KR20200056410A - Long liquid crystal film, long polarizing plate, image display device, and manufacturing method of long liquid crystal film - Google Patents

Abstract

A liquid crystal film containing a photo-alignment layer, a liquid crystal film in which phase difference unevenness is suppressed, a long polarizing plate, an image display device, and a method for manufacturing a long liquid crystal film are provided. A long liquid crystal film having a long base material, a long optical alignment layer, and a long liquid crystal layer having an in-plane retardation in this order, wherein the long liquid crystal film is sandwiched by a linear polarizer and a spectrometer to place the long liquid crystal film in a quenching position. In the case of irradiating light, there is a stripe-shaped region where light leakage occurs, and the slow axis fluctuation Δβ in the stripe-shaped region is greater than 0 ° and less than 0.04 °.

Description

Long liquid crystal film, long polarizing plate, image display device, and manufacturing method of long liquid crystal film

The present invention relates to a long liquid crystal film including a photo-alignment layer, a method for manufacturing the same, and a long polarizing plate comprising the long liquid crystal film, and an image display device.

Conventionally, a liquid crystal film using a polymerizable liquid crystal compound has been proposed, and has been used as a retardation film or a high function film (Patent Document 1). As a typical example of these liquid crystal films, it is known that these liquid crystal films can be obtained by polymerizing a polymerizable liquid crystal compound aligned by alignment control force of an alignment layer provided on a support to fix an alignment state and impart various optical properties. have.

Recently, in order to obtain a liquid crystal film with few defects, it has been proposed to use a photo-alignment layer instead of a previously used rubbing alignment layer (Patent Document 2). Since the photo-alignment layer can perform a process of imparting an orientation regulating force to the alignment layer material in a non-contact manner, it is expected to suppress unevenness and defects caused by foreign substances due to rubbing.

By the way, as a display device to which a liquid crystal film is applied, for example, a liquid crystal display device or an organic EL (electroluminescence) display device can be mentioned. These display devices are constantly subjected to high definition, high dynamic range, and pixel pitch. In more detail, there is a constant demand for higher white luminance and higher black display performance.

With the increase in the performance of such a display device, in addition to defects caused by foreign substances in the liquid crystal film, the influence on the display quality of the display device caused by the phase difference non-uniformity caused by various factors is becoming indispensable. Efforts have been made to exclude these factors (for example, Patent Documents 3 and 4), but the demand for high quality liquid crystal films has not been stopped.

Japanese Patent Application Publication No. Hei 8-094838 Japanese Patent Publication No. 2000-086786 Japanese Patent Application Publication No. 2001-314799 Japanese Patent Application Publication No. 2008-224968

The present invention has been made in view of such a situation, and it is a subject to provide a liquid crystal film, a long polarizing plate, an image display device, and a method for manufacturing a long liquid crystal film, in which phase difference non-uniformity is suppressed with respect to a liquid crystal film including a light alignment layer Shall be

The inventors pay attention to a phenomenon in which polarization once transmitted through the web is re-incident to the web due to reflection or the like when irradiating polarization with respect to the photo-alignment, thereby suppressing light from an unexpectedly polarized state from entering the photo-alignment layer. The following invention was realized by discovering the point which can eliminate unevenness.

[1] A long liquid crystal film having a long substrate, a long optical alignment layer, and a long liquid crystal layer having an in-plane retardation in this order,

In the long liquid crystal layer, when the long liquid crystal film is sandwiched by a linear polarizer and a spectrometer and placed at a quenching position to irradiate light, a stripe-shaped region where light leakage occurs exists, and a slow axis fluctuation in the stripe-shaped region A long liquid crystal film, wherein Δβ is greater than 0 ° and less than 0.04 °.

[2] The long liquid crystal film according to [1], wherein the in-plane retardation of the long liquid crystal layer is in the range of 100 nm to 250 nm.

[3] The long liquid crystal film according to [1] or [2], wherein the in-plane retardation of the long liquid crystal film is in the range of 100 nm to 250 nm.

[4] The long liquid crystal film according to any one of [1] to [3], in which the long base material satisfies the following formula.

｜ Re (550) ｜ ≤10nm

｜ Rth (550) ｜ ≤20nm

[5] The long liquid crystal film according to any one of [1] to [4], wherein the in-plane retardation of the long liquid crystal layer is in the range of 110 nm to 160 nm, and the slow axis forms 45 degrees to the longitudinal direction of the long substrate. .

[6] The long liquid crystal film according to any one of [1] to [5], wherein the in-plane retardation of the long liquid crystal film is in the range of 110 nm to 160 nm, and the slow axis forms 45 degrees to the longitudinal direction of the long substrate.

[7] The long liquid crystal film according to any one of [1] to [6], wherein the long liquid crystal layer satisfies the following formula.

Re (450) / Re (550) <1.0

1.0 <Re (650) / Re (550)

[8] The long liquid crystal film according to any one of [1] to [7], wherein the long liquid crystal film satisfies the following formula.

Re (450) / Re (550) <1.0

1.0 <Re (650) / Re (550)

[9] The long liquid crystal film according to any one of [1] to [8], wherein the ratio of the total area of the stripe-shaped region to the area of the surface of the long liquid crystal layer is 6% or less.

[10] A long polarizing plate in which the long liquid crystal films according to any one of [1] to [9] and the long linear polarizing plates are stacked in alignment with each other in the longitudinal direction.

[11] The absorption axis of the long linear polarizer is 0 ° or 90 ° with respect to the longitudinal direction of the long linear polarizer, and the cross angle with the slow axis of the long liquid crystal film is 45 °. [10] Long polarizing plate described in.

[12] The long polarizing plate according to [11], wherein the in-plane retardation of the long liquid crystal film is in the range of 110 nm to 160 nm.

[13] An image display device comprising a sheet-shaped polarizing plate cut out from the long polarizing plate according to any one of [10] to [12].

[14] The long liquid crystal film according to any one of [1] to [9], wherein the liquid crystal layer is provided to be peelable between at least one of the photo-alignment layer and the liquid crystal layer, or between the long base material and the photo-alignment layer. .

[15] A method for producing a long liquid crystal film according to any one of [1] to [9] and [14],

While conveying the long substrate in the longitudinal direction, it has a photo-alignment step of irradiating ultraviolet rays to the material layer to be a photo-alignment layer formed on the long substrate,

In the photo-alignment process, when irradiating ultraviolet rays to the material layer, the surface opposite to the surface on which the material layer of the long base material is formed is supported by the backup roll,

The manufacturing method of the long liquid crystal film whose maximum height roughness Rz of the surface of a backup roll is 0.7 micrometer or less.

[16] The method for producing a long liquid crystal film according to [15], wherein the reflectance of the surface of the backup roll against ultraviolet rays is 10% or less.

ADVANTAGE OF THE INVENTION According to this invention, the phase difference unevenness of a long liquid crystal film and a long polarizing plate can be reduced, and it becomes possible to obtain the image display apparatus excellent in display quality. Moreover, the manufacturing method of the elongate liquid crystal film which can suppress generation | occurrence | production of a phase difference nonuniformity can be provided.

1 is a conceptual diagram showing a long liquid crystal film of the present invention.
2 is a conceptual diagram showing a long polarizing plate or a circular polarizing plate of the present invention.
3 is a conceptual diagram showing an example of an apparatus for producing a long liquid crystal film of the present invention.
4 is a conceptual diagram showing an example of an apparatus for manufacturing a long polarizing plate of the present invention.
5 is a conceptual diagram showing a display device according to the present invention.
Fig. 6 is an image taken around a stripe-shaped light leakage area actually observed in a long liquid crystal film obtained by a conventional method.
FIG. 7 is a graph of the results of measuring the slow axis direction with respect to the direction (along the white line in FIG. 6) traversing the light leakage region in FIG. 6.
FIG. 8 is an image of a light leakage region different from FIG. 6.
FIG. 9 is a graph of the results of measuring the slow axis direction with respect to the direction (along the white line in FIG. 8) traversing the light leakage region in FIG. 8.

Hereinafter, embodiments of the present invention will be described in detail. In addition, in this specification, the numerical range indicated using "-" means the range which includes the numerical value described before and after that as a lower limit and an upper limit.

First, terms used in the present specification will be described.

Re (λ) and Rth (λ) indicate in-plane retardation at the wavelength λ, and retardation in the thickness direction, respectively. Re (λ) is measured in KOBRA 21ADH, or WR (manufactured by Oji Keisoku Kiki Co., Ltd.) with light having a wavelength of λnm incident in the direction of the film normal. When selecting the measurement wavelength λnm, the wavelength selection filter can be replaced manually or the measurement value can be converted into a program or the like to measure. When the film to be measured is represented by a uniaxial or biaxial refractive index ellipsoid, Rth (λ) is calculated by the following method.

Rth (λ) is the above-mentioned Re (λ), the slow axis in the plane (determined by KOBRA 21ADH, or WR) as the inclined axis (rotation axis) (if there is no ground axis, any direction in the film surface (Referred to as the axis of rotation), the light of wavelength λnm is incident from the inclined direction in 10-degree steps from the normal direction to 50 ° on one side from the normal direction, and all six points are measured, and the measured retardation value and average refractive index KOBRA 21ADH or WR is calculated based on the assumption value of and the input maximum value. In the above, in the case of a film having a direction in which the retardation value is zero at a predetermined inclination angle with the slow axis in the plane as the rotation axis from the normal direction, the retardation value at an inclination angle greater than the inclination angle is its sign. After changing to negative, KOBRA 21ADH, or WR is calculated. In addition, the retardation value is measured from two inclined two directions using the slow axis as the inclined axis (rotation axis) (if there is no ground axis, an arbitrary direction in the film plane is used as the rotation axis), and the value and the average refractive index Rth can also be calculated from the following equations (A) and (B), based on the assumption values of and the input maximum head value.

[Equation 1]

In addition, Re (θ) above represents a retardation value in a direction inclined at an angle θ from the normal direction. In the above formula, nx represents the refractive index in the slow axis direction in the plane, ny represents the refractive index in the direction orthogonal to nx in the plane, and nz represents the refractive index in the direction orthogonal to nx and ny. . d represents the thickness of the measuring film.

〔Long liquid crystal film〕

The long liquid crystal film of the present invention has a long substrate, a long optical alignment layer, and a long liquid crystal layer having an in-plane retardation in this order. The long liquid crystal film will be described in detail below. In addition, about the physical property value, such as a phase difference value and thickness mentioned later, it shall be in the part normally provided for subsequent use (typically the center area of the width direction with respect to the width direction).

1 is a conceptual diagram showing an example of a first embodiment of a long liquid crystal film of the present invention. This elongate liquid crystal film (which is also simply referred to as a liquid crystal film) 10 is a long elongated substrate (also referred to as a long substrate or simply substrate) 1, and a long optical alignment layer (which is also simply referred to as a light alignment layer) (2) , A long liquid crystal layer (also simply referred to as a liquid crystal layer) 3 is provided in a long shape in this order. Although the base material 1, the photo-alignment layer 2, and the liquid crystal layer 3 are drawn in an equal width, in practice, the base material 1 has a wider width than the photo-alignment layer 2, and a liquid crystal layer. (3) is generally provided to be narrower than the photo-alignment layer 2. However, if necessary, the liquid crystal layer 3 may be provided to be wider than the photo-alignment layer 2 and narrower than the support substrate 1.

Here, in the long liquid crystal film of the present invention, in the liquid crystal layer, when the long liquid crystal film is sandwiched by a linear polarizer and a spectrometer and placed at a quenching position to irradiate light, a stripe-shaped region where light leakage occurs is present. , The slow axis fluctuation Δβ in the striped region is greater than 0 ° and less than 0.04 °. This point will be described in detail later.

In the long liquid crystal film of the present invention, at least Re (550) may have an in-plane retardation of 10 nm or more. Preferably, Re (550) is in the range of 100 nm to 250 nm, and in this range, it can be used as various optical compensation films or wave plates. More preferably, Re (550) is in the range of 120 nm to 160 nm, and in this range, it can be used as a λ / 4 wave plate.

Moreover, it is preferable that the in-plane retardation at each wavelength satisfies the following relationship with respect to the in-plane retardation of the long liquid crystal film.

Re (450) / Re (550) <1.0

1.0 <Re (650) / Re (550)

If this relationship is satisfied, uniform polarization conversion is possible over a wide band, and when used as a variety of optical compensation films or wave plates, good performance with little color change can be exhibited.

<Long description>

The long base material 1 can be applied to a long body of various transparent film materials such as TAC (triacetyl cellulose) film, acrylic film, polycarbonate film, cycloolefin film, polyethylene terephthalate film, transparent film material made of glass, and the like. . It is preferable that it is a resin film from a viewpoint of combining strength and flexibility. The elongate substrate 1 may be a transparent film material that is optically isotropic from the viewpoint of optical design of the entire liquid crystal film or optical alignment suitability described later.

The thickness of the long substrate 1 is not limited, and the thickness capable of holding the photo-alignment layer 2 and the liquid crystal layer 3 depending on the use of the long liquid crystal film 10 and the material for forming the long substrate 1 You may set appropriately.

The thickness of the long substrate 1 is preferably 1 to 250 μm, more preferably 3 to 150 μm, and even more preferably 5 to 50 μm.

Moreover, the long base material 1 preferably has a transmittance of 50% or more, more preferably 70% or more, and even more preferably 85% or more with respect to light acting by the liquid crystal layer 3.

<Optical alignment layer>

The photo-alignment layer 2 is formed on the surface of the long substrate 1. The photo-alignment layer 2 is an alignment film for aligning the liquid crystal compound in a predetermined alignment pattern when exerting an alignment regulating force and forming a liquid crystal layer. The photo-alignment layer 2 is made of an alignment film by irradiating polarized light to a material having a photo-alignment property.

As will be described later, the photo-alignment layer 2 is formed by coating and drying a coating liquid on the photo-alignment layer, and then forming a material layer on the photo-alignment layer on the substrate 1, followed by irradiation of linearly polarized ultraviolet light. Is formed by.

The polarization can be irradiated from the vertical direction or the inclined direction with respect to the material layer.

As the material for the photo-alignment layer 2 (photo-alignment material), various materials to which the method of photo-alignment can be applied can be applied. As a preferred embodiment, it is possible to use, for example, light dimerization materials, in particular compounds containing cinnamic acid derivatives. Moreover, photoisomerization materials, such as azo compounds, photodegradable materials, etc. can also be used conveniently.

As described later, the long liquid crystal film 10 is cured in a state in which the liquid crystal material with respect to the liquid crystal layer 3 is aligned by the alignment regulating force of the photo-alignment layer 2 to produce the liquid crystal layer 3.

The thickness of the photo-alignment layer 2 is not limited, and the thickness at which the necessary orientation function is obtained may be appropriately set depending on the material for forming the photo-alignment layer 2.

The thickness of the photo-alignment layer 2 is preferably 0.01 μm to 5 μm, and more preferably 0.05 μm to 2 μm.

<Liquid crystal layer>

The liquid crystal layer 3 is coated with a corresponding coating liquid (polymerizable liquid crystal composition) by a coating head such as a die, then dried, and then irradiated with ultraviolet light to cure, thereby aligning the photoalignment layer 2 It is produced by solidifying (curing) the liquid crystal material in an aligned state by the regulating force. The in-plane retardation of the liquid crystal layer 3 can be adjusted according to the refractive index anisotropy Δn of the liquid crystal material used to achieve the desired value, alignment control, and the film thickness of the liquid crystal layer. Typically, the in-plane retardation Re (550) is in the range of 100 to 250 nm, and preferably in the range of 120 to 160 nm if it is used as a quarter wave plate.

Moreover, with respect to the in-plane retardation of the liquid crystal layer 3, it is preferable that the in-plane retardation at each wavelength satisfies the following relationship.

Re (450) / Re (550) <1.0

1.0 <Re (650) / Re (550)

If this relationship is satisfied, uniform polarization conversion is possible over a wide band, and when used as a variety of optical compensation films or wave plates, good performance with little color change can be exhibited.

In the present invention, when the long liquid crystal film 10 including the liquid crystal layer 3 is sandwiched by a linear polarizer and a spectrometer and placed in a quenching position to irradiate light, the liquid crystal layer 3 is streaked with light leakage. It is characterized by the presence of a shape region, wherein the slow axis fluctuation in this stripe shape region is greater than 0 degrees and less than 0.04 degrees. Typically, in the liquid crystal layer 3, such a slow axis fluctuation region occurs in a stripe shape, and the slow axis fluctuation Δβ in the region is greater than 0 degrees and is less than 0.04 degrees. The slow axis variation Δβ referred to here is the maximum value of the angle β of the slow axis of the region with respect to the average slow axis direction α of the liquid crystal layer 3.

Δβ = (maximum value in the region of | β |)

Here, the light leakage amount in the stripe-shaped region is changed by Δβ. When the Jones matrix is calculated, the light leakage amount when a phase difference film is inserted in cross nicol is represented by I × {sinθ × cosθ × (1 -exp [2πi × A / λ])} ² . (I: the intensity of the light source, θ: the deviation angle of the slow axis from the absorption axis of the polarizer or the analyzer, A: Re, λ: wavelength of the light source). When the average slow axis direction α is inserted parallel or perpendicular to the absorption axis of the polarizer, the light leakage amount becomes zero, and Δβ has a maximum value of 45 ° ± 90 × n.

The above formula ignores "scattering" "absorption" and "reflection". Therefore, when the alignment of the liquid crystal is poorly scattered, light is always leaked even if the film is rotated. On the other hand, light leakage in the stripe-shaped region of the present application can be distinguished because light leakage is suppressed by adjusting β to the absorption axis of the polarizer.

Here, the average slow axis direction α of the liquid crystal layer 3 is a slow axis value (angle in the direction of the ground axis) determined by the above-described KOBRA 21ADH as an average value taken at arbitrary 10 points of the film, and the above-mentioned quenching position. Is set based on the average slow axis direction α.

Note that the slow axis value β of the stripe-shaped region is a slow axis value (angle in the direction of the ground axis) determined by the above-described KOBRA 21ADH in the stripe-shaped region. Within one stripe-shaped region, a slow axis value β at an arbitrary 10 points in the longitudinal direction of the stripe-shaped region is obtained, and Δβ can be obtained by the above formula using the maximum value.

Note that the slow axis value may be obtained based on an arbitrary direction in the plane of the liquid crystal layer 3. Therefore, the slow axis value β (= Δβ) of the stripe-shaped region may be determined based on the average slow axis direction of the liquid crystal layer 3.

The inventors, in improving the quality of the liquid crystal film including the photo-alignment layer, have defects caused by foreign matters found in the prior art, or fine streak-like irregularities (striped shapes) different from a wide range of phase difference non-uniformities due to variations in manufacturing conditions. Area). As a result of the analysis, the unevenness of these stripe shapes does not involve foreign matter or film thickness fluctuation, and the slight slow axis in the fine region is misaligned with the average slow axis direction of the liquid crystal film. It was understood that it was recognized as. This streak-like nonuniformity could not be reduced by the conventionally known defect suppression technology or non-uniformity suppression technology.

In addition, the stripe shape referred to herein is a concept that broadly includes not only a straight line shape but also a complicated curved shape or a plurality of lines overlapping to show a radial or brush shape. The width per stripe-shaped area is approximately 0.1 mm to 1 mm, but when a large number of stripes are collected, the width may be larger than that of visual recognition. The length of the stripe-shaped region is irregular, and in some cases, from about 1 mm, the long one may reach several tens of meters.

In order to explain in more detail, a practical example will be described. Fig. 6 is a failure (phase difference non-uniformity) actually observed in a long liquid crystal film before improvement (Comparative Example 2 to be described later). Fig. 7 shows the results of measuring the in-plane retardation and the slow axis direction at 0.5 mm intervals so that the image indicated by the arrow is a stripe-shaped region and traverse the stripe-shaped region (along the white line in the figure). In the stripe-shaped region, the slow axis is shifted and Δβ reaches a maximum of 0.10 °. In addition, the image shown in FIG. 6 was taken with the long liquid crystal film sandwiched between a linear polarizer and an analyzer, and placed in a quenching position. The vertical direction of the batch image shown in FIG. 6 is the width direction of the long liquid crystal film, and the line drawn to the left and right of the image originates from image processing of the imaging device. Further, the arc-shaped line is a marking mark written on the film in order to specify a stripe-shaped area at the time of measurement.

8 is an image of another stripe-shaped region (Comparative Example 1 to be described later). A straight stripe-shaped area is generated from an arrow other than the image toward the left. The results of the same measurements as in FIG. 6 are shown in FIG. 9 to traverse this area (along the white line in the drawing). Although the maximum value of [Delta] [beta] is slightly over 0.04 [deg.], This stripe-shaped region extends over several tens of meters in the longitudinal direction of the long liquid crystal film, and the circularly polarizing plate is cut using a liquid crystal film piece cut to include this stripe-shaped region. By manufacturing and evaluating the light leakage of the reflected light, it was possible to visually recognize the light leakage corresponding to the striped region. Moreover, the vertical direction of an image is the width direction of a long liquid crystal film. It is clear that the portion enclosed by the arc is a defect caused by a foreign material, and has a completely different appearance (showing a characteristic star-shaped appearance) from the stripe-shaped region defined in the present invention.

The long liquid crystal film of the present invention has a slow axis variation Δβ greater than 0 ° and less than 0.04 ° in such a stripe-shaped region.

By setting it as such a structure of this invention, the phase difference nonuniformity of a liquid crystal layer can be suppressed, and when a liquid crystal film is mounted on a display device etc., it can prevent that the unevenness of a stripe shape is recognized visually.

The long liquid crystal film of the present invention having a slow axis variation Δβ in the stripe-shaped region of the liquid crystal layer greater than 0 ° and less than 0.04 ° supports the long substrate in the photo-alignment step when forming the photo-alignment layer. It can be produced by suppressing local polarization change caused by reflected light from the backup roll. The manufacturing method of the long liquid crystal film of this invention is explained in full detail later.

Here, from the viewpoint of suitably suppressing the phase difference non-uniformity of the liquid crystal layer, the slow axis variation Δβ in the stripe-shaped region is preferably 0.01 ° to 0.04 °, more preferably 0.01 ° to 0.03 °, and more preferably 0.01 ° to 0.02 ° is more preferable.

Moreover, when a liquid crystal film is mounted on a display device or the like, the width of the stripe-shaped region is preferably 0.1 mm to 2 mm, and from 0.1 mm to 1 mm, from the viewpoint of suitably suppressing the recognition of streak-like irregularities with the naked eye. Is more preferable, and 0.1 mm to 0.5 mm is more preferable.

Similarly, the length of the stripe-shaped region is preferably 2 mm to 20 mm, more preferably 2 mm to 10 mm, and further preferably 2 mm to 5 mm.

Moreover, when a liquid crystal film is mounted on a display device or the like, the ratio of the total area of the stripe-shaped area to the area of the surface of the liquid crystal layer from the viewpoint of appropriately suppressing the recognition of unevenness of the stripe-like shape is visually observed. 6% or less is preferable, 1% to 4% is more preferable, and 1% to 3% or less is more preferable.

In addition, the ratio of the total area of the stripe-shaped area to the area of the surface of the liquid crystal layer is measured at Δβ at 0.5 mm intervals in the width direction and the lengthwise direction in five arbitrary areas of 20 mm × 30 mm, and Δβ> The width and length of the stripe-shaped region are calculated using a region of 0.01 degrees as a stripe-shaped region. It is an average value by measuring the area of a stripe-shaped area present in each area, and calculating the ratio of the stripe-shaped area for each area. The method of measuring Δβ will be described later.

In addition, the width, length, and area of the stripe-shaped region may be measured in a state where the long liquid crystal film is sandwiched by a linear polarizer and a spectrometer and placed in a quenching position to irradiate light.

[Polymerizable liquid crystal composition]

The liquid crystal layer 3 can be prepared by applying various polymerizable liquid crystal compositions that are liquid crystal materials that exhibit optical anisotropy. Here, the polymerizable liquid crystal composition exhibits liquid crystallinity, and in addition to the polymerizable liquid crystal compound having a polymerizable functional group in the molecule, other polymerizable compounds, alignment stabilizers, solvents, and the like can be contained.

(Polymerizable liquid crystal compound)

The polymerizable liquid crystal compound related to the liquid crystal layer 3 has a refractive index anisotropy, and has a function of providing desired retardation property by arranging regularly by the alignment regulating force of the photo-alignment layer 2. As a polymerizable liquid crystal compound, materials showing a liquid crystal phase, such as a nematic phase and a smectic phase, are mentioned, for example. Further, polymerizable liquid crystal molecules having various structures such as rod-like liquid crystal compounds and disc-like liquid crystal compounds can be used.

As a polymerizable liquid crystal compound used in the present embodiment, Japanese Patent Application Laid-open No. Hei 8-050206, Japanese Patent Application Publication No. 2007-002220, Japanese Patent Application Publication No. 2010-244038, Japanese Patent Application Publication No. 2008-019240, Japanese Patent Application Publication No. 2013-166879, Japanese Patent Application Publication No. 2014-078036, Japanese Patent Application Publication No. 2014-198813, Japanese Patent Application Publication No. 2011-006360, Japanese Patent Application Publication No. 2011-006361, Japanese Patent Application Publication No. 2011 -207765, Japanese Patent Application Publication No. 2008-273925, Japanese Patent Publication No. 2015-200877, etc. can be used. A plurality of different polymerizable liquid crystal compounds can be mixed and used from the viewpoint of adjusting the phase transition temperature or suppressing crystallization of the polymerizable liquid crystal compound to obtain a more excellent liquid crystal film.

(Other polymerizable compounds)

Other polymerizable compounds can be added to the polymerizable liquid crystal compound related to the liquid crystal layer 3. Preferably, a non-liquid crystal polyfunctional polymerizable compound is added. As such a non-liquid crystal polyfunctional polymerizable compound, well-known polyhydric alcohols and ester compounds of (meth) acrylic acid are mentioned. The liquidity of the polymerizable liquid crystal composition is increased by the addition of these compounds, and leveling is promoted, so that the liquid crystal layer 3 with less phase difference nonuniformity can be obtained. Further, the wet heat durability of the liquid crystal layer 3 can be improved, and the scratch resistance and film strength can also be increased.

(Orientation stabilizer)

An alignment stabilizer can be added to the polymerizable liquid crystal compound related to the liquid crystal layer 3. By the addition of the alignment stabilizer, various disturbance factors are suppressed and the alignment of the liquid crystal composition is stabilized, whereby the liquid crystal layer 3 with little retardation unevenness can be obtained. Moreover, the orientation of a liquid crystal layer can be adjusted to arbitrary orientations, such as horizontal orientation, vertical orientation, hybrid orientation, and cholesteric orientation, by suitably selecting the structure of an alignment stabilizer. From the standpoint of achieving both orientation stabilization and leveling, particularly preferably, an acrylic polymer having a fluoroaliphatic side chain (paragraphs 0022 to 0063 of JP 2008-257205 A, paragraphs 0017 to 0124 of JP 2006-091732 A) It is possible to add).

(Polymerization initiator)

The polymerization initiator is contained in the polymerizable liquid crystal compound related to the liquid crystal layer 3. Various polymerization initiators can be selected according to the polymerizable group of the polymerizable liquid crystal compound. Preferably, the polymerizable liquid crystal compound is a (meth) acrylate compound, and the polymerization initiator is a radical polymerization initiator. As such a polymerization initiator, various well-known polymerization initiators can be used. In order to achieve a uniform orientation, it is preferable that the coating solution has excellent stability over time and core hardenability of the coating film, and from that viewpoint, an oxime ester compound (US Patent Publication No. 4,255,513, Japanese Patent Publication No. 2001-233842) ) And acylphosphine oxide compounds (described in Japanese Patent Application Laid-open No. Hei 5-029234, Japanese Patent Laid-Open No. Hei 10-095788, Japanese Patent Laid-Open No. Hei 10-029997, etc.) are suitably used.

(menstruum)

As the solvent, various known solvents can be used. When selecting a solvent, it is preferable to select in consideration of the solubility of the polymerizable liquid crystal compound and other components, and wettability and volatilization with respect to the support of the coating liquid. By appropriately selecting a solvent, a uniform and non-uniform coating film can be formed, and the liquid crystal film 10 in which phase difference unevenness is suppressed can be obtained.

[Production Method for Long Liquid Crystal Film]

The manufacturing method (also called the manufacturing method of the present invention) of the long liquid crystal film of the present invention,

While conveying the long substrate in the longitudinal direction, it has a photo-alignment step of irradiating ultraviolet rays to the material layer to be a photo-alignment layer formed on the long substrate,

In the photo-alignment process, when irradiating ultraviolet rays to the material layer, the surface opposite to the surface on which the material layer of the long base material is formed is supported by the backup roll,

The maximum height roughness Rz of the surface of a backup roll is a manufacturing method of 0.7 nm or less.

Moreover, it is preferable that the ultraviolet reflectance of the surface of a backup roll is 10% or less.

Hereinafter, an example of the manufacturing method of the elongate liquid crystal film of this invention is demonstrated.

The manufacturing method of a long liquid crystal film,

Each of the following steps is performed while conveying the long base material 1 in the longitudinal direction.

A first coating step of forming a material layer by coating a coating liquid that becomes a photo-alignment layer on a long substrate.

A drying step of heating and drying the material layer coated on the long substrate.

A photo-alignment step of curing a material layer formed on a long substrate by irradiating with ultraviolet rays.

A second coating step of forming a composition layer by coating a liquid crystal composition to be a liquid crystal layer on the optical alignment layer formed by the photo-alignment step from the coating step.

A heating step of heating the coating layer to promote alignment of the liquid crystal material in the composition layer.

A curing step of curing the heated composition layer by irradiating ultraviolet rays.

In the above manufacturing method, by performing each of the above steps in order, the elongated light alignment layer 2 and the elongated liquid crystal layer 3 are formed on the elongate substrate 1 to produce the elongated liquid crystal film 10.

Hereinafter, the manufacturing method of the long liquid crystal film of this invention is demonstrated more concretely using the example of the manufacturing apparatus which manufactures a long liquid crystal film by performing each said process.

3 is a schematic view showing a main part of an example of a manufacturing apparatus that performs the above method for producing a long liquid crystal film.

The manufacturing apparatus 30 shown in FIG. 3 forms a photo-alignment layer 2 and a liquid crystal layer 3 by roll-to-roll, and the rotating shaft which loads the roll 31 formed by winding the long base material 1 60, a winding shaft 61 for winding the long liquid crystal film 10 after production, and a die 32 and a heating device 33 provided in a conveyance path from the rotation shaft 60 to the winding shaft 61 ), Light source 34 and backup roll 38, die 35, heating device 36, and light source 37.

The manufacturing apparatus 30 carries out the 1st coating process with the die 32, conveying the elongate base material 1 from the rotating shaft 60 to the winding shaft 61 in a longitudinal direction, and drying it with the heating apparatus 33 A process is performed, a photo-alignment process is performed with a light source 34, a second coating process is performed with a die 35, a heating process is performed with a heating device 36, and a curing process is performed with a light source 37.

First, the roll 31 formed by winding the long base 1 is loaded on the rotating shaft 60, the long base 1 is pulled out from the roll 31, and the die 32, the heating device 33, and the light source 34 and, through the backup roll 38, the die 35, the heating device 36, and the light source 37 are passed through a predetermined conveyance path to the winding shaft 61.

The die 32 is supplied with a coating solution serving as the photo-alignment layer 2. Moreover, the liquid crystal composition used as the liquid crystal layer 3 is supplied to the die 35.

The heating device 33 and the heating device 36 are each driven to a predetermined temperature. Further, the light source 34 and the light source 37 are driven to irradiate light of a predetermined light amount and wavelength, respectively.

When the conveyance of the long base material 1 is started in this state, the long base material 1 is conveyed to the position of the die 32, and the coating liquid used as the light-direction layer 2 is coated by the die 32 to form a material layer This is formed (first coating process).

In addition, the coating method (coating method) of the coating liquid used as the photo-alignment layer 2 is not limited to the above-mentioned die coating method, and the dip coating method, air knife coating method, curtain coating method, roller coating method, wire bar Various known methods, such as a coat method and a gravure coat method, can be used.

Subsequently, the elongate base material 1 is conveyed to the position of the heating device 33, and the material layer coated by the heating device 33 is dried and heated (drying step).

Heating and drying by the heating device 33 may be performed by a known method of heating and drying a sheet-like object. For example, warm air heating, heating by a heat roller, etc. are mentioned.

Next, the elongate substrate 1 is conveyed to the positions of the light source 34 and the backup roll 38, and the material layer is cured by irradiation of ultraviolet light by linear polarization from the light source 34 (light alignment process). . Here, a desired alignment regulating force can be expressed by irradiating a linearly polarized light to the material layer serving as the photo-alignment layer 2.

The light source 34 is not particularly limited, and various light sources for irradiating light having a wavelength corresponding to a material for forming an alignment film can be used. From the viewpoint of eliminating the unevenness of the orientation regulating force of the photo-alignment layer 2, it is preferable to use the light source 34 having a lightness variation in the width direction and a light polarization degree variation.

By the above, the photo-alignment layer 2 is formed on the elongate base material 1, and is conveyed to the position of the die 35 again.

Here, in the manufacturing method of the long liquid crystal film of this invention, the photo-alignment process is performed in the state which the surface opposite to the surface in which the material layer of the long base material 1 was formed is supported by the backup roll 38. If the long substrate 1 is not supported during the photo-alignment process, the long substrate 1 fluctuates, the distance from the light source 34 fluctuates, and the in-plane distribution of the orientation regulating force of the formed photo-alignment layer 2 changes. Non-uniformity occurs. For this reason, the photo-alignment process is performed in a state in which the long base 1 is supported by the backup roll 38.

The present inventors have found that, when the long alignment substrate is transported in the longitudinal direction, the light alignment layer and the liquid crystal layer are formed, fine streak-like irregularities (striped region) occur in the liquid crystal layer. When this point was further studied, it was attributable to the surface properties of the backup roll supporting the long base material 1 in the photo-alignment process, in that streak-like regions were periodically generated in the longitudinal direction of the produced long liquid crystal film. I could see.

Part of the light irradiated from the light source 34 and incident on the material layer serving as the photo-alignment layer 2 is reflected by the backup roll 38 and again enters the material layer. At this time, if scratches and / or foreign matter adhere to the surface of the backup roll 38, the polarization state of the reflected light reflected by the backup roll 38 is changed locally at the position where the scratches or the like are present. For this reason, local non-uniformity in the direction of the orientation regulating force is generated in the photo-alignment layer 2 to be formed, whereby fine streak-like non-uniformity (striped region) is formed in the liquid crystal layer 3 formed on the photo-alignment layer 2. ).

On the other hand, in the manufacturing method of the present invention, by setting the maximum height roughness Rz of the surface of the backup roll 38 to 0.7 μm or less, the local polarization state of the reflected light from the backup roll 38 when performing the photo-alignment treatment is By suppressing the change and improving the streak-like non-uniformity (striped region) generated in the liquid crystal layer, the slow axis fluctuation Δβ in the streak-shaped region can be suppressed to a range greater than 0 degrees and less than 0.04 degrees. In addition, by suppressing the change in the localized polarization state, the slow axis fluctuation Δβ of the streaked region present in the liquid crystal layer was suppressed to less than 0.04 °, and as a result, unevenness of the streak shape was observed with the naked eye in the mounted state with the image display device. You can make it unrecognizable.

The maximum height roughness Rz of the surface of the backup roll 38 is preferably 0.7 μm or less, more preferably 0.6 μm or less, and even more preferably 0.5 μm or less.

The maximum height roughness Rz of the surface of the backup roll 38 is measured by a method conforming to JIS B0601 (2001) using a surface roughness meter (trade name SJ-310, manufactured by Mitsutoyo Co., Ltd.).

The state of the photo-alignment layer in the photo-alignment process is extremely fine, and it is impossible to quantitatively grasp the in-plane distribution. On the other hand, since the liquid crystal layer oriented by the orientation-regulating force exhibits large retardation, some orientation-regulating force Can cause large optical non-uniformity. The inventors, when incident on a long substrate and a material layer from a polarized light source and transmitted through and reflected on a back-up roll, enter the material layer again in a state where a localized polarization change occurs, thereby preventing a non-uniformity of the orientation regulating force other than assumed in the light alignment layer. This phenomenon is based on the hypothesis of generating, and as a result, a uniform thickness of both the photo-alignment layer and the liquid crystal layer and a defect that can be recognized by causing a local slow axis shift in the liquid crystal layer without involving foreign matter. Various measures that can be suppressed have been studied, and the present invention has been realized.

Here, for example, the backup roll 38 may be subjected to mirror surface processing or light absorption processing such as blackening so that the reflected light from the backup roll 38 is uniform without any irregularity. From the viewpoint of effectively using the irradiated light, it is preferable to use a mirror-surface processing, and it is preferable to use a smooth back-up roll that does not have a site where no diffuse reflection or bright spots are generated when the reflected light is visually confirmed by shooting light across the width direction. In order to confirm whether the surface state of a suitable backup roll is used, a method of detecting and removing a portion where polarization cancellation occurs by irradiating green polarized light having high visibility and observing the reflected light through a linear polarizer can be used.

Moreover, when the backup roll 38 is a mirror surface, it is preferable to use the long substrate 1 having high transparency and being optically isotropic so that reflected light from the backup roll, scratches on the roll, and scattered light from foreign matter are not polarized. It is one aspect. Specifically, the in-plane retardation Re (550) of the long substrate 1 is preferably 10 nm or less, more preferably 5 nm or less, and even more preferably 3 nm or less. Moreover, the thickness direction retardation Rth (550) is preferably in the range of -20 to 20 nm, and more preferably in the range of -10 nm to 10 nm. Within this range, the polarization reflected from the backup roll 38 in a direction other than specular reflection also enters the optical alignment layer 2 again without polarization conversion, and the orientation of the alignment control force of the optical alignment layer 2 is uneven. This can be suppressed from occurring, and an effective orientation regulating force can be provided with a small irradiation amount.

Moreover, the reflectance (ultraviolet reflectance) of the surface of the backup roll 38 with respect to ultraviolet rays irradiated in the photo-alignment process is preferably 10% or less, more preferably 5% or less, and further preferably 2% or less.

By setting the ultraviolet reflectance of the surface of the backup roll 38 to 10% or less, it is possible to suppress the reflected light having a locally changed polarization state from entering the material layer again.

The reflectance of the surface of the backup roll was measured using a spectrophotometer (MV-3100, manufactured by Nippon Bunko Co., Ltd.), and the front reflectance for light with a wavelength of 365 nm was used.

In the manufacturing apparatus 30, the long base material 1 on which the photo-alignment layer 2 is formed is conveyed to the position of the die 35, and the liquid crystal composition that becomes the liquid crystal layer 3 by the die 35 is photo-aligned. It is coated on the layer 2 to form a composition layer. At this time, the liquid crystal material in the composition layer is oriented by the alignment regulating force of the photo-alignment layer 2.

In addition, the coating method (coating method) of the liquid crystal composition used as the liquid crystal layer 3 is not limited to the above-described die coating method, and the dip coating method, air knife coating method, curtain coating method, roller coating method, wire bar coating Various known methods, such as the method and the gravure coat method, can be used.

Next, the elongate base material 1 is conveyed to the position of the heating device 36, and the composition layer coated by the heating device 36 is heated and dried. Although not shown, the orientation of the liquid crystal material in the composition layer can be promoted and adjusted by the heating device 36.

Heating and drying by the heating device 36 may be performed by a known method of heating and drying a sheet-like object. For example, warm air heating, heating by a heat roller, etc. are mentioned.

Subsequently, the elongate substrate 1 is conveyed to the position of the light source 37, the ultraviolet light is irradiated by the light source 37, and the composition layer is in a state in which the liquid crystal material is aligned by the alignment regulating force of the light alignment layer 2 Is cured to prepare a liquid crystal layer 3.

Here, the irradiation of the ultraviolet rays is performed from the composition layer side, whereby the composition layer is efficiently irradiated with ultraviolet rays to produce the liquid crystal layer 3.

Further, the light source 37 is not particularly limited, and various light sources irradiating light having a wavelength corresponding to the material for forming the liquid crystal layer can be used.

The elongated liquid crystal film 10 produced in this way is conveyed to the winding shaft 61 and wound up on the roll 39.

This roll 39 can also be provided for other processes. For example, the polarizing plate described later can be produced in roll-to-roll by being conveyed to the manufacturing apparatus 40 for laminating the linear polarizing plate described later and the long liquid crystal film 10.

〔Image display device and optical parts〕

The long liquid crystal film of the present invention can be used as an optical component that can be used in various image display devices by combining with a linear polarizing plate. Moreover, an image display device excellent in display quality can be constructed by appropriately cutting and mounting the image display device. In combination, various adhesives can be used for bonding. Examples of such adhesives include ultraviolet curable resins, thermosetting resins, and pressure-sensitive adhesives.

<Long polarizing plate>

By stacking the long liquid crystal film 10 of the present invention in alignment with the linear polarizer 21 and the longitudinal direction of each other, the long polarizing plate (also simply referred to as a polarizing plate) 20 can be configured (see FIG. 2). For example, when the long polarizing plate is configured as a circular polarizing plate, the in-plane retardation of the long liquid crystal film (and liquid crystal layer) of the present invention is preferably in the range of 110 to 160 nm, more preferably in the range of 130 to 150 nm.

Moreover, it is preferable to arrange | position the slow axis of the long liquid crystal film (and liquid crystal layer) of this invention so that it may become 45 degrees with the absorption axis (transmission axis) of a linear polarizing plate. By setting the slow axis of the long liquid crystal film of the present invention to 45 ° with respect to the longitudinal direction, that is, the conveying direction, a long linear polarizer having an absorption axis (transmission axis) in the width direction (that is, the absorption axis is the longitudinal direction of the linear polarizer) With respect to 90˚), or a long linear polarizer having an absorption axis (transmission axis) in the conveying direction (longitudinal direction) (that is, the absorption axis is 0˚ with respect to the longitudinal direction of the linear polarizing plate) and a roll-to-roll process. You can manufacture a long-sized circular polarizing plate.

The linear polarizing plate 21 is not limited, and a known linear polarizing plate can be used.

For example, the linear polarizing plate 21 is configured by sandwiching the optical functional layer serving as a linear polarizing plate with a pair of substrates. Here, the base material is a transparent film made of TAC (triacetylcellulose), an acrylic resin such as methyl poly (meth) acrylate or a copolymer thereof, a crosslinked polymer resin such as an epoxy compound or a (meth) acrylate compound, a cycloolefin resin, Resins, such as polycarbonate resin, glass, etc. can be used. You may use the long base material of the long liquid crystal film of this invention as such a base material, and may be laminated | stacked in order of an optical functional layer, a long base material 1, the photo-alignment layer 2, and the liquid crystal layer 3. The optical functional layer is typically produced by adsorbing and aligning iodine compound molecules on a film material by polyvinyl alcohol (PVA), but other films using organic dichroic dyes instead of iodine compound molecules, organic dichroic dyes May be used, a layer in which a liquid crystal composition is blended and aligned, a layer in which a liquid crystal organic dichroic dye is aligned, or the like. As the adhesive layer 22 (not shown) for lamination, various known adhesives described above can be used.

4 is a diagram schematically showing a main part of a manufacturing apparatus that performs a process of manufacturing a long polarizing plate 20 by laminating a long liquid crystal film 10 and a long linear polarizing plate 21. In this manufacturing apparatus 40, the long liquid crystal film 10 is provided as the roll 39 in the rolled state. Moreover, the linear polarizing plate 21 (laminated body) laminated | stacked the adhesive film 22 and the peeling film 41 which consists of PET films is supplied as the roll 42 in the rolled state.

The roll 39 and the roll 42 are respectively loaded on predetermined rotation shafts 47 and 48 for delivery. The roll 42 is loaded so that the release film 41 is on the surface side.

A predetermined conveying path from the roll 39 loaded on the rotational axis 47 to the winding axis 49 where the long liquid crystal film 10 is pulled out and the long liquid crystal film 10 on which the linear polarizing plate 21 is stacked is wound up. Is passed through. The pressure roll 45 is arrange | positioned in the middle of the conveyance path of the long liquid crystal film 10.

Moreover, the laminated body is taken out from the roll 42 loaded on the rotating shaft 48 and passes through the pressing roll 45 and passes through a predetermined conveyance path to the winding shaft 49. Moreover, in the middle of the path from the rotating shaft 48 to the pressure roll 45, the release roll 43 for peeling the release film 41 from the laminated body is disposed, and the release film 41 is provided with a release roll 43 ), And is passed through a predetermined conveyance path to the winding shaft 55 that winds up the release film 41.

When the conveyance of each film is started in such a state, the manufacturing apparatus 40 pulls out the laminated body of the linear polarizing plate 21, the adhesive layer 22, and the release film 41 from the roll 42, while the release roll ( The peeling film 41 is peeled off by 43), and the peeled peeling film 41 is wound up on the roll 44. Moreover, while drawing out the liquid crystal film 10 from the roll 39, the liquid crystal film 10 and the release film 41 of the linear polarizing plate 21 and the adhesive layer 22 after peeling by the pressure roll 45 are removed. The laminate is laminated and pressed, thereby producing a laminate of the liquid crystal film 10, the adhesive layer 22, and the linear polarizing plate 21 (ie, the polarizing plate 20). Then, the laminated body of the liquid crystal film 10, the adhesive layer 22, and the linear polarizing plate 21 is conveyed to the winding axis 49, and this laminated body is wound up on the roll 48.

Then, other layers, such as an adhesive layer and a separator film (not shown), may be suitably arrange | positioned in the polarizing plate 20 according to a use. Moreover, the elongate polarizing plate 20 can be cut into a desired size to form a single-leaf polarizing plate, and can be applied to an image display device or the like.

Moreover, in the example shown in FIG. 2, although the linear polarizing plate 21 was set as the structure laminated | stacked on the elongate base material 1 side of the liquid crystal film 10, it is not limited to this, It is laminated | stacked on the liquid crystal layer 3 side. It may be configured.

Moreover, although the manufacturing apparatus 40 shown in FIG. 4 is shown as an example of the manufacturing apparatus which performs the process of laminating the elongate liquid crystal film 10 and the elongate linear polarizing plate 21, and manufacturing the elongate polarizing plate 20, to this It is not limited, and various well-known manufacturing apparatuses and processes for laminating elongate film-like objects can be used.

In addition, in the above description, after manufacturing the long polarizing plate 20 in which the long liquid crystal film 10 and the long linear polarizing plate 21 are laminated, the sheet-shaped polarizing plate is cut out from the long polarizing plate 20. It is not limited to, After cutting the sheet-like liquid crystal film from the long liquid crystal film 10, a sheet-like linear polarizing plate may be laminated to produce a sheet-like polarizing plate.

<Image display device>

5 is a diagram showing an example of the image display device of the present invention. In the image display device 50, an anti-reflection film 52 for preventing internal reflection light is provided on the panel surface (viewer side) of the image display panel 51 as a circular polarizing plate. Here, the image display panel 51 is, for example, an organic EL panel, and displays a desired color image. In addition, the image display panel 51 is not limited to an organic EL panel, and various image display panels such as a liquid crystal display panel can be widely applied.

The antireflection film 52 is typically affixed to the panel surface of the image display panel 51 by the adhesive layer 53 and held. The antireflection film 52 is configured by laminating and integrating the liquid crystal film 10 having the characteristics of the linear polarizing plate 21 and the λ / 4 wave plate by an adhesive layer 22. As the adhesive layer 53, a known adhesive can be used in the same manner as the adhesive layer 22.

<Other optical parts>

The elongate liquid crystal film of the present invention is not limited to a circularly polarizing plate, and can be applied to various optical components. For example, it is a polarizing plate with an optical compensation layer of a liquid crystal display device, a polarizing sunglasses, a brightness improving plate, a decorating film, a viewing angle limiting film, a dimming film, an anti-glare film, and the like. The optical characteristics and the average slow axis direction of the elongated liquid crystal film of the present invention can be variously changed in accordance with the use without departing from the spirit of the present invention.

[Second Embodiment]

As a second embodiment of the elongated liquid crystal film of the present invention, the substrate 1 is peeled and transferred to the laminate of the liquid crystal layer 3 and the photo-alignment layer 2 as a support for easy peeling, or in close contact with the substrate 1 The prepared photo-alignment layer 2 can be applied to the liquid crystal layer 3 as a functional layer in place of the above-described liquid crystal film by peeling and transferring the liquid crystal layer 3 as easy to peel. In this embodiment, the ease of peeling as described above is given to any one layer, and the liquid crystal layer 3 or the laminate of the liquid crystal layer 3 and the photo-alignment layer 2 is replaced with the liquid crystal film 10. Except for the arrangement, the materials and members described in the first embodiment can be used in the same way.

In the second embodiment, since the base material 1 is peeled off and removed, it is possible to use as a base material a film having optical properties that is an obstacle when used as the liquid crystal film 10. As an example, in the process of polarization irradiation in the photo-alignment, when the backup roll is a mirror surface, instead of the optically isotropic long substrate described above, a long retardation film of a high retardation film having an in-plane retardation of 500 nm or more, or It is possible to use a substrate having high light scattering properties, a substrate having light absorption properties, and the like. These films have a function of resolving polarization and absorbing light, thereby resolving the unevenness of the alignment-regulating force of light alignment due to reflected light.

In addition, in the manufacturing process for producing the long liquid crystal film of the second embodiment, except for appropriately providing a step for peeling and removing the substrate 1 or the laminate of the substrate 1 and the photo-alignment layer 2, It can manufacture by the process similar to the manufacturing process of 1st Embodiment.

The elongated liquid crystal layer thus obtained can be transferred to a linear polarizing plate or the like and used as the above-mentioned optical component, particularly preferably a circular polarizing plate. It is apparent that an image display device such as an organic EL display device constructed by using the circular polarizing plate thus obtained can achieve the same display quality as the image display device using the circular polarizing plate containing the liquid crystal film of the first embodiment.

[Other embodiments]

In the first and second embodiments, a case has been described in which the liquid crystal layer 3 has an in-plane retardation, but in the present invention, it is possible to have anisotropy (dichroism) of light absorption in addition to the retardation. That is, a long substrate, a long optical alignment layer, and a long liquid crystal layer are included in this order, and the long liquid crystal layer is a layer exhibiting dichroism from at least part of the infrared region to the visible region, and the liquid crystal layer is in the in-plane direction. It is in the form of a long liquid crystal film having an absorption axis.

In this embodiment, the same concept as in the first and second embodiments can be applied by setting the in-plane phase difference in the above-described first and second embodiments as anisotropy of absorption. That is, the liquid crystal layer described above includes a stripe-shaped absorption axis abnormal region, and the maximum value of the angle formed by the absorption axis direction in the abnormal region relative to the average absorption axis direction of the liquid crystal layer is greater than 0 °. It is a long optical film of less than 0.04˚. The long substrate and the long optical alignment layer can be appropriately selected within a range that does not depart from the concept of the present invention, and the long optical film can be used in various optical components, image display devices, and the like described above.

Example

Hereinafter, the present invention will be described in more detail based on examples. The materials, amount of use, ratio, treatment contents, treatment procedures, etc. shown in the following examples can be appropriately changed without departing from the gist of the present invention. Therefore, the scope of the present invention is not to be interpreted limitedly by the examples shown below.

(Preparation of photo-alignment polymer A)

In a reaction vessel equipped with a stirrer, a thermometer, a dropping funnel, and a reflux cooling tube, 100.0 parts by mass of 2- (3,4-epoxycyclohexyl) ethyl trimethoxysilane, 500 parts by mass of methyl isobutyl ketone, and triethylamine 10.0 parts by mass was introduced and mixed at room temperature. Subsequently, 100 parts by mass of deionized water was added dropwise from the dropping funnel for 30 minutes, and then reacted at 80 ° C for 6 hours while mixing under reflux. After completion of the reaction, the organic phase was taken out, washed with 0.2% by mass aqueous ammonium nitrate solution until the water after neutralization was neutralized, and then the solvent and water were distilled off under reduced pressure to obtain an epoxy-containing polyorganosiloxane. Iv) Obtained as a transparent liquid.

When the 1H-NMR analysis was performed on this epoxy-containing polyorganosiloxane, a peak based on the oxiranyl group was obtained in the vicinity of the chemical shift (δ) = 3.2ppm according to the theoretical strength, and no side reaction of the epoxy group occurred during the reaction. Was confirmed. The weight average molecular weight Mw of this epoxy-containing polyorganosiloxane was 2,200 and the epoxy equivalent was 186 g / mol. This was referred to as photoalignable polymer A.

[Example 1]

(Production of Cellulose Acylate Film 1)

(Production of core layer cellulose acylate dope)

The following composition was put into a mixing tank, stirred, and each component was dissolved to prepare a cellulose acetate solution used as a core layer cellulose acylate dope.

-------------------------------------------------- ----

Core layer cellulose acylate dope

-------------------------------------------------- ----

Cellulose acetate with an acetyl substitution degree of 2.88 100 parts by mass

In the example of Japanese Patent Application Publication No. 2015-227955

Polyester compound B described 12 parts by mass

Compound F below 2 parts by mass

Methylene chloride (first solvent) 430 parts by mass

Methanol (second solvent) 64 parts by mass

-------------------------------------------------- ----

[Formula 1]

(Production of outer layer cellulose acylate dope)

10 parts by mass of the following mat agent solution was added to 90 parts by mass of the core layer cellulose acylate dope, and a cellulose acetate solution used as an outer layer cellulose acylate dope was prepared.

-------------------------------------------------- ----

Matte solution

-------------------------------------------------- ----

Silica particles with an average particle size of 20 nm

(AEROSIL R972, made by Nippon Aerosil Co., Ltd.) 2 parts by mass

Methylene chloride (first solvent) 76 parts by mass

Methanol (second solvent) 11 parts by mass

The above core layer cellulose acylate dope 1 part by mass

-------------------------------------------------- ----

(Production of cellulose acylate film 1)

After filtering the core layer cellulose acylate dope and the outer layer cellulose acylate dope with a filter paper having an average pore diameter of 34 μm and a sintered metal filter having an average pore diameter of 10 μm, the core layer cellulose acylate dope and the outer layer cellulose acylate on both sides thereof The dope was cast on a drum at 20 ° C. from an oil researcher at the same time on three layers (band softener). It was peeled off in a state of approximately 20% by mass of the solvent content, and fixed at both ends in the width direction of the film with a tenter clip, and dried while stretching at a draw ratio of 1.1 times in the transverse direction. Then, by conveying between rolls of the heat treatment apparatus, it was further dried to produce an optical film having a thickness of 40 µm, which was used as a long substrate. The core layer of the long substrate was 36 μm thick, and the outer layers disposed on both sides of the core layer were 2 μm thick, respectively. The in-plane retardation of the obtained cellulose acylate film 1 was 0 nm.

〔Preparation of a long liquid crystal film〕

A photo-alignment layer and a liquid crystal layer were formed as follows while conveying the produced cellulose acylate film 1 in the longitudinal direction using a roll-to-roll manufacturing apparatus as shown in FIG. 3 to produce a long liquid crystal film. .

The following composition 1 for a photo-alignment film was continuously applied to the surface of one side of the produced cellulose acylate film 1 with a bar coater. After coating, the mixture was dried for 1 minute in a heating zone at 120 ° C, and the solvent was removed to form a layer of light isomerization composition (material layer) having a thickness of 0.3 µm. Subsequently, while being wound on a mirror-treated backing roll, a photo-alignment layer was formed by irradiating polarized ultraviolet rays (10 mJ / cm ² , using an ultra-high pressure mercury lamp) so that the polarization axis was formed at an angle of 45 degrees in the longitudinal direction. At this time, the mirror-treated backing roll was previously irradiated with green light from various angles and directions, and a surface having no scattering spots, scratches, grooves, or foreign matter was confirmed as a poet.

The surface roughness (maximum height roughness Rz) of the mirror-treated backing roll was measured by a method in accordance with JIS B0601 (2001) using a surface roughness meter (trade name SJ-310, manufactured by Mitsutoyo Co., Ltd.), and was 0.4 μm. .

Moreover, it was 1% when the ultraviolet reflectance (reflectance of wavelength 365nm) was measured using the spectrophotometer (MV-3100, Nippon Bunko Co., Ltd. product).

-------------------------------------------------- ---

Composition for optical alignment film 1

-------------------------------------------------- ---

Photoalignment polymer A described above 10 parts by mass

Nom coat TAB (manufactured by Nisshin Oilio Co., Ltd.) 1.52 parts by mass

Polyfunctional epoxy compound (Epolyd GT401, manufactured by Daicel)

12.2 parts by mass

Thermal acid generator (San-Aid SI-60, Sanshin Chemical Industry Co., Ltd.)

0.55 parts by mass

Butyl acetate 300 parts by mass

-------------------------------------------------- ---

Nom Court TAB

[Formula 2]

Subsequently, the composition 1 for optical anisotropic layer formation described below was applied with a bar coater on the long-formed photo-alignment layer to form a composition layer. The formed composition layer was once heated to 110 ° C in a heating zone, and then cooled to 75 ° C to stabilize the orientation.

Then, it was maintained at 75 ° C, and the orientation was fixed by ultraviolet irradiation (500 mJ / cm ² , using an ultra-high pressure mercury lamp) under a nitrogen atmosphere (oxygen concentration of 100 ppm) to form a liquid crystal layer having a thickness of 2.3 μm, which was wound up. The shaft was wound up to produce a long liquid crystal film. The average in-plane retardation Re (550) of the obtained liquid crystal film satisfies Re (450) / Re (550) <1.0 and 1.0 <Re (650) / Re (550) at 140nm, and the average slow axis direction is the longitudinal direction It was about 45 degrees.

-------------------------------------------------- ---

Coating solution for optically anisotropic layer (liquid crystal composition)

-------------------------------------------------- ---

The following liquid crystalline compound L-3 42.00 parts by mass

The following liquid crystalline compound L-4 42.00 parts by mass

The following polymerizable compound A-1 16.00 parts by mass

The following polymerization initiator S-1 (oxime type) 0.50 parts by mass

Leveling agent (compound G-1 below) 0.20 parts by mass

High-solve MTEM (manufactured by Toho Kagaku High School) 2.00 parts by mass

NK ester A-200 (manufactured by Shin-Nakamura Kagaku High School) 1.00 parts by mass

· Methyl ethyl ketone 424.8 parts by mass

-------------------------------------------------- ---

In addition, the group adjacent to the acryloyloxy group of the following liquid crystal compounds L-3 and L-4 represents a propylene group (a group in which a methyl group is substituted with an ethylene group), and the following liquid crystal compounds L-3 and L-4 are: Represents a mixture of positional isomers with different methyl group positions.

Liquid crystal compound L-3

[Formula 3]

Liquid crystal compound L-4

[Formula 4]

Polymerizable compound A-1

[Formula 5]

Polymerization initiator S-1

[Formula 6]

Compound G-1

[Formula 7]

(Measurement of surface axis direction, in-plane retardation, and area ratio of stripe-shaped areas)

The obtained long liquid crystal film is unwound, and a stripe-shaped light leakage region on an arbitrary 1 m long web is detected and marked by an automatic surface inspection machine according to the method of the rotational spectroscopic method, and then the liquid crystal film is included to include a marking site. The pieces were cut out, and the slow axis value and the retardation value in the slow axis direction were measured by KOBRA 21ADH (manufactured by Oji Keisoku Kiki Co., Ltd.) at 20 points at 0.5 mm intervals on a straight line crossing the stripe-shaped region. This was performed for 10 points of the same long liquid crystal film. As a result, the slow axis variation Δβ in the stripe-shaped region was less than 0.4 ° at any point, and the phase difference values in the slow axis direction were all 140 nm. The surface and cross section of each stripe-shaped region were observed with an optical microscope, but no foreign matter or film thickness fluctuation was observed in any of them.

Moreover, when the area ratio of the stripe-shaped region was measured by the method described above, it was 2%.

[Examples 2 to 4, Comparative Examples 1 and 2]

A long liquid crystal film was produced in the same manner as in Example 1 except that the maximum height roughness Rz of the backup roll and the ultraviolet reflectance were respectively changed as shown in Table 1 below, and the slow axis direction and the in-plane phase difference were measured.

Table 1 shows the area ratios of the slow axis fluctuation Δβ and the stripe-shaped region in each of the Examples and Comparative Examples.

(Evaluation in mounting on organic EL display device)

In the long liquid crystal films of each of the Examples and Comparative Examples obtained, a long linear polarizer (absorption axis is in the longitudinal direction) by a roll-to-roll process in a form in which the liquid crystal film has the substrate side as the polarizing plate side and the substrate also serves as a polarizing plate protective film. After bonding, it was once wound up and further cut to obtain a circular polarizing plate. On the liquid crystal film side of the obtained circularly polarizing plate, the positive C plate described in Example 0124 Paragraphs -0127 Paragraphs of Japanese Patent Application Publication No. 2015-200861 (however, the thickness of the positive C plate is controlled so that Rth at 550 nm is -65 nm) And transferring them) to obtain a laminate.

Next, the GALAXY SII manufactured by SAMSUNG, equipped with an organic EL panel, is disassembled, the original polarizing plate is peeled off, and the laminated body piece cut out to include the marking portion in the liquid crystal film from the laminate produced above is on the positive C plate side. The organic EL display device was produced by bonding together through a pressure-sensitive adhesive. The obtained organic EL display device was observed under natural light in a black display state, and it was visually evaluated whether an abnormality was observed.

Table 1 shows the results.

[Table 1]

1 Long description
2 Optical alignment layer
3 liquid crystal layer
10 long liquid crystal film
20 polarizer
21 straight polarizer
22, 53 adhesive layer
30 long liquid crystal film production equipment
31, 39, 42-46 rolls
32, 35 die
33, 36 heating devices
34, 37 light source
38 backup rolls
40 Long polarizing plate manufacturing equipment
41 release film
47, 48, 60 axis of rotation
49, 55, 61 winding shaft
50 image display device
51 Image display panel
52 Anti-reflection film

Claims (16)

A long liquid crystal film having a long substrate, a long optical alignment layer, and a long liquid crystal layer having an in-plane retardation in this order,
In the long liquid crystal layer, when the long liquid crystal film is sandwiched by a linear polarizer and a spectrometer and placed at a quenching position to irradiate light, a stripe-shaped region where light leakage occurs exists, and in the stripe-shaped region A long liquid crystal film, characterized in that the slow axis variation Δβ is greater than 0 ° and less than 0.04 °. The method according to claim 1,
The long liquid crystal film, wherein the in-plane retardation of the long liquid crystal layer is in the range of 100 nm to 250 nm. The method according to claim 1 or claim 2,
The in-plane retardation of the long liquid crystal film is in the range of 100nm to 250nm, the long liquid crystal film. The method according to any one of claims 1 to 3,
A long liquid crystal film in which the long base material satisfies the following formula.
｜ Re (550) ｜ ≤10nm
｜ Rth (550) ｜ ≤20nm The method according to any one of claims 1 to 4,
The in-plane retardation of the elongated liquid crystal layer is in the range of 110 nm to 160 nm, and the slow axis forms 45 degrees with respect to the longitudinal direction of the elongate substrate. The method according to any one of claims 1 to 5,
The in-plane retardation of the long liquid crystal film is in the range of 110 nm to 160 nm, and the slow axis of the long liquid crystal film forms 45 degrees with respect to the longitudinal direction of the long substrate. The method according to any one of claims 1 to 6,
The long liquid crystal film, wherein the long liquid crystal layer satisfies the following formula.
Re (450) / Re (550) <1.0
1.0 <Re (650) / Re (550) The method according to any one of claims 1 to 7,
The long liquid crystal film, wherein the long liquid crystal film satisfies the following formula.
Re (450) / Re (550) <1.0
1.0 <Re (650) / Re (550) The method according to any one of claims 1 to 8,
The ratio of the total area of the stripe-shaped region to the area of the surface of the elongated liquid crystal layer is 6% or less. The long polarizing plate which laminated | stacked the elongate liquid crystal film in any one of Claims 1-9, and a long linear polarizing plate in the longitudinal direction of each other. The method according to claim 10,
The long polarizing plate, wherein the absorption axis of the long linear polarizing plate forms 0 degrees or 90 degrees with respect to the longitudinal direction of the long linear polarizing plate, and the crossing angle with the slow axis of the long liquid crystal film forms 45 degrees. The method according to claim 11,
The in-plane retardation of the long liquid crystal film is in the range of 110nm to 160nm, a long polarizing plate. An image display device comprising a sheet-shaped polarizing plate cut out from the long polarizing plate according to any one of claims 10 to 12. The method according to any one of claims 1 to 9,
The liquid crystal layer is provided between the photo-alignment layer and the liquid crystal layer, or between the long substrate and the photo-alignment layer, at least one of the long liquid crystal film is provided to be peelable. A method for producing a long liquid crystal film according to any one of claims 1 to 9 and 14,
It has a photo-alignment process of irradiating ultraviolet rays to the material layer to be a photo-alignment layer formed on the elongate substrate, while conveying the elongate substrate in the longitudinal direction,
In the photo-alignment process, when irradiating ultraviolet rays to the material layer, a surface opposite to the surface on which the material layer is formed on the elongate substrate is supported by a backup roll,
The maximum height roughness Rz of the surface of the said backup roll is 0.7 micrometers or less, The manufacturing method of a long liquid crystal film. The method according to claim 15,
The reflectance of the surface of the said backup roll with respect to ultraviolet rays is 10% or less, The manufacturing method of a long liquid crystal film.

Images