JP2012006177A - Method of manufacturing mold roll, mold roll and method of manufacturing optical sheet - Google Patents

Abstract

The present invention relates to a mold roll for an optical sheet, and provides a mold roll manufacturing method that can reduce the number of exchanges without exchanging a cutting tool even for a wide-width mold roll.
A method of manufacturing a mold roll for forming a concavo-convex portion of an optical sheet having a concavo-convex shape, in which a roll base 21 having a surface to be processed is rotated and a cutting tool 30 is used to rotate the optical sheet. Including a step of forming grooves corresponding to the unevenness, wherein the side clearance angle of the cutting tool is set to 2 degrees or more and 5 degrees or less.
[Selection] Figure 5

Description

  The present invention relates to a method for manufacturing a mold roll used in manufacturing an optical sheet having a fine uneven shape formed on the surface, a mold roll manufactured by the manufacturing method, and an optical sheet using the mold roll. It relates to a manufacturing method.

  An image display device that emits an image to an observer, such as a plasma television or a liquid crystal display device, has an image light source and various functions for improving the quality of the image light from the image light source and transmitting it to the observer And an optical sheet having a layer.

  Such an optical sheet may be provided with a layer (sheet) having a fine uneven shape on the surface thereof. Thus, in order to manufacture the sheet | seat which has an unevenness | corrugation on the surface, the die roll which equips the surface with the unevenness | corrugation which can transfer this corresponding to this unevenness | corrugation is used.

  Patent Document 1 discloses a method for manufacturing a mold roll applied to an optical sheet. Here, a technique related to a bite shape for manufacturing a mold for manufacturing an optical sheet having an uneven shape capable of suppressing generation of point defects and linear defects is described.

JP 2003-21457 A

  It is not necessary to form several such irregularities on the roll, and very many irregularities must be formed on the roll. And from a viewpoint of ensuring the quality of the optical sheet manufactured from here, the countless uneven shape needs to be as uniform as possible in any part on the roll.

  However, in the conventional mold roll manufacturing method for optical sheet manufacturing, although the shape of the cutting tool corresponding to the cross-sectional shape of the unevenness is taken into consideration, consideration is given to the long life of the cutting tool and the long and uniform cutting. There was nothing that has been done. In order to form such fine irregularities requiring a lot of precision (long when one groove is formed in a spiral shape), the cutting tool has to be replaced halfway.

  Replacing the cutting tool on the way may deteriorate the manufacturing efficiency of the mold roll or decrease the accuracy at the front and rear portions due to the replacement, and is to be avoided if possible.

  Therefore, the present invention relates to a mold roll for an optical sheet, and a mold roll manufacturing method capable of reducing the number of replacements without replacing the cutting tool even if the roll is wide, and the manufacturing method. It is an object of the present invention to provide a mold roll according to the above and a method for producing an optical sheet produced thereby.

  The present invention will be described below. In order to facilitate understanding of the present invention, reference numerals in the accompanying drawings are appended in parentheses, but the present invention is not limited to the illustrated embodiment.

  The invention according to claim 1 is a method of manufacturing a mold roll (20) for forming a concave and convex portion of an optical sheet (10) having a concave and convex shape, the roll base having a work layer formed on the surface ( 21) is rotated, and the grooves (23, 23,...) Corresponding to the irregularities of the optical sheet are formed by the cutting tool (30), and the lateral clearance angle of the cutting tool is set to 2 degrees or more and 5 degrees or less. It is the manufacturing method of the metal mold | die roll characterized by the above-mentioned.

  The invention according to claim 2 is the method of manufacturing a mold roll according to claim 1, wherein the roll base (21) has a diameter of 300 mm or more and 500 mm or less, and the rotation speed of the roll base is 300 rpm or more and 600 rpm or less. And forming grooves.

  Invention of Claim 3 is a manufacturing method of the metal mold | die roll of Claim 1 or 2, The cutting direction of the cutting tool (30) is a direction orthogonal to the axial direction of a roll base | substrate rotating shaft, It is characterized by the above-mentioned. And

  Invention of Claim 4 is a manufacturing method of the metal mold | die as described in any one of Claims 1-3, The cutting speed of the cutting tool (30) is 2 micrometers / rev or more and 5 micrometers / rev or less. It is characterized by that.

  According to a fifth aspect of the present invention, in the mold roll manufacturing method according to any one of the first to fourth aspects, the roll base is rotated once in a posture in which the cutting tool (30) has reached the cutting depth. After the above, the cutting tool is retracted.

  Invention of Claim 6 is a manufacturing method of the metal mold | die roll as described in any one of Claims 1-5, The bottom part of the uneven | corrugated recessed part which should be formed in a roll base | substrate (21), and a convex part The cutting tool is fed at a pitch that is half the pitch of the recess so as to alternately cut the outer peripheral portion.

  Invention of Claim 7 is the metal mold | die roll manufactured by the manufacturing method of the metal mold | die roll as described in any one of Claims 1-6.

  According to an eighth aspect of the present invention, there is provided a step of filling a photocurable material between the mold roll (20) according to the seventh aspect and the base material (21), and light in the filled state. It is a manufacturing method of the optical sheet including the process of irradiating light to a curable material and hardening a photocurable material.

  ADVANTAGE OF THE INVENTION According to this invention, the die roll of an optical sheet can be manufactured, without changing the cutting tool or suppressing the frequency | count of exchange. That is, it is possible to improve the efficiency and accuracy of manufacturing one mold roll and to manufacture the uneven shape of the optical sheet that is the final product with high accuracy.

It is the figure which showed a part of cross section of the optical sheet concerning one embodiment schematically. It is the figure which expanded a part of FIG. It is the figure which showed the external appearance of the metal mold | die roll roughly. It is the figure which expanded and showed the annular protrusion and groove | channel of the metal mold | die roll. It is the figure which showed the shape of the cutting tool roughly. It is a figure explaining the manufacturing method of a metal mold | die roll. This is a method for producing an optical sheet.

  The above-described operation and gain of the present invention will be clarified from embodiments for carrying out the invention described below. Hereinafter, the present invention will be described based on embodiments shown in the drawings. However, the present invention is not limited to these embodiments.

First, the optical sheet 10 according to one embodiment will be described. This is an optical sheet according to one form of an object manufactured by a mold roll described later.
FIG. 1 is a diagram schematically showing a layer structure of a part of a cross section of the optical sheet 10. In FIG. 1, some repetitive symbols are omitted for the sake of clarity (the same applies to the following drawings). The optical sheet 10 is a sheet-like member that is provided on the viewer side of the video light source in the video display device and can appropriately shield the light (so-called external light) irradiated from the viewer side and improve the contrast. is there.

  The optical sheet 10 includes a base material layer 11 and an optical functional layer 12 formed on the base material layer 11. The base material layer 11 and the optical function layer 12 will be described below.

  The base material layer 11 is a layer serving as a base material for forming the optical functional layer 12 described in detail later. The base material layer 11 is preferably composed of a material mainly composed of polyethylene terephthalate (PET). When the base material layer 11 has PET as a main component, the base material layer 11 may contain other resins. Various additives may be added as appropriate. Examples of general additives include phenol-based antioxidants, lactone-based stabilizers, and the like. Here, “main component” means that the PET is contained in an amount of 50% by mass or more with respect to the entire material forming the base material layer (hereinafter the same).

However, the main component of the material constituting the base material layer 11 is not necessarily PET, and other materials may be used. Examples thereof include polybutylene terephthalate, polyethylene naphthalate, terephthalic acid-isophthalic acid-ethylene glycol copolymer, polyester resins such as terephthalic acid-cyclohexanedimethanol-ethylene glycol copolymer, and polyamide resins such as nylon 6. , Polyolefin resins such as polypropylene and polymethylpentene, acrylic resins such as polymethyl methacrylate, styrene resins such as polystyrene and styrene-acrylonitrile copolymer, cellulose resins such as triacetyl cellulose, imide resins and polycarbonate resins Etc. Moreover, you may add additives, such as a ultraviolet absorber, a filler, a plasticizer, an antistatic agent, in these resins suitably as needed.
In addition to performance, from the viewpoints of mass productivity, price, availability, etc., it is preferable that the base material layer 11 is composed of a resin mainly composed of PET.

  The optical functional layer 12 is a layer having a function of appropriately absorbing stray light and external light while controlling the optical path of the image light from the image light source side. The optical functional layer 12 has a shape that has the cross section shown in FIG. 1 and extends to the back / near side of the drawing. That is, in the cross section shown in FIG. 1, the light transmissive portions 13, 13,. ... Are formed. FIG. 2 shows an enlarged view of one light absorbing portion 14 and the light transmitting portions 13 and 13 adjacent to the light absorbing portion 14 in the optical sheet 10 shown in FIG.

  The light transmissive portions 13, 13,... Are portions that function as light transmissive portions, and in the cross section shown in FIGS. An element having a substantially trapezoidal cross section with a bottom. The light transmitting portions 13, 13,... Are arranged in parallel at a predetermined interval along the sheet surface, and a recess 13a having a substantially trapezoidal cross section is formed therebetween. The concave portion 13a has a trapezoidal cross section having a lower base on the upper base side of the light transmitting portion 13 and an upper base on the lower base side of the light transmitting portion 13, and is filled with necessary materials described later. Thus, the light absorbing portion 14 is formed.

  Although the space | interval (space | interval of the light transmissive part 13 and the adjacent light transmissive part 13 and a pitch) where the light transmissive parts 13, 13, ... are parallel is not specifically limited, It is preferable that they are 30 micrometers or more and 100 micrometers or less.

In FIG. 2, each dimension of the recessed part 13a was represented by AD. In FIG. 2, A is the length of the bottom of the recess 13a. Similarly, B is the length of the upper base, C is the height, and D is the angle between the hypotenuse and the sheet normal. Each of the dimensions A to D is designed to have performance required as an optical sheet, and its value is not particularly limited, but A is preferably 5 μm or more and 20 μm or less. Similarly, B is preferably the same as or smaller than A, 3 μm to 20 μm, C is 50 μm to 150 μm, and D is 0 ° to 5 °.
As will be described later, a mold roll corresponding to each dimension required here is manufactured.

  The light transmission parts 13, 13,... Have a refractive index of Np and have light transparency. .. Can be formed by curing a light transmitting portion constituent composition described later. Details will be described later. The value of the refractive index Np is not particularly limited, but is preferably 1.49 or more and 1.56 or less from the viewpoint of the availability of the applied material.

  Next, the light absorbers 14, 14,... Will be described. The light absorbing portions 14, 14,... Are formed in the recesses 13a, 13a,... Between the light transmitting portions 13, 13,. Therefore, the shape is substantially along the recesses 13a and 13a.

  The light absorbing portions 14, 14,... Are made of a predetermined material having a refractive index Nb that is the same as or smaller than the refractive index Np of the light transmitting portions 13, 13,. The refractive index Np of the light transmission parts 13, 13 ... and the refractive index Nb of the light absorption parts 14, 14, ... satisfy Np≥Nb, so that the light source is incident on the light transmission parts 13, 13, ... under predetermined conditions. Can be appropriately reflected at the interface between the light absorbing portions 14, 14,... And the light transmitting portions 13, 13,. In addition, it is possible to improve the quality of the image by absorbing the external light or part of the stray light without reflecting the light absorption part. The difference in refractive index between Np and Nb is not particularly limited, but is preferably 0 or more and 0.06 or less.

  In this embodiment, the light absorption parts 14, 14,... Have light absorption performance by containing the light absorption particles 16, 16. That is, the concave portions 13a, 13a,... Are filled with a binder (light absorbing portion constituting composition) in which the light absorbing particles 16, 16,. The materials and methods for forming the light absorbing portions 14, 14,... Will be described in detail later.

  The means for absorbing light is not limited to the method using light absorbing particles as in this embodiment. In addition, for example, the entire light absorbing portion can be colored with a pigment or a dye.

  According to such an optical sheet 10, it is possible to appropriately shield outside light. FIG. 1 schematically shows an example of an optical path of external light incident on the optical sheet 10. In this description, the upper side of FIG. That is, as shown in FIG. 1, external light L <b> 1 incident on the optical sheet 10 at a predetermined angle is absorbed by the light absorbing unit 14 while being transmitted through the optical sheet 10. Thereby, contrast can be improved.

  Next, the mold roll 20 for forming the unevenness | corrugation (recessed part 13a, 13a, ...) of the optical function layer 12 among the above optical sheets 10 is demonstrated. FIG. 3 is a perspective view schematically showing the appearance of the mold roll 20. 4 is an enlarged view of the cross-sections of the annular protrusions 22 and the grooves 23, 23,... Formed on the outer peripheral surface of the mold roll 20 shown in FIG. The cross section is a cross section orthogonal to the direction in which the annular protrusion 22 and the groove 23 extend.

  As shown in FIG. 3, the mold roll 20 is a so-called cylindrical roll, and a plurality of annular protrusions 22, 22,... Protruding from the outer peripheral surface of the cylindrical roll base 21, and the annular protrusions 22, 22. ,... Have grooves 23, 23,. Here, the annular protrusions 22, 22,... And the grooves 23, 23,... Are provided so as to extend in the circumferential direction of the mold roll 20, and are further arranged in parallel in the width direction (roll rotation axis direction). . Further details are as follows.

The roll base 21 has a base and a layer to be processed laminated on the outer surface of the base.
The base is a part for securing the rigidity of the roll base 21 and constitutes most of the roll base 21. From this point of view, the base is preferably made of an iron-based material for mechanical structure. Further, from the viewpoint of reducing the weight while ensuring the necessary rigidity, the base body may have a cylindrical shape with bottoms on both sides. Further, it is general to have a double structure so that cold water, hot water, steam or high-temperature oil can be circulated inside the roll base so that the temperature of the roll base surface can be adjusted.
On the other hand, the layer to be processed is a layer laminated so as to be coated on the outer surface of the substrate. Since the material of the substrate is selected from the viewpoint of structure as described above, it is often difficult to process. Therefore, since only the surface of the roll base 21 is actually processed, a layer to be processed that is relatively easy to process is provided in the processed portion. Therefore, the layer to be processed is preferably a plating layer made of a material that can be easily processed, such as a copper plating layer or a nickel plating layer. The thickness of the layer to be processed is determined by the shape to be processed due to its nature. For example, the thickness of the copper plating layer is not a problem as long as it is equal to or higher than the required shape, but is usually 0.3 mm to 1.0 mm.

  The annular protrusions 22, 22,... And the grooves 23, 23,... Have shapes corresponding to the light transmitting portions 13 and the recessed portions 13a of the optical function layer 12, as can be seen from comparing FIG. 4 with FIGS. It has become. That is, the annular protrusion 22 has the groove shape of the recess 13 a, and the groove 23 has the light transmitting portion 13 shape. Accordingly, A to D shown in FIG. 2 have dimensions corresponding to A 'to D' in FIG. However, it goes without saying that A to D in FIG. 2 do not necessarily have the same dimensions as A ′ to D ′ in FIG. 4 in consideration of expansion and contraction during molding of the material constituting the light transmission portion.

  As can be seen from FIG. 1 and FIG. 2, in the mold roll for forming fine irregularities on the optical sheet, the irregularities themselves are very fine, but the irregularities extend in the circumferential direction of the mold roll, It is densely formed so as to be arranged over the entire length of the mold roll in the width direction (roll rotation axis direction). Moreover, since it is an optical member, it is necessary to ensure sufficient unevenness accuracy. Therefore, when manufacturing a die roll, it is necessary to manufacture it efficiently for a long time while maintaining accuracy. Hereinafter, a method for manufacturing the mold roll 20 will be described.

  A roll substrate on which the layers to be processed are laminated is prepared, and this is rotated by a roll rotation shaft. First, as a pre-processing for obtaining a reference surface, mirror processing is performed by a predetermined cutting tool (R bite) with a necessary cutting depth and feed. The R bit is a bit having a circular arc at the tip, and a diamond having a curvature radius of 2 mm to 10 mm is often used. The feed pitch is generally 0.1 mm to 0.2 mm. Here, the diameter of the roll base is not particularly limited, but is preferably 300 mm or more and 500 mm or less. Thereafter, the groove 23 is formed by a cutting tool while rotating the roll base 21 based on the obtained reference surface. Here, the cutting tool has the following shape. FIG. 5 shows a schematic view of a cutting tip 30 which is a cutting tool used. In FIG. 5, the rake face is denoted by reference numeral 31, the front flank face is denoted by reference numeral 32, and the lateral flank face is denoted by reference numeral 33. 5 (a) is a perspective view, FIG. 5 (b) is a view from the rake face 31 side, FIG. 5 (c) is a view from the front flank face 32 side, and FIG. It is the figure seen from the side.

  The main dimensions of the cutting tip 30 are set so that the shape of the groove 23 can be formed.

Further, the bite angles θa1 and θa2, the lateral clearance angle θb, and the front clearance angle θc shown in FIG. 5 are as follows. Here, the sum of the bite angles θa2 and θa2 is called an apex angle. The apex angle is an angle determined by the shape of the design. In FIG. 5 (b), w is the cutting edge width. The apex angle and the bite tip width are appropriately changed according to the groove to be formed.
The lateral clearance angle θb is set to 2 degrees or more and 5 degrees or less. By setting the side clearance angle to 2 degrees or more, cutting performance of the cutting tip is improved, and a burden on the cutting tip is reduced. Therefore, wear can be reduced, and processing with a single cutting tip can be performed with high accuracy. it can. That is, it is possible to increase the number of cuttings by increasing the depth of the groove 23 or decreasing the pitch. Therefore, the mold roll of the optical sheet can be manufactured without replacing the cutting tip or suppressing the number of replacements. That is, the efficiency and accuracy of manufacturing one mold roll can be improved, and the uneven shape of the optical sheet as the final product can be manufactured with high accuracy. Further, if the side clearance angle θb is larger than 5 degrees, it is necessary to increase the front clearance angle, and there is a concern that the strength of the cutting tip is lowered.
The front clearance angle θc is usually 5 ° or more and 20 ° or less in many cases. Similar to the side clearance angle, if the angle is small, the cutting performance is deteriorated. If it is larger than 20 °, the rigidity of the tip of the cutting tip is lost, and chipping and chipping tend to occur.

  The material of the cutting tip 30 can be appropriately selected depending on the material of the layer to be processed, the processing shape, and the like. Examples thereof include cemented carbide, CBN (cubic boron nitride), diamond and the like. Among these, diamond is preferable from the viewpoint of obtaining high accuracy. There are natural and synthetic diamonds, but there is no particular limitation.

  The rotation speed of the roll substrate is not particularly limited, but is preferably 300 rpm or more and 600 rpm or less. Although it depends on the diameter of the roll base, for example, when the diameter is 400 mm, if it is less than 300 rpm, the cutting speed is slow, so that the burden on the cutting tip becomes large and it becomes impossible to process with high accuracy. 600 rpm is approximately the maximum turning speed of the lathe. Increasing the rotation speed of the roll base tends to cause the roll base to shake, and is preferably about 400 rpm.

  The groove 23 is formed as follows using the cutting tip 30 described above. A schematic diagram is shown in FIG. As shown in FIG. 6A, one groove 23 is formed by the cutting tip 30. Next, the cutting tip 30 is retracted from the groove 23, fed by a half pitch between the grooves 23, 23, and cut to the position of the outer peripheral end surface of the annular protrusion 22 as shown in FIG. Thereby, the outer peripheral end surface of the annular protrusion is formed. Further, after that, the cutting tip 30 is retracted, fed by half a pitch, and the cutting tip 30 is cut so as to form another groove 23 as shown in FIG.

  Here, the cutting is preferably performed in a direction orthogonal to the rotation axis of the roll base. The cutting speed is preferably 2 μm / rotation or more and 5 μm / rotation or less. Furthermore, when the cutting tip (cutting tool) reaches the cutting depth, it is preferable that the cutting tip is retracted after the roll base is rotated one or more times in the same posture. Thereby, it becomes the predetermined cutting depth over the whole circumference direction. When the cutting tip is retracted in less than one revolution, a part that does not reach the predetermined cutting depth in the circumferential direction is formed, and the appearance of the mold roll is poor or the optical sheet is formed by the mold. In addition, the optical performance of the optical sheet may vary.

  As described above, the grooves 23, 23,... Are formed so as to extend in the circumferential direction of the roll base 21 and to be arranged in parallel over the entire length of the roll base 21 in the rotation axis direction. In the mold roll manufacturing method of the present invention, the mold roll can be manufactured without replacing the cutting tip (cutting tool) as described above or by suppressing the number of replacements. In particular, in the shape like the above-described optical functional layer 12 of the present embodiment, the openings (dimensions indicated by A in FIG. 2) are narrow and the depths (dimensions indicated by C in FIG. 2) of the recesses 13a, 13a,. The effect is more remarkable because of the large.

  After the annular protrusions 22, 22,... And the grooves 23, 23,... Are formed by the above cutting, it is preferable to plate the surface of the mold roll with chromium or the like from the viewpoint of preventing corrosion. .

  Next, a method for manufacturing the optical sheet 10 using the mold roll 20 will be described. FIG. 7 shows a schematic diagram. First, the light transmitting portions 13, 13,... Are formed on the base material 11. That is, as can be seen from FIG. 7, the base material 11 ′ to be the base material layer 11 is inserted between the mold roll 20 and the nip roll 41 disposed so as to face the mold roll 20. At this time, the mold roll 20 and the nip roll 41 are rotated as indicated by the arrows in FIG. 7 while supplying the light transmitting portion constituting composition 13 ′ between the base material 11 ′ and the mold roll 20. In this way, the grooves 23, 23,... Formed on the surface of the mold roll 20 are filled with the light transmissive portion constituting composition 13 ′, and the light transmissive portion constituting composition 13 ′ becomes the surface shape of the mold roll 20. It will be along.

  Here, as the light transmission part constituting composition 13 ′, for example, a photocurable resin composition in which a reactive dilution monomer (M1) and a photopolymerization initiator (S1) are blended with a photocurable prepolymer (P1). Is preferably used.

  Examples of the photocurable prepolymer (P1) include epoxy acrylate-based, urethane acrylate-based, polyether acrylate-based, polyester acrylate-based, and polythiol-based prepolymers.

  Examples of the reactive dilution monomer (M1) include vinyl pyrrolidone, 2-ethylhexyl acrylate, β-hydroxy acrylate, and tetrahydrofurfuryl acrylate.

  Examples of the photopolymerization initiator (S1) include hydroxybenzoyl compounds (2-hydroxy-2-methyl-1-phenylpropan-1-one, 1-hydroxycyclohexyl phenyl ketone, benzoin alkyl ether, etc.), benzoyl Formate compounds (such as methylbenzoylformate), thioxanthone compounds (such as isopropylthioxanthone), benzophenones (such as benzophenone), phosphate compounds (1,3,5-trimethylbenzoyldiphenylphosphine oxide, bis (2,4,6-) Trimethylbenzoyl) -phenylphosphine oxide and the like, and benzyldimethyl ketal and the like. Among these, the irradiation device for curing the photocurable resin composition and the curability of the photocurable resin composition can be arbitrarily selected. From the viewpoint of preventing coloring of the light transmitting portions 13, 13,..., 2-hydroxy-2-methyl-1-phenylpropan-1-one, 1-hydroxycyclohexyl phenyl ketone and bis (2, 4, 6-trimethylbenzoyl) -phenylphosphine oxide.

  The amount of the photopolymerization initiator (S1) contained in the photocurable resin composition is based on the total amount of the light transmission part constituent composition (100% by mass) from the viewpoint of curability and cost of the photocurable resin composition. 0.5 mass% or more and 5.0 mass% or less is preferable. Generally, the photoinitiator is substantially colorless after at least polymerization. The photopolymerization initiator may be colored (for example, colored yellow), provided that it is substantially colorless when the light transmissive part constituent composition is cured to form a light transmissive part.

  These photocurable prepolymer (P1), reactive diluent monomer (M1) and photopolymerization initiator (S1) can be used alone or in combination of two or more.

  If necessary, in the composition of the light transmission part, various additives such as silicone additives and rheology control agents can be used to improve the coating film, improve applicability, and release from the mold roll. It is also possible to add a defoaming agent, a release agent, an antistatic agent, an ultraviolet absorber, and the like.

  Light for curing by the light irradiation device 42 is irradiated from the base material 11 'side to the light transmitting portion constituting composition 13' sandwiched between the mold roll 20 and the base material 11 'and filled therein. To do. Thereby, a light transmissive part composition can be hardened and the shape can be fixed. And the base material layer 11 and the shape | molded light transmission part 13, 13, ... are released from the mold roll 20 with the release roll 43. FIG.

  Next, the light absorption parts 14, 14,... Are formed. In order to form the light absorbing portions 14, 14,..., First, the light absorbing portion constituting composition is excessively applied to the recesses 13a, 13a,. Thereafter, the surplus light absorbing portion constituent composition is scraped off with a doctor blade or the like. Then, by irradiating the light absorbing portion constituting composition remaining in the recesses 13a, 13a,... With ultraviolet rays from the light transmitting portion side, the binder 15 contained in the light absorbing portion constituting composition is cured, and the light absorbing portion 14, 14,... Can be formed.

  Although what is used as a binder is not specifically limited, For example, the photocurable resin composition which mix | blended the reactive dilution monomer (M2) and the photoinitiator (S2) with the photocurable prepolymer (P2). Is preferably used.

  Examples of the photocurable prepolymer (P2) include urethane (meth) acrylate, polyester (meth) acrylate, epoxy (meth) acrylate, and butadiene (meth) acrylate.

  Examples of the reactive dilution monomer (M2) include monofunctional monomers such as N-vinyl pyrrolidone, N-vinyl caprolactone, vinyl imidazole, vinyl pyridine, styrene, and other vinyl monomers, lauryl (meth) acrylate, stearyl (meta). ) Acrylate, butoxyethyl (meth) acrylate, ethoxydiethylene glycol (meth) acrylate, methoxytriethylene glycol (meth) acrylate, methoxypolyethylene glycol (meth) acrylate, methoxydipropylene glycol (meth) acrylate, paracumylphenoxyethyl (meth) Acrylate, nonylphenoxypolyethylene glycol (meth) acrylate, tetrahydrofurfuryl (meth) acrylate, isobornyl (meth) acrylic (Meth) acrylic acid ester monomers such as cyclohexyl (meth) acrylate, benzyl methacrylate, N, N-dimethyl (meth) acrylamide, N, N-dimethylaminopropyl (meth) acrylate, acryloylmorpholine , (Meth) acrylamide derivatives. Polyfunctional monomers include ethylene glycol di (meth) acrylate, diethylene glycol di (meth) acrylate, triethylene glycol di (meth) acrylate, polyethylene glycol di (meth) acrylate, tripropylene glycol di (meth) acrylate, polytetra Methylene glycol di (meth) acrylate, 1,4-butanediol di (meth) acrylate, 1,6-hexanediol di (meth) acrylate, 1,9-nonanediol di (meth) acrylate, 3-methyl-1, 5-pentanediol di (meth) acrylate, neopentyl glycol di (meth) acrylate, dimethylol-tricyclodecane di (meth) acrylate, hydroxypivalate neopentyl glycol di (meth) acrylate Bisphenol A polypropoxydiol di (meth) acrylate, trimethylolpropane tri (meth) acrylate, ethoxylated trimethylolpropane tri (meth) acrylate, propoxylated trimethylolpropane tri (meth) acrylate, pentaerythritol tri (meth) Acrylate, glyceryl tri (meth) acrylate, propoxylated glyceryl tri (meth) acrylate, tris (2-hydroxyethyl) isocyanurate triacrylate, pentaerythritol tetra (meth) acrylate, ditrimethylolpropane tetra (meth) acrylate And dipentaerythritol penta (meth) acrylate, dipentaerythritol hexa (meth) acrylate, and the like.

  Examples of the photopolymerization initiator (S2) include 1-hydroxycyclohexyl phenyl ketone, 2-hydroxy-2-methyl-1-phenylpropan-1-one, 2,2-dimethoxy-1,2-diphenylethane-1 -One, 2,4,6-trimethylbenzoyldiphenylphosphine oxide, bis (2,4,6-trimethylbenzoyl) -phenylphosphine oxide, and the like. Among these, the irradiation device for curing the photocurable resin composition and the curability of the photocurable resin composition can be arbitrarily selected.

  The amount of the photopolymerization initiator (S2) contained in the photocurable resin composition is based on the total amount of the photocurable resin composition from the viewpoint of curability and cost of the photocurable resin composition (100% by mass). ) Is preferably 0.5% by mass or more and 10.0% by mass or less.

  These photocurable prepolymer (P2), reactive diluent monomer (M2) and photopolymerization initiator (S2) can be used alone or in combination of two or more.

  Specifically, a photopolymerizable component composed of urethane acrylate, epoxy acrylate, tripropylene glycol diacrylate and methoxytriethylene glycol acrylate (specifically, photocurable prepolymer (P2) and reactive dilution monomer (M2)). In consideration of the refractive index, the viscosity, the influence on the performance of the optical function layer 12, etc., they are arbitrarily mixed and used.

  Moreover, you may add a silicone, an antifoamer, a leveling agent, a solvent, etc. to a light absorption part structure composition as an additive as needed.

  As the light-absorbing particles 16, 16,..., Light-absorbing colored particles such as carbon black are preferably used. However, the present invention is not limited to these, and a specific wavelength is selectively selected according to the characteristics of the image light. Absorbing colored particles may be used. Specific examples include organic fine particles colored with metal salts such as carbon black, graphite, and black iron oxide, dyes, pigments, colored glass beads, and the like. In particular, colored organic fine particles are preferably used from the viewpoints of cost, quality, availability, and the like. More specifically, acrylic cross-linked fine particles containing carbon black, urethane cross-linked fine particles containing carbon black, and the like are preferably used. Such colored particles are usually contained in the light absorbing part constituting composition in a range of 3% by mass to 30% by mass. The average particle diameter of the colored particles is preferably 1.0 μm or more and 20 μm or less. When forming the light absorbing portions 14, 14,..., The doctor blade is used after filling the light absorbing portions constituting composition containing the colored particles into the recesses 13a, 13a,. And a step of scraping off the excess light absorbing portion constituting composition. At this time, by using colored particles having an average particle diameter of 1.0 μm or more, it becomes difficult for the colored particles to pass through the gap between the doctor blade and the upper portions of the light transmitting portions 13, 13,. It is possible to prevent the colored particles from remaining on the top of 13,.

  As described above, the optical sheet 10 can be obtained by forming the light transmitting portions 13, 13,... And the light absorbing portions 14, 14,.

  The optical sheet 10 may be further laminated with layers having other functions as necessary. Specifically, for example, an electromagnetic wave shielding layer, a wavelength filter layer, an antiglare layer, an antireflection layer, a hard coat layer, and the like can be formed by bonding using an adhesive layer. The order of lamination of these layers and the number of laminations are appropriately determined according to the use of the optical sheet.

  The electromagnetic wave shielding layer is a layer having a function of blocking electromagnetic waves. As long as the layer has the function, a means for blocking electromagnetic waves is not particularly limited. Examples thereof include those formed by, for example, an etching method, a printing method, a vapor deposition method, and a sputtering method, and are appropriately designed according to electromagnetic waves to be blocked.

  The wavelength filter layer is a layer having a function of filtering light having a predetermined wavelength. The wavelength to be filtered can be appropriately selected according to need. Examples include a layer that cuts neon rays emitted from a plasma display panel (PDP) or cuts infrared rays, near infrared rays, and ultraviolet rays. Can do.

  The antiglare layer is a layer having a function of suppressing so-called glare and is sometimes called an antiglare layer or an AG layer. A commercially available layer can be used as such an antiglare layer.

  The antireflection layer is a layer that is disposed closest to the viewer and has a function of preventing reflection of external light. According to this, it can suppress that external light reflects on the observer side surface of an optical sheet, returns to the observer side, and what is called reflection arises and it becomes difficult to see an image | video. Such an antireflection layer can be constituted by using a commercially available antireflection film.

  The hard coat layer may be referred to as an HC layer. This is a layer in which a film having a function capable of imparting scratch resistance is provided in order to prevent the image display surface from being scratched.

  The adhesive layer is a layer in which an adhesive is disposed. An acrylic adhesive can be mentioned as this adhesive. However, the pressure-sensitive adhesive is not limited to this as long as necessary light transmittance, adhesiveness, and weather resistance can be obtained. Depending on the layer structure, it is desirable to include a UV absorber (benzotriazole type or the like) having an effect of absorbing ultraviolet rays in the pressure-sensitive adhesive in order to prevent deterioration of the pigment. In addition, the adhesive layer may include a UV absorber, a near infrared absorber, a Ne-cut absorber (which absorbs neon rays), a toning pigment, and the like in the pressure-sensitive adhesive.

  Hereinafter, the present invention will be described in more detail with reference to examples. However, the present invention is not limited to the examples.

<Example 1>
In Example 1, a die roll was manufactured by forming grooves in a base having a hard copper plating (Vickers hardness 210 Hv) having a diameter of 400 mm and a width of 1000 mm and a thickness of 0.5 mm on the surface. The groove to be cut has a pitch of 51 μm, the cut depth in the groove portion is 79 μm, and the cut depth in the outer peripheral surface of the annular protrusion is 10 μm. The substrate was cut at a rotation speed of 400 rpm and a cutting speed of 4 μm / rotation.
In Example 1, a diamond tip was used, the apex angle was 6 degrees, the lateral clearance angle was 3 degrees, the front clearance angle was 6 degrees, and the bite tip width was 41 μm.
As a result, it was possible to cut with one diamond tip from the cutting start point to the end point, and the groove shape could be kept within the tolerance.

<Example 2>
In Example 2, the pitch of the groove to be cut was 58 μm, and the depth of cut at the groove was 115 μm. The apex angle of the diamond tip was 1 degree, the lateral clearance angle was 2.5 degrees, the front clearance angle was 15 degrees, and the cutting tool tip width was 46 μm. All other conditions are the same as in Example 1.
As a result, even in Example 2, the cutting start point to the end point could be cut with one diamond tip, and the groove shape could be kept within the tolerance.

<Example 3>
In Example 3, the pitch of the groove to be cut was 45 μm, and the depth of cut at the groove was 80 μm. The apex angle of the diamond tip was 3.8 degrees, the lateral clearance angle was 2.5 degrees, the front clearance angle was 15 degrees, and the cutting tool tip width was 36 μm.
Cutting was performed at a cutting speed of 2 μm / rotation. All other conditions are the same as in Example 1.
As a result, even in Example 3, the cutting start point to the end point could be cut with one diamond tip, and the groove shape could be kept within the tolerance.

<Example 4>
In Example 4, the cutting speed was changed from 1.5 μm / revolution to 5.5 μm / revolution. All other conditions were the same as in Example 1. That is, the diamond tip had an apex angle of 6 degrees, a lateral clearance angle of 3 degrees, a front clearance angle of 6 degrees, and a bite tip width of 41 μm. The results are shown in Table 1. Here, the “cutting start part” means the shape of the annular protrusion in the part where the cutting is started, and the “cutting end part” means the shape of the annular protrusion in the part where the cutting is completed. In Table 1, “◎” indicates that the shape of the annular protrusion is good, “◯” indicates that the annular protrusion has a slight tilt but is in a good range, and “△” indicates that the annular protrusion is more circular than “◯”. This is a case where the protrusion shape is largely collapsed but within an allowable range.

  As can be seen from Table 1, when the cutting speed is 2.0 (μm / rotation) or more and 5.0 (μm / rotation) or less, a more favorable annular protrusion shape is formed from the cutting start part to the cutting end part. I can.

<Comparative Example 1>
In Comparative Example 1, the lateral clearance angle of the diamond tip was set to 1 degree under the conditions of Example 1, and all other conditions were the same as in Example 1.
As a result, although cut with a single diamond tip, a streak-like pattern appears in the appearance from around 700 mm out of a substrate with a width of 1000 mm, and the ring-shaped protrusion collapses and a good groove and ring-shaped protrusion cannot be obtained. It was.

10 Optical sheet 11 Base material layer (base material)
DESCRIPTION OF SYMBOLS 12 Optical function layer 13 Light transmission part 14 Light absorption part 15 Binder part 16 Light absorption particle 20 Mold roll 21 Roll base | substrate 22 Annular protrusion 30 Cutting tip (cutting tool)

Claims (8)

A method of manufacturing a mold roll for molding the uneven portion of the optical sheet having an uneven shape,
Rotating a roll base having a layer to be processed formed on the surface, and forming a groove corresponding to the unevenness of the optical sheet with a cutting tool;
A method for producing a mold roll, wherein a side clearance angle of the cutting tool is 2 degrees or more and 5 degrees or less.   The method for producing a mold roll according to claim 1, wherein the roll base has a diameter of 300 mm or more and 500 mm or less, and the groove is formed at a rotation speed of the roll base of 300 rpm or more and 600 rpm or less.   The method for manufacturing a mold roll according to claim 1 or 2, wherein a cutting direction of the cutting tool is a direction orthogonal to an axial direction of the roll base rotating shaft.   The die roll manufacturing method according to any one of claims 1 to 3, wherein a cutting speed of the cutting tool is 2 µm / rotation or more and 5 µm / rotation or less.   The die roll according to any one of claims 1 to 4, wherein the cutting tool is retracted after the roll base is rotated once or more in a posture in which the cutting tool has reached the cutting depth. Manufacturing method.   The cutting tool is fed at a pitch that is half the pitch of the concave portion so as to alternately cut the bottom of the concave portion of the concave and convex portions to be formed on the roll base and the outer peripheral portion of the convex portion. The manufacturing method of the metal mold | die roll as described in any one of claim | item 1 -5.   The die roll manufactured by the manufacturing method of the die roll as described in any one of Claims 1-6.   A step of filling a photocurable material between the mold roll according to claim 7 and a base material, and irradiating the photocurable material with light in the filled state to form the photocurable material. The manufacturing method of the optical sheet including the process of hardening material.

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