Optical film with surface protective film and method for inspecting optical film

Abstract

Provided is an optical film with a surface protective film, the optical film comprising an optical film and a surface protective film layer disposed on one side of the optical film, the surface protective film layer comprising two or more surface protective films each having a base material and an adhesive layer. In the optical film with the surface protective films, the peeling force P1 of the innermost surface protective film with respect to the optical film and the peeling force P2 of the outermost surface protective film with respect to the adjacent surface protective film satisfy the relationship of the following formula (1): P2 < = 3.5 P1 (1), the innermost surface protective film is a film of the surface protective film layer disposed closest to the optical film, and the outermost surface protective film is a film of the surface protective film layer disposed outermost.

Description

Technical Field

[0001] This invention relates to optical films with surface protective films and methods for inspecting optical films. 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 developed. For example, goggles with displays for virtual reality (VR) have begun to be commercialized. VR goggles magnify the image displayed on the display panel for the observer to see, therefore, the optical films used in VR goggles require more stringent defect management than those used in existing image display devices.

[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] As mentioned above, strict defect management is required for optical films used in VR goggles, thus precise defect inspection using automated optical inspection (AOI) is necessary. Furthermore, it is preferable to protect the surface of the optical film during the period before final assembly. Therefore, the main object of the present invention is to provide an optical film with a surface protective film, which allows for proper defect inspection while protected by the surface protective film.

[0009] Technical solutions for solving technical problems

[0010] [1] According to one aspect of the present invention, an optical film with a surface protective film is provided, comprising an optical film and a surface protective film layer disposed on one side of the optical film, the surface protective film layer comprising two or more surface protective films having a substrate and an adhesive layer, wherein the peel force P1 of the innermost surface protective film relative to the optical film and the peel force P2 of the outermost surface protective film relative to the adjacent surface protective film satisfy the following relationship (1): P2≤3.5×P1 (1), the innermost surface protective film is the film of the surface protective film layer disposed on the side closest to the optical film, and the outermost surface protective film is the film of the surface protective film layer disposed on the outermost side.

[0011] [2] In the optical film with surface protective film described in [1] above, the surface protective film layer is composed of the innermost surface protective film, the middle surface protective film and the outermost surface protective film. The peel force P2 of the outermost surface protective film relative to the middle surface protective film and the peel force P3 of the middle surface protective film relative to the innermost surface protective film satisfy the following relationship (2) and (3): P2≤2.5×P3 (2), P3≤2×P1 (3).

[0012] [3] In the optical film with surface protective film described in [1] or [2] above, the ratio (T1 / T2) of the thickness T1 of the innermost surface protective film to the thickness T2 of the outermost surface protective film is 1.03 or more.

[0013] [4] In any of the above [1] to [3] optical films with surface protective films, the bending strength of the substrate of the innermost surface protective film at 23°C is greater than or equal to the bending strength of the substrate of the outermost surface protective film at 23°C.

[0014] [5] In any of the above [1] to [4] optical films with surface protective films, the surface of the surface protective film layer of the optical film is an anti-reflective layer.

[0015] [6] In any of the above [1] to [5] optical films with surface protective films, the water contact angle of the surface protective film layer side surface of the optical film is 80° or more.

[0016] [7] According to another aspect of the present invention, an inspection method for an optical film is provided, comprising the following steps: peeling off the outermost surface protective film from an optical film with a surface protective film as described in any one of technical solutions 1 to 6 to obtain the optical film in a state protected at least by the innermost surface protective film; and using the optical film in a state protected at least by the innermost surface protective film for defect inspection.

[0017] Invention Effects

[0018] According to an embodiment of the present invention, a surface protective film layer comprising two or more surface protective films is disposed on one side of the optical film, and the peel force of the innermost surface protective film relative to the optical film and the peel force of the outermost surface protective film relative to the adjacent surface protective film are adjusted in a manner that satisfies a predetermined relationship. Therefore, it is possible to suppress the simultaneous peeling of the innermost surface protective film when peeling off the outermost surface protective film.

[0019] Based on such an optical film with a surface protective film, by peeling off the outermost surface protective film, an optical film can be appropriately obtained that is protected by a surface protective film located inside it, preventing the adhesion of scratches, dirt, etc. This optical film, protected by a clean surface protective film, can still suppress false detection of defects caused by the surface protective film even when used directly for defect inspection. Attached Figure Description

[0020] Figure 1 This is a schematic diagram illustrating a schematic configuration of an example of a display system with an optical film having a surface protective film, to which embodiments of the present invention can be applied.

[0021] Figure 2 This is a schematic cross-sectional view illustrating the general configuration of an optical film with a surface protective film according to one embodiment of the present invention.

[0022] Figure 3 This is a schematic cross-sectional view showing the general configuration of an optical film with a surface protective film according to one embodiment of the present invention.

[0023] Figure 4 This is a schematic cross-sectional view illustrating an example of the structure of an optical film with a surface protective film applicable to embodiments of the present invention.

[0024] Figure 5 This is a schematic cross-sectional view illustrating an example of the structure of an optical film with a surface protective film applicable to embodiments of the present invention.

[0025] Figure 6A This is a schematic top view illustrating the method for measuring the peel strength of a surface protective film.

[0026] Figure 6B This is a schematic side view illustrating the method for measuring the peel strength of a surface protective film.

[0027] Figure 7A It is a schematic top view illustrating the peeling test method.

[0028] Figure 7B It is a schematic top view illustrating the peeling test method. Detailed Implementation

[0029] 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 the purpose of clearer illustration, the width, thickness, shape, etc., of various parts may be schematically shown compared to the embodiments, but these are only examples and do not limit the interpretation of the present invention.

[0030] (Definitions of terms and symbols)

[0031] The terms and symbols used in this specification are defined as follows.

[0032] (1) Refractive index (nx, ny, nz)

[0033] “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.

[0034] (2) In-plane phase difference (Re)

[0035] “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).

[0036] (3) Phase difference in the thickness direction (Rth)

[0037] “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).

[0038] (4) Nz coefficient

[0039] The Nz coefficient can be obtained by Nz=Rth / Re.

[0040] (5) Angle

[0041] When referring to angles in this specification, unless otherwise specified, the angle includes both clockwise (+) and counterclockwise (-) directions relative to a reference direction. Therefore, for example, "45°" means ±45°. Furthermore, in this specification, "approximately parallel" includes a range of 0° ±10°, preferably within the range of 0° ±5°. "Approximately orthogonal" includes a range of 90° ±10°, preferably within the range of 90° ±5°.

[0042] A. Display System

[0043] Figure 1 This is a schematic diagram illustrating a schematic configuration of an example of a display system with an optical film having a surface protective film, to which embodiments of the present invention can be applied. Figure 1The diagram schematically illustrates the arrangement and shape of the various components of the display system 2. The display system 2 includes: a display element 12, a reflective portion 14 including a reflective polarizing component, a first lens portion 16, a semi-reflective mirror 18, a first phase difference component 20, a second phase difference component 22, and a second lens portion 24. The reflective portion 14 is disposed on the display surface 12a side, i.e., in front of the display element 12, 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 portion 14, and the semi-reflective mirror 18 is disposed between the display element 12 and the first lens portion 16. The first phase difference component 20 is disposed in the optical path between the display element 12 and the semi-reflective mirror 18, and the second phase difference component 22 is disposed in the optical path between the semi-reflective mirror 18 and the reflective portion 14.

[0044] 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 (represented by a polarizing film) that may be included in the display element 12 and is then emitted as first linearly polarized light.

[0045] The first phase difference component 20 includes a first λ / 4 component, which converts the first linearly polarized light incident on the first phase difference component 20 into first circularly polarized light. If the first phase difference component does not include any components other than the first λ / 4 component, the first phase difference component can be equivalent to the first λ / 4 component. The first phase difference component 20 can also be integrally disposed with the display element 12.

[0046] The semi-reflective mirror 18 allows light emitted from the display element 12 to pass through and causes light reflected by the reflective portion 14 to be reflected towards the reflective portion 14. The semi-reflective mirror 18 is integrally provided with the first lens portion 16.

[0047] The second phase difference component 22 includes a second λ / 4 component that allows light reflected by the reflector 14 and the semi-reflector 18 to pass through the reflector 14. If 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 portion 16.

[0048] 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 is reflected towards the half-reflector 18 without passing through the reflective polarizing component included in the reflective section 14. At this time, the polarization direction of the second linearly polarized light incident on the reflective polarizing component included in the reflective section 14 is the same as the reflection axis of the reflective polarizing component. Therefore, the second linearly polarized light incident on the reflective section is reflected by the reflective polarizing component.

[0049] The second linearly polarized light reflected by the reflector 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-reflector 18 after passing through the first lens 16. The second circularly polarized light reflected by the half-reflector 18 passes through the first lens 16 and is converted into third linearly polarized light by the second λ / 4 component included in the second phase difference component 22. The third linearly polarized light passes through the reflective polarizing component. At this time, the polarization direction of the third linearly polarized light incident on the reflective polarizing component included in the reflector 14 is the same as the transmission axis of the reflective polarizing component. Therefore, the third linearly polarized light incident on the reflector 14 passes through the reflective polarizing component.

[0050] Light that has passed through the reflector 14 passes through the second lens 24 and enters the user's eye 26.

[0051] Furthermore, the display system 2 may also include an absorptive polarizing element (represented as an absorptive polarizing film) in front of the reflective polarizing element in the reflective section 14. The reflection axis of the reflective polarizing element and the absorption axis of the absorptive polarizing element may be configured to be substantially parallel to each other, and the transmission axis of the reflective polarizing element and the transmission axis of the absorptive polarizing element may be configured to be substantially parallel to each other. Thus, the third linearly polarized light that has passed through the reflective polarizing element can directly pass through the absorptive polarizing element.

[0052] For example, the absorption axis of the polarizing component included in the display element 12 and the reflection axis of the reflective polarizing component included in the reflective portion 14 can be configured to be substantially parallel to each other, or substantially 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 included in the first phase difference component 20 is, for example, 40° to 50°, 42° to 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 included in the second phase difference 22 is, for example, 40° to 50°, 42° to 48°, or approximately 45°.

[0053] 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. Preferably, the first λ / 4 component exhibits inverse dispersion wavelength 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 is, for example, 0.75 or more and less than 1, or 0.8 or more and less than 0.95.

[0054] 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. Preferably, the second λ / 4 component exhibits inverse dispersion wavelength characteristics where the phase difference value increases with the wavelength of the measurement 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.

[0055] As described above, in display system 2, the light emanating from the display surface 12a of display element 12 and projecting a displayed image forward is magnified by the first lens section and the second lens section, making it visible to an observer. For optical films used in such display systems, more stringent defect management is required than in existing image display devices. For example, the permissible defect size for optical films used in the aforementioned display system is, for example, 80µm or less, 50µm or less, or 30µm or less, and can be, for example, 5µm or more, or 10µm or more.

[0056] B. Optical film with surface protective film

[0057] The optical film with a surface protective film according to an embodiment of the present invention comprises an optical film and a surface protective film layer disposed on one side of the optical film. The surface protective film layer comprises two or more surface protective films (hereinafter sometimes referred to as "PF") having a substrate and an adhesive layer. Typically, the peel force of the innermost PF (hereinafter sometimes referred to as "innermost PF") disposed on the optical film is peel force P1, and the peel force of the outermost PF (hereinafter sometimes referred to as "outermost PF") disposed on the adjacent PF is peel force P2, and the two satisfy the relationship of the following formula (1). P1 and P2 preferably satisfy the relationship of the following formula (1a) or (1b). In addition, P1 and P2 may satisfy the relationship of the following formula (1c) or (1d). When P1 and P2 satisfy such a relationship, the simultaneous peeling of the innermost PF when peeling the outermost PF can be appropriately suppressed.

[0058] P2≤3.5×P1 (1)

[0059] P2≤3×P1 (1a)

[0060] P2≤2.5×P1 (1b)

[0061] P2≥0.9×P1 (1c)

[0062] P2≥1×P1 (1d)

[0063] Figure 2This is a schematic cross-sectional view showing the general configuration of an optical film with a surface protective film according to one embodiment of the present invention. The optical film 100A with a surface protective film includes an optical film 50 and a surface protective film layer 60 disposed on one side of the optical film 50. The surface protective film layer 60 is composed of an innermost layer PF62 disposed on the innermost side and an outermost layer PF64 disposed on the outermost side. The innermost layer PF62 and the outermost layer PF64 each have substrates 62a and 64a and adhesive layers 62b and 64b, respectively. In the optical film 100A with a surface protective film, the innermost layer PF62 is adjacent to the outermost layer PF64, and the peel force of the outermost layer PF64 relative to the innermost layer PF62 is a peel force P2. Furthermore, the peel force of the innermost layer PF62 relative to the optical film 50 is a peel force P1.

[0064] Figure 3 This is a schematic cross-sectional view showing the general configuration of an optical film with a surface protective film according to another embodiment of the present invention. The optical film 100B with a surface protective film includes an optical film 50 and a surface protective film layer 60 disposed on one side of the optical film 50. The surface protective film layer 60 is composed of an innermost layer PF62 disposed on the innermost side, an outermost layer PF64 disposed on the outermost side, and an intermediate PF66 disposed therebetween. The intermediate PF66 has a substrate 66a and an adhesive layer 66b. Typically, the peel force P1 of the innermost layer PF62 relative to the optical film 50 and the peel force P2 of the outermost layer PF64 relative to the intermediate PF66 satisfy the relationship of the above formula (1). P1 and P2 preferably satisfy the relationship of the above formula (1a) or (1b). In addition, P1 and P2 may satisfy the relationship of the above formula (1c) or (1d). Furthermore, the peeling forces P3 and P2 of the middle PF66 relative to the innermost PF62 preferably satisfy the relationship of equation (2) below, and more preferably satisfy the relationship of equation (2a) and / or (2b) below. P3 and P1 preferably satisfy the relationship of equation (3) below, and more effectively satisfy the relationship of equation (3a) and / or (3b) below. When P1 to P3 satisfy such a relationship, not only can the simultaneous peeling of the innermost PF and / or the middle PF be appropriately suppressed when peeling the outermost PF, but the simultaneous peeling of the innermost PF can also be appropriately suppressed when peeling the middle PF.

[0065] P2≤2.5×P3 (2)

[0066] P2≤2.3×P3 (2a)

[0067] P2≥2×P3 (2b)

[0068] P3≤2×P1 (3)

[0069] P3≤1.5×P1 (3a)

[0070] P3≥0.9×P1 (3b)

[0071] The peel force P1 of the innermost PF layer relative to the optical film is, for example, less than 0.06 N / 25 mm, or less than 0.055 N / 25 mm or less. The peel force P1 is, for example, greater than 0.02 N / 25 mm, or greater than 0.025 N / 25 mm or greater than 0.03 N / 25 mm.

[0072] The peel force P2 of the outermost PF relative to the adjacent PF can be set to satisfy the above formula (1), preferably, it can be set to satisfy at least one of (1a) to (1d). The peel force P2 is, for example, 0.21 N / 25 mm or less, or 0.18 N / 25 mm or less, or 0.15 N / 25 mm or less. The peel force P2 is, for example, 0.018 N / 25 mm or more, or 0.02 N / 25 mm or more, or 0.022 N / 25 mm or more.

[0073] The peel force P3 of the middle PF relative to the innermost PF can be set to satisfy equation (2) and / or (3) above, preferably to satisfy (2a), (2b), (3a) and / or (3b). The peel force P3 is, for example, 0.12 N / 25 mm or less, or 0.11 N / 25 mm or less, or 0.09 N / 25 mm or less. The peel force P3 is, for example, 0.007 N / 25 mm or more, or 0.008 N / 25 mm or more, or 0.018 N / 25 mm or more.

[0074] The peel forces P1~P3 mentioned above were measured at 23℃ and 50%RH, with a peel angle of 180° and a peel speed of 300mm / min.

[0075] [Surface protective film]

[0076] The surface protective film layer contains two or more protective powders (PFs). The number of PFs contained in the surface protective film layer can be selected according to the purpose, preferably 2 or 3. For example, in... Figure 2 In the illustrated embodiment, the surface protective film layer 60 is composed of an innermost PF62 and an outermost PF64, containing two PFs. For example, in... Figure 3 In the illustrated embodiment, the surface protective film layer 60 comprises an innermost PF62, a middle PF66, and an outermost PF64, containing three PFs. Each PF has a substrate and an adhesive layer disposed on one side thereon, through which it can be adhered to adjacent components. Furthermore, the PFs are engineering components temporarily attached to the optical film and are peeled off during the use of the optical film.

[0077] The haze of the protective film (PF) included in the surface protective film layer is, for example, 10% or less, preferably 5% or less, more preferably 4% or less, more preferably 3% or less, and typically 0.05% or more. It is preferable that the PF disposed inside the outermost PF layer (e.g., the innermost PF layer, the intermediate PF layer) has low haze, for example, 5% or less. When the haze of the PF disposed inside the outermost PF layer is low, the optical film can be used for precise defect inspection while protected by this PF.

[0078] The total light transmittance of the protective film (PF) layer contained therein is, for example, 80% or more, preferably 85% or more, more preferably 88% or more, and more preferably 90% or more. It is preferable that the PF layer disposed inside the outermost PF layer (e.g., the innermost PF layer, the intermediate PF layer) has a high total light transmittance, for example, 85% or more. When the total light transmittance of the PF layer disposed inside the outermost PF layer is high, the optical film can be used for precision defect inspection while protected by this PF layer.

[0079] The thickness of the PF contained in the surface protective film layer is, for example, 15µm to 250µm, preferably 30µm to 150µm, and more preferably 40µm to 100µm.

[0080] In one embodiment, the ratio (T1 / T2) of the thickness T1 of the innermost PF layer to the thickness T2 of the outermost PF layer can be 1.03 or more, for example, 1.03 to 1.2 or 1.2 to 1.5. If the ratio (T1 / T2) is within the above range, the simultaneous peeling of the innermost PF layer during the peeling of the outermost PF layer can be appropriately suppressed.

[0081] As the substrate constituting PF, any suitable resin film can be selected. Specific examples of materials that are the main components of this resin film include: cyclic olefin (COP) based resins such as polynorbornene, polyester based resins such as polyethylene terephthalate (PET), cellulose based resins such as cellulose triacetate (TAC), polycarbonate (PC) based resins, (meth)acrylic resins, polyvinyl alcohol based resins, polyamide based resins, polyimide based resins, polyethersulfone based resins, polysulfone based resins, polystyrene based resins, polyolefin based resins, and acetate based resins, etc. Additionally, thermosetting resins or UV-curing resins such as (meth)acrylic resins, polyurethane resins, (meth)acrylic polyurethane resins, epoxy resins, and silicone resins can also be used. Furthermore, "(meth)acrylic resin" refers to acrylic resins and / or methacrylic resins. Other examples include glassy polymers such as siloxane polymers. Additionally, the polymer film described in Japanese Patent Application Publication No. 2001-343529 (WO01 / 37007) can also be used. As the material for this membrane, for example, resin compositions containing thermoplastic resins having substituted or unsubstituted imide groups on the side chains, and thermoplastic resins having substituted or unsubstituted phenyl and nitrile groups on the side chains can be used. Examples include resin compositions having alternating copolymers of isobutylene and N-methylmaleimide and acrylonitrile-styrene copolymers. The polymer membrane can be an extruded product of the resin composition described above. The resin membrane material can be used alone or in combination.

[0082] Preferably, the substrate comprises at least one transparent resin selected from the group consisting of COP-based, PET-based, TAC-based, PC-based, and (meth)acrylic resins. More preferably, it comprises at least one transparent resin selected from the group consisting of COP-based, PET-based, PC-based, and (meth)acrylic resins. Even more preferably, it comprises at least one transparent resin selected from the group consisting of COP-based, PET-based, and PC-based resins. When the substrate comprises the aforementioned transparent resin, erroneous detections caused by PF (Polyester Polymer) can be more consistently reduced during defect inspection.

[0083] The aforementioned substrate may also contain antioxidants, ultraviolet absorbers, light stabilizers, nucleating agents, fillers, pigments, surfactants, antistatic agents, etc. An easy-adhesion layer, an easy-slip layer, an anti-adhesion layer, an antistatic layer, an anti-reflective layer, an anti-oligomery layer, etc., may also be provided on the surface of the substrate (the surface opposite to the adhesive layer).

[0084] The bending strength of the aforementioned substrate at 23°C is, for example, 40 MPa to 200 MPa, preferably 50 MPa to 180 MPa, and more preferably 60 MPa to 150 MPa. The bending strength can be determined, for example, by following the method of ISO 178 / JIS K7171.

[0085] The ratio (E1 / E2) of the bending strength E1 of the substrate constituting the innermost PF to the bending strength E2 of the substrate constituting the outermost PF is, for example, 1 or more, preferably 1.1 to 1.4, and may be, for example, 1.1 to 1.2 or 1.2 to 1.4. The ratio (E1 / E3) of the bending strength E1 of the substrate constituting the innermost PF to the bending strength E3 of the substrate constituting the intermediate PF is, for example, 1 or more, preferably 1 to 1.17, and may be, for example, 1 to 1.05, 1.05 to 1.09 or 1.09 to 1.17. The ratio (E3 / E2) of the bending strength E3 of the substrate constituting the intermediate PF to the bending strength E2 of the substrate constituting the outermost PF may be 1 or more, preferably 1.1 to 1.4, and may be, for example, 1.1 to 1.2 or 1.2 to 1.4. When the substrate of the peeled PF has more than the remaining substrate flexibility of the PF, simultaneous peeling can be appropriately suppressed.

[0086] The thickness of the aforementioned substrate is typically 5µm or more, preferably 20µm or more, and typically 100µm or less, preferably 80µm or less.

[0087] The adhesive layer constituting the PF can be made of any suitable adhesive. The adhesive constituting the adhesive layer typically contains at least one adhesive selected from the group consisting of (meth)acrylic adhesives, polyurethane adhesives, and silicone adhesives. More preferably, the adhesive layer contains a (meth)acrylic adhesive.

[0088] (Meth)acrylic adhesives contain polymers with monomers primarily composed of alkyl (meth)acrylates (hereinafter referred to as (meth)acrylic polymers). In other words, (meth)acrylic polymers contain structural units derived from alkyl (meth)acrylates. The percentage of structural units derived from alkyl (meth)acrylates in the (meth)acrylic polymer is typically 50% by weight or more, preferably 80% by weight or more, more preferably 93% by weight or more, and for example, 100% by weight or less, preferably 98% by weight or less.

[0089] Alkyl methacrylates may have alkyl groups that are either straight-chain or branched. The alkyl group has, for example, 1 or more but less than 18 carbon atoms. Examples of alkyl groups include methyl, ethyl, butyl, 2-ethylhexyl, decyl, isodecyl, and octadecyl. Alkyl methacrylates may be used alone or in combination. The average number of carbon atoms in the alkyl group is preferably 3 to 10.

[0090] (Meth)acrylate polymers may contain structural units derived from alkyl (meth)acrylate esters, as well as structural units derived from comonomers that can polymerize with alkyl (meth)acrylate esters. Examples of comonomers include carboxyl-containing monomers and hydroxyl-containing monomers. Comonomers can be used alone or in combination.

[0091] Carboxyl-containing monomers are compounds whose structures contain a carboxyl group and polymerizable unsaturated double bonds such as (meth)acryloyl groups and vinyl groups. Examples of carboxyl-containing monomers include (meth)acrylic acid, carboxyethyl (meth)acrylate, maleic acid, fumaric acid, and crotonic acid; preferably, (meth)acrylic acid is also an example. When a (meth)acrylic acid polymer contains structural units derived from a carboxyl-containing monomer, the adhesive properties of the adhesive layer can be improved. When a (meth)acrylic acid polymer contains structural units derived from a carboxyl-containing monomer, the content of the structural units derived from the carboxyl-containing monomer is preferably 0.01% by weight or more and 10% by weight or less.

[0092] Hydroxyl-containing monomers are compounds whose structures contain a hydrocarbon group and polymerizable unsaturated double bonds such as (meth)acryloyl or vinyl groups. Examples of hydroxyl-containing monomers include: 2-hydroethyl (meth)acrylate, 3-hydropropyl (meth)acrylate, 8-hydrooctyl (meth)acrylate, 12-hydrolaurate (meth)acrylate, and (4-hydromethylcyclohexyl)-methacrylate. Examples also include 2-hydroethyl (meth)acrylate and 4-hydrobutyl (meth)acrylate, with 2-hydroethyl (meth)acrylate being preferred. When a methacrylic polymer contains structural units derived from hydroxyl-containing monomers, the durability of the adhesive layer can be improved. When a methacrylic polymer contains structural units derived from hydroxyl-containing monomers, the percentage of these structural units is preferably 0.01% by weight or more and 10% by weight or less.

[0093] The weight average molecular weight (Mw) of the (meth)acrylic polymer is, for example, 100,000 to 2,000,000, preferably 200,000 to 1,000,000.

[0094] In addition, (meth)acrylic adhesives may contain crosslinking agents. Representative examples of crosslinking agents include organic crosslinking agents and multifunctional metal chelates. Organic crosslinking agents include, for example, isocyanate-based crosslinking agents, peroxide-based crosslinking agents, epoxy-based crosslinking agents, and imine-based crosslinking agents, with isocyanate-based crosslinking agents being preferred. When the adhesive contains a crosslinking agent, the crosslinking agent content is typically 0.01 parts by weight or more and 15 parts by weight or less per 100 parts by weight of the (meth)acrylic polymer.

[0095] The aforementioned adhesives (meth)acrylic adhesives, polyurethane adhesives, and silicone adhesives) may also contain various additives in appropriate proportions as needed. By adjusting the composition of the base polymer (e.g., the type and proportion of monomers, the type and proportion of crosslinking agents), the molecular weight of the base polymer, and the type or proportion of additives, an adhesive layer with desired adhesion to the adherends can be obtained.

[0096] Examples of the additives include polymerization initiators, solvents, polymerization catalysts, crosslinking catalysts, silane coupling agents, tackifiers, plasticizers, softeners, anti-aging agents, fillers, colorants (pigments, dyes, etc.), light stabilizers, ultraviolet absorbers, antioxidants, surfactants, antistatic agents, chain transfer agents, etc.

[0097] The thickness of the adhesive layer is, for example, 10 µm or more, preferably 12 µm or more, and for example, 40 µm or less, preferably 30 µm or less, more preferably 25 µm or less.

[0098] The adhesive layer can be formed on the surface of the substrate by direct printing or by transfer printing. In the case of direct printing, the adhesive is directly coated on the surface of the substrate to form the adhesive layer. In the case of transfer printing, after the adhesive is coated on the surface of the release liner to form the adhesive layer, the substrate is attached to the adhesive layer. In particular, when the substrate contains an amorphous resin having a low glass transition temperature Tg (for example, 150°C or lower), the adhesive layer is preferably formed by a transfer printing process. In the case of the transfer printing process, the high temperature during drying required for forming the adhesive layer can be suppressed from affecting the substrate.

[0099] [Optical film]

[0100] The optical film can have any appropriate structure according to the purpose, use, etc. The optical film can have a single-layer structure or can be a laminate having a multilayer structure. For example, the optical film can be a laminate having an antireflection layer as one of its outermost layers. PF has difficulty in exerting sufficient adhesion to a layer having a small surface free energy such as an antireflection layer, etc. As a result, there are cases where P1 cannot be sufficiently increased (for example, the case where P1 < P2). In such a case, according to an embodiment of the present invention, since the peeling force between the outer PF and the inner PF is adjusted to a specified relationship, it is possible to appropriately suppress the simultaneous peeling of the inner PF when the outer PF is peeled.

[0101] In one embodiment, the water contact angle of the side surface of the surface protective film layer of the optical film is, for example, 80° or more, and can also be 90° or more or 100° or more. The water contact angle can be, for example, 150° or less, and can also be, for example, 140° or less. When the wettability of the side surface of the surface protective film layer of the optical film is low, the effects of the present invention can be more appropriately obtained.

[0102] Figure 4This is a schematic cross-sectional view illustrating an example of the structure of an optical film applicable to embodiments of the present invention. The optical film 50a sequentially includes an adhesive layer 31, a polarizing component 10, a first phase retardation component 20, and a first protective component 41. The polarizing component 10, the first phase retardation component 20, and the first protective component 41 are laminated via adhesive layers 33 and 34. The adhesive layers 33 and 34 are typically adhesive layers or bonding agent layers, preferably bonding agent layers. The thickness of the adhesive layers 33 and 34 is, for example, 0.05µm to 30µm. The surface of the adhesive layer 31 is protected by a peel-off substrate 36 during the period before use. For the optical film 50a, a surface protective film layer is disposed on the side surface of the first protective component 41.

[0103] Optical film 50a can be appropriately used for Figure 1 In the illustrated display system 2, specifically, the polarizing component 10 in the optical film 50a is a polarizing component that can be included in the display element 12. By peeling off the substrate 36 from the optical film 50a and bonding it to the constituent components of the display element 12 via the exposed adhesive layer 31, a display system in which the first phase difference component 20 and the display element 12 are integrated can be manufactured.

[0104] Figure 4 In the example shown, the first phase difference component 20, in addition to the first λ / 4 component 20a, also includes a component (so-called positive C-plate) 20b whose refractive index characteristics can represent the relationship nz>nx=ny. The first phase difference component 20 has a laminated structure of the first λ / 4 component 20a and the first positive C-plate 20b. Alternatively, unlike the illustrated example, the first positive C-plate 20b may be located further from the polarizing component 10 than the first λ / 4 component 20a; or the first positive C-plate 20b may be omitted. The first λ / 4 component 20a and the first positive C-plate 20b are laminated, for example, via an adhesive layer (not shown). Furthermore, the angle formed by the absorption axis of the polarizing component 10 and the slow axis of the first λ / 4 component 20a is preferably 40° to 50°, more preferably 42° to 48°, for example, approximately 45°.

[0105] <Polarization component>

[0106] The polarizing film component 10 is typically an absorptive polarizing component comprising a resin film (sometimes called an absorptive polarizing film) containing a dichroic substance, and may further include a protective layer on one or both sides as needed. The protective layer is typically bonded to the absorptive polarizing film via any suitable adhesive layer. An example of an adhesive forming the adhesive layer is a UV-curable adhesive.

[0107] The orthogonal transmittance (Tc) of the polarizing element (absorption-type 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 polarizing element (absorption-type polarizing film) is, for example, 41.0% to 45.0%, preferably 42.0% or more. The polarization degree (P) of the polarizing element (absorption-type polarizing film) is, for example, 99.0% to 99.997%, preferably 99.9% or more.

[0108] The aforementioned orthogonal transmittance, monomer 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 monomer 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 Y values ​​measured using a 2-degree field of view (C light source) according to JIS Z8701 and corrected for visual sensitivity.

[0109] Polarization P (%) = {(Tp-Tc) / (Tp+Tc)} 1 / 2 ×100

[0110] The thickness of the absorptive polarizing film can 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.

[0111] 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.

[0112] When made from 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, and stretching treatments. Among these, an absorptive polarizing film obtained by dyeing a PVA film with iodine and then uniaxially stretching it is preferred.

[0113] The dyeing using iodine described above 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, washing treatment, drying treatment, etc.

[0114] 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, it is preferable to form a polyvinyl alcohol-based resin layer containing a halide and a polyvinyl alcohol-based resin on one side of the resin substrate. Stretching typically includes immersing the laminate in an aqueous boric acid solution. If necessary, stretching may also include air stretching the laminate at a high temperature (e.g., above 95°C) before stretching in the aqueous boric acid solution. Furthermore, in this embodiment, it is preferable to use a drying shrinkage treatment on the laminate, 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 air-assisted stretching, the crystallinity of PVA can be improved even when PVA is coated on a thermoplastic resin, achieving high optical properties. In addition, 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 dyeing and underwater stretching treatments 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 substrate / absorbent polarizing film laminate can be used directly (i.e., the resin substrate can be used as a protective layer for the absorbent polarizing film), or it can be used by laminating any suitable protective layer that meets the purpose on the release surface after peeling the resin substrate from the resin substrate / absorbent polarizing film laminate, or on the surface opposite to the release surface. Detailed descriptions of the manufacturing method of the absorbent 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.

[0115] The protective layer is formed of a resin film made of any suitable resin that can be used as the protective layer of an absorptive polarizing film. Specific examples of the resin that is the main component of the resin film include: cellulose resins such as triacetyl cellulose (TAC), polyester resins, polyvinyl alcohol resins, polycarbonate resins, polyamide resins, polyimide resins, polyethersulfone resins, polysulfone resins, polystyrene resins, cycloolefin resins such as polynorbornene, polyolefin resins, (meth)acrylic resins, acetate resins, etc.

[0116] The thickness of the protective layer is typically 100 µm or less, for example, 5 µm to 80 µm, preferably 10 µm to 50 µm, and more preferably 15 µm to 35 µm.

[0117] <First λ / 4 component>

[0118] The in-plane retardation Re(550) and the dispersion wavelength characteristics of the first λ / 4 component 20a are as described in item A.

[0119] The first λ / 4 component preferably has a refractive index characteristic showing the relationship 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, within the range where the effects of the present invention are not lost, there may be a case where ny < nz. The Nz coefficient of the first λ / 4 component is preferably 0.9 to 3, more preferably 0.9 to 2.5, still more preferably 0.9 to 1.5, and most preferably 0.9 to 1.3.

[0120] The first λ / 4 component is formed of any suitable material that can satisfy the above characteristics. The first λ / 4 component can be, for example, a stretched film of a resin film or an alignment cured layer of a liquid crystal compound.

[0121] Examples of the resin contained in the above resin film 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, acrylic resins, etc. These resins can be used alone or in combination. Examples of the combination method include blending and copolymerization. When the first λ / 4 component exhibits inverse dispersion wavelength characteristics, a resin film containing a polycarbonate resin or a polyester carbonate resin (hereinafter sometimes simply referred to as a polycarbonate resin) can be appropriately used. <00,00270>The aforementioned polycarbonate resin can be any suitable polycarbonate resin. 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 diols. 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; 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, as needed, comprise structural units derived from other dihydroxy compounds. Furthermore, detailed descriptions of the polycarbonate resin suitable for use in the first λ / 4 component and the method for forming the first λ / 4 component are described, for example, in Japanese Patent Application Publication Nos. 2014-10291, 2014-26266, 2015-212816, 2015-212817, and 2015-212818, and these descriptions are incorporated herein by reference.

[0123] The thickness of the first λ / 4 component, which is formed by extending the resin film, is, for example, 10µm to 100µm, preferably 10µm to 70µm, and more preferably 20µm to 60µm.

[0124] 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. Taking the first λ / 4 component as an example, it is typically oriented (plane-oriented) with rod-shaped liquid crystal compounds arranged along the slow axis direction of the first λ / 4 component. Examples of rod-shaped liquid crystal compounds include liquid crystal polymers and liquid crystal monomers. Preferably, the liquid crystal compound is polymerizable. If the liquid crystal compound is polymerizable, it can be polymerized after orientation, thereby fixing the orientation state of the liquid crystal compound.

[0125] The aforementioned liquid crystal compound orientation-cured layer (liquid crystal orientation-cured layer) can be formed by: performing an orientation treatment on the surface of a specified substrate, coating the surface with a coating liquid containing the liquid crystal compound, orienting the liquid crystal compound in the direction corresponding to the orientation treatment, and fixing the orientation state. The orientation treatment can be any suitable orientation treatment. Specific examples include mechanical orientation treatment, physical orientation treatment, and chemical orientation treatment. 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.

[0126] The orientation of liquid crystal compounds can be performed at a temperature that represents a liquid crystal phase, depending on the type of liquid crystal compound. Through this temperature treatment, the liquid crystal compound is placed in a liquid crystal state and oriented according to the orientation treatment direction on the substrate surface.

[0127] In one embodiment, the orientation state is fixed by cooling the liquid crystal compound that is oriented as described above. When 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 that is oriented as described above.

[0128] The aforementioned liquid crystal compound can be made using any suitable liquid crystal polymer and / or liquid crystal monomer. The liquid crystal polymer and liquid crystal monomer can 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.

[0129] The thickness of the first λ / 4 component, which is composed of a liquid crystal orientation curing layer, is, for example, 1µm to 10µm, preferably 1µm to 8µm, more preferably 1µm to 6µm, and even more preferably 1µm to 4µm.

[0130] <First Positive C Board>

[0131] The phase difference Rth (550) in the thickness direction of the first positive C-plate 20b is preferably -20nm to -200nm, more preferably -30nm to -180nm, 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 first positive C-plate is, for example, less than 10nm.

[0132] The first positive C-plate can be formed from any suitable material. Preferably, the first positive C-plate is 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. Specific examples of the liquid crystal compound and the method for forming the positive C-plate can be found in paragraphs

[0020] to

[0028] of Japanese Patent Application Publication No. 2002-333642, which describes the liquid crystal compound and the method for forming the phase retardation layer. In this case, the thickness of the first positive C-plate is preferably 0.5µm to 5µm.

[0133] <First Protective Component>

[0134] The first protective component 41 typically includes a substrate. The substrate can be any suitable film composition. Examples of materials that form the main component of the film constituting the substrate include 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, polyolefin resins, (meth)acrylic acid resins, acetate resins, and other resins. The thickness of the substrate is preferably 5µm to 80µm, more preferably 10µm to 40µm, and more preferably 15µm to 35µm.

[0135] The first protective component preferably has a substrate and a surface treatment layer formed on the substrate. The first protective component with the surface treatment layer can be configured such that the surface treatment layer is located on the front side. Specifically, the surface treatment layer can be located on the outermost surface of the optical film 50a. The surface treatment layer can have any suitable function. Examples of surface treatment layers include, for example, a hard coating, an anti-reflective layer, an anti-stick layer, and an anti-glare layer. The first protective component may also have two or more surface treatment layers.

[0136] An anti-reflective layer is provided to prevent reflection of external light, etc. Examples of anti-reflective layers include fluoropolymer layers, resin layers containing nanoparticles (typically hollow nanoparticles, such as hollow silica nanoparticles), or anti-reflective layers with nanostructures (such as moth-eye structures). The thickness of the anti-reflective layer is preferably 0.05µm to 1µm. Methods for forming the aforementioned resin layers include, for example, the sol-gel method, the thermosetting method using isocyanates, and the ionizing radiation curing method using crosslinking monomers (such as polyfunctional acrylates) and photopolymerization initiators (typically the photocuring method). In one embodiment, the anti-reflective layer is provided on the outermost surface of the first protective member. According to the embodiment where the anti-reflective layer is provided on the outermost surface of the first protective member, excellent anti-reflective effects can be obtained in a display system where a space is formed between the semi-reflective mirror 18 and the first phase difference member 20.

[0137] The hard coating preferably possesses sufficient surface hardness, excellent mechanical strength, and excellent light transmittance. The hard coating can be formed from any suitable resin. Typically, the hard coating is formed from a UV-curable resin. Examples of UV-curable resins include polyester, acrylic, polyurethane, amide, silicone, and epoxy resins. The thickness of the hard coating is, for example, 0.5 µm or more, preferably 1 µm or more, and for example, 20 µm or less, preferably 15 µm or less.

[0138] <Adhesive layer>

[0139] The adhesive layer 31 can be composed of any suitable adhesive. Specific examples include acrylic adhesives, rubber adhesives, silicone adhesives, polyester adhesives, polyurethane adhesives, epoxy adhesives, and polyether adhesives. By adjusting the type, quantity, combination, and blending ratio of the monomers in the base resin forming the adhesive, as well as the amount of crosslinking agent, reaction temperature, and reaction time, an adhesive with desired properties can be formulated. The base resin of the adhesive can be used alone or in combination of two or more. An acrylic resin is preferably used as the base resin. Specifically, the adhesive layer is preferably composed of an acrylic adhesive.

[0140] The thickness of the adhesive layer is typically 1µm or more, preferably 5µm or more, more preferably 12µm or more, and typically 60µm or less, preferably 30µm or less, more preferably 23µm or less.

[0141] <Substrate Removal>

[0142] The release substrate 36 is formed of any suitable resin film. Specific examples of materials that are the main components of the resin film include polyethylene terephthalate (PET), polyethylene, and polypropylene. The resin film material can be used alone or in combination. The release substrate can be transparent (e.g., with a haze of 5% or less, or even 3% or less) or opaque. When inspecting an optical film with a surface protective film while the release substrate is attached, the release substrate is preferably transparent.

[0143] A release treatment layer may also be provided on the contact surface between the release substrate 36 and the adhesive layer 31. Examples of release agents forming the release treatment layer include silicone-based release agents, fluorine-based release agents, and long-chain alkyl acrylate-based release agents. Release agents may be used alone or in combination. The thickness of the release treatment layer is typically 50 nm or more and 400 nm or less.

[0144] The thickness of the release substrate is typically 5 µm or more, preferably 20 µm or more, and typically 60 µm or less, preferably 45 µm or less. Further, in the case where a release treatment layer is provided, the thickness of the release substrate is the thickness including the thickness of the release treatment layer.

[0145] Figure 5 FIG. is a schematic cross-sectional view showing an example of the configuration of an optical film applicable to an embodiment of the present invention. The optical film 50b sequentially includes an adhesive layer 32, a second retardation member 22a, and a second protective member 42. The second retardation member 22 and the second protective member 42 are laminated via an adhesive layer 35. The adhesive layer 35 is typically an adhesive layer or an adhesive layer, preferably an adhesive layer. The thickness of the adhesive layer is, for example, 0.05 µm to 30 µm. The surface of the adhesive layer 32 is protected by a release substrate 37 during the period before use. For the optical film 50b, a surface protective film layer is disposed on the side surface of the second protective member 42.

[0146] The optical film 50b can be suitably used for Figure 1 the display system 2 shown in the example below. Specifically, by peeling off the release substrate 37 from the optical film 50b and integrating it with the first lens portion 16 via the exposed adhesive layer 32, a display system in which the second retardation member 22 and the first lens portion 16 are integrated can be manufactured.

[0147] In Figure 5 the example shown, in addition to the second λ / 4 member 22a, the second retardation member 22 includes a member (so-called positive C-plate) 22b having a refractive index characteristic indicating a relationship of nz > nx = ny. The second retardation member 22 has a laminated structure of the second λ / 4 member 22a and the second positive C-plate 22b. Different from the schematic example, the second positive C-plate 22b may be located closer to the second protective member 42 side than the second λ / 4 member 22a, or the second positive C-plate 2 could be omitted. The second λ / 4 member 22a and the second positive C-plate 22b are laminated via an adhesive layer not shown, for example.

[0148] <Second λ / 4 member>

[0149] The in-plane retardation Re(550) and the dispersion wavelength characteristics of the second λ / 4 member 22a are as described in item A.

[0150] The second λ / 4 member preferably has a refractive index characteristic indicating 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, within the range where the effects of the present invention are not lost, there may be a case where ny < nz. The Nz coefficient of the second λ / 4 member is preferably 0.9 to 3, more preferably 0.9 to 2.5, still more preferably 0.9 to 1.5, and most preferably 0.9 to 1.3.

[0151] The second λ / 4 component can be formed from any suitable material that satisfies the above-described characteristics. The second λ / 4 component can be, for example, an extended film of a resin film or a oriented cured layer of a liquid crystal compound. The same description as that for the first λ / 4 component can be applied to the second λ / 4 component, which is an extended film of a resin film or an oriented cured layer of a liquid crystal compound. The first λ / 4 component and the second λ / 4 component can have the same configuration (e.g., forming material, thickness, optical properties, etc.) or different configurations.

[0152] <Second Positive C Board>

[0153] The phase difference Rth (550) in the thickness direction of the second positive C-plate 22b is preferably -20nm to -200nm, more preferably -30nm to -180nm, 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.

[0154] The second positive C-plate is formed from any suitable material that satisfies the above-mentioned characteristics. The same description as that for the first positive C-plate applies to the constituent materials of the second positive C-plate. The first and second positive C-plates may have the same composition (e.g., forming material, thickness, optical properties, etc.) or different compositions.

[0155] <Second protective component>

[0156] The second protective component 42 typically includes a substrate, and preferably has a substrate and a surface treatment layer formed on the substrate. In this case, the surface treatment layer may be located on the outermost surface of the optical film 50b. Details regarding the substrate and the surface treatment layer can be described using the same approach as for the first protective component. According to the embodiment where the anti-reflective layer is disposed as a surface treatment layer on the outermost surface of the second protective component 42, excellent anti-reflective effects can be obtained in a display system where the second phase difference component 22 is integrated with the first lens portion 16 and the reflective portion 14 is integrated with the second lens portion 24, with a space formed between them.

[0157] The same descriptions can be applied to the adhesive layer 32 and the release substrate 37 used for the optical film 50b as to the adhesive layer 31 and the release substrate 36 used for the optical film 50a.

[0158] <Manufacturing Method of Optical Film with Surface Protective Film>

[0159] Optical films with surface protective films can be fabricated by any suitable method. For example, a surface protective film layer can be fabricated by laminating two or more protective film layers (PFs), and then the surface protective film layer can be bonded to the optical film to create an optical film with a surface protective film. Alternatively, for example, an optical film with a surface protective film can be fabricated by sequentially bonding two or more PFs to one side of the optical film. Or, a surface protective film layer can be applied to the outermost component of the optical film (e.g., a protective component), and the component with the surface protective film layer can be laminated with other components to fabricate the optical film, thereby obtaining an optical film with a surface protective film.

[0160] C. Inspection methods for optical films

[0161] The method for inspecting an optical film according to an embodiment of the present invention includes the following steps: peeling off the outermost PF layer from an optical film with a surface protective film as described in item B to obtain an optical film that is at least protected by the innermost PF layer; and using the optical film that is at least protected by the innermost PF layer for defect inspection.

[0162] As described above, according to the optical film with a surface protective film as described in item B, the peeling of the inner PF (e.g., the innermost PF or the middle PF) can be appropriately suppressed when peeling off the outer PF (e.g., the middle PF or the outermost PF). Therefore, by peeling off the outer PF from the optical film with a surface protective film as described in item B, an optical film in a state where it is at least protected by the innermost PF can be appropriately obtained. Here, the surface of the inner PF exposed due to the peeling off of the outer PF prevents the adhesion of scratches, dirt, etc. Therefore, by peeling off the outer PF just before inspection, an optical film in a state where it is protected by clean PF can be used for defect inspection, and false detection of defects caused by scratches or dirt on the PF surface can be suppressed.

[0163] Defect inspection can be performed using any suitable defect inspection device. Known defect inspection devices can be used, with automated optical inspection (AOI) devices being preferred. Examples of documents describing defect inspection devices include: International Publication No. 2011 / 148790, Japanese Patent Application Publication No. 2003-344302, Japanese Patent Application Publication No. 2011-226957, Japanese Patent Application Publication No. 2016-70856, and Japanese Patent Application Publication No. 2021-135219. Defect inspection may also include visual inspection as needed.

[0164] Example

[0165] The present invention will now be specifically described through examples, but the present invention is not limited to these examples. Furthermore, the thickness is a value measured by the following measurement method.

[0166] <Thickness>

[0167] The thickness was measured using a digital micrometer (manufactured by Anritsu, product name "KC-351C").

[0168] <Total light transmittance and haze>

[0169] Regarding the surface protective film, after the release substrate was peeled from the adhesive layer, light was irradiated from the substrate side using a haze meter (Suga Test Instruments Co., Ltd. "HZ-V3"). The haze was calculated according to JIS-K-7136, based on the formula: haze (%) = (Td / Tt) × 100 (Td: diffusion transmittance, Tt: total light transmittance). Total light transmittance was measured according to JIS-K-7316.

[0170] <Water contact angle>

[0171] The water contact angle of the antireflective layer side surface of the optical film was measured. Specifically, it was measured using a contact angle meter (DMo-501, manufactured by Kyowa Surface Science Co., Ltd., control box DMC-2, control / analysis software FAMAS (version 5.0.30)) via the droplet method at 23°C and 50%RH. The amount of distilled water dropped was set to 2µL, and the contact angle was calculated using the θ / 2 method from the image 5 seconds after the drop.

[0172] [Manufacturing Example 1-1: Production of PF1]

[0173] <Acrylic Polymer 1>

[0174] In a reaction vessel equipped with a thermometer, stirrer, cooler, and nitrogen inlet, 96.2 parts by weight of 2-ethylhexyl acrylate (2EHA), 3.8 parts by weight of hydroxyethyl acrylate (HEA), and 0.2 parts by weight of 2,2'-azobisisobutyronitrile (AIBN) as a polymerization initiator were added along with 150 parts by weight of ethyl acetate. Nitrogen gas was introduced for nitrogen replacement while the mixture was slowly stirred at 23°C. The reaction was then carried out at approximately 65°C for 6 hours to produce a solution of acrylic polymer 1 (concentration 40% by weight). The weight average molecular weight of acrylic polymer 1 was 540,000.

[0175] In addition, the Tg of acrylic polymer 1 was calculated using the FOX formula as (-70℃×0.962)+(-15℃×0.038)=(-67.34℃)+(-0.57℃)=-67.91℃.

[0176] <Adhesive Composition 1>

[0177] Relative to 100 parts by weight of the solids component of the acrylic polymer 1 solution, 5 parts by weight of a triisocyanate of hexamethylene diisocyanate (Tosoh Corporation's "Coronate HX") was added as a crosslinking agent. After diluting with toluene to a total solids component of 20% by weight, 3 parts by weight of dibutyltin dilaurate (1% ethyl acetate solution) (0.03 parts by weight of solids component) were added as a crosslinking catalyst, and the mixture was stirred using a disperser to prepare adhesive composition 1.

[0178] <pf1>

[0179] Adhesive composition 1 was applied to the surface (corona-treated side) of a substrate (cyclic olefin film, manufactured by ZEON, Japan, model ZF-16, 50µm thick) and then dried to form an adhesive layer (10µm thick). Next, a release substrate (manufactured by Toyobo, model TG704) was adhered to the surface of the adhesive layer opposite to the substrate.

[0180] This yields PF1 (thickness 60µm) with a haze of less than 1.0% and a total light transmittance of more than 90%.

[0181] [Manufacturing Example 1-2: Making PF2]

[0182] <Acrylic Polymer 2>

[0183] In a reaction vessel equipped with a thermometer, stirrer, cooler, and nitrogen inlet, 100 parts by weight of 2-ethylhexyl acrylate (2EHA) and 4 parts by weight of hexyl acrylate (as monomers), along with 0.2 parts by weight of 2,2'-azobisisobutyronitrile (AIBN) as a polymerization initiator, were added together with 150 parts by weight of ethyl acetate. Nitrogen gas was introduced for nitrogen replacement while the mixture was slowly stirred at 23°C. The polymerization reaction was then carried out for 6 hours at approximately 65°C to prepare a solution of acrylic polymer 2 (concentration 40% by weight). The weight average molecular weight of acrylic polymer 2 was 530,000.

[0184] <Adhesive Composition 2>

[0185] Ethyl acetate was added to a solution of acrylic polymer 2 and diluted to a concentration of 20% by weight. In 500 parts by weight of this solution (100 parts by weight of solids), 4 parts by weight of triisocyanate of hexamethylene diisocyanate ("Coronate HX" manufactured by Tosoh Corporation) and 0.2 parts by weight of surfactant ("Aqualon HS-10" manufactured by Daiichi Kogyo Pharmaceutical Co., Ltd.) were added as crosslinking agents and stirred to prepare adhesive composition 2.

[0186] <pf2>

[0187] Adhesive composition 2 was applied to the surface (corona-treated side) of a substrate (PET film, manufactured by Mitsubishi Chemical Co., model T100C38, thickness 38µm) and then dried to form an adhesive layer (thickness 20µm). Next, a release liner (manufactured by Toyobo Co., model TG704) was adhered to the surface of the adhesive layer opposite to the substrate.

[0188] Thus, PF2 (thickness 58µm) with a haze of less than 3.0% and a total light transmittance of more than 90% was obtained.

[0189] [Manufacturing Example 1-3: Making PF3]

[0190] <Adhesive Composition 3>

[0191] Relative to 100 parts by weight of the solids component of the acrylic polymer 1 solution obtained in Manufacturing Example 1-1, 4 parts by weight of a triisocyanate of hexamethylene diisocyanate (Tosoh Corporation's "Coronate HX") was added as a crosslinking agent. After diluting with toluene to a total solids component of 20% by weight, 3 parts by weight of dibutyltin dilaurate (1% toluene solution) (0.03 parts by weight of solids component) were added as a crosslinking catalyst, and the mixture was stirred using a disperser to prepare adhesive composition 3.

[0192] <pf3>

[0193] Adhesive composition 3 was applied to the surface (corona-treated side) of a substrate (PET film, manufactured by Mitsubishi Chemical Co., model T100C38, thickness 38µm) and then dried to form an adhesive layer (thickness 10µm). Next, a release liner (manufactured by Toyobo Co., model TG704) was adhered to the surface of the adhesive layer opposite to the substrate.

[0194] Thus, PF3 (thickness 48µm) with a haze of less than 3.0% and a total light transmittance of more than 90% was obtained.

[0195] [Manufacturing Examples 1-4: Making PF4]

[0196] <Adhesive Composition 4>

[0197] 100 parts by weight of TAKENATE D-101E (manufactured by Mitsui Chemicals Co., Ltd.) was added as a crosslinking agent, based on the solid content of the solution of acrylic polymer 1 obtained in Manufacturing Example 1-1. The mixture was diluted with toluene to a total solid content of 29% by weight and stirred using a disperser to prepare adhesive composition 4.

[0198] <pf4>

[0199] Adhesive composition 4 was applied to the surface (corona-treated side) of a substrate (PET film, manufactured by Mitsubishi Chemical Co., model T100C38, thickness 38µm) and then dried to form an adhesive layer (thickness 23µm). Next, a release liner (manufactured by Toyobo Co., model TG704) was adhered to the surface of the adhesive layer opposite to the substrate.

[0200] Thus, PF4 (thickness 61µm) with a haze of less than 3.0% and a total light transmittance of more than 90% was obtained.

[0201] The peel strength of PF1~4 was measured as follows. The measurements were conducted at 23°C and 50%RH. The results are shown in Table 1.

[0202] (1) Under a pressure of 0.25 MPa and a feed speed of 0.3 m / min, the adhesive layer of the surface protective film A of the test object is rolled onto the bonded body B and left for 30 minutes to produce the test sample C (size: length 150 mm, width 25 mm).

[0203] (2) The test sample C is fixed to a metal or glass plate with the adhesive B facing down by means of double-sided tape (manufactured by Nitto Denko Corporation, product name "No.5000NS").

[0204] (3) such as Figure 6A and 6B As shown, adhesive tape T (manufactured by Nitto Denko Corporation, product name "No.31B", size: length 50mm, width 20mm) is attached to the surface protective film A of the test sample C with one end exposed and the length direction parallel. The end is held and stretched in the direction of the arrow, and the peel force at this time is measured (peel angle 180°, peel speed 300mm / min).

[0205] [Table 1]

[0206]

[0207] *1: PF1 is bonded to the surface of the antireflective layer of the optical film 1 fabricated in Manufacturing Example 4.

[0208] *2: PF2-4 is bonded to the substrate side surface of PF1.

[0209] [Manufacturing Example 2: Fabrication of Polarizing Film 1]

[0210] Using a roll stretcher, a long roll of polyvinyl alcohol (PVA) resin film (manufactured by Kuraray, product name "PE3000") with a thickness of 30µm is uniaxially stretched in the length direction to make it 5.9 times its original length. At the same time, swelling, dyeing, crosslinking, and washing processes are carried out, and finally drying is performed to produce an absorptive polarizing film with a thickness of 12µm.

[0211] Specifically, the swelling treatment involves extending the film by 2.2 times while treating it in pure water at 20°C. Next, the dyeing treatment involves extending the film by 1.4 times while treating it in an aqueous solution at 30°C containing iodine and potassium iodide in a weight ratio of 1:7, with the iodine concentration adjusted to achieve a monomer transmittance of 45.0% for the resulting absorptive polarizing film. Furthermore, the crosslinking treatment employs a two-stage process. The first stage involves extending the film by 1.2 times while treating it in an aqueous solution containing boric acid and potassium iodide at 40°C. The boric acid content in the first stage crosslinking treatment aqueous solution is 5.0 wt%, and the potassium iodide content is 3.0 wt%. The second stage crosslinking treatment involves extending the film by 1.6 times while treating it in an aqueous solution containing boric acid and potassium iodide at 65°C. The boric acid content in the second stage crosslinking treatment aqueous solution is 4.3 wt%, and the potassium iodide content is 5.0 wt%. Finally, the washing treatment is performed in an aqueous solution of potassium iodide at 20°C. The potassium iodide content of the aqueous solution used for washing was set to 2.6% by weight. Finally, the film was dried at 70°C for 5 minutes to obtain an absorptive polarizing film.

[0212] A cellulose triacetate (TAC) resin film with a hard coating (HC) (TAC thickness: 25 µm, HC thickness: 7 µm) was laminated as a protective layer on one side of the obtained absorptive polarizing film, and a cyclic olefin resin film (thickness: 13 µm) was laminated as a protective layer on the other side. Specifically, the coatings were applied to a total thickness of approximately 1 µm for the curing adhesive, and the lamination was performed using a rolling mill. Then, UV light was irradiated from the TAC film side to cure the adhesive.

[0213] Thus, a polarizing film 1 with the structure of [TAC film (protective layer) / absorption type polarizing film / COP film (protective layer)] is obtained.

[0214] [Manufacturing Example 3: Fabrication of Protective Component 1]

[0215] (Modulation of hard coating forming materials)

[0216] A hard coating forming material was prepared by mixing 50 parts of a carbamate acrylate oligomer (manufactured by Shin-Nakamura Chemical Co., Ltd., "NK Oligo UA-53H"), 30 parts of a multifunctional acrylate with pentaerythritol triacrylate as the main component (manufactured by Osaka Organic Chemical Industry Co., Ltd., trade name "Viscoat #300"), 20 parts of 4-hydroxybutyl acrylate (manufactured by Osaka Organic Chemical Industry Co., Ltd.), 1 part of a leveling agent (manufactured by DIC Corporation, "GRANDIC PC4100"), and 3 parts of a photopolymerization initiator (manufactured by Ciba Japan Corporation, "IRGACURE 907"), and diluting with methyl isobutyl ketone to achieve a solid component concentration of 50%.

[0217] (Preparation of coating liquid for forming high refractive index layer)

[0218] A mixture of 100 parts by weight of a multifunctional acrylate (manufactured by Arakawa Chemical Industry Co., Ltd., trade name "OPSTAR KZ6728", solids content 20% by weight), 3 parts by weight of a leveling agent (manufactured by DIC, "GRANDIC PC4100"), and 3 parts by weight of a photopolymerization initiator (manufactured by BASF, trade name "OMNIRAD907", solids content 100% by weight) was prepared. Butyl acetate was used as a diluent to bring the solids content to 12% by weight, and the mixture was stirred to prepare a coating solution for forming a high refractive index layer.

[0219] (Preparation of coating solution for forming low refractive index layer)

[0220] The mixture comprises 100 parts by weight of a multifunctional acrylate (manufactured by Osaka Organic Chemical Industry Co., Ltd., trade name "Viscoat #300", solid content 100 wt%), mainly composed of pentaerythritol triacrylate; 150 parts by weight of hollow nano-silica particles (manufactured by Nichibukai Catalyst Chemical Industry Co., Ltd., trade name "THRULYA 5320", solid content 20 wt%, weight average particle size 75 nm); 50 parts by weight of solid nano-silica particles (manufactured by Nissan Chemical Industry Co., Ltd., trade name "MEK-2140Z-AC", solid content 30 wt%, weight average particle size 10 nm); 12 parts by weight of a fluorinated additive (manufactured by Shin-Etsu Chemical Industry Co., Ltd., trade name "KY-1203", solid content 20 wt%); and 3 parts by weight of a photopolymerization initiator (manufactured by BASF, trade name "OMNIRAD907", solid content 100 wt%). To this mixture, a mixed solvent consisting of TBA (tert-butanol), MIBK (methyl isobutyl ketone), and PMA (propylene glycol monomethyl ether acetate) in a weight ratio of 60:25:15 is added as a diluent to bring the total solid content to 4% by weight. The mixture is then stirred to prepare a coating solution for forming a low refractive index layer.

[0221] The aforementioned hard coating material was applied to an acrylic film (40 µm thick) with an lactone ring structure as a substrate and heated to 90 °C for 1 minute. The heated coating layer was then irradiated with a high-pressure mercury lamp, accumulating a light intensity of 300 mJ / cm². 2 The ultraviolet light hardens the coating layer, creating an acrylic film (44µm thick) with a hard coating layer of 4µm thickness.

[0222] Next, the high-refractive-index layer forming solution was applied to the hard coating layer using a wire rod, and the applied solution was heated at 80°C for 1 minute to dry, forming a coating film. The dried coating film was then irradiated with a high-pressure mercury lamp, accumulating a light intensity of 300 mJ / cm². 2 The ultraviolet light causes the coating to harden, forming a high refractive index layer with a thickness of 140 nm.

[0223] Next, the low-refractive-index layer forming solution was applied onto the high-refractive-index layer using a wire rod, and the applied solution was heated at 80°C for 1 minute to dry, forming a coating film. The dried coating film was then irradiated with a high-pressure mercury lamp, accumulating a light intensity of 300 mJ / cm². 2 The ultraviolet light causes the coating to harden, forming a low-refractive-index layer with a thickness of 105 nm. This creates an anti-reflective layer on the hard coating, consisting of a high-refractive-index layer and a low-refractive-index layer.

[0224] The above describes the protective component 1, which has a structure of [anti-reflective layer / hard coating / substrate]. The water contact angle of the side surface of the anti-reflective layer is 110°.

[0225] [Manufacturing Example 4: Fabrication of Optical Film 1]

[0226] The substrate surface of the protective member 1 is attached to the TAC film surface of the polarizing film 1 obtained in Manufacturing Example 2 via an acrylic adhesive layer (25µm thick). In addition, an acrylic adhesive layer (25µm thick) formed on the release substrate is attached to the COP film surface of the polarizing film 1 to create an optical film 1 having a structure of [release substrate / adhesive layer / polarizing film 1 / protective member 1].

[0227] [Example 1]

[0228] The adhesive layer of PF2 obtained in Manufacturing Examples 1-2 is bonded to the substrate surface of PF1 obtained in Manufacturing Examples 1-1 to form a surface protective film layer 1 consisting of PF1 as the innermost PF layer and PF2 as the outermost PF layer.

[0229] The adhesive layer of the surface protective film layer 1 (more specifically, the adhesive layer of PF1) is attached to the surface of the protective component 1 of the optical film 1 to obtain the optical film 1 with the surface protective film.

[0230] [Example 2]

[0231] The adhesive layer of PF3 obtained in Manufacturing Examples 1-3 is bonded to the substrate surface of PF1 obtained in Manufacturing Example 1-1 to form a surface protective film layer 2 consisting of PF1 as the innermost PF layer and PF3 as the outermost PF layer.

[0232] The adhesive layer of the surface protective film layer 2 (more specifically, the adhesive layer of PF1) is attached to the surface of the protective component 1 of the optical film 1 to obtain the optical film 2 with the surface protective film.

[0233] [Comparative Example 1]

[0234] The adhesive layer of PF4 obtained in Manufacturing Examples 1-4 is bonded to the substrate surface of PF1 obtained in Manufacturing Example 1-1 to form a surface protective film layer 3 consisting of PF1 as the innermost PF layer and PF4 as the outermost PF layer.

[0235] The adhesive layer of the surface protective film layer 3 (more specifically, the adhesive layer of PF1) is attached to the surface of the protective component 1 of the optical film 1 to obtain an optical film C1 with a surface protective film.

[0236] <Peeling Test>

[0237] The optical films with surface protective films obtained in the examples and comparative examples were cut into rectangles (dimensions: length 32mm, width 28mm) and the four corners were removed (corner removal size: 2mm). The resulting samples were used as test samples.

[0238] (1) Peeling with the short side as the starting point

[0239] like Figure 7A As shown, a 50mm long and 20mm wide adhesive tape T (manufactured by Nitto Denko Corporation, product name "No. 31B") was applied to the surface protective film layer 60 of the test sample 100, with its length parallel and one end exposed. Holding this end, the outermost PF layer was peeled off at a peeling speed of 300mm / min and a peeling angle of 90° or 180°. Tests were conducted at a N number of 25 for each peeling angle. The number of times the innermost and outermost PF layers were peeled off simultaneously (NG number) is shown in Table 2.

[0240] (2) Peeling starting from the corner

[0241] like Figure 7B As shown, an adhesive tape T (manufactured by Nitto Denko Corporation, product name "No. 31B") with a length of 50 mm and a width of 20 mm was attached to the surface protective film layer 60 of the test sample 100, with its length direction forming a 45° angle with the length direction of the test sample 100 and one end exposed. Holding this one end, the outermost PF layer was peeled off at a peeling speed of 300 mm / min and a peeling angle of 90° or 180°. For each peeling angle, tests were conducted with a N number of 25. The number of times the innermost PF layer and the outermost PF layer were peeled off simultaneously (NG number) is shown in Table 2.

[0242] [Table 2]

[0243]

[0244] As shown in Table 2, for the embodiment where P2 is less than 3.5 times P1, the optical film with a surface protective film is not affected by the peeling start point and peeling angle, and suppresses the simultaneous peeling of the inner PF when peeling the outermost PF.

[0245] Industrial availability

[0246] The optical film with a surface protective film according to embodiments of the present invention can be appropriately used, for example, in the manufacture of display systems such as VR goggles.

[0247] Explanation of reference numerals in the attached figures

[0248] 2: Display System

[0249] 12: Display element

[0250] 14: Reflector

[0251] 16: First lens section

[0252] 18: Semi-reflective mirror

[0253] 20: First phase difference component

[0254] 22: Second phase difference component

[0255] 24: Second lens section

[0256] 50: Optical film

[0257] 60: Surface protective film layer

[0258] 62: Innermost surface protective film

[0259] 64: Outermost surface protective film

[0260] 66: Intermediate surface protective film

[0261] 100: Optical film with surface protective coating

Claims

1. An optical film with a surface protective film, characterized in that, It includes an optical film and a surface protective film layer disposed on one side of the optical film. The surface protective film layer comprises two or more surface protective films having a substrate and an adhesive layer. The peel force P1 of the innermost surface protective film relative to the optical film and the peel force P2 of the outermost surface protective film relative to the adjacent surface protective film satisfy the following relationship (1): P2≤3.5×P1 (1) The innermost surface protective film is the film of the surface protective film layer that is disposed closest to the optical film, and the outermost surface protective film is the film of the surface protective film layer that is disposed on the outermost side.

2. The optical film with a surface protective film as described in claim 1, characterized in that, The surface protective film layer is composed of the innermost surface protective film, the middle surface protective film, and the outermost surface protective film. The peel force P2 of the outermost protective film relative to the intermediate protective film and the peel force P3 of the intermediate protective film relative to the innermost protective film satisfy the following relationships (2) and (3): P2≤2.5×P3 (2), P3≤2×P1 (3).

3. The optical film with a surface protective film as described in claim 1, characterized in that, The ratio (T1 / T2) of the thickness T1 of the innermost protective film to the thickness T2 of the outermost protective film is 1.03 or more.

4. The optical film with a surface protective film as described in claim 1, characterized in that, The bending strength of the substrate of the innermost surface protective film at 23°C is greater than that of the substrate of the outermost surface protective film at 23°C.

5. The optical film with a surface protective film as described in claim 1, characterized in that, The surface of the protective film layer of the optical film is an anti-reflective layer.

6. The optical film with a surface protective film as described in claim 1, characterized in that, The water contact angle of the surface protective film layer of the optical film is greater than 80°.

7. A method for inspecting an optical film, characterized in that, Includes the following steps: The outermost surface protective film is peeled off from the optical film with a surface protective film according to any one of claims 1 to 6 to obtain the optical film in a state that is at least protected by the innermost surface protective film; The optical film, which is at least protected by the innermost surface protective film, is used for defect inspection.

Images