Optical laminates and their manufacturing methods

Abstract

This invention provides an optical laminate and its manufacturing method. The optical laminate can prevent abnormal discharge to the marking layer at display defect sites and marks defect sites with fewer steps and lower cost. An optical laminate is characterized in that it is an optical laminate formed by stacking a substrate and an optical functional layer, wherein the optical functional layer comprises an inorganic oxide or an inorganic nitride, and a marking layer is locally formed on the surface of the optical functional layer. The marking layer is made of a semiconductor material and has a reflectivity of 40% or more for light in the wavelength range of 400 nm to 700 nm.

Description

Technical Field

[0001] The present invention relates to an optical laminate and a method for manufacturing the same, the optical laminate comprising a marking layer that indicates the location of defects generated in the optical functional layer.

[0002] This application claims priority based on Japanese Patent Application No. 2021-121879, filed in Japan on July 26, 2021, the contents of which are incorporated herein by reference. Background Technology

[0003] For example, in flat panel displays (FPDs), touch panels, solar cells, and other applications, various optical laminates (anti-reflective films) are used to prevent surface reflection of incident external light and improve visual visibility.

[0004] Previously, antireflective films have been proposed that consist of a multilayer film (optical functional layer) on a transparent substrate, in which a high-refractive-index layer and a low-refractive-index layer are sequentially stacked. In the manufacture of such antireflective films, an optical functional layer composed of a high-refractive-index film and a low-refractive-index film is formed on one side of the transparent substrate by, for example, by sputtering, stacking a metal oxide film or a metal nitride film. Then, surface treatments such as the formation of an antifouling layer are typically performed as needed.

[0005] During the manufacture of such antireflective films, defects sometimes occur in the optical functional layer. Such defects are detected by optical inspection devices or the like. Furthermore, it is known that when defects are detected in the optical functional layer, the location of the defects is marked so that they can be easily identified in subsequent processes (e.g., Patent Documents 1-3).

[0006] For example, Patent Document 1 discloses a marking forming method in which an embossing roller is pressed on the film surface, including the area of ​​the detected defect, to perform embossing and form a mark at the defect location.

[0007] Furthermore, Patent Document 2 discloses a method for manufacturing a double-sided laminated film, which involves forming recesses and through holes in areas including detected defects, applying ink, etc., to form markings at the defect locations.

[0008] In addition, Patent Document 3 discloses a defect marking method in which a marking pen is used to write marks on the defective parts of an optical film.

[0009] However, the methods disclosed in these patent documents 1-3 require not only a sputtering device for forming the optical functional layer, but also a transfer device for forming the embossing, an ink jetting device, etc., which may complicate the process and increase manufacturing costs. Furthermore, defects are more likely to occur when physical pressure is applied during embossing or other processes.

[0010] Therefore, for example, it is also considered to mark the defect sites by forming a sputtered film at the defect sites using a sputtering device in conjunction with the formation of the optical functional layer. In such a method, the marking of the defect sites is also formed by the same sputtering method as the formation of the optical functional layer, thus having the advantage of being able to perform tandem processes.

[0011] Existing technical documents

[0012] Patent documents

[0013] Patent Document 1: Japanese Patent Application Publication No. 2017-137527

[0014] Patent Document 2: Japanese Patent Application Publication No. 2019-173061

[0015] Patent Document 3: Japanese Patent Application Publication No. 2014-016217 Summary of the Invention

[0016] The problem that the invention aims to solve

[0017] As mentioned above, when marking defect locations by sputtering, it is advisable to use a highly reflective metallic material for marking to improve visual visibility. However, the defect marking layer formed using a metallic material is a conductive sputtered metal film. Therefore, in subsequent processes such as corona treatment, abnormal discharge may be induced into the marking layer, causing further damage to the optical functional layer.

[0018] The present invention was made in consideration of the following situation, and its object is to provide an optical laminate and a method for manufacturing the same, wherein the optical laminate can prevent abnormal discharge to the marking layer that displays defective areas, and can mark defective areas with fewer steps and lower cost.

[0019] Solution for solving the problem

[0020] In other words, in order to solve the above problems, the present invention proposes the following solution.

[0021] The optical laminate of the present invention is characterized in that it is an optical laminate formed by stacking a substrate and an optical functional layer, wherein the optical functional layer comprises an inorganic oxide or an inorganic nitride, and a marking layer is locally formed on the surface of the optical functional layer. The marking layer is made of a semiconductor material and has a reflectivity of more than 40% for light in the range of wavelengths above 400 nm and below 700 nm.

[0022] According to the present invention, by forming a marking layer on the defect site of the optical functional layer using a semiconductor material having a reflectivity of 40% or more for light in the range of wavelengths 400 nm or more and 700 nm or less, the defect site can be easily detected using visible light in subsequent processes, and abnormal discharge to the marking layer can be effectively suppressed when the optical laminate 10 is subjected to corona treatment or the like in subsequent processes.

[0023] Alternatively, in this invention, the marking layer may comprise germanium or silicon.

[0024] According to the present invention, the marking layer may also be formed such that at least a portion overlaps with the defective portion of the optical functional layer.

[0025] According to the present invention, the marking layer may also be a sputtered film formed by sputtering.

[0026] According to the present invention, the optical laminate may also be an anti-reflective film, and the optical functional layer may be composed of a laminate consisting of alternating layers of low refractive index layer and high refractive index layer.

[0027] The method for manufacturing an optical laminate of the present invention is characterized in that it is a method for manufacturing an optical laminate according to the claims, comprising: an optical functional layer forming step, wherein the optical functional layer is formed on the substrate; a defect inspection step, wherein defects of the optical functional layer are inspected; and a defect area display step, wherein when a defect is detected in the defect inspection step, a marking layer is formed in the area including the defect.

[0028] Invention Effects

[0029] According to the present invention, an optical laminate and a method for manufacturing the same are provided, wherein the optical laminate can prevent abnormal discharge to the marking layer of the display defect site, and the defect site can be marked with fewer steps and at lower cost. Attached Figure Description

[0030] Figure 1 This is a top view of an optical laminate according to an embodiment of the present invention, viewed from above.

[0031] Figure 2 yes Figure 1 A cross-sectional view of an optical laminate.

[0032] Figure 3 This is a schematic diagram showing an optical laminate manufacturing apparatus used in a method for manufacturing optical laminates.

[0033] Figure 4 This is a graph representing the results of the embodiment. Detailed Implementation

[0034] Hereinafter, an optical laminate according to one embodiment of the present invention and its manufacturing method will be described with reference to the accompanying drawings. It should be noted that the embodiments shown below are specifically described for a better understanding of the spirit of the invention, and are not intended to limit the invention unless otherwise specified. Furthermore, in the accompanying drawings used in the following description, for ease of understanding of the features of the invention, some parts that will be considered major components are sometimes shown in enlarged form, and the dimensions and proportions of each component may not be the same as in reality.

[0035] (Optical laminate)

[0036] As an example of an optical laminate according to one embodiment of the present invention, an anti-reflective film will be described.

[0037] Figure 1 This is a top view of an optical laminate according to one embodiment of the present invention, viewed from above. Furthermore, Figure 2 yes Figure 1 A cross-sectional view of an optical laminate.

[0038] The optical laminate (anti-reflective film) 10 of this embodiment has a transparent substrate (substrate) 11 and an optical functional layer 12 formed on one side of the transparent substrate 11. In addition, a marking layer 13 is formed in such a way that it overlaps with the defect portion D of the optical functional layer 12.

[0039] The transparent substrate 11 can be formed of any transparent material capable of transmitting light in the visible light region; for example, a plastic film is preferred. Specific examples of materials constituting the plastic film include: polyester resins, acetate resins, polyethersulfone resins, polycarbonate resins, polyamide resins, polyimide resins, polyolefin resins, (meth)acrylic resins, polyvinyl chloride resins, polyvinylidene chloride resins, polystyrene resins, polyvinyl alcohol resins, polyarylate resins, and polyphenylene sulfide resins.

[0040] The transparent substrate 11 may also contain reinforcing materials, such as cellulose nanofibers and nano-silica, provided that the optical properties are not significantly impaired. Polyester resins, acetate resins, polycarbonate resins, and polyolefin resins are particularly preferred. Specifically, cellulose triacetate (TAC) substrate is preferred.

[0041] In addition, glass films can also be used as inorganic substrates.

[0042] The transparent substrate 11 can also be a film endowed with optical or physical functions. Examples of substrates with optical or physical functions include: polarizing plates, phase difference compensation films, heat ray blocking films, transparent conductive films, brightness-enhancing films, and barrier-enhancing films.

[0043] The thickness of the transparent substrate 11 is not particularly limited, but is preferably 25 μm or more. More preferably, the thickness of the transparent substrate 11 is 40 μm or more.

[0044] If the thickness of the transparent substrate 11 is 25 μm or more, the rigidity of the substrate itself is ensured, and wrinkles are not easily generated even when stress is applied to the optical laminate 10. If the thickness of the transparent substrate 11 is 40 μm or more, wrinkles are even less likely to occur, which is preferred.

[0045] As described later in the method for manufacturing the optical laminate, when manufacturing the optical laminate 10 in a roll-to-roll manner, the thickness of the transparent substrate 11 is preferably 1000 μm or less, more preferably 600 μm or less. If the thickness of the transparent substrate 11 is 1000 μm or less, it is easy to roll the optical laminate 10 during manufacturing and the manufactured optical laminate 10 into a roll, enabling efficient manufacturing of the optical laminate 10. Furthermore, if the thickness of the transparent substrate 11 is 1000 μm or less, it is possible to achieve thinner and lighter optical laminate 10. If the thickness of the transparent substrate 11 is 600 μm or less, it is preferable to manufacture the optical laminate 10 more efficiently and further achieve thinner and lighter optical laminate 10.

[0046] Optical functional layer 12 is the layer that embodies optical functions. The optical functions referred to here are the functions that control the properties of light, such as reflection, transmission, and refraction. Examples include: anti-reflection function, selective reflection function, anti-glare function, and lens function.

[0047] The optical functional layer 12 can be any type of layer, such as an anti-reflective layer, a selective reflection layer, or an anti-glare layer. In this embodiment, an anti-reflective layer is formed as the optical functional layer 12.

[0048] The optical functional layer 12 is a laminate formed by sequentially stacking a high refractive index layer 12a and a low refractive index layer 12b from the transparent substrate 11 side. It should be noted that the number of layers of the high refractive index layer 12a and the low refractive index layer 12b can be set to any number, such as two or more layers as in this embodiment.

[0049] In the optical laminate 10 of this embodiment, the optical functional layer 12 is a layer composed of a low-refractive-index layer 12b and a high-refractive-index layer 12a. Therefore, light incident from the low-refractive-index layer 12b side, such as ambient light, is diffused by the optical functional layer 12. Thus, an anti-reflection function is obtained to prevent ambient light incident from the low-refractive-index layer 12b side from being reflected in one direction. Therefore, if such an optical laminate 10 is provided, for example, on the display surface side of a display device, the reflection of ambient light can be suppressed, improving the visual clarity of the display device.

[0050] The optical functional layer 12 is made of a material containing inorganic oxides or inorganic nitrides.

[0051] Considering ease of acquisition and cost, the low refractive index layer 12b can be made of silicon oxide (SiO2). A single layer of SiO2 is colorless and transparent. For example, the low refractive index layer 12b only needs to contain more than 50% by mass of SiO2.

[0052] Preferably, the low refractive index layer 12b contains, in addition to SiO2, Na for example, to improve durability, Zr, Al or N for improving hardness, and Zr or Al for improving alkali resistance.

[0053] The refractive index of the low refractive index layer 12b is preferably 1.20 or higher and 1.60 or lower, more preferably 1.30 or higher and 1.50 or lower.

[0054] In addition, the thickness of the low refractive index layer 12b only needs to be in the range of 1 nm or more and 200 nm or less, and can be appropriately selected according to the wavelength range required for the anti-reflection function.

[0055] For example, the high refractive index layer 12a can be composed of: niobium pentoxide (Nb₂O₅, refractive index 2.33), titanium oxide (TiO₂, refractive index 2.33 or higher and 2.55 or lower), tungsten oxide (WO₃, refractive index 2.2), cerium oxide (CeO₂, refractive index 2.2), tantalum pentoxide (Ta₂O₅, refractive index 2.16), zinc oxide (ZnO, refractive index 2.1), indium tin oxide (ITO, refractive index 2.06), zirconium oxide (ZrO₂, refractive index 2.2), etc. Furthermore, if it is desired to impart conductive properties to the high refractive index layer 12a, ITO or indium zinc oxide (IZO) can be used, for example.

[0056] The thickness of the high refractive index layer 12a can be, for example, above 1 nm and below 200 nm, and can be appropriately selected according to the wavelength range required for anti-reflection function.

[0057] In this embodiment, the optical functional layer 12 uses a layer made of niobium pentoxide (Nb2O5, refractive index 2.33) as the high refractive index layer 12a and a layer made of silicon oxide (SiO2) as the low refractive index layer 12b.

[0058] It should be noted that the optical laminate 10 may also form a hard coating or an adhesive layer between the transparent substrate 11 and the optical functional layer 12.

[0059] The hard coating can be a layer consisting solely of an adhesive resin, or a layer containing an adhesive resin and, to the extent that it does not impair transparency, a filler. As the filler, an organic filler, an inorganic filler, or a filler consisting of both organic and inorganic substances can be used.

[0060] As the adhesive resin used in the hard coating, a transparent adhesive resin is preferred, such as an ionizing radiation-curing resin, a thermoplastic resin, or a thermosetting resin that is cured by ultraviolet light or an electron beam. Furthermore, the hard coating can be a single layer or a multilayered layer. In addition, the hard coating can be further endowed with known functions such as ultraviolet absorption properties, anti-static properties, refractive index adjustment functions, and hardness adjustment functions.

[0061] The bonding layer is formed to improve the adhesion between the transparent substrate 11 (an organic material film), the hard coating layer, and the optical functional layer 12 (an inorganic material film). The bonding layer is preferably composed of an oxygen-deficient metal oxide or a metal. An oxygen-deficient metal oxide refers to a metal oxide in which the number of oxygen atoms is insufficient compared to its stoichiometric composition. Examples of oxygen-deficient metal oxides include: SiOx, AlOx, TiOx, ZrOx, CeOx, MgOx, ZnOx, TaOx, SbOx, SnOx, and MnOx. Furthermore, examples of metals include: Si, Al, Ti, Zr, Ce, Mg, Zn, Ta, Sb, Sn, Mn, and In. The bonding layer can be, for example, a layer in SiOx where x is greater than 0 and less than 2.0.

[0062] From the viewpoint of maintaining transparency and obtaining good optical properties, the thickness of the sealing layer is preferably greater than 0 nm and less than 20 nm, and particularly preferably greater than 1 nm and less than 10 nm.

[0063] The marking layer 13 is formed such that at least a portion overlaps with the defect site D generated during the manufacturing stage of the optical functional layer 12.

[0064] The marking layer 13 is made of a semiconductor material with a reflectivity of more than 40% for light in the range of wavelengths above 400 nm and below 700 nm.

[0065] Examples of semiconductor materials constituting the marking layer 13 include: intrinsic semiconductors composed of single elements, p-type or n-type semiconductors in which trace amounts of group III or group V elements have been added, and compound semiconductors composed of multiple elements.

[0066] In this embodiment, the marking layer 13 uses a sputtered film formed by sputtering a material containing germanium or silicon. More specifically, examples include compounds containing germanium, iron silicides of iron, titanium silicides, etc., in a range of 5% to 10%.

[0067] Among these considerations, considering the sputtering-based film formation rate and ease of acquisition compared to silicon, which is often used as a semiconductor, it is particularly preferable to form the marker layer 13 by sputtering with germanium as the target. Germanium also has a high film formation rate among semiconductor materials, so sputtering film formation can be performed at low power compared to other semiconductor materials. As a result, thermal damage to the optical functional layer 12 during the formation of the marker layer 13 can be suppressed.

[0068] The thickness of the marking layer 13 is not particularly limited as long as the desired reflectivity is achieved; for example, it is preferably 10 nm or more and 30 nm or less. When the marking layer 13 is formed to a thickness exceeding 30 nm, the time required for film formation increases, and correspondingly, excessive heat is applied during sputtering, potentially leading to greater thermal damage to the optical functional layer 12. Furthermore, if the thickness of the marking layer 13 is less than 10 nm, the desired reflectivity may not be achieved, particularly making it difficult to detect visually.

[0069] The conductivity of the marker layer 13 only needs to be within the range that can suppress corona discharge, for example, 1 × 10⁻⁶. 3 (S / cm) or higher and 1×10 8 The range below (S / cm) is acceptable.

[0070] The marking layer 13 can be formed in a planar shape that completely covers the defect portion D of the optical functional layer 12, or it can be formed to overlap only a portion of the planar shape of the defect portion D. The film formation range can be appropriately selected by considering the ease of inspection of the marking layer 13 in subsequent processes and the film formation speed of the marking layer 13.

[0071] As described above, according to the optical laminate 10 of this embodiment, by forming a marking layer 13 on the defect site D of the optical functional layer 12 using a semiconductor material having a reflectivity of 40% or more for visible light in the wavelength range of 400 nm or more and 700 nm or less, it is easy to detect the defect site using visible light in subsequent processes, and when the optical laminate 10 is subjected to corona treatment or the like in subsequent processes, abnormal discharge to the marking layer 13 can be effectively suppressed.

[0072] (Manufacturing method of optical laminates)

[0073] Next, one embodiment of the method for manufacturing the optical laminate described in the above embodiments will be described.

[0074] In this embodiment, as an example of a method for manufacturing the optical laminate 10, a so-called roll-to-roll manufacturing example is described, in which the optical laminate 10 is manufactured by using a transparent substrate 11 wound into a roll and then rolled into a roll.

[0075] First, a transparent substrate (substrate) 11 wound into a roll is unwound. Then, an optical functional layer forming process is performed to form an optical functional layer 12 on one side 11a of the transparent substrate 11. Next, a defect inspection process is performed to check for defects in the formed optical functional layer 12. Then, if defects are detected in the optical functional layer 12 during the defect inspection process, a defect area display process is performed, forming a marking layer in the area including the defect. Finally, after a surface treatment process to process the surface of the optical functional layer 12, the formed optical laminate 10 is wound up.

[0076] It should be noted that the process may also include: a hard coating forming process, in which a hard coating is formed on the transparent substrate 11 after the transparent substrate 11 is unwound; and an adhesive layer forming process, in which an adhesive layer is formed. Furthermore, the process may also include: an optical functional layer forming process, in which an antifouling layer is formed after a surface treatment process.

[0077] In the manufacturing method of the optical laminate 10 of this embodiment, the optical functional layer formation process, the defect inspection process, the defect area display process, and the surface treatment process are preferably performed continuously while the optical laminate is under reduced pressure during manufacturing. When these optical functional layer formation processes, defect inspection processes, defect area display processes, and surface treatment processes are performed continuously while the optical laminate is under reduced pressure during manufacturing, a known thin film forming apparatus can be used as a sputtering apparatus, for example.

[0078] Figure 3 This is a schematic diagram showing the optical laminate manufacturing apparatus used in the optical laminate manufacturing method of this embodiment.

[0079] Specifically, the manufacturing apparatus that can be used in the manufacturing method of the optical laminate in this embodiment can be listed as follows: Figure 3 The optical laminate manufacturing apparatus 20 shown.

[0080] The optical laminate manufacturing apparatus 20 includes: a winding and unwinding device 4, a sputtering device 1, a surface treatment device 2, and a winding and take-up device 5. For example... Figure 3 As shown, the unwinding device 4, sputtering device 1, surface treatment device 2, and winding device 5 are connected in sequence. The optical laminate manufacturing apparatus 20 is a roll-to-roll manufacturing apparatus in which a substrate is unwound from a roll, continuously passed through the connected devices, and then wound up, thereby continuously forming multiple layers on the substrate.

[0081] When manufacturing an optical laminate 10 using a roll-to-roll optical laminate manufacturing apparatus 20, the conveying speed (linear speed) of the optical laminate 10 during manufacturing can be appropriately set. For example, the conveying speed is preferably 0.5 m / min or more and 20 m / min or less, and more preferably 0.5 m / min or more and 10 m / min or less.

[0082] <Winding and Unwinding Device>

[0083] The winding and unwinding device 4 includes: a chamber 34 internally configured with a predetermined reduced-pressure atmosphere, and one or more vacuum pumps 21 for venting gas from the chamber 34 to create a reduced-pressure atmosphere. Figure 3 (One of them) and the unwinding roller 23 and guide roller 22 disposed in the chamber 34. Figure 3 As shown, chamber 34 is connected to chamber 31 of sputtering device 1.

[0084] A transparent substrate 11 is wound on an unwinding roller 23. The unwinding roller 23 feeds the transparent substrate 11 to the sputtering device 1 at a specified conveying speed.

[0085] <Sputtering device>

[0086] Figure 3 The sputtering apparatus 1 shown includes: a chamber 31 internally configured with a predetermined reduced-pressure atmosphere, and one or more vacuum pumps 21 for venting gas from the chamber 31 to create a reduced-pressure atmosphere. Figure 3 (Two in the middle), film forming rollers 25, multiple (in) Figure 3 (Two in the middle) guide rollers 22, multiple (in Figure 4 In the example shown, there are three film-forming parts 41 (41A, 41B, 41C) and a defect detection part 42.

[0087] like Figure 3 As shown, the film-forming roller 25, guide roller 22, film-forming section 41, and defect detection section 42 are disposed in the chamber 31. The chamber 31 is connected to the chamber 34 of the winding and unwinding device 4.

[0088] The film forming roller 25 and the guide roller 22 convey the transparent substrate 11 from the unwinding device 4 at a specified conveying speed, and supply the transparent substrate 11, on one side 11a of the transparent substrate 11, with the optical functional layer 12 formed thereon, to the surface treatment device 2.

[0089] exist Figure 3In the sputtering apparatus 1 shown, a high refractive index layer 12a is formed on one side 11a of a transparent substrate 11 traveling on a film-forming roller 25 by a film-forming section 41A, and a low refractive index layer 12b is formed on it by a film-forming section 41B, thereby forming an optical functional layer 12. Then, a defect detection section 42 is used to inspect the optical functional layer 12 for defects. If a defect is found in the optical functional layer 12, a marking layer 13 is formed at the defect location D by a film-forming section 41C (see reference). Figure 1 , 2 ).

[0090] Film-forming part 41 Figure 3 As shown, multiple film-forming sections 41 are arranged opposite each other at predetermined intervals from the outer peripheral surface of the film-forming roller 25, surrounding the film-forming roller 25. The number of film-forming sections 41 is simply the sum of the total number of layers of high refractive index layer 12a and low refractive index layer 12b forming the optical functional layer 12 and the number of marking layers 13 formed.

[0091] In cases where the total number of layers of the high refractive index layer 12a and the low refractive index layer 12b forming the optical functional layer 12 is large, making it difficult to ensure the distance between adjacent film-forming sections 41, multiple film-forming rollers 25 may be provided in the chamber 31, and film-forming sections 41 may be provided around each film-forming roller 25.

[0092] When multiple film-forming rollers 25 are provided, guide rollers 22 may also be provided as needed. Multiple chambers 31 equipped with film-forming rollers 25 and film-forming sections 41 may also be connected. In addition, the diameter of the film-forming rollers 25 may be appropriately changed in order to easily ensure the distance between adjacent film-forming sections 41.

[0093] Each film-forming section 41 is provided with a predetermined target (not shown). A voltage is applied to the target using a known structure. In this embodiment, a gas supply section (not shown) that supplies a predetermined reactive gas and a carrier gas to the target at a predetermined flow rate, and a known magnetic field generating source (not shown) that forms a magnetic field on the surface of the target are provided near the target.

[0094] The material of the target, as well as the type and flow rate of the reactive gas, are appropriately determined based on the composition of the high refractive index layer 12a, the low refractive index layer 12b, and the marking layer 13 formed on the transparent substrate 11 by passing between the film-forming section 41 and the film-forming roller 25.

[0095] For example, when forming a high-refractive-index layer 12a of Nb₂O₅ using film-forming section 41A, Nb is used as the target and O₂ is used as the reactive gas. Similarly, when forming a low-refractive-index layer 12b of SiO₂ using film-forming section 41B, Si is used as the target and O₂ is used as the reactive gas. Furthermore, when forming a Ge layer as a marker layer 13 at the defect site D using film-forming section 41C, Ge is used as the target and Ar is used as the carrier gas.

[0096] In this embodiment, from the viewpoint of increasing the film formation speed, magnetron sputtering is preferred as the sputtering method.

[0097] It should be noted that sputtering is not limited to magnetron sputtering; other methods include two-electrode sputtering that utilizes plasma generated by DC glow discharge or high frequency, and three-electrode sputtering with an additional hot cathode.

[0098] The defect detection unit 42 is simply an optical monitor that detects defects in the optical functional layer 12 when defects exist after each layer of the optical functional layer 12 has been formed. This allows for confirmation of the presence or absence of defects in the formed optical functional layer 12. Examples of defects that may occur in the optical functional layer 12 include: portions where optical properties do not meet desired values, foreign matter, pinholes, etc. These defects can be detected by the optical monitor.

[0099] As an optical monitor constituting the defect detection unit 42, an example of such an optical monitor is one that measures changes in optical properties, such as reflectivity, along the width direction of the optical functional layer 12 formed on one side 11a of the optical laminate 10 using an optical head, thereby detecting the defect location D. The optical head can scan the optical laminate 10 in a width direction perpendicular to its extension direction. Upon detecting the defect location D, the defect detection unit 42 outputs the position information of the defect location D to a control unit (not shown).

[0100] The control unit (not shown) controls the film formation direction based on the input location information of the defect site D. Then, the film formation unit 41C forms a marking layer 13 made of semiconductor, which is germanium in this embodiment, in a manner that overlaps with the defect site D.

[0101] Surface treatment apparatus

[0102] Figure 3 The surface treatment apparatus 2 shown includes: a chamber 32 with a predetermined reduced pressure atmosphere inside, a can-shaped roller 26, and multiple (in) Figure 3 The middle section contains two guide rollers 22 and a plasma discharge device 43. (For example...) Figure 3As shown, the can-shaped roller 26, the guide roller 22, and the plasma discharge device 43 are disposed within the chamber 32. Figure 3 As shown, chamber 32 is connected to chamber 35 of the winding device 5.

[0103] The can-shaped roller 26 and the guide roller 22 convey the transparent substrate 11, which is fed from the sputtering device 1 and has formed an optical functional layer 12 and a marking layer 13 with defective parts D, at a specified conveying speed, and deliver the optical laminate 10 with the surface treated of the optical functional layer 12 to the winding device 5.

[0104] Plasma discharge device 43 is a type of corona discharge device, such as... Figure 3 As shown, the can-shaped roller 26 is positioned opposite to the outer peripheral surface at a predetermined interval. The plasma discharge device 43 ionizes the gas through glow discharge. Preferably, the gas is inexpensive and does not affect optical properties; for example, argon, oxygen, nitrogen, helium, etc. Argon is preferred because it has a large mass, is chemically stable, and is readily available.

[0105] In this embodiment, as the plasma discharge device 43, a glow discharge device that ionizes argon gas by passing it through a high-frequency plasma is preferably used.

[0106] When the surface treatment of the optical functional layer 12 is performed by plasma discharge (corona discharge) using such a plasma discharge device 43, the marking layer 13 formed in the presence of defect sites D is made of a semiconductor material such as a germanium film, so the plasma discharge will not abnormally discharge to the marking layer 13. The marking layer 13 is formed of a semiconductor material, so its conductivity is low, which can prevent abnormal plasma discharge from occurring to the marking layer 13.

[0107] <Winding device>

[0108] Figure 3 The winding device 5 shown includes: a chamber 35 internally configured with a predetermined reduced-pressure atmosphere, and one or more vacuum pumps 21 for venting gas from the chamber 35 to create a reduced-pressure atmosphere. Figure 3 (One of them) and a take-up roller 24 and a guide roller 22 disposed in the chamber 35.

[0109] An optical laminate 10 is wound on a take-up roller 24. The take-up roller 24 and the guide roller 22 take up the optical laminate 10 at a specified take-up speed.

[0110] As Figure 3The vacuum pumps 21 included in the optical laminate manufacturing apparatus 20 shown can be, for example, dry pumps, oil rotary pumps, turbomolecular pumps, oil diffusion pumps, cryogenic pumps, sputtering ion pumps, and suction pumps. The vacuum pumps 21 can be appropriately selected or combined in each of the chambers 31, 32, 34, and 35 to achieve the desired depressurization state.

[0111] Next, regarding the use Figure 3 The optical laminate manufacturing apparatus 20 shown describes a method for continuously performing optical functional layer formation, defect inspection, defect area display, and surface treatment processes while maintaining the optical laminate 10 under reduced pressure during manufacturing.

[0112] First, an unwinding roller 23 with a transparent substrate 11 wound on it is placed in the chamber 34 of the unwinding device 4. Then, the unwinding roller 23 and the guide roller 22 are rotated to deliver the transparent substrate 11 to the sputtering device 1 at a specified conveying speed.

[0113] Next, an optical functional layer formation process, a defect inspection process, and a defect area display process as needed are performed in the chamber 31 of the sputtering apparatus 1. Specifically, the film-forming roller 25 and the guide roller 22 are rotated, and while the transparent substrate 11 is conveyed at a specified conveying speed, an optical functional layer 12 is formed on one side 11a of the transparent substrate 11 traveling on the film-forming roller 25.

[0114] In this embodiment, a high refractive index layer 12a obtained through film-forming portion 41A and a low refractive index layer 12b obtained through film-forming portion 41B are alternately stacked. Thus, for example, an optical functional layer 12 as an anti-reflective layer is formed.

[0115] The sputtering pressure during the formation of the optical functional layer 12 varies depending on the sputtered metal, and can be 2 Pa or less, preferably 1 Pa or less, more preferably 0.6 Pa or less, and particularly preferably 0.2 Pa or less. If the sputtering pressure is at a reduced pressure of 1 Pa or less, the mean free path of the film-forming molecules becomes longer, and they are stacked in a high-energy state, thus forming a denser and better film.

[0116] Next, the formed optical functional layer 12 is scanned by the defect detection unit 42, such as an optical monitor, to detect whether there are any defects in the optical functional layer 12 (defect inspection process). Then, if a defective part D is found in the optical functional layer 12, the defect detection unit 42 outputs the location information of the defective part D to the control unit (not shown).

[0117] Next, in the film forming section 41C, based on the position information of the defect region D input to the control section (not shown), a marking layer 13 made of semiconductor, which is germanium in this embodiment, is formed in a manner that overlaps with the defect region D (defect region display process).

[0118] Next, the optical functional layer 12 is subjected to a surface treatment process within the chamber 32 of the surface treatment apparatus 2. In this embodiment, the transparent substrate 11 with the optical functional layer 12 formed thereon, obtained through the optical functional layer forming process, is kept out of contact with the atmosphere, and the surface treatment process is performed continuously under reduced pressure.

[0119] In the surface treatment process, the can-shaped roller 26 and the guide roller 22 are rotated, and while conveying the transparent substrate 11 on which the optical functional layer 12 is formed at a specified conveying speed, a discharge treatment is performed on the surface of the optical functional layer 12 that is traveling on the can-shaped roller 26. This surface treatment process is performed, for example, after the manufacture of the optical laminate 10, as a cleaning process to improve adhesion when, for example, a protective film is applied to the surface of the optical functional layer 12 or when other layers are further formed by overlapping with the optical functional layer 12. Examples of layers further formed by overlapping with the optical functional layer 12 include, for example, antifouling layers formed by vapor deposition using fluorinated compounds or organosilicon compounds.

[0120] Surface treatment methods for the optical functional layer 12 can include glow discharge treatment, plasma treatment, ion etching, and alkaline treatment. Among these, glow discharge treatment is preferred because it allows for large-area processing.

[0121] When the surface of the optical functional layer 12 is subjected to a discharge process, the surface of the optical functional layer 12 is etched, and the surface roughness of the optical functional layer 12 changes. The surface roughness Ra of the optical functional layer 12 can be controlled by setting the cumulative output during the discharge process to an appropriate range.

[0122] In this surface treatment process, when the optical functional layer 12 is surface-treated by discharge, the marking layer 13 formed in the presence of defect site D is made of a semiconductor material such as a germanium film, so there is no abnormal discharge to the marking layer 13. The marking layer 13 is formed of a semiconductor material, so it has low conductivity, which can prevent abnormal discharge to the marking layer 13 and further defects from being generated in the optical functional layer 12.

[0123] Using the above method, an optical laminate 10 having an optical functional layer 12 formed by sputtering can be obtained. Then, by rotating the guide roller 22, the optical laminate 10 is fed to the winding device 5.

[0124] Then, within the chamber 35 of the winding device 5, the optical laminate 10 is wound onto the winding roller 24 by the rotation of the winding roller 24 and the guide roller 22.

[0125] In the optical laminate 10 thus obtained, if there is a defect in the optical functional layer 12, a marking layer 13 is formed overlapping the defect site D. This marking layer is a semiconductor, such as a germanium film, and can therefore be easily detected using visible light. Therefore, in subsequent processes, when avoiding the defect site D and using the optical laminate 10, the defect site D can be easily identified visually using a simple detector employing visible light.

[0126] It should be noted that the surface treatment process may not be as described above. Figure 3 The process shown is continuous with the formation of the optical functional layer. For example, it may continue until the optical functional layer 12 is formed and temporarily rolled up, and then a protective film is applied based on the surface treatment process performed elsewhere, or other functional layers may be formed on the optical functional layer 12.

[0127] It should be noted that in the optical laminate 10 of this embodiment, various layers may be provided on the side of the transparent substrate 11 opposite to the side 11a where the optical functional layer 12 is formed, as needed. For example, an adhesive layer for bonding with other components may also be provided. In addition, other optical films may be provided through the adhesive layer. Examples of other optical films include polarizing films, phase difference compensation films, and films that function as half-wavelength plates or quarter-wavelength plates.

[0128] In addition, a layer with functions such as anti-reflection, selective reflection, anti-glare, polarization, phase difference compensation, field of view compensation or expansion, light guiding, diffusion, brightness enhancement, hue adjustment, and conductivity can also be directly formed on the other side of the transparent substrate.

[0129] It should be noted that the shape of the optical laminate 10 can be a smooth shape or a nanoscale uneven structure with a moth-eye effect to provide anti-glare functionality. Furthermore, it can also be a micrometer- to millimeter-scale geometric shape such as a lens or prism. The shape can be formed, for example, through a combination of photolithography and etching, shape transfer, hot pressing, etc. In this embodiment, the film is formed by vapor deposition, etc., so even if the substrate has an uneven shape, the uneven shape can be maintained.

[0130] The optical laminate 10 of this embodiment can be used as an anti-reflective film on the display surface of an image display unit such as a liquid crystal display panel or an organic EL display panel. In addition, the optical laminate 10 can also be applied to surfaces such as window glass, goggles, the light-receiving surface of solar cells, smartphone screens, personal computer monitors, information input terminals, tablet terminals, AR (Augmented Reality) devices, VR (Virtual Reality) devices, electro-optical display panels, glass table surfaces, game consoles, aircraft, trains, and other operational support devices, navigation systems, instrument panels, and optical sensor surfaces.

[0131] The embodiments of the present invention have been described above, but these embodiments are provided as examples and are not intended to limit the scope of the invention. These embodiments can be implemented in various other ways, and various omissions, substitutions, and modifications can be made without departing from the spirit of the invention. These embodiments or variations thereof are included in the scope and spirit of the invention, and are also included in the scope of the invention as described in the claims and its equivalents.

[0132] Example

[0133] First, a transparent substrate consisting of a cellulose triacetate (TAC) film with a thickness of 80 μm was prepared. Then, a 5 μm thick hard coating consisting of a UV-curable resin composition was formed on the transparent substrate. Next, an optical functional layer (anti-reflective layer) was formed on the hard coating using a mixture of Ar and O2 gases as sputtering targets, employing both Si and Nb targets. Specifically, the optical functional layer was formed by sequentially and repeatedly depositing a low-refractive-index layer (first layer) of SiO2, a high-refractive-index layer (second layer) of Nb2O5, a low-refractive-index layer (third layer) of SiO2, a high-refractive-index layer (fourth layer) of Nb2O5, and a low-refractive-index layer (fifth layer) of SiO2 on the hard coating.

[0134] Next, Ge (Example 1), FeSi (Fe 10%) (Example 2), Cu (Comparative Example 1), Ag (Comparative Example 2), and Cr (Comparative Example 3) were used as sputtering targets, and DC sputtering was performed at an output of 5W / cm². 2 Thin films of each embodiment (marker layer) and comparative example (metal film) were formed under argon atmosphere with a film thickness of 20 nm, overlapping with the optical functional layer.

[0135] The following tests were conducted using the optical laminates (samples) of Examples 1 and 2 and Comparative Examples 1 to 3 obtained in this way.

[0136] (1) Abnormal discharge test during corona treatment

[0137] Corona treatment device: CORONA STATION (manufactured by Kasuga Electric Co., Ltd.), high-frequency power supply: AGF-012 (manufactured by Kasuga Electric Co., Ltd.).

[0138] Output setting: 10.

[0139] Table speed: 20.

[0140] Under the above conditions, visually check for abnormal discharge.

[0141] (2) Measurement of surface resistance values of the marking layer (Example), metal film (Comparative Example)

[0142] Surface resistance measuring instrument: Loresta GX (manufactured by Nittoseiko Analytech Co., Ltd.).

[0143] (3) Detection test of the marking layer (Example), metal film (Comparative Example)

[0144] (3-1: Detection test 1) Use the following measuring device to determine whether a marking layer composed of a semiconductor can be detected. The measuring device includes: a measuring unit that irradiates light on the film and measures the light transmitted or reflected by the film; and a moving mechanism that can move the measuring unit along a first direction intersecting the conveying direction of the film. The measuring unit has: a light projecting unit that irradiates light on the film; and an integrating sphere that condenses the light from the film. The measurement is performed 10 times. All cases where detection is possible are set as qualified, and cases where detection is poor are set as unqualified.

[0145] (3-2: Detection test 2) Visually confirm the marking layer under visible light. A case where the difference between the marking layer and its peripheral part is easily recognizable is set as qualified, and a case where it is difficult to recognize is set as unqualified.

[0146] (4) Measurement of reflectance of the marking layer (Example), metal film (Comparative Example)

[0147] Spectrophotometer: U3900 (manufactured by Hitachi High-Tech Science Co., Ltd.).

[0148] Show the test results of (1)-(3) in Table 1. In addition, show the test result of (4) in Figure 4

[0151] .

[0149] [Table 1]

[0150] According to the results shown in Table 1, in the abnormal discharge test, the optical laminates with a marking layer formed using semiconductors (Examples 1 and 2) did not produce abnormal discharge even after corona treatment. On the other hand, the optical laminates with metal films formed (Comparative Examples 1 to 3) all produced abnormal discharge, resulting in damage to the optical functional layers.

[0152] Furthermore, in the testing, the metal film of Comparative Example 1 was difficult to detect. Therefore, it can be confirmed that Examples 1 and 2, which used a semiconductor film as a marker layer, satisfy both the requirements for preventing abnormal discharge and ease of detection.

[0153] On the other hand, according to Figure 4 The results show that Examples 1 and 2, which used semiconductor films as marker layers, exhibited minimal variation in reflectivity across the entire region above 370 nm and below 790 nm.

[0154] Explanation of reference numerals in the attached figures

[0155] 1: Sputtering device; 4: Unwinding device; 5: Winding device; 10: Optical laminate; 11: Transparent substrate; 12: Optical functional layer; 12a: High refractive index layer; 12b: Low refractive index layer; 13: Marking layer; 20: Manufacturing device; 21: Vacuum pump; 22: Guide roller; 23: Unwinding roller; 24: Winding roller; 25: Film forming roller; 26: Can roller; 31, 32, 34, 35: Chambers; 41, 41A, 41B, 41C: Film forming section; 42: Defect detection section; 43: Plasma discharge device.

Claims

1. An optical laminate, characterized by, An optical laminate in which an optical functional layer is stacked on a substrate, wherein The optical functional layer contains an inorganic oxide or an inorganic nitride, A mark layer is formed locally on a surface of the optical functional layer, The mark layer is composed of a semiconductor material, and has a reflectance of 40% or more for light in a wavelength range of 400 nm or more and 700 nm or less, The mark layer is formed so as to overlap at least a part of a defective site of the optical functional layer, The mark layer contains germanium or silicon.

2. The optical laminate according to claim 1, wherein The mark layer is a sputtered film formed by sputtering.

3. The optical laminate according to claim 1 or 2, wherein The optical laminate is an antireflection film, The optical functional layer is composed of a laminate in which a low-refractive-index layer and a high-refractive-index layer are alternately stacked.

4. A method for manufacturing an optical laminate, characterized by A method of manufacturing the optical laminate according to any one of claims 1 to 3, comprising: an optical functional layer forming step of forming the optical functional layer on the substrate; a defect inspection step of inspecting defects of the optical functional layer; and a defect region display step of forming the mark layer on a region including a defect when a defect is detected in the defect inspection step.

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