JP7491349B2 - Long retardation film, method for producing long retardation film, and method for producing long optical film - Google Patents

Description

The present invention relates to a long retardation film, a long optical film, a long polarizing film, a method for manufacturing a long retardation film, and a method for manufacturing a long optical film.

Retardation films and polarizing films are applied to display devices such as organic EL displays and liquid crystal displays. As disclosed in Patent Document 1, a retardation film can be produced by applying a polymerizable liquid crystal composition onto a substrate to form a coating film on the substrate, and curing the coating film. A long retardation film can be produced by forming a long coating film on a long substrate and curing the coating film. A long polarizing film can be produced using a long retardation film. The roll-to-roll production method is excellent in terms of production efficiency and production costs.

JP 2021-184046 A

In Patent Document 1, a long polarizing film is manufactured by transferring the retardation layer of a long retardation film to a long transfer film. In the long polarizing film manufactured in this manner, burrs may occur at the width direction ends of the transferred retardation layer. When burrs occur, foreign matter gets mixed into the long polarizing film, and the manufacturing line is contaminated by the foreign matter. The present disclosure aims to suppress the occurrence of burrs at the ends of the retardation layer.

The long retardation film according to one embodiment of the present disclosure is
A long retardation film including a longitudinal direction and a transverse direction,
A substrate;
A retardation layer overlapped with the base material,
The retardation layer includes a first region, a pair of second regions, and a pair of third regions,
The first region is located between the pair of second regions in the short side direction,
the pair of second regions are located between the pair of third regions in the short-side direction,
The retardation layer includes a cured product of a liquid crystal composition,
The second region is non-oriented,
The third region is horizontally aligned.

The long optical film according to one embodiment of the present disclosure comprises:
A long optical film including a longitudinal direction and a transverse direction,
A substrate, a bonding layer, and a retardation layer are provided in this order.
The retardation layer includes a first region and a pair of second regions,
The first region is located between the pair of second regions in the short side direction,
The retardation layer includes a cured product of a liquid crystal composition,
The second region is non-oriented.

In one embodiment of the present disclosure, the long polarizing film is
A long polarizing film including a longitudinal direction and a transverse direction,
a polarizing layer including a polarizer;
A retardation layer overlapping the polarizing layer,
The retardation layer includes a first region and a pair of second regions,
The first region is located between the pair of second regions in the short side direction,
The retardation layer includes a cured product of a liquid crystal composition,
The second region is non-oriented.

A method for producing a long retardation film according to an embodiment of the present disclosure includes:
A step of applying an alignment film-forming composition to a long substrate having a longitudinal direction and a lateral direction to form a first coating film;
a step of irradiating a central region of the first coating film, excluding end regions in the short side direction, with polarized light to form an alignment film from the first coating film, the central region of which has an alignment regulating force;
applying a liquid crystal composition to an intermediate including the substrate and the alignment film to form a second coating film;
and curing the second coating film to form a retardation layer including a cured product of the liquid crystal composition.
the retardation layer includes a first region facing the central region, a second region facing the end region, and a third region facing the base material on the outer side of the alignment film in the short-side direction,
The third region is horizontally aligned.

A method for producing a long optical film according to an embodiment of the present disclosure includes the steps of:
A step of laminating a long retardation film according to an embodiment of the present disclosure onto a long transfer film including a bonding layer;
and peeling off the base material from the long retardation film bonded to the bonding layer.

This disclosure makes it possible to prevent burrs from forming on the ends of the retardation layer.

FIG. 1 is a diagram for explaining one embodiment, and is a vertical sectional view showing an example of a long retardation film. FIG. 2 is a plan view showing an example of the long retardation film of FIG. FIG. 3 is a perspective view showing an example of a long retardation film, a transfer film, a long optical film, and a long polarizing film. FIG. 4 is an enlarged view of a portion of FIG. FIG. 5 is a diagram for explaining an example of a method for manufacturing the long retardation film of FIG. 6A to 6C are diagrams for explaining the manufacturing method of FIG. 7A to 7C are diagrams for explaining the manufacturing method of FIG. 8A to 8C are diagrams for explaining the manufacturing method of FIG. 9A to 9C are diagrams for explaining the manufacturing method of FIG. 10A to 10C are diagrams for explaining the manufacturing method of FIG. FIG. 11 is a vertical cross-sectional view showing an example of a long optical film and a long polarizing film produced using the long retardation film of FIG. FIG. 12 is a vertical cross-sectional view showing an example of a transfer film used in the production of the long optical film and the long polarizing film of FIG. FIG. 13 is a diagram illustrating an example of a method for producing the long optical film and the long polarizing film of FIG. 14A to 14C are diagrams for explaining the manufacturing method of FIG. 15A to 15C are diagrams for explaining the manufacturing method of FIG. 16A to 16C are diagrams for explaining the manufacturing method of FIG. FIG. 17 is a diagram showing an application example of an optical film and a polarizing film obtained from the long optical film and the long polarizing film of FIG. FIG. 18 is a diagram showing another application example of the optical film and the polarizing film. FIG. 19 is a cross-sectional view showing the long retardation film according to Example 1 together with a transfer film. FIG. 20 is a cross-sectional view showing the long retardation film according to Comparative Example 1 together with the transfer film. FIG. 21 is a cross-sectional view showing a long retardation film according to Comparative Example 2 together with a transfer film. FIG. 22 is a photograph showing the long optical film according to Example 1. FIG. 23 is a photograph showing a long optical film according to Comparative Example 1. As shown in FIG. FIG. 24 is a photograph showing a long optical film according to Comparative Example 2.

One embodiment of the present disclosure relates to the following [1] to [35].

[1] A long retardation film including a longitudinal direction and a transverse direction,
A substrate;
A retardation layer overlapped with the base material,
The retardation layer includes a first region, a pair of second regions, and a pair of third regions,
The first region is located between the pair of second regions in the short side direction,
the pair of second regions are located between the pair of third regions in the short-side direction,
The retardation layer includes a cured product of a liquid crystal composition,
The second region is non-oriented,
The third region is horizontally aligned.

[2] The third region has a third slow axis,
The long retardation film of [1], wherein a third orientation angle between the third slow axis and the longitudinal direction is 40° or more and 140° or less.

[3] The first region has a first slow axis,
The long retardation film according to [1] or [2], wherein a first orientation angle between the first slow axis and the longitudinal direction is 10° or more and 80° or less, or 100° or more and 170° or less.

[4] A long retardation film according to any one of [1] to [3], wherein the third region includes an end of the retardation layer in the short-side direction.

[5] A long retardation film according to any one of [1] to [4], wherein the first region includes the center of the retardation layer in the short-side direction.

[6] An alignment film is provided between the substrate, and the first region and the second region;
The long retardation film according to any one of [1] to [5], wherein the third region is in contact with the base material.

[7] The long retardation film of [6], wherein the alignment film includes a photoalignment film.

[8] The long retardation film according to claim 1, wherein the substrate includes a polyethylene film.

[9] The polyethylene film has a slow axis,
The long retardation film according to [8], wherein an angle between the slow axis and the longitudinal direction of the polyethylene film is 40° or more and 140° or less.

[10] A long retardation film according to any one of [1] to [9], wherein the length of the second region along the short side direction is 1 mm or more and 200 mm or less.

[11] A long retardation film according to any one of [1] to [10], wherein the length of the third region along the short side direction is 0.5 mm or more and 50 mm or less.

[12] A long retardation film according to any one of [1] to [11], in which the length of the first region along the short side direction is six times or more the length of the second region along the short side direction.

[13] An in-plane retardation Re(450) in the first region of the retardation layer at a wavelength of 450 nm is smaller than an in-plane retardation Re(550) in the first region of the retardation layer at a wavelength of 550 nm;
The in-plane retardation Re(550) is smaller than the in-plane retardation Re(650) in the first region of the retardation layer at a wavelength of 650 nm,
The long retardation film according to any one of [1] to [12], wherein the in-plane retardation Re(550) is 130 nm or more and 153 nm or less.

[14] A long optical film including a longitudinal direction and a transverse direction,
A substrate, a bonding layer, and a retardation layer are provided in this order.
The retardation layer includes a first region and a pair of second regions,
The first region is located between the pair of second regions in the short side direction,
The retardation layer includes a cured product of a liquid crystal composition,
The second region is non-oriented.

[15] A long polarizing film including a longitudinal direction and a lateral direction,
a polarizing layer including a polarizer;
A retardation layer overlapping the polarizing layer,
The retardation layer includes a first region and a pair of second regions,
The first region is located between the pair of second regions in the short side direction,
The retardation layer includes a cured product of a liquid crystal composition,
A long polarizing film, wherein the second region is non-oriented.

[16] The first region has a first slow axis,
The long polarizing film of [15], wherein a first orientation angle between the first slow axis and the longitudinal direction is 10° or more and 80° or less, or 100° or more and 170° or less.

[17] The long polarizing film of [15] or [16], wherein the second region includes an end of the retardation layer in the short-side direction.

[18] A long polarizing film according to any one of [15] to [17], wherein the first region includes the center of the retardation layer in the short-side direction.

[19] A long polarizing film according to any one of [15] to [18], wherein the length of the second region along the short side direction is 1 mm or more and 100 mm or less.

[20] A long polarizing film according to any one of [15] to [19], in which the length of the first region along the short side direction is 12 times or more the length of the second region along the short side direction.

[21] An in-plane retardation Re(450) in the first region of the retardation layer at a wavelength of 450 nm is smaller than an in-plane retardation Re(550) in the first region of the retardation layer at a wavelength of 550 nm,
The in-plane retardation Re(550) is smaller than the in-plane retardation Re(650) in the first region of the retardation layer at a wavelength of 650 nm,
The long polarizing film according to any one of [15] to [20], wherein the in-plane retardation Re(550) is 130 nm or more and 153 nm or less.

[22] A step of applying an alignment film-forming composition to a long substrate having a longitudinal direction and a transverse direction to form a first coating film;
a step of irradiating a central region of the first coating film, excluding end regions in the short side direction, with polarized light to form an alignment film from the first coating film, the central region of which has an alignment regulating force;
applying a liquid crystal composition to an intermediate including the substrate and the alignment film to form a second coating film;
and curing the second coating film to form a retardation layer including a cured product of the liquid crystal composition.
the retardation layer includes a first region facing the central region, a second region facing the end region, and a third region facing the base material on the outer side of the alignment film in the short-side direction,
The method for producing a long retardation film, wherein the third region is horizontally aligned.

[23] The third region has a third slow axis,
The method for producing a long retardation film according to [22], wherein a third orientation angle between the third slow axis and the longitudinal direction is 40° or more and 140° or less.

[24] The first region has a first slow axis,
The method for producing a long retardation film according to [22] or [23], wherein a first orientation angle between the first slow axis and the longitudinal direction is 10° or more and 80° or less, or 100° or more and 170° or less.

[25] The method for producing a long retardation film according to any one of [22] to [24], wherein the third region includes an end of the retardation layer in the short direction.

[26] The method for producing a long retardation film according to any one of [22] to [25], wherein the first region includes the center of the retardation layer in the short-side direction.

[27] The substrate includes a polyethylene film having a slow axis,
The method for producing a long retardation film according to any one of [22] to [26], wherein an angle between the slow axis and the longitudinal direction of the polyethylene film is 40° or more and 140° or less.

[28] The method for producing a long retardation film according to any one of [22] to [27], wherein the length of the second region along the short side direction is 1 mm or more and 200 mm or less.

[29] The method for producing a long retardation film according to any one of [22] to [28], wherein the length of the third region along the short side direction is 0.5 mm or more and 50 mm or less.

[30] A method for producing a long retardation film according to any one of [22] to [29], wherein the length of the first region along the short side direction is six times or more the length of the second region along the short side direction.

[31] An in-plane retardation Re(450) in the first region of the retardation layer at a wavelength of 450 nm is smaller than an in-plane retardation Re(550) in the first region of the retardation layer at a wavelength of 550 nm,
The in-plane retardation Re(550) is smaller than the in-plane retardation Re(650) in the first region of the retardation layer at a wavelength of 650 nm,
The method for producing a long retardation film according to any one of [22] to [30], wherein the in-plane retardation Re(550) is 130 nm or more and 153 nm or less.

[32] A step of laminating a long retardation film according to any one of [1] to [13] onto a long transfer film including a bonding layer;
and peeling off the base material from the long retardation film bonded to the bonding layer.

[33] The long optical film includes the first region and a part of the second region of the retardation layer,
The method for producing a long optical film according to [32], wherein the third region of the retardation layer and a remainder other than the part of the second region remain on the base material.

[34] The method for producing a long optical film according to [32] or [33], in which, when the long retardation film is laminated on the transfer film, the second region faces the end of the bonding layer in the short-side direction, and the third region is located outside the bonding layer in the short-side direction and faces the substrate of the transfer film.

[35] The method for producing a long optical film according to any one of [32] to [34], wherein the transfer film includes a polarizing layer that includes a polarizer.

The following describes in detail one embodiment of the present disclosure. In the drawings accompanying this specification, the scale and aspect ratios have been appropriately altered and exaggerated from those of the actual product for the sake of ease of illustration and understanding.

In this specification, terms such as "film," "sheet," and "plate" are not distinguished from one another solely on the basis of differences in name. For example, a "retardation film" cannot be distinguished solely from a component called a retardation sheet or retardation plate. A "polarizing film" cannot be distinguished solely from a component called a polarizing sheet or polarizing plate.

"Film surface (sheet surface, plate surface)" refers to a surface that coincides with the planar direction of the target film-like (sheet-like, plate-like) member when the target film-like (sheet-like, plate-like) member is viewed overall and from a global perspective. The normal direction to a film-like (sheet-like, plate-like) member refers to the normal direction to the film surface (sheet surface, plate surface) of the film-like (sheet-like, plate-like) member.

In this specification, when multiple upper limit candidates and multiple lower limit candidates are given for a certain parameter, the numerical range of the parameter may be constructed by combining any one of the upper limit candidates and any one of the lower limit candidates. As an example, consider the description: "Parameter B may be A1 or more, A2 or more, or A3 or more. Parameter B may be A4 or less, A5 or less, or A6 or less." In this example, the numerical range of parameter B may be A1 or more and A4 or less, A1 or more and A5 or less, A1 or more and A6 or less, A2 or more and A4 or less, A2 or more and A5 or less, A2 or more and A6 or less, A3 or more and A4 or less, A3 or more and A5 or less, or A3 or more and A6 or less.

To clarify the directional relationships between the drawings, some drawings show a common first direction D1, second direction D2, and third direction D3 with arrows that have the same symbols. The tip of the arrow is the first side of each direction. The side opposite the tip of the arrow is the second side of each direction. An arrow pointing into the paper in a direction perpendicular to the paper surface of the drawing is shown by a symbol with an x in a circle, as shown in Figure 1, for example. An arrow pointing out from the paper in a direction perpendicular to the paper surface of the drawing is shown by a symbol with a dot in a circle, as shown in Figure 2, for example.

Note that Figs. 1 and 12 are hatched to show cross sections. Hatching is omitted in the other figures. Also, Figs. 8 to 11, 14, 16, and 19 to 21 are hatched to show the alignment regulating force of the alignment film 30 and the alignment state of the retardation layer 40. The hatching in Figs. 8 to 11, 14, 16, and 19 to 21 does not show cross sections.

<<Long Retardation Film 10>>
1 to 3 show an example of the long retardation film 10 according to the present embodiment. As shown in FIG. 1 and FIG. 2, the long retardation film 10 has a longitudinal direction and a transverse direction. The transverse direction may be perpendicular to the long retardation direction. In the figures, the longitudinal direction of the long retardation film 10 is shown as the second direction D2. The transverse direction of the long retardation film 10 is shown as the first direction D1. The long retardation film 10 spreads in the first direction D1 and the second direction D2. The normal direction of the long retardation film 10 is shown as the third direction D3. The third direction D3 is the thickness direction of the long retardation film 10. The first direction D1 and the second direction D2 may be perpendicular to each other. The third direction D3 may be perpendicular to the first direction D1. The third direction D3 may be perpendicular to the second direction D2.

As shown in FIG. 3, the long retardation film 10 can be handled as a roll 10R wound around a winding core 12 with the winding axis RA as the center. This improves the ease of handling of the long retardation film 10. As described below, the long retardation film 10 can be manufactured by a roll-to-roll manufacturing method. The long retardation film 10 is excellent in terms of production efficiency and manufacturing costs.

The long retardation film 10 according to the present embodiment includes a substrate 20 and a retardation layer 40 laminated on the substrate 20, as shown in FIG. 4. The substrate 20 is long. The retardation layer 40 is long. The retardation layer 40 includes a first region 41, a pair of second regions 42, and a pair of third regions 43. The first region 41 is located between the pair of second regions 42 in the short direction. The pair of second regions 42 are located between the pair of third regions 43 in the short direction. The retardation layer 40 includes a cured product of a liquid crystal composition. The second region 42 is non-oriented. The third region 43 has horizontal orientation.

"Long" means that the object, such as a film, has a length of 5 m or more when unfolded, and may have a length of 10 m or more, or may have a length of 100 m or more. "Longitudinal direction" means the direction along the longest edge when the object, such as a film, is unfolded. "Transverse direction" means the direction in which the object, such as a film, has the shortest length when unfolded.

As described below, the long retardation film 10 is laminated on a long transfer film 50 including a bonding layer 53, and then the substrate 20 is peeled off from the long retardation film 10 bonded to the bonding layer 53, thereby transferring the retardation layer 40P to the transfer film 50. At this time, the occurrence of burrs on the end E40P in the short direction of the retardation layer 40P transferred to the transfer film 50 can be suppressed.

In the illustrated example, the long retardation film 10 further includes an alignment film 30. The alignment film 30 is located between the substrate 20 and the retardation layer 40 in the third direction D3. The alignment film 30 is long. Each layer of the long retardation film 10 will be described below with reference to the drawings.

<Retardation Layer 40>
The retardation layer 40 includes a cured product of a liquid crystal composition. The liquid crystal composition includes a liquid crystal compound. The liquid crystal composition may be a liquid crystal composition that undergoes a polymerization reaction, i.e., a polymerizable liquid crystal composition. The liquid crystal composition may include a polymerizable liquid crystal compound. The retardation layer 40 may include a polymerizable liquid crystal compound. The retardation layer 40 can be obtained by forming a coating film by applying a liquid crystal composition, and then curing the liquid crystal composition. The orientation state of the liquid crystal compound in the coating film may be adjusted to horizontal orientation, vertical orientation, tilted orientation, twisted orientation, hybrid orientation, or the like. By adjusting the orientation of the liquid crystal compound in the coating film, the optical characteristics of each region in the retardation layer 40 can be controlled. The orientation of the liquid crystal compound in each region of the retardation layer 40 will be described later.

The polymerizable liquid crystal compound is not particularly limited. The polymerizable liquid crystal compound may be a polymerizable liquid crystal compound used to form a layer having birefringence. The polymerizable liquid crystal compound is appropriately selected depending on the retardation value, wavelength dispersion, orientation, solubility, etc. desired for the retardation layer 40.

The polymerizable liquid crystal compound is a liquid crystal compound having a polymerizable group. The polymerizable liquid crystal compound contains a polymerizable functional group in the molecule. The polymerizable functional group allows the liquid crystal compound to be polymerized and fixed, so that the alignment stability is excellent and the change in phase difference over time can be reduced. The polymerizable liquid crystal compound may be a monofunctional liquid crystal compound containing a single polymerizable functional group. The polymerizable liquid crystal compound may be a polyfunctional liquid crystal compound containing two or more polymerizable functional groups. By having two or more polymerizable functional groups, the three-dimensional alignment of the liquid crystal compound becomes more stable and the change in phase difference over time can be further reduced. The polymerizable liquid crystal compound may be a polyfunctional liquid crystal compound containing three polymerizable functional groups. The polymerizable liquid crystal compound may be a polyfunctional liquid crystal compound containing two polymerizable functional groups. The polymerizable functional group may be polymerized by ionizing radiation such as ultraviolet light or an electron beam. The polymerizable functional group may be polymerized by the action of heat. The polymerizable liquid crystal compound may be a low molecular liquid crystal compound. The polymerizable liquid crystal compound may be a high molecular liquid crystal compound.

The polymerizable functional group may be a radically polymerizable functional group. An example of the radically polymerizable functional group is a functional group having at least one ethylenically unsaturated double bond capable of addition polymerization. Specific examples of the polymerizable functional group include a vinyl group with or without a substituent, an acrylate group (a general term including an acryloyl group, a methacryloyl group, an acryloyloxy group, and a methacryloyloxy group), and the like.

The polymerizable functional group may be a cationic polymerizable functional group. Specific examples of the polymerizable functional group include alicyclic ether groups (epoxy groups, oxetanyl groups, etc.), cyclic acetal groups, cyclic lactone groups, cyclic imino ether groups, cyclic thioether groups, spiro orthoester groups, vinyloxy groups, etc.

The polymerizable liquid crystal composition may contain a single polymerizable liquid crystal compound. The polymerizable liquid crystal composition may contain two or more polymerizable liquid crystal compounds. By combining two or more polymerizable liquid crystal compounds, the retardation value, wavelength dispersion, alignment, solubility, phase transition temperature, etc. can be adjusted.

The polymerizable liquid crystal composition may contain one or more materials such as a polymerizable compound that does not have liquid crystallinity, a photopolymerization initiator, a sensitizer, a leveling agent, an antioxidant, and a light stabilizer.

The wavelength dispersion of the retardation layer 40 may be reverse dispersion. Reverse dispersion means that the in-plane retardation Re increases from the short wavelength side to the long wavelength side. By making the wavelength dispersion of the retardation layer 40 reverse dispersion, the fluctuation of the in-plane retardation Re according to the wavelength can be suppressed, and the color expression is excellent. Examples of polymerizable liquid crystal compounds exhibiting reverse dispersion include those represented by general formula (1) in JP2019-73712A and those represented by general formula (II) in International Publication No. WO2017/043438.

The retardation layer 40 having reverse dispersion may have the following optical characteristics with respect to the in-plane retardation in the first region 41.
Re(450)<Re(550)
Re(550)<Re(650)
Re(450) is the in-plane retardation in the first region 41 of the retardation layer 40 at a wavelength of 450 nm. Re(550) is the in-plane retardation in the first region 41 of the retardation layer 40 at a wavelength of 550 nm. Re(650) is the in-plane retardation in the first region 41 of the retardation layer 40 at a wavelength of 650 nm.

Re(450), Re(550), and Re(650) in the first region 41 of the retardation layer 40 are not particularly limited. In an example in which the first region 41 of the retardation layer 40 is a λ/4 retardation layer, Re(450), Re(550), and Re(650) may be 90 nm or more, 100 nm or more, or 110 nm or more. In an example in which the first region 41 of the retardation layer 40 is a λ/4 retardation layer, Re(450), Re(550), and Re(650) may be 180 nm or less, 160 nm or less, or 150 nm or less. In an example in which the first region 41 of the retardation layer 40 is a λ/4 retardation layer, the in-plane retardation Re(550) may be 130 nm or more, 133 nm or more, or 136 nm or more. In an example in which the first region 41 of the retardation layer 40 is a λ/4 retardation layer, the in-plane retardation Re(550) may be 153 nm or less, 150 nm or less, or 147 nm or less. By setting the in-plane retardation in the first region 41 of the retardation layer 40 in this manner, the first region 41 of the retardation layer 40 can be used as a circular polarizing plate in combination with a polarizer.

The thickness of the retardation layer 40 along the third direction D3 may be 0.1 μm or more, 0.5 μm or more, or 1.5 μm or more. The thickness of the retardation layer 40 may be 5.0 μm or less, 4.0 μm or less, or 3.0 μm or less. By setting the thickness of the retardation layer 40 in this manner, the above-mentioned in-plane retardation appropriate for a λ/4 retardation layer can be imparted to the first region 41 of the retardation layer 40.

The thicknesses of the components constituting the retardation layer 40 and the long retardation film 10, and the thicknesses of the components constituting the transfer film 50 and the long optical film 55 described below are the average values of measurements taken at 20 points in images of the long retardation film 10, the transfer film 50, etc., observed with a scanning transmission electron microscope (STEM).

The in-plane phase difference is the average of the measured values at 16 points. The 16 measurement points are the centers of measurement when lines are drawn that divide the area inside the margin into 5 equal parts vertically and horizontally, with a margin of 1 cm from the outer edge of the measurement sample. If the measurement sample is rectangular, the measurement is performed with the 16 intersections of the lines that divide the area inside the margin into 5 equal parts vertically and horizontally, with a margin of 1 cm from the outer edge of the rectangle, as the center, and the in-plane phase difference of the measurement sample is determined by calculating the average value. If the measurement sample is a shape other than a rectangle, such as a circle, ellipse, triangle, or pentagon, the square or rectangle with the largest area inscribed in these shapes is identified, and 16 measurements are performed on the square or rectangle using the above method. The in-plane phase difference is measured using a product name "RETS-100" manufactured by Otsuka Electronics Co., Ltd.

The in-plane retardation Re is measured using the RETS-100 according to the following procedures (A1) to (A4).
(A1) First, turn on the light source of the RETS-100 and leave it for 60 minutes or more to stabilize it. After that, select the rotating analyzer method and the θ mode. By selecting this θ mode, the stage becomes a tilting rotating stage.
(A2) Next, the following measurement conditions are input into the RETS-100.
(Measurement condition)
・Retardation measurement range: Rotating analyzer method ・Measurement spot diameter: φ5mm
Tilt angle range: 0°
Measurement wavelength range: 400 nm to 800 nm
The average refractive index of the layer to be measured (for example, N=1.617 for a PET film)
Thickness: Thickness measured separately by STEM (A3). Next, background data is obtained without placing a sample in the device. The device is a closed system, and this is performed every time the light source is turned on.
(A4) After that, the sample is placed on the stage inside the device and measured.

If the object to be measured for in-plane phase difference is not large enough due to being narrow or other reasons, a measurement sample of sufficient size is prepared under the same conditions as the object to be measured, and the in-plane phase difference measured for this measurement sample is used as the in-plane phase difference of the object to be measured.

<Substrate 20>
The substrate 20 supports the retardation layer 40. In the illustrated example, the substrate 20 also supports the alignment film 30. The substrate 20 may be transparent. The term "transparent" means that the total light transmittance in accordance with JIS K7361-1:1997 is 50% or more, and may be 70% or more, 80% or more, or 90% or more. When the long retardation film 10 is manufactured by the roll-to-roll method, the substrate 20 may have flexibility that allows it to be wound into a roll.

Resin may be used as the material of the substrate 20. A resin substrate 20 has flexibility and is suitable for a roll-to-roll manufacturing method. Examples of materials for the substrate 20 include polyethylene terephthalate, polyurethane, polyimide, polyamide, polycarbonate, polyethylene naphthalate, polymethyl methacrylate, polymethyl acrylate, etc.

Biaxially stretched polyethylene films have high transparency and excellent mechanical properties. Biaxially stretched polyethylene films may have birefringence. As described later, biaxially stretched polyethylene films having birefringence can exert an orientation control force on the liquid crystal compound contained in the liquid crystal composition for forming the retardation layer 40. In many resin substrates such as polyethylene films, the stretching axis is the slow axis. In many resin substrates such as biaxially stretched polyethylene films, the stretching direction with the largest stretching ratio is the slow axis. Resin films are usually stretched in the longitudinal direction and the transverse direction perpendicular to the longitudinal direction. The stretching ratio in the transverse direction is greater than the stretching ratio in the longitudinal direction. The orientation angle θ20 of the slow axis of the biaxially stretched resin substrate 20 with respect to the longitudinal direction may be 40° or more, 50° or more, 60° or more, 70° or more, or 80° or more. The orientation angle θ20 may be 140° or less, 130° or less, 120° or less, 110° or less, or 100° or less. The orientation angle θ20 may be 90°. As shown in FIG. 4, the orientation angle is the size of the angle between the slow axis and the longitudinal direction (second direction D2). The orientation angle is the size of the angle that the slow axis makes in the counterclockwise direction with respect to the reference axis AS, which is an axis extending on one side in the longitudinal direction. The orientation angle is specified as an angle equal to or greater than 0° and less than 180°. In the example shown in FIG. 4, the reference axis AS faces the first side in the second direction D2.

The substrate 20 may contain one or more of the following in the binder resin made of the above-mentioned materials: flame retardant, antiblocking agent, antioxidant, light stabilizer, tackifier, antistatic agent, etc.

The thickness of the substrate 20 along the third direction D3 may be 10 μm or more, 25 μm or more, or 30 μm or more. The thickness of the substrate 20 may be 1000 μm or less, 200 μm or less, or 150 μm or less.

The surface of the substrate 20 facing the alignment film 30 and the retardation layer 40 may not be surface-treated. When the retardation layer 40 is transferred to the transfer film 50 as described below, the substrate 20 having an untreated surface can be easily peeled off from the long retardation film 10. The surface of the substrate 20 not facing the alignment film 30 and the retardation layer 40 may be surface-treated.

<Alignment film 30>
1 and 2, the long retardation film 10 includes an alignment film 30 between a substrate 20 and a retardation layer 40. The alignment film 30 has an alignment regulating force. The alignment film 30 adjusts the alignment of the retardation layer 40. The alignment film 30 aligns the liquid crystal compound included in the retardation layer 40 in a certain direction.

The alignment film 30 exerts an alignment control force on the liquid crystal compound as described below. The alignment film may be a rubbed alignment film. The rubbed alignment film is imparted with an alignment control force by a rubbing treatment. The rubbed alignment film is obtained by applying an alignment film-forming composition onto the substrate 20 to form a coating film on the substrate 20, and then rubbing the coating film using a rubbing roll or the like. The alignment film 30 is more preferably a photo-alignment film. The photo-alignment film is imparted with an alignment control force by irradiating it with polarized light.

The material of the alignment film is not particularly limited according to the above. Materials used as materials for rubbing alignment films or materials for photoalignment films may be used as materials for the alignment film. Examples of materials for rubbing alignment films include polyvinyl alcohol resins, polyimide resins, polyamide resins, etc.

As the material for the photo-alignment film, a photo-alignment material that exhibits an alignment control force when irradiated with polarized light is more preferably used. The material for the photo-alignment film may be either a photodimerization type material or a photoisomerization type material. The photo-alignment film is obtained by applying the photo-alignment material onto the substrate 20 to form a coating film on the substrate 20, and then irradiating the coating film of the photo-alignment material with polarized light to harden the coating film.

The thickness of the alignment film 30 along the third direction D3 may be 1 nm or more, or 60 nm or more. The thickness of the alignment film 30 may be 1000 nm or less, or 500 nm or less.

<Optical Properties of Retardation Layer 40>
In the long retardation film 10 according to the present embodiment, the retardation layer 40 includes a first region 41, a pair of second regions 42, and a pair of third regions 43. The first region 41 is located between the pair of second regions 42 in the short side direction. The pair of second regions 42 are located between the pair of third regions 43 in the short side direction.

The first region 41 is cut out from the long retardation film 10 and used as the retardation film 10X (see FIG. 3). The first region 41 is given a desired retardation according to the application of the retardation film 10X. In the first region 41, the liquid crystal compound may be horizontally aligned. Horizontal alignment means that the liquid crystal compound is arranged along the sheet surface of the retardation layer 40. In the first region 41, the liquid crystal compound may be arranged to extend along one direction along the plane defined by the first direction D1 and the second direction D2. In this example, the first region 41 may have in-plane birefringence. The first region 41 may have a first slow axis A41 in the plane. The alignment of the liquid crystal compound in the first region 41 may be adjusted by the alignment restraining force applied to the alignment film 30.

The first orientation angle θ41 between the first slow axis A41 of the first region 41 and the longitudinal direction (second direction D2) may be, for example, 10° or more, 20° or more, or 30° or more. In this example, the first orientation angle θ41 may be 80° or less, 70° or less, or 60° or less.

As another example, the first orientation angle θ41 may be 100° or more, 110° or more, or 120° or more. In this other example, the first orientation angle θ41 may be 170° or less, 160° or less, or 150° or less.

In the example shown in FIG. 4, the first region 41 may be used as a λ/4 retardation layer. The first region 41 of the retardation layer 40 may be laminated with a polarizing layer having a transmission axis in either the first direction D1 or the second direction D2 to form a circular polarizing plate. In this example, the first orientation angle θ41 between the first slow axis A41 of the first region 41 and the longitudinal direction (second direction D2) may be 35° or more, 40° or more, or 42° or more. In this example, the first orientation angle θ41 may be 55° or less, 50° or less, or 48° or less. In this example, the first orientation angle θ41 may be 45°.

In another example in which the first region 41 is used as a λ/4 retardation layer, the first orientation angle θ41 may be 125° or more, 130° or more, or 132° or more. In this other example, the first orientation angle θ41 may be 145° or less, 140° or less, or 138° or less. In this other example, the first orientation angle θ41 may be 135°.

As already explained, the orientation angle is the size of the angle between the slow axis and the longitudinal direction (second direction D2). The orientation angle is the size of the angle that the slow axis makes in the counterclockwise direction with respect to the reference axis AS, which is an axis extending to one side in the longitudinal direction. The orientation angle is specified as an angle greater than or equal to 0° and less than 180°.

As shown in FIG. 4, in the second region 42, the orientation of the polymerizable liquid crystal compound contained in the cured product of the polymerizable liquid crystal composition is not regulated and is irregular. As an example, by forming the second region 42 on an alignment film 30 to which no alignment regulating force is applied, non-polarization of the second region 42 can be achieved. As another example, non-alignment of the second region 42 can be achieved by forming the second region 42 on an optically isotropic substrate, for example, by forming the second region 42 on a substrate that is not stretched.

As shown in FIG. 4, the third region 43 has a third slow axis A43. In the third region 43, the liquid crystal compound may be horizontally aligned. As described above, horizontal alignment means that the liquid crystal compound is arranged along the sheet surface of the retardation layer 40. In the third region 43, the liquid crystal compound may be arranged to extend along one direction along the plane defined by the first direction D1 and the second direction D2. In this example, the third region 43 may have in-plane birefringence. The third region 43 may have a third slow axis A43 in the plane. The third orientation angle θ43 between the third slow axis A43 and the longitudinal direction (second direction D2) may be 40° or more, 50° or more, 60° or more, 70° or more, or 80° or more. The third orientation angle θ43 may be 140° or less, 130° or less, 120° or less, 110° or less, or 100° or less. The third orientation angle θ43 may be 90°.

The orientation of the liquid crystal compound in the third region 43 may be adjusted by the orientation restricting force imparted to the alignment film 30. The orientation of the liquid crystal compound in the third region 43 may be adjusted due to the orientation restricting force of the substrate 20 that has been given a slow axis by stretching.

The retardation layer of the long retardation film can be transferred to a long transfer film and used. In the retardation layer of a conventional long retardation film, the liquid crystal compound was oriented in a fixed direction over the entire surface. When the retardation layer of a conventional long retardation film was transferred to a transfer film and the substrate was peeled off from the long retardation film in the longitudinal direction, burrs could be generated at the end of the retardation layer in the short direction (width direction). A retardation film with burrs attached thereto and a product such as an optical film manufactured using the retardation film cannot be used as a product. In addition, the generated burrs contaminate the manufacturing line in which the long retardation film is handled. If the manufacturing line is contaminated with burrs, burrs may also be attached to products manufactured on the manufacturing line thereafter. In other words, the yield of products related to the long retardation film can be significantly reduced.

The inventors of the present disclosure have investigated the occurrence of burrs and found that the occurrence of burrs is affected by the relationship between the direction in which the substrate is peeled off from the long retardation film and the slow axis of the liquid crystal compound in the retardation layer.

First, as shown in FIG. 16, which will be referred to later, when the retardation layer is transferred to the transfer film, both end portions of the retardation layer are torn from the other portions and remain on the substrate. In other words, only the center portion of the retardation layer is transferred to the transfer film. It was confirmed that when the retardation layer is torn, it is likely to be torn along its slow axis. The orientation angle of the slow axis in a long retardation film is usually other than 0°, and is often 10° to 80° or 100° to 170°, for example, 45° or 135°. Retardation layers with an orientation angle of 45° or 135° were prone to burrs.

From this phenomenon, it is expected that by reducing the orientation angle, the retardation layer can be stably torn along the longitudinal direction (second direction D2), which is the peeling direction of the substrate. However, the orientation angle of the long retardation film is determined according to the application of the retardation film obtained from this long retardation film. It is possible to impart an orientation different from that of other regions only to the region where the retardation layer is to be torn, but this would complicate the manufacturing process.

Based on such considerations, in this embodiment, the orientation of the liquid crystal compound in each of the regions 41, 42, and 43 of the retardation layer 40 is adjusted. In this embodiment, the second region 42 and the third region 43 are not intended to be cut out from the long retardation film 10 and used as the retardation film 10X. The second region 42 is a region intended to be torn in the retardation layer 40 when the substrate 20 is peeled off from the long retardation film 10. The third region 43 is a region intended to remain on the substrate 20 peeled off from the long retardation film 10.

First, in this embodiment, the retardation layer 40 is non-oriented in the second region 42. That is, there is no regularity in the arrangement of the liquid crystal compounds. Therefore, in the second region 42, there is no direction in which the retardation layer 40 is likely to be torn. This allows the retardation layer 40 to be torn linearly in the second region 42 along the longitudinal direction (second direction D2), which is the peeling direction of the substrate 20.

However, it was confirmed that the adhesion of the retardation layer was reduced in the non-oriented region. When the non-oriented region with reduced adhesion spread to the end of the retardation layer in the first direction D1, the retardation layer could not be torn stably. Specifically, when attempting to tear the retardation layer, the retardation layer could not be torn linearly at the intended position. In addition, instead of tearing the retardation layer, the retardation layer could peel off from the substrate over the entire area in the first direction D1. For example, when the retardation layer is transferred away from the substrate up to the end area in the first direction D1, burrs due to cracks in the end area may occur, as in the comparative example described later, and the production line may be contaminated. When these phenomena occur, the product cannot be used as a product even if burrs due to poor tearing of the retardation layer do not occur.

On the other hand, in this embodiment, the liquid crystal compound in the third region 43 of the retardation layer 40 is horizontally aligned. The third region 43 in which the liquid crystal compound is horizontally aligned has stronger adhesion to the substrate 20 than the non-aligned second region 42. Therefore, the adhesion of the third region 43 to adjacent layers is improved. This promotes tearing in the linear second region 42 along the peeling direction of the substrate 20 when the substrate 20 is peeled off from the long retardation film 10.

As a result, burrs that occur at the end E40P in the short direction (first direction D1) of the retardation layer 40P transferred to the transfer film 50 can be reduced.

From the viewpoint of reducing burrs occurring at the end E40P of the transferred retardation layer 40P, it is effective to set the range of the third orientation angle θ43. When the slow axis A40 of the retardation layer 40 forms a large angle with respect to the direction in which the retardation layer 40 is torn, the retardation layer 40 has strong adhesion against tearing. From this viewpoint, the third orientation angle θ43 may be 40° or more and 140° or less. Furthermore, the third orientation angle θ43 may be 50° or more, 60° or more, 70° or more, or 80° or more. The third orientation angle θ43 may be 130° or less, 120° or less, 110° or less, or 100°. The third orientation angle θ43 may be 90°.

The first orientation angle θ41 with respect to the first slow axis A41 of the first region 41 is subject to restrictions according to the application of the long retardation film 10. The third orientation angle θ43 can be determined for the purpose of reducing the occurrence of burrs. It is effective to make the third orientation angle θ43 closer to 90° than the first orientation angle θ41. This makes it possible to reduce burrs occurring at the end E40P in the short direction (first direction D1) of the retardation layer 40P transferred to the transfer film 50 when the first orientation angle θ41 is set to 10° or more and 80° or less, or 100° or more and 170° or less, or when the first orientation angle θ41 is set to 35° or more and 55° or less, or 125° or more and 145° or less.

2 and 4, in the illustrated long retardation film 10, the first region 41 of the retardation layer 40 includes the center position in the short direction (first direction D1) of the long retardation film 10. The first region 41 of the retardation layer 40 includes the center position in the short direction (first direction D1) of the retardation layer 40. In addition, the third region 43 includes the end E40 of the retardation layer 40 in the short direction (first direction D1). Therefore, the area of the first region 41 intended to be used as the retardation film 10X can be secured to be large. On the other hand, the area of the third region 43 intended to remain on the substrate 20 can be reduced. As a result, the yield when manufacturing products from the long retardation film 10 can be sufficiently high.

In the illustrated example, the first region 41 and the second region 42 are adjacent to each other in the first direction D1. The second region 42 and the third region 43 are adjacent to each other in the first direction D1. Therefore, the yield rate can be sufficiently high when manufacturing products from the long retardation film 10.

From the viewpoint of increasing the yield when manufacturing products from a long retardation film and from the viewpoint of realizing stable transfer of the retardation layer 40, the dimensions of each region 41, 42, 43 may be determined as follows. The length L42 (see FIG. 4) along the short side direction (first direction D1) of the second region 42 may be 1 mm or more, 5 mm or more, or 10 mm or more. The length L42 along the short side direction (first direction D1) of the second region 42 may be 200 mm or less, 100 mm or less, or 50 mm or less. The length L43 (see FIG. 4) along the short side direction (first direction D1) of the third region 43 may be 0.5 mm or more, 1 mm or more, or 1.5 mm or more. The length L43 along the short side direction (first direction D1) of the third region 43 may be 50 mm or less, 40 mm or less, or 30 mm or less. The length L41 (see FIG. 2) of the first region 41 along the short side (first direction D1) may be 6 times or more, 12 times or more, or 20 times or more than the length L42 (see FIG. 4) of the second region 42 along the short side (first direction D1). The length L41 (see FIG. 2) of the first region 41 along the short side (first direction D1) may be 250 times or less than the length L42 (see FIG. 4) of the second region 42 along the short side (first direction D1).

The illustrated long retardation film 10 includes an alignment film 30 located between the substrate 20 and the first region 41 and the second region 42 of the retardation layer 40. The first region 41 and the second region 42 are in contact with the alignment film 30. The alignment film 30 is not located between the third region 43 and the substrate 20 in the third direction D3. The third region 43 is in contact with the substrate 20. According to this example, the alignment of the liquid crystal compound in the first region 41 and the second region 42 can be adjusted by the alignment film 30. The alignment of the liquid crystal compound in the third region 43 can be adjusted by the substrate 20. For example, the alignment of the liquid crystal compound in the third region 43 can be controlled by the surface properties of the substrate 20, the substrate alignment angle θ20 with respect to the substrate slow axis A20 of the substrate 20, etc. That is, the alignment of the three regions 41, 42, and 43 of the retardation layer 40 can be controlled with a high degree of freedom.

In the illustrated example, the alignment film 30 includes a central region 31 and a pair of end regions 32. The central region 31 faces the first region 41 of the retardation layer 40 in the third direction D3. The central region 31 includes the center in the short-side direction (first direction D1) of the long retardation film 10. The central region 31 includes the center in the short-side direction (first direction D1) of the alignment film 30. The central region 31 has an alignment regulation force. In the first region 41 of the retardation layer 40, the liquid crystal compound is aligned so as to extend along one direction corresponding to the alignment regulation force of the central region 31. Each end region 32 faces the second region 42 of the retardation layer 40 in the third direction D3. The end region 32 includes an end E30 in the short-side direction (first direction D1). The end region 32 does not have an alignment regulation force. In the second region 42 of the retardation layer 40, the liquid crystal compound is dispersed without regularity.

In this example, the alignment film 30 may be a photo-alignment film. With a photo-alignment film, the alignment control force in each region of the alignment film 30 can be easily adjusted independently from other regions.

In this example, the substrate 20 may include a biaxially stretched polyethylene film. The substrate orientation angle θ20 with respect to the substrate slow axis A20 of the biaxially stretched polyethylene film is usually 40° or more and 140° or less. By forming the third region 43 of the retardation layer 40 on the biaxially stretched polyethylene film, the third orientation angle θ43 with respect to the third slow axis A43 of the third region 43 is 40° or more and 140° or less. In other words, the third region 43 with extremely excellent adhesion to the substrate 20 can be easily formed.

The width W20 (see Figures 1 and 2) along the short side direction (first direction D1) of the substrate 20 may be 1000 mm or more, 1150 mm or more, or 1200 mm or more. The width W20 along the short side direction (first direction D1) of the substrate 20 may be 2000 mm or less, 1800 mm or less, or 1600 mm or less. The width W30 (see Figures 1 and 2) along the short side direction (first direction D1) of the alignment film 30 may be 950 mm or more, 1100 mm or more, or 1150 mm or more. The width W30 along the short side direction (first direction D1) of the alignment film 30 may be 1950 mm or less, 1750 mm or less, or 1550 mm or less. The width W40 (see FIG. 1 and FIG. 2) along the short side direction (first direction D1) of the retardation layer 40 may be 970 mm or more, 1120 mm or more, or 1170 mm or more. The width W40 along the short side direction (first direction D1) of the retardation layer 40 may be 1970 mm or less, 1770 mm or less, or 1570 mm or less. The width W40 along the short side direction (first direction D1) of the retardation layer 40 may be larger than the width W30 along the short side direction (first direction D1) of the alignment film 30. The length along the longitudinal direction (second direction D2) of the long retardation film 10 may be 5 m or more, 10 m or more, or 100 m or more. The length of the long retardation film 10 along the longitudinal direction (second direction D2) may be 10,000 m or less, 8,000 m or less, or 6,000 m or less.

<Method of Manufacturing Long Retardation Film 10>
Next, a description will be given of an example of a method for manufacturing the long retardation film 10. In the following description, the long retardation film 10 shown in Figs. 1 to 4 is manufactured by a roll-to-roll manufacturing method.

Figure 5 shows an example of a manufacturing method for the long retardation film 10 and an example of a manufacturing apparatus 70 for the long retardation film 10. The manufacturing apparatus 70 includes a supply core 71 that winds up the long substrate 20, a recovery core 72 that recovers the manufactured long retardation film 10, and a transport roll 73 that guides the substrate 20 and the long retardation film 10 from the supply core 71 to the recovery core 72. The manufacturing apparatus 70 includes a first supply device 76, a first drying device 77, and a first curing device 78 as devices for forming the alignment film 30 on the substrate 20. The manufacturing apparatus 70 includes a second supply device 81, a second drying device 82, and a second curing device 83 as devices for forming the retardation layer 40.

First, the substrate 20 wound around the supply core 71 is supplied. The substrate 20 transported by the transport roll 73 passes a position facing the first supply device 76. The first supply device 76 applies an alignment film forming composition 34 containing a photoalignment material to one side of the substrate 20. As shown in FIG. 6, a first coating film 35 of the alignment film forming composition 34 is formed on one side of the substrate 20.

The substrate 20 transported by the transport roll 73 passes a position facing the first drying device 77. The first drying device 77 dries the first coating film 35 of the composition for forming an alignment film 34. As an example, the first drying device 77 supplies a high-temperature, dry gas to the first coating film 35 of the composition for forming an alignment film 34.

The substrate 20 transported by the transport roll 73 passes through a position facing the first curing device 78. The first curing device 78 has a configuration corresponding to the curing process of the first coating film 35 of the composition for forming an alignment film 34. As shown in FIG. 7, the first curing device 78 may include a first exposure device 78A and a mask 78B. In the illustrated example, the first exposure device 78A emits polarized light toward the first coating film 35 of the composition for forming an alignment film 34. The mask 78B includes a transmission region 78B1 and a light-shielding region 78B2. The polarized light emitted from the first exposure device 78A passes through the transmission region 78B1. The polarized light emitted from the first exposure device 78A is shielded by the light-shielding region 78B2.

As shown in FIG. 7, the first coating film 35 of the composition for forming an alignment film 34 is irradiated with polarized light in the area facing the transmission area 78B1. By exposure to polarized light, the first coating film 35 is given an alignment control force according to the polarization. The exposed area of the first coating film 35 becomes the central area 31 of the alignment film 30. The first coating film 35 of the composition for forming an alignment film 34 is not irradiated with polarized light in the area facing the light-shielding area 78B2. The unexposed area of the first coating film 35 becomes the edge area 32 of the alignment film 30. The edge area 32 does not have an alignment control force.

As a result of the above, an intermediate body 15 including the substrate 20 and the alignment film 30 is obtained as shown in FIG. 8. In the intermediate body 15, the alignment film 30 includes a central region 31 and end regions 32. The alignment film 30 has an alignment control force only in the central region 31.

In Fig. 8, Figs. 9 to 11, 14, 16, and 19 to 21 described below, hatching is applied according to the alignment regulating force of the alignment film 30 and the alignment state of the retardation layer 40. The hatching applied in Figs. 11 to 11, 14, 16, and 19 to 21 does not indicate a cross section. In Figs. 8 to 11, 14, 16, and 19 to 21, no patterns are applied in areas where the alignment regulating force of the alignment film 30 is not generated, or in areas where the liquid crystal compound in the retardation layer 40 does not have a regular alignment.

As shown in FIG. 5, the intermediate 15 is transported by the transport roll 73 and passes a position facing the second supply device 81. The second supply device 81 applies a liquid crystal composition 44 containing a liquid crystal compound onto one surface of the intermediate 15. As shown in FIG. 9, a second coating film 45 is formed on one surface of the substrate 20 and on the alignment film 30. The second coating film 45 is not cured, and the liquid crystal compound can change its alignment within the second coating film 45.

In the region of the second coating film 45 facing the central region 31 of the alignment film 30 in the third direction D3, the liquid crystal compound is aligned to extend in a certain direction by the alignment regulating force of the central region 31. The first region 41 of the retardation layer 40 is formed in the region of the second coating film 45 facing the central region 31 of the alignment film 30 in the third direction D3. In the manufacture of the long retardation film 10 shown in FIG. 4, the liquid crystal compound in the first region 41 is aligned so that the first orientation angle θ41 is 45°.

The end region 32 of the alignment film 30 does not have an alignment restriction force. In the region of the second coating film 45 facing the end region 32 of the alignment film 30 in the third direction D3, the alignment of the liquid crystal compound is not restricted by the alignment film 30. In the region facing the end region 32, the alignment of the liquid crystal compound does not have regularity. The second region 42 of the retardation layer 40 is formed in the region of the second coating film 45 facing the end region 32 of the alignment film 30 in the third direction D3. In the production of the long retardation film 10 shown in FIG. 4, the second region 42 is unoriented.

As shown in FIG. 9, the second coating film 45 extends to the outside of the alignment film 30 in the short-side direction (first direction D1). "Outside" in the short-side direction means the side opposite to the center in the short-side direction. "Inside" in the short-side direction means the center side in the short-side direction. The end region of the second coating film 45 in the short-side direction (first direction D1) faces the substrate 20 in the third direction D3. The end region of the second coating film 45 in the short-side direction (first direction D1) is located on the substrate 20. In the end region of the second coating film 45 in the short-side direction (first direction D1), the liquid crystal compound receives an alignment restriction force from the substrate 20. A resin substrate usually exerts an alignment restriction force in the direction with the highest stretch ratio. A stretched resin substrate usually exerts an alignment restriction force in a direction parallel to its slow axis. A stretched polyester substrate exerts an alignment restriction force in a direction parallel to its slow axis. A third region 43 of the retardation layer 40 is formed in a region of the second coating film 45 that contacts the substrate 20 in the third direction D3. In the manufacture of the long retardation film 10 shown in FIG. 4, the liquid crystal compound in the third region 43 can be oriented so that the third orientation angle θ43 is 40° or more and 140° or less.

The intermediate 15 transported by the transport roll 73 passes a position facing the second drying device 82. The second drying device 82 dries the second coating film 45 of the liquid crystal composition 44. As an example, the second drying device 82 supplies a high-temperature, dry gas to the second coating film 45 of the liquid crystal composition 44.

The intermediate 15 transported by the transport roll 73 passes through a position facing the second curing device 83. The second curing device 83 has a configuration corresponding to the curing process of the second coating film 45 of the liquid crystal composition 44. As shown in FIG. 10, the second curing device 83 may include an exposure device 83A. In the illustrated example, the exposure device 83A emits ionizing radiation toward the second coating film 45 of the liquid crystal composition 44. The second coating film 45 of the liquid crystal composition 44 is irradiated with ionizing radiation from the second curing device 83 and cured. During the curing process, the second coating film 45 is cured while the liquid crystal compound maintains its alignment. In the first region 41 and the third region 43 of the retardation layer 40, the liquid crystal compound is horizontally aligned. In the second region 42, the liquid crystal compound is irregularly aligned.

In this manner, the long retardation film 10 is manufactured. The manufactured long retardation film 10 includes a longitudinal direction and a transverse direction. The long retardation film 10 includes a substrate 20, an alignment film 30, and a retardation layer 40. Each of the substrate 20, the alignment film 30, and the retardation layer 40 includes a longitudinal direction parallel to the longitudinal direction of the long retardation film 10. Each of the substrate 20, the alignment film 30, and the retardation layer 40 includes a transverse direction parallel to the transverse direction of the long retardation film 10.

<<Long Optical Film 55 and Long Polarizing Film 60>>
A long optical film 55 is manufactured using the long retardation film 10 described above. The long optical film 55 includes a long transfer film 50 and a long retardation layer 40P transferred from the long retardation film 10. FIG. 11 is a cross-sectional view showing an example of the long optical film 55. The long optical film 55 shown in FIG. 11 is manufactured by transferring the retardation layer 40P of the long retardation film 10 shown in FIG. 1 to FIG. 10 to the transfer film 50 shown in FIG. 12.

The transfer film 50 shown in FIG. 12 includes a long polarizing layer 52. The polarizing layer 52 transmits polarized light components that vibrate in a specific direction and blocks polarized light components that vibrate in a direction perpendicular to the specific direction. The long optical film 55 shown in FIG. 11 functions as a circular polarizer by combining the polarizing layer 52 with the first region 41 of the retardation layer 40P that functions as a λ/4 retardation layer. That is, in this example, the long optical film 55 becomes a long polarizing film 60.

Strictly speaking, the long polarizing film 60 functions as a circular polarizing plate for light of a certain wavelength, and typically functions as an elliptical polarizing plate for light of other wavelengths. A polarizing plate that functions as a circular polarizing plate for light of any wavelength between 400 nm and 800 nm is called a circular polarizing plate.

The transfer film 50 and the long optical film 55 will be described in further detail with reference to the specific examples shown in Figures 12 and 11.

The transferred film 50 and the long optical film 55 are long and have a long side direction and a short side direction. Each layer that is a component of the transferred film 50 and the long optical film 55 is also long and has a long side direction and a short side direction. The long side direction of the transferred film 50 is parallel to the long side direction of the components of the transferred film 50. The short side direction of the transferred film 50 is parallel to the short side direction of the components of the transferred film 50. The long side direction of the long optical film 55 is parallel to the long side direction of the components of the long optical film 55. The short side direction of the long optical film 55 is parallel to the short side direction of the components of the long optical film 55.

The transfer film 50 includes a substrate 51 and a bonding layer 53. The transfer film 50 shown in FIG. 12 includes a substrate 51, a polarizing layer 52, and a bonding layer 53 in this order in the third direction D3. The substrate 51 of the transfer film 50 is not particularly limited. The substrate 51 of the transfer film 50 may be the same as the substrate 20 of the long retardation film 10 described above. From the viewpoint of being able to apply the roll-to-roll manufacturing method, the material of the substrate 51 may be a resin. Examples of the material of the substrate 51 include a polyester film, a polycarbonate film, a cycloolefin polymer film, a triacetyl cellulose film, and an acrylic film. The thickness of the substrate 51 along the third direction D3 can be set to the same range as the thickness of the substrate 20 of the long retardation film 10 along the third direction D3.

The bonding layer 53 is not particularly limited. The bonding layer 53 may include an adhesive or may include a bonding material. The material of the bonding layer 53 is not particularly limited. The material of the bonding layer 53 may be a PVA-based adhesive or an acrylic-based adhesive. The thickness of the bonding layer 53 along the third direction D3 may be 1 μm or more, 1.5 μm or more, or 2 μm or more. The thickness of the bonding layer 53 may be 200 μm or less, 160 μm or less, or 120 μm or less.

The polarizing layer 52 may include an absorptive polarizer. The absorptive polarizer has an absorption axis and a transmission axis. The absorptive polarizer transmits linearly polarized light components that vibrate in a direction parallel to the transmission axis and absorbs linearly polarized light components that vibrate in a direction parallel to the absorption axis. The polarizing layer 52 may include a reflective polarizer. The reflective polarizer has a reflection axis and a transmission axis. The reflective polarizer transmits linearly polarized light components that vibrate in a direction parallel to the transmission axis and reflects linearly polarized light components that vibrate in a direction parallel to the reflection axis.

The polarizer of the polarizing layer 52 may be a polyvinyl alcohol film, a polyvinyl formal film, a polyvinyl acetal film, or an ethylene-vinyl acetate copolymer saponified film dyed with iodine or the like and stretched. The polarizer of the polarizing layer 52 may be a coating type polarizer coated with a dichroic guest-host material. The polarizer of the polarizing layer 52 may be a multilayer thin film type polarizer. The thickness of the polarizing layer 52 along the third direction D3 may be 0.5 μm or more, 1 μm or more, or 2 μm or more. The thickness of the polarizing layer 52 may be 150 μm or less, 120 μm or less, or 80 μm or less.

The end E53 in the short direction (first direction D1) of the bonding layer 53 may face the second region 42 of the retardation layer 40 included in the long retardation film 10. This allows the retardation layer 40 to be torn in the second region 42 when the retardation layer 40 is transferred. The second region 42 is unoriented. When the retardation layer 40 is torn in the second region 42, the effect of the retardation layer on the tearing direction can be reduced.

Since the end E53 of the bonding layer 53 faces the second region 42, the width of each layer along the short side direction (first direction D1) may be set as follows. The width W53 (see FIG. 12) along the short side direction (first direction D1) of the bonding layer 53 may be smaller than the width W40 along the short side direction (first direction D1) of the retardation layer 40 included in the long retardation film 10. The width W53 (see FIG. 12) along the short side direction (first direction D1) of the bonding layer 53 may be smaller than the total length L42, L41, L42 along the short side direction (first direction D1) of the first region 41 and the pair of second regions 42 of the retardation layer 40 included in the long retardation film 10. The width W53 (see FIG. 12) of the bonding layer 53 along the short side direction (first direction D1) may be greater than the length L41 along the short side direction (first direction D1) of the first region 41 of the retardation layer 40 included in the long retardation film 10.

The width W53 along the short side direction (first direction D1) of the bonding layer 53 may be 940 mm or more, 1090 mm or more, or 1140 mm or more. The width W53 along the short side direction (first direction D1) of the bonding layer 53 may be 1940 mm or less, 1740 mm or less, or 1540 mm or less.

The width W51 (see FIG. 12) along the short side direction (first direction D1) of the substrate 51 may be greater than the width W53 along the short side direction (first direction D1) of the bonding layer 53. The width W51 along the short side direction (first direction D1) of the substrate 51 may be set to a range similar to the width W20 along the short side direction (first direction D1) of the substrate 20.

The width W52 along the short side direction (first direction D1) of the polarizing layer 52 may be equal to or greater than the width W53 along the short side direction (first direction D1) of the bonding layer 53. The width W52 along the short side direction (first direction D1) of the polarizing layer 52 may be equal to or less than the width W51 along the short side direction (first direction D1) of the substrate 51. By setting the width of the polarizing layer 52 in this manner, it is possible to suppress the variation in the thickness of the transferred film 50 in the region where the bonding layer 53 is provided. This allows the retardation layer 40P of the long retardation film 10 to be stably transferred to the transferred film 50.

The length of the transferred film 50 along its longitudinal direction (second direction D2) may be set to a range similar to the length of the long retardation film 10 along its longitudinal direction (second direction D2).

As shown in FIG. 11, the long optical film 55 includes a transfer film 50 and a retardation layer 40P. The retardation layer 40P is a part of the retardation layer 40 included in the long retardation film 10. The retardation layer 40P of the long optical film 55 includes the first region 41 of the retardation layer 40 included in the long retardation film 10 and a part (first portion) 42A of each of the pair of second regions 42. The retardation layer 40P of the long optical film 55 does not include the remaining part (second portion) 42B other than the part 42A of each of the pair of second regions 42 of the retardation layer 40 included in the long retardation film 10, and a pair of third regions 43. As shown in FIG. 16, which will be referred to later, the inner part in the short direction (first direction D1) of each second region 42 of the retardation layer 40 is transferred to the transfer film 50. The outer portions of each second region 42 of the retardation layer 40 in the short direction (first direction D1) remain on the substrate 20 together with the third region 43.

In the example shown in FIG. 11, the transfer film 50 includes a substrate 51, a polarizing layer 52, a bonding layer 53, a retardation layer 40P, and an alignment film 30P in this order in the third direction D3. The alignment film 30P is a part of the alignment film 30 included in the long retardation film 10. The alignment film 30P is a part of the alignment film 30 included in the long retardation film 10 that faces the retardation layer 40P in the third direction D3. The alignment film 30P of the transfer film 50 includes the central region 31 of the alignment film 30 included in the long retardation film 10 and a part (first part) 32A of each of a pair of end regions 32. The alignment film 30P of the transfer film 50 does not include the remaining part (second part) 32B other than the part 32A of each of the pair of end regions 32 of the alignment film 30 included in the long retardation film 10. The inner portion of each end region 32 of the alignment film 30 in the short direction (first direction D1) is transferred to the transfer film 50. The outer portion of each end region 32 of the alignment film 30 in the short direction (first direction D1) remains on the substrate 20.

The long optical film 55 shown in FIG. 12 functions as a long polarizing film 60. In this application, the retardation layer 40P functions as a λ/4 retardation layer. The angle between the first slow axis A41 in the first region 41 of this retardation layer 40P and the transmission axis of the polarizing layer 52 may be 35° or more, 40° or more, or 42° or more. The angle between the first slow axis A41 of the retardation layer 40P and the transmission axis of the polarizing layer 52 may be 55° or less, 50° or less, or 48° or less. The angle between the first slow axis A41 of the retardation layer 40P and the transmission axis of the polarizing layer 52 may be 45°.

An example of a method for manufacturing a long optical film 55 will be described. In the following description, a long polarizing film 60 shown in FIG. 11 is manufactured as an example of a long optical film 55 by a roll-to-roll manufacturing method.

FIG. 13 shows an example of a method for manufacturing a long optical film 55 and an example of a manufacturing apparatus 90 for the long optical film 55. The manufacturing apparatus 90 includes a first supply core 91, a second supply core 92, a first recovery core 93, a second recovery core 94, and a transport roll 95. The first supply core 91 unwinds the long retardation film 10. The long retardation film 10 may be manufactured in advance and wound around the first supply core 91. Instead of the illustrated example, the long retardation film 10 may be continuously manufactured and sent out to the transport roll 95. The second supply core 92 unwinds the long transfer film 50. The long transfer film 50 may be manufactured in advance and wound around the second supply core 92. Instead of the illustrated example, the long transfer film 50 may be continuously manufactured and sent out to the transport roll 95. The first recovery core 93 recovers the manufactured long optical film 55. The second recovery core 94 recovers the long substrate 20. The transport rolls 95 include a first transport roll 95A and a second transport roll 95B.

First, the long retardation film 10 is supplied from the first supply core 91 toward the first transport roll 95A. In parallel with the supply of the long retardation film 10, the transfer film 50 is supplied from the second supply core 92 toward the first transport roll 95A. As shown in FIG. 14, the long retardation film 10 and the transfer film 50 are supplied between a pair of first transport rolls 95A. Between the pair of first transport rolls 95A, the long retardation film 10 and the transfer film 50 are stacked. The retardation layer 40 of the long retardation film 10 and the bonding layer 53 of the transfer film 50 come into contact with each other. The pair of first transport rolls 95A push the long retardation film 10 and the transfer film 50 toward each other. As a result, the retardation layer 40 is bonded to the bonding layer 53.

As shown in FIG. 14, both ends E53 of the bonding layer 53 face the second region 42 of the retardation layer 40 in the third direction D3. That is, the bonding layer 53 bonds to the first region 41 of the retardation layer 40 and the part 42A, which is the inner part in the first direction D1 of the pair of second regions 42. The bonding layer 53 does not face the pair of third regions 43 of the retardation layer 40 and the remaining part 42B other than the part 42A, which is the outer part in the first direction D1 of the pair of second regions 42, in the third direction D3. When the long retardation film 10 is laminated on the transfer film 50, the third region 43 and the remaining part 42B of the second region 42 are located outside the bonding layer 53 in the short direction (first direction D1).

Next, as shown in FIG. 13, the stacked long retardation film 10 and the transfer film 50 are fed toward between the second transport rolls 95B. As shown in FIG. 13 and FIG. 15, after the long retardation film 10 passes between the pair of second transport rolls 95B, the substrate 20 is peeled off from the long retardation film 10. In the roll-to-roll manufacturing method, the substrate 20 is peeled off along the second direction D2, which is the longitudinal direction.

As shown in FIG. 16, the portion of the retardation layer 40 that was bonded to the bonding layer 53 is maintained bonded to the bonding layer 53 as the retardation layer 40P and is transferred to the transfer film 50. The portion of the alignment film 30 that faces the retardation layer 40P in the third direction D3 is also transferred to the transfer film 50 as the alignment film 30P. As shown in FIG. 16, the retardation layer 40 is torn at a position in the second region 42 that faces the end E53 of the bonding layer 53 in the third direction D3. Similarly, the alignment film 30 is torn at a position in the end region 32 that faces the end E53 of the bonding layer 53 in the third direction D3.

That is, the first region 41 of the retardation layer 40 and a portion 42A that is the inner portion of the second region 42 in the first direction D1 are transferred to the transfer film 50 as the retardation layer 40P. The third region 43 of the retardation layer 40 and the remaining portion 42B that is the outer portion of the second region 42 in the first direction D1 remain in close contact with the substrate 20. The central region 31 of the alignment film 30 and a portion 32A that is the inner portion of the end region 32 in the first direction D1 are transferred to the transfer film 50 as the alignment film 30P. The remaining portion 32B that is the outer portion of the end region 32 in the first direction D1 of the alignment film 30 remains bonded to the substrate 20.

In this manner, the retardation layer 40P and the alignment film 30P are transferred from the long retardation film 10 to the transfer film 50, thereby continuously producing a long polarizing film 60. The produced long polarizing film 60 is collected in a first collection core 93. The substrate 20 peeled off from the alignment film 30P and the retardation layer 40P is collected in a second collection core 94.

According to this embodiment, the second region 42 of the retardation layer 40, which is torn during transfer, is non-oriented. In the second region 42, the liquid crystal compounds are irregularly arranged. Therefore, the direction in which the retardation layer 40 is torn in the second region 42 is not easily affected by the orientation of the liquid crystal compounds contained in the retardation layer 40. In the second region 42, the retardation layer 40 can be torn generally along the longitudinal direction (second direction D2), which is the direction in which the substrate 20 is peeled off. In addition, in this embodiment, the liquid crystal compounds in the third region 43 of the retardation layer 40 are horizontally oriented. Therefore, when the retardation layer 40 is torn in the longitudinal direction (second direction D2), the third region 43 can stably maintain adhesion to the substrate 20. For these reasons, the retardation layer 40 is torn smoothly in the second region 42. As a result, it is possible to effectively suppress the occurrence of burrs at the end E40P in the short direction (first direction D1) of the retardation layer 40P.

In the illustrated example, the edge region 32 of the alignment film 30 is not provided with an alignment control force. In other words, the edge region 32 does not have a directional configuration. Therefore, the alignment film 30 is torn in the edge region 32 smoothly, generally along the peeling direction of the substrate 20. This also helps to prevent the occurrence of burrs.

In the above-mentioned specific example, the third region 43 has a third slow axis A43. The third orientation angle θ43 between the third slow axis A43 and the longitudinal direction may be 40° or more and 140° or less. According to such an example, the retardation layer 40 exhibits strong adhesion to adjacent layers in the third region 43. Therefore, the retardation layer 40 is stably torn in the second region 42, and the occurrence of burrs at the end E40P in the short direction (first direction D1) of the retardation layer 40P can be effectively suppressed.

From the viewpoint of reducing burrs occurring at the end E40P of the transferred retardation layer 40P, the third orientation angle θ43 may be 40° or more, 50° or more, 60° or more, 70° or more, or 80° or more. The third orientation angle θ43 may be 140° or less, 130° or less, 120° or less, 110° or less, or 100° or less. The third orientation angle θ43 may be 90°.

From the viewpoint of increasing the yield of the optical film 55X and the polarizing film 60X and from the viewpoint of realizing stable transfer of the retardation layer 40, the length L42A (see FIG. 11) along the short-side direction (first direction D1) of the second region (part) 42A included in the retardation layer 40P may be determined as follows. The length L42A may be 1 mm or more, 2 mm or more, or 5 mm or more. The length L42A may be 100 mm or less, 50 mm or less, or 25 mm or less. From the same viewpoint, the length L32A (see FIG. 11) along the short-side direction (first direction D1) of the end region 32 (i.e., part 32A) included in the alignment film 30P may be determined as follows. The length L32A may be 1 mm or more, 2 mm or more, or 5 mm or more. The length L32A may be 100 mm or less, 50 mm or less, or 25 mm or less. The length L41 along the short side direction (first direction D1) of the first region 41 included in the retardation layer 40P may be 12 times or more, 24 times or more, or 40 times or more than the length L42A along the short side direction (first direction D1) of the second region (part) 42A included in the retardation layer 40P. The length L41 may be 500 times or less than the length L42A.

The transfer film 50, the long optical film 55, and the long polarizing film 60 can be handled as the winding bodies 50R, 55R, and 60R wound around the winding core 12 with the winding axis RA as the center, as shown in FIG. 3, in the same manner as the long retardation film 10 described above. This makes it easier to handle the long films 50, 55, and 60. The long films 50, 55, and 60 can be manufactured by a roll-to-roll manufacturing method. The long films 50, 55, and 60 are excellent in production efficiency and manufacturing cost. By cutting the long optical film 55 and the long polarizing film 60 to the desired size, individual optical films 55X and individual polarizing films 60X can be obtained. According to this example, the optical film 55X and the polarizing film 60X having various dimensions can be obtained from the long optical film 55 and the long polarizing film 60 according to needs. Optical films 55X and polarizing films 60X with various dimensions can be provided at any time.

The optical film 55X and the polarizing film 60X obtained from the long optical film 55 and the long polarizing film 60 may be applied to the display device 100. In the example shown in FIG. 17, the optical film 55X and the polarizing film 60X are arranged to overlap the display element 101 serving as an image forming device. In this example, the optical film 55X and the polarizing film 60X have a reflection suppression function that suppresses reflection of external light such as ambient light on the surface of the display device 100. The reflection suppression function can improve the contrast of the image displayed by the display device 100.

Examples of the display element 101 include a liquid crystal display element, an organic EL display element, an inorganic EL display element, a plasma display element, an electronic paper display element, an LED display element (such as a micro LED), a quantum dot, and the like. These display elements may have a touch panel function inside the display element.

In the specific example shown in FIG. 18, the display device 100 constitutes an organic EL display device. The display device 100 includes an organic EL display panel 103 and an optical film 55X (polarizing film 60X). The optical film 55X (polarizing film 60X) is overlaid on the image display surface of the organic EL display panel 103 and exhibits a reflection suppression function. In this example, the optical film 55X includes a retardation layer 40P that functions as a λ/4 retardation layer and a polarizing layer 52 that functions as a polarizer. The retardation layer 40P is located between the polarizing layer 52 and the organic EL display panel 103.

The present disclosure will be described in more detail with reference to examples. The present disclosure is not limited to the following examples.

<Long Retardation Film>
As will be described below, the long retardation films according to Example 1, Comparative Example 1, and Comparative Example 2 were produced by a roll-to-roll process.

Example 1
By the manufacturing method described above with reference to FIGS. 5 to 10, the long retardation film shown in FIGS. 1 to 4 was manufactured by a roll-to-roll method.

The substrate used was a PET film "Cosmoshine A4160 (thickness 100 μm, PET film (A))" manufactured by Toyobo Co., Ltd. The substrate was a biaxially stretched film and had in-plane birefringence. The stretch ratio in the short direction in the biaxial stretching was greater than the stretch ratio in the long direction.

A first coating film having a thickness of 300 nm was formed by applying an alignment film-forming composition to the untreated surface (non-primer surface) of the substrate. The alignment film-forming composition contained a polycinnamate compound and a propylene glycol monomethyl ether solution (solid content 4.5%). The first coating film was dried by holding it in an atmosphere of 100°C for 1 minute. The first coating film was exposed to polarized light to prepare an alignment film. The polarized light exposure conditions were an irradiation wavelength of 310 nm and an irradiation dose of 20 mJ/ ^cm2 . As described above, an intermediate including a substrate and an alignment film was obtained.

As explained with reference to FIG. 7, the first coating film was partially exposed using a mask. Only the central region of the first coating film was exposed to polarized light. The edge regions of the first coating film were not exposed to polarized light. The central region of the resulting alignment film was imparted with an alignment control force that resulted in an alignment angle of 45°. The edge regions of the resulting alignment film were not imparted with an alignment control force.

A polymerizable liquid crystal compound was synthesized with reference to the synthesis of compound 4 in Example 4 of JP5962760B. This polymerizable liquid crystal compound exhibited reverse wavelength dispersion. A polymerizable liquid crystal composition was prepared by adding 4 parts by mass of Irgacure 907 as an initiator and 0.3 parts by mass of Megafac F-477 (manufactured by DIC Corporation) as a surfactant to 100 parts by mass of the polymerizable liquid crystal compound. The polymerizable liquid crystal composition further contained toluene so that the solid content was 20%. A second coating film was formed by coating the polymerizable liquid crystal composition on the surface of the intermediate on which the alignment film was formed.

Next, the second coating film was dried by being held in an atmosphere of 120° C. for 1 minute. Thereafter, the second coating film was irradiated with ultraviolet light at an irradiation dose of 300 mJ/cm ² using a Fusion-UV device manufactured by Heraeus, thereby curing the second coating film 45 and forming the retardation layer 40. In this manner, a long retardation film including the substrate, the alignment film, and the retardation layer was obtained.

As shown in FIG. 19, the retardation layer 40 included in the long retardation film 10 of Example 1 included a first region 41 facing the central region 31 of the alignment film 30 in the third direction D3, a pair of second regions 42 facing the end region 32 of the alignment film 30 in the third direction D3, and a pair of third regions 43 located on both sides of the alignment film 30 in the first direction D1 and facing the substrate 20 in the third direction D3. In the first region 41, the polymerizable liquid crystal compound was horizontally aligned at an orientation angle of 45°. In the second region 42, the polymerizable liquid crystal compound was non-oriented. In the third region 43, the polymerizable liquid crystal compound was horizontally aligned. The third orientation angle of the polymerizable liquid crystal compound in one of the pair of third regions 43 spaced apart in the first direction D1 was 60°. The third orientation angle of the polymerizable liquid crystal compound in the other third region 43 was 87°. The in-plane retardation Re in the first region was 140 nm. As mentioned above, the in-plane retardation Re was measured using the product name "RETS-100" manufactured by Otsuka Electronics Co., Ltd.

The width L41 of the first region 41 in the short direction (first direction D1) perpendicular to the longitudinal direction was 1250 mm. The width L42 of each second region 42 in the short direction (first direction D1) perpendicular to the longitudinal direction was 30 mm. The width L43 of each third region 43 in the short direction (first direction D1) perpendicular to the longitudinal direction was 5 mm.

(Comparative Example 1)
The manufacturing method of the long retardation film of Comparative Example 1 was different from the manufacturing method of the long retardation film of Example 1 only in that the entire region of the first coating film was exposed to polarized light. Therefore, in Comparative Example 1, the alignment film was given an alignment restriction force with an alignment angle of 45° in the entire region. In Comparative Example 1, the polymerizable liquid crystal compound was horizontally aligned at an alignment angle of 45° in the entire region of the retardation layer facing the alignment film.

20, the retardation layer 140 included in the long retardation film 110 of Comparative Example 1 included a first region 141 facing the alignment film 130 in the third direction D3, and a pair of third regions 143 located on both sides of the alignment film 130 in the first direction D1 and facing the substrate 120 in the third direction D3. In the first region 141, the polymerizable liquid crystal compound was horizontally aligned at an orientation angle of 45°. In the third region 143, the polymerizable liquid crystal compound was horizontally aligned. The third orientation angle of the polymerizable liquid crystal compound in one of the pair of third regions 143 spaced apart in the first direction D1 was 60°. The third orientation angle of the polymerizable liquid crystal compound in the other third region 143 was 87°. The in-plane retardation Re in the first region was 140 nm. As described above, the in-plane retardation Re was measured using a product name "RETS-100" manufactured by Otsuka Electronics Co., Ltd.

The width L141 in the short direction (first direction D1) perpendicular to the longitudinal direction of the first region 141 was 1310 mm. The width L143 in the short direction (first direction D1) perpendicular to the longitudinal direction of each third region 143 was 5 mm. The retardation layer of the long retardation film of Comparative Example 1 had a configuration in which the configuration of the first region 41 was applied to the region of the second region 42 of the retardation layer of the long retardation film of Example 1.

(Comparative Example 2)
In Comparative Example 2, an intermediate including a substrate and an alignment film was prepared in the same manner as in Example 1. The alignment film of the obtained intermediate included a central region having an alignment regulating force with an alignment angle of 45° and an end region having no alignment regulating force. However, in Comparative Example 2, the length of the end region of the alignment film in the first direction D1 was made longer than in Example 1. A retardation layer was prepared on the intermediate. The retardation layer was prepared by the same preparation method as in Example 1. However, in Comparative Example 2, the width of the retardation layer along the second direction was made shorter than the width of the alignment film along the second direction. The retardation layer was located only in the region facing the alignment film in the third direction D3.

As shown in FIG. 21, in the long retardation film 210 of Comparative Example 2, the retardation layer 240 included a first region 241 facing the central region 231 of the alignment film 230 in the third direction D3, and a second region 242 facing the end region 232 of the alignment film 230 in the third direction D3. In the first region 241, the polymerizable liquid crystal compound was horizontally aligned at an alignment angle of 45°. In the second region 242, the polymerizable liquid crystal compound was unaligned. The in-plane retardation Re in the first region was 140 nm. As described above, the in-plane retardation Re was measured using a product name "RETS-100" manufactured by Otsuka Electronics Co., Ltd.

The width L241 in the short direction (first direction D1) perpendicular to the longitudinal direction of the first region 241 was 1250 mm. The width L242 in the short direction (first direction D1) perpendicular to the longitudinal direction of each second region 242 was 30 mm. The retardation layer of the long retardation film according to Comparative Example 2 had a configuration in which the configuration of the second region 42 was applied to the region of the third region 43 of the retardation layer of the long retardation film according to Example 1.

<Evaluation>
13 to 16, the long retardation films of Example 1, Comparative Example 1, and Comparative Example 2 were laminated onto a long transfer film including a bonding layer, and then the substrate was peeled off from the long retardation film bonded to the bonding layer, to produce a long optical film by a roll-to-roll method. The length of the long retardation film and the transfer film along the second direction D2 was about 20 m, and a long optical film of about 20 m was produced.

(Transfer film)
As shown in FIGS. 19 to 21, the transfer film 50 included a substrate 51 and a bonding layer 53. The transfer film had the same configuration among Example 1, Comparative Example 1, and Comparative Example 2. Fujitac TD80UL (thickness 80 μm, TAC film (A)) manufactured by Fujifilm Corporation was used as the substrate of the transfer film. A bonding layer was laminated on this substrate to produce a long transfer film. The bonding layer was Panaclean PD-S1 (manufactured by Panac Corporation) (thickness 25 μm). The width W51 (see FIG. 12) along the short side direction (first direction D1) of the substrate in the transfer film was 1330 mm. The width W53 (see FIG. 12) along the short side direction (first direction D1) of the bonding layer in the transfer film was 1280 mm.

Example 1
As shown in FIG. 19, the long retardation film 10 of Example 1 was laminated with the transfer film 50. Both ends E53 in the first direction D1 of the bonding layer 53 of the transfer film 50 faced the second region 42 of the retardation layer 40 in the third direction D3. The substrate was peeled off from the long retardation film to transfer the retardation layer and the alignment film to the transfer film, thereby obtaining a long optical film. The retardation layer and the alignment film were torn at a position P1 in the second region in the first direction D1 and facing the end E53 of the bonding layer. The portions of the retardation layer and the alignment film that were outside the torn position P1 in the first direction D1 remained on the substrate.

(Comparative Example 1)
As shown in FIG. 20, the long retardation film 110 of Comparative Example 1 was laminated with the transfer film 50. Both ends E53 in the first direction D1 of the bonding layer 53 of the transfer film 50 faced the first region 141 of the retardation layer 140 in the third direction D3. By peeling the substrate from the long retardation film, the retardation layer and the alignment film were transferred to the transfer film to obtain a long optical film. The retardation layer and the alignment film were torn at a position P2 in the first region in the first direction D1, and the portion on the outside in the first direction D1 remained on the substrate.

(Comparative Example 2)
As shown in FIG. 21, the long retardation film 210 of Comparative Example 2 was laminated with the transfer film 50. Both ends E53 in the first direction D1 of the bonding layer 53 of the transfer film 50 faced the second region 242 of the retardation layer 240 in the third direction D3. By peeling the substrate from the long retardation film, the retardation layer and the alignment film were transferred to the transfer film to obtain a long optical film. In a part of the region along the longitudinal direction, the retardation layer and the alignment film were torn at a position P3 that was in the second region in the first direction D1, and the part that was outside the position P3 in the first direction D1 remained on the substrate. In the other wide region along the longitudinal direction, the retardation layer and the alignment film were transferred to the transfer film 50 over the entire width of the second region along the first direction D1 without being torn at the position P3 facing the end E53 of the bonding layer 53.

(Evaluation results)
The occurrence of burrs on the end of the retardation layer was confirmed for the long optical films produced as Example 1, Comparative Example 1, and Comparative Example 2. No burrs were generated for Example 1. Burrs were confirmed for Comparative Examples 1 and 2.

In Comparative Example 2, in a wide region along the longitudinal direction, the retardation layer and the alignment film were not torn at position P3, which is within the second region in the first direction D1, and one of the second regions in the first direction D1 of the retardation layer was transferred to the transferred film over its entire width, including its end. The alignment film was also transferred to the transferred film over its entire width, including its end, in a wide region along the longitudinal direction. As a result, in some regions in the longitudinal direction of the long optical film obtained as Comparative Example 2, there was a second region of the retardation layer that extended outward in the first direction D1 beyond the bonding layer. The second region that extended from the bonding layer was not bonded to the bonding layer. The second region that extended from the bonding layer remained on the long optical film as a burr or a foreign object broken from the retardation layer. During the manufacture of the long optical film of Comparative Example 2, the part of the retardation layer that was not bonded to the bonding layer came into contact with the first region of the retardation layer, and the first region was damaged to the extent that it could not be handled as a product in part. Such problems did not occur in Example 1 and Comparative Example 1.

Figure 22 is a photograph showing the end in the first direction D1 of the retardation layer of the long optical film obtained as Example 1. Figure 23 is a photograph showing the end in the first direction D1 of the retardation layer of the long optical film obtained as Comparative Example 1. Figure 24 is an optical microscope photograph showing the end in the first direction D1 of the retardation layer of the long optical film obtained as Comparative Example 2. The magnification of the photographs shown in Figures 22 to 24 is 2x. In the photographs shown in Figures 22 to 24, the retardation layer and alignment film have been transferred to the left-hand region.

10: Long retardation film, 10R: Roll, 10X: Retardation film, 12: Winding core, 15: Intermediate, 20: Substrate, 30: Alignment film, 30P: Alignment film, 31: Central region, 32: End region, 35: First coating film, 40: Retardation layer, 40P: Retardation layer, 41: First region, 42: Second region, 43: Third region, 44: Liquid crystal composition, 45: Second coating film, 50: Transferred film, 50R: Roll, 52: Polarizing layer, 53: Bonding layer, 55: Long optical film, 55R: Roll, 55X: Optical film, 60: Long polarizing film, 60R: Roll, 60X: Polarizing film, 70: Manufacturing device, 71: Supply core, 72: Recovery core, 73: Transport roll , 76: first supply device, 77: first drying device, 78: first curing device, 78A: first exposure device, 78B: mask, 81: second supply device, 82: second drying device, 83: second curing device, 90: manufacturing device, 91: first supply core, 92: second supply core, 93: first recovery core, 94: second recovery core, 95: transport roll, 95A: first transport roll, 95B: second transport roll, 100: display device, 103: organic EL display panel, D1: first direction, D2: second direction, D3: third direction, A20: substrate slow axis, A41: first slow axis, A42: second slow axis, A43: third slow axis, θ41: first orientation angle, θ42: second orientation angle, θ43: third orientation angle

Claims (26)

A long retardation film including a longitudinal direction and a transverse direction,
A substrate including a polyethylene terephthalate film;
A retardation layer overlapped with the base material,
The retardation layer includes a first region, a pair of second regions, and a pair of third regions,
The first region is located between the pair of second regions in the short side direction,
the pair of second regions are located between the pair of third regions in the short-side direction,
The retardation layer includes a cured product of a liquid crystal composition,
The second region is non-oriented,
The third region is in contact with the substrate, an orientation of a liquid crystal compound contained in the third region is controlled by a slow axis of the substrate, and the third region is horizontally aligned. the third region has a third slow axis,
The long retardation film according to claim 1 , wherein a third orientation angle between the third slow axis and the longitudinal direction is 40° or more and 140° or less. The first region has a first slow axis,
2 . The long retardation film according to claim 1 , wherein a first orientation angle between the first slow axis and the longitudinal direction is 10° to 80°, or 100° to 170°. The long retardation film according to claim 1, wherein the third region includes an end portion of the retardation layer in the short direction. The long retardation film according to claim 1, wherein the first region includes the center of the retardation layer in the short-side direction. The long retardation film according to claim 1 , further comprising an alignment film located between the substrate and the first and second regions. The long retardation film according to claim 6, wherein the alignment film includes a photoalignment film. The polyethylene terephthalate film has a slow axis,
2. The long retardation film according to claim 1, wherein an angle between the slow axis and the longitudinal direction of the polyethylene terephthalate film is 40° or more and 140° or less. The long retardation film according to claim 1, wherein the length of the second region along the short side direction is 1 mm or more and 200 mm or less. The long retardation film according to claim 1, wherein the length of the third region along the short side direction is 0.5 mm or more and 50 mm or less. The long retardation film according to claim 1, wherein the length of the first region along the short side direction is six times or more the length of the second region along the short side direction. An in-plane retardation Re(450) in the first region of the retardation layer at a wavelength of 450 nm is smaller than an in-plane retardation Re(550) in the first region of the retardation layer at a wavelength of 550 nm,
The in-plane retardation Re(550) is smaller than the in-plane retardation Re(650) in the first region of the retardation layer at a wavelength of 650 nm,
The long retardation film according to claim 1, wherein the in-plane retardation Re(550) is 130 nm or more and 153 nm or less. A step of applying an alignment film-forming composition to a long substrate having a longitudinal direction and a lateral direction to form a first coating film;
a step of irradiating a central region of the first coating film, excluding end regions in the short side direction, with polarized light to form an alignment film from the first coating film, the central region of which has an alignment regulating force;
applying a liquid crystal composition to an intermediate including the substrate and the alignment film to form a second coating film;
and curing the second coating film to form a retardation layer including a cured product of the liquid crystal composition.
The substrate comprises a polyethylene terephthalate film;
the retardation layer includes a first region facing the central region, a second region facing the end region, and a third region in contact with the base material on the outer side of the alignment film in the short-side direction,
The method for producing a long retardation film , wherein the alignment of the liquid crystal compound contained in the third region is controlled by a slow axis of the substrate, and the third region is horizontally aligned. the third region has a third slow axis,
The method for producing a long retardation film according to claim 13, wherein a third orientation angle between the third slow axis and the longitudinal direction is 40° or more and 140° or less. The first region has a first slow axis,
The method for producing a long retardation film according to claim 13, wherein a first orientation angle between the first slow axis and the longitudinal direction is 10° to 80°, or 100° to 170°. The method for producing a long retardation film according to claim 13, wherein the third region includes an end portion of the retardation layer in the short direction. The method for producing a long retardation film according to claim 13, wherein the first region includes a center of the retardation layer in the short-side direction. The substrate includes a polyethylene terephthalate film having a slow axis,
The method for producing a long retardation film according to claim 13, wherein an angle between the slow axis and the longitudinal direction of the polyethylene terephthalate film is 40° or more and 140° or less. The method for producing a long retardation film according to claim 13, wherein the length of the second region along the short side direction is 1 mm or more and 200 mm or less. The method for manufacturing a long retardation film according to claim 13, wherein the length of the third region along the short side direction is 0.5 mm or more and 50 mm or less. The method for manufacturing a long retardation film according to claim 13, wherein the length of the first region along the short side direction is six times or more the length of the second region along the short side direction. An in-plane retardation Re(450) in the first region of the retardation layer at a wavelength of 450 nm is smaller than an in-plane retardation Re(550) in the first region of the retardation layer at a wavelength of 550 nm,
The in-plane retardation Re(550) is smaller than the in-plane retardation Re(650) in the first region of the retardation layer at a wavelength of 650 nm,
The method for producing a long retardation film according to any one of claims 13 to 21, wherein the in-plane retardation Re(550) is 130 nm or more and 153 nm or less. A step of laminating the long retardation film according to any one of claims 1 to 12 onto a long transfer film including a bonding layer;
and peeling off the base material from the long retardation film bonded to the bonding layer. The long optical film includes the first region and a part of the second region of the retardation layer,
The method for producing a long optical film according to claim 23 , wherein the third region and a remainder other than the part of the second region of the retardation layer remain on the base material. The method for producing a long optical film according to claim 23, wherein, when the long retardation film is laminated on the transfer film, the second region faces an end of the bonding layer in the short-side direction, and the third region is located outside the bonding layer in the short-side direction and faces the substrate of the transfer film. The method for producing a long optical film according to claim 23, wherein the transfer film includes a polarizing layer including a polarizer.