JP6249587B2 - Manufacturing method of optical sheet - Google Patents

Description

  The present invention relates to an EL element (electroluminescence element) used for a flat panel display, a backlight for liquid crystal, a light source for illumination, an electrical decoration, a light source for signage, and the like, and a display device, a display device, and a liquid crystal display using the EL element The present invention relates to an optical sheet manufacturing method, an optical sheet, an EL element using the optical sheet, and a lighting device including the same.

  This type of optical sheet is produced by providing a specific uneven pattern (lens pattern) on a translucent substrate. In order to give such a concavo-convex pattern, patterning is performed on a cylinder-shaped or plate-shaped mold using engraving or drawing represented by a lathe cutting method, and this is used as a matrix for the surface of a translucent substrate. The pattern is transferred to and formed. Alternatively, a sheet on which a pattern is transferred from the mother die onto a substrate is retransferred as a mother die. Alternatively, a production method is used such as providing a concavo-convex pattern by laying fine particles on the surface of a translucent substrate (see, for example, Patent Document 1).

Japanese Patent Laid-Open No. 8-211205

However, the above-described conventional technology has the following problems.
That is, in the optical sheet according to the above-described conventional technology, the purpose of the display device is to control the optical characteristics in the horizontal direction and the vertical direction and to impart light diffusion performance. The purpose of the EL lighting device is to improve light extraction efficiency, improve surface scratch resistance, and light diffusion performance.
However, at present, the backlight unit in the display device uses a light source having a very strong directivity, so there is a problem that the variation in the amount of light caused by the light source is visually recognized as a light and dark pattern. .

In addition, in the EL lighting device, when an EL unit of a multi-photon method stacked in three color layers is used, a specific wavelength is emitted with a protruding intensity at a specific angle. There has been a problem that a defect of color misregistration in which the color of illumination changes occurs.
In order to solve these problems, it is better that the intensity of the light beam emitted toward the observer side is uniform for each wavelength and the intensity of the integrated light is uniform for each place. However, it has been studied to use a member having lens performance on the surface or a member having both, but it is basically a member made by using molten resin molding and used for the surface layer of an optical member. In such applications, the scratch resistance is insufficient.

  In contrast, when a lens using an active energy ray-curable resin is used with a patterned cylindrical mold as a matrix, the active energy is superior to the thermoplastic resin used in molten resin molding. By using a linear curable resin, although there is an advantage in surface scratch resistance, the degree of dependence on the light distribution from the light source is strong, and it is difficult to impart strong internal diffusion performance. In addition, the light distribution characteristics due to the lens shape greatly affect the emitted light, and it becomes difficult to convert these into a light distribution with uniform intensity for each wavelength when light with strong directivity is incident. There was room for improvement in that regard.

  The present invention has been made in view of the above-mentioned problems, by using a cylindrical mold as a pattern matrix and creating it using an active energy ray-curable resin on a translucent substrate, Optical sheet manufacturing method and optical sheet capable of obtaining desired lens shape and strong diffusion performance, and high surface scratch resistance performance, EL element using optical sheet, and illumination device including the same The purpose is to provide.

In order to achieve the above object, in the method for producing an optical sheet according to the present invention, an optical function having an uneven portion on the surface using an active energy ray-curable resin on one surface of a translucent substrate continuous in a sheet form. a method of manufacturing an optical sheet layer has been applied, a cylinder shape the concavo-convex portion is concave-convex structure is imparted as a molding release auxiliary section to the surface of the translucent base through the active energy ray-curable resin The die in the width direction of the die in the crimping portion in a state where the die and the translucent substrate that are not via the active energy ray curable resin are crimped are formed. The contact length ratio A with the width-direction tangent length of the translucent substrate with respect to the length is 0.1 ≦ A ≦ 0.7, and the contact length ratio A is the translucency at the time of forming the concavo-convex portion. tension stability and thickness of the sheet in the flow direction of sexual substrate A value of evaluating, and the forming mold release auxiliary section, the a translucent substrate without a contact point, and a contact portion and a non-contact portion between the translucent substrate and the mold It is repeated at least once and is manufactured such that the distance h1 between one surface of the translucent substrate and the concave portion of the molding release assisting portion in the normal direction satisfies 20 μm <h1 <200 μm. It is characterized by.

In the present invention, the volume of the optical function part is ensured by manufacturing the distance h ₁ with the concave part of the mold release auxiliary part in the normal direction of the translucent substrate so that 20 μm <h ₁ <200 μm. And an optical sheet having sufficient diffusibility can be obtained. In addition, it is possible to suppress the occurrence of cohesive failure when the resin is peeled from the mold, and it is possible to prevent the problem of causing appearance defects.
Further, the width-direction tangential length of the light-transmitting substrate with respect to the width-direction tangential length of the mold in the pressure-bonding portion in a state where the mold and the light-transmitting substrate are not bonded via the active energy ray-curable resin. By setting the contact length ratio A to 0.1 ≦ A ≦ 0.7, it is possible to ensure the length of the contact portion when the permeable substrate and the die are pressure-bonded. The tension in the flow direction of the permeable substrate can be stabilized. In addition, it is possible to ensure the degree of freedom in the vertical direction of the permeable substrate, and it is possible to prevent the occurrence of wrinkles due to the variation in the thickness of the permeable substrate. Therefore, the thickness dimension of the optical function unit can be varied depending on the installation conditions.
In this way, a desired lens shape and strong diffusion performance can be obtained by using an active energy ray-curable resin on a translucent substrate using a cylindrical mold as a pattern matrix. And high surface scratch resistance can be obtained.

In the method for manufacturing an optical sheet according to the present invention, the maximum height difference between the outermost surface of the optical function portion provided in the optical function layer and the recess of the mold release auxiliary portion is h2, and the total thickness of the optical function portion is h. In this case, 0.01 ≦ h2 / h ≦ 0.2.
In this case, since it is substantially flat and does not cause mold release, and unevenness on the surface falls within the lens effect, an optical sheet capable of controlling the optical function called a diffusion function can be provided.

Moreover, in the manufacturing method of the optical sheet which concerns on this invention, the uneven | corrugated | grooved part of a shaping | molding mold release auxiliary | assistant part may be a shape which continued in one direction.

Further, in the method for producing an optical sheet according to the present invention, the optical functional layer is 1% in which the molding auxiliary in the active energy ray-curable resin is E as a percentage of the volume of the molding auxiliary to the total volume of the optical functional layer. ≦ E ≦ 35% is added.

  In the present invention, the active energy ray-curable resin that is the material of the lens group is preliminarily added with a molding aid that can adjust the curing shrinkage rate and releasability, so that these materials are relatively pressure-bonded to the matrix. When the lens group is cured and molded, the delamination phenomenon in which the molding resin separates from the matrix before curing during cure shrinkage is prevented, and the resin does not remain on the matrix and the resin is not taken off, so the transfer rate is good Thus, an optical sheet having high molding stability can be obtained.

In the method for producing an optical sheet according to the present invention, the molding aid is a fine particle, and preferably 0.01 <r1 / h1 <0.1, where r1 is the average particle diameter.

In this case, the viscosity of the active energy ray-curable resin for increasing the number of fine particles necessary for obtaining sufficient diffusibility does not significantly increase, and the transfer rate does not decrease. Moreover, since the film strength after the resin is cured can be ensured, it is possible to suppress the occurrence of cohesive failure at the time of peeling. Furthermore, it is possible to suppress the occurrence of the delamination phenomenon that the fine particles are randomly peeled from the cured portion to the mold without deforming the surface shape of the optical function portion.
Therefore, it is easy to determine stable molding conditions, and it is possible to appropriately select the addition amount of fine particles in accordance with various physical properties such as desired diffusion performance and adhesion performance, and fine particle and active energy ray curability. There is an advantage that the selection of the resin is simple.

According to the method for producing an optical sheet and the optical sheet of the present invention, a cylindrical mold is used as a pattern matrix, and a desired shape is obtained by using an active energy ray-curable resin on a translucent substrate. It is possible to obtain a lens shape and strong diffusion performance, and it is possible to obtain an optical sheet having a surface scratch resistance higher than that of an optical sheet having the same shape produced by general molten resin molding.
Moreover, the EL element using the optical sheet manufactured by such a manufacturing method and the lighting device including the same can improve the light use efficiency by including the optical sheet described above.

It is sectional drawing which shows schematic structure of the EL illumination element containing the optical sheet by the 1st Embodiment of this invention. It is a longitudinal cross-sectional view of the optical sheet shown in FIG. It is a schematic diagram which shows the manufacturing method of the optical sheet by 1st Embodiment. It is a perspective view which shows schematic structure of an engraving tool unit. It is a longitudinal cross-sectional view which shows schematic structure of a metal mold | die. It is a longitudinal cross-sectional view which shows a metal mold | die and an active ray irradiation apparatus. It is a figure which shows schematic structure of EL illumination element containing the optical sheet by the 2nd Embodiment of this invention. It is a longitudinal cross-sectional view of the optical sheet shown in FIG. It is a longitudinal cross-sectional view which shows schematic structure of the metal mold | die by 2nd Embodiment. (A)-(c) is a longitudinal cross-sectional view which shows schematic structure of the metal mold | die by a modification. It is a longitudinal cross-sectional view which shows the metal mold | die and active ray irradiation apparatus by 3rd Embodiment, Comprising: It is a figure based on the metal mold | die of FIG.10 (c). It is sectional drawing which shows schematic structure of the EL illumination element containing the optical sheet by 4th Embodiment.

  Hereinafter, an optical sheet manufacturing method and an optical sheet according to an embodiment of the present invention, an EL element using the optical sheet, and an illumination device including the same will be described with reference to the drawings.

(First embodiment)
First, the EL element according to the present embodiment includes, for example, an EL illumination device, a display device, or an illumination including various display devices such as a liquid crystal display device as a light emitting unit, which is disposed on the back surface of an image display element such as a liquid crystal device. Used in the apparatus.
An EL illumination element 1 (EL element) shown in FIG. 1 is configured by laminating an optical sheet 3 according to the first embodiment on a light emission side surface of an EL panel 2.

The EL panel 2 includes a translucent first substrate 5 disposed on the light emission side, a second substrate 6 disposed on the back side of the first substrate 5, and the first substrate 5 and the second substrate 6. The light emitting structure 7 sandwiched between them is integrally laminated. The light emitting structure 7 includes an anode 8 disposed on the back surface side of the first substrate 5, a cathode 9 disposed on the front surface side of the second substrate 6, and a light emitting layer 10 sandwiched between the anode 8 and the cathode 9. It consists of and.
The light emitting structure 7 emits light when the light emitting layer 10 applies a voltage to the anode 8 and the cathode 9, and various conventionally known structures can be employed. The EL panel 2 applies a voltage between the anode 8 and the cathode 9 to emit light from the light emitting layer 10, and this light passes through the first substrate 5 and enters the optical sheet 3. The light is transmitted and emitted to the outside.

  The optical sheet 3 shown in FIG. 2 is laminated on the upper surface (outermost surface) which is the surface on the light emission side of the first substrate 5 of the EL panel 2 via the bonding layer 4. The plurality of unit lenses 12A (uneven layers of the molding release assisting portion) laminated on the translucent substrate 11 are formed with the lens group 12 (optical function portion) in which the two-dimensional directions are arranged. Yes. The unit lens 12A is configured, for example, by arranging cylindrical lenses having a substantially semi-elliptical or semi-circular cross section so as to intersect each other in a direction perpendicular to each other. Each of these cylindrical lenses constitutes a unit lens 12A, and a combination of these constitutes a lens group 12.

  For the bonding layer 4, a pressure-sensitive adhesive or an adhesive can be used, and any of resin systems such as acrylic and urethane can be used, and can be appropriately selected depending on the material of the base material and the thermoplastic resin. More specifically, as the acrylic pressure-sensitive adhesive, a pressure-sensitive adhesive layer having excellent heat resistance can be obtained by appropriately crosslinking an acrylic polymer. As specific means of the crosslinking method, a compound having a group capable of reacting with a carboxyl group, a hydroxyl group, an amino group, an amide group, or the like appropriately included as a crosslinking base point in an acrylic polymer such as an isocyanate compound, an epoxy compound, or an aziridine compound. There is a method using a so-called cross-linking agent that is added and reacted. Among these, examples of the isocyanate compound include aromatic isocyanates such as tolylene diisocyanate and xylene diisocyanate, alicyclic isocyanates such as isophorone diisocyanate, and aliphatic isocyanates such as hexamethylene diisocyanate. Further, fine particles may be added to these for the purpose of adjusting the diffusion performance and the adhesion with the glass substrate. The optical sheet 3 is disposed on the outermost surface of the EL panel 2 through the bonding layer 4, so that the EL lighting element 1 having a uniform alignment characteristic of emitted light can be obtained.

The cross-sectional shape of the unit lens 12A is not limited to the above-described substantially semi-elliptical shape or substantially semi-circular shape, and other appropriate cross-sectional shapes can be adopted (described later). Moreover, the shape of the unit lenses 12A arranged is not limited to one type, and the lens group 12 may be configured by combining two or more types of shapes of three or more types.
The lens group 12 may be configured by unit lenses 12A arranged in a one-dimensional direction, but is preferably configured by arranging them in a two-dimensional direction. The two-dimensional arrangement of the unit lenses 12A is not only a configuration in which the cylindrical unit lenses 12A extending in one direction are arranged in parallel to a direction orthogonal to each other, but the unit lenses 12A are arranged in a dot-like direction orthogonal to each other. Examples thereof include a configuration arranged in a honeycomb shape, and the like.

Here, the material of the optical sheet 3 will be described.
As the translucent base material 11, for example, a synthetic resin such as a polyester resin, a polyolefin resin, a polystyrene resin, a methacrylic resin, a polycarbonate resin, a vinyl chloride resin, a cycloolefin polymer, or a composite thereof is used.
It is also possible to use one in which a surface treatment such as an easy adhesion layer is applied to at least one surface of the translucent substrate 11. By adopting such a configuration, the adhesion of the EL panel 2 to the first substrate 5 and the adhesion to the lens group 12 are enhanced.

Further, an active energy ray curable resin is used for the lens group 12 having a plurality of types of unit lenses 12A. As the active energy ray curable resin, for example, an ultraviolet curable photopolymer is used, and specifically, a known resin containing an acrylic polymer, an acrylic monomer, a photoinitiator, or the like is used. When forming using an active energy ray-curable resin as the material of the lens group 12, a material that is cured and has adhesiveness when irradiated with active energy rays (for example, ultraviolet rays) can be used.
In order to manufacture the lens group 12, as an active energy ray-curable resin, for example, an ultraviolet curable photopolymer, specifically, a molding containing an acrylic polymer, an acrylic monomer, a photoinitiator, or the like, which will be described later. An auxiliary agent is mixed and an ultraviolet curable photopolymer is applied onto the light-transmitting substrate 11. And the optical sheet 3 which has the desired lens group 12 can be obtained by making it harden | cure in the state which pressure-bonded the metal mold | die (plate) of the mold in which the pattern of the lens group 12 was previously shape | molded.

Here, when an active energy ray curable resin is used as a material of the lens group 12 and a mother die (plate) is pressure-bonded and formed, a portion having a very low resin adhesion such as a flat portion in the external shape of the unit lens 12A When this occurs, when the active energy ray-curable resin is cured, in this part, the part is released from the mother mold faster than the uneven part made of the uneven part, and the part becomes uneven and visible. A phenomenon called “Delami” occurs.
Further, in the molding method of the lens group 12, the surface of the concavo-convex pattern portion (lens pattern) of the mother die is rusted due to corrosion or the like, and the concavo-convex portion of high aspect that is the ratio of the height and width of the unit lens 12A. In such a case, it is difficult to peel off from the mother mold after the actinic ray curable resin is cured, and there is a possibility that a phenomenon of “resin removal” that the resin remains on the mother mold side may occur.
Therefore, in the first embodiment, a molding aid is added to the active energy ray-curable resin forming the lens group 12 in a predetermined range in advance to prevent delamination and resin removal. The molding aid can exhibit a function of adjusting the curing shrinkage rate and release property of the active energy ray-curable resin.

Next, the manufacturing method of the optical sheet 3 mentioned above is demonstrated based on drawing.
As shown in FIG. 3, the optical sheet 3 manufacturing apparatus 20 includes a translucent substrate roll 21 that feeds the translucent substrate 11 continuous in a sheet shape as a translucent substrate sheet 11 </ b> A, and a translucent material. A resin supply unit 22 for applying an active energy ray-curable resin in which a fine particle forming auxiliary is mixed in advance to the base sheet 11A, and a mold in which the transfer shape of the lens group 12 is formed on a cylindrical surface are formed. Irradiate active energy rays to the metal cylindrical mother die (die 40), the translucent base material pressure-bonding roll 24 crimped to the die 40, and the active energy ray-curable resin applied to the die 40. Then, an active energy ray irradiation device 50 that cures the resin and an optical sheet roll 26 that winds the translucent base sheet 11A on which the lens group 12 is molded are provided.

Here, an example of a mold manufacturing method used for optical sheet manufacturing will be described with reference to FIG.
The mold 40 is formed, for example, by plating another metal 31 in layers on a substantially cylindrical iron core 33. The other metal 31 referred to here is, for example, copper or nickel, and can be appropriately selected depending on the shape of the concave / convex pattern to be applied to the mother die 40, and for the purpose of rust prevention and surface protection after the concave / convex pattern 31a is applied. A metal plating such as chrome can also be applied. Further, a method for imparting an uneven pattern to the mother die 40 can be selected as appropriate, such as a cutting method using a lathe, a laser drawing method, or a corrosion method, or the mother die 40 can be manufactured by appropriately combining these methods. .

Next, a method for manufacturing the optical sheet 3 using the manufacturing apparatus 20 will be described.
First, the translucent base material sheet 11 </ b> A in which the translucent base material 11 continues in a sheet shape is fed out from the translucent base material roll 21, and the translucent material is transmitted from the resin supply unit 22 disposed facing the receiving roll 27. An active energy ray-curable resin in which a fine particle forming auxiliary is added in advance and uniformly dispersed is applied onto the base sheet 11A.

The translucent substrate sheet 11A to which the active energy ray curable resin is applied is such that the surface on which the active energy ray curable resin is applied faces the mold 40 and the mother die 40 is bonded to the translucent substrate. The active energy ray-curable resin is sandwiched between the rolls 24 and pressed, and the active energy ray-curable resin is molded along the uneven pattern of the mold 40.
The translucent substrate sheet 11A formed by the mold 40 is cured by an active energy ray curable resin such as ultraviolet rays irradiated from the active energy ray irradiation device 50, and the optical sheet roll 26 is passed through a tension roll. Rolled up. Then, the optical sheet 3 is obtained by cutting the translucent substrate sheet 11A for each unit of the translucent substrate 11 on which the lens group 12 is formed in a separate process.

As shown in FIG. 5, the mold including the mold 40 is provided with a pattern having concave and convex portions 42 </ b> A of the mold release assisting portion 42 and the mold optical function portion grooves 41 on the surface.
And as shown in FIG. 6, the width direction tangent length of the metal mold | die 40 in the crimping | compression-bonding part in the state by which the metal mold | die 40 and the translucent base material 11 in the state which does not interpose active energy ray curable resin were crimped | bonded The contact length ratio A with the contact portion length dimension L2 of the translucent substrate 11 with respect to L0 (the tangential length in the width direction of the translucent substrate 11) is 0.1 ≦ A ≦ 0.7. 2 ≦ A ≦ 0.6. Here, the contact part (part of the code | symbol L2) with respect to the metal mold | die 40 in the permeable base material 11 becomes a structure which does not exist in a pattern part.

When the contact length ratio A is A <0.1, the contact portion length dimension L2 when the translucent substrate 11 and the mold 40 are pressure-bonded is insufficient. There is a drawback that the tension in the flow direction of the conductive substrate 11 is not stable.
Further, when the contact length ratio A is A> 0.7, the degree of freedom in the vertical direction of the translucent substrate 11 is lost, and thus wrinkles caused by the thickness variation of the translucent substrate 11 are eliminated. In addition to the cause, it is difficult to control the thickness of the lens group 12 that forms the optical function section depending on the apparatus conditions.
Furthermore, when the contact length ratio A is 0.2 ≦ A ≦ 0.6, sufficient tension stability in the flow direction can be obtained, and a non-contact portion (portion L1 shown in FIG. 6) can be provided. Since the translucent substrate 11 sag in the vertical direction by holding, the thickness dimension h of the actual optical function part (lens group 12) can be changed by changing the resin supply amount and the tension in the flow direction of the translucent substrate 11. ₁ can be changed.

An optical sheet manufacturing method using such a mold 40 will be described in detail with reference to FIG.
As shown in FIG. 5, the optical sheet 3 is bonded by pressing an active energy ray curable resin between the mold 40 and the translucent substrate 11 and irradiating active energy rays from the active energy ray irradiating device 50. Can be obtained. At this time, it is possible to obtain a diffusable optical function part (lens group 12) by adding a molding aid different from the refractive index after curing of the active energy ray-curable resin into the resin.

Moreover, as shown in FIG. 6, the metal mold | die 40 becomes a structure by which the non-molding mold release auxiliary | assistant part 43 and the mold mold release auxiliary part 42 exist at least once or more from the edge part. The contact portion (reference L2 portion) of the mold 40 / translucent base material 11 and the non-contact portion L1 at the time of being pressure-bonded without an active energy ray curable resin being repeated at least once, The distance h ₁ between the translucent substrate 11 and the concave portion 42a of the mold release assisting portion 42 in the normal direction is 20 μm <h ₁ <200 μm, and the outermost surface in the optical function portion (lens group 12) (Reference numeral 12a in FIG. 6) and the maximum height difference between the concave portion 42a of the mold release assisting part 42 is h ₂ and the total thickness of the optical function part is h, 0.01 ≦ h ₂ /h≦0.2 It has become.

When the distance h ₁ is h ₁ ≦ 20 μm, the volume of the optical function part (lens group 12) is insufficient, and sufficient diffusibility cannot be obtained. Further, when the distance h ₁ is h ₁ ≧ 200 μm, it may cause cohesive failure when the resin is peeled off from the mold 40 and cause poor appearance.
The maximum height difference of when the ratio _h 2 / h and _{h 2} as the total thickness h is _{0.01> h} 2 / h are no longer substantially fulfill the function as trigger flat and will release further _{h 2} When /h>0.2, the unevenness on the surface produces a lens effect, making it difficult to control the optical function called the diffusion function.

Specifically, the translucent substrate 11 is made of synthetic resin such as polyester resin, polyolefin resin, polystyrene resin, methacrylic resin, polycarbonate resin, vinyl chloride resin, cycloolefin polymer, and composites thereof. It is also possible to use those in which at least one surface of the translucent substrate 11 is subjected to a surface treatment such as an easy adhesion layer, a hard coat treatment, or an antiglare treatment.
Further, the optical function unit (lens group 12) can be used that is cured and has adhesiveness when irradiated with active energy rays (for example, ultraviolet rays). For example, an ultraviolet curable photopolymer is used, and specifically, a known one containing an acrylic polymer, an acrylic monomer, a photoinitiator, and the like, to which a molding aid is added, can be used. By using the translucent substrate 11 that has been hard-coated, it is used as an optical sheet for flat panel display applications that achieves both hard-coating performance and high diffusibility by molding on the opposite side of the hard-coating process. Is possible.

  Molding aids are fine particles, such as organic particles composed of styrene resin, acrylic resin, silicone resin, urea resin, formaldehyde condensate, etc., glass beads, silica, alumina, calcium carbonate, metal oxide, etc. It is also possible to use inorganic fine particles, or pigments or pigments that have absorptivity at a specific wavelength of bubbles or visible light, and these plural types of fine particles can be used in combination.

  When the percentage of the volume Vf of the molding aid to the total volume of the lens group when the total volume of the molding aid is Vf is E, E is about 0.5% ≦ E ≦ 40%. More preferably, 1% ≦ E ≦ 35%.

In the case of E <0.5%, when the pattern of the mother die 40 is transferred onto the translucent substrate 11 using the active energy ray curable resin, the adhesive force between the cured resin and the mother die 40 However, there is no change with respect to the case where the molding auxiliary is not added, and the release property is not improved.
Moreover, in the case of E> 40%, the adhesive force between the cured resin and the translucent substrate is significantly reduced, and the reliability of the product is impaired.
In addition, when 35% <E ≦ 40%, the dispersion state of the fine particles in the resin deteriorates, the filter is clogged at the time of liquid feeding, or the matrix mold scratches due to the adhesion of the fine particle aggregates to the matrix 40 This may cause a phenomenon such as pattern clogging. Therefore, when it is desired to impart diffusibility to the lens group 12, it is desirable that 1% ≦ E.

Accordingly, when 1% ≦ E ≦ 35%, the fine particles can be dispersed and mixed with the active energy ray-curable resin relatively easily, so that the fine particles can be combined with various physical properties such as a desired pattern shape, diffusion performance, and adhesion performance. It is possible to appropriately select the amount of addition and to select the fine particles and the active energy ray-curable resin.
In addition, by adding fine particles as molding aids, it is possible to reduce shrinkage during resin curing, and it is possible to arbitrarily control the amount of addition by changing the amount added, and warping of the substrate that occurs during resin curing It is possible to obtain an optical sheet with high handling properties in which the above is suppressed.

Here, then, the diameter of the particles as a molding aid, the relationship between the distance h ₁ between the recesses 42a of the forming mold release aids 42 will be described.
When the average particle diameter of the molding aid that is fine particles is r ₁ , it is desirable that 0.01 <r ₁ / h ₁ <0.1.
In the case of 0.01 ≧ r ₁ / h ₁ , the number of fine particles necessary for obtaining sufficient diffusibility increases, so that the viscosity of the active energy ray curable resin is remarkably increased and the transfer rate is decreased. Since there is a possibility, the likelihood of the molding conditions is narrowed, and the film strength after the resin is cured is also lowered, which may cause cohesive failure at the time of peeling from the mold.
In addition, when r ₁ / h ₁ ≧ 0.1, the fine particles may deform the surface shape of the optical function part, and are randomly peeled off from the mold from the cured part when the resin is cured. A phenomenon called delamination may occur, and unevenness may occur at each peeling site, which may cause poor appearance.
Therefore, when 0.01 <r ₁ / h ₁ <0.1, it is easy to determine stable molding conditions, and the addition amount of fine particles is appropriately adjusted in accordance with various physical properties such as desired diffusion performance and adhesion performance. There are advantages that the selection can be made and the selection of the fine particles and the active energy ray-curable resin is simplified.

As described above, in the optical sheet manufacturing method and the optical sheet according to the first embodiment, the active energy ray curable resin is formed on the translucent substrate 11 by using the mold of the mold 40 as the pattern matrix. It is possible to obtain a desired lens shape and strong diffusion performance by using this, and the surface produced by general molten resin molding has an optical surface with higher scratch resistance than an optical sheet of the same shape. Sheet 3 can be obtained.
Moreover, in the EL element using the optical sheet manufactured by such a manufacturing method and the lighting device including the same, the use efficiency of light can be improved by including the optical sheet 3 described above.

  Next, other embodiments of the optical sheet manufacturing method, the optical sheet, the EL element using the optical sheet, and the lighting device including the optical sheet according to the present invention will be described with reference to the accompanying drawings. The same reference numerals are used for the same or similar members and parts as those of the embodiment, and the description thereof is omitted, and a configuration different from that of the first embodiment will be described.

(Second Embodiment)
In the EL element 1A according to the second embodiment of the present invention shown in FIGS. 7 and 8, the lens group 13 (optical function part) of the optical sheet 3A is, for example, a prism lens having a substantially triangular cross section, and has the same shape unit. Lenses 13A, 13A,... (Concavo-convex layer of molding release auxiliary portion 42) are arranged in parallel. As shown in FIG. 9, in the mold 40 </ b> A in this case, the uneven portion 42 </ b> B of the mold release assisting portion 42 is formed in a substantially triangular shape corresponding to the substantially triangular cross section of the lens group 13.

  In addition, the shape of the concavo-convex portions 42A and 42B of the molds 40 and 40A is not limited to the above-described embodiment, and is appropriately set according to the shape of the optical sheet 3. 10A to 10C show other shapes of the molds 40B, 40C, and 40D. The mold 40B shown in FIG. 10 (a) is provided with an uneven portion 42C having a substantially triangular cross section that differs in size. In addition, the mold 40C shown in FIG. 10B is formed with an uneven portion 42D having a substantially semi-circular cross section that is different in size. In addition, the mold 40D shown in FIG. 10C is provided with a concavo-convex part 42E in which a concavo-convex part 42b having a substantially triangular cross section and a concavo-convex part 42c having a substantially semi-circular cross-section different in size are mixed.

(Third embodiment)
The mold and active ray irradiation device 50 shown in FIG. 11 employ the mold 40D shown in FIG.

(Fourth embodiment)
As shown in FIG. 12, in the EL lighting element 1 </ b> B according to the fourth embodiment of the present invention, the optical sheet 3 is disposed on the outermost surface of the EL panel 2. The surface (unit lens 12 </ b> A of the lens group 12) is bonded to the glass substrate of the EL panel 2 via the bonding layer 4.
As the material of the bonding layer 4, the one described in the preceding paragraph can be used, and the outermost surface can be obtained by using the translucent substrate 11 having a hard coat or an antiglare treatment on the surface opposite to the resin molding surface. Thus, it is possible to obtain an EL illumination device 1B that imparts desired physical properties and has high diffusibility and uniform alignment characteristics of emitted light.

  The embodiments of the optical sheet manufacturing method, the optical sheet, the EL element using the optical sheet, and the lighting device including the optical sheet according to the present invention have been described above. However, the present invention is limited to the above-described embodiment. Instead, it can be changed as appropriate without departing from the spirit of the invention.

1, 1A, 1B EL lighting element (EL element)
2 EL panel 3 Optical sheet 4 Bonding layer 5 First substrate 6 Second substrate 7 Light emitting structure 8 Anode 9 Cathode 10 Light emitting layer 11 Translucent base material 12, 13 Lens group (optical function part)
12A, 13A Unit lens 20 Manufacturing equipment 40 Mold (metal cylinder base)
41 Mold optical function part groove 42 Molding release auxiliary part 42A to 42E Concavity and convexity part 42a Concave part 43 Non-molding release auxiliary part 50 Active energy ray irradiation device L0 Die width tangential length L1 Non-contact part L2 Permeability group Tangent length in width direction of material

Claims (5)

A method for producing an optical sheet in which an optical functional layer having a concavo-convex portion on its surface using an active energy ray-curable resin is provided on one surface of a translucent substrate continuous in a sheet shape,
The concavo-convex part is formed by pressure-bonding a cylindrical mold provided with a concavo-convex structure as a mold release auxiliary part on the surface of the translucent substrate through an active energy ray-curable resin, and The width-direction tangential length of the translucent base material with respect to the width-direction tangential length of the mold in the pressure-bonded portion in a state where the mold and the translucent base material are not pressed through the active energy ray-curable resin. The contact length ratio A is 0.1 ≦ A ≦ 0.7,
The contact length ratio A is a value for evaluating the tension stability and thickness in the flow direction of the sheet of the translucent substrate at the time of formation of the uneven portion,
The molding release auxiliary part and the translucent base material do not have a contact point, and the contact part and the non-contact part between the mold and the translucent base material are repeated at least once. The optical sheet is manufactured such that a distance h1 between one surface of the translucent substrate and the concave portion of the molding release assisting portion in the normal direction satisfies 20 μm <h1 <200 μm. Production method. It is a manufacturing method of the optical sheet according to claim 1,
When the maximum height difference between the outermost surface of the optical function part provided in the optical function layer and the concave part of the molding release auxiliary part is h2, and the total thickness of the optical function part is h, 0.01 ≦ h2 / A method for producing an optical sheet, wherein h ≦ 0.2.   The method for producing an optical sheet according to claim 2, wherein the uneven portion of the molding release assisting portion has a continuous shape in one direction. It is a manufacturing method of the optical sheet according to claim 1,
In the optical functional layer, the molding auxiliary agent is added in the active energy ray-curable resin as 1% ≦ E ≦ 35%, where E is a percentage of the volume of the molding auxiliary agent to the total volume of the optical functional layer . An optical sheet manufacturing method characterized by the above. 5. The method for producing an optical sheet according to claim 4, wherein the molding aid is fine particles, and 0.01 <r1 / h1 <0.1, where r1 is an average particle diameter.

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