of Fujifilm Corporation]

[Production of Polarizer A]

Polyvinyl alcohol film (average degree of polymerization of about 2400, saponification degree of 99.9 mol% or more) of 30 μm in thickness is uniaxially stretched by about 4 times by dry stretching, and is pure at 40 ° C. while maintaining a tension state. After soaking in for 40 seconds, it was immersed in 28 degreeC for 30 second in aqueous solution whose weight ratio of iodine / potassium iodide / water is 0.052 / 5.7 / 100, and dyeing process was performed. Then, it was immersed for 120 second at 70 degreeC in the aqueous solution whose weight ratio of potassium iodide / boric acid / water is 11.0 / 6.2 / 100. Subsequently, after 15 seconds of washing with pure water at 8 ° C., the mixture was dried at 60 ° C. for 50 seconds and then at 75 ° C. for 20 seconds in a state maintained at a tension of 300 N, and iodine was adsorbed to the polyvinyl alcohol film. Polarizer A having a thickness of 12 μm was obtained. The shrinkage force in the absorption axis direction of the polarizer A was 2.08 N / 2 mm.

Example 1

[Production of Polarizing Plate]

The aqueous adhesive was apply | coated to one surface of the polarizer A, and the corona-treated protective film A was bonded. The water-based adhesive agent was apply | coated to the other surface of the polarizer A, and the protective film D which performed the saponification process was bonded. Then, it dried and the polarizing plate was obtained. The water-based adhesive dissolves three parts of carboxyl group-modified polyvinyl alcohol (trade name "KL-318" obtained from Kuraray Co., Ltd.) with respect to 100 parts of water, and is a polyamide epoxy additive (Daoka) which is a water-soluble epoxy resin. 1.5 parts of Kagaku Kogyo Co., Ltd. brand name "Sumirez resin 650 (30)" and 30% of solid content concentration] are added.

[Production of Circular Polarizer Plate]

The adhesive layer A was bonded to the protective film D in the said polarizing plate. The adhesive layer A was bonded after peeling the base material of the retardation layer A side of retardation film C, and performing the corona treatment on the exposed retardation layer A. Moreover, after peeling the base material on the phase difference layer B side and performing corona treatment on the exposed phase difference layer B, the adhesive layer B was bonded and the circular polarizing plate was produced. At this time, the slow axis of the retardation layer A was 45 degrees with respect to the absorption axis of the polarizer.

The circularly polarizing plate was cut into the rectangle of the size of 140 mm x 70 mm so that the slow axis of retardation film might become parallel to a long side. Through the pressure-sensitive adhesive layer B, the cut circularly polarizing plate was bonded to a glass plate having a thickness of 0.4 mm (manufactured by Corning, product number: EAGLE XG (registered trademark)). In this way, the sample for evaluation was produced.

Example 2

Except having changed the protective film A of Example 1 into the protective film B, the circularly-polarizing plate was produced like Example 1, and the sample for evaluation was produced.

Comparative Example 1

Except having changed the protective film A of Example 1 into the protective film C, the circularly-polarizing plate was produced like Example 1, and the sample for evaluation was produced.

[Evaluation of Reflective Colors]

The produced sample for evaluation was put into the oven of high temperature, high humidity environment (temperature 60 degreeC, 95% relative humidity) for 168 hours. The sample for evaluation was taken out from the oven, and it was left to stand on the room temperature environment (temperature 23 degreeC, relative humidity 55%) for 24 hours. Thereafter, the reflection color of the sample for evaluation was measured.

[Measurement of Reflective Color]

As a reflecting plate, MIRO (5011GP) made from ALANOD Corporation was prepared. This reflecting plate is a mirror reflecting plate having a reflecting surface formed from vapor deposition. The sample for evaluation was arrange | positioned on the said reflecting plate. The reflection color (a *, b *) was measured using the spectrophotometer (Konica Minolta Japan Co., Ltd. brand name: CM-2600d). The reflection color was a value when the light source was D65 and was measured by the SCI method (including specular reflection).

Specifically, the point 5 shown in FIG. 2 was used as a measuring point. Nine points 5 shown in FIG. 2 are points in an area 5 mm inward from the end of the circular polarizing plate, and the short side direction is located at intervals of about 30 mm, and the long side direction is positioned at intervals of about 65 mm. For the evaluation samples produced in Examples 1 to 3 and Comparative Example 1, the reflection color was measured according to the measurement conditions shown in the above-described evaluation of the reflection color, and the absolute value of the color change Δa * b * at each point was measured. Calculated. The color change value of each point was computed based on the direction of a color change, and the difference of the maximum value and minimum value of the color change value of each evaluation sample was made into (DELTA) a * b * (MAX-MIN).

Δa * = a * (after moist heat test) -a * (before moist heat test)

Δb * = b * (after moist heat test) -b * (before moist heat test)

Δa * b * = [(Δa *) ² + (Δb *) ² ] ^1/2

On the other hand, the color change value was Δa * b * when Δa * was 0 or more, and Δa * b * × -1 when Δa * was smaller than 0.

The above result is shown in Table 2.

According to the present invention, it is useful because it is possible to provide a circularly polarizing plate with a small change in the reflection color even when placed in a high temperature, high humidity environment and then placed in a room temperature environment.

1: polarizer
2: retardation film
5: dot
10: polarizer
11, 12: protective film
13, 14: adhesive layer
15: adhesive layer
20, 21: cured layer of polymerizable liquid crystal compound
100, 101, 102: circularly polarizing plate

Claims (9)

A circular polarizing plate in which a polarizing plate and a retardation film are laminated, wherein the polarizing plate includes a polarizer and a protective film, and the protective film is disposed on the side opposite to the retardation film side in the polarizer, and the moisture permeability of the protective film is 450 g. / M 2 · 24 hours or less, wherein the circularly polarizing plate has a dimensional shrinkage rate of 4.1 × 10 ⁻⁴ mm / hour or less. The shape of the main surface is substantially rectangular, and the slow axis of the retardation film is parallel to the long side direction of the circularly polarizing plate, and the slow axis and the polarizer of the retardation film. A circular polarizer having an angle of about 45 ° formed by an absorption axis of. The circularly polarizing plate of Claim 1 or 2 in which the said retardation film contains the layer which the polymeric liquid crystal compound hardened | cured, and the adhesive layer is arrange | positioned on the opposite side to the said polarizing plate side in the said retardation film. The circularly polarizing plate according to any one of claims 1 to 3, further comprising a display panel. The circular polarizing plate of claim 4, wherein the circularly polarizing plate is bendable. The circularly polarizing plate according to claim 4 or 5, further comprising a touch sensor and a window film, wherein the display panel, the touch sensor, the polarizer, and the window film are laminated in this order. The circularly polarizing plate according to claim 4 or 5, further comprising a touch sensor, wherein the display panel, the polarizer, and the touch sensor are stacked in this order. The circularly polarizing plate according to claim 7, further comprising a window film, wherein a display panel, a polarizer, a touch sensor, and a window film are laminated in this order. The display device in which the circularly-polarizing plate of any one of Claims 1-8 was laminated | stacked on the display element via the adhesive layer.

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