JP2000238052A - Manufacture of lens sheet - Google Patents

Abstract

PROBLEM TO BE SOLVED: To easily manufacture a high quality both-surface lens sheet, the direction of lens train formed on both surfaces of which are different from each other and each lens of which has no defects. SOLUTION: In a manufacturing method, in which an activation energy ray curing composition is poured between a first cylindrical lens mold and a transparent base material so as to produce a first lens part 1 by irradiating the first lens part 1 by irradiating activation energy rays and a second lens part 2 is produced on the other surface of the transparent base material, a cylindrical lens mold, in which a thin plate-like lens mold 6 having a lens pattern as at least one cylindrical lens molded thereon is wound around a core roll 9, is used.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a notebook computer,
The present invention relates to a method for manufacturing a lens sheet such as a prism sheet used for a liquid crystal display device used for a liquid crystal television or the like, various signboards, a sign device, and the like, and more specifically to a double-sided lens sheet having a lens pattern formed on both surfaces. The present invention relates to a method for manufacturing a lens sheet capable of manufacturing an excellent lens sheet having no lens defects such as a defective lens shape with high productivity.

[0002]

2. Description of the Related Art In recent years, color liquid crystal display devices have been widely used in various fields such as portable notebook personal computers, portable liquid crystal televisions and video integrated liquid crystal televisions. This liquid crystal display device basically includes a backlight unit and a liquid crystal display element unit. As the backlight unit, there are a direct type in which a light source is provided directly below a liquid crystal display element and an edge light type in which a light source is provided on a side surface of a light guide. I have. The edge light system is a backlight of a system in which a light source is arranged on a side surface of a plate-shaped light guide to emit light on the entire surface of the light guide.

In such a liquid crystal display device, it is required to extend the battery driving time. However, the power consumption of the backlight used in the liquid crystal display device is large, and the battery driving time is extended. Is an obstacle for Keeping the power consumption of this backlight as low as possible will extend the battery operating time,
This is an important issue in increasing the practical value of the above products. However, if the brightness of the backlight is reduced by suppressing the power consumption of the backlight, the liquid crystal display becomes difficult to see, which is not preferable. Therefore, in order to suppress power consumption without sacrificing the luminance of the backlight, it is desired to improve the optical efficiency of the backlight. As means for realizing this, Japanese Utility Model Application Laid-Open No. 3-69184
As disclosed in Japanese Unexamined Patent Publication (Kokai) No. H10-209, a lens sheet having a large number of lens rows such as a prism row and a lenticular row formed on one side is provided with a light guide such that the lens row forming surface is opposite to the light guide. A backlight mounted on a light exit surface via a diffusion sheet has been put to practical use.

However, in such a backlight in which a lens sheet is placed on the light exit surface side of the light guide such that the lens row forming surface is opposite to the light guide, the refraction of the lens sheet is mainly used. Since the direction control of the light emitted from the light guide in the normal direction is performed, the direction control of the emitted light is mainly performed in a direction orthogonal to the direction in which the lens rows of the lens sheet extend, so that optical efficiency is improved. There is a limit to the improvement of the brightness, and there is a problem that the luminance in the normal direction can be improved only to a certain extent.

On the other hand, for the purpose of improving the luminance in the normal direction, a backlight in which two lens sheets are mounted on each other so that the lens rows are orthogonal to each other has been widely used. However, in such a backlight, the number of members constituting the backlight is increased, so that the assembling work is complicated, and the light emitted from the light guide is mainly directed to the normal direction by utilizing the refraction of the lens sheet. Therefore, some light is reflected and refracted laterally, and the luminance in the normal direction can be improved only to a certain extent.

Therefore, as a method of reducing the number of components of the backlight and further improving the optical efficiency of the backlight, Japanese Patent Publication No. 7-27136 and Japanese Patent Publication No. 7-27
As proposed in Japanese Patent Publication No. 137, a lens unit or a rough surface is formed on the surface of the light guide to emit light with high directivity, and the light is output so that the prism row forming surface is on the light guide side. By the prism sheet arranged on the exit surface of the light guide,
Methods for performing direction control in the normal direction have been studied.
In such a backlight, since the direction control of the light emitted from the light guide is performed mainly by utilizing the total reflection effect of the prism sheet, a backlight having high optical efficiency and extremely high luminance can be obtained. Things. In such a backlight, since the emitted light with high directivity from the prism sheet is emitted, the luminance in the normal direction becomes extremely high. (A direction perpendicular to the plane and the plane of emission)).

Further, as proposed in Japanese Patent Application Laid-Open Nos. 7-191319 and 7-198913, the apex angle of the incident surface located on the light guide side is 60 ° to 70 °.
A large number of prism rows of about 90 ° to 100 ° are formed in parallel, and the apex angle is 90 ° to 10 ° on the opposite exit surface.
There has been proposed a method of mounting a double-sided prism sheet formed by arranging a large number of prism rows of about 0 ° in parallel on a light guide to reduce the power consumption and the brightness of a backlight.

[0008]

However, in the production of such a double-sided prism sheet, a production apparatus such as a general injection molding method or a thermal transfer method requires a large-scale production apparatus, a long production cycle, and mass production. However, it has problems that the production cost is high. Further, as disclosed in Japanese Patent Application Laid-Open No. 1-192529, an ultraviolet-curable resin liquid is injected into a flat lens mold, and a transparent base material is superposed thereon. There is a method of manufacturing a lens sheet by curing a resin liquid and transferring a lens-type lens pattern. However, in the case of a double-sided prism sheet, this method cannot sufficiently solve the problems of mass production and manufacturing cost, and it is easy to damage one prism surface formed earlier when performing the second molding. It also has problems.

Therefore, as a method for manufacturing a double-sided lenticular lens sheet or the like, as described in JP-A-3-64701, two lenticular lenses are used and both lenticular lenses are made of an ultraviolet-curable resin. A method of sequentially forming has been proposed. However, there is no problem when both lens rows are formed in parallel as in a normal double-sided lenticular lens sheet described in JP-A-3-64701, but a lens formed on both sides such as a double-sided prism sheet. If the directions of the rows are different, the lens pattern is formed on at least one of the roll-shaped lens molds so that the lens rows extend in a direction inclined by a predetermined angle from a direction horizontal or perpendicular to the center axis of the roll-shaped lens mold. Need to be formed. Thus, a very fine lens pattern is formed on the roll-shaped lens mold with high precision so that the lens array extends in a direction inclined by a predetermined angle from the horizontal or vertical direction with respect to the center axis of the roll-shaped lens mold. It is very difficult to perform such a process, and there is a problem that a lens defect such as a defective lens shape is likely to occur, and the productivity of the lens mold is poor.

Accordingly, an object of the present invention is to produce an excellent lens sheet free of lens defects such as a defective lens shape with high productivity in the production of a double-sided lens sheet in which the directions of lens rows formed on both sides are different. It is to provide a method.

[0011]

In order to solve the above-mentioned problems, the present inventors have studied the manufacturing process of a double-sided lens sheet, and formed a lens pattern as at least one cylindrical lens type. By using a wound cylindrical lens mold in which the thin plate lens mold is wound around a core roll, the lens is inclined at a predetermined angle from a horizontal or vertical direction with respect to the center axis of the cylindrical lens mold. The present inventors have found that a very fine lens pattern having extended rows can be imparted to a cylindrical lens mold with high precision and high productivity, and arrived at the present invention.

That is, according to the method for manufacturing a lens sheet of the present invention, the first lens array in which a large number of linearly extending lens rows are connected is provided.
Injecting an active energy ray-curable composition between the lens pattern forming surface of the first cylindrical lens type having the lens pattern formed thereon and the transparent substrate, irradiating the active energy ray through the transparent substrate A step of curing the active energy ray-curable composition to form a first lens on one surface of a transparent substrate, and forming a second lens pattern formed by connecting a large number of linearly extending lens arrays. Injecting an active energy ray-curable composition between the lens pattern forming surface of the cylindrical lens type and the transparent substrate, and irradiating the active energy ray through the transparent substrate to cure the active energy ray-curable composition Forming a second lens on the other surface of the transparent base material, wherein the first lens pattern and the second lens pattern each extend in a lens row. Are formed so as to be in different directions with respect to the central axis of each cylindrical lens type, and the lens pattern is defined as at least one of the first cylindrical lens type and the second cylindrical lens type. The present invention is characterized in that a wound cylindrical lens mold obtained by winding the formed thin plate lens mold around a core roll is used.

According to the present invention, a thin plate lens mold on which a predetermined lens pattern is formed in advance is punched out so that the lens array extends in a direction inclined by a predetermined angle, and is wound around a core roll. By using a wound cylindrical lens mold, a lens pattern in which a lens array extends in a direction inclined by a predetermined angle from a horizontal or vertical direction with respect to the center axis of the cylindrical lens mold can be precisely formed into a cylindrical lens mold. A high-quality double-sided lens sheet that can be formed with high productivity and has no lens defects can be easily manufactured.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS First, a double-sided lens sheet manufactured by the manufacturing method of the present invention will be described with reference to FIG. FIG. 1 shows a double-sided prism sheet on which a lens portion in which a large number of prism rows 1 and 2 extending linearly are continuously provided is formed. 2 are arranged in parallel, and the angle (prism crossing angle) between the ridge directions of the prism rows 1 and 2 is a predetermined angle.

The prism crossing angle between the prism row 1 and the prism row 2 is not particularly limited and can be appropriately determined according to the purpose, but is preferably formed so as to be at least 5 ° or more. , More preferably 5
~ 90 °, more preferably 10-60 °
Range. This is because when the prism crossing angle is less than 5 °, the luminance of the backlight tends to be greatly reduced. Further, by setting the prism crossing angle to 60 ° or less, a sufficient viewing range in the vertical direction can be secured. When such a double-sided prism sheet is used for a backlight of a liquid crystal display device, by forming a prism array on both sides at a specific prism crossing angle, the vertical direction (the surface orthogonal to the entrance surface and the exit surface of the light guide) is formed. Direction), the directional light emitted from the light guide is deflected in the normal direction by the prism row 1 on the light guide side, and the distribution of light in the vertical direction is widened by the prism row 2 on the opposite side, while the horizontal direction. (In the direction parallel to the light-incident surface of the light guide and perpendicular to the light-exiting surface), it is possible to condense the light dispersed in the normal direction, thereby improving the luminance and expanding the vertical visual field range. Can be.

The optimum range of the prism crossing angle differs depending on the apex angle of the prism row 2. The smaller the prism crossing angle as the apex angle of the prism row 2 becomes larger, the balance between the improvement of the luminance and the expansion of the visual field range. It is preferable from the viewpoint of properties. Further, from the viewpoint of the quality and productivity of the prism sheet, particularly, the cutting accuracy of the prism type and the occurrence of cutting defects such as burrs, those having a large apex angle of the prism array 2 are preferable. For example, when the apex angle of the prism array 2 is 130 ° to 140 °, the prism crossing angle is preferably in a range of about 5 ° to 40 °.

The apex angles, pitches, etc. of the prism rows 1 and 2 of the double-sided prism sheet are not particularly limited.
The vertex angle of the prism array 1 formed on one surface is 50 ° to 75 °.
And the apex angle of the prism array 2 formed on the other surface is preferably in the range of 110 ° to 150 °. The pitch of the prism rows is preferably about 30 μm to 0.5 mm, and the thickness is preferably about 0.1 to 3 mm.

The method for producing a lens sheet according to the present invention will be described with reference to FIGS. 2 and 4 show a cylindrical lens mold used in the present invention, and FIG. 3 shows a thin plate lens mold used for a wound cylindrical lens mold. FIG. 5 is a schematic view illustrating a manufacturing process of the lens sheet of the present invention.

In FIG. 5, reference numerals 4 and 8 denote first cylindrical lens molds on which a first lens pattern and a second lens pattern, each of which has a plurality of lens arrays such as a prism array extending linearly, are connected. And a second cylindrical lens type, such as aluminum, brass, metal molds such as steel,
Silicon resin, polyurethane resin, epoxy resin, AB
A resin mold made of a synthetic resin such as an S resin, a fluorine resin, or a polymethylpentene resin, an electroforming mold manufactured by a Ni electroforming method, or the like is used. In particular, it is desirable to use a metal mold from the viewpoint of heat resistance and strength. As a lens type of at least one of the first cylindrical lens type 4 and the second cylindrical lens type 8, as shown in FIGS. 3 and 4, a thin plate lens type 6 on which a lens pattern is formed is a predetermined type. A wrapped cylindrical lens mold is used in which the lens array is cut out so that the lens array extends in a direction inclined by the angle α, and this is wrapped around the core roll 9 and fixed. When winding and fixing the thin plate-shaped lens mold 6 around the core roll 9, it is necessary to fix the lens pattern accurately so that the lens array of the lens pattern extends in a predetermined direction. It is preferable to apply plating such as copper or nickel to the surface of such a wound cylindrical lens mold in order to prevent various types of corrosion. In this way, the thin plate lens mold 6 is
A very fine lens in which a lens array extends in a direction inclined by a predetermined angle from a horizontal or vertical direction with respect to the center axis of the cylindrical lens mold by using a wound cylindrical lens mold wound around The pattern can be formed on the cylindrical lens mold with high precision and high productivity.

In the present invention, the above-mentioned wound cylindrical lens type is used as at least one lens type, and the same winding type using a thin plate type lens type 6 is used as the other cylindrical lens type. A cylindrical lens mold may be used, or a lens in which a lens pattern is directly formed on a cylindrical lens mold as shown in FIG. 2 may be used. In the case where the direction in which the lens rows of the lens pattern extend at a predetermined angle with respect to the central axis of the cylindrical lens mold is used, it is preferable to use the former wound cylindrical lens mold. In this case, the direction in which the lens rows extend when the die is removed from the thin plate lens mold 6 is set so that the obtained crossing angle of the double-sided lens sheet becomes a desired angle. on the other hand,
In the case where the lens array of the lens pattern is used so as to extend in the horizontal or vertical direction with respect to the central axis of the cylindrical lens mold, it is possible to use a lens in which the lens pattern is directly formed on the latter cylindrical lens mold. It is preferable to use such as the other cylindrical lens type. In this case, in order to make the cutting material particles uniform and fine, it is also possible to form a thick plating of copper or nickel on the core roll and form a lens pattern on the plating layer portion.

The manufacturing process of the lens sheet of the present invention using such a cylindrical lens mold will be described with reference to FIG. The manufacturing process includes a first lens forming unit 17 that forms a first lens unit using a first cylindrical lens mold, and a second lens forming unit that forms a second lens unit using a second cylindrical lens mold. It is divided into a lens forming section 18.

A transparent substrate 11 is supplied to the first cylindrical lens mold 4 along the lens pattern forming surface, and the first cylindrical lens mold 4 is provided between the first cylindrical lens mold 4 and the transparent substrate 11.
Active energy ray-curable composition 12 in resin tank 14
From the supply nozzle 15. Transparent substrate 1
A nip roll 10 for making the thickness of the supplied first active energy ray-curable composition 12 uniform is provided outside 1. As the nip roll 10, a metal roll, a rubber roll, or the like is used. Also, the first
In order to make the thickness of the active energy ray-curable composition 12 uniform, it is preferable that the nip roll 10 is processed with high accuracy in terms of roundness, surface roughness, and the like. Those having a high hardness of 60 degrees or more are preferable. The nip roll 10 needs to accurately adjust the thickness of the active energy ray-curable composition 12, and is operated by a pressure adjusting mechanism 13. As the pressure adjusting mechanism 13, a hydraulic cylinder, a pneumatic cylinder, various screw mechanisms and the like can be used, but a pneumatic cylinder is preferable from the viewpoint of simplicity of the mechanism. The air pressure is controlled by a pressure regulating valve or the like.

First active energy ray-curable composition 12
Is supplied between the first cylindrical lens mold 4 and the transparent substrate 11, and then the first active energy ray-curable composition 12
The active energy ray is irradiated from the active energy ray irradiation device 16 through the transparent substrate 11 in a state sandwiched between the cylindrical lens mold 4 and the transparent substrate 11 to form the first active energy ray-curable composition. The lens pattern formed on the first cylindrical lens mold 4 is polymerized and cured to transfer the lens pattern formed on the first cylindrical lens mold 4, and a first lens portion is formed on one surface of the transparent substrate 11. As the active energy ray irradiation device 16, a chemical lamp for chemical reaction, a low-pressure mercury lamp, a high-pressure mercury lamp, a metal halide lamp, a visible light halogen lamp, or the like is used. The irradiation amount of the active energy ray is 200 to 60.
The integrated energy at a wavelength of 0 nm is 0.1 to 50 J / cm
It is preferably set to an extent of ² . The active energy ray irradiation atmosphere may be air or an inert gas atmosphere such as nitrogen or argon.

Next, the transparent substrate 11 having a lenticular lens formed on one surface is placed in the second lens forming portion 18.
And supplied so that the other surface thereof comes into contact with the lens pattern forming surface of the second cylindrical lens mold 8.
The second cylindrical lens mold 8 may be installed adjacent to the first cylindrical lens mold 4, or may be installed at a fixed interval. In the case of installation at regular intervals, the first cylindrical lens mold 4 and the second cylindrical lens mold 8
Is required to be larger than the thickness of the first lens pattern formed on the transparent substrate 11,
Usually, it is preferable to provide an interval of about 1 mm or more.
The second cylindrical lens mold 8 may be installed so as to be movable in the cylindrical axis direction. The second active energy ray-curable composition 12 ′ is continuously supplied from the resin tank 14 ′ to the supply nozzle 15 ′ between the second cylindrical lens mold 8 and the transparent substrate 11. On the outside of the transparent substrate 11, a nip roll 10 'operated by a pressure adjusting mechanism 13' for uniforming the thickness of the supplied second active energy ray-curable composition 12 'is provided. . After supplying the second active energy ray-curable composition 12 ′ between the second cylindrical lens mold 8 and the transparent substrate 11, the second active energy ray-curable composition 12 ′ is formed into the second cylindrical form. Shape lens type 8
The active energy ray is irradiated from the active energy ray irradiation device 16 ′ through the transparent substrate 7 while being sandwiched between the transparent substrate 11 and the second active energy ray-curable composition 12 ′. Then, the lens pattern formed on the second cylindrical lens mold 8 is transferred to form a second lens pattern on one surface of the transparent substrate 11.

The active energy ray-curable compositions 12, 1 supplied between the cylindrical lens molds 4, 8 and the transparent substrate 11
2 ′ is preferably maintained at a constant viscosity in order to make the thickness of the relaxation layer formed between the first and second lens portions and the transparent substrate 11 and the lens portion uniform. The viscosity range varies depending on the thickness of the lens portion and the relaxation layer to be formed, but is generally preferably in the range of 20 to 3000 mPa · S, more preferably 100 to 1 mPa · S.
000 mPa · S. When the viscosity of the active energy ray-curable compositions 12, 12 ′ is less than 20 mPa · S, it is necessary to set the nip pressure extremely low or to extremely increase the molding speed for forming the relaxation layer. Become. However, when the nip pressure is extremely low, the pressure adjusting mechanisms 13, 13 'tend to be unable to operate stably,
It tends to cause unevenness in the thickness of the lens portion and the relaxation layer. If the molding speed is extremely high, the irradiation amount of the active energy ray is insufficient, and the active energy ray-curable composition 1
The curing of 2, 12 'tends to be insufficient. On the other hand, the active energy ray-curable compositions 12, 12 ′ have a viscosity of 30.
If it exceeds 00 mPa · S, the active energy ray-curable compositions 12 and 12 ′ do not sufficiently spread to the details of the lens patterns of the cylindrical lens molds 4 and 8, making it difficult to accurately transfer the lens shape, Defects tend to occur due to the mixing of water, and productivity tends to deteriorate due to an extremely low molding speed. In order to maintain the viscosity of the active energy ray-curable compositions 12, 12 'constant as described above, the active energy ray-curable compositions 12, 12' are required.
It is preferable to install heat source equipment such as a sheath heater and a hot water jacket outside or inside the resin tanks 14 and 14 'so that the temperature control can be performed.

Further, the transparent substrate 11 used in the present invention
The material is not particularly limited as long as it is a material that transmits active energy rays such as ultraviolet rays and electron beams.A flexible glass plate or the like can be used, but polyester resin, acrylic resin, polycarbonate resin, vinyl chloride, etc. A transparent resin sheet or film such as a base resin or a polymethacrylimide resin is preferred. In particular, those made of polymethyl methacrylate having a low surface reflectance, a mixture of polymethyl acrylate and polyvinylidene fluoride-based resin, polycarbonate-based resin, and polyester-based resin such as polyethylene terephthalate are preferable. Although the thickness of the transparent substrate 2 varies depending on the application, a thickness in the range of about 50 μm to 5 mm is used. In addition, the transparent base material 11 has a surface which has been subjected to an adhesion improving treatment such as an anchor coating treatment in order to improve the adhesion between the lens array made of the active energy ray-curable resin and the transparent base material 11. preferable.

The active energy ray-curable resin forming the lens arrays 1 and 2 is not particularly limited as long as it is cured with active energy rays such as ultraviolet rays and electron beams. Epoxy resins, (meth) acrylate resins such as polyester (meth) acrylate, epoxy (meth) acrylate, and urethane (meth) acrylate are exemplified. Among them, (meth) acrylate resins are particularly preferable from the viewpoint of their optical characteristics and the like. As the active energy ray-curable composition used for such a cured resin, polyhydric acrylate and / or polyhydric methacrylate (hereinafter, referred to as polyhydric (meth) acrylate) in terms of handleability, curability, and the like. , Monoacrylate and / or monomethacrylate (hereinafter, referred to as mono (meth) acrylate), and a photopolymerization initiator using active energy rays as a main component are preferable. Representative polyvalent (meth) acrylates include polyol poly (meth) acrylate, polyester poly (meth) acrylate, epoxy poly (meth) acrylate, urethane poly (meth) acrylate, and the like. These are used alone or as a mixture of two or more. Also, as the mono (meth) acrylate,
Mono (meth) acrylates of monoalcohols and mono (meth) acrylates of polyols may be mentioned. In the latter case, it is thought that the influence is caused by free hydroxyl groups. When using a metal mold, it is better not to use a large amount of the metal mold. Also,
Since (meth) acrylic acid and its metal salt also have high polarity, it is better not to use a large amount when using a metal type. In the present invention, in the active energy ray-curable composition, if necessary, an antioxidant, a yellowing inhibitor, an ultraviolet absorber, a bluing agent, a pigment, an anti-settling agent, an antifoaming agent, Various additives such as an inhibitor, an anti-fogging agent, a thermal polymerization initiator, a sensitizer, a reducing agent, and a diffusing material may be blended.

When the active energy ray-curable composition is put into a resin tank, the active energy ray-curable composition is filtered through a filter or the like in order to avoid contamination of the resulting lens sheet with foreign substances. It is preferable to throw in the waste after removing it. Further, in order to suppress the occurrence of lens defects due to bubbles generated when charged into the resin tank, it is preferable to remove bubbles by vacuum defoaming or the like before supplying to the line.

[0029]

The present invention will be described below in more detail with reference to examples. As shown in FIG. 6, a diameter of 220 mm and a length of 450
Vickers hardness of 2 mm on the circumference of an iron core roll 19 mm.
00 hard copper plating 20 was applied in a thickness of 100 μm. A pitch of 50 μm is applied to the hard copper plating 20 so that the ridge direction of the prism row is orthogonal to the center axis of the core roll 19.
m, prism array 21 having a vertical angle of 65 ° and an isosceles triangular cross section
Was stamped to prepare a first cylindrical lens mold 22. On the other hand, as shown in FIG.
mm JIS brass three kinds of thin plate, pitch 50μ
m, a prism array having an apex angle of 130 ° and an isosceles triangular cross section was stamped to prepare a thin plate lens mold 24. Electroless nickel plating having a thickness of 1 μm was applied to the thin plate lens mold 24 to prevent various types of corrosion. Then, the thin plate-shaped lens mold 24 was tilted by 15 ° with respect to the ridge direction of the prism row to 400 mm ×
The mold was cut into a rectangle having a size of 690 mm.
In order to fix the thin plate lens mold 24, the diameter is 220m.
A core roll 25 made of stainless steel having a length of 450 mm and a length of 450 mm is prepared, and a thin plate lens mold 24 is placed on the circumference of the core roll 25 so that the ridge line direction of the prism row with respect to the center axis of the core roll 25 is 7 mm.
It was wound at an angle of 5 ° and fixed with screws to prepare a second wound cylindrical lens mold 26.

As shown in FIG. 9, the first cylindrical lens mold 22 is set in the first lens forming section 38, and the second wound cylindrical lens mold 26 is set in the second lens forming section 39. .
Further, an NBR rubber roll 2 having a rubber hardness of 80 ° is provided close to the first and second cylindrical lens molds 22 and 26.
7, 27 'were arranged. The first cylindrical lens mold 22 is provided between the first cylindrical lens mold 22 and the first rubber roll 27.
A slightly larger polyethylene terephthalate film (PET film) 28 having a thickness of 188 μm is passed along the first cylindrical lens mold 22 and the first rubber roll is connected to the first rubber roll 27 by the first pneumatic cylinder 29. 27 and the first cylindrical lens mold 22
The film 28 was nipped. At this time, the operating pressure of the first pneumatic cylinder 29 was 0.1 MPa. As the first pneumatic cylinder 29, an SMC air cylinder having an air tube diameter of 32 mm was used. Further, a first ultraviolet irradiation device 30 was installed below the first cylindrical lens mold 22. The first UV irradiator 30 is 120 W / c
It has an ultraviolet intensity of 9.6 kW, a UV irradiation lamp manufactured by Western Quartz, a cold mirror type parallel light reflector, and a power supply. The first ultraviolet-curable composition 31 was previously mixed with a refractive index adjusting component, a catalyst, and the like, and then charged into a first resin tank 32. In the first resin tank 32, all parts in contact with the first ultraviolet curable composition 31 were SUS304. In order to control the liquid temperature of the first UV-curable composition 31 to 40 ° C. ± 1 ° C., a warm water jacket layer is provided, and hot water adjusted to 40 ° C. by the first temperature controller 33 is used. The UV curable composition 3 supplied to the warm water jacket layer and contained in the resin tank 32
The liquid temperature of 1 was kept constant. Further, bubbles generated at the time of charging were defoamed and removed by bringing the first resin tank 32 into a vacuum state by the first vacuum pump 34.

The first ultraviolet curable composition 31 was as follows, and the viscosity was adjusted to 300 mPa · S / 40 ° C. Phenoxyethyl acrylate 50 parts by weight (Biscoat # 192 manufactured by Osaka Organic Chemical Industry Co., Ltd.) Bisphenol A-diepoxy-acrylate 50 parts by weight (Epoxyester 3000A manufactured by Kyoeisha Yushi Kagaku Kogyo Co., Ltd.) 2-hydroxy-2-methyl-1-phenyl-propane -1-one (Darocur 1173 manufactured by Ciba-Geigy) 1.5 parts by weight Once the inside of the first resin tank 32 is returned to normal pressure and the tank is closed, 0.02 MPa is supplied into the first resin tank 32.
The first ultraviolet curable composition 31 is opened by applying air pressure and opening a valve below the first resin tank 32.
Through a first pipe 35 of which temperature is controlled, and a first rubber roll 2 from a first supply nozzle 36 of which temperature is also controlled.
7 was supplied between the PET film 28 and the first cylindrical lens mold 22 which were nipped between the first cylindrical lens mold 22. As the first supply nozzle 36, an AV101 valve manufactured by Iwashita Engineering Co., Ltd. equipped with a MN-18-G13 needle was used. Mitsubishi Electric 0.2
2.0 per minute with kW geared motor (reduction ratio 1/200)
While rotating the first cylindrical lens mold 22 at a speed of m, the first ultraviolet-curable composition 31 is sandwiched between the first cylindrical lens mold 22 and the PET film 28,
Ultraviolet light was irradiated from the first ultraviolet irradiation device 30 to polymerize and cure the first ultraviolet-curable composition 31 to form a first prism portion on one surface of the PET film 28.

Next, the PET film 28 having the first presumed portion formed on one surface is placed between the second wound cylindrical lens mold 26 and the second rubber roll 27 'on the other surface of the PET film 28. Are supplied along the second wrapped cylindrical lens mold 26 so that the second rubber roll 2
With a second pneumatic cylinder 29 'connected to 7'
The PET film 28 was nipped between the second rubber roll 27 ′ and the second wound cylindrical lens mold 26. At this time, the operating pressure of the second pneumatic cylinder 29 'is 0.1 MPa.
Met. The second ultraviolet-curable composition 31 ′ was previously mixed with a refractive index adjusting component, a catalyst, and the like, and then charged into a second resin tank 32 ′. Further, the foam generated at the time of charging is discharged to the second resin tank 3 by the second vacuum pump 34 '.
The inside of 2 ′ was evacuated and removed by applying a vacuum.

The second ultraviolet-curable composition 31 'was as follows, and the viscosity was adjusted to 150 mPa · S / 40 ° C. 70 parts by weight of phenoxyethyl acrylate (Biscoat # 192 manufactured by Osaka Organic Chemical Industry Co., Ltd.) 30 parts by weight of bisphenol A-diepoxy-acrylate (Epoxyester 3000A manufactured by Kyoeisha Yushi Kagaku Kogyo Co., Ltd.) 2-hydroxy-2-methyl-1-phenyl-propane -1-one (Darocur 1173 manufactured by Ciba-Geigy) 1.5 parts by weight Once the inside of the second resin tank 32 ′ is returned to normal pressure and the tank is closed, 0.02 M is filled in the second resin tank 32 ′.
By applying an air pressure of Pa and opening the valve at the bottom of the second resin tank 32 ', the second ultraviolet curable composition 31' is passed through a temperature-controlled second pipe 35 ', and the temperature is similarly controlled. Of the PET film 28 nipped between the second rubber roll 27 ′ and the second wound cylindrical lens mold 26 from the second supply nozzle 36 ′ and the second wound cylindrical lens mold 26. Supplied in between. The second wrapped cylindrical lens mold 26 at a speed of 2.0 m / min with a Mitsubishi Electric 0.2 kW geared motor 37 (reduction ratio 1/200)
While rotating the second ultraviolet curable composition 31 ′, the second wrapped cylindrical lens mold 26 and the PET film 28.
In the state of being sandwiched between the two, the second ultraviolet irradiation device 30 ′ irradiates ultraviolet rays to polymerize and cure the second ultraviolet curable composition 31 ′ to form the second prism portion on one surface of the PET film 28. Formed. Thereafter, the mold is released from the second wound cylindrical lens mold 26, and the intersection angle between the prism rows is 1
A 5 ° double-sided prism sheet was obtained. In the obtained double-sided prism sheet, the prism pattern formed in the lens shape was accurately transferred, and there was no lens defect such as a defective prism shape.

[0034]

According to the present invention, there is provided a double-sided lens sheet in which the directions of lens rows formed on both sides are different.
By using a wound cylindrical lens mold in which a thin plate lens mold in which a predetermined lens pattern is formed in advance so that the lens row extends in a direction inclined by a predetermined angle, and this is wound around a core roll A lens pattern in which a lens array extends in a direction inclined by a predetermined angle from a direction horizontal or vertical to a central axis of a cylindrical lens mold can be formed on a cylindrical lens mold with high precision and high productivity. A high-quality double-sided lens sheet free from defects can be easily manufactured.

[Brief description of the drawings]

FIG. 1 is a schematic perspective view of a double-sided prism sheet manufactured according to the present invention.

FIG. 2 is a schematic perspective view showing a cylindrical lens mold of the present invention.

FIG. 3 is a schematic view showing a thin plate lens type of the present invention.

FIG. 4 is a schematic perspective view showing a wound cylindrical lens mold of the present invention.

FIG. 5 is a schematic view showing a manufacturing process of the present invention.

FIG. 6 is a schematic perspective view showing a first cylindrical lens mold of the example.

FIG. 7 is a schematic view showing a thin plate lens type of an example.

FIG. 8 is a schematic perspective view showing a second wound cylindrical lens mold of the embodiment.

FIG. 9 is a schematic view showing a manufacturing process of the example.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 1st lens part 2 2nd lens part 3,11,28 Transparent base material 4,22 1st cylindrical lens type 5,21 1st lens pattern 6,24 Thin plate lens type 7,23 2 8, 26, second winding cylindrical lens mold 9, 19, 25 core roll 10, 10 ', 27, 27' nip roll 12, 12 ', 31, 31' active energy ray-curable composition 13, 13 ', 29, 29' Pressure adjustment mechanism 14, 14 ', 32, 32' Resin tank 15, 15 ', 36, 36' Supply nozzle 16, 16 ', 30, 30' Active energy ray irradiation device 17, 38th 1 lens forming section 18, 39 second lens forming section 20 copper plating 33, 33 'temperature controller 37 geared motor

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Claims (2)

[Claims] 1. An active energy ray hardening between a transparent substrate and a first cylindrical lens type lens pattern forming surface on which a first lens pattern in which a plurality of linearly extending lens rows are connected is formed. Injecting a transparent composition, irradiating an active energy ray through a transparent substrate to cure the active energy ray-curable composition and forming a first lens on one surface of the transparent substrate, and extending linearly A step of injecting an active energy ray-curable composition between a transparent lens and a second cylindrical lens-type lens pattern forming surface on which a second lens pattern in which a number of lens rows are connected is formed; A method for producing a lens sheet, comprising a step of irradiating an active energy ray through a base material to cure an active energy ray-curable composition and forming a second lens on the other surface of the transparent base material, lens The extending direction of each lens row of the pattern and the second lens pattern is formed so as to be different from the central axis of each cylindrical lens mold, and the first cylindrical lens mold and the second cylindrical mold are formed. A method of manufacturing a lens sheet, comprising using, as at least one of the lens molds, a cylindrical lens mold in which a sheet-like lens mold having a lens pattern formed thereon is wound around a core roll. 2. One of the first cylindrical lens type and the second cylindrical lens type has a lens array extending in a horizontal or vertical direction with respect to a center axis of the cylindrical lens type. 2. The method according to claim 1, wherein the lens pattern is formed directly on the cylindrical lens mold.