JP2009292060A - Lens sheet - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide the manufacturing method of a lens sheet, in which the contactness between light transmittable base material and an active energy beam curable composition can be improved under the condition that the generation of the warpage in the sheet is suppressed. <P>SOLUTION: In this manufacturing method of the lens sheet, in which the active energy beam curable composition 18 is arranged between the outer peripheral surface with the lens part transferring part thereon of a roll mold 14 and the light transmittable base material 12 so as to cure the active energy beam curable composition by irradiating the active energy beam curable composition with active energy beam through the light transmittable base material in order to make a lens part having a shape complementary with the lens part transferring pattern on the surface of the light transmittable base material out of active energy beam curable resin, the active energy beam curable composition is brought before its curing in the temperature range of ≥40°C and <80°C and at its curing in the range of ≥20°C and <40°C. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention generally relates to a method for manufacturing a lens sheet, and in particular, a lens for manufacturing a lens sheet, particularly a lens sheet such as a prism sheet, a lenticular lens sheet, and a Fresnel lens sheet, as a long lens sheet. The present invention relates to a sheet manufacturing method.

  Lens sheets such as prism sheets, lenticular lens sheets, and Fresnel lens sheets that are used as backlights for liquid crystal display devices, stereoscopic photographs, projection screens, condenser lenses for overhead projectors, and the like are known.

  As a method of manufacturing such a prism sheet, there is a method of continuously producing a long prism sheet by using a roll die having a micro-prism portion of the prism sheet and a complementary groove formed on the surface. Are known. In this manufacturing method, an active energy ray-curable composition is sandwiched between a roll mold and a long light-transmitting substrate, and the active energy ray-curable composition is activated with active energy rays from an active energy ray irradiation device. The prism sheet is manufactured by forming a microprism portion formed of the cured active energy ray-curable composition on the surface of the translucent substrate.

  A liquid crystal display device of a notebook computer in which such a prism sheet is used as a backlight is required to have high luminance and no luminance unevenness. However, if the lens sheet is warped, the sheet floats and the backlight A dark portion is formed on the liquid crystal display device, resulting in a liquid crystal display device having luminance spots.

  In order to prevent such warpage of the sheet, a method has been proposed in which the temperature of the active energy ray-curable composition at the time of curing is lowered and the thermal shrinkage is reduced. There was a problem that the adhesiveness with the active energy ray-curable composition was lowered.

  On the other hand, as a method for improving adhesion, a method has been proposed in which a transparent substrate is heated in advance to a temperature range of 25 degrees Celsius or more and less than 80 degrees Celsius to improve the surface activity of the transparent substrate (Patent Document 1). reference).

Japanese Patent Laid-Open No. 3-73319

  However, the method of Patent Document 1 has a problem that if the temperature of the resin of the transparent base material during curing is high, the amount of heat shrinkage increases and the warp of the lens sheet increases.

  The present invention has been made to solve such a problem, and improves the adhesion between the translucent substrate and the active energy ray-curable composition while suppressing the occurrence of warpage of the sheet. An object of the present invention is to provide a method for manufacturing a lens sheet.

According to the present invention,
An active energy ray-curable composition is disposed between an outer peripheral surface of a roll mold having a lens part transfer pattern formed on the outer peripheral surface and a translucent substrate, and the active energy ray curing is performed through the translucent substrate. The active energy ray curable composition is irradiated with active energy rays to cure the active energy ray-curable composition, and the lens portion having a shape complementary to the lens portion transfer pattern is cured on the surface of the translucent substrate. A lens sheet manufacturing method formed of resin,
The active energy ray-curable composition is in a temperature range of 40 degrees Celsius or more and less than 80 degrees Celsius before the curing, and at the time of curing, the active energy ray curable composition is in a range of 20 degrees Celsius or more and less than 40 degrees Celsius.
A lens sheet manufacturing method is provided.

According to such a configuration,
The adhesion between the translucent substrate and the active energy ray-curable composition can be improved while suppressing the occurrence of warpage of the sheet.

  According to the other preferable aspect of this invention, the said active energy ray-curable composition is supplied by apply | coating to one side of the said translucent base material, and supply of the said active energy ray-curable composition The temperature of the hour is in the range of 40 degrees Celsius or more and less than 80 degrees Celsius.

According to another preferred embodiment of the present invention, the active energy ray-curable composition is adjusted to a temperature of the outer peripheral surface of the roll mold so that the temperature is 20 degrees Celsius or more and less than 40 degrees Celsius during the curing. Controlled to range.
According to the other preferable aspect of this invention, the temperature of the outer peripheral surface of the said roll metal mold | die is adjusted by flowing a medium inside the said roll metal mold | die.

  According to another preferred embodiment of the present invention, the active energy ray-curable composition is supplied by being applied to one surface of the translucent substrate, and is applied to the translucent substrate. Then, it is heated to a range of 40 degrees Celsius or more and less than 80 degrees Celsius.

  ADVANTAGE OF THE INVENTION According to this invention, the lens sheet manufacturing method which can improve the adhesiveness of a translucent base material and an active energy ray curable composition is provided, suppressing generation | occurrence | production of the curvature of a sheet | seat.

Hereinafter, a lens sheet manufacturing method according to a preferred embodiment of the present invention will be described with reference to the accompanying drawings.
First, the lens sheet manufactured by the lens sheet manufacturing method of a preferred embodiment of the present invention will be described. FIG. 1 is a schematic cross-sectional view showing a configuration of a prism sheet 1 which is a lens sheet manufactured by the lens sheet manufacturing method according to a preferred embodiment of the present invention.

  The prism sheet 1 is a surface of a backlight for a liquid crystal display device used in a portable notebook computer equipped with a color liquid crystal display device, a portable liquid crystal television, a mobile phone, a portable game machine, a portable camera, a portable video camera, or the like. It is a lens sheet used for improving the front luminance of the light source element.

  As shown in FIG. 1, the prism sheet 1 includes a sheet-like translucent base material 2, a lens portion 4 provided on one surface of the translucent base material 2, and a translucent base material. 2 and a relaxation layer 6 disposed between the lens unit 4 and the lens unit 4.

  The translucent substrate 2 transmits visible light, active energy rays such as ultraviolet rays, electron beams, and the like, for example, materials such as glass, acrylic resin, polycarbonate resin, polyester resin, vinyl chloride resin, and polymethacrylimide resin. Is processed into a film or a sheet.

  In order to improve the adhesion with the relaxation layer 6, a surface treatment for improving the adhesion may be performed on the surface of the translucent substrate 2. Examples of the surface treatment include a method of forming an easy-adhesion layer made of polyethylene resin, acrylic resin, urethane resin, and roughening. Further, the translucent substrate 2 can be subjected to other treatments such as antistatic, antireflection, and adhesion prevention between substrates.

  The lens unit 4 is constituted by triangular prism-shaped lens units (prisms) of active energy ray-curable resin arranged in parallel on one surface of the sheet-like translucent substrate 2.

  In the prism sheet 1 of this embodiment, the height of each prism (lens unit) of the lens unit 4 is about 10 to 150 μm, and the pitch of the lens unit is about 10 to 150 μm. In this embodiment, the lens unit pitch is preferably in the range of 10 to 100 μm, and more preferably in the range of 10 to 50 μm.

  In the prism sheet 1 of this embodiment, the apex angle of each prism is preferably in the range of 50 to 160 °. When the prism sheet 1 is used with a so-called edge light type surface light source element for a liquid crystal display device with the lens portion facing the liquid crystal panel, the apex angle of the prism is in the range of about 80 to 100 °, preferably The range is 85 to 95 °. When the edge light type surface light source element for a liquid crystal display device is used with the lens portion facing the light guide, the apex angle of the prism is in the range of about 50 to 75 °, preferably 55 to 70 °. It is considered as a range.

  The lens unit 4 preferably has a relatively high refractive index from the viewpoint of improving the luminance of the surface light source element, and specifically, the refractive index is preferably 1.50 or more. In particular, when the prism sheet 1 is arranged so that the prism portion faces the liquid crystal panel as in the former case, the refractive index of the lens portion 4 is preferably 1.55 or more, and is 1.6 or more. Is more preferable.

  In the present embodiment, the lens sheet includes the prism sheet 1 in which the lens unit 4 is composed of a large number of triangular prisms (lens units), but the lens sheet of the present invention is limited to this. Rather, it may be a lenticular lens sheet in which a lens unit is composed of a lens unit such as a semi-cylindrical or semi-elliptical cylinder, a lens sheet in which a lens unit is configured by a wave lens surface, a moth-eye lens surface, or the like. Good.

  The relaxation layer 6 is integrally formed of the same active energy ray curable resin as the lens unit 4. This relaxation layer 6 relieves deformation of the lens shape (surface shape of the lens portion) by replenishing the lack of resin in the lens mold due to polymerization shrinkage of the active energy ray-curable resin when the lens portion 4 is formed. It has a function.

  By forming the relaxation layer 6 to a thickness of 1 to 30% of the height (H) of the lens portion 4, the occurrence of spotted patterns due to polymerization shrinkage during curing of the active energy ray-curable composition is suppressed. be able to. If the thickness of the relaxing layer 6 is less than 1% of the lens height, the effect of relaxing the deformation of the lens shape due to polymerization shrinkage in the relaxing layer 6 tends to be insufficient. If it exceeds 50%, it becomes difficult to control the thickness of the relaxation layer 6, and the optical characteristics tend to be deteriorated due to uneven thickness (non-uniformity).

In the present embodiment, the thickness of the relaxation layer 6 is in the range of 1 to 25% of the height of the lens portion 4, and more preferably in the range of 3 to 15%.
Further, as shown in FIG. 1, when forming a detailed lens unit having a pitch or thickness of about several tens of μm, such as a prism sheet for a surface light source element of a liquid crystal display device, the relaxation layer 6 is thin. Preferably, for example, a range of about 1 to 10 μm is preferable, and a range of 1 to 5 μm is more preferable.

  The active energy ray curable resin for forming the lens sheet relaxation layer 6 and the lens portion 4 is not particularly limited as long as it is cured with active energy rays such as ultraviolet rays and electron beams.

  Examples thereof include polyesters, epoxy resins, polyester (meth) acrylates, epoxy (meth) acrylates, (meth) acrylate resins such as urethane (meth) acrylates, and the like. Among these, (meth) acrylate resins are particularly preferable from the viewpoint of optical properties. The active energy ray-curable composition used for such a cured resin is a polyvalent acrylate and / or a polyvalent methacrylate (less than, described as a polyvalent (meth) acrylate) in terms of handleability and curability. , Monoacrylate and / or monomethacrylate (less than, described as mono (meth) acrylate) and a photopolymerization initiator by active energy rays are preferred. Typical 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.

  In addition, examples of mono (meth) acrylates include mono (meth) acrylates of monoalcohols, mono (meth) acrylates of polyols, etc. In the latter case, when using a metal mold In order to reduce the difficulty of releasing from the metal mold, which is considered to be the influence of the hydroxyl group, it is preferable to use a small amount. Moreover, when using a metal mold | type, since it has high polarity also about (meth) acrylic acid and its metal salt, it is good to use it in a small quantity.

  Next, the structure of the prism sheet manufacturing apparatus which implements the lens sheet manufacturing method according to a preferred embodiment of the present invention will be described. FIG. 2 is a diagram illustrating a schematic configuration of a prism sheet manufacturing apparatus 10 that manufactures the prism sheet 1.

  As shown in FIG. 2, the prism sheet manufacturing apparatus 10 has a long translucent substrate 12 wound around an outer peripheral surface of a cylindrical roll mold 14 that is driven to rotate in the direction of arrow A. It is configured to be conveyed in the direction of the arrow B. A prism pattern (lens portion transfer pattern) having a shape complementary to the prism portion 4 of the prism sheet 1 to be manufactured is formed on the outer peripheral surface of the roll mold 14.

  As the roll mold 14, the lens unit transfer portion on the outer peripheral surface on which the prism pattern is formed is made of metal such as aluminum, brass, steel, silicon resin, polyurethane resin, epoxy resin, ABS resin, fluororesin, polymethyl It is made of a resin such as pentene resin. The prism pattern is created by cutting or Ni electroforming. From the viewpoint of heat resistance, strength, etc., it is desirable to use a lens unit transfer portion and others made of metal.

  A coating device 16 for the active energy ray curable composition is disposed on the upstream side of the roll die 14 in the conveying direction of the translucent substrate 12, and the active energy ray curable composition is disposed on one surface of the translucent substrate 12. The object 18 is configured to be applied with a product effective width. The structure of the coating device 16 is not particularly limited, and can be selected from known coating methods according to the resin viscosity and the coating film thickness. Preferably, a coating die is used. The product effective width is a range in which the lens sheet is used as a product.

  A nip roller 20 for making the thickness of the active energy ray curable composition 18 before curing uniform is disposed opposite to the roll mold 14. The translucent base material 12 coated with the active energy ray-curable composition 18 on one surface has the surface of the active energy ray-curable composition 18 coated on the roll die 14 so that the surface of the translucent substrate 12 faces the roll mold 14. It is conveyed while being sandwiched between the mold 14 and the nip roller 20. In a portion where the translucent substrate 12 is sandwiched between the roll mold 14 and the nip roller 20, a resin reservoir 24 is formed by the active energy ray-curable composition 18 pushed out by the sandwiching.

  As the nip roller 20, a metal roll, a rubber roll, or the like is used. Further, in order to make the thickness of the active energy ray-curable composition 12 uniform on the surface of the translucent substrate 12, the nip roller 20 is a roll processed with high accuracy with respect to roundness, surface roughness and the like. Is preferred. In the case of a rubber roll, the rubber hardness may be appropriately determined according to the viscosity of the active energy ray-curable composition, and is preferably in the range of 20 ° or more and less than 90 °.

Since the nip roller 20 needs to accurately adjust the thickness of the active energy ray curable composition 12, the translucent substrate 12 is sandwiched between the roll mold 14 by the pressure adjusting mechanism 24. The pressure to be controlled can be controlled.
As the pressure adjusting mechanism 24, 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.

In addition, an active energy ray irradiation device 26 is provided at a position below the roll die 14 on the downstream side of the nip roller 20 in the transport direction of the translucent substrate 12. The active energy ray irradiation device 26 irradiates the active energy ray curable composition 18 through the translucent substrate 12 with the active energy ray, and cures the active energy ray curable composition 18 on the translucent substrate 12. Let
At this time, since the prism pattern on the surface of the roll mold is transferred to the active energy ray-curable composition 18, the prism portion 4 having a shape complementary to the prism pattern on the outer peripheral surface of the mold is formed on the surface of the translucent substrate 12. Is formed.

  As the active energy ray irradiation device 26, a chemical reaction chemical lamp, a low-pressure mercury lamp, a high-pressure mercury lamp, a metal halide lamp, a visible light halogen lamp, or the like can be used. The active energy ray is, for example, 200 to 600 nm, preferably such that the accumulated energy in the wavelength range of 320 to 390 nm is, for example, 0.1 to 10 J / cm 2, preferably 0.5 to 8 J / cm 2. Irradiation is appropriate. Moreover, as an irradiation atmosphere of active energy rays, inert gas, such as air or nitrogen, argon, is mentioned.

  In addition, a tank T that stores the active energy ray-curable composition is connected to the coating device 16 for the active energy ray-curable composition via a conduit 28. A temperature-adjustable heater 30 is connected to the tank T and is configured to heat or maintain the temperature of the active energy ray-curable composition in the tank T within a temperature range of 40 degrees Celsius or more and less than 80 degrees Celsius. ing. The temperature of the active energy ray-curable composition in the tank T is preferably 40 degrees Celsius or higher and 70 degrees Celsius or lower, and more preferably 40 degrees Celsius or higher and 60 degrees Celsius or lower.

  Moreover, the manufacturing apparatus 10 of this embodiment is provided so that the jacket 32 through which the temperature-controlled medium flows covers the tank T, and the temperature of the active energy ray-curable composition in the tank T is set to 40 degrees Celsius or more. It is configured to heat or maintain in a temperature range of less than 80 degrees. The temperature of the active energy ray-curable composition in the tank T is preferably 40 degrees Celsius or higher and 70 degrees Celsius or lower, and more preferably 40 degrees Celsius or higher and 60 degrees Celsius or lower.

  Further, in the manufacturing apparatus 10 of this embodiment, the pipe 28 and the coating apparatus 16 are also provided with a temperature control device, and the temperature of the active energy ray-curable composition in these portions is set to 40 degrees Celsius or more and 80 degrees Celsius. It is configured to heat or maintain in a temperature range of less than degrees. The temperature of the active energy ray-curable composition in these portions is also preferably 40 degrees Celsius or higher and 70 degrees Celsius or lower, and more preferably 40 degrees Celsius or higher and 60 degrees Celsius or lower. The temperature control device is not particularly limited, but a temperature control device by electric heating is preferable.

  In the manufacturing apparatus 10 of the present embodiment, with such a configuration, 40 degrees Celsius or more and less than 80 degrees Celsius, preferably 40 degrees Celsius or more and 70 degrees Celsius or less, more preferably 40 degrees Celsius or more and 60 degrees Celsius or less are more preferable. The active energy ray-curable composition maintained in the temperature range of the temperature control device can be applied to the surface of the translucent substrate 12.

  In the manufacturing apparatus 10 of this embodiment, the active energy ray-curable composition 18 applied to the translucent substrate 12 between the roll mold 14 and the coating apparatus 16 in the conveyance path of the translucent substrate 12. Is provided at a temperature of 40 degrees Celsius or higher and lower than 80 degrees Celsius, preferably 40 degrees Celsius or higher and 70 degrees Celsius or lower, more preferably 40 degrees Celsius or higher and 60 degrees Celsius or lower. It has been. Examples of the heating device 34 include an infrared irradiation device and a hot air blowing device.

FIG. 3 is a sectional view taken along the longitudinal axis of the roll mold 14. As shown in FIG. 3, the roll die 14 has a flow path forming insert 14 a disposed therein. A temperature adjustment mechanism configured to allow a fluid at a desired temperature to flow into the flow path 14b formed by the insert 14a and adjust the surface temperature of the roll mold 14 is provided.
Moreover, as shown in FIG. 4, the structure which provided the baffle plate 14c inside the roll metal mold | die 14, and formed the flow path 14d of the bending shape may be sufficient.

  In this embodiment, by applying a fluid having a desired temperature into the flow path and adjusting the temperature of the outer peripheral surface of the roll mold 14, it is applied to the surface of the translucent substrate 12 wound around the roll mold 14. The temperature of the active energy ray curable composition 18 can be maintained within a range of 20 degrees Celsius or more and less than 40 degrees Celsius during curing.

  The temperature control of the roll mold 14 may be performed by a commercially available heat pipe type cooling roll, a precision induction heating roll jacket roll, a precision fluid circulation roll hybrid roll, or the like.

  The prism sheet manufacturing apparatus 10 having such a configuration controls the operation of the temperature control device for the medium supplied to the jacket 32, the conduit 28, and the temperature control device of the coating device 16, and applies it to the translucent substrate 12. The temperature of the active energy ray-curable composition 18 at the time of forming is set to a temperature range of 40 degrees Celsius or more and less than 80 degrees Celsius, preferably 40 degrees Celsius or more and 70 degrees Celsius or less, more preferably 40 degrees Celsius or more and 60 degrees Celsius. It is comprised so that it may be set as the temperature range below a degree.

  When the temperature of the active energy ray-curable composition 18 is less than 40 degrees Celsius, there is no effect of applying in advance in the effective width of the product, the adhesion with the translucent substrate 12 is not improved, and the roll mold 14 has a problem such that a cured product of the active energy ray-curable resin adheres to the material. On the other hand, if it exceeds 80 degrees Celsius, the translucent substrate 12 is softened, which is not preferable.

  The operation of the heating device 34 is also controlled, and the temperature of the active energy ray-curable composition after being applied to the translucent substrate 12 is in the range of 40 degrees Celsius or more and less than 80 degrees Celsius, preferably 40 degrees Celsius or more. It is configured to be maintained in a range of 70 degrees Celsius or less, more preferably in a range of 40 degrees Celsius or more and 60 degrees Celsius or less.

In this embodiment, in addition to the temperature adjustment by the jacket 32, the temperature adjustment by the pipe 28 and the coating device 16, the temperature adjustment by the heating device 34, the roll die 14 is wound around the roll die 14 by the temperature adjustment mechanism. The temperature of the active energy ray-curable composition 18 applied to the surface of the translucent substrate 12 can be maintained within a range of 20 degrees Celsius or more and less than 40 degrees Celsius at the curing start point. Yes.
The curing start point is a point where the active energy ray curable composition 18 is cured by the active energy rays while being sandwiched between the translucent substrate 12 and the roll mold 14.

When the temperature at the curing start point is less than 20 degrees Celsius, there is no effect of controlling the temperature of the active energy ray-curable composition 18 applied in advance to the translucent substrate 12 with an effective product width, and the translucent substrate 12 and the active energy ray curable composition 18 are not improved in adhesion, and problems such as the cured product of the active energy ray curable resin adhering to the roll die 14 occur.
On the other hand, when the temperature is 40 degrees Celsius or more, the viscosity and density of the active energy ray-curable composition are lowered, the shrinkage rate when polymerized and cured is large, and the warp of the sheet is undesirably increased.

  However, in the prism sheet manufacturing apparatus of the present embodiment, the temperature of the active energy ray-curable composition at the time of curing (curing start point) is in the range of 20 degrees Celsius or more and less than 40 degrees Celsius. There is no problem.

  In such a prism sheet manufacturing apparatus of the present embodiment, the active energy ray-curable composition is applied from the coating apparatus 16 to one surface of the long translucent substrate 12 conveyed toward the roll mold 14. 18 is applied. The temperature of the active energy ray-curable composition 18 at this time controls the operation of the temperature control device of the medium supplied to the jacket 32, the conduit 28, and the temperature control device of the coating device 16, and is 40 to 80 degrees Celsius. The temperature is less than 40 degrees Celsius, preferably 40 degrees Celsius or more and 70 degrees Celsius or less, more preferably 40 degrees Celsius or more and 60 degrees Celsius or less.

  Furthermore, the active energy ray-curable composition 18 applied to the translucent substrate 12 by the heating device 34 provided in the conveyance path to the roll mold 14 is a temperature of 40 degrees Celsius or more and less than 80 degrees Celsius, preferably Is maintained at a temperature not lower than 40 degrees Celsius and not higher than 70 degrees Celsius, more preferably not lower than 40 degrees Celsius and not higher than 60 degrees Celsius.

  Thus, the active energy ray-curable composition maintained at a temperature of 40 degrees centigrade or more and less than 80 degrees centigrade, preferably a temperature of 40 degrees centigrade or more and 70 degrees centigrade or less, more preferably a temperature of 40 degrees centigrade or more and 60 degrees centigrade or less. The translucent substrate 12 to which the object 18 is applied is wound around the roll die 14 so that the active energy ray-curable composition 18 contacts the outer peripheral surface of the roll die 14, and the active energy ray irradiation device The active energy ray-curable composition 18 on the translucent substrate 12 is cured by receiving the active energy ray from 26.

  At this time, since the prism pattern on the outer peripheral surface of the roll mold 14 is transferred to the active energy ray-curable composition 18, the shape of the prism pattern on the surface of the translucent substrate 12 is complementary to the prism pattern on the outer peripheral surface of the mold. The prism part 4 is formed and the translucent base material 12 becomes a long plate sheet.

  The roll mold 14 has the temperature of the active energy ray-curable composition 18 applied to the surface of the translucent substrate 12 wound around the outer peripheral surface by a temperature adjusting mechanism 14a including an internal flow path 14b. The curing start point is maintained within a range of 20 degrees Celsius or more and less than 40 degrees Celsius.

  The present invention is not limited to the above-described embodiment, and various changes and modifications can be made within the scope of the technical idea described in the claims.

  In the prism sheet manufacturing apparatus of the above embodiment, the active energy ray-curable composition is heated to a predetermined temperature before being applied to the translucent substrate 12, but the jacket 32, the pipe line 28, and A configuration in which the active energy ray-curable composition is heated to a predetermined temperature after being applied to the translucent substrate 12 without providing the temperature adjusting mechanism in the coating device 16 may be employed.

  Further, the temperature can be adjusted by any one of temperature adjustment by the jacket 32, temperature adjustment by the pipe 28 and the coating device 16, temperature adjustment by the heating device 34, temperature adjustment of the roll mold 14, or an appropriate combination thereof. A configuration in which the temperature of the energy beam curable composition 18 is maintained within a range of 20 degrees Celsius or more and less than 40 degrees Celsius at the curing start point on the outer peripheral surface of the roll mold.

Next, the present invention will be described in more detail with reference to examples.
[Example 1]
A steel roll with a diameter of 200 mm and a drawing length of 600 mm is subjected to surface polishing, a hard copper plating with a thickness of 200 μm and a Vickers hardness of 200 Hv on the outer surface, and a roll body with a hard copper plating on the surface, a pitch of 50 μm, high A prism portion transfer pattern is formed to transfer and form a prism portion formed by juxtaposing a large number of prism rows of 25 μm in length and 90 ° in apex angle with a right angled isosceles triangle, and the prism portion transfer pattern processing portion has a thickness of 3 μm. An electroless nickel plating treatment was performed to obtain a roll mold.

  As in the embodiment shown in FIG. 3, the roll mold has a flow path for circulating a temperature-controlled medium inside, and appropriately sets the temperature of the medium flowing through the flow path. By doing so, the temperature of the outer peripheral surface is adjusted.

  An NBR rubber roll (nip roller) having a rubber hardness of 80 ° was disposed so as to be close to the roll mold obtained as described above. A 125mm thick Toyobo polyester film (translucent substrate), which is slightly wider than the roll mold, is supplied between the roll mold and the nip roller along the roll mold, and is connected to the NBR rubber roll. A polyester film made by Toyobo was nipped between the NBR rubber roll and the roll mold by a cylinder (pressure adjusting mechanism).

  The operating pressure of the pneumatic cylinder at this time was 0.1 Mpa. As a pneumatic cylinder, an SMC air cylinder having an air tube diameter of 32 mm was used. Furthermore, an ultraviolet irradiation device (active energy ray irradiation device) was installed below the roll mold. As the ultraviolet irradiation device, a high-pressure mercury lamp having a lamp emission length of 70 cm and 160 W / cm was used.

  The ultraviolet curable composition (active energy ray curable composition) was put into a resin tank (tank). The resin tank was entirely made of stainless steel (SUS304) in contact with the ultraviolet curable composition. In addition, it has a jacket for controlling the liquid temperature of the ultraviolet curable composition,

  Water adjusted to 25 degrees Celsius by a heater was supplied to the jacket, and the liquid temperature of the ultraviolet curable composition in the resin tank was maintained at 25 degrees Celsius. Further, the foam generated at the time of charging was removed by deaeration by evacuating the resin tank with a vacuum pump.

The UV-curable composition is as follows, and the viscosity is 150 mPa · S / 50 ° C. phenoxyethyl acrylate 50 parts by weight (Osaka Organic Chemical Company Biscoat # 192)
50 parts by weight of bisphenol A-diepoxy-acrylate (epoxy ester 3000A manufactured by Kyoeisha Yushi Chemical Co., Ltd.)
2-Hydroxy-2-methyl-1-phenyl-propan-1-one (Darocur 1173 manufactured by Cibagayki Co., Ltd.) was adjusted to 1.5 parts by weight.

  The inside of the resin tank is returned to normal pressure, and the UV curable composition whose temperature is controlled at 25 degrees Celsius by a Takumina gear pump is applied to a polyester film (translucent substrate) manufactured by Toyobo from a Y die roll T die. It was applied to. The temperature of the applied UV curable composition was 25 degrees Celsius. Next, with a hot air generator (heating device) manufactured by Takezuna Seisakusho, hot air of 40 degrees Celsius was blown onto the ultraviolet curable composition on the polyester film manufactured by Toyobo, and the temperature of the ultraviolet curable composition was controlled to 40 degrees Celsius.

  Next, the temperature-controlled water at 25 degrees Celsius is circulated through the flow path of the roll mold at a flow rate of 70 liters / minute, so that the ultraviolet curable composition becomes between the Toyobo polyester film and the roll mold. The temperature of the outer peripheral surface of the roll mold at the curing start point was controlled to 25 degrees Celsius.

  While rotating the roll mold in the direction of the arrow at a peripheral speed of 8 m per minute with Mitsubishi Electric AC servo 200W (reduction ratio 1/100), the UV curable composition was placed between the Toyobo polyester film and the roll mold. While being sandwiched, ultraviolet rays were irradiated from an ultraviolet irradiation device to polymerize and cure the ultraviolet curable composition, thereby transferring the prism portion transfer pattern of the roll mold. Thereafter, the mold was released from the roll mold to obtain a long prism sheet (lens sheet).

<Evaluation method of characteristics>
The obtained prism sheet of Example 1 was evaluated by the following method.
(1) Initial adhesion Using a prism sheet immediately after production, it was evaluated according to the following criteria in accordance with the grid pattern method (JIS K5400).
○: 6 points or more ×: Less than 6 points (2) Warpage A prism sheet cut to 188 mm in length and 250 mm in width is placed on a flat stage with the prism surface facing upward, and the vertical distances from the stage surface to the four corners are measured. The average value is evaluated.
An average value of less than 0.5 mm was defined as good warpage, and an average value greater than 0.5 was defined as poor warpage.

<Characteristic evaluation results>
Table 1 shows the results.

[Example 2]
An ultraviolet curable composition whose temperature is controlled at 45 degrees Celsius is applied from a Yuri roll T-die to a polyester film (translucent substrate) made by Toyobo, and 60 degrees Celsius using a hot air generator (heating apparatus) manufactured by Takezuna Seisakusho. The temperature of the UV curable composition was controlled to 60 degrees Celsius by blowing hot air at a temperature to the UV curable composition on the Toyobo polyester film, and the temperature of the curing start point of the UV curable composition was controlled to 35 degrees Celsius. Except for this, a long prism sheet was obtained in the same manner as in Example 1.
The characteristics were evaluated in the same manner as in Example 1. The results are shown in Table 1.

[Comparative Example 1]
An ultraviolet curable composition whose temperature was controlled at 25 degrees Celsius was applied from a Y die roll T-die to a Toyobo polyester film (translucent substrate), and a hot air generator (heating apparatus) manufactured by Takezuna Seisakusho was used. Was blown onto the ultraviolet curable composition on the polyester film made by Toyobo to control the temperature of the ultraviolet curable composition to 35 degrees Celsius, and the temperature at the curing start point of the ultraviolet curable composition was controlled to 25 degrees Celsius. Except for this, a long prism sheet was obtained in the same manner as in Example 1.
The characteristics were evaluated in the same manner as in Example 1. The results are shown in Table 1.

[Comparative Example 2]
An ultraviolet curable composition whose temperature is controlled to 50 degrees Celsius is applied to a Toyobo polyester film (translucent substrate) from a Yuri roll T die, and 60 degrees Celsius by a hot air generator (heating apparatus) manufactured by Taketsuna Seisakusho. Was blown onto the ultraviolet curable composition on the polyester film manufactured by Toyobo to control the temperature of the ultraviolet curable composition to 60 degrees Celsius, and the temperature at the start of curing of the ultraviolet curable composition was controlled to 45 degrees Celsius. Except for this, a long prism sheet was obtained in the same manner as in Example 1.
The characteristics were evaluated in the same manner as in Example 1. The results are shown in Table 1.

[Comparative Example 3]
An ultraviolet curable composition whose temperature was controlled at 25 degrees Celsius was applied from a Y die roll T-die to a Toyobo polyester film (translucent substrate), and the temperature at the start of curing of the ultraviolet curable composition was 45 degrees Celsius. A long prism sheet was obtained in the same manner as in Example 1 except that the above was controlled.
The characteristics were evaluated in the same manner as in Example 1. The results are shown in Table 1.

  As is apparent from Table 1, the prism sheet of the example within the scope of the present invention was excellent in initial adhesion and in terms of warpage. In contrast, although the warpage of the prism sheet of Comparative Example 1 was good, the initial adhesion was poor. Moreover, although the initial adhesiveness of the prism sheet of Comparative Example 2 was excellent, the warpage was inferior. Furthermore, the prism sheet of Comparative Example 3 was inferior in both initial adhesion and warpage.

It is typical sectional drawing which shows the structure of the lens sheet (prism sheet) manufactured by the lens sheet manufacturing method of the preferable embodiment of this invention. It is drawing which shows schematic structure of the prism sheet manufacturing apparatus which enforces the lens sheet manufacturing method of the preferable aspect of this invention. It is sectional drawing along the longitudinal direction axis line of the roll metal mold | die used with the prism sheet manufacturing apparatus of FIG. It is sectional drawing along the longitudinal direction axis line of the modification of the roll metal mold | die of FIG.

Explanation of symbols

1: Prism sheet 2: Translucent base material 4: Lens unit 6: Relaxation layer 10: Prism sheet manufacturing apparatus 12: Long translucent base material 14: Roll mold 16: Coating apparatus 18: Active energy ray curing Composition 20: nip roller 26: active energy ray irradiation device

Claims (5)

An active energy ray-curable composition is disposed between an outer peripheral surface of a roll mold having a lens part transfer pattern formed on the outer peripheral surface and a translucent substrate, and the active energy ray curing is performed through the translucent substrate. The active energy ray curable composition is irradiated with active energy rays to cure the active energy ray-curable composition, and the lens portion having a shape complementary to the lens portion transfer pattern is cured on the surface of the translucent substrate. A lens sheet manufacturing method formed of resin,
The active energy ray-curable composition is in a temperature range of 40 degrees Celsius or more and less than 80 degrees Celsius before the curing, and at the time of curing, the active energy ray curable composition is in a range of 20 degrees Celsius or more and less than 40 degrees Celsius.
A method for producing a lens sheet. The active energy ray-curable composition is supplied by being applied to one surface of the translucent substrate,
The temperature at the time of supply of the active energy ray-curable composition is in a range of 40 degrees Celsius or more and less than 80 degrees Celsius.
The lens sheet manufacturing method according to claim 1. The active energy ray curable composition is controlled to a temperature range of 20 degrees Celsius or more and less than 40 degrees Celsius during the curing by adjusting the temperature of the outer peripheral surface of the roll mold.
The lens sheet manufacturing method according to claim 1 or 2. By flowing a medium inside the roll mold, the temperature of the outer peripheral surface of the roll mold is adjusted,
The lens sheet manufacturing method according to claim 3. The active energy ray-curable composition is supplied by being applied to one surface of the translucent substrate,
After being applied to the translucent substrate, it is heated to a range of 40 degrees Celsius or more and less than 80 degrees Celsius.
The lens sheet manufacturing method according to claim 1.

Images