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

Abstract

Provided is a method for manufacturing a display system (10) that displays an image to a user, the display system (10) being provided with: a display element (12) having a display surface that emits light that displays the image forward via a polarizing member; a reflective polarizing member (14) that is disposed in front of the display element (12) and reflects light emitted from the display element (12); a first lens unit (16) which is disposed on an optical path between the display element (12) and the reflective polarizing member (14), and which has a curved main surface; a half mirror (18) that is disposed between the display element (12) and the first lens unit (16), transmits light emitted from the display element (12), and reflects light reflected by the reflective polarizing member (14) to the reflective polarizing member (14); a first [lambda] / 4 member (20) disposed on an optical path between the display element (12) and the half mirror (18); a second [lambda] / 4 member (22) disposed on an optical path between the half mirror (18) and the reflective polarizing member (14); the manufacturing method includes a step in which a retardation film having an in-plane retardation Re (550) of 100 nm to 190 nm and an absolute value of a retardation change value RS of 2.0 or less is integrated with the first lens section (16) as the second [lambda] / 4 member (22), and the second [lambda] / 4 member (22) and the second lens section (16) are integrally formed with each other. 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 tension of 0 kg, 0.5 kg, 1 kg, 1.5 kg, and 2 kg is applied to the phase difference film.

Description

Technical Field

[0001] This invention relates to a method for manufacturing a phase retardation film, a phase retardation film sheet, a phase retardation film assembly, or a lens portion or display system. Background Technology

[0002] Image display devices, represented by liquid crystal displays and electroluminescent (EL) displays (such as organic EL displays), are rapidly gaining popularity. 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 method for manufacturing a lightweight phase retardation film, a phase retardation film sheet, a phase retardation film assembly, or a lens portion or display system that can effectively improve visibility while achieving lightweight VR goggles.

[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 displaying an image to a user, wherein the display system comprises: a display element having a display surface from which light displaying the 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; and 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; A first λ / 4 component is disposed in the optical path between the display element and the semi-reflective mirror; a second λ / 4 component is disposed in the optical path between the semi-reflective mirror and the reflective polarizing component. The manufacturing method includes the following steps: a phase difference film with an in-plane phase difference Re (550) of 100nm to 190nm and an absolute value of 2.0 or less of the phase difference change value RS is used as the second λ / 4 component and integrated 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 film 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 phase difference film as the first λ / 4 component with the display element, and integrating the other phase difference film as the second λ / 4 component with the first lens portion.

[0013] [3] According to another aspect of the present invention, a method for manufacturing a lens portion is provided, the lens portion being used in a display system for displaying images to a user, wherein the lens portion comprises: a reflective polarizing member that reflects light emitted forward from the display surface of a display element displaying an image and passing 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; and 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 allowing light reflected by the reflective polarizing member to pass through the display element. The reflective polarizing component reflects light; a second λ / 4 component is disposed in the optical path between the semi-reflective mirror and the reflective polarizing component. The manufacturing method includes the following steps: a phase difference film with an in-plane phase difference Re (550) of 100nm~190nm and an absolute value of 2.0 or less of the phase difference change value RS is used as the second λ / 4 component and integrated 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 film under tension of 0kg, 0.5kg, 1kg, 1.5kg and 2kg.

[0014] [4] According to another aspect of the present invention, a phase difference film is provided, wherein the in-plane phase difference Re (550) is 100nm~190nm and the absolute value of the phase difference change value RS is 2.0 or less. The phase difference change value RS is the slope of an approximate straight line of the in-plane phase difference Re (550) measured under tension of 0kg, 0.5kg, 1kg, 1.5kg and 2kg.

[0015] [5] In the phase difference film described above [4], the in-plane phase differences Re(450), Re(550) and Re(650) can satisfy the following relationships (i)~(iii):

[0016] (i) 100nm <Re(550)<160nm、

[0017] (ii)Re(450) / Re(550)<1.1,

[0018] (iii) Re(650) / Re(550)>0.9.

[0019] [6] In the phase difference film described in [4] or [5] above, the dimensional change rate before and after heat treatment at 85°C for 500 hours is preferably less than 0.02%.

[0020] [7] In any one of the phase difference films described in [4] to [6] above, the absolute value of the difference between the in-plane phase difference Re (550) before and after heat treatment at 85°C for 500 hours is preferably 3.5 nm or less.

[0021] [8] The phase difference film described in any one of [4] to [7] above can be integrated with a component having a curved surface.

[0022] [9] In the phase difference film described in [8] above, the radius of curvature of the surface is preferably 20 mm or more.

[0023]

[10] In any one of the phase difference films described in [4] to [9] above, after being integrated with a component having a top view shape of a radius of 32.5 mm and a curvature radius of 75 mm, the absolute value of the difference between the in-plane phase difference Re (550) of the central part and the in-plane phase difference Re (550) of the part other than the central part is preferably 10 nm or less.

[0024]

[11] In any of the phase difference films of [4] to

[10] above, the display system is used as a second λ / 4 component integrated with the first lens portion, the display system comprising: 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, and having a curved surface on its 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; a first λ / 4 component disposed in the optical path between the display element and the semi-reflective mirror; and a second λ / 4 component disposed in the optical path between the semi-reflective mirror and the reflective polarizing member.

[0025]

[12] According to another aspect of the present invention, a phase difference film is provided having a curved surface, wherein the absolute value of the difference between the in-plane phase difference Re(550) at the central portion of the curved surface and the in-plane phase difference Re(550) at the portion other than the central portion is 10 nm or less.

[0026]

[13] According to a further aspect of the present invention, an assembly of a phase retardation film is provided, which is an assembly of a first phase retardation film for constituting a first λ / 4 component and a second phase retardation film for constituting a second λ / 4 component 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 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 λ / 4 component disposed between the display element and the first lens portion. In the optical path between the semi-reflective mirrors; a second λ / 4 component, which is disposed in the optical path between the semi-reflective mirror and the reflective polarizing component, in the display system, the second λ / 4 component and the first lens part are integrated, characterized in that the first phase difference film and the second phase difference film are each a phase difference film with an in-plane phase difference Re (550) of 100nm~190nm and an absolute value of 2.0 or less for the phase difference change value RS, wherein 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 film under tension of 0kg, 0.5kg, 1kg, 1.5kg and 2kg, and the absolute value of the difference between the in-plane phase difference Re (550) of the first phase difference film and the in-plane phase difference Re (550) of the second phase difference film is 5nm or less.

[0027] Invention Effects

[0028] The manufacturing method of the phase difference film, phase difference film sheet, phase difference film assembly, or lens portion or display system according to embodiments of the present invention can achieve lightweight VR goggles while improving visibility. Attached Figure Description

[0029] 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.

[0030] Figure 2 (a) is a schematic cross-sectional view illustrating the method for measuring the ellipticity when the phase difference film is integrated with a component having a curved surface, and (b) is a schematic view of the state of (a) as observed from the phase difference film side.

[0031] Figure 3 This is a schematic diagram illustrating a schematic representation of an example of a display system for VR goggles.

[0032] 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.

[0033] Figure 5 This is a schematic cross-sectional view illustrating the structure of an example of an optical laminate containing a phase difference film.

[0034] Figure 6 This is a diagram used to illustrate the method for measuring thickness deviation.

[0035] Figure 7 This is a diagram used to illustrate the method for determining ISC values. Detailed Implementation

[0036] 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.

[0037] (Definitions of terms and symbols)

[0038] The terms and symbols used in this specification are defined as follows.

[0039] (1) Refractive index (nx, ny, nz)

[0040] “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.

[0041] (2) In-plane phase difference (Re)

[0042] “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).

[0043] (3) Phase difference in the thickness direction (Rth)

[0044] “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).

[0045] (4) Nz coefficient

[0046] The Nz coefficient can be obtained by Nz = Rth / Re.

[0047] (5) Angle

[0048] When the angle is mentioned in this specification, the angle includes both the clockwise direction (+) and the counterclockwise direction (-) relative to the reference direction. Therefore, for example, "45°" means ±45°.

[0049] A. Phase difference film

[0050] According to one aspect of the present invention, there is provided a phase difference film having an absolute value of the phase difference change value RS of 2.0 or less. The above-mentioned phase difference film is suitable for use in a state integrated with a component having a curved surface. The phase difference change value "RS" is the slope of the approximate straight line of the in-plane phase difference Re(550) measured in the state where tensions of 0 kg, 0.5 kg, 1 kg, 1.5 kg and 2 kg are applied to the phase difference film, and can be an index of the degree of change of the in-plane phase difference when tension is applied to the phase difference film. Specifically, a small absolute value of RS means that the in-plane phase difference is not easily changed when tension is applied to the phase difference film. When integrated with a component having a curved surface, tension is applied to the phase difference film, and as a result, the phase difference changes. However, if the absolute value of RS is within the above range, the change in the phase difference can be suppressed. In addition, the dimensional change and the phase difference change caused by heating can also be suppressed. The absolute value of RS can be, for example, 1.80 or less or 1.50 or less, and can be, for example, 0.05 or more.

[0051] The above-mentioned phase difference film preferably has a refractive index characteristic showing a relationship of nx > ny ≥ nz. Here, "ny = nz" includes not only the case where ny and nz are exactly the same, but also the case where they are substantially the same. Therefore, there may be a case where ny < nz within the range that does not impair the effects of the present invention. The Nz coefficient of the phase difference film is preferably 0.9 to 3, more preferably 0.9 to 2.5, further preferably 0.9 to 1.5, and most preferably 0.9 to 1.3.

[0052] The in-plane phase difference Re(550) of the above-mentioned phase difference film is, for example, 100 nm to 190 nm, can be 110 nm to 180 nm, can also be 130 nm to 160 nm, and can further be 135 nm to 155 nm. In one embodiment, the above-mentioned phase difference film satisfies the relationship of 100 nm < Re(550) < 160 nm.

[0053] The aforementioned phase retardation film can exhibit either inverse wavelength dispersion characteristics where the phase difference increases with the wavelength of the measurement light, or flat wavelength dispersion characteristics where the phase difference value hardly changes with the wavelength of the measurement light. The Re(450) / Re(550) ratio of the phase retardation film is, for example, less than 1.1, and can be less than 1, less than 0.95, less than 0.90, or less than 0.85. The Re(450) / Re(550) ratio of the phase retardation film is, for example, greater than 0.75. The Re(650) / Re(550) ratio of the phase retardation film is, for example, greater than 0.9, and can be greater than 1, greater than 1 and less than 1.2, or 1.01 to 1.15. Using a phase retardation film exhibiting inverse wavelength dispersion characteristics or flat wavelength dispersion characteristics can help improve visibility when applied to display systems such as VR goggles.

[0054] When linearly polarized light, whose polarization direction is at a 45° angle to its slow axis, is incident from the normal direction relative to the aforementioned retardation film, the ellipticity of the transmitted light with a wavelength of 550 nm, measured at a polar angle of 0° (normal direction), is, for example, 0.80 or more, preferably 0.85 or more, and more preferably 0.90 to 1. Ellipticity is the ratio of the minor axis to the major axis of circularly polarized light; for example, the ellipticity is 1 for perfectly circularly polarized light and 0 for perfectly linearly polarized light. A retardation film exhibiting the aforementioned ellipticity can help improve visibility when applied to display systems such as VR goggles.

[0055] The dimensional change rate ((size before heat treatment - size after heat treatment) / size before heat treatment × 100) of the aforementioned phase retardation film after heat treatment at 85°C for 500 hours is, for example, 0.02% or less, or even 0.015% or less, or 0.01% or less. Based on the phase retardation film exhibiting the aforementioned dimensional change rate, when used as a laminate with other components, it has the advantage of being less prone to peeling due to heating.

[0056] When the aforementioned phase retardation film is used for heat treatment at 85°C for 500 hours, the difference in in-plane phase difference Re(550) before and after heat treatment (|Re(550) before heat treatment - Re(550) after heat treatment|) is, for example, less than 3.5 nm, or less than 3 nm, less than 2 nm, less than 1 nm, or less than 0.5 nm. If a phase retardation film displaying the aforementioned in-plane phase difference is used, when applied to display systems such as VR goggles, the reduction in visibility caused by heating can be suppressed.

[0057] 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. A phase retardation film that satisfies such an ISC value and the absolute value of the aforementioned RS can suppress phase difference unevenness when integrated with a component having a curved surface.

[0058] 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.

[0059] 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).

[0060] 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.

[0061] 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 1 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 when viewed from above and has a concave shape when viewed from above. 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 is in contact with 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 1As 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.

[0062] When integrated with the aforementioned curved surface, the retardation film can typically be stretched. For example, the retardation film can be stretched from a planar shape (circle) 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 retardation film when integrated with the curved surface, and according to the aforementioned retardation film, since the absolute value of RS is small, the phase difference change caused by the applied tension can be suppressed.

[0063] like Figure 2 As shown, the aforementioned retardation film 1 is integrated with a component L, which is circular with a radius of 32.5 mm when viewed from the concave side and has a radius of curvature of 75 mm on the concave surface. When linearly polarized light with a polarization direction at a 45° angle to its slow axis is incident from the convex side in the normal direction relative to the center C of component L (in other words, the center 1c of retardation film 1), the difference between the ellipticity of the transmitted light with a wavelength of 550 nm measured on the concave side in the normal direction and the ellipticity of the portion corresponding to the center 1c of the retardation film 1 before integration (ellipticity before integration - ellipticity after integration) is, for example, 0.06 or less, preferably 0.05 or less, and more preferably 0 to 0.04. With such a retardation film, when used in a display system integrated with a component having a curved surface, it can help improve display characteristics.

[0064] like Figure 2 As shown, when the aforementioned retardation film 1 is integrated with the aforementioned component L, the difference between Re(550) at the center portion 1c of the integrated curved retardation film 1 and the Re(550) at the corresponding portion of the retardation film before integration (|Re(550) before integration - Re(550) after integration|) is, for example, 6 nm or less, preferably 5 nm or less, and more preferably 4 nm or less. With such a retardation film, when used in a display system integrated with a curved component, it can help improve display characteristics.

[0065] like Figure 2As shown, when the phase retardation film 1 is integrated with the component L, the maximum absolute value of the difference between Re(550) at the center 1c of the phase retardation film 1 and Re(550) at other parts (outside) can be, for example, less than 15 nm, less than 10 nm, or less than 6 nm, or more than 0.5 nm. When stretched during integration with the component L, in-plane phase difference deviation may occur within the plane (within the curved surface) of the phase retardation film. For example, in the integrated curved phase retardation film, there is a case where the difference between Re(550) at the portion with a large distance from the center and Re(550) at the center is large. According to the phase retardation film having the absolute value of RS, even when stretched during integration with the component L, the in-plane phase difference deviation can still be reduced.

[0066] like Figure 2 As shown, after integrating the aforementioned retardation film 1 with the aforementioned component L, when linearly polarized light with its polarization direction at a 45° angle to its slow axis is incident from the convex side in the normal direction relative to component L, the maximum absolute value of the difference between the ellipticity of the central portion 1c of the retardation film 1 and the ellipticity of its other portions (outer parts) and the ellipticity of the transmitted light with a wavelength of 550 nm measured on the concave side in the normal direction is, for example, 0.07 or less, preferably 0.06 or less, and more preferably 0 to 0.05. With such a retardation film, when used in a display system integrated with a component having a curved surface, it can help improve display characteristics.

[0067] The aforementioned phase retardation film is formed from any suitable material that satisfies the above characteristics. The phase retardation film can be, for example, an extended film of a resin film or a oriented cured layer of a liquid crystal compound.

[0068] Examples of resins included in the aforementioned resin films include: polycarbonate resins, polyester carbonate resins, polyester resins, polyvinyl acetal resins, polyaryl ester 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). Among these, resin films containing cycloolefin resins are particularly suitable.

[0069] The aforementioned cyclic olefin resins may, for example, be suitable for use with polynorbornene. Polynorbornene refers to a (co)polymer obtained by using a portion or all of the starting materials (monomers) with norbornene monomers having a norbornene ring.

[0070] The aforementioned polynorbornene is available in various commercial products. Specific examples include the products manufactured by ZEON Corporation under the brand names "ZEONEX" and "Zeonor", JSR Corporation under the brand name "Arton", TICNA Corporation under the brand name "TOPAS", and Mitsui Chemicals Corporation under the brand name "APEL".

[0071] When the aforementioned phase difference film is an extension of the resin film, its thickness is, for example, 10µm to 100µm, preferably 10µm to 70µm, more preferably 10µm to 60µm, and even more preferably 20µm to 50µm.

[0072] The aforementioned orientation-cured layer of the liquid crystal compound 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 "orientation-cured layer" includes orientation-cured layers 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 retardation 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 aforementioned phase difference film is an orientation-cured layer of a liquid crystal compound, 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 film, the RS (Resolution Range) of the resulting retardation film can be altered by changing the forming materials, manufacturing conditions, etc. For example, in the elongation film of a resin film, i.e., the retardation film, there is a tendency for the absolute value of RS to decrease by reducing the elongation ratio, etc. On the other hand, the absolute value of RS in the liquid crystal alignment and curing layer, i.e., the retardation film, tends to be very small.

[0079] B. Display System

[0080] Figure 3 This is a schematic diagram showing the general configuration of a display system according to one embodiment of the present invention, schematically illustrating the arrangement and shape of the various components 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 λ / 4 member 20, a second λ / 4 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 λ / 4 member 20 is disposed in the optical path between the display element 12 and the semi-reflective mirror 18, and the second λ / 4 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.

[0081] 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).

[0082] 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.

[0083] The first λ / 4 component 20 can convert the first linearly polarized light incident on the first λ / 4 component 20 into the first circularly polarized light. The first λ / 4 component 20 can also be integrated with the display element 12.

[0084] 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.

[0085] The second λ / 4 component 22 allows light reflected by the reflective polarizing component 14 and the semi-reflective mirror 18 to be transmitted through the reflective polarizing component 14. The second λ / 4 component 22 is integrally provided with the first lens section 16.

[0086] The first circularly polarized light emitted from the first λ / 4 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 22. The second linearly polarized light emitted from the second λ / 4 component 22 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.

[0087] 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 22. The second circularly polarized light emitted from the second λ / 4 component 22 passes through the first lens section 16 and is reflected by the half-reflecting mirror 18. 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 22. 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.

[0088] The light from the transmissive-reflective polarizing component 14 passes through the second lens section 24 (absorption-type polarizing component 28 and second lens section 24) and enters the user's eye 26.

[0089] 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 by the absorption axis of the polarizing component included in the display element 12 and the slow axis of the first λ / 4 component 20 is, for example, 40°~50°, 42°~48°, or approximately 45°. The angle formed by the absorption axis of the polarizing component included in the display element 12 and the slow axis of the second λ / 4 component 22 is, for example, 40°~50°, 42°~48°, or approximately 45°.

[0090] The in-plane phase difference Re(550) of the first λ / 4 component 20 is, for example, 100nm~190nm, 110nm~180nm, 130nm~160nm, or 135nm~155nm. The first λ / 4 component 20 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 first λ / 4 component 20 is, for example, 0.75 or more and less than 1, or 0.8 or more and less than 0.95.

[0091] The in-plane phase difference Re(550) of the second λ / 4 component 22 is, for example, 100nm~190nm, 110nm~180nm, 130nm~160nm, or 135nm~155nm. The second λ / 4 component 22 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 22 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 a 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.

[0092] In the display system 10, the second λ / 4 component 22 is composed of the phase difference film described in item A and is integrated with the first lens portion 16 having a curved surface. The integration of the second λ / 4 component 22 with the first lens portion 16 can be achieved by integrating the aforementioned phase difference film, which is the second λ / 4 component 22, with the first lens portion. The second λ / 4 component (the phase difference film described in item A) 22 may, for example, include any other optical component and is integrated with the first lens portion 16 as an optical laminate having an adhesive layer (e.g., an adhesive layer) on the outermost layer.

[0093] The radius of curvature of the curved surface of the first lens portion 16 is, for example, 20 mm or more, and for example, 25 mm or more, and for example, 30 mm or more, and 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, and for example, 30 mm to 70 mm. Furthermore, in the example shown, the second λ / 4 component 22 is integrated with the concave surface of the first lens portion 16, but it may also be integrated with the convex surface. The method of integrating the second λ / 4 component or optical laminate with the first lens portion is not particularly limited, for example, the same method as the method of integrating the phase difference film described in item A with a component having a curved surface can be used.

[0094] Figure 4 This is a schematic cross-sectional view and an enlarged view of its main parts illustrating an example of the construction of an integral body 100 formed by integrating an optical laminate 70, including a second λ / 4 component (the phase difference film described in item A), with a first lens portion 16. The optical laminate 70 includes a component (so-called a second positive C-plate) 72 disposed on one side of the second λ / 4 component 22, whose refractive index characteristics show a relationship of nz>nx=ny, and a second protective component 74 disposed on the other side. The second λ / 4 component 22, the second positive C-plate 72, and the second protective component 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 side of the second positive C-plate 72 opposite to the side where the second λ / 4 component 22 is disposed. The optical laminate 70 is 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.

[0095] The phase difference Rth (550) in the thickness direction of the second positive C-plate 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 second positive C-plate is, for example, less than 10nm.

[0096] The second positive C-plate can be formed from any suitable material, but it can be composed of a film containing a liquid crystal material fixed in a vertical orientation. The vertically oriented liquid crystal material (liquid crystal compound) can be a liquid crystal monomer or a liquid crystal polymer. As a specific example of such a liquid crystal compound and a method for forming the second positive C-plate, the liquid crystal compound and the method for forming the phase retardation layer described in paragraphs

[0020] to

[0028] of Japanese Patent Application Publication No. 2002-333642 can be cited. In this case, the thickness of the second positive C-plate is preferably 0.5µm to 5µm.

[0097] 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.

[0098] 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.

[0099] 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.

[0100] In the display system 10, the first λ / 4 component 20 may also be composed of the phase retardation film described in item A. In this case, the first λ / 4 component (the phase retardation film described in item A) 20 may also be integrated with the display surface 12a of the display element 12. The display surface of the display element may be planar. As described above, the absolute value of the RS of the phase retardation film described in item A is small, and the change in optical characteristics caused by integration with a component having a curved surface is small. Therefore, by setting the phase retardation film described in item A as the first λ / 4 component and the second λ / 4 component, and integrating them along the display surface of the planar 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 absolute value of the difference between the in-plane phase difference Re (550) of the phase difference film (first λ / 4 component) integrated with the display element and the in-plane phase difference Re (550) of the phase difference film (second λ / 4 component) 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.

[0101] The first λ / 4 component (the phase difference film described in item A) 20 may also include any other suitable optical components, and as an optical laminate having an adhesive layer (e.g., an adhesive layer) on the outermost layer, it may be integrated with the display element 12.

[0102] Figure 5 This is a schematic cross-sectional view illustrating an example of the configuration of an optical laminate 80 including a first λ / 4 component (the phase difference film described in item A) 20. The optical laminate 80 includes a polarizing component 82 disposed on one side of the first λ / 4 component 20, a first positive C-plate 84 disposed sequentially on the other side, and a first protective component 86. The polarizing component 82 is a polarizing component that may be included in the display element 12. The optical laminate 80 also includes a first adhesive layer 88 on the side of the polarizing component 82 opposite to the side where the first λ / 4 component 20 is disposed. The optical laminate 80 can be attached to the front side of the display element via the first adhesive layer 88.

[0103] 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.

[0104] 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.

[0105] 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.

[0106] 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, dyeing can be performed after stretching. Depending on the requirements, the PVA membrane may undergo swelling treatment, crosslinking treatment, cleaning treatment, drying treatment, etc.

[0107] 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.

[0108] 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.

[0109] 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.

[0110] Polarization P (%) = {(Tp-Tc) / (Tp+Tc)} 1 / 2 ×100

[0111] The same descriptions as those for the first positive C-plate, the first protective component, and the first adhesive layer can be applied to each of them.

[0112] C. Phase retardation film components

[0113] According to another aspect of the present invention, an assembly of two phase retardation films is provided, each of which independently has an in-plane phase difference Re(550) of 100 nm to 190 nm and an absolute value of the phase difference change RS of 2.0 or less. The absolute value of the difference between the in-plane phase differences Re(550) of the two phase retardation films included in the above assembly is, for example, 10 nm or less, preferably 7 nm or less, and more preferably 0 nm to 5 nm. Each of the two phase retardation films included in the above assembly is preferably the phase retardation film described in item A.

[0114] like Figure 3As shown, the above-described display system may include a planar first λ / 4 component and a curved second λ / 4 component. In such a display system, by using one of the components of the aforementioned phase retardation film to form the first λ / 4 component and the other to form the second λ / 4 component, even if the other phase retardation film deforms following the curvature of the first lens portion, the difference in in-plane phase difference between the first λ / 4 component and the second λ / 4 component can still be reduced (for example, the absolute value of the difference in Re(550) of the in-plane phase difference is 10 nm or less, preferably 7 nm or less, more preferably 5 nm or less, and even more preferably 0 nm to 3.5 nm), resulting in a display system with excellent visibility.

[0115] D. Phase retardation film

[0116] According to the phase retardation film having the absolute value of RS as described in item A, even when stretched from a planar shape to a curved shape due to integration with a component having a curved surface, the deviation of the in-plane phase difference can still be reduced. Therefore, according to another aspect of the present invention, a phase retardation film sheet is provided, which has a curved surface; and the absolute value of the difference between the in-plane phase difference Re(550) at the central portion of the curved surface and the in-plane phase difference Re(550) at the portion other than the central portion is, for example, 15 nm or less, 10 nm or less, or 6 nm or less. The radius of curvature of the curved surface of the phase retardation film sheet is, for example, 20 mm or more, and for example, 25 mm or more, 30 mm or more, and 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 phase retardation film sheet may be, for example, 20 mm to 80 mm, and may be, for example, 30 mm to 70 mm.

[0117] Example

[0118] 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.

[0119] <Thickness>

[0120] 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.).

[0121] <Phase difference>

[0122] The in-plane phase difference at 23°C was measured using a birefringence distribution meter (manufactured by Photron, product name "KAMAKIRI X stage").

[0123] [Example 1]

[0124] 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.

[0125] [Chemical Formula 1]

[0126]

[0127] [Chemical Formula 2]

[0128]

[0129] Alternatively, an alignment film was coated onto a 0.7 mm thick glass substrate using a spin-coating method with a polyimide solution. After drying at 100°C for 10 minutes, the film was fired at 200°C for 60 minutes to obtain the coating. The obtained coating was then subjected to friction treatment using a commercially available friction device to form an alignment film.

[0130] Next, the obtained polymeric composition was spin-coated onto a substrate (essentially an oriented film) 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 Irradiate with ultraviolet light of high intensity for 30 seconds to obtain a directional curing layer of liquid crystal compound, namely the phase difference film 1 (thickness 3µm).

[0131] The in-plane phase difference Re(550) of the phase retardation film 1 is 140 nm. The Re(450) / Re(550) ratio of the phase retardation film 1 is 0.851, which shows the inverse wavelength dispersion characteristics.

[0132] [Example 2]

[0133] An extended film of a cyclic olefin resin membrane (manufactured by ZEON Corporation, Japan, ZeonorFilm ZD) was used as the chromatic retardation film 2. The thickness of the chromatic retardation film 2 was 22 µm, and the in-plane phase difference Re(550) was 141 nm. The Re(450) / Re(550) ratio of the chromatic retardation film 2 was 1.00, exhibiting flat dispersive wavelength characteristics.

[0134] [Comparative Example 1]

[0135] 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 spirocyclohexane (SPG), 63.77 parts by weight (0.298 mol) of diphenyl carbonate (DPC), and 1.19 × 10⁻² parts by weight (6.78 × 10⁻⁵ mol) of calcium acetate monohydrate as a catalyst were added. After nitrogen purging under reduced pressure, the reactor was heated with a hot medium, and stirring was started when the internal temperature reached 100°C. Forty minutes after the start of heating, the internal temperature was raised to 220°C, and the pressure was reduced while maintaining this temperature. After reaching 220°C, the pressure was reduced to 13.3 kPa over 90 minutes. Phenol vapor generated during the polymerization reaction is introduced into a 100°C reflux cooler to return the small amount of monomer components contained in the phenol vapor to the reactor, while uncondensed phenol vapor is recovered by being introduced into a 45°C condenser. Nitrogen is introduced into the first reactor and temporarily restored to atmospheric pressure before the oligomerized reaction liquid in the first reactor is transferred to the second reactor. Next, the temperature and pressure in the second reactor are increased and decreased, and the internal temperature is brought to 240°C and the pressure to 0.2 kPa over 50 minutes. Polymerization is then carried out until the specified stirring power is reached. At the point where the specified power is reached, nitrogen is introduced into the reactor and the pressure is restored. The resulting polyester carbonate resin is extruded into water and cut into bundles to obtain granules.

[0136] After the obtained polyester carbonate resin (granules) was vacuum dried at 80°C for 5 hours, a strip resin film with a thickness of 130µm was produced using a film forming device equipped with a single screw extruder (manufactured by Toshiba Machine Co., Ltd., cylinder set temperature: 250°C), T-die (width 200mm, set temperature: 250°C), cooling roller (set temperature: 120~130°C) and winding machine.

[0137] The obtained elongated resin film was stretched in the width direction at a stretching temperature of 140℃ and a stretching ratio of 2.7 times, and then wound into a roll. Thus, a phase difference film C1 with a thickness of 47µm, a Re(590) of 140nm, and an Nz coefficient of 1.2 was obtained.

[0138] The phase difference film C1 has a Re(450) / Re(550) ratio of 0.859, exhibiting inverse wavelength dispersion characteristics.

[0139] [Comparative Example 2]

[0140] A strip-shaped resin film with a thickness of 130 µm was stretched in the width direction at a stretching temperature of 137 °C and a stretching ratio of 2.1 times. Except for this, it was the same as in Comparative Example 1 to obtain a retardation film C2 with a thickness of 57 µm, Re(590) of 140 nm, and an Nz coefficient of 1.2.

[0141] The Re(450) / Re(550) of the retardation film C2 was 0.859, showing an inverse wavelength dispersion characteristic.

[0142] <Retardation change value RS>

[0143] The retardation films obtained in the examples and comparative examples were adhered to an acrylic film (Re(550) ≈ 0 nm) via an acrylic adhesive layer (thickness 5 µm) to obtain a laminate. The obtained laminate was cut into a length of 150 mm and a width of 15 mm with the slow axis direction of the retardation film as the length direction to prepare a sample. In addition, the above acrylic film is a film that hardly causes a retardation change due to the application of the following tension.

[0144] A tensiometer (manufactured by MYCARBON, product name "Digital Luggage Scale") was used to apply tension in the length direction of the obtained sample. At the stages of tensions of 0 kg, 0.5 kg, 1 kg, 1.5 kg, and 2 kg, the in-plane retardation (Re(550)) was measured using a retardation measurement device (manufactured by Axometrics, product name: Axo Scan). Using Excel functions, with the tension as the x-axis and Re(550) as the y-axis, the Re(550) values measured at each tension were plotted to form an approximate straight line, and the slope of this approximate straight line was taken as the retardation change value RS.

[0145] <Thickness deviation>

[0146] The retardation films obtained in the examples and comparative examples were cut into a size of 100 mm × 100 mm to prepare measurement specimens. As Figure 6 shown, the thicknesses of a total of 5 points, namely the center of the measurement specimen and 4 points 10 mm away from the center in the up, down, left, and right directions, were measured, and the difference between the maximum value and the minimum value was taken as the thickness deviation.

[0147] <ISC value> <N

[0148] For the retardation films obtained in the examples and comparative examples, the ISC value was measured using an EyeScale-4W manufactured by i-system Co., Ltd. Specifically, according to the specifications of the measurement device, the in-plane unevenness was calculated as the ISC value in the ISC measurement mode of the 3CCD image sensor.

[0149] Figure 7This diagram illustrates the method for measuring ISC values ​​and is a schematic diagram of the configuration of the light source, phase retardation film, screen, and CCD camera, viewed from above. Figure 7 As shown, a light source Ls, a phase retardation film M, and a screen S are arranged in sequence, and the transmitted image projected onto the screen S is measured using a CCD camera C. Furthermore, the phase retardation film M is attached to an alkali-free glass plate (manufactured by Corning, 1737) and is configured such that the glass plate is positioned on the side of the light source Ls for measurement.

[0150] The distance from the light source Ls to the phase retardation film M along the X-axis is set to 10-60 cm. The distance from the light source Ls to the screen S along the X-axis is set to 70-130 cm. The distance from the CCD camera C to the phase retardation film M along the Y-axis is set to 3-30 cm. The distance from the CCD camera C to the screen S along the X-axis is set to 70-130 cm.

[0151] <Fabrication and Evaluation of Integrated Curved Surfaces>

[0152] 1. Fabrication of lenses with phase retardation films

[0153] 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 65mm and a radius of curvature of 75mm 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.

[0154] 2. Phase difference change at the center

[0155] For the lens with phase difference film obtained in 1, the in-plane phase difference Re at the center of the phase difference film was measured (543). a Calculate Re(543) for the portion corresponding to the central portion of the phase difference film before bonding. b With Re (543) a The difference (Re (543)) b -Re (543) a The absolute value of the phase difference caused by the bonding of the curved surface to the center is taken as the phase difference change. In addition, regarding the phase difference change caused by bonding to the curved surface, an absolute value of 6.0 nm or more can be evaluated as "poor (×)" and a value less than 6.0 nm can be evaluated as "good (○)".

[0156] 3. In-plane phase difference is uneven

[0157] Regarding the lens with a phase difference film obtained in step 1, the in-plane phase difference Re(543) is measured over the entire surface of the phase difference film. From the resulting in-plane phase difference distribution, the difference between the in-plane phase difference Re(543) at the center and the portion outside (the exterior) is detected, and its maximum value is taken as the in-plane phase difference non-uniformity. Furthermore, regarding the in-plane phase difference non-uniformity (|Re(543)...) 中心部 -Re (543) 外部 |), we can evaluate 15nm and above as “poor (×)”, 10nm and below as “acceptable (△)”, and below 10nm as “good (○)”.

[0158] Uneven Ellipticity

[0159] Using a Mueller matrix polarimeter (manufactured by Axometrics, product name "Axoscan"), linearly polarized light with a wavelength of 550 nm was incident from the lens side with a phase retardation film at 23°C. The ellipticity of the transmitted light (diffuse light) was measured across the entire surface of the phase retardation film side. The difference between the ellipticity of the detection center and the outer portion (exterior) in the resulting ellipticity distribution was taken as the maximum value as the ellipticity non-uniformity. Furthermore, regarding ellipticity non-uniformity (|ellipticity)... 中心部 - Ellipticity 外部 |), values ​​greater than 0.15 can be rated as “poor (×)”, values ​​greater than 0.1 but less than 0.15 can be rated as “acceptable (△)”, and values ​​less than 0.1 can be rated as “good (○)”.

[0160] 5. Peel test

[0161] The lens with the phase retardation film was placed in an oven at 80°C and 0%RH for 120 hours and then removed. Its appearance was visually inspected to evaluate whether the phase retardation film had peeled off.

[0162] <Fabrication and Evaluation of Planar Integrated Objects>

[0163] 1. Fabrication of glass plates with phase retardation films

[0164] The phase retardation film obtained in the examples and comparative examples was cut into a square with dimensions of 100mm × 100mm, with the slow axis direction and width direction as the side directions. An acrylic adhesive layer (5µm thick) was applied to one side of the square, and the square was then bonded to a flat glass plate (1.1mm thick) via the adhesive layer. This resulted in an integrated product of the phase retardation film and the glass plate, i.e., a glass plate with a phase retardation film.

[0165] 2. Size variation

[0166] The glass plate with the phase retardation film obtained in step 1 was placed in an oven at 85°C and 0%RH for 500 hours. Then, the size of the phase retardation film on the glass plate was measured, and the dimensional change rate before and after heating [(size before heating - size after heating) / size before heating × 100] was calculated as the dimensional change rate in the slow axis direction.

[0167] 3. Phase difference change

[0168] The in-plane phase difference Re(543) of the phase retardation film obtained in step 1 was measured. The glass plate with the phase retardation film was then placed in an oven at 85°C and 0%RH for 500 hours, and the in-plane phase difference Re(543) of the phase retardation film was measured again. The Re(543) of the phase retardation film before heat treatment was calculated. b Compared with heat-treated Re (543) a The difference (Re (543)) b -Re (543) a The absolute value of the phase difference caused by heating is taken as the phase difference change. In addition, regarding the phase difference change caused by heating, those above 4.0nm are evaluated as "poor (×)", those above 3.5nm and below 4.0nm are evaluated as "acceptable (△)", those above 2.0nm and below 3.5nm are evaluated as "good (○)", and those below 2.0nm are evaluated as "excellent (◎)".

[0169] The results are shown in Table 1.

[0170] [Table 1]

[0171]

[0172] If a phase retardation film with a small absolute value of RS is used in an embodiment, the phase difference change and the ellipticity change of the transmitted light caused by bonding with a curved lens are small, and peeling due to heating is less likely to occur. When the phase retardation film is used as an integral part of a curved lens in a display system, it can leverage the optical properties of the target and help improve visibility.

[0173] This invention is not limited to the embodiments described above, and various modifications can be made. For example, it can be replaced with a configuration that is substantially the same as the configuration shown in the above embodiments, a configuration that can perform the same function, or a configuration that can achieve the same purpose.

[0174] Industrial availability

[0175] The manufacturing method of the display system according to the embodiments of the present invention can be used, for example, to manufacture display systems such as VR goggles.

[0176] Explanation of reference numerals in the attached figures

[0177] 1: Phase retardation thin film

[0178] 10: Display System

[0179] 12: Display element

[0180] 14: Reflective polarizing component

[0181] 16: First lens section

[0182] 18: Semi-reflective mirror

[0183] 20: First λ / 4 component

[0184] 22: Second λ / 4 component

[0185] 24: Second lens section

Claims

1. A manufacturing method for a display system that displays images to a user, characterized in that, The display system includes: A display element having a display surface from which light that will display 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 λ / 4 component is disposed in the optical path between the display element and the semi-reflective mirror; The second λ / 4 component is disposed in the optical path between the semi-reflective mirror and the reflective polarizing component. The manufacturing method includes the following steps: A phase difference film with an in-plane phase difference Re(550) of 100nm~190nm and an absolute value of 2.0 or less for the phase difference change value RS is used as the second λ / 4 component and integrated 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 film under tension 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; One of the phase difference films is integrated with the display element as the first λ / 4 component; Another phase difference film is integrated with the first lens portion as the second λ / 4 component.

3. A method for manufacturing a lens portion for use in 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 λ / 4 component is disposed in the optical path between the semi-reflective mirror and the reflective polarizing component. The manufacturing method includes the following steps: A phase difference film with an in-plane phase difference Re(550) of 100nm~190nm and an absolute value of 2.0 or less for the phase difference change value RS is used as the second λ / 4 component and integrated 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 film under tension of 0kg, 0.5kg, 1kg, 1.5kg and 2kg.

4. A phase retardation thin film, characterized in that, The in-plane phase difference Re(550) is 100nm~190nm. The absolute value of the phase difference change value RS is less than 2.

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, The in-plane phase differences Re(450), Re(550), and Re(650) satisfy the following relationships (i) to (iii): (i) 100nm <Re(550)<160nm、 (ii)Re(450) / Re(550)<1.1, (iii) Re(650) / Re(550)>0.

9.

6. The phase retardation thin film as described in claim 4, characterized in that, The dimensional change rate before and after heat treatment at 85℃ for 500 hours is less than 0.02%.

7. The phase retardation thin film as described in claim 4, characterized in that, The absolute value of the difference in in-plane phase difference Re(550) before and after heat treatment at 85℃ for 500 hours is less than 3.5 nm.

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

9. The phase retardation thin film as described in claim 8, characterized in that, The radius of curvature of the surface is 20 mm or more.

10. The phase retardation thin film as claimed in claim 4, characterized in that, After integration with a component having a top-view shape with a radius of 32.5 mm and a curvature radius of 75 mm, the absolute value of the difference between the in-plane phase difference Re(550) at the center and the in-plane phase difference Re(550) at the portion outside the center is less than 10 nm.

11. The phase retardation film as claimed in claim 4, which is used integrated with the first lens unit as a second λ / 4 component in a display system. The display system includes: A display element having a display surface from which light that will display 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; The 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 λ / 4 component is disposed in the optical path between the display element and the semi-reflective mirror; The second λ / 4 component is disposed in the optical path between the semi-reflective mirror and the reflective polarizing component.

12. A phase retardation thin film, characterized in that, It has a curved surface. The absolute value of the difference between the in-plane phase difference Re(550) of the central part of the surface and the in-plane phase difference Re(550) of the part outside the central part is less than 10 nm.

13. An assembly of a phase retardation film, which in a display system is an assembly for constituting a first phase retardation film for a first λ / 4 component and a second phase retardation film for constituting a second λ / 4 component. The display system includes: A display element having a display surface from which light that will display 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 λ / 4 component is disposed in the optical path between the display element and the semi-reflective mirror; The second λ / 4 component is disposed in the optical path between the semi-reflective mirror and the reflective polarizing component. In the display system, the second λ / 4 component is integrated with the first lens unit. The first phase difference film and the second phase difference film are each phase difference films with an in-plane phase difference Re(550) of 100nm to 190nm and an absolute value of phase difference change value RS of 2.0 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 under tensions of 0kg, 0.5kg, 1kg, 1.5kg, and 2kg. The absolute value of the difference between the in-plane phase difference Re(550) of the first phase difference film and the in-plane phase difference Re(550) of the second phase difference film is less than 5 nm.

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