Phase difference film, component of phase difference film, or method for manufacturing lens section or display system

Abstract

Provided are a method for manufacturing a phase difference film, a phase difference film assembly, or a lens section or a display system, whereby it is possible to satisfactorily reduce the weight of VR goggles while improving visibility. The invention discloses a manufacturing method of a display system, and the display system is used for displaying an image to a user. The manufacturing method comprises the following steps: forming a phase difference film which comprises more than two phase difference layers, wherein the absolute value of the sum of the phase difference change values RS of the phase difference layers is less than 3.0; the phase difference change value RS is an approximately linear slope of an in-plane phase difference Re (550) measured in a state in which the phase difference layer is applied with tension of 0 kg, 0.5 kg, 1 kg, 1.5 kg, and 2 kg), and is integrated with the lens section as a [lambda] / 4 member.

Description

Technical Field

[0001] This invention relates to a phase retardation film, a phase retardation film assembly, or a method for manufacturing a lens or display system. Existing technology

[0002] Image display devices, represented by liquid crystal displays and electroluminescent (EL) displays (such as organic EL displays), are rapidly becoming widespread. In order to realize image display and improve the performance of image display, optical components such as polarizing components and phase difference components are generally used in image display devices (see, for example, Patent Document 1).

[0003] In recent years, new applications for image display devices have been continuously developed. For example, goggles with displays for virtual reality (VR) have begun to be commercialized. Discussions are underway regarding the use of VR goggles in various situations, with hopes for improvements such as lighter weight and enhanced visibility.

[0004] Existing technical documents

[0005] Patent documents

[0006] Patent Document 1: Japanese Patent Application Publication No. 2021-103286 Summary of the Invention

[0007] The technical problem that the invention aims to solve

[0008] The aforementioned reduction in the weight of VR goggles can be achieved, for example, by thinning the lenses used in the VR goggles. On the other hand, it is also desirable to develop optical components for display systems that are suitable for using thin lenses.

[0009] In view of the above, the main objective of the present invention is to provide: a phase difference film, a phase difference film assembly, or a method for manufacturing a lens or display system that can achieve lightweight VR goggles while improving visibility.

[0010] Technical solutions for solving technical problems

[0011] [1] According to one aspect of the present invention, a method for manufacturing a display system is provided, the display system being used to display images to a user, wherein the display system comprises: a display element having a display surface from which light for displaying an image is emitted forward via a polarizing member; a reflective polarizing member disposed in front of the display element to reflect light emitted from the display element; a first lens portion disposed in the optical path between the display element and the reflective polarizing member, the main surface of which has a curved surface; a semi-reflective mirror disposed between the display element and the first lens portion to transmit light emitted from the display element and to reflect light reflected by the reflective polarizing member back to the reflective polarizing member; and a first phase difference member disposed between the display element and the semi-reflective mirror. The optical path between the mirrors includes a first λ / 4 component; a second phase difference component is disposed in the optical path between the semi-reflective mirror and the reflective polarizing component, and includes a second λ / 4 component. The manufacturing method includes the following steps: integrating a phase difference film containing two or more phase difference layers with an in-plane phase difference Re (550) of 100nm to 190nm, and the absolute value of the sum of the phase difference change values ​​RS of each phase difference layer being 3.0 or less, as the second phase difference component with the first lens part. Here, the phase difference change value RS is the slope of an approximate straight line of the in-plane phase difference Re (550) measured by the phase difference layer under tension of 0kg, 0.5kg, 1kg, 1.5kg and 2kg.

[0012] [2] The manufacturing method described in [1] above may include the following steps: preparing two phase difference films; integrating one of the phase difference films as the first phase difference component with the display element; and integrating the other phase difference film as the second phase difference component with the first lens portion.

[0013] [3] The manufacturing method of this embodiment of the invention is a method for manufacturing a lens portion, which is used in a display system for displaying images to a user. The lens portion includes: a reflective polarizing member that emits light forward from the display surface of a display element displaying an image and reflects the light through the polarizing member and a first λ / 4 member; a first lens portion disposed in the optical path between the display element and the reflective polarizing member, having a curved main surface; a semi-reflective mirror disposed between the display element and the first lens portion, allowing light emitted from the display element to pass through and causing light reflected by the reflective polarizing member to reflect back to the reflective polarizing member; and a second phase difference member disposed in... The manufacturing method includes the following steps: integrating a phase difference film comprising two or more phase difference layers with an in-plane phase difference Re(550) of 100nm to 190nm, and wherein the absolute value of the sum of the phase difference variation values ​​RS of each phase difference layer is 3.0 or less, as the second phase difference component with the first lens portion. Here, the phase difference variation value RS is the slope of an approximate straight line of the in-plane phase difference Re(550) measured by the phase difference layer under tensions of 0kg, 0.5kg, 1kg, 1.5kg and 2kg.

[0014] [4] The phase difference film of the present invention comprises two or more phase difference layers, and the absolute value of the total phase difference change value RS of each phase difference layer is less than 3.0. The phase difference change value RS is the slope of an approximate straight line of the in-plane phase difference Re (550) measured under the condition of applying tension of 0 kg, 0.5 kg, 1 kg, 1.5 kg and 2 kg.

[0015] [5] The phase difference film described above [4] may include a phase difference layer A, which is formed of a resin with negative birefringence and a refractive index characteristic showing the relationship nz>nx=ny.

[0016] [6] The phase difference film described in [4] or [5] above may further include another phase difference layer, wherein the ratio of the thickness of the other phase difference layer to the thickness of the phase difference layer A (the other phase difference layer / phase difference layer A) is 10 or less.

[0017] [7] In any one of the phase difference films described in [4] to [6] above, the elongation at break of the phase difference layer A at 23°C can be 1% or more.

[0018] [8] The phase difference film described in any one of [4] to [7] above may further include another phase difference layer, wherein the in-plane phase difference Re (550) of the other phase difference layer is 100 nm to 160 nm.

[0019] [9] The surface smoothness of the phase difference film described in any one of [4] to [8] above can be less than 0.4 arcmin.

[0020]

[10] The phase difference film described in any one of [4] to [9] above can be integrated with a component having a curved surface.

[0021]

[11] In the phase difference film described in

[10] above, the radius of curvature of the curved surface of the component with the curved surface can be 20 mm or more.

[0022]

[12] The phase difference film described in any one of [4] to

[11] above can be used as a second phase difference component integrated with a first lens in a display system, the display system comprising: a display element having a display surface from which light for displaying an image is emitted forward via a polarizing component; a reflective polarizing component disposed in front of the display element to reflect light emitted from the display element; a first lens disposed in the optical path between the display element and the reflective polarizing component, the main surface of which has a curved surface; a semi-reflective mirror disposed between the display element and the first lens to transmit light emitted from the display element and to reflect light reflected by the reflective polarizing component back to the reflective polarizing component; a first phase difference component disposed in the optical path between the display element and the semi-reflective mirror, comprising a first λ / 4 component; and a second phase difference component disposed in the optical path between the semi-reflective mirror and the reflective polarizing component, comprising a second λ / 4 component.

[0023]

[13] The phase difference film assembly of the present invention is an assembly in a display system comprising a first phase difference film for constituting a first phase difference component and a second phase difference film for constituting a second phase difference component. The display system includes: a display element having a display surface from which light for displaying an image is emitted forward via a polarizing member; a reflective polarizing member disposed in front of the display element to reflect light emitted from the display element; a first lens portion disposed in the optical path between the display element and the reflective polarizing member, having a curved main surface; a semi-reflective mirror disposed between the display element and the first lens portion to transmit light emitted from the display element and to reflect light reflected by the reflective polarizing member back to the reflective polarizing member; and a first phase difference component disposed between the display element and the reflective polarizing member. The optical path between the semi-reflective mirrors includes a first λ / 4 component; the second phase difference component is disposed in the optical path between the semi-reflective mirror and the reflective polarizing component and includes a second λ / 4 component. In the display system, the second phase difference component is integrated with the first lens part. The first phase difference film and the second phase difference film are each a phase difference layer containing two or more phase difference layers with an in-plane phase difference Re (550) of 100nm to 190nm, and the absolute value of the sum of the phase difference change values ​​RS of each phase difference layer is 3.0 or less. Here, the phase difference change value RS is the slope of an approximate straight line of the in-plane phase difference Re (550) measured by the phase difference layer under tension of 0kg, 0.5kg, 1kg, 1.5kg and 2kg.

[0024] Invention Effects

[0025] The method for manufacturing a phase difference film, a phase difference film assembly, or a lens portion or display system according to embodiments of the present invention can achieve good lightweighting of VR goggles while improving visibility. Attached Figure Description

[0026] Figure 1 This is a schematic diagram illustrating an example of a method for integrating a phase difference thin film with a component having a curved surface.

[0027] Figure 2 This is a schematic cross-sectional view of the phase difference thin film according to an embodiment of the present invention.

[0028] Figure 3 This is a schematic diagram illustrating a schematic representation of an example of a display system for VR goggles.

[0029] Figure 4 This is a schematic cross-sectional view and a partially enlarged cross-sectional view illustrating an example of the construction of an integrated structure of a phase difference film and a component with a curved surface.

[0030] Figure 5 This is a schematic cross-sectional view illustrating the structure of an example of an optical laminate containing a phase difference film. Detailed Implementation

[0031] Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings, but the present invention is not limited to these embodiments. For clarity, the width, thickness, shape, etc., of various parts may be schematically shown compared to the embodiments, but these are merely examples and do not limit the interpretation of the present invention. Furthermore, regarding the drawings, the same or equivalent elements are sometimes labeled with the same symbol, and repeated descriptions are omitted.

[0032] (Definitions of terms and symbols)

[0033] The terms and symbols used in this specification are defined as follows.

[0034] (1) Refractive index (nx, ny, nz)

[0035] “nx” is the refractive index in the direction of maximum in-plane refractive index (i.e., the slow axis direction), “ny” is the refractive index in the direction orthogonal to the slow axis in-plane (i.e., the fast axis direction), and “nz” is the refractive index in the thickness direction.

[0036] (2) In-plane phase difference (Re)

[0037] “Re(λ)” is the in-plane phase difference measured at 23°C with light of wavelength λnm. For example, “Re(550)” is the in-plane phase difference measured at 23°C with light of wavelength 550nm. Re(λ) is calculated using the formula: Re(λ) = (nx - ny) × d when the thickness of the layer (film) is set to d (nm).

[0038] (3) Phase difference in the thickness direction (Rth)

[0039] “Rth(λ)” is the phase difference in the thickness direction measured at 23°C with light of wavelength λnm. For example, “Rth(550)” is the phase difference in the thickness direction measured at 23°C with light of wavelength 550nm. Rth(λ) is calculated using the formula: Rth(λ) = (nx - nz) × d when the layer (film) thickness is set to d (nm).

[0040] (4) Nz coefficient

[0041] The Nz coefficient can be obtained by Nz=Rth / Re.

[0042] (5) Angle

[0043] When an angle is mentioned in this specification, the angle includes both clockwise and counterclockwise directions relative to a reference direction. Therefore, for example, "45°" means ±45°.

[0044] A. Phase retardation thin film

[0045] The phase difference film of this invention comprises two or more (preferably two) phase difference layers. In the phase difference film, the absolute value of the sum of the phase difference variation values ​​RS of each phase difference layer is 3.0 or less. In one embodiment, the phase difference film comprises a phase difference layer with an in-plane phase difference Re(550) of 100 nm to 190 nm. The phase difference film is suitable for use in an integrated manner with a component having a curved surface. The phase difference variation value "RS" is the slope of an approximate straight line of the in-plane phase difference Re(550) measured under tensions of 0 kg, 0.5 kg, 1 kg, 1.5 kg, and 2 kg, which can serve as an indicator of the degree of change in the in-plane phase difference when tension is applied to the phase difference film (resulting in a phase difference layer). Specifically, a small RS means that the in-plane phase difference is not easily changed when tension is applied to the phase difference layer. When integrated with components having curved surfaces, the retardation film is subjected to tension, resulting in a change in the phase difference of the retardation layers. However, if the absolute value of the sum of the phase difference changes RS of each retardation layer is within the aforementioned range, this phase difference change can be reduced. Additionally, dimensional changes and phase difference changes caused by heating can also be reduced.

[0046] The absolute value of the total phase difference change value RS of each phase difference layer is preferably 2.5 or less, more preferably 2.0 or less, even more preferably 1.5 or less, and most preferably 1.0 or less. Within this range, the aforementioned effect becomes significant. The smaller the absolute value of the total phase difference change value RS of each phase difference layer, the better; its lower limit is, for example, 0.5 (preferably 0.1).

[0047] The surface smoothness of the aforementioned phase retardation film is preferably 0.4 arcmin or less, more preferably 0.35 arcmin or less. Within this range, phase retardation inhomogeneity can be suppressed when integrated with components having curved surfaces. Furthermore, surface smoothness can be measured by focusing illumination light onto the surface of the object. Details are described later.

[0048] The ISC value of the aforementioned phase retardation film is, for example, 50 or less, preferably 40 or less, more preferably 30 or less, and even more preferably 20 or less. The ISC value can serve as an indicator of smoothness or unevenness. If it is within such a range, unevenness in phase retardation can be suppressed when integrated with components having curved surfaces.

[0049] The thickness deviation of the aforementioned retardation film is preferably 1µm or less, more preferably 0.8µm or less, even more preferably 0.6µm or less, and even more preferably 0.4µm or less. With such a thickness deviation, the aforementioned ISC value can be achieved well, for example. Here, the thickness deviation can be determined by measuring the thickness of a first portion located within the plane of the retardation film and the thickness at a position spaced at a predetermined interval (e.g., 5mm to 15mm) in any direction (e.g., above, below, left, and right) from the first portion.

[0050] The ISC value per unit thickness of the aforementioned phase retardation film is preferably 1 or less, more preferably 0.7 or less, and even more preferably 0.5 or less. The ISC value per unit thickness can be obtained, for example, by dividing the ISC value by the thickness (unit: µm).

[0051] As described above, the phase retardation film can be used integrated with a component having a curved surface. More specifically, the phase retardation film can be used integrated with the curved surface of the component. The curved surface can be concave or convex. The radius of curvature of the curved surface is, for example, 20 mm or more, and also, for example, 25 mm or more, and also, for example, 30 mm or more, and also, for example, 150 mm or less, preferably 125 mm or less, more preferably 110 mm or less, and may also be 90 mm or less. The diameter (major axis) of the component having the curved surface can be, for example, 20 mm to 80 mm, and also, for example, 30 mm to 70 mm. As an example of a component having a curved surface, a lens having a concave surface can be used.

[0052] The integration of the aforementioned phase difference film with the curved surface component can be carried out by any suitable method. Figure 1 This is a schematic diagram illustrating an example of a method for integrating a phase retardation thin film with a component having a curved surface. Figure 1 In (a), the phase retardation film 100 is disposed on the component L, which is the object to be adhered, in the state of a phase retardation film 3 with an adhesive layer 2 on one side. The component L is circular in plan view and has a concave shape when viewed from the top. The phase retardation film 3 with the adhesive layer can be disposed in a predetermined position by clamping its end with a fixing clamp (not shown). The phase retardation film 3 with the adhesive layer is disposed at the position where the adhesive layer 2 contacts the concave edge of the component L, and is pressed into the concave side using a clamp while being softened by heating, thereby achieving the desired effect. Figure 1 As shown in (b), the entire concave surface of component L is fitted. Then, as... Figure 1 As shown in (c), the unwanted portion of the phase difference film 3 with adhesive layer (e.g., the portion extending beyond part L in top view) is removed, thereby obtaining an integral part.

[0053] When integrated with the aforementioned curved surface, a phase retardation film can typically be stretched. For example, the phase retardation film is stretched from a planar shape corresponding to the top view shape of component L into a curved shape along the curved surface shape of component L. In this way, tension can be applied to the phase retardation film when integrated with the curved surface, and the phase difference change caused by the applied tension can be suppressed according to the aforementioned phase retardation film.

[0054] like Figure 1 As shown, when the aforementioned retardation film 100 is integrated with a component L that is circular with a radius of 32.5 mm when viewed from the concave side and has a radius of curvature of 75 mm, the maximum absolute value of the difference between Re(550) at the center 1c of the retardation film 100 and Re(550) at other parts (outside) can be, for example, less than 15 nm, less than 10 nm, or less than 8 nm, or more than 2 nm. When stretched during integration with component L, in-plane phase difference deviation may occur within the plane (within the curved surface) of the retardation film. For example, in the integrated curved retardation film, there may be a large difference between Re(550) at a portion with a large distance from the center and Re(550) at the center. Based on the aforementioned retardation film, even when stretched during integration with component L, the in-plane phase difference deviation can still be reduced.

[0055] Typically, the aforementioned retardation film 100 includes a retardation layer A whose refractive index characteristics exhibit a relationship of nz > nx = ny. The retardation layer A is a so-called positive C-plate.

[0056] The phase difference Rth (550) in the thickness direction of the retardation layer A is preferably -20nm to -200nm, more preferably -30nm to -180nm, even more preferably -40nm to -160nm, and most preferably -50nm to -140nm. Here, "nx = ny" includes not only the case where nx and ny are strictly equal, but also the case where nx and ny are substantially equal. The in-plane phase difference Re (550) of the retardation layer A is, for example, less than 10nm.

[0057] The retardation layer A is formed from any suitable material that satisfies the above-mentioned characteristics. For example, the retardation layer A can be formed from a resin film or a directionally cured layer of a liquid crystal compound. The retardation film formed from a resin film has the following advantages: excellent mechanical properties (e.g., elongation at break) and is less prone to cracking even when applied to curved surfaces.

[0058] In one embodiment, the phase retardation layer A may be formed from a resin with negative birefringence. A resin with negative birefringence is one that exhibits the property of having the highest refractive index perpendicular to the stretching direction when subjected to uniaxial stretching. Examples of resins with negative birefringence include resins with side chains incorporating highly polarized anisotropic chemical bonds or functional groups such as aromatic rings or carbonyl groups. Specific examples of resins with negative birefringence include acrylic resins, styrene resins, maleimide resins, modified polyolefin resins, and fumarate resins. For specific examples of resins with negative birefringence and methods for manufacturing positive C-plates using this resin, please refer to Japanese Patent Application Publication Nos. 2023-73125, 2021-76759, 2008-544304, and 2008-544317, which describe resins with negative birefringence and methods for manufacturing positive C-plates. The above-mentioned resin materials can be used alone or in combination of two or more.

[0059] A phase retardation layer A, formed from a resin with negative birefringence, exhibits a phase difference in a direction perpendicular to the direction of the applied tension when tension is applied. Therefore, by combining this phase retardation layer A with a phase retardation layer formed from a material with positive birefringence, the in-plane phase difference changes of the two phase retardation layers cancel each other out when stretched on a curved surface. This suppresses phase difference changes throughout the phase retardation film, thus preventing phase difference inhomogeneity. As described later, the effect becomes more pronounced when combining the λ / 4 component, which serves as another phase retardation layer, with the aforementioned phase retardation layer A.

[0060] In another embodiment, the retardation layer A is preferably composed of a film containing a liquid crystal material fixed in a vertical orientation. The liquid crystal material (liquid crystal compound) that enables vertical orientation can be a liquid crystal monomer or a liquid crystal polymer. As a specific example of the liquid crystal compound and the method for forming the positive C-plate, the liquid crystal compound and the method for forming the retardation layer described in paragraphs

[0020] to

[0028] of Japanese Patent Application Publication No. 2002-333642 can be cited.

[0061] The phase difference variation value RS of the aforementioned phase difference layer A is preferably -4.0 to 0, more preferably -3.5 to -0.3 or less, even more preferably -3.0 to -0.5 or less, particularly preferably -2.5 to -0.8 or less, and most preferably -2.3 to -1 or less. Within such a range, the aforementioned effect becomes significant.

[0062] The elongation at break of the aforementioned retardation layer A at 23°C is preferably 1% or more, more preferably 1.5% or more, and even more preferably 2.0% or more. Within this range, a retardation film that is not prone to cracking even when applied to curved surfaces can be obtained. The upper limit of the elongation at break of the aforementioned retardation layer A at 23°C is, for example, 5.0%. The method for measuring the elongation at break is described later.

[0063] The thickness of the phase retardation layer A formed from the resin film is preferably 0.5µm to 40µm, more preferably 1µm to 40µm, even more preferably 3µm to 35µm, and most preferably 5µm to 30µm. When formed as a liquid crystal orientation curing layer, the thickness of the phase retardation layer A is preferably 0.5µm to 10µm, more preferably 0.5µm to 8µm, and even more preferably 0.5µm to 5µm.

[0064] The aforementioned phase retardation film may also include another phase retardation layer. Figure 2 This is a schematic cross-sectional view of a phase retardation film according to an embodiment of the present invention. In one embodiment, the phase retardation film 100 includes a phase retardation layer A and another phase retardation layer B. The other phase retardation layer B (sometimes referred to as phase retardation layer B) can be, for example, a λ / 4 component. The other phase retardation layer can be formed from an extended film of a resin film or an orientation-cured layer of a liquid crystal compound. In one embodiment, phase retardation layer A and phase retardation layer B are laminated via an adhesive layer (adhesive layer, adhesive layer, etc.).

[0065] The in-plane phase difference Re(550) of the other phase retardation layer is, for example, 100nm~190nm, 110nm~180nm, 130nm~160nm, or 135nm~155nm. The other phase retardation layer preferably exhibits inverse wavelength dispersion characteristics, where the phase difference value increases with the wavelength of the measurement light. The Re(450) / Re(550) of the other phase retardation layer is, for example, 0.75 or more and less than 1, or 0.8 or more and less than 0.95.

[0066] The phase difference variation value RS of the other phase difference layer is preferably -2.5 to 10, more preferably -2 to 5, and most preferably -1 to 4. In one embodiment, the phase difference variation value RS of the other phase difference layer is 0 to 10, more preferably 0 to 5, and even more preferably 0 to 4. In another embodiment, the phase difference variation value RS of the other phase difference layer is preferably -2.5 to 0, more preferably -2 to 0, and most preferably -1 to 0.

[0067] The ratio of the thickness of the other phase retardation layer to the thickness of phase retardation layer A (other phase retardation layer / phase retardation layer A) is preferably 10 or less, more preferably 8 or less, even more preferably 5 or less, and most preferably 3 or less. Within this range, a phase retardation film that is less prone to phase difference unevenness can be obtained even when applied to curved surfaces. The lower limit of the ratio of the thickness of the other phase retardation layer to the thickness of phase retardation layer A (other phase retardation layer / phase retardation layer A) is, for example, 0.3.

[0068] The value calculated by (the absolute value of the total phase difference variation values ​​RS of each phase difference layer in the phase difference film) / (the ratio of the thickness of the other phase difference layer to the thickness of phase difference layer A) is preferably 0.3 or more, more preferably 0.5 or more, even more preferably 0.9 or more, and most preferably 10 or more. Within this range, a phase difference film that is less prone to phase difference inhomogeneity can be obtained even when applied to curved surfaces. For example, the upper limit of the value calculated by (the absolute value of the total phase difference variation values ​​RS of each phase difference layer in the phase difference film) / (the ratio of the thickness of the other phase difference layer to the thickness of phase difference layer A) is 20.

[0069] Resins included in the resin film constituting another retardation layer include: polycarbonate resins, polyester carbonate resins, polyester resins, polyvinyl acetal resins, polyarylate resins, cycloolefin resins, cellulose resins, polyvinyl alcohol resins, polyamide resins, polyimide resins, polyether resins, polystyrene resins, and acrylic resins. These resins can be used alone or in combination (e.g., blending, copolymerization). When the retardation film exhibits reverse wavelength dispersion characteristics, resin films containing polycarbonate resins or polyester carbonate resins (hereinafter sometimes simply referred to as polycarbonate resins) are suitable.

[0070] As long as the effects of the present invention can be achieved, any suitable polycarbonate resin can be used. For example, the polycarbonate resin comprises: structural units derived from fluorene dihydroxy compounds; structural units derived from isosorbide dihydroxy compounds; and structural units derived from at least one dihydroxy compound selected from the group consisting of alicyclic diols, alicyclic diethanols, diethylene glycol, triethylene glycol, or polyethylene glycol, and alkylene glycols or spirocyclic ethylene glycol. The polycarbonate resin preferably comprises: structural units derived from fluorene dihydroxy compounds; structural units derived from isosorbide dihydroxy compounds; structural units derived from alicyclic diethanols; and / or structural units derived from diethylene glycol, triethylene glycol, or polyethylene glycol; more preferably, it comprises: structural units derived from fluorene dihydroxy compounds; structural units derived from isosorbide dihydroxy compounds; and structural units derived from diethylene glycol, triethylene glycol, or polyethylene glycol. The polycarbonate resin may also contain structural units derived from other dihydroxy compounds as needed. Furthermore, detailed descriptions of polycarbonate resins suitable for use in phase retardation films and methods for forming phase retardation films are described, for example, in Japanese Patent Application Publication Nos. 2014-10291, 2014-26266, 2015-212816, 2015-212817, and 2015-212818, which are incorporated herein by reference.

[0071] When the phase retardation film constituting the other phase retardation layer is an extended film of the resin film, its thickness is, for example, 20µm~150µm, 30µm~100µm, 35µm~80µm, or 40µm~70µm.

[0072] The orientation-cured layer of the liquid crystal compound constituting another phase reversal layer is a layer in which the liquid crystal compound is oriented in a predetermined direction within the layer and its orientation state is fixed. Furthermore, the concept of a "oriented curing layer" includes an orientation-cured layer obtained by curing liquid crystal monomers as described later. Typically, rod-shaped liquid crystal compounds are oriented (planar orientation) in a state where they are aligned along the slow axis direction of the phase reversal film. Examples of rod-shaped liquid crystal compounds include liquid crystal polymers and liquid crystal monomers. The liquid crystal compound is preferably polymerizable. If the liquid crystal compound is polymerizable, its orientation state can be fixed by polymerizing it after orientation.

[0073] The orientation-cured layer of the aforementioned liquid crystal compound (liquid crystal orientation-cured layer) can be formed by: performing an orientation treatment on the surface of a specified substrate, applying a coating liquid containing the liquid crystal compound to the surface, orienting the liquid crystal compound in a direction corresponding to the orientation treatment, and fixing the orientation state. Any suitable orientation treatment can be used. Specifically, mechanical orientation treatment, physical orientation treatment, and chemical orientation treatment can be cited. Specific examples of mechanical orientation treatment include friction treatment and stretching treatment. Specific examples of physical orientation treatment include magnetic field orientation treatment and electric field orientation treatment. Specific examples of chemical orientation treatment include oblique vapor deposition and photo-orientation treatment. The processing conditions for each orientation treatment can be any suitable condition depending on the purpose.

[0074] The orientation of liquid crystal compounds can be performed at a temperature that allows the liquid crystal phase to be displayed, depending on the type of liquid crystal compound. Through this temperature treatment, the liquid crystal compound transforms into a liquid crystal state, and then orients itself according to the orientation treatment direction on the substrate surface.

[0075] In one embodiment, the orientation state is fixed by cooling the liquid crystal compound as described above. If the liquid crystal compound is polymerizable or crosslinkable, the orientation state is fixed by performing a polymerization or crosslinking treatment on the liquid crystal compound as described above.

[0076] The aforementioned liquid crystal compound may use any suitable liquid crystal polymer and / or liquid crystal monomer. The liquid crystal polymer and liquid crystal monomer may be used alone or in combination. Specific examples of liquid crystal compounds and methods for fabricating liquid crystal orientation-cured layers are described, for example, in Japanese Patent Application Publication No. 2006-163343, Japanese Patent Application Publication No. 2006-178389, and International Publication No. 2018 / 123551. This specification incorporates the descriptions in these publications by way of reference.

[0077] When the other phase difference layer is a liquid crystal compound orientation-cured layer, its thickness is, for example, 1µm to 10µm, preferably 1µm to 8µm, more preferably 1µm to 6µm, and even more preferably 1µm to 4µm.

[0078] In manufacturing the aforementioned retardation thin film, the relative strength (RS) of the resulting retardation layer can be altered by changing the forming materials and manufacturing conditions of each retardation layer. For example, in a resin film extension film, i.e., a retardation thin film containing a retardation layer, increasing the film thickness of the retardation layer and decreasing the elongation ratio tends to decrease the RS. Furthermore, in resin films containing polycarbonate resins, increasing the proportion of structural units derived from fluorene-based dihydroxy compounds tends to decrease the RS. On the other hand, liquid crystal alignment and curing layers, i.e., retardation thin films, can have very low RS.

[0079] The protective component typically includes a substrate. The substrate can be composed of any suitable film. Examples of materials that form the main component of the film constituting the substrate include, for example, cellulose resins such as cellulose triacetate (TAC), polyester resins, polyvinyl alcohol resins, polycarbonate resins, polyamide resins, polyimide resins, polyethersulfone resins, polysulfone resins, polystyrene resins, polynorbornene resins, cycloolefin resins, polyolefin resins, (meth)acrylic acid resins, acetate resins, etc. The thickness of the substrate is preferably 5µm to 80µm, more preferably 10µm to 40µm, and even more preferably 15µm to 35µm.

[0080] B. Display System

[0081] Figure 3 This is a schematic diagram illustrating the general configuration of a display system according to an embodiment of the present invention, schematically showing the arrangement and shape of each component of the display system. The display system 10 includes: a display element 12, a reflective polarizing member 14, a first lens portion 16 having a curved main surface, a semi-reflective mirror 18, a first phase difference member 20, a second phase difference member 22, and a second lens portion 24. The reflective polarizing member 14 is disposed on the display surface 12a side of the display element 12, i.e., in front, and reflects light emitted from the display element 12. The first lens portion 16 is disposed in the optical path between the display element 12 and the reflective polarizing member 14, and the semi-reflective mirror 18 is disposed between the display element 12 and the first lens portion 16. The first phase difference member 20 is disposed in the optical path between the display element 12 and the semi-reflective mirror 18, and the second phase difference member 22 is disposed in the optical path between the semi-reflective mirror 18 and the reflective polarizing member 14. Although not shown, from the viewpoint of improving visibility, the display system 10 may also include an absorptive polarizing member. The absorptive polarizing component can be positioned in front of the reflective polarizing component 14 such that the reflection axis of the reflective polarizing component 14 is approximately parallel to the absorption axis of the absorptive polarizing component.

[0082] Sometimes the components arranged in front, starting from the semi-reflective mirror or starting from the first lens section (in the example shown, the semi-reflective mirror 18, the first lens section 16, the second λ / 4 component 22, the reflective polarizing component 14, and the second lens section 24) are collectively referred to as the lens section (lens section 4).

[0083] The display element 12 is, for example, a liquid crystal display or an organic EL display, having a display surface 12a for displaying images. Light emitted from the display surface 12a passes through a polarizing component that may be included in the display element 12 and is then emitted as first linearly polarized light.

[0084] The first phase difference component 20 includes a first λ / 4 component, which can convert the first linearly polarized light incident on the first phase difference component 20 into the first circularly polarized light. The first phase difference component 20 can also be integrally disposed with the display element 12.

[0085] The semi-reflective mirror 18 allows light emitted from the display element 12 to pass through, and causes light reflected by the reflective polarizing member 14 to reflect back to the reflective polarizing member 14. The semi-reflective mirror 18 is integrally disposed with the first lens section 16.

[0086] The second phase difference component 22 includes a second λ / 4 component, which allows light reflected by the reflective polarizer 14 and the semi-reflective mirror 18 to pass through the reflective polarizer 14. When the second phase difference component does not include any components other than the second λ / 4 component, the second phase difference component can be equivalent to the second λ / 4 component. The second phase difference component 22 can also be integrally provided with the first lens section 16.

[0087] The first circularly polarized light emitted from the first λ / 4 component included in the first phase difference component 20 passes through the half-reflector 18 and the first lens section 16, and is converted into second linearly polarized light by the second λ / 4 component included in the second phase difference component 22. The second linearly polarized light emitted from the second λ / 4 component does not pass through the reflective polarizer 14 but is reflected back to the half-reflector 18. At this time, the polarization direction of the second linearly polarized light incident on the reflective polarizer 14 is in the same direction as the reflection axis of the reflective polarizer 14. Therefore, the second linearly polarized light incident on the reflective polarizer 14 is reflected by the reflective polarizer 14.

[0088] The second linearly polarized light reflected by the reflective polarizing component 14 is converted into second circularly polarized light by the second λ / 4 component included in the second phase difference component 22. The second circularly polarized light emitted from the second λ / 4 component is reflected by the half-reflecting mirror 18 after passing through the first lens section 16. The second circularly polarized light reflected by the half-reflecting mirror 18 passes through the first lens section 16 and is converted into third linearly polarized light by the second λ / 4 component. The third linearly polarized light is transmitted through the reflective polarizing component 14. At this time, the polarization direction of the third linearly polarized light incident on the reflective polarizing component 14 is in the same direction as the transmission axis of the reflective polarizing component 14. Therefore, the third linearly polarized light incident on the reflective polarizing component 14 is transmitted through the reflective polarizing component 14.

[0089] The light from the transmissive-reflective polarizing component 14 passes through the second lens section 24 (absorption polarizing component and second lens section 24) and enters the user's eye 26.

[0090] The absorption axis of the polarizing component included in the display element 12 and the reflection axis of the reflective polarizing component 14 can be configured to be approximately parallel to each other or approximately orthogonal. The angle formed between the absorption axis of the polarizing component included in the display element 12 and the slow axis of the first λ / 4 component is, for example, 40°~50°, 42°~48°, or approximately 45°. The angle formed between the absorption axis of the polarizing component included in the display element 12 and the slow axis of the second λ / 4 component is, for example, 40°~50°, 42°~48°, or approximately 45°.

[0091] The in-plane phase difference Re(550) of the first λ / 4 component is, for example, 100nm~190nm, 110nm~180nm, 130nm~160nm, or 135nm~155nm. The first λ / 4 component preferably exhibits inverse wavelength dispersion characteristics, where the phase difference value increases with the wavelength of the measurement light. The Re(450) / Re(550) of the first λ / 4 component is, for example, 0.75 or more and less than 1, or 0.8 or more and less than 0.95.

[0092] The in-plane phase difference Re(550) of the second λ / 4 component is, for example, 100nm~190nm, 110nm~180nm, 130nm~160nm, or 135nm~155nm. The second λ / 4 component preferably exhibits inverse wavelength dispersion characteristics, where the phase difference value increases with the wavelength of the measured light. The Re(450) / Re(550) of the second λ / 4 component is, for example, 0.75 or more and less than 1, or 0.8 or more and less than 0.95. Furthermore, unless otherwise specified, the in-plane phase difference of the second λ / 4 component is the in-plane phase difference measured at the portion corresponding to the center of the first lens portion. The center of the first lens portion can be any portion that can be considered approximately the center. For example, the center of the first lens portion can be the center of the circumcircle of its top view shape.

[0093] The absolute value of the difference between the in-plane phase difference Re(550) of the first λ / 4 component and the in-plane phase difference Re(550) of the second λ / 4 component is, for example, 3.5 nm or less, preferably 3.0 nm or less, more preferably 2.5 nm or less, even more preferably 2.0 nm or less, particularly preferably 1.5 nm or less, and most preferably 1.0 nm or less.

[0094] The in-plane phase difference Re(550) of the first λ / 4 component and the in-plane phase difference Re(550) of the second λ / 4 component 22 preferably satisfy the following equation (I) (in equation (I), (a) is the in-plane phase difference Re(550) of the first λ / 4 component, and (b) is the in-plane phase difference Re(550) of the second λ / 4 component).

[0095] ((a)-(b)) / ((a)+(b) / 2)≤0.02···(I)

[0096] More preferably, ((a)-(b)) / ((a)+(b) / 2)≤0.015, and even more preferably ((a)-(b)) / ((a)+(b) / 2)≤0.01.

[0097] In the display system 10, the second phase difference component 22 is composed of the phase difference film described in item A (specifically, a phase difference film comprising a positive C-plate, i.e., phase difference layer A, and a λ / 4 component, i.e., phase difference layer B), and is integrated with the first lens portion 16 having a curved surface. The integration of the second phase difference component 22 with the first lens portion 16 can be achieved by integrating the aforementioned phase difference film, which serves as the second phase difference component 22, with the first lens portion. The second phase difference component (the phase difference film described in item A) 22 may, for example, also include any other optical components, and is integrated with the first lens portion 16 as an optical laminate having an adhesive layer (e.g., an adhesive layer) on its outermost layer.

[0098] The radius of curvature of the curved surface of the first lens portion 16 is, for example, 20 mm or more, or for example, 25 mm or more, or for example, 30 mm or more, or for example, 150 mm or less, preferably 125 mm or less, more preferably 110 mm or less, and may also be 90 mm or less. The diameter (major axis) of the first lens portion 16 may be, for example, 20 mm to 80 mm, or for example, 30 mm to 70 mm. Furthermore, in the example shown, the second phase difference member 22 is integrated with the concave surface of the first lens portion 16, but it may also be integrated with the convex surface. There is no particular limitation on the method of integrating the second phase difference member or optical laminate with the first lens portion; for example, the same method as the method of integrating the phase difference film with the component having a curved surface described in item A can be used.

[0099] Figure 4This is a schematic cross-sectional view and an enlarged view of its main parts illustrating an example of the configuration of an integral body 200 formed by integrating an optical laminate 70 including a second phase difference member 22 (100) with a first lens portion 16. In the optical laminate 70, the second phase difference member 22 (100) is arranged such that the phase difference layer B (second λ / 4 member) is forward of the phase difference layer A (positive C plate). The optical laminate 70 also includes a second protective member 74 disposed on the phase difference layer B side of the second phase difference member 22 (100). The second phase difference member 22 (100) and the second protective member 74 are typically laminated via an adhesive layer (adhesive layer, adhesive layer, etc.). The optical laminate 70 also includes a second adhesive layer 76 on the phase difference layer A side of the second phase difference member 22 (100). The optical laminate 70 can be bonded to the first lens portion 16 via the second adhesive layer 76 in a manner that follows the concave surface 16a of the first lens portion 16.

[0100] The aforementioned second protective component typically includes a substrate. The substrate can be composed of any suitable film. Examples of materials that are the main components of the film constituting the substrate include, for example, cellulose resins such as cellulose triacetate (TAC), polyester resins, polyvinyl alcohol resins, polycarbonate resins, polyamide resins, polyimide resins, polyethersulfone resins, polysulfone resins, polystyrene resins, polynorbornene resins, cycloolefin resins, polyolefin resins, (meth)acrylic acid resins, acetate resins, etc. The thickness of the substrate is preferably 5µm to 80µm, more preferably 10µm to 40µm, and even more preferably 15µm to 35µm.

[0101] The second protective component preferably has a substrate and a surface treatment layer formed on the substrate. The second protective component with the surface treatment layer can be configured such that the surface treatment layer is located on the front side. The surface treatment layer can have any suitable function. For example, from the viewpoint of improving visibility, the surface treatment layer preferably has an anti-reflective function. In addition, the surface treatment layer may also include a hard coating. The thickness of the surface treatment layer is preferably 1µm to 20µm, more preferably 2µm to 15µm, and even more preferably 3µm to 10µm.

[0102] The adhesive constituting the second adhesive layer typically contains a (meth)acrylic polymer, a polyurethane polymer, a silicone polymer, or a rubber polymer as a base polymer. Preferably, the adhesive is a (meth)acrylic adhesive containing a (meth)acrylic polymer as a main component. The thickness of the second adhesive layer is, for example, 12 µm or more, preferably 15 µm or more, and for example, 100 µm or less, preferably 80 µm or less.

[0103] In the display system 10, the first phase difference component 20 may also be composed of the phase difference film described in item A. In this case, the first λ / 4 component (the phase difference film described in item A) 20 (100) may also be integrated with the display surface 12a of the display element 12. The display surface of the display element may be a plane. As described above, the phase difference film described in item A can suppress the phase difference unevenness that occurs when integrated with a component having a curved surface. Therefore, by setting the phase difference film described in item A as the first λ / 4 component and the second λ / 4 component, and integrating them along the plane, i.e., the display surface of the display element and the curved surface of the first lens portion, a display system with a small in-plane phase difference between the two can be appropriately obtained. In such a display system, the difference between the in-plane phase difference Re(550) at the center of the phase difference film integrated with the display element and the in-plane phase difference Re(550) at the center of the phase difference film integrated with the first lens portion is, for example, 6 nm or less, preferably 5 nm or less, more preferably 4 nm or less, and even more preferably 3.5 nm or less. For example, it can be 3.0 nm or less, 2.5 nm or less, 2.0 nm or less, 1.5 nm or less, or 1.0 nm or less.

[0104] The first λ / 4 component 20 may, for example, also include any other suitable optical components, as an optical laminate having an adhesive layer (e.g., an adhesive layer) on the outermost layer, integrated with the display element 12.

[0105] Figure 5 This is a schematic cross-sectional view illustrating an example of the configuration of an optical laminate 80 including a first phase retardation member (the phase retardation film described in item A) 20 (100). In the optical laminate 80, the first phase retardation member 20 (100) is arranged such that the phase retardation layer A (positive C-plate) is positioned forward of the phase retardation layer B (second λ / 4 member). The optical laminate includes a polarizing member 82 disposed on the side of the phase retardation layer B (second λ / 4 member) of the first phase retardation member and a protective member disposed on the phase retardation layer A (positive C-plate). The polarizing member 82 is a polarizing member that may be included in the display element 12. The optical laminate 80 also includes an adhesive layer 88 on the side of the polarizing member 82 opposite to the side where the first phase retardation member is disposed. The optical laminate 80 can be attached to the front side of the display element via the adhesive layer 88.

[0106] The aforementioned polarizing component is typically an absorptive polarizing component, which may contain a resin film (sometimes called an absorptive polarizing film) containing a dichroic substance. The thickness of the absorptive polarizing film may be, for example, 1µm or more and 20µm or less, 2µm or more and 15µm or less, 12µm or less, 10µm or less, 8µm or less, or 5µm or less.

[0107] The above-mentioned absorptive polarizing film can be made from a single layer of resin film or from a laminate of two or more layers.

[0108] In the case of a single-layer resin film, an absorptive polarizing film can be obtained by subjecting hydrophilic polymer films such as polyvinyl alcohol (PVA) films, partially formalized PVA films, and partially saponified ethylene-vinyl acetate copolymer films to dyeing treatments using dichroic substances such as iodine or dichroic dyes, stretching treatments, etc. Among these, an absorptive polarizing film obtained by dyeing a PVA film with iodine and then subjecting it to uniaxial stretching is preferred.

[0109] The aforementioned dyeing using iodine can be performed, for example, by immersing the PVA membrane in an aqueous iodine solution. The elongation ratio of the uniaxial stretching is preferably 3 to 7 times. Elongation can be performed after dyeing or simultaneously with dyeing. Alternatively, it can be performed after stretching followed by dyeing. Depending on the requirements, the PVA membrane may undergo swelling treatment, crosslinking treatment, cleaning treatment, drying treatment, etc.

[0110] Examples of laminates fabricated using two or more layers include: a laminate of a resin substrate and a PVA-based resin layer (PVA-based resin film) deposited on the resin substrate; or a laminate of a resin substrate and a PVA-based resin layer coated on the resin substrate. An absorptive polarizing film obtained using a laminate of a resin substrate and a PVA-based resin layer coated on the resin substrate can be fabricated, for example, by the following steps: coating a PVA-based resin solution onto a resin substrate and drying it to form a PVA-based resin layer on the resin substrate, thus obtaining a laminate of the resin substrate and the PVA-based resin layer; and stretching and dyeing the laminate to form an absorptive polarizing film from the PVA-based resin layer. In this embodiment, a polyvinyl alcohol-based resin layer containing a halide and a polyvinyl alcohol-based resin can be formed on one side of the resin substrate. Stretching typically includes immersing the laminate in an aqueous boric acid solution to stretch it. Furthermore, depending on the requirements, the stretching may also include air stretching of the laminate at a high temperature (e.g., above 95°C) before stretching in a boric acid aqueous solution. In this embodiment, the laminate can be subjected to a drying shrinkage treatment, in which the laminate is heated while being conveyed along its length, thereby shrinking it by more than 2% in its width direction. Typically, the manufacturing method of this embodiment includes sequentially performing an air-assisted stretching treatment, a dyeing treatment, an underwater stretching treatment, and a drying shrinkage treatment on the laminate. By introducing assisted stretching, the crystallinity of PVA can be improved even when PVA is coated onto a thermoplastic resin, achieving high optical properties. Additionally, by simultaneously improving the orientation of PVA beforehand, problems such as reduced orientation or dissolution of PVA can be prevented when immersed in water during subsequent dyeing or stretching steps, achieving high optical properties. Furthermore, when the PVA-based resin layer is immersed in a liquid, compared to the case where the PVA-based resin layer does not contain halides, the orientation disorder and reduction of polyvinyl alcohol molecules can be further suppressed. Therefore, the optical properties of the absorptive polarizing film obtained by immersing the laminate in a liquid through processing steps such as dyeing and water stretching can be improved. Furthermore, by shrinking the laminate in the width direction through a drying shrinkage process, optical properties can be improved. The resulting resin-based / absorptive polarizing film laminate can be used directly (i.e., the resin substrate can be used as a protective layer for the absorptive polarizing film), or it can be used by laminating any suitable protective layer to the release surface after peeling the resin substrate from the resin-based / absorptive polarizing film laminate, or on the surface opposite to the release surface. Detailed descriptions of the manufacturing method of the absorptive polarizing film are described, for example, in Japanese Patent Application Publication No. 2012-73580 and Japanese Patent No. 6470455. The entire contents of these publications are incorporated herein by reference.

[0111] The orthogonal transmittance (Tc) of the absorptive polarizing element (absorbent polarizing film) is preferably 0.5% or less, more preferably 0.1% or less, and even more preferably 0.05% or less. The monomer transmittance (Ts) of the absorptive polarizing element (absorbent polarizing film) is, for example, 41.0% to 45.0%, preferably 42.0% or more. The polarization degree (P) of the absorptive polarizing element (absorbent polarizing film) is, for example, 99.0% to 99.997%, preferably 99.9% or more.

[0112] The aforementioned orthogonal transmittance, single-unit transmittance, and polarization can be measured, for example, using an ultraviolet-visible spectrophotometer. Polarization P can be determined using an ultraviolet-visible spectrophotometer by measuring single-unit transmittance Ts, parallel transmittance Tp, and orthogonal transmittance Tc, and then calculated from the obtained Tp and Tc using the following formula. Furthermore, Ts, Tp, and Tc are measured using a 2-degree field of view (C light source) according to JIS Z 8701 and are Y values ​​corrected for visual sensitivity.

[0113] Polarization P (%) = {(Tp-Tc) / (Tp+Tc)} 1 / 2 ×100

[0114] The same descriptions as those for the second protective component and the second adhesive layer can be applied to the first protective component and the first adhesive layer.

[0115] C. Phase retardation film components

[0116] According to another aspect of the present invention, an assembly of two phase retardation films is provided, each of which independently comprises two or more phase retardation layers B having an in-plane phase difference Re(550) of 100 nm to 190 nm, and the absolute value of the sum of the phase difference variation values ​​RS of each phase retardation layer is 3.0 or less. The difference in in-plane phase difference Re(550) of the phase retardation layers B in the two phase retardation films included in the above assembly is, for example, 10 nm or less, preferably 5 nm or less, and more preferably 0 nm to 3 nm. Each of the two phase retardation films included in the above assembly is preferably the phase retardation film described in item A.

[0117] like Figure 4As shown, the above-described display system may include a planar first phase difference component and a curved second phase difference component. In the display system, by using one of the components of the above-described phase difference film to form the first phase difference component and the other to form the second phase difference component, even if the second phase difference component is deformed following the curvature of the first lens portion, the variation or unevenness of the in-plane phase difference of the second λ / 4 component can still be reduced. As a result, the difference in the in-plane phase difference between the first λ / 4 component and the second λ / 4 component (e.g., the absolute value of the difference in the in-plane phase difference Re(550) is ≤3.5nm) can be reduced, and a display system with excellent visibility can be appropriately obtained.

[0118] Example

[0119] The present invention will be specifically described below by way of examples, but the present invention is not limited to these examples. Furthermore, the thickness and phase difference are values ​​measured using the measurement methods described below.

[0120] <Thickness>

[0121] Thicknesses less than 10µm were measured using a scanning electron microscope (JSM-7100F, manufactured by Nippon Electron Ltd.). Thicknesses greater than 10µm were measured using a digital micrometer (KC-351C, manufactured by Anritsu Ltd.).

[0122] <Phase difference>

[0123] The in-plane phase difference at 23°C was measured using a birefringence distribution meter (manufactured by Photron, product name "KAMAKIRI X stage").

[0124] [Manufacturing Example 1] Manufacturing of Positive C Plate (I)

[0125] A liquid crystal coating solution was prepared by dissolving 20 parts by mass of a side-chain liquid crystal polymer represented by the following chemical formula (1) (where the numbers 65 and 35 represent mol% of monomer units, conveniently represented as a block polymer with a weight average molecular weight of 5000), 80 parts by mass of a polymerizable liquid crystal exhibiting a nematic liquid crystal phase (manufactured by BASF: trade name Paliocolor LC242), and 5 parts by mass of a photopolymerization initiator (manufactured by Ciba Specialty Chemicals: trade name IRGACURE 907) in 200 parts by mass of cyclopentanone.

[0126] [Chemical Formula 1]

[0127]

[0128] Then, the coating liquid was applied to the substrate film (norbornene resin film: manufactured by ZEON Corporation, Japan, trade name "ZEONEX") using a bar coater, and then heated and dried at 80°C for 4 minutes to orient the liquid crystal. The liquid crystal layer was then irradiated with ultraviolet light to harden it, thereby forming a 4µm thick phase retardation component on the substrate. The resulting phase retardation component has a refractive index of nz > nx = ny. The phase difference Rth (590) in the thickness direction of the phase retardation component (positive C plate) is 83nm.

[0129] [Manufacturing Example 2] Manufacturing of Positive C Plate (II)

[0130] In a high-pressure reactor equipped with a stirrer, cooling pipe, nitrogen inlet pipe, and thermometer, 48 parts by weight of hydroxypropyl methylcellulose (Shin-Etsu Chemical, trade name METOLOSE 60SH-50), 1560 parts by weight of distilled water, 8161 parts by weight of diisopropyl fumarate, 240 parts by weight of 3-ethyl-3-oxetanebutylmethyl acrylate, and 45 parts by weight of tributyl peroxide (a polymerization initiator) were added. After nitrogen foaming for 1 hour, the mixture was stirred and maintained at 49°C for 24 hours to carry out free radical suspension polymerization. The mixture was then cooled to room temperature, and the resulting suspension containing polymer particles was centrifuged. The obtained polymer was washed twice with distilled water and twice with methanol, and then dried under reduced pressure. The resulting fumarate resin was dissolved in a toluene-methyl ethyl ketone mixed solution (toluene / methyl ethyl ketone 50% / 50% by weight) to prepare a 20% solution. Furthermore, 5 parts by weight of tributyl trimellitate were added as a plasticizer to 100 parts by weight of fumarate resin to prepare the casting solution. The support film was a biaxially stretched polyester (polyethylene terephthalate / polyethylene isophthalate copolymer) film (75µm thick). The prepared casting solution was coated onto the support film to achieve a dried film thickness of 20µm and then dried at 140°C. The dried coating (positive C plate) had Re(550) = 0nm and Rth(550) = -83nm.

[0131] [Manufacturing Example 3] Manufacturing of λ / 4 component (I)

[0132] In a batch polymerization unit consisting of two vertical reactors equipped with stirring blades and reflux coolers controlled at 100°C, 29.60 parts by weight (0.046 mol) of bis[9-(2-phenoxycarbonylethyl)fluorene-9-yl]methane, 29.21 parts by weight (0.200 mol) of isosorbide (ISB), 42.28 parts by weight (0.139 mol) of spirocyclic ethylene glycol (SPG), 63.77 parts by weight (0.298 mol) of diphenyl carbonate (DPC), and 1.19 × 10⁻⁶ mol of calcium acetate monohydrate as a catalyst were added. -2Parts by weight (6.78 × 10) -5 (mol). After nitrogen purging under reduced pressure in the reactor, it is heated with a heating medium, and stirring begins when the internal temperature reaches 100°C. Forty minutes after the start of heating, the internal temperature is raised to 220°C, and while maintaining this temperature, pressure is reduced to 13.3 kPa within 90 minutes of reaching 220°C. The phenol vapor generated during the polymerization reaction is introduced into a 100°C reflux cooler, allowing the small amount of monomer components contained in the phenol vapor to return to the reactor. The uncondensed phenol vapor is introduced into a 45°C condenser for recovery. Nitrogen is introduced into the first reactor and temporarily restored to atmospheric pressure, then the oligomerized reaction liquid in the first reactor is transferred to the second reactor. Next, heating and depressurization are initiated in the second reactor, raising the internal temperature to 240°C and reducing the pressure to 0.2 kPa within 50 minutes. Polymerization then continues until the stirring power reaches the specified value. At the point where the specified power is reached, nitrogen is introduced into the reactor and the pressure is restored. The generated polyester carbonate resin is extruded into water and cut into bundles to obtain granules. The obtained polyester carbonate resin (granules) was vacuum dried at 80°C for 5 hours. Then, a strip resin film with a thickness of 130 μm was formed using a film forming apparatus equipped with a single-screw extruder (manufactured by Toshiba Machine Co., Ltd., cylinder set temperature: 250°C), a T-die (200 mm wide, set temperature: 250°C), a cooling roller (set temperature: 120~130°C), and a winding machine. The obtained strip resin film was stretched in the width direction at an elongation temperature of 140°C and an elongation ratio of 2.7, and then wound into a roll. This yielded a λ / 4 component with a thickness of 47 µm, a Re(590) of 140 nm, and an Nz coefficient of 1.2. Furthermore, the Re(450) / Re(550) ratio of the phase retardation layer was 0.859, exhibiting reverse wavelength dispersion characteristics.

[0133] [Manufacturing Example 4] Manufacturing of λ / 4 component (II)

[0134] 55 parts by weight of the compound shown in formula (I), 25 parts by weight of the compound shown in formula (II), and 20 parts by weight of the compound shown in formula (III) were added to 400 parts by weight of cyclopentanone (CPN), and the mixture was heated to 60°C and stirred until dissolved. The solution of the above compounds was then brought to room temperature, and 3 parts by weight of IRGACURE 907 (manufactured by BASF Japan), 0.2 parts by weight of MEGAFACE F-554 (manufactured by DIC), and 0.1 parts by weight of p-methoxyphenol (MEHQ) were added to the solution, followed by further stirring. The stirred solution was clear and homogeneous. The resulting solution was filtered through a 0.20 µm membrane filter to obtain a polymerizable composition.

[0135] Alternatively, an alignment film was coated with a polyimide solution onto a 0.7 mm thick glass substrate using spin coating. After drying at 100°C for 10 minutes, the film was baked at 200°C for 60 minutes. The resulting film was then subjected to friction treatment using a commercially available friction device to form an alignment film.

[0136] Next, the polymeric composition obtained above was coated onto a substrate (essentially an oriented film) using spin coating and dried at 100°C for 2 minutes. After cooling the resulting coated film to room temperature, it was then subjected to a high-pressure mercury lamp at 30 mW / cm². 2 Irradiation with ultraviolet light at an intensity of 30 seconds yielded a phase retardation layer (thickness: 3µm) serving as the orientation-cured layer for the liquid crystal compound. The in-plane phase difference Re(590) of the phase retardation layer was 140nm. Furthermore, the Re(450) / Re(550) ratio of the phase retardation layer was 0.851, exhibiting inverse wavelength dispersion characteristics. This phase retardation layer can function as a λ / 4 component.

[0137] [Chemical Formula 1]

[0138]

[0139] [Chemical Formula 2]

[0140]

[0141] [Example 1]

[0142] A phase difference film was obtained by laminating the λ / 4 component (I) obtained in Example 3 and the positive C plate (II) obtained in Example 2 using an acrylic adhesive (thickness 5µm).

[0143] [Example 2]

[0144] A phase difference film was obtained by laminating the λ / 4 component (II) obtained in Example 4 with the positive C plate (I) obtained in Example 1 using an acrylic adhesive (thickness 5µm).

[0145] [Example 3]

[0146] A phase difference film was obtained by laminating the λ / 4 component (II) obtained in Example 4 with the positive C plate (II) obtained in Example 2 using an acrylic adhesive (thickness 5µm).

[0147] [Comparative Example 1]

[0148] As in manufacturing example 3, a phase difference film (λ / 4 component (I)) is obtained.

[0149] [Comparative Example 2]

[0150] A phase difference film was obtained by laminating the λ / 4 component (I) obtained in Example 3 with an acrylic adhesive (thickness 5µm) and the positive C plate (I) obtained in Example 1.

[0151] <Phase difference change value RS>

[0152] For the phase difference layers constituting the phase difference thin film in the embodiments and comparative examples, the phase difference change value RS was measured by the following methods.

[0153] A phase retardation layer was bonded to an acrylic film (Re(550)≈0nm) via an acrylic adhesive layer (5µm thick) to obtain a laminate. The resulting laminate was cut into samples with a length of 150mm and a width of 15mm, with the slow axis of the phase retardation film as the length direction. Furthermore, the acrylic film described above is a film that will hardly produce a phase retardation change when subjected to the following tension.

[0154] Tension was applied along the length of the obtained sample using a tension gauge (manufactured by MYCARBON, product name "Digital Luggage Scale"). At tension levels of 0 kg, 0.5 kg, 1 kg, 1.5 kg, and 2 kg, the in-plane phase difference (Re(550)) was measured using a phase difference measuring device (manufactured by Axometrics, product name: Axo Scan). The tension was set as the x-axis, and Re(550) as the y-axis. An approximate straight line was plotted using the Re(550) values ​​measured at each tension, and the slope of this approximate straight line was taken as the phase difference change value RS.

[0155] Elongation at break

[0156] The elongation at break of the positive C-plate (strip shape, 4 mm wide) constituting the phase difference film of the examples and comparative examples was measured using a thermomechanical analysis apparatus (TMA, trade name "TMA Q400", manufactured by TA Instruments) under the conditions of a measurement temperature of 23°C, a clamping distance of 8 mm, and a tensile speed of 0.1 strain / min. The elongation at the time point at which the sample breaks was evaluated was taken as the elongation at break.

[0157] <Fabrication and Evaluation of Integrated Curved Surfaces>

[0158] 1.1 Fabrication of a lens with a phase retardation thin film

[0159] An acrylic adhesive layer (15µm thick) is provided on the surface of the phase retardation film obtained in the examples and comparative examples (in example and comparative example 2, the phase retardation layer A (positive C plate) side of the phase retardation film). This adhesive layer is then bonded to the concave surface of a lens that is circular in shape (65mm in diameter, viewed from above) and has a concave surface with a radius of curvature of 75mm. Specifically, as... Figure 1As shown, a phase retardation film with an adhesive layer is mounted such that the surface of the adhesive layer contacts the concave edge of the lens, and then pressed into the concave side while being heated to 120°C to soften it, thereby adhering it to the concave surface of the lens. This results in an integrated assembly of the phase retardation film and the lens, i.e., a lens with a phase retardation film.

[0160] 1-2. Measurement of phase difference inhomogeneity

[0161] Regarding the lenses with phase difference films obtained in the embodiments and comparative examples, the in-plane phase difference Re(543) is measured over the entire surface of the phase difference film. In the resulting in-plane phase difference distribution, the difference between the in-plane phase difference Re(543) at the center and the portion outside (outside) is detected, and the maximum value of this difference is taken as the in-plane phase difference non-uniformity. Furthermore, regarding the in-plane phase difference non-uniformity (|Re(543) center - Re(543) outside|), a difference greater than 15 nm can be evaluated as "poor (×)", a difference greater than 10 nm and less than 15 nm can be evaluated as "acceptable (△)", and a difference less than 10 nm can be evaluated as "good (○)".

[0162] 2-1. Fabrication of a lens with a phase retardation film

[0163] An acrylic adhesive layer (15µm thick) is provided on one side of the phase difference film obtained in the embodiments and comparative examples, and the film is bonded to the concave surface of a lens that is circular in shape with a diameter of 50mm and a radius of curvature of 40mm when viewed from above, via this adhesive layer. Specifically, as Figure 1 As shown, a phase retardation film with an adhesive layer is mounted such that the surface of the adhesive layer is in contact with the concave edge of the lens, and then pressed into the concave side while being heated to 120°C to soften it, thereby adhering it to the concave surface of the lens. This results in an integrated assembly of the phase retardation film and the lens, i.e., a lens with a phase retardation film.

[0164] 2-2. Crack Evaluation

[0165] The lens with the phase difference film is visually inspected to determine if there are any cracks.

[0166] Smoothness

[0167] The smoothness of the phase retardation film was determined using a phase-shifting laser interferometer (Zygo Corporation, product name "DynaFiz"). Specifically, the phase retardation film was attached to a glass slide (Matsunami Glass Industry Co., Ltd., product name "S200200") in a manner that prevented foreign objects, air bubbles, or deformable streaks from entering. Next, to remove the influence of microbubbles, degassing was performed using a pressure degassing device (autoclave). The degassing conditions were set at 50°C, 0.5 MPa, and 30 minutes. After degassing, the sample was allowed to cool naturally at room temperature for at least 30 minutes to obtain the test sample.

[0168] The test sample was placed on a measuring stage equipped with a vibration damping table. A single-wavelength laser (wavelength 633nm) was used to interfere with a reference device whose flatness had been ensured, and the relative displacement within a specified area (a circle with a diameter of 30mmφ) was measured. Regarding the resolution, the smoothness of the phase difference film (unit: arcmin) was defined by multiplying the angle index "Slope magnitude RMS" obtained by selecting values ​​from 0.1 / mm to 1 / mm by 2.

[0169] The results are listed in Table 1.

[0170] [Table 1]

[0171]

[0172]

[0173] Industrial availability

[0174] The phase difference film of the present invention can be used in displays such as VR goggles.

[0175] Explanation of reference numerals in the attached figures

[0176] 10: Display System

[0177] 12: Display element

[0178] 14: Reflective polarizing component

[0179] 16: First lens section

[0180] 18: Semi-reflective mirror

[0181] 20: First λ / 4 component

[0182] 22: Second λ / 4 component

[0183] 24: Second lens section

[0184] 100: Phase retardation thin film

[0185] A: Phase difference layer A

[0186] B: Phase difference layer B

Claims

1. A manufacturing method for a display system for displaying images to a user, characterized in that, The display system includes: A display element having a display surface from which light for displaying an image is emitted forward via a polarizing component; A reflective polarizing component is disposed in front of the display element to reflect light emitted from the display element; A first lens portion is disposed in the optical path between the display element and the reflective polarizing component, and its main surface has a curved surface; A semi-reflective mirror is disposed between the display element and the first lens portion, allowing light emitted from the display element to pass through and causing light reflected by the reflective polarizing component to reflect back to the reflective polarizing component; A first phase difference component, disposed in the optical path between the display element and the semi-reflective mirror, includes a first λ / 4 component; The second phase difference component, disposed in the optical path between the semi-reflective mirror and the reflective polarizing component, includes a second λ / 4 component. The manufacturing method includes the following steps: A phase difference film comprising two or more phase difference layers with an in-plane phase difference Re(550) of 100nm to 190nm, and wherein the absolute value of the sum of the phase difference change values ​​RS of each phase difference layer is 3.0 or less, is integrated with the first lens portion as the second phase difference component. Here, the phase difference change value RS is the slope of an approximate straight line of the in-plane phase difference Re(550) measured by the phase difference layer under tensions of 0kg, 0.5kg, 1kg, 1.5kg and 2kg.

2. The manufacturing method as described in claim 1, characterized in that, Includes the following steps: Prepare two phase difference films; The phase difference film is integrated with the display element as the first phase difference component; Another phase difference film is integrated with the first lens portion as the second phase difference component.

3. A manufacturing method for a lens portion of a display system for displaying images to a user, characterized in that, The lens portion includes: A reflective polarizing component that emits light forward from the display surface of the display element displaying the image and is reflected by the polarizing component and the first λ / 4 component; A first lens portion is disposed in the optical path between the display element and the reflective polarizing component, and its main surface has a curved surface; A semi-reflective mirror is disposed between the display element and the first lens portion, allowing light emitted from the display element to pass through and causing light reflected by the reflective polarizing component to reflect back to the reflective polarizing component; The second phase difference component is disposed in the optical path between the semi-reflective mirror and the reflective polarizing component and includes a second λ / 4 component. The manufacturing method includes the following steps: A phase difference film comprising two or more phase difference layers with an in-plane phase difference Re(550) of 100nm to 190nm, and wherein the absolute value of the sum of the phase difference change values ​​RS of each phase difference layer is 3.0 or less, is integrated with the first lens portion as the second phase difference component. Here, the phase difference change value RS is the slope of an approximate straight line of the in-plane phase difference Re(550) measured by the phase difference layer under tensions of 0kg, 0.5kg, 1kg, 1.5kg and 2kg.

4. A phase retardation thin film, characterized in that, It contains two or more phase difference layers. The absolute value of the sum of the phase difference changes RS of each phase difference layer is less than 3.

0. The phase difference change value RS is the slope of an approximate straight line of the in-plane phase difference Re (550) measured under tensions of 0 kg, 0.5 kg, 1 kg, 1.5 kg and 2 kg.

5. The phase retardation thin film as described in claim 4, characterized in that, It includes a phase retardation layer A, which is formed of a resin with negative birefringence and a refractive index characteristic showing the relationship nz>nx=ny.

6. The phase retardation thin film as described in claim 5, characterized in that, It also contains another phase difference layer. The ratio of the thickness of the other phase difference layer to the thickness of the phase difference layer A, i.e., the ratio of the other phase difference layer to the phase difference layer A, is less than 10.

7. The phase retardation thin film as described in claim 5, characterized in that, The phase difference layer A has a fracture elongation of more than 1% at 23°C.

8. The phase retardation thin film as described in claim 4, characterized in that, It also contains another phase difference layer. The in-plane phase difference Re(550) of the other phase difference layer is 100nm~160nm.

9. The phase retardation thin film as described in claim 4, characterized in that, The surface smoothness is below 0.4 arcmin.

10. The phase retardation thin film as claimed in claim 4, characterized in that, Integrate with components that have curved surfaces.

11. The phase retardation thin film as claimed in claim 10, characterized in that, The radius of curvature of the curved surface of the component is 20 mm or more.

12. The phase retardation thin film as claimed in claim 4, characterized in that, It is used as a second phase difference component integrated with the first lens unit in the display system. The display system includes: A display element having a display surface from which light for displaying an image is emitted forward via a polarizing component; A reflective polarizing component is disposed in front of the display element to reflect light emitted from the display element; A first lens portion is disposed in the optical path between the display element and the reflective polarizing component, and its main surface has a curved surface; A semi-reflective mirror is disposed between the display element and the first lens portion, allowing light emitted from the display element to pass through and causing light reflected by the reflective polarizing component to reflect back to the reflective polarizing component; A first phase difference component, disposed in the optical path between the display element and the semi-reflective mirror, includes a first λ / 4 component; The second phase difference component, which is disposed in the optical path between the semi-reflective mirror and the reflective polarizing component, includes a second λ / 4 component.

13. An assembly of a phase retardation film, which in a display system comprises a first phase retardation film for constituting a first phase retardation component and a second phase retardation film for constituting a second phase retardation component. The display system includes: A display element having a display surface from which light for displaying an image is emitted forward via a polarizing component; A reflective polarizing component is disposed in front of the display element to reflect light emitted from the display element; A first lens portion is disposed in the optical path between the display element and the reflective polarizing component, and its main surface has a curved surface; A semi-reflective mirror is disposed between the display element and the first lens portion, allowing light emitted from the display element to pass through and causing light reflected by the reflective polarizing component to reflect back to the reflective polarizing component; A first phase difference component is disposed in the optical path between the display element and the semi-reflective mirror and includes a first λ / 4 component; The second phase difference component is disposed in the optical path between the semi-reflective mirror and the reflective polarizing component and includes a second λ / 4 component. In the display system, the second phase difference component is integrated with the first lens portion, characterized in that... The first phase difference film and the second phase difference film are each phase difference layers containing two or more phase difference layers with an in-plane phase difference Re (550) of 100nm to 190nm, and the absolute value of the sum of the phase difference change values ​​RS of each phase difference layer is 3.0 or less. Here, the phase difference change value RS is the slope of an approximate straight line of the in-plane phase difference Re (550) measured by the phase difference layer under tension of 0kg, 0.5kg, 1kg, 1.5kg and 2kg.

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