Method and device for measuring height of uneven portion, and method and device for manufacturing resin film

Abstract

To provide a measurement method capable of simply measuring a height of an uneven part of a long film.SOLUTION: A method for measuring a height of an uneven part formed in a long film includes a step (i) of vertically irradiating the long film with parallel light, a step (ii) of photographing the parallel light permeating through the long film, and acquiring an image, and a step (iii) of measuring the height of the uneven part on the basis of the image, wherein the step (iii) includes a step (iii-1) of measuring an area of an area where the parallel light cannot linearly permeate through the long film from the image, and a step (iii-2) of calculating the height of the uneven part from the area.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a method and an apparatus for measuring the height of uneven portions formed on a long film, and to a method and an apparatus for manufacturing a long film having uneven portions with height-controlled. [Background technology]

[0002] Conventionally, unevenness may be formed on the surface of a film as described in Patent Documents 1 and 2. For example, unevenness may be formed on the end portions in the width direction of a long thin film in order to improve the handleability of the film. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2011-214836 A [Patent Document 2] JP 2017-203641 A Summary of the Invention [Problem to be solved by the invention]

[0004] The uneven portion is preferably formed while controlling its height. In order to control the height, it is required to measure the height of the uneven portion. However, in the past, the height of the uneven portion was required to be measured using a measuring device such as a microscope or a three-dimensional surface profiler while the long film was stationary, and it was not possible to easily measure it on the production line.

[0005] The present invention has been devised in consideration of the above-mentioned problems, and aims to provide a measurement method and measurement device that can easily measure the height of the uneven portions of a long film, and a manufacturing method and manufacturing device that can manufacture a long film while controlling the height of the uneven portions. [Means for solving the problem]

[0006] The present inventors have conducted intensive research to solve the above-mentioned problems, and as a result, the present inventors have found that in a measurement method including the steps of irradiating a long film with parallel light perpendicularly, photographing the parallel light transmitted through the long film to obtain an image, and measuring the height of the unevenness based on the image, the height of the unevenness of the long film can be easily measured by measuring, from the image, the area of ​​an area where the parallel light was unable to transmit straight through the long film, and calculating the height of the unevenness from the area, and have completed the present invention. That is, the present invention includes the following.

[0007] [1] A method for measuring the height of unevenness formed on a long film, comprising: A step (i) of vertically irradiating the long film with parallel light; (ii) capturing an image of the parallel light transmitted through the long film; (iii) measuring the height of the uneven portion based on the image; The step (iii) A step (iii-1) of measuring an area of ​​an area where the parallel light was not able to pass straight through the long film from the image; A step (iii-2) of calculating the height of the uneven portion from the area; A measurement method including: [2] The measurement method according to [1], wherein the uneven portion is formed on an end portion in the width direction of the film and aligned in the longitudinal direction of the film. [3] The measurement method according to [1] or [2], wherein the step (iii-1) includes measuring the area of ​​the area in which the parallel light cannot pass straight through the long film, using an area set by dividing at least the film in the longitudinal direction as one unit. [4] The measurement method according to any one of [1] to [3], wherein the step (iii-1) includes measuring the area of ​​the area in which the parallel light cannot pass straight through the long film, with a region set by dividing the film in both the longitudinal direction and the width direction as one unit. [5] The measurement method according to any one of [1] to [4], wherein the step (ii) includes photographing the parallel light transmitted through the long film by a camera provided on the opposite side of the long film to the side on which the parallel light is irradiated. [6] The measurement method according to [5], wherein the camera is a line scan camera. [7] The measurement method according to any one of [1] to [6], wherein the step (ii) includes photographing the parallel light transmitted through the long film after it has further passed through a telecentric lens. [8] A method for producing a long film having an uneven portion, comprising: The manufacturing method comprises: A step (I) of forming a concave-convex portion on a resin film to obtain the long film; and a step (II) of controlling the height of the uneven portion formed in the step (I); The step (II) A step (II-1) of vertically irradiating the long film with parallel light; A step (II-2) of photographing the parallel light transmitted through the long film to obtain an image; A step (II-3) of measuring an area of ​​an area where the parallel light was not able to pass straight through the long film from the image; and (II-4) controlling conditions for forming the concave-convex portion in the step (I) based on the area of ​​the area. [9] The method for producing a long film according to [8], wherein the step (II-4) includes controlling conditions for forming the uneven portion in the step (I) so that the area of ​​the area falls within a predetermined range.

[10] The step (II-3) includes measuring the area of ​​the area in which the parallel light cannot pass straight through the long film, with a region set at least in a longitudinal direction of the film as one unit, The method for producing a long film described in [8] or [9], wherein the step (II-4) includes controlling the conditions for forming the uneven portion in the step (I) so that the area of ​​the area measured in one unit falls within a predetermined range.

[11] The step (II-3) includes measuring the area of ​​the area in which the parallel light cannot pass straight through the long film, with each area set in both the film longitudinal direction and the film width direction as a unit, The method for producing a long film described in any one of [8] to

[10] , wherein the step (II-4) includes controlling the conditions for forming the uneven portion in the step (I) so that the area of ​​the area measured in one unit falls within a predetermined range.

[12] The step (I) includes forming the concave-convex portions at different positions in the longitudinal direction of the film using a plurality of processing devices, The method for producing a long film described in any one of [8] to

[11] , wherein the step (II-4) includes controlling the conditions for forming the uneven portion in the step (I) so that the areas corresponding to the uneven portions formed by the multiple processing devices fall within the same range.

[13] The method for producing a long film according to any one of [8] to

[12] , further comprising a step (III) of calculating a height of the uneven portion from the area of ​​the area measured in the step (II-3).

[14] The method for producing a long film according to any one of [8] to

[13] , wherein the height of the concave and convex portions is 1 μm or more and 25 μm or less.

[15] The method for producing a long film according to any one of [8] to

[14] , wherein the step (I) includes forming the uneven portion by processing using laser light or heat.

[16] The method for producing a long film according to any one of [8] to

[15] , wherein the step (I) includes forming a plurality of the concave-convex portions at the ends of the film in the width direction, side by side in the longitudinal direction of the film.

[17] The method for producing a long film described in any one of [8] to

[16] , wherein the step (II-2) includes photographing the parallel light transmitted through the long film with a camera installed on the opposite side of the long film from the side on which the parallel light is irradiated.

[18] The method for producing a long film according to

[17] , wherein the camera is a line scan camera.

[19] The method for producing a long film according to any one of [8] to

[18] , wherein the step (II-2) includes photographing the parallel light transmitted through the long film after it has further passed through a telecentric lens.

[20] An apparatus for measuring the height of unevenness formed on a long film, comprising: An irradiation unit capable of irradiating the long film with parallel light; an imaging unit capable of capturing an image by capturing the parallel light transmitted through the long film; a height measuring unit capable of measuring the height of the uneven portion based on the image; The height measuring unit is an area measuring unit capable of measuring an area of ​​an area where the parallel light was not able to pass straight through the long film from the image; a height calculation unit capable of calculating a height of the uneven portion from the area; A measuring device comprising:

[21] An apparatus for producing a long film having a concave-convex portion, comprising: The manufacturing apparatus comprises: a concave-convex forming unit capable of forming a concave-convex portion on a resin film to obtain the long film; a height control unit capable of controlling the height of the uneven portion formed by the unevenness forming unit; The height control section, An irradiation unit capable of irradiating the long film with parallel light; an imaging unit capable of capturing an image by capturing the parallel light transmitted through the long film; an area measuring unit capable of measuring an area of ​​an area where the parallel light was not able to pass straight through the long film from the image; a condition control unit capable of controlling conditions for forming the uneven portion in the unevenness forming unit based on the surface area of ​​the area. Effect of the Invention

[0008] According to the present invention, it is possible to provide a measurement method and a measurement device that can easily measure the height of the uneven portions of a long film, and a manufacturing method and a manufacturing device that can manufacture a long film while controlling the height of the uneven portions. [Brief description of the drawings]

[0009] [Figure 1] FIG. 1 is a plan view showing a schematic view of a long film according to one embodiment of the present invention, as viewed in the thickness direction of the long film. [Diagram 2] FIG. 2 is a cross-sectional view that typically shows a cross section of the projections and recesses of a long film according to one embodiment of the present invention, cut along a plane parallel to the thickness direction. [Diagram 3] FIG. 3 is a plan view that shows a schematic planar shape of one of the concave and convex portions of a long film according to one embodiment of the present invention, as viewed from the thickness direction of the long film. [Figure 4] FIG. 4 is an enlarged schematic plan view of one of the corners of the projections and recesses of a long film according to one embodiment of the present invention. [Diagram 5] FIG. 5 is a plan view that shows a schematic view of the movement of an irradiation point P of the laser light that is irradiated to form the corner portion. [Figure 6] FIG. 6 is a plan view that shows a schematic view of the movement of an irradiation point P of a laser beam that is irradiated to form a straight line portion. [Figure 7] FIG. 7 is a front view illustrating a schematic diagram of the measurement device according to the first embodiment of the present invention. [Figure 8] FIG. 8 is a front view showing a schematic diagram of a telecentric lens and a diaphragm provided at the focal position of the telecentric lens. [Figure 9] FIG. 9 is a front view that illustrates a schematic diagram of a telecentric lens and a diaphragm provided at the focal position of the telecentric lens. [Figure 10] FIG. 10 is an enlarged plan view showing a schematic view of the vicinity of an end portion in the film width direction TD of a long film that is the subject of measurement by the measurement method according to the first embodiment of the present invention. [Figure 11] FIG. 11 is a front view showing a schematic diagram of a measuring device according to a second embodiment of the present invention. [Figure 12] FIG. 12 is an enlarged schematic plan view showing the vicinity of an end portion in the film width direction TD of a long film that is the subject of measurement by a measurement method according to a second embodiment of the present invention. [Figure 13] FIG. 13 is a front view that illustrates a manufacturing apparatus according to a third embodiment of the present invention. [Figure 14] FIG. 14 is a front view diagrammatically showing a manufacturing apparatus according to a fourth embodiment of the present invention. [Figure 15] FIG. 15 is a front view diagrammatically showing a manufacturing apparatus according to a fifth embodiment of the present invention. [Figure 16] FIG. 16 is an enlarged plan view showing a schematic view of the vicinity of an end portion in the film width direction TD of a long film produced by using a production apparatus according to a fifth embodiment of the present invention. [Figure 17] FIG. 17 is a schematic plan view showing the planar shape of the concave-convex portion 1 formed in Example 1. As shown in FIG. [Figure 18] FIG. 18 is a graph showing the relationship between the actual measured value of the average height of the corners of the unevenness parts measured in the examples and the average number of pixels in the shadow areas corresponding to the unevenness parts. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] The present invention will be described in detail below with reference to embodiments and examples. However, the present invention is not limited to the embodiments and examples shown below, and may be modified and implemented as desired without departing from the scope of the claims and their equivalents.

[0011] In the following description, a "long" film refers to a film having a length of 5 times or more its width, preferably 10 times or more its width, specifically a film having a length that can be wound into a roll for storage or transportation. There is no particular upper limit to the length of a long film, and it can be, for example, 100,000 times or less its width.

[0012] In the following description, the term "thickness direction" refers to the thickness direction of the film, unless otherwise specified.

[0013] In the following description, unless otherwise specified, "(meth)acrylic" is a term that includes "acrylic", "methacrylic", and combinations thereof, and "(meth)acrylate" is a term that includes "acrylate", "methacrylate", and combinations thereof.

[0014] [1. Overview of long film] Before describing a method for measuring the height of the projections and recesses of a long film and a method for manufacturing a long film having projections and recesses, a description will be given of the long film having projections and recesses. Fig. 1 is a plan view showing a long film 100 according to one embodiment of the present invention, as viewed from the thickness direction of the long film 100. As shown in Fig. 1, the long film 100 is a long film, and has an uneven portion 110 on at least one surface 110U.

[0015] Fig. 2 is a cross-sectional view showing a schematic cross section of an uneven portion 110 of a long film 100 according to one embodiment of the present invention, cut along a plane parallel to the thickness direction. As shown in Fig. 2, the uneven portion 110 is a part of the long film 100, and includes a convex portion 111 protruding from a film surface 110U surrounding the uneven portion 110. The uneven portion 110 may also include a concave portion 112 formed to be recessed further than the convex portion 111.

[0016] Usually, the uneven portion 110 is formed by a part or the whole of the resin contained in the recess 112 moving to the protrusion 111. Therefore, the uneven portion 110 usually includes a combination of the protrusion 111 and the recess 112. For example, in the uneven portion 110 formed by processing using a laser beam, the recess 112 corresponds to a portion where the resin has been removed by thermal melting or ablation caused by the irradiation of the laser beam, and the protrusion 111 corresponds to a portion where the resin heated and fluidized by the irradiation of the laser beam rises. Therefore, the uneven portion 110 formed by processing using a laser beam may include the recess 112 and the protrusions 111 provided on both sides of the recess 112, as shown in FIG. 2.

[0017] Since the convex portions 111 protrude from the surrounding surface 100U of the long film 100, the substantial thickness of the long film 100 is increased at the concave-convex portions 110. This improves the handling properties of the long film 100, such as the transportability and windability.

[0018] The height H of the uneven portion 110 represents the size of the convex portion 111 of the uneven portion 110 in the thickness direction. The height H of the uneven portion 110 may be uniform or non-uniform. For example, the uneven portion 110 having a linear planar shape as described later may have different heights H at its corners and straight portions. In addition, in the uneven portion 110 having a plurality of convex portions 111 as in the example shown in FIG. 2, the height H of one convex portion 111 may differ from that of the other convex portion 111. Therefore, in the measurement method described later, when the height H of the uneven portion 110 is uniform in the area to be measured, the height H of the uneven portion 110 can be measured at a single value, and when the height H of the uneven portion 110 is non-uniform in the area to be measured, a representative value of the height H of the uneven portion 110 can be measured. Examples of the representative value include a maximum height and an average height. In the following description, the height of the object measured by the measurement method according to this embodiment, such as the representative value, may be particularly referred to as a "representative height".

[0019] The specific range of the height H of the uneven portion 110 is usually 1 μm or more, preferably 2 μm or more, particularly preferably 3 μm or more, and usually 25 μm or less, preferably 20 μm or less, more preferably 15 μm or less. When the height H of the uneven portion 110 is non-uniform, it is preferable that the actual measured value of the representative height (the representative value of the height described above, etc.) to be measured by the measurement method described later is within the above range. The uneven portion 110 whose actual measured value of the height H is within the above range, measured using a measuring device such as a microscope or a three-dimensional surface profiler, can be easily measured with high accuracy by the measurement method described later.

[0020] The width W of the uneven portion 110 is preferably 0.1 μm or more, more preferably 0.15 μm or more, particularly preferably 0.2 μm or more, and is preferably 1 μm or less, more preferably 0.75 μm or less, particularly preferably 0.5 μm or less. When the width W of the uneven portion 110 is equal to or greater than the lower limit of the above range, the handleability of the long film 100 can be effectively improved. Furthermore, when the uneven portion 110 has the above width W, the measurement of the representative height by the measurement method described below can be performed with particularly high accuracy.

[0021] FIG. 3 is a plan view showing a schematic planar shape of one of the concave-convex portions 110 of the long film 100 according to one embodiment of the present invention, as viewed from the thickness direction of the long film 100. There is no particular limitation on the planar shape of the concave-convex portion 110, but from the viewpoint of effectively improving the handleability of the long film 100 by the concave-convex portion 110, it is preferable to form the concave-convex portion 110 so as to have a continuous linear planar shape. Unless otherwise specified, the "planar shape" refers to the shape as viewed from the thickness direction. For example, when the concave-convex portion 110 is formed by processing using laser light, the linear concave-convex portion 110 can be formed as a continuous line in a single stroke as a trace of the movement of the irradiation point of the laser light. When the concave-convex portion 110 is formed to have a continuous linear planar shape in this way, the cross section cut along a plane II perpendicular to the extension direction of the concave-convex portion 110 is usually as shown in FIG. 2 described above. In this embodiment, as shown in Fig. 3, an example will be described in which the uneven portion 110 is formed in a continuous line when viewed in the thickness direction, and the continuous linear uneven portion 110 forms a closed ring shape as a whole. The entire uneven portion 110 formed in a single continuous line in this manner may be referred to as a "knurl portion" 120 hereinafter.

[0022] The planar shape of the linear uneven portion 110 may include straight lines, curved lines, and combinations thereof, but preferably includes a corner 130. In addition, one knurl portion 120 formed by the continuous linear uneven portion 110 may include only one corner 130, but preferably includes multiple corners 130. Usually, the height of the linearly formed uneven portion 110 tends to be higher at the corner 130. Therefore, when a planar shape including the corner 130 is adopted, the uneven portion 110 can be made higher at the corner 130, so that the handling properties such as transportability and windability of the long film 100 can be particularly improved. In this embodiment, an example will be described in which the knurl portion 120 has a planar shape including multiple straight portions 140 formed by the linearly extending uneven portion 110 and multiple corners 130 where the straight portions 140 intersect.

[0023] 4 is an enlarged schematic plan view of one of the corners 130 of the uneven portion 110 of the long film 100 according to one embodiment of the present invention. The corner 130 is sharp when viewed macroscopically, but may be rounded when viewed microscopically as shown in FIG. 4. In this case, the radius of curvature R of the rounded portion is sometimes referred to as the radius of curvature of the corner 130. From the viewpoint of increasing the height of the uneven portion 110 at the corner 130, it is preferable that the radius of curvature R of the corner 130 is small. Specifically, the radius of curvature R of the corner 130 is preferably 0.3 mm or less, more preferably 0.2 mm or less.

[0024] Moreover, from the viewpoint of increasing the height of the uneven portion 110 at the corner 130, it is preferable that the angle θ of the corner 130 is small. Here, the angle θ of the corner 130 may be the angle θ at which the extended lines 140a and 140b of the two straight line portions 140 that intersect at the corner 130 when viewed macroscopically intersect. Specifically, the angle θ of the corner 130 is preferably 120° or less, and more preferably 110° or less.

[0025] For example, when the uneven portion 110 is formed by processing using laser light, the height of the uneven portion 110 can be increased at the corners 130 by the following mechanism. Fig. 5 is a plan view showing a schematic diagram of the movement of the irradiation point P of the laser light irradiated to form the corner portion 130. Fig. 6 is a plan view showing a schematic diagram of the movement of the irradiation point P of the laser light irradiated to form the straight portion 140. In Figs. 5 and 6, the irradiation point P is shown moving in the directions indicated by the arrows A1 and A2. When forming a linearly continuous uneven portion 110 using a laser beam, the laser beam is usually irradiated onto the film while moving the irradiation point P of the laser beam, as shown in Figs. 5 and 6. When forming a straight portion 140, the irradiation point P moves linearly, as shown in Fig. 6. On the other hand, when forming a corner portion 130, the irradiation point P moves so as to bend at a steep angle, as shown in Fig. 5. When the irradiation point P is moved so as to bend sharply, the irradiation time of the laser beam becomes longer on the inner side of the moving direction, and the energy density of the irradiated laser beam may become larger. Therefore, the height of the uneven portion 110 may be higher at the corner portion 130.

[0026] Furthermore, for example, when the uneven portion 110 is formed by a processing treatment using heat, the height of the uneven portion 110 can be increased at the corner portion 130 by the following mechanism. When forming the linearly continuous uneven portion 110 using heat, a heated mold is usually brought into contact with the film. The resin in the film that is heated by contact with the mold can become fluid and move. However, the range in which the resin can move is restricted by the mold. At this time, inside the corner 130, the range in which the fluidized resin can move is narrowly restricted by the mold. Therefore, the resin moves significantly in the thickness direction, and the height of the uneven portion 110 can be high at the corner 130. Therefore, the corner 130 tends to be slightly higher on the inside.

[0027] 3, when the uneven portion 110 is formed in a continuous line to form the knurl portion 120, the size of the knurl portion 120 is not particularly limited. In a preferred example, the length L of each knurl portion 120 in the film width direction TD is TD is preferably 3 mm or more, more preferably 5 mm or more, particularly preferably 7 mm or more, and is preferably 20 mm or less, more preferably 17 mm or less, particularly preferably 15 mm or less. MDis preferably 0.1 mm or more, more preferably 0.5 mm or more, particularly preferably 1 mm or more, and is preferably 20 mm or less, more preferably 15 mm or less, particularly preferably 10 mm or less.

[0028] As shown in Fig. 1, a plurality of knurl portions 120 as the uneven portion 110 are usually formed in one long film 100. These plurality of knurl portions 120 are generally arranged side by side in the longitudinal direction MD of the film. Moreover, the knurl portions 120 are usually provided at least at one end of the film width direction TD, and preferably at both ends. The planar shapes of the knurl portions 120 as viewed from the thickness direction may be different, but in this embodiment, an example in which they are all the same is shown.

[0029] When the knurl portions 120 are arranged side by side in the longitudinal direction MD of the film, there is no particular restriction on the pitch of the knurl portions 120. In a preferred example, the pitch of the knurl portions 120 in the longitudinal direction MD of the film is preferably 0.5 mm or more, more preferably 1 mm or more, particularly preferably 1.5 mm or more, and is preferably 10 mm or less, more preferably 7 mm or less, particularly preferably 5 mm or less. The pitch of the knurl portions 120 may be constant or may vary.

[0030] The long film may be a film containing a resin. The long film may be a stretched film or an unstretched film. The long film may be a monolayer film having only a base layer, or a multilayer film having any layer in combination with the base layer.

[0031] The substrate layer is usually a layer formed of a resin. Therefore, the substrate layer usually contains a resin, and preferably contains only a resin. As such a resin, various resins can be used depending on the application of the long film, and examples of such resins include cyclic olefin resins and (meth)acrylic resins.

[0032] The cyclic olefin resin is a resin containing a cyclic olefin polymer. The cyclic olefin polymer has excellent mechanical properties, heat resistance, transparency, low moisture absorption, dimensional stability, and light weight.

[0033] The cyclic olefin polymer refers to a polymer whose structural unit has an alicyclic structure. The cyclic olefin polymer may be a polymer having an alicyclic structure in the main chain, a polymer having an alicyclic structure in the side chain, a polymer having an alicyclic structure in the main chain and in the side chain, or a mixture of two or more of these in any ratio. Among them, from the viewpoint of mechanical strength and heat resistance, a polymer having an alicyclic structure in the main chain is preferred.

[0034] Examples of the alicyclic structure include saturated alicyclic hydrocarbon (cycloalkane) structures and unsaturated alicyclic hydrocarbon (cycloalkene, cycloalkyne) structures. Among them, from the viewpoint of mechanical strength and heat resistance, cycloalkane structures and cycloalkene structures are preferred, and cycloalkane structures are particularly preferred.

[0035] The number of carbon atoms constituting the alicyclic structure is preferably 4 or more, more preferably 5 or more, and preferably 30 or less, more preferably 20 or less, and particularly preferably 15 or less, per one alicyclic structure. When the number of carbon atoms constituting the alicyclic structure is within this range, the mechanical strength, heat resistance, and moldability of the resin are highly balanced.

[0036] In the cyclic olefin polymer, the ratio of the structural units having an alicyclic structure is preferably 55% by weight or more, more preferably 70% by weight or more, and particularly preferably 90% by weight or more. When the ratio of the structural units having an alicyclic structure in the cyclic olefin polymer is within this range, the transparency and heat resistance are good.

[0037] Examples of the cyclic olefin polymer include norbornene-based polymers, monocyclic cyclic olefin-based polymers, cyclic conjugated diene-based polymers, vinyl alicyclic hydrocarbon-based polymers, and hydrogenated products thereof. Among these, norbornene-based polymers and hydrogenated products thereof are particularly preferred because of their good moldability.

[0038] Examples of norbornene-based polymers and their hydrogenated products include ring-opening polymers of monomers having a norbornene structure and their hydrogenated products; addition polymers of monomers having a norbornene structure and their hydrogenated products. Examples of ring-opening polymers of monomers having a norbornene structure include ring-opening homopolymers of one type of monomer having a norbornene structure, ring-opening copolymers of two or more types of monomers having a norbornene structure, and ring-opening copolymers of a monomer having a norbornene structure and other monomers that can be copolymerized therewith. Examples of addition polymers of monomers having a norbornene structure include addition homopolymers of one type of monomer having a norbornene structure, addition copolymers of two or more types of monomers having a norbornene structure, and addition copolymers of a monomer having a norbornene structure and other monomers that can be copolymerized therewith. Among these, the hydrogenated ring-opening polymers of monomers having a norbornene structure are particularly suitable from the viewpoints of moldability, heat resistance, low moisture absorption, dimensional stability, light weight, etc.

[0039] The weight average molecular weight (Mw) of the cyclic olefin polymer is preferably 10,000 or more, more preferably 15,000 or more, particularly preferably 20,000 or more, and is preferably 100,000 or less, more preferably 80,000 or less, particularly preferably 50,000 or less. When the weight average molecular weight is within the above range, the mechanical strength and moldability of the resin are highly balanced.

[0040] The molecular weight distribution (weight average molecular weight (Mw) / number average molecular weight (Mn)) of the cyclic olefin polymer is preferably 1.2 or more, more preferably 1.5 or more, particularly preferably 1.8 or more, and is preferably 3.5 or less, more preferably 3.0 or less, particularly preferably 2.7 or less. When the molecular weight distribution is at least the lower limit of the above range, the productivity of the polymer can be increased and the production costs can be reduced. On the other hand, when it is at most the upper limit, the amount of low molecular weight components is reduced, thereby suppressing relaxation during exposure to high temperatures and improving the stability of the film.

[0041] The weight average molecular weight and number average molecular weight are polyisoprene or polystyrene equivalent weight average molecular weights measured by gel permeation chromatography using cyclohexane as a solvent. However, in the above gel permeation chromatography, toluene may be used as a solvent if the sample is not soluble in cyclohexane.

[0042] The glass transition temperature of the cyclic olefin polymer is preferably 130° C. or higher, more preferably 135° C. or higher, and preferably 150° C. or lower, more preferably 145° C. or lower. When the glass transition temperature is equal to or higher than the lower limit of the above range, the durability of the film at high temperatures can be improved. When the glass transition temperature is equal to or lower than the upper limit of the above range, the film can be easily stretched.

[0043] As the cyclic olefin polymer, for example, those described in WO 2017 / 145718 can be used.

[0044] The ratio of the cyclic olefin polymer in the cyclic olefin resin is preferably 50% by weight to 100% by weight, more preferably 70% by weight to 100% by weight, and particularly preferably 90% by weight to 100% by weight. When the ratio of the polymer is within the above range, sufficient heat resistance and transparency can be obtained.

[0045] The cyclic olefin resin may contain any component other than the cyclic olefin polymer, so long as it does not significantly impair the effects of the present invention. Examples of the optional components include colorants such as pigments and dyes; fluorescent brighteners; dispersants; heat stabilizers; light stabilizers; ultraviolet absorbers; antistatic agents; antioxidants; lubricants; and the like. These may be used alone or in combination of two or more at any ratio.

[0046] The (meth)acrylic resin is a resin containing a (meth)acrylic polymer. The (meth)acrylic polymer means a polymer of acrylic acid or an acrylic acid derivative, and examples thereof include polymers and copolymers of acrylic acid, acrylic acid esters, acrylamide, acrylonitrile, methacrylic acid, and methacrylic acid esters. The (meth)acrylic polymer is strong and hard, and therefore can realize a film with high mechanical strength.

[0047] The (meth)acrylic polymer is preferably a polymer containing a structural unit having a structure obtained by polymerizing a (meth)acrylic acid ester. Examples of the (meth)acrylic acid ester include alkyl esters of (meth)acrylic acid. Among them, a compound having a structure derived from (meth)acrylic acid and an alkanol or cycloalkanol having 1 to 15 carbon atoms is preferable. Furthermore, a compound having a structure derived from (meth)acrylic acid and an alkanol having 1 to 8 carbon atoms is more preferable. By reducing the number of carbon atoms as described above, the elongation at the time of breaking of the film can be reduced.

[0048] Specific examples of acrylic esters include methyl acrylate, ethyl acrylate, n-propyl acrylate, i-propyl acrylate, n-butyl acrylate, i-butyl acrylate, sec-butyl acrylate, t-butyl acrylate, n-hexyl acrylate, cyclohexyl acrylate, n-octyl acrylate, 2-ethylhexyl acrylate, n-decyl acrylate, and n-dodecyl acrylate.

[0049] Specific examples of methacrylic acid esters include methyl methacrylate, ethyl methacrylate, n-propyl methacrylate, i-propyl methacrylate, n-butyl methacrylate, i-butyl methacrylate, sec-butyl methacrylate, t-butyl methacrylate, n-hexyl methacrylate, n-octyl methacrylate, 2-ethylhexyl methacrylate, n-decyl methacrylate, and n-dodecyl methacrylate.

[0050] Furthermore, the (meth)acrylic acid ester may have a substituent such as a hydroxyl group or a halogen atom, so long as the effect of the present invention is not significantly impaired. Examples of (meth)acrylic acid esters having such a substituent include 2-hydroxyethyl acrylate, 2-hydroxypropyl acrylate, 4-hydroxybutyl acrylate, 2-hydroxyethyl methacrylate, 2-hydroxypropyl methacrylate, 4-hydroxybutyl methacrylate, 3-chloro-2-hydroxypropyl methacrylate, and glycidyl methacrylate. These may be used alone or in combination of two or more at any ratio.

[0051] The (meth)acrylic polymer may be a polymer of only acrylic acid or an acrylic acid derivative, or may be a copolymer of acrylic acid or an acrylic acid derivative with any monomer copolymerizable therewith. Examples of the optional monomer include α,β-ethylenically unsaturated carboxylic acid ester monomers other than the above-mentioned (meth)acrylic acid esters, as well as α,β-ethylenically unsaturated carboxylic acid monomers, alkenyl aromatic monomers, conjugated diene monomers, non-conjugated diene monomers, carboxylic acid unsaturated alcohol esters, and olefin monomers. These may be used alone or in combination of two or more at any ratio.

[0052] When the (meth)acrylic polymer contains an optional monomer, the amount of structural units having a structure obtained by polymerizing the optional monomer in the (meth)acrylic polymer is preferably 50% by weight or less, more preferably 15% by weight or less, and particularly preferably 10% by weight or less.

[0053] Of these (meth)acrylic polymers, polymethacrylate is preferred, and polymethyl methacrylate is more preferred.

[0054] As the (meth)acrylic polymer, for example, those described in WO 2017 / 145718 can be used.

[0055] The ratio of the (meth)acrylic polymer in the (meth)acrylic resin is preferably 50% by weight to 100% by weight, more preferably 70% by weight to 100% by weight, and particularly preferably 90% by weight to 100% by weight. When the ratio of the polymer is within the above range, sufficient mechanical strength can be obtained.

[0056] The (meth)acrylic resin may contain any component other than the (meth)acrylic polymer, as long as the effect of the present invention is not significantly impaired. Examples of the optional components include the same examples as the optional components that the cyclic olefin resin may contain. In addition, the optional components may be used alone or in combination of two or more types in any ratio.

[0057] The substrate layer can be manufactured by molding the resin by a suitable film molding method. Examples of the film molding method include cast molding, extrusion molding, and inflation molding. Among them, the melt extrusion method that does not use a solvent can efficiently reduce the amount of residual volatile components, and is preferable from the viewpoint of global environment and working environment, and from the viewpoint of excellent manufacturing efficiency. As the melt extrusion method, the inflation method using a die may be used, but the T-die method is preferable from the viewpoint of excellent productivity and thickness accuracy.

[0058] When a multilayer film having two or more layers is used as the long film, the multilayer film preferably has a base layer and a functional layer. The functional layer may be provided on one side or both sides of the base layer. In particular, the functional layer is preferably provided on the uneven portion side of the base layer, and it is more preferable that the uneven portion is provided on the surface of the functional layer. Examples of such functional layers include an antistatic layer, a hard coat layer, an adhesion prevention layer, and an easy-adhesion layer.

[0059] The antistatic layer refers to a layer having a small surface resistance. The specific surface resistance of the antistatic layer is preferably 1.0×10 6 Ω / □ or more, preferably 1.0×10 7 Ω / □ or more, particularly preferably 1.0×108 Ω / □ or more, preferably 1.0×10 10 Ω / □ or less, more preferably 5.0×10 9 Ω / □ or less, particularly preferably 1.0×10 9 The surface resistance is Ω / □ or less. The surface resistance can be measured using a digital ultra-insulation / microcurrent meter ("DSM-8104" manufactured by HIOKI ELECTRIC CO., LTD.) in accordance with JIS K6911. Such an antistatic layer can be formed, for example, from a resin containing conductive particles such as metal oxide particles and a polymer.

[0060] The hard coat layer refers to a layer having high hardness. The specific hardness of the hard coat layer is preferably B or higher, more preferably HB or higher, and particularly preferably H or higher, in terms of JIS pencil hardness. Here, the JIS pencil hardness is the hardness of the pencil at which the surface of the layer is scratched by tilting the surface of the layer at a 45° angle with a pencil of various hardness and applying a load of 500 g from above in accordance with JIS K5600-5-4, and the layer begins to be scratched. Such a hard coat layer can be formed, for example, from a resin.

[0061] The adhesion prevention layer refers to a layer that has a rough surface and can suppress adhesion between films when the film is laminated with another film. Such an adhesion prevention layer can be formed, for example, from a resin containing a polymer and particles.

[0062] The adhesive layer is a layer that exhibits high adhesiveness when the surface of the adhesive layer is attached to another member. Such an adhesive layer can be formed, for example, from a resin containing a polymer.

[0063] Among the functional layers, the easy-adhesion layer is preferred. The easy-adhesion layer is preferably a layer containing an aqueous resin. The aqueous resin is a resin that can be prepared as a solution or dispersion using water as a medium. By applying an aqueous solution or aqueous dispersion containing an aqueous resin to the surface of the substrate layer and drying it, a layer of the aqueous resin can be formed on the surface of the substrate layer. Examples of the aqueous resin include urethane resin, polyester resin, and emulsions of each resin, and preferably include aqueous urethane resin.

[0064] As the functional layer, for example, those described in WO 2017 / 145718 can be used.

[0065] There is no particular limit to the width and thickness of the long film 100, and the width and thickness may be selected according to the intended use. The width of the long film 100 is preferably 700 mm or more, more preferably 1000 mm or more, even more preferably 1200 mm or more, and preferably 2500 mm or less, more preferably 2200 mm or less, and even more preferably 2000 mm or less. The thickness of the long film 100 is preferably 1 μm or more, more preferably 5 μm or more, even more preferably 20 μm or more, and preferably 1000 μm or less, more preferably 300 μm or less, and even more preferably 150 μm or less.

[0066] When the long film 100 is used as an optical film, it is preferable that the region without the concave-convex portion 110 has high transparency. Specifically, the total light transmittance of the long film 100 in the region without the concave-convex portion 110 is preferably 85% to 100%, more preferably 92% to 100%. The haze of the long film 100 in the above-mentioned region is preferably 0% to 5%, more preferably 0% to 3%, and particularly preferably 0% to 2%. Here, the total light transmittance can be measured in accordance with JIS K7105 using a turbidity meter "NDH-2000" manufactured by Nippon Denshoku Industries Co., Ltd. The haze can be measured using a turbidity meter "NDH2000" manufactured by Nippon Denshoku Industries Co., Ltd.

[0067] [2. First embodiment of method for measuring height of uneven portion] A first embodiment of the method for measuring the height of the projections and recesses of the long film described above will be described below. This method is a method for measuring the representative height of the projections and recesses formed on the long film, and includes a step (i) of vertically irradiating the long film with parallel light (collimated light), a step (ii) of photographing the parallel light transmitted through the long film to obtain an image, and a step (iii) of measuring the representative height of the projections and recesses based on the image. Step (iii) also includes a step (iii-1) of measuring the area of ​​the area where the parallel light could not transmit straight through the long film from the image obtained in step (ii), and a step (iii-2) of calculating the representative height of the projections and recesses from this area.

[0068] The parallel light irradiated to the long film in step (i) travels vertically on the surface of the long film in the areas other than the uneven parts, and can therefore pass straight through the long film. Here, the "straight-through" of light through the long film means that the light passes through the long film so that the incident direction of the light entering the long film coincides with the exit direction of the light passing through the long film. However, the parallel light irradiated to the long film is incident on the surface of the uneven parts at a large incident angle, causing refraction and making it impossible to pass straight through the long film. Therefore, in the image obtained in step (ii) of photographing the parallel light passing through the long film, the areas other than the uneven parts appear as relatively bright areas, and the uneven parts appear as relatively dark areas. Therefore, the area of ​​the relatively dark areas represents the area of ​​the areas where the parallel light could not pass straight through the long film, and this area corresponds to the area of ​​the uneven parts as viewed from the thickness direction. In the following description, the areas where the parallel light could not pass straight through the long film are photographed as relatively dark areas and are therefore sometimes called "shadow areas", and the areas other than the shadow areas (i.e., areas where the parallel light could pass straight through the long film) are sometimes called "bright areas". According to the inventor's study, it has been found that the area of ​​the unevenness seen from the thickness direction is proportional to the representative height of the unevenness. Therefore, in the measurement method according to this embodiment, the representative height of the unevenness is calculated from the "area of ​​the shadow area where the parallel light could not pass straight through the long film", which corresponds to the area of ​​the unevenness, to thereby measure the representative height of the unevenness. Hereinafter, the measurement method according to this embodiment will be described with reference to the drawings.

[0069] Fig. 7 is a front view showing a schematic diagram of a measuring device 200 according to a first embodiment of the present invention. As shown in Fig. 7, the measuring device 200 according to the first embodiment of the present invention is a device for measuring a representative height of an uneven portion (not shown in Fig. 7) formed on a long film 100, and includes an irradiation unit 210, an imaging unit 220, and a height measurement unit 230.

[0070] The irradiation unit 210 is provided so as to be able to irradiate the long film 100 with parallel light L. As the parallel light L, light with a wavelength that can pass through the long film 100 can be used. Since the long film 100 is usually able to pass visible light, light with a visible wavelength is used as the parallel light L. Unless otherwise specified, the visible wavelength refers to a wavelength range of 400 nm or more and 780 nm or less.

[0071] The irradiation unit 210 is provided so that the parallel light L can be irradiated perpendicularly to the long film 100. Here, the parallel light L being "perpendicular" to the long film 100 means that the traveling direction of the parallel light L is perpendicular to the main surface of the long film 100. Since the long film 100 has uneven parts (not shown in FIG. 7), the main surface of the long film 100 may have unevenness when viewed microscopically. In this case, it is preferable that the parallel light L is perpendicular to the main surface when the long film 100 is viewed macroscopically, ignoring the unevenness. The parallel light L thus irradiated is usually incident on the long film 100 in the thickness direction. In addition, the "perpendicular" of the parallel light L to the long film 100 may include an error depending on the accuracy required for measuring the representative height of the uneven parts. Specifically, the angle between the traveling direction of the parallel light L and the main surface of the long film 100 onto which the parallel light L is irradiated is preferably 85° to 90°, more preferably 87° to 90°, even more preferably 89° to 90°, and particularly preferably 90°.

[0072] The irradiation unit 210 may irradiate the parallel light L onto the entire long film 100 in the film width direction TD, or may irradiate only a part of the long film 100. Usually, the irradiation unit 210 is provided so as to irradiate the parallel light L onto at least a portion of the long film 100 that includes the concave-convex portion. Thus, when measuring the representative height of the concave-convex portion 110 provided at the end of the film width direction TD as shown in FIG. 1, the irradiation unit 210 can be provided so as to irradiate the parallel light L onto a portion of the long film 100 that includes the end of the film width direction TD.

[0073] In this embodiment, an example will be shown and explained that uses an irradiation section 210 equipped with a light source 211 capable of emitting light of a wavelength that can be transmitted through the long film 100, and a collimator lens 212 that can convert the light emitted from this light source 211 into parallel light L.

[0074] The photographing section 220 is provided so as to photograph the parallel light L transmitted through the long film 100 to obtain an image. Since the photographing section 220 photographs the parallel light L transmitted through the long film 100, the photographing section 220 normally includes a camera 221 provided on the opposite side of the long film 100 to the side on which the parallel light L is irradiated (hence, the opposite side from the irradiation section 210). As the camera 221, it is preferable to employ a line scan camera so as to be able to photograph the long film 100 being continuously transported at high speed and continuously.

[0075] The photographing unit 220 is preferably provided so that the parallel light L transmitted through the long film 100 can be photographed after it has further passed through a telecentric lens. Therefore, the photographing unit 220 is preferably provided with telecentric lenses 222 and 223. By using the telecentric lens 222, it is possible to effectively eliminate light rays that have not passed straight through the long film 100 from the parallel light L transmitted through the long film 100. Furthermore, by using the telecentric lens 223, it is possible to prevent the magnification of the image from being changed depending on the distance from the telecentric lens 223 to the camera 221. Therefore, by using the telecentric lenses 222 and 223, it is possible to improve the measurement accuracy of the representative height of the uneven portion.

[0076] The roles of the telecentric lenses 222 and 223 will be described in detail below with reference to the drawings. Figures 8 and 9 are front views that typically show the telecentric lenses 222 and 223 and the aperture 224 provided at the focal position thereof.

[0077] As shown in Figures 8 and 9, it is assumed that an aperture 224 is provided at the focal position of telecentric lenses 222 and 223 whose optical axes are arranged in parallel. In a telecentric lens, the chief ray is usually parallel to the optical axis throughout the lens. Therefore, as shown in Figure 7, parallel light L that has passed straight through the long film 100 passes through one of the telecentric lenses (hereinafter sometimes referred to as the "object-side telecentric lens") 222 that is closer to the long film 100, and can pass through the opening 224H of the aperture 224 as shown in Figure 8. However, light that has passed through the uneven parts of the long film 100 is refracted at the uneven parts and cannot pass straight through the long film 100. Such light ray L that cannot pass straight through the long film 100 B When this occurs, the light ray L B The light rays L that could not pass straight through the long film 100 cannot be collected at the aperture 224H of the diaphragm 224 and are blocked by the diaphragm 224. B Therefore, the light ray L that has passed through the uneven portion, which is a portion where the parallel light L cannot pass straight through, can be effectively eliminated. B Since this can appropriately eliminate the unevenness, it is possible to effectively darken the shadow areas corresponding to the unevenness in the image captured by the camera 221. This makes it possible to clearly distinguish between the shadow areas corresponding to the unevenness and the bright areas corresponding to the parts other than the unevenness. Therefore, it is possible to measure with high accuracy the area of ​​the unevenness as the area of ​​the shadow areas where the parallel light L was not able to pass straight through the long film 100, thereby improving the measurement accuracy of the height of the unevenness.

[0078] As shown in Fig. 8, the light that has passed through the aperture 224 passes through the other telecentric lens (hereinafter sometimes referred to as the "image side telecentric lens") 223. The light that has passed through the telecentric lens 223 becomes parallel light parallel to the optical axis of the image side telecentric lens 223, and is photographed by the camera 221 (see Fig. 7). Therefore, regardless of the distance between the image side telecentric lens 223 and the camera 221, the camera 221 can photograph at a constant magnification. Therefore, the influence of the variation in magnification due to the position of the camera 221 can be suppressed, and therefore the area of ​​the unevenness as the area of ​​the shadow area where the parallel light L could not pass straight through the long film 100 can be measured with high accuracy, and therefore the measurement accuracy of the height of the unevenness can be improved.

[0079] 7, an example will be described in which a photographing unit 220 is used that includes, in order from closest to the long film 100, an object side telecentric lens 222, an aperture 224, an image side telecentric lens 223, and a camera 221. The photographing unit 220 is also provided so as to be able to send information about an image photographed by the camera 221 to a height measuring unit 230.

[0080] The height measuring unit 230 is provided so as to be able to measure the representative height of the concave and convex portions of the long film 100 based on the image acquired by the photographing unit 220. The height measuring unit 230 includes an area measuring unit 231 and a height calculating unit 232.

[0081] The area measuring unit 231 is provided so as to take in information on the image acquired by the photographing unit 220 and measure, from the image, the area of ​​the shadow area where the parallel light L was not able to pass straight through the long film 100. As described above, the area of ​​the shadow area corresponds to the area of ​​the unevenness formed on the long film 100. Therefore, the area measuring unit 231 can obtain information on the area of ​​the unevenness.

[0082] Usually, an image is represented by a large number of pixels. Therefore, the image information captured by the area measurement unit 231 includes pixel information. The area measurement unit 231 may, for example, count the number of pixels having a luminance equal to or lower than a certain threshold, and measure the number of counted pixels as the area of ​​the shadow area. In this case, the threshold may be set to an appropriate value between the luminance of the pixels in the bright area and the luminance of the pixels in the shadow area, and may be, for example, a median value between the luminance of the brightest pixel and the luminance of the darkest pixel on the screen. In addition, the number of pixels is preferably large in order to improve accuracy, and may be, for example, 2800 dpi or more.

[0083] The area measurement unit 231 is usually set to measure the area of ​​the shadow area by using an appropriately set area as one unit. The area set as one unit for measuring the area of ​​the shadow area as described above may be referred to as a "measurement unit area" hereinafter. In the measurement method according to this embodiment, the value of the representative height of the unevenness can be measured for each measurement unit area. Therefore, the measured representative height of the unevenness can be a representative value of the height H of the unevenness included in the measurement unit area. Therefore, it is preferable to set the measurement unit area according to the range in which the representative height is desired to be measured.

[0084] FIG. 10 is an enlarged schematic plan view showing the vicinity of an end of a long film 100 in the film width direction TD, which is the measurement target of the measurement method according to the first embodiment of the present invention. In FIG. 10, the measurement unit areas 240 are shown separated from each other, but the measurement unit areas 240 may be set without any space between them. As shown in FIG. 10, it is preferable that the area measurement section 231 measures the area of ​​the shadow area by using the measurement unit area 240 set by dividing at least in the film longitudinal direction MD as one unit. The long film 100 is generally formed with the uneven portion 110 while being transported in the film longitudinal direction MD. At this time, since the forming conditions of the uneven portion 110 may change during the manufacturing process, the height H of the uneven portion 110 may not be constant in the film longitudinal direction MD. Therefore, from the viewpoint of obtaining detailed information on the height H of the uneven portion 110, it is preferable to set the measurement unit area 240 by dividing at least in the film longitudinal direction MD, and measure the representative height of the uneven portion 110 for each measurement unit area 240.

[0085] In this embodiment, an example will be described in which the long film 100 is divided in the film longitudinal direction MD to set the measurement unit regions 240 so that each measurement unit region 240 includes one knurl portion 120. Therefore, the area measurement unit 231 is provided so as to measure the area of ​​the shadow area for each measurement unit region 240 thus set and send information on the measured area to the height calculation unit 232.

[0086] The height calculation unit 232 is provided so as to take in information on the area of ​​the shadow area measured by the area measurement unit 231 and calculate the representative height of the unevenness of the long film 100 from that area. It has been experimentally confirmed that the representative height of the unevenness of the long film 100 is proportional to the area of ​​the unevenness. Therefore, in each measurement unit region 240, the representative height of the unevenness corresponding to the shadow area can be calculated from the area of ​​the shadow area corresponding to the area of ​​the unevenness.

[0087] For example, the height calculation unit 232 may store a table including information on the area of ​​a shadow area that can be measured in one measurement unit area 240 and the representative height of the uneven portion corresponding to the area of ​​the shadow area. The height calculation unit 232 that stores such a table can read out from the table the representative height of the uneven portion corresponding to the area of ​​the shadow area sent from the area measurement unit 231, and obtain the representative height of the uneven portion.

[0088] Also, for example, the height calculation unit 232 may store a function that expresses the relationship between the area of ​​the shadow area that can be measured in one measurement unit area 240 and the representative height of the uneven portion corresponding to the area of ​​the shadow area. This function is usually a linear function. The height calculation unit 232 that stores such a function can calculate the representative height of the uneven portion by applying the area of ​​the shadow area sent from the area measurement unit 231 to the function.

[0089] The above-mentioned table and function can be prepared, for example, by experiments. As a specific example, the area of ​​the shadow area and the representative height of the uneven portion corresponding to the shadow area are repeatedly measured to obtain multiple pieces of information on combinations of the area of ​​the shadow area and the representative height of the uneven portion. The information thus obtained is plotted on a coordinate system with the area of ​​the shadow area and the representative height of the uneven portion as axes, and a calibration curve is drawn. The calibration curve is drawn, for example, as a straight line passing through the origin (i.e., the point where both the area of ​​the shadow area and the representative height of the uneven portion are 0 (zero)) by the least squares method. Then, the table and function can be obtained from this calibration curve.

[0090] The representative height of the uneven portion calculated by the height calculation unit 232 may be a representative value of the height H of the uneven portion 110 included in the measurement unit area 240 that is the measurement target, as shown in FIG. 10. The representative height as the representative value may be, for example, the maximum height, average height, etc. of the uneven portion 110 included in the measurement unit area 240. In particular, as in the example shown in this embodiment, in the uneven portion 110 formed in a planar shape including a corner 130, the height H of the uneven portion 110 tends to be large at the corner 130. Therefore, the height H of the uneven portion 110 at the corner 130 may have a large effect on the handleability of the long film 100. Therefore, in order to improve the handleability of the long film 100, it is preferable to adjust the height H of the uneven portion 110 at the corner 130, and therefore it is preferable to adopt the representative value of the height H of the uneven portion 110 at the corner 130 as the representative height to be measured. In this embodiment, an example will be described in which the average height of the uneven portion 110 at a plurality of corners 130 included in the measurement unit area 240 is adopted as the representative height.

[0091] There is no limitation on the hardware configuration of the above-mentioned height measurement unit 230 and the area measurement unit 231 and height calculation unit 232 included therein. The height measurement unit 230, the area measurement unit 231, and the height calculation unit 232 can be, for example, a computer configured with a processor such as a CPU, memories such as RAM and ROM, interfaces such as input / output terminals, etc. This computer can be configured to perform control according to control contents recorded in advance in a recording device such as a memory.

[0092] The method for measuring the representative height of the concave-convex portion 110 of the long film 100 using the above-mentioned measuring device 200 is as follows: A step (i) of vertically irradiating a long film 100 with parallel light L; A step (ii) of photographing the parallel light L transmitted through the long film 100 to obtain an image; A step (iii) of measuring a representative height of the concave-convex portion 110 of the long film 100 based on the image; Includes.

[0093] 7, the long film 100 is continuously transported in the film longitudinal direction MD and supplied to the measuring device 200. In this embodiment, the long film 100 is unwound from a film roll 150 obtained by winding the long film 100, and supplied to the measuring device 200. At this time, the orientation of the front and back of the long film 100 is not limited. Therefore, the surface of the long film 100 with the concave and convex portions may face either the irradiation unit 210 or the imaging unit 220.

[0094] When the long film 100 is supplied to the measuring device 200, a step (i) is performed in which the irradiation unit 210 irradiates the long film 100 with parallel light L perpendicularly. In detail, light having a wavelength that can be transmitted through the long film 100 is emitted from the light source 211, and the light is converted into parallel light L by transmitting through the collimator lens 212. The parallel light L is then irradiated perpendicularly to the long film 100. Usually, the irradiation unit 210 irradiates the parallel light L onto a portion of the long film 100 that includes at least the concave-convex portion 110. In the example shown in this embodiment, since the concave-convex portion 110 is formed at an end of the long film 100 in the film width direction TD, the irradiation unit 210 irradiates the parallel light L onto the end of the long film 100 in the film width direction TD.

[0095] The parallel light L irradiated from the irradiation unit 210 passes through the long film 100. In the measurement method according to the present embodiment, a step (ii) is performed in which the parallel light L transmitted through the long film 100 is photographed to obtain an image. In detail, the parallel light L transmitted through the long film 100 passes through the object side telecentric lens 222, the aperture 224, and the image side telecentric lens 223 in this order, and is then photographed by the camera 221. The parallel light L photographed by the camera 221 is light that passes straight through a portion of the long film 100 that does not have the uneven portion 110. Therefore, in the image obtained by the camera 221, the photographed parallel light L causes the portions other than the uneven portion 110 to be displayed as relatively bright areas. In addition, the light that passes through the uneven portion 110 is refracted when passing through the uneven portion 110, and therefore cannot pass straight through the long film 100. Therefore, the light transmitted through the uneven portion 110 passes through the object-side telecentric lens 222 and is blocked by the aperture 224, so that it is not captured by the camera 221, or even if it is captured, it is dark. Therefore, in the image acquired by the camera 221, the uneven portion 110 is displayed as a relatively dark shadow area. Information on the image of the long film 100 including the bright and shadow areas in this manner is sent to the height measurement unit 230.

[0096] The height measuring section 230, to which the image information is sent from the photographing section 220, performs a step (iii) of measuring the representative height of the concave-convex portion 110 of the long film 100 based on the image. This step (iii) is A step (iii-1) of measuring the area of ​​a shadow area where the parallel light L cannot pass straight through the long film 100 from the image; A step (iii-2) of calculating a representative height of the uneven portion 110 from the area of ​​the shadow area; Includes.

[0097] In detail, the information of the image acquired by the photographing section 220 is taken into the area measuring section 231. Then, the area measuring section 231 performs a step (iii-1) of measuring the area of ​​the shadow area where the parallel light L could not pass straight through the long film 100 from the taken image. At this time, the area measuring section 231 according to this embodiment measures the area of ​​the shadow area by using the measurement unit area 240 set by dividing it in the film longitudinal direction MD as one unit, as shown in FIG. 10. For example, the number of pixels having a brightness darker than a threshold value among the pixels included in the image may be counted, and the number of pixels may be obtained as the area of ​​the shadow area. The area of ​​the shadow area measured in this way corresponds to the area of ​​the unevenness formed on the long film 100. Therefore, as in the example shown in this embodiment, when the measurement unit area 240 is set so that each measurement unit area 240 includes one knurl portion 120, the area of ​​the measured shadow area corresponds to the area of ​​the entire unevenness 110 forming one knurl portion 120. The information on the area of ​​the shadow area thus measured is sent to the height calculation unit 232 .

[0098] When the height calculation unit 232 receives the information on the area of ​​the shadow area from the area measurement unit 231, it performs a step (iii-2) of calculating the representative height of the uneven portion 110 from the area of ​​the shadow area. That is, since the representative height of the uneven portion of the long film 100 is proportional to the area of ​​the uneven portion represented by the area of ​​the shadow area, the height calculation unit 232 calculates the representative height of the uneven portion 110 included in the measurement unit area 240 from the area of ​​the shadow area. In the example shown in this embodiment, the height calculation unit 232 calculates the average height of the corners 130 of the uneven portion 110 included in the measurement unit area 240 as the representative height from the area of ​​the shadow area in the measurement unit area 240. Usually, the representative height of the uneven portion 110 measured in this way is output to an output device (not shown) connected to the measurement device 200.

[0099] The representative height of the uneven portion 110 can be measured continuously while transporting the long film 100. Therefore, by setting a measurement unit area 240 so as to include each of the knurl portions 120 arranged side by side in the film longitudinal direction MD and performing measurements, the representative height can be measured for each measurement unit area 240, so that the representative height of the uneven portion 110 can be measured for all the knurl portions 120 provided on the long film 100.

[0100] As described above, according to the measurement method of the first embodiment of the present invention, the representative height of the concave-convex portion 110 of the long film 100 can be easily measured. This measurement method can be performed while the long film 100 is continuously transported, and therefore can be applied to the long film 100 transported on a factory line. Moreover, since the representative height can be measured for each measurement unit area 240, by appropriately setting the measurement unit area 240, it is possible to measure the representative heights of the concave-convex portion 110 of various planar shapes.

[0101] [3. Second embodiment of the method for measuring the height of the uneven portion] In the measurement method according to the first embodiment described above, an example is shown in which the long film 100 is divided in the film longitudinal direction MD, and the measurement unit areas 240 are set so that each measurement unit area 240 includes one knurl portion 120, but the measurement unit areas 240 are not limited to those in the first embodiment. For example, the measurement unit areas may be divided and set in both the film longitudinal direction MD and the film width direction TD. An example of this will be described below with reference to the drawings.

[0102] FIG. 11 is a front view showing a measuring device 300 according to a second embodiment of the present invention. As shown in FIG. 11, the measuring device 300 according to the second embodiment of the present invention is a measuring device for measuring the representative height of an uneven portion (not shown in FIG. 11) formed on a long film 100, and includes an irradiation unit 210, an image capturing unit 220, and a height measuring unit 330. This measuring device 300 is provided in the same manner as the measuring device 200 according to the first embodiment, except that the height measuring unit 330 is provided instead of the height measuring unit 230. Therefore, the irradiation unit 210 and the image capturing unit 220 of the measuring device 300 are provided in the same manner as the irradiation unit 210 and the image capturing unit 220 of the measuring device 200 described in the first embodiment. In addition, the height measuring unit 330 is provided in the same manner as the height measuring unit 230 according to the first embodiment, except that the area measuring unit 231 and the height calculating unit 332 are provided instead of the area measuring unit 231 and the height calculating unit 232.

[0103] The area measurement unit 331 is provided in the same manner as the area measurement unit 231 described in the first embodiment, except that the measurement unit area is different. Thus, the area measurement unit 331 is provided so as to take in information about the image acquired by the photographing unit 220, and to measure, from that image, the area of ​​the shadow area where the collimated light L was not able to pass straight through the long film 100. However, this area measurement unit 331 differs from the area measurement unit 231 described in the first embodiment in that the measurement unit areas are set not only in the film longitudinal direction MD, but also in the film width direction TD.

[0104] Fig. 12 is an enlarged plan view showing the vicinity of an end in the film width direction TD of the long film 100 to be measured in the measurement method according to the second embodiment of the present invention. In Fig. 12, the measurement unit areas 341, 342, 343, and 344 are shown separated from each other, but the measurement unit areas 341, 342, 343, and 344 may be set without any space between them. As shown in Fig. 12, the measurement unit areas 341, 342, 343, and 344 as units for measuring the area of ​​the shadow area by the area measurement unit 331 according to the second embodiment are set in both the film longitudinal direction MD and the film width direction TD of the long film 100. Therefore, the area measurement unit 331 is provided so that the area of ​​the shadow area can be measured by using the measurement unit areas 341, 342, 343, and 344 set in both the film longitudinal direction MD and the film width direction TD as one unit.

[0105] In the example shown in this embodiment, the measurement unit areas 341, 342, 343, and 344 correspond to the areas obtained by dividing the measurement unit area 240 adopted in the first embodiment in the film width direction TD. Therefore, the measurement unit areas 341, 342, 343, and 344 are arranged in the film width direction TD, and a single knurl portion 120 can be included in the measurement unit areas 341, 342, 343, and 344 as a whole by combining them. These measurement unit areas 341, 342, 343, and 344 may be referred to as the first measurement unit area 341, the second measurement unit area 342, the third measurement unit area 343, and the fourth measurement unit area 344 in the order from the side farthest from the end of the long film 100 in the film width direction. Therefore, the first measurement unit area 341 is set to include the part farthest from the end of the long film 100 in the film width direction TD when the knurl portion 120 is divided into four in the film width direction TD. The second measurement unit area 342 is set to include the second farthest part from the end of the long film 100 in the film width direction when the knurl portion 120 is divided into four parts in the film width direction TD. The third measurement unit area 343 is set to include the third farthest part from the end of the long film 100 in the film width direction when the knurl portion 120 is divided into four parts in the film width direction TD. The fourth measurement unit area 344 is set to include the fourth farthest part from the end of the long film 100 in the film width direction when the knurl portion 120 is divided into four parts in the film width direction TD. The area measurement unit 331 is provided so as to measure the area of ​​the shadow area for each of the measurement unit areas 341 to 344 set in this way and send the information on the measured area to the height calculation unit 332.

[0106] The height calculation unit 332 is provided in the same manner as the height calculation unit 232 described in the first embodiment, except that the measurement of the representative height of the uneven portion 110 is performed not for the measurement unit area 240 but for each of the measurement unit areas 341 to 344 corresponding to the areas obtained by dividing the measurement unit area 240. Therefore, the height calculation unit 332 is provided so as to take in information on the area of ​​the shadow area measured by the area measurement unit 331 for each of the measurement unit areas 341 to 344, and to calculate the representative height of the uneven portion included in each of the measurement unit areas 341 to 344 from the area. The calculation may be performed using a table or a function, as in the first embodiment. For example, the height calculation unit 332 may store a table including the area of ​​the shadow area and the information on the representative height of the uneven portion corresponding to the area of ​​the shadow area for each of the measurement unit areas 341 to 344, and the representative height of the uneven portion corresponding to the area of ​​the shadow area may be read from the table to obtain the representative height of the uneven portion. Also, for example, the height calculation unit 332 may store a function that expresses the relationship between the area of ​​the shadow area and the representative height of the uneven portion corresponding to the area of ​​the shadow area for each of the measurement unit regions 341 to 344, and may calculate the area of ​​the shadow area sent from the area measurement unit 331 by applying the function to obtain the representative height of the uneven portion.

[0107] The method for measuring the representative height of the concave-convex portion 110 of the long film 100 using the above-mentioned measuring device 300 includes a step (i) of vertically irradiating the long film 100 with parallel light L, and a step (ii) of capturing the parallel light L transmitted through the long film 100 to obtain an image. In the measuring method according to the second embodiment, the steps (i) and (ii) can be performed in the same manner as in the first embodiment. By performing the steps (i) and (ii), an image of the long film 100 including the shadow area corresponding to the concave-convex portion 110 and the bright area corresponding to the portion other than the concave-convex portion 110 can be obtained, as in the first embodiment. The information on the image is sent to the height measuring unit 330.

[0108] The height measuring unit 330, to which the image information is sent from the photographing unit 220, performs step (iii) of measuring the representative height of the uneven portion 110 of the long film 100 based on the image. As in the first embodiment, this step (iii) includes step (iii-1) of measuring the area of ​​the shadow area where the parallel light L was not able to pass straight through the long film 100 from the image, and step (iii-2) of calculating the representative height of the uneven portion 110 from the area of ​​the shadow area.

[0109] In detail, the image information acquired by the photographing section 220 is input to the area measuring section 331. Then, the area measuring section 331 performs a step (iii-1) of measuring the area of ​​the shadow area where the parallel light L could not pass straight through the long film 100 from the input image. This step (iii-1) can be performed in the same manner as the step (iii-1) described in the first embodiment, except that the measurement of the area of ​​the shadow area is performed not for the measurement unit area 240 but for each of the measurement unit areas 341 to 344 corresponding to the area obtained by dividing the measurement unit area 240. Therefore, the area measuring section 331 according to this embodiment measures the area of ​​the shadow area by using each of the measurement unit areas 341 to 344 set by dividing both the film longitudinal direction MD and the film width direction TD as one unit, as shown in FIG. 12. Unlike the first embodiment, the area of ​​the shadow area measured in each of the measurement unit areas 341 to 344 corresponds to the area of ​​each of the portions obtained by dividing one knurl portion 120 in the film width direction TD. The information on the area of ​​the shadow area thus measured is sent to the height calculation unit 332 .

[0110] When the height calculation unit 332 receives the information on the area of ​​the shadow area from the area measurement unit 331, it performs a step (iii-2) of calculating the representative height of the uneven portion 110 from the area of ​​the shadow area. This step (iii-2) can be performed in the same manner as the step (iii-2) described in the first embodiment, except that the measurement of the representative height of the uneven portion 110 is performed not for the measurement unit area 240 but for each of the measurement unit areas 341 to 344 corresponding to the area obtained by dividing the measurement unit area 240. Therefore, the height calculation unit 332 calculates the representative height of the uneven portion 110 included in each of the measurement unit areas 341 to 344 from the area of ​​the shadow area in each of the measurement unit areas 341 to 344. The representative height of the uneven portion 110 measured in this manner can be output by an output device (not shown) connected to the measurement device 300, as in the first embodiment.

[0111] The representative height of the uneven portion 110 can be measured continuously while the long film 100 is being transported. In this embodiment, one knurl portion 120 is divided in the film width direction TD by a plurality of measurement unit areas 341-344 set at the same position in the film longitudinal direction MD, and the area of ​​the shadow area is measured. Therefore, the representative height of the uneven portion 110 included in one knurl portion 120 can be measured in each of the measurement unit areas 341-344. Therefore, the distribution of the height of the uneven portion 110 in the film width direction TD can be measured, so detailed information on the height H of the uneven portion 110 can be obtained. In addition, according to the measurement method of the second embodiment, the same advantages as those of the first embodiment can be obtained.

[0112] [4. Third embodiment of the method for producing a long film] As described above, the area of ​​the unevenness formed on the long film as viewed from the thickness direction is proportional to the representative height of the unevenness. Therefore, when the area of ​​the unevenness is measured and the unevenness is formed while feedback-controlling the forming conditions of the unevenness based on the measured area, a long film having unevenness of a desired height can be easily manufactured. The manufacture of such a long film having unevenness can be carried out, for example, by the manufacturing method described below.

[0113] 13 is a front view showing a schematic diagram of a manufacturing apparatus 400 according to a third embodiment of the present invention. As shown in FIG. 13, the manufacturing apparatus 400 according to the third embodiment of the present invention is an apparatus for manufacturing a long film 100, and includes a concave-convex forming section 410 and a height control section 420.

[0114] The unevenness forming section 410 is provided so that an uneven portion (not shown in FIG. 13) can be formed in a resin film 500, which is a film containing resin, to obtain a long film 100. In the following description, the resin film 500 before the uneven portion is formed may be referred to as an "unprocessed film" 500. The unevenness forming section 410 is preferably one that can form an uneven portion by processing using laser light or heat.

[0115] The unevenness forming unit 410, which can form unevenness by processing using laser light, is usually equipped with a laser processing device. The laser processing device can form unevenness in the unprocessed film 500 by irradiating the unprocessed film 500 with laser light. In detail, when the laser processing device irradiates at least one surface of the unprocessed film 500 with laser light, localized thermal melting or ablation occurs at the location irradiated with the laser light. Therefore, unevenness can be formed in the unprocessed film 500 at the location irradiated with the laser light.

[0116] During the above-mentioned irradiation of the laser light, the irradiation point P (see Figs. 5 and 6) where the laser light hits the unprocessed film 500 may be moved so as to draw the planar shape of the unevenness to be formed. As a result, the unevenness is formed at the trace of the movement of the irradiation point P of the laser light, so that the unevenness having the desired planar shape can be formed. The movement speed of the irradiation point P of the laser light can be set arbitrarily within a range in which the desired unevenness can be formed. The specific movement speed is preferably 500 mm / s or more, more preferably 1000 mm / s or more, particularly preferably 1500 mm / s or more, and preferably 10000 mm / s or less, more preferably 9000 mm / s or less, particularly preferably 8000 mm / s or less.

[0117] The laser processing device is usually equipped with a laser device that is a laser light irradiation device. Examples of this laser device include an ArF excimer laser device, a KrF excimer laser device, a XeCl excimer laser device, a YAG laser device (particularly, the third harmonic or the fourth harmonic), a YLF or YVO4 solid-state laser device (particularly, the third harmonic or the fourth harmonic), a Ti:S laser device, a semiconductor laser device, a fiber laser device, and a carbon dioxide gas laser device. Among these laser devices, a carbon dioxide gas laser device is preferable from the viewpoint of being relatively inexpensive and being able to efficiently obtain an output suitable for processing a film.

[0118] The output of the laser light is preferably 1 W or more, more preferably 5 W or more, and even more preferably 15 W or more, and is preferably 120 W or less, more preferably 100 W or less, even more preferably 80 W or less, and even more preferably 70 W or less. When the output of the laser light is equal to or more than the lower limit, the insufficient amount of the laser light can be suppressed, and the unevenness can be stably formed. When the output of the laser light is equal to or less than the upper limit, the generation of through holes in the film 500 can be suppressed.

[0119] The unevenness forming section 410 capable of forming unevenness by processing using heat is usually equipped with a thermal processing device. The thermal processing device is provided so as to be able to heat the unprocessed film 500. In general, the resin contained in the unprocessed film 500 can become flexible by heating, so that the unprocessed film 500 is heated and pressed with a mold having an unevenness pattern corresponding to the shape of the unevenness, whereby the unevenness pattern of the mold is transferred to the unprocessed film 500, and unevenness can be formed on the unprocessed film 500. As the mold, for example, a roll-shaped or ring-shaped mold (e.g., knurling, etc.) having an unevenness pattern on its side can be used. In this case, a thermal processing device may be prepared separately from the mold, or the mold itself may be heated and used as the heat processing device.

[0120] In this embodiment, an example will be described in which an unevenness forming section 410 equipped with a laser processing device is used as the processing device 411 so that unevenness can be formed on the unprocessed film 500 by processing using laser light B.

[0121] The unevenness forming section 410 is usually provided so as to be able to form a plurality of unevenness portions aligned in the film width direction MD. In this embodiment, an example will be described in which the unevenness forming section 410 is provided so as to be able to form a plurality of unevenness portions aligned in the film longitudinal direction MD at the end of the unprocessed film 500 in the film width direction TD so as to obtain the long film 100 shown in FIG.

[0122] The height control unit 420 includes an irradiation unit 210, an imaging unit 220, and a feedback control unit 430 so as to control the height of the unevenness formed by the unevenness forming unit 410. The irradiation unit 210 is provided in the same manner as in the first embodiment so as to irradiate the long film 100 with parallel light L. The imaging unit 220 is provided in the same manner as in the first embodiment so as to capture the parallel light L transmitted through the long film 100 and obtain an image. Therefore, the height control unit 420 according to this embodiment is provided so that the imaging unit 220 can capture the parallel light L irradiated from the irradiation unit 210 and transmitted through the long film 100, and send information on the image obtained by the capture to the feedback control unit 430.

[0123] The feedback control unit 430 includes an area measurement unit 231 and a condition control unit 433. The feedback control unit 430 may further include a height calculation unit 232.

[0124] The area measurement unit 231 is provided in the same manner as in the first embodiment so as to take in information about the image acquired by the photographing unit 220 and measure, from the image, the area of ​​the shadow area where the collimated light L was not able to pass straight through the long film 100. The area measurement unit 231 is also provided so as to be able to send information about the area of ​​the shadow area measured by the area measurement unit 231 to the condition control unit 433 and the height calculation unit 232.

[0125] The condition control unit 433 is provided so as to take in the information on the area of ​​the shadow area measured by the area measurement unit 231, and to control the conditions for forming the unevenness in the unevenness forming unit 410 based on the area of ​​the shadow area. As described above, the area of ​​the unevenness as viewed from the thickness direction, which corresponds to the area of ​​the shadow area, is proportional to the representative height of the unevenness. Therefore, by controlling the conditions for forming the unevenness in the unevenness forming unit 410 so that the area of ​​the shadow area falls within a predetermined range, it is possible to control the representative height of the unevenness to a desired height. Therefore, the condition control unit 433 is provided so as to control the conditions for forming the unevenness in the unevenness forming unit 410 so that the area of ​​the shadow area falls within a predetermined range corresponding to the desired representative height required for the unevenness of the long film 100.

[0126] For example, consider a case where it is desired to obtain a long film 100 having a uniform representative height of the concave-convex portions throughout the entire length of the film by keeping the representative height of the concave-convex portions constant during the manufacturing period of the long film 100. In this case, the condition control unit 433 may be provided so as to control the conditions for forming the concave-convex portions in the concave-convex forming unit 410 so that the area of ​​the shadow area measured by the area measuring unit 231 falls within a predetermined target range that is set constant throughout the manufacturing period of the long film 100. Thus, when the area of ​​the shadow area measured by the area measuring unit 231 is smaller than the lower limit of the target range, the condition control unit 433 may control the conditions for forming the concave-convex portions in the concave-convex forming unit 410 so that the area of ​​the shadow area becomes larger. Also, when the area of ​​the shadow area measured by the area measuring unit 231 is larger than the upper limit of the target range, the condition control unit 433 may control the conditions for forming the concave-convex portions in the concave-convex forming unit 410 so that the area of ​​the shadow area becomes smaller. When the long film 100 is manufactured by repeatedly performing this control based on the area of ​​the shadow area, the area of ​​the shadow area can be kept within a specified target range and the representative height of the uneven portion can be maintained constant, so that the long film 100 having uneven portions with a uniform representative height throughout the entire longitudinal direction of the film can be manufactured.

[0127] Also, for example, consider a case where it is desired to obtain a long film 100 having a distribution of the representative height in the longitudinal direction of the film by increasing the representative height of the concave-convex portion continuously or stepwise over time during the production of the long film 100. In this case, the condition control unit 433 may be provided so as to control the conditions for forming the concave-convex portion in the concave-convex portion forming unit 410 so that the area of ​​the shadow area measured by the area measuring unit 231 falls within a predetermined target range set so as to increase continuously or stepwise over time. When the long film 100 is produced while repeatedly performing this control based on the area of ​​the shadow area, the area of ​​the shadow area can be increased as the target range increases, and therefore the representative height of the concave-convex portion can be increased, so that a long film 100 having a distribution in which the representative height of the concave-convex portion increases continuously or stepwise in the longitudinal direction of the film can be produced.

[0128] Furthermore, for example, consider a case where it is desired to obtain a long film 100 having a distribution of the representative height in the longitudinal direction of the film by continuously or stepwise lowering the representative height of the concave-convex portion over time during the production of the long film 100. In this case, the condition control unit 433 may be provided so as to control the conditions for forming the concave-convex portion in the concave-convex forming unit 410 so that the area of ​​the shadow area measured by the area measuring unit 231 falls within a predetermined target range set so as to continuously or stepwise decrease over time. When the long film 100 is produced while repeatedly performing this control based on the area of ​​the shadow area, the area of ​​the shadow area can be reduced as the target range becomes smaller, and therefore the representative height of the concave-convex portion can be reduced, so that a long film 100 having a distribution in which the representative height of the concave-convex portion decreases continuously or stepwise in the longitudinal direction of the film can be produced.

[0129] When increasing or decreasing the area of ​​the shadow area measured by area measuring unit 231, how to control the conditions for forming the unevenness in unevenness forming unit 410 can be appropriately selected depending on the processing employed by unevenness forming unit 410. For example, as in the example shown in this embodiment, when unevenness forming unit 410 forms the unevenness by processing using laser light, the area of ​​the shadow area may be adjusted by the following control.

[0130] Usually, the higher the output of the laser light, the higher the height of the uneven portion, and the area of ​​the uneven portion tends to increase accordingly. Therefore, the condition control unit 433 may control to increase the output of the laser light irradiated from the unevenness forming unit 410 to the unprocessed film 500, thereby increasing the area of ​​the shadow area corresponding to the area of ​​the uneven portion. In addition, the condition control unit 433 may control to decrease the output of the laser light irradiated from the unevenness forming unit 410 to the unprocessed film 500, thereby decreasing the area of ​​the shadow area corresponding to the area of ​​the uneven portion.

[0131] Furthermore, in an uneven portion having a planar shape including corners, the smaller the radius of curvature of the corners (see radius of curvature R in FIG. 4), the higher the uneven portion becomes, and the area of ​​the uneven portion tends to increase accordingly. Therefore, condition control unit 433 may perform control to reduce the radius of curvature of the corners of the uneven portion, thereby increasing the area of ​​the shadow area corresponding to the area of ​​the uneven portion. Condition control unit 433 may also perform control to increase the radius of curvature of the corners of the uneven portion, thereby decreasing the area of ​​the shadow area corresponding to the area of ​​the uneven portion.

[0132] For example, when the unevenness forming section 410 forms the unevenness by processing using heat, the area of ​​the shadow area may be adjusted by the following control.

[0133] Usually, in processing using heat, the greater the heat given to the unprocessed film 500, the greater the height of the unevenness, and the greater the area of ​​the unevenness. Therefore, the condition control unit 433 may control the amount of heat given to the unprocessed film 500 from the unevenness forming unit 410 to increase the area of ​​the shadow area corresponding to the area of ​​the unevenness. The condition control unit 433 may also control the amount of heat given to the unprocessed film 500 from the unevenness forming unit 410 to decrease the area of ​​the shadow area corresponding to the area of ​​the unevenness.

[0134] Furthermore, in processing that includes pressing with a mold, the greater the pressure with which the mold presses the unprocessed film 500, the greater the height of the uneven portion, and the greater the area of ​​the uneven portion. Therefore, the condition control unit 433 may perform control to increase the pressure with which the mold presses the unprocessed film 500, thereby increasing the area of ​​the shadow area corresponding to the area of ​​the uneven portion. Furthermore, the condition control unit 433 may perform control to decrease the pressure with which the mold presses the unprocessed film 500, thereby decreasing the area of ​​the shadow area corresponding to the area of ​​the uneven portion.

[0135] In this embodiment, an example will be described in which the condition control unit 433 is configured to adjust the area of ​​the shadow area, which corresponds to the area of ​​the uneven portion, by controlling the output of the laser light B irradiated by the processing device 411.

[0136] The height calculation unit 232 is provided in the same manner as in the first embodiment so as to take in information on the area of ​​the shadow area measured by the area measurement unit 231 and calculate, from that area, the representative height of the uneven portion of the long film 100. Usually, the height calculation unit 232 is provided so as to be able to output the measured representative height of the uneven portion 110 to an output device (not shown) connected to the manufacturing apparatus 400.

[0137] The manufacturing method of the long film 100 using the above-mentioned manufacturing apparatus 400 is as follows: A step (I) of forming a concave-convex portion on the unprocessed film 500 to obtain a long film 100; A step (II) of controlling the height of the uneven portion formed in the step (I); Includes.

[0138] 13, a long unprocessed film 500 is continuously transported in the film longitudinal direction MD, and the unprocessed film 500 is supplied to the manufacturing apparatus 400. In this embodiment, the unprocessed film 500 is unwound from a film roll 510 obtained by winding up the unprocessed film 500, and supplied to the manufacturing apparatus 400.

[0139] When the unprocessed film 500 is supplied to the manufacturing apparatus 400, the unevenness forming section 410 performs a step (I) of forming uneven portions on the unprocessed film 500. In this embodiment, as shown in FIG. 13, a processing device 411 provided in the unevenness forming section 410 irradiates the unprocessed film 500 with laser light B. This laser light B forms uneven portions on the unprocessed film 500, and a long film 100 is obtained. In this embodiment, an example will be described in which a plurality of uneven portions 110 are formed side by side in the film longitudinal direction MD at the end of the film width direction TD as shown in FIG. The long film 100 obtained in this manner is sent to the height control section 420.

[0140] When the long film 100 is sent to the height control section 420, the height control section 420 performs step (II) of controlling the height of the uneven portion formed in step (I). This step (II) includes a step (II-1) of vertically irradiating the long film 100 with parallel light L, a step (II-2) of photographing the parallel light L transmitted through the long film 100 to obtain an image, a step (II-3) of measuring the area of ​​the shadow area from the image, and a step (II-4) of controlling the conditions for forming the uneven portion in step (I) based on the area of ​​the shadow area.

[0141] That is, in step (II), similar to step (i) of the measurement method described in the first embodiment, a step (II-1) is performed in which the irradiating unit 210 irradiates the long film 100 with parallel light L perpendicularly. In the example shown in this embodiment, as shown in Fig. 1, since the concave-convex portion 110 is formed at the end of the long film 100 in the film width direction TD, the irradiating unit 210 irradiates the end of the long film 100 in the film width direction TD with parallel light L.

[0142] The parallel light L irradiated from the irradiation unit 210 passes through the long film 100. As in step (ii) of the measurement method described in the first embodiment, the imaging unit 220 captures the parallel light L that has passed through the long film 100 to obtain an image (II-2). In the obtained image, the uneven portion 110 is displayed as a relatively dark shadow area. Information on the image of the long film 100 is sent to the feedback control unit 430.

[0143] In the feedback control unit 430 to which the image information is sent from the photographing unit 220, the area measurement unit 231 captures the image information. Then, the area measurement unit 231 performs a step (II-3) of measuring the area of ​​the shadow area where the parallel light L could not pass straight through the long film 100 from the captured image, similar to the step (iii-1) of the measurement method described in the first embodiment. Therefore, as shown in FIG. 10, the area measurement unit 231 measures the area of ​​the shadow area, with the measurement unit area 240 set at least in the film longitudinal direction MD as one unit. As in the first embodiment, in the example shown in this embodiment, the measurement unit area 240 is set so that each measurement unit area 240 includes one knurl portion 120, so that the area of ​​the measured shadow area corresponds to the area of ​​the entire uneven portion 110 forming one knurl portion 120. The information on the area of ​​the shadow area measured in this manner is sent to the condition control unit 433 and the height calculation unit 232.

[0144] When the condition control unit 433 receives the information on the area of ​​the shadow area from the area measurement unit 231, it performs a step (II-4) of controlling the conditions for forming the unevenness in step (I) based on the area of ​​the shadow area. This step (II-4) usually includes controlling the conditions for forming the unevenness in step (I) so that the area of ​​the shadow area falls within a predetermined range corresponding to the desired representative height required for the unevenness of the long film 100. For example, when the conditions for forming the unevenness are controlled so that the area of ​​the shadow area falls within a predetermined range that is set constant throughout the manufacturing period of the long film 100, the representative height of the unevenness can be made uniform.

[0145] The above control is usually performed for each measurement unit area 240 set as shown in FIG. 10. Therefore, in the step (II-4), the conditions for forming the uneven portion in the step (I) can be controlled so that the area of ​​the shadow area measured in the measurement unit area 240 as one unit falls within a predetermined range. In the example shown in this embodiment, the measurement unit area 240 is set so that each measurement unit area 240 includes one knurl portion 120, as in the first embodiment. Therefore, the condition control unit 433 controls the conditions for forming the uneven portion in the step (I) so that the area of ​​the shadow area corresponding to the area of ​​the uneven portion 110 included in one knurl portion 120 falls within a predetermined range. By performing such control, the representative height of the knurl portion 120 included in each measurement unit area 240 can be controlled to a desired height.

[0146] A specific example of the control method by the condition control unit 433 will be described below. In this specific example, in order to keep the representative height of the unevenness constant during the manufacturing period of the long film 100, a predetermined range in which the area of ​​the shadow area should fall is set constant throughout the entire manufacturing period of the long film 100. In this specific example, the condition control unit 433 controls the area of ​​the shadow area by controlling the output of the laser light B irradiated from the unevenness forming unit 410. In the control method according to this specific example, the condition control unit 433 acquires information on the area of ​​the shadow area measured by the area measuring unit 231 (step 1). The condition control unit 433 judges whether the acquired area of ​​the shadow area is smaller than the lower limit of the predetermined range (step 2). If it is judged that the area of ​​the shadow area is smaller than the lower limit, the condition control unit 433 increases the output of the laser light B irradiated from the unevenness forming unit 410, performs control to increase the area of ​​the shadow area (step 3), and ends the control. On the other hand, if it is determined that the area of ​​the shadow area is not smaller than the lower limit, the condition control unit 433 determines whether the area of ​​the captured shadow area is larger than the upper limit of the predetermined range (step 4). If it is determined that the area of ​​the shadow area is larger than the upper limit, the condition control unit 433 reduces the output of the laser light B irradiated from the unevenness forming unit 410 to reduce the area of ​​the shadow area (step 5), and ends the control. On the other hand, if it is determined that the area of ​​the shadow area is not larger than the upper limit, the condition control unit 433 does not change the output of the laser light B irradiated from the unevenness forming unit 410, and ends the control. By repeatedly performing the control method shown in this specific example while forming the unevenness on the long film 100, the representative height of the unevenness can be made constant during the manufacturing period of the long film 100, and the representative height of the unevenness 110 can be made uniform.

[0147] When the feedback control unit 430 has the height calculation unit 232, the height calculation unit 232 may take in the area information of the shadow area sent from the area measurement unit 231, and perform step (III) of calculating the representative height of the unevenness portion 110 from the area of ​​the taken-in shadow area, similar to step (iii-2) of the measurement method described in the first embodiment. Usually, the representative height of the unevenness portion 110 measured in this manner is output to an output device (not shown) connected to the manufacturing apparatus 400.

[0148] According to the above-described manufacturing method, the representative height of the concave-convex portion of the long film 100 can be controlled to a desired height while continuously manufacturing the long film 100. Usually, the long film 100 manufactured in this manner is wound up and collected as a roll 160. Furthermore, when the representative height of the concave-convex portion is calculated by the height calculation unit 232, the representative height of the concave-convex portion 110 can be measured simultaneously with the manufacturing of the long film 100, so that the same advantages as those described in the first embodiment can be obtained.

[0149] [5. Fourth embodiment of the method for producing a long film] In the manufacturing method according to the third embodiment described above, an example has been shown in which the long film 100 is divided in the film longitudinal direction MD, and the measurement unit areas 240 are set so that each measurement unit area 240 includes one knurl portion 120. However, in the manufacturing method for the long film 100, the measurement unit areas may be set in a manner different from that of the third embodiment. For example, the measurement unit areas may be divided and set in both the film longitudinal direction MD and the film width direction TD, as explained in the measurement method according to the second embodiment. An example of this will be explained below with reference to the drawings.

[0150] Fig. 14 is a front view showing a manufacturing apparatus 600 according to a fourth embodiment of the present invention. As shown in Fig. 14, the manufacturing apparatus 600 according to the fourth embodiment of the present invention is a manufacturing apparatus for a long film 100, and includes a concave-convex forming section 410 and a height control section 620. This manufacturing apparatus 600 is provided in the same manner as the manufacturing apparatus 400 according to the third embodiment, except that the manufacturing apparatus 600 includes the height control section 620 instead of the height control section 420. Therefore, the concave-convex forming section 410 of the manufacturing apparatus 600 is provided in the same manner as the concave-convex forming section 410 of the manufacturing apparatus 400 described in the third embodiment.

[0151] The height control unit 620 includes an irradiation unit 210, an imaging unit 220, and a feedback control unit 630. This height control unit 620 is provided in the same manner as the manufacturing apparatus 400 according to the third embodiment, except that the height control unit 620 includes the feedback control unit 630 instead of the feedback control unit 430. Therefore, the irradiation unit 210 of the height control unit 620 is provided in the same manner as the irradiation unit 210 described in the third embodiment. Moreover, the imaging unit 220 of the height control unit 620 is provided in the same manner as the imaging unit 220 described in the third embodiment.

[0152] The feedback control unit 630 includes an area measurement unit 331 and a condition control unit 633. The feedback control unit 630 may further include a height calculation unit 332.

[0153] The area measurement unit 331 is provided in the same manner as the area measurement unit 331 described in the second embodiment. Therefore, the area measurement unit 331 is provided so as to take in the information of the image acquired by the photographing unit 220, and measure the area of ​​the shadow area from the image, with the measurement unit areas 341, 342, 343, and 344 set in both the film longitudinal direction MD and the film width direction TD as one unit, as shown in FIG. 12. In the example shown in this embodiment, like the example according to the second embodiment, the measurement unit areas 341, 342, 343, and 344 are arranged in the film width direction TD, and a knurl portion 120 as a whole, which is a combination of them, can be included in the measurement unit areas 341, 342, 343, and 344. In addition, the area measurement unit 331 is provided so as to measure the area of ​​the shadow area for each of the measurement unit areas 341 to 344, and to send the information of the measured area to the condition control unit 633 and the height calculation unit 332.

[0154] The condition control section 633 is provided in the same manner as the condition control section 433 described in the third embodiment, except that the condition control section 633 controls the conditions for forming the unevenness in the unevenness forming section 410 not for the measurement unit area 240 but for each of the measurement unit areas 341 to 344 corresponding to the areas obtained by dividing the measurement unit area 240. Thus, the condition control section 633 is provided so as to take in information on the area of ​​the shadow area measured by the area measurement section 331 for each of the measurement unit areas 341 to 344, and to control the conditions for forming the unevenness in the unevenness forming section 410 for each of the measurement unit areas 341 to 344 based on the area. Specifically, the condition control section 633 is provided so as to control the conditions for forming the unevenness in the unevenness forming section 410 for each of the measurement unit areas 341 to 344 so that the area of ​​the shadow area falls within a predetermined range corresponding to the desired representative height required for the unevenness of the long film 100. In this embodiment, an example is given in which the condition control unit 633 is configured to control the output of the laser light B irradiated by the processing device 411 so as to adjust the area of ​​the shadow area, which corresponds to the area of ​​the uneven portion, for each of the measurement unit regions 341 to 344.

[0155] The height calculation unit 332 is provided in the same manner as in the third embodiment so as to take in information on the area of ​​the shadow area measured by the area measurement unit 331 and calculate, from that area, the representative height of the uneven portion of the long film 100 in each of the measurement unit regions 341 to 344. Usually, the height calculation unit 332 is provided so as to be able to output the measured representative height of the uneven portion 110 to an output device (not shown) connected to the manufacturing apparatus 600.

[0156] The manufacturing method of the long film 100 using the manufacturing apparatus 600 described above includes a step (I) of forming an uneven portion in the unprocessed film 500 to obtain the long film 100, and a step (II) of controlling the height of the uneven portion formed in the step (I). In the manufacturing method according to the fourth embodiment, the step (I) can be performed in the same manner as in the third embodiment. When the step (I) is performed, an uneven portion is formed in the unprocessed film 500, as in the third embodiment, and the long film 100 is obtained. The long film 100 thus obtained is sent to a height control unit 620.

[0157] When the long film 100 is sent to the height control unit 620, the height control unit 620 performs step (II) of controlling the height of the uneven portion formed in step (I). This step (II) includes step (II-1) of vertically irradiating the long film 100 with parallel light L; step (II-2) of photographing the parallel light L transmitted through the long film 100 to obtain an image; step (II-3) of measuring the area of ​​the shadow area from the image; and step (II-4) of controlling the conditions for forming the uneven portion in step (I) based on the area of ​​the shadow area. In the manufacturing method according to the fourth embodiment, steps (II-1) and (II-2) can be performed in the same manner as in the third embodiment. When steps (II-1) and (II-2) are performed, an image of the long film 100 including the shadow area corresponding to the uneven portion 110 is obtained as in the third embodiment, and the information of the image is sent to the feedback control unit 630.

[0158] In the feedback control unit 630 to which the image information is sent from the photographing unit 220, the area measurement unit 331 captures the image information. Then, the area measurement unit 331 performs a step (II-3) of measuring the area of ​​the shadow area where the parallel light L could not pass straight through the long film 100 from the captured image, similar to the step (iii-1) of the measurement method described in the second embodiment. At this time, the area measurement unit 331 according to this embodiment measures the area of ​​the shadow area by using the measurement unit areas 341 to 344 set in both the film longitudinal direction MD and the film width direction TD as one unit, as shown in FIG. 12. Therefore, unlike the third embodiment, the area of ​​the shadow area measured in each of the measurement unit areas 341 to 344 corresponds to the area of ​​each part obtained by dividing one knurl part 120 in the film width direction TD. The information on the area of ​​the shadow area measured in this way is sent to the condition control unit 633 and the height calculation unit 332.

[0159] When the condition control unit 633 receives the information on the area of ​​the shadow area from the area measurement unit 331, the condition control unit 633 performs a step (II-4) of controlling the conditions for forming the unevenness in the step (I) based on the area of ​​the shadow area. This step (II-4) can be performed in the same manner as the step (II-4) described in the third embodiment, except that the control of the conditions for forming the unevenness in the unevenness forming unit 410 is performed not for the measurement unit area 240 but for each of the measurement unit areas 341 to 344 corresponding to the areas obtained by dividing the measurement unit area 240. Therefore, the condition control unit 633 can control the conditions for forming the unevenness on the unprocessed film 500 in the step (I) so that the areas of the shadow areas measured with each of the measurement unit areas 341 to 344 as one unit are each within a predetermined range. Specifically, the condition control unit 633 can control the conditions for forming the uneven portion in the region located at the same position in the film width direction TD as the first measurement unit region 341 so that the area of ​​the shadow area measured in the first measurement unit region 341 falls within a predetermined range. The condition control unit 633 can also control the conditions for forming the uneven portion in the region located at the same position in the film width direction TD as the second measurement unit region 342 so that the area of ​​the shadow area measured in the second measurement unit region 342 falls within a predetermined range. The condition control unit 633 can also control the conditions for forming the uneven portion in the region located at the same position in the film width direction TD as the third measurement unit region 343 so that the area of ​​the shadow area measured in the third measurement unit region 343 falls within a predetermined range. Furthermore, the condition control unit 633 can control the conditions for forming the uneven portion in the region located at the same position in the film width direction TD as the fourth measurement unit region 344 so that the area of ​​the shadow area measured in the fourth measurement unit region 344 falls within a predetermined range. By carrying out such control, the representative height of the concave and convex portions in each of the measurement unit areas 341 to 344 can be controlled to a desired height.

[0160] When the feedback control unit 630 has a height calculation unit 332, the height calculation unit 332 may perform a step (III) of taking in the area information of the shadow area sent from the area measurement unit 331 and calculating the representative height of the unevenness portion 110 from the area of ​​the taken in shadow area, similar to the step (iii-2) of the measurement method described in the second embodiment. Usually, the representative height of the unevenness portion 110 measured in this manner is output to an output device (not shown) connected to the manufacturing apparatus 600.

[0161] According to the above-mentioned manufacturing method, while continuously manufacturing the long film 100, the representative height of the concave-convex portion of the long film 100 can be controlled to a desired height. In addition, in this embodiment, one knurl portion 120 is divided in the film width direction TD by a plurality of measurement unit areas 341-344 set at the same position in the film longitudinal direction MD, and the representative height of the concave-convex portion is controlled in each of these measurement unit areas 341-344. Therefore, since the distribution of the height of the concave-convex portion 110 in the film width direction TD can be controlled, the height H of the concave-convex portion 110 can be precisely controlled. Furthermore, according to the manufacturing method of this embodiment, the same advantages as those described in the third embodiment can be obtained.

[0162] [6. Fifth embodiment of the method for producing a long film] In the above-described third and fourth embodiments, examples have been shown in which the unevenness forming unit 410 forms all the unevenness portions by a single processing device 411, but the unevenness portions may be formed by a plurality of processing devices. For example, when the conveying speed of the unprocessed film 500 is high, the stability of the formation of the unevenness portions may decrease with a single processing device 411 depending on the processing capacity of the processing device 411. Therefore, the unevenness portions may be formed by a plurality of processing devices 411. An example of this will be described below with reference to the drawings.

[0163] 15 is a front view showing a schematic diagram of a manufacturing apparatus 700 according to a fifth embodiment of the present invention. As shown in FIG. 15, the manufacturing apparatus 700 according to the fifth embodiment of the present invention is an apparatus for manufacturing a long film 100, and includes a concave-convex forming unit 710 and a height control unit 720.

[0164] The unevenness forming unit 710 is provided in the same manner as the unevenness forming unit 410 according to the third embodiment, except that it is provided with a plurality of processing devices 711 and 712. The processing devices 711 and 712 may be the same as those described in the third embodiment. In this embodiment, an example will be described in which laser processing devices capable of forming uneven portions by irradiating laser light B are used as the processing devices 711 and 712.

[0165] 16 is an enlarged plan view showing the vicinity of an end portion in the film width direction TD of the long film 100 produced by using the production apparatus 700 according to the fifth embodiment of the present invention. The processing devices 711 and 712 are provided so as to be able to form the uneven portion 110 at the same position of the processed film 500 in the film width direction TD. However, the processing devices 711 and 712 are provided so as to be able to form the uneven portion 110 at different positions of the unprocessed film 500 in the film longitudinal direction MD. Therefore, in the long film 100 produced, as shown in FIG. 16, the first uneven portion 110a formed by the processing device 711 and the second uneven portion 110b formed by another processing device 712 are at the same position in the film width direction TD but are at different positions in the film longitudinal direction MD. In this embodiment, an example is given in which one processing device 711 and the other processing device 712 alternately form the uneven portion 110, so that the first uneven portion 110a and the second uneven portion 110b are arranged alternately in the longitudinal direction MD of the film.

[0166] 15, the height control unit 720 includes an irradiation unit 210, an imaging unit 220, and a feedback control unit 730. This height control unit 720 is provided in the same manner as the manufacturing apparatus 400 according to the third embodiment, except that the height control unit 720 includes the feedback control unit 730 instead of the feedback control unit 430. Therefore, the irradiation unit 210 of the height control unit 720 is provided in the same manner as the irradiation unit 210 described in the third embodiment. In addition, the imaging unit 220 of the height control unit 720 is provided in the same manner as the imaging unit 220 described in the third embodiment.

[0167] The feedback control unit 730 includes an area measurement unit 231 and a condition control unit 733. The feedback control unit 730 may further include a height calculation unit 232. The area measurement unit 231 and the height calculation unit 232 are provided in the same manner as the area measurement unit 231 and the height calculation unit 232 described in the third embodiment.

[0168] The condition control unit 733 is provided in the same manner as the condition control unit 433 described in the third embodiment, except that it is provided to control the conditions for forming the unevenness portions 110a and 110b by each of the multiple processing devices 711 and 712 included in the unevenness forming unit 710. Therefore, the condition control unit 733 is provided to take in information on the area of ​​the shadow area measured by the area measurement unit 231, and to control the conditions for forming the unevenness portions using the multiple processing devices 711 and 712 in the unevenness forming unit 710 based on the area of ​​the shadow area. Specifically, the condition control unit 733 is provided to control the conditions for forming the unevenness portions using the multiple processing devices 711 and 712 in the unevenness forming unit 710 so that the area of ​​the shadow area falls within a predetermined range corresponding to the desired representative height required for the unevenness portions of the long film 100.

[0169] The condition control unit 733 preferably controls the conditions for forming the uneven portion so that the areas of the shadow areas corresponding to the uneven portions formed by the multiple processing devices 711 and 712 are the same. Therefore, the condition control unit 733 is preferably capable of controlling the conditions for forming the uneven portion 110a by the processing device 711 so that the area of ​​the shadow area corresponding to the uneven portion 110a formed by the processing device 711 falls within a predetermined range. In addition, the condition control unit 733 is preferably capable of controlling the conditions for forming the uneven portion 110b by the processing device 711 so that the area of ​​the shadow area corresponding to the uneven portion 110b formed by another processing device 712 falls within a predetermined range. And, it is preferable that the predetermined range in which the area of ​​the shadow area corresponding to the uneven portion 110a should fall is the same as the predetermined range in which the area of ​​the shadow area corresponding to the uneven portion 110b should fall.

[0170] The manufacturing method for the long film 100 using the above-mentioned manufacturing apparatus 700 includes a step (I) of forming an uneven portion in the unprocessed film 500 to obtain the long film 100, and a step (II) of controlling the height of the uneven portion formed in step (I).

[0171] Specifically, as in the manufacturing method according to the third embodiment, as shown in FIG. 15, a long unprocessed film 500 is continuously transported in the film longitudinal direction MD, and the unprocessed film 500 is supplied to the manufacturing apparatus 700. When the unprocessed film 500 is supplied to the manufacturing apparatus 700, the unevenness forming section 710 performs a step (I) of forming unevenness portions 110a and 110b on the unprocessed film 500. In this embodiment, as shown in FIG. 15, the unevenness forming section 710 includes a plurality of processing devices 711 and 712, and the unevenness portions 110a and 110b are formed at different positions in the film longitudinal direction of the unprocessed film 500 using the processing devices 711 and 712. In this embodiment, as shown in FIG. 16, the processing devices 711 and 712 alternately form the unevenness portions 110a and 110b at the end portions in the film width direction TD, and thus a long film 100 in which the unevenness portions 110a and 110b are alternately arranged in the film longitudinal direction MD is obtained. The long film 100 thus obtained is sent to the height control section 720 .

[0172] When the long film 100 is sent to the height control section 720, the height control section 720 performs step (II) of controlling the height of the uneven portion formed in step (I). This step (II) includes step (II-1) of vertically irradiating the long film 100 with parallel light L; step (II-2) of photographing the parallel light L transmitted through the long film 100 to obtain an image; step (II-3) of measuring the area of ​​the shadow area from the image; and step (II-4) of controlling the conditions for forming the uneven portion in step (I) based on the area of ​​the shadow area. In the manufacturing method according to the fifth embodiment, steps (II-1), (II-2) and (II-3) can be performed in the same manner as in the third embodiment. When steps (II-1), (II-2) and (II-3) are performed, as in the third embodiment, information on the area of ​​the shadow area measured with a measurement unit area 240 (see FIG. 10) set at least in the film longitudinal direction MD as one unit is obtained in the area measurement unit 231. As in the third embodiment, the area of ​​the measured shadow area corresponds to the total area of ​​each of the uneven portions 110a and 110b forming one knurl portion 120. The information on the area of ​​the shadow area measured in this manner is sent to the condition control unit 733 and the height calculation unit 232.

[0173] When the condition control unit 733 receives the information on the area of ​​the shadow area from the area measurement unit 231, the condition control unit 733 performs a step (II-4) of controlling the conditions for forming the uneven portion in the step (I) based on the area of ​​the shadow area. This step (II-4) can be performed in the same manner as the step (II-4) described in the third embodiment, except that the condition for forming the uneven portion 110a and 110b by each of the multiple processing devices 711 and 712 included in the unevenness forming unit 710 is controlled. Therefore, the condition control unit 733 can control the conditions for forming the uneven portion 110a by the processing device 711 so that the area of ​​the shadow area corresponding to the uneven portion 110a formed by the processing device 711 falls within a predetermined range. In addition, the condition control unit 733 can control the conditions for forming the uneven portion 110b by the processing device 711 so that the area of ​​the shadow area corresponding to the uneven portion 110b formed by another processing device 712 falls within a predetermined range. At this time, it is preferable that the predetermined range in which the area of ​​the shadow area corresponding to the uneven portion 110a should fall and the predetermined range in which the area of ​​the shadow area corresponding to the uneven portion 110b should fall are set to be the same. When the predetermined range is set in this way, the step (II-4) can include controlling the conditions for forming the uneven portions 110a and 110b in the step (I) so that the areas of the shadow areas corresponding to the uneven portions 110a and 110b formed by the multiple processing devices 711 and 712 fall within the same range. In this case, the uneven portions 110a and 110b having the same desired representative height can be formed by using the multiple processing devices 711 and 712 while stably forming the uneven portions 110a and 110b using the processing devices 711 and 712.

[0174] When the feedback control unit 730 has the height calculation unit 232, the height calculation unit 232 may perform step (III) of taking in the area information of the shadow area sent from the area measurement unit 231 and calculating the representative height of the uneven portions 110a and 110b from the area of ​​the shadow area taken in, as in the manufacturing method according to the third embodiment. Usually, the representative height of the uneven portions 110a and 110b measured in this manner is output to an output device (not shown) connected to the manufacturing apparatus 700.

[0175] According to the above-described manufacturing method, the formation of the concave and convex portions 110a and 110b can be stabilized, and therefore, it is possible to rapidly manufacture the long film 100. Moreover, according to the manufacturing method of this embodiment, it is possible to manufacture the same long film 100 as in the manufacturing method using a single processing device 411 as in the third embodiment, and it is possible to obtain the same advantages as those described in the third embodiment.

[0176] [7. Example of changes] The present invention is not limited to the above-described embodiment, and may be further modified and implemented. For example, the method of controlling the conditions for forming the uneven portion when changing the area of ​​the shadow area is not limited to the above, and other methods may be adopted. As a specific example, when the measurement unit area is divided and set in both the film longitudinal direction MD and the film width direction TD as in the manufacturing method according to the fourth embodiment, the start point of irradiation of the laser light may be controlled as a condition for forming the uneven portion. In general, the start point of irradiation where the laser light starts to hit the unprocessed film can form the uneven portion higher than other points. Therefore, the start point of irradiation may be controlled to move to an area where the representative height is desired to be high among a plurality of measurement unit areas arranged in the film width direction, and the uneven portion in that area may be controlled to be high.

[0177] In the fifth embodiment described above, an example was shown in which the uneven portion was formed using a plurality of processing devices when the measurement unit area was set by dividing the film in the longitudinal direction as in the third embodiment. For example, this may be further modified to form the uneven portion using a plurality of processing devices when the measurement unit area was set by dividing the film in both the longitudinal direction and the width direction as in the fourth embodiment.

[0178] Furthermore, in the above embodiment, as shown in Fig. 2, a long film having concave-convex portions on only one side has been described as an example, but the above-mentioned measurement method and manufacturing method may be applied to a long film having concave-convex portions on both sides. When the representative height of the concave-convex portions of a long film having concave-convex portions on both sides is measured by the above-mentioned measurement method, it is usually possible to measure the total representative height of the concave-convex portions on both sides of the measurement unit area.

[0179] In the above-described embodiment, an example was shown in which a film unwound from the film roll 150 or 510 was supplied to a measuring device or a manufacturing device, but a film manufactured in another appropriate manufacturing device may be supplied to the measuring device or manufacturing device according to the above-described embodiment without going through a process of winding the film into a roll. For example, in the third or fourth embodiment, the long resin film 500 manufactured by the extrusion molding device may be supplied to the manufacturing device 600 or 700 without being wound up.

[0180] Furthermore, in the above-mentioned embodiments, the concave-convex portion has a linear planar shape, but the concave-convex portion may have a planar shape other than a linear shape. Furthermore, even if the concave-convex portion has a linear planar shape, the planar shape of the knurl portion formed by the entire continuous linear concave-convex portion may be a shape other than a closed ring shape. EXAMPLES

[0181] The present invention will be specifically described below with reference to examples. However, the present invention is not limited to the examples shown below, and can be modified as desired without departing from the scope of the claims of the present invention and the scope of equivalents thereto. In the following description, "%" and "parts" expressing amounts are by weight unless otherwise specified. Furthermore, the operations described below were carried out in the atmosphere at room temperature and normal pressure (23°C and 1 atm) unless otherwise specified.

[0182] [Evaluation method] [Method of measuring the height of uneven parts] The height of the projections and recesses on the long film was measured using a three-dimensional surface profiler (Zygo's "NewView5000").

[0183] [Example 1] [Production of Base Layer] Pellets of a cyclic olefin resin (ZEONOR manufactured by Zeon Corporation; glass transition temperature 135° C.) were dried for 2 hours at 70° C. using a hot air dryer with air circulation. The dried pellets were fed to a T-die type film melt extrusion molding machine having a resin melt kneader equipped with a 65 mmφ screw, and extrusion molding was carried out under molding conditions of a molten resin temperature of 270° C. and a T-die width of 1700 mm to produce a long substrate layer (thickness 50 μm, width 1500 mm, length 4000 m).

[0184] [Production of pre-processed film (formation of easy-adhesion layer)] A water dispersion of a polyether-based polyurethane (Dai-ichi Kogyo Seiyaku Co., Ltd.'s "Superflex 870") was mixed with 100 parts of polyurethane, 15 parts of an epoxy compound (Nagase ChemteX Corporation's "Denacol EX313") as a crosslinking agent, 8 parts of an aqueous dispersion of silica particles (Nissan Chemical Industries, Ltd.'s "Snowtex MP1040"; average particle size 120 nm) as a lubricant, and 8 parts of an aqueous dispersion of silica particles (Nissan Chemical Industries, Ltd.'s "Snowtex XL"; average particle size 50 nm) as a lubricant, 0.5% by weight of an acetylene-based surfactant (Air Products and Chemicals, Inc.'s "Surfynol 440") as a wetting agent relative to the total solid content, and water to obtain an aqueous dispersion of a liquid water-based urethane resin with a solid content of 2%.

[0185] The aqueous dispersion of the aqueous urethane resin was applied to one side of the base layer by a reverse roll method so that the thickness after drying would be 45 nm, and then dried at 90° C. As a result, an easy-adhesion layer was formed on one side of the base layer, and a pre-processing film having a multilayer structure including the base layer and the easy-adhesion layer was obtained.

[0186] [Formation of uneven parts] The unprocessed film was transported in the longitudinal direction at a speed of 30 m / min. Then, the surface of the easily adhesive layer side at both left and right ends in the film width direction of the transported unprocessed film was irradiated with laser light to form multiple concave and convex portions, thereby obtaining a long film. 2A laser light irradiation device (Coherent Corporation's "J3 Series", laser wavelength 9.4 μm) was used. The irradiation output of the laser light was set to 55%. The laser light was irradiated while moving the laser light irradiation point with a galvano scanner at a moving speed of 7000 mm / s so as to draw the desired planar shape of the unevenness. The irradiation of the laser light formed unevenness having a linear planar shape.

[0187] FIG. 17 is a schematic plan view showing the planar shape of the concave-convex portion 1 formed in Example 1. In FIG. 17, the coordinates of the film longitudinal direction MD and the film width direction TD of the long film are shown to show the dimensions of the concave-convex portion 1. The units of the numerical values ​​of these coordinates are millimeters. The planar shape of the concave-convex portion 1 was the shape shown in FIG. 17. In the planar shape of the concave-convex portion 1 shown in FIG. 17, the corners A shown surrounded by a dashed line all had an angle of 90°. In addition, in the planar shape of the concave-convex portion 1, the angle of the corners X other than the corners A was 135°. The dimension L of the knurl portion formed by the entire continuous linear concave-convex portion 1 was MD and L TD is the length L in the film longitudinal direction MD MD is 1.2 mm, and the length L in the film width direction TD TD The pitch of the knurled portions in the longitudinal direction MD of the film was 4.2 mm. When the height of the uneven portion 1 was actually measured by a three-dimensional surface profiler, the average height of the corners A and X of the uneven portion 1 was 10 μm.

[0188] The long film having the concave and convex portions formed as described above was further transported in the longitudinal direction and 4000 m was wound in the longitudinal direction around a core having a diameter of 6 inches at a winding tension of 120 N to obtain a film roll.

[0189] [Measurement of the height of the knurled part] An irradiation device equipped with a light source ("MTI-45" manufactured by Moritex) and a lens ("MTI-120" manufactured by Moritex) was installed on one side of the film transport path. This irradiation device was set up so that the parallel light obtained by transmitting the light emitted from the light source through the lens could be irradiated perpendicularly onto the long film transported along the film transport path.

[0190] A double-sided telecentric lens barrel ("LSTL036T-F" manufactured by Myutron Co., Ltd.) equipped with an object-side telecentric lens, an aperture, and an image-side telecentric lens was prepared, and a line scan camera ("VT-3K7X-E250A-32" manufactured by Nippon Viewerx Co., Ltd.) was connected to prepare a photographing device. This photographing device was installed on the other side of the film transport path (i.e., the opposite side to the irradiation device). In this case, the photographing device was installed so that both the object-side telecentric lens and the image-side telecentric lens were perpendicular to the parallel light, and the light beam of the parallel light irradiated from the irradiation device was parallel to the optical axis of the telecentric lens.

[0191] The film roll was placed on a conveyor, and the long film was unwound and conveyed in the long direction at a speed of 30 m / min. The conveyed long film was passed through the film conveying path between the irradiation device and the photographing device. Parallel light was irradiated from the irradiation device to the part of the long film where the unevenness was formed, and the parallel light that passed through the long film was photographed by the photographing device to obtain an image. The obtained image was subjected to binarization processing based on brightness to identify a relatively dark shadow area as an area corresponding to the unevenness. A measurement unit area including one knurl part was set, and the number of pixels in the shadow area of ​​the measurement unit area was counted. The number of pixels in the shadow area was counted in multiple measurement unit areas to obtain the average number of pixels in the shadow area, which was 34,000 pixels. This average number of pixels represents the area of ​​the area where the parallel light could not pass straight through the long film, and corresponds to the area of ​​the unevenness as viewed from the thickness direction.

[0192] [Example 2] A long film was produced and evaluated in the same manner as in Example 1, except that the irradiation output of the laser light used to form the uneven portion was changed to 42%. The average height of the corners of the uneven portion was measured with a three-dimensional surface profiler and found to be 3 μm. In addition, the average number of pixels in the shadow area corresponding to the uneven portion measured using an irradiation device and a photographing device was 11,000 pixels.

[0193] [Example 3] A long film was produced and evaluated in the same manner as in Example 1, except that the irradiation output of the laser light used to form the uneven portion was changed to 46%. The average height of the corners of the uneven portion was measured using a three-dimensional surface profiler and found to be 5 μm. The average pixel count of the shadow area corresponding to the uneven portion measured using an irradiation device and a photographing device was 16,000 pixels.

[0194] [Example 4] A long film was produced and evaluated in the same manner as in Example 1, except that the irradiation output of the laser light used to form the uneven portion was changed to 64%. The average height of the corners of the uneven portion was measured using a three-dimensional surface profiler and found to be 14 μm. The average pixel count of the shadow area corresponding to the uneven portion measured using an irradiation device and a photographing device was 47,000 pixels.

[0195] [result] FIG. 18 shows the relationship between the actual measured value of the average height of the corners of the uneven portion measured in the above-mentioned embodiment and the average number of pixels of the shadow area corresponding to the uneven portion. The dashed line in FIG. 18 represents an approximation line created by the least squares method from the results of the embodiment. As can be seen from FIG. 18, the actual measured value of the average height of the corners of the uneven portion and the average number of pixels of the shadow area corresponding to the uneven portion are correlated and have a proportional relationship. Therefore, the representative height of the uneven portion can be measured from the area of ​​the shadow area represented by the average number of pixels, and in this case, the approximation line shown in FIG. 18 can be used as a calibration curve. And, since there is a correlation between the area of ​​the shadow area and the representative height of the uneven portion, feedback control using the area of ​​the shadow area is possible. [Explanation of symbols]

[0196] 100 Long Film 100U side 110 Uneven part 110a, 110b uneven part 111 Convex 112 Recess 120 Naru Department 130 Corner 140 Straight section 150 film rolls 160 rolls 200 Measuring Equipment 210 Irradiation unit 211 Light source 212 Collimator lens 220 Photography Department 221 Camera 222 Object-side telecentric lens 223 Image side telecentric lens 224 Aperture 230 Height measurement unit 231 Area measurement section 232 Height Calculation Unit 240 Measurement Units Area 300 Measuring Equipment 330 Height measurement unit 331 Area calculation part 332 Height Calculation Unit 341~344 Measurement unit area 400 Manufacturing equipment 410 Unevenness forming part 411 Processing equipment 420 Height control section 430 Feedback control section 433 Condition Control Section 500 Resin Film 510 film roll 600 Manufacturing equipment 620 Height control section 630 Feedback control section 633 Condition Control Section 700 Manufacturing equipment 710 Unevenness forming part 711, 712 Processing equipment 720 Height control section 730 Feedback control section 733 Condition Control Section

Claims

1. A method for measuring the height of unevenness formed on a long film, comprising: A step (i) of vertically irradiating the long film with parallel light; (ii) capturing an image of the parallel light transmitted through the long film; (iii) measuring the height of the uneven portion based on the image; The step (iii) A step (iii-1) of measuring an area of ​​an area where the parallel light could not pass straight through the long film from the image; A step (iii-2) of calculating the height of the uneven portion from the area; A measurement method including:

2. The measurement method according to claim 1 , wherein the uneven portion is formed at an end portion in the width direction of the film and aligned in the longitudinal direction of the film.

3. The measurement method according to claim 1 or 2, wherein the step (iii-1) includes measuring the area of ​​the area in which the parallel light cannot pass straight through the long film, with a region set by dividing at least the film longitudinal direction as one unit.

4. The measurement method according to any one of claims 1 to 3, wherein the step (iii-1) includes measuring the area of ​​the area in which the parallel light cannot pass straight through the long film, with a region set by dividing the area in both the longitudinal direction and the width direction of the film as one unit.

5. The measurement method according to any one of claims 1 to 4, wherein the step (ii) includes photographing the parallel light transmitted through the long film by a camera provided on the opposite side of the long film to the side on which the parallel light is irradiated.

6. The measurement method according to claim 5 , wherein the camera is a line scan camera.

7. The measurement method according to any one of claims 1 to 6, wherein the step (ii) includes photographing the parallel light transmitted through the long film after it has further passed through a telecentric lens.

8. A method for producing a long film having an uneven portion, comprising: The manufacturing method comprises: A step (I) of forming a concave-convex portion on a resin film to obtain the long film; A step (II) of controlling the height of the uneven portion formed in the step (I); The step (II) A step (II-1) of vertically irradiating the long film with parallel light; A step (II-2) of photographing the parallel light transmitted through the long film to obtain an image; A step (II-3) of measuring an area of ​​an area where the parallel light could not pass straight through the long film from the image; and a step (II-4) of controlling conditions for forming the concave-convex portion in the step (I) based on the area of ​​the area.

9. The method for producing a long film according to claim 8, wherein the step (II-4) includes controlling conditions for forming the uneven portion in the step (I) so that the area of ​​the area falls within a predetermined range.

10. The step (II-3) includes measuring the area of ​​the area where the parallel light cannot pass straight through the long film, with each area set by dividing at least the film longitudinal direction as a unit, The method for producing a long film according to claim 8 or 9, wherein the step (II-4) includes controlling the conditions for forming the uneven portion in the step (I) so that the area of ​​the area measured in the unit falls within a predetermined range.

11. The step (II-3) includes measuring the area of ​​the area in which the parallel light cannot pass straight through the long film, with each area set in both the film longitudinal direction and the film width direction as a unit, The method for producing a long film according to any one of claims 8 to 10, wherein the step (II-4) includes controlling conditions for forming the uneven portion in the step (I) so that the area of ​​the area measured in the unit falls within a predetermined range.

12. The step (I) includes forming the concave-convex portions at different positions in the longitudinal direction of the film using a plurality of processing devices, The method for producing a long film described in any one of claims 8 to 11, wherein the step (II-4) includes controlling the conditions for forming the uneven portion in the step (I) so that the areas corresponding to the uneven portions formed by the multiple processing devices fall within the same range.

13. The method for producing a long film according to any one of claims 8 to 12, further comprising a step (III) of calculating a height of the uneven portion from the area of ​​the area measured in the step (II-3).

14. The method for producing a long film according to any one of claims 8 to 13, wherein the height of the uneven portion is 1 µm or more and 25 µm or less.

15. The method for producing a long film according to any one of claims 8 to 14, wherein the step (I) comprises forming the uneven portion by processing using laser light or heat.

16. The method for producing a long film according to any one of claims 8 to 15, wherein the step (I) includes forming a plurality of the uneven portions at the ends of the film in the width direction, side by side in the longitudinal direction of the film.

17. The method for producing a long film according to any one of claims 8 to 16, wherein the step (II-2) includes photographing the parallel light transmitted through the long film by a camera provided on the opposite side of the long film from the side on which the parallel light is irradiated.

18. The method for producing a long film according to claim 17, wherein the camera is a line scan camera.

19. The method for producing a long film according to any one of claims 8 to 18, wherein the step (II-2) includes photographing the parallel light transmitted through the long film after it has further passed through a telecentric lens.

20. A device for measuring the height of an uneven portion formed on a long length film, which is used in the method for measuring the height of an uneven portion formed on the long length film according to any one of claims 1 to 7; An irradiation unit capable of irradiating the long film with parallel light; an imaging unit capable of capturing an image by capturing the parallel light transmitted through the long film; a height measuring unit capable of measuring the height of the uneven portion based on the image; The height measuring unit is an area measuring unit capable of measuring an area of ​​an area where the parallel light was not able to pass straight through the long film from the image; a height calculation unit capable of calculating a height of the uneven portion from the area; A measuring device comprising:

21. An apparatus for producing a long film having a concave-convex portion, comprising: The manufacturing apparatus comprises: a concave-convex forming unit capable of forming a concave-convex portion on a resin film to obtain the long film; a height control unit capable of controlling the height of the uneven portion formed by the unevenness forming unit; The height control section, An irradiation unit capable of irradiating the long film with parallel light; an imaging unit capable of capturing an image by capturing the parallel light transmitted through the long film; an area measuring unit capable of measuring an area of ​​an area where the parallel light was not able to pass straight through the long film from the image; a condition control unit capable of controlling conditions for forming the uneven portion in the unevenness forming unit based on the surface area of ​​the area.

Images